A Study of LoRa: Long Range & Low Power Networks for the Internet of Things

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5038744/

Abstract

LoRa is a long-range, low-power, low-bitrate, wireless telecommunications system, promoted as an infrastructure solution for the Internet of Things: end-devices use LoRa across a single wireless hop to communicate to gateway(s), connected to the Internet and which act as transparent bridges and relay messages between these end-devices and a central network server. This paper provides an overview of LoRa and an in-depth analysis of its functional components. The physical and data link layer performance is evaluated by field tests and simulations. Based on the analysis and evaluations, some possible solutions for performance enhancements are proposed.

Keywords: LoRa, Internet of Things, long range, low power

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1. Introduction

The essential difference between "the Internet" and "the Internet of Things" (IoT) [1] is that in the IoT, there is just "less of everything" available in a given device or network device: less memory, less processing power, less bandwidth, etc.; and of course, less available energy. This is either because "things" are battery driven and maximizing lifetime is a priority or because their number is expected to be massive (it is estimated that there will be 50 billion connected devices by 2020 [2]). This drive to "do more with less" leads to constraints that limit the applicability of traditional cellular networks, as well as of technologies, such as WiFi, due to energy and scalability requirements.

Another range of protocols and technologies has emerged to fulfill the communication requirements of the IoT: Low-Power Wide Area Networks (LPWAN). Colloquially speaking, an LPWAN is supposed to be to the IoT what WiFi was to consumer networking: offering radio coverage over a (very) large area by way of base stations and adapting transmission rates, transmission power, modulation, duty cycles, etc., such that end-devices incur a very low energy consumption due to their being connected.

LoRa (LoRa Alliance, https://lora-alliance.org) is one such LPWAN protocol and the subject of study for this paper. LoRa targets deployments where end-devices have limited energy (for example, battery-powered), where end-devices do not need to transmit more than a few bytes at a time [3] and where data traffic can be initiated either by the end-device (such as when the end-device is a sensor) or by an external entity wishing to communicate with the end-device (such as when the end-device is an actuator). The long-range and low-power nature of LoRa makes it an interesting candidate for smart sensing technology in civil infrastructures (such as health monitoring, smart metering, environment monitoring, etc.), as well as in industrial applications.