Interference Cancellation for Powerline and Telephone Signal Coexistence
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Solution Overview
Problem
Interference between signals carried by electrical and telephone lines in a home distribution system, caused by shared frequency bands and coding methods, results in signal contamination and rate losses.
Innovation Solution
A method and device that filter the electrical line signal to estimate and subtract the interfering signal from the telephone line, using adaptive filtering and differential wide-band amplification to cancel interference, with complex number matrices modeling transmission channels and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If powerline communications and telephone lines share the same frequency band and are routed close together, then infrastructure utilization is improved, but signal interference increases
Solution Approach 1:
The patent introduces an intermediary signal processing system that includes a first modem for powerline communications and a second modem for telephone communications. These modems are equipped with interference cancellation capabilities that act as intermediaries between the conflicting signals, allowing both systems to coexist on shared infrastructure while mitigating mutual interference through adaptive filtering and signal estimation techniques.
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting filtering parameters and signal processing characteristics in response to varying interference conditions. The system monitors the electrical characteristics of the shared line and adapts its cancellation algorithms to maintain optimal performance under different operating conditions, thereby resolving the contradiction between shared infrastructure and signal quality.
2Reliability
If adaptive filtering is applied to cancel interference, then signal quality is improved, but device complexity increases
Solution Approach 1:
The patent implements preliminary action by pre-configuring the interference cancellation system with initial filtering parameters and signal processing settings. The system performs preliminary characterization of the transmission channel and establishes baseline cancellation parameters before actual communication begins, reducing the computational burden during active data transmission while maintaining high signal quality.
Solution Approach 2:
The patent applies dynamics by implementing adaptive filtering that automatically adjusts its parameters in response to changing interference conditions. The system dynamically updates its signal estimation models and cancellation parameters based on real-time monitoring of the electrical line characteristics, enabling it to maintain optimal interference cancellation performance while managing processing complexity through intelligent adaptation rather than fixed over-engineered solutions.
Data Source
AI summary
The present invention concerns a method and device for cancelling interference between a signal carried by a carrier current line of a system distributing digital services at the home of a subscriber and a signal carried by a telephone line of said system that is situated close to the carrier current line. The method is characterized in that it consists of obtaining the signal carried by the carrier current line, filtering it in order to obtain an estimate of the signal that disturbs the signal carried by the telephone line and subtracting this estimate from the signal carried by the telephone line.