Tuyển tập các báo cáo nghiên cứu về hóa học được đăng trên tạp chí hóa hoc quốc tế đề tài : Relay selection in cooperative networks with frequency selective fading | Deng and Klein EURASIP Journal on Wireless Communications and Networking 2011 2011 171 http content 2011 1 171 D EURASIP Journal on Wireless Communications and Networking a springeropen Journal RESEARCH Open Access Relay selection in cooperative networks with frequency selective fading Qingxiong Deng and Andrew G Klein Abstract In this article we consider the diversity-multiplexing tradeoff DMT of relay-assisted communication through correlated frequency selective fading channels. Recent results for relays in flat fading channels demonstrate a performance and implementation advantage in using relay selection as opposed to more complicated distributed space-time coding schemes. Motivated by these results we explore the use of relay selection for the case when all channels have intersymbol interference. In particular we focus on the performance of relaying strategies when multiple decode-and-forward relays share a single channel orthogonal to the source. We derive the DMT for several relaying strategies best relay selection random relay selection and the case when all decoding relays participate. The best relay selection method selects the relay in the decoding set with the largest sum-squared relay-to-destination channel coefficients. This scheme can achieve the optimal DMT of the system under consideration and generally dominates the other two relaying strategies which do not always exploit the spatial diversity offered by the relays. Different from flat fading we found special cases when the three relaying strategies have the same DMT. We further present a transceiver design which is proven to asymptotically achieve the optimal DMT. Monte Carlo simulations are presented to corroborate the theoretical analysis and to provide a detailed performance comparison of the three relaying strategies in channels encountered in practice. Keywords cooperative communication relay selection opportunistic relaying diversity-multiplexing tradeoff outage .
