Dynamic spectrum access strategy for cognitive wireless networks based on two channel sensing

A dynamic spectrum access strategy based on two channel sensing is proposed for the spectrum access model in multi-channel multi-user scenarios. The strategy reduces the contention of cognitive users to the channel by sensing the dynamic allocation of spectrum channels. The number of the perceptual access channels is adaptively allocated according to the number of access users, and the collision interference to the authorized channel is reduced. Then based on the above model, a hybrid dynamic spectrum access strategy is proposed, and the Overlay/Underlay hybrid access mode is adopted instead of the original single Overlay access mode. By setting the probability threshold to reduce the perception of the channel with lower credibility, the cognitive user adopts the Underlay access mode shared transmission at a lower transmission rate. The simulation results show that the proposed two dynamic spectrum access strategies can effectively reduce the collision probability and improve the network service quality.