SIM Processor Bi-directional Data Link via Software UART

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Solution Overview

Problem

Current SIM processors lack a direct data path due to their restrictive bus structure, necessitating external devices like microprocessors and cell modules for serial data communication, which does not provide a connection to the SIM.

Innovation Solution

A bi-directional data communications link is simulated in software to enable communication between a SIM processor and external devices, using serial connections like UART, USB, or GPIO, allowing for data processing, encryption, and secure data handling within the SIM.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a SIM processor uses a restrictive bus structure for security, then security is improved, but data communication capability deteriorates

Engineering Contradiction:

ImprovesecurityVSAvoiddata communication capability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

A software-based UART simulation layer is introduced as an intermediary between the restrictive SIM bus structure and external communication devices. This virtual communication interface enables serial data communication without requiring changes to the secure hardware bus architecture, allowing the SIM processor to communicate with external devices while maintaining its security constraints.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the need for physical hardware UART circuits with a software-based simulation implementation. Instead of adding complex hardware communication interfaces to the SIM card, the UART functionality is emulated through software layers that run on the SIM processor, substituting mechanical/hardware communication mechanisms with software-based alternatives.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If external devices provide UART connection for serial data communication, then data communication capability is improved, but direct connection to SIM deteriorates

Engineering Contradiction:

Improveserial data communication capabilityVSAvoiddirect connection to SIM

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The SIM processor is enhanced with multi-functionality by implementing a universal software-based communication interface that can handle various serial communication protocols (UART, USB, GPIO) through a unified software layer. This allows the SIM processor to provide direct serial data communication capability while maintaining compatibility with existing external communication devices through standardized interfaces.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS10306463B2Secure data link for subscriber identification module (SIM)-based processor

Publication Date: 2019.05.28 ABLE DEVICE INC

AI summary

The subject matter described herein includes methods, systems, and computer program products for providing a bi-directional data path to a SIM containing an executable program. According to one system, a subscriber identification module (SIM) is provided that includes a memory configured to store one or more executable instructions and a processor configured to execute the one or more executable instructions to generate one or more commands for controlling a device. At the SIM, a bi-directional data communications link, such as a serial communications link to the SIM processor, is simulated in software. The simulated communications link provides for bi-directional data communications between a customer application which is executed on the SIM and an external device which is not executed on the SIM, such as a microprocessor or cell module.