How Agile is the Adaptive Data Rate Mechanism of LoRaWAN?

TL;DR

This paper analyzes the performance of LoRaWAN's Adaptive Data Rate mechanism, revealing its slow adaptation to changing link conditions and exploring parameter adjustments to improve convergence speed.

Contribution

The study provides a detailed performance analysis of LoRaWAN's ADR mechanism and investigates how parameter tuning can enhance its agility.

Findings

ADR lacks quick adaptability to link changes

Convergence to reliable state takes hours to days

Parameter adjustments can improve adaptation speed

Abstract

The LoRaWAN based Low Power Wide Area networks aim to provide long-range connectivity to a large number of devices by exploiting limited radio resources. The Adaptive Data Rate (ADR) mechanism controls the assignment of these resources to individual end-devices by a runtime adaptation of their communication parameters when the quality of links inevitably changes over time. This paper provides a detailed performance analysis of the ADR technique presented in the recently released LoRaWAN Specifications (v1.1). We show that the ADR technique lacks the agility to adapt to the changing link conditions, requiring a number of hours to days to converge to a reliable and energy-efficient communication state. As a vital step towards improving this situation, we then change different control knobs or parameters in the ADR technique to observe their effects on the convergence time.