FemtoCaching: Wireless Video Content Delivery Through Distributed Caching Helpers
The authors propose and analyze a novel way for increasing the area spectral efficiency of video transmission in cellular communications systems. Small base stations called helpers with low-rate backhaul but high storage capacity cache popular video files. Mobile stations requesting video files receive them via short-range transmissions from helpers, if they are present in their caches; files not available from helpers are transmitted by the base station. They analyze the optimum way of assigning files to the different helpers, in order to minimize the expected file downloading time for files. They distinguish between the un-coded case (where only complete files are stored) and the coded case, where segments of Fountain-encoded versions of the video files are stored at helpers.