Slow hopping based cooperative sensing MAC protocol for cognitive radio networks

Abstract

A slow hopping based cooperative sensing MAC (SHCS-MAC) protocol is proposed in order to improve aggregate throughput as well as achieve better coexistence with primary users (PUs) and other secondary users (SUs) in cognitive radio (CR) networks where each node has only one half-duplex radio. The proposed SHCS-MAC protocol includes indispensible CR-MAC features such as bootstrapping, multi-channel operation, cooperative sensing, and self-coexistence. Bootstrapping algorithm enables a new node to join a common hopping based network. Slow hopping based multi-channel (MC) operation improves aggregate throughput by enabling concurrent data exchange in different channels on common hopping sequence in which the slot duration can be flexibly selected. Furthermore, cooperative sensing protocol appropriate for the slow hopping based MC-MAC is devised to increase PU detection probability. The improved detection probability enables SUs to promptly evacuate from the channel in which a PU appears. Finally, self-coexistence algorithm is proposed to mitigate the performance degradation due to the interference among neighboring networks. By using extensive simulation and analysis, SHCS-MAC is shown to more efficiently increase network capacity, improve PU detection probability, and achieve self-coexistence with minimal radio cost.