Key Technologies Of 5G Networks-oriented Multimedia Content Distribution

With the rapid development of wireless communication technologies and the popularization of smart terminal devices,a variety of mobile multimedia services are gradually springing up,which leads to an explosive growth in mobile network traffic.Cisco reports that video traffic will account for more than 80 percent of global mobile traffic by 2022.It can be seen that video services have become the killer application of the current mobile Internet.In this context,the increasing mobile data traffic and the limited network carrying capacity have become the primary contradiction that hinders the development of the current mobile Internet.The above situation will definitely require the mobile network to have more excellent service performance in the future.Therefore,it is greatly significant to actively carry out research on fifth-generation mobile communication technology(5G).However,the strategy of blindly upgrading hardware not only imposes huge expenses on operators but also makes it difficult to catch up with the exponential growth of video services.On the other hand,as one of the most critical technologies to support mobile Internet,the content distribution is the key to promoting the realization of high-quality multimedia services on 5G networks.Based on the existing work,this thesis focuses on how to provide mobile users with high-quality multimedia services through key technologies of content distribution in 5G networks.The research work is carried out from two aspects:the content delivery and computing unloading of the user terminal side,the resource scheduling and service optimization of the network side.Specifically,the research contents include:(1)multimedia content collaborative delivery mechanism in 5G vehicular networks;(2)edge offloading strategy for multimedia computing tasks in 5G networks;(3)online scheduling mechanism for multimedia resources in 5G dense networks;(4)price game optimization method based on credible multimedia services in 5G cloud networks.Based on the above four aspects,this thesis formed a set of 5G network multimedia content distribution key technology research architecture.The detailed research contents are summarized as follows:(1)In the aspect of content delivery in 5G vehicular networks,in order to solve the problems of resource fragmentation distribution and low multimedia delivery efficiency caused by the instability of transmission links in the Internet of Vehicles,this thesis proposes a multimedia content collaborative delivery mechanism in 5G vehicular networks.Firstly,based on the social characteristics of mobile multimedia services,the virtual family with similar behavior of users is constructed by analyzing the mobile similarity and preference similarity of vehicle users.Furthermore,based on the recognition of user behavior,a family unicast routing method is proposed to realize the nearby acquisition of video content.Moreover,a pricing-based caching strategy is constructed to accurately optimize the cache resource distribution of vehicle nodes.Finally,simulation results verify that the proposed method has superior performance in terms of video service quality.(2)In the aspect of task offloading in 5G edge networks,this thesis studies an edge offloading strategy for multimedia computing tasks to the problem that the limited computing and battery capacity of terminal equipment could not meet the demand for compute-intensive multimedia services.First,the overhead model of multimedia computing service is constructed by combining the computing resources of edge BS,fog computing node and terminal devices.Secondly,fully considering the effect of wireless channel transmission interference during the offloading process,a multi-user computing offloading game strategy is proposed,and the Nash equilibrium is proved by constructing it as a potential game.Furthermore,a distributed offloading and resource allocation algorithm is designed to solve the overhead optimization problem of multimedia computing services.Finally,the superiority of the proposed method in service overhead is verified by simulation experiments.(3)In the aspect of resource scheduling in dense 5G networks,an online scheduling mechanism for multimedia resources is studied to solve the problems of single access mode in wireless networks and lack of coordination among heterogeneous dense BSs.Firstly,a joint optimization objective is proposed to maximize the system throughput and minimize the energy consumption.On this basis,a nonlinear multi-dimensional joint optimization problem is constructed by considering the constraints of user experience quality and system stability.Furthermore,a new Lyapunov stochastic optimization theory is utilized to decouple this problem.Specifically,it can be decomposed into three subproblems that are easy to solve.i.e.,QoE based access control,cooperative resource allocation and multimedia service scheduling,and then the corresponding solving algorithms are designed,respectively.Finally,the performance advantages of the proposed method are verified by simulation experiments.(4)In the aspect of service optimization in 5G cloud networks,in view of service security and cost-effectiveness in hybrid cloud platform,a price game optimization method based on credible multimedia services in 5G cloud networks is studied.Firstly,a trusted service platform discrimination mechanism is proposed by establishing the direct credibility and indirect credibility models.Secondly,a blockchain-based credibility detection method is proposed,which ultilizes the smart contract technology to audit the video possession records.Furthermore,a Stackelberg game model based on credibility and service pricing is constructed to maximize the utility between the 5G clouds and mobile users.In addition,the game equilibrium is achieved by designing a gradient descent method.Finally,simulation experiments verify the effectiveness of the proposed method in terms of service reliability and pricing utility.In summary,this thesis focuses on the key technologies of multimedia content distribution in 5G networks,and conducts the systematic study on four aspects,including:multimedia content delivery,computing task offloading,online resource scheduling,and credible service optimization.In this way,the whole content distribution system is organically combined,which has certain theoretical novelty and application value.In terms of study method,this thesis follows the research ideas of related work analysis,model construction,algorithm design and simulation experiments.In terms of data analysis,this thesis focuses on the actual index of multimedia services in 5G networks and verifies the superior performance of the proposed methods.The above research has effectively solved the key scientific issues of the multimedia distribution in 5G networks,and promoted the development of mobile multimedia services in the future.