AMP Wi‑Fi Triggered Uplink Without Spoofing Preamble

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Solution Overview

Problem

The IEEE 802.11 protocol is not applicable to ambient power (AMP) Internet of Things (IoT) devices that do not have power or have low power, limiting communication capabilities for battery-less or low-power devices such as RFID devices.

Innovation Solution

Methods for communication between an AMP access point (AP) and non-AP station (STA) involving the transmission of a downlink physical layer protocol data unit (PPDU) with a spoofing preamble and trigger frame, followed by a trigger-based uplink PPDU transmission without a spoofing preamble, utilizing on-off keying (OOK) format and specific synchronization patterns in the PHY headers to facilitate communication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the IEEE 802.11 protocol is applied to AMP IoT devices, then communication capability is improved, but power consumption increases making it unsuitable for battery-less or low-power devices

Engineering Contradiction:

Improvecommunication capabilityVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent segments the communication protocol into two distinct modes: active transmission mode for devices with power supply, and backscattering mode for battery-less devices. This segmentation allows each device type to use only the transmission method appropriate for its power capabilities, enabling IEEE 802.11 communication while preventing unnecessary power consumption in AMP devices.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the transmission parameter based on device type: AMP devices use backscattering technique where the modulation depth is controlled by changing the reflection coefficient of the radio frequency signal, while non-AMP devices use conventional active transmission. This parameter change enables communication capability while adapting power consumption to device capabilities.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If spoofing preamble is transmitted in every PPDU, then synchronization is improved, but collision probability increases

Engineering Contradiction:

ImprovesynchronizationVSAvoidcollision probability

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by making the spoofing preamble optional rather than universal. Specifically, spoofing preambles are transmitted only in downlink PPDUs from the access point, while uplink PPDUs from stations omit the spoofing preamble. This localized application of spoofing preambles maintains synchronization where needed (downlink) while reducing collision probability (uplink).

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent inverts the conventional approach by having the access point transmit spoofing preambles in downlink while stations transmit without spoofing preambles in uplink. This inversion resolves the contradiction by placing spoofing preambles only in directions where they provide synchronization benefit without causing collisions.

Inventive Principle:

Principle #13The other way round (Inversion)

3Adaptability or versatility

If AMP devices support both active transmission and backscattering modes, then versatility is improved, but device complexity increases

Engineering Contradiction:

Improvetransmission mode flexibilityVSAvoiddevice complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements dynamics by enabling AMP devices to dynamically switch between backscattering mode and active transmission mode based on their power availability and communication requirements. The device can adapt its transmission mode in real-time, providing versatility while managing complexity through conditional operation rather than permanent dual-capability hardware.

Inventive Principle:

Principle #15Dynamics

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 effective communication with AMP IoT devices by reducing collisions and power consumption, allowing active transmission and backscattering-type STAs to operate efficiently within the IEEE 802.11 framework.

Implementation Method 1

a type of the AMP non-AP STA is a backscattering-type AMP non-AP STA capable of receiving only a DL PPDU and modulating a received DL PPDU signal by varying a reflection coefficient to generate an UL PPDU signal

Methodology Applied

Scientific EffectBackscattering:

Data Source

PatentEP4648259A1Methods for performing communications between ambiment power access point and ambiment power non-access point station

Publication Date: 2025.11.12 MEDIATEK INC

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AI summary

A method for performing communications between an ambient power (AMP) access point (AP) (100, 200) and an AMP non-AP station (STA) (100, 200) includes: transmitting, by the AMP AP, a downlink (DL) physical layer protocol data unit (PPDU) to the AMP non-AP STA, wherein the DL PPDU comprises a spoofing preamble (600) and a trigger frame (308) for triggering the AMP non-AP STA to perform a trigger-based (TB) uplink (UL) PPDU transmission; and receiving, by the AMP AP, a TB UL PPDU without any spoofing preamble from the AMP non-AP STA.