A spectral efficient multi-mode relaying technique

Cooperative relaying with Distributed Space-Time Coding (DSTC) and cooperative Opportunistic Relaying (OR) are the two main relaying techniques that are typically employed in current wireless systems. However, OR is less complex and proven to be outage optimal compared to DSTC. Thus, in this paper we propose a Multi-Mode Relaying (MMR) technique that is based on OR and combined with the Successive Relaying (SR) technique in order to deal with the half-duplex constraint of the relay nodes. MMR, by employing Multi-Mode Decode-and-Forward (MMDF) relay nodes and incorporating two interference mitigation algorithms, not only combines the merits of OR and SR but also is able to alleviate the increased inter-relay interference caused by SR. The performance of MMR is evaluated through simulation and the results show that it is able to increase the average end-to-end capacity of the wireless path as well as the percentage of high quality packets received at the terminal of the user.