Wireless Audio Packet Transmission Latency Reduction

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Solution Overview

Problem

Traditional wireless multi-channel audio systems face challenges such as interference from other Wi-Fi networks, infrastructure-induced latency, jitter buffer-induced latency, power-save mechanisms, and the need for synchronized playback across speakers, which affect the quality and synchronization of audio delivery.

Innovation Solution

The system reduces latency and improves packet delivery by disabling certain operating modes, adjusting jitter buffer sizes, retry counts, and channel switching based on wireless channel quality, and synchronizes playback by using beacon signals to adjust receiver clock signals, ensuring synchronized audio playback across multiple speakers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If wireless transmission is used to eliminate wires, then convenience is improved, but timing synchronization and audio quality deteriorate due to external interference and latency

Engineering Contradiction:
ImproveconvenienceVSAvoidtiming synchronization
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system performs preliminary actions by disabling operating modes that cause latency before audio transmission begins. This includes disabling power-save modes and frame aggregation modes that would introduce timing delays, ensuring that the wireless transmission path is optimized for isochronous delivery from the start

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts transmission parameters based on channel conditions. It monitors wireless channel quality and adapts by switching channels or adjusting transmission settings to maintain timing synchronization despite varying interference conditions, making the system flexible rather than static

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If standard Wi-Fi protocols are used, then ease of operation is improved, but timing precision deteriorates because Wi-Fi is designed for data packets without isochronous timing

Engineering Contradiction:
Improveease of useVSAvoidtiming precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The system changes critical transmission parameters to achieve isochronous timing. It modifies operating modes by disabling power-save and frame aggregation, adjusts jitter buffer sizes dynamically, and changes channel selection based on quality metrics. These parameter changes transform standard Wi-Fi into a timing-precise audio transmission medium

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system implements feedback mechanisms to monitor transmission quality and timing performance. It uses beacon signals for clock synchronization, monitors channel quality, and adjusts transmission parameters based on this feedback to maintain precise timing despite using standard Wi-Fi infrastructure

Inventive Principle:
Principle #23Feedback

3Reliability

If jitter buffer size is increased to handle wireless variability, then reliability is improved, but latency increases

Engineering Contradiction:
Improveaudio continuityVSAvoidlatency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system makes the jitter buffer size dynamic rather than static. It adjusts the buffer size in real-time based on measured channel conditions and timing variability. When channel conditions are good, the buffer is minimized to reduce latency; when conditions deteriorate, the buffer increases to maintain audio continuity, optimizing the trade-off continuously

Inventive Principle:
Principle #15Dynamics

4Reliability

If channel switching is performed to avoid interference, then audio quality is improved, but synchronization complexity increases

Engineering Contradiction:
Improveaudio qualityVSAvoidsynchronization complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system merges channel management and clock synchronization functions. Beacon signals serve dual purposes: they provide timing information for clock synchronization and carry channel quality information for interference detection. This unified approach allows coordinated channel switching while maintaining synchronization, reducing overall system complexity

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentUS10805753B2Multi-channel audio over a wireless network
Publication Date: 2020.10.13 CAAVO INC
  • US10805753B2 patent drawing
  • US10805753B2 patent drawing
  • US10805753B2 patent drawing

AI summary

Embodiments described herein reduce latency and improve packet delivery when transmitting audio packets from a source device to one or more sink devices. For example, one or more operating modes that introduce latency when transmitting packets may be disabled at the source device and/or sink device(s). Additionally, certain operational behavior of the source device and/or sink device(s) may be changed based on the quality of the channel used to transmit audio packets to further improve the latency. Such operational behavior includes changing the jitter buffer size of the sink device(s), the number of retry attempts performed by the source device when re-transmitting packets that have been lost, and changing the channel used to transmit the audio packets. Embodiments described herein further enable the synchronization of playback between the sink devices to ensure that sink devices playback audio packets in a synchronized fashion.