low power node without friendship

[Young]

Hi Support team,

nrf5 sdk for mesh 5.0,  nrf5 sdk 17.0.2, s132, SES;

We are trying to understand the LPN feature based on the LPN example because in our scenario there are a few node in the mesh network which will work under low power mode.   These low power nodes (such as switches) don't need to receive messages, so we really want to implement the solution without the friendship, without the friend nodes.

The low power node just works like this: the gpio interrupt wakes up the node and sends a message, and then go to sleep.  We have considered the iv update: in the life of the low power node, the sequence number cann't be wrapped since the number of the sent messages is not large enough. 

Is it possible to implement the solution like that mentioned above? And where should we change from the lpn example? 

If it cannot be implemented based on the LPN example, is there a nother approach making the node work under the low power mode (like the above description)? 

Thanks in advance!

[Young]

I learned about the low power mode from the LPN example, which is that except for the receive windown the scanner stays in the disabled state.  Is just diabling the scanner to make the device sleep and work under low power mode? Is there other places that should be taken care of ?

[Simonr]

Hi

I'm afraid the LPN node is only possible with friend nodes, as an LPN uses the friend node to be able to participate in the mesh network. You can have multiple LPNs befriending one Friend node though, if that helps. But how this works is that the LPN node wakes up periodically and polls the friend node for any new messages. The friend node then delivers any updates to the LPN. Here is more information on the LPNs in a Mesh network.

Best regards,

Simon

[Young]

Hi

In fact, in the real scenario, it is quite possible that all the friend nodes have been out of the mesh network for a little long time (greater than the poll timeout), however, according to the introduction about the Low Power node feature on this page , the LPN node will go to the high power option mode once the friendship terminates. For a battery based device, it absolutely cannot put up with this kind of situation.

We just want to implement a private local mesh network, not interact with other standard mesh network or nodes. How to make a battery based device take part in the mesh network? Is there a feasible approach for this kind of implementation? 

[Simonr]

Hi

The "this page" link only leads to this DevZone ticket, did you perhaps upload the wrong link? I would recommend having your battery powered nodes be LPN nodes, and then have stable friend nodes that forward data to them.

Best regards,

Simon

[Young]

Hi Simonr,

I have tested the LPN example (nRF5 SDK for Mesh 5.0), the current is around 5 or 6 uA and the onoff message can be sent well.  Now I want to make my project based on the LPN example for the low power device.  The low power device will only send messages, and will not receive any messages, so we will not implement the friendship for the low power devie, which means in our mesh network there are no friend nodes.  Is there anything needed to consider for our low power device project?