Differential Receiver Phase-Domain Frequency Offset Compensation
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Solution Overview
Problem
Conventional differential receivers face significant performance losses due to frequency offset, which is difficult to accurately estimate and compensate for, especially in noisy environments and fading channels, leading to high computational complexity, power consumption, and limited estimation range.
Innovation Solution
Frequency offset estimation and tracking are performed in the phase domain, reducing computational complexity and power consumption by eliminating the need for complex-valued multiplications and additions, allowing for a wider estimation range and accurate tracking even in fading channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequency offset estimation is performed using conventional auto-correlation methods, then frequency offset can be estimated, but computational complexity and power consumption increase significantly
Solution Approach 1:
The patent extracts only the phase information from the received signal using phase extractors, discarding the magnitude information. This phase extraction simplifies the frequency offset estimation by working solely with phase differences between consecutive symbols, eliminating the need for complex auto-correlation calculations while maintaining estimation accuracy.
Solution Approach 2:
The patent replaces the conventional complex-valued auto-correlation mathematical operations with a simpler phase-difference-based estimation method. By substituting the mechanical computation of complex correlations with phase extraction and subtraction operations, the system achieves the same frequency offset estimation with significantly reduced computational complexity and power consumption.
2Measurement precision
If frequency offset estimation uses conventional methods with multiple symbols, then estimation range is limited, but processing time increases
Solution Approach 1:
The patent segments the received signal into individual symbols and processes each symbol's phase independently using phase extractors. This segmentation allows the frequency offset estimation to be performed on a per-symbol basis, extending the estimation range without requiring processing of multiple symbols over time, thereby reducing processing time while maintaining or improving estimation accuracy.
Data Source
AI summary
A differential receiver which provides for estimation and tracking of frequency offset, together with compensation for the frequency offset. Estimation and tracking of the frequency offset is undertaken in the phase domain, which reduces computational complexity and allows frequency offset estimation and tracking to be accomplished by sharing already-existing components in the receiver. Compensation for the frequency offset can be performed either in the time domain, before differential detection, or in the phase domain, after demodulation, or can be made programmably selectable, for flexibility.