Double Transmission Detection via Interference Cancellation
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Solution Overview
Problem
Double transmissions in signal transmission systems, particularly in Air Traffic Control, where multiple users transmit on the same carrier frequency, leading to detection challenges and only the strongest signal being perceived, potentially masking weaker signals.
Innovation Solution
A method for detecting double transmissions by employing interference cancellation and peak detection in colored noise, using a projection approach in the time domain and frequency domain to identify and cancel the strongest user's signal, allowing detection of secondary users and distinguishing between CLIMAX and non-CLIMAX transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple users transmit on the same carrier frequency simultaneously, then communication efficiency is improved, but signal detection accuracy deteriorates because only the strongest signal is perceived
Solution Approach 1:
The patent segments the received signal into multiple components by detecting spectral lines at different frequencies. The signal processing unit separates the strongest signal from weaker signals through frequency domain analysis, allowing independent detection and processing of each user's transmission on the same carrier frequency.
Solution Approach 2:
The patent transitions from time-domain signal analysis to frequency-domain analysis by detecting spectral lines. This dimensional change from time to frequency domain enables the system to distinguish between multiple signals that are overlapping in time, resolving the detection accuracy issue while maintaining communication efficiency.
2Device complexity
If conventional detection methods are used, then device complexity is reduced, but the ability to detect weak signals deteriorates
Solution Approach 1:
The patent performs preliminary frequency domain analysis to identify the frequencies of the strongest signals before attempting to detect weaker signals. This preliminary action of detecting spectral lines and identifying dominant frequencies enables subsequent targeted processing to extract weak signals that would otherwise be masked.
Solution Approach 2:
The patent introduces an intermediary frequency domain representation (spectral lines) between the raw received signal and the final detection output. This intermediary step transforms the complex time-domain superposition of multiple signals into separable frequency components, facilitating reliable weak signal detection without excessive complexity.
Data Source
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AI summary
Disclosed is a method for the detection of more than one signals contained in a receive signal, the method comprising: down-converting the receive signal, thereby providing a down-converted signal in a complex IQ base band; at least partially cancelling the strongest user in the down-converted signal, thereby allowing for the detection of a possible secondary user.