Cache Aided Communications with Multiple Antennas at Finite SNR

TL;DR

This paper introduces a cache-aided MIMO communication scheme at finite SNR that optimizes cache allocation and transmission strategies to improve throughput and fairness in multi-user cellular networks.

Contribution

It formulates cache-aided MIMO communication as a linear program and derives a closed-form solution for a special case, enhancing throughput and fairness.

Findings

The proposed scheme outperforms previous methods by serving users at their own channel rates.

A closed-form solution for specific parameters balances fairness and throughput.

Cache helps in balancing user rates, achieving fairness without sacrificing network capacity.

Abstract

We study the problem of cache-aided communication for cellular networks with multi-user and multiple antennas at finite signal-to-noise ratio. Users are assumed to have non-symmetric links, modeled by wideband fading channels. We show that the problem can be formulated as a linear program, whose solution provides a joint cache allocation along with pre-fetching and fetching schemes that minimize the duration of the communication in the delivery phase. The suggested scheme uses zero-forcing and cached interference subtraction and hence allow each user to be served at the rate of its own channel. Thus, this scheme is better than the previously published schemes that are compromised by the poorest user in the communication group. We also consider a special case of the parameters for which we can derive a closed form solution and formulate the optimal power, rate and cache optimization. This special case shows that the gain of MIMO coded caching goes beyond the throughput. In particular, it is shown that in this case, the cache is used to balance the users such that fairness and throughput are no longer contradicting. More specifically, in this case, strict fairness is achieved jointly with maximizing the network throughput.