Mobility-Aware Caching Strategy in an SDN-Based Cooperative Caching Network

作     者：Qi Li Xiaoxiang Wang Dongyu Wang Qi Li;Xiaoxiang Wang;Dongyu Wang

作者机构：Information and Communication EngineeringBeijing University of TechnologyBeijing 100124China Beijing University of Posts and TelecommunicationsBeijing 100876China 

出 版 物：《中国通信:英文版》 (China Communications)

年 卷 期：2023年第20卷第9期

页      面：196-214页

核心收录：

学科分类：0810[工学-信息与通信工程] 08[工学] 0812[工学-计算机科学与技术（可授工学、理学学位）] 

基　　金：the Beijing Natural Science Foundation under Grant NO.L222039. 

主　　题：wireless caching mobility SDN 

摘      要：The upsurge of mobile multimedia traf-fic puts a heavy burden on the cellular network,and wireless caching has emerged as a powerful tech-nique to overcome the backhaul bottleneck and al-leviate the network burden.However,most previ-ous works ignored user mobility,thus not reaping the caching gain from user mobility and having lim-ited practical applications.In this paper,a mobility-aware caching strategy for the software-defined net-work(SDN)-based network is studied.Firstly,since typical mobile user(MU)has multiple opportunities to connect with the nearby MUs and Small-base stations(SBSs),the contact times between MUs as well as be-tween MU and SBSs are derived as the Poisson distri-bution and Gamma distribution.Secondly,we propose a two-tier cooperative caching strategy,where SBSs cache the rateless Fountain code encoded video blocks probabilistically and nonrepeatedly while MUs just store the whole encoded video received last time.The corresponding four-stage transmission process is ana-lyzed,where the key intermediate step is the deriva-tion of the service and the failing probabilities of each transmission manner.Finally,we derive the success-ful offloading rate and average data offloading ra-tio(ADOR)as performance metrics.A system op-timization problem based on ADOR is formulated,and two solutions are proposed,namely,derivativebased solution(DB-Solution)and long-tail distribution approximation(LTD-Approximation).Simulation results demonstrate that the effectiveness of LTDApproximation is similar to the DB-Solution,and the proposed caching strategy can achieve quasi-optimal performance compared with other contrast schemes.