Multimedia Transmission Optimization In Wireless Network Under Mobile Scenario

With the rapid development of wireless network technology and the popularity of portable mobile devices,the number of people receiving multimedia services through mobile devices has increased explosively.The mobile multicast services,such as video chat,short video,and mobile game,have been greatly developed and are poised to pervade people's daily life.Although high-quality mobile multimedia services have enriched people's life,the large amount of data puts a high burden on wireless networks.According to the current development of the wireless network,the enhancement of wireless network capacity cannot catch up with the dramatically increasing demands,and the problem of this mismatching will become more and more serious.Therefore,it is important to have a research on how to provide high-quality multimedia services for mobile users under limited network resources.In addition,some future network architectures proposed in recent years,such as Software Defined Networking(SDN)and MobilityFirst(MF),provide new ideas for wireless resource allocation and mobility support.The promotion of multimedia technologies such as video multicasting and Scalable Video Coding(SVC)provides technical support for dealing with the problem of network data redundancy and heterogeneity of mobile devices.This dissertation studies the multimedia transmission optimization under different mobile scenarios.This dissertation aims to improve the quality of experience of users by combining the multi-media technologies with future network architectures and using Lyapunov theory as the technical means.The main contributions are summarized as follows:1.This dissertation proposes a scalable video transmission strategy in dense small-cell network.The dense small-cell network is emerging as a promising wireless network due to its characteristics of high spectrum efficiency,large bandwidth and low power consumption.However,the dense small-cell network lacks the coordination between the base stations,which causes the wireless resource cannot be utilized effectively.Therefore,the dense small-cell network is incapable of taking the advantages of itself.This dissertation designs a complete scalable video transmission system,which applies the SDN technology to the dense small-cell network to achieve the cooperation between the base stations.In addition,this dissertation makes joint decision of video layer selection,wireless resource allocation and transmission scheduling to maximize the time-averaged quality of experience of users.By employing the Lyapunov optimization method,the original problem is further decomposed into three independent subproblems.The solution derived for our video delivery system is an online measurement-driven approach operating without any prior statistical knowledge.This dissertation evaluates the performance of the proposed approach.The results verify that the proposed method is capable of providing a prompt response to dynamic environmental fluctuations and achieves better performance than other algorithms.2.Due to the popularity of multimedia services such as live video and video conference,the network is full of duplicate data.Multicast is a one-to-many transmission mechanism,which can significantly reduce redundant data in the network.This dissertation proposes an SVC multicast transmission system in the Long Term Evolution(LTE)by combining SVC technology and multicast trans-mission,so that the users suffering different cannel qualities are able to receive differential services.Besides,the proposed system is able to reduce the redundant data in the network at the same time.This dissertation aims to improve the quality of users' experience under the proposed system by assigning the appropriate kind of Modulation and Coding Scheme(MCS)as well as RB resource for each video layer.In order to solve the optimization problem,this dissertation proposes a two-stage strategy to assign MCS and allocate RB for each video layers.In the first stage,each multicast groups are preallocated RB resource by the proportional fair method.Then,in the second stage,the proposed strategy uses Lyapunov optimization method to assign MCS and to allocate RB resource for each video layers in a single multicast group.The simulation results verify the effectiveness of the proposed algorithm.3.This dissertation proposes a multicast transmission system in MF network,which is a novel future network architecture.The MF network is a mobile-centric future Internet architecture,which supports seamless host and network mobility.It provides a new choice for mobile multimedia services.This dissertation designs an efficient multicast mechanism based on MF architecture and presents the deployment of the multicast system in current network at scale.Based on the multicast system,this dissertation proposes a low-cost dynamic multicast routing mechanism by using a hierarchical multicast packet header with additional destinations.The proposed routing mechanism provides solutions for both the multicast source and the multicast group members moving in intraor inter-domain.Finally,this dissertation presents a multicast prototype system and evaluates the performance of the proposed multicast routing mechanism.The results prove that the proposed algorithm can effectively improve the quality of experience of users in mobile scenarios.