SIM Signal Multiplexer for Seamless Dual Baseband Switching

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Solution Overview

Problem

In multi-SIM mobile wireless products with multiple modems, efficient and seamless switching between SIM cards and modems is challenging, particularly during active data transmissions, as existing systems require user interaction and may cause data corruption due to accidental switching.

Innovation Solution

A subscriber identity module (SIM) signal multiplexer is used to seamlessly switch exclusive ownership of SIM cards between basebands without user interaction, ensuring SIMs are not deactivated during the process by latching SIM signals and rerouting them when in a stable clock stop mode, thus preventing data corruption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a multiplexer switches SIM data-paths between various SIM cards and modems dynamically, then SIM allocation flexibility is improved, but risk of data corruption during active transmission increases

Engineering Contradiction:

ImproveSIM allocation flexibilityVSAvoiddata transmission reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The system checks the state of SIM cards and modems before switching data-paths. The multiplexer controller verifies that no active data transmission is ongoing before allowing a switch, preventing data corruption by ensuring the SIM is in a safe state for reassignment

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors the transmission state of each SIM card and modem combination. This feedback mechanism allows the multiplexer controller to make informed decisions about when switching is safe, balancing flexibility with data integrity

Inventive Principle:

Principle #23Feedback

2Reliability

If static allocation of SIM cards to modems is used, then data transmission reliability is improved, but SIM allocation flexibility deteriorates

Engineering Contradiction:

Improvedata transmission reliabilityVSAvoidSIM allocation flexibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system transitions from static to dynamic SIM allocation with conditional switching. The multiplexer can change SIM-to-modem assignments in real-time based on system state, providing both reliability (when switching is safe) and flexibility (when dynamic reassignment is needed)

Inventive Principle:

Principle #15Dynamics

3Speed

If SIM switching is allowed during active data transmission, then switching speed is improved, but data corruption risk increases

Engineering Contradiction:

Improveswitching speedVSAvoiddata corruption risk

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

Before executing a SIM switch, the system performs preliminary checks to ensure no active transmission is in progress. This prevents data corruption by only allowing switches when the SIM is in a safe state, while still enabling rapid reassignment when conditions permit

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9615232B2Subscriber identity module data routing devices, methods for routing subscriber identity module data, control circuits, and methods for controlling a change of a routing

Publication Date: 2017.04.04 APPLE INC

AI summary

A subscriber identity module data routing device is described comprising: a routing circuit configured to provide a routing of input data to a plurality of subscriber identity modules; a routing change feasibility determination circuit configured to determine based on the input data whether a change of the routing is feasible, in response to receiving a request for the change of the routing; and wherein the routing circuit is further configured to change the routing if the routing change feasibility determination circuit determines that the change of the routing is feasible.