Virtual caching with apportioned objects for mobile virtual reality

Abstract

We consider a content-caching system for Virtual or Augmented Reality (VR/AR) that is shared by a number of user groups. The cache could be located in an edge–cloud datacenter and the users could be mobile. Each user group operates its own LRU-list of a certain capacity in the shared cache. The length of objects simultaneously appearing in plural LRU-lists is equally divided (apportioned) among them, i.e., object sharing among the LRUs. We provide a working-set approximation for this system to quickly estimate the cache-hit probabilities for objects apportioned across user groups. We also prove that a solution to the working-set approximation exists. A way to reduce ripple evictions is discussed and some numerical performance results are provided based on Zipf-distributed object popularities. To evaluate our apportioned object sharing system in a VR context, we introduce a benchmark specifically designed for VR streaming, addressing the latency and Quality of Experience (QoE) challenges that arise due to VR’s dynamic fields of view (FoVs) and user synchronization requirements. Using the VR benchmark, we present additional numerical results for cache-hit rates and users’ QoE to illustrate the system’s effectiveness under VR streaming conditions.