Research On Dynamic Spectrum Allocation Algorithm In Cognitive Radio

With the recent boom in wireless technologies, the spectrum resource have become more and more crowded. There is few spectrum left for new wireless technology. Nevertheless, it is reported that the average using ration of licensed spectrum allocated by traditional way was just between 15%～85%, and the using ratio was low in many hours.Cognitive radio technology is created to address these problems, and the dynamic spectrum allocation is the key technologies of a cognitive radio(CR) system.The research has important theoretical and practical value.For the dynamic features of cognitive radio channel state, model of spectrum occupancy has been studied in this paper. The use of Markov models for the spectrum occupancy and channel state prediction is depended on the probability of statistic estimate. Based on the results of the estimation, predict the real-time spectrum occupancy and achieve channel capacity estimation, at the same time, give a new formula for channel capacity estimation. The simulation results show that the methods of channel state prediction and channel capacity estimation are very high accuracy. That provides a good reference for QoS-based dynamic frequency selection.The existing spectrum allocation method focuses on the conflict-free allocation, as well as to maximize spectrum utilization, etc. There is no full account of the statistical information of dynamic spectrum, users of different business needs of different bandwidth and real-time - non-real-time needs. In this dissertation, the dynamic spectrum allocation for CR based on statistical information and multi-queue has been studied. At the same time, compared the exclusive allocation methods with spectrum pool sharing methods, the simulation results show that in the case of centralized control, spectrum pool sharing to ensure better fairness and spectrum switching, to provide higher throughput of the system.