Optimal SNR-based selection relaying scheme in multi-relay cooperative networks with distributed space–time coding

Abstract

Error propagation from the relay to the destination is a major drawback of digital relaying protocols that substantially diminishes the cooperative diversity gain of the system. Appropriately designed selection relaying schemes can effectively mitigate this phenomenon and improve the diversity order, especially when the source-relay channel state information (CSI) is not available at the destination. In this study, the authors investigate the SNR-based selection relaying scheme in a multi-relay cooperative network that employs the distributed space -time coding (DSTC) strategy. The authors present a closed-form expression for the end-toend bit error probability (BEP) of the system. It is demonstrated that the orthogonality of the space -time coded signals transmitted by the relays is not preserved under the error propagation from the relays to the destination and this gives rise to intersymbol interference at the destination. The SNR loss and intersymbol interference caused by the error propagation substantially diminish the diversity order of the system. The error propagation can be effectively mitigated by employing appropriate thresholds at the relays. The authors derive a closed-form expression for the optimal threshold that minimises the end-to-end BEP of the system. The authors also analyse the asymptotic behaviour of the BEP and demonstrate that by employing the optimal threshold the full diversity order is achieved. Furthermore, the authors propose a class of thresholds that are independent of the network geometry and also provide full diversity order. By employing these thresholds, each relay node can decide to forward or remain silent independent of other relay nodes.

Performance comparison of cooperative relay links with different relay processing strategies: Nakagami/Gamma approximation approaches

“…One type of cooperative communication systems is the relayassisted, where distributed mobile nodes, often referred to as relays, are employed for attaining cooperative diversity, in order to enhance the reliability of wireless communications [5,6]. The relay-assisted wireless communication systems have been investigated in the context of various relay protocols, which include amplify-and-forward (AF), decode-and-forward (DF), compress-and-forward (CF) protocols, etc.…”

“…The relay-assisted wireless communication systems have been investigated in the context of various relay protocols, which include amplify-and-forward (AF), decode-and-forward (DF), compress-and-forward (CF) protocols, etc. [5][6][7]. http://jwcn.eurasipjournals.com/content/2014/1/53 fading channels, when both the number of relays and the number of hops may take arbitrary values.…”

Performance of decode and forward MIMO relaying for wireless uplink

“…Relay assisted wireless communication has been widely studied [25][26][27][28][29][30][31][32][33][34][35][36][37][38]. [7][8][9] show the performance of relay using amplifying and forwarding.…”

“…[22][23][24] show the performance of relay having single antenna at source and destination but multiple antennas at relay. [25][26][27][28][29][30][31][32][33][34][35][36][37][38] show the performance of relay having multiple antennas at source, relay and destination. This paper investigate the performance of relay for uplink wireless communication where source is equipped with single transmit antenna, relay is equipped with multiple transmit and receive antennas and destination is equipped with multiple receive antennas.…”

A threshold-based opportunistic network coding method combining with compressive sensing in satellite environments

“…In spite of this, both of them can not make certain the correctness of the received packets. Recently, many researchers focused on the reliability of data transmission , yet [7] studies a simple scenario with two paths ,a direct path and a path with only a relay, and it only considers the source-destination SNR at the relay, [8] focuses on the multipath scenario with only two hops, both of them haven"t taken throughput into account.…”