May be a beacon qualified as BLE 4.x device without random?

[Aleksei Vegner]

I have a problem with some beacons which don't follow BLE specification. Namely BLUETOOTH SPECIFICATION Version 4.2, 4.4.2.2 Advertising Interval section. The problem is that my beacons don't have random addition at all... I noticed that something is wrong during continuous scans on my Thingy52 devices. For scans I use several observers and settings were chosen to have very unlikely listening pauses. Then some of the beacons started to disappear by pairs once an hour. The reason could be collisions of the advertising packets. So I decided to check it. And I was kind of shocked when i figured out that there isn't any random at all in the beacons. All new firmware was developed for measuring the actual intervals of my beacons. But the beacons are declared as BLE 4.2 devices. May it be possible? I checked my test firmware with several other beacons of other firms and all was OK with them. Although different models use different random intervals (10 ms, 50 ms). The following is my log from Nordic device for my beacons:

1. adv. int.: 8.0015 s, rand. int.: 0.0000 s
2. adv. int.: 8.0015 s, rand. int.: 0.0000 s
3. adv. int.: 8.0015 s, rand. int.: 0.0000 s
4. adv. int.: 8.0015 s, rand. int.: 0.0000 s
5. adv. int.: 8.0015 s, rand. int.: 0.0000 s
6. adv. int.: 8.0015 s, rand. int.: 0.0000 s
7. adv. int.: 8.0015 s, rand. int.: 0.0000 s
8. adv. int.: 8.0015 s, rand. int.: 0.0000 s
9. adv. int.: 8.0015 s, rand. int.: 0.0000 s
10. etc...

[Petter Myhre]

I'm having trouble understanding you. You refer to "some beacons" and Thingy52. Could you be more specific on what kind of hardware these beacons are? And what firmware you are running on them? Are you using our SoftDevices? Our SDK? How are you advertising in your code?

[Aleksei Vegner]

Sorry for possible misunderstanding. By saying my beacons I mean BOSCH GCC 30 TrackTags. Those beacons don't follow the requirement of the random addition for each advertising event. That's the problem. I scan for Bosch beacons on Nordic's Thingy 52. I developed special firmware for Thingy to measure random of the Bosch beacons. That's what I meant.

[Aleksei Vegner]

Yes, I use SDK 14.0.0 and SoftDevice 5.0.0 for my beacon scanners.

[Aleksei Vegner]

Raddot or Milwaukee beacons at least have random addition to avoid collisions but Bosch ones don't. So the question actually was may Bosch declare beacons as BLE 4.2 devices in such a case?

[Petter Myhre]

I understand. It is a bit strange, I'm not sure why they would implement it this way. Per spec it should be a random delay as you say.