Direct Advertising with Beacons

[malpmode]

Hello everyone,

I have questions concerning direct advertising. I have read this and other posts from several years ago which provided some useful information.

devzone.nordicsemi.com/.../connecting-to-only-one-central-how-to-detailed

Maybe someone can help me with following questions.

1. I think that it is possible to advertise as beacon/peripheral to only one central scanner with the MAC Address (known MAC from the central). Do you agree with that?

1.1 Is there any example how to do that at this level? I know, there are examples of connecting peripherals with the peer manager, but I simple want to advertise to one central scanner to ignore other scanner around the device (phones, ...).

2. From my perspective there are two possibilities to configure this. Directly over the softdevice oder with ble_advertising.c. What is the main difference between that two options and which configuration possibility do you suggest.

3. Are there any things that I must configure on the Central Scanner to support direct advertising?

Thank you for your time and your help!

[Vidar Berg]

Hello,

What is the motivation for wanting to use directed advertisement? Usually you include a unique ID in the beacon payload (e.g. an UUID) which lets the scanner recognize the beacon as your beacon. The problem with directed advertisement is that the packets do not carry any data payload and is therefore not suited for connectionless beacon applications.

Best regards,

Vidar

[malpmode]

Hello,
Thank you for your answer. The aim behind that is to recognize as peripheral/beacon, if the current location is in the range of a configured central/scanner. Unfortunatly, after an advertisment, sometimes the scan request include an other MAC address than expected, if other active scanners are in range (I think the other scanners just take over of this small scan duration of the beacon). If direct Advertising to the specific central/scanner is possible it would be ensured, that the scan request is always comming from the right device. Maybe there is a way to ensure that after one advertisment to the central, the right scan request mac will be returned although other active scanners are in range. Establishing a connection only provides a maximum of 20 slots and has a higher energy consumption, therefore it must be done without any connection. Maybe you know any idea to check as beacon if my beacon is in a certain area or not, if direct advertising cannot fit these requirentments.

Best regards and thank you for your time.

[Vidar Berg]

Thanks for the clarification. So the problem, if I understand it correctly, is that you don't want your beacons to respond to scan requests coming from unknown scanners. If so, that is something you may be able to achieve with whitelist device filtering. In case you don't know, "White list" is a feature that's part of the BLE spec., see core spec. 5.2, vol. 6, part B, section 4.3.1 for details.

The challenge maybe is how you are going to maintain the whitelist. Will the beacons always know what address the scanner will have?