Connected RSSI on iPhone invalid

RE: Connected RSSI on iPhone invalid

_aj_ — Fri, 11 Jan 2019 05:53:31 GMT

Hi,

I know its been a long time since you posted this issue. We are facing the same issue on our side.

Were you able to find some solution for this? because same is happening on iphones 8 and after.

We are using BLE 5.0 nrf52832 as a beacon device. The rssi readings are fine in advertising mode but when iphone connects with the device it starts showing some invalid values.

We are blocked at this issue, a little help would be appriciable.

Thanks&Regards

Ajay

RE: Connected RSSI on iPhone invalid

Jiajun — Tue, 17 Jul 2018 03:18:37 GMT

Hi,

You call

"readRSSI()" only after you have connected by "centralManager" object.

You need also implement "peripheral(_:didReadRSSI:error:)" delegate in order to received the value.
If it fails, it reports the error.

RE: Connected RSSI on iPhone invalid

AmbystomaLabs — Fri, 13 Jul 2018 03:02:17 GMT

This is an odd problem. Since it reports correctly when not connected but wrong when connected.

I searched a bit. There was a bug in iOS10.1 that was precisely this problem that connected peripherals would not report an RSSI value. But of course 10.1 was a long time ago.

Happy to test them side by side next chance I get. But otherwise haven't heard or seen this phenomena.

Hopefully Nordic or someone else has some input.

RE: Connected RSSI on iPhone invalid

jloliveira — Thu, 12 Jul 2018 23:30:13 GMT

Hi AmbystomaLabs,

Thank you for your reply.

We are interacting with iphone and Nordic BLE peripherals for 4years and never had these issues. We are using iPhone8 with iOS11 and it reads RSSI on advertise without any problems, the issue occurs when reading RSSI after connecting to the nRF52840-based peripheral. Also, Android phones don't seem to have this problem and the iPhone reads RSSI fine after connecting to peripherals based on nRF51822.

Is there any justification for this?

Thanks,

João

RE: Connected RSSI on iPhone invalid

AmbystomaLabs — Thu, 12 Jul 2018 22:57:51 GMT

That's pretty normal for iOS. CoreLocation is even worse as with it when the location accuracy goes below a certain threshold it will report 0 for RSSI. But generally it occurs earlier for CL. Normally at about 30 feet. With CB you can normally get out to about 100 feet before it acts up.

I don't have my resources at hand, but the 0 will also get reported at +128dBm depending on how you format the data coming back from the API call.

In our applications, I just reuse the last good value and then keep a rolling average of good values. Some iPhones are worse than others. The iPhone 5(c) are the worst of BLE4+. Everything 6 and up is pretty comparable in performance.

I have never seen it to be BLE device dependent. And have tested many, many different beacon types with the same results.

One thing to remember also is that after about 2 minutes of getting data from CB, the OS will cut back on your resources and you will get many fewer data points from your advertisements.