How to disable BLE retransmission and how to realize first listening and then adaptive frequency hopping

[Weng Zhuwei]

Hello

1. I want to disable the BLE retransmission mechanism on NRF52840, because this may cause a lot of latency in my application, how can I achieve this?
   
   
2. I see these two functions in the SDK17.0:

   ble_srv_is_notification_enabled 

   ble_srv_is_indication_enabled

   Can I disable retransmission through enabled notification?
3. I want to use SDK17.0 to realize the mechanism of first listening and then adaptive frequency hopping on NRF52840, can it be realized?

Looking forward to your reply！

Thanks a lot!

[ovrebekk]

Hi Weng

1. How do you experience this latency? 

There is no way to disable the link layer retransmission mechanism, this is always be active. 

If you send less data there should be less need for retransmissions, but otherwise there is little you can do. 

2. You can't disable retransmissions on specific characteristics no, but the client can chose to disable notifications or indications on specific characteristics to stop the data flow. This will reduce the need for retransmissions (but also stop incoming data, which might be a problem for your application). 

3. You mean you want to implement your own proprietary protocol instead of using Bluetooth?

Best regards
Torbjørn

[Mohsen Biglari]

Weng Zhuwei ovrebekk 

Hi All

Is it possible to read the number of retransmissions for each packet from the link layer?

Tanks in advance

[ovrebekk]

Hi 

Unfortunately the SoftDevice doesn't have any such feature. 

In the SoftDevice controller there is a mechanism called QoS Conn Event Report which allows you to get a report for every connection event which contains information about retransmits, but in order to use that you would have to use the nRF Connect SDK with the SoftDevice controller instead of the nRF5 SDK and SoftDevice. 

Best regards
Torbjørn

[Mohsen Biglari]

Dear ovrebekk 

Tanks a lot 

[ovrebekk]

You welcome