Research And Simulation Of QoS-Based Video Transmission Strategies In Cognitive Radio Networks

Nowadays, wireless communication technologys are developing rapidly, and lead to the sharp rise of requirements of wireless communication services. But the existing spectrum allocation scheme of wireless spectrum resource has many disadvantages, such as statical wireless spectrum allocation scheme, low utilization radio and so on. It can't meet the demand of large amount of spectrum requirements. In order to slove these problems, researchers invented a new technology, cognitive radio technology, which used dynamic spectrum allocation scheme. In cognitive radio network, the requirements of video transmission are important parts of wireless communication business, so how to improve the quality of video transmission service in cognitive radio network is the focus of this paper. In this paper, we used parameters of the quality of service(QoS) to measure the video transmission services, which used the new video transmission strategy.In cognitive radio network, primary users(PUs) owned the spectrum, but when secondary users(SUs) meet the conditions, they also could access the spectrum in overlay or underlay. In this paper, we research the video transmission strategy in the two ways. Firstly, in the overlay access mode, we selected the centralized structure cognitive radio network, and use Peak Signal to Noise Ratio(PSNR) model to measure the sum of secondary users' QoS. With packet loss and data rate's impact on QoS of secondary users considered, we come up with the cross-layer optimization problem and solved it with greedy through. Secondly in the underlay access mode, we selected the general interference temperature model to manage the users' interference, and changes the SUs' transmit power to ensure the sum of SUs' interference below the threshold. Then we analysed the relations of transmit power, data rate and QoS, and come up with the optimal question. According to the attribute of the optimal question, we resolved it into many independent sub-questions and solved it with greedy through.Lastly, we proved the video transmission strategies in the two ways can improve the average SUs' QoS.