Backscatter Signal Positioning for Indoor Wireless Accuracy

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Solution Overview

Problem

Existing wireless positioning systems, such as GPS, suffer from low accuracy in urban and indoor environments due to signal blockages and multipath propagation, and active transmission methods are energy-inefficient and costly for asset tracking.

Innovation Solution

A backscatter communication system using frequency-shifted signals from multiple backscatter nodes is employed for UE positioning, where each node is identifiable by a specific frequency offset, enabling phase and frequency information to be determined and used by a positioning control entity or the UE to calculate its location.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If GPS or active transmission methods are used for positioning, then positioning functionality is provided, but positioning accuracy deteriorates in urban and indoor environments due to signal blockages and multipath propagation

Engineering Contradiction:

Improvepositioning accuracyVSAvoidsignal reception reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent introduces backscatter nodes as intermediary devices that reflect positioning signals between the user equipment and network nodes. These nodes act as mediators that relay signals through environments where direct signal paths are blocked, enabling positioning in urban canyons and indoor locations where traditional GPS fails due to signal blockages and multipath effects

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces active transmission mechanisms with passive backscatter reflection. Instead of using active transmitters that require power consumption and complex hardware, the system uses passive backscatter nodes that reflect existing wireless signals, substituting the mechanical/electrical transmission system with an optical/electromagnetic reflection-based system that works effectively in signal-challenged environments

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If active transmission methods are used for positioning, then positioning data can be obtained, but energy consumption increases and device costs rise

Engineering Contradiction:

Improvepositioning capabilityVSAvoidenergy consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The backscatter nodes utilize existing ambient wireless signals (such as cellular or Wi-Fi signals) to perform their positioning function without requiring dedicated power sources or active transmission. The nodes harvest energy and information from the surrounding electromagnetic environment, enabling passive operation that dramatically reduces energy consumption compared to active transmission methods while maintaining positioning capability

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The backscatter nodes serve multiple functions: they act as positioning beacons, reflect communication signals, and can potentially provide other wireless services simultaneously. This multi-functionality allows a single passive device to replace multiple active components, reducing overall system energy consumption and device costs while maintaining comprehensive positioning capability

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 approach enhances indoor positioning accuracy and reduces energy consumption and device costs by leveraging ambient wireless signals for low-power communication, suitable for asset tracking in environments where GPS is ineffective.

Implementation Method 1

each of the plurality of backscatter nodes is identifiable by a backscatter node-specific frequency offset of the frequency-shifted signals

Methodology Applied

Scientific EffectFrequency shift: Doppler Effect

Implementation Method 2

frequency-shifted signals from a plurality of backscatter nodes

Methodology Applied

Scientific EffectBackscatter: Reflection

Data Source

PatentUS12543020B2Use of backscatter signals for positioning within wireless networks

Publication Date: 2026.02.03 NOKIA TECHNOLOGIES OY

AI summary

A method includes controlling receiving, by a user device, frequency-shifted signals from a plurality of backscatter nodes for locating the user device, wherein each of the plurality of backscatter nodes is identifiable by a backscatter node-specific frequency offset of the frequency-shifted signals according to a configuration; determining, by the user device, phase information and a frequency offset for each of the received frequency-shifted signals; and controlling transmitting, by the user device to a network node that provides the configuration: the phase information and the frequency offset for each of the received frequency-shifted signals, for a positioning control entity to carry out the locating of the user device; or a location of the user device that is determined, by the user device, based on the phase information, the frequency offset for each of the received frequency-shifted signals and locations of the plurality of backscatter nodes known by the user device.