An Energy-Efficient Framework for the Analysis of MIMO Slow Fading Channels

TL;DR

This paper introduces a new energy-efficiency metric for MIMO channels that accounts for finite block lengths, channel estimation, and total power consumption, optimizing pre-coding and power in different CSI scenarios.

Contribution

It proposes a comprehensive energy-efficiency metric for MIMO systems considering practical factors and derives optimal power and training time strategies under imperfect and no CSI conditions.

Findings

Optimal power tuning is complex but feasible.

Simple equations characterize optimal training time with no CSI.

Results support energy-efficient power control in multiuser networks.

Abstract

In this work, a new energy-efficiency performance metric is proposed for MIMO (multiple input multiple output) point-to-point systems. In contrast with related works on energy-efficiency, this metric translates the effects of using finite blocks for transmitting, using channel estimates at the transmitter and receiver, and considering the total power consumed by the transmitter instead of the radiated power only. The main objective pursued is to choose the best pre-coding matrix used at the transmitter in the following two scenarios~: 1) the one where imperfect channel state information (CSI) is available at the transmitter and receiver~; 2) the one where no CSI is available at the transmitter. In both scenarios, the problem of optimally tuning the total used power is shown to be non-trivial. In scenario 2), the optimal fraction of training time can be characterized by a simple equation. These results and others provided in the paper, along with the provided numerical analysis, show that the present work can therefore be used as a good basis for studying power control and resource allocation in energy-efficient multiuser networks.