Research On Scalable Wireless Video Multicast Technology Based On TV White Space

With the development of communication technologies,video services occupy an increasingly high proportion of communication services,and mobile operators need more spectrum to support video services.Due to the fixed spectrum allocation of mobile operators and limited spectrum resources,in order to perform high-quality video transmission,it is necessary to find a transmission method with high transmission efficiency and low bandwidth consumption and sufficient spectrum resources.The development of CR and wireless video multicast technology provides an idea to solve this problem.Through CR,video multicast using TV White Space can not only solve the problem of wireless video multicast,but also effectively improve the spectrum utilization of TV White Space.To this end,this paper proposes a TV White Space scalable video multicast framework based on the purpose of not only improving the transmission efficiency of video multicast,but also ensuring the overall received video quality while allowing each video user to receive its own channel quality.Match the video quality.Under this framework,the main work of this paper includes:(1)In view of the shortage of spectrum resources in the field of wireless video multicast,combined with the advantages of TV White Space,such as a large amount of spectrum available,a wide range of transmission,and strong building penetration ability,it is proposed to be used for wireless video multicast.(2)Aiming at the frequent spectrum switching,high delay and low throughput of the popular opportunistic spectrum access scheme,a geolocation database assisted spectrum access scheme is proposed.The scheme uses the geolocation database to filter out the spectrum to be detected,then uses CR to detect it,and finally completes the access through spectrum selection.The proposed scheme not only avoids the frequent switching of the spectrum but also effectively improves the throughput of the system.(3)In order to improve the transmission efficiency of the system,and avoid the cliff effect and the problem that the enhancement layer encroached on the spectrum resources of the base layer after SVC coding,this paper proposes a cross-layer optimization sub-carrier resource scheduling scheme.The scheme uses proportional fairness as the criterion,subcarrier uniqueness,base layer priority,layer losslessness,etc.as constraints to achieve reasonable allocation of spectrum resources.According to the sensitivity of video multicast delay,a low complexity algorithm is proposed to solve the resource scheduling problem.Finally,the efficiency of the algorithm is discussed through simulation.The simulation results show that the proposed framework effectively avoids excessive spectrum switching,reduces cumulative switching delay,and achieves a system throughput of 45 Mbps.And the cliff effect is avoided,and the video transmission efficiency is increased.Compared with the conventional scheme,the user decoding quality is improved by about 5 dB,and the overall video quality is improved.