naa a22 4500 510795692 CHVBK 20180411083335.0 cr unu---uuuuu 180411e20130201xx s 000 0 eng 10.1007/s11277-011-0499-9 doi (NATIONALLICENCE)springer-10.1007/s11277-011-0499-9 Opportunistic Relaying for MIMO Amplify-and-Forward Cooperative Networks [Elektronische Daten] [Behrouz Maham, Are Hjørungnes] We consider a wireless relay network with multiple antenna terminals over Rayleigh fading channels, and apply distributed space-time coding (DSTC) in amplify-and-forward (A&F) mode. The A&F scheme is used in a way that each relay transmits a scaled version of the linear combination of the received symbols. It turns out that, combined with power allocation in the relays, A&F DSTC results in an opportunistic relaying scheme, in which only the best relay is selected to retransmit the source's space-time coded signal. Furthermore, assuming the knowledge of source-relay CSI at the source node, we design an efficient power allocation which outperforms uniform power allocation across the source antennas. Next, assuming M-PSK or M-QAM modulations, we analyze the performance of the proposed cooperative diversity transmission schemes in a wireless relay networks with the multiple-antenna source and destination. We derive the probability density function (PDF) of the received SNR at the destination. Then, the PDF is used to determine the symbol error rate (SER) in Rayleigh fading channels. We derived closed-form approximations of the average SER in the high SNR scenario, from which we find the diversity order of system R min{N s , N d }, where R, N s , and N d are the number of the relays, source antennas, and destination antennas, respectively. Simulation results show that the proposed system obtain more than 6 dB gain in SNR over A&F MIMO DSTC for BER 10−4, when R=2, N s =2, and N d =1. Springer Science+Business Media, LLC., 2012 Relay networks nationallicence Coopeative communications nationallicence Performance analysis nationallicence Maham Behrouz School of Electrical and Computer Engineering, College of Engineering, University of Tehran, Tehran, Iran aut Hjørungnes Are UNIK-University Graduate Center, University of Oslo, Kjeller, Norway aut Wireless Personal Communications Springer US; http://www.springer-ny.com 68/3(2013-02-01), 1067-1091 0929-6212 68:3<1067 2013 68 11277 https://doi.org/10.1007/s11277-011-0499-9 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11277-011-0499-9 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Maham Behrouz School of Electrical and Computer Engineering, College of Engineering, University of Tehran, Tehran, Iran aut NATIONALLICENCE 700 1- Hjørungnes Are UNIK-University Graduate Center, University of Oslo, Kjeller, Norway aut NATIONALLICENCE 773 0- Wireless Personal Communications Springer US; http://www.springer-ny.com 68/3(2013-02-01), 1067-1091 0929-6212 68:3<1067 2013 68 11277 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer