A dual-threshold-based optimization of spectrum sensing time

Recent studies have been conducted to indicate the ineffective usage of licensed spectrum due to the fixed spectrum allocation. In order to solve this problem, the cognitive radio is introduced to perform opportunistic usage of spectrum of primary users by a secondary user, without interfering with the quality of primary users. Therefore a secondary user should be capable of spectrum sensing. In this paper, we study the problem of designing the optimal spectrum sensing time, under considering spectrum handoff and dynamics of the state of primary users and dynamics of the priority-ranking of channels, so as to maximize the expected net reward in throughput of a multiple-channel cognitive radio network in which there is at least a idle channel at one time, meanwhile, the energy cost of spectrum sensing and data transmission is taken into account. We analyze the problem using the framework of partially observable Markov decision processes (POMDP).