Frequency Offset Estimation Using Interferer Signals
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Solution Overview
Problem
Existing Frequency Offset estimation methods in wireless communication systems fail to accurately compensate for Frequency Offset when the wanted signal is heavily polluted by interferers, leading to performance degradation, as they do not effectively utilize interferer information for estimation.
Innovation Solution
A Frequency Offset estimation system that incorporates interferer information, using a CIR estimator, wanted signal Frequency Offset estimator, and interferer Frequency Offset estimator, which combines these estimates based on a carrier-to-interference ratio to improve estimation accuracy, especially when the wanted signal is weaker than the interferer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wanted signal based Frequency Offset estimation algorithms are used, then the method is simple and straightforward, but the estimation accuracy deteriorates when the wanted signal is heavily polluted by interferers
Solution Approach 1:
The patent converts the harmful effect of strong interferers into a beneficial estimation resource. When the wanted signal is heavily polluted, the system switches to using the interferer signal itself for Frequency Offset estimation. The interferer, normally considered noise or disturbance, becomes the primary source for accurate FO estimation by analyzing its known structure and comparing received vs. expected interferer signals.
Solution Approach 2:
The patent changes the estimation parameter source from wanted signal to interferer signal based on signal quality conditions. When the wanted signal-to-interferer ratio falls below a threshold, the system transitions to using interferer-based estimation parameters, including interferer autocorrelation and cross-correlation metrics, to maintain accurate Frequency Offset estimation under degraded conditions.
2Measurement precision
If interferer information is utilized for Frequency Offset estimation, then the estimation accuracy improves when wanted signal is weaker than interferer, but the device complexity increases
Solution Approach 1:
The patent implements a dynamic estimation system that adapts its operation mode based on real-time signal conditions. The system continuously monitors the wanted signal-to-interferer ratio and dynamically switches between wanted-signal-based estimation and interferer-based estimation. This dynamic adaptation allows the system to maintain high accuracy across varying channel conditions without requiring permanently complex hardware for both modes.
Solution Approach 2:
The patent introduces an intermediary decision mechanism that selects between different estimation approaches based on signal quality metrics. This intermediary layer processes the signal-to-interferer ratio measurement and directs the estimation algorithm to use either wanted signal or interferer information, thereby managing system complexity through intelligent control rather than hardware duplication.
3Ease of operation
If conventional Frequency Offset estimation methods are used, then the system operation is simple, but the performance deteriorates when interferers are present
Solution Approach 1:
The patent implements feedback mechanisms where the estimated Frequency Offset and signal quality metrics are continuously monitored. The system uses this feedback to determine when to switch between estimation modes (wanted signal-based vs. interferer-based). This closed-loop approach ensures that the system automatically adapts to changing interference conditions, maintaining reliable performance without requiring complex manual intervention or reconfiguration.
Data Source
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AI summary
A Frequency Offset estimation system, user equipment, and a communication system are provided. The Frequency Offset estimation system comprises a first Frequency Offset estimator to estimate wanted signal Frequency Offset of a wanted signal in an input signal; a second Frequency Offset estimator to estimate interferer Frequency Offset of an interferer in the input signal; and a Frequency Offset estimation combiner to generate a combined Frequency Offset estimation by combining estimates of the wanted signal Frequency Offset and the interferer Frequency Offset.