An Analytical Model for Evaluating the Interplay Between Capacity and Energy Efficiency in NB-IoT

International audienceThe Narrowband Internet Of Things, better known by the acronym NB-IoT, is spearheading 3GPP’s effort to address the massive Machine Type Communication (mMTC) segment of 5G. With 103 deployments in more than 40 countries, NB-IoT’s performance in terms of cell capacity and coverage is well established. However, the performance it can offer in terms of battery life, a foundational requirement of IoT, has received little attention. In this paper, we introduce the first theoretical model based on the M/D/H/K queues capable of evaluating the energy performance of NB-IoT in advanced cell scenarios defined by a coverage distribution, a payload uplink and downlink size, and an incoming communication rate. After using the values computed by 3GPP for single-terminal cells to demonstrate its accuracy, we use our model to evaluate the NB-IoT’s energy performance. Our analysis reveals that a) Early Data Transmission, originally designed for improving the latency and connection density, can also significantly improve the energy performance, and b) When the load in multi-terminal cell settings increases, the terminal battery lifetime collapses. Leveraging our model, we introduce a solution requiring no changes to the standard and show that it significantly improves the terminal battery life