Echo Compensation in Air Traffic Control Voice Systems
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Solution Overview
Problem
Existing voice communication systems in air traffic control suffer from delayed signal propagation, leading to echo disruptions when voice signals are digitized and transmitted in packets, causing signal delays exceeding 20 milliseconds, which disrupt communication by creating unpleasant echoes and preventing controllers from receiving incoming speech signals while transmitting.
Innovation Solution
A method and arrangement that utilize an echo compensation unit in the switching system to remove or compensate for the delayed voice signal portion from received signals, creating a cleaned voice signal that is superimposed with the original signal for immediate transmission back to the controller, and a push-to-talk mechanism to control signal emission and suppression, ensuring clear communication without constant echo cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If voice signals are digitized and transmitted in packets, then signal transmission efficiency is improved, but signal propagation delay increases exceeding 20 milliseconds causing echo disruptions
Solution Approach 1:
The system performs preliminary actions by capturing the controller's voice signal locally and preparing it for immediate playback before packet transmission occurs. The local voice signal is stored and timed to be played back at the exact moment the packet-transmitted voice signal arrives, ensuring continuous coverage without delay gaps or echo disruptions.
Solution Approach 2:
A local voice signal acts as an intermediary between the controller and the packet-transmitted voice signal. This local signal bridges the time gap created by packet transmission delays, providing immediate audio feedback to the controller while the delayed packet signal is being processed and transmitted.
2Object-affected harmful factors
If echo cancellation is continuously applied, then echo disruptions are eliminated, but system complexity and processing load increase
Solution Approach 1:
Instead of continuous echo cancellation processing, the system uses periodic action by triggering local voice signal playback only at specific moments - when packet transmission delays would create echo disruptions. This event-driven approach eliminates echoes only when necessary, reducing unnecessary processing and system complexity.
Solution Approach 2:
The system extracts and isolates the local voice signal from the main communication stream, handling it separately through dedicated playback timing mechanisms. This separation allows precise control over when the local signal is introduced, eliminating echoes without requiring complex real-time processing of the entire audio stream.
3Adaptability or versatility
If the controller transmits voice signals continuously, then communication coverage is improved, but the controller cannot receive incoming signals due to echo disruptions
Solution Approach 1:
The system dynamically adjusts the communication mode by switching between transmission and reception states based on incoming signal detection. When a packet-transmitted signal is detected at the receiving antenna, the system automatically transitions to reception mode, suppressing local voice signal playback and enabling the controller to receive incoming signals without echo disruptions.
Solution Approach 2:
The system uses feedback from the receiving antenna to control the transmission/reception state. When the receiving antenna detects an incoming packet-transmitted signal, this feedback triggers the suppression of local voice signal playback, automatically enabling reception capability without manual intervention.
Data Source
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AI summary
The invention relates to a method for radio communication between a controller and at least one road user, wherein voice signals (SF) are generated by a controller, wherein the voice signals (SF) of the controller are transmitted via a switching system (1) to a transmitting antenna (2) and are emitted by the latter as a radio signal, wherein voice signals (AF) are received via a receiving antenna (3) and transmitted to the switching system (1), wherein a squelch signal (SQU) is generated which indicates whether the signal present at the receiving antenna (3) contains voice messages, wherein the portion of the voice signal (SF) emitted by the controller, in particular the time-delayed voice signal (SF), is removed or compensated from the received voice signal (AF) and a purified voice signal (AF') is thus determined, and the purified voice signal (AF') is transmitted to the controller, wherein in the event that a squelch signal (SQU) is present,the cleaned speech signal (AF') is superimposed with the signal (SF) emitted by the controller and received by the switching system (1) without time delay and transmitted back to the controller.