Very-high-speed Digital Subscriber Lines

Transcription

1 VDS SR: R5 09/4/98 Very-high-speed Digital Subscriber ines System Requirements (TE.4/98-043R5) Draft Technical Document - Revision 6 ANSI TE.4 ANSI American National Standards Institute Secretariat, Alliance for Telecommunications Industry Solutions

2 VDS SR: R5 09/4/98 FOREWORD: SCOPE AND PURPOSE: SCOPE PURPOSE REFERENCES DEFINITIONS AND ABBREVIATIONS REFERENCE CONFIGURATION AND DESCRIPTION THE VDS REFERENCE MODE (A) VDS Transmission Units (A) Network Termination (A) Service Splitters (A) Access Termination Point Network Interface Device (NID) (A) Service Module (A) VTU-O Reference Diagram in Detail (A) U Reference Points (A) VTU-R Reference Model in detail (A) VTU-O and VTU-R Data FlowsO/R Elemental/Information Flows Synchronization flow ink Control Flow ink Performance and Path Characterization Flow VDS TPS-TC performance information flow Modem Functions... 4 OAM Support... 4 Forward Error Control... 4 Multiplexing/Demultiplexing... 4 Modulation and Demodulation DISTRIBUTION-AREA TOPOOGY & ENVIRONMENTA REQUIREMENTS (A) Node Topology (A) VTU-O and VTU-R physical environment (A) temperature requirement altitude requirement transportation and storage requirements temperature limit explanation SERVICE/SPECTRA COMPATIBIITY REQUIREMENTS OF THE DISTRIBUTION AREA (A) Same twisted-pair (A) POTS compatibility requirements (A) ISDN compatibility requirements (A) In-premises service(s) compatibility requirements (A) Other twisted pair (A) Electromagnetic Compatibility with radio signals (A) Susceptibility to radio-frequency interference (A) REMOTE POWERING REPEATERED OPERATION DATA RATES, INTERWORKING, AND SERVICE REQUIREMENTS DATA RATES AND PAYOADS VERSUS RANGE EVAUATION (A) Transport Rates Requirements PERFORMANCE MEASURES (US)(A) INTERCONNECTION, "V", γ-o, AND CUSTOMER INTERFACES, "T γ-r (A) ACTIVATION AND POWER CONTRO (A, EXCEPT WHERE MARKED US) Power Control (A)... 0

3 VDS SR: R5 3 09/4/ Microinterruptions (PA) TRANSMISSION AND IMPAIRMENTS VDS OOPS (A) Effect of Bridged Taps VDS NOISES Crosstalk Noise (A) ISDN NEXT AND FEXT (A) HDS NEXT AND FEXT (A) ADS NEXT and FEXT (A) Upstream ADS (A) Downstream ADS (A) VDS NEXT or FEXT Radio Noise (A) General Requirements: (A) Test Requirements (A) AM Radio Noise Table: (A) Amateur Radio Noise: (A) Impulse Noise (US) Background Noise evel (A) Noise Masks A & B VDS INE-INTERFACE CHARACTERIZATION (A) Spectral Mask (A) POTS/ISDN band (0 to 0 khz) ADS band (0 khz to.04 MHz): A-ON and A-OFF PSD enhancement ( VDS Efficient ): V-ON and V-OFF RF Emissions notching: N-ON and N-OFF Above 30 MHz Termination Impedance (A) Return oss (A) Balance (A) ine Multiplexing (A) MODEM SIZING (A) Complexity (A) Power Consumption (A) TESTING METHODS (A) Method of Performance Measurement TIP-RING REVERSA OAM&P (A) VDS INE-REATED PRIMITIVES ATM DATA-PATH REATED PRIMITIVES OTHER VDS INDICATORS, PARAMETERS AND SIGNAS Other Near-end Pimitives Other Far-end Primitives Failure count parameters VDS line related near-end failures VDS ine related far-end failures VDS ATM REATED FAIURES Near-End ATM Related Failures Far-end ATM Related Failures VDS INE REATED PERFORMANCE PARAMETERS Performance data storage Performance data reporting A. APPENDIX A - RCG CHARACTERIZATION (A) A. TRANSMISSION-INE CHARACTERIZATION... 47

4 VDS SR: R5 4 09/4/98 A.. ABCD modeling A.. Transmission-line RCG characterization A..3 Power for transmission lines... 5 A..4 Reflection Coefficients... 5 A..5 Characterization of a bridged-tap section a three-port A..6 Computation of Transfer function A..7 Relationship of transfer function and Insertion oss A. TP A.3 TP A.4 TP A.5 FP A.6 CATEGORY-5 TWISTED PAIR B. APPENDIX B PROBABIITY OF ERROR ESTIMATION... 6 B. EFFECT OF INPUT BIT SEQUENCE... 6 B. PERIOD OF INJECTED GAUSSIAN NOISE... 6 B.3 6 DB MARGIN AND IMPORTANCE SAMPING C. APPENDIX C - POTS AND ISDN SPITTERS C. TEE TO INE DC characteristics: Insertion oss: Return oss Balance C. DS TO INE Attenutation Distortion Return oss C.3 TEE TO DS D. APPENDIX D IST OF OPERATIONA PRIMITIVES D. VDS INE-REATED PRIMITIVES D.. VDS line-related near-end primitives D.. VDS line related far-end primitives D. ATM DATA PATH REATED PRIMITIVES D.. ATM data path related near-end primitives D.. ATM payload related far-end anomalies... 69

5 VDS SR: R5 5 09/4/98 Foreword: Very-high-speed Digital Subscriber ines (VDS) permits the transmission of asymmetric and symmetric data rates as high as 5 Mbps on twisted pairs, substantially in excess of the speeds of previous DS services. This document details transmission-technique-independent system requirements for the development of a VDS standard document. Questions concerning the state of this document should be referred to the Chairman of ANSI TE.4 Mr. Thomas Starr Ameritech Services, 3C5 000 W. Ameritech Dr. Ph: Hoffman Estates, I Fax: This draft document was prepared by the Editor: Prof. John M. Cioffi Information Systems aboratory Stanford University, Ph: Stanford, CA Fax:

6 VDS SR: R5 6 09/4/98. Scope and Purpose:. Scope This system requirements document specifies characteristics that are intended to assist the development of a Very-high-speed Digital Subscriber ine (VDS) standard under the VDS standards project in ANSI TE.4.. Purpose This document will summarize requirements in the areas of:. Reference Configurations and Distribution Area Description,. Data Rates, Interworking, and Service Requirements, and 3. Transmission and Impairments, in an effort to facilitate development of a metallic interface specification for VDS transceivers.. References [] TE.4/95-4R4, "Standards project for network interfaces associated with twisted-pair transmission systems capable of operating at speeds in excess of 0 Mbps," G. Tennyson, (Bell South), August 995, Silver Creek, CO. [] Report, to be issued in 998, (currently TM6 v.0.0.7, 998-), Access transmission systems on metallic access cables: Very high-speed Digital Subscriber ine (VDS): Part : Functional requirements. [3] ANSI T , Asymmetric Digital Subscriber ine (ADS) Metallic Interface. See also ANSI TE.4/98-007R4, Issue- ADS Draft Standard. [4] ANSI T.60-99, Integrated Services Digital Network (ISDN) - Basic Access Interface for Use on Metallic oops for Application on the Network Side of the NT (ayer Specification). [5] ANSI T , Integrated Services Digital Network (ISDN) - Basic Access Interface for S and T Reference Points (ayer Specification). [6] ANSI T , Carrier-to-Customer Installation -- DS Metallic Interface. [7] Bellcore TR-NWT (September 993). Network Equipment-Building System (NEBS) Generic Equipment Requirements, Issue 5. [8] Bellcore TR-NWT (November 99) Transport Systems Generic Requirements (TSGR) Common Requirements, Issue 4. [9] Bellcore TR-NWT Electromagnetic Compatibility and Electrical Safety Generic Criteria for Network Telecommunications Equipment, Issue, October 99. [0] FCC Rules and Regulations, Part 5, Subpart J. [] IIT Reference Data for Radio Engineers, 6th Edition, Howard Sams & Co., 975, Indianapolis, IN. [] ITU-T, Rec. G.7. [3] ANSI T x, Synchronous Optical Network (SONET) -- Sub STS-Interface Rates and Format Specification, see ANSI Contribution TX.5/06-00R (no dated, place provided on reference to TE.4).

7 VDS SR: R5 7 09/4/98 [4] Bellcore TR-NWT (993), Functional Requirements for Digital oop Carrier Equipment Issue. [5] Bellcore Contribution TE.4/97-96 (C. Valenti), Primary and Secondary Parameters for 6-, 4- and -AWG PIC Cables, December 997, Sacramento. [6] Zimmerman, G., On Testing Systems with Finite ength Noise Sequences, ANSI Contribution TE.4/96-049, January, 996, Irvine, CA. 3. Definitions and Abbreviations BQ ADS AM AMI ANSI ATIS ATM ATP CO CPE DPS DS DSA DS EMC EMI EOC ETSI FEC FEXT FSAN FTTC FTTN HDS ISDN I I ISDN-BRA ISDN-PRA kbps T Mbps NEXT NT NI NID NT NTR OAMP ONU PIC PMD POTS Baseband linecode for ISDN-BA and HDS Asymmetric Digital Subscriber ines Amplitude Modulation Alternate Mark Inversion (used for T transmission with binary 8 zero sub.) American National Standards Institute Alliance for Telecommunication Industry Solutions Asynchronous Transfer Mode Access Termination Point Central Office Customer Premises Equipment Dynamic Power Saving Downstream Distribution Service Area Digital Subcriber ine Electro-Magnetic Compatibility Electro-Magnetic Interference Embedded Operations Channel European Telecommunication Standards Institute Forward Error Correction Far-end Crosstalk Full Service Access Network Fiber to the Curb/Cabinet Fiber-to-the-node High-bit-rate Digital Subscriber ines Integrated Digital Services Network Interleave Insertion oss ISDN - Basic Rate Access ISDN Primary Rate Access kilo-bits per second ine Termination Mega-bits per second Near-end Crosstalk Network Termination Non-interleave Network Interface Device Network Termination Network Timing Reference Operations, Administration, Maintenance, & Provisioning Optical Network Unit Polyolefin Insulated Cable Physical Medium Dependent Plain Old Telephone Service

8 VDS SR: R5 8 09/4/98 PSD PSTN PVC QoS RF RFI SM SNR SONET SSB SSB-SC TBD TC TE TPS TPS-TC US UTP VDS VTU-O VTU-R xds Power Spectral Density Public Switched Telephone Network PolyVinal Chloride cable Quality of Service Radio Frequency Radio-Frequency Interference Service Module Signal-to-Noise Ratio Synchronous Optical Network Single Side Band SSB - suppressed carrier to be determined Transmission Convergence (layer) terminal equipment Transport Protocol Specific Transport Protocol Specific-Transmission Convergence Upstream unshielded twisted pair Very-high-bit-rate Digital Subscriber ines VDS Transmission Unit - at the Optical network interface VDS Transmission Unit Remote Generic term refering to all DSs, ISDN, HDS, ADS, VDS, Ed: This list is not complete, contributions are encouraged. Wherever possible, every attempt will be made in this system requirements document to use metric-system measures, or at least to provide metric equivalents. The System International (metric system) is officially recognized by North American governments. 4. Reference Configuration and Description This section describes the overall physical environment in which VDS can be used. This section divides into 3 subsections on the VDS reference model, distribution-area topology requirements, and spectral/service compatibility requirements. 4. The VDS Reference Model (A) The VDS reference models appear in Figure (a) and Figure (b). Four configurations indicate the situations under consideration. There are 8 interfaces for specification. The vertical lines indicate the 8 interfaces. Figure (b) illustrates the generic interfaces for the copper access section. The γo interface is between the application and the Transport Protocol Specific (TPS) processing at the service-provider end of the line. The TPS-TC (transmission convergence) processing is outside the scope of this document. The TPS-TC interface to the Physical Media Specific (PMS) TPS is the α interface at the service provider side. The α interface is logical and application independent (and sometimes called HAPI for hypothetical application independent interface). The α interface has data flows given in Section The γr interface is between the application and the TPS-TC processing at the customer end of the line. The application implementation is called a service module (SM) at the customer side of the line. This TPS- TC (transmission conververge) processing is also outside the scope of this document. The TPS-TC interface to the Physical Media Specific (PMS) TPS is the β interface at the customer side of the line. 4.. VDS Transmission Units (A)

9 VDS SR: R5 9 09/4/98 The VTU-O (or T) is the VDS Transmission Unit at the ONU, which converts digital data to and from the continuous-time physical-layer VDS signals at the U - O interface. The VTU-R (or NT) is the VDS Transmission Unit at the Remote location, which converts digital data to or from the continuous-time physical layer VDS signals at the U -R interface. An NT connects to a single application implementation. The NT is not for further discussion in this document. γ-o Hypothetical applicationindependent interface (HAPI) α U -O U -O U- -R U -R Hypothetical applicationindependent interface (HAPI) β γ-r NID T VTU-R splitter SM splitter (NT) Application Specific Network Interface T T splitter splitter NID splitter NID splitter VTU-R (NT) VTU-R (NT) NT SM SM SM T splitter NID splitter VTU-R (NT/) SM SM TPS-TC NOT IN THIS DOC VTU-O PTSN or ISDN PMS-TC & PMD NID - Network Interface Device Protection and distribution cable termination POTS or ISDN PMS-TC & PMD SM - Service Module NOT IN THIS DOC TPS-TC Figure (a) - VDS Reference Model Key: VDS specification elements TPS-TC PMC-TC Transceiver or Transport Protocol (e.g., ATM) TPS-TC Private PMS-TC Transceiver Internal Interface γ-o α δ-o S/T Physical γ-r β δ-r Transport Protocol (e.g., ATM) TPS-TC PMS-TC Private Transceiver S/T Physical or TPS-TC PMC-TC Transceiver VTU-O (T) layered model VTU-R (NT) layered model Figure (b) - Generic Reference Model with Hypothetical Interfaces 4.. Network Termination (A)

10 VDS SR: R5 0 09/4/98 The NT in Figure (a) performs termination of the VDS modulation scheme, link control and maintenance functions, and provides logical β interface to the customer s equipment. The reference model does not imply specific ownership of the NT equipment by customer or network operator. The NT converts between NT signals and those of a customer-premises network Service Splitters (A) The service splitters separate VDS signals from other services, which can be either PSTN/POTS signals or ISDN signals Access Termination Point Network Interface Device (NID) (A) The ATP NID specifies the protection and distribution cable termination. A point-to-point reference model with active network termination will be given earliest consideration, but consideration of multidropping "passive-nid" internal-wiring configuration, and physical separation of the NID and splitter, will later occur. Only the active NT situation will be considered for evaluation of transmission techniques Service Module (A) The service module (SM) is an applications device that accepts the VDS bit stream and implements the application. Examples are set-top box interfaces and personal-computer interfaces.

11 VDS SR: R5 09/4/ VTU-O Reference Diagram in Detail (A) Figure illustrates the VTU-O reference model in more detail. An additional logical interface between the PMS-TC and the PMD core modem is shown as the δo interface. The γ-o interface is a logical interface that is beyond the scope of this document, and may require cell-specific processing. At the α interface, provision is made for both non-interleave ("fast") and interleave ("slow") delay paths in both directions. ink maintenance and link control functions are for further study, and appear in Section 7. Data flows are summarized in Section One or two possibly asymmetric bi-directional channels are supported. Associated with each data flow is implicit or explicit byte synchronization, which is maintained across the VDS link. The modem provides the master clock for the downstream channels, which may be expressed at bit or byte frequency as to be determined. Clock-rate adaptation is the responsibility of the application-dependent TPS-TC layer (e.g., by idle cell insertion/deletion in the case of ATM). Since these are logical interfaces, data may in fact be transferred in any format, including bits and bytes at constant rate, but may also be bursty when related to a clock signal. However, the average rate is assumed constant, and the depth of any buffering required is implementation dependent and outside the scope of this requirements document. Both the α and β interface flows are determined by OAM parameters at the VTU- O. γ-o α δ-o VTU-O PMS-TC FEC-US-F U -O U -O TC cell proc. (TPS-TC) FEC-US-S FEC-DS-F PMD core modem splitter FEC-DS-S NTR EOC to PSTN ink Maintenance ink control Figure Detailed VTU-O (T) Reference Model

12 VDS SR: R5 09/4/98 High-latency channels are designated IS (for interleaved slow) and low-latency channels are designated NIF channels (for non-interleavedfast). However, The NIF channels may in fact have modest interleaving if the application definition of low latency allows. Although provision is made for dual latency paths in both directions, (i.e., at both the VTU-O and VTU-R), support for a single latency path is required. Support for dual latency paths is optional. The implementation of dual-latency is deferred to the VDS standard U Reference Points (A) PSTN/POTS signals can occupy the same physical media as the VDS signal through the use of the service splitters. Consequently the U reference point refers to copper-pair media carrying composite signals, while the U reference point specifies the VDS modem ports VTU-R Reference Model in detail (A) U -R U -R δ-r β γ-r FEC US (F) NID splitter PMD core modem FEC US (S) FEC DS (F) FEC DS (S) Application Specific TPS-TC premises wiring link control link maintenance EOC NTR to phone Figure 3 Detailed VTU-R reference model. Figure 3 illustrates the VTU-R reference model. An additional logical interface between the PMS-TC and the PMD core modem is shown as the δr interface. The γ-r interface is a logical interface that is beyond the scope of this document, and may require cell-specific processing. Similar to the α interface, at the β interface provisions both non-interleave ("fast") and interleave ("slow") delay paths in both directions. ink maintenance and link control functions are for further study, and appear in Section 7. Data flows are summarized in Section The β interface supports one or two possibly asymmetric bi-directional channels, again corresponding to the α interface. Associated with each data flow is implicit or explicit byte synchronization, which is maintained across the VDS link. The modem provides the master clock for the upstream channels, which may be expressed at bit or byte frequency as to be determined. Clock-rate adaptation is the responsibility of the application-dependent TPS-TC layer (e.g., by idle cell insertion/deletion in the case of ATM). Since these are logical interfaces, data may in fact be transferred in any format, including bits and bytes at constant rate, but may also be bursty when related to a clock signal. However, the average rate is assumed constant, and the depth of any buffering required is implementation dependent and outside the scope of this requirements report. Both the α and β interface flows are determined by OAM parameters at the VTU-O.

13 VDS SR: R5 3 09/4/98 Although provision is made for dual latency paths in both directions, (i.e., at both the VTU-O and VTU-R), support for a single latency path is required. Support for dual latency paths is optional. The implementation of dual-latency is deferred to the VDS standard VTU-O and VTU-R Data FlowsO/R Elemental/Information Flows The data flows for both the VTU-O and VTU-R appear in Table. flow from the TPS-TC to the α or β interface. An arrow pointing to the right denotes Table VDS Data flows for α and β interfaces Data Flow Signal size (bits) data Downstream low-latency bit sync (NI) (F) channel byte sync data Downstream high-latency bit sync (I) (S) channel byte sync data Upstream low-latency bit sync (NI) (F) channel byte sync data Upstream high-latency bit sync (I) (S)channel byte sync Synchronization flow Synchronization flow provides the means through which synchronization between the PMD level and the TC level can occur. Synchronization flow includes: Data (bit and byte synchronization as indicated in Table : Performance and Path Characterization Primitives; Control and Performance Parameters (asynchronous); Network Timing Reference. All flows are based on a fixed timing reference except for the Control and Performance parameter passing, which is based on a message transfer protocol ink Control Flow The ink Control flow comprises all the relevant control primitives and parameters for the VDS link, as detailed in Section ink Performance and Path Characterization Flow The ink Performance and Path Chracterization flow comprises all the relevant control primitives and parameters for the VDS link, as detailed in Section VDS TPS-TC performance information flow

14 VDS SR: R5 4 09/4/98 The application independent part shall provide means for transporting indication of remote anomalies detected in the TPS-TC (such as loss of cell delineation in the case of ATM), not relying on the correct operation of the remote TPS-TC sub-layer Modem Functions The following functions should be defined in the VDS standards document: OAM Support Detection of non-correctable block errors Detection of correctable block errors Monitoring synchronization status Monitoring received signal power Forward Error Control FEC check-byte generation and error correction Interleaving Multiplexing/Demultiplexing PMD line-rate synchronization PMD frame synchronization Payload byte synchronization (compatibility with ADS is desirable) High latency and low latency data multiplexing FEC check bytes Modulation and Demodulation Modem Digital Signal Processing ADC-DAC Anti-alias filtering Transmit power control 4. Distribution-area topology & environmental requirements (A) 4.. Node Topology (A) The VDS distribution-area node should service up to 00 customers on twisted-pairs that connect the node with customer locations. Individual nodes feeding a single cable may have as many as 00 potentially crosstalking twisted pairs in the same cable, as further discussed, and subject to the limitations, in Sections 6. and 6.. Specific test loops appear in Section 6.. Vertical drop/rise segments at either the customer end or the ONU end will be specifically considered within the node, as in the test loops of Section 6.. Services on twisted-pairs within the distribution area can include VDS, POTS, ISDN, HDS, and ADS. Both buried and aerial sections of twisted pair can occur with RCG parameters as listed in Appendix B. The node has a logical V-interface presumably to an optical transmission connection with the service provider's network. 4.. VTU-O and VTU-R physical environment (A) The VTU-O and VTU-R should operate in an outdoor environment as follows ([4]): 4... temperature requirement A VDS system should meet all functional requirements and criteria in Section 0.. of [4] altitude requirement A VDS system should meet all functional requirements and criteria in Section 4..3 of [7].

15 VDS SR: R5 5 09/4/ transportation and storage requirements A VDS system should meet the transportation and storage criteria, R4-3, R4-4 and R4-5 in Section 4.. of [7] temperature limit explanation Generally, the lower bounding temperature is -40 o C. No solar load is assumed in this case, and no internal system heat is assumed present. This situation corresponds to activating a new installation on a very cold day. The upper bound on ambient temperature is +5 o C. Maximum solar load is assumed on the system enclosure, which will raise the internal ambient temperature by an estimated 8 o C. An additional 5 o C is budgeted for local heating caused by power dissipation within the system. Thus, compliance with the upper temperature limit can be shown by testing a fully configured system in a chamber with no solar load and an ambient temperature of +70 o C, or else a partially configured system in a chamber with no solar load and an ambient temperature of +85 o C. 4.3 Service/spectral compatibility requirements of the distribution area (A) 4.3. Same twisted-pair (A) The VDS physical layer is independent of applications. Work on ATM transport specification, including transconvergence layer, should be compatible with this independent VDS physical layer. VDS service should noninvasively coexist with the following services on the same twisted-pair between node and remote modem: POTS ISDN BRA (T.60) in-premises services Note that ISDN and POTS can not be simultaneously used POTS compatibility requirements (A) POTS should be separated from VDS by a splitter circuit that is possible to be implemented passively that prevents failure of the VDS system from affecting the POTS service. oss of VDS service should not obstruct the operation of POTS. See the informative Appendix C ISDN compatibility requirements (A) ISDN should be separated from VDS by a splitter circuit that is possible to be implemented passively that prevents failure of the VDS system from affecting the ISDN service. ocal power failure should not obstruct the operation of ISDN. See the informative Appendix C In-premises service(s) compatibility requirements (A) VDS compatibility with in-premises services, that is compatibility with other electronic signals that may be introduced by non-vds/isdn/pots customer equipment, is deferred to the VDS standard document as it is line-code dependent Other twisted pair (A) VDS service should be compatible with other VDS, ISDN, HDS, ADS and/or POTS services on twisted pair in other lines in the same binder. Co-existence of asymmetric and symmetric VDS systems

16 VDS SR: R5 6 09/4/98 in the same multi-pair cable should be possible, possibly with performance penalty. No special arrangements should be required for pair selection Electromagnetic Compatibility with radio signals (A) VDS should be fully compliant with FCC part 5 with cable considerations for measurement Susceptibility to radio-frequency interference (A) VDS should operate at bit error rate lower than e-7 with 6 db of margin in the presence of electromagnetic interference from AM radio, any amateur radio operators. 4.4 Remote Powering VDS need not be remote powered. 4.5 Repeatered Operation Repeatered operation is not a requirement for VDS. 5. Data Rates, Interworking, and Service Requirements This section describes data rates and requirements based on anticipated applications of VDS. 5. Data Rates and Payloads versus range evaluation (A) VDS should consider both asymmetric and symmetric transmission between the node and customer. The payload data rate combinations to be given primary evaluation are: Name of Service Type Table VDS Payload Bit Rates Downstream Data Rate (Mbps) Upstream Data Rate (Mbps) Range kft. (km) Asymmetric Short (.3) 34 or Medium () 9.3 ong (.5) or.8 6 () Symmetric Short 6 6 (.3) 9 9 Medium () ong (.5) The data rates in the above table for system performance evaluation should be considered for purposes requiring greater bit-rate granularity as 5 Mbps = 5. Mbps, 6 Mbps = 5.6 Mbps, 9 Mbps = 9. Mbps, 3 Mbps =.8 Mbps, and 6.5 Mbps = 6.4 Mbps. These data rates are primarily intended for ATM transport and are for range-evaluation purposes only.

17 VDS SR: R5 7 09/4/98 The payload data rate of the EOC should not be less than 4 kbps and not more than 64 kbps. The EOC should be able to operate in a clear-channel mode that is duplex transparent bit or byte transmission. 5.. Transport Rates Requirements The exact transport data rates should be specified in the VDS standard. The VDS standard should define line rates so as to allow interoperability between different vendor s equipment. 5. Performance measures (US)(A) The probability of error should be lower than Pe=0-7 measured according to measurement methods described in Section 6.5 with 6 db of margin on the loops and in the presence of the noises specified in Table 6.5. The measurement period shall be at least 30 minutes and the amateur radio interferer shall visit each amateur band at least twice (at different frequencies within the band) during the test period. A long term performance test shall be performed for a period of not less than 4 hours to ensure long-term temporal stability. Errored seconds, cell loss, and cell delay are deferred to the VDS standard. In the presence of multiple noises (except RFI), performance margin will be measured with all summed noises increasing by a common factor. FEC was removed from this document and instead relegated to PMD and/or TC standards documents. The maximum "fast" path delay approximately.00 ms and maximum interleave-path delay 0 0 ms milliseconds, with 0 0 ms delay optional. The latency is measured between the hypothetical (logical) interfaces in the system reference diagrams of Figure and Figure 3, currently called the α and β interfaces. Dual latency is optional, but single latency should have programmed delay in ms increments. Implementations shall provide the means to verify delay between the α and β interfaces for the purposes of laboratory design qualification testing, although this may require additional external hardware and software not provided for normal use. The latency measurement method may be extended to the TPS-TC layer as well as to the γ interfaces, where the elements may for instance be ATM cells. Timing and synchronization requirements should be specified in the standards document because they are dependent on transmission technique. Use of the 0 ms latency choice should allow correction of noise bursts up to 500 µs in length, while use of the 0 ms latency choice should allow correction of noise bursts up to 50 µs. 5.3 Interconnection, "V", γ-o, and Customer interfaces, "T γ-r (A) The V γ-o and T γ-r interfaces should be specified in the standards document, but are not further addressed in this systems requirement document. The V γ-o and T γ-r interface specifications should state any framing of data for media access control. 5.4 Activation and Power Control (A, except where marked US)

18 VDS SR: R5 8 09/4/98 Figure 4 illustrates the initialization, activation, and power-control procedure for a VTU. The connections in the diagram are meant to be self explanatory, but the ovals and rectangles shown are each described in this section. An oval indicates a state, in which the VTU may stay indefinitely while a rectangle indicates a process, from which the VTU is expected to emerge after a specified period of time given by T, T, T3, or T4. The Power-Down Process has no time out. No (Quiet) Power-off (Service Installation or change) Power-up Request Power Down Power-up Request Power-down or Power Failure Cold-Start (T=0s) No (Quiet) Normal-Start (T=5s) No (Quiet) Resume-on-Error (T3=300ms) µ-interrupt Yes Yes Yes End of Error Event T5 < s Steady-State Transmission Power loss Sync. loss > 0ms oss of Sync. (oss of Symbol)) Dynamic Power Save Hot Resume Idle Back-to-Service Request Yes Warm-Start (T4=00ms) Sync. loss Power loss No (Quiet) Figure 4 - State and Timing Diagram Activation and deactivation may be commanded by network management, or result from autonomous actions caused by transmission anomalies. Additionally, where call-state information is available, activation may be linked to broadband call-state transitions. Such linkage is not applicable to SDH applications, and is not currently supported by ATM level standards. Methods may however, be developed to enable the transmission performance advantages for VDS to be exploited by ATM applications. On first installation or on demand of the network operator, the activation of a VDS transceiver might be subject to an installation procedure under control of the network operator in order to check the spectral compatibility of the transceiver. (NOTE: such test procedure is not specified in this document.) Following

19 VDS SR: R5 9 09/4/98 a successful first installation, the activation processes shall start. Five Four activation processes shall exist. There are defined below and shown in Figure 4. Service Installation Process: The service installation process is for further study and deferred to the VDS standard. Basically, this process brings the VDS to a point ready for activation. Cold-Start Process: The Cold-Start activation process starts after power is first applied to the transceiver after intrusive maintenance or if there have been significant changes in line characteristics (e.g. due to thermal effects). Intrusive maintenance will also apply to the service level, when transmission rates, and other transmission parameters (e.g., margin, spectral masks, class of service, etc.) are altered. Cold Start may also be entered from the Normal-Start State when significant line change has occurred. The Cold Start Process should complete in less than T=0 seconds or an indication is provided by the VTU-O to the operator of the inability to start. Normal-Start Process: This Normal Start Process applies when both VTU-O (T) and VTU-R (NT) activate from the Power-Down state. Power-Down is reached when a transceiver had its AC removed on purpose via the Power-Down procedure, forced typically by the customer. Normal-start applies only if there have been little or no changes in line characteristics. This procedure applies also, when there is an accidental AC removal or failure at the customer, provided the transceiver could store all necessary data and parameters to avoid the Cold-Start. The Normal Start Process should complete within T=5 seconds, typically seconds and if not then enter to the Cold Start Process. Warm-Start Process: The Warm-Start Process applies to transceivers after reaching synchronization and Steady-State Transmission and have subsequently responded to a deactivation request, which means entry is through the Idle State. Warm-resume is the usual method of activating the VDS transmission system on receipt of a first incoming or outgoing broadband call request. Warm-Resume can only be initiated after a deactivation procedure, towards the Power-Saving state, which keeps both T and NT VDS transceivers in a power-saving sleeping mode. The Warm-Start Process should complete within T3 T4=00 ms, and if not then enter either the Normal Start Process and/or the Resume-on-Error Process if synchronization loss has occurred. Resume-on-Error Process: Resume-on-Error Process applies to transceivers that lose synchronization during transmission, e.g. due to a large impulse hit or an interruption longer than micro-interruption. This applies only if there have been no changes in line characteristics, and when the clock-frequencies recovery circuits can still predict the sample timing. The event which leads to this type of loss of synchronization, must be longer than a micro-interruption (0 ms). but with a timer T5>T3 that when exceeded causes the resume on error process to begin, related to the loss of frequency locking, that will be specified in the PMD-dependent portion of the VDS standard. The value of the T5 timer is transmissiontechnique-dependent and therefore deferred to the VDS Standards Document. The Resume-on-Error Process should complete within T3=300 milliseconds, and if not then enter the Normal Start Process. The resume-on-enter process must be entered within T5< second after detection of loss of synchronization. There are also five mandatory states and one optional state: Steady-State Transmission State: The state of Steady-State Transmission is entered through succesful completion of any of the Cold-Start, Normal-Start, Warm-Start, or Resume-on-Error Processes. This means full clock and frame synchronization have been achieved and DSP filter adaptations have been performed. Steady-StateTransmission may be exited upon power-loss or by entering the Idle State. Microinterruptions may occur during Steady-State Transmission as long as rapid recovery of duration much less than the Warm-Start Process. Idle State: This is a state where the VDS transceiver may be in save ONU power and reduce unwanted RF emissions. Included in this process is the confirmation towards UNI and the network side that the VDS transmission is terminated. The Deactivation assumes the termination of all broadband traffic. The Idle State is exited when a call request occurs through the Warm-Resume Process, when synchronization loss is detected, or when power loss is detected.

20 VDS SR: R5 0 09/4/98 Power-Down State: The full removal of power at the NT or T, or the state at the T when the Power- Saving deactivated state can not be used and VDS transmission must be halted, e.g., for maintenance (hardware and/or software). Power-Off State: Equipment state prior to installation or first powering. oss-of-synchronization State: This state is entered from Steady-State Transmission when synchronization loss is detected between the two VDS transceivers, which can occur any time after 0 ms of synchronization loss have been detected.. The transceivers will attempt to resynchronize and use previous line-condition parameters through the Resume-on-Error Process. Dynamic Power Savings State: The optional Dynamic Power Savings State is intended to reduce the overall power consumption of the VTU-O transceiver, and to reduce the crosstalk level and RFI radiation of the VDS system. It could be used when ATM or some other application links are active, but are not consuming the full bandwidth of the VDS transmission. It alternates with the Steady-State Transmission State. No loss of application data should be tolerated when the VDS transceiver moves between Steady State and Dynamic Power Savings states. This state implies the Hot Resume. Comment on Delay to service start-up : The time from when Activation is requested or power is applied until the broadband dial tone is issued towards the UNI. The VDS system must have achieved Steady State transmission before the broadband dial tone (or equivalent) is issued Power Control (A) In order to prevent unwanted detrimental intereactions between VDS transceivers operating on the same multi-pair cable, the ability to lower the transmit power spectral desnity should be provided. The VDS transmitter should have an ability to reduce its transmit PSD whenever the required SNR margin at the corresponding receiver is exceeded significantly while transmitter operates at its maximum PSD. The adjustment is attenuation to reduce the transmit spectrum below the maximum allowed. The minimum attenuation allowed is zero i.e., if the system cannot obtain the specified SNR margin at a receiver then the corresponding transmitter will transmit at its maximum allowed PSD Microinterruptions (PA) A micro interruption is a temporary line interruption caused by external mechanical action on the copper wires constituting the transmission path, for example, at a cable splice. Splices can be hand-made wire-towire junctions, and during cable life oxidation phenomena and mechanical vibrations can induce micro interruptions at these critical points. The effect of a micro interruption on the transmission system can be a failure of the digital transmission link, together with a failure of the power feeding (if provided) for the duration of the micro interruption. The objective is that in the presence of a micro-interruption of specified maximum length, the VDS transceiver should not reset, and the system should automatically reactivate. The transceiver should not be reset by a microinterruption of duration up to 0 ms, which shall occur at an event frequency of. Hz. 6. Transmission and Impairments 6. VDS oops (A).The loops in Figure 5 characterize distribution node twisted-pairs and will be used for testing and competitive evaluations. The RCG parameters for the different types of wires used are in the Appendix.

21 VDS SR: R5 09/4/98 Table 3 summarizes the purpose of test for each of the 8 VDS loops. Table 3 enumerates short-, medium, and long-range values for a nominal length variable in VDS through VDS4. No. VDS0 VDS VDS VDS3 VDS4 VDS5 VDS6 VDS7 Table 3 VDS oops Rationale null loop (also in ETSI) range stress limit (also in ETSI), underground cable flat-wire vertical drop (also in ETSI), horizontal aerial cable on other section Reinforced-wire vertical drop (also in ETSI), horizontal aerial cable on other section bridged tap, horizontal aerial cable short loop test with bridged taps and various crosstalk (may also sometimes represent CPE wiring) medium loop test with bridged taps and various crosstalk (may also sometimes represent CPE wiring) long loop test with bridged taps and various crosstalk (may also sometimes represent CPE wiring) Table 4 Nominal engths for asymmetric VDS oops Variable Name Short Value Medium Value ong Value x (VDS) 000 ft. (304.8m) 3000 ft. (94.4m) 4500 ft. (.376 km) y (VDS) 500 ft. (457.m) 3000 ft. (94.4m) 4500 ft. (.376 km) z (VDS) 500 ft. (457.m) 3000 ft. (94.4m) 4500 ft. (.376 km) u (VDS3) 500 ft. (457.m) 3000 ft. (94.4m) 4500 ft. (.376 km) v (VDS4) 000 ft. (304.8m) 3000 ft. (94.4m) 4500 ft. (.376 km)

22 VDS SR: R5 09/4/98 VDS0 (null loop) 6.5 ft (m) TP TP ~.4mm or 6-gauge - see appendix for rlcg TP ~.5mm or 4-gauge - see appendix for rlcg TP3 ~ DW0 - see appendix for rlcg FP - flat untwisted pair - see appendix for rlcg VDS (range test for given data rate) VDS (flat wire in drop) VDS3 VDS5 (short - "The ittle Demon") 550 ft (67m) TP (underground cable 0-pair) x (ft) TP ; y (ft) TP underground cable z (ft) of TP aerial cable u (ft) of TP aerial cable (reinforced tp in drop - "Kevin's Castle") VDS4 (bridge tap) v (ft) of TP aerial cable (underground,5- pair) 300 ft (9.4m) TP 50 ft (45.7m) TP 00 ft (30.4m) TP 50 ft (76.m) TP (overhead aerial) 50ft (76.m) FP (vertical) 50ft (76.m) TP3 (vertical) 50 ft (45.7m) TP 90 o 50 ft (5.m) TP horizontal 50 ft (5.m) TP3 horizontal VDS6 (medium) 650ft (503m) TP (underground cable 00-pair) 650ft (98m) TP (underground cable 00-pair) VDS5 VDS7 (long) 650ft (503m) TP (dist'n cable 00-pair) 300ft (70m) TP (underground cable 00-pair) VDS5 Figure 5 - VDS test loops.

23 VDS SR: R5 3 09/4/98 Figure 6 Insertion loss of Test oops in Figure 5. (length labels are approximate see Table 4 for exact values)

24 VDS SR: R5 4 09/4/98 Figure 7 Delay of VDS test loops in Figure 5. (length labels are approximate see Table 4 for exact values

25 VDS SR: R5 5 09/4/98 Figure 8 Impedance of test loops in Figure 5. (length labels are approximate see Table 4 for exact values

26 VDS SR: R5 6 09/4/ Effect of Bridged Taps Advisory Note: Bridged taps may have a very significant effect on reach in VDS. A bridged-tap is an open-circuited tesited pair, which is connected in parallel with a working loop. oops VDS4-VDS7 all contain bridged taps in Figure 5. At the bridging/splitting location, the signal separates into two components. The component traversing the bridged-tap line is reflected at the open circuit and recombines with the first component. At those frequencies for which the reflected component is approximately 80 degrees different in phase than the first component, the two components destrutively intefere. This destructive interference manifests itself as a notch at all such frequencies in the channel insertion-loss characteristic. These notch frequencies correspond to those for which the length of the bridged tap is one-quarter of a wavelength. More precisely, assuming d = length of the bridged tap (ft) c=speed of light, m / s v=phase velocity in the twisted pair λ = the wavelength ε r = relative dielectric constant of the loop Frequency khz MHz 00 MHz Polyethylene PVC Pulp (paper) µ ρ ==relative permittivity The wavelenth λ=v/f and velocity v = c = c ε µ ε r r r lead to an expression for the frequencies (in MHz, polyethylene) at which the bridged-tap length is an odd number of quarter wavelength(s) that is equal to f notch = m d d ( m + ) = =,,... feet For VDS, many of these frequencies are less than 30 MHz, the upper limit for transmission, leading to severe notching within the transmission band. Furthermore, long bridged taps introduce up to 3.5 db degradation in insertion loss across the enitre band. The insertion loss characteristics of VDS 4,5,6 and 7 appear in Figure 6 and illustrate the effect. meters 6. VDS Noises VDS noises should be used for testing and evaluation of VDS systems on the loops in Section 6.. Several power spectral densities appear in Figure 9. Figure 9 NEXT PSD s worst-case 49 active. 6.. Crosstalk Noise (A) Near-end crosstalk or NEXT should be a Gaussian signal with power spectral density given by

27 VDS SR: R5 7 09/4/98 PSD NEXT = PSD disturber K next.6. 5 ( N / 49) f where N is the number of crosstalkers. Far-end crosstalk or FEXT is similarly PSD FEXT = PSD disturber K fext.6 ( N / 49) d H ( f ) f where d is the length of the loop in feet. For category-5 twisted pair, which is listed in Section 8.5 of the appendix for information purposes, the 4 6 coefficient = = and the coefficient K K next changes to K next cat 5 0 = The category-5 numbers may be more = fext changes to K fext cat 5 appropriate for new buildings or intra-campus/corporate symmetric transmission ISDN NEXT AND FEXT (A) For ISDN NEXT or FEXT, PSD ISDN ( f ) = K ISDN sin πf f 0 f 0 πf f0 + f f 0 4 where f 0 = 80kHz, K ISDN = 5 9 V p R, V p =.5 Volts, and R = 35Ω HDS NEXT AND FEXT (A) For HDS NEXT or FEXT, PSD HDS ( f ) = K HDS sin πf f 0 f 0 πf f0 + f f 3db 8 where f 0 = 39kHz, f 3db = 96kHz, K HDS = 5 9 V p R, V p =.7 Volts, and R = 35Ω ADS NEXT and FEXT (A) Upstream ADS (A) Figure 0 shows the power spectral density (PSD) mask for the transmitted signal. The low frequency stop band is defined as the voice band; the high frequency stop band is defined as frequencies greater than 38 khz.

28 VDS SR: R5 8 09/4/98 PSD (dbm/hz) peak.5 db/oct 48 db/oct -90 peak peak +5 dbrn 0-4 khz -9.5 peak -50 dbm max power in any MHz sliding window above 630 khz Freq (khz) Figure 0 ADS Upstream Power mask FREQUENCY BAND (khz) EQUATION FOR INE (dbm/hz) 0 < f < , with max power in the in 0-4 khz band of +5 dbrn 4 < f < log (f/4) < f < < f < log (f/38) 307 < f < -90 < f < peak, with max power in the [f, f + MHz] window of ( log (f/) + 60) dbm 630 < f < peak, with max power in the [f, f+mhz] window of -50 dbm NOTES. All PSD measurements are in 00 ohms; the voice band aggregate power measurement is in 600 ohms.. All PSD and power measurements should be made at the U-R interface (see Error! Reference source not found.); the signals delivered to the POTS are specified in ANNEX E. 3. The breakpoint frequencies and PSD values are exact; the indicated slopes are approximate. 4. Above khz, the peak PSD should be measured with a 0 khz resolution bandwidth. 5. The power in a MHz sliding window is measured in MHz bandwidth, starting at the measurement frequency. For more information, see [3], Section Downstream ADS (A) Figure shows the power spectral density (PSD) mask for the transmitted signal. The low frequency stop band is defined as the voice band; the high frequency stop band is defined as frequencies greater than.04 MHz.

29 VDS SR: R5 9 09/4/98 PSD (dbm/hz) peak db/oct 36 db/oct -90 peak peak +5 dbrn 0-4 khz -9.5 peak -50 dbm max power in any MHz sliding window above 4545 khz Freq (khz) Figure ADS Downstream Power Mask FREQUENCY BAND (khz) EQUATION FOR INE (dbm/hz) 0 < f < , with max power in the in 0-4 khz band of +5 dbrn 4 < f < log (f/4) < f < < f < log (f/04) 3093 < f < peak, with max power in the [f, f + MHz] window of ( log (f/04) + 60) dbm 4545 < f < peak, with max power in the [f, f+mhz] window of -50 dbm NOTES. All PSD measurements are in 00 ohms; the POTS band aggregate power measurement is in 600 ohms.. All PSD and power measurements should be made at the U-C interface (see Error! Reference source not found.); the signals delivered to the PSTN are specified in ANNEX E. 3. The breakpoint frequencies and PSD values are exact; the indicated slopes are approximate. 4. Above khz, the peak PSD should be measured with a 0 khz resolution bandwidth. 5. The power in a MHz sliding window is measured in MHz bandwidth, starting at the measurement frequency. For more information, see [3], Section VDS NEXT or FEXT VDS NEXT and FEXT is transmission-technique dependent, but the VDS standard should consider VDS self-next and VDS self-fext using the same NEXT and FEXT transfer functions as all of the other DS crosstalkers earlier in this section. VDS NEXT and FEXT into other services is included in the considerations for the PSD mask specified in Section Radio Noise (A) This section is agreed except where otherwise noted General Requirements: (A)

30 VDS SR: R /4/98 The VDS system is required to meet its reach and quality of service requirements with adequate margin (6 db at e-7), considering crosstalk (see Section 6..), impulse noise (see Section 6..3), system noise and broadband environmental noise (See Section 6..4) contributions, while at the same time the loop is subject to simultaneous RFI from multiple AM broadcast stations, and an adjacent amateur radio station. It may be necessary to employ special measures where customers aerial drop wire or unshielded riser cable is very close to the nearest interfering transmitter, i.e., within 300ft of a 50 kw AM broadcast transmitter. Similarly special measures may be necessary to deal with the situation where an unshielded part of the customer s loop or riser is within 00 ft. of an amateur station s antenna. Two worst cases are mutually exclusive since it is unlikely that an amateur station will be able to operate as close as 300 ft from an AM broadcast transmitter, so when worst-case AM broadcast interference is encountered, it can be assumed that the worst-case amateur radio interference is likely to be 0 lower than worst-case, and the same argument can be applied reciprocally when the customer is close to an amateur station Test Requirements (A) Ed: This section agreed except where TBD's exist. The VDS system should meet transmission performance objectives over the reference test loops with 6 db margin while subject to any of 3 simulated RFI threats, each comprising 3 different signals. Each simulated RFI threat includes 0 simulated AM broadcast stations in the band 535 to 605 khz and one simulated Amateur Radio SSB transmission. Other sources of RFI can be considered in the VDS standard, but were omitted here for lack of contributions in the area after 8 months of requests for such. The AM broadcast sources are modeled by a fixed frequency carrier 30% AM modulated with a flat (± 3 db) Gaussian noise source band limited to 0-5 khz. The average power of the modulated signal is specified in Table 5. The simulated amateur transmission is an SSB modulated carrier that changes frequency (F3) every minutes, by at least 50 khz, and visits all amateur bands in the VDS passband during each BER test. The baseband signal is speech weighted noise (ITU-T, Rec. G.7). This is interrupted on a 5-second period with 5 sec ON AND 0 seconds OFF to simulate speech activity. The resultant baseband signal is further interrupted on a period of 00 ms with 50 ms ON and 50 ms OFF -- approximately the syllabic rate. The doubly interrupted signal is then bandlimited to 4 khz and subject to 6 db per octave pre-emphasis. (This model combines the effects of transmit path speech processing for enhanced intelligibility and the spectral balance of sibilant unvoiced sounds.) The two types of RFI noises into VDS are further specified below: 6... AM Radio Noise Table: (A) (CM = common mode ; DM = differential mode) Models and represent urban high-density areas, while Model 3 represents a suburban environment. The following differential mode levels were proposed based on measurements Table 5 Signal Strengths for AM Radio Noise into VDS. distance to AM radio transmitter DM strength (dbm) 300 ft ft ft ft -70