Subcarrier Coupling and Scheduling for Multi-User OFDMA Relaying Networks

The performance of subcarrier coupling and its effects on different scheduling schemes in multi-user OFDMA relaying networks are investigated in this paper. The relay station adopts the amplify-and-forward (AF) relaying strategy and is allowed to couple an input subcarrier to another output subcarrier. We show that in a source-relay-destination model, subcarrier coupling can achieve substantial capacity gain only when the two hop links have similar channel qualities, and the achievable gain also depends on the slow-fading magnitude of either hop. In view of this, we employ a sub-optimal subcarrier coupling scheme with low complexity for the multi-user scenario. Simulation results demonstrate that the sub-optimal scheme achieve similar performance compared to the conventionally optimal scheme.