Full Diversity Distributed Coding for the Multiple Access Half-Duplex Relay Channel

In this paper, we investigate the benefit of joint network-channel (JNC) distributed coding for the semi-orthogonal multiple-access half-duplex relay channel. The sources are allowed to transmit simultaneously during the listening phase of the relay, while during the relay transmission phase, they are constrained to remain silent. In contrast with previous work, we introduce a general framework for the relaying function, based on a selective approach, which depends on the number of correctly decoded messages. We also study the conditions where the introduced relaying function ensure the full diversity at the destination. We describe in detail the structure of the encoders, JNC coding, and the joint multiuser receiver structure. For a given spectral efficiency, we show through simulations that our approach provides substantial coding and diversity gains compared to existing schemes.