【作者】 林新鉴；

【导师】 傅丰林；

【作者基本信息】 西安电子科技大学 ， 通信与信息系统， 2010， 硕士

【摘要】 传统无线通信系统对频谱的利用是基于固定频谱分配策略,无线通信系统只能严格按照频谱的划分,使用授权的频段,这导致了严重的频谱资源浪费。作为认知无线电技术的一项重要应用,动态频谱接入能根据相应的频谱使用规则,利用通信过程中出现的频谱机会适时地接入频谱,在提高频谱利用率方面有着重要的意义。本文的研究重点是基于部分可观测马尔科夫决策过程(POMDP)的机会频谱接入算法。算法的改进主要针对多认知用户贪心算法的自私性不足,为此引入了分布式协调团体和协作接入的概念,研究了基于POMDP的分布式协作接入算法,并给出具体的算法流程和MAC层设计细节。仿真结果表明,在算法复杂度无明显增加的前提下,分布式协作接入算法较之贪心接入算法,系统吞吐量和频谱利用率有明显的提升。更多还原

【Abstract】 Today’s wireless communication systems are characterized by a fixed spectrum assignment policy. The utilization of spectrum is strictly limited by the division and authorization, resulting in a serious waste of spectrum resources. As an important application of cognitive radio, dynamic spectrum access (DSA) can improve the spectrum efficiency by timely accessing spectrum holes according to temporal and spatial traffic statistics during the communications.This paper mainly researches opportunistic spectrum access (OSA) algorithm based on Partially Observable Markov Decision Process (POMDP). Aiming at the selfish of the greedy approach in OSA networks with multiple secondary users, the improved algorithm, named distributed cooperative spectrum access algorithm based on POMDP, is given which adopts the concepts of distributed coordination and cooperative spectrum access. Simulation shows that the improved algorithm increases the throughput of the network and the efficiency of spectrum utilization, while there is no significant increase in complexity comparing to the greedy algorithm.更多还原