Energy performance of LR-FHSS: analysis and evaluation

TL;DR

This paper models the energy consumption of LR-FHSS in LoRaWAN, revealing potential battery lifetimes of up to 16 years with optimal configurations and providing insights into its energy efficiency compared to traditional LoRa.

Contribution

It presents the first analytical energy consumption model for LR-FHSS, based on real hardware measurements, highlighting its potential for long battery life with proper tuning.

Findings

LR-FHSS can achieve up to 2.5 years battery life at 50-minute notifications.

Optimal configuration can extend lifespan to 16 years with daily notifications.

LR-FHSS may have higher energy consumption than LoRa, but can be optimized for long-term use.

Abstract

Long-range frequency hopping spread spectrum (LR-FHSS) is a pivotal advancement in the LoRaWAN protocol that is designed to enhance the network's capacity and robustness, particularly in densely populated environments. Although energy consumption is paramount in LoRaWAN-based end devices, {this is the first study} in the literature, to our knowledge, that models the impact of this novel mechanism on energy consumption. In this article, we provide a comprehensive energy consumption analytical model of LR-FHSS, focusing on three critical metrics: average current consumption, battery lifetime, and energy efficiency of data transmission. The model is based on measurements performed on real hardware in a fully operational LR-FHSS network. While in our evaluation, LR-FHSS can show worse consumption figures than LoRa, we find that with optimal configuration, the battery lifetime of LR-FHSS end devices can reach 2.5 years for a 50 min notification period. For the most energy-efficient payload size, this lifespan can be extended to a theoretical maximum of up to 16 years with a one-day notification interval using a cell-coin battery.