IMS Location Service via SIP and XML-MLP

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Solution Overview

Problem

The implementation of Location Services (LCS) in IMS-based networks is inefficient, particularly due to the reliance on MAP interfaces for interworking with 3G networks, and involves cumbersome retransmission of location service requests when a user roams and changes network elements.

Innovation Solution

The method involves transmitting location service requests and responses using SIP messages, incorporating XML-based MLP messages within the Session Description Protocol (SDP) area, which eliminates the need for additional servers and simplifies communication through Proxy/Serving/Interrogating Call Session Control Functions, thereby bypassing the need for MAP interfaces and facilitating mobility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If MAP interfaces are used for interworking with 3G networks, then location service compatibility is achieved, but system complexity increases

Engineering Contradiction:

Improvelocation service compatibilityVSAvoidsystem complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts the location service request processing from the complex MAP interface pathway and implements it directly within the IMS network using SIP messages. The LIMS-IWF retrieves location information from the HSS/HLR through simplified SIP-based Sh and Dh interfaces, eliminating the need for MAP protocol translation and reducing system complexity while maintaining compatibility.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If traditional LCS request retransmission is performed during user roaming, then location service continuity is maintained, but signaling overhead increases

Engineering Contradiction:

Improvelocation service continuityVSAvoidsignaling overhead

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent implements preliminary action by having the LIMS-IWF proactively retrieve and cache location information from the HSS/HLR before it is needed for LCS service delivery. When a user roams to a new network element, the pre-retrieved location information is already available, eliminating the need for retransmission of LCS requests and reducing signaling overhead while maintaining service continuity.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If additional servers are deployed for LCS interworking, then location service functionality is enhanced, but network complexity increases

Engineering Contradiction:

Improvelocation service functionalityVSAvoidnetwork complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies universality by enabling the LIMS-IWF to perform multiple functions: it acts as both the LCS client interface and the location information retrieval point, while also functioning as the SIP message router within the IMS network. The HSS/HLR serves dual purposes as both subscriber database and location information repository. This multi-functionality eliminates the need for dedicated additional servers while enhancing location service functionality.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS7729705B2Method of providing location service over IMS network

Publication Date: 2010.06.01 SAMSUNG ELECTRONICS CO LTD

AI summary

A method of providing Location Services (LCS) over an Internet Protocol Multimedia Subsystem (IMS) network in a wireless communication system is provided. An LCS client transmits a service connection request message including a message requesting the location information of a User Equipment (UE). The UE transmits the location information to the LCS client.