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BLE Scan Packet Receive Latency When Done Along Side Mesh.

Sivaguru Ravi

Hi,

Scenario:  Scanning  non mesh BLE packet with different stacks.

H/W Device -  nRF52DK

Observation:

Case 1. Non Mesh BLE Stack (Soft device):: Here able to receive scan packets in less than 1 sec interval.

Case 2. Mesh stack device                          : Here the scan packets are received around 10 to 15 secs of interval..

Is this expected behavior in mesh stack? Is there any way to decreases the latency between the reception of scan packets when done along with mesh?

Note: There is no difference in the advertisement frequency/packet in both the cases.

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  • 0

    Hi,

    I would like some more information regarding your solution and setup.

    What are the parameters for the advertisements being sent? Most importantly advertising interval.

    For Case 1, what application are you running and using what SDK and version? For instance, is it an example from the nRF5 SDK? Which one?

    For Case 2, I assume you are using an example from the nRF5 SDK for Mesh. Can you confirm? What example? Is it with or without GATT proxy feature? How do you scan for the advertisements? (Through setting up a scanner using the nRF5 SDK libraries or by hooking onto the mesh stack for getting the advertisements?)

    Regards,
    Terje

  • 0 in reply to tesc

    Case 1: SDK 15 ble_app_scan_c 

    Case 2: I have tried both integrating the scan in both proxy as well as non proxy server example of light switch. Both seems to give the same result.(nrf_mesh_sdk_2.1.1)

    I am scanning for the advertisements using the nRF5 SDK libraries (nrf_sdh libraries to be exact).

    As for the advertisement interval  it is set as small as possible. I am not able to tell the exact interval as the advertising device is an android phone and android ble sdk allows us to just set values like 1, 2, 3 levels.

  • 0 in reply to Anne van Rossum

    Hi,

    Sorry for the late reply, and thank you for the request!

    For you to change the mesh stack code is not a particularly good idea, as it would render the QDIDs void. (I.e. you need to qualify the modified mesh stack.) What that means in practice is that you will have to use the SoftDevice API for active scanning.

    I guess you could minimize the time spent outside of the mesh stack by only do active scanning for a short period of time, directly after having received a scannable advertisement through the mesh callback. (So that on the next advertisement you will get to scan.)

    Regards,
    Terje

  • 0 in reply to tesc

    Which QDID? https://launchstudio.bluetooth.com/ListingDetails/59560 QDID 111537 is limited to nRF5 MESH SDK 2.0.1. Anyway, it's not relevant for us.

    https://www.bluetooth.com/bluetooth-technology/topology-options/le-mesh/mesh-faq/

    Can I qualify my existing Bluetooth products with low-energy functionality for Bluetooth mesh?

    No, existing products cannot be qualified for Bluetooth mesh. However, those products may already have the inherent ability to be added onto a mesh network.

    Hence, we will not qualify them, but we will add the ability to function in a mesh. This means we can indeed make changes and provide a better customer experience in general. .

  • 0 in reply to Anne van Rossum

    Hi,

    Right. So it seems in that case you are good. For the record, nRF5 SDK for Mesh v3.1.0 is still covered by QDID 111537 which was filed for v2.0.1. I must admit I am a bit confused as to what constitutes a change requiring requalification, but my general recommendation is still to not touch the mesh stack if you can avoid it.

    I received an experimental patch (with support for active scanning) from one of our Mesh developers, but I see that you already got that a couple days ago in a separate (private) thread. I will leave you to that thread for now. When the issues discovered for that patch is solved then maybe we might share it here or in another public thread (as an unofficial patch, that is.) Unfortunately we do not have any immediate plans to merge that behavior into the nRF5 SDK for Mesh.

    Regards,
    Terje

  • 0 in reply to tesc

    Yes that is right.

    Sorry for the late replsy 

    Regards

    Sivaguru Ravi

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