Half-Duplex Relay-Help Transmission with Dirty Paper Coding

In this paper, we consider a half-duplex relay channel where the relay node cannot transmit and receive simultaneously. The information to be transmitted at the source node is composed of relayed information and non-relayed information. They interfere with each other in the existing scheme when the relay node forwards the relayed information and simultaneously the source node transmits the non-relayed information. In order to improve the transmission reliability, we propose two schemes where the source node chooses the non-relayed information codeword in terms of dirty paper coding (DPC). In Scheme 1, DPC technique is applied during the listening phase; and in Scheme 2, DPC technique is applied during the cooperative phase. Specially, we discuss the capacity behaviors of the proposed schemes and compare them with the baseline, namely the capacity behaviors of the existing scheme without the application of DPC technique. The corresponding numerical results prove that both proposed schemes outperform the existing scheme in the sense of capacity performance.