Multi-mode Device Emergency Call Network Selection

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Solution Overview

Problem

Multi-mode wireless communication devices face challenges in selecting the appropriate access network for emergency calls, as not all available networks support emergency calls, leading to potential call drops or poor quality service due to the trial-and-error process, which increases the time required to establish an emergency call.

Innovation Solution

The system provides emergency support information from the core network to the device indicating which access networks support emergency calls, allowing the device to intelligently select a suitable network before initiating an emergency call, thereby reducing delays and ensuring satisfactory quality of service.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a multi-mode device attempts to initiate an emergency call over an access network, then the device can attempt to establish emergency communication, but the call may be dropped or experience poor quality of service if the access network does not support emergency calls

Engineering Contradiction:
Improveemergency call establishment reliabilityVSAvoidtime to establish emergency call
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by having the device obtain emergency support information from the core network before initiating an emergency call. This information indicates which access networks support emergency calls, allowing the device to pre-select an appropriate network and avoid the trial-and-error process, thereby resolving the contradiction between call reliability and establishment time

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses emergency support information as an intermediary between the device and the access networks. This information acts as a mediator that guides the device to select only those access networks that support emergency calls, eliminating the need for failed call attempts and redirecting the device away from incompatible networks

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a multi-mode device tries multiple access networks to find one that supports emergency calls, then the device may eventually establish a call, but the trial and error process adds considerable delay

Engineering Contradiction:
Improveemergency call establishment successVSAvoiddelay in placing emergency call
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent eliminates the trial-and-error process by performing preliminary action: the device obtains emergency support information indicating which access networks support emergency calls before attempting to place an emergency call. This allows the device to directly select a suitable network without needing to try multiple networks, thereby resolving the contradiction between call establishment success and time delay

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by having the core network provide emergency support information to the device. This feedback mechanism informs the device about which access networks are capable of supporting emergency calls, enabling the device to make an informed selection and avoid networks that would result in call failure or redirection

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2454895B1Network-assisted initiation of emergency calls from a multi-mode wireless communication device
Publication Date: 2017.08.09 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP2454895B1 patent drawingFigure 1
  • EP2454895B1 patent drawingFigure 2~3
  • EP2454895B1 patent drawingFigure 4A

AI summary

A multi-mode wireless communication device is configured to access a core network of a wireless communication system via any one of multiple different access networks (ANs). Not all of these ANs may support emergency calls. To help the device select which AN it should use to initiate an emergency call, one or more servers in the core network send emergency support information to the device indicating which ANs support emergency calls. The server(s) advantageously send this information to the device prior to the device initiating an emergency call. Thus, upon receiving a command to initiate an emergency call, the device intelligently selects the AN over which to initiate the call based on which ANs actually support that emergency call. This eliminates or at least minimizes the possibility that the emergency call will be redirected to a different AN, thereby reducing the delay required to successfully place the emergency call.