Research On Energy-efficient Content Placement And Coded Transmission For Edge Cache-enabled Networks

With the increasing of mobile applications and multimedia services,the traffic of popular content data keeps surging,and cloud computing has been unable to meet the growing demand of users for high-quality experience services.By providing caching and computing at the network edge,mobile edge computing can effectively reduce the load of the cloud server 's backhaul link,thus becoming the inevitable trend of the future 6G network architecture.At the same time,the problem of high energy consumption caused by data transmission in edge cache-enabled networks(ECNs)has gradually attracted the attention of academia and industry.Res earchers have been looking for high energy efficiency content caching methods for ECNs to meet the service demand of green communication network in the future.Coded caching has potential application value to improve network performance for high energy-efficient in ECNs.The server multicast the coded content to multiple devices simultaneously,which significantly reduces the amount of data in the core network.However,on the one hand,the heterogeneity of system parameters increases the difficulty of content placement and coded multicast opportunity creation between different edge devices;On the other hand,the transmission sequence of the content at different levels directly affects the transmission energy consumption of the system.To solve the problem of the above-mentioned two aspects,the goal of this article is to reduce the total energy consumption,studies the coded caching in heterogeneous,hierarchical ECNs adaptability problems,focus on different levels of cache content deployment and sequence coded multicast scheme design,maximize the coded multicast opportunity.The main research contents are summarized as follows:Firstly,the basic theory of the coded caching is introduced.The single-layer coded caching model and the upper and lower bounds of memory-rate tradeoff are analyzed in detail,and through simulation found that the coded caching significantly reduces the data transmission rate compared with the uncoded caching.The paper further introduces the theoretical knowledge of hierarchical cod ed caching,finds that the compromise between applying single-layer coded caching scheme directly between each layer and applying cross-layer coded caching scheme between server and user can minimize the data transmission rate.Aiming at the ECNs scenario with heterogeneous and hierarchical,an coded transmission strategy of joint optimization of content placement matrix and cache capacity vector of edge base stations(EBSs)is proposed.Based on the analysis of EBSs cache and transmission model,the closed expression of total energy consumption is derived.In order to create as many coded multicast opportunities as possible for the macro base station(MBS),a minimization total energy consumption problem based on optimized content placement matrix,cache capacity vector allocation of EBSs is established.The original optimization problem is divided into two sub-optimization problems,and corresponding optimization algorithms are proposed respectively.The simulation results show that our proposed strategy,the total energy consumption is better than that of the traditional random or most popular content placement and uncoded transmission strategies.Aiming at EBSs and users collaborative ECNs scenario,the optimal transmission sequence of MBS and EBSs in a hierarchical architecture is proposed.The network model,EBSs and user cache model are established.In order to discuss the influence of transmission order of MBS and EBSs on total energy consumption,the coded transmission model is built in stages.The expression of total energy consumption adapted to the model is analyzed,and in order to maximize the energy consumption advantage of the coded transmission,optimization the content placement matrix of EBSs and the optimization problem with transmission parameter are established.The simulation first determines the transmission sequence of MBS and EBSs,and then compares with other uncoded transmission schemes,and proves the advantage of the coded transmission in the EBSs ans users ECNs in energy consumption.