Is it possible to use extended advertising for bluetooth mesh with a vendor model?

[NiLan]

Hi,

for a research project I would like to publish bleutooth mesh messages with a bigger payload (this would be our custom data). Currently we are looking at arround 70 bytes but it might be more in the future. These bytes should be inside one single message without segmentation.

After carefully reading the Mesh Specification I came across the following:

"The transport layer provides up to
11 octets for a non-segmented message, leaving up to 10 octets that are available for parameters when
using a 1-octet opcode, up to 9 octets available for parameters when using a 2-octet opcode, and up to 8
octets available for parameters when using a vendor-specific 3-octet opcode."

But with extended advertising I could have a payload of about 255 bytes per message (Bluetooth 5.0 - Source).

Is it possible to publish an unsegmented bleutooth mesh message with about 70 or more bytes using extended advertising?

 

I am using a Nordic nRF52840dk and an Adafruit Feather nRF52840 Sense, both with nRF Connect SDK.

Thanks in advance for answering!

Sincerely,

Niklas

[Hieu]

Hi Niklas,

The Bluetooth Mesh Profile v1.0.1 is based on Bluetooth Specification v4.2, where Extended Advertising isn't defined. Therefore, you cannot get the payload increase from using Extended Advertising.

Bluetooth Mesh Protocol v1.1 is released recently. However, to my understanding, Extended Advertising packet types is not supported in it either.
Update*: I checked the v1.1 spec, and section 3.3.1, Advertising bearer, still specified ADV_NONCONN_IND as the only possible advertising packet type.
(This section is at the same number, 3.3.1, in spec v1.0 for anyone interested).

In NCS, you might find CONFIG_BT_MESH_ADV_EXT. Please note that while it says Extended Advertising is used, it is used for other factors of advertising, not packet type and size.

Due to the above, unfortunately, an unsegmented 70-byte long Bluetooth Mesh message is not possible.

Hieu