Passive Wireless Device Backscatter Using Communications Signatures

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Solution Overview

Problem

Passive wireless devices experience high levels of interference in wireless communications systems, leading to reduced likelihood of successful decoding of backscattered communications due to overlapping sub-channels and interference from other devices.

Innovation Solution

Implementing configuration- or signaling-based interference avoidance mechanisms, including communications signatures, bandwidth filtering, power control, and sub-channel selection to reduce interference, allowing for successful decoding of backscattered signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If passive wireless devices use backscattered communications to transmit data, then energy efficiency is improved, but interference from overlapping sub-channels increases

Engineering Contradiction:

Improveenergy efficiencyVSAvoidinterference

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent divides the communication spectrum into multiple sub-channels and assigns different sub-channels to different passive wireless devices for backscattered communications. This segmentation reduces interference by ensuring that devices operating on different sub-channels do not overlap in their transmissions, thereby maintaining energy efficiency while reducing interference.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic sub-channel selection and switching mechanisms where passive wireless devices can be assigned different sub-channels based on real-time interference conditions. The system dynamically adjusts which sub-channel each device uses to minimize interference while maintaining successful decoding, resolving the contradiction between energy efficiency and interference.

Inventive Principle:

Principle #15Dynamics

2Productivity

If multiple passive wireless devices operate simultaneously on overlapping sub-channels, then system capacity is improved, but decoding reliability decreases

Engineering Contradiction:

Improvesystem capacityVSAvoiddecoding reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies different communication parameters and sub-channel assignments to different passive wireless devices based on their specific operational conditions. Each device is configured with appropriate sub-channels and transmission parameters tailored to its local environment, enabling multiple devices to operate simultaneously with high reliability by avoiding mutual interference.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent incorporates feedback mechanisms where the reader device receives signals from passive wireless devices and uses this information to adjust sub-channel assignments and transmission parameters. This feedback loop enables the system to maintain high system capacity while ensuring decoding reliability by adapting to changing interference conditions in real-time.

Inventive Principle:

Principle #23Feedback

3Device complexity

If passive wireless devices transmit without interference avoidance mechanisms, then device complexity is reduced, but communication reliability is worsened

Engineering Contradiction:

Improvedevice complexityVSAvoidcommunication reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent introduces an intermediary control mechanism (the reader device or network controller) that manages sub-channel assignments and coordination between passive wireless devices. This intermediary handles the complexity of interference avoidance centrally, allowing the passive devices themselves to remain simple while achieving reliable communication through coordinated operation.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Enhances the reliability of backscattered communications, increasing data rates and system capacity by reducing interference, thereby facilitating the broader adoption of passive wireless devices.

Implementation Method 1

transmitting, to the reader device, a second message via a backscattering of the first message

Methodology Applied

Scientific EffectBackscattering: Scattering

Data Source

PatentUS20250307575A1Interference reduction techniques between passive wireless devices

Publication Date: 2025.10.02 QUALCOMM INC

AI summary

This disclosure provides systems, methods and apparatus, including computer programs encoded on computer storage media, for interference reduction techniques between passive wireless devices. In some aspects, a source device, a reader device, or a passive wireless device may support one or more interference avoidance mechanisms according to which the reader device may experience less interference from other devices within a system or may more accurately decode messaging that is meant for the reader device from the radio frequency signaling received at an antenna of the reader device, or both. In some implementations, multiple passive wireless devices may each add or apply a respective communications signature to a reflected or backscattered signal from that passive wireless device. The respective communications signatures may uniquely identify backscattered signaling from a specific passive wireless device such that a reader device may parse through received signaling and extract and decode a relevant message.