Open Access

ARTICLE

An Enhanced Jacobi Precoder for Downlink Massive MIMO Systems

Park Chan-Yeob, Hyun-Ro Jae, Jun-Yong Jang, Song Hyoung-Kyu^*

Department of Information and Communication Engineering, and Convergence Engineering for Intelligent Drone, Sejong University, Seoul, 05006, Korea

* Corresponding Author: Song Hyoung-Kyu. Email:

Computers, Materials & Continua 2021, 68(1), 137-148. https://doi.org/10.32604/cmc.2021.016108

Received 23 December 2020; Accepted 26 January 2021; Issue published 22 March 2021

Abstract

Linear precoding methods such as zero-forcing (ZF) are near optimal for downlink massive multi-user multiple input multiple output (MIMO) systems due to their asymptotic channel property. However, as the number of users increases, the computational complexity of obtaining the inverse matrix of the gram matrix increases. For solving the computational complexity problem, this paper proposes an improved Jacobi (JC)-based precoder to improve error performance of the conventional JC in the downlink massive MIMO systems. The conventional JC was studied for solving the high computational complexity of the ZF algorithm and was able to achieve parallel implementation. However, the conventional JC has poor error performance when the number of users increases, which means that the diagonal dominance component of the gram matrix is reduced. In this paper, the preconditioning method is proposed to improve the error performance. Before executing the JC, the condition number of the linear equation and spectrum radius of the iteration matrix are reduced by multiplying the preconditioning matrix of the linear equation. To further reduce the condition number of the linear equation, this paper proposes a polynomial expansion precondition matrix that supplements diagonal components. The results show that the proposed method provides better performance than other iterative methods and has similar performance to the ZF.

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Keywords

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