Providing Web Services over DVB-H Mobile Virtual Web Services

1. Vilas, A.F.; Redondo, R.P.D.; Arias, J.J.P.; Solla, A.G.; Duque, J.G.Consumer Electronics, IEEE Transactions onVolume 53, Issue 2, May 2007 Page(s):644 - 652 Providing Web Services over DVB-H Mobile Virtual Web Services Reporter: 藍元宏 Date: 2009/05/11

2. Outline • Abstract • Introduction • Scenario • Virtual Web Services • Virtual Web Services Over DVB-H • Conclusion

3. Abstract • This paper introduces the experiences in accessing Web Services (WSs) from DVB-H terminals. • This propose to move the complexity from client to the service provider by defining Virtual WSs (VWSs). • Virtualization also gives the possibility of defining QoS-aware services as well as caching-based systems to process the responses of clients more efficiently.

4. Introduction – Web Services • Web Services (WSs) combine the best aspects of component-based development and the Internet. • Web Services are accessed via ubiquitous Web protocols (ex: HTTP) and data formats (ex: XML). • WSDL, UDDI and SOAP are considered the core of this Web Service standards set.

5. Introduction – Web Services Limitation • There are two relevant problems make it difficult to achieve this desirable open framework where flexibility is the key factor to communicate WSs and mobile clients. • On the one hand, and inherently to the WS technology, clients are bound to a concrete service provider at design time. • On the other hand, today’s mobile devices do not support the excessive complexity Mobile Web Services would need to allow changing the provider at run-time.

6. Introduction – Solution • This paper propose to introduce an intermediate virtualization layer between mobile clients and WS providers by usingWS virtualization. • AVirtual WS (VWS) is defined within this intermediate layer as a conceptual service grouping one or more WSs. • Alight client for this heavy virtual WS is delivered to the mobile receivers while the VWS ispublished as a standard WS. • Client solves the complexity problems.

7. Introduction – DVB-H Overview • Regarding to delivering aspects, broadcasting is a highly cost-effective way to reach large audiences. • DVB-H (Digital Video Broadcasting-Handheld) is considered a good candidate for being widely adopted, especially in Europe. • DVB-H is forecast to be accessible by approximately 350 million mobile users by 2008.

8. Introduction – The Advantages of DVB-H • DVB-H is an approved standard by ETSI (European Telecommunications Institute). • DVB-H benefits from existing DVB-T (DVB Terrestrial) infrastructure components, reducing initial investments. • DVB-H is clearly supported by the majority of mobile device manufacturers like Motorola, Nokia, Samsung, LG, BenQ and Sagem

9. Introduction – DVB-H Technology • DVB-H has improved the DVB-T standard to overcome the communication problems derived from the inherent characteristics of small and portable devices. • Time-slicing has been introduced to reduce the average power consumption of the receiver and to enable smooth and seamless frequency handover. • It is incorporated a module of forward error correction for multiprotocol encapsulated data (MPE-FEC, Multiprotocol Encapsulation Forward Error Correction), which enhances the reception in the special conditions of handheld terminals.

10. Introduction – DVB-H and IP Protocol • IPDC (Internet Protocol Datacasting) is what converts DVB-H in an end-to-end broadcast system for delivering any type of digital content and services using IP-based mechanisms. • Download by FLUTE (File deLivery over Unidirectional Transport) and streaming by RTP (Real Time Protocol) respectively. • DVB-H ESG (DVB-H Electronic Service Guide) describes the available IP Datacast services.

11. Introduction - Purpose

12. Scenario

13. Virtual Web Services – Overview • Virtualization is an elegant solution to solve several open problems in WS technologies, like asynchronous invocation, error control, high availability, quality of service, etc. • The binding process in WS technologies, binding at design-time, is an important limitation. • WS virtualization is based on grouping one or more web services inside a unique wrapper, which is then published as a standard web service which called VWS.

14. Virtual Web Services – Architecture Client software Service Provider Who need Services Web Services Virtual Web Services

15. Virtual Web Services – Implementation • Theimplementation of this VWS is virtually defined by the VWSDL document (VWS Definition Language). • VWSDL is an XML-based language which has been defined as a stand-alone language, i.e. not as a WSDL extension. • VWSDL definition is only useful to a VWS engine. • On top of VWSDL, this paper have defined VWSEL (Virtual Web Services Extension Language), which allows the clients to use SOAP-Header elements to add control information which modifies the behavior of the engine.

16. Virtual Web Services – VWSDL & VWSEL Documents }QOS VWSEL }caching

17. Virtual Web Services – Development Cycle

18. Virtual Web Services – Production Cycle

19. Virtual Web Services Over DVB-H • DVB-H standard specifies two ways for broadcasting content by using, respectively, the RTP and FLUTE protocols. • RTP contents are mainly devoted to TV-like broadcasting. • Other binary objects (textual, applications, multimedia, etc.) can be delivered in a data carouselover FLUTE. • Both kinds of contents can be locally accessed by using the information in the ESG.

20. Virtual Web Services Over DVB-H – ESG Generation ←Accessing Information ←Broadcast time ←such as a WSDL

21. Virtual Web Services Over DVB-H

22. Conclusion • This define an intermediate layer between the WS provider and the WS mobile client where virtualization is encapsulated, hiding complexity, availability and location problems to mobile clients. • As complexity resides in the virtual Web Services, we have light clients, more adequate for mobile devices. • By combining virtualization of services (through VWS) and broadcast infrastructures (FLUTE carousel over DVB-H); This paper enable mobile devices to access Web Services through the new open Web.

23. Thanks for your attention!!