Study On Spectrum Allocation Technology In Cognitive Radio Network

With the rapid development of people’s need for wireless communication service,the available spectrum resources become increasingly nervous. In order to enhance theutilization rate of spectrum resources, and solve the problem that wireless spectrum cannot be effectively used, a new spectrum sharing technology of Cognitive radio (CR)technology is born at the right moment. CR is a kind of intelligent wirelesscommunication system where second users (SU) can sense the environment and find outthe “spectrum hole” which is not being used for the moment, and intelligently accessand dynamically use the free frequency band without affecting the commoncommunication of Primary User (PU), and then the utilization rate of spectrumresources can be enhanced and alleviate the problem of nervous spectrum resources.Spectrum allocation, as a key technology of cognitive radio, can make effectivespectrum allocation strategy in terms of the wireless environment around, and make theusers effectively use free spectrum, and improve the whole cognitive system.This paper mainly investigates the spectrum allocation technology, which is one ofthe key technologies of CR. This paper analysis the development, research status fromdomestic and abroad and several kinds of standard technologies of CR, and investigatessome commonly used spectrum allocation models of spectrum allocation technology.Considering that different allocation model has different allocation algorithm, the paperalso briefly analyzes the properties of corresponding algorithms.The main aim of CR spectrum allocation is to realize the system benefitmaximization, combined with the optimal characteristics of genetic algorithm, aspectrum allocation scheme based on an improved genetic algorithm is proposed in thispaper. Comparisons and simulation results show that the improved genetic algorithm issuperior to the traditional and adaptive genetic algorithm obviously in optimization ofsystem benefit maximization in spectrum allocation, and it can effectively improve theability of spectrum allocation in CR.On the basis of system benefit maximization, considering that different users havedifferent quality of service (QoS) requirement, this paper also proposes a spectrumallocation algorithm based on QoS grading of SU. The main idea of the spectrumallocation algorithm is to construct a fuzzy comprehensive decision model based onQoS grading, and then employ the spectrum allocation combined with the CMSB algorithm of graph theory model. Experimental simulations demonstrate that theproposed spectrum allocation strategy based on QoS grading not only meets the QoSdemands of SU, but also ensure the higher average throughput and fairness. Theproposed spectrum allocation strategy realizes an effective usage of free spectrum,improves the utilization rate of spectrum and the performance of cognitive radio system.