Down here in South Africa where my colleagues and me deploy LoRaWAN sensors, we have periodic electricity outages of 2h30m at a time.
During these times it is very likely that the LoRa gateway goes offline.
Therefore we normally add a DC UPS to our gateways (Takealot).
In the most location we either depend on GSM/LTE or on long range WiFi networks. These internet services don’t always have backup power, and if they do these don’t always last through the whole power outage.
We started using RAK Wireless gateways because they have an “automatic data recovery” option. This feature allows the gateway to buffer all received packets and send them to the network server when the internet connection is restored.
Buffering packets on the gateway was possible on TTN V2 and while using the Semtech UDP packet forwarder. If one switch to Basic Station this feature does not exist.
On TTN V3 there is a long discussion about why buffering data on the gateway is bad. It can corrupt the MAC state. See this issue:
Normally there are two suggestions that are made to handle the scenario where network connectivity is lost:
- Buffer the data on the device, and send it to the network when a working connection is available.
- Add redundant coverage that uses different backhaul internet connectivity.
Both of these have their own problems.
- I as a user do not have access to add data buffering to the firmware of all the LoRaWAN devices I am using. Off the shelf there are very few devices that actually offer this feature. But even with this feature when buffered data is sent, one will break the network’s fair use policy.
- The areas we are working in barely have a single internet connection. There is no option to install a gateway on a redundant internet connection.
Looking at my dilemma - which does not seem to be far fetched - it looks like LoRaWAN is moving in a direction that only supports urban areas - places that already has other options for connectivity (Sigfox, NB-IoT). LoRa (long range) is ideal for connectivity in rural areas. But the limitations that are being introduced in LoRaWAN makes it very difficult to use there.
As an enduser I do not have contact with the LoRa Alliance. It would however be great to hear their recommendation on how to use LoRaWAN in the scenario with power outages as described above.
Does anyone have a reasonable alternative to buffering data on the gateway that can solve intermittent network outages?