TELDE: Tele Education for Development

Transcription

1 TELDE: Tele Education for Development Authors: Miguel Ferrando, Universidad Politécnica de Valencia, Vicent M. Rodrigo, Universidad Politécnica de Valencia, Carlos Turró, Universidad Politécnica de Valencia, Manuel Jiménez; Universidad Politécnica de Valencia, Mariano Baquero, Universidad Politécnica de Valencia, Alejandro Valero, Universidad Politécnica de Valencia, Abstract. The TELDE project is an initiative of the five public universities in the Valencia Regional Community (Spain), which are associated to develop international cooperation programs jointly. The network of universities is working cocoordinately using the newest technologies of data broadcasting through Spanish satellite Hispasat, covering all countries in Latin America.The system consists of broadcasting compressed audio and video over networks, using Internet protocols and a wide bandwidth. The system is interactive, having the return channel through Internet. A network of 10 university centers in Latin America will be the first places to benefit from the university and postgraduate courses developed by the Valencia university network. The initial network deployment can be gradually expanded with the aid of Non-Governmental Organizations, proposing specific training programs, from professional training to post graduate or doctorate courses. The initial stage will serve 12 receiving centers in Cuba, Nicaragua, Colombia, Uruguay, Costa Rica, Argentina, Peru and El Salvador. Index Terms Cooperation Programs, Streaming Media, Satellites, Latin America. INTRODUCTION The purpose of this paper is to illustrate the TELDE (TELe-education for Development) Project [1]. This paper presents the architecture and the network configuration of a satellite network that can efficiently support broadband interactive multimedia applications, such as tele-learning, and some examples of courses. NETWORK OF UNIVERSITIES The Universities within the Project are: Universidad Politécnica de Valencia, Universidad de Valencia, Universidad de Alicante, Universidad Jaime I, Universidad Miguel Hernández and 12 Latin American Universities from Cuba, Nicaragua, Colombia, Uruguay, Costa Rica, Argentina, Peru and El Salvador. OVERALL SYSTEM ARCHITECTURE The overall architecture of the tele-learning system consists of three core sub-systems: the contents producers, the network (terrestrial and satellite), and a number of distant learners located within the satellite broadcasting area. All educational applications (in the form of IP data) are multiplexed into several DVB-satellite streams and broadcasted, via the DVBsatellite to all receivers in Latin America. Each active learner, receives the broadcasts (via the Hispasat satellite), and can subsequently issue any request for services provision either via a internet terrestrial link. The bandwidth necessary for the application is 500 kbits/s, one-way. It is accomplished using a Broad-Band Regional Network, and Hispasat Satellite System [2]. The receivers are based on PC technology and Digital Video Broadcast antennas. HISPASAT SATELLITE SYSTEM HISPASAT is the satellite system that provides the best coverage over Spain and Portugal. From its orbital position of 30º West above the Atlantic anc close to the Brazilian coast, it provides transatlantic capacity, simultaneously covering all the Latin American countries. The Multi-mission Satellite System consists of a fleet of four satellites (HISPASAT 1A, 1B, 1C and 1D), and a Satellite Control Center, located Arganda del Rey (Madrid). The orbital position of the three satellites is 30º 1

2 West, where they are maintained in the same window. The HISPASAT system's transponders are transparent using both digital and analogue links. IP MULTIMEDIA BROADCASTING The satellite is a telecommunications system with great advantages for broadcasting and multi-distribution. Data can be scattered in the same way as TV programs are currently being transmitted. The multicast technique uses IP as its network protocol. IP multicast (IP-M) is an extension of the IP protocol. This extension enables a single transmission to reach a specific group of users. IP Multicast is an efficient tool for distributing data to a large number of remote sites. Satellites are broadcast oriented. A satellite-based solution can overcome the inconveniences imposed by terrestrial networks regarding the necessary bandwidth. In the fig. 3, the Global Connectivity, from European Research Networks [3] shows the lack of Broadband Networks in the south. DISTANT LEARNER S CONFIGURATION The configuration of an learner is depicted in Figure 4. It is a PC based machine equipped with a DVB-data compliant reception card and one internet connexion, The DVB-data reception card receives the broadcasts via an antenna, demodulates it and produces the appropriate IP data onto the dedicated PC's internal bus. This dedicated PC, which is running under the MS Windows operating system. The software configuration is quite simple: Internet Explorer (version 6) and Windows Media Player (version 9), the application sends two video streams [4]. The fig. 5 shows a sample course. ACKNOWLEDGEMENT This project has been funded by the Agencia Valenciana de Cooperación al Desarrollo, Generalitat Valenciana. REFERENCES [1] The TELDE Project. [2] Hispasat Satellite System. [3] Geant Network. [4] Microsoft Windows Media: 2

3 FIGURES AND TABLES FIGURE. 1 SYSTEM ARCHITECTURE FIGURE 2. HISPASAT SATELLITE EUROPEAN AND AMERICAN FOOTPRINTS. 3

4 FIGURE 3. BROADBAND GLOBAL CONECTIVITY, AUGUST 2002 FIGURE. 4 DISTANT LEARNER S CONFIGURATION 4

5 FIGURE. 5 RECEIVING THE VIDEO STREAMS 5