Edge Caching: On the Performance of Placement and Delivery Coding Schemes

We study the performance of caching schemes based on two different coding techniques. A heterogeneous network is assumed, in which cache-aided relays are connected through a backhaul link to a primary node while no connection exits between users and the primary node. The first caching scheme considers to fill the cache with encoded content while the second scheme considers to encode the content during the delivery phase. We compare the schemes by characterizing the average transmission load when users ask for downloading content to the network. We provide an approximation of the expression of the average load which allows a fast evaluation of the network behavior for each scheme considered. We further assume a constraint on the capacity of the backhaul link and derive the expression of the outage probability, i.e. the probability that the system is not able to serve the entire set of users demands. Finally, we examine and discuss how the derived analysis of a two relays scenario can be scaled to study the performance of a network with a generic number of relays.