Massive MIMO with Optimal Power and Training Duration Allocation

TL;DR

This paper proposes an optimal resource allocation scheme for massive MIMO uplink systems that maximizes spectral efficiency by jointly optimizing training duration, training power, and data power, adapting to different SNR regimes.

Contribution

It introduces a novel joint optimization framework for training and power allocation in massive MIMO, demonstrating significant spectral efficiency gains.

Findings

Optimal training duration equals the number of terminals across all SNRs.

More training power is optimal at low SNRs, less at high SNRs.

Numerical results confirm the efficiency of the proposed scheme.

Abstract

We consider the uplink of massive multicell multiple-input multiple-output systems, where the base stations (BSs), equipped with massive arrays, serve simultaneously several terminals in the same frequency band. We assume that the BS estimates the channel from uplink training, and then uses the maximum ratio combining technique to detect the signals transmitted from all terminals in its own cell. We propose an optimal resource allocation scheme which jointly selects the training duration, training signal power, and data signal power in order to maximize the sum spectral efficiency, for a given total energy budget spent in a coherence interval. Numerical results verify the benefits of the optimal resource allocation scheme. Furthermore, we show that more training signal power should be used at low signal-to-noise ratio (SNRs), and vice versa at high SNRs. Interestingly, for the entire SNR regime, the optimal training duration is equal to the number of terminals.