FCM: Frequency domain Cooperative sensing and Multi-channel contention for CRAHNs

Radio spectrum resource is shown to be significantly underutilized with fixed spectrum assignment policy. As a promising solution, cognitive radio allows unlicensed users to opportunistically access the spectrum not used by the licensed users. Cooperative sensing is further exploited to improve the sensing performance of unlicensed users by leveraging spatial diversity. However, cooperation gain can be compromised dramatically with cooperation overhead. Furthermore, when sensing decisions are made, contention on spectrum access also becomes an overhead, especially in the distributed networks. Motivated by this, we propose a novel MAC design, termed Frequency domain Cooperative sensing and Multi-channel contention (FCM). FCM moves cooperative sensing and multi-channel contention from time domain into frequency domain. Thus, the control overhead caused by cooperation and contention can be significantly reduced, without reducing the sensing and access performance. Extensive simulation results show that FCM can effectively reduce the control overhead, and improve the average throughput by 220% over Traditional Cooperative MAC for CRAHNs.