Two-Path Successive Relaying Based on Non-Orthogonal Multiple Access With Partial CSI

This paper proposes a two-path successive relaying (TPSR) scheme based on power domain non-orthogonal multiple access (NOMA), in which instantaneous channel state information (CSI) of source-to-relay and relay-to-destination channels are not required. Successive interference cancellation is applied at the relay to eliminate the inter-relay interference. Owing to differential binary phase-shift keying (DBPSK) modulation with non-coherent detection, only partial CSI, i.e., channel distribution information is required for source-to-relay and relay-to-destination channels. The closed-form end-to-end bit error rate (BER) is derived and validated by the simulation. The proposed NOMA-TPSR scheme can approach the BER performance of half-duplex relaying, and improve the spectral efficiency significantly. The BER performance and the spectral efficiency of NOMA-TPSR outperform that of direct transmission and full-duplex relaying with residual self-interference exceeding a certain level.