A New Mechanism of Dynamic Spectrum Allocation in the Cognitive Network

Cognitive radio is thought to be a flexible way to improve the spectrum efficiency. The major challenge is that the communications in the cognitive radio network would be affected by the behaviors of licensed incumbents. The cognitive system must vacate the channel within moving time whenever the licensed incumbents re-occupy that channel, in order to reduce the interference to the licensed system. Besides, in the licensed system, the channels are used by licensed incumbents independently, therefore, the licensed channels have different occupancy ratio. In this study, we propose an improved mechanism considering the channels characteristics in spectrum allocation. The new method can make use of the spectrum characteristics to maximum the spectrum availability and reduce the probability of drop rate in the cognitive system. Besides, our proposed scheme can guarantee the fairness among multi-cells. Through simulation results, it is shown that the proposed scheme can enhance performance of the cognitive network.