Opportunities, Constraints, and Benefits of Relaying in the Presence of Interference

In this paper the interference channel is extended by additional relay nodes in order to investigate the influence of interference on the design and performance of relaying protocols. We introduce a framework in which the relay interference channel is decomposed into a cascade of individual interference channels with finite conference links at the transmitters. Each of these stages is able to implement interference cancellation and mitigation schemes such as dirty-paper and Han-Kobayashi coding. We discuss the dependencies between individual stages and propose specific approaches with reasonable complexity. Finally, we compare the performance of these protocols using a simplified model for the channel and network geometry of a mobile communications system. The results show that a reasonable choice is to coordinate the base-station to relay links using distributed dirty-paper coding and to mitigate interference on the relay to user link using Han-Kobayashi coding.