Enhancing Mobile Video Capacity and Quality Using Rate Adaptation, RAN Caching and Processing

Adaptive Bit Rate (ABR) streaming has become a popular video delivery technique, credited with improving Quality of Experience (QoE) of videos delivered on wireless networks. Recent independent research reveals video caching in the Radio Access Network (RAN) holds promise for increasing the network capacity and improving video QoE. In this paper, we investigate opportunities and challenges of combining the advantages of ABR and RAN caching to increase the video capacity and QoE of the wireless networks. While each ABR video is divided into multiple chunks that can be requested at different bit rates, a cache hit requires the presence of a specific chunk at a desired bit rate, making ABR-aware RAN caching challenging. To address this without having to cache all bit rate versions of a video, we propose adding limited processing capacity to each RAN cache. This enables transrating a higher rate version that may be available in the cache, to satisfy a request for a lower rate version, and joint caching and processing policies that leverage the backhaul, caching, and processing resources most effectively, thereby maximizing video capacity of the network. We also propose a novel rate adaptation algorithm that uses video characteristics to simultaneously change the video encoding and transmission rate. The results of extensive statistical simulations demonstrate the effectiveness of our approaches in achieving significant capacity gain over ABR or RAN caching alone, as well as other ways of enabling ABR-aware RAN caching, while improving video QoE.