A Simplistic View on Latency of Random Access in Cellular Internet of Things

It is important for an IoT device to be able to access the network with no or small delay in order to send its data to the Internet quickly. Particularly, in real time applications that time is of the essence, this delay should be small. The period of time from when an IoT device initiates a Random Access (RA) process to get access to the network until it sends its data is called the latency. Since the latency is dependent on the number of IoT devices in the network, the way that each device generates its traffic, and many other factors, it is extremely challenging to accurately estimate the latency. In this paper, we provide a simplistic view to estimate the latency in various situations based on the number of collisions, repetition, and data size for various RA processes belonging to different Cellular Internet of Things (CIoT) technology enhancements. To simplify the situation, we only discuss the most important factors. This simplistic view gives the reader a sense of the trimming of different parts of the RA process without using a complex simulator or analytical model.