Band Averaging Circuit for Carrier Frequency Offset Estimation
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Solution Overview
Problem
Conventional methods for estimating carrier frequency offset in multi-band multi-carrier communication systems are inaccurate due to potential serious mistakes in carrier frequency offset ratios, affecting the quality of received signals and increasing inter carrier interferences (ICI).
Innovation Solution
A band averaging circuit and method that utilize a frequency offset estimation unit to generate carrier frequency offset ratios and a frequency offset adjustment circuit to calculate a weighted average carrier frequency offset ratio, improving the accuracy of carrier frequency offsets by performing weighted averaging based on comparison results and center frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional averaging method is used to calculate carrier frequency offset ratio, then computational simplicity is maintained, but estimation accuracy deteriorates due to serious mistakes in individual carrier ratios
Solution Approach 1:
The patent applies local quality by assigning different weights to different carrier frequency offset ratios based on their individual qualities or reliability. Instead of uniform averaging, each carrier's frequency offset ratio is weighted according to its estimation quality, allowing the system to give more importance to reliable measurements and less to erroneous ones, thereby improving overall estimation accuracy without requiring complex error detection mechanisms
Solution Approach 2:
The patent changes the parameter of averaging from simple arithmetic mean to weighted mean, where weights are determined based on comparison results of different carrier frequency offset ratios. This parameter change allows the system to dynamically adjust the contribution of each carrier's frequency offset estimation, improving robustness against serious mistakes in individual carriers while maintaining computational efficiency
2Reliability
If simple average of carrier frequency offset ratios is calculated, then calculation complexity is reduced, but reliability of the estimation deteriorates when serious mistakes occur in individual carriers
Solution Approach 1:
The patent evaluates the quality of each carrier frequency offset ratio estimation and applies local quality weighting, where reliable estimations receive higher weights and unreliable ones receive lower weights. This approach maintains high processing speed by avoiding complex iterative error detection, while improving reliability through selective weighting based on comparison results
Solution Approach 2:
The patent implements a feedback mechanism where the comparison results of different carrier frequency offset ratios are used to determine weights for the weighted average calculation. This feedback loop allows the system to automatically adjust the influence of each carrier's estimation based on its consistency with others, improving reliability without significantly increasing processing complexity
Data Source
AI summary
A band averaging circuit and a related method for estimating a carrier frequency offset are applied in a multi-band multi-carrier communication system. A packet of the multi-band multi-carrier communication system is transmitted via a plurality of carriers. The band averaging circuit includes a frequency offset estimation unit for generating a plurality of carrier frequency offset ratios corresponding to the carriers according to a received packet; and a frequency offset adjustment circuit coupled to the frequency offset estimation unit for calculating a weighted average carrier frequency offset ratio according to carrier frequency offset ratios and comparison results of the carrier frequency offset ratios, and also for calculating a carrier frequency offset of each carrier according to the weighted average carrier frequency offset ratio and a center frequency of the carrier.