面向无线边缘缓存的文件库大小分析  

File Catalogue Size Analysis for Wireless Edge Caching

作　　者：鲁益明 谭笑封 韩圣千[1] 杨晨阳[1] Lu Yiming;Tan Xiaofeng;Han Shengqian;Yang Chenyang(Beihang University,Beijing 100191,China)

机构地区：[1]北京航空航天大学

出　　处：《信号处理》2019年第4期549-555,共7页Journal of Signal Processing

基　　金：国家自然科学基金项目(61871015)

摘　　要：文件库大小对无线边缘缓存的性能具有重要的影响。本文基于Zipf文件流行度模型,分析了文件库大小与用户请求数、流行度参数等因素的渐近关系。研究结果表明,当用户请求数较少时,文件库大小随请求数线性增长,而当请求数较多时,文件库大小随请求数呈负指数增长,这一结论适用于不同的流行度参数。仿真结果验证了所分析结果的准确性,并基于校园网中采集的典型视频网站请求记录验证了分析结果的有效性。在实际系统中,无线边缘节点覆盖范围内的用户请求数通常远小于视频网站的文件总数,因此用户请求的文件库大小随请求数线性增长,而非文献中猜测的亚线性增长,这对提升无线边缘缓存性能带来严峻挑战。File catalogue size has a large impact on the performance of wireless edge caching.Based on the Zipf file popularity model,this paper analyzes the asymptotic relationship between the file catalogue size and the number of user requests and the popularity parameters.The analytical results show that,when the number of requests is small,the size of the file catalogue increases linearly with the number of requests,and when the number of requests is large,the size of the file catalogue increases in a negative exponential manner with the number of requests.The results are valid for different popularity parameters.The accuracy and validity of the obtained analytical results are verified by simulations and a real dataset for a typical video website collected in a campus network.In practical systems,the number of requests within the coverage of a wireless edge node is usually much smaller than the total number of files on a video website.Therefore,the size of the file catalogue increases linearly with the number of requests,rather than the sublinear growth conjectured in the literature.This poses a serious challenge for wireless edge caching.

关 键 词：文件库大小 无线边缘缓存 文件流行度 视频点播 

分 类 号：TN929.53[电子电信—通信与信息系统]