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Secondary User Cooperation Access Scheme in Opportunistic Cognitive Radio Networks

Opportunistic spectrum access of multiple secondary users is discussed in this paper. The general periodic sensing method leads to a low throughput. An efficient cooperation scheme in distributed Cognitive Radio networks is presented. The secondary user access model uses advantages of instant access opportunities. Since a Secondary User (SU) senses and transmits alternately, two SUs can work in pair to make up a cooperation group and share spectrum bands through data transmission in turn. The best and worst cooperation situations are analyzed. Theoretical results of the throughput are given, supported by simulation results. Throughputs of both members in the cooperation group are improved.