Throughput BLE Meshv4 nRF52840

[PaulGui]

Hi community !
I saw a lot of subject about "Mesh throughput" which was outdated and i still have questions.
I'm using nRF52840 DK with nRF5 SDK for Mesh v4.0.0

1) Does Bluetooth Mesh still based on Bluetooth v4.0 ?

2) I saw that max 11 byte payload could fit in one message, is it still the same for mesh v4 ?

3) in file radio_config.c (from project : ble_app_uart_coexist_GATT ), we can see :
" #define RADIO_CONFIG_ADV_MAX_PAYLOAD_SIZE 37" line 53

"#define RADIO_MAX_PACKET_LEN          258" line 67

Do those lines correspond to message max length and max payload for mesh ?

4) Have you test max throughput with nRF52840 and SDK Mesh v4 ? if yes, could you give me result to compare with mine (future test)?

Thanks
Sincerely
PG

[Hung Bui]

1) Yes, it's mainly based on Bluetooth 4.0 however some Bluetooth 4.2 feature (Long ATT MTU) is supported on the GATT bearer connection but it doesn't related to the mesh performance. 

2) Correct. Larger payload will be transmitted on segmented packets.

3) It's the payload of the advertising packet (37). It's not the payload of mesh packet.

 RADIO_MAX_PACKET_LEN  is the radio hardware max payload. 

4) In our test here the mesh throughput is roughly 3.45kbps point to point. 

[PaulGui]

Thanks for your quick reply !
Just to be sure, Mesh messages have 31 bytes payloads but only 11 bytes for real information (string etc) ?
And your "3.45kbps point to point" is throughput for the entire message or only the 11 bytes of info ?
Sincerely

[Hung Bui]

Correct, 31 bytes payload for the advertising packet (37 bytes with the overhead) and 11 byte for actual mesh data. 

The 3.45 kbps throughput is calculated on the 11 bytes of of actual payload. 

[PaulGui]

Thanks for your reply !
Do you have practice throughput of classic BLE (p2p) on advertising and connected pls ?

Cause i want to compare throughput between Classic BLE (p2p) and Ble Mesh to know if it's better to implement Ble Mesh when sensor model will be out.
Even if i'm expecting a huge gap between BLE and BLE Mesh
Sincerely

[Hung Bui]

Yes, connected BLE has the theoretical through put of 1.4Mbps (when running at 2Mbps) and 700kbps (when running at 1Mbps) . I have seen the practical throughput close to these number (~1.3Mbps and ~600kbps). 

[PaulGui]

Thanks again !
For info, do you have an idea when sensor model will be out ? Or if an actual model could send logs ?