Radio Signal Frequency Offset Determination Using Pilot Tone Sign Information

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Solution Overview

Problem

Existing methods for determining frequency offset in radio signals, particularly pilot tones, are inefficient, leading to suboptimal reception quality and channel separation in radio receivers.

Innovation Solution

A method and device that process the pilot tone using pilot oscillation to isolate sign information, determine and adjust the frequency offset, and provide it to improve reception quality by iteratively approximating a polynomial for the pilot oscillation, thereby reducing frequency deviation and phase offset.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional frequency offset determination methods are used, then the reception process can proceed, but the reception quality and channel separation remain suboptimal

Engineering Contradiction:
Improvefrequency offset determination precisionVSAvoidreception quality
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The method segments the frequency offset determination process into distinct phases: initial coarse determination using sign information from pilot tone processing, followed by iterative refinement using polynomial approximation. This segmentation allows the system to achieve both quick initial locking and high precision refinement, resolving the contradiction between measurement precision and reception quality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention implements a dynamic frequency offset determination method that adapts its approach based on the current offset magnitude. Initially, it uses sign information for rapid coarse correction, then transitions to polynomial-based iterative refinement for precise correction. This dynamic adaptation ensures optimal reception quality across varying offset conditions while maintaining determination precision.

Inventive Principle:
Principle #15Dynamics

2Object-affected harmful factors

If the frequency offset is not accurately determined and adjusted, then the system remains simple, but the signal-to-noise ratio and channel separation deteriorate

Engineering Contradiction:
Improvenoise and interferenceVSAvoidfrequency offset determination system complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The invention introduces sign information as an intermediary element in the frequency offset determination process. By extracting sign information from the pilot tone and using it to guide the polynomial approximation, the system achieves effective noise reduction and interference mitigation without requiring complex hardware modifications. The sign information acts as a simple yet powerful mediator that bridges the pilot tone processing and frequency offset correction.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The method replaces complex mechanical or hardware-based frequency tuning mechanisms with software-based signal processing techniques. Instead of using complex hardware circuits for frequency offset correction, the invention uses digital signal processing operations including sign information extraction, polynomial approximation, and iterative calculation. This substitution achieves superior noise rejection and channel separation while maintaining relative system simplicity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If iterative polynomial approximation is used to reduce frequency offset, then reception quality improves, but the processing time and computational effort increase

Engineering Contradiction:
Improvereception qualityVSAvoidfrequency offset correction time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The invention performs preliminary frequency offset correction using sign information before initiating the iterative polynomial approximation process. This preliminary action provides a coarse but accurate initial correction that significantly reduces the frequency offset to a smaller range. As a result, the subsequent iterative refinement requires fewer iterations to achieve the desired precision, thereby reducing the total correction time while maintaining high reception quality.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The frequency offset determination and correction is implemented as a periodic process with distinct phases: initial sign information-based correction, followed by iterative polynomial refinement at controlled intervals. This periodic structure allows the system to balance processing time and reception quality by performing intensive computational work only when necessary, rather than continuously, thus reducing overall processing time while maintaining optimal reception quality.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP2978140B1Method and device for determining a frequency shift of a radio signal and receiving device
Publication Date: 2019.05.15 ROBERT BOSCH GMBH
  • EP2978140B1 patent drawingFigure 1~2
  • EP2978140B1 patent drawingFigure 3~4
  • EP2978140B1 patent drawingFigure 5~6

AI summary

The invention relates to a method (600) for determining a frequency offset (102) between a pilot tone (104) encompassed by a radio signal (710) and a pilot oscillation (106) of a receiver for the radio signal (710). The method (600) comprises a processing step (602), a determination step (604), and a provision step (606). In the processing step (602), the pilot tone (104) is processed using the pilot oscillation (106) to isolate sign information (114) of the pilot tone (104). In the determination step (604), the frequency offset (102) is determined using the sign information (114). In the provision step (606), the frequency offset (102) is made available for further use.