Parallel Retransmissions in Orthogonal Multiple Access Multiple Relay Networks

In this paper, we propose a novel selection strategy for the orthogonal Multiple Access Multiple Relay Networks (MAMRN). Rather than selecting a single relaying node to help one source node at a given retransmission time slot, we propose allocating one source to be helped by multiple relaying nodes. The idea is to exploit the multipath diversity of the different relaying nodes in order to optimize the spectral efficiency. We present the control exchange process in the novel selection strategy and we compare it to that of the prior art. In addition, we investigate the effect of equal gain combining on the performance, as well as the effect of the rates and the channel configuration. The numerical results show that the proposed strategy outperforms the prior art by exploiting the power budget available at each relaying node included in the system.