Edge Cache Replacement Strategy for SVC-Encoding Tile-Based 360-degree Panoramic Streaming

In recent years, with the rapid development of virtual reality (VR), 360-degree panoramic video has grown up to become a popular Internet service. Streaming 360-degree video on today's Internet is challenging due to its ultra-high bandwidth and ultra-low motion-to-photon latency requirements. Although some VR solutions use tiling technology and Scalable Video Coding(SVC) encoding for 360-degree video transmission to reduce bandwidth consumption, it is still being challenging to transmit 360-degree video streams from remote content servers due to network latency. Caching popular video content at the edge of the network can decrease network latency and bandwidth consumption by reducing the number of future requests that have to be sent all the way to remote content servers. Because of the limited cache size, it is essential to decide which content to cache and how to replace the cache when the cache size is insufficient. In this paper, we propose an edge cache replacement strategy named Size-Popularity-Layer-FoV strategy(SPLF) for tile-based 360-degree video streaming using SVC. To improve caching performance, every video chunks' cache value is estimated according to its popularity, size, SVC layer and whether it is in FoV. Simulation results manifest that the proposed strategy can not only improve the hit rate and video quality compared to various baseline algorithms, but also decrease the playback stalls and the duration of rebuffering.