Rsesearch On Video Transmission Strategy In Fiber-Wireless Access Network

The Fiber-Wireless Access Network(FiWi)not only has the advantages of large transmission capacity and wide coverage of the optical access network,but also includes the features of wireless access network such as low deployment cost and supporting for mobility.Which is one of the key technologies for next generation of broadband access technology.At the same time,due to the emergence of smart terminals,such as mobile phones,laptops,and tablet computers,video,as one of the most represente in multimedia services,has gradually become the main business of the network.And the sensitivity of delay,jitter and mobile viewing have become major factors affecting Quality of Experience(QoE).FiWi network can provide good physical transmission conditions for video services.However,due to the special structural characteristics,it cannot directly use the traditional network video transmission strategy.Therefore,how to establish a suitable video transmission strategy according to structural characteristics of the network and the user's request information is an important problem in current FiWi network.This thesis details the background and key technologies of FiWi network firstly.And the QoE's assessment model is introduced,including the influence factors of QoE.Then by comparing two mainstream QoE assessment methods: subjective test method and objective QoE monitoring,the differences and advantages of them are analyzed.Secondly,an QoE-aware video distribution mechanism is proposed.In this mechanism,the link state information and scalable video coding structure are considered to establish a QoE evaluate model,and the particle swarm optimization algorithm is used to select optimal video transmission rate.Furthermore,transmission path for the services is selected by analyzing transmission capacity and matching degree of the node to ensure the reliable transmission of services.The results show that the proposed mechanism can not only enhance the quality of the user experience but also improve the utilization rate of network resources and reduce network congestion.Thirdly,a video quality assurance mechanism is proposed.According to the current channel condition and video content,an underflow probability analysis model is derived based on the principle of large deviation,and this model is used to switch the video layer.Then,based on the principle of perturbation,the quality fluctuation in switching process is reduced,and the viewer's experience quality can be improved.The results show that the proposed mechanism can reduce interruption in video playback and guarantee video quality.At last,the main work contents and innovations of this thesis are summarized,and the plan in future work is proposed.