3G UMTS中的IP多媒体子系统探析

下一代的移动通信系统将基于全IP的网络构架,提供开放的业务生成环境。3GPP在其UMTSR5版本中首次引入了IP多媒体子系统(IMS)的概念,作为下一代网络的重要平台,IMS不仅实现了固网与移动网业务的无缝融合,还有利于运营商快速、灵活地开发更加丰富多彩的移动多媒体业务,从而吸引大量的终端用户。文章在描述IMS体系结构的基础上,特别针对IMS中几个关键要素点进行了重点分析。     

浅谈IP多媒体子系统业务平台

文章研究了3GPP在UMTSRel5、Rel6演进版本中提出的IP多媒体子系统(IMS),描述了IMS在基于分组域上提供电话和非电话业务的系统架构。IMS的提出对固网和移动网络的融合起到了很大的推动作用,研究基于IMS的统一业务平台对下一代业务平台体系架构具有一定参考意义。     

IMS关键技术及业务应用研究

3GPP UMTS体系标准的R5版本中引入的IMS是为支持移动多媒体业务而设计,是第三代移动通信核心网络的重要组成部分。论文首先对IMS的关键技术做了归纳总结,然后重点介绍了IMS的安全功能。在此基础上讨论了IMS中的业务架构和基本业务。     

VoIP Performance over HSPA with Different VoIP Clients

High Speed Packet Access (HSPA) Holma H, Toskala A (in HSDPA/HSUPA for UMTS, 2006) is expected to provide enough bandwidth for voice over IP (VoIP) service. In this article we assess the performance of VoIP over HSPA with different VoIP clients and voice codecs. The simulations results show that VoIP can have a good voice quality over HSPA if a proper VoIP client and codec is used. However it is possible that the delay can increase with early HSPA implementations (mobile, network).     

Multicast Broadcast Services Support in OFDMA-Based WiMAX Systems [Advances in Mobile Multimedia]

Multimedia stream service provided by broadband wireless networks has emerged as an important technology and has attracted much attention. An all-IP network architecture with reliable high-throughput air interface makes orthogonal frequency division multiplexing access (OFDMA)-based mobile worldwide interoperability for microwave access (mobile WiMAX) a viable technology for wireless multimedia services, such as voice over IP (VoIP), mobile TV, and so on. One of the main features in a WiMAX MAC layer is that it can provide'differentiated services among different traffic categories with individual QoS requirements. In this article, we first give an overview of the key aspects of WiMAX and describe multimedia broadcast multicast service (MBMS) architecture of the 3GPP. Then, we propose a multicast and broadcast service (MBS) architecture for WiMAX that is based on MBMS. Moreover, we enhance the MBS architecture for mobile WiMAX to overcome the shortcoming of limited video broadcast performance over the baseline MBS model. We also give examples to demonstrate that the proposed architecture can support better mobility and offer higher power efficiency.     

Policy-based QoS architecture in the IP multimedia subsystem of UMTS

The third-generation mobile system, or Universal Mobile Telecommunication System, will offer IP-based multimedia applications and services with end-to-end QoS guarantee. The key part providing these services is the policy-based QoS control architecture in the IP multimedia subsystem (IMS). In this tutorial we describe the network entities involved in the policy-based QoS architecture, their interactions to realize guaranteed QoS in the UMTS network, and the communication interfaces employed in the interactions.     

Hot topics for mobile services

Upcoming mobile technologies like the Universal Mobile Telecommunications System (UMTS) or Voice-Over-IP/IP Multimedia Subsystem (VoIP/IMS) offer new possibilities but also threats. Consequently, operators and vendors need to adopt appropriate technology and business principles. This article focuses on the concept of Service Platforms to allow flexible and fast service development, and enablers for Location Based Services.     

面向固定移动融合环境的P2PSIP系统设计

全业务运营是电信市场继语音和宽带接入服务之后的下一个增长点,而基于IP的融合有线网络和无线网络的语音服务则是全业务的重点之一。本文通过分析现有VoIP网络存在的问题以及固定移动融合网络环境下VoIP的特点,提出一种新型双层重叠网架构的P2PSIP架构,并阐述了新型架构的优点及双层重叠网之间的通信机制。新型架构能有效提高系统的安全性、健壮性和用户节点资源利用效率,更好的满足固定移动融合网络环境下VoIP对带宽、网络质量和安全性的要求。     

移动通信网中VHE的实现

首先介绍了UMTS中VHE的基本概念及其结构模型;之后介绍了UMTS中实现开放式业务体系的API技术;最后探讨了在第二代移动通信网利用API技术实现第三代移动通信网中VHE业务的方案。     

Mobile next-generation networks

Mobile next-generation networks (NGNs) are a necessary element in reaching the goal of truly ubiquitous computing. The Universal Mobile Telecommunication System, the third-generation mobile service concept, is a technology step to mobile NGNs. We can view NGNs as a merger of the Internet and intranets with mobile networks and with media and broadcast technologies. The Universal Mobile Telecommunication System (UMTS) is-from a radio perspective-a third-generation cellular technology, which is defined by the International Telecommunication Union (ITU) in its IMT-2000 framework (2001). From a conceptual point of view, it represents a technology step to mobile NGNs' facilitating ubiquitous computing. Researchers conceived UMTS to combine Internet protocol (IP) and mobile technologies to offer personal communication and personalized content everywhere. Its goal is to apply Internet protocols for mobile services control and end-to-end applications. By analyzing the trends of key technologies, we can see how they drive the evolution of the Internet and mobile communications toward mobile NGNs. In this article, I describe the IP-based approach of UMTS for the provision of mobile multimedia services. The integration of WLAN into the UMTS architecture could indicate that the field is moving toward separating mobile and fixed Internet.     

An Approach to Integrating SIP in Converged Multimodal/Multimedia Communication Services

In this paper, we present an approach of integrating SIP (Session Initiation Protocol) in converged multimodal/multimedia communication services. An extensible VoIPTeleserver for VoIP in SIP environment is described. It is based on the concept of dialogue system and Web convergence that separates the channel dependent media resources from the application dependent service creation and hosting environment. It supports XML based service applications for multiple channels including voice, DTMF, IM and chat over IP. The loosely coupled open architecture in our approach is highly extensible. We describe the concept and structure of VoIPTeleServer used in our approach in detail, which interfaces to the VoIP world through SIP signaling and works as a broker between the VoIP SIP environment and MTIP to deliver converged communication services. A prototype of VoIPTeleServer was implemented, and services and applications based on SIP and MTIP convergence are constructed. Special attention is given to the adverse effect of delay, jitter and packet loss for voice portal services over IP. In particular, case studies of DTMF service in voice portal under adverse channel conditions are performed. The compounding effects of multiple channel impairments to DTMF in voice portal services over IP are characterized. The potential high error rate of the DTMF service indicates that the data redundancy method as proposed in RFC 2198 is needed for DTMF in order to achieve reliable voice portal services over IP.     

基于MBMS的手机电视技术

多媒体广播组播业务(MBMS)是3GPP Release 6版本中引入的一项重大功能,目的在于节省系统资源,为用户提供广播或者组播的分组数据业务.作为一种具体的MBMS应用,手机电视技术在3G业务中占有重要的地位.文中介绍了多媒体广播和组播技术(MBMS),包括MBMS的网络结构、业务流程以及基于TD-SCDMA的MBMS系统架构,对LTE中的E-MBMS技术进行了初步研究,并从逻辑结构、业务模式和信道结构等方面简单分析了从MBMS到E-MBMS的演进.     

移动代理技术在UMTS系统中的应用

移动代理技术在移动智能网中的应用，是目前移动通信领域研究的热点之一。虚拟归属环境概念的提出为在第三代移动通信系统中应用移动代理技术提供了可能。本在重点介绍移动代理技术的基础上，阐述了移动代理技术在第三代移动通信系统UMTS中的应用：首先必须构造一个分布式的移动代理环境(DAE)，再实现基于移动代理技术的虚拟归属环境，从而完成出入呼叫处理。     

Managing IP traffic in radio access networks of next-generation mobile systems

The strong research, standardization, and development activity currently focusing on the enabling technologies for the transition to a new generation of mobile networks represent a great opportunity to accomplish the goal of IP multimedia service provisioning to mobile users. This will contribute to the migration toward an all-IP platform with guaranteed end-to-end QoS provisioning, and will definitively fuel the deployment of new multimedia mobile applications and the further development of multimedia ubiquitous communications. This objective is not easily achievable, mainly due to the difficulties in handling IP multimedia applications in a mobile environment with a guaranteed QoS level. To contribute to this issue, in this article we discuss an evolutionary scenario from the current UMTS system to a next-generation QoS-aware mobile platform based on IP as the transport solution in the radio access network, UTRAN. Furthermore, we propose to fit the IntServ-over-DiffServ approach, in order to best manage the QoS level inside the UTRAN.     

Evolutionary mobility and service support in DECT access networks

This paper presents an access-independent network architecture for supporting UMTS service capabilities. The approach is based on an enhanced B-ISDN core network with personal and terminal mobility provided by intelligent network techniques. A physical realization is presented, and the protocols corresponding to the physical interfaces are identified. Protocols are proposed for UMTS mobility and service support, and the impact on the B-UNI and IN interfaces is considered. Reflecting the vision of the ETSI global multimedia mobility (GMM) standardization framework, UMTS service support through non-UMTS access is considered. Consideration of DECT as a UMTS access technology leads to an interworking proposal that presents each DECT terminal to the core network in terms of UMTS functional entities. Access-independent usage of UMTS terminal applications motivates additional interworking in the terminal to encapsulate the access network. The desirability of an access-independent UMTS application programming interface in the terminal is indicated     

iPTT: peer‐to‐peer push‐to‐talk for VoIP

This paper proposes iPTT, a peer‐to‐peer (P2P) Push‐to‐Talk (PTT) service for Voice over IP (VoIP). In iPTT, a distributed and mobile‐operator independent network architecture is presented to accelerate the deployment of the PTT service. Based on the serverless architecture, we develop two mechanisms, that is, flooding‐based floor control mechanism (FFC) and tree‐based floor control mechanism (TFC), for real‐time talk‐burst determination. The determination algorithms and the corresponding message flows for these two mechanisms are designed to show the feasibility of FFC and TFC. The performance of FFC and TFC is investigated through our analytical and simulation models in terms of the determination latency and the number of floor‐control message exchanges. Copyright © 2008 John Wiley & Sons, Ltd.     

vGPRS: A Mechanism for Voice over GPRS

This paper proposes vGPRS, a voice over IP (VoIP) mechanism for general packet radio service (GPRS) network. In this approach, a new network element called VoIP mobile switching center (VMSC) is introduced to replace standard GSM MSC. Both standard GSM and GPRS mobile stations can be used to receive real-time VoIP service, which need not be equipped with the VoIP (i.e., H.323) terminal capabilities. The vGPRS approach is implemented using standard H.323, GPRS, and GSM protocols. Thus, existing GPRS and H.323 network elements are not modified. Furthermore, the message flows for vGPRS registration, call origination, call release and call termination procedures are described to show the feasibility of our vGPRS system.     

Multi-domain architecture for policy management inumts ip multimedia subsystem

The Universal Mobile Telecommunications System (UMTS) offers IP-based multimedia applications and services with end-to-end Quality of Service (QoS) guarantee. The key component providing these services is the IP Multimedia Subsystem (IMS) that uses Service-Based Local Policy (SBLP) management for QoS control. To support end-to-end QoS, the UMTS IMS network should be scalable, reliable and flexible in policy deployment and enforcement, characteristics that are not found in single-domain policy architecture. A hybrid policy architecture is proposed, in which a hierarchical architecture is applied to the multi-domain environment in a single operator UMTS IMS network, while a peering architecture is employed in a multi-operator UMTS IMS network. The proposed multi-domain policy architecture potentially minimizes the session setup delay and policy exchange traffic while maximizing network scalability.     

The multimedia broadcast/multicast service

This article provides an overview of the multimedia broadcast/multicast service (MBMS) for universal mobile telecommunications system (UMTS) networks. We first outline the features of UMTS networks as defined by the 3rd generation partnership project (3GPP) in order to provide a background for the discussion to follow. We then present the overall MBMS architecture, the services that it provides to the users and the differences between the broadcast and multicast options. The implementation details of MBMS are explained in terms of the modifications needed to the network, the new signaling procedures required and the impact of MBMS on the radio part of the network. We then describe how the security architecture of UMTS is used to support content protection and key distribution for MBMS groups. We evaluate the prospects of MBMS by comparing it first with IP multicast and then with DVB‐H, considered by many to be the closest competitor of MBMS. Finally, we conclude with a discussion of the technical and business challenges still faced by MBMS. Copyright © 2006 John Wiley & Sons, Ltd.     

UMTS-mobile communications beyond the year 2000: requirements,architecture and system options

To support the massive demand for mobile services third generation land mobile systems will be based on a new architecture concept and adaptive techniques. Moreover, these systems are expected to offer service quality comparable to that of fixed networks contemporary to their deployment. UMTS (universal mobile telecommunication system) is the developing pan-European concept for third generation mobile systems. The paper briefly overviews the requirements for and the emerging architecture of the UMTS as they appear at the transition between two RACE research phases and the beginning of dedicated standardisation activity in ETSI