Using LoRa without LoRaWAN
In my previous post I talked about what LoRa is, and how LoRa compares to other modulations. In this post, I’ll focus on what you can accomplish with “raw” LoRa compared to using the LoRaWAN protocol on top of LoRa.
Why should you listen to me?
See my previous post for details. TL;DR: My journey with LoRa started at IBM Research about 10 years ago (as of Nov 2023), where two of my former colleagues literally (co-)wrote the LoRaWAN standard — check the second page of the LoRaWAN 1.0.
Do I need LoRaWAN to use LoRa?
No, you don’t. But there are use-cases for which LoRaWAN is a great solution. It’s called a WAN for a reason. If you’re planning to use LoRa in a wide-area network, LoRaWAN is a good fit.
How wide is a WAN you ask? LoRaWAN was designed to run nation-wide networks, operated by companies similar to cellular network operators, or by actual cellular network operators. But it has seen great adoption in private networks where long range is of essence. The area covered in a private network is typically one site. I learned the hard way that a site can be a factory floor or an Australian farm the size of a small European country.
Is your use-case not a wide area network? It’s likely you don’t need LoRaWAN.
Where can LoRa stand on its own?
LoRa can be effectively used for peer-to-peer connections. In the early days, I remember people being excited to control quadcopters at great range over LoRa. They’d pack a set of joystick control values in each LoRa frame, without an actual protocol. And it worked!
LoRaWAN is a star topology network, but there’s nothing that prevents you from running a mesh network on top of LoRa if you need some extra range.
Although LoRa is mostly used on the ~900 MHz band, as long as regulations allow it, you can run it at any other frequency. And that’s exactly what some non-terrestrial networks ended up doing.
But that’s enough generalizing. Let’s dive into some of the concrete use-cases in which LoRa as a physical layer turned out to be a good fit.
Non-LoRaWAN protocols that use LoRa
Amazon Sidewalk
Did you know many of the Amazon Echo have a built-in LoRa radio? The network that runs on top of those radios is called Sidewalk. I wrote about it a long time ago, before more details were officially announced. Sidewalk has many similarities to LoRaWAN, but it is not LoRaWAN.
My guess about why they are not using LoRaWAN is the cost of gateway chips. The Echos are selling at a dime a dozen, so an SX130x would likely push the bill (and energy consumption) beyond what is commercially feasible.
Meshtastic
Did I say you could run a mesh network on top of LoRa? There’s actually a whole ecosystem around a LoRa-based mesh network called Meshtastic.
From what I know, it’s mainly used for communication in areas where there’s no cellular network coverage, in spots where it’s hard to reach anyone, for example in case of emergency. It’s powered by volunteers, so it can’t be compared with SLAs of non-terrestrial solutions, but it’s a great cost effective use-case of LoRa.
Link Labs
Link Labs has undergone a lot of transformation over the years. When I first met them in 2015, they were pioneering a US-specific MAC layer on top of LoRa that was not LoRaWAN.
The regulations in the US 915 MHz spectrum are very different from the regulations that govern the usage of the 868 MHz spectrum in Europe. If your product is solely focused on the US market, it’s likely you can run a MAC layer that is better tailored to the US regulations than LoRaWAN, just like Link Labs.
Drive-by smart metering
I did work on a drive-by smart metering use-cases where having to have a regular LoRaWAN gateway infrastructure turned out to be a no-go.
The goal was to replace a manual meter reading fleet of vehicles by collecting data over LoRaWAN. In the planning stage, it turned out that there just wasn’t a cost-effective way to deploy LoRaWAN gateways to get 100% coverage, and retire the drive-by fleet entirely.
So instead of LoRaWAN, the company ended up using LoRa to simply periodically broadcast the metered values. The drive-by fleet was reduced in size, and upgraded with a LoRa device that wirelessly collects the metering data.
[irony]I’m still waiting for this use case to be upgraded to autonomous drones flying around the neighborhoods, just to collect metering data.[end of irony]
Smart lighting
Street lighting has a particular challenge. Upgrading to smart lighting with LoRaWAN means you need a line-of-sight view to all devices, or reflections.
If you are upgrading a long street in dense urban area, you will eventually run out of line-of-sight range, and out of luck with reflections. Especially so if you deploy the gateway at street level.
Luckily, you don’t have to worry about running out of battery power. Ultimately, in the use-case I worked on it ended up being easier to deploy a broadcast/multicast capable mesh network that can hop LoRa frames from streetlight to streetlight, than to try placing gateways so that they would reliably cover all the lights.
One of the mesh nodes would then be acting as the gateway that connects the mesh to the management system.
2.4 GHz LoRa
You might have heard about LoRa on other frequencies than the popular sub-GHz bands. One of those is LoRa on 2.4 GHz, for which Semtech has a portfolio of chips readily available.
Given that there is no LoRaWAN specification for 2.4 GHz, you have to roll your own protocol no matter what. You could of course port the reusable parts of LoRaWAN to the 2.4 GHz physical layer (PHY).
Either way, the 2.4 GHz PHY is a different beast than its sub-GHz counterpart.
You could think of 2.4 GHz LoRa more like Bluetooth with some extra range, and little less bandwidth. After all, the 2.4 GHz LoRa chips have a Bluetooth compatible mode.
LoRa direct to satellite
The final non-LoRaWAN use-case I’ll mention is the direct-to-satellite path.
The challenge with satellites is that they hear a lot of chatter — their line-of-sight is literally out of this world. Not only that, but sending downlinks from space to a large device population is hard. It’s because targeting a single device with a narrow radio beam at that distance is a hard.
That means that while many non-terrestrial-networks (NTN) do have LoRaWAN compatibility (the frames will look like LoRaWAN), they might be focusing on the uplink direction (device-to-satellite) and might not be able to support all the downlink (satellite-to-device) features of LoRaWAN. So close enough to LoRaWAN, but not quite.
What is beyond the scope of LoRaWAN (and LoRa)?
You can’t stream video over LoRaWAN.
You shouldn’t really be streaming audio over LoRaWAN either.
And you shouldn’t be sending files - pigeons might be faster.
In general, any use-case that you would label as streaming is not a good fit for LoRaWAN. Think tens of bytes rather than kilobytes or megabytes.
What is beyond the scope of LoRa?
With LoRa (without LoRaWAN), you do have a lot more freedom. You still shouldn’t expect video streaming. But depending on the frequency band and the available channel bandwidth, you might have significantly higher data rates available than LoRaWAN has.
Therefore, I will not make a general statement about what is beyond the scope of LoRa. If you have a cool LoRa-based use case beyond what’s possible with LoRaWAN, please do share! I’m looking forward to learning about use cases where LoRa is pushed to the limits.
