Wireless Audio Link Adaptive Frequency Hopping Interference

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Solution Overview

Problem

Existing wireless audio systems face interference issues from static and frequency hopping devices, particularly in shared frequency bands like the 2.4 GHz ISM band, which affects the reliability of audio signal transmission.

Innovation Solution

The system employs an adaptive frequency hopping (AFH) algorithm that analyzes channel traffic values to distinguish between frequency hopping and static interferers, using a comparison between maximum and average channel traffic values to filter out interference, and temporarily removes interfering channels to minimize static interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If adaptive frequency hopping is used to avoid static interferers, then interference from static devices is reduced, but the system becomes vulnerable to frequency hopping interferers that can still cause packet errors

Engineering Contradiction:
Improveinterference from static interferersVSAvoidtransmission reliability in presence of frequency hopping interferers
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The system continuously monitors packet error rates and uses this feedback to dynamically adjust the frequency hopping pattern. When packet errors are detected, the system analyzes whether they are caused by static or frequency hopping interferers and adapts the channel selection accordingly, creating a closed-loop control system that responds to interference conditions in real-time

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The frequency hopping pattern is made dynamic rather than static. The system continuously adapts the hopping sequence based on detected interference conditions, changing the frequencies and timing of transmissions to avoid both static interferers and frequency hopping interferers that may be present in the environment

Inventive Principle:
Principle #15Dynamics

2Reliability

If frequency hopping is used to minimize interference, then transmission reliability improves, but difficulty in detecting and measuring interference sources increases

Engineering Contradiction:
Improvewireless audio transmission reliabilityVSAvoidinterference source detection difficulty
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The system introduces an intermediary analysis layer that processes packet error information to infer interference characteristics. Rather than directly detecting interference sources, the system uses packet error rates as an intermediary metric to indirectly identify and respond to both static and frequency hopping interferers through pattern recognition

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system replaces direct physical measurement of interference sources with a signal-processing-based approach. Instead of using hardware to directly detect and measure interferers, the system substitutes a software-based analysis of packet errors and statistical patterns to identify and respond to interference conditions

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP3008717B1Wireless sound transmission system and method
Publication Date: 2017.08.09 SONOVA AG
  • EP3008717B1 patent drawingFigure 1~3
  • EP3008717B1 patent drawingFigure 4~5
  • EP3008717B1 patent drawingFigure 6

AI summary

There is provided a system for providing sound to at least one user (13), comprising at least one audio signal source (17) for providing an audio signal; a transmission unit (10, 110) comprising a digital transmitter (28) for applying a digital modulation scheme in order to transmit the audio signal as audio data packets from the audio signal source via a wireless digital audio link (12); at least one receiver unit (14) for reception of audio signals from the transmission unit via the digital audio link, comprising at least one digital receiver (61); and means (16, 64, 82) for stimulating the hearing of the user(s) according to audio signals supplied from the receiver unit; wherein the transmission unit is adapted to transmit each audio data packet according to an adaptive frequency hopping scheme at a frequency selected randomly from a list of transmission channels which is selected from a given frequency hopping set of transmission channels and which is updated on a regular basis; and wherein the transmission unit comprises a channel traffic detection unit (26, 33) for measuring, on a regular basis, the power in each channel of a monitored channel set consisting of at least a part of the channels of said frequency hopping channel set at the transmission unit for providing a channel traffic value (m) for each of these channels based on the measured power, the channel traffic values forming a metric vector, an interference detection unit (26, 34) for analyzing, on a regular basis, the metric vector in order to decide whether a static interference is present and, if so, to determine the channel (x max ) corresponding to the peak channel traffic, with the analysis of the metric vector including a comparison between a maximum value (d" max ) derived from the channel traffic values and an average value (d' av ) derived from the channel traffic values; and a channel blanking unit (26, 35) for temporarily removing, if it is decided that a static inference is present, the channel corresponding to the peak channel traffic and a number of channels around said channel from the list of transmission channels.