Optimal Channel Sensing in Wireless Communication Networks with Cognitive Radio

In this paper, designing channel sensing policies for cognitive radio networks is discussed. A discrete-time semi- Markov channel model is first introduced, which facilitates the analysis on more general channel occupancy behaviors and possible asynchronism among primary and secondary users. Based on the characteristics of the channels at the stationary state, multiple channel sensing policies have been proposed for different network scenarios with homogeneous channels, heterogeneous channels, and sequential channel sensing. Both analytical and simulation results are given to demonstrate the effectiveness of the proposed channel sensing policies.