What You Need to Know About Relay for LoRaWAN

We’ve heard a lot of common questions about Relay since it was recently announced. Here are the answers about what it is, and why it’s essential:

What is the Relay?
- It’s a range extender for LoRaWAN sensors and networks.
What are the benefits?
- Double your wireless range
- Reach distant sensors and locations
- Receive more transmissions
- Better sensor battery life
- Lower SF, better DR
- Improve your brand reputation
- Prevent premature gray hair
Is it a mesh network?
- No. Think of it more like a repeater. Meshes mean that each sensor on the network transports each other’s data. In this case, only the Relay transports data of other sensors, and only specific sensors, at that.
Why was it made?
- LoRaWAN has incredible range and penetration. Customers continue to find scenarios that push the limits of any wireless technology, including LoRaWAN. There have been many implementations that limit sensors’ ability to reach their gateways. These include physical and radio interference, and extreme distances. In many cases, adding additional gateways isn’t a feasible option (answered later in this article). Still, these sensors need to have coverage.
What’s the range?
- That’s a complicated answer, as it depends on the environmental factors of your installation. For example, if your sensor and Relay antennas are both underwater, your radio range is still zero. That being said…
  - It adds the additional range of a well-designed LoRaWAN radio. In an ideal scenario, your range is doubled, if not more.
  - The relay needs to see both the gateway and the sensor. If you have a lot of things in the way, that’s going to reduce the range, just like any other sensor.
What’s required to use a Relay?
- There are 3 components of Relay
  - LoRaWAN Network Server (LNS) that is running server-side Relay-compatible code
  - LoRaWAN Relay – Deviceroy Aria
  - LoRaWAN Sensor – sensors must be updated to run the LoRa Basics Modem version 4 (LBMv4) provided by Semtech
Where can I find the source code for LBMv4?
- Semtech has published it on Github: https://github.com/Lora-net/SWL2001
Which LoRaWAN classes are supported?
- Class A is supported by LBMv4 and the Relay
- Class B (with up to 4 multicast sessions) is supported by LBMv4. We’re evaluating it for the Relay since the Aria naturally supports Class B.
- Class C (with up to 4 multicast sessions) is supported by LBMv4. We’re evaluating it for the Relay since the Aria naturally supports Class C
Does the gateway need to be updated?
- No. Modern gateways support LoRaWAN 1.0.4 natively.
What’s the difference between LoRa Basics Modem and LoRa Basics Station?
- LoRa Basics Modem (LBMv4) runs on the sensor and Relay. LoRa Basics Station is a feature set that can run on gateways.
Do I need to run LoRa Basics Station on my gateway to use the Relay?
- No. LoRa Basics Station is not required to use the Relay.
Which countries/region profiles are supported?
- Here are the region profiles that are currently supported:
  - AS_923 (AS923-1, AS923-2, AS923-3, AS923-4)
  - AU_915
  - CN_470
  - CN_470_RP_1_0
  - EU_868
  - IN_865
  - KR_920
  - RU_864
  - US_915
What are some interesting use cases?
- Water/Gas meters and AMI
  - Gateways can’t be installed everywhere, which means that some meters are either out of physical range of the network, or restricted by interference within normal network coverage areas (basements, below ground, etc.). Relays can be easily placed to instantly add coverage, and at optimal physical angles for the sensors to communicate.
- Down-hole/sewer applications
  - When sensors are in pits, the only direction the signal can go is in the direction of open pipes and pathways. This usually means a signal that only goes straight up in a very tight angle. Putting a relay above this signal allows the sensor to have a new and horizontal broadcast in every direction, and for considerable distances.
- Oil wells
  - Oil environments are challenging. Oil wells are usually in remote locations where other radio signals can’t reach. A relay allows an affordable and dramatic range extension (miles) to reach an internet backhaul.
- Industrial/processing/refining facilities
  - Refineries are usually metal jungles that interfere with, and absorb, radio signals. LoRaWAN is the best performing radio, but even it can struggle in these environments. In these cases, signals typically don’t reach from the dangerous locations of the sensors to the gateways. Relays give them that reach.
- Hospitals, prisons, high-rises, complicated buildings
  - Some building types require high physical security, whether to protect bodies from radiation, or simply from each other. These scenarios include powerful barriers that limit the range of LoRaWAN. In tall buildings, reaching those extra floors without installing complicated networking is critical. Relays give range extension while also enabling signals to go around corners.
- Extending a network for general use without putting in additional gateways
  - Some installation sites cannot install more gateways, whether due to project costs, easement restrictions, unavailable power or installation locations, political red tape, or other reasons. Relays are small and self-contained to quickly and easily increase coverage.
Can the Relay decode the sensors’ payloads?
- No. It’s a repeater. It doesn’t have the encryption keys to read payloads.
How is the Relay powered?
- The Relay for LoRaWAN specification was written with the expectation that a Relay would usually be battery powered. This means that a lot of work has gone into power efficiency for both the Relay and the sensor. The Aria Relay is able to be powered by USB-C, PoE, battery, and solar+battery. In the event of a power loss, the Aria has an internal super-capacitor to give it a few days of emergency power while it alerts you that power is disconnected at that site. We recommend using the USB-C, PoE or solar methods for power, since those are indefinite power sources.
What are the cool features of LBMv4?
- We’re particularly fond of the following features:
  - Relay for LoRaWAN
  - Multi-region support in the same firmware file
Which LNS providers support Relay? We’ll keep this list up to date.
- Supported:
  - Actility (v7.3+)
  - Chirpstack (v4)
- In the works
  - AWS IoT Core for LoRaWAN
  - The Things Industry
  - Helium
  - NNN Co.
Is Deviceroy using the official LoRa Basics Modem, or is it proprietary?
- The Aria Relay is running the official LBMv4 stack from Semtech.
How many sensors are supported per relay?
- At this time, up to 16 sensors are supported per relay. Hopefully more soon. Contact the LoRa Alliance Relay Workgroup to add your voice to the request for more sensors per relay.
How do I limit which sensors are allowed to use the relay?
- You are able to designate the whitelist of sensors remotely through your LNS.
Does it replace gateways?
- Yes and no. A relay still requires a LoRaWAN gateway to connect to the internet and LNS. However, if you’ve been using additional gateways as range extenders for better coverage, you can use the relay for those purposes instead.
Why would I want to use a Relay instead of another gateway for range extending?
- Some scenarios are adequately suited for low-budget gateways to extend range. It’s uncommon and not recommended for enterprise use, but it’s certainly an option in some cases. However, Relay was designed with advantages over most gateways for range extending:
  - Gateways must be plugged in, which limits the possible locations of installation.
  - Outdoor-rated gateways are significantly more expensive than an outdoor-rated Aria Relay.
  - Most corporates won’t allow sensors and related data on their network
  - Gateways require a direct internet connection. This requires wires or a monthly data service fee, increasing costs.
  - Cellular-enabled gateways must be replaced when the cell modem network sunsets/retires.
  - Gateways have short-term warranties.
Can you hop relay to relay?
- Not at this time. That would be a very useful ability, but you’ll need to ask the LoRa Alliance Relay Workgroup if you’d like that ability added into the specification for Relay.
Which radios are currently supported?
- LR1110 with firmware 0x0308
- LR1120 with firmware 0x0102
- LR1121 with firmware 0x0102
- SX1261
- SX1262
What about the SX127x series?
- Great news! This radio series now has experimental code support for end-devices to use the LBMv4. Note that you won’t be able to run the relay itself with this radio. This was a great update from Semtech that enables companies with older end-devices to potentially update to use a Relay!
Is LBMv4 (relay support) available for modules, like ST Micro and Murata?
- Honestly, we don’t know yet. We recommend asking the module maker and Semtech. We’re asking around ourselves.
Will it work with any LoRaWAN network?
- Yes, provided that the network server (LNS) you select has been updated to support Relay functionality. You’ll need to check with them.
Will it work with private LoRaWAN networks?
- Yes, again, provided that the network server (LNS) you select has been updated to support Relay functionality.
Can I run a relay-compatible server locally on a gateway?
- We aren’t aware of any gateways that can do this yet.
Can I have more than one relay per gateway?
- Yes.
Is there a limit to how many relays I can run per gateway?
- We’re not aware of any intentional limitations. There are natural limitations based on how many sensors your gateway can support, the duty cycles involved, etc., but these are just normal factors of LoRaWAN in general to consider.
What’s the join experience like?
- For the relay: using our Nexus app, it’s incredibly fast. Pretty much the same as adding a normal sensor.
- For end-nodes: surprisingly close to the same as before. We recommend multi-RAN whenever possible, and if you have that, the change will be small.
How is it provisioned? Is it treated like an end-node?
- It uses the 3 normal keys: JoinEUI, DevEUI, and AppKey. This is done with our Nexus mobile app.
Do I have to use Deviceroy services?
- Aside from using the Nexus app to configure the Aria, you don’t have to use any Deviceroy service. In fact, with the currently supported LNSs, you’ll need to use a relay-compatible LNS.
Can I use Deviceroy’s services?
- Sure. You’ll still need a relay-compatible LNS.
Is there a monthly fee for using the Relay?
- No.
Is there a fee to use Deviceroy’s services?
- No. There’s no fee to use them, including visualizations.
Any surprises in the code?
- Yes, it’s a first version built on a very intelligent but theoretical tech specification. Some things can only be discovered by trying to build one. One of the surprises was the Join process in the US. The payload is inherently too large for the Join sequence in DR0. We are told that this is being addressed by Semtech and the LoRa Alliance. Our experience with Semtech is that they take these things seriously and work quickly to provide a quality resolution. In the meantime, we’ve implemented a couple of workarounds like starting with DR4 (in USA) and lingering on-air for a few minutes for ADR to take over and improve the data rate. Other regions don’t appear to be affected by this issue.
Anything else I should know?
- Yes, you’ll be moving from some runtime settings to compile-time settings, and vice versa. Some are nicely convenient; some may be a little frustrating.
- You have the potential to switch region profiles in runtime. That’s pretty cool.
Is it hard to do the firmware upgrade?
- Generally, no. It depends on how you created your stack and which LoRa codebase you’re using. We are pretty picky about intelligent and clean code, and we migrated from the LoRa-MAC-node codebase. We were already on LoRaWAN 1.0.4, so we had a few things in our favor already.
What was Deviceroy’s experience in doing the firmware upgrade?
- It took about two weeks of one of our developers to update our end-node to support the Relay. This was separate work from creating the Relay itself. It’s worth noting that Aria is a sophisticated device. Most sensors should update with less effort.
Can I contact Deviceroy for more help or tips along the way?
- Of course. Just remember that we didn’t write Semtech’s code, and that your Semtech FAE may be a better source of official information and assistance.
A standard Aria can do a lot more than just be a Relay. Can it be both a Relay and the end-node at the same time?
- Yes. If you would like both functions active, be sure to purchase the standard Aria rather than the Relay-only version.
My company uses other companies’ sensors. Can you work with them to help them update?
- Of course. We are happy to reach out and provide any assistance they need. Simply connect us with them and we can have the technical conversations with them, including hardware compatibility.
Can I put a different antenna on the Aria?
- We don’t recommend it. The FCC wouldn’t be pleased, and you probably won’t get the signal boost you’re hoping for. Aria was tuned specifically for the antenna it has, and it does a great job.
Can I use Relay with a LoRaWAN LEO Satellite service?
- The ability to relay several sensors to a space satellite is a very interesting project. We have test code and hardware in house to add this feature. It’s in the upcoming pipeline to integrate.
Can I put it outside?
- Yes. Note that the Aria itself is IP53. That’s not waterproof. If it’s going outdoors, be sure that it’s in an enclosure of another device, or you can purchase the battery or solar kits for the Aria. Both kits include an outdoor-rated enclosure.
What are the best practices for using the Relay?
- Follow the common sense of LoRaWAN in general. If it’s underwater, in a faraday cage, underground, etc., expect a less-than-ideal experience. We’re still constrained by the laws of physics.
Can I buy a cheaper Aria and change its firmware to run more expensive functions?
- No, but you contact Deviceroy Support to purchase a different firmware version. Each Aria knows which firmware it’s allowed to use.
How long is the Aria warranty?
- Lifetime. If it breaks, we’ll send you another one.
Will the Aria pass cybersecurity audits?
- Yes. We are a security-first company. We, and our devices, are compliant with the following standards:
How long do I get firmware updates for the Aria?
- For as long as we make the updates.
I’m a distributor. Can I become a reseller or distributor?
- Please contact Deviceroy Sales to discuss becoming a reseller/distributor.

Disclaimer: we are not Semtech nor the LoRa Alliance. Although Deviceroy is an active member of the LoRa Alliance and we like to think we’re good friends with Semtech, we’re speaking from our own experience and do not speak for Semtech nor the LoRa Alliance. Since we’ve made a relay, we know a thing or two. If you have more specific questions, you may benefit from directly contacting Semtech (they’re great!) or the LoRa Alliance. Any information on companies mentioned above is based on our best understanding at the time of this writing. Please let us know of any mistakes to correct.

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