Carrier Frequency Offset Estimation Using Correlation Window
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Solution Overview
Problem
Conventional OFDMA wireless communication systems face inaccuracies in initial carrier frequency offset estimation due to insufficient consideration of sample numbers and high resource demands, leading to suboptimal synchronization and link performance.
Innovation Solution
An apparatus and method for estimating and compensating the initial carrier frequency offset using a correlation window based on Cycle Prefix and preamble repetition length, which correlates received signals, converts values to phase, and compensates phase offsets for each segment number, enabling accurate synchronization with reduced hardware and software resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional frequency offset estimation method using complex conjugators and multipliers is applied, then frequency offset can be estimated, but hardware and software resources are excessively consumed
Solution Approach 1:
The patent extracts only the essential correlation operation from the conventional estimator, eliminating the need for complex conjugators, multipliers, and addition/average calculation units. By using a simplified correlation window approach that processes only N samples, the system achieves frequency offset estimation with significantly reduced hardware and software resources while maintaining adequate estimation accuracy.
2Measurement precision
If conventional averaging mechanism is used without considering sample numbers, then frequency offset estimation is performed, but estimation accuracy is insufficient
Solution Approach 1:
The patent changes the parameter of sample processing by explicitly considering the number of samples (N) in the correlation window. Instead of using a conventional averaging mechanism that ignores sample numbers, the system uses a correlation window of exactly N samples where N is determined by the preamble repetition length, thereby improving both estimation accuracy and efficiency.
3Measurement precision
If correlation window is not set based on Cycle Prefix and preamble repetition length, then signal correlation is performed, but synchronization accuracy is reduced
Solution Approach 1:
The patent applies preliminary action by pre-determining the correlation window size based on the Cycle Prefix and preamble repetition length before performing the correlation operation. This preliminary configuration ensures that the correlation window captures the complete repetitive pattern of the preamble, thereby achieving accurate synchronization without requiring complex adaptive window adjustment during signal processing.
Data Source
AI summary
The present invention relates to an apparatus for estimating and compensating a carrier frequency offset, and a data receiving method in a receiver of a wireless communication system. The apparatus correlates a received signal with a signal delayed by a predetermined period of the received signal in a correlation window, wherein the correlation window is set based on a Cycle Prefix (CP) and a preamble repetition length from a predetermined position, converts the correlated value into a phase value, compensates a phase of the converted result according to preamble segment numbers, and estimates an initial carrier frequency offset value.