  An emerging trend of next generation communication systems is to provide
network edges with additional capabilities such as storage resources in the
form of caches to reduce file delivery latency. To investigate the impact of
this technique on latency, we study the delivery time of a cache-aided
broadcast-relay wireless network consisting of one central base station, $M$
cache-equipped transceivers and $K$ receivers under finite precision channel
state information (CSI). We use the normalized delivery time (NDT) to capture
the worst-case per-bit latency in a file delivery. Lower and upper bounds on
the NDT are derived to understand the influence of $K,M$, cache capacity and
channel quality on the NDT. In particular, regimes of NDT-optimality are
identified and discussed.
