Local Content Cloud based Cooperative Caching Placement for Edge Caching

Edge caching can improve the efficiency of content delivery by making full use of the limited storage capacity. Exploiting cooperation between base stations (BSs) could promote the diversity of contents in the whole network and alleviate backhaul traffic. However, prior works mostly overlook the effect of cooperation during caching placement period. In this paper, firstly we propose a local content cloud cooperation scheme to utilize the cache capacity of adjacent BSs. Considering the impact of the capacity of cooperative link and backhaul link, then we formulate an optimizing problem to minimize the average consumption, which consists of content downloading delay and transmission cost. To reduce the complexity and the expenditure of information exchange, we solve the NP-hard problem by the belief propagation method. Meanwhile, simulation shows that the proposed cooperation-based caching placement decreases the average consumption and enhance the hit ratio compared with other strategies.