Routing-Based Delivery in Combination-Type Networks with Random Topology

The coded caching scheme proposed by Maddah-Ali and Niesen (MAN) transmits coded multicast messages to users equipped with caches and it is known to be optimal within a constant factor. This work extends this caching scheme to two-hop relay networks with one main server with access to a library of N files, and H relays communicating with K users with cache, each of which is connected to a random subset of relays. This topology can be considered as a generalized version of a well-known family of networks, referred to as combination networks. Our approach is simply based on routing MAN packets through the network. The optimization of the routing can be formulated as a Linear Program. In addition, in order to reduce the computational complexity, a divide and conquer greedy algorithm is proposed to approach the linear program solution. Numerical simulations show that the proposed scheme outperforms the existing caching schemes for this class of networks.