A Hybrid Relay Selection Scheme Using Differential Modulation

In this paper, we propose a hybrid relay selection (HRS) scheme in a general cooperative network using differential modulation. In the HRS scheme, when the destination decodes successfully, the relay nodes will remain silent. Otherwise, optimal relay node has to be determined to make an additional transmission. In this process, all the relays are divided into two groups, referred to as an amplify-and-forward (AAF) relay group and a decode-and-forward (DAF) relay group depending on whether they can decode correctly or not. The relay, which has the maximum signal-to-noise ratio (SNR) at the destination, will be selected from both AAF and DAF relay groups. Simulation results show that the proposed relay selection scheme significantly outperforms the conventional AAF selection in terms of both frame error rate (FER) and throughput, and these performance gains considerably grow as the number of relay nodes increases.