Half-Duplex PTT Feedback Reduction via Proximity Detection
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Solution Overview
Problem
In high-density environments, half-duplex push-to-talk (PTT) communications experience significant acoustic feedback due to the proximity of devices, which degrades voice transmission and playback, as existing echo cancellation methods designed for full-duplex systems are ineffective for half-duplex communications.
Innovation Solution
Implementing a method that determines proximity between devices and enables feedback reduction by either delaying playback or reducing playback volume when a device enters transmit-mode, using a near-field proximity profile to trigger these operations, thereby mitigating inter-device acoustic feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If acoustic echo cancellation based on digital signal processing is used to mitigate acoustic feedback, then acoustic feedback in full-duplex systems is reduced, but it is ineffective for half-duplex PTT communications due to unpredictable delay and jitter from inter-device feedback
Solution Approach 1:
The system performs proximity detection before PTT communication begins and proactively enables feedback reduction operations (playback delay or volume reduction) in advance. This preliminary action prevents acoustic feedback from occurring during transmission, rather than attempting to cancel it after the fact, making it effective for half-duplex systems where traditional echo cancellation fails due to unpredictable delays.
2Adaptability or versatility
If devices operate in high-density environments with close proximity, then communication availability is improved, but acoustic feedback between transmit-mode and receive-mode devices increases significantly
Solution Approach 1:
The system dynamically adjusts playback parameters (delay time or volume reduction) based on real-time proximity detection between devices. When a receive-mode device detects that a transmit-mode device is in close proximity, it automatically modifies its playback behavior adaptively. This dynamic response allows devices to operate effectively in high-density environments by continuously adjusting to changing spatial conditions.
3Object-affected harmful factors
If playback volume is reduced or playback is delayed to reduce feedback, then inter-device acoustic feedback is mitigated, but this requires real-time proximity monitoring and conditional operation control
Solution Approach 1:
The system implements a feedback loop where receive-mode devices continuously monitor proximity to transmit-mode devices using near field proximity profiles. Based on this feedback information, the system automatically determines when to enable feedback reduction operations and selects appropriate mitigation strategies (delay or volume reduction). This closed-loop feedback mechanism simplifies control by using environmental feedback to automatically trigger appropriate responses.
Data Source
AI summary
A method and system for enabling feedback reduction for half-duplex communications is provided. In operation, a crossing of a proximity threshold between a first device and a second device is determined and a feedback reduction operation is enabled based on the determination. The determination is based on a proximity check based on a near field proximity profile. The feedback reduction operation is at least one of reducing a playback volume to a predetermined level and delaying a playback. To delay playback, when a device enters transmit-mode, it may delay the transmission of received voice input. To reduce the playback volume, when a device enters receive-mode, it may reduce a volume of the audio output apparatus to a predetermined level.