INTERACTIVE VSATS
Typical Equipment

Introduction

Overview of Technology

Shared Hub Networks

Mini Hub Networks

Network Management

Virtual Subnetworks

TDM/TDMA Interactive VSAT Networks

Network Configuration
Signal Types and Characteristics
TDM/TDMA Connection Set Up
Hub Station
Remote Terminals

Demand Assigned SCPC Interactive VSAT Networks

Network Configuration
Signal Types and Characteristics
Hub Station
Remote Terminals

CDMA Interactive VSAT Networks

Network Configuration
Signal Types and Characteristics
Hub Station
Remote Terminals

Typical Interactive VSAT Equipment

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Typical Interactive VSAT Equipment

Typical VSAT Characteristics
Supplier Gilat/Spacenet Hughes
Model Skystar Advantage Personal Earth Station/Integrated Satellite Business Network
Outbound data 64, 128, 192, 256, 512, 1024, 2048 kb/s 128 or 512 kb/s
Outbound access S-TDM** TDM
Outbound coding rate 1/2 or 1/4 convolutional FEC (k=7) rate 1/2 FEC
Outbound modulation BPSK or QPSK BPSK
Inbound data 9.6, 19.2, 38.4, 56, 64, 128 kb/s (DPSK) 38.4, 76.8 kb/s (MSK) 64, 128 or 256 kb/s
Inbound access modified slotted ALOHA (random access) with Automatic Dedicated Access (reservation mode)*** TDMA
Inbound coding rate 1/2 convolutional FEC (k=7) rate 1/2 FEC
Inbound modulation DPSK or MSK BPSK
Transmit frequency   14.0 to 14.5 GHz C band Ku band
Receive frequency 3.70 to 4.26, 4.50 to 4.80 GHz 10.9 to 12.75 GHz in 3 bands C band Ku band
Hub    
Antenna diameter 11 m 5.6 or 7.2 m 5.6 to 9 m
Tracking    
HPA 75 W TWTA  
Noise temperature    
IF 70 ± 18 MHz or140 ± 36 MHz  
Frequency control    
Pilot    
Uplink power control    
Capacity up to 8000 remote ports  
Hub Interface    
Hub port rates 110 b/s to 256 kb/s to 19.2 kb/s asynch, 1.2 to 64 kb/s synch
Number of hub ports up to 48 X.25 ports up to 12 Token Ring or Ethernet ports up to 60 voice ports  
Hub port types RS-232, RS-422, Token Ring, Ethernet, telephony RS-232, RS-422, V.35, 4-wire
Protocols SDLC, X.25, Token Ring, Ethernet  
Indoor Unit    
Ports 2, 4 or 8 32 with multiport option
Data rates 50 b/s to 64 kb/s to 19.2 kb/s asynch, 1.2 to 64 kb/s synch, Ethernet 10 Mb/s, Token Ring 4/16 Mb/s
Port types RS-232, Token Ring, Ethernet, telephony RS-232, RS-422, V.35, RS-530, Ethernet (UTP, coaxial), Token Ring (Type 1, Type 3), RJ-11, 4 wire E & M
Protocols X.3/X.28/X.29, X.25 (SVC and PVC), TNPP, T3POS, SNA/SDLC (PU2.0, PU4.0, PU2.1), BSC 3270, BSC 2780/3780, Ethernet (IEEE 802.3), Token Ring (IEEE 802.5), TCP/IP over LAN (IP router over MAC, TCP gateway), SNA over LAN (LLC/TR, LLC/Ethernet) SDLC, X.25, Burrough's Poll Select, BSC 3270, TINET, Bit and Byte Transparent, HASP, DDCMP, Frame Transparent, X.3/X.28 PAD, Broadcast, Ethernet, Token Ring, Transparent Bridging and others
Telephony subscribers    
Telephony interfaces    
Signalling FXO, FXS  
Speech coding proprietary  
Speech coding rate 4.8, 6.4 kb/s  
Fax    
Fax modem rate 2.4, 4.8 kb/s*  
Data modem rate    
Dimensions 40 (d) x 6 (h) x 30 (w) cm 15 x 48 x 41 cm
Outdoor Unit    
Antenna diameter 1.8 m 0.95, 1.2 m 1.8, 2.4 m 0.75, 1.0, 1.2, 1.8, 2.4 m
HPA   2, 5 W 0.5, 1.0, 2 W
Noise figure    
IF 950 - 1450 MHz  
Dimensions    

* optional, ** statistical TDM (this is the same as the TDM used by other TDM/TDMA VSAT manufacturers, but Gilat/Spacenet use a different name), *** this is a proprietary hybrid of FDMA and Slotted Aloha TDMA

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Typical VSAT Characteristics (continued)
Supplier Indra Espacio NEC
Model Arcanet Nextar-V
Outbound data   64, 128, 256, 512, 768, 1536, 2048* kb/s
Outbound access BLQS-CDMA TDM
Outbound coding   rate 32/75 FEC, viterbi decoding
Outbound modulation   BPSK/QPSK
Inbound data   64, 128, 256* kb/s
Inbound access BLQS-CDMA AA/TDMA
Inbound coding   rate 1/2 FEC, viterbi decoding
Inbound modulation   BPSK/QPSK
Transmit frequency   5.925 to 6.425 or 5.850 to 6.350 GHz 14.0 to 14.5 GHz
Receive frequency   3.700 to 4.200 or 3.625 to 4.125 GHz 10.95 to 11.20, 11.45 to 11.70, 11.70 to 12.20, 12.25 to 12.75 GHz
Hub    
Antenna diameter   4.5 to 11 m
Tracking    
HPA   10 W to 1 kW 6 W to 1 kW
Noise temperature   55 K 180 K
IF    
Frequency control    
Pilot    
Uplink power control    
Capacity    
Hub Interface    
Hub port rates   50 bps to 64 kb/s
Number of hub ports   36 max
Hub port types   RS-232, V.35, EIA-530, IEEE 802.3 (10base5)
Protocols   Frame Relay, TCP/IP (IP Router), X.25, SNA/SDLC, X.3, PAD, BSC 3270/3780
Indoor Unit    
Ports   2 or 4 (16 max with expansion IDUs)
Data rates   50 bps to 64 kb/s
Port types   RS-232, V.35, EIA-530, IEEE 802.3 (10base5)
Protocols   Frame Relay, TCP/IP (IP Router), X.25, SNA/SDLC, X.3, PAD, BSC 3270/3780
Telephony subscribers    
Telephony interfaces    
Signalling DTMF  
Speech coding G.278 and TIA IS-54 VSELP  
Speech coding rate 16 kb/s (G.728) and 8 kb/s (VSELP)  
Fax    
Fax modem rate 2.4 kb/s  
Data modem rate 2.4, 4.8 kb/s  
Dimensions    
Outdoor Unit    
Antenna diameter   0.95, 1.2, 1.8, 2.4 m
HPA   3.3, 20 W 0.5, 1, 2 W
Noise figure   60 K 140 K
IF    
Dimensions    

* QPSK only

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 Typical VSAT Characteristics (continued)
Supplier STM TSAT
Model X.Star (TXR-3000) TSAT 2000
Outbound data 64, 128, 256, 512, 1024, 1544 kb/s 300, 600 1200 b/s 2.4, 4.8 kb/s
Outbound access TDM TDM
Outbound coding rate 1/2 FEC rate 1/2 rate 1/2, 3/4*, 7/8*
Outbound modulation burst BPSK Trellis encoded 4FSK 2-4PSK
Inbound data 96, 192, 384 kb/s 300, 600 1200 b/s 2.4, 4.8 kb/s
Inbound access FA/TDMA, slotted Aloha contention, dynamic allocation, slotted Aloha with dynamic bandwidth allocation TDMA or modified slotted ALOHA
Inbound coding rate 1/2 FEC rate 1/2 rate 1/2, 3/4*, 7/8*
Inbound modulation BPSK Trellis encoded 4FSK 2-4PSK
Transmit frequency 14.0 to 14.5 GHz 14.0 to 14.5 GHz
Receive frequency 12.5 to 12.75 GHz 10.95 to 11.75 GHz and 12.5 to 12.75 GHz
Hub    
Antenna diameter   1.2, 1.8, 2.4 m
Tracking   none
HPA    
Noise temperature    
IF 70 or 140 MHz  
Frequency control    
Pilot    
Uplink power control    
Capacity    
Hub Interface    
Hub port rates    
Number of hub ports   2 (RS 232) + 1 (X.25)
Hub port types   RS 232, RS 422/485
Protocols   asynch, X.25, Hayes AT
Indoor Unit    
Ports 5 - 17 2 (RS 232) + 1 (X.25)
Data rates to 64 kb/s 110 to 9600 bps
Port types RS 232C, X.21, V.35 RS 232, RS 422/485, X.25
Protocols X.25, X.3/X.28/X.29, SNA/SDLC, BSC, asynch, ALC, DDCMP, HDLC, digitised voice, ADCAP, synch, TCP/IP, fax, 3201, transparent, Ethernet 802.3 asynch, X.25, Hayes AT
Telephony subscribers   n/a
Telephony interfaces 4W E & M, 2W loop start (OPX or SLT) n/a
Signalling   n/a
Speech coding   n/a
Speech coding rate 7.2, 9.6, 12, 14.4, 16 kb/s n/a
Fax Group 3 n/a
Fax modem rate 2.4 to 9.6 kb/s n/a
Data modem rate   n/a
Dimensions 46 (w) x 53 (d) x 18 (h) cm 46 (h) x 17.5 (w) x 19 (d) cm
Outdoor Unit    
Antenna diameter 1.2, 1.8, 2.4 m 0.55, 0.9, 1.2 m
HPA 1, 2, 4 W SSPA 0.1, 0.5, 1 W
Noise figure 2.2 dB  
IF 950 to 1450 MHz  
Dimensions   6 (h) x 9 (w) x 16.5 (d) cm

* optional

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Typical VSAT Characteristics (continued)
Supplier TSAT ViaSat
Model TSAT 2100 SkyRelay
Outbound data 2.4 - 9.6 kb/s 14.4 kb/s 16.8 kb/s 64, 128, 256 kb/s
Outbound access TDM  
Outbound coding rate 1/2 rate 3/4 rate 7/8 rate 1/2 convolutional
Outbound modulation O-QPSK BPSK, QPSK, CPFSK
Inbound data 2.4 - 9.6 kb/s 14.4 kb/s 16.8 kb/s 64, 128, 256 kb/s
Inbound access TDMA or modified slotted ALOHA  
Inbound coding rate 1/2 rate 3/4 rate 7/8 rate 1/2 convolutional
Inbound modulation O-QPSK BPSK, QPSK, CPFSK
Transmit frequency 14.0 to 14.5 GHz 5.925 to 7.025 GHz 14.0 to 14.5 GHz
Receive frequency 10.95 to 11.75 GHz and 12.5 to 12.75 GHz 3.7 to 4.8 GHz 10.95 to 12.75 GHz
Hub    
Antenna diameter 1.2, 1.8, 2.4 m  
Tracking none  
HPA    
Noise temperature    
IF   70 ± 18 MHz, 140 ± 36 MHz optional
Frequency control   100 kHz steps
Pilot    
Uplink power control    
Capacity    
Hub Interface    
Hub port rates   2.4 to 38.4 kb/s asynch
4.8 to 64 kb/s synch
Number of hub ports 2 (RS 232) + 1 (X.25) up to 24 per Network Access Module
Hub port types RS 232, RS 422/485 RS-232, V.35 optional, RS-530 optional, LAN
Protocols asynch, X.25, Hayes AT SNA/SDLC-PU type 2 and 2.1, 2780/3780 BSC, X.25, asynch (X.3, X.28, X.29), IP routing
Indoor Unit    
Ports 2 (RS 232) + 1 (X.25) 6 (14 with optional port expander card)
Data rates 110 to 9600 bps 1.2, 2.4, 4.8, 9.6, 19.2, 38.4, 56, 64, 128 kb/s
Port types RS 232, RS 422/485, X.25 RS-232C, V.35, RS-449, V.11
Protocols asynch, X.25, Hayes AT SDLC 3270/5250, X.25, X.3, X.28, X.29, 3270 BSC, 2780/3780 BSC, 10Base T, 10Base 2, IP
Telephony subscribers n/a n/a
Telephony interfaces n/a n/a
Signalling n/a n/a
Speech coding n/a n/a
Speech coding rate n/a n/a
Fax n/a n/a
Fax modem rate n/a n/a
Data modem rate n/a n/a
Dimensions 46 (h) x 17.5 (w) x 19 (d) cm 9.5 (h) x 43.5 (w) x 38.7 (d) cm
Outdoor Unit    
Antenna diameter 0.55, 0.9, 1.2 m 0.95, 1.2, 1.8, 2.4 m
HPA 0.1, 0.5, 1 W +34 dBm ± 1 dB +29 dBm ± 1 dB
Noise figure    
IF   950 to 1700 MHz
Dimensions 6 (h) x 9 (w) x 16.5 (d) cm  

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