Vsat E-commerce

Satellite CommunicationSatellite Communication

VERY SMALL APERTURE VERY SMALL APERTURE TERMINAL (VSAT)TERMINAL (VSAT)

E-CommerceE-CommerceElectronic Electronic

Communication Communication Contd….Contd….

Introduction Introduction • Satellite Communicationis a technology of data transmission whether one-way data broadcasting or two-way interactive using frequency as a medium.

Consist of :• Space Segment or Satellite ( eg. Measat, Intelsat, Inmarsat )• Ground Segment or earth station which includes Antenna,

Outdoor Unit, Inter Facility Link, Indoor Unit and Customer Premises Equipment.

• VSAT is a satellite-based communications service that offers flexible and reliable communications solutions including Enterprise Wide Networking with high reliability and a wide reach that extend even to remote sites.

Why VSAT? Why VSAT? VSAT networks provides:VSAT networks provides:

• Reliability in transmission of data (data, voice, video)Reliability in transmission of data (data, voice, video)

• Allocation of resources to different users (bandwidth, amplification Allocation of resources to different users (bandwidth, amplification

power) power)

– Provide point-to-multipoint (broadcast), Provide point-to-multipoint (broadcast),

– multipoint-to-point (data collection), multipoint-to-point (data collection),

– point-to-point communications and point-to-point communications and

– broadband multimedia services. broadband multimedia services.

• Serviced in land area which are difficult to install (remote Serviced in land area which are difficult to install (remote

locations ,water areas).locations ,water areas).

• An ability to have direct access to users and user premises.An ability to have direct access to users and user premises.

Type of satellite serviceType of satellite service

• International Telephony – using Public Switched International Telephony – using Public Switched Telephone Network (PSTN)Telephone Network (PSTN)– Intermediate Data Rate (IDR)Intermediate Data Rate (IDR)– Time Division Multiple Access (TDMA)Time Division Multiple Access (TDMA)

• BroadcastingBroadcasting– TV UplinkTV Uplink– Television Receive Only (TVRO)Television Receive Only (TVRO)– Digital Satellite News Gathering (DSNG)Digital Satellite News Gathering (DSNG)

• VSATVSAT– Personal Earth Station (PES-TDMA)Personal Earth Station (PES-TDMA)– Telephony Earth Station (TES-TDMA)Telephony Earth Station (TES-TDMA)– Domestic IDR/Single Channel Per Carrier (SCPC)Domestic IDR/Single Channel Per Carrier (SCPC)– FDMA (Frequency Division Multiple Access)FDMA (Frequency Division Multiple Access)

Satellite Communication ConceptSatellite Communication Concept

Note :Note :HPA – High Power Amplifier (Earth station equipment that amplifies the HPA – High Power Amplifier (Earth station equipment that amplifies the transmit RF signal. )transmit RF signal. )CPE – customer premises equipment ( eg. Telephone, PABX, Ethernet CPE – customer premises equipment ( eg. Telephone, PABX, Ethernet hub, host server, etc.)hub, host server, etc.)

Transmitting Earth

Station

Receiving Earth

Station

Uplink 6 GHz

Downlink 4 GHzHPA

Up Converter

Satellite Modem

CPE PSTN

LNA

Down Converter

Satellite Modem

CPE PSTN

C Band – 6/4GHzKu Band -14/12GHzKa Band – 30/20GHz

Typical VSAT systemTypical VSAT system

• antenna varies - antenna size antenna varies - antenna size describe the ability of the antenna to describe the ability of the antenna to amplify the signal strengthamplify the signal strength• feed-horn directs transmitted power feed-horn directs transmitted power to antenna dish or collects the to antenna dish or collects the received power from it. received power from it.

• Radio Frequency Terminal (RFT) is mounted on Radio Frequency Terminal (RFT) is mounted on the antenna frame and interconnected to the the antenna frame and interconnected to the feed-horn + Low Noise Amplifiers (LNA) + down-feed-horn + Low Noise Amplifiers (LNA) + down-converters. converters. • LNAs – minimize signal noise. Noise temperature LNAs – minimize signal noise. Noise temperature is parameter used to describe the performance of is parameter used to describe the performance of an LNA.an LNA.

• Up- converters and High Powered Up- converters and High Powered Amplifiers (HPA) used for converting and Amplifiers (HPA) used for converting and amplifying the signal before transmitting to amplifying the signal before transmitting to the feed-horn. the feed-horn. • Extended C band, down converter Extended C band, down converter receives the signal at 4.5 to 4.8GHz and receives the signal at 4.5 to 4.8GHz and the up converter converts it to 6.725 to the up converter converts it to 6.725 to 7.025GHz. 7.025GHz.

VSAT ServicesVSAT Services• Interactive real time application:Interactive real time application:

– Point of Sale/retail/Banking (eg. ATM)Point of Sale/retail/Banking (eg. ATM)– Corporate dataCorporate data

• TelephonyTelephony– Rural : individual subscribersRural : individual subscribers– Corporate TelephonyCorporate Telephony

• Intranet, Internet and IP infrastructureIntranet, Internet and IP infrastructure– Multimedia delivery (eg. video streaming)Multimedia delivery (eg. video streaming)– Interactive distance learning/ trainingInteractive distance learning/ training

• Direct-to-homeDirect-to-home– Broadband Internet access for consumers and Broadband Internet access for consumers and

businessesbusinesses

VSAT TopologyVSAT Topology• STARSTAR - the hub station controls and monitors can - the hub station controls and monitors can

communicates with a large number of dispersed VSATs. communicates with a large number of dispersed VSATs. Generally, the Data Terminal Equipment and 3 hub Generally, the Data Terminal Equipment and 3 hub antenna is in the range of 6-11m in diameter. Since all antenna is in the range of 6-11m in diameter. Since all VSATs communicate with the central hub station only, VSATs communicate with the central hub station only, this network is more suitable for centralized data this network is more suitable for centralized data applications. applications.

• MESHMESH - a group of VSATs communicate directly with - a group of VSATs communicate directly with any other VSAT in the network without going through a any other VSAT in the network without going through a central hub. A hub station in a mesh network performs central hub. A hub station in a mesh network performs only the monitoring and control functions. These only the monitoring and control functions. These networks are more suitable for telephony applications.networks are more suitable for telephony applications.

• HYBRID NetworkHYBRID Network - In practice usually using hybrid - In practice usually using hybrid

networks, where a part of the network operates on a star networks, where a part of the network operates on a star topology while some sites operate on a mesh topology, topology while some sites operate on a mesh topology, thereby accruing benefits of both topologies. thereby accruing benefits of both topologies.

What is VSAT Accessing Scheme?What is VSAT Accessing Scheme?

The objective of VSAT networks:The objective of VSAT networks: - - is to maximize the use of common satellite is to maximize the use of common satellite

and other resources amongst all VSAT and other resources amongst all VSAT sites. sites.

The method:The method:- by optimizing the use of satellite capacity, by optimizing the use of satellite capacity,

and spectrum utilization in a flexible and and spectrum utilization in a flexible and cost-effective manner ( referred as cost-effective manner ( referred as satellite access schemes.) satellite access schemes.)

- or we can call as VSAT technology.or we can call as VSAT technology.

Type of VSAT technologyType of VSAT technology

TDMATime-division

Multiple Access

TDMATime-division

Multiple Access

FDMAFrequency Division Frequency Division

Multiple AccessMultiple Access

FDMAFrequency Division Frequency Division


SCDCSingle-carrier Single-carrier per Channelper Channel

SCDCSingle-carrier Single-carrier per Channelper Channel

VSAT TECHNOLOGY

VSAT TECHNOLOGY

DAMADAMA Demand Assigned Demand Assigned


CDMACDMA Code Division Code Division Multiple AccessMultiple Access

PAMAPAMA Pre-Assigned Pre-Assigned


FDMA

TDMA (time-division multiple access)TDMA (time-division multiple access)

• When numerous remote sites communicate with When numerous remote sites communicate with one central hub, this design is similar to packet-one central hub, this design is similar to packet-switched networks.switched networks.

• Because of competition with one another for Because of competition with one another for access to the central hub, it restrict the access to the central hub, it restrict the maximum bandwidth to most cases is about 19.2 maximum bandwidth to most cases is about 19.2 kbps.kbps.

• all VSATs share satellite resource on a time-slot all VSATs share satellite resource on a time-slot basis.basis.

• Usually used in STAR topology as a Usually used in STAR topology as a transmission technique.transmission technique.

• Offered to domestic needs. Offered to domestic needs.


The VSAT Hub communicates with all dispersed VSATs (typically a 1.8-meter diameter parabolic-shaped dish) on an outgoing channel of up to 512kbps based on the TDM scheme. The incoming or return channel from the dispersed VSATs uses the TDMA channel technology that enables a large number of the respective VSATs to share this single return channel. The incoming routes typically operate at 128kbps, and can go up to a maximum bandwidth of 256kbps.

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Petrol stations, information providers, retail chains, financial institutions and any large corporation that requires transfers of low to medium rate data applications between its head office and, local and outstation branch offices. Example of Point of Sales (POS transactions), Credit Card Verification, Reservations Systems Financial and Banking applications (teller, loans, ATM) etc.

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SCDC (single-carrier per channel)SCDC (single-carrier per channel)

• SCPC-based design provides a point-to-SCPC-based design provides a point-to-point technology, making VSAT equivalent point technology, making VSAT equivalent to conventional leased lines.to conventional leased lines.

• dedicated bandwidth of up to 2 Mbpsdedicated bandwidth of up to 2 Mbps

• Usually use in an international VSAT Usually use in an international VSAT services in Asia-Pacific. services in Asia-Pacific.


In the Hub-to-Remote configuration, one end of the VSAT link (normally the customer's HQ) is connected to the 11-meter VSAT Hub (Earth Station) via a terrestrial leased line. A VSAT antenna at the remote end or the distant end (normally the branch office) of the VSAT link is then interconnected to the VSAT hub via the satellite.

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VSAT links with a Remote-to-Remote configuration bypass the VSAT Hub and has a stand-alone VSAT antenna at both ends of the link. Typical VSAT antenna size ranges from 1.8m to 2.4m.

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FDMA (Frequency Division Multiple Access)FDMA (Frequency Division Multiple Access)

• oldest method for channel allocationoldest method for channel allocation• the satellite channel bandwidth is broken into the satellite channel bandwidth is broken into

frequency bands for different earth stationsfrequency bands for different earth stations• the earth stations must be carefully power-the earth stations must be carefully power-

controlled to prevent the microwave power controlled to prevent the microwave power spilling into the bands for the other channels. spilling into the bands for the other channels. Here, all VSATs share the satellite resource on Here, all VSATs share the satellite resource on the frequency domain only. the frequency domain only.

3 type:3 type:• PAMA (Pre-Assigned Multiple Access);PAMA (Pre-Assigned Multiple Access);• DAMA (Demand Assigned Multiple Access); andDAMA (Demand Assigned Multiple Access); and• CDMA (Code Division Multiple Access)CDMA (Code Division Multiple Access). .

PAMA (Pre-Assigned Multiple Access);PAMA (Pre-Assigned Multiple Access);

• the VSATs are pre-allocated a designated the VSATs are pre-allocated a designated frequency. Equivalent of the terrestrial frequency. Equivalent of the terrestrial (land based) leased line solutions.(land based) leased line solutions.

• PAMA solutions use the satellite resources PAMA solutions use the satellite resources constantly. Therefore, no call-up delay in constantly. Therefore, no call-up delay in the interactive data applications or high the interactive data applications or high traffic volumes. traffic volumes.

• PAMA connects high data traffic sites PAMA connects high data traffic sites within an organization. within an organization.

DAMA (Demand Assigned Multiple Access);DAMA (Demand Assigned Multiple Access);

• The network uses a pool of satellite channels, which are The network uses a pool of satellite channels, which are available for use by any station in that network. available for use by any station in that network.

• On demand, a pair of available channels is assigned, so On demand, a pair of available channels is assigned, so that a call can be established. Once the call is that a call can be established. Once the call is completed, the channels are returned to the pool for an completed, the channels are returned to the pool for an assignment to another call. assignment to another call.

• Since the satellite resource is used only in pro-portion to Since the satellite resource is used only in pro-portion to the active circuits and their holding times, this is ideally the active circuits and their holding times, this is ideally suited for voice traffic and data traffic in batch mode. suited for voice traffic and data traffic in batch mode.

• DAMA offers point-to-point voice, fax, data requirements DAMA offers point-to-point voice, fax, data requirements and supports video-conferencing. Satellite connections and supports video-conferencing. Satellite connections are established and dropped only when traffic demands are established and dropped only when traffic demands them.them.

CDMA (Code Division Multiple Access)CDMA (Code Division Multiple Access)• Under this, a central network monitoring system Under this, a central network monitoring system

allocates a unique code to each of the VSATs. Enabling allocates a unique code to each of the VSATs. Enabling multiple VSATs to transmit simultaneously and share a multiple VSATs to transmit simultaneously and share a common frequency band. common frequency band.

• The data signal is combined with a high bit rate code The data signal is combined with a high bit rate code signal which is independent of the data. signal which is independent of the data.

• Reception at the end of the link is accomplished by Reception at the end of the link is accomplished by mixing the incoming composite data/code signal with a mixing the incoming composite data/code signal with a locally generated and correctly synchronized replica of locally generated and correctly synchronized replica of the code. the code.

• Since this network requires that the central network Since this network requires that the central network management system co-ordinates code management management system co-ordinates code management and clock synchronization of all remote VSATs, STAR and clock synchronization of all remote VSATs, STAR topology is the best one. topology is the best one.

• Mainly used for interference rejection or for security Mainly used for interference rejection or for security reasons in military systems.reasons in military systems.

VSAT Characteristic and VSAT Characteristic and AdvantageAdvantage

• ReliabilityReliability: reliable satellite transmission of data, voice and video : reliable satellite transmission of data, voice and video between an unlimited number of geographically dispersed sites or between an unlimited number of geographically dispersed sites or from these sites to headquarters from these sites to headquarters

• FlexibilityFlexibility: The VSAT networks offer enormous expansion : The VSAT networks offer enormous expansion capabilities; On the other hand, VSATs offer unrestricted and capabilities; On the other hand, VSATs offer unrestricted and unlimited reach. Additional VSATs can be rapidly installed to unlimited reach. Additional VSATs can be rapidly installed to support the network expansion to any site, no matter however support the network expansion to any site, no matter however remote.remote.

• Network ManagementNetwork Management: Network monitoring and control of the entire : Network monitoring and control of the entire VSAT network is much simpler than a network of leased lines, easily VSAT network is much simpler than a network of leased lines, easily integrates end-to-end monitoring and configuration control for all integrates end-to-end monitoring and configuration control for all network subsystems.network subsystems.

• A low mean-time to repairA low mean-time to repair - few hours, compare to leased lines - few hours, compare to leased lines which extends up to a few days. Essentially, lesser elements imply which extends up to a few days. Essentially, lesser elements imply lower MTTR. Uptime of up to 99.5 percent is achievable on a VSAT lower MTTR. Uptime of up to 99.5 percent is achievable on a VSAT network. This is significantly higher than the typical leased line network. This is significantly higher than the typical leased line uptime of approximately 80-85%.uptime of approximately 80-85%.

• CostCost: VSAT network offers significant savings over 2-3 : VSAT network offers significant savings over 2-3 years timeframe. The service charges depend on the years timeframe. The service charges depend on the bandwidth which is allocated to the network in line with bandwidth which is allocated to the network in line with customer requirements. customer requirements.

• Link BudgetsLink Budgets: RF equipment would cater to the : RF equipment would cater to the requirements of the network topology and satellite requirements of the network topology and satellite modems in use. The link Budget estimates the ground modems in use. The link Budget estimates the ground station and satellite EIRP (station and satellite EIRP (Effective Isotropic Radiated Effective Isotropic Radiated Power) Power) required. Calculations of signal levels through required. Calculations of signal levels through the system to ensure the quality of service should the system to ensure the quality of service should normally be done, prior to the establishment of a satellite normally be done, prior to the establishment of a satellite link. link.

VSAT Characteristic and VSAT Characteristic and AdvantageAdvantage

Opportunities in VSAT technologyOpportunities in VSAT technology

• Voice over IP (VoIP) via satelliteVoice over IP (VoIP) via satellite

• Frame Relay via satelliteFrame Relay via satellite

• ATM via satelliteATM via satellite

• Video-on-demand via satelliteVideo-on-demand via satellite

• Multimedia applicationMultimedia application– Internet/e-mail connectionInternet/e-mail connection– TelemedicineTelemedicine– Distance learningDistance learning

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