Predictive-Offset Time-Delay Estimation for Weak PIM Signals
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing time delay estimation (TDE) methods for passive intermodulation (PIM) cancellation in radio systems face challenges with weak PIM signals, where the correlation peaks are indistinguishable from noise, leading to inaccurate and slow convergence in synchronization processes.
Innovation Solution
A method and apparatus that utilize a predictive offset to synchronize excitation and stimulated signals, followed by cross-correlation to determine time delay, which is then used for PIM cancellation and other signal processing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional cross-correlation method is used for time delay estimation, then the method is simple to implement, but the accuracy deteriorates and convergence becomes slow when PIM signals are weak
Solution Approach 1:
The patent applies preliminary action by using a predictive offset to pre-synchronize the excitation and stimulated signals before performing cross-correlation. This preliminary synchronization ensures that the signals are approximately aligned, which enhances the visibility of correlation peaks and accelerates convergence, especially for weak PIM signals where traditional methods fail.
Solution Approach 2:
The patent implements feedback by iteratively updating the predictive offset based on the cross-correlation results. The estimated time delay from each iteration is fed back to adjust the predictive offset for the next iteration, creating a feedback loop that continuously refines the synchronization and improves both accuracy and convergence rate.
2Measurement precision
If cross-correlation is performed without predictive offset, then the implementation is simpler, but the correlation peaks become indistinguishable from noise floor for weak signals
Solution Approach 1:
The predictive offset performs preliminary synchronization that pre-aligns the signals before cross-correlation. This preliminary action enhances the signal-to-noise ratio in the correlation domain, making peaks distinguishable even for weak PIM signals, while the complexity is managed through efficient implementation.
Solution Approach 2:
The patent changes the parameter of signal alignment by introducing the predictive offset, which shifts the signals in time to achieve approximate synchronization. This parameter change transforms the correlation landscape, making peaks more prominent and distinguishable from noise, thereby improving detection accuracy.
Data Source
AI summary
The present disclosure generally relates to signal processing, and more specifically, the embodiments herein relate to a method for estimating a time delay between an excitation signal and a stimulated signal correlated with the excitation signal in a communication or measurement system, an apparatus and computer program product adapted for the same purpose. In one or more embodiments according to the present disclosure, there proposes a method for estimating a time delay between an excitation signal and a stimulated signal correlated with the excitation signal in a communication or measurement system. In the method, it acquires a predictive offset with which the stimulated signal is predicted to be approximately synchronized with the excitation signal. Then, the cross-correlation between the excitation signal and the stimulated signal with the predictive offset is acquired and the time delay is determined from the cross-correlation.