Decentralized Coded Caching for Shared Caches

The demands of the clients in the client-server framework exhibit temporal variance leading to congestion in the network at random intervals. To alleviate this problem, popular data is loaded in cache memories scattered across the network. In the conventional cache framework, each user has an associated cache and cache loading is centrally coordinated. For large networks, a more practical approach is to make the loading of the caches decentralized. This letter considers the shared caching problem in which each cache can serve multiple clients. A new and optimal delivery scheme is proposed for the decentralized shared caching problem. The delivery scheme is shown to be optimal among all linear schemes, using techniques from index coding. It is shown that the rate achieved by the proposed scheme is comparable to the existing scheme which uses centralized prefetching.