Title: Multi-Antenna Coded Caching,
Abstract: In this paper we consider a single-cell downlink scenario where a
multiple-antenna base station delivers contents to multiple cache-enabled user
terminals. Based on the multicasting opportunities provided by the so-called
Coded Caching technique, we investigate three delivery approaches. Our baseline
scheme employs the coded caching technique on top of max-min fair multicasting.
The second one consists of a joint design of Zero-Forcing (ZF) and coded
caching, where the coded chunks are formed in the signal domain (complex
field). The third scheme is similar to the second one with the difference that
the coded chunks are formed in the data domain (finite field). We derive
closed-form rate expressions where our results suggest that the latter two
schemes surpass the first one in terms of Degrees of Freedom (DoF). However, at
the intermediate SNR regime forming coded chunks in the signal domain results
in power loss, and will deteriorate throughput of the second scheme. The main
message of our paper is that the schemes performing well in terms of DoF may
not be directly appropriate for intermediate SNR regimes, and modified schemes
should be employed.