OFDM Frequency Offset Estimation via Partial Periodogram
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for estimating frequency offset in OFDM systems are either limited in estimation range, computationally expensive, or have high complexity, making them inefficient for real-time wireless communication.
Innovation Solution
A method using a partial periodogram for estimating frequency offset through envelope equalized processing, calculating partial periodograms for test values, and iteratively refining the estimates to reduce computational complexity and improve estimation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a full periodogram method is used for frequency offset estimation, then estimation accuracy is improved, but computational complexity and computation time increase significantly
Solution Approach 1:
The patent divides the frequency offset estimation process into multiple stages: first estimating a rough frequency offset using a reduced periodogram with fewer frequency points, then refining this estimate in subsequent stages with progressively higher resolution. This segmentation allows the system to achieve accurate estimation without computing the full periodogram at maximum resolution, thereby reducing overall computational complexity while maintaining measurement precision.
Solution Approach 2:
The patent computes the periodogram for only a partial set of frequency points rather than all possible frequency points. By calculating the periodogram at a reduced number of frequency locations sufficient for initial estimation, the system achieves acceptable accuracy with significantly reduced computation time and complexity, avoiding the excessive action of computing the complete periodogram.
2Productivity
If a reduced periodogram method is used to lower computational complexity, then computation time is reduced, but frequency offset estimation accuracy deteriorates
Solution Approach 1:
The patent performs a preliminary frequency offset estimation using a reduced periodogram with limited frequency points to obtain an initial rough estimate quickly. This preliminary action provides a starting point that is then refined in subsequent stages, allowing the system to achieve high accuracy without requiring the full computational effort from the beginning, thus balancing speed and precision.
Solution Approach 2:
The patent employs a dynamic, multi-stage estimation process where the frequency offset estimate is progressively refined. The first stage uses a coarse reduced periodogram for quick initial estimation, and subsequent stages iteratively improve the estimate with increased resolution. This dynamic approach adapts the computational effort to the estimation needs at each stage, achieving high accuracy efficiently.
Data Source
AI summary
A method and an apparatus of estimating a frequency offset in a wireless communication system are provided. An orthogonal frequency division multiplexing (OFDM) receiver performs envelope equalized processing (EEP) with respect to a reception signal and calculates a partial periodogram with a plurality of test values based on the reception signal which goes through the EEP. The OFDM receiver estimates a first frequency offset, a second frequency offset, and a third frequency offset based on two partial periodograms adjacent to each other among the partial periodograms for the plurality of test values.