BLE Scan Packet Receive Latency When Done Along Side Mesh.

RE: BLE Scan Packet Receive Latency When Done Along Side Mesh.

tesc — Mon, 14 Oct 2019 11:05:35 GMT

Hi,

Thanks for the clarification.

Not publicly shared yet, no. May find its way into a release eventually, but still lacks testing and from what I understand some code cleanup. Other tasks has been prioritized over this one, I am afraid.

So, nothing official yet.

Regards,
Terje

RE: BLE Scan Packet Receive Latency When Done Along Side Mesh.

Anne van Rossum — Mon, 14 Oct 2019 10:47:06 GMT

Hi Terje,

* Did you find time to share it publicly as an unofficial patch.

* Although you didn't have immediate plans to merge it into the nRF5 SDK for mesh, things might change. You might decide to have official active scan support after all. Hence, my question. Has this (active scanning) already been made official? :-)

Kind regards,

Anne

RE: BLE Scan Packet Receive Latency When Done Along Side Mesh.

tesc — Mon, 14 Oct 2019 09:29:17 GMT

Hi,

Sorry, I am a bit confused as to what you refer to by "it". What are you asking if has been made official?

Regards,
Terje

RE: BLE Scan Packet Receive Latency When Done Along Side Mesh.

Anne van Rossum — Thu, 10 Oct 2019 16:56:43 GMT

And... has it been made official? :-)

RE: BLE Scan Packet Receive Latency When Done Along Side Mesh.

Sivaguru Ravi — Fri, 14 Jun 2019 06:26:52 GMT

Yes that is right.

Sorry for the late replsy

Regards

Sivaguru Ravi

RE: BLE Scan Packet Receive Latency When Done Along Side Mesh.

tesc — Fri, 07 Jun 2019 09:36:32 GMT

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

RE: BLE Scan Packet Receive Latency When Done Along Side Mesh.

Anne van Rossum — Fri, 07 Jun 2019 08:39:29 GMT

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. .

RE: BLE Scan Packet Receive Latency When Done Along Side Mesh.

tesc — Thu, 06 Jun 2019 14:18:50 GMT

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

RE: BLE Scan Packet Receive Latency When Done Along Side Mesh.

Anne van Rossum — Wed, 22 May 2019 10:43:53 GMT

1. It seems we actually get scan responses through the mesh.

2. So it is a matter of sending out the requests to have full-fledged active scanning functionality in the mesh. A small step, but very valuable because it does not introduce unnecessary competition wrt the radio peripheral, reduces code base, and likely causes fewer timing issues with other devices. Can you point us towards where/how you would implement it preferably in the mesh code so we are future-proof with respect to your implementation? We're assuming you will add it anyway in the near future. :-)

RE: BLE Scan Packet Receive Latency When Done Along Side Mesh.

tesc — Tue, 26 Mar 2019 14:41:41 GMT

Hi,

To me it sounds like the solution from Sivaguru Ravi is to use the scan module from the SDK in addition to the mesh stack, which means at any given point in time either the mesh stack or the scan module (but not both) is scanning. That means you should get scan responses from the SDK scan, and probably also relayed from the mesh stack when another device has sent a scan request.

Regards,
Terje

RE: BLE Scan Packet Receive Latency When Done Along Side Mesh.

Anne van Rossum — Tue, 26 Mar 2019 14:25:54 GMT

So, how does this match with the response by tesc who explained that the Link Layer of the Bluetooth mesh stack only supports passive scanning?

1. Either you have implemented an alternating approach between BLE scanning and the mesh stack operation like @tesc says.

2. Or perhaps another device is doing active scanning and this device picks up the scan responses while it does not itself send out scan requests?

RE: BLE Scan Packet Receive Latency When Done Along Side Mesh.

Sivaguru Ravi — Wed, 20 Mar 2019 13:30:50 GMT

yes

RE: BLE Scan Packet Receive Latency When Done Along Side Mesh.

Anne van Rossum — Tue, 19 Mar 2019 09:10:02 GMT

This also means scan responses?

RE: BLE Scan Packet Receive Latency When Done Along Side Mesh.

Sivaguru Ravi — Tue, 19 Mar 2019 06:15:36 GMT

I have combined ble scan example from sdk 11 and the mesh sdk light bulb example. The thing is since both mesh and the BLe soft device scan essentially uses the same scan apis internally we need not go making changes to mesh stack.

RE: BLE Scan Packet Receive Latency When Done Along Side Mesh.

Anne van Rossum — Mon, 18 Mar 2019 16:46:14 GMT

Where can the code be adjusted to also receive scan responses? At https://github.com/NordicSemiconductor/nRF5-SDK-for-Mesh there is a scanner_packet_process_cb in nrf_mesh.c. Are scan responses received but filtered. Or what's exactly the implementation?

RE: BLE Scan Packet Receive Latency When Done Along Side Mesh.

Sivaguru Ravi — Mon, 18 Mar 2019 08:50:04 GMT

I do get scan response but the scan is not consistent and the delay is over 5 seconds between packets.

RE: BLE Scan Packet Receive Latency When Done Along Side Mesh.

tesc — Thu, 14 Mar 2019 13:19:21 GMT

Hi,

The problem is that if you start modifying the mesh stack, in this case the link layer, it will no longer be covered by the qualification we have done and so you must do those qualifications yourself (which costs both time and money.) So the ideal situation is if you can either do with the current stack (taking a loss in latency and throughput) or if we add active scanning to the stack.

There are mainly two things required for active scanning:

1) The stack must provide both advertisement packets and scan response packets to the application. It does provide advertisement packets, but I am not sure if it does the same for scan response packets. If it doesn't then you must alter the stack. Also it requires listening on the correct channel.

2) You must send a scan request whenever you receive a scanable advertisement. You might be able to do that from the application (through the callback function) but you need to get the timing right and use the correct channel. You also need access to the radio peripheral for this, which I doubt is possible with current SoftDevices as you can only have one user of timeslots (and that user will be the mesh stack.) So basically that means the implementation must be done within the mesh stack.

Regards,
Terje

RE: BLE Scan Packet Receive Latency When Done Along Side Mesh.

bart — Tue, 12 Mar 2019 08:52:46 GMT

Righto, will do. And if i were to add it myself, where would i start? Can i add scan requests to the mesh code? Or is there a way to let the scanner callbacks, call a function of the mesh that handles scanned advertisements?

RE: BLE Scan Packet Receive Latency When Done Along Side Mesh.

tesc — Mon, 11 Mar 2019 14:35:04 GMT

Hi,

For details on future plans and roadmaps, please contact our Regional Sales Manager for your area. If you do not know who that is, please create a private ticket or send a private message and we will provide you with the contact details.

Regards,
Terje

RE: BLE Scan Packet Receive Latency When Done Along Side Mesh.

bart — Mon, 11 Mar 2019 12:45:12 GMT

Hmm, that's a shame, as i would like to be able to actively scan and listen to the mesh all the time.

Is this a feature that might be implemented later?

RE: BLE Scan Packet Receive Latency When Done Along Side Mesh.

tesc — Thu, 07 Mar 2019 14:50:53 GMT

Hi,

Unfortunately no. The Link Layer of our Bluetooth mesh stack only supports passive scanning, so there will not be sent any scan requests. For that you would have to use the SoftDevice API (for instance using the scan module from the SDK.) That means you alternate between giving radio time to BLE scanning and mesh stack operation, and so each of them will get less scan time.

Regards,
Terje

RE: BLE Scan Packet Receive Latency When Done Along Side Mesh.

bart — Tue, 05 Mar 2019 16:16:39 GMT

Do you also get scan responses?

RE: BLE Scan Packet Receive Latency When Done Along Side Mesh.

tesc — Tue, 08 Jan 2019 10:02:36 GMT

Hi,

I see that a lot of time has passed, but I will provide some more answers in case it is still relevant and for anyone reading this in the future.

For Android, the three advertising modes are typically 100 ms, 250 ms and 1000 ms advertising interval.

When combining scanning with the mesh stack, you can hook onto the advertisements getting scanned by the mesh stack.The mesh stack is already scanning most of the time, and it can forward the advertisements it scans to the application through a callback function that you set with nrf_mesh_rx_cb_set(). You can also hook into mesh_gatt_on_ble_evt() by adding a "case BLE_GAP_EVT_ADV_REPORT" there.

The other option is to use the scan module from the SDK, but in that case the scan module in the SDK and the mesh stack will compete for the radio, and every advertising packet will only reach one of them. If the mesh stack "wins" and gets most of the scan time then the scan through the SDK module will suffer.

Regards,
Terje

RE: BLE Scan Packet Receive Latency When Done Along Side Mesh.

Sivaguru Ravi — Thu, 06 Sep 2018 09:17:27 GMT

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.

RE: BLE Scan Packet Receive Latency When Done Along Side Mesh.

tesc — Wed, 05 Sep 2018 10:57:12 GMT

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