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1VSAT[Very Small Aperture Antenna]

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2

11BEC1015 -KOTESWARA RAO

11BEC1034 -T.KRISHNA CHAITANYA

11BEC1035 -VIDYANATH.M

11BEC1074 -K.HARSHAVARDHAN

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3 What is VSAT?

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

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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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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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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 VSAT SYSTEMS

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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Fig. 2.5 in: INTELSAT VSAT Handbook, September 1998. Available from ApplicationSupport and Training, INTELSAT, 3400 International Drive, NW, Washington, DC

20008-3098, USA

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Implementations of VSAT

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11 Implementation

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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VSAT IMPLEMENTATION

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 VSAT IMPLEMENTATION

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

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

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14 VSAT Network Topologies

Star network:

The VSAT terminals communicate each other through Hub.

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15 VSAT STAR ARCHITECTURE

Master Control Station(The Hub)

VSATCommunity

All communications to andfrom each VSAT is via theMaster Control Station orHub

Picture copyrights on introductory slides. Reproduction with permission only.

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16 VSAT Earth Station

Outdoor Unit (ODU) Inter-facility link (IFL) Indoor Unit (IDU)

Source: www.bhartibt.com

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17 VSAT Earth Station • 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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Typical VSAT Outdoor Unit/Antenna

LNB

Reflector

LNB-F (Optional)

(Front) (Rear)

Feed-Assembly

SSPA (HPC)

LNB-F (Optional)

LNB

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19VSAT Earth Station - Block Diagram

AntennaFeed

LNC

HPC

DEM

MOD

ToData Terminal Equipment

IFL

Outdoor Unit (ODU)

Indoor Unit (IDU)

RFT

Base Band

Processor

(BBP)

RFT

IFL

IDU

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20 VSAT for Internet

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21 VSAT Network

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22 From TV station to home

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23 What are the applications of VSAT? 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

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24 Who should subscribe to VSAT? 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 Advantages of VSAT

Access in Remote Locations Internet Access Rapid deployment VPN Qos Mobile Access Bandwidth Allocation Scalable

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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 Limitations of VSAT Technology

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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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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Thank you