Relay Selection for Cooperative NOMA

TL;DR

This paper proposes a two-stage relay selection strategy for cooperative NOMA that minimizes outage probability and maximizes diversity gain, outperforming conventional approaches and orthogonal multiple access.

Contribution

A novel two-stage relay selection scheme for cooperative NOMA that achieves optimal outage probability and diversity gain, improving performance over existing methods.

Findings

Two-stage relay selection minimizes outage probability.

The scheme achieves maximal diversity gain.

Performance surpasses conventional max-min and orthogonal multiple access.

Abstract

This letter studies the impact of relay selection (RS) on the performance of cooperative non-orthogonal multiple access (NOMA). In particular, a two-stage RS strategy is proposed, and analytical results are developed to demonstrate that this two-stage strategy can achieve the minimal outage probability among all possible RS schemes, and realize the maximal diversity gain. The provided simulation results show that cooperative NOMA with this two-stage RS scheme outperforms that with the conventional max-min approach, and can also yield a significant performance gain over orthogonal multiple access.