On Exploiting Cooperative, Channel and Multiuser Diversities in Wireless Relay Networks

In this paper, we exploit cooperative diversity, channel diversity and multi-user diversity gains in an OFDMA-based wireless relay network by studying a joint channel and relay assignment problem. This problem turns out to be NP-hard. First, a mixed integer linear programming formulation is presented to provide optimal solutions. We then present a constant factor approximation algorithm and two heuristic algorithms to solve this problem in polynomial time. Extensive simulation results have been presented to justify the efficiency of the proposed algorithms.