number of the tranmitted packets of BLE PER

RE: number of the tranmitted packets of BLE PER

Hieu — Fri, 02 Dec 2022 13:07:19 GMT

Hi damienking,

The 0.625ms interval between packets comes from the Bluetooth specs for DTM.

ceil((L + 249)/625) should be calculated to 1 in our setup, and thus the interval should be 0.625 ms. I need to double check more in the code or with a different engineer to confirm this.

Assuming the 0.625ms number is correct, 1180/1600 is horrible. I am not too familiar with DTM, much less the Python approach in nAN 34, so please help with a few questions:

- Are you sure the test is 1 second? Is it designed that way in the Python application?

- Can you repeat the test with the Test with another development kit or the Testing with nRF Connect for Desktop option?

Hieu

RE: number of the tranmitted packets of BLE PER

damienking — Wed, 30 Nov 2022 22:49:37 GMT

Hi Hieu:

thanks for your help.

yes, i am using the DTM sample & Testing with nRF Connect for Desktop.

and now i trying to use the python example from nan34 ( dtm.py) not dtm.c

https://infocenter.nordicsemi.com/index.jsp?topic=%2Fstruct_appnotes%2Fstruct%2Fappnotes_nan34.html

in dtm.py:

it used (total running time)/(calculateTimeForPackage) as the total transmitted packet,

and calculateTimeForPackage is 0.625ms, how does this 0.625 been calculated?

why it's 0.625ms?

i have tried test PER with conducted connection between 2 nrf52840 Kit,

so this means the lost packet should be very little,

and the 2nd nRf52840 kit Rx got around 1180 packets per second in this test setup.

according to the dtm.py, total packet per second should be 1/0.625ms= 1600 packets.

python code of dtm.py:

def _calculateTimeForPackage (self):

"""Calculate how long time from start of one package to the start of next"""

return 0.625

def _calculatePER(self, receivedPackages):

"""Calculates the PER"""

maxpackages = int (round(self.runtimeinms / self._calculateTimeForPackage ()))

lostpackages = maxpackages - receivedPackages

lostpackages = max(0, lostpackages)

self._debug("Received: %s Max: %s Lost: %s" % (receivedPackages, maxpackages, lostpackages))

per = int (round((float(lostpackages) / float(maxpackages)) * 100))

return per

thank you!

RE: number of the tranmitted packets of BLE PER

Hieu — Thu, 24 Nov 2022 22:06:05 GMT

Hi damienking,

I found something yesterday.

You can find in dtm.c the function on_radio_end_event(). It is used to handle NRF_RADIO_EVENT_END event. Currently the function is implemented to only count RX packets. But you can expand it to count TX packets as well.

From my understanding, the "number_of_packers" you see is the RX packet count, and that is sent in on_test_end_cmd(). You will also need to look into how to expand that function to report TX packet count as well.

This answer is assuming you use the DTM sample. Please let me know if you are using a different setup.

I hope all of that helps.

Again, as I am out of office Thursday and Friday. Don't hesitate to reply if you need further support, and I will follow-up on those when I get back to office.

If you need it urgently, please let me know and we could arrange an alternative.

Hieu

RE: number of the tranmitted packets of BLE PER

Hieu — Wed, 23 Nov 2022 16:38:41 GMT

Hi damienking,

My apology for returning later than I said I would.

I was able to learn and understand a little about DTM and the structure of the DTM sample now.

However, I now see that the packet transmit is done by PPI instead of a timer handler, I am not sure how we can get be informed of the TX event to do the counting.
Replacing the PPI setup with a handler setup might be a problem since the timer period is 625 us, very short.

I will ask our internal team about this. As I am out of office Thursday and Friday, I will follow up with you latest by Tue 29 Nov.

If you need it urgently, please let me know and we could arrange an alternative.

Hieu

RE: number of the tranmitted packets of BLE PER

Hieu — Fri, 18 Nov 2022 19:53:27 GMT

Hi damienking,

Just want to let you know I am assigned to this ticket. This part of BLE is one I am unfamiliar with. I will need some time to look into it. I will get back to you latest by the end of Tue 22 Nov

RE: number of the tranmitted packets of BLE PER

damienking — Fri, 18 Nov 2022 04:20:53 GMT

i just find out that number_of_packers will always be 0x0000 for tranmitter test, so we have to count the total transmitted packet on our own.

any advice for counting the packet for different BLE format? thanks