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Issue 5: Current Developments

Learning without Boundary: Application of Satellite Communication System on Distance Education


Satellites are Appropriate for Distance Education

The purpose of distance education is to provide more access to education for people, especially people who live in the remote areas. Thus, distance education needs a network that enables it to have wide coverage and be interactive providing students and instructors opportunities for real-time communication. Distance education also requires a network, which has broadband capability, so that the network is able to carry large amount of video and audio data. "Satellite distribution can facilitate two-way transmission of dense data traffic at speeds equal to or faster than most wire-based systems."[5] In addition to the synchronous model, distance education provides the asynchronous model for learning.

The asynchronous model allows students to ask questions via email or request instructional materials on the website anytime. Thus, distance education needs a network that has a storage and forward capability.

Although there are some terrestrial systems that provide broadband transmission, such as cable modem and DSL, these systems are not available everywhere even within the same city. When the terrestrial communication networks in the remote area are not well-established, then high-speed data could not be delivered to that area. Through satellite, remote areas have a chance to receive distance education, because satellites have the freedom and mobility of wireless.[6]

USPNet Case

A satellite-based computer network called USPNet-2000 deliver education through distance education to students living in the remote Pacific islands.[7] USPNet-2000 is a VSAT System communication network of University of the Southern Pacific (USP), which founded by the government of Japan, New Zealand, and Australia, together with the USP member countries, such as Lautoka (Fiji), Cook Islands, Solomon Islands, Tonga, and Vanuatu.[8]

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Figure 1: USPNet Networks (Source: USPNet webpage)

The central station is the main campus in Suva, Fiji; it is the hub of this VSAT communication network. The remote campuses are equipped with VAST terminals shown as figure 1,[9] so that they can receive live video lecture from main campus and have synchronous conversation with teachers at the main campus.

This USPNet network provides an efficient communication for the distance education of the University of the South Pacific and its remote campus.

Taiwan Case

Taiwan is another case that successfully delivers education through communication satellite. Unlike USPNet network which utilizes communication satellite to deliver education for remote islands, Application of communication satellite on distance education in Taiwan is mainly to deliver synchronous education for schools in rural areas. Due to the lack of qualified teachers and teaching resources in some rural areas, Ministry of Education the initiated cooperation with cable TV provider, ERA Digital Media (IDTV), to broadcast English learning through communication satellite for elementary school students in rural areas in July, 2002. ERA Digital Media is the major provider of digital video through communication satellite.[10] In this project, 57 elementary schools in rural areas were equipped with satellite dish as a receiver so that students in different regions can receive a synchronous, interactive distance education at the same time.[11]

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Figure 2: IDTV Digital Media Network (Source: IDTV webpage)

In IDTV's network, the instructional video and audio materials are broadcast through communication satellite to individual schools in different counties. Each school receives the materials by satellite dish and then distributes the materials to the computers in individual classrooms through the on-campus internet.

Students can have interaction with the teacher who is in the instructional center at the same times. Figure 2 shows how IDTV network deliver video and audio data.[12] This helps students who are in any corner of Taiwan have equal learning opportunity.

Distance Learning System and Satellite Network

The application of satellites to distance education provides several different communication configurations such as one-way video, one-way video and two-way audio, two-way audio, narrow-band transmission for graphics, and two-way video.[13] These systems represent ways of meeting the different needs of distance education, for example, ways to improve two-way communication to facilitate interaction between students and teachers. The following satellite communication systems represent two-way communication.

VSAT System

This approach provides for the example of two-way audio, video and data. "VSAT is general assumed to be the remote terminal in a dedicated data network based on the star configuration.

As shown in Figure 3, "VSAT system comprises a hub earth station, with a larger aperture antenna, controlling a cluster of VSATs, with small antennas, typically in the range 0.45to 2 meters (m) diameter."[14]

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Figure 3: VSAT configuration

By bringing the corporate VSAT business data system into the distance education sector, the VSAT infrastructure will be able to deliver computer files from the teacher-centered station to the individual learning-centered stations. Instructors and students within this system are also able to see and hear each other. In addition, this system can be used for uploading and downloading materials through the same channel. It provides both on-line (real time) and off-line (asynchronous) interaction between instructors and students.[15]

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