  To improve signal-to-interference ratio (SIR) and make better use of file
diversity provided by random caching, we consider two types of linear
receivers, i.e., maximal ratio combining (MRC) receiver and partial zero
forcing (PZF) receiver, at users in a large-scale cache-enabled single-input
multi-output (SIMO) network. First, for each receiver, by utilizing tools from
stochastic geometry, we derive a tractable expression and a tight upper bound
for the successful transmission probability (STP). In the case of the MRC
receiver, we also derive a closed-form expression for the asymptotic outage
probability in the low SIR threshold regime. Then, for each receiver, we
maximize the STP. In the case of the MRC receiver, we consider the maximization
of the tight upper bound on the STP by optimizing the caching distribution,
which is a non-convex problem. We obtain a stationary point, by solving an
equivalent difference of convex (DC) programming problem using concave-convex
procedure (CCCP). We also obtain a closed-form asymptotically optimal solution
in the low SIR threshold regime. In the case of the PZF receiver, we consider
the maximization of the tight upper bound on the STP by optimizing the caching
distribution and the degrees of freedom (DoF) allocation (for boosting the
signal power), which is a mixed discrete-continuous problem. Based on
structural properties, we obtain a low-complexity near optimal solution by
using an alternating optimization approach. The analysis and optimization
results reveal the impact of antenna resource at users on random caching.
Finally, by numerical results, we show that the random caching design with the
PZF receiver achieves significant performance gains over the random caching
design with the MRC receiver and some baseline caching designs.
