This work explores a multiple transmit antenna setting in a multi-access
coded caching (MACC) network where each user accesses more than one cache. A
MACC network has K users and K caches, and each user has access to r<K
consecutive caches in a cyclic wrap-around manner. There are L antennas at
the server, and each cache has a normalized size of M/N≤1. The cyclic
wrap-around MACC network with a single antenna at the server has been a
well-investigated topic, and several coded caching schemes and improved lower
bounds on the performance are known for the same. However, this MACC network
has not yet been studied under multi-antenna settings in the coded caching
literature. We study the multi-antenna MACC problem and propose a solution for
the same by constructing a pair of arrays called caching and delivery arrays.
We present three constructions of caching and delivery arrays for different
scenarios and obtain corresponding multi-antenna MACC schemes for the same. Two
schemes resulting from the above constructions achieve optimal performance
under uncoded placement and one-shot delivery. The optimality is shown by
matching the performance of the multi-antenna MACC scheme to that of an optimal
multi-antenna scheme for a dedicated cache network having an identical number
of users, and each user has a normalized cache size of rM/N. Further, as a
special case, one of the proposed schemes subsumes an existing optimal MACC
scheme for the single-antenna setting.Comment: 11 pages (double column), 3 Figure