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(I tried to find the best forum to ask this, here seems the best place; please recommend alternative before downvoting)

Problem: while listening to music over bluetooth A2DP profile from a gps (zumo 660, bluetooth 2) to a headset (sena 20s, bluetooth 4.1), the music is interrupted when crossing path with other people on the road. Additionally, when music is not playing, assuming the failure occurred silently, the gps instructions are not sent either. Powering the headset down and back up causes the gps to rapidly fire all instruction that were queued since the failure.

This started in fall 2017 but got worse in 2018 and in 2019 lately it is almost certain to happen (maybe 3 times out of 5 encounters).

Hypothesis: since 2017, bluetooth 5 (BT5 from here on) has been introduced in smartphones. It's adoption increased with more and more people buying newer smartphones. I suspect these modern BT5 phones are emitting BT packets that cause the headset or gps to loose connection (or something causing the same symptoms).

What could be happening here? I suspect a few things:

a) BT5 has an extended advertising (255 bytes instead of 37). Obviously the advertising is connection-less (broadcast). Could this crash a BT2 stack not expecting more than 37 bytes?

b) Could the extra advertising bytes be mistaken for some RFCOMM control flow? This seems not very likely because the unique id would have low chance of matching, not the 3/5 I experienced.

c) could the BT5 simply pollutes the airwaves enough to mask a "clear-to-send" (CTS) control flow from the headset? This seems unlikely given the spread spectrum frequency hopping technology.

-what else?

-Do you know of any other keywords or articles describing this problem?

-how should a device defend itself (or facilitate recovery for the other) to avoid the problem?

Thanks.

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