VoIP Call Transfer via IM in IMS

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Solution Overview

Problem

Current IP multimedia subsystems do not support call transfer functionality for Voice over IP (VoIP) users, lacking the necessary provisions for seamless call transfer among VoIP users.

Innovation Solution

The IP multimedia subsystem is enhanced by utilizing the Instant Messaging capability within the system to facilitate call transfer, where the Serving Call Session Control Function (S-CSCF) application modifies SIP communications to include an Instant Messaging identifier, allowing the Application Server to process the request as an Instant Message and manage the call transfer process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the IP multimedia subsystem uses standard SIP communications for call control, then the system maintains protocol compliance and simplicity, but call transfer functionality cannot be supported among VoIP users

Engineering Contradiction:

Improvecall transfer functionalityVSAvoidcommunication processing complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies multi-functionality by enabling the Instant Messaging capability to serve dual purposes: traditional instant messaging between users and call transfer requests from VoIP users. The S-CSCF modifies SIP communications to include IM identifiers, allowing the same IM processing path to handle both messaging and call transfer functions, thereby adding call transfer capability without requiring a separate dedicated call transfer processing path.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent introduces an intermediary mechanism where the S-CSCF acts as a mediator between the incoming SIP communication and the AS application. By modifying the SIP message to include an IM identifier and routing it through the IM capability, the system creates an intermediate processing layer that translates call transfer requests into IM-style communications that the AS can process using existing IM logic.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the system processes call transfer requests as standard SIP communications, then VoIP call control remains straightforward, but the Instant Messaging capability cannot be utilized

Engineering Contradiction:

ImproveInstant Messaging capability utilizationVSAvoidcall transfer operation simplicity

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent makes the Instant Messaging capability universal by enabling it to handle both traditional IM messages and call transfer requests. The S-CSCF identifies call transfer requests by their SIP communication structure and modifies them to include IM identifiers, allowing the AS to process both IM and call transfer functions through the same IM processing path.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent changes the parameter structure of SIP communications by adding an IM identifier field to messages that are to be processed as call transfer requests. This parameter modification allows the system to distinguish call transfer requests from regular IM messages while maintaining compatibility with the existing IM processing infrastructure.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If the IP multimedia subsystem adds dedicated call transfer processing mechanisms, then call transfer functionality is achieved, but the system structure becomes more complex

Engineering Contradiction:

Improvecall transfer service capabilityVSAvoidsystem structure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent avoids adding dedicated call transfer processing mechanisms by making the existing Instant Messaging capability universal. The S-CSCF modifies SIP communications to include IM identifiers, allowing the AS to process call transfer requests through the existing IM processing path, thereby achieving call transfer functionality without duplicating or adding separate processing infrastructure.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent applies self-service by enabling the Instant Messaging capability to serve itself by handling both traditional IM messages and call transfer requests through the same processing path. The S-CSCF's modification of SIP messages to include IM identifiers allows the system to route call transfer requests through the existing IM handling logic, eliminating the need for separate dedicated call transfer processing mechanisms.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS7586903B2System and method for VoIP call transfer using instant message service in an IP multimedia subsystem

Publication Date: 2009.09.08 SAMSUNG ELECTRONICS CO LTD

AI summary

The Instant Messaging capability of an IP multimedia subsystem is utilized to support call transfer service for VoIP users. A call transfer request from a first VoIP user to a second VoIP user is sent to the IP multimedia subsystem in a predetermined non-standard SIP communication. The IP multimedia subsystem invokes Instant Messaging service in response to the predetermined non-standard SIP communication, and Instant Messaging service is then utilized to support the call transfer dialogue.