Load-based Content Allocation Scheme for Realizing Efficient Mobile Cooperative Cache

Abstract

Owing to the rise in mobile users accessing high-quality video content, content delivery networks are under increased load. Therefore, a distributed cooperative caching technique, in which each mobile device functions as a cache server and shares a cache through device-to-device communication has been proposed to alleviate the network load. However, efficient content placement on mobile devices is challenging, because the cache capacity of each mobile device is limited and did not remain at a fixed location. In this study, we propose a load-based content allocation (LBCA) method that efficiently distributes cache data to mobile devices based on the load of the base station (BS). The proposed scheme uses scalable video coding (SVC) that subdivides the content data hierarchically and dynamically selects the video quality depending on the network load. Additionally, we propose a multi-stage LBCA (M-LBCA) that divides the BS distribution area into concentric clusters to efficiently manage cache capacity for SVC data while considering the distance from the BS. Simulations demonstrated a decrease in the total number of users unable to continually view content on congested networks when using LBCA and M-LBCA as compared to the existing method in four evaluation environments. Therefore, our experiments demonstrate that the proposed cache control scheme improved the user’s quality of experience.