LoRa: Ubiquitous connectivity for the IoT?

LoRa Alliance

LoRa Alliance

LoRa (as developed by the LoRa Alliance) 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.

As such LoRa is an instance of a family of communications systems called 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.

Similar to other LPWAN systems, LoRa targets deployments where end-devices have limited energy (for example, battery-powered), and where end-devices do not need to transmit more than a few bytes at a time. Contrary to some LPWAN systems, LoRa distinguishes itself by that 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)…

…so goes the story, in white papers, etc., as published by the organization (of, mostly, equipment manufacturers and vendors) behind the system, the LoRa Alliance.

Very intrigued by the promise of the technology (& the buzz of the marketing materials), but as the ever-sceptic academics we are, I, a couple of colleagues and students (this started as student research project in the elite “Advanced Communication Networks” master program by Ecole Polytechnique and Telecom-ParisTech)! set out to independently understand and quantify the actual characteristics of LoRa.

Lobby Art, Cisco France

Lobby Art, Cisco France

Our partners at Cisco France kindly provided us with an industrial router with a LoRa interface, patiently answered our technology questions (thank you, Patrick Grostete), and – most importantly – respected our requests to both not want any “insider information”, and to be able to publish whatever our findings, good and bad.

It is incredibly important when doing research with an industrial sponsor/partner, that they understand and respect the “academic independence”, and immensely gratifying when – as is the case with Cisco France – they respond with a “…but of course you can publish the truth” when making sure.

Field-testing LoRa

Field-testing LoRa

So, we did experiments. And analysis. And  more experiments. And some more analysis. And then we wrote up a paper, which was ultimately published early September.

LoRa MAC - very close to classic ALOHA

LoRa MAC – very close to classic ALOHA

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. And, some possible solutions for performancce enhancements are proposed.

img_0382We’ve got a couple of additional things up the sleeve regarding LoRa, so as they saying goes: “watch this space” for more exciting LoRa stuff in the future.

Meanwhile, you really should go read the paper.

2 Comments

  1. Gabor

    Hi guys,
    Very interesting in-depth analysis of LoRa. How about we have a more in-depth discussion on the Network Server side ? I work for Actiliy, the leader for LoRaWAN network servers.

    Gabor

    1. tclausen (Post author)

      Thanks, Gabor, for your interest and for the kind words.

      We would love to work with you/Actility on the server side – would you reach out to me at Thomas.clausen@polytechnique.edu?

      Best,

      Thomas

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