Cellular CIR Fingerprinting for Accurate Indoor Device Location

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing GNSS technologies face limitations in challenging environments such as buildings and urban canyons, and cellular signal-based localization techniques suffer from accuracy issues, power consumption, privacy concerns, and signal availability, making precise device location determination difficult.

Innovation Solution

Utilizing cellular signal characteristics, particularly channel impulse responses (CIRs), to generate location fingerprints that are time-synchronized and compared to a fingerprint map for accurate device location determination, reducing the need for device-to-tower communication and minimizing power expenditure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cellular signal-based localization techniques are used, then device location can be determined in GNSS-challenged environments, but accuracy is limited due to imprecise timing and synchronization

Engineering Contradiction:

Improvelocation determination capability in challenging environmentsVSAvoidlocation accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The system performs preliminary time synchronization and calibration of cellular signals before using them for location determination. By pre-synchronizing multiple cellular nodes and establishing reference timing relationships in advance, the system compensates for inherent timing imprecision in cellular networks, thereby improving location accuracy without requiring complex real-time corrections

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary reference signal or synchronization mechanism that mediates between multiple cellular nodes and the localization system. This intermediary element facilitates precise timing alignment and signal coordination, enabling accurate multi-node signal integration for location determination while overcoming individual node timing limitations

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If user-centric cellular signal transmission to cell towers is used for localization, then positioning information can be obtained, but power is expended and privacy concerns arise

Engineering Contradiction:

Improvepositioning informationVSAvoiddevice power consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

Instead of having the user device transmit signals to cell towers (user-centric approach), the system inverts the approach by having cellular nodes transmit reference signals to the user device. The device then passively receives and processes these downlink signals for location determination, dramatically reducing power consumption while eliminating the need for device-to-tower uplink transmission

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The cellular network infrastructure autonomously provides the localization service by transmitting reference signals and processing measurements without requiring active participation or signal transmission from the user device. The device simply receives and processes the signals, making the system energy-efficient and privacy-preserving

Inventive Principle:

Principle #25Self-service

3Ease of manufacture

If cellular signals are used for localization, then zero-deployment costs and ubiquity are achieved, but signal availability and coverage are limited

Engineering Contradiction:

Improvedeployment costVSAvoidsignal availability

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The system leverages the multi-functionality of cellular signals by utilizing existing commercial cellular infrastructure for both communication and localization purposes. By extracting multiple signal characteristics (timing, frequency, power, phase) from standard cellular transmissions, the system achieves broad geographic coverage and signal availability without requiring dedicated localization infrastructure, thereby maintaining zero deployment cost while enhancing adaptability

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS20260043889A1Utilizing cellular signals for determining device location

Publication Date: 2026.02.12 GOOGLE LLC

AI summary

Implementations relate to utilizing cellular signals to determine device location. In some implementations, a method includes obtaining location fingerprints, each fingerprint associated with a respective geographic location and being based on cellular signal characteristics at that location including multiple channel impulse responses (CIRs) for each location fingerprint for signals received from a plurality of cellular nodes. A fingerprint map is formed that references the location fingerprints. A request may be received for a particular geographic location of a particular user device, and a particular location fingerprint is obtained for the particular device that indicates cellular signal characteristics at the particular location, including CIRs for signals received from multiple cellular nodes. The particular fingerprint is compared to location fingerprints in the fingerprint map, a matching location fingerprint in the fingerprint map is selected, and an associated geographic location is output as the particular location of the particular device.