Adaptive Interference Canceling System Using Frequency Domain Filtering
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Solution Overview
Problem
Conventional filtering techniques are inadequate in effectively canceling noise and interference, such as impulse noise, RF interference, and crosstalk, in telecommunication systems, due to their inability to adapt quickly to changing interference patterns and high computational complexity, leading to reduced signal quality and performance.
Innovation Solution
A system that separates signals into differential and common modes, estimates noise or interference in the common mode, and subtracts it from the differential mode using frequency domain filtering, with adaptive algorithms like LMS and RLS, to generate a signal substantially free of interference, while minimizing system complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional filtering techniques are used to remove noise and interference, then some interference reduction is achieved, but the system cannot adapt quickly to changing interference patterns and computational complexity increases
Solution Approach 1:
The patent implements adaptive filtering algorithms (LMS, RLS) that dynamically adjust filter coefficients in real-time based on feedback signals. This allows the system to adapt quickly to changing interference patterns by continuously updating the filter parameters, transforming the static filter into a dynamic system that learns from incoming signals.
Solution Approach 2:
The patent employs feedback mechanisms where the output of the filter is fed back into the system to update the filter coefficients. The error signal from the feedback path is used to adjust the adaptive filter parameters, enabling the system to learn from its own performance and improve interference cancellation over time.
2Reliability
If conventional filtering techniques are used to remove noise and interference, then some interference reduction is achieved, but system complexity and computational requirements increase
Solution Approach 1:
The patent changes the parameter representation from time domain to frequency domain by using Fast Fourier Transform (FFT). This transformation allows the filtering operation to be performed more efficiently using frequency domain convolution instead of time domain correlation, reducing computational complexity while maintaining filter effectiveness.
Solution Approach 2:
The patent replaces complex time-domain adaptive filtering operations with frequency-domain processing using FFT. This substitution transforms the computational burden from complex time-domain convolutions to more efficient frequency-domain operations, reducing the overall computational complexity of the system.
3Reliability
If time domain adaptive filtering is used to cancel interference, then interference cancellation is attempted, but the desired signal acts as noise limiting convergence speed and accuracy
Solution Approach 1:
The patent transforms the signal processing from the time domain to the frequency domain using FFT. This dimensional change allows the system to process frequency components separately, avoiding the problem where the desired signal masks the error signal in the time domain. The frequency domain representation separates the signal components, enabling faster and more accurate convergence.
Data Source
AI summary
A communication system adaptively cancels noise and/or interference from signals communicated through a communication channel, such as signals communicated by a telecommunication network. The system, based on a common mode signal of a received signal, generates an estimate of noise or interference within a differential mode signal of the received signal. The system then subtracts the estimate from the differential mode signal in an effort to remove noise from the differential mode signal thereby providing a differential mode signal that is substantially free of the estimated noise or interference.