IP Multimedia Subsystem

About: IP Multimedia Subsystem is a research topic. Over the lifetime, 4398 publications have been published within this topic receiving 43698 citations.

Method, Apparatus, and System for Disaster Recovery of IMS

Abstract: A method, apparatus, and system for disaster recovery of an IP Multimedia Subsystem (IMS) are provided. The method includes: triggering a redundant Call Session Control Function (CSCF); obtaining, by the redundant CSCF, user backup data of registered IMS Private User Identities (IMPIs) that are associated with IMPUs and user service configuration data of IMS Public User Identities (IMPUs) in an IMS subscription from a network storage entity of a user; and recovering, by the redundant CSCF, a corresponding service according to the obtained user backup data of the registered IMPIs and user service configuration data of the IMPUs in the IMS subscription. With the present invention, the one-IMPU multi-IMPI, one-IMPI multi-IMPU, or multi-IMPI multi-IMPU service can be recovered, and this enables the user to have better service continuity experiences.

A framework to improve QoS and mobility management for multimedia applications in the IMS

Abstract: The new IP multimedia subsystem (IMS) provides an overlay architecture for IP based core networks and enables the efficient provision of an open set of potentially highly integrated multimedia services (i.e. instant messaging, video conferencing, VoIP, application sharing, etc) on top of possibly different access technologies. However, there will be different domains and IMSs managed by different ISPs (Internet service providers) in the Internet. Each ISP has an SLA (service level agreement) established between its users, which defines what kind of resources and prices was agreed to be offered to each user. However there is no SLA between a visited domain and a mobile user. This paper analyses how to extend the QoS capabilities of the IMS offered to a mobile terminal when it roams among different domains. We propose a framework that integrates QoS and mobility management. This integration envisages the improvement of the overall end-to-end performance and the reduction of management entities in the network. The architecture presents the domain policy manager (DPM) as the decision-making and controller of a domain. The proposed architecture uses policies with inter-domain negotiation. An application scenario to show the framework functionality is described as well as the current status of the implementation.

Call control scenarios in the "all-IP" UMTS core network

Abstract: This paper gives an overview of the 3GPP "all IP" architecture for the core network of UMTS. It presents some call control and network resource allocation scenarios using SIP for multimedia call management in a packet-switched network, UMTS/GPRS network and multimedia IP-based networks.

Active Location Reporting for Emergency Call in UMTS IP Multimedia Subsystem

Abstract: The IP Multimedia Core Network Subsystem (IMS) provides multimedia services for Universal Mobile Telecommunications System (UMTS). In IMS, an emergency call is established by an Emergency Call Session Control Function (ECSCF). The E-CSCF dispatches the call to the nearest Public Safety Answering Point (PSAP) according to the location of the caller. After emergency call setup, the caller's location is tracked by the PSAP through Location Polling. This paper investigates the performance of location tracking. Then we propose the Active Location Reporting scheme to improve the performance of location tracking. Our study indicates that the Active Location Reporting scheme may significantly outperform the Location Polling scheme.

Handover Delay Estimation Method for IMS-Based Systems with Heterogeneous Access Networks

Abstract: IP multimedia subsystem (IMS) is an architectural framework designed to merge the Internet and cellular networks, as such users can have access to the current and future services available over the Internet with their mobile devices anytime and virtually everywhere at affordable charges and faster rates, but heterogeneity of access networks in IMS-based systems makes handover process to be a critical issue, especially when moving from one access network to another access network with different technology, hence there is a need to devise a simple approach to estimate handover delay when moving to any access network. This paper proposes a simple method to estimate handover delay for IMS-based systems with heterogeneous access networks. The proposed method can be used to estimate handover delay for current and future access networks, but for illustration purpose, in the paper two access networks were considered, i.e. UMTS and WLAN. Numerical analysis conducted in the paper has shown that handover process to UMTS access network tends to be much longer than that of WLAN access network.