Vsat Training
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This document discusses VSAT (Very Small Aperture Terminal) technology for connecting remote sites via satellite. It provides an overview of VSAT components and configurations, as well as advantages such as availability, fast deployment, and reliability compared to other connectivity options. Different types of satellite orbits - geostationary, medium earth, and low earth - are described along with their implications for latency, coverage, and system complexity.
Vsat Training
- 1. VSAT–viable solution for remote sites connectivityBY:Syed Khurram Iqbal NaqviSystem Architect O3B NetworksFor Pakistan and Central Asia
- 2. VSAT (Very Small Aperture Terminal)A Very Small Aperture Terminal (VSAT), is a two-way satellite ground station with a dish antenna that is smaller than 3 meters. VSATs access satellites to relay data from small remote earth stations (terminals) to other terminals (in mesh configurations) or master earth station "hubs" (in star configurations).
- 3. Motivation to use VSATVSHard to reach areasReliability Time to deploy (4-6 months vs. 1-2 weeks)Cost ( If distance is more than 500 km then the VSAT solution is more cost-effective as compared to the optical fiber.)Emergency Situations
- 4. Satellite Services & ApplicationsVoice/Video/Data CommunicationsMobile Telephony
- 8. Corporate VSAT Networks
- 12. Broadcast and Cable Relay
- 13. VOIP & Multi-media over IPGPS/Navigation Position Location
- 14. Timing
- 15. Search and Rescue
- 16. Mapping
- 17. Fleet Management
- 18. Security & Database Access
- 19. Emergency Services Remote Sensing Pipeline Monitoring
- 21. Forest Fire Prevention
- 22. Urban Planning
- 23. Flood and Storm watches
- 24. Air Pollution ManagementDirect-To-Consumer Broadband IP
- 25. Digital Audio Radio
- 27. Video & Data to handheldsOccasional Use ServicesNewsgathering – First choicefor live coverage, providinghigh-bandwidth video links from remote locations to capture “breaking news”
- 28. Program Delivery – Broadcasts from television networks and relayed via satelliteUsers of Satellite CommunicationsBanking SectorData NetworksTelecommunications (Cellular) Power ProductionInfrastructureOil & Gas
- 29. AdvantagesAvailability: anywhere—no limitationsFast Deployment: Within hours!Homogeneity: Same speed and SLA regardless of locationMulticast: broadcast schemes which allows broadcast at no additional costFew Points of Failure: just two on the earth!
- 30. Advantages (contd.)Reliability:reliable satellite transmission of data between an unlimited number of geographically dispersed sites Flexibility:expansion capabilities, unrestricted and unlimited reach.Network Management:end-to-end monitoring and configuration control for all network subsystems.A low mean-time to repair - lesser elements imply lower MTTR.
- 31. DisadvantagesLatency: round trip delay of 500ms or even more!Cost of Bandwidth:high as compared to others! Environmental concerns:“fading” due to rain/snow (frequency band dependent)LOS dependency:outdoor antenna installation requires clear LOS.Interference:common to all wireless media!
- 32. Comparison between Transmission MediaOptical FiberMicrowaveCopperVSAT
- 33. Satellite-Fiber ComparisonComparing Satellite and Fiber CharacteristicsCapabilityFiber Optic Geo Satellite in a Meo Satellite in a Leo Satellite in aCableGlobal SystemGlobal SystemConstellationSystemsTransmission 10 Gbps-3.2 Single SatSingle SatSingle SatSpeedTerabits/second*1 Gbps-10 Gbps0.5 Gbps- 5 Gbps.01 Gbps-2Gbps-11-12-6-11-6-11-2 91Quality of 1010101010101010ServiceTransmission 25 to 50 ms250 ms100-150 ms25-75 mslatencySystem 93 to 99.5%99.98% (C-Ku band) 99.9% (C-Ku band)99.5% (L-C-Ku band)Availability w/o 99% (Ka band)99% (Ka band)99% (Ka band))BackupBroadcasting Low to NilHighLowLowCapabilitiesMulti-casting LowHighHighMediumCapabilitiesTrunking Very HighHighMediumLowCapabilitiesMobile ServicesNilMedium-to-HighHighHigh
- 34. VSAT Vs. Leased LineVSATFootprint across the countryHigh initial investment High reliability – Uptime of 99.5%No recurring b/w costsLeased LineOption not available in all areasLow initial investment Dependent on the capacity of the local systemRecurring Bandwidth costs
- 35. “Typical” Fixed Satellite NetworkApplications Credit Card Validation
- 36. ATM/Pay at the Pump
- 38. Store Monitoring
- 40. Training Videos
- 41. In-Store Audio
- 42. Broadband Internet Access
- 43. Distance LearningNetwork HUBApartment BuildingsInternetGas StationsCorporate Data Center/HQCorporate OfficesResidentialBranch OfficesSome large scale corporate networks have as many as 10,000 nodes
- 45. Satellite FrequenciesThere are specific frequency ranges used by commercial satellites.L-band (Mobile Satellite Services) 1.0 – 2.0 GHzS-band (MSS, DARS ) 1.55 – 3.9 GHzC-band (FSS, VSAT) 3.7 – 6.2 GHzX-Band (Military/Satellite Imagery) 8.0 – 12.0 GHzKu-band (FSS, DBS, VSAT) 11.7–14.5 GHzKa-band (FSS “broadband” and inter-satellite links) 17.7 - 21.2GHz and 27.5 – 31 GHz
- 46. VSAT TechnologyBands C-band (4-6 GHz), Ku-band (10-20 GHz) and Ka-band (20-30 GHz) that require different licensing approaches. Entities a) the Space Segment operator; b) the satellite network operator, who operates one or more Gateway Stations or Network Control Stations (HUBs) or other ground stations; c) the Satellite Service Provider; d) the subscriber who uses individual VSAT equipmentConnectivity – Point to Point (Mesh), Point to Multipoint (star, hub at centre), Multipoint to multipoint (hybrid)
- 47. Orbital OptionsA Geosynchronous satellite (GEO) completes one revolution around the world every 23 hrs and 56 minutes in order to maintain continuous positioning above the earth’s sub-satellite point on the equator. A medium earth orbit satellite (MEO) requires a constellation of 10 to 18 satellites in order to maintain constant coverage of the earth. A low earth orbit satellite (LEO) offers reduced signal loss since these satellites are 20 to 40 times closer to the earth in their orbits thus allowing for smaller user terminals/antennas.
- 48. Geostationary Orbit (GEO)Characteristics of Geostationary (GEO) Orbit SystemsUser terminals do not have to track the satellite
- 49. Only a few satellites can provide global coverage
- 50. Maximum life-time (15 years or more)
- 51. Above Van Allen Belt Radiation
- 52. Often the lowest cost system and simplest in terms of tracking and high speed switchingChallenges of Geostationary (GEO) OrbitTransmission latency or delay of 250 millisecond to complete up/down link
- 53. Satellite antennas must be of larger aperture size to concentrate power and to create narrower beams for frequency reuse
- 54. Poor look angle elevations at higher latitudesGeostationary Orbit Today
- 55. Low Earth Orbit (LEO)Characteristics of Low-Earth Orbit (LEO) Systems - Low latency or transmission delay - Higher look angle (especially in high-latitude regions) - Less path loss or beam spreading - Easier to achieve high levels of frequency re-use - Easier to operate to low-power/low-gain ground antennasChallenges of Low-Earth Orbit (LEO) Systems - Larger number of satellites (50 to 70 satellites). Thus higher launch costs to deploy, build, and operate. - Harder to deploy, track and operate. There is higher TTC&M costs even with cross links. - Shorter in-orbit lifetime due to orbital degradation
- 56. Medium Earth Orbit (MEO)Characteristics of Medium-Earth Orbit (MEO) Systems Less latency and delay than GEO (but greater than LEO)
- 57. Improved look angle to ground receivers in higher latitudes
- 58. Fewer satellites to deploy and operate and cheaper TTC&M systems than LEO (but more expensive than with GEO)
- 59. Longer in-orbit lifetime than LEO systems (but less than GEO)Challenges of Medium-Earth Orbit (MEO) SystemsMore satellites to deploy than GEO (10 to 18 vs. 3 to 4)
- 60. Ground antennas are generally more expensive and complex because of the need to track satellites. Or, one must use lower-gain, complex antennas.
- 61. Increased exposure to Van Allen Belt radiationTranspondersThe transponder is the “brain” of the satellite - provides the connection between the satellite’s receive and transmit antennas.
- 62. Satellites can have 12 to 96 transponders plus spares, depending on the size of the satellite.
- 63. A transponder bandwidth can frequently be 36 MHz, 54 MHz, or 72 MHz or it can be even wider.
- 64. A transponders function is to
- 65. Receive the signal, (Signal is one trillion times weaker then when transmitted)
- 67. Shift the frequency to a down link frequency (to avoid interference w/uplink)
- 68. Amplify for retransmission to groundFrequency EfficiencyThe vital resource in satellite communications is spectrum.
- 69. As the demand for satellite services has grown, the solution has been;
- 70. To space satellites closer together,
- 71. Allocate new spectrum in higher bands,
- 72. Make satellite transmissions more efficient so that more bits/Hz can be transmitted, and
- 73. To find ways to re-use allocated spectrum such as through geographic separation into separated cells or beams or through polarization separation
- 74. Today the satellites systems transmit more efficiently than ever before but interference is now a bigger problem - there is a basic trade off;
- 75. The higher the frequency the more spectrum that is available
- 76. But, the higher the frequency the more problems with interference from other users terrestrial, unlicensed, etc.Fixed Satellite Technology OptionsTDM/TDMATraditional data VSAT systemsLow cost remotes, expensive hubStar network topologyTransactional dataCredit card validation/POSInternet …Low user data rateFrequencyTime
- 77. Satellite Technology OptionsTDMA/DAMAStar/Mesh/Hybrid networksMultimedia, multiserviceEfficient space segment utilizationEasily expand network and site capability
- 78. Satellite Technology OptionsSCPCDAMAFrequencyTimeFrequencyTimeSample when a SCPC system is cost-effectiveSample when a DAMA system is cost-effectiveIf is a number of sites in a VSAT NetworkOne block = 64 Kbps
- 79. Type of VSAT technology
- 80. TDMA (time-division multiple access)When numerous remote sites communicate with one central hub, this design is similar to packet-switched networks.Because of competition with one another for access to the central hub, it restrict the maximum bandwidth in most cases to about 19.2 kbps.all VSATs share satellite resource on a time-slot basis.Usually used in STAR topology as a transmission technique.Offered to domestic needs.
- 81. TDMA (time-division multiple access)Copyright MaxisThe 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.
- 82. SCPC (single-carrier per channel)SCPC-based design provides a point-to-point technology, making VSAT equivalent to conventional leased lines.Normally dedicated bandwidth of up to 2 MbpsMore than 2 Mbps can be acommodated with the use of different IDU/IDU.
- 83. SCPC (single-carrier per channel)Copyright MaxisIn 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.
- 84. SCPC (single-carrier per channel)Copyright MaxisVSAT 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.
- 85. FDMA (Frequency Division Multiple Access)oldest method for channel allocationthe satellite channel bandwidth is broken into frequency bands for different earth stationsthe earth stations must be carefully power-controlled to prevent the RF power spilling into the bands for the other channels. Here, all VSATs share the satellite resource on the frequency domain only. 3 type:PAMA (Pre-Assigned Multiple Access);DAMA (Demand Assigned Multiple Access); andCDMA (Code Division Multiple Access).
- 86. PAMA (Pre-Assigned Multiple Access)The VSATs are pre-allocated a designated frequency. Equivalent of the terrestrial (land based) leased line solutions.PAMA solutions use the satellite resources constantly. Therefore, no call-up delay in the interactive data applications or high traffic volumes. PAMA connects high data traffic sites within an organization.
- 87. DAMA (Demand Assigned Multiple Access)The network uses a pool of satellite channels, which are available for use by any station in that network. On demand, a pair of available channels is assigned, so that a call can be established. Once the call is completed, the channels are returned to the pool for an assignment to another call. Since the satellite resource is used only in proportion to the active circuits and their holding times, this is ideally suited for voice traffic and data traffic in batch mode. DAMA offers point-to-point voice, fax, data requirements and supports video-conferencing. Satellite connections are established and dropped only when traffic demands them.
- 88. CDMA (Code Division Multiple Access)Under this, a central network monitoring system allocates a unique code to each of the VSATs. Enabling multiple VSATs to transmit simultaneously and share a common frequency band. The data signal is combined with a high bit rate code signal which is independent of the data. Reception at the end of the link is accomplished by mixing the incoming composite data/code signal with a locally generated and correctly synchronized replica of the code. Since this network requires that the central network management system co-ordinates code management and clock synchronization of all remote VSATs, STAR topology is the best one. Mainly used for interference rejection or for security reasons in military systems.
- 89. VSAT IMPLEMENTATIONThere are basically two ways to implement a VSAT ArchitectureSTARVSATs are linked via a HUBMESHVSATs are linked together without going through a large hub
- 90. VSAT TopologiesSTAR - the hub station controls and monitors can communicates with a large number of dispersed VSATs. Generally, the Data Terminal Equipment and 3 hub antenna is in the range of 6-11m in diameter. Since all VSATs communicate with the central hub station only, this network is more suitable for centralized data applications. MESH - a group of VSATs communicate directly with any other VSAT in the network without going through a central hub. A hub station in a mesh network performs only the monitoring and control functions. These networks are more suitable for telephony applications.HYBRID Network - In practice usually using hybrid networks, where a part of the network operates on a star topology while some sites operate on a mesh topology, thereby accruing benefits of both topologies.
- 92. VSAT STAR ARCHITECTURE In this network architecture, all of the traffic is routed via the master control station, or Hub.
- 93. If a VSAT wishes to communicate with another VSAT, they have to go via the hub, thus necessitating a “double hop” link via the satellite.
- 94. Since all of the traffic radiates at one time or another from the Hub, this architecture is referred to as a STAR network.VSAT STAR ARCHITECTURE (contd.)
- 95. STAR ARCHITECTURE (satellite’s perspective)VSATVSATSatellite HUBVSATVSATVSATTopology of a STAR VSAT network viewed from the satellite’s perspectiveNote how the VSAT communications links are routed via the satellite to the Hub in all cases.
- 96. VSAT MESH ARCHITECTURE In this network architecture, each of the VSATs has the ability to communicate directly with any of the other VSATs.
- 97. Since the traffic can go to or from any VSAT, this architecture is referred to as a MESH network.
- 98. It will still be necessary to have network control and the duties of the hub can either be handled by one of the VSATs or the master control station functions can be shared amongst the VSATs.VSAT MESH ARCHITECTURE VSAT Community
- 99. MESH ARCHITECTURE (satellite’s perspective)VSATVSATVSATVSATSatelliteVSATVSATVSATVSATVSATVSATTopology of a MESH VSAT network from the satellite’s perspectiveNote how all of the VSATs communicate directly to each other via the satellite without passing through a larger master control station (Hub).
- 100. VSAT Topologies--comparisonLower Propagation delay (250 ms)Used by PAMA/DAMA VSATsLower central hub investmentlarger VSAT antenna sizes (3.8 m typically)Higher VSAT costsSuited for high data trafficTelephony applications and point-to-point high-speed linksHigher Propagation delayUsed by TDMA VSATsHigh central hub investmentSmaller VSAT antenna sizes (1.8 m typically)Lower VSAT costsIdeally suited for interactive data applicationsLarge organizations, like banks, with centralized data processing requirements Source: www.bhartibt.com
- 101. ADVANTAGES OF STARSmall uplink EIRP of VSAT (which can be a hand-held telephone unit) compensated for by large G/T of the Hub earth stationSmall downlink G/T of user terminal compensated for by large EIRP of Hub earth stationCan be very efficient when user occupancy is low on a per-unit-time basis
- 102. DISADVANTAGES OF STARVSAT terminals cannot communicate directly with each other; they have to go through the hubVSAT-to-VSAT communications are necessarily double-hopGEO STAR networks requiring double-hops may not meet user requirements from a delay perspective
- 103. ADVANTAGES OF MESHUsers can communicate directly with each other without being routed via a Hub earth stationVSAT-to-VSAT communications are single-hop.GEO MESH networks can be made to meet user requirements from a delay perspective.
- 104. DISADVANTAGES OF MESHLow EIRP and G/T of user terminals causes relatively low transponder occupancyWith many potential user-to-user connections required, the switching requirements in the transponder will almost certainly require On-Board Processing (OBP) to be employedOBP is expensive in terms of payload mass and power requirements
- 105. Delay ConsiderationsSatellite Scenario: Typical slant path range for GEO satellite: 36,000 km
- 106. One way transmission: ESSatelliteES: 2 x Range
- 107. One way delay: 2 x (range/velocity) = 260 msFiber Optic Transcontinental Link: 4000 km has about 13 ms delayAdditionally to either case: Processing delay. Several tens to over a hundred ms.Value of Satellite SystemsValue of satellite systems grows with widely distributed networks and mobility of users
- 108. Satellite systems perform most effectively when:
- 109. interconnecting wide distributed networks,
- 110. providing broadcasting services over very wide areas such as a country, region, or entire hemisphere
- 111. providing connectivity for the “last mile” in cases where fiber networks are simply not available for interactive services.
- 112. providing mobile wideband and narrow band communications
- 113. satellites are best and most reliable form of communications in the case of natural disasters or terrorist attacks - fiber networks or even terrestrial wireless can be disrupted bytsunamis, earthquakes, etc..World Satellite Industry Revenues$91.0$86.1$78.6$73.7$60.4$55.0$49.1$38.0
- 114. Global Supply vs. DemandGEO Communications Satellites and Launches
- 115. VSAT: A Consistent Performer160,000140,000120,000100,00080,00060,00040,00020,000-8586878889909192939495969798990001
- 116. Opportunities in VSAT technologyVoice over IP (VoIP) via satelliteFrame Relay via satelliteATM via satelliteVideo-on-demand via satelliteMultimedia applicationInternet/e-mail connectionTelemedicineDistance learning
- 117. Summary(of previous discussion)Satellite technology is the fastest way to get a reliable connection from A to B in an emergency situation.Both a SCPC and a DAMA solution can be used in an emergency situation as a VSAT connection. Both technologies can be used as a FlyAway (Quick deploy) system. Both systems can run the same services.
- 119. Solution DetailsFrequency BandOutdoor EquipmentIndoor EquipmentInterfacing
- 120. Ground AntennasThe size of the antenna depends on the satellite frequency band used, the data rate, and whether the service is bidirectional or receive onlyHigher data rates require larger antennas and/or higher powerHigher transmit capability (EIRP) of the satellite allows the antenna size to be reduced The use of spot beams instead of global beams improves VSAT link performanceReceive-only antennas can be substantially smaller
- 121. Steps in Installation of a VSAT site Technical Site SurveyCivil Work Antenna MountingPointing of AntennaConfiguration of ODU
- 122. Steps in Installation of a VSAT siteConfiguration of Indoor UnitTesting on RF levelInterfacingBER testingIntegration (with the BTS/BSC)
- 123. Quality Assurance TestsBER testingSpectrum AnalysisCarrier to Noise Ratio measurement
- 124. Common Faults/ProblemsFading (due to rain etc.)LOS obstructionsODU/IDU malfunctionsDe-pointing of AntennaInterference
- 125. O & M ProceduresCarrier MonitoringSpectrum AnalysisFault Diagnosis/LocalizationRF Power adjustmentetc. etc.
- 126. Thank You!