Carrier Frequency Offset Estimation Using Weighted Sync Segments
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Solution Overview
Problem
Existing methods for estimating carrier frequency offset (CFO) in wireless communication networks face precision limitations due to unsynchronization between local and modulation carrier frequencies, which can lead to errors in signal demodulation, especially under varying channel quality conditions.
Innovation Solution
A method and apparatus that calculate multiple intermediate CFOs using selected sequence segments from both received and pre-stored sync sequences, weighting these calculations based on channel quality to generate a final CFO, thereby optimizing computing load and precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional CFO estimation methods using sync sequences are applied, then carrier frequency offset can be evaluated, but precision is limited due to unsynchronization between local and modulation carrier frequencies
Solution Approach 1:
The sync sequence is divided into multiple segments, and multiple intermediate CFO values are calculated from different segment combinations. These intermediate values are then weighted and combined to produce the final CFO estimate, improving precision by leveraging multiple independent measurements
Solution Approach 2:
The method dynamically adjusts the weighting factors of intermediate CFO values based on channel quality parameters. By changing the weight parameters according to channel conditions, the system optimizes the balance between different estimation components to achieve higher precision under varying synchronization conditions
2Measurement precision
If more sequence segments are selected and longer calculation steps are performed, then CFO estimation precision improves, but computing load increases
Solution Approach 1:
The system dynamically adjusts the number of sequence segments and calculation steps based on channel quality. When channel conditions are good, fewer segments are processed; when conditions deteriorate, more segments are included to maintain precision, thus optimizing the computing load-performance tradeoff
Solution Approach 2:
Instead of always processing the maximum number of sequence segments, the system applies partial action by selecting an appropriate subset based on channel quality. This avoids excessive computation when high precision is not needed, while ensuring sufficient processing when channel conditions require it
3Measurement precision
If sequence segment length and distance are extended, then CFO estimation precision improves, but processing time increases
Solution Approach 1:
The method dynamically adjusts sequence segment length and distance parameters based on channel quality metrics. By changing these parameters adaptively, the system achieves high precision when needed while minimizing processing time when channel conditions allow for faster, less precise estimation
Data Source
AI summary
In order to improve precision for estimating carrier frequency offset and reduce computing load, the present invention provides a method for estimating carrier frequency offset, which comprises steps of calculating a plurality of corresponding intermediate CFOs, respectively, based on one received sync sequence and one prestored sync sequences stored sync sequence through multi-step calculation, wherein, in each step, one corresponding intermediate CFO is calculated based on said received sync sequence and said pre-stored sync sequence; and weighting said plurality of intermediate CFOs in accordance with channel quality of a channel transmitting said received sync sequence to generate one final CFO. Each of the selected sequence segments may have a length and a mutual distance which are both, at its maximum, the full length of the sync sequence minus 1 so as to improve precision for the intermediate CFOs. Further, the estimation precision for the final CFO is improved by considering the impact of quality difference of reception channels on the intermediate CFOs.