Bluetooth mesh/time synchronization

RE: Bluetooth mesh/time synchronization

Hung Bui — Tue, 23 Jun 2020 08:50:25 GMT

Hi Tino,

There is something need to be clarified here. Bluetooth 5.0 protocol doesn't cover Bluetooth mesh. Bluetooth mesh is a independent protocol that only use the Link layer and MAC layer of the Bluetooth Low Energy. Speed of 2Mbps is only for Bluetooth Low Energy when in connection. Bluetooth Mesh doesn't do any connection and only use Advertising packets. Please read more about mesh network here: https://www.bluetooth.com/blog/introducing-bluetooth-mesh-networking/

RE: Bluetooth mesh/time synchronization

TinoMK — Tue, 23 Jun 2020 06:42:59 GMT

Hi Hung,

Thank you so much for your answers.

The throughput of the BT mesh you say it is ~3.5kbs. Why is this limitation when Bluetooth 5.0 protocol defines speed of up to 2Mbps. Can you please explain?

Thank you,

RE: Bluetooth mesh/time synchronization

Hung Bui — Mon, 22 Jun 2020 15:20:58 GMT

Hi Tino,

Time synchronization was not covered in current Bluetooth Mesh spec. Meaning for now you would need to do it proprietary way.

We have an example on time synchronization described here: https://devzone.nordicsemi.com/nordic/short-range-guides/b/bluetooth-low-energy/posts/wireless-timer-synchronization-among-nrf5-devices

The challenge would be how to define a timing master and how the time synchronization be propagandize in the mesh network.

The throughput for Bluetooth mesh is roughly about 3.5kbs, so it's not easy to achieve 1.5kB per second as your requirement.

Bluetooth Mesh is defined as a closed network, so there is no definition on how it should be connected to cloud and how it to be used with MQTT. It's up to you to define that. We have no gateway example that work with Bluetooth Mesh.