Giovanni Iacovelli, Claudio Iacovelli, Symeon Chatzinotas
{"title":"Holographic MIMO Surfaces: A Channel Model Approximation in the Electromagnetic Domain","authors":"Giovanni Iacovelli, Claudio Iacovelli, Symeon Chatzinotas","doi":"10.1109/lwc.2024.3498597","DOIUrl":"https://doi.org/10.1109/lwc.2024.3498597","url":null,"abstract":"","PeriodicalId":13343,"journal":{"name":"IEEE Wireless Communications Letters","volume":"128 1","pages":""},"PeriodicalIF":6.3,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142637254","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}
{"title":"mmAlert: mmWave Link Blockage Prediction via Passive Sensing","authors":"Chao Yu;Yifei Sun;Yan Luo;Rui Wang","doi":"10.1109/LWC.2023.3304320","DOIUrl":"10.1109/LWC.2023.3304320","url":null,"abstract":"In this letter, the mmAlert system, predicting millimeter wave (mmWave) link blockage during data communication, is elaborated and demonstrated. The passive sensing method is adopted for mobile blocker detection, where two receive beams with separated radio frequency (RF) chains are equipped at the data communication receiver. One receive beam is aligned to the direction of line-of-sight (LoS) path, and the other one periodically sweeps the region close to the LoS path. By comparing the signals received by the above two beams, the Doppler frequencies of the signal scattered from the mobile blocker can be detected. Furthermore, by tracking the Doppler frequencies and the angle-of-arrivals (AoAs) of the scattered signals, the trajectory of the mobile blocker can be estimated, such that the potential link blockage can be predicted by assuming consistent mobile velocity. It is demonstrated via experiments that the mmAlert system can always detect the motions of the walking person close to the LoS path, and predict 90% of the LoS blockage with sensing time of 1.4 seconds.","PeriodicalId":13343,"journal":{"name":"IEEE Wireless Communications Letters","volume":"12 12","pages":"2008-2012"},"PeriodicalIF":6.3,"publicationDate":"2023-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41268427","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}
Qiang Sun;Hongwu Liu;Shen Yan;Theodoros A. Tsiftsis;Jinhong Yuan
{"title":"Joint Receive and Passive Beamforming Optimization for RIS-Assisted Uplink RSMA Systems","authors":"Qiang Sun;Hongwu Liu;Shen Yan;Theodoros A. Tsiftsis;Jinhong Yuan","doi":"10.1109/LWC.2023.3266883","DOIUrl":"10.1109/LWC.2023.3266883","url":null,"abstract":"In this letter, we investigate the joint optimization of transmit power allocation and receive/passive beamforming in a reconfigurable intelligent surface (RIS)-assisted uplink two-user rate-splitting multiple access (RSMA) system. Aiming at maximizing the achievable rate of one user subject to another user’s quality of service (QoS) requirements, RIS is deployed to assist the uplink transmissions from both users to a multi-antenna base station (BS). We decouple the non-convex rate maximization problem into three sub-problems and propose an alternating optimization (AO) algorithm to optimize the receive/passive beamforming and transmit power allocation. A closed-form expression is derived for the sub-problem of transmit power allocation by using the optimal decoding order and the concave-convex fractional programming beamforming problems are converted to convex ones by using the Charnes-Cooper transform. Then, a penalty term approach is applied to effectively solve the rank-1 constrained beamforming subproblems. Simulation results verify that the proposed AO algorithm attains a higher achievable rate than the existing benchmark schemes.","PeriodicalId":13343,"journal":{"name":"IEEE Wireless Communications Letters","volume":"12 7","pages":"1204-1208"},"PeriodicalIF":6.3,"publicationDate":"2023-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41256277","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}
{"title":"Phase and 3-D Placement Optimization for Rate Enhancement in RIS-Assisted UAV Networks","authors":"Maham Misbah;Zeeshan Kaleem;Waqas Khalid;Chau Yuen;Abbas Jamalipour","doi":"10.1109/LWC.2023.3263224","DOIUrl":"10.1109/LWC.2023.3263224","url":null,"abstract":"In this letter, we aim at improving the system sum-rate performance of an assisted aerial base station (ABS) network by considering use of reconfigurable intelligent surface (RIS). We jointly optimize the RIS phase shifts and ABS altitudes using the proposed conjugate gradient and particle swarm optimization (CG-PSO) scheme. Moreover, we divide the problem into sub-problems and solve them using an alternative optimization method. First, an optimal RIS phase shift is computed using the conjugate gradient (CG) under the fixed ABS altitude and varying transmit power. Finally, we find the optimal ABS altitude using particle swarm optimization (PSO), which results in improved sum rate under the optimized RIS phase shift. The results show that the CG-PSO scheme significantly improves the system sum rate compared to the baseline schemes.","PeriodicalId":13343,"journal":{"name":"IEEE Wireless Communications Letters","volume":"12 7","pages":"1135-1138"},"PeriodicalIF":6.3,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41325903","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}
{"title":"Beamspace Modulation for Near Field Capacity Improvement in XL-MIMO Communications","authors":"Shuaishuai Guo;Kaiqian Qu","doi":"10.1109/LWC.2023.3277666","DOIUrl":"10.1109/LWC.2023.3277666","url":null,"abstract":"The spatial degrees of freedom (DoFs) greatly increase in the near-field region of millimeter wave or terahertz multiple-input multiple-output communications with extremely large antenna arrays (XL-MIMO). To employ the increased spatial DoFs, a beamspace modulation (BM) strategy is introduced to the near field of XL-MIMO. BM can work with a fixed small number of RF chains. It exploits the increased spatial DoFs as modulation resources for capacity improvements. The achievable spectral efficiency and its asymptotic capacity are analyzed. Both theoretical and simulation results show that the proposed BM strategy considerably outperforms the existing benchmark that only selects the best beamspace for data transmission in terms of spectral efficiency.","PeriodicalId":13343,"journal":{"name":"IEEE Wireless Communications Letters","volume":"12 8","pages":"1434-1438"},"PeriodicalIF":6.3,"publicationDate":"2023-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41491574","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}