2nd CnC Example CnC Ratio With Asymmetric Links | Mocomtech CDM-QX

CDM-Qx Satellite Modem	Revision 5
CnCPerformance Characterization	MN/CDMQx.IOM

D.8 2nd CnC Example: CnC Ratio With Asymmetric Links

Networks with asymmetric antennas are common with a larger antenna at one site (hub) and smaller ones at the other sites (remotes) and often have asymmetric data rates. In a number of links even a significant rain fade is not a big factor in CnC performance.

Some links, particularly C-Band or X-Band, have insignificant rain fades and the key to performance is setting both ends of the link to handle the asymmetry.

In asymmetric links, taking advantage of the available modulation and coding schemes is another tool for building efficient CnC links. In these links the ideal CnC ratio is 0 dB, but keeping the CnC ratio less than

7 dB, under all conditions, establishes links with margin. A link with a negative CnC ratio is also acceptable because the interfering signal is below the desired signal.

An asymmetric C-Band link is shown in Figure D-11. It has equal symbol rate carriers but the antenna at Site A is 4.5 meters antenna and Site B is 2.4 meters.

BW1

Asymmetric

Power

BW2

Asymmetric

Power

Conventional Carriers

CnC Carriers

Figure D-11. Asymmetric Link with the Same Data Rate but Different Antennas

Conventional side-by-side carriers are transmitted by the link on the left, and CnC carriers are deployed on the right. The conventional carriers are 8-PSK 2/3 TCM, and the CnC carriers are QPSK 3/4 Turbo. Notice that the bandwidth to support the two conventional carriers (BW1) is larger than the bandwidth for CnC (BW2), even though the conventional link uses 8-PSK 2/3 while CnC is QPSK 3/4. The benefit of CnC becomes apparent when it is realized that the bandwidth reduction possible with CnC is also accompanied by a reduction in power compared to the conventional link.

D–11

Image 253

Mocomtech CDM-QX operation manual 2nd CnC Example CnC Ratio With Asymmetric Links

Contents

Revision CDM-QxPage Acquisition range Errata aPage Errata B Page Rx Rs n/k ENT IESS-310 network 219/201 Errata CPage Tx Rs n/k ENT IESS-310 network 219/201 Errata DPage Part Number MN/CDMQx.IOM Revision January 20,2007 Customer Support Table of Contents Chapter Functional Description External Connections Comparison of all TPC Modes Evolution of TPC in Comtech Products Management Information Base MIB Files 11-1 About this Manual Electrical Safety International Symbols CE Mark Warranty Policy CDM-Qx Satellite Modem Revision Preface MN/CDMQx.IOM Xii CDM-Qx/QxL Introduction Features Software Flash Upgrading DoubleTalk Carrier-in-CarrierVerification Data Interfaces Remote ControlTurbo Product Coding Major Assemblies Assembly Description Fast Fast Options and Hardware Options Fast System Theory Fast Accessible OptionsImplementation Hardware Options Supporting Hardware and Software Compatibility Band CDM-Qx Satellite Modem Revision Introduction MN/CDMQx.IOM Unpacking Installation Mounting Optional Rear-Mounting Installation Bracket Installation of the Optional Mounting Brackets Select Internal if Loop ConfigurationConnect External Cables Observe the following Functional Description Page Modem Block Diagram Page Connections LED Front Panel Rear Panel Rear PanelPage Name Ref. Desig Connector Type Function Modem Rear Panel ConnectorsBNC IEC RF Output 75 or 50Ω 3 485/232 Connector 2 M&C 10/100BaseT ConnectorRemote Control Interface Connector Pin Assignments Use for 2-wire RS-485 operation Alarm Interface Connector Pin Assignments Alarms ConnectorPin # Signal Function Name Unbalanced G.703 Tx/Rx Connectors Balanced G.703 Connector Tx/Rx ConnectorBalanced G.703 Interface Connector Pin Assignments Pin # Signal Function Name Direction Pin # Generic Signal Description Direction RS-422 RS 7 RS-530 Data Interface ConnectorLvds RS-232 Circuit # Xx6. Quad E1 Data Interface J1 Connector Pin Assignments Quad E1 Data Interface Connectors AC Power Connector RX and TX if ConnectorsDC Power Connector AC Power Specifications Ground Connector This page is intentionally left blank Operation LED Front Panel LED IndicatorsColor Condition ENT Diamond Keypad Presently used on all UnitsCLR Modems Left-Hand Display AreaRight Hand Display Area TXF MD MD Redundancy Spectrum Analyzer Accessing the Display AreaRight-Hand Display Area RXS Principle Menu Tree Opening Screen Main Menu Config Monitor Test Info Save/Load Util ODUComtech EF Data CDM-Qx Firmware Version ODU Config Remote Tx Rx Group Frame Interface Ref Mask ODU Config Config„Remote„Serial Config„Remote Remote ControlConfig„Remote„Serial„Interface Config„Remote„Serial„Baudrate Config„Remote„Serial„Interface„RS485 RS-485 Bus AddressConfig„Remote„Ethernet Config„Remote„Ethernet„Address Config„Remote„Ethernet„GatewayConfig„Remote„Ethernet„MAC Config„Remote„Ethernet„SNMP Config„Remote„Ethernet„SNMP„Traps Config„Remote„Ethernet„SNMP„CommunitiesSnmp Trap Version ENT SNMPv1 SNMPv2 Trap Community , ENT comtechTrap IP Addr#1 ENT Trap IP Addr#2 ENT Tx FEC Mod Code Data Freq On/Off Pwr Scram Clk Inv Txα Config„Tx Transmit Config„Tx„Mod Modulation Scheme Config„Tx„FEC TX FEC TypeTx FEC Vit Vit+RS TCM+RS TPC Config„Tx„Data TX Data Rate Config„Tx„Code TX Code RateTx Code Rate 5/16 21/44 1/2 3/4 17/18 Tx Data Rate 05000.000kbps Sym02500.000ksps Tx if Freq 1156.3456 MHz Config„Tx„Freq TX if Frequency Tx if Freq 1156.3456 MHz RF=14156.3456 ENT Config„Tx„On/Off Transmit ON/OFF ControlTx Output State On Off RxTxInhibit Common , ENT Tx Common Output State Off On Config„Tx„Pwr„Manual Manual Mode Config„Tx„Pwr Transmit Power Level ModeConfig„Tx„Pwr„AUPC Aupc Mode Config„Tx„Pwr„AUPC MAX Range Config„Tx„Pwr„AUPC Target Eb/NoConfig„Tx„Pwr„AUPC Alarm Config„Tx„Pwr„AUPC DEMOD-UNLOCK Config„Tx„Scram Scrambler Config„Tx„Pwr„Combined Combined Transmit PowerConfig„Tx„Clk TX Clocking Mode Tx Inversion functions Spectrum Data Clock ,ENT Config„Tx„Inv TX Inversion FunctionsTx Spectral Inversion Normal Inverted Tx Data Sense Config„Rx Receive Config„Tx„Txα TX Roll-Off α factorTx Roll-off 20% 35% ENT RxFEC Demod Code Data Freq Acq Descram Buf Inv Misc CnC Rx FEC Vit Vit+RS Config„Rx„FEC RX FEC TypeTCM+RS Case Rules Comment Config„Rx„Code RX Code Rate Config„Rx„Demod Demodulation SchemeDemodulation Bpsk Qpsk 8-PSK 16-QAM Rx Code Rate 5/16 21/44 1/2 3/4 7/8 17/18 Rx Data Rate 05000.000kbps Sym02500.000ksps Config„Rx„Data RX Data Rate Config„Rx„Acq Demod Acquisition Range Config„Rx„Freq RX FrequencyRx if Freq1156.3456 MHz RF=12156.3456 ENT Demod Acquisition Range Config„Rx„Buf RX Buffer Clock Source Config„Rx„Descram DescramblerENT Config„Rx„Misc Rx Miscellaneous Config„Rx„Inv RX Inversion Functions Config„Rx„Misc„Rxα RX Roll-Off α factor Config„Rx„Misc„EbNo Eb/No AlarmConfig„Rx„CnC CARRIER-IN-CARRIER→ Config„Rx„CnC„FrqOffs CnC Frequency Offset Config„Rx„CnC„Mode CnC→ Mode of OperationPlease Check TX Power Level Please Wait Config„Rx„CnC„ReAcq CnC RE-ACQUISITION Time Config„Rx„CnC„SrchDelay CnC Search DelayConfig„Group Grouping MOD/DEMOD Cards Config„Group„Modem Config„Group„Redundancy„Config Config„Group„RedundancyConfig„Group„Redundancy„Config „11 Config„Group„Redundancy„Config „12 Config„Group„Redundancy„Mode„Manual Config„Group„Redundancy„ModeConfig„Frame Framing Mode Config„Frame„Unframed Unframed Framing mix AUPC-Only Edmac ModeAUPC+EDMAC Master Slave Distant-end Base Address Config„Frame„D&I++ D&I++0240 Address This Slave Unit ENT Interface RS422 V.35 RS232 Config„Interface Data InterfaceHssi ASI G.703 QDI None RTS/CTS operation , ENT Loop,RTS Controls Tx Out HDB3 AMI 703 E1 Line Code HDB3 AMI , ENT T1 Line Length Feet HDB3 AMI Config„Mask Mask Config„Ref Reference OscillatorAlarm Mask Transmit Receive Reference BUC LNB ,ENT Frequency Reference Internal MHz ENT Tx-FIFO Alarm ENT Active Masked Tx Alarm Mask Tx-FIFO BPV Tx-AIS ENTRx Alarm Mask AGC Eb/No Rx-AIS Buffer AGC Alarm BUC Alarm Reference AlarmLNB Alarm Config„ODU„BUC Block Upconverter BUC Config„ODU Outdoor Unit for L-Band Unit OnlyODU BUC LNB Config„ODU„BUC„M&C-FSK„Address FSK Comms Config„ODU„BUC„M&C-FSK M&C FSKConfig„ODU„BUC„M&C-FSK„Address FSK Address BUC M&C Config„ODU„BUC„DC-Pwr BUC DC Power Config„ODU„BUC„M&C-FSK„Tx-On/Off FSK TX-ON/OFFConfig„ODU„BUC„10MHz BUC 10MHz Config„ODU„BUC„Alarm BUC Alarm BUC Current Alarm Upper Limit1200mA Config„ODU„BUC„Delay BUC DelayBUC Current Alarm Lower Limit1200mA Power-On Delay Config„ODU„BUC„Mix BUC MIX Config„ODU„BUC„LO BUC LO Config„ODU„LNB„Voltage LNB Voltage Config„ODU„LNB LNBLNB DC Config„ODU„LNB„10MHz LNB 10MHz Config„ODU„LNB„Power-On/Off LNB POWER- ON/OFFConfig„ODU„LNB„Alarm LNB Alarm Config„ODU„LNB„Mix MIX Config„ODU„LNB„LO LOLNB Current Alarm Lower Limit 050mA ENT LNB Frequency Mix Monitor„Alarms„Unit Unit Alarms Monitor„Alarms Alarms Monitor„Alarms„Transmit Transmit Alarms Monitor„Alarms„Receive Receive AlarmsMonitor„Alarms„ODU Outdoor Unit Alarms Monitor„Event-Log EVENT-LOG or Stored Events Monitor„Rx-Params RECEIVE-PARAMETERS Monitor„Event-Log„View View Stored Events Log 023 30/11/02 Fault Demod Lock 3 ,ENTLog 024 30/11/97 Clear Demod Lock 3 ,ENT Monitor„Stats Link Statistics for grouped as modem only Link Statistics View Clear-All Config ENTMonitor„Stats„View View Link Statistics Stats Logging Interval Disabled,ENT Monitor„Stats„Config Configure StatsMonitor„Stats„Clear-All Clear ALL Stats Clear all Stored Stats? No Yes Monitor„CnC Monitor CARRIER-IN-CARRIER CnC Monitor„AUPC Monitor AUPCfor grouped as modem only ODU LNB Monitor„ODU Monitor ODU for L-Band Unit only Mode Norm if 2 Dig 2 I/O 2 RF Tx-CW Tx1-0 ENT Test Mode Bist ENT Spec-AnalyzerTest TX-CW Norm If Loop Dig Loop RF LoopTX-1,0 Bert Config Tx=ON Rx=ON Tx-Pat=2047 Rx-Pat=2047 Bist BERT-Config BERT-Mon BERT-Control ENTBert Monitor Errs=0000253 BER=8.5E-07 Bert Control 10E-3Err=OFF Restart=NO SyncThres=256 Spectrum Analyzer Mode Mode ConfigConfig Spectrum Analyzer CenterFreq Span Spectrum Analyzer If Loopback Info Information Info„Rem Remote Control InformationInfo Rem Tx Rx Buffer Frame Interface Mask Ref ID Tx 1140.000 05000.000 TUR 8P 17/18 S EXT -20.0 on N Info„Tx TX InformationTx C N N Rx 1140.000 05000.000 TUR 8P 17/18 D RX BUF +/-32k N Info„Rx RX InformationRx C N N Demod Sweep Acquisition range Info„Buffer Buffer Information Buffer Enabled Tx=Rx ENTInfo„Frame Framing and Edmac Information Info„Interface Interface Information Info„Ref Frequency Reference Info„Mask Alarm Mask InformationInfo„ID Circuit Identification Character TST Message No YES Save/Load„Save Save Configuration New Config has been Loaded From Location Save/Load„Load Load ConfigurationEmpty ENT Contains No Data! ENT Utility„Clock REAL-TIME Clock Utility„RxBuffer Buffer RecenterUtility RxBuffer Clock Ref ID Display Firmware Fast Real-Time Clock , ,ENT Time=120000 Date24/04/03 Warm-up delay ENT Utility„Ref Reference AdjustUtility„ID Circuit Identification Internal Freq Utility„Firmware Firmware Utility„Display Display Brightness Update Cpld to v1.x.x? No Yes ENT Current Active Image #1 Next Reboot Image #1 #2Programming Cpld Fast Utility„FAST Fast Code Options Edit 20 digit Fast Code 00000000000000000000 ENT View Options ENT Redun Not Installed Forward Error Correction Options Viterbi Decoding Summary ViterbiFor Against Reed-Solomon Outer Codec Concatenated R-S Coding Summary Closed Network Modes PSK/TCM Coding Summary Trellis Coding Evolution of TPC in Comtech Products Turbo Product Codec Hardware Option Introduction Turbo Product Coding processing delay comparison End-to-End Processing DelayAvailable TPC Modes Comparison of all TPC Modes Turbo Product Coding Summary BER Viterbi Decoding Viterbi with Decoding, with PSK/TCM Rate 2/3Without 219, 201 RS Outer Code Comtech Turbo Product Codec Rate 3/4 QPSK, 8-PSK 16-QAM CDM-Qx Satellite Modem Forward Error Correction Options Comtech Turbo Product Codec Rate 7/8 QPSK, 8-PSK 16-QAM Comtech Turbo Product Codec BPSK/QPSK Rate 21/44 Bpsk and Rate 5/16 Bpsk Turbo BER Page Theory Of Operation Edmac Channel M&C Connection Setup Summary This page is intentionally left blank Automatic Uplink Power Control Target Eb/No Setting Aupc ParametersMax Range Demod Unlock AlarmCompensation Rate Monitoring DoubleTalk Carrier-in-Carrier Page Transponder Utilization with and without CnC→ Page Redundancy CDM-Qx Satellite Modem Revision Redundancy MN/CDMQx.IOM 10-2 Ethernet Management Interface Protocols Management Web Web Server Http Interface Web Server Menu Tree Web Server Menu TreeLevel 11-4 11-5 11-6 11-7 Management Information Base MIB Files Snmp Interface Snmp Traps Snmp Community Strings Telnet Interface Alarms and Faults SNMPv2 notifications 11-11 11-12 Page Page FEC Modulator Referred to symbol rate Power Spectral DensityComtech EF Data CDM-Qx Transmit Viterbi DemodulatorPSK/TCM Codec Turbo Product Modulation HIGHER-ORDERCoding Hssi Automatic Uplink Power Control Future Data Rate Ranges Miscellaneous Framing Summary FutureFCC Page Appendix B. Flash Upgrading Ethernet FTP upload procedure Construction Sector CDM-Qx Satellite Modem Revision Flash Upgrading MN/CDMQx.IOM RS-485 Appendix C. Remote Control Basic Protocol RS-232 Start Of Packet Packet StructureController-to-target Example 0135/TRQ=70.2345CR Target-to-controller Instruction Code AddressSlot Address ‘=’ code Target to Controller is used in two ways Instruction Code Qualifier $ code target-to-controller is only used as follows Message Arguments Remote CommandsEnd Of Packet CDM-Qx Satellite Modem Revision Remote Control MN/CDMQx.IOM TX Remote Commands TCR? TCR=TCR TCR# TSI= TSI? TSI=TSI TSI# TSI$ TCK= TCK? TCK=TCK TCK# RFQ= RFQ? RFQ=RFQ RFQ# RFQ$ RMD= RMD? RMD==BPSK RMD =QPSK RMD# RDR= RDR? RDR=RDR RDR# RSW= RSW? RSW=RSW RSW# EBA= EBA? EBA=EBA EBA# EBA$ ITF= ITF? ITF=ITF ITF# ESA= ESA? ESA=ESA ERF= TST= TST? TST=TST TST# AUP= AUP? AUP=AUP AUP# LBO= LBO? LBO=LBO LBO# HHC= HssiHHC? HHC Applies to CST? CST=CST CST# TIM= TIM? TIM=TIM TIM# IRM = IRM? IRM=IRM IRM# FBU= FBU? FBU=FBU FBU# CSD? CSD=CSD CSD# EID? Query Commands UID? Bytes FLT? =Change in fault REB? WHO? RNE= CC is Fault Code numbers, as in FLT? Or Infor Code, which RNS=CR RX BER RSL?CRM? CDM? SWR? CFM?FRW? IMG= IMG? IMG=IMG IMG# ITP? Bulk Commands OGC= OGC? OGC=OGC OGC# BAD= Arguments For Command or Response to QueryBand Unit Only BCH= BOE=BCL= BUC LO BLO= BUT? BUCBPA? BSV? Control Band Unit Only Parameter Instruction Type Code Qualifier LNB Power Parameter Instruction Type Code Qualifier Parameter Command Instruction Type Code Qualifier BCT= BCT? BCT=BCT# BCT$ SPF= SPM=SPS= SPM= SPM? DNI= DNI? DNI# DNI$ DNI DNI= DTS= Parameter Instruction Type Code Qualifier Drop TimeslotApplies to Cards grouped As modem CDM-Qx Satellite Modem Revision Remote Control MN/CDMQx.IOM Carrier-in-CarrierDescription Performance Characterization Figure D-1. Adjacent Carrier a As Tested and BAs Plotted Degradation Due To Carrier Spacing 20% Rolloff Carrier Spacing ForDegradation ≤ 0.5 dB Carrier Spacing For 35% Rolloff PSK 3/4 Turbo, α = 35% Figure D-5. Adjacent Carrier Cases Selecting The Adjacent Carrier Curve Carrier-in-Carrier Ratio CnC Ratio Curve To Use In Figure D-2, ErrorCase Desired Adjacent Carrier Found., or D-4 Figure D-7. CnC Ratio For Qpsk and 8-PSK CnC Carrier Offset Symbol Rate Ratio1st CnC Example Adjacent Carriers, CnC Ratio and Rain Fade Site a Site B DL Fade UL Fade Site a Site BComment Per Figure D Figure D-10. Link With Fading At Site a 2nd CnC Example CnC Ratio With Asymmetric Links Parameters Site a Site B Link parameters and results are summarized in the table Eb/No Degradation At Site a Parameter Due To Fade At 3rd CnC Example Asymmetric Link With Rain FadePer Figure D- Qpsk Eb/No Degradation At Site B Parameter Due To Fade At Conclusion Metric Conversions 480 333 2200 Phone 480 333 2161 FAX