Relay Channel with Orthogonal Components and Structured Interference Known at the Source

TL;DR

This paper investigates a relay channel affected by structured interference known only at the source, proposing strategies that leverage interference structure for improved communication in various channel models.

Contribution

It introduces novel transmission strategies based on partial decode-and-forward that exploit interference structure, with derived achievable schemes and optimal strategies in special cases.

Findings

Structured interference can be mitigated using source-informed relay strategies.

Numerical results demonstrate the benefits of exploiting interference structure.

Strategies are effective across discrete, Gaussian, and Ricean fading channels.

Abstract

A relay channel with orthogonal components that is affected by an interference signal that is noncausally available only at the source is studied. The interference signal has structure in that it is produced by another transmitter communicating with its own destination. Moreover, the interferer is not willing to adjust its communication strategy to minimize the interference. Knowledge of the interferer's signal may be acquired by the source, for instance, by exploiting HARQ retransmissions on the interferer's link. The source can then utilize the relay not only for communicating its own message, but also for cooperative interference mitigation at the destination by informing the relay about the interference signal. Proposed transmission strategies are based on partial decode-and-forward (PDF) relaying and leverage the interference structure. Achievable schemes are derived for discrete memoryless models, Gaussian and Ricean fading channels. Furthermore, optimal strategies are identified in some special cases. Finally, numerical results bring insight into the advantages of utilizing the interference structure at the source, relay or destination.