A Novel Coded Caching Scheme for Partially Cooperative Device-to-Device Networks

Device-to-device (D2D) communication is one of the most promising techniques for future wireless cellular communication systems. This paper considers coded caching in a partially cooperative wireless D2D network, where only a subset of users transmit during delivery, while all users request files. The non-transmitting users are referred to as selfish users. All existing schemes that do not require knowledge of the identity of selfish users before content placement are limited to the high-memory regime, particularly when the number of selfish users is large. We propose a novel coded caching scheme for a partially cooperative D2D network that operates in all feasible memory regimes, regardless of the number of selfish users. We also derive a lower bound on the transmission load of a partially cooperative D2D coded caching scheme. Using this bound, the proposed scheme is shown to be optimal in the high-memory regime.