Adaptive Signal Cancellation for Weak-Signal Receiver Isolation
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Solution Overview
Problem
Conventional methods for cancelling strong signals in communications systems, such as STAR and cellular phone networks, face challenges with inadequate isolation, slow adaptation, and correlation between strong and weak signals, leading to degraded performance and network inefficiencies, especially in dynamic environments like underwater acoustic communications.
Innovation Solution
A receiver system that includes a parametric cancellation circuit and adaptation logic to produce a cancellation signal, which is modulated and demodulated to isolate the weak signal, with adaptive parameter adjustment based on error signals to minimize interference, capable of operating in acoustic, optical, or RF frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional cancellation methods (circulators, summing junctions) are used to isolate strong signals, then some isolation is achieved, but the isolation level is insufficient (only 20 dB) when 100 dB or more is needed
Solution Approach 1:
The patent introduces an adaptive cancellation system that acts as an intermediary between the strong interfering signal and the weak desired signal. The system generates an adaptive estimate of the strong signal and subtracts it from the combined signal, effectively mediating the interference problem. This goes beyond passive isolation devices by actively creating and removing the interfering signal component.
Solution Approach 2:
The patent employs feedback mechanisms where the system continuously monitors the output signal quality and adjusts the cancellation parameters accordingly. The adaptive filter coefficients are updated based on the error between the desired weak signal and the actual output, creating a closed-loop system that improves isolation dynamically rather than relying on fixed passive isolation.
2Stability of the object's composition
If slow adaptation methods are used for signal cancellation, then system stability is maintained, but the adaptation process is too slow for dynamic environments where nodes move and propagation paths change rapidly
Solution Approach 1:
The patent transforms the static cancellation system into a dynamic one by implementing adaptive algorithms that continuously adjust cancellation parameters in real-time. The system responds to changing propagation conditions and node movements by updating filter coefficients dynamically, allowing it to track and cancel interfering signals even as the environment changes rapidly.
Solution Approach 2:
The adaptive cancellation system is self-adjusting, automatically modifying its own parameters based on the received signal characteristics. The system serves itself by detecting changes in the interference pattern and autonomously reconfiguring the cancellation filters without external intervention, enabling fast adaptation to dynamic conditions.
3Measurement precision
If adaptation is performed continuously to track changing signals, then cancellation accuracy is maintained, but the correlation between strong and weak signals degrades performance
Solution Approach 1:
The patent segments the adaptation process into distinct phases or uses multiple parallel adaptation paths. By dividing the cancellation task into separate processing streams or time segments, the system can apply different adaptation strategies to handle the correlation issue, maintaining accuracy while reducing the negative impact of signal correlation on reliability.
Data Source
AI summary
A receiver for cancelling strong signals from combined weak and strong signals includes: a first circuitry for inputting a weak and strong signal as an input; a parametric cancellation circuit for inputting a representation of the strong signal and an output of the first circuitry to produce a cancellation signal; a second circuitry electrically coupled to the parametric cancellation circuit for inputting the cancellation signal to produce a modulated output; a demodulator electronically coupled to the second circuitry for demodulating the modulated output to produce a demodulated output and an error signal, where the demodulated output is the data contained in the weak signal; and an adaptation logic circuit for inputting the representation of the strong signal, the demodulated output and the error signal to adaptively produce parameters for the parametric cancellation circuit. The parametric cancellation circuit further inputs the error signal and the parameters to produce the cancellation signal.