Spectrum allocation based on the time-varying characteristic of the spectrum holes in cognitive radio

Spectrum hole has the time-varying characteristic in cognitive radio. The activity of the primary user is one of the concerned factors in time-varying characteristic. Another factor is that the second users, who monitor the activity of the primary user s in different geographic locations, could get various arrival rates of primary users on the same spectrum hole. The third factor is the probability of different second users being interrupted by returning primary users on the same spectrum hole. Firstly, the quantitative analyses for time-varying characteristic are studied. Secondly, the spectrum allocation algorithm based on time-varying characteristic is proposed to optimize the matching between second users and spectrum holes, which introduces the repeated greedy algorithm. Thirdly, the performance is evaluated by simulation.