Downlink Power Control in Massive MIMO Networks with Distributed Antenna Arrays

TL;DR

This paper explores downlink power control in massive MIMO networks with distributed antenna arrays, deriving spectral efficiency expressions and proposing a max-min power control algorithm to improve network fairness and sum spectral efficiency.

Contribution

It introduces a novel power control method tailored for distributed antenna array massive MIMO systems, enhancing fairness and overall spectral efficiency.

Findings

Max-min power control improves sum spectral efficiency.

Distributed antenna arrays cause unique propagation effects.

Proposed algorithm ensures uniform user quality of service.

Abstract

In this paper, we investigate downlink power control in massive multiple-input multiple-output (MIMO) networks with distributed antenna arrays. The base station (BS) in each cell consists of multiple antenna arrays, which are deployed in arbitrary locations within the cell. Due to the spatial separation between antenna arrays, the large-scale propagation effect is different from a user to different antenna arrays in a cell, which makes power control a challenging problem as compared to conventional massive MIMO. We assume that the BS in each cell obtains the channel estimates via uplink pilots. Based on the channel estimates, the BSs perform maximum ratio transmission for the downlink. We then derive a closed-form spectral efficiency (SE) expression, where the channels are subject to correlated fading. Utilizing the derived expression, we propose a max-min power control algorithm to ensure that each user in the network receives a uniform quality of service. Numerical results demonstrate that, for the network considered in this work, optimizing for max-min SE through the max-min power control improves the sum SE of the network as compared to equal power allocation.