NFC-B Poll Mode Device Dynamic Slot Discovery

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Solution Overview

Problem

Existing Near Field Communication (NFC) type-B poll mode devices face inefficiencies in discovering multiple listen mode devices due to unnecessary increase in time slots, leading to delayed data transfer, increased power consumption, and non-compliance with NFC Forum Activity Specifications, resulting in unpredictable behavior and interoperability issues.

Innovation Solution

A deterministic discovery method that dynamically adjusts the number of time slots based on detection of empty slots and collisions, ensuring the last discovered device remains active, reducing power consumption, and optimizing hardware/software complexity, while complying with NFC Forum specifications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the number of time slots is increased to ensure all NFC-B listen mode devices are discovered, then the completeness of device discovery is improved, but the data transfer time is delayed and power consumption increases

Engineering Contradiction:
Improvecompleteness of device discoveryVSAvoiddata transfer time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements dynamic adjustment of the number of time slots based on actual discovery needs. The poll mode device monitors collision detection results and empty slot occurrences, then adaptively increases or maintains the time slot count only when necessary, rather than using a fixed large number of slots. This dynamic approach ensures all devices are discovered while minimizing unnecessary time consumption.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs feedback mechanisms where the poll mode device detects collisions and empty slots during the discovery process. Based on this feedback information, the device intelligently determines whether to increase the number of time slots for subsequent discovery cycles. This feedback-driven approach prevents unnecessary expansion of time slots while ensuring complete device discovery.

Inventive Principle:
Principle #23Feedback

2Reliability

If the number of time slots is increased to discover all NFC-B listen mode devices, then the completeness of device discovery is improved, but power consumption is increased

Engineering Contradiction:
Improvecompleteness of device discoveryVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic adjustment of the number of time slots based on actual discovery needs. The poll mode device monitors collision detection results and empty slot occurrences, then adaptively increases or maintains the time slot count only when necessary, rather than using a fixed large number of slots. This dynamic approach ensures all devices are discovered while minimizing unnecessary time consumption.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs feedback mechanisms where the poll mode device detects collisions and empty slots during the discovery process. Based on this feedback information, the device intelligently determines whether to increase the number of time slots for subsequent discovery cycles. This feedback-driven approach prevents unnecessary expansion of time slots while ensuring complete device discovery.

Inventive Principle:
Principle #23Feedback

3Use of energy by moving object

If the last discovered NFC-B listen mode device is placed in sleep mode to save power, then power consumption is reduced, but compliance with NFC Forum Activity Specification is violated and device activation time increases

Engineering Contradiction:
Improvepower consumptionVSAvoidcompliance with specification
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent implements dynamic adjustment of the number of time slots based on actual discovery needs. The poll mode device monitors collision detection results and empty slot occurrences, then adaptively increases or maintains the time slot count only when necessary, rather than using a fixed large number of slots. This dynamic approach ensures all devices are discovered while minimizing unnecessary time consumption.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs feedback mechanisms where the poll mode device detects collisions and empty slots during the discovery process. Based on this feedback information, the device intelligently determines whether to increase the number of time slots for subsequent discovery cycles. This feedback-driven approach prevents unnecessary expansion of time slots while ensuring complete device discovery.

Inventive Principle:
Principle #23Feedback

4Reliability

If multiple discovery cycles are performed to ensure all devices are discovered, then the completeness of device discovery is improved, but the discovery process time is extended

Engineering Contradiction:
Improvecompleteness of device discoveryVSAvoiddiscovery process time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements dynamic adjustment of the number of time slots based on actual discovery needs. The poll mode device monitors collision detection results and empty slot occurrences, then adaptively increases or maintains the time slot count only when necessary, rather than using a fixed large number of slots. This dynamic approach ensures all devices are discovered while minimizing unnecessary time consumption.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs feedback mechanisms where the poll mode device detects collisions and empty slots during the discovery process. Based on this feedback information, the device intelligently determines whether to increase the number of time slots for subsequent discovery cycles. This feedback-driven approach prevents unnecessary expansion of time slots while ensuring complete device discovery.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2942874B1Method for discovering a plurality of NFC-B devices by a NFC-B reader and corresponding NFC-B reader
Publication Date: 2017.01.25 STMICROELECTRONICS INT NV
  • EP2942874B1 patent drawingFigure 1~2
  • EP2942874B1 patent drawingFigure 3
  • EP2942874B1 patent drawingFigure 4a

AI summary

A discovered NFC-B listen mode device is put to SLEEP state only when there are one or more NFC-B listen mode devices yet to be discovered; an optimal value for the number (NoS) of time slots indicated in a command (SENSB_REQ) is computed based on a combination of whether an empty time slot was detected and/or collision was detected and/or an NFC-B listen mode device was discovered in a discovery cycle. The compliance with the NFC Forum Activity Specification allows the direct activation of an NFC-B listen mode device, and thus speeds up the data transfer phase and consumes much less power.