Performance Analysis for Training-Based Multi-Pair Two-Way Full-Duplex Relaying with Massive Antennas

TL;DR

This paper analyzes the performance of a multi-pair two-way full-duplex relaying system with massive antennas, proposing channel estimation methods and power allocation strategies to enhance sum rate and fairness.

Contribution

It introduces new channel estimation schemes and power allocation strategies for multi-pair full-duplex relaying with massive antennas, improving rate performance.

Findings

Approximate sum rate expression accurately predicts ergodic sum rate.

Composite CSI estimation reduces pilot overhead effectively.

Power allocation strategies improve sum rate and fairness.

Abstract

This paper considers a multi-pair two-way amplify-and-forward relaying system, where multiple pairs of full-duplex users are served via a full-duplex relay with massive antennas, and the relay adopts maximum-ratio combining/maximum-ratio transmission (MRC/MRT) processing. The orthogonal pilot scheme and the least square method are firstly exploited to estimate the channel state information (CSI). When the number of relay antennas is finite, we derive an approximate sum rate expression which is shown to be a good predictor of the ergodic sum rate, especially in large number of antennas. Then the corresponding achievable rate expression is obtained by adopting another pilot scheme which estimates the composite CSI for each user pair to reduce the pilot overhead of channel estimation. We analyze the achievable rates of the two pilot schemes and then show the relative merits of the two methods. Furthermore, power allocation strategies for users and the relay are proposed based on sum rate maximization and max-min fairness criterion, respectively. Finally, numerical results verify the accuracy of the analytical results and show the performance gains achieved by the proposed power allocation.