A Novel Location Relay Selection Scheme for ALLIANCES

Allow improved access in the network via cooperation and energy savings (ALLIANCES) is a recently proposed cooperative random access protocol for wireless networks that capitalizes on the broadcast nature of the wireless channel. When a collision occurs, a set of nodes forms an alliance and retransmits the collision signal that they heard. The initial collision and retransmissions provide the diversity that is exploited to resolve collisions and, thus, attain high throughput. In this paper, we modify the original model to include node location information. We derive pair-wise error probability (PEP) under a Rayleigh flat-fading channel and a power-law attenuation environment. Based on the PEP analysis, we propose a location relay selection scheme that achieves significant bit-error-rate gains as compared to the random relay selection scheme in the original ALLIANCES.