Research On The Technology Of DASH Video Multicast Based On LTE Network

In wireless communication services,video service occupies a large proportion in the number of users and data traffic.However,with the development of wireless network technology,the requirement of video service is constantly improving,which brings some new challenges for wireless networks such as lack of spectrum and low utilization of resources.Dynamic Adaptive Streaming over HTTP(DASH)and wireless multicast technology provide a feasible solution for the above problems.DASH users can choose the appropriate bitrate according to their own channel conditions,which breaks the limitation of fixed-bitrate transmission and improves the resource utilization.In wireless multicast,spectrum sharing strategy is adopted to improve the spectral efficiency,which makes the users in the same multicast group receive a copy of bandwidth.In addition,the third generation partnership project(3GPP)long term evolution Term Evolution(LTE)system provides multimedia broadcast multicast service(MBMS)to support the realization of video multicast.Combining DASH with multicast,the paper proposes a new framework of DASH multicast system and designs a set of user grouping and resource scheduling scheme,which solves the problem of video transmission under current network by utilizing the advantages of DASH and multicast.In this paper,we first describe the basic concepts and principles about DASH multicast system based on LTE network and introduce the performance evaluation index of DASH video.Then,the architecture of the DASH multicast system is elaborated in detail.This architecture is divided into three parts:DASH source server,multicast server and MBSFN area.Among them,multicast server is responsible for the function of user division which has a great impact on system performance.The determination of group's number and the selection of grouping methods are two difficult points in design.In view of the shortcomings of traditional grouping scheme,this paper proposes a DASH multicast grouping algorithm based on K-means clustering and devises a method to determine the K value automatically.Compared with the traditional scheme,the proposed scheme obtains a favourable effect under the premise of low complexity.In addition,resource scheduling is a hot research point in network resource management.The performance of resource scheduling algorithm will affect the quality of network and user experience.However,in LTE network,traditional and Quality of Experience(QoE)oriented scheduling algorithms do not consider the characteristics of multicast.If they are used directly in DASH multicast system,they may not achieve good performance.Therefore,this paper proposes a DASH multicast scheduling algorithm based on multicast information and user feedback.In the process of design,we construct a utility function for DASH users and calculate the sum of untility as the optimization objective.Then,the resource allocation strategy is obtained by soloving this problem.The experimental results show that the proposed scheduling algorithm reconciles the throughput and fairness and outperforms other scheduling algorithms under the index of the average DASH version and the QoE-Mean Opinion Score(MOS),which indicates our schmem is more suitable for DASH multicast system.