Pub Date : 2024-12-11DOI: 10.1109/LCOMM.2024.3515973
Zilong Wang;Chaojin Qing;Linsi He;Haowen Jiang;Yuqiao Yang;Yu Sun
Due to the limited transmission resources, as well as the limited computing resources and battery energy of user equipment (UE), the estimated downlink channel state information (CSI) is typically off-grid, deteriorating the channel sparsity and recovery accuracy of the downlink CSI at the base station (BS). To address these issues, we propose a sensing information-assisted CSI feedback method to recover the off-grid downlink CSI at the BS. Specifically, the proposed method utilizes the sensing information from distinct data modality to form the off-grid prior information. Subsequently, by leveraging the off-grid prior information and the received CSI, the complex path gain of the downlink CSI is recovered. Finally, a high resolution grid is constructed to recover the off-grid CSI matrix, thereby enhancing the recovery accuracy. Simulation results demonstrate that the proposed method effectively mitigates the off-grid effect of the downlink CSI at the BS. Furthermore, the proposed method presents performance improvement and robustness against parameter variations when compared to other methods.
{"title":"Sensing Information-Assisted CSI Feedback","authors":"Zilong Wang;Chaojin Qing;Linsi He;Haowen Jiang;Yuqiao Yang;Yu Sun","doi":"10.1109/LCOMM.2024.3515973","DOIUrl":"https://doi.org/10.1109/LCOMM.2024.3515973","url":null,"abstract":"Due to the limited transmission resources, as well as the limited computing resources and battery energy of user equipment (UE), the estimated downlink channel state information (CSI) is typically off-grid, deteriorating the channel sparsity and recovery accuracy of the downlink CSI at the base station (BS). To address these issues, we propose a sensing information-assisted CSI feedback method to recover the off-grid downlink CSI at the BS. Specifically, the proposed method utilizes the sensing information from distinct data modality to form the off-grid prior information. Subsequently, by leveraging the off-grid prior information and the received CSI, the complex path gain of the downlink CSI is recovered. Finally, a high resolution grid is constructed to recover the off-grid CSI matrix, thereby enhancing the recovery accuracy. Simulation results demonstrate that the proposed method effectively mitigates the off-grid effect of the downlink CSI at the BS. Furthermore, the proposed method presents performance improvement and robustness against parameter variations when compared to other methods.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 2","pages":"313-317"},"PeriodicalIF":3.7,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143403976","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Over-the-air computation (AirComp) reduces the latency of wireless data aggregation by leveraging the superposition property of the wireless channel to achieve the desired function. This letter proposes a physical layer security (PLS) technique based on cooperative beamforming (CB) and distributed null steering for an AirComp network to effectively prevent eavesdropping. We provide a theoretical framework to combine CB and AirComp with adaptive null steering to degrade the reception of an eavesdropper located near the legitimate receiver. A closed-form expression for the average mean squared error (MSE) is derived, showing that the proposed distributed null-steering beamforming provides significantly better PLS performance than analog cooperative beamforming. Furthermore, a genetic algorithm is employed to jointly optimize the nulling factor and the direction to maximize the average MSE gap.
{"title":"Performance Analysis of Physical Layer Security for Over-the-Air Computation Using Distributed Null-Steering Beamforming","authors":"Usman Iqbal;Sunghwan Cho;Haejoon Jung;Mohsen Guizani","doi":"10.1109/LCOMM.2024.3515038","DOIUrl":"https://doi.org/10.1109/LCOMM.2024.3515038","url":null,"abstract":"Over-the-air computation (AirComp) reduces the latency of wireless data aggregation by leveraging the superposition property of the wireless channel to achieve the desired function. This letter proposes a physical layer security (PLS) technique based on cooperative beamforming (CB) and distributed null steering for an AirComp network to effectively prevent eavesdropping. We provide a theoretical framework to combine CB and AirComp with adaptive null steering to degrade the reception of an eavesdropper located near the legitimate receiver. A closed-form expression for the average mean squared error (MSE) is derived, showing that the proposed distributed null-steering beamforming provides significantly better PLS performance than analog cooperative beamforming. Furthermore, a genetic algorithm is employed to jointly optimize the nulling factor and the direction to maximize the average MSE gap.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 2","pages":"303-307"},"PeriodicalIF":3.7,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143403979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-09DOI: 10.1109/LCOMM.2024.3513934
Changyue Hu;Zhiyong Liu;Miao Ke;Qinyu Zhang
In this letter, we propose a frequency-domain improved proportionate normalized least mean square based sparse direct adaptive equalization (FD-IPNLMS-SDAE) algorithm for underwater acoustic communication. Compared with the existing methods, the proposed algorithm is implemented in the frequency domain, which not only significantly reduces the complexity, but also has the convergence performance advantage of the sparse algorithm. Simulation results verify the advantages of the proposed algorithm over the existing approaches.
{"title":"Frequency-Domain IPNLMS-Based Sparse Direct Adaptive Equalization for Underwater Acoustic Communications","authors":"Changyue Hu;Zhiyong Liu;Miao Ke;Qinyu Zhang","doi":"10.1109/LCOMM.2024.3513934","DOIUrl":"https://doi.org/10.1109/LCOMM.2024.3513934","url":null,"abstract":"In this letter, we propose a frequency-domain improved proportionate normalized least mean square based sparse direct adaptive equalization (FD-IPNLMS-SDAE) algorithm for underwater acoustic communication. Compared with the existing methods, the proposed algorithm is implemented in the frequency domain, which not only significantly reduces the complexity, but also has the convergence performance advantage of the sparse algorithm. Simulation results verify the advantages of the proposed algorithm over the existing approaches.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 2","pages":"289-293"},"PeriodicalIF":3.7,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143403995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-09DOI: 10.1109/LCOMM.2024.3512621
Anagha K. Kowshik;Sanjeev Gurugopinath;Sami Muhaidat
The growing number of connected devices in 6G networks requires advanced multiple access (MA) techniques and caching strategies to efficiently manage interference and enhance data rates. Caching offers a promising solution by storing frequently requested content at the network edge, reducing latency and alleviating backhaul congestion. Integrating caching with MA techniques is paramount for realizing the next-generation networks. Rate-splitting MA (RSMA) has emerged recently as a key candidate for future networks, due to its flexibility in managing interference and enhancing spectral efficiency. This paper presents a study on the performance of cache-aided RSMA (CA-RSMA) systems, which enhances the signal-to-noise-plus-interference (SINR) ratio. A multi-antenna equipped transmitter uses superposition coding, and two single-antenna equipped receivers use their cached content to remove the interference, which improves the SINR. We derive analytical expressions for key metrics, including probability of successful decoding (PSD), outage probability (OP), rate region and the weighted sum rate (WSR) for CA-RSMA. Furthermore, we formulate constrained optimization problems to maximize the PSD and WSR, in terms of the power allocation coefficients. Simulation results validate our analysis, and we show that CA-RSMA outperforms the conventional RSMA, non-orthogonal multiple access (NOMA), space-division multiple access, in terms of the considered metrics. A performance comparison shows that CA-RSMA outperforms CA-NOMA in terms of RR and WSR at an expense of PSD.
{"title":"Analysis and Strategies of Wireless Caching-Assisted Rate-Splitting Multiple Access","authors":"Anagha K. Kowshik;Sanjeev Gurugopinath;Sami Muhaidat","doi":"10.1109/LCOMM.2024.3512621","DOIUrl":"https://doi.org/10.1109/LCOMM.2024.3512621","url":null,"abstract":"The growing number of connected devices in 6G networks requires advanced multiple access (MA) techniques and caching strategies to efficiently manage interference and enhance data rates. Caching offers a promising solution by storing frequently requested content at the network edge, reducing latency and alleviating backhaul congestion. Integrating caching with MA techniques is paramount for realizing the next-generation networks. Rate-splitting MA (RSMA) has emerged recently as a key candidate for future networks, due to its flexibility in managing interference and enhancing spectral efficiency. This paper presents a study on the performance of cache-aided RSMA (CA-RSMA) systems, which enhances the signal-to-noise-plus-interference (SINR) ratio. A multi-antenna equipped transmitter uses superposition coding, and two single-antenna equipped receivers use their cached content to remove the interference, which improves the SINR. We derive analytical expressions for key metrics, including probability of successful decoding (PSD), outage probability (OP), rate region and the weighted sum rate (WSR) for CA-RSMA. Furthermore, we formulate constrained optimization problems to maximize the PSD and WSR, in terms of the power allocation coefficients. Simulation results validate our analysis, and we show that CA-RSMA outperforms the conventional RSMA, non-orthogonal multiple access (NOMA), space-division multiple access, in terms of the considered metrics. A performance comparison shows that CA-RSMA outperforms CA-NOMA in terms of RR and WSR at an expense of PSD.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 3","pages":"418-422"},"PeriodicalIF":3.7,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143594388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-09DOI: 10.1109/LCOMM.2024.3512537
Yangyang Zhang;Danyang Yu;Xichang Zhang;Yi Liu
In frequency division duplex (FDD) mode, the substantial feedback overhead in massive multi-input multi-output (MIMO) systems needs to be mitigated. Existing channel feedback methods that utilize channel temporal correlation exhibit limited performance under low compression ratios (CRs) or high-speed user equipment (UE) in the outdoor scenario. To address these challenges, we propose an autoregressive (AR) model-based differential framework incorporating a regularization learning network (RE-LENet) for channel state information (CSI) feedback in time-varying massive MIMO systems. The proposed AR model-based differential framework can capture the channel temporal correlation more effectively, reducing the degradation of channel reconstruction performance over time. We also design a convolutional neural network (CNN)-based RE-LENet to enhance the reconstruction performance of both the channel differential terms and the initial channel simultaneously. Numerical results indicate that the proposed CSI feedback framework outperforms existing methods.
{"title":"An Autoregressive Model-Based Differential Framework With Learnable Regularization for CSI Feedback in Time-Varying Massive MIMO Systems","authors":"Yangyang Zhang;Danyang Yu;Xichang Zhang;Yi Liu","doi":"10.1109/LCOMM.2024.3512537","DOIUrl":"https://doi.org/10.1109/LCOMM.2024.3512537","url":null,"abstract":"In frequency division duplex (FDD) mode, the substantial feedback overhead in massive multi-input multi-output (MIMO) systems needs to be mitigated. Existing channel feedback methods that utilize channel temporal correlation exhibit limited performance under low compression ratios (CRs) or high-speed user equipment (UE) in the outdoor scenario. To address these challenges, we propose an autoregressive (AR) model-based differential framework incorporating a regularization learning network (RE-LENet) for channel state information (CSI) feedback in time-varying massive MIMO systems. The proposed AR model-based differential framework can capture the channel temporal correlation more effectively, reducing the degradation of channel reconstruction performance over time. We also design a convolutional neural network (CNN)-based RE-LENet to enhance the reconstruction performance of both the channel differential terms and the initial channel simultaneously. Numerical results indicate that the proposed CSI feedback framework outperforms existing methods.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 1","pages":"230-234"},"PeriodicalIF":3.7,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142938363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Energy efficiency (EE) has become a key design metric for the sustainable development of future wireless communications. Dynamic metasurface antennas (DMAs), with their compact size and low power consumption, are considered a promising solution for improving EE. In this letter, we investigate the energy-efficient beamforming design for downlink multiple-input single-output communication systems, where the DMA-equipped base station serves multiple users simultaneously. We aim to maximize the energy efficiency by jointly optimizing the DMA weight matrix and the digital precoder, subject to the constraints of power budget and Lorentzian-phase. To address this complicated non-convex optimization problem, we develop an alternating optimization algorithm based on manifold optimization and sequential convex approximation. Numerical results verify the effectiveness of the proposed method.
{"title":"Energy-Efficient Beamforming for Downlink Multi-User Systems With Dynamic Metasurface Antennas","authors":"Guangyi Chen;Ruoyu Zhang;Haiyang Zhang;Chen Miao;Yue Ma;Wen Wu","doi":"10.1109/LCOMM.2024.3513554","DOIUrl":"https://doi.org/10.1109/LCOMM.2024.3513554","url":null,"abstract":"Energy efficiency (EE) has become a key design metric for the sustainable development of future wireless communications. Dynamic metasurface antennas (DMAs), with their compact size and low power consumption, are considered a promising solution for improving EE. In this letter, we investigate the energy-efficient beamforming design for downlink multiple-input single-output communication systems, where the DMA-equipped base station serves multiple users simultaneously. We aim to maximize the energy efficiency by jointly optimizing the DMA weight matrix and the digital precoder, subject to the constraints of power budget and Lorentzian-phase. To address this complicated non-convex optimization problem, we develop an alternating optimization algorithm based on manifold optimization and sequential convex approximation. Numerical results verify the effectiveness of the proposed method.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 2","pages":"284-288"},"PeriodicalIF":3.7,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143403962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This letter focuses on the pilot assignment problem in scalable cell-free systems and proposes a graph partitioning based scheme to improve the user fairness. Specifically, a novel metric to indicate the strength of potential pilot contamination between any two users is firstly defined, and a weighted graph is constructed by taking the novel defined metric as the edge weight to describe the potential interference among users. Then, we formulate the pilot assignment as a graph partitioning problem, and get the solution by the proposed degree sorting-based algorithm. Simulation results verify the effectiveness of the constructed metric to indicate the pilot contamination between users and the fairness advantage of the proposed algorithm.
{"title":"Graph Partitioning Based Pilot Assignment for Scalable Cell-Free Massive MIMO Systems","authors":"Zhirui Hu;Manyi Wang;Qing Liu;Yingbiao Yao;Zhiqiang Yi;Rong Zeng","doi":"10.1109/LCOMM.2024.3513455","DOIUrl":"https://doi.org/10.1109/LCOMM.2024.3513455","url":null,"abstract":"This letter focuses on the pilot assignment problem in scalable cell-free systems and proposes a graph partitioning based scheme to improve the user fairness. Specifically, a novel metric to indicate the strength of potential pilot contamination between any two users is firstly defined, and a weighted graph is constructed by taking the novel defined metric as the edge weight to describe the potential interference among users. Then, we formulate the pilot assignment as a graph partitioning problem, and get the solution by the proposed degree sorting-based algorithm. Simulation results verify the effectiveness of the constructed metric to indicate the pilot contamination between users and the fairness advantage of the proposed algorithm.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 2","pages":"279-283"},"PeriodicalIF":3.7,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143403981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-09DOI: 10.1109/LCOMM.2024.3512665
Santiago Fernández;J. Alfonso Bailón-Martínez;Juan E. Galeote-Cazorla;F. Javier López-Martínez
We introduce and characterize the operational diversity order (ODO) in fading channels, as a proxy to the classical notion of diversity order at any arbitrary operational signal-to-noise ratio (SNR). Thanks to this definition, relevant insights are brought up in a number of cases: 1) We quantify that in dominant line-of-sight scenarios an increased diversity order is attainable compared to that achieved asymptotically, even in the single-antenna case; 2) this effect is attenuated, but still visible, in the presence of an additional dominant specular component; 3) the decay slope in Rayleigh product channels increases very slowly, never fully achieving unitary slope for a finite SNR.
{"title":"Analytical Characterization of the Operational Diversity Order in Fading Channels","authors":"Santiago Fernández;J. Alfonso Bailón-Martínez;Juan E. Galeote-Cazorla;F. Javier López-Martínez","doi":"10.1109/LCOMM.2024.3512665","DOIUrl":"https://doi.org/10.1109/LCOMM.2024.3512665","url":null,"abstract":"We introduce and characterize the operational diversity order (ODO) in fading channels, as a proxy to the classical notion of diversity order at any arbitrary operational signal-to-noise ratio (SNR). Thanks to this definition, relevant insights are brought up in a number of cases: 1) We quantify that in dominant line-of-sight scenarios an increased diversity order is attainable compared to that achieved asymptotically, even in the single-antenna case; 2) this effect is attenuated, but still visible, in the presence of an additional dominant specular component; 3) the decay slope in Rayleigh product channels increases very slowly, never fully achieving unitary slope for a finite SNR.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 2","pages":"274-278"},"PeriodicalIF":3.7,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10781412","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143403999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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