Spectral efficient relaying protocols using interference cancelation in multiple relays environment

Abstract

In this paper, we propose two spectral efficient relaying protocols using interference cancelation (IC) and improved IC(IIC) in multiple decode-and-forward (DF) relays environment. In each phase, a source node broadcast its own data and one of the relay nodes having the largest effective channel is selected for forwarding the received data from the source node. The relay node that succeeds decoding the received data except for the selected relay node can cancel out a interference to decode new data without suffering from the interference caused by the selected relay node. Though the IC protocol outperforms other protocols in terms of average throughput in the paper, there is its performance tradeoff with the successive interference cancelation (SIC) protocol in terms of outage probability. In the IIC protocol, the relay nodes not in the decoding set performs SIC depending on the inter-relay channel condition while behaviors of the relay nodes in the decoding set are same as those in the IC protocol. The IIC protocol yields the best performance in terms of both outage probability and average throughput among protocols shown in the paper. The proposed protocols compensates for the loss of spectral efficiency caused by the relay nodes operating half duplex. Moreover, we analyze the performances of proposed protocols with Markov chain in steady state and confirm that our analysis is well-matched with simulations. Our numerical results show that the proposed protocols outperform the the other successive relaying protocols and opportunistic single relay selection scheme with DF in terms of both outage probability and average throughput.