Ambient Backscatter Transceiver Passive RF Modulation

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Solution Overview

Problem

Existing wireless data transmission technologies face challenges in powering small, numerous computing devices embedded in objects and environments, as traditional backscatter communication requires special infrastructure and cannot sense transmissions from other tags, and conventional radio wave generation consumes more power than can be harvested from ambient RF signals.

Innovation Solution

The development of ambient backscatter transceivers that utilize radio frequency (RF) signals to communicate by modulating and demodulating backscattered ambient RF signals, allowing devices to transmit encoded data without the need for special infrastructure and using low-power circuitry to decode and harvest power from ambient RF signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If conventional radio wave generation is used, then data transmission can be achieved, but power consumption exceeds what can be harvested from ambient RF signals

Engineering Contradiction:
Improvepower consumptionVSAvoidtransmitted power
Core Design Contradiction:
Use of energy by moving objectVSPower

Solution Approach 1:

The patent replaces active radio wave generation with passive backscatter modulation. Instead of using power-hungry radio frequency amplifiers to generate signals, the system modulates ambient RF signals by changing the impedance of a backscatter antenna, thereby reflecting signals with embedded data. This substitution of active transmission with passive reflection dramatically reduces power consumption to levels that can be sustained by harvested ambient RF energy.

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

2Use of energy by moving object

If traditional backscatter communication is used, then power consumption is reduced, but special infrastructure (RFID readers) is required

Engineering Contradiction:
Improvepower consumptionVSAvoidinfrastructure requirements
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent enables backscatter transceivers to function both as transmitters and receivers using the same hardware components. The backscatter antenna and impedance modulation circuitry used for transmission can also detect and demodulate signals from other tags. This multi-functionality eliminates the need for separate RFID reader infrastructure, as any tag can serve as both interrogator and respondant, enabling peer-to-peer communication.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of operation

If traditional RFID systems are used, then communication can occur, but tags cannot sense transmissions from other tags

Engineering Contradiction:
Improvecommunication capabilityVSAvoidtransmission sensing capability
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent implements a feedback mechanism where each backscatter transceiver continuously monitors the ambient RF environment for transmissions from other tags. When a transmission is detected, the receiving tag can modulate its backscatter signal to acknowledge receipt or provide responsive data. This feedback capability enables full-duplex communication where tags can both transmit and sense each other's transmissions, creating a mesh network topology.

Inventive Principle:
Principle #23Feedback

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

Enables efficient, low-power wireless communication between devices by leveraging ambient RF signals for both data transmission and power harvesting, allowing devices to operate autonomously and communicate with each other without exclusive infrastructure, improving energy efficiency and scalability.

Implementation Method 1

an antenna configured to receive a backscattered ambient radio frequency (RF) signal

Methodology Applied
Scientific EffectBackscatter: Reflection

Implementation Method 2

a demodulator coupled to the antenna. The demodulator may be configured to demodulate the backscattered ambient RF signal to retrieve first data

Methodology Applied
Scientific EffectDemodulation:

Implementation Method 3

The ambient RF signal may be further modulated to provide second data at a second frequency

Methodology Applied
Scientific EffectElectromagnetic radiation:

Data Source

PatentEP2976734B1Ambient backscatter tranceivers, apparatuses, systems, and methods for communicating using backscatter of ambient RF signals
Publication Date: 2019.09.18 UNIVERSITY OF WASHINGTON THROUGH ITS CENTER FOR COMMERCIALIZATION
  • EP2976734B1 patent drawingFigure 1
  • EP2976734B1 patent drawingFigure 2
  • EP2976734B1 patent drawingFigure 3

AI summary

Apparatuses, systems, ambient backscatter transceivers, and methods for modulating a backscatter of an ambient RF signal are described. An example system may include an ambient backscatter transceiver comprising an antenna that is configured to receive a backscattered ambient radio frequency (RF) signal. The ambient backscatter transceiver is configured to demodulate the backscattered ambient RF signal to retrieve first data. The backscattered ambient RF signal is generated by backscattering an ambient RF signal at a first frequency. The ambient RF signal is encoded with modulated to provide second data at a second frequency.