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CC2651R3: Observing intermediate advertising packets with 2x set advertisement interval

Ddnr
Expert 1760 points
Part Number: CC2651R3

Hi Ti,

We use CC2651R3 chipsent with Ble sdk version 6.20 in our project.

During the advertisement tests, we observed that there are some advertisement packets with advertisement interval different to that of already configured advertisement interval according to our requirement.

More specifically, if we have configured advertisement interval as 200ms, then we observe ~83 number of 400ms packets (in an advertisement duration of 10mins).

In 10mins = 600s, there we expect around 3000 packets with 200ms advertisement interval, of which 83 numbers are 400ms packets (constituting ~3% of overall packets).

This also means 83 advertisement packets are lost (with 200ms advertisement interval) ?

Please find the attached log for more details regarding this behaviour.

2secondspacket.xlsx

We observed similar situation in the simple peripheral example source, ie 36 packets out of total advertisement packets (already advertisement interval configured to 1second) are 2seconds packets.

Also with the previous SDKs also the similar situation is observed.

Please let me know the reason behind this observation, and is this expected?

Thank you.

  • 0
    TI__Mastermind 42320 points

    Hi.

    Thank you for reaching out. We will look into your question and get back to you as soon as possible. In the meantime, could you specify which project you are using for your testing?

    Best Regards,

    Jan

  • 0 in reply to Jan
    TI__Expert 5150 points

    Hi,

    I advise you to update your SDK with the latest version.

    I'm curious about your test, how did you count the packets?

    Also, it's normal to loose advertisement packets for a device, that's also why we replicate data in 3 different channels. In my experience, I consider that 3% is not that big.

    According to your thread, the advertisement interval is not directly impacted, as when you lost a packet the next one appears after two advertising intervals (400ms).

    regards,

  • 0 in reply to Jan
    Expert 1760 points

    Hi Jan,

    Ddnr said:
    We observed similar situation in the simple peripheral example source, ie 36 packets out of total advertisement packets (already advertisement interval configured to 1second) are 2seconds packets.

    As I mentioned above it is the simple_peripheral example for CC2651R3 chipset.

  • 0 in reply to Guillaume
    Expert 1760 points

    Hi Guillaume,

    We are using latest SDK. With previous SDKs also we observed this behavior.

    We use Wireshark tool to capture the advertisement packets and filter based on the advertisement interval. (please find the attached .xlsx for the same, marked in RED are the packets with 2s advertisement interval)

  • 0 in reply to Ddnr
    TI__Expert 5150 points

    Hi,

    To be on the same page your SDK version is 7.10.00.98 right? (it's the latest one).

    Did you make your test in your office environment?

    What are all the activities of the radio? Does the device is only advertising? Scanning? Connected to a device?

    regards,

  • 0 in reply to Guillaume
    Expert 1760 points

    By mistake I mentioned we use latest version. We use ver6.20 SDK. Also as I mentioned we observed this behavior in previous SDKs as well. I can test using the 7.10 version of SDK and let you know the results.

    Guillaume said:
    Did you make your test in your office environment?

    Yes, test conducted in the office environment.

    Guillaume said:
    What are all the activities of the radio? Does the device is only advertising? Scanning? Connected to a device?

    The device is only sending out connectable advertisement and not connected.

  • 0 in reply to Ddnr
    TI__Expert 5150 points

    I cannot ensure you that the latest SDK will fix it, but we could try. 

    Also in my experience having 3% of lost advertisement packets in your environment is totally expected. 

    Let me know when you have tested with the latest SDK.

    regards,

  • 0 in reply to Guillaume
    Expert 1760 points

    Hi Guillaume,

    Thanks for the info.

    But I would like to know the reason how this advertisement packets loss happen?

    And how can it be reduced ?

  • 0 in reply to Ddnr
    TI__Expert 5150 points

    Hi,

    It could be a lot of different things, I mentioned your environment but there is also the quality of your scanning device.

    Try to make some tests in a shield room (anechoic chamber) you should have less advertisement packets loss.

    Regards,