A joint resource allocation scheme for multi-relay aided uplink multi-user OFDMA system

In this paper, we consider the problem of resource allocation in relay aided uplink multi-user transmission with a single destination node. We adopt the amplify-and-forward (AF) relaying scheme and the orthogonal frequency division multiple access (OFDMA) as the main transmission modulation. The optimization is formulated as maximizing the end-to-end system throughput subject to limited number of sub-carriers and a limited amount of power for each individual user as well as the relay node. The optimization is a mixed integer programming problem over the sub-carrier allocation to each user, sub-carrier pairing at the relay, the power allocation of each user, and the power allocation at the relay. With the aid of dual decomposition, we find the near optimal solutions with acceptable complexity. To further reduce the complexity, we present a suboptimal algorithm which sacrifices very little on the performance. Finally, simulation results are provided to corroborate the proposed studies.