VSAT is a satellite communication system that uses small satellite dishes to transmit and receive signals to and from orbiting satellites. It provides broadcast and interactive applications like data, voice, and video to areas not served by terrestrial lines. VSAT systems use small dishes that are less than 1.2 meters wide, which are cheaper and easier to install than the large 30-meter dishes originally used in satellite communication systems. VSAT networks operate in a star configuration with terminals connecting through a central hub to provide flexible, scalable communication services.

1. VSAT
[Very Small Aperture Antenna]
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 11BEC1034 -T.KRISHNA CHAITANYA
 11BEC1035 -VIDYANATH.M
 11BEC1074 -K.HARSHAVARDHAN
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3. VSAT stands for Very Small Aperture Terminal. It is a
small satellite dish that is capable of both receiving and
sending satellite signals. VSAT systems can be designed
to serve both broadcast and interactive applications
whether data, voice or video, which are now being
served by terrestrial lines.
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4. Why VSAT?
• Early Earth Stations in commercial systems were very
large and expensive (30 m).
• Need to make system more affordable to end user:
• Increased transmit power from satellite.
• Higher frequencies
• Result: Smaller ES antenna size required 5/16/2014
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5. The dish is small, easily transportable and
installation lead-time is much shorter if compared
to terrestrial links. In addition, VSAT network
allows rapid, low-cost network re-configuration
and expansion to meet new or unexpected business
requirements.
VSAT - 75 cm to 1.2 m.
 Data rates - 4 kbit/s up to 4 Mbit/s
sometimes up to a max downlink of up to 16
Mbit/s with some upgraded modules and
enhancements.
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6. Cost effective transmission and network operations
are made possible by use of the C-band satellite
frequency and frequency times division multiple
access (FTDMA), Frequency division multiple
access (FDMA) or Time division multiple access
(TDMA) transmission techniques.
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7. VSAT offers a wide of protocols and
features, providing extraordinary flexibility and
virtually unlimited expansion capabilities. In
addition, VSAT network is typically engineered to
achieve a minimum of 99.7% end-to-end
availability for all locations
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8. Underlying objective of VSAT Systems:
bring the service directly to the end-user
Major reasons for doing this
Reduce hierarchical distribution network (make
more efficient and faster)
Reduce distribution costs
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9. Fig. 2.5 in: INTELSAT VSAT Handbook, September 1998. Available from Application
Support and Training, INTELSAT, 3400 International Drive, NW, Washington, DC
20008-3098, USA
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11. There are several ways VSAT services might be
implemented
One-Way (e.g. TV Broadcasting satellites)
Split-Two-Way (Split IP) Implementation (return link
from user is not via the satellite; e.g. DirecTV)
Two-Way Implementation (up- and down-link)
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12. There are basically two ways to
implement a VSAT Architecture
STAR
VSATs are linked via a HUB
MESH
VSATs are linked together without going
through a large hub
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13. Higher Propagation delay
Used by TDMA VSATs
High central hub investment
Smaller VSAT antenna sizes (1.8 m typically)
Lower VSAT costs
Ideally suited for interactive
data applications
Large organizations, like banks, with
centralized data processing requirements
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Lower Propagation delay (250 ms)
Used by PAMA/DAMA VSATs
Lower central hub investment
larger VSAT antenna sizes (3.8 m typically)
Higher VSAT costs
Suited for high data traffic
Telephony applications and point-to-point
high-speed links

14.  Star network:
The VSAT terminals communicate each other through Hub.
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Master Control Station
(The Hub)
VSAT
Community
All communications to and
from each VSAT is via the
Master Control Station or
Hub
Picture copyrights on introductory slides. Reproduction with permission only.

16. Outdoor Unit (ODU)
Inter-facility link (IFL)
Indoor Unit (IDU)
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Source: www.bhartibt.com

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• The VSAT Outdoor Unit (ODU) is located where it will have a clear line
of sight to the satellite and is free from casual blockage by people and/or
equipment moving in front of it. It includes the Radio Frequency Trasceiver
(RFT).
• The Inter Facility Link (IFL) carries the electronic signal between the
ODU and the Indoor Unit (IDU) as well as power cables for the ODU and
control signals from the IDU.
• The IDU is normally housed in a desktop computer at the User’s
workstation and consists of the baseband processor units and interface
equipment (e.g. computer screen and keyboard). The IDU will also house
the modem and multiplexer/demultilexer (mux/demux) units if these are not
already housed in the ODU.

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LNB
Reflector
LNB-F (Optional)
(Front) (Rear)
Feed-Assembly
SSPA (HPC)
LNB-F (Optional)
LNB

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Antenn
aFee
d
LNC
HPC
DEM
MO
D
To
Data
Terminal
Equipmen
t
IFL
Outdoor Unit
(ODU)
Indoor Unit (IDU)
RFT
Base
Band
Processor
(BBP)
RFT
IFL
IDU

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23. VSAT is an ideal satellite network that provides
communications support for a wide range of applications: -
Point-of-sales transaction
- Order-Entry Billing
- Inventory Control
- Financial Management
- Data processing
- Reservation System
- Telemetry & Data Collection
- News Wire Services
- Private-Line Voice
- Virtual Private Networks
- Distance Education
- High Speed Internet Access 5/16/2014
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24. VSAT presents new alternatives to the problems of
conventional fixed terrestrial telecommunication beyond
PSTN areas. VSAT can also help to design tailored
communication business to the following sectors: - Finance
and banking
- Government Agencies
- Manufacturing
- Mining and explorations
- News agency
- Shipping and freight handling·
- Travel and tourism
- Agricultural companies
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25. Access in Remote Locations
Internet Access
Rapid deployment
VPN
Qos
Mobile Access
Bandwidth Allocation
Scalable 5/16/2014
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26. Cost
Standards based
Reliable
Back-up to Terrestrial Networks
Inter-operation with Terrestrial Networks
Single Hop
Bandwidth on Demand
Cost per connection is independent of the location/
distance
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27. Like any other technology, VSAT has its limitations too.
Some of them include the extremely high initial
cost needed for building and launching satellites in the
Geo-Synchronous orbit, higher initial cost and recurring
monthly costs for terminal equipments needed for
providing Internet over broadband when compared to
terrestrial DSL networks, Bit Error Rate is common for
satellite based technologies, Rain Attenuation might
affect the performance of VSAT communications under
rainy conditions,
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28. latencies (>200 ms) are still higher than their terrestrial equivalent
technologies (<100 ms),careful direction of subscriber side
terminals and dish antennas are critical for proper working,trained
man power is required for installation and
maintenance, other competitive technologies(Internet Leased
Lines, 3G/HSDPA/4G Cellular technologies etc) offer much
higher bandwidth at a lower cost than what is possible by VSAT
based networks, the antennas need to be fixed outside the offices
or homes hence making them susceptible to damage or theft, the
cost of VSAT modules for Network Routers/ Video Conferencing
systems are quite high, etc
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29. Thank you
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