Abstract:Based on the anterior knowledge model, a Dynamic Spectrum Access(DSA) algorithm was proposed according to the Channel Remaining Idle Time(CRIT) estimation. Each Secondary User(SU) maintained an estimation vector of the CRIT and upgraded it periodically. At the beginning of each time slot, SU chose a channel with the largest CRIT estimation to access. The adaptability of the DSA algorithm was analyzed and the optimal transmission time for the SU was obtained. Simulation results show that the new algorithm has 5%-10% higher channel utilization efficiency than other ones under certain channel parameters while making the lowest interference to Primary Users(PU).