Clock Bias Model for Mobile Positioning

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Solution Overview

Problem

Clock drift in reference signals used for positioning in mobile communication systems leads to positioning errors, particularly in applications like virtual reality and extended reality where accurate ranging is critical, as existing synchronization procedures are not sufficient to correct instantaneous clock offsets effectively.

Innovation Solution

An apparatus and method for generating a clock bias model that characterizes time-variable clock drift by updating parameters based on received reference signals, including positioning reference signals, to approximate and correct for clock offset and rate of change, using a machine-learning algorithm and reporting clock biases for improved positioning accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If existing synchronization procedures are used, then basic timing alignment is maintained, but clock drift leads to positioning errors in high-precision applications

Engineering Contradiction:
Improvepositioning accuracyVSAvoidclock synchronization reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies parameter changes by transitioning from static synchronization parameters to dynamic parameters that adapt to clock drift characteristics. The system estimates clock bias and its rate of change, then uses these time-varying parameters to compensate for timing errors in positioning measurements, thereby maintaining high positioning accuracy despite clock drift.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback mechanisms by continuously monitoring reference signals to estimate clock bias and rate of change. These estimates are fed back into the positioning calculation process to compensate for timing errors, creating a closed-loop system that actively corrects for clock drift effects and maintains synchronization reliability.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If clock bias modeling is implemented to correct drift, then positioning accuracy improves, but system complexity increases

Engineering Contradiction:
Improvepositioning accuracyVSAvoidsynchronization system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by estimating clock bias and rate of change in advance before positioning measurements are taken. The system performs preliminary clock characterization using reference signals, then uses these pre-computed parameters to correct positioning measurements, avoiding the need for complex real-time correction during the actual positioning process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent segments the clock correction problem into distinct components: clock bias estimation, rate of change estimation, and application-specific correction. By dividing the correction process into separate estimable parameters, the system reduces overall complexity while maintaining accuracy, as each parameter can be estimated independently using standard signal processing techniques.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4358605A1Clock bias
Publication Date: 2024.04.24 NOKIA TECHNOLOGIES OY
  • EP4358605A1 patent drawingFigure 1~2
  • EP4358605A1 patent drawingFigure 3
  • EP4358605A1 patent drawingFigure 4

AI summary

A method, apparatus and computer program is described comprising: receiving or obtaining plurality of reference signals, wherein the reference signals are transmitted by a node of a mobile communication system, wherein said reference signals are associated with a clock signal; generating a clock bias model for characterising a time variable clock bias of said clock signal for said plurality of reference signals, wherein said clock bias model comprises one or more parameters; generating modelled received signals, wherein each modelled received signal is based on one of the reference signals and the time-variable clock bias; and updating the parameters of the clock bias model so that the modelled received signals approximate to corresponding received signals.