DATA LENGTH EXTENTION request rejected by master(app).

[fenil.patel]

          Hi , I am using nrf52832 and try to implement a high throughput in ble5.1. i interface memory with nrf52832 my task is to read the memory and send the data to the app with high speed. 

I set the MTU size to 247byte. i  send the array of 74 byte at a time using the "nus_data_send" function.

in this data of 74 bytes is fragment into 27-byte on-air packet. and it takes 15 milliseconds. to transmit 74byte.

I change on-air data packet length default(27 byte) to 80 byte using "nrf_ble_gatt_data_length_set(&m_gatt, BLE_CONN_HANDLE_INVALID, 80)"  function. but when i trace the packet using nrf sniffer client send the DLE request to master but the master send an unknown response. 

I don't know what's wrong. i use the wrong method or app that does not support the DLE.

if anyone knows the solution for high throughput then please tell me. 

Thank you.

[Amanda Hsieh]

Hi, 

From the sniff trace, the master doesn't support DLE as it responds to LL_UNKNOWN_RSP to nordic's LL_LENGTH_REQ.

Please see this post and this post. 

-Amanda H.

[fenil.patel]

Thank you for sharing information but i am using a device that has BLE 4.2 and android 9 version. but still, the issue is the same.

  

[fenil.patel]

so now what can i do? I have to work on the android side or anything else?

i am using only this nrf_ble_gatt_data_length_set(&m_gatt, BLE_CONN_HANDLE_INVALID, 80) function is this right method to DLE?

[Amanda Hsieh]

Hi, 

fenil.patel said:

so now what can i do? I have to work on the android side or anything else?

You can choose an android device which supports DLE. Please see this post. 

 

fenil.patel said:

i am using only this nrf_ble_gatt_data_length_set(&m_gatt, BLE_CONN_HANDLE_INVALID, 80) function is this right method to DLE?

Yes, to set a new data length, you could use nrf_ble_gatt_data_length_set. A new data length can be set for an existing connection or before a connection is established by passing BLE_CONN_HANDLE_INVALID to nrf_ble_gatt_data_length_set. 

-Amanda H.

[fenil.patel]

Thank you for reply 

But my problem not solve.

[Amanda Hsieh]

Hi,

As I explained in the previous, 
From the sniff trace, the master doesn't support DLE as it responds to LL_UNKNOWN_RSP to nordic's LL_LENGTH_REQ. 

Did you try other phones which support DLE? If you still have the problem, could you upload the sniff log with the new phone from starting the connection?

-Amanda H. 

[fenil.patel]

Thanks, i will try