LR-FHSS in Network server

ChirpStack Network Server
1

Could anyone explain how LR-FHSS works in a Chirpstack server. What is the difference when it is enabled?
Is there anywhere to read more or does anyone have experience having tried it?

2

LR-FHSS is an alternative modulation to LoRa. Please note, both the device and gateway must be LR-FHSS capable. You need a v2 reference design gateway with FPGA and it must be configured (and updated) to support LR-FHSS.

Once ChirpStack receives a LR-FHSS modulated uplink, it will handle it for you. If you know that your devices and gateways support LR-FHSS you can decide to use a LR-FHSS ADR algorithm, either to select the best data-rate (which could be LoRa or LR-FHSS), or to force the device to always use LR-FHSS.

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3

Hi Orne,
Apologize for bringing back to life an old post.

Have you ever seen a Gateway that supports LR-FHSS?

Thank you for your support.

With best regards

Sebastian

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4

It seems LR-FHSS requires MCU from TI.
So far, I have not seen any commercial LR-FHSS gateways and nodes.

I am keen to know about them too.

5

For example, the Kerlink iBTS (which is a commercially available gateway) hardware supports LR-FHSS, but it requires additional software / firmware. But you are right that there aren’t many (if they exist at all) off-the-shelve end-devices that support LR-FHSS.

I did test LR-FHSS, but the software that I have been using is not publicly available. If you want to test LR-FHSS for your use-cases, the best would be to get in touch with Semtech.

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6

Hi @brocaar, I have the gateway and the firmware/software. But the LR-FHSS packets did not show up in Chirpstack Gateway live frames (Only legit LoRaWAN packets listed). Is it any addition setting I have to set/enable in the configuration? I am using lastest Chirpstack docker and leave everything to default (I am quite a newbie to Chirpstack). Could you help me on this? Thanks a lot!

Here are some additional information. I hope they could help for understanding the situation:

  • I am using EU868 frequency band
  • My end-device settings: freq=868000000, cr=2/3, bw=137kHz, grid=3.9kHz
  • Device profile is using MAC version 1.1.0, Regional parameters revision: RP002-1.0.3, ADR algorithm: LoRa & LR-FHSS ADR algorithm
  • The packet did show in the Gateway’s Packet Forwarder log
  • The Chirpstack log said: chirpstack::uplink: Deduplication error error=No channel found for frequency: 868000000, dr: 9.
  • I also tested with TTN community server. The packet did show up in the gateway live data but not in the application live data.
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7

This looks like a frequency issue, as in the default config that frequency is not used. Shouldn’t this be 868100000?

What the error means is that ChirpStack failed to map the frequency to a channel index (868.1 MHz -> 0, 868.3 -> 1, 868.5 -> 2, 867.1 -> 3, 867.3 -> 4, ....)

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8

Hi @brocaar, thank you so much for your responce! The Gateway supports LoRaWAN & LR-FHSS simultaneously. The uplink frequency you saw from my last post is default in Semtech configuration. I didn’t change anything.
FYI, I solved this by adding additional channels to my Chirpstack server. Just wonder why there is a difference between CR2/4 & CR2/6 of Chirpstack and CR1/2 & CR1/3 of others? They supposed to be the same, right?

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9

Yes, these are the same.

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10

Hi @brocaar, @cgt, We are currently setting up Chirpstack 4.7 to receive LoRaWAN messages via 4 Kerlink iBTS v2 for this balloon flight balloons/2024-04 · master · ThingSat / public · GitLab . We have the same problem. Could you provide us with the detailed configuration that you have implemented to solve this problem? Thank you

11

Hi @cgt and @brocaar we solved our issue thanks to the github of @cgt : Chirpstack-v4-LRFHSS-HTTPs/README-LR_FHSS.md at master · nguyenmanhthao996tn/Chirpstack-v4-LRFHSS-HTTPs · GitHub

Thank you !

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12

Hello. Any changes about commercially available gateways?
Seems that there are demo code exists for SX126x and LR11xx end nodes but looks like still nothing about gateways.
Even almost no any information about Kerlink iBTS Compact so not sure whether such gateway that i will buy will support LR-FHSS technology.

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