1. VSAT–viable solution for remote sites connectivity BY: Syed Khurram Iqbal Naqvi System Architect O3B Networks For 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 VSAT VS Hard to reach areas Reliability 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

5. Rural Telephony

6. News Gathering/Distribution

7. Internet Trunking

8. Corporate VSAT Networks

9. Distance-Learning

10. Videoconferencing

11. Business Television

12. Broadcast and Cable Relay

14. Timing

15. Search and Rescue

16. Mapping

17. Fleet Management

18. Security & Database Access

20. Infrastructure Planning

21. Forest Fire Prevention

22. Urban Planning

23. Flood and Storm watches

25. Digital Audio Radio

26. Interactive Entertainment

29. Advantages Availability: anywhere—no limitations Fast Deployment: Within hours! Homogeneity: Same speed and SLA regardless of location Multicast: broadcast schemes which allows broadcast at no additional cost Few 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. Disadvantages Latency: 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 Media Optical Fiber Microwave Copper VSAT

33. Satellite-Fiber Comparison Comparing Satellite and Fiber Characteristics Capability Fiber Optic Geo Satellite in a Meo Satellite in a Leo Satellite in a Cable Global System Global System Constellation Systems Transmission 10 Gbps - 3.2 Single Sat Single Sat Single Sat Speed Terabits/second* 1 Gbps - 10 Gb ps 0.5 Gbps - 5 Gbps .01 Gbps - 2Gbps - 11 - 12 - 6 - 11 - 6 - 11 - 2 91 Quality of 10 10 10 10 10 10 10 10 Service Transmission 25 to 50 ms 250 ms 100 - 150 ms 25 - 75 ms latency System 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 ban d) 99% (Ka band) 99% (Ka band)) Backup Broadcasting Low to Nil High Low Low Capabilities Multi - casting Low High High Medium Capabilities Trunking Very High High Medium Low Capabilities Mobile Services Nil Medium - to - High High High

34. VSAT Vs. Leased Line VSAT Footprint across the country High initial investment High reliability – Uptime of 99.5% No recurring b/w costs Leased Line Option not available in all areas Low initial investment Dependent on the capacity of the local system Recurring Bandwidth costs

36. ATM/Pay at the Pump

37. Inventory Control

38. Store Monitoring

39. Electronic Pricing

40. Training Videos

41. In-Store Audio

42. Broadband Internet Access

43. Distance LearningNetwork HUB Apartment Buildings Internet Gas Stations Corporate Data Center/HQ Corporate Offices Residential Branch Offices Some large scale corporate networks have as many as 10,000 nodes

44. Satellite Network ConfigurationsVSAT

45. Satellite Frequencies There are specific frequency ranges used by commercial satellites. L-band (Mobile Satellite Services) 1.0 – 2.0 GHz S-band (MSS, DARS ) 1.55 – 3.9 GHz C-band (FSS, VSAT) 3.7 – 6.2 GHz X-Band (Military/Satellite Imagery) 8.0 – 12.0 GHz Ku-band (FSS, DBS, VSAT) 11.7–14.5 GHz Ka-band (FSS “broadband” and inter-satellite links) 17.7 - 21.2GHz and 27.5 – 31 GHz

46. VSAT Technology Bands 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 equipment Connectivity – Point to Point (Mesh), Point to Multipoint (star, hub at centre), Multipoint to multipoint (hybrid)

47. Orbital Options A 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.

49. Only a few satellites can provide global coverage

50. Maximum life-time (15 years or more)

51. Above Van Allen Belt Radiation

53. Satellite antennas must be of larger aperture size to concentrate power and to create narrower beams for frequency reuse

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 antennas Challenges 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

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)

60. Ground antennas are generally more expensive and complex because of the need to track satellites. Or, one must use lower-gain, complex 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)

66. Filter out noise,

67. Shift the frequency to a down link frequency (to avoid interference w/uplink)

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

77. Satellite Technology Options TDMA/DAMA Star/Mesh/Hybrid networks Multimedia, multiservice Efficient space segment utilization Easily expand network and site capability

78. Satellite Technology Options SCPC DAMA Frequency Time Frequency Time Sample when a SCPC system is cost-effective Sample when a DAMA system is cost-effective If is a number of sites in a VSAT Network One 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 Maxis 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.

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 Mbps More than 2 Mbps can be acommodated with the use of different IDU/IDU.

83. SCPC (single-carrier per channel) Copyright Maxis 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.

84. SCPC (single-carrier per channel) Copyright Maxis 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.

85. FDMA (Frequency Division Multiple Access) oldest method for channel allocation the satellite channel bandwidth is broken into frequency bands for different earth stations the 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); and CDMA (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 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

90. VSAT Topologies STAR - 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.

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.

95. STAR ARCHITECTURE (satellite’s perspective) VSAT VSAT Satellite HUB VSAT VSAT VSAT Topology of a STAR VSAT network viewed from the satellite’s perspective Note how the VSAT communications links are routed via the satellite to the Hub in all cases.

97. Since the traffic can go to or from any VSAT, this architecture is referred to as a MESH network.

99. MESH ARCHITECTURE (satellite’s perspective) VSAT VSAT VSAT VSAT Satellite VSAT VSAT VSAT VSAT VSAT VSAT Topology of a MESH VSAT network from the satellite’s perspective Note 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--comparison 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 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 Source: www.bhartibt.com

101. ADVANTAGES OF STAR Small uplink EIRP of VSAT (which can be a hand-held telephone unit) compensated for by large G/T of the Hub earth station Small downlink G/T of user terminal compensated for by large EIRP of Hub earth station Can be very efficient when user occupancy is low on a per-unit-time basis

102. DISADVANTAGES OF STAR VSAT terminals cannot communicate directly with each other; they have to go through the hub VSAT-to-VSAT communications are necessarily double-hop GEO STAR networks requiring double-hops may not meet user requirements from a delay perspective

103. ADVANTAGES OF MESH Users can communicate directly with each other without being routed via a Hub earth station VSAT-to-VSAT communications are single-hop. GEO MESH networks can be made to meet user requirements from a delay perspective.

104. DISADVANTAGES OF MESH Low EIRP and G/T of user terminals causes relatively low transponder occupancy With many potential user-to-user connections required, the switching requirements in the transponder will almost certainly require On-Board Processing (OBP) to be employed OBP is expensive in terms of payload mass and power requirements

106. One way transmission: ESSatelliteES: 2 x Range

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

114. Global Supply vs. Demand GEO Communications Satellites and Launches

115. VSAT: A Consistent Performer 160,000 140,000 120,000 100,000 80,000 60,000 40,000 20,000 - 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01

116. Opportunities in VSAT technology Voice over IP (VoIP) via satellite Frame Relay via satellite ATM via satellite Video-on-demand via satellite Multimedia application Internet/e-mail connection Telemedicine Distance 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.

118. Implementation Requirement Customers Locations Time Lines

119. Solution Details Frequency Band Outdoor Equipment Indoor Equipment Interfacing

120. Ground Antennas The size of the antenna depends on the satellite frequency band used, the data rate, and whether the service is bidirectional or receive only Higher data rates require larger antennas and/or higher power Higher 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 performance Receive-only antennas can be substantially smaller

121. Steps in Installation of a VSAT site Technical Site Survey Civil Work Antenna Mounting Pointing of Antenna Configuration of ODU

122. Steps in Installation of a VSAT site Configuration of Indoor Unit Testing on RF level Interfacing BER testing Integration (with the BTS/BSC)

123. Quality Assurance Tests BER testing Spectrum Analysis Carrier to Noise Ratio measurement

124. Common Faults/Problems Fading (due to rain etc.) LOS obstructions ODU/IDU malfunctions De-pointing of Antenna Interference

125. O & M Procedures Carrier Monitoring Spectrum Analysis Fault Diagnosis/Localization RF Power adjustment etc. etc.

126. Thank You!