RF Interference Cancellation in Wired Data Links
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Solution Overview
Problem
Wired data communication links in hostile environments, such as automotive and industrial settings, suffer from radio frequency (RF) interference, which increases bit-error-rate (BER) and can cause link drops due to the cable acting as an antenna, degrading receiver performance and requiring complex analog and digital signal processing.
Innovation Solution
An apparatus and method for on-the-fly detection and cancellation of RF interference using adaptive feed forward and feedback digital filters, with bootstrapping configurations based on signal characteristics and FFT, DPLL, or counter-based methods, to reduce interference without increasing PHY complexity or power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adaptive feed forward and feedback digital filters are used for RF interference cancellation, then signal-to-noise ratio is improved and communication reliability is maintained, but device complexity increases
Solution Approach 1:
The patent applies bootstrapping methods (FFT-based, counter-based, or DPLL-based) to pre-initialize the adaptive filters with estimated interference characteristics before full adaptive processing begins. This preliminary action provides a good starting point for the adaptive algorithms, enabling faster convergence and more reliable interference cancellation while reducing the time and computational resources needed for adaptation.
Solution Approach 2:
The patent implements feedback mechanisms where the output of the adaptive filters is continuously monitored and used to adjust filter coefficients in real-time. The error signal between the received signal and the filtered output feeds back to the adaptive algorithm, enabling continuous optimization of interference cancellation performance and maintaining communication reliability under varying interference conditions.
2Reliability
If complex digital signal processing blocks are used to handle RF interference, then receiver performance is improved, but power consumption increases
Solution Approach 1:
By using bootstrapping methods to pre-estimate interference characteristics and initialize adaptive filters, the system reduces the number of iterations required for convergence. This preliminary action decreases the computational burden during active processing, thereby reducing power consumption while maintaining effective interference cancellation and receiver performance.
Solution Approach 2:
The patent applies adaptive filtering selectively to cancel narrowband interference rather than processing the entire signal spectrum uniformly. By focusing computational resources only on the frequency regions affected by RF interference, the system achieves effective interference cancellation with reduced overall processing requirements and lower power consumption.
3Reliability
If tight specifications for analog front-end are required to handle RF interference, then communication reliability is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent converts the harmful effect of RF interference into a detectable signal characteristic that can be exploited by the adaptive filtering system. By treating the interference as a identifiable pattern rather than random noise, the system can selectively cancel it using digital signal processing, thereby relaxing the requirements for analog front-end filtering and shielding while maintaining communication reliability.
Solution Approach 2:
The patent introduces digital signal processing blocks as intermediaries between the analog front-end and the baseband processing. These digital filters act as a mediator that can selectively remove RF interference without requiring the analog front-end to have extremely tight specifications, thereby simplifying manufacturing while maintaining receiver performance through digital intervention.
Data Source
AI summary
An apparatus and method are provided for cancellation of RF interference coupling into a wired data communication link. The apparatus comprises: an input configured to provide an input signal, the input signal forming a digital representation of a signal received via the wired data communication link; an adaptive feed forward digital filter configured to filter the input signal in order to provide a feed forward filtered input signal; an adaptive feedback digital filter configured to filter a superposition signal in order to provide a feedback filtered output signal, the superposition signal representing an addition of the feed forward filtered input signal and the feedback filtered output signal; and an adjuster, configured to adjust the adaptive feed forward digital filter and the adaptive feedback digital filter based on an error signal, the error signal representing a difference between the input signal and the superposition signal.