CPE Device Active RF Interference Cancellation
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Solution Overview
Problem
Cable customer premises equipment (CPE) devices face signal-processing problems due to strong wireless RF signals, particularly from LTE cellular telephones, which interfere with cable and RF splitters, leading to reduced data bandwidth and video channel availability, as existing methods like abandoning frequencies or increasing shielding are inadequate.
Innovation Solution
A CPE device with a processor, RF tuners, phase and amplitude adjustments, and a combiner system that processes both cable and interfering RF signals to partially cancel out the interference by adjusting signal parameters, ensuring effective operation amidst strong wireless signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If shielding of CPE devices is increased to reduce interfering RF signals, then isolation from interfering signals is improved, but the shielding is still insufficient to provide enough isolation from strong wireless signals
Solution Approach 1:
The patent captures the interfering RF signal through an antenna, converts it to electrical form, and then uses signal processing to invert and subtract it from the combined signal. This transforms the harmful interference into a useful cancellation reference, converting the harmful factor into a benefit for noise reduction
Solution Approach 2:
The patent introduces an intermediary antenna system that separately captures the interfering signal, which then serves as a reference for generating the inverted cancellation signal. This intermediary pathway allows the system to process and neutralize the interference without direct contamination of the main signal path
2Object-affected harmful factors
If frequencies experiencing significant RF interference are abandoned to reduce interference, then interfering signal impact is reduced, but data bandwidth and video channel availability are reduced
Solution Approach 1:
Instead of abandoning frequencies affected by interference, the patent captures the interfering signal, inverts it, and subtracts it from the combined signal. This allows the system to maintain full frequency utilization while actively canceling the harmful interference, thereby preserving both bandwidth and signal quality
Solution Approach 2:
The patent dynamically adjusts signal parameters including phase shifts and amplitude scaling of the inverted interfering signal to optimize cancellation effectiveness across different frequency conditions, allowing adaptive operation without frequency abandonment
3Adaptability or versatility
If CPE devices are designed to operate in the presence of strong wireless signals, then operational robustness is improved, but signal-processing problems persist without active cancellation
Solution Approach 1:
The patent enables CPE devices to operate robustly in the presence of strong wireless signals by capturing the interfering signal through a dedicated antenna, converting it to electrical form, inverting its phase, and subtracting it from the combined signal. This active cancellation process transforms the previously harmful strong wireless signals into manageable interference that can be mathematically removed, allowing reliable signal processing even in high-interference environments
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution allows CPE devices to maintain data bandwidth and video channel availability by effectively reducing interfering RF signals, ensuring stable operation even in the presence of strong wireless signals, thus enhancing the overall performance of CPE devices.
Implementation Method 1
an antenna configured to receive the interfering signal and supply the received interfering signal to a second RF tuner
Implementation Method 2
a combiner configured to combine the cable signal with the interfering signal to produce a combined signal
Data Source
AI summary
A customer premises equipment (“CPE”) device for use with a cable signal provided by a cable system. The CPE device includes an antenna and a signal processing system. The antenna receives an interfering radio frequency (“RF”) signal generated by one or more external wireless signal sources as a copy signal. The signal processing system receives the interfering RF signal, the cable signal, and the copy signal, modifies the copy signal to produce a processed copy signal, and combines the cable signal, the interfering RF signal, and the processed copy signal to produce a combined signal. The signal processing system also monitors error rate values of the combined signal, and adjusts the copy signal such that the copy signal at least partially cancels the interfering RF signal in the combined signal thereby reducing the error rate values of the combined signal.