Optimal Cooperative Sensing Scheme Under Time-Varying Channel for Cognitive Radio Networks

For the cognitive radio (CR) network, in order to obtain more spectrum access opportunities, each CR user has to monitor all the licensed bands and opportunistically transmit in multiple spectrum bands whenever no primary signal is detected. However, they are constrained by hardware and energy cost. In this paper, a novel multi-channel cooperative sensing scheme is proposed to reduce the overhead of wide-band sensing by one CR user. In this scheme, some CR users are selected to sense the distinct channels at the same time. When the available channels have been found, the CR user who has data to transmit will choose the best channel to access. The variation of channel capacity is characterized by the finite-state Markov channel (FSMC) model. Performance analysis and simulation of the proposed multi-channel sensing scheme are presented. The results show that our scheme improves the CR network throughput and reduces the time overhead of wide-band sensing.