How Can Wake-up Radio Reduce LoRa Downlink Latency for Energy Harvesting Sensor Nodes?

Sensors

卷:21

Michele Magno¹  Antoine Courtay²  NourEl Hoda Djidi²  Olivier Berder²  Matthieu Gautier² 

[1] Department of Information Technology Electrical Engineering, ETH Zürich, 8092 Zurich, Switzerland;

[2] Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), National Centre for Scientific Research (CNRS), University Rennes, 22300 Lannion, France;

关键词: internet of things;    wake-up radio;    LoRa;    heterogeneous networks architecture;    opportunistic cluster heads;    energy harvesting;   

DOI  :  10.3390/s21030733

来源: DOAJ

【 摘 要 】

LoRa is popular for internet of things applications as this communication technology offers both a long range and a low power consumption. However, LoRaWAN, the standard MAC protocol that uses LoRa as physical layer, has the bottleneck of a high downlink latency to achieve energy efficiency. To overcome this drawback we explore the use of wake-up radio combined with LoRa, and propose an adequate MAC protocol that takes profit of both these heterogeneous and complementary technologies. This protocol allows an opportunistic selection of a cluster head that forwards commands from the gateway to the nodes in the same cluster. Furthermore, to achieve self-sustainability, sensor nodes might include an energy harvesting sub-system, for instance to scavenge energy from the light, and their quality of service can be tuned, according to their available energy. To have an effective self-sustaining LoRa system, we propose a new energy manager that allows less fluctuations of the quality of service between days and nights. Latency and energy are modeled in a hybrid manner, i.e., leveraging microbenchmarks on real hardware platforms, to explore the influence of the energy harvesting conditions on the quality of service of this heterogeneous network. It is clearly demonstrated that the cooperation of nodes within a cluster drastically reduces the latency of LoRa base station commands, e.g., by almost 90% compared to traditional LoRa scheme for a 10 nodes cluster.

【 授权许可】

Unknown