Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article Performance of Multiple-Relay Cooperative Diversity Systems with Best Relay Selection over Rayleigh Fading Channels | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2008 Article ID 580368 7 pages doi 2008 580368 Research Article Performance of Multiple-Relay Cooperative Diversity Systems with Best Relay Selection over Rayleigh Fading Channels Salama S. Ikki and Mohamed H. Ahmed Faculty of Engineering and Applied Science Memorial University St. John s Newfoundland and Labrador Canada A1B3X5 Correspondence should be addressed to Salama S. Ikki ikki@ Received 16 November 2007 Accepted 17 March 2008 Recommended by Andrea Conti We consider an amplify-and-forward AF cooperative diversity system where a source node communicates with a destination node directly and indirectly through multiple relays . In regular multiple-relay cooperative diversity systems all relay nodes relay the source signal using orthogonal channels time slots carriers or codes to avoid cochannel interference. Hence for a regular cooperative diversity network with M relays we need M 1 channels one for the direct link and M for the M indirect links . This means that the number of required channels increases linearly with the number of relays. In this paper we investigate the performance of the best-relay selection scheme where the best relay only participates in the relaying. Therefore two channels only are needed in this case one for the direct link and the other one for the best indirect link regardless of the number of relays M . The best relay is selected as the relay node that can achieve the highest signal-to-noise ratio SNR at the destination node. We show that the best-relay selection not only reduces the amount of required resources but also maintains a full diversity order which is achievable by the regular multiple-relay cooperative diversity system but with much more amount of resources . We derive closed form expressions for tight lower bounds of the symbol error probability and outage probability. Since it is hard to find a closed-form expression
