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Salkintzis and Nikos Passas 1.1 Evolving Towards Wireless Multimedia Networks 1 1.7 Hybrid Multimedia Networks and Seamless Mobility 10 Part One Multimedia Enabling Technologies 2 Multim

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Library of Congress Cataloging-in-Publication Data

Emerging wireless multimedia services and technologies/edited by A Salkintzis, N Passas.

British Library Cataloguing in Publication Data

A catalogue record for this book is available from the British Library

ISBN-13 978-0-470-02149-1 (HB)

ISBN-10 0-470-02149-7 (HB)

Typeset in 9/11pt Times by Thomson Press (India) Limited, New Delhi.

Printed and bound in Great Britain by Antony Rowe Ltd, Chippenham, Wiltshire.

This book is printed on acid-free paper responsibly manufactured from sustainable forestry

in which at least two trees are planted for each one used for paper production.

with endless understanding, love and patience.

Apostolis K Salkintzis

To my wife Kitty, for her unconditional love, and to my daughter Dimitra,

for coming into my life.

Nikos Passas

List of Contributors xvii

Apostolis K Salkintzis and Nikos Passas

1.1 Evolving Towards Wireless Multimedia Networks 1

1.7 Hybrid Multimedia Networks and Seamless Mobility 10

Part One Multimedia Enabling Technologies

2 Multimedia Coding Techniques for Wireless Networks 17Anastasios Delopoulos

2.2.1 Entropy, Entropy Reduction and Entropy Coding 19

2.6.2 Discrete Representation of Video – Digital Video 37

3.2.2 Non-Real-time and Real-time Multimedia Services 50

3.2.4 Transmission of VBR Content Over Constant

3.6 Protocols for Multimedia-based Communication Over

3.6.1 Why TCP is not Suitable for Real-time Services 61

3.7.1 Multimedia Session with RTP or how RTP is Used 63

3.7.4 How Intra-media and Inter-media Synchronization

3.7.5 Monitoring RTT, Jitter and Packet Loss Rate 70

3.8.1 RTP Profiles for Audio and Video Conferences (RFC3551) 72

4 Multimedia Control Protocols for Wireless Networks 83Pedro M Ruiz, Eduardo Martı´nez, Juan A Sa´nchez and Antonio

F Go´mez-Skarmeta

4.2 A Premier on the Control Plane of Existing Multimedia Standards 844.2.1 ITU Protocols for Videoconferencing on Packet-switched Networks 844.2.2 IETF Multimedia Internetworking Protocols 874.2.3 Control Protocols for Wireless Networks 894.3 Protocol for Describing Multimedia Sessions: SDP 90

4.8 Research Challenges and Opportunities 118

5.4.4 Association Control Function (ACF) 1305.4.5 Signaling and Radio Resource Management 131

5.4.6 Convergence Layer 1325.4.7 Throughput Performance of HiperLAN/2 132

5.5.1 Distributed Coordination Function 133

5.6 Overview of IEEE 802.11 Standardization 136

5.8 Simulation Performance of IEEE 802.11 146

5.8.2 Throughput vs Number of Stations 148

5.9.1 Comparison of Simulation and Analysis for VoIP Traffic 1515.10 Video Transmission Over IEEE 802.11E 152

5.A Appendix: Analysis of the Frame Error Rate and Backoff Process of EDCA Using

5.A.4 Throughput Analysis for EDCA Bursting 165

6.3.3 Description of Bluetooth1Links and Packets 174

6.3.5 Secret Discovery and Connection Establishment 1775.10.2 Scenario 2: TXOP Limit vs Medium Accessing

6.5.3 Piconet Formation and Maintenance 186

7.5.2 Signaling During UMTS-to-WLAN Handover 221

George Xylomenos and Vasilis Vogkas

8.3.1 Services and Service Capabilities 239

8.4.2 Multimedia Broadcast/Multicast Service 244

Part Two Wireless Multimedia Applications and Services

Alessandro Andreadis and Giovanni Giambene

9.1 Introduction to WAP Protocol and Architecture 2639.1.1 WAP-based Multimedia Services: Potentials and Limitations 266

9.2.4 Wireless Transport Layer Security 273

9.3.3 Conversion of Existing Wepages to WAP 2789.3.4 Dynamic Content Adaptation for WAP Pages Delivery 279

9.5 Performance of WAP over 2G and 2.5G Technologies 2829.5.1 WAP Traffic Modeling Issues and Performance Evaluation 2829.6 Examples of Experimented and Implemented WAP Services 286

Alessandro Andreadis and Giovanni Giambene

10.1 Evolution From Short to Multimedia Message Services 293

10.2.1 Detailed Description of MMS Architecture Elements 295

11.5.1 Authentication, Confidentiality/Privacy and Integrity 339

11.5.3 Gateways and End-to-End Services 340

11.5.5 Security Features of Specific Standards 342

11.6.3 Context-Aware Instant Messaging 345

12 Instant Messaging Enabled Mobile Payments 349Stamatis Karnouskos, Tadaaki Arimura, Shigetoshi

Yokoyama and Bala´zs Csik

13.6.5 Talker Arbitration Delay on GPRS 39013.6.6 Capacity Impacts on GPRS Networks 39013.6.7 PTT Capacity Relative to Cellular Voice Calls 391

13.8 Possible Future, or PTT Evolving to PTX 393

14 Location Based Services 395Ioannis Priggouris, Stathes Hadjiefthymiades and Giannis Marias

Communication Networks Laboratory, Department of Informatics and

Telecommunications, University of Athens, Greece

Introduction

Apostolis K Salkintzis and Nikos Passas

1.1 Evolving Wireless Multimedia Networks

The objective of this chapter is to provide a brief and yet comprehensive introduction to the evolving ofwireless multimedia networks and the key technological aspects and challenges associated with thisevolution In this context, we aim at defining the appropriate framework for the emerging wirelessmultimedia technologies and the applications that are described in subsequent chapters of this book.Undoubtedly, the most widely supported evolving path of wireless networks today is the path towardsInternet Protocol-based (IP-based) networks, also known as all-IP networks The term ‘all-IP’emphasizes the fact that IP-based protocols are used for all purposes, including transport, mobility,security, QoS, application-level signaling, multimedia service provisioning, etc In a typical all-IPnetwork architecture, several wireless and fixed access networks are connected to a common coremultimedia network, as illustrated in Figure 1.1 Users are able to use multimedia applications overterminals with (ideally) software-configurable radios, capable of supporting a vast range of radio accesstechnologies, such as Wireless Local Area Networks (WLANs), Wireless Personal Area Networks(WPANs), 3G Cellular such as Universal Mobile Telecommunication System (UMTS), Code DivisionMultiple Access 2000 (cdma2000), etc In this environment, seamless mobility across the differentaccess networks is considered to be a key issue Also, native multimedia support by these networks isvery important For this reason, we devote some of the sections below to providing a brief introduction

to the features of these networks in relation to multimedia service provision

In the all-IP network architecture shown in Figure 1.1, the mobile terminals use the IP-basedprotocols defined by the Internet Engineering Task Force (IETF) to communicate with the multimedia IPnetwork and perform, for example, session/call control and traffic routing All services in thisarchitecture are provided on top of IP protocol As shown in the protocol architecture of Figure 1.2,the mobile networks, such as UMTS, cdma2000, etc., turn into access networks that provide only mobilebearer services The teleservices in these networks (e.g cellular voice) are used only to support thelegacy 2G and 3G terminals, which do not support IP-based applications (e.g IP telephony) On the userplane, protocols such as the Real Time Protocol (RTP) and the Real Time Streaming Protocol (RTSP)are employed These user-plane protocols are addressed extensively in Chapter 3 On the other hand, onthe control plane, protocols such as the Session Initiation Protocol (SIP) and Resource Reservation

Emerging Wireless Multimedia: Services and Technologies Edited by A Salkintzis and N Passas

# 2005 John Wiley & Sons, Ltd

Figure 1.1 Multimedia IP network architecture with various access technologies.

UTRAN User plane

Cdma2000 User plane

UTRAN Control plane

IP TCP/UDP

SIP

Cdma2000 Control plane

Access Network Signaling e.g 24.008, IS-136 Radio Access Signaling e.g RRC, RLC

GSM-MAP IS-41 UTRAN, GERAN, cdma2000

All-IP Core Network

Core Network Signaling e.g SIP

GPRS User plane

Protocol (RSVP) are employed Chapters 4 and 7 provide a deeper discussion on these control-planeprotocols.

For the provision of mobile bearer services, the access networks mainly implement micro-mobilitymanagement, radio resource management, and traffic management for provisioning of quality of service.Micro-mobility management in UMTS access networks is based on GPRS Tunneling Protocol (GTP) [1]and uses a hierarchical tunneling scheme for data forwarding On the other hand, micro-mobilitymanagement in cdma2000 access networks is based on IP micro-mobility protocols Macro-mobility,i.e mobility across different access networks, is typically based on Mobile-IP, as per RFC 3344 [2]

In the short term, the all-IP network architecture would provide a new communications paradigmbased on integrated voice, video and data You could, for instance, call a user’s IP MultimediaSubsystem (IMS) number and be redirected to his web page, where you could have several options, e.g.write an email to him, record a voice message, click on an alternative number to call if he is on vacation,etc You could also place a SIP call (as discussed in Chapter 4) to a server and update yourcommunication preferences, which could be in the form ‘only my manager can call me, all othersare redirected to my web page’ (or vice versa!) At the same time, you could be on a conference callbriefing your colleagues about the outcome of a meeting

1.1.1 Key Aspects of the Evolution

It is instructive at this point to record the key aspects of the evolution towards the wireless multimedianetwork architecture shown in Figure 1.1 This is because many of these aspects constitute the mainfocus of this book and are extensively discussed in the following chapters By briefly referring to theseaspects at this point we define an appropriate framework, which entails most of the topics discussed inthis book In short, the most important aspects relevant to the evolution toward the wireless multimedianetworks are as follows:

Wireless networks will evolve to an architecture encompassing an IP-based multimedia core networkand many wireless access networks (Figure 1.1) As discussed above, the key aspect in thisarchitecture is that signaling with the multimedia core network is based on IP protocols (morecorrectly, on protocols developed by IETF) and it is independent of the access network (be it UMTS,cdma2000, WLAN, etc.) Therefore, the same IP-based services could be accessed over any accessnetwork An IP-based core network uses IP-based protocols for all purposes, including data transport,networking, mobility, multimedia service provisioning, etc The first commercial approach towardsthis IP-based multimedia core network is the co-called IP Multimedia Core Network Subsystem(IMS) standardized by 3GPP and 3GPP2 We further discuss IMS in Chapter 8 along with the MobileBroadcast/Multicast Service (MBMS)

The long-term trend is towards all-IP mobile networks, where not only the core network but also theradio access network is based solely on IP technology In this approach, the base stations in a cellularsystem are IP access routers and mobility/session management is carried out with IP-based protocols(possibly substituting the cellular-specific mobility/session management protocols, such as GTP)

Enhanced IP multimedia applications will be enabled in wireless network by means of level signaling protocols standardized by IETF (e.g SIP, HTTP, etc.) Such protocols are discussedfurther in Chapters 3 and 4

application-
End-to-end QoS provisioning will be important for supporting the demanding multimedia tions In this context, extended interworking between, for example, UMTS QoS and IP QoS schemes

applica-is needed or, more generally, interworking between layer-2 QoS schemes and layer-3 QoS (i.e IPQoS) is required for end-to-end QoS provision The provision of QoS in multimedia networks is themain topic of Chapter 7

Voice over IP (VoIP) will be a key technology As discussed in Chapter 4, several standards tions are specifying the technology to enable VoIP, e.g ETSI BRAN TIPHON project, IETF SIP

organiza-WG, etc

The mobile terminals will be based on software-configurable radios with capabilities to supportmany radio access technologies across many frequency bands.

The ability to move across hybrid access technologies will be an important requirement, whichcalls for efficient and fast vertical handovers and seamless mobility The IETF working groupsSEAMOBY and MOBILE-IP are addressing some of the issues related to seamless mobility FastMobile IP and Micro-mobility schemes are key technologies in this area We provide moreinformation on seamless mobility in Chapter 7, where we study seamless video continuity acrossUMTS and WLAN

In a highly hybrid access environment, security will also play a key role IEEE 802.11 task group I(TGi) has standardizing new mechanisms for enhanced security in WLANs and also the IETFSEAMOBY group addresses the protocols that deal with (security) context transfer during handovers

For extended roaming between different administrative domains and/or different access technologies,advanced AAA protocols and AAA interworking mechanisms will be implemented

Wireless Personal Area Networks (WPANs) will play a significant role in the multimedia landscape.WPANs have already start spreading and they will get integrated with the hybrid multimedianetwork architecture, initially providing services based on the Bluetooth technology (see www.bluetooth.com) and later based on IEEE 802.15.3 high-speed wireless PAN technology, whichsatisfies the requirement of the digital consumer electronics market (e.g wireless video commu-nications between a PC and a video camera) WPANs are extensively discussed in Chapter 6

Wireless Local Area Networks (WLANs) will also contribute considerably to the wireless media provisioning WLAN technology will evolve further and will support much higher bit rates,

multi-in the order of hundreds of Mbps This is bemulti-ing addressed by the IEEE Wireless Next GenerationStanding Committee (see www.ieee802.org/11) WLANs for multimedia services are the main topic

of Chapter 5

As mentioned before, most of the above aspects of the evolution toward the wireless multimedianetworks are further discussed in subsequent chapters, mainly Chapters 3–8, which address theemerging multimedia technologies for wireless networks

1.2 Multimedia over Wireless

The evolutionary aspects summarized above call for several technological advances, which are coupledwith new technological challenges These challenges become even tougher when we consider thelimitations of wireless environments One of the most important challenges is the support of multimediaservices, such as video broadcasting, video conferencing, combined voice and video applications, etc.The demand for high bandwidth is definitely the key issue for these services, but it is not enough Othermajor requirements that should also be considered include seamless mobility, security, context-awareness, flexible charging and unified QoS support, to name but a few

1.2.1 IP over Wireless Networks

Owing to the widespread adoption of IP, most of multimedia services are IP-based The IP protocol, up

to version 4 (IPv4), was designed for fixed networks and ‘best effort’ applications with low networkrequirements, such as e-mail and file transfer and, accordingly, it offers an unreliable service that issubject to packet loss, reordering, packet duplication and unbounded delays This service is completelyinappropriate for real-time multimedia services such as video-conference and voice-over-IP, which callfor specific delay and loss figures Additionally, no mobility support is natively provided, making itdifficult for pure IP to be used for mobile communications One of the benefits of version 6 of IP (IPv6)

is that it inherently provides some means for QoS and mobility support, but it still needs supportingmechanisms to fulfil the demanding requirements that emerge in the hybrid architecture of Figure 1.1