Compute-and-Forward Two-Way Relaying

TL;DR

This paper introduces a compute-and-forward based two-way relaying scheme with relay selection, improving throughput and outage performance over traditional methods, especially with feedback capabilities across various SNR levels.

Contribution

It proposes a novel two-way relaying scheme using compute-and-forward and relay selection, deriving bounds and analyzing performance with and without feedback.

Findings

A-CMF scheme achieves the upper bound at all SNRs.

Both schemes approach the outage probability lower bound.

M-CMF reaches the upper bound only at low SNRs.

Abstract

In this paper, a new two-way relaying scheme based on compute-and-forward (CMF) framework and relay selection strategies is proposed, which provides a higher throughput than the conventional two-way relaying schemes. Two cases of relays with or without feedback transmission capability are considered. An upper bound on the computation rate of each relay is derived, and based on that, a lower bound on the outage probability of the system is presented assuming block Rayleigh fading channels. Numerical results show that while the average sum rate of the system without feedback, named as Max Compute-and-Forward (M-CMF), reaches the derived upper bound only in low SNRs, that of the system with feedback, named as Aligned Compute-and-Forward (A-CMF) reaches the bound in all SNRs. However, both schemes approach the derived lower bound on the outage probability in all SNRs.