’Reachability’ in converged IMS services — a BT Alcatel-Lucent collaboration

Cellular mobile is at an important crossroads -with the industry still in the process of attempting a transition from the dominant second generation services of voice and messaging, to data-based services such as music download and gaming. Third generation technology has rolled out slowly in Europe and has yet to make much of an impact on the market. Against this backdrop, the cellular industry is now moving towards defining fourth generation mobile for introduction in 2012-2015. The emergence of new, non-cellular systems, such as WiMAX and WLAN are confusing the timeline and evolution of cellular systems with a heated debate about what constitutes a '4G system'. In addition, some people view convergence as the next generation of mobile with less emphasis on raw connection speed and more on access to the same services over a range of access technologies and devices. In this paper we critically examine these and other views of fourth generation mobile (4G) and identify the key technological, standards-related and commercial issues that will drive the evolution of 4G over the next few years.

Section: Convergence As a Candidate For 4gmentioning

confidence: 98%

Cellular mobile — the generation game

Wisely¹

2007

“…Its relevance to the work requirements described in section 2.1 consists of the ability to address reusability of component and speed to market for new services [9].…”

Section: • Imsmentioning

confidence: 99%

“…The application requirements are conveyed through the control block's call session control functions (x-CSCFs) or more generic SIP proxies to the policy decision function (PDF) or their equivalents -policy decision points (PDPs) in IETF and resource allocation control sub-system (RACS) in TISPAN -which then mediate the reservation of physical resources on the access networks through the allocation of appropriate bearers (PDP-contexts [9], WLAN and WiMAX bearers, etc). These bearers are then physically enforced Some level of reconfiguration of allocated resources can be achieved through the IMS control blocks (x-CSCFs), which allow the renegotiation of the bearer's (i.e.…”

Section: A Simplified Next Generation Network (Ngn) Architecturementioning

confidence: 99%

“…The network is therefore able to build a dynamic information system (stored at the PDP) providing timely information to the handover decision engine (HDE) implemented in the network. The HDE may initiate a handover procedure [9] for a specific terminal taking into account user profiles (stored in the PDF) and application requirements. It should be noted that even though PDP and HDE are two different logical components it is most likely that they will be physically collocated.…”

Section: 2mentioning

confidence: 99%

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Network enablers for enhanced mobility management

Giaffreda¹,

Carvalho²,

Melia³

2007

The proliferation of network access technologies and the increased mobility of end users bring new challenges to operators who are willing to support their subscribers with seamless and context-aware services. This paper reviews the requirements that these challenges generate, focusing on the issues that are not entirely addressed by existing mobility protocols, the IMS set of specifications or by the IEEE802.21 standardisation efforts. A set of network enablers for enhanced mobility management addressing these issues is then proposed with an explanation of their positioning within future IMS-based mobility architectures. IntroductionIn recent years, faced with declining revenues in the traditional voice calls market, telecommunications operators have sought to find new business opportunities to grow revenues and counter the threat of commoditisation of network traffic.One such new opportunity that has emerged is that of converged services. These are services which need to reach the users regardless of whether they are at a fixed location or accessing the network through various access technologies while on the move.The current industry de facto mobility architecture poised to enable new revenues is the IP multimedia subsystem (IMS). Created by the 3GPP to evolve circuitswitched networks to support packet-switched applications, the IMS allows separation of session control from data transport. Its operations are complemented by a number of protocols from the Internet community (e.g. Mobile-IP, SIP) which support terminal/session mobility. These protocols, designed as a patch to enhance fixed IP networks, while supporting some mobile users' requirements, also impose limitations that can often prevent service continuity.As a result, existing converged service solutions fall short of providing a guaranteed seamless handover experience as the comprehensive information required to support the handover decisions is not available to the service. The IEEE802.21 standard aims to improve the support by enlarging the information space considered during handover, limiting the more dynamic information to radio signal level triggers. These triggers are increasingly inadequate, especially when considering ubiquitous networking scenarios which, coupled with increased availability of devices, offer a number of alternatives for the best delivery of individual services given the current user/ device/network context.It is argued in this paper therefore, that further enhancements, namely the use of information elements which are more dynamic and originate in different layers and which represent user, service and network context, can greatly benefit the operations of a network-based mobility management capability. This paper is divided into a number of sections. Section 2 illustrates the main requirements that future mobility architectures need to support; it then shows how current standards-based specifications address some aspects of those requirements and highlights a number of unresolved issues. Section 3 proposes selected solution...

“…BT's 21CN is based on the IP multimedia sub-system (IMS) standard architecture, which in turn is based on SIP [1,2]. Since the goal of the IMS is to provide ubiquitous access to all existing and future Internet services, adopting SIP as the control protocol for IMS brings immediate access to some of today's most popular and fastest growing Internet services.…”

Section: Introductionmentioning

confidence: 99%

SIP mediated services

Reid¹,

Aparicio²,

Low³

2007

In this paper we discuss how we can use the session initiation protocol (SIP) to offer advanced services for mobile users over BT's 21st Century Network (21CN). We provide a brief overview of the advantages of using SIP and describe how SIP can play a vital role in today's and future heterogeneous networks, such as BT's 21CN. We demonstrate some advantages of using SIP for handover in these varied networks and we compare it against using other methods for handover, e.g. mobile IP.With the current and anticipated demand for users with multiple devices, we introduce the benefits of using SIP for personal mobility, including the concept of transferring sessions between a user's many and varied devices.We then consider quality of service issues that present themselves when moving frequently between varied, particularly wireless, networks with varying capabilities and congestion. We describe how we have used codec switching to cope with these adverse conditions, and consider the benefits of shifting the control of this adaptation to the network.This work centres on a custom-built test-bed together with our own real-time SIP-based videoconferencing application with codec switching capability. We present this test-bed, and results based on its use.