Baseband STK Scheduling for Multiple eSIMs Without Session Interference

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Solution Overview

Problem

The communication between the eUICC and the baseband processor for multiple eSIMs on a wireless device can result in errors due to overlapping STK sessions, leading to interference and process interruptions.

Innovation Solution

Implementing a baseband processor with an STK scheduler to manage and schedule STK sessions externally, monitoring ongoing sessions, and prioritizing or queuing actions to avoid overlap and reduce errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple eSIMs are enabled concurrently on an eUICC, then wireless service accessibility is improved, but STK session interference and error rates increase

Engineering Contradiction:

Improvewireless service accessibilityVSAvoidSTK session error rate

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

An STK scheduler intermediary component is introduced between the eUICC and baseband processor to manage STK sessions. The scheduler receives STK commands from the application layer, determines the active eSIM profile, and routes commands to the appropriate STK session, preventing interference between concurrent eSIMs while maintaining service accessibility.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The STK communication channel is segmented into multiple independent sessions, one for each eSIM profile. Each session is uniquely identified and managed separately through the scheduler, which maintains distinct command queues and state information for each eSIM, eliminating cross-session interference.

Inventive Principle:

Principle #1Segmentation

2Reliability

If an STK scheduler is implemented at the baseband processor, then STK session management reliability is improved, but device complexity increases

Engineering Contradiction:

ImproveSTK session managementVSAvoidbaseband processor complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The STK scheduler is designed as a multi-functional component that handles multiple eSIM profiles, routes commands to different STK sessions, manages command queuing, and maintains session state information. This universal approach consolidates what would otherwise require separate management mechanisms for each eSIM, reducing overall system complexity while improving reliability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The STK scheduler automatically determines which eSIM profile is active based on incoming commands and session state, making routing decisions without external intervention. The scheduler self-manages command queuing, session activation/deactivation, and error handling, reducing the need for complex external control logic.

Inventive Principle:

Principle #25Self-service

Data Source

PatentEP4099739B1SIM toolkit scheduling for multiple enabled esim profiles

Publication Date: 2025.07.02 APPLE INC

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AI summary

This Application sets forth techniques for managing subscriber identity module (SIM) toolkit (STK) scheduling for multiple enabled electronic subscriber identity module (eSIM) profiles on an embedded universal integrated circuit card (eUICC) of a wireless device, including managing multiple STK sessions at a baseband processor external to the eUICC of the wireless device. To forestall STK communication for different eSIMs from interfering with execution of processes associated with the eSIMs, a baseband processor can schedule STK sessions to avoid overlap and reduce opportunities for errors in handling eSIM processes. The baseband processor can prioritize whether to queue commands for a second STK session for a second eSIM until a first STK session for a first eSIM ends or to terminate the first STK session to handle the second STK session.