Capacity Bounds and Power Allocation for the Wireless Relay Channel

This paper studies upper bounds and lower bounds on the outage capacity and ergodic capacity of a three-node wireless relay channel in a Rayleigh fading environment. We also take into account practical constraints on the transmission duplexing at the relay node and on the synchronization between the source node and the relay node. We find that the gap between the upper bounds and lower bounds is typically negligible. Compared to direct transmission and traditional multi-hop protocols, our results reveal that optimum relay channel signaling can significantly outperform multi-hop protocols, and that power allocation has a significant impact on performance.