Dynamic Spectrum Access Cognitive Radio Network Performance Analysis And Research

At present, large parts of the radio spectrum band are assigned to a particularservice in a way that is often referred to as exclusive spectrum usage. In this case, it willresult in a very low utilization of spectrum resource and seriously hinder thedevelopment of modern wireless communication. In order to solve this contradiction,the concept of Cognitive Radio (CR) has been proposed, which allows low-prioritysecondary users (i.e. CR users) to temporarily utilize the unused licensed channel ofhigh-priority primary users, thereby significantly improving overall spectrum efficiency.Dynamic spectrum access (DSA), as a key application of cognitive radio, has gotuniversal concerns around the world currently. From the point of view of thetransmission delay, we will focus on the performance analysis of CR user system andthe discussion of QoS guarantees in the dynamic spectrum access networks.In chapter1, we will give a brief review of cognitive radio technology background,which include the definition and feature of cognitive radio, the basic architecture andapplications of cognitive radio networks, and etc. The significance and importance ofperformance analysis for the dynamic spectrum access behavior of cognitive radio usersare also presented at the same time.Then, we give an overview of the classification and network access architecture ofthe dynamic spectrum access in cognitive radio network model in chapter2. Thechannel usage spectrum access behavior modeling theory and correspondingperformance analysis framework, which appeared in recent literatures, are alsosummarized in detail.Considering the opportunistic spectrum access (OSA) mode in cognitive radionetworks, the data transmission of primary user and CR user in licensed channel areunifiedly modeled as virtual priority M/G/1queues in chapter3. Based on thepreemptive repeat priority queuing theory, the delay performance of CR user DSAsystem is discussed. The optimal access policy is also proposed under the condition ofsharing multiple channels between CR users. And numerical results validate ouranalysis and design of an optimal access strategy. Considering the network access scenarios similar to chapter3, the behavior of CRuser spectrum access with hopping mode is estabilished as preemptive resume priorityM/G/1network queues. The corresponding data extended delivery time is discussed inchapter4. After the interruption, the comparative delay analysis is carried out under thecase of always-staying and always-changing channel handoff sequences. And theadaptive channel handoff sequence selection options are proposed. The final numericalresults also validate our analysis and design of the adaptive channel switching strategyFinally, the whole thesis is concluded in chapter5. And the future researchdirections for DSA performance analysis are also pointed out.