RF Communication Control System False Alarm Reduction

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Solution Overview

Problem

Conventional Low Power Card Detection (LPCD) algorithms in RF communication devices, such as NFC and RFID systems, often trigger false alarms due to disturbances from adjacent radio activity and temperature changes, leading to increased power consumption and reduced detection range.

Innovation Solution

A control system for RF communication devices that employs a detector to initiate a wake-up of the communication controller only if the load difference exceeds a high threshold, and performs a presence verification if the difference is between a low and high threshold, thereby distinguishing between actual load changes and disturbances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If conventional LPCD algorithms use short RF sense pulses to detect load changes, then battery lifetime is extended and device availability is improved, but false alarms increase due to disturbances from adjacent radio activity and temperature changes

Engineering Contradiction:
Improvebattery lifetimeVSAvoiddetection accuracy
Core Design Contradiction:
Duration of action of moving objectVSReliability

Solution Approach 1:

The detection process is segmented into multiple stages: initial load change detection, presence verification with additional RF pulses, and confirmation before wake-up. This segmentation allows the system to filter false alarms while maintaining low power consumption by not immediately responding to every detected load change.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Before the communication controller is woken up, a presence verification step is performed using additional RF sense pulses to confirm the detected load change is due to an actual communication counterpart and not a disturbance. This preliminary verification action prevents false alarms while maintaining the low-power detection approach.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If the detector triggers wake-up on any load change above a threshold, then detection sensitivity is maximized, but power consumption increases due to false alarms

Engineering Contradiction:
Improvedetection sensitivityVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts its response based on the magnitude of load change. Small load changes trigger presence verification, while larger changes may trigger immediate wake-up. This dynamic approach maintains high detection sensitivity for actual counterparts while reducing power consumption by avoiding unnecessary wake-ups for false alarms.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses feedback from multiple RF sense pulse measurements to verify the validity of a detected load change before triggering wake-up. This feedback mechanism allows the system to maintain high detection sensitivity while filtering out false alarms that would otherwise increase power consumption.

Inventive Principle:
Principle #23Feedback

3Reliability

If the detector performs presence verification for all load changes between low and high thresholds, then false alarms are reduced, but detection time increases

Engineering Contradiction:
Improvefalse alarm reductionVSAvoiddetection time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system applies partial verification action only when needed - specifically when load changes fall between the low and high thresholds. For larger load changes above the high threshold, the system can proceed with wake-up more quickly. This partial verification approach reduces false alarms while minimizing detection time delays.

Inventive Principle:
Principle #16Partial or excessive 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

This approach prevents false alarms while maintaining high detection sensitivity, reducing power consumption, and extending battery life in battery-powered devices.

Implementation Method 1

a detector (e.g. an LPCD detector) configured to detect the presence of an external communication device by detecting a first load on an RF interface of the RF communication device, said first load resulting from a first transmitted RF pulse

Methodology Applied
Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Data Source

PatentEP3681103B1Control system for a radio frequency communication device
Publication Date: 2021.10.06 NXP BV
  • EP3681103B1 patent drawingFigure 1
  • EP3681103B1 patent drawingFigure 2
  • EP3681103B1 patent drawingFigure 3~4

AI summary

In accordance with a first aspect of the present disclosure, a control system for a radio frequency (RF) communication device is provided, the system comprising: a communication controller configured to control an RF communication of the RF communication device; a detector configured to detect the presence of an external communication device and to initiate a wake-up of the communication controller in dependence on said presence; wherein the detector is configured to detect said presence by detecting a first load on an RF interface of the RF communication device, said first load resulting from a first transmitted RF pulse; and wherein the detector is configured to initiate said wake-up if a difference between the first load and a reference load is above a high threshold, and to perform a presence verification if the difference between the first load and the reference load is between a low threshold and the high threshold. In accordance with further aspects of the present disclosure, a corresponding method for controlling a radio frequency (RF) communication device is conceived, and a corresponding computer program is provided.