NCS Scan Request report RSSI value

RE: NCS Scan Request report RSSI value

dennis.sk.chan — Fri, 19 Jul 2024 02:59:03 GMT

hi Terje, please pass along the request for this feature as it was in nRF5 SDK. Especially since the config option, CONFIG_BT_CTLR_SCAN_REQ_RSSI, is in the documents, there should be a roadmap for this feature. Meanwhile, we will just work with what is available.

Thanks for your help,

Dennis

RE: NCS Scan Request report RSSI value

tesc — Thu, 18 Jul 2024 16:04:11 GMT

Hi,

I definitely see that there can be a use case for probing the RSSI of third party, scan only, centrals. Sadly I do not see any other ways to do that, than to get the RSSI from scan requests, since that is the only packets being sent from the central in that scenario.

Please note that in the case of third party centrals, RSSI will be an indication of signal strength, but you have no control over properties of the third party device such as antenna directionality, TX power, etc. The indicated signal strength is still correlated to distance, but it can only give a general idea, since what it really estimates is the strength of the radio link. Please note also that it estimates signal strength on the particular channel, and other signals on the same channel may impact the measurements. I do understand that you have used RSSI successfully in the past, which means you are probably in control of this, but I still mention this in case others see this answer in the future.

I will inform internally that there is request for such functionality, although I can not give any promises as to whether this will at some point be supported or not. You could however reach out to our sales people, who are more concerned with future plans, roadmaps, etc. Here in DevZone we mostly work on stuff that is already released. If you do not know who our sales representative for your area is, then please ask in a private ticket or private message, and we will let you know.

Regards,
Terje

RE: NCS Scan Request report RSSI value

dennis.sk.chan — Thu, 18 Jul 2024 02:59:14 GMT

hi Terje, that is too bad to hear as we were able to get the RSSI when we are using nRF5 SDK 17.1.0 on another project. We are using NCS for a different piece of hardware, and were hoping to have the same functionality as our other project. The use case is to gather additional information on BLE devices that are not advertising but are sending scan-request to our device. Getting the RSSI will tell us if the device is near our device. I hope you can suggest a workaround.

Cheers,

Dennis

p.s. will future NCS release also report RSSI for scan-request reports?

RE: NCS Scan Request report RSSI value

tesc — Wed, 17 Jul 2024 14:02:30 GMT

Hi,

The SoftDevice controller does not support reading RSSI from scan request packets. You will see if you enable the CONFIG_BT_CTLR_SCAN_REQ_RSSI configuration that you get the following (or similar) build warning:

warning: BT_CTLR_SCAN_REQ_RSSI (defined at subsys/bluetooth\controller\Kconfig.ll_sw_split:944) was
assigned the value 'y' but got the value 'n'. Check these unsatisfied dependencies:
BT_CTLR_SCAN_REQ_NOTIFY (=n), BT_LL_SW_SPLIT (=n).

May I ask what the use case is? We may be able to suggest a workaround.

Regards,
Terje