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Multi-user MIMO

About: Multi-user MIMO is a research topic. Over the lifetime, 10265 publications have been published within this topic receiving 227206 citations. The topic is also known as: multi user mimo & MU-MIMO.


Papers
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Journal ArticleDOI
TL;DR: This paper considers the problem of interference control through the use of second-order statistics in massive MIMO multi-cell networks and characterizes the low-rankness of users' channel covariance matrices, as such a property can be exploited towards improved channel estimation as well as interference rejection via spatial filtering.
Abstract: This paper considers the problem of interference control through the use of second-order statistics in massive MIMO multi-cell networks. We consider both the cases of co-located massive arrays and large-scale distributed antenna settings. We are interested in characterizing the low-rankness of users' channel covariance matrices, as such a property can be exploited towards improved channel estimation (so-called pilot decontamination) as well as interference rejection via spatial filtering. In previous work, it was shown that massive MIMO channel covariance matrices exhibit a useful finite-rank property that can be modeled via the angular spread of multipath at a MIMO uniform linear array. This paper extends this result to more general settings including certain non-uniform arrays, and more surprisingly, to two dimensional distributed large-scale arrays. In particular our model exhibits the dependence of the signal subspace's richness on the scattering radius around the user terminal, through a closed-form expression. The applications of the low-rankness covariance property to channel estimation's denoising and low-complexity interference filtering are highlighted.

113 citations

Journal ArticleDOI
TL;DR: Theoretical results on the effect of antenna mutual coupling (MC) on capacity of multiple-input multiple-output (MIMO) wireless channels are presented with particular emphasis on the case of high signal to noise ratio (SNR) scenario.
Abstract: Theoretical results on the effect of antenna mutual coupling (MC) on capacity of multiple-input multiple-output (MIMO) wireless channels are presented in this paper with particular emphasis on the case of high signal to noise ratio (SNR) scenario. Two cases are considered, 1- channel capacity variations due to MC effect on correlation properties and target average receive SNR and 2- channel capacity variations due to MC effect on correlation properties at fixed average receive SNR. It is shown that the effect of MC on MIMO channel capacity can be positive or negative depending on the propagation environment spatial correlation properties and the characteristics of the transmitter and receiver MC matrices. Conditions where MC has positive and negative effects on MIMO channel capacity in the two considered cases are identified. Numerical results for half wavelength dipole antenna supporting the theoretical observations are presented.

113 citations

Journal ArticleDOI
TL;DR: A novel hybrid channel estimation is proposed by separately estimating the angle information and the gain matrix, which could significantly save the training overhead and substantially improve the channel estimation accuracy compared with the conventional beamspace approach.
Abstract: This paper presents a new view of multi-user (MU) hybrid massive multiple-input and multiple-output (MIMO) systems from array signal processing perspective. We first show that the instantaneous channel vectors corresponding to different users are asymptotically orthogonal if the angles of arrival of users are different. We then decompose the channel matrix into an angle domain basis matrix and a gain matrix. The former can be formulated by steering vectors and the latter has the same size as the number of RF chains, which perfectly matches the structure of hybrid precoding. A novel hybrid channel estimation is proposed by separately estimating the angle information and the gain matrix, which could significantly save the training overhead and substantially improve the channel estimation accuracy compared with the conventional beamspace approach. Moreover, with the aid of the angle domain matrix, the MU massive MIMO system can be viewed as a type of non-orthogonal angle division multiple access to simultaneously serve multiple users at the same frequency band. Finally, the performance of the proposed scheme is validated by computer simulation results.

112 citations

BookDOI
24 Oct 2013
TL;DR: In this article, the authors unify two different technologies: parasitic antenna arrays driven via analogue circuits that control the electromagnetic waves generated by the antenna array; and MIMO technology for multi-antenna arrays, typically driven by digital techniques in the baseband domain.
Abstract: This book unites two different technologies: parasitic antenna arrays driven via analogue circuits that control the electromagnetic waves generated by the antenna array; and MIMO technology for multi-antenna arrays, typically driven by digital techniques in the baseband domain. The combination of these two technologies has revealed a novel functionality that breaks through the conventional MIMO paradigm, allowing MIMO transmission over the air with the use of antenna arrays that may consist of only a single active element, that is surrounded by a number of passive neighboring antennas. The contributions in the book show the capability of such systems to also perform MIMO transmission. This fact holds the potential of revolutionizing the way small-form wireless terminals operate and seems to set the scene for a win-win situation, achieving MIMO transmission with very small and cheap antenna arrays. The book is structured to provide a well-rounded treatment of the various facets of this newly discovered wireless communication capability. All relevant technical angles, ranging from information theoretic to electromagnetic considerations; from analogue circuit to digital baseband control for signal generation; and from channel modeling to communication theoretic aspects are taken into account. A good balance between theory, practical considerations and over-the-air experimentation is proposed and reflected in the chapter outline. Finally, a discussion and early evidence related to potential applications as well as the relevance to current and upcoming wireless standards is provided.

112 citations

Journal ArticleDOI
TL;DR: This paper presents a single- or multi-user Multiple-Input-Multiple-Output (MIMO) Full-Duplex (FD) precoding transceiver structure applicable for single-carrier and Orthogonal Frequency Division Multiplexing (OFDM) systems and shows that the FDP structure can provide very significant performance gains over existing techniques for both SU- and MU- MIMO systems.
Abstract: This paper presents a single- or multi-user Multiple-Input-Multiple-Output (MIMO) Full-Duplex (FD) precoding transceiver structure applicable for single-carrier and Orthogonal Frequency Division Multiplexing (OFDM) systems. The structure increases the dimensionality at the transmitter, which allow for the cancellation of self-interference and forward beamforming to be jointly processed using precoding at the transmitter. The FD Precoding (FDP) structure allows for various joint precoding algorithms and different optimization objectives. We present separate and joint precoding designs for sum-rate maximization and a theoretical analysis of when the separate design is optimal. The joint designs make use of Sequential Convex Programming (SCP). Extensive simulation results using both channel models and measured data show that the FDP structure can provide very significant performance gains over existing techniques for both SU- and MU-MIMO systems. In particular, the FDP structure provides between 1.6 and 1.8 times the spectral efficiency of optimized half-duplex for many of the tested SU-MIMO scenarios.

112 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202363
2022122
2021170
2020211
2019234
2018263