Mesh Network based on BLE4.0

[Hongtao]

Hi All,

I noticed CSR has just released something called CSR mesh, please see: http://www.csr.com/news/pr/2014/csr-mesh, and a demo video: http://www.youtube.com/watch?v=FtLBazKoFq8&feature=youtu.be, It is very attractive, and it was said based on BLE4.0, Does anyone have any ideas on how it is implemented? will Nordic chip do this?

Thanks.

[ovrebekk]

Hi

Thanks for the link, that video is pretty cool :)

If I were to guess I would think that the nodes in the demo are combined observers/broadcasters. Each node will be listening for advertise packets continuously, and when a new packet is received the node will start advertising the same data for a certain amount of time to act as a relay in the system. In this situation the phone would either have to act as an advertiser (currently not supported on Android), or it would have to establish a direct link with one of the nodes, to get access to the system.

The big question is what kind of power consumption you will get with this kind of system. The drawback of being an observer is that you need to turn on the receiver continuously, which increases the average current consumption.

The nRF51 platform can definitely support similar protocols, even though we don't currently provide a stack that does concurrent observer/broadcaster. In less than a month we will have an API allowing you to get full control over the radio in between BLE events. With this solution I can imagine two different ways that you could implement something akin to the CSR demo:

1. Use the S110 stack and BLE for the phone connectivity only, and implement the node-to-node mesh network using either a proprietary RF protocol or ANT.

2. Use the S110 stack for the advertiser and peripheral, and implement the observer role in the application space. Since the observer only has to read and decode advertise packets this is something that can be done fairly easily.

Later we will also have a stack doing concurrent broadcaster/observer, but as mentioned above you don't really need that.

Best regards Torbjørn

[Hongtao]

Hi Torbjørn,

Thanks for your detailed reply, I am looking forward to Nordic's official implementation.

if the application is lighting control / smart home, power consumption is not a problem. if BLE can work in mesh mode, it will kill ZIgBee.

There will be some topics on Mesh Network with BLE in the Bluetooth World 2014, It seems this is a good direction.

[Anne van Rossum]

Is the idea of the nRF51422 with the S310 not to do exactly this?

Use BLE to have a phone connect to the network.

Use ANT for a mesh.

Or am I wrong?

[ovrebekk]

While ANT allows mesh networks it isn't the main use case for ANT in my experience. I believe most ANT applications use star topologies only.

That said, I agree the S310 ANT/BLE stack should be a possible option to implement something similar to the CSR demo. Rather than using advertising and scanning in BLE you could set up broadcasting channels using ANT. A big advantage of this approach is that the S310 stack is available today, while we don't currently support combined advertisers/observers.

[David Edwin]

There is a sample mesh protocol available on the nRF51 at https://github.com/NordicSemiconductor/nRF51-ble-bcast-mesh , this can be used to enhance your understanding of the mesh with BTLE. Feel free to contribute and comment. This is not part of the official Nordicsemi SDK.