Link-Path Delay Estimation Using Coarse and Fine Phase Correlation
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Solution Overview
Problem
Conventional techniques for signal-path delay estimation lack sufficient resolution, particularly in systems of spatially-distributed sensors and radar-warning receiver systems, which hinders accurate synchronization and signal-source location.
Innovation Solution
A high-resolution link-path delay estimator is employed, which includes a master device and a remote device configured to communicate through a signal path, using a transmit signal with alternating symbols, phase-shifting, and correlating noise-reduced sampled signals to estimate signal-path delay with precision, combining coarse and fine-delay estimates for accurate round-trip delay determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional delay estimation techniques are used, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The delay estimation process is divided into two independent stages: coarse delay estimation using integer symbol period increments, and fine delay estimation using fractional symbol period adjustments. This segmentation allows each stage to be optimized separately, achieving high overall precision without excessive complexity in either stage.
Solution Approach 2:
The invention transitions from discrete integer-based delay measurements to a two-dimensional estimation space that includes both integer symbol periods and fractional symbol periods. This dimensional expansion enables sub-symbol precision by adding the fine delay dimension to the coarse integer delay foundation.
2Measurement precision
If high-resolution delay estimation is implemented, then synchronization accuracy is improved, but processing time increases
Solution Approach 1:
The coarse delay estimation is performed first to establish an initial delay value using integer symbol periods. This preliminary action provides a starting point that is then refined by the fine delay estimation stage, avoiding the need to search the entire delay space from scratch and reducing overall processing time.
Solution Approach 2:
By separating delay estimation into coarse and fine stages, the search space is divided into two manageable regions. The coarse stage handles large delays efficiently with integer steps, while the fine stage focuses computational resources on small fractional adjustments, optimizing the trade-off between precision and processing time.
Data Source
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AI summary
Embodiments of a high-resolution link-path delay estimator and method are generally described herein. The high-resolution link-path delay estimator may estimate a signal-path delay of a signal path between a master and remote device. The high-resolution link-path delay estimator may phase-shift a transmit signal of alternating symbols by phase-shift values and may sample a loopback signal. A noise-reduced version of the sampled signal output may be correlated with a step function to generate a correlation value for each of the phase-shift values. One of the phase-shift values may be selected to generate a fine-delay estimate which may be added to a coarse delay estimate to determine the signal- path delay. The coarse delay estimate may be an estimate of the signal-path delay to a nearest symbol period of the transmit signal and the fine-delay estimate may be an estimate to within a fraction of the symbol period.