Yesterday we spent the day out in the car with the AIS NB-IoT device attached to my MacBook Air; looking at the serial monitor via USB and also recording messages back in the USA on my simple Python UDP server.
The bottom line is that this device is good for locating AIS cell towers
:wink: :wink: because it only worked when a tower with AIS NB-Iot support was visible (within line-of-site).
This means that this device seems to only work when it is very close to a cell tower and very close to direct line-of-site.
This also explains why this 900 MHz range device works on my sea-side balcony. There is a cell tower in our line-of-site on that balcony, only a few hundred meters away..
However, on the rear balcony, the AIS-NB-IoT device will not connect to the AIS network, and, as expected, there is no cell tower within line-of-site.
When driving around the countryside in Thailand, this device only "worked" when there was an AIS cell tower which supported NB-IoT in near direct line-of-site.
My best rough guess, driving from our condo next to the sea in Jomtien Beach to
Hardware House (picking up electrical supplies) in the country side, Rayong province and back (using two different routes), is that this AIS NB-IoT device connected successful to the AIS network approximately 70% of the time. This is just a rough guess because I was driving the car and my wife was looking at the computer, calling out the RSSI readouts and connection status. She really liked that part, I think!
Note to AIS Network Engineers: AIS NB-IoT device would not connect to AIS NB-IoT network at Hardware House in Rayong (or in that important area).
We experienced mixed results with the NB-IoT shield working as it went in and out of network coverage. Sometimes the device did not require a reboot to reconnect after losing the signal, sometimes it did require a reboot to reconnect.
To write code to properly mitigate this (connection management code), I would need the technical parameters from AIS for the network regarding connection timeouts (and other parameters) on their end; but since I only have the specification for the device (the BC95) and not the AIS NB-IoT network.
I have already reached out and sent an email to AIS for this basic timeout value.
Quote:
Dear AIS AIAP,
What is the timeout value for a connection to the AIS NB-IoT network from a device after a connection has been established and a message not received from the device?
Thanks!
Waiting on a reply ...
Soon, I think I will test LoRaWAN including LoRaWAN gateways and devices. More on this later.