Radio Receiver CFO Estimation Using Multi-Latency Autocorrelation
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Solution Overview
Problem
Existing radio receiver technologies face a trade-off between accuracy and range in estimating carrier frequency offset (CFO) due to phase wrapping effects and limited selection of auto-correlation lags, making it difficult to achieve precise synchronization.
Innovation Solution
A radio receiver device that combines autocorrelations with different latencies to estimate CFO, utilizing a multi-delay-branch algorithm to determine an accurate and wide-ranging CFO estimate by parallel processing and combining results from multiple autocorrelations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a larger auto-correlation lag D is used, then measurement accuracy is improved by reducing noise effect, but estimation range is reduced due to phase wrapping effects
Solution Approach 1:
The patent divides the CFO estimation task into multiple segments by using multiple autocorrelation lags (D1, D2, D3) with different properties. Each lag provides information about a specific portion of the CFO range, allowing the system to segment the overall estimation problem into manageable parts that can be solved simultaneously with complementary strengths.
Solution Approach 2:
The patent merges the results from multiple autocorrelation lags with different latencies to produce a final CFO estimate. By combining the strengths of each lag (short lags for range, long lags for accuracy), the system achieves both wide estimation range and high accuracy, resolving the trade-off between these two parameters.
2Adaptability or versatility
If a short auto-correlation lag is used, then estimation range is improved, but measurement accuracy is limited
Solution Approach 1:
The patent segments the estimation task by using multiple lags of different lengths. Short lags handle the range estimation while long lags handle the accuracy refinement, dividing the overall problem into functional segments that address different requirements simultaneously.
Solution Approach 2:
The patent combines the outputs of multiple autocorrelation calculations with different lags to achieve both wide range and high accuracy. The merging process integrates the complementary information from each lag, allowing the system to overcome the limitations of individual short or long lags alone.
3Measurement precision
If multiple autocorrelations with different latencies are used, then both accuracy and range are improved, but device complexity increases
Solution Approach 1:
The patent performs preliminary actions by pre-calculating and storing autocorrelation values for different lags during training or initialization. This allows the system to retrieve and combine pre-computed values during actual operation, reducing the computational complexity of real-time CFO estimation while maintaining the benefits of multiple lags.
Solution Approach 2:
The patent uses copies of the same autocorrelation calculation mechanism with different lag parameters. By reusing the same fundamental algorithm structure multiple times with varying inputs (different lags), the system achieves enhanced performance without proportionally increasing complexity, as the same code path is executed multiple times.
Data Source
AI summary
A radio receiver device is provided. The radio receiver device is arranged to receive a radio signal comprising a symbol sequence corresponding to a training sequence; to determine a first autocorrelation of said symbol sequence using a first autocorrelation latency; to determine a second autocorrelation of said symbol sequence using a second autocorrelation latency that is longer than the first autocorrelation latency; and to combine said first and second autocorrelations to determine an estimate of carrier frequency offset between the radio signal and the radio receiver device.