nRF52840 Mesh Packet Dropout

[ramachandra]

Hi,

   We are developing the project based on nRF52840 chipset. We are configuring the chip for mesh application and using generic on/off model to send the data on the mesh. We are able to transmit and receive the data between multiple nRF52840 Device, But sometime the mesh packet dropout (ex out of 10 tries, couple of time its dropout) and will be received by the other device. Please let us know is there any way to resolve it so that the packet doesn't drop out and ensure it reaches to the other device without any loss.

How can we enable the reliable transmission in the mesh.

Regards,
Ram

[Didrik Rokhaug]

Hi, and sorry for the long wait.

At the moment, all our mesh experts are on vacation, but I'll do my best to help you until they are back.

Have you seen the documentation for reliable transmissions in the access layer?

https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.meshsdk.v4.2.0/group__ACCESS__RELIABLE.html

However, looking through the implementation of the generic on/off model, it looks like that is already used.

I am also a bit confused about one thing you wrote in your ticket:

 

But sometime the mesh packet dropout (ex out of 10 tries, couple of time its dropout) and will be received by the other device.

 Did you mean that the packet will not be received by the other device?

Best regards,

Didrik

[ramachandra]

Hi Didrik,

   We tried configuring the the option Publish transmission in the module app but it didn't Help us out, Still we see lot of packet loss. 

Could you please suggest the latest proxy mesh sdk APP (Where we can configure both Generic On OFF Server and Generic On Off client in single provisioning APP like below screen shot) which we can use and try it out if there is any improvement.  

Regards,

Ram

[Didrik Rokhaug]

Hi Ram,

Could you tell me a bit about your network topology?

How many nodes are there, how spread out are they (how many hops are necessary for a message to reach its destination), are there a lot of noise in the environment, etc.?

If the message passes through any relay nodes, you must also edit the 'Retransmit Count' and 'Retransmit Interval' in the 'Relay' section in the app. Or, you can set it in the source code directly: https://devzone.nordicsemi.com/f/nordic-q-a/33319/are-relay-messages-transmitted-more-than-once

Best regards,

Didrik

[ramachandra]

Hi DIdrik,

  Thanks for the reply, Please find the details below.

1. Could you tell me a bit about your network topology?

  We are using the proxy mesh SDK so that all the nodes in the  mesh network can be configured for both client as well as server.

2. How many nodes are there, how spread out are they (how many hops are necessary for a message to reach its destination), are there a lot of noise in the environment, etc.?

  The number of nodes in the network is not fixed, it varies on the use case how much distance the data need to be transferred ( Ex for covering 30 meter we use only 2 node, and to cover 50 meters we are using 3 nodes, similarly to cover  100 meters we are using around 6 nodes)

3. If the message passes through any relay nodes, you must also edit the 'Retransmit Count' and 'Retransmit Interval' in the 'Relay' section in the app. Or, you can set it in the source code directly:

   We tried configuring the retransmission count to more than 1 under the generic on off client model but it didn't help us out, even after configuring the retransmission count the packet are dropping out.

Also could you please elaborate on the below configuration why it is used.

1. The Proxy state:  When we set it ON, the node is not visible anymore in the nRF connect APP and even after power cycle the node doesn't appear anymore, Could you please let us know the usage of this setting

2. Difference between TTL Setting in Node configuration screen 1 and Publication setting screen 2

Screen 1

Screen 2

Regards,

Ram