Research On Joint Optimization Of Cache And Transmission For Wireless Networks

In recent years,smart devices represented by smart phones have provided an ever-increasing variety of applications.The demand for data and multimedia services anywhere over the wireless network has increased dramatically.In order to solve the explosive growth of mobile data services,efficient content caching and transmission technologies aimed at significantly reducing redundant data transmission and improving content delivery efficiency have attracted great attention from scholars.By caching content that users often require in small base stations or user storage device,when the user requires a file,the small base station or user device with the required file can service the user directly without having to go through the core network.In this way,it can reduce transmission delay,reduce the burden of backhaul link and reduce network congestion.This paper focus on the joint optimization strategy of content caching and transmission in wireless networks,mainly including the following two aspects:Firstly,we consider a two-tier cellular heterogeneous network(HetNets),contents with different user preference are cached in the base station.When a user makes a request for a file,the base station that caches the file near the user can directly serve the user or download through the core network firstly.In order to minimize the energy consumption of the whole network,a joint content caching and content delivery optimization strategy is proposed.Considering the coupling multiplicative variables,we utilize the alternative optimization(AO)algorithm to decompose the original problem into content caching and delivery subproblems.Besides,a distribution algorithm is used for optimization to reduce the computational complexity.The simulation results show that compared with other algorithms,the proposed algorithm achieves lower energy consumption.Secondly,in vehicular ad-hoc network,the contents are cached in the roadside unit(RSU)and vehicles also have limited cache space to be able to cache some contents.In order to reduce the transmission burden of itself,RSU encourages vehicles to transfer contents to each other.In order to maximize the benefits of both the vehicle and the RSU,a Stackelberg game analysis method based on the Q-learning algorithm is proposed to determine whether to transmit by vehicle or RSU.Taking into account the benefits over time to make the best choice,the benefit function solving process of RSU is modeled as Markov decision process and solved by Q-learning algorithm.Finally,the performance of the proposed algorithm is analyzed by matlab,which proves the rationality and effectiveness of the above algorithm.Finally,we summarize the work of the entire article and explain the direction of future work.