Beaconing and Low Power examples nRF5 SDK for mesh

[Thabet]

Hello,

I recently opened a ticket, with several questions about the mesh network, I had some evolutions and new questions emerged.

We have a firmware already consolidated for reading sensors using nRF 52840, these devices perform advertising that are read by a gateway. We use nRF5 SDK 17.0.2 on these devices, but we are looking to expand the number of devices and maybe the gateway signal will no longer reach all devices. Then came our interest in building a mesh network.

In order not to have to change the current firmware, we analyzed the possibility of creating a mesh network of repeaters, to allow the gateway to read information from devices that are not within its reach through the mesh network of repeaters.

How best to do this? It is possible to perform this mesh network through devices similar to the Beaconing example of the nRF5 SDK for mesh 5.0.0, so we would not change the firmware of the devices in the field at all, we would just put new devices "Beacons" to read the current devices and retransmit the advertising these devices through a network of "Beacons" to the gateway. Would it be possible? Currently I read the advertising of devices in the field through beaconing but I can't retransmit it through a mesh network, is it possible to do this by modifying the example?

Another possibility would be to modify the firmware of the devices in the field for devices similar to the Low Power Node example, so we would have to develop and insert "friendly" devices to build a network of friends, to take the advertising from the LPN devices to the gateway, right? So would we have to provision only the few friendly devices or would LPN also have to be provisioned? Do any of the examples have a demonstration of this type of application?

Thank you.

[Thabet]

Thabet said:

So would we have to provision only the few friendly devices or would LPN also have to be provisioned? Do any of the examples have a demonstration of this type of application?

I've already checked this by running the examples, and I realized that all devices have to be provisioned and not just friendly devices. I also verified that in this solution, despite being low power, the devices will consume more than in the current application, because they always have to look for friendly devices, and are sending data to these devices. In our current application we do not make any connection, the device is asleep and when it wakes up it changes its advertising and this is read by the gateway.

I accept suggestions, but perhaps the ideal would be to create a mesh network of beacons, capable of receiving advertisements from devices that are not within the gateway's range and transmitting these advertisements through the mesh network to the gateway. I still don't understand how I could do this, from what I've seen in the example beaconing, by default there is no advertising, only the advertisements of nearby devices are read and these are printed in the log within the rx_cb function, right?

I'm open to suggestions, but for what we've done so far, our main question is replicated below:

Thabet said:

we would just put new devices "Beacons" to read the current devices and retransmit the advertising these devices through a network of "Beacons" to the gateway. Would it be possible? Currently I read the advertising of devices in the field through beaconing but I can't retransmit it through a mesh network, is it possible to do this by modifying the example?

[Elfving]

Hey Gabriel! Sorry about the delayed response.

Thabet said:

I realized that all devices have to be provisioned and not just friendly devices. 

Yes, that is true. 

Thabet said:

the devices will consume more than in the current application, because they always have to look for friendly devices,

Well yes, they would look for a friend node until they find one. Then the radio use will be limited, which is what the friendship is for. Though I would imagine it might use more power than a device that does nothing besides advertising every now and then, as the LPN also needs to be updated with security keys, IV update, etc.

retransmit the advertising these devices through a network of "Beacons" to the gateway. Would it be possible?

Thabet said:

I accept suggestions, but perhaps the ideal would be to create a mesh network of beacons, capable of receiving advertisements from devices that are not within the gateway's range and transmitting these advertisements through the mesh network to the gateway.

I see where you are coming from when it comes to letting your devices be as they are and rather use some nodes to transmit the messages further through a network of relay nodes. This would be possible.

If you leave your devices as they are they wouldn't be able to send anything to the mesh network per se. You would have to use something like a gateway, for instance an EnOcean translator client, or such as you suggested: sending the BT messages so that they are being caught by the mesh nodes rx-cb. The mesh network needs mesh messages, but in the nRF5SDK for Mesh it can also get a callback from messages that aren't. 

I should also mention that mesh in general is not really a low power solution, as it is heavily dependent on relaying and constant radio use. At least one of your nodes should be connected to the power grid for it to pay off. 

Best regards,

Elfving

[Thabet]

Hello Elfving,

Thanks to your responses on this ticket and on another ticket which I've even closed and checked your response on, I see that the mesh network is not suitable for me, as all my devices are low-power. I came to the conclusion that I must implement a beacon, being able to read the advertising of devices that are outside the gateway's range, and retransmit these advertising with an increased tx signal, since this repeater beacon device does not need to be a low power device!

[Elfving]

Hey Gabriel!

Yeah, that could be a good idea :) I'm glad you found my responses helpful

Best regards,

Elfving