Efficient Pilot Allocation for URLLC Traffic in 5G Industrial IoT Networks

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. In the average case our algorithm can deliver alarms within two time slots (of duration equal to the 5G transmission time interval) using fewer than two pilots per slot, and even in the worst case uses at most eight pilots in any given slot, with delivery guaranteed in less than four slots.