认知异构无线网络中频谱切换建模与分析

在具有频谱认知功能的异构无线网络中，针对传统频谱切换算法未考虑次用户业务的多样性，且空闲信道不足造成次用户服务时延大的问题，提出基于次用户分级的频谱切换策略。与以往单一的认知无线电网络不同，该策略融合利用免授权频谱的开放式无线网络和机会式利用授权频谱的认知无线电网络，提出了认知异构无线网络场景。根据次用户的业务类型对其进行优先级划分，并在此基础上设计数据分割因子优化策略。进一步采用混合式抢占优先权(preemptive resume priority /non-preemptive resume priority，PRP/NPRP) M/G/1排队模型，分别对主用户网络和开放式无线网络中的频谱切换过程进行建模，提出一个最小化时延的动态自适应频谱切换策略。实验仿真了不同参数对次用户时延的影响，结果表明，该策略较传统的频谱切换策略明显提升了次用户的时延性能。

Analysis for spectrum handoff in cognitive heterogeneous radio network

In the heterogeneous wireless network with spectrum cognitive function, a spectrum handoff strategy based on secondary user classification is proposed, aiming at the problem that the traditional spectrum handoff algorithm does not consider the diversity of secondary user services and the lack of idle channels causes the large services delay of secondary user. Different from the previous cognitive radio networks, we propose a cognitive heterogeneous wireless network scenario by combining the open wireless networks that utilize unlicensed spectrum and cognitive radio networks that utilize licensed spectrum opportunistically. Secondly, the priority of secondary users is divided according to its delay requirements. And on this basis, the data segmentation factor optimization strategy is designed. Furthermore, the preemptive and non-preemptive M/G/1 queuing models are used to model the spectrum handoff process in primary user networks and open wireless network respectively, and a dynamic adaptive spectrum handoff strategy with minimum delay is proposed. The effects of different parameters on the delay of secondary users are simulated. The results show that the proposed scheme improves the delay performance of secondary users significantly compared with the traditional spectrum handoff scheme