Tuesday, 5 July 2011

What is a VSAT system?

The use of VSAT systems is growing throughout the world as a way of establishing private satellite communications networks for large organisations that have several widely dispersed locations,
or providing higher bandwidth for the individual. Depending on bandwidth requirement (data speed and/or communications channels), VSAT systems can be relatively small (1 - 2 metre antenna) and easily
installed. By linking VSAT terminals to larger hub stations (or land earth stations), a network can be established inexpensively, although in this type of configuration, VSATs can communicate only via the hub and not from remote terminal to remote terminal. This configuration is called STAR configuration. VSAT networks
can readily be configured so that the hub can broadcast data to all the VSAT terminals at higher rates than they can communicate to the hub.
VSAT topologies

As specialists in satellite communications systems,
VSATplus can offer the design and installation of VSAT (Very Small Aperture Terminal) systems.
These provide dedicated, reliable, cost effective and private communications
links for the individual and corporate users, with the provision of total
system capabilities to support high bandwidth secure data, voice and video communication.

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How does a VSAT work?

A VSAT network has three components:
A central hub (also called a master earth station)
The satellite
A virtually unlimited number of VSAT earth stations in various locations - across a country or continent

Content originates at the hub, which features a very large -15 to 36-foot (4,5 -11m)- antenna.
The hub controls the network through a network management system (NMS) server,
which allows a network operator to monitor and control all components of the network.
The NMS operator can view, modify and download individual configuration information to the individual VSATs.

Outbound information (from the hub to the VSATs) is sent up to the communications satellite's transponder,
which receives it, amplifies it and beams it back to earth for reception by the remote VSATs.
The VSATs at the remote locations send information inbound (from the VSATs to the hub) via the same satellite transponder to the hub station.

This arrangement, where all network communication passes through the network's hub processor, is called a "star" configuration, with the hub station at the center of the star.
One major advantage of this configuration is that there is virtually no limit on the number
of remote VSATs that can be connected the hub. "Mesh" configurations also allow for direct communication between VSATs.

For satellites to gain a foothold in the delivery of advanced broadband services,
seamless interconnectivity with terrestrial networks is imperative.
For best results, the network should be designed to exploit the unique
virtue of satellite in geostationary orbit, namely that it can be a shared
resource available, as needed, to many users spread over a very large
proportion of the Earth's surface. This is the concept of bandwidth-on-demand.
In an ideal network, each terminal communicates with all others (full-mesh connectivity),
but utilises satellite capacity only on an as-needed basis. Such an architecture can be
implemented if the terminals operate in a Time Division Multiple Access (TDMA) mode (transmit in bursts)
and are capable of doing this at a variety of different frequencies
(FDMA and TDMA).
The DAMA System (Demand Assigned Multiple Access)
A DAMA system is typically a mesh network that allows direct connection between any two nodes in the network,
sharing the bandwidth of a satellite transponder space which can be allocated to each remote terminal as required.
DAMA supports full mesh, point-to-point or point-to-multipoint communications
 - any user can connect directly to any other user anywhere within the network
- and the most superior systems achieve this with TDMA.

The result is economical and flexible bandwidth sharing with any mix of voice, fax, video and data traffic.
The key point is that DAMA optimises the use of satellite capacity by allocating satellite resources to each
active node upon demand. By using a DAMA system, satellite resources can support a very much larger number of
users than a Single Channel Per Carrier (SCPC) system.

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Advantages of VSAT Technology

As companies compete for an increasingly savvy customer looking for value (quality and service),
information technology and communications networks are becoming tools to achieve business goals. Today's networks must support the need to improve customer service, increase per site revenues and reduce costs (all driving net income growth) - in the most cost-effective manner possible.
Further, network managers want virtual 100% availability.
They need to easily expand the network when they acquire, move or add new sites to the operations.
In addition, they require network flexibility - ease of migration from existing legacy systems as
well as addition of new network applications as their companies offer additional services to its customers
Businesses and organizations give many reasons for using VSAT networks over terrestrial alternatives.
Among them are:







    Transmission quality

    High network performance

    Fast transmissions


    Ability to handle large amounts of data

    Single vendor solution for both equipment and bandwidth

    Broadcast capability

    Ability to handle Voice, Video and Data
Who uses a VSAT system?
The installation of a VSAT system need not be an expensive option. With our expertise we can recommend a system which will cater for your requirements without selling you technology you have no need for.
A whole variety of industries use VSAT systems, such as oil and gas exploration corporations, banks, insurance companies, general stores, manufacturing organisations, ATMs and government/military departments, as well as VIPs. We would be delighted to explain the system in greater depth if you would care to contact us at VSATplus.

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