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This paper investigates the performance of reconfigurable intelligent surface (RIS)-aided massive multiple-input multiple-output (MIMO) systems with direct links, and the phase shifts of the RIS are designed based on the statistical channel…

Information Theory · Computer Science 2021-02-16 Kangda Zhi , Cunhua Pan , Hong Ren , Kezhi Wang

In this paper, we investigate cell-free massive MIMO (CF-mMIMO) systems in which access points (APs) are equipped with fluid antennas (FAs) and develop a comprehensive framework for channel estimation, antenna port selection, and uplink…

Information Theory · Computer Science 2025-12-30 Maryam Olyaee , Giovanni Interdonato , Stefano Buzzi

Flat-fading channel models are usually invoked for analyzing the performance of massive spatial modulation multiple-input multiple-output (SM-MIMO) systems. However, in the context of broadband SM transmission, the severe…

Information Theory · Computer Science 2017-12-04 Yue Sun , Jintao Wang , Longzhuang He , Jian Song

In this paper, we study the uplink (UL) and downlink (DL) spectral efficiency (SE) of a cell-free massive multiple-input-multiple-output (MIMO) system with Rician fading channels. The phase of the line-of-sight (LoS) path is modeled as a…

Information Theory · Computer Science 2019-11-04 Özgecan Özdogan , Emil Björnson , Jiayi Zhang

We study the impact of imperfect line-of-sight (LoS) phase tracking on the uplink performance of cell-free massive MIMO networks. Unlike prior works that assume perfectly known or completely unknown phases, we consider a realistic regime…

Information Theory · Computer Science 2026-02-27 Noor Ul Ain , Lorenzo Miretti , Renato L. G. Cavalcante , Slawomir Stanczak

This paper investigates robust and secure multiuser multiple-input single-output (MISO) downlink communications assisted by a self-sustainable intelligent reflection surface (IRS), which can simultaneously reflect and harvest energy from…

Information Theory · Computer Science 2021-08-05 Shaokang Hu , Zhiqiang Wei , Yuanxin Cai , Chang Liu , Derrick Wing Kwan Ng , Jinhong Yuan

Reconfigurable intelligent surface (RIS) is a promising technology for future wireless communications due to its capability of optimizing the propagation environments. Nevertheless, in literature, there are few prototypes serving multiple…

Signal Processing · Electrical Eng. & Systems 2024-05-14 Zhibo Zhou , Haifan Yin , Li Tan , Ruikun Zhang , Kai Wang , Yingzhuang Liu

In this work, we address the energy efficiency (EE) maximization problem in a downlink communication system utilizing reconfigurable intelligent surface (RIS) in a multi-user massive multiple-input multiple-output (mMIMO) setup with…

Information Theory · Computer Science 2023-12-22 Wilson de Souza Junior , Taufik Abrao

This paper is concerned with the proportional fairness (PF) of the spectral efficiency (SE) maximization of uplinks in a cell-free (CF) massive multiple-input multiple-output (MIMO) system in which a large number of single-antenna access…

Information Theory · Computer Science 2021-10-18 Viet Quoc Pham , Ha Hoang Kha , Le Ty Khanh

This paper studies an integrated network design that boosts system capacity through cooperation between wireless access points (APs) and a satellite. By coherently combing the signals received by the central processing unit from the users…

Information Theory · Computer Science 2022-09-07 Trinh Van Chien , Eva Lagunas , Tiep M. Hoang , Symeon Chatzinotas , Björn Ottersten , Lajos Hanzo

Massive multiple-input multiple-output (MIMO) is a key technology for improving the spectral and energy efficiency in 5G-and-beyond wireless networks. For a tractable analysis, most of the previous works on Massive MIMO have been focused on…

Information Theory · Computer Science 2021-09-14 Trinh Van Chien , Hien Quoc Ngo , Symeon Chatzinotas , Björn Ottersten , Merouane Debbah

Reconfigurable intelligent surfaces (RIS) are capable of beneficially ameliorating the propagation environment by appropriately controlling the passive reflecting elements. To extend the coverage area, the concept of simultaneous…

Information Theory · Computer Science 2023-06-16 Qingchao Li , Mohammed El-Hajjar , Yanshi Sun , Ibrahim Hemadeh , Arman Shojaeifard , Yuanwei Liu , Lajos Hanzo

The robust beamforming design in multi-functional reconfigurable intelligent surface (MF-RIS) assisted wireless networks is investigated in this work, where the MF-RIS supports signal reflection, refraction, and amplification to address the…

Computational Engineering, Finance, and Science · Computer Science 2024-12-12 Ailing Zheng , Wanli Ni , Wen Wang , Hui Tian , Chau Yuen

In this paper, the problem of sum-rate maximization for an active reconfigurable intelligent surface (RIS) assisted downlink rate-splitting multiple access (RSMA) transmission system is studied. In the considered model, the active RIS is…

Information Theory · Computer Science 2023-01-31 Xinhao Li , Tao Wang , Haonan Tong , Zhaohui Yang , Yijie Mao , Changchuan Yin

This work addresses the problem of secrecy energy efficiency (SEE) maximization in RIS-aided wireless networks. The use of active and nearly-passive RISs are compared and their trade-off in terms of SEE is analyzed. Considering both perfect…

Optimization and Control · Mathematics 2025-07-11 Robert Kuku Fotock , Agbotiname Lucky Imoize , Alessio Zappone , Marco Di Renzo , Roberto Garello

Reconfigurable intelligent surfaces (RISs) have emerged as a candidate technology for future 6G networks. However, due to the "multiplicative fading" effect, the existing passive RISs only achieve a negligible capacity gain in environments…

Information Theory · Computer Science 2023-01-20 Zijian Zhang , Linglong Dai , Xibi Chen , Changhao Liu , Fan Yang , Robert Schober , H. Vincent Poor

Reconfigurable intelligent surfaces (RISs) have been introduced as a remedy for mitigating frequent blockages in millimeter wave (mmWave) multiple-input multiple-output (MIMO) communication networks. However, perfect or nearly perfect…

Signal Processing · Electrical Eng. & Systems 2021-06-22 Rafaela Schroeder , Jiguang He , Markku Juntti

This paper considers the uplink (UL) of a multi-cell Massive MIMO (multiple-input multiple-output) system with spatially correlated Rician fading channels. The channel model is composed of a deterministic line-of-sight (LoS) path and a…

Information Theory · Computer Science 2018-05-22 Özgecan Özdogan , Emil Björnson , Erik G. Larsson

Cell-free (CF) massive multiple-input multiple-output (MIMO) systems are expected to implement advanced cooperative communication techniques to let geographically distributed access points jointly serve user equipments. Building on the…

Information Theory · Computer Science 2022-01-25 Jiakang Zheng , Jiayi Zhang , Bo Ai

This work investigates a full-duplex (FD)-enhanced Rate-Splitting Multiple Access (RSMA) system under practical constraints, including imperfect channel state information (CSI) and successive interference cancellation (SIC). We derive…

Signal Processing · Electrical Eng. & Systems 2026-04-21 Farjam Karim , Nurul Huda Mahmood , Deepak Kumar , Arthur Sousa de Sena , Matti-Latva-aho