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class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2502.05559">arXiv:2502.05559</a> <span> [<a href="https://arxiv.org/pdf/2502.05559">pdf</a>, <a href="https://arxiv.org/format/2502.05559">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Channel Estimation for RIS-Aided MU-MIMO mmWave Systems with Practical Hybrid Architecture </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Zhuo%2C+L">Liuchang Zhuo</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Ren%2C+H">Hong Ren</a>, <a href="/search/eess?searchtype=author&query=Weng%2C+R">Ruisong Weng</a>, <a href="/search/eess?searchtype=author&query=Jin%2C+S">Shi Jin</a>, <a href="/search/eess?searchtype=author&query=Swindlehurst%2C+A+L">A. Lee Swindlehurst</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+J">Jiangzhou Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2502.05559v1-abstract-short" style="display: inline;"> This paper proposes a correlation-based three-stage channel estimation strategy with low pilot overhead for reconfigurable intelligent surface (RIS)-aided millimeter wave (mmWave) multi-user (MU) MIMO systems, in which both users and base station (BS) are equipped with a hybrid RF architecture. In Stage I, all users jointly transmit pilots and recover the uncompressed received signals to estimate… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.05559v1-abstract-full').style.display = 'inline'; document.getElementById('2502.05559v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.05559v1-abstract-full" style="display: none;"> This paper proposes a correlation-based three-stage channel estimation strategy with low pilot overhead for reconfigurable intelligent surface (RIS)-aided millimeter wave (mmWave) multi-user (MU) MIMO systems, in which both users and base station (BS) are equipped with a hybrid RF architecture. In Stage I, all users jointly transmit pilots and recover the uncompressed received signals to estimate the angle of arrival (AoA) at the BS using the discrete Fourier transform (DFT). Based on the observation that the overall cascaded MIMO channel can be decomposed into multiple sub-channels, the cascaded channel for a typical user is estimated in Stage II. Specifically, using the invariance of angles and the linear correlation of gains related to different cascaded subchannels, we use compressive sensing (CS), least squares (LS), and a one-dimensional search to estimate the Angles of Departure (AoDs), based on which the overall cascaded channel is obtained. In Stage III, the remaining users independently transmit pilots to estimate their individual cascaded channel with the same approach as in Stage II, which exploits the equivalent common RIS-BS channel obtained in Stage II to reduce the pilot overhead. In addition, the hybrid combining matrix and the RIS phase shift matrix are designed to reduce the noise power, thereby further improving the estimation performance. Simulation results demonstrate that the proposed algorithm can achieve high estimation accuracy especially when the number of antennas at the users is small, and reduce pilot overhead by more than five times compared with the existing benchmark approach. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.05559v1-abstract-full').style.display = 'none'; document.getElementById('2502.05559v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 7 figures, 1 table</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2502.01143">arXiv:2502.01143</a> <span> [<a href="https://arxiv.org/pdf/2502.01143">pdf</a>, <a href="https://arxiv.org/format/2502.01143">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Robotics">cs.RO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Artificial Intelligence">cs.AI</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Machine Learning">cs.LG</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Systems and Control">eess.SY</span> </div> </div> <p class="title is-5 mathjax"> ASAP: Aligning Simulation and Real-World Physics for Learning Agile Humanoid Whole-Body Skills </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=He%2C+T">Tairan He</a>, <a href="/search/eess?searchtype=author&query=Gao%2C+J">Jiawei Gao</a>, <a href="/search/eess?searchtype=author&query=Xiao%2C+W">Wenli Xiao</a>, <a href="/search/eess?searchtype=author&query=Zhang%2C+Y">Yuanhang Zhang</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+Z">Zi Wang</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+J">Jiashun Wang</a>, <a href="/search/eess?searchtype=author&query=Luo%2C+Z">Zhengyi Luo</a>, <a href="/search/eess?searchtype=author&query=He%2C+G">Guanqi He</a>, <a href="/search/eess?searchtype=author&query=Sobanbab%2C+N">Nikhil Sobanbab</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Chaoyi Pan</a>, <a href="/search/eess?searchtype=author&query=Yi%2C+Z">Zeji Yi</a>, <a href="/search/eess?searchtype=author&query=Qu%2C+G">Guannan Qu</a>, <a href="/search/eess?searchtype=author&query=Kitani%2C+K">Kris Kitani</a>, <a href="/search/eess?searchtype=author&query=Hodgins%2C+J">Jessica Hodgins</a>, <a href="/search/eess?searchtype=author&query=Fan%2C+L+%22">Linxi "Jim" Fan</a>, <a href="/search/eess?searchtype=author&query=Zhu%2C+Y">Yuke Zhu</a>, <a href="/search/eess?searchtype=author&query=Liu%2C+C">Changliu Liu</a>, <a href="/search/eess?searchtype=author&query=Shi%2C+G">Guanya Shi</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2502.01143v2-abstract-short" style="display: inline;"> Humanoid robots hold the potential for unparalleled versatility in performing human-like, whole-body skills. However, achieving agile and coordinated whole-body motions remains a significant challenge due to the dynamics mismatch between simulation and the real world. Existing approaches, such as system identification (SysID) and domain randomization (DR) methods, often rely on labor-intensive par… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.01143v2-abstract-full').style.display = 'inline'; document.getElementById('2502.01143v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.01143v2-abstract-full" style="display: none;"> Humanoid robots hold the potential for unparalleled versatility in performing human-like, whole-body skills. However, achieving agile and coordinated whole-body motions remains a significant challenge due to the dynamics mismatch between simulation and the real world. Existing approaches, such as system identification (SysID) and domain randomization (DR) methods, often rely on labor-intensive parameter tuning or result in overly conservative policies that sacrifice agility. In this paper, we present ASAP (Aligning Simulation and Real-World Physics), a two-stage framework designed to tackle the dynamics mismatch and enable agile humanoid whole-body skills. In the first stage, we pre-train motion tracking policies in simulation using retargeted human motion data. In the second stage, we deploy the policies in the real world and collect real-world data to train a delta (residual) action model that compensates for the dynamics mismatch. Then, ASAP fine-tunes pre-trained policies with the delta action model integrated into the simulator to align effectively with real-world dynamics. We evaluate ASAP across three transfer scenarios: IsaacGym to IsaacSim, IsaacGym to Genesis, and IsaacGym to the real-world Unitree G1 humanoid robot. Our approach significantly improves agility and whole-body coordination across various dynamic motions, reducing tracking error compared to SysID, DR, and delta dynamics learning baselines. ASAP enables highly agile motions that were previously difficult to achieve, demonstrating the potential of delta action learning in bridging simulation and real-world dynamics. These results suggest a promising sim-to-real direction for developing more expressive and agile humanoids. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.01143v2-abstract-full').style.display = 'none'; document.getElementById('2502.01143v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Project website: https://agile.human2humanoid.com/</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.10689">arXiv:2501.10689</a> <span> [<a href="https://arxiv.org/pdf/2501.10689">pdf</a>, <a href="https://arxiv.org/format/2501.10689">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Low-Complexity Iterative Precoding Design for Near-field Multiuser Systems With Spatial Non-Stationarity </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Liu%2C+M">Mengyu Liu</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Zhi%2C+K">Kangda Zhi</a>, <a href="/search/eess?searchtype=author&query=Ren%2C+H">Hong Ren</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+C">Cheng-Xiang Wang</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+J">Jiangzhou Wang</a>, <a href="/search/eess?searchtype=author&query=Eldar%2C+Y+C">Yonina C. Eldar</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2501.10689v1-abstract-short" style="display: inline;"> Extremely large antenna arrays (ELAA) are regarded as a promising technology for supporting sixth-generation (6G) networks. However, the large number of antennas significantly increases the computational complexity in precoding design, even for linearly regularized zero-forcing (RZF) precoding. To address this issue, a series of low-complexity iterative precoding are investigated. The main idea of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.10689v1-abstract-full').style.display = 'inline'; document.getElementById('2501.10689v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.10689v1-abstract-full" style="display: none;"> Extremely large antenna arrays (ELAA) are regarded as a promising technology for supporting sixth-generation (6G) networks. However, the large number of antennas significantly increases the computational complexity in precoding design, even for linearly regularized zero-forcing (RZF) precoding. To address this issue, a series of low-complexity iterative precoding are investigated. The main idea of these methods is to avoid matrix inversion of RZF precoding. Specifically, RZF precoding is equivalent to a system of linear equations that can be solved by fast iterative algorithms, such as random Kaczmarz (RK) algorithm. Yet, the performance of RK-based precoding algorithm is limited by the energy distributions of multiple users, which restricts its application in ELAA-assisted systems. To accelerate the RK-based precoding, we introduce the greedy random Kaczmarz (GRK)-based precoding by using the greedy criterion-based selection strategy. To further reduce the complexity of the GRK-based precoding, we propose a visibility region (VR)-based orthogonal GRK (VR-OGRK) precoding that leverages near-field spatial non-stationarity, which is characterized by the concept of VR. Next, by utilizing the information from multiple hyperplanes in each iteration, we extend the GRK-based precoding to the aggregation hyperplane Kaczmarz (AHK)-based pecoding algorithm, which further enhances the convergence rate. Building upon the AHK algorithm, we propose a VR-based orthogonal AHK (VR-OAHK) precoding to further reduce the computational complexity. Furthermore, the proposed iterative precoding algorithms are proven to converge to RZF globally at an exponential rate. Simulation results show that the proposed algorithms achieve faster convergence and lower computational complexity than benchmark algorithms, and yield very similar performance to the RZF precoding. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.10689v1-abstract-full').style.display = 'none'; document.getElementById('2501.10689v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.09234">arXiv:2501.09234</a> <span> [<a href="https://arxiv.org/pdf/2501.09234">pdf</a>, <a href="https://arxiv.org/ps/2501.09234">ps</a>, <a href="https://arxiv.org/format/2501.09234">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Exploring the Advantages of Sparse Arrays in XL-MIMO Systems: Do Half-Wavelength Arrays Still Offer an Edge in the Near Field? </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Chen%2C+X">Xianzhe Chen</a>, <a href="/search/eess?searchtype=author&query=Ren%2C+H">Hong Ren</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+C">Cheng-Xiang Wang</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+J">Jiangzhou Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2501.09234v3-abstract-short" style="display: inline;"> Extremely large-scale multiple-input multiple-output (XL-MIMO) has attracted extensive research attention due to its potential to meet the increasingly demanding requirements of future communication systems. Meanwhile, recent researches have indicated that sparse arrays may offer promising advantages for XL-MIMO systems in the near-field. Motivated by these, this paper investigates a downlink near… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.09234v3-abstract-full').style.display = 'inline'; document.getElementById('2501.09234v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.09234v3-abstract-full" style="display: none;"> Extremely large-scale multiple-input multiple-output (XL-MIMO) has attracted extensive research attention due to its potential to meet the increasingly demanding requirements of future communication systems. Meanwhile, recent researches have indicated that sparse arrays may offer promising advantages for XL-MIMO systems in the near-field. Motivated by these, this paper investigates a downlink near-field XL-MIMO communication system with sparse uniform planar arrays (UPAs). Based on the Green's function-based channel model, the paper focuses on the power distribution of the arrived signal near the focused point of the transmit sparse UPA. In the vicinity of the focused point, along the x-axis and z-axis directions, closed-form expressions for the power distributions are derived. Based on that, expressions for the width and length of the main lobe are obtained in closed form, both of which decrease as the antenna spacing increases. Furthermore, the paper introduces a crucial constraint on system parameters, under which effective degrees-of-freedom (EDoF) of XL-MIMO systems with sparse UPAs can be precisely estimated. Then, the paper proposes an algorithm to obtain a closed-form expression, which can estimate EDoF with high accuracy and low computational complexity. The numerical results verifies the correctness of the main results of this paper. Furthermore, the numerical results reveals the improvement in the performance of XL-MIMO systems with the use of sparse UPAs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.09234v3-abstract-full').style.display = 'none'; document.getElementById('2501.09234v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 1 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 15 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.07062">arXiv:2501.07062</a> <span> [<a href="https://arxiv.org/pdf/2501.07062">pdf</a>, <a href="https://arxiv.org/ps/2501.07062">ps</a>, <a href="https://arxiv.org/format/2501.07062">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Effective DoF-Oriented Optimal Antenna Spacing in Near-Field XL-MIMO Systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Chen%2C+X">Xianzhe Chen</a>, <a href="/search/eess?searchtype=author&query=Ren%2C+H">Hong Ren</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Peng%2C+Z">Zhangjie Peng</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+J">Jiangzhou Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2501.07062v1-abstract-short" style="display: inline;"> This letter investigates the optimal antenna spacing for a near-field XL-MIMO communication system from the perspective of the array gain. Specifically, using the Green's function-based channel model, the letter analyzes the channel capacity, which is related to the effective degrees-of-freedom (EDoF). Then, the letter further investigates the applicability of two EDoF estimation methods. To incre… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.07062v1-abstract-full').style.display = 'inline'; document.getElementById('2501.07062v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.07062v1-abstract-full" style="display: none;"> This letter investigates the optimal antenna spacing for a near-field XL-MIMO communication system from the perspective of the array gain. Specifically, using the Green's function-based channel model, the letter analyzes the channel capacity, which is related to the effective degrees-of-freedom (EDoF). Then, the letter further investigates the applicability of two EDoF estimation methods. To increase EDoF, this letter focuses on analyzing the impact of antenna spacing. Furthermore, from the perspective of the array gain, the letter derives an approximate closed-form expression of the optimal antenna spacing, at which EDoF is maximized and the array gain at the antenna nearest to the focused antenna of the transmit array becomes zero. Finally, numerical results verify the main results of this letter. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.07062v1-abstract-full').style.display = 'none'; document.getElementById('2501.07062v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">The work has been submitted to IEEE Wireless Communications Letters</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.03577">arXiv:2501.03577</a> <span> [<a href="https://arxiv.org/pdf/2501.03577">pdf</a>, <a href="https://arxiv.org/format/2501.03577">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Systems and Control">eess.SY</span> </div> </div> <p class="title is-5 mathjax"> Wireless Channel Measurements and Characterization in Industrial IoT Scenarios </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Zhang%2C+L">Li Zhang</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+C">Cheng-Xiang Wang</a>, <a href="/search/eess?searchtype=author&query=Zhou%2C+Z">Zihao Zhou</a>, <a href="/search/eess?searchtype=author&query=Li%2C+Y">Yuxiao Li</a>, <a href="/search/eess?searchtype=author&query=Huang%2C+J">Jie Huang</a>, <a href="/search/eess?searchtype=author&query=Xin%2C+L">Lijian Xin</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Chun Pan</a>, <a href="/search/eess?searchtype=author&query=Zheng%2C+D">Dabo Zheng</a>, <a href="/search/eess?searchtype=author&query=Wu%2C+X">Xiping Wu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2501.03577v1-abstract-short" style="display: inline;"> Wireless Fidelity (Wi-Fi) communication technologies hold significant potential for realizing the Industrial Internet of Things (IIoT). In this paper, both Single-Input Single-Output (SISO) and polarized Multiple-Input Multiple-Output (MIMO) channel measurements are conducted in an IIoT scenario at the less congested Wi-Fi band, i.e., 5.5~GHz. The purpose is to investigate wireless characteristics… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.03577v1-abstract-full').style.display = 'inline'; document.getElementById('2501.03577v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.03577v1-abstract-full" style="display: none;"> Wireless Fidelity (Wi-Fi) communication technologies hold significant potential for realizing the Industrial Internet of Things (IIoT). In this paper, both Single-Input Single-Output (SISO) and polarized Multiple-Input Multiple-Output (MIMO) channel measurements are conducted in an IIoT scenario at the less congested Wi-Fi band, i.e., 5.5~GHz. The purpose is to investigate wireless characteristics of communications between access points and terminals mounted on automated guided vehicles as well as those surrounding manufacturing areas. For SISO channel measurements, statistical properties including the delay Power Spectral Density (PSD), path loss, shadowing fading, delay spread, excess delay, K-factor, and amplitude distribution of small-scale fading are analyzed and compared with those observed in an office scenario. For MIMO channel measurements, results show that there are multiple Dense Multipath Component (DMC) processes in the delay PSD. An estimation algorithm based on the algorithm for a single DMC process is proposed to effectively process the multi-processes data. Moreover, delay, angular, power, and polarization properties of DMCs are investigated and compared with those of specular multipath components. Furthermore, effects of DMCs on Singular Values (SVs) and channel capacities are explored. Ignoring DMCs can overestimate SVs and underestimate channel capacities. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.03577v1-abstract-full').style.display = 'none'; document.getElementById('2501.03577v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.00909">arXiv:2501.00909</a> <span> [<a href="https://arxiv.org/pdf/2501.00909">pdf</a>, <a href="https://arxiv.org/format/2501.00909">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Information Theory">cs.IT</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> RIS-Aided Integrated Sensing and Communication Systems under Dual-polarized Channels </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Xia%2C+D">Dongnan Xia</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Ren%2C+H">Hong Ren</a>, <a href="/search/eess?searchtype=author&query=Yu%2C+Z">Zhiyuan Yu</a>, <a href="/search/eess?searchtype=author&query=Jin%2C+Y">Yasheng Jin</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+J">Jiangzhou Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2501.00909v1-abstract-short" style="display: inline;"> This paper considers reconfigurable intelligent surface (RIS)-aided integrated sensing and communication (ISAC) systems under dual-polarized (DP) channels. Unlike the existing ISAC systems, which ignored polarization of electromagnetic waves, this study adopts DP base station (BS) and DP RIS to serve users with a pair of DP antennas. The achievable sum rate is maximized through jointly optimiz… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.00909v1-abstract-full').style.display = 'inline'; document.getElementById('2501.00909v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.00909v1-abstract-full" style="display: none;"> This paper considers reconfigurable intelligent surface (RIS)-aided integrated sensing and communication (ISAC) systems under dual-polarized (DP) channels. Unlike the existing ISAC systems, which ignored polarization of electromagnetic waves, this study adopts DP base station (BS) and DP RIS to serve users with a pair of DP antennas. The achievable sum rate is maximized through jointly optimizing the beamforming matrix at the DP BS, and the reflecting coefficients at the DP RIS. To address this problem, we first utilize the weighted minimum mean-square error (WMMSE) method to transform the objective function into a more tractable form, and then an alternating optimization (AO) method is employed to decouple the original problem into two subproblems. Due to the constant modulus constraint, the DP RIS reflection matrix optimization problem is addressed by the majorization-minimization (MM) method. For the DP beamforming matrix, we propose a penalty-based algorithm that can obtain a low-complexity closed-form solution. Simulation results validate the advantage of deploying DP transmit array and DP RIS in the considered ISAC systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.00909v1-abstract-full').style.display = 'none'; document.getElementById('2501.00909v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 1 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2412.20371">arXiv:2412.20371</a> <span> [<a href="https://arxiv.org/pdf/2412.20371">pdf</a>, <a href="https://arxiv.org/format/2412.20371">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Cooperative ISAC-empowered Low-Altitude Economy </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Tang%2C+J">Jun Tang</a>, <a href="/search/eess?searchtype=author&query=Yu%2C+Y">Yiming Yu</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Ren%2C+H">Hong Ren</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+D">Dongming Wang</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+J">Jiangzhou Wang</a>, <a href="/search/eess?searchtype=author&query=You%2C+X">Xiaohu You</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2412.20371v1-abstract-short" style="display: inline;"> This paper proposes a cooperative integrated sensing and communication (ISAC) scheme for the low-altitude sensing scenario, aiming at estimating the parameters of the unmanned aerial vehicles (UAVs) and enhancing the sensing performance via cooperation. The proposed scheme consists of two stages. In Stage I, we formulate the monostatic parameter estimation problem via using a tensor decomposition… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.20371v1-abstract-full').style.display = 'inline'; document.getElementById('2412.20371v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.20371v1-abstract-full" style="display: none;"> This paper proposes a cooperative integrated sensing and communication (ISAC) scheme for the low-altitude sensing scenario, aiming at estimating the parameters of the unmanned aerial vehicles (UAVs) and enhancing the sensing performance via cooperation. The proposed scheme consists of two stages. In Stage I, we formulate the monostatic parameter estimation problem via using a tensor decomposition model. By leveraging the Vandermonde structure of the factor matrix, a spatial smoothing tensor decomposition scheme is introduced to estimate the UAVs' parameters. To further reduce the computational complexity, we design a reduced-dimensional (RD) angle of arrival (AoA) estimation algorithm based on generalized Rayleigh quotient (GRQ). In Stage II, the positions and true velocities of the UAVs are determined through the data fusion across multiple base stations (BSs). Specifically, we first develop a false removing minimum spanning tree (MST)-based data association method to accurately match the BSs' parameter estimations to the same UAV. Then, a Pareto optimality method and a residual weighting scheme are developed to facilitate the position and velocity estimation, respectively. We further extend our approach to the dual-polarized system. Simulation results validate the effectiveness of the proposed schemes in comparison to the conventional techniques. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.20371v1-abstract-full').style.display = 'none'; document.getElementById('2412.20371v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 29 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2412.20349">arXiv:2412.20349</a> <span> [<a href="https://arxiv.org/pdf/2412.20349">pdf</a>, <a href="https://arxiv.org/format/2412.20349">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Two-Timescale Design for AP Mode Selection of Cooperative ISAC Networks </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Ren%2C+Z">Zhichu Ren</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Ren%2C+H">Hong Ren</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+D">Dongming Wang</a>, <a href="/search/eess?searchtype=author&query=Xu%2C+L">Lexi Xu</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+J">Jiangzhou Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2412.20349v1-abstract-short" style="display: inline;"> As an emerging technology, cooperative bi-static integrated sensing and communication (ISAC) is promising to achieve high-precision sensing, high-rate communication as well as self-interference (SI) avoidance. This paper investigates the two-timescale design for access point (AP) mode selection to realize the full potential of the cooperative bi-static ISAC network with low system overhead, where… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.20349v1-abstract-full').style.display = 'inline'; document.getElementById('2412.20349v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.20349v1-abstract-full" style="display: none;"> As an emerging technology, cooperative bi-static integrated sensing and communication (ISAC) is promising to achieve high-precision sensing, high-rate communication as well as self-interference (SI) avoidance. This paper investigates the two-timescale design for access point (AP) mode selection to realize the full potential of the cooperative bi-static ISAC network with low system overhead, where the beamforming at the APs is adapted to the rapidly-changing instantaneous channel state information (CSI), while the AP mode is adapted to the slowly-changing statistical CSI. We first apply the minimum mean square error (MMSE) estimator to estimate the channel between the APs and the channels from the APs to the user equipments (UEs). Then we adopt the low-complexity maximum ratio transmission (MRT) beamforming and the maximum ratio combining (MRC) detector, and derive the closed-form expressions of the communication rate and the sensing signal-to-interference-plus-noise-ratio (SINR). We formulate a non-convex integer optimization problem to maximize the minimum sensing SINR under the communication quality of service (QoS) constraints. McCormick envelope relaxation and successive convex approximation (SCA) techniques are applied to solve the challenging non-convex integer optimization problem. Simulation results validate the closed-form expressions and prove the convergence and effectiveness of the proposed AP mode selection scheme. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.20349v1-abstract-full').style.display = 'none'; document.getElementById('2412.20349v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 8 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2412.15843">arXiv:2412.15843</a> <span> [<a href="https://arxiv.org/pdf/2412.15843">pdf</a>, <a href="https://arxiv.org/format/2412.15843">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Rethinking Hardware Impairments in Multi-User Systems: Can FAS Make a Difference? </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Yao%2C+J">Junteng Yao</a>, <a href="/search/eess?searchtype=author&query=Wu%2C+T">Tuo Wu</a>, <a href="/search/eess?searchtype=author&query=Zhou%2C+L">Liaoshi Zhou</a>, <a href="/search/eess?searchtype=author&query=Jin%2C+M">Ming Jin</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Elkashlan%2C+M">Maged Elkashlan</a>, <a href="/search/eess?searchtype=author&query=Adachi%2C+F">Fumiyuki Adachi</a>, <a href="/search/eess?searchtype=author&query=Karagiannidis%2C+G+K">George K. Karagiannidis</a>, <a href="/search/eess?searchtype=author&query=Al-Dhahir%2C+N">Naofal Al-Dhahir</a>, <a href="/search/eess?searchtype=author&query=Yuen%2C+C">Chau Yuen</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2412.15843v1-abstract-short" style="display: inline;"> In this paper, we analyze the role of fluid antenna systems (FAS) in multi-user systems with hardware impairments (HIs). Specifically, we investigate a scenario where a base station (BS) equipped with multiple fluid antennas communicates with multiple users (CUs), each equipped with a single fluid antenna. Our objective is to maximize the minimum communication rate among all users by jointly optim… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.15843v1-abstract-full').style.display = 'inline'; document.getElementById('2412.15843v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.15843v1-abstract-full" style="display: none;"> In this paper, we analyze the role of fluid antenna systems (FAS) in multi-user systems with hardware impairments (HIs). Specifically, we investigate a scenario where a base station (BS) equipped with multiple fluid antennas communicates with multiple users (CUs), each equipped with a single fluid antenna. Our objective is to maximize the minimum communication rate among all users by jointly optimizing the BS's transmit beamforming, the positions of its transmit fluid antennas, and the positions of the CUs' receive fluid antennas. To address this non-convex problem, we propose a block coordinate descent (BCD) algorithm integrating semidefinite relaxation (SDR), rank-one constraint relaxation (SRCR), successive convex approximation (SCA), and majorization-minimization (MM). Simulation results demonstrate that FAS significantly enhances system performance and robustness, with notable gains when both the BS and CUs are equipped with fluid antennas. Even under low transmit power conditions, deploying FAS at the BS alone yields substantial performance gains. However, the effectiveness of FAS depends on the availability of sufficient movement space, as space constraints may limit its benefits compared to fixed antenna strategies. Our findings highlight the potential of FAS to mitigate HIs and enhance multi-user system performance, while emphasizing the need for practical deployment considerations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.15843v1-abstract-full').style.display = 'none'; document.getElementById('2412.15843v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.06983">arXiv:2411.06983</a> <span> [<a href="https://arxiv.org/pdf/2411.06983">pdf</a>, <a href="https://arxiv.org/format/2411.06983">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Sensing Capacity for Integrated Sensing and Communication Systems in Low-Altitude Economy </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Wan%2C+J">Jiahua Wan</a>, <a href="/search/eess?searchtype=author&query=Ren%2C+H">Hong Ren</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Zhang%2C+Z">Zhenkun Zhang</a>, <a href="/search/eess?searchtype=author&query=Gao%2C+S">Songtao Gao</a>, <a href="/search/eess?searchtype=author&query=Yu%2C+Y">Yiming Yu</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+C">Chengzhong Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2411.06983v1-abstract-short" style="display: inline;"> The burgeoning significance of the low-altitude economy (LAE) has garnered considerable interest, largely fuelled by the widespread deployment of unmanned aerial vehicles (UAVs). To tackle the challenges associated with the detection of unauthorized UAVs and the efficient scheduling of authorized UAVs, this letter introduces a novel performance metric, termed sensing capacity, for integrated sensi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.06983v1-abstract-full').style.display = 'inline'; document.getElementById('2411.06983v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.06983v1-abstract-full" style="display: none;"> The burgeoning significance of the low-altitude economy (LAE) has garnered considerable interest, largely fuelled by the widespread deployment of unmanned aerial vehicles (UAVs). To tackle the challenges associated with the detection of unauthorized UAVs and the efficient scheduling of authorized UAVs, this letter introduces a novel performance metric, termed sensing capacity, for integrated sensing and communication (ISAC) systems. This metric, which quantifies the capability of a base station (BS) to detect multiple UAVs simultaneously, leverages signal-to-noise ratio (SNR) and probability of detection (PD) as key intermediate variables. Through mathematical derivations, we can derive a closed-form solution for the maximum number of UAVs that can be detected by the BS while adhering to a specific SNR constraint. Furthermore, an approximate solution based on PD constraints is proposed to facilitate the efficient determination of the threshold for the maximum number of detectable UAVs. The accuracy of this analytical approach is verified through extensive simulation results. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.06983v1-abstract-full').style.display = 'none'; document.getElementById('2411.06983v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.04709">arXiv:2410.04709</a> <span> [<a href="https://arxiv.org/pdf/2410.04709">pdf</a>, <a href="https://arxiv.org/format/2410.04709">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Direction Modulation Design for UAV Assisted by IRS with discrete phase shift </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Li%2C+M">Maolin Li</a>, <a href="/search/eess?searchtype=author&query=Gao%2C+W">Wei Gao</a>, <a href="/search/eess?searchtype=author&query=Wu%2C+Q">Qi Wu</a>, <a href="/search/eess?searchtype=author&query=Shu%2C+F">Feng Shu</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Wu%2C+D">Di Wu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2410.04709v1-abstract-short" style="display: inline;"> As a physical layer security technology, directional modulation (DM) can be combined with intelligent reflect-ing surface (IRS) to improve the security of drone communications. In this paper, a directional modulation scheme assisted by the IRS is proposed to maximize the transmission rate of unmanned aerial vehicle (UAV) secure communication. Specifically, with the assistance of the IRS, the UAV t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.04709v1-abstract-full').style.display = 'inline'; document.getElementById('2410.04709v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.04709v1-abstract-full" style="display: none;"> As a physical layer security technology, directional modulation (DM) can be combined with intelligent reflect-ing surface (IRS) to improve the security of drone communications. In this paper, a directional modulation scheme assisted by the IRS is proposed to maximize the transmission rate of unmanned aerial vehicle (UAV) secure communication. Specifically, with the assistance of the IRS, the UAV transmits legitimate information and main-tains its constellation pattern at the location of legitimate users on the ground, while the constellation pattern is disrupted at the eavesdropper's location. In order to solve the joint optimization problem of digital weight coefficients, UAV position, and IRS discrete phase shift, firstly, the digital weight vector and UAV position are optimized through power minimization. Secondly, three methods are proposed to optimize IRS phase shift, namely vector trajectory (VT) method, cross entropy vector trajectory (CE-VT) algorithm, and block coordinate descent vector trajectory (BCD-VT) algorithm. Compared to traditional cross entropy (CE) methods and block coordinate descent (BCD) methods, the proposed CE-VT and BCD-VT algorithms can improve transmission rate performance. The numerical results validate the effectiveness of the optimization scheme in IRS assisted UAV communication. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.04709v1-abstract-full').style.display = 'none'; document.getElementById('2410.04709v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.15977">arXiv:2409.15977</a> <span> [<a href="https://arxiv.org/pdf/2409.15977">pdf</a>, <a href="https://arxiv.org/format/2409.15977">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Audio and Speech Processing">eess.AS</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Computation and Language">cs.CL</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Sound">cs.SD</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.18653/v1/2024.emnlp-main.117">10.18653/v1/2024.emnlp-main.117 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> TCSinger: Zero-Shot Singing Voice Synthesis with Style Transfer and Multi-Level Style Control </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Zhang%2C+Y">Yu Zhang</a>, <a href="/search/eess?searchtype=author&query=Jiang%2C+Z">Ziyue Jiang</a>, <a href="/search/eess?searchtype=author&query=Li%2C+R">Ruiqi Li</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Changhao Pan</a>, <a href="/search/eess?searchtype=author&query=He%2C+J">Jinzheng He</a>, <a href="/search/eess?searchtype=author&query=Huang%2C+R">Rongjie Huang</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+C">Chuxin Wang</a>, <a href="/search/eess?searchtype=author&query=Zhao%2C+Z">Zhou Zhao</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2409.15977v4-abstract-short" style="display: inline;"> Zero-shot singing voice synthesis (SVS) with style transfer and style control aims to generate high-quality singing voices with unseen timbres and styles (including singing method, emotion, rhythm, technique, and pronunciation) from audio and text prompts. However, the multifaceted nature of singing styles poses a significant challenge for effective modeling, transfer, and control. Furthermore, cu… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.15977v4-abstract-full').style.display = 'inline'; document.getElementById('2409.15977v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.15977v4-abstract-full" style="display: none;"> Zero-shot singing voice synthesis (SVS) with style transfer and style control aims to generate high-quality singing voices with unseen timbres and styles (including singing method, emotion, rhythm, technique, and pronunciation) from audio and text prompts. However, the multifaceted nature of singing styles poses a significant challenge for effective modeling, transfer, and control. Furthermore, current SVS models often fail to generate singing voices rich in stylistic nuances for unseen singers. To address these challenges, we introduce TCSinger, the first zero-shot SVS model for style transfer across cross-lingual speech and singing styles, along with multi-level style control. Specifically, TCSinger proposes three primary modules: 1) the clustering style encoder employs a clustering vector quantization model to stably condense style information into a compact latent space; 2) the Style and Duration Language Model (S\&D-LM) concurrently predicts style information and phoneme duration, which benefits both; 3) the style adaptive decoder uses a novel mel-style adaptive normalization method to generate singing voices with enhanced details. Experimental results show that TCSinger outperforms all baseline models in synthesis quality, singer similarity, and style controllability across various tasks, including zero-shot style transfer, multi-level style control, cross-lingual style transfer, and speech-to-singing style transfer. Singing voice samples can be accessed at https://aaronz345.github.io/TCSingerDemo/. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.15977v4-abstract-full').style.display = 'none'; document.getElementById('2409.15977v4-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 24 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted by EMNLP 2024</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing, pages 1960-1975 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.13832">arXiv:2409.13832</a> <span> [<a href="https://arxiv.org/pdf/2409.13832">pdf</a>, <a href="https://arxiv.org/format/2409.13832">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Audio and Speech Processing">eess.AS</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Computation and Language">cs.CL</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Sound">cs.SD</span> </div> </div> <p class="title is-5 mathjax"> GTSinger: A Global Multi-Technique Singing Corpus with Realistic Music Scores for All Singing Tasks </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Zhang%2C+Y">Yu Zhang</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Changhao Pan</a>, <a href="/search/eess?searchtype=author&query=Guo%2C+W">Wenxiang Guo</a>, <a href="/search/eess?searchtype=author&query=Li%2C+R">Ruiqi Li</a>, <a href="/search/eess?searchtype=author&query=Zhu%2C+Z">Zhiyuan Zhu</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+J">Jialei Wang</a>, <a href="/search/eess?searchtype=author&query=Xu%2C+W">Wenhao Xu</a>, <a href="/search/eess?searchtype=author&query=Lu%2C+J">Jingyu Lu</a>, <a href="/search/eess?searchtype=author&query=Hong%2C+Z">Zhiqing Hong</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+C">Chuxin Wang</a>, <a href="/search/eess?searchtype=author&query=Zhang%2C+L">LiChao Zhang</a>, <a href="/search/eess?searchtype=author&query=He%2C+J">Jinzheng He</a>, <a href="/search/eess?searchtype=author&query=Jiang%2C+Z">Ziyue Jiang</a>, <a href="/search/eess?searchtype=author&query=Chen%2C+Y">Yuxin Chen</a>, <a href="/search/eess?searchtype=author&query=Yang%2C+C">Chen Yang</a>, <a href="/search/eess?searchtype=author&query=Zhou%2C+J">Jiecheng Zhou</a>, <a href="/search/eess?searchtype=author&query=Cheng%2C+X">Xinyu Cheng</a>, <a href="/search/eess?searchtype=author&query=Zhao%2C+Z">Zhou Zhao</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2409.13832v5-abstract-short" style="display: inline;"> The scarcity of high-quality and multi-task singing datasets significantly hinders the development of diverse controllable and personalized singing tasks, as existing singing datasets suffer from low quality, limited diversity of languages and singers, absence of multi-technique information and realistic music scores, and poor task suitability. To tackle these problems, we present GTSinger, a larg… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.13832v5-abstract-full').style.display = 'inline'; document.getElementById('2409.13832v5-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.13832v5-abstract-full" style="display: none;"> The scarcity of high-quality and multi-task singing datasets significantly hinders the development of diverse controllable and personalized singing tasks, as existing singing datasets suffer from low quality, limited diversity of languages and singers, absence of multi-technique information and realistic music scores, and poor task suitability. To tackle these problems, we present GTSinger, a large global, multi-technique, free-to-use, high-quality singing corpus with realistic music scores, designed for all singing tasks, along with its benchmarks. Particularly, (1) we collect 80.59 hours of high-quality singing voices, forming the largest recorded singing dataset; (2) 20 professional singers across nine widely spoken languages offer diverse timbres and styles; (3) we provide controlled comparison and phoneme-level annotations of six commonly used singing techniques, helping technique modeling and control; (4) GTSinger offers realistic music scores, assisting real-world musical composition; (5) singing voices are accompanied by manual phoneme-to-audio alignments, global style labels, and 16.16 hours of paired speech for various singing tasks. Moreover, to facilitate the use of GTSinger, we conduct four benchmark experiments: technique-controllable singing voice synthesis, technique recognition, style transfer, and speech-to-singing conversion. The corpus and demos can be found at http://aaronz345.github.io/GTSingerDemo/. We provide the dataset and the code for processing data and conducting benchmarks at https://huggingface.co/datasets/GTSinger/GTSinger and https://github.com/AaronZ345/GTSinger. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.13832v5-abstract-full').style.display = 'none'; document.getElementById('2409.13832v5-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 20 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted by NeurIPS 2024 (Spotlight)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.03005">arXiv:2409.03005</a> <span> [<a href="https://arxiv.org/pdf/2409.03005">pdf</a>, <a href="https://arxiv.org/format/2409.03005">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Robotics">cs.RO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Machine Learning">cs.LG</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Systems and Control">eess.SY</span> </div> </div> <p class="title is-5 mathjax"> PIETRA: Physics-Informed Evidential Learning for Traversing Out-of-Distribution Terrain </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Cai%2C+X">Xiaoyi Cai</a>, <a href="/search/eess?searchtype=author&query=Queeney%2C+J">James Queeney</a>, <a href="/search/eess?searchtype=author&query=Xu%2C+T">Tong Xu</a>, <a href="/search/eess?searchtype=author&query=Datar%2C+A">Aniket Datar</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Chenhui Pan</a>, <a href="/search/eess?searchtype=author&query=Miller%2C+M">Max Miller</a>, <a href="/search/eess?searchtype=author&query=Flather%2C+A">Ashton Flather</a>, <a href="/search/eess?searchtype=author&query=Osteen%2C+P+R">Philip R. Osteen</a>, <a href="/search/eess?searchtype=author&query=Roy%2C+N">Nicholas Roy</a>, <a href="/search/eess?searchtype=author&query=Xiao%2C+X">Xuesu Xiao</a>, <a href="/search/eess?searchtype=author&query=How%2C+J+P">Jonathan P. How</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2409.03005v2-abstract-short" style="display: inline;"> Self-supervised learning is a powerful approach for developing traversability models for off-road navigation, but these models often struggle with inputs unseen during training. Existing methods utilize techniques like evidential deep learning to quantify model uncertainty, helping to identify and avoid out-of-distribution terrain. However, always avoiding out-of-distribution terrain can be overly… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.03005v2-abstract-full').style.display = 'inline'; document.getElementById('2409.03005v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.03005v2-abstract-full" style="display: none;"> Self-supervised learning is a powerful approach for developing traversability models for off-road navigation, but these models often struggle with inputs unseen during training. Existing methods utilize techniques like evidential deep learning to quantify model uncertainty, helping to identify and avoid out-of-distribution terrain. However, always avoiding out-of-distribution terrain can be overly conservative, e.g., when novel terrain can be effectively analyzed using a physics-based model. To overcome this challenge, we introduce Physics-Informed Evidential Traversability (PIETRA), a self-supervised learning framework that integrates physics priors directly into the mathematical formulation of evidential neural networks and introduces physics knowledge implicitly through an uncertainty-aware, physics-informed training loss. Our evidential network seamlessly transitions between learned and physics-based predictions for out-of-distribution inputs. Additionally, the physics-informed loss regularizes the learned model, ensuring better alignment with the physics model. Extensive simulations and hardware experiments demonstrate that PIETRA improves both learning accuracy and navigation performance in environments with significant distribution shifts. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.03005v2-abstract-full').style.display = 'none'; document.getElementById('2409.03005v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 4 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">To appear in RA-L. Video: https://youtu.be/OTnNZ96oJRk</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.16455">arXiv:2408.16455</a> <span> [<a href="https://arxiv.org/pdf/2408.16455">pdf</a>, <a href="https://arxiv.org/format/2408.16455">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Information Theory">cs.IT</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Addressing the Mutual Interference in Uplink ISAC Receivers: A Projection Method </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Yu%2C+Z">Zhiyuan Yu</a>, <a href="/search/eess?searchtype=author&query=Ren%2C+H">Hong Ren</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Zhou%2C+G">Gui Zhou</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+R">Ruizhe Wang</a>, <a href="/search/eess?searchtype=author&query=Liu%2C+M">Mengyu Liu</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+J">Jiangzhou Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2408.16455v1-abstract-short" style="display: inline;"> Dual function radar and communication (DFRC) is a promising research direction within integrated sensing and communication (ISAC), improving hardware and spectrum efficiency by merging sensing and communication (S&C) functionalities into a shared platform. However, the DFRC receiver (DFRC-R) is tasked with both uplink communication signal detection and simultaneously target-related parameter estim… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.16455v1-abstract-full').style.display = 'inline'; document.getElementById('2408.16455v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.16455v1-abstract-full" style="display: none;"> Dual function radar and communication (DFRC) is a promising research direction within integrated sensing and communication (ISAC), improving hardware and spectrum efficiency by merging sensing and communication (S&C) functionalities into a shared platform. However, the DFRC receiver (DFRC-R) is tasked with both uplink communication signal detection and simultaneously target-related parameter estimation from the echoes, leading to issues with mutual interference. In this paper, a projection-based scheme is proposed to equivalently transform the joint signal detection and target estimation problem into a joint signal detection process across multiple snapshots. Compared with conventional successive interference cancellation (SIC) schemes, our proposed approach achieves a higher signal-to-noise ratio (SNR), and a higher ergodic rate when the radar signal is non-negligible. Nonetheless, it introduces an ill-conditioned signal detection problem, which is addressed using a non-linear detector. By jointly processing an increased number of snapshots, the proposed scheme can achieve high S&C performance simultaneously. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.16455v1-abstract-full').style.display = 'none'; document.getElementById('2408.16455v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 29 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5 pages, 3 figures, accepted by IEEE WCL</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.08141">arXiv:2407.08141</a> <span> [<a href="https://arxiv.org/pdf/2407.08141">pdf</a>, <a href="https://arxiv.org/ps/2407.08141">ps</a>, <a href="https://arxiv.org/format/2407.08141">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> A Framework of FAS-RIS Systems: Performance Analysis and Throughput Optimization </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Yao%2C+J">Junteng Yao</a>, <a href="/search/eess?searchtype=author&query=Lai%2C+X">Xiazhi Lai</a>, <a href="/search/eess?searchtype=author&query=Zhi%2C+K">Kangda Zhi</a>, <a href="/search/eess?searchtype=author&query=Wu%2C+T">Tuo Wu</a>, <a href="/search/eess?searchtype=author&query=Jin%2C+M">Ming Jin</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Elkashlan%2C+M">Maged Elkashlan</a>, <a href="/search/eess?searchtype=author&query=Yuen%2C+C">Chau Yuen</a>, <a href="/search/eess?searchtype=author&query=Wong%2C+K">Kai-Kit Wong</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2407.08141v1-abstract-short" style="display: inline;"> In this paper, we investigate reconfigurable intelligent surface (RIS)-assisted communication systems which involve a fixed-antenna base station (BS) and a mobile user (MU) that is equipped with fluid antenna system (FAS). Specifically, the RIS is utilized to enable communication for the user whose direct link from the base station is blocked by obstacles. We propose a comprehensive framework that… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.08141v1-abstract-full').style.display = 'inline'; document.getElementById('2407.08141v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.08141v1-abstract-full" style="display: none;"> In this paper, we investigate reconfigurable intelligent surface (RIS)-assisted communication systems which involve a fixed-antenna base station (BS) and a mobile user (MU) that is equipped with fluid antenna system (FAS). Specifically, the RIS is utilized to enable communication for the user whose direct link from the base station is blocked by obstacles. We propose a comprehensive framework that provides transmission design for both static scenarios with the knowledge of channel state information (CSI) and harsh environments where CSI is hard to acquire. It leads to two approaches: a CSI-based scheme where CSI is available, and a CSI-free scheme when CSI is inaccessible. Given the complex spatial correlations in FAS, we employ block-diagonal matrix approximation and independent antenna equivalent models to simplify the derivation of outage probabilities in both cases. Based on the derived outage probabilities, we then optimize the throughput of the FAS-RIS system. For the CSI-based scheme, we first propose a gradient ascent-based algorithm to obtain a near-optimal solution. Then, to address the possible high computational complexity in the gradient algorithm, we approximate the objective function and confirm a unique optimal solution accessible through a bisection search method. For the CSI-free scheme, we apply the partial gradient ascent algorithm, reducing complexity further than full gradient algorithms. We also approximate the objective function and derive a locally optimal closed-form solution to maximize throughput. Simulation results validate the effectiveness of the proposed framework for the transmission design in FAS-RIS systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.08141v1-abstract-full').style.display = 'none'; document.getElementById('2407.08141v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">submitted to IEEE journal for possible publication</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.03228">arXiv:2407.03228</a> <span> [<a href="https://arxiv.org/pdf/2407.03228">pdf</a>, <a href="https://arxiv.org/format/2407.03228">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Movable Antenna-enabled RIS-aided Integrated Sensing and Communication </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Wu%2C+H">Haisu Wu</a>, <a href="/search/eess?searchtype=author&query=Ren%2C+H">Hong Ren</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Zhang%2C+Y">Yang Zhang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2407.03228v2-abstract-short" style="display: inline;"> In this paper, we investigate a movable antenna (MA)-aided integrated sensing and communication (ISAC) system, where a reconfigurable intelligent surface (RIS) is employed to enhance wireless communication and sensing performance in dead zones. Specifically, this paper aims to maximize the minimum beampattern gain at the RIS by jointly optimizing beamforming matrix at the base station (BS), the re… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.03228v2-abstract-full').style.display = 'inline'; document.getElementById('2407.03228v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.03228v2-abstract-full" style="display: none;"> In this paper, we investigate a movable antenna (MA)-aided integrated sensing and communication (ISAC) system, where a reconfigurable intelligent surface (RIS) is employed to enhance wireless communication and sensing performance in dead zones. Specifically, this paper aims to maximize the minimum beampattern gain at the RIS by jointly optimizing beamforming matrix at the base station (BS), the reflecting coefficients at the RIS and the positions of the MAs, subject to signal-to-interference-plus-noise ratio (SINR) constraint for the users and maximum transmit power at the BS. To tackle this non-convex optimization problem, we propose an alternating optimization (AO) algorithm and employ semidefinite relaxation (SDR), sequential rank-one constraint relaxation (SRCR) and successive convex approximation (SCA) techniques. Numerical results indicate that the MA and RIS-aided ISAC system outperforms conventional fixed position antenna (FPA) and RIS-aided systems. In addition, the application of MAs can reduce the similarity of user channels and enhance channel gain in the ISAC system. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.03228v2-abstract-full').style.display = 'none'; document.getElementById('2407.03228v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">14 pages, 11 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.01573">arXiv:2407.01573</a> <span> [<a href="https://arxiv.org/pdf/2407.01573">pdf</a>, <a href="https://arxiv.org/format/2407.01573">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Robotics">cs.RO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Machine Learning">cs.LG</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Systems and Control">eess.SY</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optimization and Control">math.OC</span> </div> </div> <p class="title is-5 mathjax"> Model-Based Diffusion for Trajectory Optimization </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Pan%2C+C">Chaoyi Pan</a>, <a href="/search/eess?searchtype=author&query=Yi%2C+Z">Zeji Yi</a>, <a href="/search/eess?searchtype=author&query=Shi%2C+G">Guanya Shi</a>, <a href="/search/eess?searchtype=author&query=Qu%2C+G">Guannan Qu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2407.01573v1-abstract-short" style="display: inline;"> Recent advances in diffusion models have demonstrated their strong capabilities in generating high-fidelity samples from complex distributions through an iterative refinement process. Despite the empirical success of diffusion models in motion planning and control, the model-free nature of these methods does not leverage readily available model information and limits their generalization to new sc… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.01573v1-abstract-full').style.display = 'inline'; document.getElementById('2407.01573v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.01573v1-abstract-full" style="display: none;"> Recent advances in diffusion models have demonstrated their strong capabilities in generating high-fidelity samples from complex distributions through an iterative refinement process. Despite the empirical success of diffusion models in motion planning and control, the model-free nature of these methods does not leverage readily available model information and limits their generalization to new scenarios beyond the training data (e.g., new robots with different dynamics). In this work, we introduce Model-Based Diffusion (MBD), an optimization approach using the diffusion process to solve trajectory optimization (TO) problems without data. The key idea is to explicitly compute the score function by leveraging the model information in TO problems, which is why we refer to our approach as model-based diffusion. Moreover, although MBD does not require external data, it can be naturally integrated with data of diverse qualities to steer the diffusion process. We also reveal that MBD has interesting connections to sampling-based optimization. Empirical evaluations show that MBD outperforms state-of-the-art reinforcement learning and sampling-based TO methods in challenging contact-rich tasks. Additionally, MBD's ability to integrate with data enhances its versatility and practical applicability, even with imperfect and infeasible data (e.g., partial-state demonstrations for high-dimensional humanoids), beyond the scope of standard diffusion models. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.01573v1-abstract-full').style.display = 'none'; document.getElementById('2407.01573v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Website: https://lecar-lab.github.io/mbd/</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.00042">arXiv:2407.00042</a> <span> [<a href="https://arxiv.org/pdf/2407.00042">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Neurons and Cognition">q-bio.NC</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Social and Information Networks">cs.SI</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Systems and Control">eess.SY</span> </div> </div> <p class="title is-5 mathjax"> Module control of network analysis in psychopathology </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Pan%2C+C">Chunyu Pan</a>, <a href="/search/eess?searchtype=author&query=Zhang%2C+Q">Quan Zhang</a>, <a href="/search/eess?searchtype=author&query=Zhu%2C+Y">Yue Zhu</a>, <a href="/search/eess?searchtype=author&query=Kong%2C+S">Shengzhou Kong</a>, <a href="/search/eess?searchtype=author&query=Liu%2C+J">Juan Liu</a>, <a href="/search/eess?searchtype=author&query=Zhang%2C+C">Changsheng Zhang</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+F">Fei Wang</a>, <a href="/search/eess?searchtype=author&query=Zhang%2C+X">Xizhe Zhang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2407.00042v1-abstract-short" style="display: inline;"> The network approach to characterizing psychopathology departs from traditional latent categorical and dimensional approaches. Causal interplay among symptoms contributed to dynamic psychopathology system. Therefore, analyzing the symptom clusters is critical for understanding mental disorders. Furthermore, despite extensive research studying the topological features of symptom networks, the contr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.00042v1-abstract-full').style.display = 'inline'; document.getElementById('2407.00042v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.00042v1-abstract-full" style="display: none;"> The network approach to characterizing psychopathology departs from traditional latent categorical and dimensional approaches. Causal interplay among symptoms contributed to dynamic psychopathology system. Therefore, analyzing the symptom clusters is critical for understanding mental disorders. Furthermore, despite extensive research studying the topological features of symptom networks, the control relationships between symptoms remain largely unclear. Here, we present a novel systematizing concept, module control, to analyze the control principle of the symptom network at a module level. We introduce Module Control Network (MCN) to identify key modules that regulate the network's behavior. By applying our approach to a multivariate psychological dataset, we discover that non-emotional modules, such as sleep-related and stress-related modules, are the primary controlling modules in the symptom network. Our findings indicate that module control can expose central symptom cluster governing psychopathology network, offering novel insights into the underlying mechanisms of mental disorders and individualized approach to psychological interventions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.00042v1-abstract-full').style.display = 'none'; document.getElementById('2407.00042v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2406.16876">arXiv:2406.16876</a> <span> [<a href="https://arxiv.org/pdf/2406.16876">pdf</a>, <a href="https://arxiv.org/format/2406.16876">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Near-Field Mobile Tracking: A Framework of Using XL-RIS Information </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Wu%2C+T">Tuo Wu</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Zhi%2C+K">Kangda Zhi</a>, <a href="/search/eess?searchtype=author&query=Yao%2C+J">Junteng Yao</a>, <a href="/search/eess?searchtype=author&query=Ren%2C+H">Hong Ren</a>, <a href="/search/eess?searchtype=author&query=Elkashlan%2C+M">Maged Elkashlan</a>, <a href="/search/eess?searchtype=author&query=Yuen%2C+C">Chau Yuen</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2406.16876v2-abstract-short" style="display: inline;"> This paper introduces a novel mobile tracking framework leveraging the high-dimensional signal received from extremely large-scale (XL) reconfigurable intelligent surfaces (RIS). This received signal, named XL-RIS information, has a much larger data dimension and therefore offers a richer feature set compared to the traditional base station (BS) received signal, i.e., BS information, enabling more… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.16876v2-abstract-full').style.display = 'inline'; document.getElementById('2406.16876v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.16876v2-abstract-full" style="display: none;"> This paper introduces a novel mobile tracking framework leveraging the high-dimensional signal received from extremely large-scale (XL) reconfigurable intelligent surfaces (RIS). This received signal, named XL-RIS information, has a much larger data dimension and therefore offers a richer feature set compared to the traditional base station (BS) received signal, i.e., BS information, enabling more accurate tracking of mobile users (MUs). As the first step, we present an XL-RIS information reconstruction (XL-RIS-IR) algorithm to reconstruct the high-dimensional XL-RIS information from the low-dimensional BS information. Building on this, this paper proposes a comprehensive framework for mobile tracking, consisting of a Feature Extraction Module and a Mobile Tracking Module. The Feature Extraction Module incorporates a convolutional neural network (CNN) extractor for spatial features, a time and frequency (T$\&$F) extractor for domain features, and a near-field angles of arrival (AoAs) extractor for capturing AoA features within the XL-RIS. These features are combined into a comprehensive feature vector, forming a time-varying sequence fed into the Mobile Tracking Module, which employs an Auto-encoder (AE) with a stacked bidirectional long short-term memory (Bi-LSTM) encoder and a standard LSTM decoder to predict MUs' positions in the upcoming time slot. Simulation results confirm that the tracking accuracy of our proposed framework is significantly enhanced by using reconstructed XL-RIS information and exhibits substantial robustness to signal-to-noise ratio (SNR) variations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.16876v2-abstract-full').style.display = 'none'; document.getElementById('2406.16876v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2406.09695">arXiv:2406.09695</a> <span> [<a href="https://arxiv.org/pdf/2406.09695">pdf</a>, <a href="https://arxiv.org/format/2406.09695">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Machine Learning-based Near-field Emitter Location Sensing via Grouped Hybrid Analog and Digital XL-MIMO Receive Array </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Li%2C+Y">Yifan Li</a>, <a href="/search/eess?searchtype=author&query=Shu%2C+F">Feng Shu</a>, <a href="/search/eess?searchtype=author&query=Wei%2C+K">Kang Wei</a>, <a href="/search/eess?searchtype=author&query=Bai%2C+J">Jiatong Bai</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Wu%2C+Y">Yongpeng Wu</a>, <a href="/search/eess?searchtype=author&query=Song%2C+Y">Yaoliang Song</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+J">Jiangzhou Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2406.09695v2-abstract-short" style="display: inline;"> As a green MIMO structure, the partially-connected hybrid analog and digital (PC-HAD) structure has been widely used in the far-field (FF) scenario for it can significantly reduce the hardware cost and complexity of large-scale or extremely large-scale MIMO (XL-MIMO) array. Recently, near-field (NF) emitter localization including direction-of-arrival (DOA) and range estimations has drawn a lot of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.09695v2-abstract-full').style.display = 'inline'; document.getElementById('2406.09695v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.09695v2-abstract-full" style="display: none;"> As a green MIMO structure, the partially-connected hybrid analog and digital (PC-HAD) structure has been widely used in the far-field (FF) scenario for it can significantly reduce the hardware cost and complexity of large-scale or extremely large-scale MIMO (XL-MIMO) array. Recently, near-field (NF) emitter localization including direction-of-arrival (DOA) and range estimations has drawn a lot of attention, but is rarely explored via PC-HAD structure. In this paper, we first analyze the impact of PC-HAD structure on the NF emitter localization and observe that the phase ambiguity (PA) problem caused by PC-HAD structure can be removed inherently with low-latency in the NF scenario. To obtain the exact NF DOA estimation results, we propose a grouped PC-HAD structure, which is capable of dividing the NF DOA estimation problem into multiple FF DOA estimation problems via partitioning the large-scale PC-HAD array into small-scale groups. An angle calibration method is developed to address the inconsistency among these FF DOA estimation problems. Then, to eliminate PA and improve the NF emitter localization performance, we develop three machine learning (ML)-based methods, i.e., two low-complexity data-driven clustering-based methods and one model-driven regression method, namely RegNet. Furthermore, the Cramer-Rao lower bound (CRLB) of NF emitter localization for the proposed grouped PC-HAD structure is derived and reveals that localization performance will decrease with the increasing of the number of groups. The simulation results show that the proposed methods can achieve CRLB at different SNR regions, the RegNet has great performance advantages at low SNR regions and the clustering-based methods have much lower computation complexity. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.09695v2-abstract-full').style.display = 'none'; document.getElementById('2406.09695v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 3 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 13 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.18775">arXiv:2405.18775</a> <span> [<a href="https://arxiv.org/pdf/2405.18775">pdf</a>, <a href="https://arxiv.org/format/2405.18775">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Novel Synchronization Scheme for Cooperative ISAC Systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Peng%2C+Q">Qihao Peng</a>, <a href="/search/eess?searchtype=author&query=Ren%2C+H">Hong Ren</a>, <a href="/search/eess?searchtype=author&query=Peng%2C+Z">Zhendong Peng</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Elkashlan%2C+M">Maged Elkashlan</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+D">Dongming Wang</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+J">Jiangzhou Wang</a>, <a href="/search/eess?searchtype=author&query=You%2C+X">Xiaohu You</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2405.18775v3-abstract-short" style="display: inline;"> Carrier frequency and timing synchronization play the fundamental roles in cooperative integrating communication and sensing (ISAC). To mitigate the effects of synchronization error, this paper develops a novel synchronization scheme in cell-free massive multiple-input multiple-output (mMIMO) systems. First, we characterize the impacts of pilot contamination on synchronization performance, i.e., C… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.18775v3-abstract-full').style.display = 'inline'; document.getElementById('2405.18775v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.18775v3-abstract-full" style="display: none;"> Carrier frequency and timing synchronization play the fundamental roles in cooperative integrating communication and sensing (ISAC). To mitigate the effects of synchronization error, this paper develops a novel synchronization scheme in cell-free massive multiple-input multiple-output (mMIMO) systems. First, we characterize the impacts of pilot contamination on synchronization performance, i.e., Cramer-Rao bound (CRB). Furthermore, a maximum likelihood algorithm is presented to estimate the CFO and TO among the pairing APs. Then, to minimize the sum of CRBs, we devise a synchronization strategy based on a pilot-sharing scheme by jointly optimizing the cluster classification, synchronization overhead, and pilot-sharing scheme, while simultaneously considering the overhead and each AP's synchronization requirements. To solve this NP-hard problem, we simplify it into two sub-problems, namely cluster classification problem and the pilot sharing problem. To strike a balance between synchronization performance and overhead, we first classify the clusters by using the K-means algorithm, and propose a criteria to find a good set of master APs. Then, the pilot-sharing scheme is obtained by using the swap-matching operations. Simulation results validate the accuracy of our derivations and demonstrate the effectiveness of the proposed scheme over the benchmark schemes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.18775v3-abstract-full').style.display = 'none'; document.getElementById('2405.18775v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 29 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Submitted to IEEE Journal for possible publication</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.09053">arXiv:2405.09053</a> <span> [<a href="https://arxiv.org/pdf/2405.09053">pdf</a>, <a href="https://arxiv.org/ps/2405.09053">ps</a>, <a href="https://arxiv.org/format/2405.09053">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Deep Learning-Based CSI Feedback for XL-MIMO Systems in the Near-Field Domain </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Peng%2C+Z">Zhangjie Peng</a>, <a href="/search/eess?searchtype=author&query=Liu%2C+R">Ruijing Liu</a>, <a href="/search/eess?searchtype=author&query=Li%2C+Z">Zhaotian Li</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+J">Jiangzhou Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2405.09053v2-abstract-short" style="display: inline;"> In this paper, we consider an extremely large-scale massive multiple-input-multiple-output (XL-MIMO) system. As the scale of antenna arrays increases, the range of near-field communications also expands. In this case, the signals no longer exhibit planar wave characteristics but spherical wave characteristics in the near-field channel, which makes the channel state information (CSI) highly complex… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.09053v2-abstract-full').style.display = 'inline'; document.getElementById('2405.09053v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.09053v2-abstract-full" style="display: none;"> In this paper, we consider an extremely large-scale massive multiple-input-multiple-output (XL-MIMO) system. As the scale of antenna arrays increases, the range of near-field communications also expands. In this case, the signals no longer exhibit planar wave characteristics but spherical wave characteristics in the near-field channel, which makes the channel state information (CSI) highly complex. Additionally, the increase of the antenna arrays scale also makes the size of the CSI matrix significantly increase. Therefore, CSI feedback in the near-field channel becomes highly challenging. To solve this issue, we propose a deep-learning (DL)-based ExtendNLNet that can compress the CSI, and further reduce the overhead of CSI feedback. In addition, we have introduced the Non-Local block to obtain a larger area of CSI features. Simulation results show that the proposed ExtendNLNet can significantly improve the CSI recovery quality compared to other DL-based methods. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.09053v2-abstract-full').style.display = 'none'; document.getElementById('2405.09053v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 14 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.06946">arXiv:2405.06946</a> <span> [<a href="https://arxiv.org/pdf/2405.06946">pdf</a>, <a href="https://arxiv.org/format/2405.06946">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Two-Timescale Design for Reconfigurable Intelligent Surface-Aided URLLC </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Peng%2C+Q">Qihao Peng</a>, <a href="/search/eess?searchtype=author&query=Ren%2C+H">Hong Ren</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Elkashlan%2C+M">Maged Elkashlan</a>, <a href="/search/eess?searchtype=author&query=Armada%2C+A+G">Ana Garcia Armada</a>, <a href="/search/eess?searchtype=author&query=Popovski%2C+P">Petar Popovski</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2405.06946v1-abstract-short" style="display: inline;"> In this paper, to tackle the blockage issue in massive multiple-input-multiple-output (mMIMO) systems, a reconfigurable intelligent surface (RIS) is seamlessly deployed to support devices with ultra-reliable and low-latency communications (URLLC). The transmission power of the base station and the phase shifts of the RIS are jointly devised to maximize the weighted sum rate while considering the s… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.06946v1-abstract-full').style.display = 'inline'; document.getElementById('2405.06946v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.06946v1-abstract-full" style="display: none;"> In this paper, to tackle the blockage issue in massive multiple-input-multiple-output (mMIMO) systems, a reconfigurable intelligent surface (RIS) is seamlessly deployed to support devices with ultra-reliable and low-latency communications (URLLC). The transmission power of the base station and the phase shifts of the RIS are jointly devised to maximize the weighted sum rate while considering the spatially correlation and channel estimation errors. Firstly, \textcolor{black}{the relationship between the channel estimation error and spatially correlated RIS's elements is revealed by using the linear minimum mean square error}. Secondly, based on the maximum-ratio transmission precoding, a tight lower bound of the rate under short packet transmission is derived. Finally, the NP-hard problem is decomposed into two optimization problems, where the transmission power is obtained by geometric programming and phase shifts are designed by using gradient ascent method. Besides, we have rigorously proved that the proposed algorithm can rapidly converge to a sub-optimal solution with low complexity. Simulation results confirm the tightness between the analytic results and Monte Carlo simulations. Furthermore, the two-timescale scheme provides a practical solution for the short packet transmission. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.06946v1-abstract-full').style.display = 'none'; document.getElementById('2405.06946v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">This paper has already been accepted by IEEE Transactions on Wireless Communications</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.03300">arXiv:2405.03300</a> <span> [<a href="https://arxiv.org/pdf/2405.03300">pdf</a>, <a href="https://arxiv.org/format/2405.03300">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Information Theory">cs.IT</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Active RIS-Aided Massive MIMO With Imperfect CSI and Phase Noise </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Peng%2C+Z">Zhangjie Peng</a>, <a href="/search/eess?searchtype=author&query=Zhu%2C+J">Jianchen Zhu</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Zhang%2C+Z">Zaichen Zhang</a>, <a href="/search/eess?searchtype=author&query=da+Costa%2C+D+B">Daniel Benevides da Costa</a>, <a href="/search/eess?searchtype=author&query=Elkashlan%2C+M">Maged Elkashlan</a>, <a href="/search/eess?searchtype=author&query=Karagiannidis%2C+G+K">George K. Karagiannidis</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2405.03300v1-abstract-short" style="display: inline;"> Active reconfigurable intelligent surface (RIS) has attracted significant attention as a recently proposed RIS architecture. Owing to its capability to amplify the incident signals, active RIS can mitigate the multiplicative fading effect inherent in the passive RIS-aided system. In this paper, we consider an active RIS-aided uplink multi-user massive multiple-input multiple-output (MIMO) system i… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.03300v1-abstract-full').style.display = 'inline'; document.getElementById('2405.03300v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.03300v1-abstract-full" style="display: none;"> Active reconfigurable intelligent surface (RIS) has attracted significant attention as a recently proposed RIS architecture. Owing to its capability to amplify the incident signals, active RIS can mitigate the multiplicative fading effect inherent in the passive RIS-aided system. In this paper, we consider an active RIS-aided uplink multi-user massive multiple-input multiple-output (MIMO) system in the presence of phase noise at the active RIS. Specifically, we employ a two-timescale scheme, where the beamforming at the base station (BS) is adjusted based on the instantaneous aggregated channel state information (CSI) and the statistical CSI serves as the basis for designing the phase shifts at the active RIS, so that the feedback overhead and computational complexity can be significantly reduced. The aggregated channel composed of the cascaded and direct channels is estimated by utilizing the linear minimum mean square error (LMMSE) technique. Based on the estimated channel, we derive the analytical closed-form expression of a lower bound of the achievable rate. The power scaling laws in the active RIS-aided system are investigated based on the theoretical expressions. When the transmit power of each user is scaled down by the number of BS antennas M or reflecting elements N, we find that the thermal noise will cause the lower bound of the achievable rate to approach zero, as the number of M or N increases to infinity. Moreover, an optimization approach based on genetic algorithms (GA) is introduced to tackle the phase shift optimization problem. Numerical results reveal that the active RIS can greatly enhance the performance of the considered system under various settings. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.03300v1-abstract-full').style.display = 'none'; document.getElementById('2405.03300v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2404.15469">arXiv:2404.15469</a> <span> [<a href="https://arxiv.org/pdf/2404.15469">pdf</a>, <a href="https://arxiv.org/format/2404.15469">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Information Theory">cs.IT</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> NMBEnet: Efficient Near-field mmWave Beam Training for Multiuser OFDM Systems Using Sub-6 GHz Pilots </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Liu%2C+W">Wang Liu</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Ren%2C+H">Hong Ren</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+C">Cheng-Xiang Wang</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+J">Jiangzhou Wang</a>, <a href="/search/eess?searchtype=author&query=You%2C+X">Xiaohu You</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2404.15469v1-abstract-short" style="display: inline;"> Combining millimetre-wave (mmWave) communications with an extremely large-scale antenna array (ELAA) presents a promising avenue for meeting the spectral efficiency demands of the future sixth generation (6G) mobile communications. However, beam training for mmWave ELAA systems is challenged by excessive pilot overheads as well as insufficient accuracy, as the huge near-field codebook has to be ac… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.15469v1-abstract-full').style.display = 'inline'; document.getElementById('2404.15469v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2404.15469v1-abstract-full" style="display: none;"> Combining millimetre-wave (mmWave) communications with an extremely large-scale antenna array (ELAA) presents a promising avenue for meeting the spectral efficiency demands of the future sixth generation (6G) mobile communications. However, beam training for mmWave ELAA systems is challenged by excessive pilot overheads as well as insufficient accuracy, as the huge near-field codebook has to be accounted for. In this paper, inspired by the similarity between far-field sub-6 GHz channels and near-field mmWave channels, we propose to leverage sub-6 GHz uplink pilot signals to directly estimate the optimal near-field mmWave codeword, which aims to reduce pilot overhead and bypass the channel estimation. Moreover, we adopt deep learning to perform this dual mapping function, i.e., sub-6 GHz to mmWave, far-field to near-field, and a novel neural network structure called NMBEnet is designed to enhance the precision of beam training. Specifically, when considering the orthogonal frequency division multiplexing (OFDM) communication scenarios with high user density, correlations arise both between signals from different users and between signals from different subcarriers. Accordingly, the convolutional neural network (CNN) module and graph neural network (GNN) module included in the proposed NMBEnet can leverage these two correlations to further enhance the precision of beam training. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.15469v1-abstract-full').style.display = 'none'; document.getElementById('2404.15469v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2404.13875">arXiv:2404.13875</a> <span> [<a href="https://arxiv.org/pdf/2404.13875">pdf</a>, <a href="https://arxiv.org/ps/2404.13875">ps</a>, <a href="https://arxiv.org/format/2404.13875">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Information Theory">cs.IT</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Active RIS-Aided Massive MIMO Uplink Systems with Low-Resolution ADCs </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Peng%2C+Z">Zhangjie Peng</a>, <a href="/search/eess?searchtype=author&query=Lu%2C+Z">Zecheng Lu</a>, <a href="/search/eess?searchtype=author&query=Liu%2C+X">Xue Liu</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+J">Jiangzhou Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2404.13875v1-abstract-short" style="display: inline;"> This letter considers an active reconfigurable intelligent surface (RIS)-aided multi-user uplink massive multipleinput multiple-output (MIMO) system with low-resolution analog-to-digital converters (ADCs). The letter derives the closedform approximate expression for the sum achievable rate (AR), where the maximum ratio combination (MRC) processing and low-resolution ADCs are applied at the base st… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.13875v1-abstract-full').style.display = 'inline'; document.getElementById('2404.13875v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2404.13875v1-abstract-full" style="display: none;"> This letter considers an active reconfigurable intelligent surface (RIS)-aided multi-user uplink massive multipleinput multiple-output (MIMO) system with low-resolution analog-to-digital converters (ADCs). The letter derives the closedform approximate expression for the sum achievable rate (AR), where the maximum ratio combination (MRC) processing and low-resolution ADCs are applied at the base station. The system performance is analyzed, and a genetic algorithm (GA)-based method is proposed to optimize the RIS's phase shifts for enhancing the system performance. Numerical results verify the accuracy of the derivations, and demonstrate that the active RIS has an evident performance gain over the passive RIS. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.13875v1-abstract-full').style.display = 'none'; document.getElementById('2404.13875v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.16529">arXiv:2403.16529</a> <span> [<a href="https://arxiv.org/pdf/2403.16529">pdf</a>, <a href="https://arxiv.org/format/2403.16529">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Exploit High-Dimensional RIS Information to Localization: What Is the Impact of Faulty Element? </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Wu%2C+T">Tuo Wu</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Zhi%2C+K">Kangda Zhi</a>, <a href="/search/eess?searchtype=author&query=Ren%2C+H">Hong Ren</a>, <a href="/search/eess?searchtype=author&query=Elkashlan%2C+M">Maged Elkashlan</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+C">Cheng-Xiang Wang</a>, <a href="/search/eess?searchtype=author&query=Schober%2C+R">Robert Schober</a>, <a href="/search/eess?searchtype=author&query=You%2C+X">Xiaohu You</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2403.16529v2-abstract-short" style="display: inline;"> This paper proposes a novel localization algorithm using the reconfigurable intelligent surface (RIS) received signal, i.e., RIS information. Compared with BS received signal, i.e., BS information, RIS information offers higher dimension and richer feature set, thereby providing an enhanced capacity to distinguish positions of the mobile users (MUs). Additionally, we address a practical scenario w… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.16529v2-abstract-full').style.display = 'inline'; document.getElementById('2403.16529v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.16529v2-abstract-full" style="display: none;"> This paper proposes a novel localization algorithm using the reconfigurable intelligent surface (RIS) received signal, i.e., RIS information. Compared with BS received signal, i.e., BS information, RIS information offers higher dimension and richer feature set, thereby providing an enhanced capacity to distinguish positions of the mobile users (MUs). Additionally, we address a practical scenario where RIS contains some unknown (number and places) faulty elements that cannot receive signals. Initially, we employ transfer learning to design a two-phase transfer learning (TPTL) algorithm, designed for accurate detection of faulty elements. Then our objective is to regain the information lost from the faulty elements and reconstruct the complete high-dimensional RIS information for localization. To this end, we propose a transfer-enhanced dual-stage (TEDS) algorithm. In \emph{Stage I}, we integrate the CNN and variational autoencoder (VAE) to obtain the RIS information, which in \emph{Stage II}, is input to the transferred DenseNet 121 to estimate the location of the MU. To gain more insight, we propose an alternative algorithm named transfer-enhanced direct fingerprint (TEDF) algorithm which only requires the BS information. The comparison between TEDS and TEDF reveals the effectiveness of faulty element detection and the benefits of utilizing the high-dimensional RIS information for localization. Besides, our empirical results demonstrate that the performance of the localization algorithm is dominated by the high-dimensional RIS information and is robust to unoptimized phase shifts and signal-to-noise ratio (SNR). <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.16529v2-abstract-full').style.display = 'none'; document.getElementById('2403.16529v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 25 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">17 pages, Accepted by IEEE JSAC</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.16521">arXiv:2403.16521</a> <span> [<a href="https://arxiv.org/pdf/2403.16521">pdf</a>, <a href="https://arxiv.org/format/2403.16521">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Employing High-Dimensional RIS Information for RIS-aided Localization Systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Wu%2C+T">Tuo Wu</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Zhi%2C+K">Kangda Zhi</a>, <a href="/search/eess?searchtype=author&query=Ren%2C+H">Hong Ren</a>, <a href="/search/eess?searchtype=author&query=Elkashlan%2C+M">Maged Elkashlan</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+J">Jiangzhou Wang</a>, <a href="/search/eess?searchtype=author&query=Yuen%2C+C">Chau Yuen</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2403.16521v2-abstract-short" style="display: inline;"> Reconfigurable intelligent surface (RIS)-aided localization systems have attracted extensive research attention due to their accuracy enhancement capabilities. However, most studies primarily utilized the base stations (BS) received signal, i.e., BS information, for localization algorithm design, neglecting the potential of RIS received signal, i.e., RIS information. Compared with BS information,… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.16521v2-abstract-full').style.display = 'inline'; document.getElementById('2403.16521v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.16521v2-abstract-full" style="display: none;"> Reconfigurable intelligent surface (RIS)-aided localization systems have attracted extensive research attention due to their accuracy enhancement capabilities. However, most studies primarily utilized the base stations (BS) received signal, i.e., BS information, for localization algorithm design, neglecting the potential of RIS received signal, i.e., RIS information. Compared with BS information, RIS information offers higher dimension and richer feature set, thereby significantly improving the ability to extract positions of the mobile users (MUs). Addressing this oversight, this paper explores the algorithm design based on the high-dimensional RIS information. Specifically, we first propose a RIS information reconstruction (RIS-IR) algorithm to reconstruct the high-dimensional RIS information from the low-dimensional BS information. The proposed RIS-IR algorithm comprises a data processing module for preprocessing BS information, a convolution neural network (CNN) module for feature extraction, and an output module for outputting the reconstructed RIS information. Then, we propose a transfer learning based fingerprint (TFBF) algorithm that employs the reconstructed high-dimensional RIS information for MU localization. This involves adapting a pre-trained DenseNet-121 model to map the reconstructed RIS signal to the MU's three-dimensional (3D) position. Empirical results affirm that the localization performance is significantly influenced by the high-dimensional RIS information and maintains robustness against unoptimized phase shifts. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.16521v2-abstract-full').style.display = 'none'; document.getElementById('2403.16521v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 25 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.15588">arXiv:2403.15588</a> <span> [<a href="https://arxiv.org/pdf/2403.15588">pdf</a>, <a href="https://arxiv.org/format/2403.15588">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Information Theory">cs.IT</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> RIS-assisted Cell-Free Massive MIMO Systems With Two-Timescale Design and Hardware Impairments </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Dai%2C+J">Jianxin Dai</a>, <a href="/search/eess?searchtype=author&query=Ge%2C+J">Jin Ge</a>, <a href="/search/eess?searchtype=author&query=Zhi%2C+K">Kangda Zhi</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+Y">Youguo Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2403.15588v2-abstract-short" style="display: inline;"> Integrating the reconfigurable intelligent surface (RIS) into a cell-free massive multiple-input multiple-output (CF-mMIMO) system is an effective solution to achieve high system capacity with low cost and power consumption. However, existing works of RIS-assisted systems mostly assumed perfect hardware, while the impact of hardware impairments (HWIs) is generally ignored. In this paper, we consid… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.15588v2-abstract-full').style.display = 'inline'; document.getElementById('2403.15588v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.15588v2-abstract-full" style="display: none;"> Integrating the reconfigurable intelligent surface (RIS) into a cell-free massive multiple-input multiple-output (CF-mMIMO) system is an effective solution to achieve high system capacity with low cost and power consumption. However, existing works of RIS-assisted systems mostly assumed perfect hardware, while the impact of hardware impairments (HWIs) is generally ignored. In this paper, we consider the general Rician fading channel and uplink transmission of the RIS-assisted CF-mMIMO system under transceiver impairments and RIS phase noise. To reduce the feedback overhead and power consumption, we propose a two-timescale transmission scheme to optimize the passive beamformers at RISs with statistical channel state information (CSI), while transmit beamformers at access points (APs) are designed based on instantaneous CSI. Also, the maximum ratio combining (MRC) detection is applied to the central processing unit (CPU). On this basis, we derive the closed-form approximate expression of the achievable rate, based on which the impact of HWIs and the power scaling laws are analyzed to draw useful theoretical insights. To maximize the users' sum rate or minimum rate, we first transform our rate expression into a tractable form, and then optimize the phase shifts of RISs based on an accelerated gradient ascent method. Finally, numerical results are presented to demonstrate the correctness of our derived expressions and validate the previous analysis, which provide some guidelines for the practical application of the imperfect RISs in the CF-mMIMO with transceiver HWIs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.15588v2-abstract-full').style.display = 'none'; document.getElementById('2403.15588v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 22 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">51 pages, 11 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.12781">arXiv:2403.12781</a> <span> [<a href="https://arxiv.org/pdf/2403.12781">pdf</a>, <a href="https://arxiv.org/format/2403.12781">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Large-Scale RIS Enabled Air-Ground Channels: Near-Field Modeling and Analysis </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Jiang%2C+H">Hao Jiang</a>, <a href="/search/eess?searchtype=author&query=Shi%2C+W">Wangqi Shi</a>, <a href="/search/eess?searchtype=author&query=Zhang%2C+Z">Zaichen Zhang</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Wu%2C+Q">Qingqing Wu</a>, <a href="/search/eess?searchtype=author&query=Shu%2C+F">Feng Shu</a>, <a href="/search/eess?searchtype=author&query=Liu%2C+R">Ruiqi Liu</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+J">Jiangzhou Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2403.12781v1-abstract-short" style="display: inline;"> Existing works mainly rely on the far-field planar-wave-based channel model to assess the performance of reconfigurable intelligent surface (RIS)-enabled wireless communication systems. However, when the transmitter and receiver are in near-field ranges, this will result in relatively low computing accuracy. To tackle this challenge, we initially develop an analytical framework for sub-array parti… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.12781v1-abstract-full').style.display = 'inline'; document.getElementById('2403.12781v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.12781v1-abstract-full" style="display: none;"> Existing works mainly rely on the far-field planar-wave-based channel model to assess the performance of reconfigurable intelligent surface (RIS)-enabled wireless communication systems. However, when the transmitter and receiver are in near-field ranges, this will result in relatively low computing accuracy. To tackle this challenge, we initially develop an analytical framework for sub-array partitioning. This framework divides the large-scale RIS array into multiple sub-arrays, effectively reducing modeling complexity while maintaining acceptable accuracy. Then, we develop a beam domain channel model based on the proposed sub-array partition framework for large-scale RIS-enabled UAV-to-vehicle communication systems, which can be used to efficiently capture the sparse features in RIS-enabled UAV-to-vehicle channels in both near-field and far-field ranges. Furthermore, some important propagation characteristics of the proposed channel model, including the spatial cross-correlation functions (CCFs), temporal auto-correlation functions (ACFs), frequency correlation functions (CFs), and channel capacities with respect to the different physical features of the RIS and non-stationary properties of the channel model are derived and analyzed. Finally, simulation results are provided to demonstrate that the proposed framework is helpful to achieve a good tradeoff between model complexity and accuracy for investigating the channel propagation characteristics, and therefore providing highly-efficient communications in RIS-enabled UAV-to-vehicle wireless networks. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.12781v1-abstract-full').style.display = 'none'; document.getElementById('2403.12781v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.12453">arXiv:2403.12453</a> <span> [<a href="https://arxiv.org/pdf/2403.12453">pdf</a>, <a href="https://arxiv.org/format/2403.12453">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Deep Learning-Based CSI Feedback for RIS-Aided Massive MIMO Systems with Time Correlation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Peng%2C+Z">Zhangjie Peng</a>, <a href="/search/eess?searchtype=author&query=Li%2C+Z">Zhaotian Li</a>, <a href="/search/eess?searchtype=author&query=Liu%2C+R">Ruijing Liu</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Yuan%2C+F">Feiniu Yuan</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+J">Jiangzhou Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2403.12453v1-abstract-short" style="display: inline;"> In this paper, we consider an reconfigurable intelligent surface (RIS)-aided frequency division duplex (FDD) massive multiple-input multiple-output (MIMO) downlink system.In the FDD systems, the downlink channel state information (CSI) should be sent to the base station through the feedback link. However, the overhead of CSI feedback occupies substantial uplink bandwidth resources in RIS-aided com… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.12453v1-abstract-full').style.display = 'inline'; document.getElementById('2403.12453v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.12453v1-abstract-full" style="display: none;"> In this paper, we consider an reconfigurable intelligent surface (RIS)-aided frequency division duplex (FDD) massive multiple-input multiple-output (MIMO) downlink system.In the FDD systems, the downlink channel state information (CSI) should be sent to the base station through the feedback link. However, the overhead of CSI feedback occupies substantial uplink bandwidth resources in RIS-aided communication systems. In this work, we propose a deep learning (DL)-based scheme to reduce the overhead of CSI feedback by compressing the cascaded CSI. In the practical RIS-aided communication systems, the cascaded channel at the adjacent slots inevitably has time correlation. We use long short-term memory to learn time correlation, which can help the neural network to improve the recovery quality of the compressed CSI. Moreover, the attention mechanism is introduced to further improve the CSI recovery quality. Simulation results demonstrate that our proposed DLbased scheme can significantly outperform other DL-based methods in terms of the CSI recovery quality <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.12453v1-abstract-full').style.display = 'none'; document.getElementById('2403.12453v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.11061">arXiv:2403.11061</a> <span> [<a href="https://arxiv.org/pdf/2403.11061">pdf</a>, <a href="https://arxiv.org/format/2403.11061">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Beamforming Design for Double-Active-RIS-aided Communication Systems with Inter-Excitation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Wang%2C+B">Boshi Wang</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Ren%2C+H">Hong Ren</a>, <a href="/search/eess?searchtype=author&query=Yu%2C+Z">Zhiyuan Yu</a>, <a href="/search/eess?searchtype=author&query=Zhang%2C+Y">Yang Zhang</a>, <a href="/search/eess?searchtype=author&query=Liu%2C+M">Mengyu Liu</a>, <a href="/search/eess?searchtype=author&query=Zhou%2C+G">Gui Zhou</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2403.11061v2-abstract-short" style="display: inline;"> In this paper, we investigate a double-active-reconfigurable intelligent surface (RIS)-aided downlink wireless communication system, where a multi-antenna base station (BS) serves multiple single-antenna users with both double reflection and single reflection links. Due to the signal amplification capability of active RISs, they can effectively mitigate the multiplicative fading effect. However, t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.11061v2-abstract-full').style.display = 'inline'; document.getElementById('2403.11061v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.11061v2-abstract-full" style="display: none;"> In this paper, we investigate a double-active-reconfigurable intelligent surface (RIS)-aided downlink wireless communication system, where a multi-antenna base station (BS) serves multiple single-antenna users with both double reflection and single reflection links. Due to the signal amplification capability of active RISs, they can effectively mitigate the multiplicative fading effect. However, this also induces signal bouncing between the two active RISs that cannot be ignored. This phenomenon is termed as the "inter-excitation" effect and is characterized in the received signal by proposing a feedback-type model. Based on the signal model, we formulate a weighted sum rate (WSR) maximization problem by jointly optimizing the beamforming matrix at the BS and the reflecting coefficient matrices at the two active RISs, subject to power constraints at the BS and active RISs, as well as the maximum amplification gain constraints of the active RISs. To solve this non-convex problem, we first transform the problem into a more tractable form using the fractional programming (FP) method. Then, by introducing auxiliary variables, the problem can be converted into an equivalent form that can be solved by using a penalty dual decomposition (PDD) algorithm. Finally, simulation results indicate that it proposed scheme outperforms benchmark schemes with single active RIS and double passive RISs in terms of achievable rate. Furthermore, the results demonstrate that the proposed scheme can enhance the WSR by 30\% compared to scenarios that do not take this effect into account when the maximum amplification gain is 40 dB. Additionally, the proposed scheme is capable of achieving high WSR performance at most locations where double active RISs are deployed between the BS and the users, thereby providing greater flexibility in their positioning. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.11061v2-abstract-full').style.display = 'none'; document.getElementById('2403.11061v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.10323">arXiv:2403.10323</a> <span> [<a href="https://arxiv.org/pdf/2403.10323">pdf</a>, <a href="https://arxiv.org/ps/2403.10323">ps</a>, <a href="https://arxiv.org/format/2403.10323">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Joint Optimization for Achieving Covertness in MIMO Over-the-Air Computation Networks </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Yao%2C+J">Junteng Yao</a>, <a href="/search/eess?searchtype=author&query=Wu%2C+T">Tuo Wu</a>, <a href="/search/eess?searchtype=author&query=Jin%2C+M">Ming Jin</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Li%2C+Q">Quanzhong Li</a>, <a href="/search/eess?searchtype=author&query=Yuan%2C+J">Jinhong Yuan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2403.10323v1-abstract-short" style="display: inline;"> This paper investigates covert data transmission within a multiple-input multiple-output (MIMO) over-the-air computation (AirComp) network, where sensors transmit data to the access point (AP) while guaranteeing covertness to the warden (Willie). Simultaneously, the AP introduces artificial noise (AN) to confuse Willie, meeting the covert requirement. We address the challenge of minimizing mean-sq… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.10323v1-abstract-full').style.display = 'inline'; document.getElementById('2403.10323v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.10323v1-abstract-full" style="display: none;"> This paper investigates covert data transmission within a multiple-input multiple-output (MIMO) over-the-air computation (AirComp) network, where sensors transmit data to the access point (AP) while guaranteeing covertness to the warden (Willie). Simultaneously, the AP introduces artificial noise (AN) to confuse Willie, meeting the covert requirement. We address the challenge of minimizing mean-square-error (MSE) of the AP, while considering transmit power constraints at both the AP and the sensors, as well as ensuring the covert transmission to Willie with a low detection error probability (DEP). However, obtaining globally optimal solutions for the investigated non-convex problem is challenging due to the interdependence of optimization variables. To tackle this problem, we introduce an exact penalty algorithm and transform the optimization problem into a difference-of-convex (DC) form problem to find a locally optimal solution. Simulation results showcase the superior performance in terms of our proposed scheme in comparison to the benchmark schemes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.10323v1-abstract-full').style.display = 'none'; document.getElementById('2403.10323v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.09330">arXiv:2403.09330</a> <span> [<a href="https://arxiv.org/pdf/2403.09330">pdf</a>, <a href="https://arxiv.org/ps/2403.09330">ps</a>, <a href="https://arxiv.org/format/2403.09330">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Radar Rainbow Beams For Wideband mmWave Communication: Beam Training And Tracking </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Zhou%2C+G">Gui Zhou</a>, <a href="/search/eess?searchtype=author&query=Garkisch%2C+M">Moritz Garkisch</a>, <a href="/search/eess?searchtype=author&query=Peng%2C+Z">Zhendong Peng</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Schober%2C+R">Robert Schober</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2403.09330v1-abstract-short" style="display: inline;"> We propose a novel integrated sensing and communication (ISAC) system that leverages sensing to assist communication, ensuring fast initial access, seamless user tracking, and uninterrupted communication for millimeter wave (mmWave) wideband systems. True-time-delayers (TTDs) are utilized to generate frequency-dependent radar rainbow beams by controlling the beam squint effect. These beams cover u… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.09330v1-abstract-full').style.display = 'inline'; document.getElementById('2403.09330v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.09330v1-abstract-full" style="display: none;"> We propose a novel integrated sensing and communication (ISAC) system that leverages sensing to assist communication, ensuring fast initial access, seamless user tracking, and uninterrupted communication for millimeter wave (mmWave) wideband systems. True-time-delayers (TTDs) are utilized to generate frequency-dependent radar rainbow beams by controlling the beam squint effect. These beams cover users across the entire angular space simultaneously for fast beam training using just one orthogonal frequency-division multiplexing (OFDM) symbol. Three detection and estimation schemes are proposed based on radar rainbow beams for estimation of the users' angles, distances, and velocities, which are then exploited for communication beamformer design. The first proposed scheme utilizes a single-antenna radar receiver and one set of rainbow beams, but may cause a Doppler ambiguity. To tackle this limitation, two additional schemes are introduced, utilizing two sets of rainbow beams and a multi-antenna receiver, respectively. Furthermore, the proposed detection and estimation schemes are extended to realize user tracking by choosing different subsets of OFDM subcarriers. This approach eliminates the need to switch phase shifters and TTDs, which are typically necessary in existing tracking technologies, thereby reducing the demands on the control circurity. Simulation results reveal the effectiveness of the proposed rainbow beam-based training and tracking methods for mobile users. Notably, the scheme employing a multi-antenna radar receiver can accurately estimate the channel parameters and can support communication rates comparable to those achieved with perfect channel information. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.09330v1-abstract-full').style.display = 'none'; document.getElementById('2403.09330v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">32 pages</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.09058">arXiv:2403.09058</a> <span> [<a href="https://arxiv.org/pdf/2403.09058">pdf</a>, <a href="https://arxiv.org/ps/2403.09058">ps</a>, <a href="https://arxiv.org/format/2403.09058">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Information Theory">cs.IT</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Performance Analysis on RIS-Aided Wideband Massive MIMO OFDM Systems with Low-Resolution ADCs </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Chen%2C+X">Xianzhe Chen</a>, <a href="/search/eess?searchtype=author&query=Ren%2C+H">Hong Ren</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Peng%2C+Z">Zhangjie Peng</a>, <a href="/search/eess?searchtype=author&query=Zhi%2C+K">Kangda Zhi</a>, <a href="/search/eess?searchtype=author&query=Liu%2C+Y">Yong Liu</a>, <a href="/search/eess?searchtype=author&query=Xi%2C+X">Xiaojun Xi</a>, <a href="/search/eess?searchtype=author&query=Armada%2C+A+G">Ana Garcia Armada</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+C">Cheng-Xiang Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2403.09058v1-abstract-short" style="display: inline;"> This paper investigates a reconfigurable intelligent surface (RIS)-aided wideband massive multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system with low-resolution analog-to-digital converters (ADCs). Frequency-selective Rician fading channels are considered, and the OFDM data transmission process is presented in time domain. This paper derives the closed-f… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.09058v1-abstract-full').style.display = 'inline'; document.getElementById('2403.09058v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.09058v1-abstract-full" style="display: none;"> This paper investigates a reconfigurable intelligent surface (RIS)-aided wideband massive multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system with low-resolution analog-to-digital converters (ADCs). Frequency-selective Rician fading channels are considered, and the OFDM data transmission process is presented in time domain. This paper derives the closed-form approximate expression of the uplink achievable rate, based on which the asymptotic system performance is analyzed when the number of the antennas at the base station and the number of reflecting elements at the RIS grow to infinity. Besides, the power scaling laws of the considered system are revealed to provide energy-saving insights. Furthermore, this paper proposes a gradient ascent-based algorithm to design the phase shifts of the RIS for maximizing the minimum user rate. Finally, numerical results are presented to verify the correctness of analytical conclusions and draw insights. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.09058v1-abstract-full').style.display = 'none'; document.getElementById('2403.09058v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.05246">arXiv:2403.05246</a> <span> [<a href="https://arxiv.org/pdf/2403.05246">pdf</a>, <a href="https://arxiv.org/format/2403.05246">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Image and Video Processing">eess.IV</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Computer Vision and Pattern Recognition">cs.CV</span> </div> </div> <p class="title is-5 mathjax"> LightM-UNet: Mamba Assists in Lightweight UNet for Medical Image Segmentation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Liao%2C+W">Weibin Liao</a>, <a href="/search/eess?searchtype=author&query=Zhu%2C+Y">Yinghao Zhu</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+X">Xinyuan Wang</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Chengwei Pan</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+Y">Yasha Wang</a>, <a href="/search/eess?searchtype=author&query=Ma%2C+L">Liantao Ma</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2403.05246v2-abstract-short" style="display: inline;"> UNet and its variants have been widely used in medical image segmentation. However, these models, especially those based on Transformer architectures, pose challenges due to their large number of parameters and computational loads, making them unsuitable for mobile health applications. Recently, State Space Models (SSMs), exemplified by Mamba, have emerged as competitive alternatives to CNN and Tr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.05246v2-abstract-full').style.display = 'inline'; document.getElementById('2403.05246v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.05246v2-abstract-full" style="display: none;"> UNet and its variants have been widely used in medical image segmentation. However, these models, especially those based on Transformer architectures, pose challenges due to their large number of parameters and computational loads, making them unsuitable for mobile health applications. Recently, State Space Models (SSMs), exemplified by Mamba, have emerged as competitive alternatives to CNN and Transformer architectures. Building upon this, we employ Mamba as a lightweight substitute for CNN and Transformer within UNet, aiming at tackling challenges stemming from computational resource limitations in real medical settings. To this end, we introduce the Lightweight Mamba UNet (LightM-UNet) that integrates Mamba and UNet in a lightweight framework. Specifically, LightM-UNet leverages the Residual Vision Mamba Layer in a pure Mamba fashion to extract deep semantic features and model long-range spatial dependencies, with linear computational complexity. Extensive experiments conducted on two real-world 2D/3D datasets demonstrate that LightM-UNet surpasses existing state-of-the-art literature. Notably, when compared to the renowned nnU-Net, LightM-UNet achieves superior segmentation performance while drastically reducing parameter and computation costs by 116x and 21x, respectively. This highlights the potential of Mamba in facilitating model lightweighting. Our code implementation is publicly available at https://github.com/MrBlankness/LightM-UNet. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.05246v2-abstract-full').style.display = 'none'; document.getElementById('2403.05246v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 8 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.04269">arXiv:2403.04269</a> <span> [<a href="https://arxiv.org/pdf/2403.04269">pdf</a>, <a href="https://arxiv.org/format/2403.04269">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Information Theory">cs.IT</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Secure MIMO Communication Relying on Movable Antennas </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Tang%2C+J">Jun Tang</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Zhang%2C+Y">Yang Zhang</a>, <a href="/search/eess?searchtype=author&query=Ren%2C+H">Hong Ren</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+K">Kezhi Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2403.04269v1-abstract-short" style="display: inline;"> This paper considers a movable antenna (MA)-aided secure multiple-input multiple-output (MIMO) communication system consisting of a base station (BS), a legitimate information receiver (IR) and an eavesdropper (Eve), where the BS is equipped with MAs to enhance the system's physical layer security (PLS). Specifically, we aim to maximize the secrecy rate (SR) by jointly optimizing the transmit prec… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.04269v1-abstract-full').style.display = 'inline'; document.getElementById('2403.04269v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.04269v1-abstract-full" style="display: none;"> This paper considers a movable antenna (MA)-aided secure multiple-input multiple-output (MIMO) communication system consisting of a base station (BS), a legitimate information receiver (IR) and an eavesdropper (Eve), where the BS is equipped with MAs to enhance the system's physical layer security (PLS). Specifically, we aim to maximize the secrecy rate (SR) by jointly optimizing the transmit precoding (TPC) matrix, the artificial noise (AN) covariance matrix and the MAs' positions under the constraints of the maximum transmit power and the minimum distance between MAs. To solve this non-convex problem with highly coupled optimization variables, the block coordinate descent (BCD) method is applied to alternately update the variables. Specifically, we first reformulate the SR into a tractable form by utilizing the minimum mean square error (MMSE) method, and derive the optimal TPC matrix and the AN covariance matrix with fixed MAs' positions by applying the Lagrangian multiplier method in semi-closed forms. Then, the majorization-minimization (MM) algorithm is employed to iteratively optimize each MA's position while keeping others fixed. Finally, simulation results are provided to demonstrate the effectiveness of the proposed algorithms and the significant advantages of the MA-aided system over conventional fixed position antenna (FPA)-based system in enhancing system's security. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.04269v1-abstract-full').style.display = 'none'; document.getElementById('2403.04269v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.02942">arXiv:2403.02942</a> <span> [<a href="https://arxiv.org/pdf/2403.02942">pdf</a>, <a href="https://arxiv.org/format/2403.02942">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Information Theory">cs.IT</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Channel Estimation for mmWave MIMO-OFDM Systems in High-Mobility Scenarios: Instantaneous Model or Statistical Model? </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Wang%2C+R">Ruizhe Wang</a>, <a href="/search/eess?searchtype=author&query=Ren%2C+H">Hong Ren</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Zhou%2C+G">Gui Zhou</a>, <a href="/search/eess?searchtype=author&query=Weng%2C+R">Ruisong Weng</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+J">Jiangzhou Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2403.02942v2-abstract-short" style="display: inline;"> Classical linear statistical models, like the first-order auto-regressive (AR) model, are commonly used as channel model in high-mobility scenarios. However, compared to sub-6G, the effect of Doppler frequency shifts is more significant at millimeter wave (mmWave) frequencies, and the effectiveness of the statistical channel model in high-mobility mmWave scenarios should be reconsidered. In this p… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.02942v2-abstract-full').style.display = 'inline'; document.getElementById('2403.02942v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.02942v2-abstract-full" style="display: none;"> Classical linear statistical models, like the first-order auto-regressive (AR) model, are commonly used as channel model in high-mobility scenarios. However, compared to sub-6G, the effect of Doppler frequency shifts is more significant at millimeter wave (mmWave) frequencies, and the effectiveness of the statistical channel model in high-mobility mmWave scenarios should be reconsidered. In this paper, we investigate the channel estimation for mmWave multiple-input multiple-output-(MIMO) orthogonal frequency division multiplexing (OFDM) systems in high-mobility scenarios, with the focus on the comparison between the instantaneous channel model and the statistical channel model. For the instantaneous model, by leveraging the low-rank nature of mmWave channels and the multidimensional characteristics of MIMO-OFDM signals across space, time, and frequency, the received signals are structured as a fourth-order tensor fitting a low-rank CANDECOMP/PARAFAC (CP) model. Then, to solve the CP decomposition problem, an estimation of signal parameters via rotational invariance techniques (ESPRIT)-type decomposition based channel estimation method is proposed by exploring the Vandermonde structure of factor matrix, and the channel parameters are then estimated from the factor matrices. We analyze the uniqueness condition of the CP decomposition and develop a concise derivation of the Cramer-Rao bound (CRB) for channel parameters. Simulations show that our method outperforms the existing benchmarks. Furthermore, the results based on the wireless environment generated by Wireless InSite verify that the channel estimation based on the instantaneous channel model performs better than that based on the statistical channel model. Therefore, the instantaneous channel model is recommended for designing channel estimation algorithm for mmWave systems in high-mobility scenarios. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.02942v2-abstract-full').style.display = 'none'; document.getElementById('2403.02942v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 5 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.02028">arXiv:2403.02028</a> <span> [<a href="https://arxiv.org/pdf/2403.02028">pdf</a>, <a href="https://arxiv.org/format/2403.02028">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Target Localization in Cooperative ISAC Systems: A Scheme Based on 5G NR OFDM Signals </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Zhang%2C+Z">Zhenkun Zhang</a>, <a href="/search/eess?searchtype=author&query=Ren%2C+H">Hong Ren</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Hong%2C+S">Sheng Hong</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+D">Dongming Wang</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+J">Jiangzhou Wang</a>, <a href="/search/eess?searchtype=author&query=You%2C+X">Xiaohu You</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2403.02028v2-abstract-short" style="display: inline;"> The integration of sensing capabilities into communication systems, by sharing physical resources, has a significant potential for reducing spectrum, hardware, and energy costs while inspiring innovative applications. Cooperative networks, in particular, are expected to enhance sensing services by enlarging the coverage area and enriching sensing measurements, thus improving the service availabili… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.02028v2-abstract-full').style.display = 'inline'; document.getElementById('2403.02028v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.02028v2-abstract-full" style="display: none;"> The integration of sensing capabilities into communication systems, by sharing physical resources, has a significant potential for reducing spectrum, hardware, and energy costs while inspiring innovative applications. Cooperative networks, in particular, are expected to enhance sensing services by enlarging the coverage area and enriching sensing measurements, thus improving the service availability and accuracy. This paper proposes a cooperative integrated sensing and communication (ISAC) framework by leveraging information-bearing orthogonal frequency division multiplexing (OFDM) signals transmitted by access points (APs). Specifically, we propose a two-stage scheme for target localization, where communication signals are reused as sensing reference signals based on the system information shared at the central processing unit (CPU). In Stage I, we propose a twodimensional fast Fourier transform (2D-FFT)-based algorithm to measure the ranges of scattered paths induced by targets, through the extraction of delay and Doppler information from the sensing channels between APs. Then, the target locations are estimated in Stage II based on these range measurements. Considering the potential occurrence of ill-conditioned measurements with large error during the extraction of time-frequency information, we propose an efficient algorithm to match the range measurements with the targets while eliminating ill-onditioned measurements, achieving high-accuracy target localization. In addition, based on the transmission configurations defined in the fifth generation (5G) standards, we elucidate the performance trade-offs in both communication and sensing, and extend the proposed sensing scheme for general scenarios. Finally, numerical results confirm the effectiveness of our sensing scheme and the cooperative gain of the ISAC framework. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.02028v2-abstract-full').style.display = 'none'; document.getElementById('2403.02028v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 4 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.02012">arXiv:2403.02012</a> <span> [<a href="https://arxiv.org/pdf/2403.02012">pdf</a>, <a href="https://arxiv.org/format/2403.02012">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Information Theory">cs.IT</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> OTFS vs OFDM: Which is Superior in Multiuser LEO Satellite Communications </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Liu%2C+Y">Yu Liu</a>, <a href="/search/eess?searchtype=author&query=Chen%2C+M">Ming Chen</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Gong%2C+T">Tantao Gong</a>, <a href="/search/eess?searchtype=author&query=Yuan%2C+J">Jinhong Yuan</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+J">Jiangzhou Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2403.02012v1-abstract-short" style="display: inline;"> Orthogonal time frequency space (OTFS) modulation, a delay-Doppler (DD) domain communication scheme exhibiting strong robustness against the Doppler shifts, has the potentials to be employed in LEO satellite communications. However, the performance comparison with the orthogonal frequency division multiplexing (OFDM) modulation and the resource allocation scheme for multiuser OTFS-based LEO satell… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.02012v1-abstract-full').style.display = 'inline'; document.getElementById('2403.02012v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.02012v1-abstract-full" style="display: none;"> Orthogonal time frequency space (OTFS) modulation, a delay-Doppler (DD) domain communication scheme exhibiting strong robustness against the Doppler shifts, has the potentials to be employed in LEO satellite communications. However, the performance comparison with the orthogonal frequency division multiplexing (OFDM) modulation and the resource allocation scheme for multiuser OTFS-based LEO satellite communication system have rarely been investigated. In this paper, we conduct a performance comparison under various channel conditions between the OTFS and OFDM modulations, encompassing evaluations of sum-rate and bit error ratio (BER). Additionally, we investigate the joint optimal allocation of power and delay-Doppler resource blocks aiming at maximizing sum-rate for multiuser downlink OTFS-based LEO satellite communication systems. Unlike the conventional modulations relaying on complex input-output relations within the Time-Frequency (TF) domain, the OTFS modulation exploits both time and frequency diversities, i.e., delay and Doppler shifts remain constant during a OTFS frame, which facilitates a DD domain input-output simple relation for our investigation. We transform the resulting non-convex and combinatorial optimization problem into an equivalent difference of convex problem by decoupling the conditional constraints, and solve the transformed problem via penalty convex-concave procedure algorithm. Simulation results demonstrate that the OTFS modulation is robust to carrier frequency offsets (CFO) caused by high-mobility of LEO satellites, and has superior performance to the OFDM modulation. Moreover, numerical results indicate that our proposed resource allocation scheme has higher sum-rate than existed schemes for the OTFS modulation, such as delay divided multiple access and Doppler divided multiple access, especially in the high signal-to-noise ratio (SNR) regime. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.02012v1-abstract-full').style.display = 'none'; document.getElementById('2403.02012v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 9 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.00453">arXiv:2403.00453</a> <span> [<a href="https://arxiv.org/pdf/2403.00453">pdf</a>, <a href="https://arxiv.org/ps/2403.00453">ps</a>, <a href="https://arxiv.org/format/2403.00453">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Exploring Fairness for FAS-assisted Communication Systems: from NOMA to OMA </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Yao%2C+J">Junteng Yao</a>, <a href="/search/eess?searchtype=author&query=Zhou%2C+L">Liaoshi Zhou</a>, <a href="/search/eess?searchtype=author&query=Wu%2C+T">Tuo Wu</a>, <a href="/search/eess?searchtype=author&query=Jin%2C+M">Ming Jin</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Elkashlan%2C+M">Maged Elkashlan</a>, <a href="/search/eess?searchtype=author&query=Wong%2C+K">Kai-Kit Wong</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2403.00453v1-abstract-short" style="display: inline;"> This paper addresses the fairness issue within fluid antenna system (FAS)-assisted non-orthogonal multiple access (NOMA) and orthogonal multiple access (OMA) systems, where a single fixed-antenna base station (BS) transmits superposition-coded signals to two users, each with a single fluid antenna. We define fairness through the minimization of the maximum outage probability for the two users, und… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.00453v1-abstract-full').style.display = 'inline'; document.getElementById('2403.00453v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.00453v1-abstract-full" style="display: none;"> This paper addresses the fairness issue within fluid antenna system (FAS)-assisted non-orthogonal multiple access (NOMA) and orthogonal multiple access (OMA) systems, where a single fixed-antenna base station (BS) transmits superposition-coded signals to two users, each with a single fluid antenna. We define fairness through the minimization of the maximum outage probability for the two users, under total resource constraints for both FAS-assisted NOMA and OMA systems. Specifically, in the FAS-assisted NOMA systems, we study both a special case and the general case, deriving a closed-form solution for the former and applying a bisection search method to find the optimal solution for the latter. Moreover, for the general case, we derive a locally optimal closed-form solution to achieve fairness. In the FAS-assisted OMA systems, to deal with the non-convex optimization problem with coupling of the variables in the objective function, we employ an approximation strategy to facilitate a successive convex approximation (SCA)-based algorithm, achieving locally optimal solutions for both cases. Empirical analysis validates that our proposed solutions outperform conventional NOMA and OMA benchmarks in terms of fairness. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.00453v1-abstract-full').style.display = 'none'; document.getElementById('2403.00453v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 1 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2402.17281">arXiv:2402.17281</a> <span> [<a href="https://arxiv.org/pdf/2402.17281">pdf</a>, <a href="https://arxiv.org/format/2402.17281">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> GAN Based Near-Field Channel Estimation for Extremely Large-Scale MIMO Systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Ye%2C+M">Ming Ye</a>, <a href="/search/eess?searchtype=author&query=Liang%2C+X">Xiao Liang</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Xu%2C+Y">Yinfei Xu</a>, <a href="/search/eess?searchtype=author&query=Jiang%2C+M">Ming Jiang</a>, <a href="/search/eess?searchtype=author&query=Li%2C+C">Chunguo Li</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2402.17281v2-abstract-short" style="display: inline;"> Extremely large-scale multiple-input-multiple-output (XL-MIMO) is a promising technique to achieve ultra-high spectral efficiency for future 6G communications. The mixed line-of-sight (LoS) and non-line-of-sight (NLoS) XL-MIMO near-field channel model is adopted to describe the XL-MIMO near-field channel accurately. In this paper, a generative adversarial network (GAN) variant based channel estima… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.17281v2-abstract-full').style.display = 'inline'; document.getElementById('2402.17281v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2402.17281v2-abstract-full" style="display: none;"> Extremely large-scale multiple-input-multiple-output (XL-MIMO) is a promising technique to achieve ultra-high spectral efficiency for future 6G communications. The mixed line-of-sight (LoS) and non-line-of-sight (NLoS) XL-MIMO near-field channel model is adopted to describe the XL-MIMO near-field channel accurately. In this paper, a generative adversarial network (GAN) variant based channel estimation method is proposed for XL-MIMO systems. Specifically, the GAN variant is developed to simultaneously estimate the LoS and NLoS path components of the XL-MIMO channel. The initially estimated channels instead of the received signals are input into the GAN variant as the conditional input to generate the XL-MIMO channels more efficiently. The GAN variant not only learns the mapping from the initially estimated channels to the XL-MIMO channels but also learns an adversarial loss. Moreover, we combine the adversarial loss with a conventional loss function to ensure the correct direction of training the generator. To further enhance the estimation performance, we investigate the impact of the hyper-parameter of the loss function on the performance of our method. Simulation results show that the proposed method outperforms the existing channel estimation approaches in the adopted channel model. In addition, the proposed method surpasses the Cram$\acute{\mathbf{e}}$r-Rao lower bound (CRLB) under low pilot overhead. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.17281v2-abstract-full').style.display = 'none'; document.getElementById('2402.17281v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 17 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 27 February, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 9 figures, 3 tables, accepted by IEEE TGCN</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2402.13692">arXiv:2402.13692</a> <span> [<a href="https://arxiv.org/pdf/2402.13692">pdf</a>, <a href="https://arxiv.org/format/2402.13692">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> A Framework of RIS-assisted ICSC User-centric Based Systems: Latency Optimization and Design </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Wan%2C+J">Jiahua Wan</a>, <a href="/search/eess?searchtype=author&query=Ren%2C+H">Hong Ren</a>, <a href="/search/eess?searchtype=author&query=Yu%2C+Z">Zhiyuan Yu</a>, <a href="/search/eess?searchtype=author&query=Zhang%2C+Z">Zhenkun Zhang</a>, <a href="/search/eess?searchtype=author&query=Zhang%2C+Y">Yang Zhang</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+J">Jiangzhou Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2402.13692v3-abstract-short" style="display: inline;"> This paper studies a comprehensive framework for reconfigurable intelligent surface (RIS)-assisted integrated communication, sensing, and computation (ICSC) systems with a User-centric focus. The study encompasses two scenarios: the general multi-user equipment (UE) scenario and the simplified single-UE scenario. To satisfy the critical need for time-efficient sensing, we investigate the latency m… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.13692v3-abstract-full').style.display = 'inline'; document.getElementById('2402.13692v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2402.13692v3-abstract-full" style="display: none;"> This paper studies a comprehensive framework for reconfigurable intelligent surface (RIS)-assisted integrated communication, sensing, and computation (ICSC) systems with a User-centric focus. The study encompasses two scenarios: the general multi-user equipment (UE) scenario and the simplified single-UE scenario. To satisfy the critical need for time-efficient sensing, we investigate the latency minimization problem, subject to constraints on UEs' transmit power, radar signal-to-interference-plus-noise-ratio (SINR), RIS phase shift, and computation capability. To address the formulated non-convex problem in the multi-UE scenario, we decouple the original problem into two subproblems, where the computational and beamforming settings are optimized alternately. Specifically, for the computational settings, we derive a closed-form solution for the offloading volume and propose a low-complexity algorithm based on the bisection search method to optimize the edge computing resource allocation. Additionally, we employ two equivalent transformations to address the challenge posed by the non-convex sum-of-ratios form in the objective function (OF) of the subproblem related to active and passive beamforming. Several techniques are then combined to address these subproblems. Furthermore, a low-complexity algorithm that offers closed-form solutions is developed for the simplified single UE scenario. Finally, simulation results substantiate the effectiveness of the proposed framework. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.13692v3-abstract-full').style.display = 'none'; document.getElementById('2402.13692v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 February, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2402.13597">arXiv:2402.13597</a> <span> [<a href="https://arxiv.org/pdf/2402.13597">pdf</a>, <a href="https://arxiv.org/format/2402.13597">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Information Theory">cs.IT</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Near-Field Multiuser Beam-Training for Extremely Large-Scale MIMO Systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Liu%2C+W">Wang Liu</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Ren%2C+H">Hong Ren</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+J">Jiangzhou Wang</a>, <a href="/search/eess?searchtype=author&query=Schober%2C+R">Robert Schober</a>, <a href="/search/eess?searchtype=author&query=Hanzo%2C+L">Lajos Hanzo</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2402.13597v2-abstract-short" style="display: inline;"> Extremely large-scale multiple-input multiple-output (XL-MIMO) systems are capable of improving spectral efficiency by employing far more antennas than conventional massive MIMO at the base station (BS). However, beam training in multiuser XL-MIMO systems is challenging. To tackle these issues, we conceive a three-phase graph neural network (GNN)-based beam training scheme for multiuser XL-MIMO sy… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.13597v2-abstract-full').style.display = 'inline'; document.getElementById('2402.13597v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2402.13597v2-abstract-full" style="display: none;"> Extremely large-scale multiple-input multiple-output (XL-MIMO) systems are capable of improving spectral efficiency by employing far more antennas than conventional massive MIMO at the base station (BS). However, beam training in multiuser XL-MIMO systems is challenging. To tackle these issues, we conceive a three-phase graph neural network (GNN)-based beam training scheme for multiuser XL-MIMO systems. In the first phase, only far-field wide beams have to be tested for each user and the GNN is utilized to map the beamforming gain information of the far-field wide beams to the optimal near-field beam for each user. In addition, the proposed GNN-based scheme can exploit the position-correlation between adjacent users for further improvement of the accuracy of beam training. In the second phase, a beam allocation scheme based on the probability vectors produced at the outputs of GNNs is proposed to address the above beam-direction conflicts between users. In the third phase, the hybrid TBF is designed for further reducing the inter-user interference. Our simulation results show that the proposed scheme improves the beam training performance of the benchmarks. Moreover, the performance of the proposed beam training scheme approaches that of an exhaustive search, despite requiring only about 7% of the pilot overhead. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.13597v2-abstract-full').style.display = 'none'; document.getElementById('2402.13597v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 February, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">submitted to IEEE</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2402.10687">arXiv:2402.10687</a> <span> [<a href="https://arxiv.org/pdf/2402.10687">pdf</a>, <a href="https://arxiv.org/format/2402.10687">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Information Theory">cs.IT</span> </div> </div> <p class="title is-5 mathjax"> Beamforming Optimization for Active RIS-Aided Multiuser Communications With Hardware Impairments </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Peng%2C+Z">Zhangjie Peng</a>, <a href="/search/eess?searchtype=author&query=Zhang%2C+Z">Zhibo Zhang</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Di+Renzo%2C+M">Marco Di Renzo</a>, <a href="/search/eess?searchtype=author&query=Dobre%2C+O+A">Octavia A. Dobre</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+J">Jiangzhou Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2402.10687v1-abstract-short" style="display: inline;"> In this paper, we consider an active reconfigurable intelligent surface (RIS) to assist the multiuser downlink transmission in the presence of practical hardware impairments (HWIs), including the HWIs at the transceivers and the phase noise at the active RIS. The active RIS is deployed to amplify the incident signals to alleviate the multiplicative fading effect, which is a limitation in the conve… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.10687v1-abstract-full').style.display = 'inline'; document.getElementById('2402.10687v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2402.10687v1-abstract-full" style="display: none;"> In this paper, we consider an active reconfigurable intelligent surface (RIS) to assist the multiuser downlink transmission in the presence of practical hardware impairments (HWIs), including the HWIs at the transceivers and the phase noise at the active RIS. The active RIS is deployed to amplify the incident signals to alleviate the multiplicative fading effect, which is a limitation in the conventional passive RIS-aided wireless systems. We aim to maximize the sum rate through jointly designing the transmit beamforming at the base station (BS), the amplification factors and the phase shifts at the active RIS. To tackle this challenging optimization problem effectively, we decouple it into two tractable subproblems. Subsequently, each subproblem is transformed into a second order cone programming problem. The block coordinate descent framework is applied to tackle them, where the transmit beamforming and the reflection coefficients are alternately designed. In addition, another efficient algorithm is presented to reduce the computational complexity. Specifically, by exploiting the majorization-minimization approach, each subproblem is reformulated into a tractable surrogate problem, whose closed-form solutions are obtained by Lagrange dual decomposition approach and element-wise alternating sequential optimization method. Simulation results validate the effectiveness of our developed algorithms, and reveal that the HWIs significantly limit the system performance of active RIS-empowered wireless communications. Furthermore, the active RIS noticeably boosts the sum rate under the same total power budget, compared with the passive RIS. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.10687v1-abstract-full').style.display = 'none'; document.getElementById('2402.10687v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 February, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">16 pages, 8 figures, accepted by IEEE Transactions on Wireless Communications</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2402.05847">arXiv:2402.05847</a> <span> [<a href="https://arxiv.org/pdf/2402.05847">pdf</a>, <a href="https://arxiv.org/format/2402.05847">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Reconfigurable Intelligent Surface-Aided Dual-Function Radar and Communication Systems With MU-MIMO Communication </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Jin%2C+Y">Yasheng Jin</a>, <a href="/search/eess?searchtype=author&query=Ren%2C+H">Hong Ren</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Yu%2C+Z">Zhiyuan Yu</a>, <a href="/search/eess?searchtype=author&query=Weng%2C+R">Ruisong Weng</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+B">Boshi Wang</a>, <a href="/search/eess?searchtype=author&query=Zhou%2C+G">Gui Zhou</a>, <a href="/search/eess?searchtype=author&query=He%2C+Y">Yongchao He</a>, <a href="/search/eess?searchtype=author&query=Elkashlan%2C+M">Maged Elkashlan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2402.05847v1-abstract-short" style="display: inline;"> In this paper, we investigate an reconfigurable intelligent surface (RIS)-aided integrated sensing and communication (ISAC) system. Our objective is to maximize the achievable sum rate of the multi-antenna communication users through the joint active and passive beamforming. {Specifically}, the weighted minimum mean-square error (WMMSE) method is { first} used to reformulate the original problem i… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.05847v1-abstract-full').style.display = 'inline'; document.getElementById('2402.05847v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2402.05847v1-abstract-full" style="display: none;"> In this paper, we investigate an reconfigurable intelligent surface (RIS)-aided integrated sensing and communication (ISAC) system. Our objective is to maximize the achievable sum rate of the multi-antenna communication users through the joint active and passive beamforming. {Specifically}, the weighted minimum mean-square error (WMMSE) method is { first} used to reformulate the original problem into an equivalent one. Then, we utilize an alternating optimization (AO) { algorithm} to decouple the optimization variables and decompose this challenging problem into two subproblems. Given reflecting coefficients, a penalty-based algorithm is utilized to deal with the non-convex radar signal-to-noise ratio (SNR) constraints. For the given beamforming matrix of the BS, we apply majorization-minimization (MM) to transform the problem into a quadratic constraint quadratic programming (QCQP) problem, which is ultimately solved using a semidefinite relaxation (SDR)-based algorithm. Simulation results illustrate the advantage of deploying RIS in the considered multi-user MIMO (MU-MIMO) ISAC systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.05847v1-abstract-full').style.display = 'none'; document.getElementById('2402.05847v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 February, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2402.04532">arXiv:2402.04532</a> <span> [<a href="https://arxiv.org/pdf/2402.04532">pdf</a>, <a href="https://arxiv.org/format/2402.04532">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> Joint Beamforming Design for Double Active RIS-assisted Radar-Communication Coexistence Systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Liu%2C+M">Mengyu Liu</a>, <a href="/search/eess?searchtype=author&query=Ren%2C+H">Hong Ren</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Wang%2C+B">Boshi Wang</a>, <a href="/search/eess?searchtype=author&query=Yu%2C+Z">Zhiyuan Yu</a>, <a href="/search/eess?searchtype=author&query=Weng%2C+R">Ruisong Weng</a>, <a href="/search/eess?searchtype=author&query=Zhi%2C+K">Kangda Zhi</a>, <a href="/search/eess?searchtype=author&query=He%2C+Y">Yongchao He</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2402.04532v1-abstract-short" style="display: inline;"> Integrated sensing and communication (ISAC) technology has been considered as one of the key candidate technologies in the next-generation wireless communication systems. However, when radar and communication equipment coexist in the same system, i.e. radar-communication coexistence (RCC), the interference from communication systems to radar can be large and cannot be ignored. Recently, reconfigur… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.04532v1-abstract-full').style.display = 'inline'; document.getElementById('2402.04532v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2402.04532v1-abstract-full" style="display: none;"> Integrated sensing and communication (ISAC) technology has been considered as one of the key candidate technologies in the next-generation wireless communication systems. However, when radar and communication equipment coexist in the same system, i.e. radar-communication coexistence (RCC), the interference from communication systems to radar can be large and cannot be ignored. Recently, reconfigurable intelligent surface (RIS) has been introduced into RCC systems to reduce the interference. However, the "multiplicative fading" effect introduced by passive RIS limits its performance. To tackle this issue, we consider a double active RIS-assisted RCC system, which focuses on the design of the radar's beamforming vector and the active RISs' reflecting coefficient matrices, to maximize the achievable data rate of the communication system. The considered system needs to meet the radar detection constraint and the power budgets at the radar and the RISs. Since the problem is non-convex, we propose an algorithm based on the penalty dual decomposition (PDD) framework. Specifically, we initially introduce auxiliary variables to reformulate the coupled variables into equation constraints and incorporate these constraints into the objective function through the PDD framework. Then, we decouple the equivalent problem into several subproblems by invoking the block coordinate descent (BCD) method. Furthermore, we employ the Lagrange dual method to alternately optimize these subproblems. Simulation results verify the effectiveness of the proposed algorithm. Furthermore, the results also show that under the same power budget, deploying double active RISs in RCC systems can achieve higher data rate than those with single active RIS and double passive RISs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.04532v1-abstract-full').style.display = 'none'; document.getElementById('2402.04532v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 February, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2402.02159">arXiv:2402.02159</a> <span> [<a href="https://arxiv.org/pdf/2402.02159">pdf</a>, <a href="https://arxiv.org/ps/2402.02159">ps</a>, <a href="https://arxiv.org/format/2402.02159">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Signal Processing">eess.SP</span> </div> </div> <p class="title is-5 mathjax"> FAS-assisted Wireless Powered Communication Systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/eess?searchtype=author&query=Lai%2C+X">Xiazhi Lai</a>, <a href="/search/eess?searchtype=author&query=Zhi%2C+K">Kangda Zhi</a>, <a href="/search/eess?searchtype=author&query=Li%2C+W">Wanyi Li</a>, <a href="/search/eess?searchtype=author&query=Wu%2C+T">Tuo Wu</a>, <a href="/search/eess?searchtype=author&query=Pan%2C+C">Cunhua Pan</a>, <a href="/search/eess?searchtype=author&query=Elkashlan%2C+M">Maged Elkashlan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2402.02159v1-abstract-short" style="display: inline;"> Fluid Antenna System (FAS) is recognized as a promising technology for enhancing communication performance. In this context, we explored the potential of FAS-assisted wireless powered communication systems. Specifically, the transmitter, equipped with FAS, harvests the radio frequency (RF) signal from a power beacon and utilizes the harvested energy for data transmission to the receiver. To evalua… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.02159v1-abstract-full').style.display = 'inline'; document.getElementById('2402.02159v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2402.02159v1-abstract-full" style="display: none;"> Fluid Antenna System (FAS) is recognized as a promising technology for enhancing communication performance. In this context, we explored the potential of FAS-assisted wireless powered communication systems. Specifically, the transmitter, equipped with FAS, harvests the radio frequency (RF) signal from a power beacon and utilizes the harvested energy for data transmission to the receiver. To evaluate the performance of the considered systems, we derive both the analytical and asymptotic expressions of the outage probability. Simulation results indicate that the diversity of the considered network closely aligns with the number of ports. Besides, it is also revealed that the port selection criteria based solely on single-hop configurations yield a diversity order of only one. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.02159v1-abstract-full').style.display = 'none'; document.getElementById('2402.02159v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 3 February, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2024. </p> </li> </ol> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous is-invisible">Previous </a> <a href="/search/?searchtype=author&query=Pan%2C+C&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Pan%2C+C&start=0" 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