Technical Deep Dive: Follow-Up Questions on Bluetooth Handshake Behavior
During our recent conversation, Sonova’s VP of Reliability shared that digital logs from my returned Sphere Infinio hearing aids showed repeated attempts to initiate Bluetooth handshakes without successful connections:
“We saw a lot of handshake attempts in your logs—not connections. That’s likely due to the ERA chip’s increased range, exposing the device to more nearby signals.”
This observation raises several questions about how the Sphere Infinio platform handles handshake traffic in high-signal environments.
Key Questions
-
Could repeated Bluetooth handshake attempts—particularly in high-signal environments—interfere with or destabilize an existing active connection on the Sphere Infinio platform?
-
Specifically, does the ERA chip’s extended power (and thus range) expose the device to more ambient handshake signals, and if the firmware isn’t prioritizing or isolating these properly, could that lead to the types of Bluetooth disruptions users are reporting?
Working Theories
In principle, a Bluetooth handshake attempt should not disrupt an existing active connection. The protocol is designed to support multiple roles and concurrent device interactions, especially in Bluetooth 5.x environments. However, in practice—particularly in complex systems like hearing aids—there are several plausible mechanisms by which handshake attempts could interfere with ongoing connections.
Given the ERA chip’s extended range and sensitivity, it’s reasonable to hypothesize that Sphere Infinio may be exposed to a higher volume of ambient handshake signals than previous platforms. If the firmware does not adequately prioritize or isolate these handshake attempts, the result could be dropped connections, streaming interruptions, or erratic link behavior.
Potential Contributing Factors:
-
Signal Saturation or Collision
High volumes of handshake attempts may overwhelm the device’s ability to manage simultaneous signals, leading to dropped connections. -
Firmware or Stack Limitations
If the Bluetooth stack lacks robust concurrency handling, handshake attempts may override or destabilize active sessions. -
Power Management Conflicts
Misinterpreted handshake attempts could trigger bandwidth reallocation or power-saving behaviors that interrupt streaming. -
Error Recovery Behavior
Failed handshakes may initiate resets or reinitializations that inadvertently drop active connections. -
Proprietary Link Interference
Timing conflicts between the proprietary binaural link and Bluetooth reconnection logic could contribute to instability.
I recognize that I am not an RF engineer or Bluetooth stack developer, and I welcome any expert input from those in experienced in this field can provide regarding these working theories.
Obviously, without knowing how Phonak’s firmware prioritizes handshake traffic—and whether mitigation strategies exist for high-signal environments—we likely won’t be able to specifically clarify the root cause of these disruptions…but curious what the technical experts here have to say 