Which mesh (Zigbee, Thread, Bluetooth Mesh) network protocol for unusual use case?

Question

I’m creating an IOT device with some unusual needs when compared with typical home automation. I wanted to ask if anyone knew of a mesh protocol (Zigbee, Thread, BLE Mesh), that might be able to achieve this user experience:

1. When someone turns on their device, it looks to connect to a mesh network, comprised of other devices they have previously “friended”.
2. If no network is found, it creates its own mesh network, available for other “friended” devices to connect to, when those devices turn on.
3. If the device creates its own mesh network (as in behaviour above), but no one connects to it – and then the device finds a different network with more than one friend on it, the device should kill its own network in favour of connecting to the other.
4. I’m expecting that there will not be a “master” node who has “friended” every possible device that wants to join the network – I’d like the possibility for “friends” to bring their “friends”, to also join the network.
5. If a partition in the network occurs (this is very likely to occur in my use case), the network should automatically re-form when the devices are close to each other again.
6. All devices are expected to be identical in function, size, software – so BLE Mesh is probably not suitable given it needs a “Provisioner”?
7. Messages transferred will be bespoke to this application – ruling out Zigbee’s Application Layer?
8. Messages will be small in size, so data transfer speed is not a big concern.

I believe from what I’ve read that Thread is probably the most suitable for this use case – but wanted some other opinions to see what the best choice might be? Seems to be a bit of a mine field to fully understand the ins and outs of all of these mesh protocols!

Answer 1

I believe Thread/OpenThread addresses all of the use case items you listed above.