  In this paper we address the problem of resource allocation for alarm traffic
in industrial Internet of Things networks using massive MIMO. We formulate the
general problem of how to allocate pilot signals to alarm traffic such that
delivery is guaranteed, while also minimising the number of pilots reserved for
alarms, thus maximising the channel resources available for other traffic, such
as industrial control traffic. We present an algorithm that fulfils these
requirements, and evaluate its performance both analytically and through a
simulation study. For realistic alarm traffic characteristics, on average our
algorithm can deliver alarms within two time slots (of duration equal to the 5G
transmission time interval) using fewer than 1.5 pilots per slot, and even in
the worst case it uses around 3.5 pilots in any given slot, with delivery
guaranteed in an average of approximately four slots.
