Wireless Power Path Identification Using Time-Reversed Multipath Signals

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Solution Overview

Problem

Current wireless charging technologies face challenges in efficiently delivering power over larger distances due to the need for precise location determination and signal transmission path computation in dynamic environments, which is complex and power-consuming.

Innovation Solution

The use of time reversal techniques based on arrival time diversity allows for coherent transmission signal generation and delivery by reversing the arrival times of incoming signals at an antenna array, enabling efficient power transmission without direct time of arrival measurements and reducing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If wireless power transmission is performed at larger distances using sophisticated signal transmitting and receiving components, then power transmission capability is improved, but system complexity and power consumption increase

Engineering Contradiction:
Improvewireless power transmission capabilityVSAvoidsystem complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent applies time reversal technique by inverting the received signal waveform and transmitting it back to the original source. This inversion causes the signal to automatically compensate for multipath propagation effects and arrive back at the transmitter location with coherent combining, enabling simple retrodirective beamforming without complex phase and amplitude control circuits.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The system uses the client device's own transmitted signal as the reference for beamforming. The transmitter captures the signal, applies time reversal, and retransmits it, allowing the system to self-adjust to multipath conditions without requiring complex external calibration or control mechanisms.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If precise location determination and signal transmission path computation are performed in dynamic environments, then transmission accuracy is improved, but computational complexity and power consumption increase

Engineering Contradiction:
Improvelocation determination accuracyVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system uses the client device's own transmitted signal as the reference for beamforming. The transmitter captures the signal, applies time reversal, and retransmits it, allowing the system to self-adjust to multipath conditions without requiring complex external calibration or control mechanisms.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent changes the temporal parameter of the signal by applying time reversal to the received waveform. This parameter transformation automatically compensates for propagation delays and multipath effects, achieving precise signal focusing without complex computational algorithms for location determination.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If time reversal techniques are used to compensate for multipath propagation delays, then signal coherence is improved, but signal processing complexity increases

Engineering Contradiction:
Improvesignal coherenceVSAvoidsignal processing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies time reversal technique by inverting the received signal waveform and transmitting it back to the original source. This inversion causes the signal to automatically compensate for multipath propagation effects and arrive back at the transmitter location with coherent combining, enabling simple retrodirective beamforming without complex phase and amplitude control circuits.

Inventive Principle:
Principle #13The other way round (Inversion)

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 effectively compensates for multipath propagation delays, ensuring that signals arrive at the destination simultaneously, thereby enhancing the efficiency and reliability of wireless power transmission while reducing power consumption.

Implementation Method 1

the signal transmitted from the client device may take multiple paths and thus arrive at the array of antennas at different times

Methodology Applied
Scientific EffectMultipath propagation:

Implementation Method 2

generating a coherent transmission signal by transmitting signals which are time reversed versions of the incoming signals at each antenna

Methodology Applied
Scientific EffectTime reversal:

Data Source

PatentEP4131724B1Transmission path identification based on propagation channel diversity
Publication Date: 2024.05.22 OSSIA INC
  • EP4131724B1 patent drawingFigure 1
  • EP4131724B1 patent drawingFigure 2
  • EP4131724B1 patent drawingFigure 3

AI summary

Various embodiments of the present technology relate generally to wireless power systems. More specifically, some embodiments relate to the use of time reversal techniques utilizing time diversity (e.g., different multipath arrivals at the same antenna) to achieve coherency from the same transmission node. For example, instead of initiating outgoing transmissions (e.g., power signals) at the same time, various embodiments can initiate the outgoing signals from the various antennas in a staggered timing that is a reversal of the arrival times of an incoming signal. As a result of staggering the start of the outgoing signals, the signals will arrive at the destination at approximately the same time even though they have traveled different paths having different propagation delays.