Novel Receiver Design for the Cooperative Relaying System With Non-Orthogonal Multiple Access

In this letter, a novel detection scheme for the cooperative relaying system using non-orthogonal multiple access (CRS-NOMA) is proposed. For CRS-NOMA, the source simultaneously transmits two symbols by employing the superposition code, and the relay decodes and forwards the symbol with lower allocated power by employing the successive interference cancellation (SIC). In the proposed scheme, the destination jointly decodes two symbols from both the directed signal and the forwarded signal by employing the maximum-ratio combination and another SIC. The ergodic sum rate and the outage performance of the system are investigated. A suboptimal allocation strategy is also designed. Both analysis and simulations reveal the advantages of the proposed scheme.