Integration of Digital Satellite and Terrestrial Networks for Education and Training

Dr Adrian Vranch

Dr John Marshall

University of Plymouth
Plymouth
Devon
United Kingdom

Abstract

The University of Plymouth has developed an integrated digital networking infrastructure for voice, video and data throughout the region to deliver a variety of education and training programmes. This session will describe how the infrastructure has been implemented using a novel combination of ISDN, SWAN (a regional ATM network) and digital MPEG2 satellite broadcasts from the University's uplink. It will discuss cost benefits analysis in terms of low cost, wide access and quality and will describe such uses as research seminars for health care students, across distributed campuses and training of surgeons in the region's hospitals using live, interactive digital satellite TV.

The University of Plymouth is a large institution with over 20,000 students and is engaged in higher education, consultancy and research. The University is located in the South West of England and covers the counties of Cornwall, Devon and Somerset, comprising several campuses separated at its widest point by 300 kilometres of mostly rural area (Figure 1). The University has developed a reputation for the delivery of distance learning courses using telematics technologies, including live, interactive broadcasts from its own TV studio and a TDS4 satellite uplink transmission facility on loan from the European Space Agency (Winders 1993).

These broadcasts offer interactive opportunities through the use of audio conferencing and ISDN video conferencing to enhance the learning experience of remote students. More than 800 live TV programmes have been transmitted since 1989 (Winders & Wheeler, 1997). The University�s Satellite Research Centre has developed a sub-carrier data transmission system, which can deliver computer data at 128 Kbps simultaneously to distributed PCs, each equipped with a data capture card. Each PC capture card has a unique electronic identity, which enables selective transmission of data. This provides a high security facility for delivery of sensitive content and enables course material to be distributed only to bona fide recipients. This technique was originally introduced for wide band FM (analogue) broadcasts, and has recently been developed for transmissions incorporating MPEG2 digital video compression. This results in the cost advantage of reduced satellite rental charges, since as little as one-eighth of the satellite transponder is required (Glover, 1996). In practice, this translates into an 80% reduction in transponder costs, which is a considerable saving.

The use of these satellite transmission techniques combined with computer and communication technologies has enabled the University to pioneer a number of innovative regional, European and global telematics projects. Key projects are illustrated in this paper to demonstrate how these technologies are integrated to provide effective distance learning. The paper describes how the University of Plymouth has played the leading role in establishing a regional network infrastructure in support of its distributed campuses and sites across the counties of Cornwall, Devon and Somerset. In particular, developments in integrating satellite and terrestrial networks are illustrated using the key projects described herein.

There are several issues that must be addressed in order that an effective, integrated regional network infrastructure can be implemented. On the practical level there are technical and physical considerations to be made in providing the services that the users need, but in a situation where the communications technologies available are rapidly changing. At a strategic level, distribution and integration of services must be carefully planned in an environment where regulations that apply to networking connectivity are changing. On the political level, the need for collaboration with key organisations and agencies is a key part of implementation.

The University of Plymouth has strong regional connections with other higher and further education institutions, with health care organisations, local government agencies and with businesses. In addition to the need to support a distributed campus structure it is important for the University to strengthen the links with these other key regional bodies. There are restrictions on connectivity between educational networks and local government or health services networks. This is largely for security reasons to respect personal confidentiality. There are regulations on the SuperJANET educational network, which links universities and higher education institutions, that restrict connectivity to non-educational organisations, such as businesses. Indeed connection to SuperJANET for further education colleges has only recently been allowed. Connection of schools to SuperJANET is not implemented at present. Integration with public networks, for example ISDN must be considered along with alternative networking technologies, for example, satellite TV/data broadcasts.

The University of Plymouth has, for nearly 10 years, enjoyed exclusive access to the TDS4b digital satellite up-link on loan from the European Space Agency. During the last three years additional, valuable experience has been gained in broadcasting MPEG2 digital TV transmissions via Eutelsat W2, the satellite used in the present study, which has a footprint covering Europe and beyond. In the last five years the University of Plymouth has been the lead player in establishing over 35 regional community telematics training centres, along with SWAN, the South West Area Network, which provides a high bandwidth regional educational networking infrastructure (Figure 1).

In addition, the University's Institute of Health Studies has established learning centres for nurse education in the region's hospitals (Vranch and Wheeler, 1997b) although these centres are not connected to SWAN, since this could compromise the security of the NHS network and confidentially of patient records. There are distinct advantages in using live digital satellite technology in terms of its superior audio and visual quality, high security and low transmission costs compared with delivery technologies that use solely terrestrial networks. In particular, delivery of course materials via satellite into hospitals can be achieved without compromising the security of the NHS network, since no network connection is necessary. A return path for interactivity can be made via ISDN2 video conferencing, telephone or fax, again without compromising network security. The video conferencing return path can be used for trainees to ask questions directly to the studio presenters or to bring in an expert lecturer from a remote location as a contributor to the live session. In both cases the video conferencing image appears live as a window within the TV screen.

The following sections describe a number of key projects that illustrate the development of the current regional network infrastructure and give examples of technologies that have been used to provide appropriate services for distance learning.

The WIRE - Mediaspace project delivered a distance learning course in Multimedia to Euro Study Centres in European universities (Vranch et al, 1997). WIRE (Why ISDN in Research and Education?) used a powerful combination of terrestrial and satellite services, including audio and video conferencing, computer mediated communications and electronic mail, to support the learning process. Feedback from students in the use of all these technologies has previously been very positive (Hilton, 1996; Emms and McConnell, 1988; Ackermann, 1996, Huckle, 1996). These studies each used a limited number of combined technologies, unlike WIRE-Mediaspace, which employed several technologies in delivery of one course.

In the WIRE-Mediaspace project, with its focus on ISDN, particular attention was paid to combining ISDN video conferencing, ISDN file transfer and ISDN remote access techniques with the technologies of live satellite TV, WWW server and FirstClass electronic conferencing. The aim of the Mediaspace course was to use these technologies to mirror the functions of firstly the "keynote lecture", and secondly seminar/tutorial support sessions - with the emphasis in both cases on providing interactivity at a distance. This was to be achieved in the former by a series of monthly live satellite broadcasts and in the latter by FirstClass electronic conferencing. This was accompanied by ISDN video conference and remote access and file transfer sessions - especially for the development of joint multimedia projects at a distance. The WWW server provided further links to other relevant Web sites and access to files used in the transmissions for downloading. The use of ISDN video conferencing and FirstClass electronic conferencing into the studio floor aimed to provide two means of communication, in addition to telephone and fax services, to enhance interaction during the programmes. In particular, the use of ISDN video conferencing during the programmes was seen as a means to bring guests and viewers "into the studio" from a distance to contribute to the programmes.

The various aspects of the operational model for WIRE-Mediaspace are illustrated in Figure 2, including the balance between synchronous and asynchronous working and the role of each technology in delivery of learning materials, providing communication and access to information.

The content of Mediaspace (i.e. distance learning in multimedia) was chosen to explore the rich audio-visual nature of the topic and the practical issues of bandwidth requirements to transfer very large multimedia files in the context of using combined technologies. There are benefits in using the relatively high bandwidth offered by ISDN services for file sharing and the audio-visual quality provided by satellite TV transmissions.

RATIO (Rural Area Training and Information Opportunities), was a European-funded project (Wheeler, 1997) aimed at establishing 40 regional telematics centres throughout the Objective 5b area of the South West of England (Figure 1). RATIO aimed to regenerate the economic fortunes of the region and had a particular focus on re-skilling existing SME work forces. RATIO�s telematics learning centres are equipped with digital satellite receivers, desktop ISDN video conferencing, computer-mediated communication and Internet connectivity. In terms of technology infrastructure, these RATIO centres distributed in the community are analogous to Euro Study Centres, based in the universities that received the WIRE-Mediaspace course. The difference between the two was that RATIO centres used digital satellite receivers.

A variety of courses are available through RATIO, covering a range of topics in vocational training and professional updating, including business, management, computing and languages. RATIO courses offer differing approaches to the WIRE-Mediaspace operational model, using different combinations of technologies to deliver specific courses. RATIO has placed more emphasis on using telematics technologies in the area of communication for learning support, assessment and evaluation. Live TV transmissions feature widely in course delivery. In contrast with WIRE-Mediaspace, where few paper materials were used some RATIO courses have put more emphasis on using paper-based learning materials and CAL software located in the centres.

ADAPT through RATIO is a current project funded through the European Social Fund ADAPT Programme and has been set up to develop courses and content for education and training programmes to be delivered at a distance. The RATIO centre infrastructure can be used to deliver these courses.

In the recent reorganisation of education for health care professionals in the UK, the University of Plymouth was awarded the contract for the health care students in the South West region and the Institute of Health Studies was set up. Degree courses and postgraduate awards for nurses, midwives and other health care professionals are delivered to four main sites, i.e.Pool, Plymouth, Exeter and Taunton and to study centres in eight hospitals in the region (Figure 1). The four main sites are connected to the SWAN network but the hospital study centres are not due to restrictions in connectivity. All twelve centres can receive digital TV broadcasts and this technology is used to provide a series of research seminars for nursing students. Interaction and feedback in the live sessions is enabled using telephone dial-in.

With the current development of high quality video conferencing over the SWAN network, feeds to studio can be taken from any of these four main sites for integration into the live transmission. This enables guest lectures from these sites to contribute without travelling. In addition ISDN2 or ISDN6 feeds can enable guest lecturers from other organisations to participate from a distance. The integrated set-up is shown in Figure 3.

Interest has been shown outside the region and students at the University of Hull, at a distance of over 500 km from Plymouth, are now participating in these research seminars.

Euronet is another current ADAPT Programme project, in which the University of Plymouth is a partner. The partners in Euronet are distributed throughout the UK, in Wales, North East England and East Anglia. One aspect of Euronet is to explore the potential for inter-regional distance training using a variety of technologies. In a live programme in July 1999, an ISDN2 feed was taken from the University of Hull via a video conferencing bridge and transmitted from the Plymouth studio. The use of ISDN2 limited the quality of the video that was broadcast but the interaction in the progrramme was good.

A more ambitious session was broadcast to Euronet partners, RATIO centres and other venues (Figure 5) in October 1990. The programme, sponsored by the Department of Trade and Industry, formed part of the dissemination process for the UK Information Society Initiative. Live ISDN6 video conferencing feeds were taken from Pendle, London, Cardiff and Birmingham, where guest speakers were located, with audiences from businesses. Guests in the TV studio could interact with participants at these four main sites via video conferencing. In addition, viewers from other sites could ask questions via telephone and e-mail. The quality of the ISDN6 feed was much more satisfactory than the ISDN2 feed in the earlier broadcast.

Training surgeons in rural hospitals can be problematic, due to the costs and travel time involved (Dawson, 1998, Bunch et al., 1998). When surgical trainees spend time away from the surgical area to attend lectures and seminars other practitioners must fill the gap. Distance learning delivery using telematics was seen to provide a possible answer to these problems. The South & West Region of England covers a large geographical area with 3.5 hours travelling time between its remotest hospitals. There are over 300 basic surgical trainees studying in the 14 teaching hospitals. There is therefore a very strong case on practical and economical grounds to explore the potential for providing surgical education in the region using distance learning technologies, enabling surgical trainees to remain within their work environment whilst continuing their studies.

The TETRASUR initiative was set up to evaluate the use of distance learning technologies for delivery of the MRCS course to trainees working in hospitals. The TETRASUR course includes lectures, case presentations and interactive discussions by ISDN2 video-conference and satellite TV links. The course is supported by 140 tutors and teachers from the South & West Region in England with over 300 surgical trainees participating in 6 of the 14 teaching and district general hospitals in 3 counties in South West England. Since September 1997, 42 modules have been successfully delivered from Plymouth. At the beginning of the 1999 academic year, satellite and video conferencing links were being established outside the region in Dartford, Kent and at the Royal College of Surgeons, London, with further links planned elsewhere in the UK.

Efforts have been made to decentralise the delivery of the TETRASUR lectures by bringing in more contributions from external sites. Bearing in mind the limitations of ISDN2 for video quality, this development has prompted the exploration of alternatives to ISDN2 for this type of remote feed. For example, trials are planned in the 1999 to evaluate the use of ISDN6 and other high bandwidth terrestrial networks (Figure 6) to establish what network solution provides acceptable quality of video and sound for external content feeds. This will be surveyed from the perception of trainees, Surgical Tutors and lecturers to establish what is acceptable. These trials will explore the potential to use managed bandwidth over the SuperJANET educational network, within the security limitations of connectivity restrictions between educational and NHS networks.

As a result of experiences in WIRE-Mediaspace and RATIO an attempt was made to visualise the various parameters that contribute to the successful delivery of distance learning courses (Vranch and Wheeler, 1997). It is important to select appropriate technologies that are affordable, accessible and match the end-users’ perception and expectation of quality of content.

The Benefits Analysis Map is an attempt to quantify three parameters: High Quality, Wide Access and Low Cost for delivery of distance learning via a single technology or via a combination of technologies and networks. This is intended as an aid in deciding which technologies are appropriate in delivery of a particular distance learning course. The approach is at first student-centred in that the three parameters are considered from the student perception of the distance learning experience. However the approach can also be applied equally to consideration of the three parameters from the viewpoint of the course provider.

The example in Figure 7 shows the three parameters arranged in a triangle with a specified target minimum requirement zone (dotted line) and an example solution (unbroken line) plotted. Distances are measured from the centre, O, such that the distance OQ represents the extent to which the parameter High Quality has been met. The longer the distance OQ, the closer the solution meets the condition of 100% High Quality. Similarly, the distances OA and OC represent the extent to which 100% Wide Access and 100% Low Cost are being achieved. The example plot must fall outside the target minimum requirement zone to meet all three parameters. In Figure 7, the example achieves the required level of Wide Access and Low Cost but fails to meet the requirement of High Quality. In practice, this simple example could represent the delivery of multimedia course content in 10 minutes via a 28.8 Kbps modem to a user in the UK. Equipment costs (user and provider) and line charges are relatively low, access to a telephone line is wide but the modem bandwidth is not adequate to deliver the large files within the time period required.

The projects described above have provided valuable experience in the integration of computer technologies and networks to deliver distance learning courses. The WIRE-Mediaspace live satellite TV transmissions enabled the quality of video and audio content appropriate to a course in multimedia to be received at a distance. The content of the transmissions formed a large part of the learning materials in the course. Interaction, via telephone, ISDN video conferencing or computer mediated conferencing/electronic mail, took place at one time or another to bring in expert guests and for student questions. As the series progressed it was interesting to note that students moved away from video conferencing as a means to ask questions and more towards electronic mail. As Dooley points out, frequency of e-mail use increases in direct relation to cognitive demands of the work (Dooley, 1996). E-mail was seen as a means to maximise interaction while minimising interruption, since the electronic mail interaction could take place unobtrusively during the live programme. On the other hand, integration of guest speakers was best achieved via ISDN2 video conferencing, although the quality of video and sound were noticeably inferior compared with satellite television quality.

These considerations demonstrate the range of network infrastructure options that can enable interaction. They also illustrate the advantages of using a combination of technologies via terrestrial and satellite networks to enable users to interact using appropriate modes. Although Euro Study Centres are equipped with standard facilities (for satellite reception, ISDN video conferencing and Internet access) the option to interact from a range of technologies is important to deliver distance learning into regions that have varying levels of network infrastructure available. The nature of the WIRE project, with its focus on ISDN, precluded the use of the data carrier to deliver learning materials at 128 Kbps (i.e. up to 50 Mbytes of data during a one hour programme). Clearly, this facility can be an advantage for regions with inadequate terrestrial networks or where data transfer with high security is required.

One issue that emerged from WIRE-Mediaspace was that of bandwidth available for both send and return functions. The broadcast nature of the TV programmes was ideal for sending high quality video that comprised a major part of the course materials. Similarly, ISDN2 and low bandwidth terrestrial networks for electronic mail communication were adequate for effective return feedback and questions, although the limitations of ISDN2 were noticed when guest experts were delivering content via video conferencing. The problem of limited two-way bandwidth was highlighted when students needed to collaborate on joint multimedia projects. High bandwidth communications in both directions are essential in this case to facilitate transfer of large multimedia files in a collaborative project.

RATIO has illustrated the importance of good communications and interaction between staff working at remote centres on administration, training and technical support levels. In particular, video conferencing (for meetings) and TV broadcasts (for staff training, marketing) have been important in this respect. With the scale of numbers (40) and dispersion of the RATIO centres it is important to develop a community spirit among staff in the team. RATIO centres are all equipped with MPEG2 digital satellite receivers. This offers the advantage of operation at lower transponder costs compared with broadband analogue (FM) transmission. Digital satellite receive equipment is not widely installed at present, making the potential audience outside of RATIO small, however this may be an advantage in terms of exclusivity of course content on a course fee charging basis.

The importance of practical, organisational issues has been demonstrated in the implementation of the TETRASUR initiative. Synchronisation of release of trainees so that they are available on the same day of the week for the interactive sessions was not an easy task at first, bearing in mind that these trainees were based in several hospitals across the region,. However, the nature of the interactive delivery directly into the workplace made this easier to achieve. Since the trainees were still on site while attending the TETRASUR sessions, permission for release was more readily obtained from management. Savings in travel time could also be more efficiently used as additional study time. The fact that the Institute of Health Studies telematics centres set up by the University in hospitals for distance education for nurses have been made available to doctors on the MRCS course demonstrates a clear commitment to multi-professional working. Indeed, the technology itself has been a key factor in encouraging a multi-disciplinary working culture. Clearly, the delivery infrastructure and approach adopted for TETRASUR can be used to deliver other courses to hospitals.

Evaluation of the TETRASUR project has consisted of post-course interviews with trainees to obtain levels of satisfaction. Generally, feedback from the trainee groups has proved very positive. The fact that the live, interactive TV sessions were an "event" was seen as an advantage by the trainees and was seen as a welcome opportunity to study within the constraints of their demanding work schedule. Trainees valued the opportunity to interact with national and international experts in the field of study who presented the lectures from the Plymouth studio. The TETRASUR approach also encouraged interaction within the trainee groups, both between hospitals and within hospitals. Again, the live "event" helped to bring individuals together as a group. By their own admission, trainees identified that their Information and Communication Technology skills were not advanced and the use of live TV with video conferencing enabled them to benefit from the live sessions, despite their limited ICT experience.

Several areas of concern were raised. Firstly, trainees commented that although they were supportive of the delivery technology, there were a few shortcomings. In particular, technical issues were identified with ISDN2 videoconferencing, relating to inferior visual quality and time lag. Trainees also suggested that presenters should intersperse their talks with question and answer sections to enhance the interactive nature of the lectures. Finally, trainees indicated that introductory lecture material need not be delivered, as the STEP course manuals provided this input. All of the above comments have been taken into consideration in the planning for the 1999 academic year.

The use of ISDN6 external video conferencing feeds has demonstrated the importance of the quality aspect in the cost benefits analysis for business and medical training applications. Access to Health Service networks may pose a problem for the use of SuperJANET to provide feeds at bandwidths greater than 384 Kbps. Nevertheless trials are expected to go ahead with a 2 Mbps link over SuperJANET to enable a comparison with the ISDN6 trials. It is hoped to connect the three main hospitals in the region to the SWAN network, therefore providing very high bandwidth feeds to the TV studio for the TETRASUR transmissions.

The ISDN6 / SuperJANET connectivity to the Plymouth TV studio and TDS4b uplink has potential to provide a national resource for education and this is being explored. Transponder charges and digital decoder costs (Figure 8) have changed considerably over the last eight years and this has affected the balance in terms of the cost benefits analysis. At current prices, all three parameters, i.e. quality, access and cost, are favourable.

In a wider context new networking and ICT technologies are being introduced that must be considered for inclusion in an integrated approach. For example the potential introduction of ADSL (Asynchronous Digital Subscriber Loop) technology in the UK offers some attractions to distance learning delivery. ADSL provides an asymmetric bandwidth of, for example, 4 Mbps with a return bandwidth of 64 Kbps on existing twisted-pair copper telephone lines (Negroponte, 1995). Again, applying the Benefits Analysis Map to ADSL in the UK identifies the advantage of wide availability of telephone network infrastructure and good quality video reception at the user end. As with WIRE-Mediaspace use of the return line may be acceptable for student interaction with a live lecture via e-mail but may not be of high enough quality to enable a lecturer to deliver from a distance. Again, there is the issue of centralised broadcast with an appropriate level of decentralised interaction and contribution.

Costs of ADSL connection in the UK are presently expected to be at least as much as ISDN2. More importantly, the costs and access to ADSL technology to potential providers may be prohibitive. Whereas it is straightforward for individuals and institutions to set up World Wide Web servers, use educational networks and even access satellite uplink facilities, there may be limitations in delivery of courses via ADSL. ADSL is not an attractive technology in countries that do not have an extensive telephone network infrastructure.

As new technologies develop, the opportunities to combine them for multi-mode delivery open up, thus widening the potential number of users that can receive courses. For example, the combination of satellite and cable networks was implemented in WIRE-Mediaspace to extend the reach of the programmes to homes in Finland. Combined satellite and ADSL networks would widen access to users in countries with widely differing network infrastructures.

The potential contribution of VSAT (Very Small Aperture Terminal) technology is worthy of consideration. VSATs such as the TDS4b uplink at the University of Plymouth are satellite transmit systems. As costs of VSATs fall so their potential contribution in an integrated satellite/terrestrial network becomes more important. In particular VSATs can provide very high bandwidth, two-way communication - the very requirement that is the stumbling block for several applications discussed above. Again, the potential advantages of multi-mode delivery systems if they include VSAT technology for a high bandwidth return facility will be substantial.

Technologies for distance learning are developing fast, especially in delivery systems and learning support network infrastructures. In order to achieve the required levels of Quality, Access and Cost that users and providers expect, it is likely that solutions for delivery of distance learning courses will involve an appropriate combination of computer and network technologies. In particular it seems likely that a combination of satellite and terrestrial networks will be a key factor in the delivery of effective distance learning courses.

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The support for the work described in this paper from the following organisations is gratefully acknowledged:

Dr Adrian Vranch
Academic Developments Manager
Academic and Information Services
University of Plymouth
Babbage Building
Drake Circus
Plymouth PL4 8AA
Tel: +(44) 1752 233908
Fax: +(44) 1752 233919
E-mail: [email protected]

Figure 2. WIRE - Mediaspace: integrated technologies for distance learning

Figure 3. Schematic for telematics delivery: IHS research seminars

Figure 4. Schematic for telematics delivery: Euronet Transmission, July 1999

Figure 5. Schematic for telematics delivery: Euronet/DTI Transmission, October 1999

Figure 6. Schematic for telematics delivery: TETRASUR high bandwidth feed

Figure 7. Cost benefits analysis map

Figure 8. Changes in satellite transponder charges and decoder costs