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VSAT Technology
VSAT Technology

The VSAT definition - What is VSAT, What are VSATs

The term VSAT is an acronym for Very Small Aperture Terminals. The term was initially a trademark for small earth stations marketed by Telcom General of the USA in the '80's. Today the term is used to describe a family of satellite systems and applications, where the terminal equipment use an antenna with a diameter of less than about 4.5 meters, varying down to about 1.2 meters.

The focus is on VSAT systems and applications that make use of geostationary satellites (GSO). These are satellites placed in the geostationary orbit over the equator of the earth at an altitude of 35 786 km. Satellites that are placed in this orbit appear to "stand still" relative to any position on the earth and thus can be used to implement communication systems using non-tracking antennas.

VSATs are at the lower end of a product line of communication systems used for providing communication services that were traditionally only used for international services between earth stations serving countries. These earth stations typically make use of parabolic antennas with diameters between 7 and 32 meters.

The market for VSAT Applications

VSAT technologies have evolved to the point where VSATs are able to address very effectively most of the connectivity needs of ICT users, from the residential market to through to the corporate market.

VSAT systems have traditionally only seen application within large corporates because of the costs involved. This has been changed substantially since the advent of Direct To Home (DTH) television broadcasting, where it has been shown that VSAT receive only technologies can be applied in the consumer enduser markets. The success of these deployments has been largely due to:

• The development of open standards that have lowered the costs of TVRO terminals
• The launching of GSO satellites utilizing Ku band frequencies that in turn allow the deployment of smaller remote terminals
•  Modern GSO satellites deliver high power spot beams that are able to focus directly on specialized market areas
• The development of multibeam satellites with improved connectivity arrangements

Why VSAT, What are VSAT networks, The demand for VSAT Networks

The users

Any requirement for connectivity in remote areas or areas where other technologies cannot provide services are prime targets for the use of VSAT technologies.
The user list is long and detailed but can be grouped as follows according to the types of ICT services required.

- One-way VSAT services

The delivery of television broadcasting direct to end-user through the use of Direct-to-home (DTH) services is the obvious one that everyone knows about. But there are others and the following list is a sample of where one-way VSAT service are used:

• Stock market and other closed user group information broadcasting
• Distance education and continued education services for large corporate companies
• The distribution of financial analysis services in real time
• The distribution of market information to remote offices located in geographically dispersed locations
• The updating of market related information, the distribution of new product catalogues and pricing information to outlets in the retail industries.
• The distribution of audio broadcasting services in shops and public areas
• The introduction of DAB services even direct to end-users (GlobalStar)
• The distribution of financial analysis services in real time
• The relay of advertising material to shops and direct to electronic signs
• The relay of information to motor vehicle drivers along highways

- One-way VSAT services

By far the most significant applications are those that allow for two-way communication via satellite, especially in areas considered to be rural or so remote that normal ICT services are not possible.
The most extreme examples available are the delivery of modern ICT services to places such as the Antarctic and to shops at sea using two-way VSAT systems. These so-called Earth Stations on Vessels (ESV's) are now able to maintain all the normal services available on land. The demand for ESV services on cruise ships extends to the delivery of:

• Normal voice, fax and data connectivity
• Access to internet services and the WWW
• The provision of connectivity to the cellular industry so that mobile GSM services remain active even on the oceans.

The list below is some of the more traditional applications for two-way VSAT systems.

• Interactive computer transaction services
• Low rate video conferencing
• High rate real time video monitoring services (e.g. the control of undersea diamond mining operations from land based security centres).
• Database enquiry services
• Bank transactions and ATM services in remote locations
• Tourism reservation systems
• Distributed process control systems especially in the oil industries
• Distributed telemetry systems used for monitoring power networks, water management systems, traffic control on highways and disaster monitoring systems
• Voice, data, fax communication services in rural areas
• Telecenters, Cybercafes
• Emergency services
• Electronic funds transfer services direct at point of sale
• E-mail systems
• Medical data transfer and distance or tele-medicine
• Sales monitoring and stock control
• Satellite news gathering services
• The provision of Wide Area Networks (WAN's) and the extension of LAN's to remote locations
• The delivery of interactive multimedia services
• Large ICT networks for embassies

Why VSAT, What are VSAT networks, The demand for VSAT Networks

Now why are VSAT systems able to provide these types of services? The following shows that any ICT service that builds on the inherent strengths of satellite communication systems will benefit from VSAT applications.

The drivers

The main drivers of the VSAT industry are all market related and are there because the market requires needs to be addressed. Some of these drivers are:

• The desire of governments to ensure that all their citizens are able to obtain equivalent ICT services regardless of their geographical location.
• The desire by large corporations for redundant and alternative networks, independent of terrestrial infrastructure.
• The need for connectivity that is always available, regardless of geographical and political constraints.
• The increasing need for high-speed services and multimedia connectivity direct to endusers
• The needs for more and more connectivity


Satellite communication systems have some advantages that can be exploited for the provision of connectivity. These are:

• Costs Insensitive to Distance
• Single Platform service delivery (one-stop-shop)
• Flexibility
• Upgradeable
• Network life cycle costs are lower than some alternatives
• Fast Deployment: Install & Commission: 1/2 - 2 Days
• Reliable Service: 99.9% for Data; 99.5%+ for Voice
• Mean Time Between Failures (MTBF) > 25,000 Hours (3 Years)
• TProven in 100+ Countries
• Unrestricted ubiquitous coverage of large geographical areas by single systems
• Low incremental costs per unit


However like all systems there are disadvantages also. Some of these ares
• High start-up costs (hubs and basic elements must be in place before the services can be provided)
• Lack of adequate coverage in some parts of the world (Africa is the last continent that does not have dedicated GSO satellite bandwidth available that will allow single satellite connectivity anywhere on the continent).
• Higher than normal risk profiles
• Severe regulatory restrictions imposed by countries that prevent VSAT networks and solutions from reaching critical mass and therefore profitability
• Some service quality limitations such the high signal delays (latency)
• Natural availability limits that cannot be mitigated against
• Lack of skills required in the developing world to design, install and maintain satellite communication systems adequately

Some of these limitations and disadvantages are nothing else than opportunities that can be overcome.

Benefits of One-Stop Shop Solutions to customers

VSAT systems and especially the new Internet Protocol Very Small Aperture Terminal (IPVSAT) systems have a trump card at their disposal. VSAT systems have for many years been able to deliver all customers ICT needs from one platform.

Service convergence for voice, fax, data and video has been accomplished. Even convergence between mobile and so-called fixed line services has been achieved within the VSAT industries.

Customers are able to develop a universal set of applications that deliver all their needs on one platform. The benefits are obvious in that overall connectivity costs are lower for similar or comparable ICT networks.

The value derived by end-users

End-users derive value from VSAT networks in a number of ways. Some of these are:

• Lowered overall per unit connectivity costs
• Improved total ICT network performance
• Loss mitigation under network failure conditions
• Improved response times to major business failures because of improved connectivity.
• Increased market share and increased revenues for companies large and small
• Improved provision of essential services by governments especially in remote areas
• Improved quality of life for all the people of a country as a result of increased economic activity
• Improved response to emergency situations as satellite systems can be restored quickly and effectively

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