Research Of Spectrum Allocation Algorithm In Cognitive Radio Networks

With the development of wireless communication technology, additional spectrum is requiring to satisfy the demand for various applications and data rates, giving rise to the scarcity of spectrum resources. While, at present, fixed allocation for spectrum is used by the specific communication business, which often turns out to be with low spectrum efficiency and even a waste of spectrum resource. Cognitive radio technology targets at a solution for the spectrum scarcity problem by proposing an opportunistic spectrum usage approach. First, it can automatically sense the spare spectrum, which is switch to the frequency bands that are not being used by their licensed users then. Cognitive radio technology, as a smart spectrum-sharing technology, can alleviate these contradictions effectively.This paper analysed the background of the research projects firstly, explained the definition and function of cognitive radio, and then elaborated the typical application system constructions and the key technology respectively. Two spectrum allocation models in cognitive radio network were studied, one is based on graph coloring theory and the other is based on potential Game Theory. Spectrum allocation model based on graph coloring was presented according to channel throughput weight problem in cognitive OFDM radio network. Proportional Weighted Distributed Fairless Algorithm was proposed with channel weight normalized and power control was considered. The simulation results show that the proportional weighted distributed fairness algorithm has achieved good performance of system throughput and fairness, while with slightly high complexity. A spectrum assignment algorithm based on Potential Game Theory which gave a improvement of the utility function was proposed in a cognitive Ad Hoc network in the paper. The designing process for the algorithm is described in detail and a qualitative analyze for the algorithm is given. The algorithm aims at minimizing the SNR of the whole system, and the main advantage of the algorithm is that it can achieve the Nash Equilibrium fast and shows a better performance on convergence. The cognitive radio spectrum allocation technique based on the game theory has been regarded as a new path to the dynamic spectrum allocation study. It laid a more solid theoretic foundation for the development of cognitive radio and injected more pushing power to its development.