【作者】 张华晶；

【导师】 陶成；

【作者基本信息】 北京交通大学 ， 通信与信息系统， 2011， 硕士

【摘要】 随着无线通信技术的高速发展以及无线应用的不断拓展,频谱资源中“贫富差距”的现象越来越明显,即一部分频谱资源时常拥挤不堪,而另一部分频谱资源却时常处于空闲状态。为择机利用空闲频谱资源,认知无线电应运而生。因为认知无线电网络中的频谱资源是根据时间、地理位置及授权用户的活动情况的不同而变化的,所以认知无线电网络中的特有频谱分配算法已成为认知无线电系统中的研究热点。本文首先介绍了目前频谱资源的利用现状,阐述了认知无线电出现的原因以及一些基本概念,分析总结了认知无线电中频谱分配算法的研究现状；然后介绍了认知无线电中频谱分配策略的分类和设计频谱分配算法时应遵循的原则,总结了认知无线电频谱分配算法常用的几种模型；接下来介绍了图着色模型的一些基本概念并对建模过程做了更贴合实际的解释,并提出图着色频谱分配的扩展模型,然后分析总结了现有基于图着色模型的频谱分配算法并分析其优缺点；最后,根据对现有算法的优缺点分析及结合认知无线电系统的特点,改进了列表着色贪婪算法及公平算法,重点提出了一种基于用户需求和频谱聚合的频谱分配算法。经仿真验证,使用该算法可以获得满意的性能,同时,当网络中可用总频谱资源远大于用户总需求时,该算法性能将逐渐接近穷举法性能。更多还原

【Abstract】 With the development and the wide application of the wireless communication technologies, the phenomena is more and more apparent that a part of spectrum are overcrowded while others are idle on many occasions. By opportunistic accessing the idle spectrum, cognitive radio improves the utilization of the spectrum. Special spectrum allocation algorithms are essential to adapt the dynamic characteristics of the spectrum in cognitive radio.This thesis firstly introduces the background, basic concept and the development of cognitive radio. And then, the classification, design principle and the models of spectrum allocation are summarized. The spectrum allocation algorithms based on Graph-Coloring theory are fully studied, and their advantages and disadvantages are summarized. Based on that, this thesis presents the improved greedy algorithm and the improved fair algorithm. At last, this thesis introduces a new spectrum allocation algorithm taking user requirements and discontinuous spectrum allocation into consideration based on the Graph-Coloring theory. Simulation results show that the satisfying performance can be obtained by using the proposed algorithm. By comparing with the exhaustive search method we can see that the performance of the proposed algorithms id equal to the performance of the exhaustive search method when there is much more available resource than the users demands.更多还原