Performance analysis and optimization for cellular two-way relay networks with cooperative NOMA transmission

This paper proposes a cooperative non-orthogonal multiple access (NOMA) based two-way transmission scheme for a two-user cellular system, in which a base station (BS) exchanges information with a directlink user and an indirect link user. With superimposition coding, physical-layer network coding (PLNC) and successive interference cancellation, the BS and the two users are able to exchange messages within three time slots. We derive the sum-rate upper bound of the proposed scheme and investigate the optimal time and power allocations to maximize the sum-rate bound. Numerical results demonstrate that the derived bound is tight and the proposed scheme can improve the sum-rates significantly as compared with existing NOMA-based schemes.(c) 2022 The Authors. Published by Elsevier B.V. on behalf of The Korean Institute of Communications and Information Sciences. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).