BladeRF SDR register in TTN as end device

End Devices (Nodes)
1

Hello all,

I am exploring the possibility of reprogramming my BladeRF (SDR) to GNU Radio so that it converts the received signals (a sequence of numbers) into LoRa signals so that they can be received by my Dragino gateway. About my experience so far: Equipping the TTN with gateways, LoRa ESP32, LoRa sensors and LoRa GPS trackers worked successfully. These were all “LoRa devices”. Now I wonder how I have to integrate the BladeRF as an application in TTN. There is no JoinEUI or DevEUI here, as for example with the LoRa esp32, which was otherwise defined by the device. Can you please give me approaches how I can proceed here? Thanks in advance.

2

You will need to do two things:

  1. Get the SDR to chirp like it is a LoRa radio - whilst preventing Semtech lawyers from locking you in a deep dark cellar and extracting IP payments from your children’s children.

  2. Make those chirps have the format of the entire LoRaWAN stack depending on what data is being transmitted - and it HAS to be able to receive. You may want to read the LoRaWAN spec as this isn’t plain text RTTY, layers of encryption, nested header formats, timings, storage on the device, so much fun to be had.

Your lack of EUI’s comes from you not searching the forum for a well known popular EUI generator - but that’s the least of your challenges!

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3

Thanks for the quick feedback. Can you explain the danger from point 1 in more detail: I can insert regular from GNU Radio library LoRa blocks into my flowchart which make the BladeRF act as a sink with LoRa Tx, corresponding LoRa header, crc etc. And this fulfills a sending with LoRa specification to the gateway. Why is this against the law? Thanks for your help.

4

In terms of sensitivity, how close does the combination of BladeRF and GNU radio, when it generates a LoRa signal, get to the sensitivity of a typical dedicated LoRa RF device ?

And why use an SDR\GNU combination to transmit LoRa signals in the first place and of course what about the receive side ?

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5

Oh, and I forgot to ask;

Presumably you have the BladeRF GNU Radio combo working for point to point LoRa ?

6

I didn’t say that. I will infer that you are implying that you are inferring that I am implying that it is illegal under criminal law. I didn’t even suggest that it was illegal under civil law.

You may want to give some real serious consideration as to why the main GNU Radio wiki has no results when searching for LoRa.

There are indeed many plugins that do LoRa with an SDR with GNU Radio - but it’s not in the main repository and all the offerings are put in the context of being used for research purposes, not for replacing a few $$ worth of silicon that costs far less than any SDR but comes with an implied license for use of Semtech intellectual property.

Asking about an SDR implementation for research is one thing, but you said want to use it as a replacement for an actual device. Which is like phoning the police before you go out on a heavy drinking session in a country pub with the intention of driving home.

In these situations it’s not the right or wrong, it’s the weight of documentation that arrives in the post that you have to give to some one with the ability to draft a response that stops the follow up letters. That help is usually rather expensive.


Even if you try to reframe it for research purposes, the cat is out the bag now.

And if you can’t patch LMIC or LoRaMac-node over the top of the radio implementation, you are stuck with point 2 - which we would ask that you use a private LoRaWAN server for testing so as to not disrupt the TTN Community servers. There are only a limited number of people who will be able to help with questions on the internals you would need to implement.

To expand on this, this would only count if it was BladeRF GNU Radio to a LoRa device based on Semtech silicon.


Please don’t misunderstand, if you want to go on a voyage of discovery, great.

But if you just want to get some numbers from some unknown source that you haven’t specified, a sensor or serial or ModBus or whatever, there are many many many ways that can be implemented in a couple of hours this weekend with any of the Arduino based boards with a LoRaWAN stack.

Whereas writing your own stack will take some time. And potentially put you in a precarious position if you look to replicate it beyond your one “research” device.

7

All my research is supported internationally by a research group and presented at international workshops. I don’t think it has anything to do with “letting the cat out of the bag”. You are talking a bit past the topic of my actual question, but I thank you for the food for thought and will discuss the critical points about the use beyond a pure research purpose with my professor.

8

Given that you made no mention at all of you being a student or doing research, it wasn’t a totally unreasonable assumption that you’d be trying to use the system for live use. As for cats, I’m saying that trying to say that you are doing it for reasearch purposes is a bit late as it will just look like a cover up. Oh, wait, that’s exactly what you’ve done.

As a student, it’s a perfect fail to come and ask us for basic help when the learning materials & specifications are freely available online.

It’s even more of a perfect fail that your this is your third topic where you look to bend TTN to some unusual situation - it doesn’t provide an MQTT server for your use, you previously asked how a HackRF would fit in the mix with a gateway and now you want an EUI for a HackRF.

I would strongly suggest you learn LoRaWAN 101, the learn link is at the top of the page. If you need help dealing with your tutors or employer on how this is not a project for someone who’s not had extensive experience with LoRaWAN, get them to contact us on the forum.

But most of all, please do not use TTN for any testing - it has potentially disastrous consequences for the community around you.

9

Fair enough.

Absolutly key to your request for assitance from this forum for the possibility of using a Blade SDR GNU Radio combo on TTN is being open about how well the setup works at the basic LoRa level.

So, and its a really basic question, can a Blade SDR GNU Radio combo approach the sensitivy, or long range capability, of the standard sub $5 LoRa devices that use Semtechs devices ?

Its really a yes or no answer.

10

It’s not that impressive - I’ve answered software development issues for NASA and recently out-coded a PhD student working on Physically Unclonable Functions for device authentication.

Now if @kigehron’s research was on link budgets of commodity radio transceivers with a US university and subsequently went on to utilise that with a home-made PicoSat that actually went in to orbit and worked, I’d be impressed.

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