Testing the BLE_DataThroughput application

I'm trying to check the dependence of BLE data rate with respect to distance from the board. I runned the BLE_DataThroughput example but I'm having a hard time to interpret the info on the gatt_server terminal (I'm using a nucleo board with a smartphone).

1) here I sent the word hello

** data error ** N= 4 
DataThroughput = 5 bytes/s lost = 116762973 

what does lost = 116762973 mean?

2) I expected to see a roughly constant value of bytes/s (and higher of course) but it seems that the software just counts out the amount of characters that I send from the smartphone.

DataThroughput = 22 bytes/s lost = 0 
DataThroughput = 70 bytes/s lost = 0 

in this case https://community.st.com/s/question/0D53W00000ElwrQSAR/stm32wb-data-throughput-issues someone got higher throughputs.

How to understand this behavior? Thanks in advance.

[Remy ISSALYS]

Hello,

In BLE_DataThroughput application when it's configured as GATT server, the application checks a sequence number into the payload that received in the write packet and if this number doesn't follow the previous, the number of lost packets is incremented. You can use the example without any modification and use ST BLE Toolbox application on the smartphone and check the throughput in the log.

Best Regards

Thanks for explaining. What about the 2) question?

[Remy ISSALYS]

Hello,

The data throughput value depends on data send by the smartphone, if the smartphone sends only few data, the throughput will be very low. Try with ST BLE Toolbox application in upload window and you will see higher throughput.

Best Regards