วิธีการอัพเดตคอนเทนต์ในเฟมโตแคชชิง

Abstract

Nowadays, many wireless communication systems widely use small base stations to reduce request loads from only a single base station. There is anapproach called FemtoCachingthatpropose the small base stations to cache contents. These small base stations are called helpers. In addition, an approximation algorithm for placing contents in caches of the helpers in order that the users connectingto multiple helpers can see contents as many as possible is also proposed. However, this approach does not consider changes of content ranking and content popularities that change during time. Hence, contents in helpers should be updated correspondingly to the current content ranking with limited number of updated contents. The algorithm of the FemtoCaching is not suitable for updating because its complexity is high. In this research, we propose 2 new updating methods with limited number of updated contents. They are popularity-based method and rank-based updating method. The complexity of both methods are lower than the algorithm of the FemtoCaching. An order of helpers to be updated is sorted by their priority scores. The helper with the most priority score is firstly updated. The performances are evaluated by the simulation. The results show that the proposed methods have acceptable performances. The popularity-based updating method has acceptable performance in case of low limited threshold of updated contents. The rank-based updating method has acceptable performance in case of high limited threshold of updated contents.