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We investigate a reconfigurable intelligent surface (RIS)-aided multi-user massive multiple-input multi-output (MIMO) system where low-resolution digital-analog converters (DACs) are configured at the base station (BS) in order to reduce…

Information Theory · Computer Science 2021-08-24 Jianxin Dai , Yuanyuan Wang , Cunhua Pan , Kangda Zhi , Hong Ren , Kezhi Wang

In this paper, we investigate the performance of multiple-input multiple-output (MIMO) fading channels assisted by a reconfigurable intelligent surface (RIS), through the employment of partition-based RIS schemes. The proposed schemes are…

Information Theory · Computer Science 2023-05-09 Andreas Nicolaides , Constantinos Psomas , Ghassan M. Kraidy , Sheng Yang , Ioannis Krikidis

This paper presents an asymptotic analysis of Multiple-Input Multiple-Output (MIMO) systems assisted by a 1-bit Reconfigurable Intelligent Surface (RIS) under Ricean fading conditions. Using random matrix theory, we show that, in the…

Signal Processing · Electrical Eng. & Systems 2025-11-12 Panagiotis Gavriilidis , Kyriakos Stylianopoulos , George C. Alexandropoulos

Downlink reconfigurable intelligent surface (RIS)-assisted multi-input-multi-output (MIMO) systems are considered with far-field, near-field, and hybrid-far-near-field channels. According to the angular or distance information contained in…

Information Theory · Computer Science 2023-10-03 Suyu Lv , Yuanwei Liu , Xiaodong Xu , Arumugam Nallanathan , A. Lee Swindlehurst

In this paper, we consider a reconfigurable intelligent surface (RIS)-assisted multiple-input multiple-output communication system with multiple antennas at both the base station (BS) and the user. We plan to maximize the achievable rate…

Information Theory · Computer Science 2024-05-28 Yaqiong Zhao , Jindan Xu , Wei Xu , Kezhi Wang , Xinquan Ye , Chau Yuen , Xiaohu You

In this paper, we consider a reconfigurable intelligence surface (RIS) aided uplink multiuser multi-input multi-output (MIMO) orthogonal frequency division multiplexing (OFDM) system, where the receiver is assumed to conduct low-complexity…

Information Theory · Computer Science 2022-08-31 Mingyang Yue , Lei Liu , Xiaojun Yuan

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

The fundamental problem of our interest here is soft-input soft-output multiple-input multiple-output (MIMO) detection. We propose a method, referred to as subspace marginalization with interference suppression (SUMIS), that yields…

Information Theory · Computer Science 2014-02-03 Mirsad Čirkić , Erik G. Larsson

Cell-free massive multiple-input multiple-output (MIMO) and reconfigurable intelligent surfaces (RISs) are two potential sixth-generation (6G) technologies. However, channel aging due to user mobility and electromagnetic interference (EMI)…

Information Theory · Computer Science 2025-02-27 Jun Qian , Chi Zhang , Ross Murch , Khaled B. Letaief

This paper investigates the downlink power allocation of the simultaneous transmitting and reflecting reconfigurable intelligent surface (STAR-RIS)-assisted cell-free massive multiple-input multiple-output (MIMO) system with multi-antenna…

Information Theory · Computer Science 2025-12-23 Jun Qian , Ross Murch , Khaled B. Letaief

This study focuses on the optimization of a single-cell multi-user multiple-input multiple-output (MIMO) system with multiple large-size reconfigurable intelligent surfaces (RISs). The overall transmit power is minimized by optimizing the…

Information Theory · Computer Science 2024-10-08 Silvia Palmucci , Giulio Bartoli , Andrea Abrardo , Marco Moretti , Marco Di Renzo

It is a challenging problem to jointly optimize the base station (BS) precoding matrix and the reconfigurable intelligent surface (RIS) phases simultaneously in a RIS-assisted multiple-user multiple-input-multiple-output (MU-MIMO) scenario…

Systems and Control · Electrical Eng. & Systems 2025-06-16 Zhi Chai , Jiajie Xu , Justin P Coon , Mohamed-Slim Alouini

In this paper, we study surface-based communication systems based on different levels of channel state information for system optimization. We analyze the system performance in terms of rate and degrees of freedom (DoF). We show that the…

For downlink massive multiple-input multiple-output (MIMO) operating in time-division duplex protocol, users can decode the signals effectively by only utilizing the channel statistics as long as channel hardening holds. However, in a…

Information Theory · Computer Science 2022-05-17 Tung T. Vu , Trinh Van Chien , Canh T. Dinh , Hien Quoc Ngo , Michail Matthaiou

This paper considers a multi-user multiple-input multiple-output (MU-MIMO) system where the downlink communication between a base station (BS) and multiple user equipments (UEs) is aided by a reconfigurable intelligent surface (RIS). We…

Signal Processing · Electrical Eng. & Systems 2024-09-24 Parisa Ramezani , Yasaman Khorsandmanesh , Emil Björnson

This letter investigates the secure communication in a reconfigurable intelligent surface (RIS)-aided multiuser massive multiple-input multiple-output (MIMO) system exploiting artificial noise (AN). We first derive a closed-form expression…

Information Theory · Computer Science 2023-01-11 Dan Yang , Jindan Xu , Wei Xu , Yongming Huang , Zhaohua Lu

Antenna selection is capable of reducing the hardware complexity of massive multiple-input multiple-output (MIMO) networks at the cost of certain performance degradation. Reconfigurable intelligent surface (RIS) has emerged as a…

Information Theory · Computer Science 2020-09-17 Jinglian He , Kaiqiang Yu , Yuanming Shi , Yong Zhou , Wei Chen , Khaled B. Letaief

This paper investigates the problem of resource allocation for multiuser communication networks with a reconfigurable intelligent surface (RIS)-assisted wireless transmitter. In this network, the sum transmit power of the network is…

Signal Processing · Electrical Eng. & Systems 2020-09-25 Zhaohui Yang , Wei Xu , Chongwen Huang , Jianfeng Shi , Mohammad Shikh-Bahaei

This paper proposes a two-stage approach for passive and active beamforming in multiple-input multiple-output (MIMO) interference channels (ICs) assisted by a beyond-diagonal reconfigurable intelligent surface (BD-RIS). In the first stage,…

Information Theory · Computer Science 2025-03-26 Ignacio Santamaria , Mohammad Soleymani , Eduard Jorswieck , Jesus Gutierrez

Reconfigurable intelligent surface (RIS) is a promising candidate technology for the upcoming Sixth Generation (6G) communication system for its ability to manipulate the wireless communication environment by controlling the coefficients of…

Information Theory · Computer Science 2023-09-29 Haochen Li , Zhiwen Pan , Bin Wang , Nan Liu , Xiaohu You