Bringing Location Based Services to IP Multimedia Subsystem

Abstract

As a result of the evolution of computer and networking technologies, the Third Generation Partnership Project (3GPP) has proposed the IP Multimedia Subsystem (IMS) as a key element in the UMTS architecture supporting multimedia services in the packet switched domain. Extending the IMS with support for location based services (LBS) will enable enhanced services and offer new revenues to the system. Connecting the IMS core network with a real positioning system providing support for LBS is an open issue. This paper addresses this issue and presents the design and implementation of an IMS Location Server (ILS) connecting the IMS with a positioning system. From the IMS perspective, ILS serves as a service enabler for LBS in the mentioned subsystem. In order to demonstrate proof-of-concept in enhancing IMS-based services, a Location-aware Push-to-Talk (LaPoC) prototype service has been developed. The service has been integrated with the Ericsson Mobile Positioning System (MPS). This paper also gives the results of performance measurements including traffic load analysis and session establishment time.

Combination of LTE and IMS to deliver location based services

“…Paper [3] extends the IMS with support for LBS that enables enhanced services and offers new revenues to the system. It also addresses the issue of connecting the IMS core network to the location server located in the service layer of IMS networks.…”

The Position Location Problem

“…This is the case with cellular systems that base mobile position-estimation on received field strength, propagation delay, and observed angles of arrival, using only the cellular system's infrastructure and the system's networking facilities, which obviously have not been designed specifically for localization purposes. Another example is Internet protocol (IP)-based localization, where a user may be identified through the declared IP address of the nearest server [6,7].…”

An Evaluation of Context-Aware Infomobility Systems

“…The advantage of such an approach is to enhance locationbased services with value-added features provided by the IMS architecture, such as Quality of Service support, standard-based service integration over an IP-based infrastructure and charging facilities. Mosmondor et al (2006) propose an extension of the IMS architecture by designing and implementing an IMS Location Server that provides IMS and IMS application servers with location information obtained from different positioning systems. The IMS Location Server is a generic SIP Application Server that can obtain location information from network-based positioning systems via Mobile Location Protocol (MLP) (Open Mobile Alliance, 2007).…”