Evaluating the Performance of eMTC and NB-IoT for Smart City Applications

TL;DR

This paper compares eMTC and NB-IoT, two LPWAN technologies, in terms of energy efficiency, latency, and scalability for smart city applications, providing models and simulations to evaluate their performance.

Contribution

The paper introduces analytical models for energy consumption and latency, and evaluates the performance of eMTC and NB-IoT through simulations, highlighting their suitability for smart city deployments.

Findings

Both technologies can achieve 8 years battery life in poor coverage.

eMTC supports more devices than NB-IoT.

eMTC offers latency 10 times lower than NB-IoT.

Abstract

Low power wide area network (LPWAN) is a wireless telecommunication network that is designed for interconnecting devices with low bitrate focusing on long range and power efficiency. In this paper, we study two recent technologies built from existing Long-Term Evolution (LTE) functionalities: Enhanced machine type communications (eMTC) and Narrow band internet of things (NB-IoT). These technologies are designed to coexist with existing LTE infrastructure, spectrum, and devices. We first briefly introduce both systems and then compare their performance in terms of energy consumption, latency and scalability. We introduce a model for calculating the energy consumption and study the effect of clock drift and propose a method to overcome it. We also propose a model for analytically evaluating the latency and the maximum number of devices in a network. Furthermore, we implement the main functionality of both technologies and simulate the end-to-end latency and maximum number of devices in a discrete-event network simulator NS-3. Numerical results show that 8 years battery life time can be achieved by both technologies in a poor coverage scenario and that depending on the coverage conditions and data length, one technology consumes less energy than the other. The results also show that eMTC can serve more devices in a network than NB-IoT, while providing a latency that is 10 times lower.