Based On The Spectrum Of Cognitive Radio Network Research And Implementation Of Management Mechanism

With the rapid increment of wireless communication applications, people haveclaimed higher performance of wireless network, which leads to more demands ofbandwidth, wireless spectrum has became a scarce resource. However, the traditionalfixed spectrum allocation policy limited utilization of spectrum resource. According tothe research of Federal Communications Commission (FCC), a large portion of theassigned spectrum is used sporadically, which cause a huge waste of spectrum resource.Cognitive radio technology is expected to resolve this problem. It enables wirelessdevices use the licensed spectrum dynamically as secondary users without causingserious interference to the primary users. Compared with traditional network technology,cognitive radio has special character of uncertain work spectrum, quick change ofspectrum environment, requirement of instant avoidance of primary user and so on, thusmake a lots of challenges to the design and implement of the protocol.Our work based on the first cognitive radio experimental system in China: thedynamic spectrum bandwidth wireless communication system (the DYS system). Wepropose a protocol framework for the hybrid network architecture; design the spectrummanagement mechanism of the system and inplement the protocol in a real system. Thecorretness of our mechanism has been verified by emulation. We also analyse somedefects of system, such as low spectrum utilization, centralized spectrum decision, andson on.This paper proposed New-DYS algorithm to enhance the performance of DYSsystem. The New-DYS algorithm has following features compared to existing design ofDYS system:1) The New-DYS algorithm allows system to use more channel and bringhigher spectrum utilization.2) The New-DYS algorithm has no need of a centraldecision node, which make network be more elastic while handling complex spectrumenvironment. Simulation result shows that New-DYS algorithm provides betterperformance in terms of throughput and packet drop ratio.