Dear all
Together with some colleagues, I am developing a platform for LoRaWAN connected CO2 sensors in Berlin (we will give a short presentation on the upcoming TTN community meeting). In our tests so far, we had quite mixed experiences with network performance and reliability. Therefore, I am interested with operational experiences from other projects in the Berlin area. In particular:
- How stable is the coverage in which areas of the city? How many of the GW available are pretty stable, how many come and go (e.g., being taken down by their owner or switched off temporarily)?
- How does indoor coverage compare to outdoor coverage?
- What is the network utilization? Are GWs regularly dropping packets? are there too many nodes for too little airtime? Or is there airtime and backhaul capacity to spare?
- What is the operational experience with the network infrastructure? To me, TTN appears to be a black box. Do you have insight on stability of the platform, its capacity and performance? Are we stretching the resources or can it handle many more nodes?
- Which projects are there that have operational nodes all over the city? Is there some publicly available information on these projects? Or even persons involved who would like to share some experiences on what to expect in terms of coverage and stability?
- I read here on the forum about several industry partners who are putting up GWs. Yet, most of the discussion centered on research projects. Does any company or public institution have plans to provide additional GWs? What about the public sector?
With all these questions, I am basically trying to get a picture on how reliable TTN in Berlin is and will be. If small businesses are to invest in networked air quality sensors, they want to know up front if the sensor will be able to connect at a decent data rate or if it will remain useless at their location.
As mentioned, our experience has been rather mixed:
- A custom-built node (AdaFruit Feather LoRa, a simple wire antenna and our own software atop the LMIC library) is doing quite well. Commercial nodes at the exact same location are doing much worse, (SF12 vs. SF9).
- Downlinks seem to be a problem throughout: Joins often take forever, even in spots with good coverage. ADR messages often do not seem to get through. This is irrespective of the device and the location.
- We see quite some unexplainable message losses, sometimes for several hours. Like if someone switched off their GW for a night, or if queues in the TTN stack started dropping packets.
- In the outskirts between central Berlin and Potsdam, we had a hard time connecting nodes to the network at all.
I am rather new to the community. So maybe some of the questions above have been asked before, maybe there are resources I don’t know about yet. Then I would be happy to learn about them. Otherwise, maybe the discussion here can be helpful for others in the community as well.
Thanks a lot for your insights!
Uli