Range of Relay message is much shorter

[Vignesh R]

Hi,

I am using light_switch_client and light_switch_server in nrf5 mesh sdk to send and recieve custom messages which i have added to its default structure.

Iam able to recieve the data and able to relay the message to next server node,

but the max distance of client to server is upto 50 mts approx. and the max distance of the relayed packet from one server node to another server node is way less than 10 mts,

I tried creating a new fresh packet in server whenever it recieves data from client and tried publishing it manually to the next server node, it also covers upto 50 mts,

1.Do i need to change some configuration for relay packets to increase the distance covered?

2.Is there a way to check the route of the relayed packet in the end node(other than ttl of the packet)?

Thanks.

[Joakim Jakobsen]

Hi!

1)

max distance of the relayed packet from one server node to another server node is way less than 10 mts

This sounds strange.

Have you made any changes to the TX power settings or similar in the server/relay nodes?

2)

As BLE Mesh uses managed flooding for transmission, you can't really know which route the relayed messages takes. The message could be received at the destination multiple times depending on the available relay nodes in range. You could implement some solution in your application where the relay node add some information in the relayed message as to which route it takes.

Br
Joakim

[Vignesh R]

I have added phy_coded settings on both client and server according to this ((+) change phy in mesh - Nordic Q&A - Nordic DevZone - Nordic DevZone (nordicsemi.com)) ticket.

Tx_power is still 0dbm.

[Joakim Jakobsen]

Thanks!

Could be related to the implementation of coded_phy.

It could also be due to increased network traffic. You could try reducing the relay retransmit count (CONFIG_BT_MESH_RELAY_RETRANSMIT_COUNT) and see if there is some improvements.

Br,
Joakim

[Vignesh R]

Sorry for the delayed response,

Since i use only 3 nodes and 1 packet per 4 sec ,it couldn't be the network traffic,(without ack)

I have already set the retransmit count to disabled after provisioning via mesh app,

If this is related to the coded_phy implementation then how can i implement coded_phy also for the relayed packets? or is there any other solutions to this?

Thanks.

[Joakim Jakobsen]

No problem! 

Vignesh R said:

If this is related to the coded_phy implementation then how can i implement coded_phy also for the relayed packets?

The BLE Mesh specification is based on an older version of the BLE specification. That means that coded phy isn't really suppported and that is why we don't have any example implementation for it. 

Is it possible for you to manage without coded phy and maybe just increase the TX-power to increase the range a bit?

Br, 
Joakim