Mobility State Estimation Using Doppler Shift and Timing Advance

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Solution Overview

Problem

Current mobility state estimation in wireless networks is limited, particularly in RRC_CONNECTED mode, with simplistic methods that struggle to accurately determine mobility state for individual devices and are not comprehensive or reliable, especially in distributed radio access environments.

Innovation Solution

A method involving network nodes that obtain and communicate mobility state information, including direction and speed, based on uplink signals, downlink reference signals, and stored data, using machine learning to enhance estimation accuracy and autonomy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional mobility state estimation methods are used in RRC_CONNECTED mode, then the implementation is simple, but the measurement precision and reliability of mobility state determination are insufficient

Engineering Contradiction:
Improvemobility state estimation accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system divides mobility state estimation into multiple independent components: individual mobility measurements from each UE, separate measurement types (uplink signal quality, downlink reference signals, handover frequency, speed measurements), and modular processing stages. This segmentation allows each component to be optimized independently while maintaining overall system manageability despite increased complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A machine learning model serves as an intermediary between raw mobility measurements and final mobility state determination. The ML model processes multiple input parameters (signal quality metrics, handover frequencies, speed data) and transforms them into accurate mobility state classifications, resolving the contradiction by handling complexity internally while providing precise outputs.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If network-based mobility control is implemented, then handover management is centralized, but the responsiveness to individual UE mobility conditions is reduced

Engineering Contradiction:
Improvehandover management reliabilityVSAvoidmobility state detection speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The system implements continuous feedback loops where UEs report mobility measurements (signal quality, handover performance, speed) back to the network in real-time. The network uses this feedback to dynamically adjust handover parameters and make informed decisions, maintaining centralized control while responding rapidly to individual UE conditions through automated feedback-driven adjustments.

Inventive Principle:
Principle #23Feedback

3Loss of information

If basic mobility state parameters are used, then the information required is minimal, but the comprehensiveness of mobility state information is insufficient for informed handover decisions

Engineering Contradiction:
Improvemobility state information completenessVSAvoiddata transmission volume
Core Design Contradiction:
Loss of informationVSQuantity of substance

Solution Approach 1:

The system extracts only the most relevant mobility features from extensive measurement data using machine learning techniques. Instead of transmitting all raw measurement data, the ML model identifies and extracts key features (signal quality trends, handover frequency patterns, speed characteristics) that are most predictive of mobility state, reducing data volume while maintaining information completeness.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system transforms raw mobility measurements into derived parameters and features that are more informative for mobility state determination. Rather than using basic parameters alone, the system calculates composite parameters (signal quality trends, handover success rates, speed profiles) that provide comprehensive mobility information in a compact form suitable for efficient transmission and processing.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Improves the reliability and comprehensiveness of mobility state estimation, enabling more informed handover decisions and resource management in wireless networks, particularly in distributed radio access environments.

Implementation Method 1

The obtained one or more mobility state related parameters comprises one or more of: a doppler shift in the uplink signals sent by the wireless device

Methodology Applied
Scientific EffectDoppler shift: Doppler Effect

Implementation Method 2

a timing advanced measured in the uplink signals sent by the wireless device

Methodology Applied
Scientific EffectTiming advance:

Data Source

PatentUS20240244499A1Methods and apparatus for providing mobility state information
Publication Date: 2024.07.18 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • US20240244499A1 patent drawing
  • US20240244499A1 patent drawing
  • US20240244499A1 patent drawing

AI summary

Methods and apparatus are provided for providing mobility state information in a radio access network. In certain embodiments a method is performed by a first network node of a radio access network. The method includes obtaining one or more mobility state related parameters and determining mobility state information of a wireless device in a connected mode with the radio access network. The mobility state information is determined based on the one or more mobility state related parameters. The first network node communicates the determined mobility state information to a second network node.