Clustering In Hierarchical Spectrum Sharing Network And Routing Algorithm Design

Cognitive radio (CR) technique is considered as one of the solutions of current spectrum resource scarcity. Its core idea is to exploit the licensed but underutilized spectrum, in order to improve the spectrum efficiency. Cognitive radio technology, which is considered as a confined concept in coined stage, has become one of ten hotspot communication technologies in the future, involving research on network architecture and key technologies from PHY layer to network layer. This thesis mainly investigates the clustering and routing algorithms in the cognitive radio based Hierarchical Spectrum Shared Network (HSSN).According to the different research direction, it can be divided into four parts:In the first part,background and significance of researching on cognitive radio is first investigated and the research status and problems in cognitive radio network architecture are also reviewed and summarized. Meanwhile, based on the impact of cognitive radio's characteristic on the network architecture and its key technologies, the main research motivation and startpoint of this thesis is also indicated.Since cognitive radio based HSSN is the research foundation of this thesis, this network is introduced in the second part. It involves the idea of hierarchical spectrum sharing, the method and rule of available spectrum identification and classification implementing such network, and the communication mechanism how to use different spectrum categorizes for different service requirement. In addition, the system model of high priority user for the HSSN is constructed and the performance of this network is also evaluated from the angle of examining overhead. The HSSN can realize optimization for network architecture and be satisfied with requirement of dynamic spectrum allocation, while it can significantly provide a considerable extension to the available spectrum.Caused by the spectrum heterogeneity in cognitive radio network, it is usually difficult to obtain a common control channel. To solve this problem, the third part of this thesis proposes a clustering algorithm based on multiple channel access in the HSSN. Cognitive radio users in the HSSN can share a Local common control channel (LCCC) instead of a global control channel in each cluster. Simulation results show that the clustering architecture conducted by the proposed clustering algorithm is stable and efficient in solving the problem in obtaining a common control channel.The last part of this thesis proposes a decoupled route selection and spectrum management protocol, which adapts itself well to the multi-hop communication mechanism in the HSSN. This algorithm analyzes the affects from spectrum stability, considers anti-intermittence routing and gives out specific description of computation of route metrics and routing discovery and so on. Besides, a large amount of computerized simulations are shown in this part to evaluate the performance of this algorithm.