Scan response packet sent by beacon without any scan request

[Jusang Kim]

reco_scan_req.PNG

Now i am doing a test of RECO beacon which use a nordic chipset, nrf51822. But something strange came up to me during the test with Ellisys bluetooth analyzer. The problem is that the RECo beacon sends scan response without any scan request. Please take a look of the highlighted area of the attached picture.

Any comments on this ?

My test configuration are as follows;

1. Wireless Test
2. Office environment : There are many Bluetooth scanner in the same room.
3. RECO beacon : the device address(D8 4E 4E E1 CD F9). I used the iBeacon example code.
4. My smart phone plays a role of scanner with the device address(4A F1 E3 4B A0 C2).
5. I used the software filter only to filter the devices. (D8 4E 4E E1 CD F9 & 4A F1 E3 4B A0 C2)

[Stian Røed Hafskjold]

Since you are filtering on the two devices D84E4EE1CDF9 and 4AF1E34BA0C2, maybe the scan request is not shown in the list if the scan request comes from another scanner that is filtered out?

[Stian Røed Hafskjold]

hmm.. that's a mystery. If the Ellisys does not receive the scan request, it can't possibly know which one is the receiver. Even if there was a bug in the Softdevice that caused the nRF to transmit a scan response without getting a request first, this packet would not contain any recipient information, so the Ellisys would not know which one is the receiver.

I think the only solution to this is that the Ellisys caches the scanner address and uses this as the address when it reports the recipient of the scan response, and that the cached address is not changed until it gets a scan request from another scanner. So I still believe that this is a scan response meant for another scanner that is filtered out.

Are you consistently getting this error? Do you still see this if you turn of the address filtering?