| In recent years, the rapid development of wireless communication technology has greatly accelerated the informatization of human society. However, the subsequent increase in spectrum demand can not be satisfied by existing spectrum resources. Meanwhile, under today's static spectrum allocation policy, the utilization rate of spectrum resource is too low. As a result, the progress of wireless communication technology is impeded.As a technology that has been more and more valued by research institutions, cognitive fadio coulcd greatly improve spectrum efficiency without affecting the use of authorized users. This is realized through dynamic spectrum access technology and other key technologies.Current studies on wireless video transmission technology home and abroad mainly focus on3G mobile networks and broadband wireless IP networks. Most of previous researches about cognitive radio concentrated on the coexistence for secondary users and primary users or avoiding confliction and keeping fairness between different secondary users,but few focus on cognitive wireless networks for video transmission technology.What's more,there is not a unified simulation platform to assess the video transmission algorithm of cognitive radio.This study is supported by a key project of the National High-Tech Research and Development Program of China named "Frequency resources sharing based wireless communication systems". The paper firstly focuses on the study of the theory of CR system and the analysis of the performance improvement on frequency utilization of the proposed algorithms. The other contribution of this paper is the design of CR realtime vedio transimission simulation platform, which includes the coding of data exchange interface, the coding of MAC layer of CR bottom layer environment and the coding of graphical user interface (GUI). It should also be clarified that both the design of H.264coder for application layer and the design of transport layer protocol TFRC in cross-layer optimization algorithm are accomplished with Insititde of Acousitc, Chinese Academy of Sciences. Finally, simulation results of the key techniques are demonstrated for performance evaluation. |
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