Coordinated Multicast Precoding for Multi-Cell Massive MIMO Transmission Exploiting Statistical Channel State Information

Li You,Xiqi Gao,Xu Chen,Wenjin Wang

doi:10.3390/electronics7110338

Abstract

This paper considers coordinated multi-cell multicast precoding for massive multiple-input-multiple-output transmission where only statistical channel state information of all user terminals (UTs) in the coordinated network is known at the base stations (BSs). We adopt the sum of the achievable ergodic multicast rate as the design objective. We first show the optimal closed-form multicast signalling directions of each BS, which simplifies the coordinated multicast precoding problem into a coordinated beam domain power allocation problem. Via invoking the minorization-maximization framework, we then propose an iterative power allocation algorithm with guaranteed convergence to a stationary point. In addition, we derive the deterministic equivalent of the design objective to further reduce the optimization complexity via invoking the large-dimensional random matrix theory. Numerical results demonstrate the performance gain of the proposed coordinated approach over the conventional uncoordinated approach, especially for cell-edge UTs.

Highlights

In massive multiple-input-multiple-output (MIMO) systems, large numbers of antennas are equipped at the base stations (BSs) to enable simultaneous transmission for different user terminals (UTs) in the same time and frequency transmission resources
Motivated by the above practical considerations, we investigate coordinated multicast precoding for multi-cell massive MIMO transmission exploiting statistical channel state information (CSI) in this paper
With the design goal to maximize the sum of the achievable ergodic multicast rate in coordinated multi-cell massive MIMO multicast precoding, we show that it is optimal for each BS to transmit the multicast signals in the beam domain

Summary

Introduction

In massive multiple-input-multiple-output (MIMO) systems, large numbers of antennas are equipped at the base stations (BSs) to enable simultaneous transmission for different user terminals (UTs) in the same time and frequency transmission resources. Electronics 2018, 7, 338 coordinated multi-cell MIMO transmission will lead to a significant signalling overhead. It is of more practical interest to exploit statistical CSI for coordinated multi-cell massive MIMO transmission since statistical CSI varies much more slowly than instantaneous CSI. Motivated by the above practical considerations, we investigate coordinated multicast precoding for multi-cell massive MIMO transmission exploiting statistical CSI in this paper. With the design goal to maximize the sum of the achievable ergodic multicast rate in coordinated multi-cell massive MIMO multicast precoding, we show that it is optimal for each BS to transmit the multicast signals in the beam domain. We adopt [A]i,j , [A]i,: , and [A]:,j to denote the (i, j)th element, the ith row, and the jth column of the matrix A, respectively. We adopt diag {x} to denote the diagonal matrix with x along its main diagonal

System Model

Coordinated Multicast Transmission Design

Simulation Results

Conclusions