Research On Edge Caching For Rail Traffic

Rail transit,such as subway,has become a popular mean for traveling,and it is common to use mobile terminals to connect Internet services.The huge passenger flow generates a serious challenge to the mobile network service.How to improve the users' experience becomes a hot issue.Edge caching is one of the most important ways to solve this issue.In this paper,we propose a proactive caching strategy,based on the characteristics of rail transit system with fixed track.According to the users' network access history,the content that user might acquire is prefetched and cached at the base stations,such that the cache hit ratio is increased,and the delay is reduced.Considering the contradiction between the cache capacity and the access amount,we first established a cost model.It contains the caching cost that represent the cached content,and the waiting cost represent the missed request.Secondly,based on the characteristics of linear topology and the relevance of user access content,we model the caching probability between cache content and base station with Markov chain.Then,we solve the problem of minimizing the cost.Finally,compared with LFU(Least frequently used)strategy and the random caching strategy,the cache hit ratio increases 84.34% and 190%,and the total delay decreases by 26.22% and 39.92%.