VoIP to Cellular Handover via Remote Call Initiation

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Solution Overview

Problem

Dual-mode devices face challenges in seamlessly switching active VoIP calls to cellular networks, especially when moving out of IP network coverage, as existing methods require establishing a new call from the VoIP interface to the cellular interface through a communication server, which can be complex and prone to errors.

Innovation Solution

A method that involves placing the active VoIP call on hold, establishing a second call from the VoIP interface to the cellular interface via a communications server, instructing the remote device to initiate a new call to the server, and replacing the VoIP leg with the cellular leg, thereby joining the remote party to the cellular interface, and terminating the original call.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a second call is established from the VoIP interface to the cellular interface through a communication server, then the handover process can be implemented, but the system complexity and error susceptibility increase

Engineering Contradiction:
Improvehandover capabilityVSAvoidcall establishment complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts the second call establishment step from the handover process by having the remote device initiate the call directly to the cellular interface without requiring a intermediate call through the communication server. This eliminates the complex intermediary call while maintaining the handover functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of establishing a second call from the VoIP interface to the cellular interface (conventional approach), the patent inverts the approach by having the remote device initiate the second call directly to the cellular interface. This reversal simplifies the call establishment process and reduces system complexity.

Inventive Principle:
Principle #13The other way round (Inversion)

2Area of stationary object

If the active VoIP call is switched to cellular network, then coverage beyond WLAN range is achieved, but call quality and user experience may be affected

Engineering Contradiction:
Improvecoverage areaVSAvoidcall quality
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The patent applies preliminary action by establishing the second call to the cellular interface before terminating the original VoIP call. This ensures that the cellular connection is ready and stable before switching, maintaining call quality during the transition and preventing interruptions that would degrade user experience.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If a second call is established through communication server, then handover can be achieved, but the process becomes prone to errors

Engineering Contradiction:
Improveinterface switching capabilityVSAvoidhandover reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent removes the problematic intermediary step by extracting the second call establishment from the VoIP interface through the communication server. The remote device directly initiates the second call to the cellular interface, eliminating the error-prone intermediary routing while maintaining the same handover adaptability.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP2018014B1Method for handover of session from VOIP interface to cellular interface in a dual-mode device
Publication Date: 2009.12.30 BLACKBERRY LTD
  • EP2018014B1 patent drawingFigure 1
  • EP2018014B1 patent drawingFigure 2
  • EP2018014B1 patent drawingFigure 3

AI summary

A dual-mode device (100) for handing over an active call from the device's VoIP interface to its cellular interface. The active call is placed on hold and a second call is established from the VoIP interface to the cellular interface of the dual-mode device, wherein the second call includes a VoIP leg from the VoIP interface of the dual-mode device to a communications server. The remote device (120) involved in the VoIP call is then instructed to initiate a new call to the communications server (60) referencing the second call and causing the communications server (60) to replace the VoIP leg of the second call with the new call, thereby joining the remote party (120) to the second call connected to the cellular interface of the dual-mode device (100). The active call is then terminated.