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We consider a cell-free massive multiple-input multiple-output (CF-mMIMO) system with joint unicast and multi-group multicast transmissions. We derive exact closed-form expressions for the downlink achievable spectral efficiency (SE) of…

Information Theory · Computer Science 2024-10-07 Mustafa S. Abbas , Zahra Mobini , Hien Quoc Ngo , Michail Matthaiou

Performance analysis is carried out in a near-field multiple-input multiple-output (MIMO) system for both discrete and continuous aperture antennas. The effective degrees of freedom (EDoF) is first derived. It is shown that near-field MIMO…

Information Theory · Computer Science 2023-10-03 Ziyi Xie , Yuanwei Liu , Jiaqi Xu , Xuanli Wu , Arumugam Nallanathan

A great amount of endeavor has recently been devoted to activity detection for massive machine-type communications in cell-free multiple-input multiple-output (MIMO) systems. However, as the number of antennas at the access points (APs)…

Signal Processing · Electrical Eng. & Systems 2026-05-27 Jingreng Lei , Yang Li , Ziyue Wang , Qingfeng Lin , Ya-Feng Liu , Yik-Chung Wu

Multiple-input multiple-output (MIMO) systems greatly increase the overall throughput of wireless systems since they are capable of transmitting multiple streams employing the same time-frequency resources. However, this gain requires an…

Information Theory · Computer Science 2022-02-15 A. Flores , R. C. de Lamare

Massive multi-input multi-output (MIMO) has evolved along two tracks: cellular and cell-free, each with unique advantages and limitations. The cellular approach suffers from worse user spectral efficiency at cell edges, whereas the…

Information Theory · Computer Science 2025-06-30 Wei Jiang , Hans D. Schotten

We consider a cell-free massive MIMO system with multiple antennas on the users and access points. In previous works, the downlink spectral efficiency (SE) has been evaluated using the hardening bound that requires no downlink pilots. This…

Signal Processing · Electrical Eng. & Systems 2024-04-30 Eren Berk Kama , Junbeom Kim , Emil Björnson

This paper investigates a multiple input single output (MISO) downlink communication system in which users are equipped with fluid antennas (FAs). First, we adopt a field-response based channel model to characterize the downlink channel…

Information Theory · Computer Science 2024-01-17 Haoran Qin , Wen Chen , Zhendong Li , Qingqing Wu , Nan Cheng , Fangjiong Chen

Cell-free Massive multiple-input multiple-output (MIMO) is considered, where distributed access points (APs) multiply the received signal by the conjugate of the estimated channel, and send back a quantized version of this weighted signal…

Information Theory · Computer Science 2019-07-09 Manijeh Bashar , Kanapathippillai Cumanan , Alister G. Burr , Hien Quoc Ngo , Merouane Debbah , Pei Xiao

We consider a practical cell-free massive multiple-input-multiple-output (MIMO) system with multi-antenna access points (APs) and spatially correlated Rician fading channels. The significant phase-shift of the line-of-sight component…

Information Theory · Computer Science 2021-10-13 Zhe Wang , Jiayi Zhang , Emil Björnson , Bo Ai

Modern 5G wireless cellular networks use massive multiple-input multiple-output (MIMO) technology. This concept entails using an antenna array at a base station to concurrently service many mobile devices that have several antennas on their…

Information Theory · Computer Science 2023-06-09 Evgeny Bobrov , Boris Chinyaev , Viktor Kuznetsov , Dmitrii Minenkov , Daniil Yudakov

Fluid antenna multiple access (FAMA) enables each user to rapidly switch among several closely spaced ports and select the strongest received signal. Although this mechanism offers micro-scale spatial diversity, its behavior in multiuser…

Information Theory · Computer Science 2026-05-25 Anastasios Papazafeiropoulos

Massive spatial modulation aided multiple-input multiple-output (SM-MIMO) systems have recently been proposed as a novel combination of spatial modulation (SM) and of conventional massive MIMO, where the base station (BS) is equipped with a…

Information Theory · Computer Science 2016-12-28 Longzhuang He , Jintao Wang , Jian Song , Lajos Hanzo

This letter analyzes the effects of power amplifiers (PAs) on the downlink of cell-free massive MIMO systems. We model signal transmission incorporating nonlinear PA distortion and derive a unified spectral efficiency (SE) expression…

Information Theory · Computer Science 2025-12-09 Wei Jiang , Hans D. Schotten

Cell-free networks leverage distributed access points (APs) to achieve macro-diversity, yet their performance is often constrained by large disparities in channel quality arising from user geometry and blockages. To address this, rotatable…

Signal Processing · Electrical Eng. & Systems 2026-05-07 Xingxiang Peng , Qingqing Wu , Ziyuan Zheng , Yanze Zhu , Wen Chen , Penghui Huang , Ying Gao , Honghao Wang

This letter proposes a multi-stream selection framework for \ac{CF-MIMO} networks. Partially coherent transmission has been considered by clustering \acp{AP} into phase-aligned clusters to address the challenges of phase misalignment and…

Signal Processing · Electrical Eng. & Systems 2025-06-09 Esra Aycan Beyazıt , Jeroen Famaey , Nina Slamnik-Kriještorac , Johann M. Marquez-Barja , Miguel Camelo Botero

MIMO mobile systems, with a large number of antennas at the base-station side, enable the concurrent transmission of multiple, spatially separated information streams and, therefore, enable improved network throughput and connectivity both…

Information Theory · Computer Science 2021-01-06 Konstantinos Nikitopoulos , Marcin Filo , Chathura Jayawardena , Rahim Tafazolli

The uplink of a wireless network with base stations distributed according to a Poisson Point Process (PPP) is analyzed. The base stations are assumed to have a large number of antennas and use linear minimum-mean-square-error (MMSE) spatial…

Information Theory · Computer Science 2013-11-20 Siddhartan Govindasamy

To meet the growing data traffic demand in future wireless systems, novel transmission architectures capable of adapting to complex propagation environments are required. Movable antenna (MA) systems have recently emerged as a promising…

Signal Processing · Electrical Eng. & Systems 2026-04-21 Xiaoyi Zhang , Amna Irshad , Emil Björnson

Large-scale multiple-input and multiple-output (MIMO) systems are capable of achieving high date rate. However, given the high hardware cost and excessive power consumption of massive MIMO systems, as a remedy, intelligent metasurfaces have…

Information Theory · Computer Science 2024-05-17 Qingchao Li , Mohammed El-Hajjar , Chao Xu , Jiancheng An , Chau Yuen , Lajos Hanzo

In this paper, we analyze both the rate of convergence and the performance of a matched-filter (MF) precoder in a massive multi-user (MU) multiple-input-multiple-output (MIMO) system, with the aim of determining the impact of distributing…

Information Theory · Computer Science 2015-03-04 Peter J. Smith , Callum T. Neil , Mansoor Shafi , Pawel A. Dmochowski