1、Problem Solvers to the Telecommunications IndustryCommittee T1 -TelecommunicationsTechnical Report No. 59September 1999Single-CarrierRate AdaptiveDigital Subscriber Line(RADSL)Prepared by T1E1.4Working Group onDigital Subscriber Line (DSL) AccessCopyright 1999 by Alliance for Telecommunications Indu
2、strySolutionsAll rights reserved.Committee T1 is sponsored by the Alliance for TelecommunicationsIndustry Solutions (ATIS) and accredited by the American NationalStandards Institute (ANSI)No part of this publication may be reproduced in any form,in an electronic retrieval system or otherwise, withou
3、t theprior written permission of the publisher.Technical Report No. 59Single-Carrier Rate AdaptiveDigital Subscriber Line (RADSL)Document T1E1.4/99-161R3Prepared byT1E1.4Working Group on Digital Subscriber Line (DSL) AccessThis page intentionally left blank.- i -Table of Contents1. Scop e and Purpos
4、e 11.1 S COPE . 11.2 P URPOSE . 12. References . 13. Definitions, Abbreviations, Symbols and Acronyms 33.1 D EFINITIONS 33.2 A BBREVIATIONS , SYMBOLS AND ACRONYMS . 44. Reference Models 84.1 S YSTEM R EFERENCE M ODEL 84.2 G ENERAL RADSL T RANSCEIVER S YSTEM M ODEL 84.3 S ERVICE C LASS D EFINITION .
5、95. Single-Carrier RADSL Physical Layer Descriptions . 95.1 S YSTEM M ODEL 95.1.1 Single-Carrier RADSL System Block Diagram and Input/Output Stream Format 105.1.2 Functional Transmitter Reference Model . 105.1.2.1 Common . 105.1.2.2 Profile Map of T ransmitter Functionality . 125.1.2.3 Profiles . 12
6、5.2 P HYSICAL M EDIUM D EPENDENT (PMD) S UBLAYER 145.2.1 PMD Scrambling . 145.2.1.1 Frame Lo cked . 145.2.1.2 Bypass PMD Scrambling . 175.2.2 Coding 175.2.2.1 Constellation Encoder . 175.2.2.1.1 2 D8S Trellis Code . 175.2.2.1.2 Differential/Gray . 215.2.2.2 Tomlinson Precoder 245.2.3 Modulation 245.
7、2.3.1 Block Diagrams 245.2.3.2 Symbo l Rates 255.2.3.2.1 Mandatory Symbol Rates 255.2.3.2.2 Optional CAP Symbol Rates . 255.2.3.2.3 Optional QAM Symbol Rates 265.2.3.3 Tra nsmitter Spectrum 265.2.3.3.1 Mandatory Center Frequencies 265.2.3.3.2 Optional QAM Center Frequencies 275.2.3.4 PSD Mask descri
8、bes the line modulation and the spectral composition of signals transmitted by both RADSLTransceiver Unit at the Central office (ATU-C) and that at the remote location (ATU-R); describes the receive signals at both the ATU-R and ATU-C; describes electrical and mechanical specifications of a network
9、interface; describes a common logical interface to the ATM-TC, Packet-TC, Bit-Synchronous-TC and EOC-TC sublayers; describes operation and maintenance communications over an Embedded Operations Channel(EOC); describes the exchange of information sequences during start-up to establish systemconfigura
10、tion and transmission link; and describes performance objectives and test procedures.2. ReferencesITU-T (CCITT) Recommendation V.32 (1988), A Family of 2-Wire, Duplex Modems Operating at DataSignaling Rates of up to 9600 Bit/S for Use on the General Switched Telephone Network and on LeasedTelephone-
11、Type CircuitsANSI T1.231-1997, American National Standard for Telecommunications - Digital Hierarchy - Layer 1 In-Service Digital Transmission Performance MonitoringTECHNICAL REPORT NO. 59- 2 -ANSI T1.401-1993, American National Standard for Telecommunications - Interface between Carriersand Custome
12、r Installations - Analog Voice-Grade Switched Access Lines Using Loop-Start and Ground-Start SignalingANSI T1.413-1995, American National Standard for Telecommunications - Network and CustomerInstallation Interfaces - Asymmetric Digital Subscriber Line (ADSL) Metallic InterfaceANSI T1.413-1998, Amer
13、ican National Standard for Telecommunications Network and CustomerInstallation Interfaces Asymmetric Digital Subscriber Line (ADSL) Metallic InterfaceANSI/EIA/TIA-571-1991, Environmental Considerations for Telephone TerminalsANSI/EIA RS-422A-1978, Electrical Characteristics of Balanced Voltage Digit
14、al Interface CircuitsY. Chen, G. H. Im, and J. J. Werner, “Design of Digital Carrierless AM/PM Transceivers,” AT removed for DSL use.Net data rate The total data rate that is available to user data in any one direction.POTS splitter A low-pass/high-pass pair of filters that separate high (RADSL) and
15、 low (POTS)frequency line signals.Splitter A low-pass/high-pass pair of filters that separate high (RADSL) and low (POTS)frequency signals.Upstream ATU-R to ATU-C direction (customer to network direction).Voice band The 0.3 to 3.4 kHz frequency band, based on Bellcore local switching sy stemsgeneric
16、 requirement (LSSGR) and transmission system generic requirement(TSGR) specifications.TECHNICAL REPORT NO. 59- 4 -3.2 Abbreviations, symbols and acronyms Exclusive-or; modulo-2 additionAAL1 ATM Adaptation Layer 1ADSL Asymmetric digital subscriber lineAGC Automatic Gain ControlAIS Alarm Indication Si
17、gnalAM Amplitude modulationANSI American National Standards InstituteAOC ADSL Overhead Control Channe lATM Asynchronous Transfer ModeATU ADSL/RADSL Transceiver UnitATU-C ADSL/RADSL Transceiver unit, central office endATU-R ADSL/RADSL Transceiver unit, remote terminal endBB BroadbandBC Byte CountBER
18、Bit error ratioBERT Bit error ratio testbps or bits/s Bits per secondCAP Carrierless Amplitude and Phase modulationCBR Constant Bit RateCI Customer InstallationCLP Cell Loss PriorityCO Central OfficeCPE Customer Premise EquipmentCRC Cyclic Redundancy CheckCSA Carrier Serving AreadBm dB reference to
19、1 milliWatt, i.e., 0 dBm = 1 milliWattDCM Direct Cell MappingDPM Direct Packet MappingDS DownstreamDSL Digital Subscriber LineEDC Error Detection CodeEOC Embedded Operations ChannelERL Echo-Return Loss, as defined by IEEE Std 743-1984ES Errored SecondFAW Frame Alignment WordFDM Frequency-division mu
20、ltiplexingFEBE Far-End Block ErrorTECHNICAL REPORT NO. 59- 5 -FEC Forward Error CorrectionFERF Far-End Receiver ErrorFEXT Far-end crosstalkFM Frequency ModulationGF Galois fieldGFC Generic Function CodeHDSL High-bit- rate Digital Subscriber LineHEC Header Error CheckID code Vendor identification cod
21、eISDN Integrated services digital networkITU International Telecommunication Unionkbit/s Kilobits per secondkbps Kilobits per secondLOCD Loss-of-Cell DelineationLOF Loss of frameLOM Loss of Maintenance cellsLOS Loss of signalLSB Least Significant BitMbit/s Megabits per secondMbps Megabits per second
22、MBS Monitored Block SizeMSB Most significant bitMSB Most Significant ByteMSE Mean squared errorNB NarrowbandNEXT Near-end crosstalkNI Network interfaceNIC Number of Included CellsNMB Number of Monitored BlocksNT Network terminationOA services using the voice bandTECHNICAL REPORT NO. 59- 6 -PRBS Pseu
23、do-random bit seque ncePSD Power Spectral DensityPSN PL-OAM Sequence NumberPSTN Public Switched Telephone NetworkPTC Physical Transmission Convergence sub-layerPTI Payload Type IndicatorQAM Quadrature amplitude modulationQPSK Quadrature phase shift keyingRADSL Rate-A daptive Asymmetrical Digital Sub
24、scriber LineRDI Remote defect indicationRFI Remote failure indicationRS Reed-SolomonRT Remote TerminalRX Receive/receiverRXD-DS Received data, downstreamRX-DS-EOC Receive downstream EOCRX-DS-F Receive Downstream Fa st streamRX-DS-I Receive Downstream Interleaved streamRXD-US Received data, upstreamR
25、X-US-EOC Receive upstream EOCRX-US-F Receive Upstream Fast streamRX-US-I Receive Upstream Interleaved streamS/P Serial-to-ParallelSER Symbol error ratioSES Severel y Errored SecondSM Service ModuleSNR Signal-to-Noise RatioSONET Synchronous Optical NetworkSRL high SRL in a band from approximately 220
26、0 to 3400 HzSRL low SRL in a band from approximately 260 to 500 HzSRL Singing Return Loss, as defined by IEEE Std 743-1984SSS Self-Synchronizing ScramblerSTM Synchronous Transfer ModeT Interface(s) between ATU-R and CI or home network)TBD To be determinedTC Transmission Convergence sublayerTP Transm
27、ission PathT-SM Interface(s) between ATU-R and SM(s)TECHNICAL REPORT NO. 59- 7 -T-SM, T-sm Interface(s) between ATU-R and SM(s)TX Transmit/transmitterTXD-DS Transmitted data, downstreamTX-DS-EOC Transmit downstream EOCTX-DS-F Transmit Downstream Fast streamTX-DS-I Transmit Downstream Interleaved str
28、eamTXD-US Transmitted data, upstreamTX-US-EOC Transmit upstream EOCTX-US-F Transmit Upstream Fast streamTX-US-I Transmit Upstream Interleaved streamU-C Loop Interface Central Office endU-R Loop Interface Remote Terminal endUS UpstreamUTC Unable to complyV Logical interface between ATU-C and a digita
29、l network element such as one or moreswitching systemsVCI Virtual Channel IdentifierVPI Virtual Path IdentifierX The logical interface between ATU-C and the POTS splitterTECHNICAL REPORT NO. 59- 8 -4. Reference Models4.1 System Reference ModelThe system reference model shown in Figure 1 illustrates
30、the physical blocks required to provide RADSLservice.DigitalNetwork(s)T-smVPOTSSplitterPOTSSplitterU-C U-RPSTN POTSATU-C ATU-R SMNOTES:1. The V interface is defined in terms of logical functions, not physical functions.2. The V interf ace may consist of interface(s) to one or more switches.3 Impleme
31、ntation of the V and T-sm interfaces is optional when interfacing elements areintegrated into a common element.4. The splitter function, or a portion thereof, may be integrated within the ATU.5. A digital carrier facility (e.g., SONET) may be interposed at the V interfacewhen the ATU-C is located at
32、 a remote site.6. More than one type of T-sm interface may be defined, and more than one type of T-sminterface might be provided fro m an ATU-R.Figure 1 - RADSL Functional Reference Model4.2 General RADSL Transceiver System ModelFigure 2 shows the layering structure used to describe the functionalit
33、y of the ATU-R and ATU-C. ThePMD sub-layer defines the functionality associated with modulation and demodulation of the line signal.The PTC sub-layer provides framing, channelization, and forward error correction. The higher entity TCsub-layers (ATM-TC, Packet TC, Bit synchronous TC, and EOC TC) int
34、erface the corresponding higherlayer protocols to the physical layer.TECHNICAL REPORT NO. 59- 9 -PMDPTCATMTCPacketTC EOCTCSplitterPMDPTCSplitterPSTN POTSU-C U-RCustomer Premises End ATMTCPacketTCBit Sync TCEOCTC Bit Sync TCCentral Office EndFigure 2 - RADSL Single-Carrier System Functional Model4.3
35、Service Class DefinitionTwo classes of service are defined for RADSL transport.Class 1 service is defined as the transport of a single channel upstream and a single channeldownstream. Relative to the PTC interface shown in the system model of Figure 2 , the data channelcontains either an ATM- or pac
36、ket-based payload. This data channel is not sensitive to system latency.Class 2 service is defined as the transport of a single data channel (ATM-based or packet-based) alongwith a bit synchronous channel (e.g. an embedded 160 kb/s ISDN channel) in both the upstream anddownstream directions. This bi
37、t synchronous channel is sensitive to system latency, so any forward errorcorrection in the PTC layer is bypassed. Support of Class 2 service is optional.In both classes, an embedded operations channel (EOC) is provided.5. Single-Carrier RADSL Physical Layer DescriptionsThis chapter describes the mo
38、dems specifications for the PMD and PTC layers of Single-Carrier RADSL.5.1 System ModelThe following block diagrams further describe a RADSL system in more detail. Figure 3 depicts a Single-Carrier RADSL system from an Input/Output Stream Format. Subsequent figures provide increasinglevels of detail
39、.TECHNICAL REPORT NO. 59- 10 -5.1.1 Single-Carrier RADSL System Block Diagram and Input/Output Stream FormatCentral Office End Customer Premises EndATM orPacketTCBitSyncTCEOCTCATM orPacketTCBitSyncTCEOCTCPTC ProcessingPMD ProcessingPOTS SplitterPTC ProcessingPMD ProcessingPOTS SplitterPSTN POTSU-C U
40、-RRX-US-FRX-US-ITX-DS-ITX-DS-FRX-US-EOCTX-DS-EOCRX-DS-FRX-DS-ITX-US-ITX-US-FRX-DS-EOCTX-US-EOC= OptionalFigure 3 - Single-Carrier RADSL System Block Diagram and Input/Output Stream Format5.1.2 Functional Transmitter Reference ModelA Single-Carrier RADSL system can be based on CAP (Carrierless Phase
41、and Amplitude Modulation)and/or QAM (Quadrature Amplitude Modulation) single-carrier modulation techniques. This technicalreport describes the functionality needed to implement an ATU-R that supports both single-carriermodulations (dual-mode) and an ATU-C that supports either single-carrier modulati
42、on (single mode), asdepicted in Figure 5 . Note that it is anticipated that a Central Office will implement either CAP or QAM inits ATU-Cs. As depicted in Figure 5, there is a single interface between the Central Office and theCustomer location.Regardless of the specific single-carrier modulation te
43、chnique, a Single-Carrier RADSL transmitterimplements common functionality as depicted below in Figure 4 . A profile map of transmitter functionalityis provided in Figure 6 to describe the functions to be provided in the ATU-R. Either the Profile A CAP-Based System in Figure 7 or Profile B QAM-Based
44、 System in Figure 8 may be implemented in the ATU-C.5.1.2.1 CommonThe reference model below describes the functions that are common to a Single-Carrier RADSLtransmitter regardless of the specific underlying single-carrier modulation technique.TECHNICAL REPORT NO. 59- 11 -ATM orPacket TCBitSyncTCEOCT
45、CPTC Sub-Layer Processing PTC Scrambling* Forward Error Correction FramingPMD Sub-Layer Processing PMD Scrambling* Coding Modulation Analog ProcessingTransmitSignal= Optional* = only one scrambling function neededFigure 4 - Functional Transmitter Reference ModelCAP CAP/QAMQAM- or -Central OfficeEqui
46、pmentCustomer PremisesEquipmentFigure 5 - Reference ModelTECHNICAL REPORT NO. 59- 12 -5.1.2.2 Profile Map of Transmitter Functionality5.4.1HandshakeTC Functions Mapping OAM (Cell Delineation)PTC Functions EOCTransportScrambling PerformanceMonitoring Surveillance FEC FramingPMD Functions Scrambling C
47、oding Line CodeModulation AnalogProocessingBlock Diagram Tool to Develop Profiles5.4.2Startup Trained Startup5.4.2.1 Blind Startup 5.4.2.25.3TC5.2PMD5.3.2ATM/Packet TC Mapping Frame Based Mapping 5.3.2.1 Direct Cell Mapping 5.3.2.2 Direct Packet Mapping 5.3.3.35.3.3Bit Synchronous TC5.3.4EOC TC Fram
48、e TC 5.3.4.1 Direct Cell TC 5.3.4.2 Direct Packet TC 5.3.4.35.3.1PTC5.3.1.1PTC Scrambling Self-Synchronizing5.3.1.1.1 Bypass 5.3.1.1.25.3.1.4Framing Bit Synchronous Framing 5.3.1.4.1 Codeword Based 5.3.1.4.25.3.1.2Reed Solomon T=2 5.3.1.2.1 T=8 5.3.1.2.25.3.1.3Interleaving Implied 5.3.1.3.1 Convolut
49、ional5.3.1.3.2PMD Scrambling Frame Locked 5.2.1.1 Bypass 5.2.1.25.2.2Coding5.2.2.1Constellation Encoder 2D8S Trellis Code 5.2.2.1.1 Differential/Gray 5.2.2.2.25.2.2.2ThomlisonPrecoder5.2.3Modulation5.2.3.1 Block Diagram5.2.3.2 Symbol Rates5.2.3.3 TransmitterSpectrum5.2.3.4 PSD Mask &Xmit Signal Power5.2.4AnalogProcessor5.2.15.4Initialization 5.2.3.4Figure 6 - Block Diagram Tool to Develop Profiles5.1.2.3 ProfilesThis section depicts two profiles i.e., “highlighted” examp
