Discontinuous Transmission for Bluetooth Link Density

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Solution Overview

Problem

Bluetooth headsets in enterprise environments face challenges with user density due to increased mutual interference in crowded 2.4 GHz ISM RF band, leading to unsatisfactory link audio quality, as they were not optimized for widespread adoption in such settings.

Innovation Solution

Implementing discontinuous transmission (DTX) on short-range packet-based voice links like Bluetooth, which involves monitoring voice activity and transmitting zero-payload packets during pauses, reducing RF spectrum utilization and noise, and periodically sending comfort noise packets to maintain the perception of a continuous connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If continuous transmission is used on Bluetooth links, then audio quality is maintained, but user density is limited due to increased mutual interference in crowded 2.4 GHz spectrum

Engineering Contradiction:
Improveaudio qualityVSAvoiduser density
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent implements discontinuous transmission by periodically monitoring voice activity and switching between transmission modes. During voice activity, continuous transmission maintains audio quality. During pauses, transmission is suspended or reduced to periodic comfort noise packets, reducing spectrum utilization and allowing higher user density in the same RF environment.

Inventive Principle:
Principle #19Periodic action

2Reliability

If continuous transmission is used on Bluetooth links, then connection stability is maintained, but power consumption increases

Engineering Contradiction:
Improveconnection stabilityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system periodically monitors voice activity and dynamically adjusts transmission behavior. During voice pauses, transmission is suspended or reduced to periodic comfort noise packets, significantly reducing power consumption while maintaining connection stability through periodic monitoring and comfort noise transmission that keeps the logical connection active.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent changes transmission parameters dynamically based on voice activity detection. The transmission duty cycle is adjusted from continuous to discontinuous mode, and packet types are changed from voice data packets to comfort noise packets or null packets during pauses, optimizing the balance between connection stability and power consumption.

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If discontinuous transmission with zero-payload packets is used, then user density increases by reducing RF spectrum utilization, but connection continuity perception may deteriorate

Engineering Contradiction:
Improveuser densityVSAvoidconnection continuity perception
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent introduces comfort noise packets as an intermediary during transmission pauses. These packets contain synthesized noise that mimics background audio, serving as a mediator to maintain the perception of an active connection while actually reducing RF spectrum utilization. The comfort noise fills the audio gap created by suspended voice packet transmission, preventing users from noticing the discontinuity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3874730B1Discontinuous transmission on short-range packet-based radio links
Publication Date: 2023.03.01 PLANTRONICS INC
  • EP3874730B1 patent drawingFigure 1A
  • EP3874730B1 patent drawingFigure 1B
  • EP3874730B1 patent drawingFigure 2A

AI summary

Described herein are systems and methods for discontinuous transmission on short-range packet-based radio links. As one option, during a communication session with a far-end system on a short-range packet-based radio link, an audio stream received on an audio line in is monitored for voice-based signals. Based on monitoring the audio stream for the voice-based signals, a voice activity estimation signal is generated. While the voice activity estimation signal exceeds a predetermined threshold, one or more voice packets are generated based on the audio stream, and transmitted to the far-end system at one or more times. Also, in response to determining that the voice activity estimation signal is below the predetermined threshold, one or more zero-payload packets are transmitted to the far-end system at one or more subsequent times.