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.
@article{arxiv.1604.00787,
title = {Relay Selection for Cooperative NOMA},
author = {Zhiguo Ding and Huaiyu Dai and H. Vincent Poor},
journal= {arXiv preprint arXiv:1604.00787},
year = {2016}
}