Cache-aided interference management in wireless cellular networks

We consider the problem of interference management in wireless cellular networks with caches at both base stations and receivers and we characterize the degrees-of-freedom (DoF) per cell to within an additive gap of 1 and a multiplicative gap of 2 for all system parameters, under one-shot linear schemes. Our result indicates that the one-shot linear DoF per cell scales linearly with the total amount of cache that is available within each cell. A similar phenomenon had been previously observed for the case of fully-connected wireless networks. Hence, our result demonstrates that it also holds in cellular networks, despite the presence of path loss and fading which results in partial connectivity of the network topology. To establish the result, we propose a randomized and decentralized cache placement and a delivery scheme which, on one hand, utilizes the overlap of contents at base station caches to zero-force part of their outgoing interference, and on the other hand, uses the receiver caches to create coded multicasting opportunities, so that the receivers can eliminate the remaining interference due to undesired packets. We also provide a converse argument to show that our achievable one-shot linear DoF per cell is within an additive gap of 1 and a multiplicative gap of 2 of its optimal value.