emerging wireless multimedia services and technologies phần 7 doc

The next step is for both UEs to independently activate appropriate PDP contexts at their GGSNs, using the binding information returned by the PDFs. The included authorization tokens are passed by each PEF at the GGSN to its PDF to determine the amount of resources that have been authorized; if these equal or supersede those requested, each PEF installs the corresponding filters, reports it to the PDF and informs the UE that the PDP contexts have been activated. At this point the reservation of resources is complete but the gates are closed, since the session has not been established. Eventually the session is established, as indicated by a final SIP message sent by the called UE to the caller UE via the CSCFs. As this message passes through the PCF at each P-CSCF, the PCF instructs the PEF at the GGSN to open the gates, and the PEF confirms that the gates have indeed been opened. When the final SIP message reaches the caller UE, the gates are already open at both GGSNs, therefore session data may start flowing in both directions. 8.8 Summary This chapter provided an introduction to the support for IP based multimedia services on 3G wireless cellular networks, focusing on the IP Multimedia Subsystem (IMS) and the Multimedia Broadcast/ Multicast Service (MBMS). An overview of cellular networks in general and UMTS networks in particular was first presented to lay the groundwork for the following discussion. Then the features and services of the IMS and the MBMS were introduced, followed by detailed descriptions of both. Finally, the QoS issues for IP based multimedia services were discussed, emphasizing the policy based QoS control scheme of UMTS and its application to the IMS. 8.9 Glossary of Acronyms 1G/2G/3G First/Second/Third Generation 3GPP 3rd Generation Partnership Project 3GPP2 3rd Generation Partnership Project 2 AAL2/5 ATM Adaptation Layer 2/5 AMPS Advanced Mobile Phone Service AMR Adaptive Multi-Rate AS Application Server ATM Asynchronous Transfer Mode BGCF Breakout Gateway Control Function BM-SC Broadcast / Multicast Service Center BSC Base Station Controller P-CSCF S-CSCF UE PCF GGSN S-CSCF PCF GGSN P-CSCF UE COPS-PR SIP SIP SIPSIPSIP COPS-PR Data DataData Figure 8.16 QoS setup example. 256 Wireless Multimedia in 3G networks BSS Base Station Subsystem BTS Base Transceiver Station CBC Cell Broadcast Center CBS Cell Broadcast Service CDMA Code Division Multiple Access CN Core Network COPS Common Open Policy Service COPS-PR COPS for Policy Provisioning CS Circuit Switched D-AMPS Digital Advanced Mobile Phone Service DNS Domain Name System EDGE Enhanced Data Rates for GSM Evolution ETSI European Telecommunications Standards Institute FDD Frequency Division Duplexing FDMA Frequency Division Multiple Access GERAN GSM EDGE Radio Access Network GGSN Gateway GPRS Support Node GMSC Gateway Mobile services Switching Center GPRS General Packet Radio Service GSM Global System for Mobile Communications GSN GPRS Support Node HSCSD High Speed Circuit Switched Data HSS Home Subscriber Server I-CSCF Interrogating Call State Control Function IGMP Internet Group Management Protocol IMS IP Multimedia Subsystem IMT-2000 International Mobile Telecommunications 2000 IPv4/6 IP version 4/6 ISDN Integrated Services Digital Network ITU International Telecommunications Union IWF InterWorking Function MBMS Multimedia Broadcast/Multicast Service MGCF Media Gateway Control Function MGW Media GateWay MLD Multicast Listener Discovery MRFC Multimedia Resource Function Controller MRFP Multimedia Resource Function Processor MS Mobile Station MSC Mobile services Switching Center MT Mobile Terminal P-CSCF Proxy Call Session Control Function PCM Pulse Code Modulation PDF Policy Control Function PDP Packet Data Protocol PEF Policy Enforcement Function PIB Policy Information Base PS Packet Switched PSTN Public Switched Telephone Network QoS Quality of Service RAN Radio Access Network RNC Radio Network Controller Glossary of Acronyms 257 RNS Radio Network Subsystem RTP Real Time Protocol SIP Session Initiation Protocol S-CSCF Serving Call State Control Function SGSN Serving GPRS Support Node SGW Signaling GateWay SLF Subscription Locator Function TDD Time Division Duplexing TDMA Time Division Multiple Access TE Terminal Equipment UE User Equipment UMTS Universal Mobile Telecommunications System UTRAN Universal Terrestrial Radio Access Network VLR Visitor Location Register VMSC Visitor Mobile services Switching Center W-CDMA Wideband Code Division Multiple Access References [1] 3GPP, Vocabulary for 3GPP specifications, TR 21.905, V6.5.0, January 2004. [2] M. Zeng, A. Annamalai and V.K. Bhargava, Harmonization of global third-generation mobile systems, IEEE Communications Magazine, December 2000, 94–104. [3] A. Furuska ¨ r, S. Mazur, F. Mu ¨ ller and H. Olofsson, EDGE: Enhanced Data Rates for GSM and TDMA/136 Evolution, IEEE Personal Communications, June 1999, 56–66. [4] 3GPP, Evolution of 3GPP system, TR 21.902, V6.0.0, September 2003. [5] 3GPP, Services and service capabilities, TS 22.105, V6.2.0, June 2003. [6] 3GPP, Network architecture, TS 23.002, V6.3.0, December 2003. [7] 3GPP General Packet Radio Service (GPRS); Service description; Stage 2, TS 23.060, V6.3.0, December 2003. [8] 3GPP Service requirements for the Internet Protocol (IP) multimedia core network subsystem; Stage 1, TS 22.228, V6.5.0, January 2004. [9] 3GPP IP Multimedia Subsystem (IMS) group management; Stage 1, TS 22.250, V6.0.0, December 2002. [10] 3GPP, Technical realization of Cell Broadcast Service (CBS), TS 23.041, V6.2.0, December 2003. [11] M. Hauge and 1. Kure, Multicast in 3G networks: Employment of existing IP multicast protocols in UMTS, ACM WoWMoM, September 2002, 96–103. [12] 3GPP Multimedia Broadcast/Multicast Service (MBMS); Stage 1, TS 22.146, V6.3.0, January 2004. [13] 3GPP Multimedia Broadcast/Multicast Service (MBMS) user services; Stage 1, TS 22.246, V6.0.0, January 2004. [14] 3GPP IP Multimedia Subsystem (IMS); Stage 2, TS 23.228, V6.4.1, January 2004. [15] J. Rosenberg, H. Schulzrinne, G. Camarillo, A. Johnston, J. Peterson, R. Sparks, M. Handley and E. Schooler, SIP: Session Initiation Protocol, June 2002, RFC 3261. [16] M. Garcia-Martin, E. Henrikson and D. Mills, Private Header (P-Header) extensions to the Session Initiation Protocol (SIP) for the 3rd-Generation Partnership Project (3GPP), January 2003, RFC 3455. [17] M. Handley and V. Jacobson. SDP: Session Description Protocol, April 1998, RFC 2327. [18] K.D. Wong and V.K. Varma, Supporting real-time IP multimedia services in UMTS, IEEE Communications Magazine, November 2003, 148–155. [19] 3GPP Interworking between the IM CN subsystem and IP networks, TS 29.162, V1.0.0, March 2002. [20] 3GPP Interworking between the IP Multimedia (IM) Core Network (CN) subsystem and Circuit Switched (CS) networks, TS 29.163, V6.1.0, December 2003. [21] 3GPP Multimedia Broadcast/Multicast Service (MBMS) user services; Architecture and functional description, TS 23.246, V6.1.0, December 2003. [22] M. Handley, C. Perkins and E. Whelan, Session Announcement Protocol, October 2000, RFC 2974. [23] 3GPP Quality of Service (QoS) concept and architecture, TS 23.107, V6.0.0, December 2003. 258 Wireless Multimedia in 3G networks [24] R. Koodli and M. Puuskari, Supporting packet-data QoS in next-generation cellular networks, IEEE Commu- nications Magazine, February 2001, 180–188. [25] W. Zhuang, Y.S. Gan, K.J. Loh and K.C. Chua, Policy-based QoS architecture in the IP multimedia subsystem of UMTS, IEEE Network, May/June 2003, 51–57. [26] 3GPP End-to-end Quality of Service (QoS) concept and architecture, TS 23.207, V5.3.0, March 2002. [27] K. Chan, J. Seligson, D. Durham, S. Gai, K . McCloghrie, S. Herzog, F. Reichmeyer, R. Yavatkar and A. Smith, COPS usage for Policy Provisioning (COPS-PR), RFC 3084, March 2001. [28] D. Durham, J. Boyle, R. Cohen, S. Herzog, R. Rajan and A. Sastry, The COPS (Common Open Policy Service) Protocol, RFC 2748, January 2000. [29] 3GPP Policy control over Go interface, TS 29.207, V5.7.0, March 2004. [30] 3GPP End-to-end Quality of Service (QoS) signaling flows, TS 29.208, V5.7.0, March 2004. References 259 Part Two Wireless Multimedia Applications and Services 9 Wireless Application Protocol (WAP) Alessandro Andreadis and Giovanni Giambene 9.1 Introduction to the WAP Protocol and Architecture WAP Forum was formed when a USA network operator, Omnipoint, issued a tender for the provision of mobile information services in early 1997. It received several responses from different suppliers using proprietary techniques such as Smart Messaging from Nokia and Handheld Device Markup Language (HDML) from Phone.com. These different approaches were not so different, thus implying that they could be combined and extended to form a powerful standard. Hence, Omnipoint informed the tender responders that it would not accept a proprietary approach and recommended that various vendors got together to explore the definition of a common standard. These events triggered the development of WAP, a standard for delivering Internet contents to wireless devices. Ericsson, Motorola, Nokia and Phone.com founded the Wireless Application Protocol Forum (WAP Forum) in 1997. Hundreds of members joined the WAP forum that, at present, has been consolidated into the Open Mobile Alliance (OMA) [1]. The explosive growth of the Internet has fuelled the creation of new and exciting information services. Most of the original technology developed for Internet services has been designed for large computers with medium-to-high bit-rate transmission capabilities, large displays, a keyboard and a mouse as input devices. Whereas, mobile devices have small displays and are constrained in terms of CPU processing capacity, available memory, energy consumption, displays size and input methods (i.e., there is not a mouse). An interesting approach for allowing the mobile access to the Internet is provided by WAP, a comprehensive and scalable protocol stack designed for use with:  diverse mobile phones: from those with a one-line display to Personal Digital Assistants (PDAs), smart-phones and pagers;  several network bearers, such as: Short Message Service (SMS), Circuit Switched Data (CSD), Unstructured Supplementary Services Data (USSD), General Packet Radio Service (GPRS), etc.;  many mobile network standards, like: GSM 900, 1800 and 1900 MHz; Interim Standard (IS)-136; Digital European Cordless communication (DECT); Trans European Trunked RAdio (TETRA); third-generation (3G) cellular systems; Emerging Wireless Multimedia: Services and Technologies Edited by A. Salkintzis and N. Passas # 2005 John Wiley & Sons, Ltd  different operating systems, like: Windows CE, PalmOS, EPOC, Pocket PC, FLEXOS, OS/9, Linux and JavaOS. Two main releases of the WAP protocol standard have been issued, namely WAP 1.X (with many variants, being WAP 1.2 the most significant one among them [2]) and WAP 2.0. The WAP 1.X network architecture envisages WAP servers, hosting pages designed in the Wireless Markup Language (WML), and WAP gateways between the wireless network domain and the wireline Internet. The WML language (an eXtensible Markup Language a [3]) is specifically conceived for small screens and one-hand navigation without a keyboard. WML is scalable from two-line text displays up to graphic screens of smart phones and communicators. WAP also defines a markup script language, WMLScript, similar to JavaScript, but making minimal demands on memory and CPU power. At the application layer, WAP specifications define a Wireless Application Environment (WAE) aimed at enabling operators, manufacturers, and content developers to built advanced services and applications including a micro-browser (to display WML pages), scripting facilities, e-mail, World Wide Web (WWW)-to-mobile-handset messaging, and mobile-to-telefax access. Pages in WML are called decks. Decks are constructed according to a set of cards. WAP contents are transported by using a set of standard communication protocols based on the Internet protocol suite. Moreover, WAP adopts a proxy approach (Performance-Enhancing Proxy, PEP) to improve the inter-connection between the wireless domain and the Internet. In particular, the proxy appears like a server towards the mobile user and like a client towards the Internet. The WAP proxy supports the following functionalities.  Gateway. It performs the adaptation from the WAP protocol stack to the WWW protocol stack and vice versa.  Coding and decoding. A binary encoding process is employed to make the contents more compact and suitable for transmission through the wireless link.  Caching proxy. A caching proxy can improve both the access performance and the network utilization by maintaining a cache of frequently accessed resources. WAP puts the intelligence in the WAP proxy&gateway, whilst adding just a micro-browser to the mobile phones, requiring only limited resources on the mobile phone. The following two cases are possible for the contents retrieved from the Internet. (1) The Web server provides contents in the HyperText Markup Language (HTML) format: the proxy has to translate this information in WML format. (2) The Web server directly provides WAP contents in WML format: the proxy doesn’t have to perform any filtering action. The WML compact format is further encoded by the proxy in a binary compressed representation, optimized for the transmission on the low-bandwidth links of the radio mobile network. WAP version 1.2 has introduced new features such as: push services (proactive delivery of information from a WAP gateway to a WAP terminal), user profiles, WMLScript, CryptoLibrary, Wireless Telephony Application (WTA), WAE enhancements and other features. On the basis of the WAP architecture described in Figure 9.1, WAP operates as follows. (1) The user requests a Web page with a given Uniform Resource Locator (URL). (2) The user agent sends a URL request to a WAP gateway by means of the WAP protocol (i.e., through WSP/WTP protocols that are described in the following sub-Sections 9.2.2 and 9.2.3). a XML is a language proposed by the World Wide Web Consortium (W3C) in 1998 to allow data exchanges between heterogeneous systems. An XML document can be used to store and to transfer information in a form completely independent of both the platform and the device. 264 Wireless Application Protocol (WAP) (3) The WAP gateway creates a conventional HTTP request for the specified URL and sends it to the Web server. (4) The HTTP request is processed by the Web server. The URL may refer to a static file or to a script application. In the first case, the Web server fetches the file and adds an HTTP header to it. If the URL specifies a script application, the Web server runs the application. (5) The Web server returns the WML page (i.e., a deck; see subsection 9.3.1) with the added HTTP header or the WML output from the script application. (6) The WAP gateway verifies the HTTP header and the WML content and encodes them into a binary format that is delivered to the user agent. (7) The user agent receives the WAP response. It processes the WML response and displays the first card of the WML deck to the user. In 2002, WAP Forum released the 2.0 version of the WAP Protocol. WAP 2.0 gets the wireless world closer to the Internet with a new suite of specifications. The access to the Internet through wireless devices is more similar to the access by means of a fixed terminal [4]. WAP 2.0 is based on the latest Internet standards: the WML2 markup language derived from the eXtensible HyperText Markup Language (XHTML), a wirelessly-optimized TCP/IP suite and the HyperText Transfer Protocol (HTTP/ 1.1). XHTML provides the ability to make graphical Web pages, similarly to common Web pages, but in a smaller size [5]. The wirelessly-profiled TCP and HTTP are optimized versions of the Internet TCP and HTTP protocols for a more efficient delivery of the contents over wireless links. In the previous versions of the WAP standard a WAP gateway was needed in order to establish a connection between a mobile client and a server in the Internet (the WAP protocol was employed for the dialogue between the mobile client and the gateway; standard Internet protocols were used for the dialogue between the gateway and the server). Whereas, WAP 2.0 does not need a gateway since the communication between the client and the server is direct by means of the HTTP/1.1 protocol. However, a WAP proxy is still useful to cache frequently accessed Web pages and to provide the mobile terminal with localization, user privacy, push services and service personalization (the proxy communicates mobile phone capabilities to the application so that contents can be customized for a particular device). In addition to the classical WAP architecture with Web server, WAP proxy and WAP client, other configurations can also be supported by release 2.0. In particular, we can consider supporting servers that provide useful functions for devices, proxies, and application servers. Examples of supporting servers are as follows.  PKI (Public Key Infrastructure) Portal. The PKI portal allows devices to initiate the creation of new public key certificates [6].  UAProf Server. The UAProf server allows applications to retrieve client capabilities and profiles of user agents and individual users [7]. CC/PP 1.0 is a standard for expressing device capabilities and user preferences by means of the Resource Description Framework (RDF) [7].  Provisioning Server. The provisioning server is trusted by the WAP device to give its provisioning information [8]. Web Server Content CGI Scripts etc. WML Decks with WML-Script WAP Gateway WML Encoder WMLScript Compiler Protocol Adapters Client WML WML- Script WTAI Etc. HTTPWSP/WTP 1 7 6 2 5 3 4 Figure 9.1 WAP basic architecture. Introduction to the WAP Protocol and Architecture 265 [...]... client device, derived from JavaScript and optimized for low-bandwidth communication and thin clients, like cellular phones and WAP Languages and Design Tools 277 Figure 9.11 WML document (deck) structured in cards pagers It is part of WAE and it is used to complement WML, to overcome its limitations and to extend its capabilities by adding intelligence to the client and reducing the overall network traffic... development and execution of applications and services targeted at a wide variety of wireless platforms The main goals of WAE are to provide an application framework that is neutral to the network and is particularly suitable to narrow-band wireless devices, permitting a high degree of device independence It adopts a Web programming model, leveraging on Internet standard technologies Wireless Application... IP IP Wireless bearers GSM IS-136 TETRA DECT 3G Etc Data link layer Physical layer Figure 9.3 WAP and Web protocol stacks WAE enables WAP devices, generally assumed to have restricted input capabilities, small display size and limited bandwidth requirements, to access services and applications in an efficient manner WAE allows the creation of systems and services that are specifically tailored for wireless. .. of display size and graphics, input capabilities, network bandwidth and processing power In particular, the small screen of a typical WAP device does b XSLT is a W3C language and the most important part of the XSL standards It is the part of XSL that is used to transform an XML document into another XML document, or another type of document that is recognized by a browser, like HTML and XHTML WAP Service... Experimented and Implemented WAP Services 2 87 businessmen, brokers, etc.) Below here we give a short survey of WAP-based information services that have been envisaged in some EU projects, both in the ‘tourism area’ and in the ‘systems and services for the citizen area’ [36] Tourism Area CReation of User-friendly Mobile services PErsonalized for Tourism (CRUMPET), to allow for:  personalizing services. .. ftp://ftp.isi.edu/in-notes/rfc2104.txt [15] Wireless Application Protocol Forum, Ltd, Wireless Transport Layer Security, WAP-261, April 6, 2001 [16] Wireless Application Protocol Forum, Ltd, Wireless Datagram Protocol, WAP-259, June 14, 2001 [ 17] Wireless Application Protocol Forum, Ltd, Wireless Control Message Protocol, WAP-202, June 24, 2001 [18] Wireless Application Protocol Forum, Ltd, Wireless Markup Language,... ICC2001, June 2001 [32] A Andreadis, G Benelli, G Giambene and B Marzucchi, Analysis of the WAP protocol over SMS in GSM networks, Journal on Wireless Communications and Mobile Computing, John Wiley & Sons, 1, 381–395, 2001 [33] A Andreadis, G Benelli, G Giambene and F Petiti, Analysis of Downlink Scheduling for Web Traffics in 2G and 2.5G Mobile Networks, Proc of PIMRC 2002, pp 79 4 79 8, Lisbon, Portugal,... functionalities can be modified and finally the server may accept or refuse the session establishment WSP semantics and mechanisms are based on HTTP/1.1, with enhancements and optimizations for wireless networks WSP can be considered as a binary form of HTTP: server and client transmit data in a binary form and this allows one to overcome some limits related to narrow-band mobile networks and to connection-loss... Definition of OSI Services, ISO/IEC 1 073 1, 1994 [12] Wireless Application Protocol Forum, Ltd, Wireless Transaction Protocol, WAP-224-WTP, July 10, 2001 [13] W Stallings, Cryptography and Network Security: Principle and Practice, 2nd edn, Upper Saddle River, NJ, Prentice Hall, 1999 [14] H Krawczyk, M Bellare and R Canetti, HMAC: Keyed-Hashing for Message Authentication, IETF RFC 2104, February 19 97, ftp://ftp.isi.edu/in-notes/rfc2104.txt... Reuters Wireless Services One of the most important issues to be considered when designing WAP services is how to provide contents in a usable form to multiple disparate clients XML and its associated technologies provide a solution to achieve such a goal by supporting different types of devices Actually, XML defines a technology to create documents and to store information in a structured way and it . signaling flows, TS 29.208, V5 .7. 0, March 2004. References 259 Part Two Wireless Multimedia Applications and Services 9 Wireless Application Protocol (WAP) Alessandro Andreadis and Giovanni Giambene 9.1. 2003, RFC 3455. [ 17] M. Handley and V. Jacobson. SDP: Session Description Protocol, April 1998, RFC 23 27. [18] K.D. Wong and V.K. Varma, Supporting real-time IP multimedia services in UMTS, IEEE. RAdio (TETRA); third-generation (3G) cellular systems; Emerging Wireless Multimedia: Services and Technologies Edited by A. Salkintzis and N. Passas # 2005 John Wiley & Sons, Ltd  different