WL1831MOD: Transition from BLE 4 to 5

Hi Bernd,

I will follow up later today or tomorrow.

Best,
Jacob

Hi Bernd,

Our WL1837MOD is 5.1 compliant, but is not fully certified to BT 5.1. This means that we do not support the optional features for BT 5.1. Our last certification was for BT 4.2. 

I would expect that you see an HCI version of 4.2, but I can test this and update the post.

Best,
Jacob

Hi Jacob,

this is bad news.

Customer has high pressure on this topic because they have some end customers requiring using BLE (for iOS compatibility) and with version 4.2, they are not able to reach the expect data transfer rate.

What do you recommend?

Regards,
Bernd

Hi Bernd,

BO said:

expect data transfer rate

Are you able to share the data rate they expect? Do you know if this is a mandatory or optional feature for BT/BLE 5.1? Our device is 5.1 compliant, so there is a good chance it does support this data transfer rate if it is a mandatory Bluetooth feature. You can check the Bluetooth SIG listing for WL1831MOD here. 

Best,
Jacob

Hi Jacob,

see comment: Using a PC and an iPhone we can reach something like 23Kbytes/s.
We would like to be close to that level using our device with the WL1831MOD.
We have succeeded to upgrade to BLE 5.1 but we haven’t noticed any improvement on the data-rate front.
The UART we are using to address the WL1831MOD is running at 921600 bauds, so that should not be the bottleneck.

Regards,
Bernd

Hi Bernd,

BO said:

see comment: Using a PC and an iPhone we can reach something like 23Kbytes/s

Is this data being sent over BLE? Are you taking about the GATT profile? If so, there are a few factors that can determine BLE data transfer rate, such as the PHY, ATT MTU, connection interval, etc.

Best,
Jacob  

Hi Jacob,

see customer comment:

Sorry for the delayed update on this topic.

I was waiting on my colleague to provide you more insights.

Yes, we are transferring data over BLE, using a service with 2 characteristics (https://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.5.1/nrf/include/bluetooth/services/nus.html

 About the PHY, ATT MTU and connection interval, honestly, I have no clue. I assume this is negotiated at connection time and depends on the device which is connected to the WL1831, isn’t it ?

Regards,
Bernd

Hi Bernd,

Can you ask the customer how they are measuring the data rate? 

From what I can tell, the customer is running BlueZ on the WL1831MOD and nRF Connect on the iPhone. Is this correct? To improve data rate, I would recommend trying to increase the ATT MTU size. The customer is right that the two devices will negotiate the MTU size and use the max supported on both devices. I believe you can change the ATT MTU size with gattool.

Thanks,
Jacob