Backscatter Tag Synchronization via Ambient Cellular OFDM Pulses

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Solution Overview

Problem

Existing backscatter systems face challenges in achieving low-power, low-cost IoT connections due to the need for additional excitation sources, and there is a lack of effective synchronization and control methods for low-power tags in cellular networks.

Innovation Solution

A method for synchronizing and controlling backscatter communication using ambient cellular OFDM signals, involving the transmission of synchronization and control information, conversion of these signals into digital pulse signals using an envelope-detection circuit, and identifying control information through multi-segment pulse widths, without requiring additional excitation signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional excitation sources are deployed for backscatter communication, then communication reliability is improved, but deployment cost and system complexity increase

Engineering Contradiction:

Improvecommunication reliabilityVSAvoiddeployment complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system uses existing ambient cellular signals to serve as excitation sources for backscatter communication. The cellular base station's downlink signals are naturally reflected by backscatter tags, eliminating the need for dedicated excitation sources. This self-service approach reduces deployment complexity while maintaining communication reliability.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The cellular base station performs multiple functions: it provides both cellular communication services and serves as an excitation source for backscatter communication simultaneously. The downlink signals serve dual purposes, reducing the need for additional dedicated infrastructure.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If correlation-based synchronization is used for received signals, then synchronization accuracy is improved, but computational complexity and power consumption increase

Engineering Contradiction:

Improvesynchronization accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent extracts synchronization information from the envelope of the received OFDM signal rather than performing full correlation-based synchronization. By taking only the essential envelope information and using simple threshold detection, the system achieves sufficient synchronization accuracy while dramatically reducing computational complexity and power consumption for low-power tags.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The system uses simple, low-cost synchronization methods suitable for disposable or low-power tags. Instead of implementing complex correlation algorithms that require significant processing power, the patent employs simple envelope detection and threshold comparison that can be implemented in ultra-low-power circuitry.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Productivity

If CP part is modulated with useful information, then data transmission efficiency is improved, but signal integrity deteriorates due to CP deletion by receiver

Engineering Contradiction:

Improvedata transmission efficiencyVSAvoidsignal integrity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent ensures that the CP portion does not contain modulated information before transmission. By preliminarily preventing information modulation on the CP part, the system avoids the problem of signal integrity deterioration caused by CP deletion at the receiver, while still maintaining efficient data transmission through proper resource allocation.

Inventive Principle:

Principle #10Preliminary action

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 reliable synchronization and control of backscatter tags within a range of 12 meters, applicable to any bandwidth, without the need for additional excitation signals, thus addressing the power and cost issues in current backscatter technologies.

Implementation Method 1

a backscatter technology has emerged as an effective solution for low-power and low-cost IoT technologies

Methodology Applied

Scientific EffectBackscatter: Scattering

Implementation Method 2

utilizing, by the backscatter tag, an envelope-detection circuit to convert the ambient cellular OFDM signal into a digital pulse signal

Methodology Applied

Scientific EffectEnvelope detection:

Data Source

PatentUS20260088946A1Method for synchronizing and controlling backscatter communication based on ambient cellular OFDM signal

Publication Date: 2026.03.26 UNIV OF ELECTRONICS SCI & TECH OF CHINA

AI summary

A method for synchronizing and controlling backscatter communication based on an ambient cellular OFDM signal includes the following steps: S10, transmitting, by a transmitting terminal, an ambient cellular OFDM signal, which carries synchronization and control information; and S20, acquiring, by a backscatter tag, the synchronization and control information from the ambient cellular OFDM signal, including: utilizing, by the backscatter tag, an envelope-detection circuit to convert the ambient cellular OFDM signal into a digital pulse signal; establishing, by the backscatter tag, synchronization with the transmitting terminal by detecting a rising edge of the digital pulse signal; and identifying, by the backscatter tag, the control information of the transmitting terminal by detecting multi-segment pulse widths of the digital pulse signal.