NFC Controller SWP Interface Arbitration for Multiple Secure Elements

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Solution Overview

Problem

Current Single Wire Protocol (SWP) standards only allow communication between one contactless element, such as an NFC controller, and one secure element, making it challenging to manage information exchange between multiple auxiliary elements in a mobile phone, which increases design complexity and limits application separation.

Innovation Solution

A method and device that utilize a single SWP interface to connect multiple secure elements to an NFC controller, where only one secure element is active at a time, allowing others to listen and activate based on specific frames, with firmware adaptation to manage multiple SWP interfaces efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple secure elements are connected to a NFC controller using separate interfaces (SWP interface and NFC-WI), then communication with multiple auxiliary elements is enabled, but the design complexity of the NFC controller increases due to managing additional interfaces

Engineering Contradiction:
Improvecommunication capability with multiple secure elementsVSAvoidNFC controller interface complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges multiple secure element connections into a single SWP interface by implementing a master arbitration mechanism. The master SWP interface manages multiple slave secure elements through a unified protocol, eliminating the need for separate NFC-WI interface and reducing interface management complexity while maintaining the ability to communicate with multiple secure elements simultaneously

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If two SWP interfaces are provided in the NFC controller, then communication with multiple SWP-based secure elements is enabled, but the design complexity increases due to managing additional interface

Engineering Contradiction:
Improvecommunication capability with multiple SWP secure elementsVSAvoidNFC controller interface complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent makes a single SWP interface universal by implementing arbitration logic that allows one master SWP interface to serve multiple slave secure elements. The interface can dynamically switch between different secure elements based on arbitration outcomes, providing multi-functionality without requiring multiple physical interfaces, thus reducing design complexity while maintaining versatility

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Device complexity

If only one secure element is connected to the NFC controller via SWP interface, then the interface management is simple, but the capability to support multiple auxiliary elements from different issuers is limited

Engineering Contradiction:
Improveinterface management simplicityVSAvoidsupport for multiple applications from different issuers
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent segments the communication capability at the logical level while maintaining physical interface simplicity. Multiple secure elements are connected to a single SWP interface, and the master arbitration mechanism segments the time-multiplexed access to each secure element. This allows simple interface management at the physical layer while providing extensive support for multiple applications from different issuers through logical segmentation

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2447872B1Method and device for managing information exchange between for example a NFC controller and a set of at least two secure elements.
Publication Date: 2020.03.11 STMICROELECTRONICS (ROUSSET) SAS
  • EP2447872B1 patent drawingFigure 1~2
  • EP2447872B1 patent drawingFigure 3
  • EP2447872B1 patent drawingFigure 4~8

AI summary

The device comprises a contactless element (ME) and a set of at least two auxiliary elements (SEi), each auxiliary element including a slave SWP interface (SLINTi) connected to a same master SWP interface (MINT) of said contactless element (ME) through a SWP link (LK) and management means (MMG, AMGi) configured for activating at once only one slave SWP interface on said SWP link.