  NB-Fi is a new low-power wide-area network technology, which has become
widely used for smart cities, smart grids, the Industrial Internet of Things,
and telemetry applications. Although many countries use NB-Fi, almost no papers
study NB-Fi, and its peak performance is unknown. This article aims to fill
this gap by analyzing this technology and studying the problem of rate
assignment in NB-Fi networks. For that, this article develops a mathematical
model used to find the packet loss ratio, packet error rate, and the average
delay for various rate assignment approaches. The performance evaluation
results are used to develop the guidelines for NB-Fi configuration to optimize
the network performance.
