iSIM Modem Shared Memory Access

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Solution Overview

Problem

Current Narrowband Internet of Things devices require a separate Universal Integrated Circuit Card (UICC) for identity verification and key exchange, leading to high power consumption, processing time, and additional system costs due to the need for a separate secure hardware element.

Innovation Solution

Integration of the UICC with the modem chip, where the iSIM file system is stored in a shared memory block accessible by the modem without waking up the iSIM, reducing power consumption and processing time, and implementing a hardware protection block for secure access.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate UICC chip is used for identity verification, then security is maintained, but system costs and device complexity increase

Engineering Contradiction:
ImprovesecurityVSAvoidsystem costs
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the UICC functionality with the modem chip by implementing a shared memory block that stores iSIM profile information accessible by both the modem and iSIM. This integration eliminates the need for a completely separate UICC chip while maintaining security through controlled access mechanisms and hardware protection blocks.

Inventive Principle:
Principle #5Merging (Combining)

2Loss of time

If the iSIM is always powered on to allow direct access, then processing time is reduced, but power consumption increases

Engineering Contradiction:
Improveprocessing timeVSAvoidpower consumption
Core Design Contradiction:
Loss of timeVSUse of energy by moving object

Solution Approach 1:

The patent segments the iSIM memory into a shared memory block for profile information and a separate secure memory block for sensitive data. The shared memory block can be accessed directly by the modem without waking up the iSIM, reducing processing time for non-sensitive operations, while the iSIM remains dormant to conserve power.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The shared memory block acts as an intermediary between the modem and iSIM, allowing the modem to access profile information without direct communication with the iSIM. This eliminates the need to wake up the iSIM for routine profile access, reducing both processing time and power consumption.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If profile information is stored in shared memory accessible by modem, then communication overhead is reduced, but security risks increase

Engineering Contradiction:
Improvecommunication efficiencyVSAvoidsecurity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent divides the memory into shared and secure segments. Profile information that can be openly accessed (IMSI, access class, PLMN lists) is stored in the shared memory block, while sensitive information (operator-key, secret-key) remains in secure memory accessible only by the iSIM. This segmentation enables efficient communication for non-sensitive data while maintaining security for critical authentication credentials.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3694242B1Method and user equipement with an integrated subscriber identity module (ISIM) for sharing a isim file system with a modem
Publication Date: 2023.07.26 SHENZHEN GOODIX TECH CO LTD
  • EP3694242B1 patent drawingFigure 1~2

AI summary

The invention discloses an improved Narrowband Internet of Things device (UE) comprising a modem and an integrated Subscriber Identity Module (iSIM), both combined on a modem chip. The object of the invention to further reduce the cost per UE and to reduce the power consumption of an integrated UICC chip and the processing time will be solved therein that the modem and the iSIM share a common memory block on the modem chip and the modem accesses data comprising a SIM file system with the iSIM profile which is stored in the shared memory block without waking-up the iSIM. The object is also solved by a memory block on the modem chip, which is shared by the modem and the iSIM, whereas a SIM file system with the iSIM profile is stored in the memory block.