Multipath Transmission Of Video Streaming For Edge Computing

With the development of mobile Internet,more and more people use mobile terminals to obtain video-related services.Video transmission requires high bandwidth and low delay.How to efficiently transmit video stream in the network and provide high quality video service for users is an urgent problem to be solved.Multipath transmission is data transmission on multiple disjoint paths,which can aggregate network bandwidth and improve transmission performance.Path allocation and end-to-end transmission control are important factors affecting the quality of multipath transmission.The software defined network(SDN)separates the control plane from the data plane,which can efficiently realize the path allocation and end-to-end transmission control of video stream.Scalable Video Coding encoding video as a base layer and a number of enhancement layers makes it possible to combine with SDN technology to realize multipath transmission of video stream in the application layer.At the same time,due to the mobility of the terminal,the terminal handover is also a problem to be considered.Aiming at the mobile edge network environment,this thesis studies and designs the wireless access point handover scheme and the multi-path transmission scheme of SVC video streaming based on SDN related technology.The main contributions of the thesis are summerized as follows:(1)In the mobile edge network,a QoS-based wireless access point handover scheme is proposed.In the simulation experiment of linear moving model,the proposed scheme reduces the average delay by 4.35% and improves the average throughput by 2.1% compared with the passive switching scheme.In the simulation experiments based on the Gauss-Markov movement model,compared with the passive switching scheme and the RSS-based scheme,the proposed scheme reduces the total times of AP handover by 18.42% and 58.06%,respectively.(2)As the media presentation description file of SVC video only contains the average bit rate of each layer,the hierarchical correlation of SVC video layers is found through analysis,and the bit rate prediction scheme is proposed.Furthermore,the multi-path discovery algorithm and the multipath transmission decision algorithm are proposed to form the multi-path transmission scheme of SVC video stream.(3)A multi-path video stream transmission system was designed and implemented according to the above method,and a comparative experiment was conducted on the simulation platform Mininet-wifi,and the video transmission quality was evaluated by the PSNR,structural similarity and video lag times.In the video transmission experiment of terminal static,for video Big Buck Bunny,compared with the basic transmission scheme,the multi-path transmission method in this paper improves by 3.98 and 4.79 in PSNR index,and 0.0351 and 0.0431 in SSIM index,respectively.In the video transmission experiment of terminal mobile,for video Big Buck Bunny,the AP handover method in this paper reduces the lag times by 38.46% and 55.56% respectively compared with the traditional AP handover method.