Multi-Modem Emergency Call Selection by Latency and Signal Quality

Solution Overview

Problem

In communication devices with multiple SIMs, emergency calls often experience delays and poor voice quality due to repeated attempts on primary and secondary SIMs, especially when the primary SIM is out of coverage or overloaded, leading to potential call drops.

Innovation Solution

A method that sends an Emergency Call Establishment Request to all modems, evaluates signal quality feedback, and selects the modem with the best latency and signal quality for emergency calls, aborting procedures on other modems to ensure reliable and low-latency connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the emergency call is established on the primary SIM, then the call can be placed using the default subscriber identity, but the call may suffer from unacceptable voice quality or being dropped due to overloaded network or low signal quality

Engineering Contradiction:

Improveemergency call establishmentVSAvoidvoice quality and call stability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The system performs preliminary actions by initiating emergency call establishment procedures on multiple SIMs simultaneously before selecting the best connection. This allows the device to proactively evaluate available networks and their signal qualities in advance, rather than sequentially trying each SIM after failure, thereby ensuring reliable connection from the start.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically selects which SIM to use for the emergency call based on real-time signal quality measurements and network conditions. Instead of statically relying on the primary SIM, the device adapts its choice of subscriber identity module based on current environmental factors, optimizing both ease of operation and reliability.

Inventive Principle:

Principle #15Dynamics

2Ease of operation

If the Multiple SIM phone tries to establish the emergency call on the primary SIM first, then the establishment process follows a predefined prioritization order, but the emergency call establishment is delayed for every non successful attempt

Engineering Contradiction:

Improveemergency call establishmentVSAvoidemergency call establishment delay

Core Design Contradiction:

Ease of operationVSLoss of time

Solution Approach 1:

The system performs preliminary actions by initiating emergency call establishment procedures on multiple SIMs simultaneously before selecting the best connection. This allows the device to proactively evaluate available networks and their signal qualities in advance, rather than sequentially trying each SIM after failure, thereby ensuring reliable connection from the start.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system maintains continuous useful action by keeping multiple emergency call establishment procedures running in parallel across different SIMs. Instead of pausing to evaluate which SIM to try next, the device continuously attempts connections on multiple networks simultaneously, eliminating idle time and reducing overall establishment delay.

Inventive Principle:

Principle #20Continuity of useful action

3Reliability

If the emergency call is placed on the primary SIM when the network is overloaded or signal quality is low, then the call may be dropped due to deteriorating signal levels, but avoiding the primary SIM requires evaluating multiple SIMs which complicates the establishment process

Engineering Contradiction:

Improvecall connection stabilityVSAvoidemergency call establishment process

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system performs preliminary actions by initiating emergency call establishment procedures on multiple SIMs simultaneously before selecting the best connection. This allows the device to proactively evaluate available networks and their signal qualities in advance, rather than sequentially trying each SIM after failure, thereby ensuring reliable connection from the start.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses feedback mechanisms by measuring signal quality and network conditions for each available SIM, then using this information to select the optimal modem for the emergency call. The feedback loop continuously monitors connection quality and can trigger modem switching if conditions deteriorate, ensuring reliable connection stability without requiring complex manual evaluation.

Inventive Principle:

Principle #23Feedback

Data Source

PatentEP2888919B1Method for establishment of an emergency call

Publication Date: 2018.06.20 HUAWEI TECH CO LTD

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AI summary

The present invention relates to a method in a communication device for establishment of an emergency call, said communication device being arranged to communicate within communication networks by means of communication modems; the method comprising the steps of: sending an Emergency Call Establishment Request, ECER, to modems (M 1 , M 2 ,..., M N ) of said communication device upon receiving an emergency call initiation signal; receiving at least one ECER feedback signal from each modem, the ECER feedback signal indicating at least one of a latency and/or a signal quality for a communication link associated with each modem; and selecting one modem M n among said modems for an emergency call based on the ECER feedback signals from said modems. Furthermore, the invention also relates to a corresponding communication device, a computer program, and a computer program product thereof.