OFDM Synchronization Timing Detection Using Variance Minimization
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Solution Overview
Problem
Existing synchronization timing detection methods for OFDM signals in mobile terminal test apparatuses are prone to errors due to noise interference, leading to incorrect detection of symbol ends.
Innovation Solution
A receiving device that generates a delay signal by delaying the received OFDM signal by a valid data length of one symbol, calculates the variance of physical quantity differences between the received and delay signals, and detects symbol positions based on the minimum variance peak, thereby generating accurate synchronization timing signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If correlation-based synchronization timing detection is used, then the detection process is simple, but detection accuracy deteriorates due to noise interference causing false peak detection
Solution Approach 1:
The patent divides the detection process into multiple stages: first performing correlation detection to identify candidate timing positions, then applying variance calculation on segmented signal portions around these candidates to confirm the true synchronization point. This segmentation approach maintains simplicity while improving accuracy by breaking down the detection into manageable steps that filter out noise-induced false positives.
Solution Approach 2:
The patent introduces variance calculation as an intermediary verification step between correlation detection and final timing determination. Instead of directly using correlation peaks, the system calculates variance of signal portions around candidate points to filter out false detections caused by noise, thereby improving accuracy without significantly increasing overall complexity.
2Device complexity
If only correlation peak position is used for synchronization detection, then the detection method is simple, but reliability deteriorates due to false detection from noise
Solution Approach 1:
The patent implements a feedback mechanism where the initial correlation-based timing estimate is fed into a variance calculation stage that verifies and corrects the timing position. This feedback loop ensures that false detections from noise are identified and corrected, significantly improving reliability while maintaining a relatively simple overall structure through the use of standard signal processing operations.
3Measurement precision
If variance calculation is performed over the entire signal, then detection accuracy is improved, but computational complexity increases
Solution Approach 1:
The patent segments the variance calculation to be performed only on specific portions of the signal around correlation-identified candidate timing positions, rather than calculating variance over the entire signal. This segmentation maintains detection accuracy by focusing computational resources on relevant signal portions while significantly reducing overall computational complexity.
Solution Approach 2:
The patent applies partial action by performing variance calculation only on necessary signal portions around candidate timing points rather than the complete signal. This partial processing approach achieves sufficient detection accuracy without the excessive computational burden of processing the entire signal, optimizing the balance between accuracy and complexity.
Data Source
AI summary
A receiving device 100 includes a reception unit 10, a delay signal generation unit 22, a difference calculation unit 23 that calculates a phase difference between the received signal and the delay signal, a variance calculation unit 24 that calculates a variance of the phase difference within a plurality of calculation sections while sliding a set of the plurality of calculation sections which are set corresponding to a cyclic prefix group assigned to a predetermined symbol group included in the received signal, together on the time axis, a symbol detecting unit 25 that detects a position of a symbol in the symbol group on the time axis, based on the position of the minimum peak of the variance on the time axis, and a synchronization timing signal generation unit 29 that generates a synchronization timing signal, based on information on the position of the symbol on the time axis.