Research On Video Distribution Strategy In Fiber-Wireless Access Network

Fiber-Wireless(Fi Wi)Access Network has the advantages of high bandwidth,low loss,and long-distance transmission of optical networks,as well as high flexibility,high mobility,and low deployment costs of wireless networks.It has become one of the key technologies for broadband access.At the same time,with the widespread use of smart devices,video services will gradually become the main business in the network.Since video have delay-sensibility,in order to provide better video services to users,it is very important to establish appropriate video distribution strategy and improve the quality of experience(Qo E)of users in combination with the characteristics of Fi Wi network and the actual needs of users.Therefore,this thesis focuses on video distribution strategies in Fiber-Wireless access networks.The main research contents are as follows:First,this thesis introduces the research background,network architecture,technical characteristics and research hotspots analysis of Fi Wi.Then the current widely used streaming media technology is introduced.The thesis focuses on the video distribution strategy in Fi Wi,including video end-to-end transmission optimization,user experience quality overview and video caching strategy.Second,this thesis proposes an quality of experience-aware video multicast mechanism is proposed to reduce the resource waste caused by traditional multicast methods in Fiber-Wireless access networks.Specically,a Qo E evaluation model is built with consideration of video interruption rate,video quality,and smoothness.After that,the coverage and transmission capability of the optical network unit are analyzed,a bipartite graph is constructed based on which the multicast tree is obtained by solving the minimum dominating set problem.Finally,a video quality adjustment algorithm based on the user buffer state is proposed to realize adaptive multicast transmission of scalable video streams.The results show that the mechanism proposed in this thesis can effectively enhance the quality of user experience by reducing the rate of video interruption.Thereafter,in order to solve the problem of user delay caused by the limited link resources in video on demand,this thesis proposes a video service delay optimization method based on layered cache.Firstly,a method of layered caching is proposed in the optical and wireless domains to provide cache for popular video content.Further,the delay minimization problem is constructed according to the different positions where the user obtains the video segments,and the particle swarm optimization is used to allocate the best transmission rate for each quality layer to achieve the purpose of minimizing the delay.The results show that the mechanism proposed by this thesis can effectively improve the cache hit rate and reduce the video transmission delay.In the end,the research works in this thesis are summarized,and the future research directions are prospected.