The Interplay between Index Coding, Caching, and Beamforming for Fog Radio Access Networks

In fog radio access networks, the limited capacity of the fronthaul link is the bottleneck, which renders a high quality of service for video streaming difficult. To circumvent the problem, popular files can be cached in fog access points during off-peak hours. This work points out that beamforming in the access network can be exploited to reduce fronthaul traffic load by a joint design of cache placement scheme at the fog access points and index-coded transmission scheme over the fronthaul. Simulation results show that a percentage reduction of fronthaul traffic by more than 30% can be achieved.