NFC Power State Rejection via Magnetic Field Delay

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Solution Overview

Problem

Mobile devices equipped with Near Field Communication (NFC) technology face issues with entering an inactive mode due to false detection of magnetic fields, leading to unnecessary power consumption and interference with NFC transactions.

Innovation Solution

Incorporating a sensor to detect magnetic fields and a delay mechanism to verify NFC transactions, preventing the device from entering a low power state if an NFC transaction is detected during the delay period, and allowing entry into a low power state if no transaction is detected.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the device enters a low power state upon detecting a magnetic field, then battery life is extended, but NFC transaction processing may be interrupted or failed

Engineering Contradiction:
Improvebattery lifeVSAvoidNFC transaction processing
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The system performs preliminary detection of NFC fields before transitioning to low power state. The NFC detector checks for active NFC transactions in advance, and only allows power state transition when no NFC activity is detected, preventing interruptions to ongoing transactions

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from the NFC detector to control the power state transition. The power controller continuously monitors NFC transaction status and adjusts power state accordingly, maintaining reliability while enabling power savings when appropriate

Inventive Principle:
Principle #23Feedback

2Use of energy by moving object

If the device uses a sensor to detect magnetic fields for cover detection, then power consumption is reduced when device is in cover, but false detection may occur during NFC transactions

Engineering Contradiction:
Improvepower consumptionVSAvoidmagnetic field detection accuracy
Core Design Contradiction:
Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The NFC detector acts as an intermediary between the magnetic field sensor and the power control system. It mediates the detection process by filtering out false magnetic field signals that occur during NFC transactions, allowing accurate distinction between cover detection and NFC activity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system combines multiple detection mechanisms (magnetic field sensor and NFC detector) into a composite detection system. This composite approach allows the device to cross-validate signals and distinguish between genuine cover detection events and magnetic field interference during NFC transactions

Inventive Principle:
Principle #40Composite materials

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

Prevents unnecessary power consumption and ensures continuous operation during NFC transactions by accurately distinguishing between cover detection and NFC activity, maintaining device functionality and battery life.

Implementation Method 1

a sensor operable to sense presence of a magnetic field

Methodology Applied
Scientific EffectMagnetic field sensing: Hall Effect

Implementation Method 2

an NFC detector operable to detect processing of an NFC transaction by the device

Methodology Applied
Scientific EffectNear Field Communication electromagnetic field detection: Electromagnetic Induction

Data Source

PatentEP2725851B1System and method of rejecting a low power state based on a cover detection by a mobile wireless communication device
Publication Date: 2018.07.25 BLACKBERRY LTD
  • EP2725851B1 patent drawingFigure 1
  • EP2725851B1 patent drawingFigure 2~3
  • EP2725851B1 patent drawingFigure 4

AI summary

Apparatus, system and method for rejecting entry to a power saving mode based on a cover detection by an NFC enabled mobile device when an NFC field has been detected, such as from a second NFC enabled device. The apparatus, system and method may include detecting a magnetic field indicating proximity of the mobile device to a cover, determining when a predetermined delay has elapsed, checking the state of a flag that is set when an NFC field is detected, and preventing putting the mobile device into a low power state based on the cover indication if the flag is set.