Research On Communication Scheme And Caching Strategy Based On D2D

Edge computing(MEC)not only supports efficient data transmission and caching functions,but also provides sufficient computing power to significantly reduce latency and system energy consumption by sinking cloud computing functions to the edge of the network.D2 D communication assisted by network is one of the key technologies in 5G.In the network assisted D2 D framework,two devices(i.e.mobile stations/cellular users)can directly communicate with each other without the need for network infrastructure such as base stations(BS)and core networks.In addition,edge cellular users can also improve throughput and performance based on D2 D links.Based on the theory of resource allocation and content caching,this paper studies the communication scheme and content caching strategy of D2 D collaborative edge computing.Firstly,we studied the MEC communication scheme,and here we mainly focus on resource allocation for D2 D communication.The application of Non orthogonal Multiple Access(NOMA)in LTE networks can enhance network capacity and Spectral efficiency.Introducing NOMA technology to share the spectrum resources of cellular users in D2 D communication can alleviate the current shortage of spectrum resources,but it will also introduce interference between D2 D users and cellular users.This article proposes a research scheme for sharing D2 D users and cellular users based on NOMA technology,using a one-to-two resource allocation mode,where two pairs of D2 D users share the spectrum resources of one cellular user,and SIC technology is used to eliminate interference between cellular and D2 D users.This solution not only optimizes the throughput of the system,but also enhances the performance of edge users.The simulation results show that the communication scheme between D2 D users and cellular users based on NOMA outperforms traditional cellular priority allocation,IMR resource allocation,and interference control schemes in terms of system average throughput and edge user average throughput.Secondly,the caching strategy of MEC-D2 D was studied.D2 D content caching and MEC content caching can improve explosive traffic demands and enhance user experience.Information age is an important concept for measuring the timeliness of information,which can improve the accuracy and reliability of the system.Currently,information age has not been taken into account in research on D2 D and MEC caching.Therefore,this article proposes a D2 D and MEC caching strategy based on information age,which increases information freshness(quantified by AOI)on the basis of cached content to update cache content.This can greatly improve cache efficiency(quantified by cache hit rate)and further improve the performance of edge caching.For this technology,a placement scheme for caching dynamic content items is first proposed.The dynamic content items here represent a comprehensive consideration of content updates and popularity,and the cache hit rate is calculated based on popularity and content age.After analyzing the cache hit rate,appropriate content is selected for placement;Secondly,an age constrained content access strategy was proposed to achieve optimal energy efficiency in D2 D and MEC assisted wireless caching systems.The proposed problem is a Markov Decision Making(MDP)process problem,which achieves optimal energy efficiency by solving the problem.Simulation shows that our proposed scheme has significant advantages over traditional D2 D caching schemes in terms of cache hit rate,average age of content,and average system energy consumption.