Smart Card Context Data Preservation for Low Power Resume

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Solution Overview

Problem

Battery-powered devices with UICC smart cards face significant power consumption issues during low power states, leading to reduced battery life due to the inefficiencies of existing SUSPEND and RESUME operations, which require significant current draw and processing time, and result in context data loss.

Innovation Solution

A method and device that request and store context data from the UICC, reduce or remove power to the smart card, and later restore power to write the context data back, leveraging the device's processing capabilities for efficient resume operations, thus minimizing power consumption and extending battery life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the UICC is powered down during sleep state to reduce power consumption, then power consumption is significantly reduced, but the device requires significant current draw and time to re-initialize the UICC when power is restored

Engineering Contradiction:

Improvepower consumptionVSAvoidre-initialization time

Core Design Contradiction:

Use of energy by moving objectVSLoss of time

Solution Approach 1:

The device performs preliminary actions by saving context data from the UICC to its own memory before powering down the UICC. When the UICC is powered back up, the device can quickly restore operation using the saved context data, avoiding the need for lengthy re-initialization processes. This preliminary data preservation enables fast resume operations.

Inventive Principle:

Principle #10Preliminary action

2Use of energy by moving object

If the UICC is powered down during sleep state to reduce power consumption, then power consumption is significantly reduced, but the UICC loses its context which impacts running applications

Engineering Contradiction:

Improvepower consumptionVSAvoidcontext data loss

Core Design Contradiction:

Use of energy by moving objectVSLoss of information

Solution Approach 1:

The invention extracts context data from the UICC and stores it in the device's own memory before powering down the UICC. This extraction of essential information allows the UICC to be completely powered down for power savings while the device retains the necessary context data. When the UICC is restored, the context data can be quickly transferred back, preventing information loss.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If the UICC remains powered during low power states to maintain context, then context is preserved, but the UICC consumes non-negligible power (e.g. 15 μA) that accumulates over time

Engineering Contradiction:

Improvecontext preservationVSAvoididle power consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The device creates a copy of the UICC's context data and stores it in its own memory. This copying mechanism allows the original UICC to be completely powered down, eliminating idle power consumption, while the device maintains a local copy of the context data. When the UICC is restored, the copied data enables rapid re-initialization without requiring the UICC to remain powered during sleep states.

Inventive Principle:

Principle #26Copying

Data Source

PatentUS11815975B2Devices with removable smart cards

Publication Date: 2023.11.14 NORDIC SEMICONDUCTOR

AI summary

A method of controlling an electronic device including a memory and a removable smart card. The method involves the device sending a request for context data to the smart card. The smart card sends context data to the device in response to the request and stores this data in the memory and power to the smart card is reduced. Power to the smart card is then increased or restored, and the data is written back to the smart card.