End-to-end performance of cooperative relaying in spectrum-sharing systems with quality of service requirements
KAUST DepartmentPhysical Sciences and Engineering (PSE) Division
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AbstractWe propose adopting a cooperative relaying technique in spectrum-sharing cognitive radio (CR) systems to more effectively and efficiently utilize available transmission resources, such as power, rate, and bandwidth, while adhering to the quality of service (QoS) requirements of the licensed (primary) users of the shared spectrum band. In particular, we first consider that the cognitive (secondary) user's communication is assisted by an intermediate relay that implements the decode-and-forward (DF) technique onto the secondary user's relayed signal to help with communication between the corresponding source and the destination nodes. In this context, we obtain first-order statistics pertaining to the first- and second-hop transmission channels, and then, we investigate the end-to-end performance of the proposed spectrum-sharing cooperative relaying system under resource constraints defined to assure that the primary QoS is unaffected. Specifically, we investigate the overall average bit error rate (BER), ergodic capacity, and outage probability of the secondary's communication subject to appropriate constraints on the interference power at the primary receivers. We then consider a general scenario where a cluster of relays is available between the secondary source and destination nodes. In this case, making use of the partial relay selection method, we generalize our results for the single-relay scheme and obtain the end-to-end performance of the cooperative spectrum-sharing system with a cluster of L available relays. Finally, we examine our theoretical results through simulations and comparisons, illustrating the overall performance of the proposed spectrum-sharing cooperative system and quantify its advantages for different operating scenarios and conditions. © 2011 IEEE.
SponsorsManuscript received May 3, 2010; revised September 22, 2010 and January 25, 2011; accepted March 3, 2011. Date of publication April 5, 2011; date of current version July 18, 2011. This work was supported by a Discovery Grant from the Natural Sciences and Engineering Research Council (NSERC) of Canada under grant number RGPIN/222907. This paper was presented in part at the IEEE International Communications Conference, Cape Town, South Africa, May 23-27, 2010. The review of this paper was coordinated by Prof. B. Hamdaoui.