The Reaserch Of Spectrum Allocation Algorithm In Cognitive Radio Network

The scarceness of wireless spectrum hampers the sustainable development of the wireless communication and services, cognitive radio (CR) provides a feasible solution for contradiction between the spectrum resources scarcity and increasing radio access demands, via using the licensed spectrum by the "secondary use" mode. This new wireless technology can sense the wireless environment, search for available spectrum resources and allocate spectrum dynamically, so that the efficiency of spectrum is improved and the capacity of wireless communication system is increased. This new technology arises as a hot research topic in wireless communication. Spectrum allocation, one important part of the cognitive radio technology, which uses network resources effectively and increases the system capacity, plays a vital role in cognitive radio system performance.This paper mainly analyzed the background of research and focused on spectrum allocation model and algorithm in cognitive radio system. Firstly, this paper briefly introduced the basic concepts and key technologies of cognitive radio technology and analyzed two types of spectrum allocation technology in cognitive radio network. In the next third and fourth chapters, spectrum allocation algorithm and the clustering mechanism of spectrum users which need to be allocated in cognitive radio network were studied.In the third chapter, the theoretical model based on graph coloring were analyzed and studied at first and several current distributed classical algorithms were summarized. Focused on three basic algorithms, three modified spectrum allocation algorithms were proposed by adding the weight value of channels. Finally, the performance of throughput, fairness and complexity of these algorithms were analyzed, and their practical applicability was summarized.In the fourth chapter, the clustering mechanism in distributed cognitive radio network was studied. Based on the deep study of the current characteristics of the cognitive radio network and users' network structure, aiming at resource-constrained problem to the difference of users' available channel, the concept of available channel similarity was introduced and the comparability based adaptive clustering algorithm(CBAC) was proposed. Simulation results show that the algorithm improves the average numbers of the link available channel, reduces the renew times of cluster-head users. Compared with traditional clustering algorithm, this algorithm improves the stability of the system, saves costs and increases the efficiency of spectrum use.