Wireless Network Location Determination Without GPS

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Solution Overview

Problem

Digital telephony devices without integrated GPS positioning systems, such as laptops and desktops, face challenges in determining their location, especially when making emergency calls, as they cannot provide precise location information, which is often required by emergency services.

Innovation Solution

The solution involves obtaining location information for originating stations in a wireless network by using the known location of access points and signal strength from other devices, with techniques like trilateration and clustering to estimate the location of devices lacking positioning equipment, and prompting users for input if accuracy thresholds are not met.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If GPS positioning systems are integrated into digital telephony devices, then location information can be obtained, but device complexity and cost increase

Engineering Contradiction:
Improvelocation information accuracyVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses access points as intermediary devices to determine the location of telephony devices. Instead of requiring GPS in each telephony device, the system employs access points with known locations and signal strength measurements as mediators to calculate the position of calling devices through trilateration or clustering algorithms.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical/GPS-based positioning system with a signal-based positioning system. Instead of using satellite signals and GPS receivers, the system uses wireless signal strength measurements from access points to determine location, substituting one technical approach with another that avoids adding hardware to telephony devices.

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

2Reliability

If location determination methods are implemented for devices without GPS, then emergency call requirements can be met, but system complexity increases

Engineering Contradiction:
Improveemergency call complianceVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements self-service by having access points automatically perform location determination for telephony devices. The access points measure signal strengths, apply clustering algorithms or trilateration calculations, and provide location information without requiring manual configuration or complex processing at the telephony device end.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent uses preliminary action by pre-configuring access point locations and maintaining updated visibility lists of accessible access points. This preparatory work enables rapid location determination during emergency calls without requiring complex real-time processing when the emergency call is placed.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If signal strength measurements from multiple access points are used, then location accuracy improves, but measurement and processing difficulty increases

Engineering Contradiction:
Improvelocation accuracyVSAvoidmeasurement complexity
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies partial action by using a limited set of visible access points for location determination rather than requiring measurements from all possible access points. The system identifies and uses only those access points that are currently visible and accessible to the telephony device, reducing measurement complexity while maintaining sufficient accuracy.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent uses copying by maintaining visibility lists that replicate information about accessible access points. These visibility lists contain pre-collected information about which access points are visible from different locations, allowing the system to quickly determine location without performing complex real-time measurements of all possible access points.

Inventive Principle:
Principle #26Copying

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

This method enables the inclusion of location information in emergency calls, even from devices without GPS, ensuring compliance with emergency call requirements and reducing configuration burdens for wireless networks by approximating locations based on visible access points and signal strengths.

Implementation Method 1

signal strength from other devices, with techniques like trilateration and clustering to estimate the location

Methodology Applied
Scientific EffectSignal strength attenuation:

Data Source

PatentEP4055923B1Distributed location determination in wireless networks
Publication Date: 2024.08.14 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP4055923B1 patent drawingFigure 1
  • EP4055923B1 patent drawingFigure 2
  • EP4055923B1 patent drawingFigure 3

AI summary

In some embodiments, a location of a mobile terminal is determined by obtaining a location of a first access point (AP), receiving a visibility indication indicating that a second AP received a signal from the first AP or the first AP received a signal from the second AP, determining a location of the second AP based on the received visibility indication and the location of the first AP, determining a location of the mobile terminal in communication with the second AP based on the determined location of the second AP, and transmitting a message indicating the location of the mobile terminal on a digital communication network.