Mobile Station Synchronization Accuracy Estimation

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Solution Overview

Problem

The existing multilateration process for determining the position of a mobile station in wireless communication networks lacks accurate information about synchronization accuracy, leading to potentially pessimistic positioning estimates and unnecessary involvement of multiple base transceivers, which can result in insufficient or overly pessimistic positioning accuracy.

Innovation Solution

The mobile station and base station subsystem (BSS) collaborate to estimate and transmit synchronization accuracy information, allowing the Serving Mobile Location Center (SMLC) to make more precise positioning estimates by reporting estimated synchronization accuracy and BTS timing advance accuracy, thereby optimizing the number of base transceivers required for accurate positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the mobile station uses worst-case synchronization accuracy specifications for positioning estimates, then the positioning accuracy becomes sufficiently conservative, but the positioning accuracy becomes overly pessimistic and may require more base transceivers than necessary

Engineering Contradiction:
Improvepositioning accuracyVSAvoidpositioning accuracy estimate
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The mobile station measures its actual synchronization accuracy with each BTS and feeds this information back to the network. The network then uses this feedback to determine the actual positioning accuracy, replacing the overly pessimistic worst-case estimates. This feedback loop enables more accurate positioning accuracy assessment without requiring excessive base transceivers.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the parameter used for positioning accuracy estimation from fixed worst-case specification values to dynamically measured actual synchronization accuracy values. This parameter change allows the system to adapt to real conditions rather than relying on conservative upper bounds, thereby improving measurement precision while maintaining reliability.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the network involves multiple base transceivers in the positioning procedure to ensure sufficient accuracy, then the positioning reliability increases, but the device complexity and number of elements involved increases

Engineering Contradiction:
Improvepositioning accuracyVSAvoidnumber of base transceivers
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of involving all possible base transceivers or using excessive worst-case margins, the patent applies partial action by using only the necessary number of BTSs based on actual measured synchronization accuracy. The system determines the minimum required number of BTSs to achieve target positioning accuracy, avoiding unnecessary complexity from excessive involvement of base transceivers.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent makes the number of base transceivers involved in positioning dynamic rather than static. The system adjusts the number of BTSs based on actual synchronization conditions measured by the mobile station, allowing the positioning procedure to adapt to real-time conditions and minimize the number of elements required while maintaining reliability.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If the mobile station transmits synchronization accuracy information to the BSS, then the positioning accuracy improves, but the loss of time for the positioning procedure increases due to additional signaling

Engineering Contradiction:
Improvepositioning accuracy estimateVSAvoidpositioning procedure time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The mobile station performs synchronization accuracy measurements with neighboring BTSs in advance, before the actual positioning procedure is initiated. This preliminary action ensures that when positioning is needed, the accuracy information is already available, minimizing additional signaling time and allowing the positioning procedure to proceed efficiently with pre-measured data.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3535597B1Providing estimated accuracy of mobile station synchronization to the network
Publication Date: 2020.08.26 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3535597B1 patent drawingFigure 1
  • EP3535597B1 patent drawingFigure 2
  • EP3535597B1 patent drawingFigure 3

AI summary

A mobile station (MS), a base station subsystem (BSS), and various methods are described herein that enable a positioning node (e.g., Serving Mobile Location Center (SMLC)) to improve the accuracy of estimating a position of the mobile station.