VSAT is an abbreviation for a Very Small Aperture Terminal. It is basically a two-way satellite ground station with a less than 3 meters tall (most of them are about 0.75 m to 1.2 m tall) dish antenna stationed. The transmission rates of VSATs are usually from very low and up to 4 Mbit/s. These VSATs’ primary job is accessing the satellites in the geosynchronous orbit and relaying data from terminals in earth to other terminals and hubs.
WHAT IS SATELLITE:-
A satellite is basically any object that revolves around a planet in a circular or elliptical path. The moon is Earth's original, natural satellite, and there are many manmade (artificial) satellites, usually closer to Earth.
WHAT IS SATELLITE COMMUNICATION?
The term Satellite communication is very frequently used, but what is satellite communication? It is simply the communication of the satellite in space with large number of earth stations on the ground. Users are the ones who generate baseband signals, which is processed at the earth station and then transmitted to the satellite through dish antennas. Now the user is connected to the earth station via some telephone switch or some dedicated link.
Constituent parts of a VSAT configuration:-
Block upconverter (BUC)
Low-noise block converter (LNB)
Orthomode transducer (OMT)
Interfacility Link Cable (IFL)
Indoor unit (IDU)
An antenna (or aerial) is a transducer that transmits or receives electromagnetic waves. In other words, antennas convert electromagnetic radiation into an electrical signal and vice versa
BLOCK UP CONVERTER(BUC):-
A block upconverter (BUC) is used in the transmission (uplink) of satellite signals. It converts a band (or "block") of frequencies from a lower frequency to a higher frequency. Modern BUCs convert from the L band to Ku band, C band and Ka band. Older BUCs convert from a 70 MHz intermediate frequency (IF) to Ku band or C band.
Low-noise block converter (LNB):-
A low noise block-downconverter (or LNB) is the receiving device of a parabolic satellite dish antenna of the type commonly used for satellite TVreception. The device is sometimes called an LNA (for low noise amplifier), LNC (for low noise converter) or even LND (for low noise downconverter) but as block-downconversion is the principle function of the device, LNB is the preferred term, although this acronym is often incorrectly expanded to the incomplete descriptions, low noise block or low noise block converter.[
Orthomode transducer (OMT) :-
An orthomode transducer is a microwave duct component of the class of microwave circulators. It is commonly referred to as an OMT, and commonly referred as a polarisation duplexer. Such device may be part of a VSAT antenna feed Orthomode transducers serve either to combine or to separate two microwave signal paths. One of the paths forms the uplink, which is transmitted over the same waveguide as the received signal path, or downlink path.
Interfacility Link Cable (IFL) :-
An Inter-Facility Link (IFL) is the set of coaxial cables that connect the indoor equipment to the outdoor equipment of a satellite earth station. In a VSAT terminal, the IFL is usually one or two co-axial cables carrying IF signals, control signals, and DC powe
Indoor unit (IDU) :-
The Indoor Unit (IDU) is the component of the VSAT terminal that is located indoors. It is usually the satellite router. The IDU is connected to the Outdoor Unit (ODU) via Inter-Facility Link (IFL) cables
HOW COMMUNICATION IS DONE USING VSAT:-
The earth station communicating with vsat can not transmit signal to to the satellite
Two way vsat:-
Station dealing with vsat can transmit signal to satellite as well as receive also
Mesh Network is a network where all the VSATS are connected to each other and is a complete network. In a Mesh Network every VSAT is connected to other VSAT on the network through hops. Some are connected through single vsat and some may be connected with more than one vsat.
Low cost broadband access
Return channel configuration based on business requirements
Very small contention rates where required
IP encryption for secure networking
Reliability and quality of service guaranteed by SLA
One stop solution for network design, implementation and support
Centrally managed from Datasat's UK Teleport
Monthly flat rate billing for subscribed bandwidth
VSAT’s Strengths :-
VSAT technology has many advantages, which is the reason why it is used so widely today.
One is availability.
The service can basically be deployed anywhere around the world.
the VSAT is diverse in that it offers a completely independent wireless link from the local infrastructure,
which is a good backup for potential disasters.
Its deployability is also quite amazing as the VSAT services can be setup in a matter of minutes.
The strength and the speed of the VSAT connection being homogenous anywhere within the boundaries is also a big plus.
Not to forget, the connection is quite secure as they ar private layer-2 networks over the air.
The pricing is also affordable, as the networks themselves do not have to pay a lot, as the broadcast download scheme (eg. DVB-S) allows them to serve the same content to thousands of locations at once without any additional costs.
Last but not least, most of the VSAT systems today use onboard acceleration of protocols (eg. TCP, HTTP), which allows them to delivery high quality connections regardless of the latency
As with everything, VSAT also has its downsides.
Firstly, because the VSAT technology utilizes the satellites in geosynchronous orbit,
it takes a minimum latency of about 500 milliseconds every trip around.
Therefore, it is not the ideal technology to use with protocols that require a constant back and forth transmission, such as online games.
surprisingly, the environment can play a role in slowing down the VSATs.
Although not as bad as one way TV systems like DirecTV and DISH Network, the VSAT still can have a dim signal, as it still relies on the antenna size,
the transmitter’s power, and the frequency band.
Last but not least, although not that big of a concern,
installation can be a problem as VSAT services require an outdoor antenna that has a clear view of the sky.
An awkward roof, such as with skyscraper designs, can become problematic
Advances in technology have dramatically improved the price/performance equation of FSS (Fixed Service Satellite) over the past five years.
New VSAT systems are coming online using Ka bandtechnology that promise higher bandwidth rates for lower costs.
FSS satellite systems currently in orbit have a huge capacity with a relatively low price structure. FSS satellite systems provide various applications for subscribers,
including: telephony, fax, television, high speed data communication services, Internet access, Satellite News Gathering (SNG), Digital Audio Broadcasting (DAB) and others.
These systems are applicable for providing various high-quality services because they create efficient communication systems, both for residential and business users.