LoRa node and LoRaWAN gateway communication

Hello everyone,

I have done some experiment around with LoRa nodes and LoRaWAN gateway I have as mentioned below :

  1. WIFI LoRa 32 (V2) - Heltec Automation
  2. Dragino PG1302 LoRaWAN Concentrator.

Case 1 :
Used sandeepmistry LoRa (GitHub - sandeepmistry/arduino-LoRa: An Arduino library for sending and receiving data using LoRa radios.) library for node to node communication and it works well.

Case 2 :
Used LMIC-node (GitHub - lnlp/LMIC-node: LMIC-node | One example to rule them all. LMIC-node is an example LoRaWAN application for a node that can be used with The Things Network. It demonstrates how to send uplink messages, how to receive downlink messages, how to implement a downlink command and it provides useful status information. With LMIC-node it is easy to get a working node quickly up and running. LMIC-node supports many popular (LoRa) development boards out of the box. It uses the Arduino framework, the LMIC LoRaWAN library and PlatformIO.), for the node to gateway and TTN server communication. Everything also works good as expected.

My doubt is could I configure the gateway to receive the packets from the node using sandeepmistry LoRa library ?

I tried doing it, but gateway does not receive any packets on implementing above mentioned question.
But gateway being a LoRa receiver as well, should not it be also showing on the logs, that it received messages from lora nodes ? I believe it is something related to the format of the message it is transmitted.

Just a newbie in LoRa and LoRaWAN and I am trying it understand it as well as I could :slight_smile:
Any suggestions and help is much appreciated !!

First please explain why would you want to do that, that library is specifically a point to point LoRa library and not LoRaWAN as used by TTN ?

The point to point LoRa library will be using a different syncword to the LoRa library used for the nodes, so its expected that packets will be ignored.

My idea is to synchronize the hardware clock time between the 10 or more lora nodes.

As an idea I could implement it by using a lora node as master and others as slave, but if there is a collision at the master node, due to other nodes sending at the same time, it will create synchronization delay.

So I thought using a gateway is a better option which will act as master , and I can receive and send sync messages to multiple nodes at the same time. Later also I would also not send the messages to the TTN, but configure the gateway to send the synchronization message from the gateway itself, on receiving the message from lora nodes. Hence making my application a with multiple lora nodes to single gateway communication, where collisions would not be a factor.

So what is the TTN application that requires 10 or more nodes to be time synched ?

Are you really trying to modify the TTN Gateway software to operate as a normal LoRaWAN gateway and use on the side a point to point LoRa library at the same time ?

I think synchronization could be used at many places, but this is just an idea, because using LoRa to time sync sounds interesting. But it not a TTN application, also not trying to modify the TTN gateway software.

Trying to reframe my question,

If activate LoRaWAN gateway, and observe the logs, then should it show logs for a LoRa node, which is operating on point to point library ? But your point for sync word is good :slight_smile: , I have less idea about it, and would try to look into it. Maybe if, i set the same sync word, hopefully it should work.

Then its an out of scope topic for this TTN forum.

Thank you for your inputs.

Your ideas don’t appear to fit in the with general scheme of LoRaWAN which is about support 1,000’s of devices in an area for sensor data that is not time critical to much more than the nearest second.

It may be possible with considerable research to get a LoRaWAN gateway to log LoRa point to point, but, excuse the pun, I’m not sure what the point of that would be.

It is helpful for TTN applications.

Perhaps not a good idea to actually invite suggestions for this non-TTN topic ?

I would suggest that @megawine raise support questions for the sandeepmistry LoRa library either directly on that librairies Github page or in the Arduino forums.

You can’t. LoRaWAN gateways transmit or receive, not both at the same time. So you will still suffer from collisions.

What you want is not LoRaWAN so not subject for the TTN community forum.

@megawine You might want to look at the work done years ago on behalf of Deutche Bahn to synchronise their (e.g) platform clocks etc. - this was done within the limits of LoRaWAN and its associated specification and architecture though it may be at lower timing resolution than you are looking for. That was in scope for TTN and indeed was the subject of a couple of TTN Conf presentations and workshops - it may be these historic sessions (2018 or 19 IIRC) are viewable on the 'Net (GIYF/YouTube?) using LoRa and point to point implementations is not in scope as called out by others.

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