Receiver Circuit Time Offset Estimation via Cross-Correlation
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Solution Overview
Problem
Traditional methods for estimating time offset in receiver circuits are inaccurate, especially when clock signals from different sources are used, and rely on synchronization accuracy, which can be flawed.
Innovation Solution
A receiver circuit with an estimation circuit performing cross-correlation operations on time-domain signals to estimate time offset independently of frequency offset, using a local sequence signal, and a time offset compensation circuit to adjust the signals accordingly, without relying on synchronization accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional time offset estimation methods are used when clock signals are generated from different clock sources, then the time offset must be estimated separately, but the estimation result is very susceptible to synchronization accuracy
Solution Approach 1:
The patent introduces a pseudo-random noise (PN) sequence as an intermediary signal to facilitate time offset estimation. By correlating the received signal with a locally generated PN sequence, the system can accurately determine time offset without being susceptible to synchronization accuracy issues. The PN sequence acts as a mediator that enables precise measurement independent of clock source synchronization.
Solution Approach 2:
The patent changes the estimation approach by using correlation-based parameter estimation instead of traditional methods. By transforming the time offset estimation problem into a correlation peak detection problem, the system achieves accurate measurement that is independent of synchronization accuracy. The parameter being estimated changes from direct time difference to correlation lag position.
2Device complexity
If traditional methods rely on frequency offset estimation results to compensate time offset, then the process is simplified, but the time offset estimation is inaccurate when clock signals are from different sources
Solution Approach 1:
The patent segments the offset compensation process into two independent stages: frequency offset estimation and time offset estimation. By separating these functions, the system can accurately estimate time offset using PN sequence correlation without relying on frequency offset results, while maintaining clear functional boundaries. This segmentation allows each estimation to be optimized independently.
Solution Approach 2:
The patent extracts the time offset estimation function from the frequency offset estimation process. By using PN sequence correlation specifically for time offset, the system removes the dependency on frequency offset estimation results. This extraction creates an independent, accurate time offset measurement path that works regardless of clock source synchronization.
3Reliability
If cross-correlation operation with local sequence signal is performed to estimate time offset independently, then synchronization accuracy dependence is eliminated, but the computational complexity increases
Solution Approach 1:
The patent applies partial correlation operations by using a truncated or segmented PN sequence for correlation. Instead of correlating over the entire signal duration, the system uses a sufficient portion of the PN sequence to achieve accurate time offset estimation. This partial action reduces computational complexity while maintaining the reliability benefit of independence from synchronization accuracy.
Data Source
AI summary
A method applicable to a receiver circuit, including: performing a cross-correlation operation upon at least one time-domain signal on at least one receiver path of the receiver circuit according to a local sequence signal, to estimate at least one time offset amount of the at least one time-domain signal as at least one time offset compensation amount; and, performing time offset compensation upon the at least one time-domain signal on the at least one receiver path according to the at least one time offset compensation amount.