LoRa and multi-hop


We are deploying data loggers in remote locations, and we would like to use LoRa because it has better range (from what I've read). But in some deployments some nodes are too far away from the gateway (or not in line of sight), and can only reach it through other nodes.

There are many links, specially papers, about multi-hop LoRa.

But is it possible to do something like this in RIOT?

Thanks! David

Hello David,

RIOT doesn't have out of the box support for LoRaWAN relay nodes ("LoRaWAN multi-hop uplink extension" proposed in [1]).

However, it's indeed possible to implement such concepts in RIOT. GNRC LoRaWAN [2] could be a good starting point (several mechanisms from there can be reused in order to add a relay node).

Best regards. José

[1]: https://www.sciencedirect.com/science/article/pii/S1877050918304216 [2]: https://github.com/RIOT-OS/RIOT/tree/master/sys/net/gnrc/link_layer/lorawan

We found that Lora at 868MHz had about double the range through forest than the SAM R30 radio. So Lora would allow longer hops/wider coverage. However we need a "standard" lora hop/routing.

I am now becoming more interested in going back to testing the 170MHz range on a different transceiver - as that could provide lora-like range but with 6LoWPAN :wink: it would probably still be faster than lora too.

Meanwhile I need to sort out RPL on my test network :frowning:

Thanks for your answers. I think I'm going to first explore the RIOT network stack through 802.15.4, before eventually going back to LoRa.

Best, David

What hardware will you be testing with? we have had a nice experience with SAM R30 xpro boards (although they are quite expensive)

I have the Adafruit Feather M0 and a shield with the sx1276 chip. I believe I could use the 802.15.4 stack with this chip, using the FSK mode, but this is not supported by RIOT, https://github.com/RIOT-OS/RIOT/issues/11333

I also have the Zolertia Remote, this one has a CC1200 chip but RIOT doesn't have a driver for it, https://github.com/RIOT-OS/RIOT/pull/7598 At least I should be able to test the 802.15.4 stack with its other radio, at 2.4GHz but enough for trying out.

With the AT86RF215 radio I get 600m+ range in the city using the 868 MHz band in 6.25 kbit/s MR-O-QPSK mode.

This was the best I could get (which also mirrors [0] and the data sheet, which says that the MR-O-QPSK PHY is most sensitive on this device)

It's a 802.15.4g radio, so you can do standard 6LoWPAN/RPL.

Best, Benjamin

[0] https://hal.inria.fr/hal-01968648/document