Probabilistic relay assignment strategy for cooperation networks with random relays

A new approach in fairness is proposed by using a probabilistic relay assignment strategy for cooperative communication systems. In this approach, relays are allocated to sources based on a probabilistic relay assignment function, which is characterised by the outage probability. To examine the proposed relay assignment strategy, an exact expression for the outage probability of an opportunistic coded cooperation diversity system is derived. It is assumed that the relays in this system are distributed according to a two-dimensional homogeneous Poisson point process, and the transmission channels undergo Rayleigh fading as well as path loss. It is observed that the proposed strategy reduces the number of requests for using the relays and, thus, utilises the relays more efficiently. Furthermore, compared to the conventional opportunistic relay assignment strategy, the total power consumed by the relays decreases, while the quality of service requirements are still satisfied.