Energy performance of LR-FHSS: analysis and evaluation

TL;DR

While in the authors' evaluation, LR-FHSS can show worse consumption figures than LoRa, it is found that with optimal configuration, the battery lifetime of LR-FHSS end devices can reach 2.5 years for a 50 min notification period, and the most energy-efficient payload size.

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.

Figures (16)

• Figure S1: LoRaWAN network architecture.
• Figure S2: Class A operation with one uplink transmission followed by two receive windows.
• Figure S3: LoRaWAN MAC frame structure.
• Figure S4: LR-FHSS PHY frame structure.
• Figure S5: Experimental scenario for measuring the current consumption of the considered LR-FHSS ED.