| In the modern times, wireless networks had gained widely application with the popularity of wireless communications businesses. On the other hand, the confliction between the demand of the broadband services and the limited wireless spectrum resources become increasingly prominent. So, in order to ease this contradiction, Cognitive Radio appeared on the scene as "the Next Big Things"Cognitive radio technology could search and use licensed spectrum automatically, through sensing spectrum environment of frequency domain, time domain and space domain, to improve the utilization efficiency of radio spectrum in wireless network. On the basis of previous study results, the paper focuses on dynamic topology management and spectrum allocation in the cognitive wireless Mesh network model as follow:(1)To solve the dynamic topology management problem, we have carefully analyzed the process of cluster formation, maintenance and restructuring. Then, an improved algorithm is provided for clustering, which has designed a mechanism based on diversity of spectrum quality and motion information of cognitive nodes. The simulation results show that we proposed can get a good performance on the cost of cluster management and spectrum utilization compared with the Local Minimal Dominating Set algorithm and comparability based adaptive clustering algorithm.(2)The key areas of the second work include:analyzes the mainstream Graph theory algorithms (such as List Coloring, Color Sensitive Graph Coloring, and Parallel Algorithm) and proposes a proportional fairness allocation algorithm based on node’s demand. The key idea of the algorithm was to design a proportional coefficient of actual flow to demand flow. Then cognitive users with the prior proportion could access their optimal channels and exchange message during every allocation round. The results of simulation show that the proposed algorithm improves the throughput and fairness of cognitive wireless Mesh network. |
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