Passive Tag Network Access to Cut UE Power and Delay

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Solution Overview

Problem

Performing a random-access procedure in wireless communication systems adds delay and consumes excessive power, particularly in low-power UEs, as they need to proactively transmit preambles on configured time-frequency resources.

Innovation Solution

Utilizing a passive radio frequency ID (RFID) tag powered by RF energy to backscatter a UE ID, eliminating the need for active random-access procedures by using a stimulus signal to modulate the UE ID onto backscatter for network access and data communication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a random-access procedure is performed for network access, then the UE can establish network connection and transmit data, but the UE consumes excessive power and experiences access delay

Engineering Contradiction:

Improvenetwork access capabilityVSAvoidUE power consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

Instead of the UE actively transmitting a preamble to initiate random access, the network side actively transmits a stimulus signal that triggers the passive tag to backscatter the UE ID. This inverts the traditional access initiation direction, allowing the UE to remain in a low-power state while still enabling network access.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

A passive tag is introduced as an intermediary component that the UE carries. This passive tag performs backscatter communication to transmit the UE ID to the network side without consuming UE power, effectively mediating between the power-constrained UE and the network access requirement.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a random-access procedure is performed for network access, then the UE can establish network connection and transmit data, but the network access delay increases

Engineering Contradiction:

Improvenetwork access capabilityVSAvoidnetwork access delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The network side pre-configures stimulus signal resources and maintains readiness to transmit stimulus signals. When a UE needs network access, the stimulus signal can be immediately transmitted and the passive tag can instantly backscatter the UE ID, eliminating the multi-step random access procedure and reducing access delay.

Inventive Principle:

Principle #10Preliminary action

3Ease of operation

If the UE proactively transmits preambles on configured time-frequency resources, then network access can be initiated, but the UE power consumption increases

Engineering Contradiction:

Improvenetwork access initiationVSAvoidUE power consumption

Core Design Contradiction:

Ease of operationVSUse of energy by moving object

Solution Approach 1:

The passive tag serves itself by harvesting RF energy from the stimulus signal transmitted by the network side and using this energy to power the backscatter transmission of the UE ID. This self-service mechanism eliminates the need for the UE to provide power for access signal transmission.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The active transmission mechanism (UE transmitting preambles using its own power amplifier) is replaced with a passive backscatter mechanism (passive tag modulating the stimulus signal). This substitution eliminates the need for complex power amplification and signal generation in the UE, dramatically reducing power consumption.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

The passive tag approach reduces power consumption and delays by replacing random-access procedures, enabling faster and lower power network access with reduced power consumption and potential data transmission.

Implementation Method 1

The tag harvests the energy from the stimulus signal and uses the energy to modulate the UE ID onto the backscatter

Methodology Applied

Scientific EffectRF energy harvesting: Electromagnetic Induction

Implementation Method 2

The passive tag may be used to transmit a UE ID to a TRP for use in network access and/or data communication. For example, a TRP transmits a stimulus signal. The RF energy of the stimulus signal causes the antenna of the passive tag to radiate power, referred to as 'backscatter'.

Methodology Applied

Scientific EffectBackscatter: Reflection

Data Source

PatentUS20260066983A1Wireless network access and data communication using passive tag

Publication Date: 2026.03.05 HUAWEI TECH CO LTD

AI summary

In a wireless communication system, sometimes a network access procedure needs to be performed so that data may be communicated between a user equipment (UE) and a transmit-and-receive point (TRP). One example way to perform network access is to perform a random-access procedure. Performing a random-access procedure adds delay and possibly results in increased power consumption. In some embodiments herein, a UE includes a passive tag, such as a passive RFID tag. The passive tag backscatters a UE ID to the TRP. The TRP may then transmit an indication of the UE ID back to the UE. Data communication may then possibly occur between the TRP and the UE using the UE ID. The procedure may replace a random-access procedure.