1、INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU SERIES I: INTEGRATED SERVICES DIGITAL NETWORK ISDN user-network interfaces - Layer I Recommendations 1.432.4 (02/99) B-ISDN user-network interface - Physical layer specification: 51 840 kbitls operation ITU-T
2、 Recommendation 1.432.4 (Previously CCIlT Recommendation) ITU-T I-SERIES RECOMMENDATIONS INTEGRATED SERVICES DIGITAL NETWORK GENERAL STRUCTURE Terminology Description of ISDNs General modelling methods Telecommunication network and service attributes General description of asynchronous transfer mode
3、 Scope General aspects of services in ISDN Common aspects of services in the ISDN Bearer services supported by an ISDN Teleservices supported by an ISDN Supplementary services in ISDN Network functional principles Reference models Numbering, addressing and routing Connection types Performance object
4、ives Protocol layer requirements General network requirements and functions Application of I-series Recommendations to ISDN user-network interfaces SERVICE CAPABI LIT1 ES OVERALL NETWORK ASPECTS AND FUNCTIONS ISDN USER-NETWORK INTERFACES I. 1 10-1.119 I. 120-1.129 I. I 30-1.1 39 I. 140-1.149 I. 1 50
5、-1.1 99 I .200-1.209 1.210-1.219 I .220-1.229 1.230-1.239 I .240-1.249 I .250-1.299 1.310-1.319 1.320-1.329 I. 3304.339 I .340-1.349 I. 3504.359 I. 3604.369 I. 3704.399 1.420-1.429 II Layer I Recommendations 1.430-1.439 Layer 2 Recommendations Layer 3 Recommendations Multiplexing, rate adaption and
6、support of existing interfaces Aspects of ISDN affecting terminal requirements INTERNETWORK INTERFACES MAINTENANCE PRINCIPLES B-ISDN EQUIPMENT ASPECTS ATM equipment Transport functions Management of ATM equipment I .440-1.449 1.450-1.459 I .460-1.469 1.470-1.499 1.500-1.599 I .600-1.699 I .730-1.739
7、 I. 7404.749 1.750-1.799 For further details, please refer to ITU-T List of Recommendations. ITU-T RECOMMENDATION 1.432.4 B-ISDN USER-NETWORK INTERFACE - PHYSICAL LAYER SPECIFICATION: 51 840 kbit/s OPERATION Summary This Recommendation covers Physical Layer characteristics for transporting Asynchron
8、ous Transfer Mode (ATM) cells at a nominal bit rate of 51 840 kbit/s over Category 3 Unshielded Twisted Pair (UTP) cabling at the S, reference point of the B-ISDN User Network Interface (UNI). The maximum distance is approximately 100 m. This specification may be used to take advantage of existing b
9、uilding wiring. Functionality is presented in terms of Physical Media Dependent (PMD) and Transmission Convergence (TC) sublayers, and both Synchronous Digital Hierarchy (SDH)-based and cell-based formats are included. This Recommendation is part of the 1.432-series Recommendations, and includes ref
10、erences to Recommendation 1.432.1 on general characteristics, and Recommendation 1.432.2 on Transmission Convergence sublayer aspects. Source ITU-T Recommendation 1.432.4 was prepared by ITU-T Study Group 13 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 15* of Februar
11、y 1999. Keywords Asynchronous Transfer Mode (ATM), Broadband Integrated Services Digital Network (B-ISDN), User Network Interface (UNI). Recommendation 1.432.4 (02/99) 1 STDOITU-T RECMN 1-432.4-ENGL 3999 48b2593 Ob57338 Lb3 FOREWORD ITU (International Telecommunication Union) is the United Nations S
12、pecialized Agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommuni
13、cations on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. The approval of Recommendations by the Members of the I
14、TU-T is covered by the procedure laid down in WTSC Resolution No. 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with IS0 and IEC. NOTE In this Recommendation the term recognized operating agency (ROA) includ
15、es any individual, company, corporation or governmental organization that operates a public correspondence service. The terms Administration, ROA and public correspondence are defined in the Constitution of the ITU (Geneva, 1992). INTELLECTAL PROPERTY RIGHTS The ITU draws attention to the possibilit
16、y that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Re
17、commendation development process. As of the date of approval of this Recommendation, the ITU had received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest informat
18、ion and are therefore strongly urged to consult the TSB patent database. o ITU 1999 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU.
19、Recommendation 1.432.4 (02/99) 11 STD-ITU-T RECMN 1-432-4-EMGL L999 48b259L Ob573Jt9 OTB CONTENTS Page 1 2 3 4 4.1 4.2 5 6 6.1 7 7.1 7.2 7.3 7.4 8 Scope Background . References Definitions and abbreviations . Definitions Abbreviations . Reference configuration . Characteristics of the Physical Mediu
20、m Dependent (PMD) sublayer PMD characteristics at S, for 51 840 kbit/s . 6.1.1 6.1.2 6.1.3 6.1.4 6.1.5 6.1.6 6.1.7 6.1.8 6.1.9 Bit rates . Bit rate symmetry Bit Error Ratio (BER) . Timing . Medium characteristics . Transmitter functionality . PMD ScramblerDescrambler . Receiver characteristics . Con
21、nectors for Category 3 UTP cabling . Functions provided by the Transmission Convergence (TC) sublayer Transfer capability Transport-specific TC functions . 7.2.1 SDH-based . 7.2.2 Cell-based ATM specific TC functions OAM procedures 7.4.1 SDH-based OAM 7.4.2 Cell-based OAM . Power feeding i Recommend
22、ation 1.432.4 (02/99) 1 1 3 3 3 3 3 3 3 4 4 8 8 9 9 9 10 10 11 12 12 12 12 14 . 111 Recommendation 1.432.4 B-ISDN USER-NETWORK INTERFACE - PHYSICAL LAYER SPECIFICATION: 51 840 kbit/s OPERATION (Geneva, 1999) 1 Scope This Recommendation covers Physical Layer characteristics for transporting Asynchron
23、ous Transfer Mode (ATM) cells at a nominal bit rate of 51 840 kbit/s over Category 3 Unshielded Twisted Pair (UTP) cabling at the S, reference point of the B-ISDN User Network Interface (UNI). The maximum distance is approximately 100 m. This specification may be used to take advantage of existing b
24、uilding wiring. Functionality is presented in terms of Physical Media Dependent (PMD) and Transmission Convergence (TC) sublayers, and both Synchronous Digital Hierarchy (SDH)-based and cell-based formats are included. 2 Background This Recommendation was previously contained in Recommendation 1.432
25、 (as published in March 1993) along with characteristics now published as Recommendation 1.432.1 i on general characteristics that contain characteristics which are relevant to all B-ISDN transmission systems at the UNI. This Recommendation contains only those characteristics that are specific to tr
26、ansmission systems operating at 51 840 kbit/s. Information on other bit rates can be found in other Recommendations of the 1.432-series. 3 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recom
27、mendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other re
28、ferences listed below. A list of the currently valid ITU-T Recommendations is regularly published. ITU-T Recommendation 1.432.1 (1 999), B-ISDN user-network interface - Physical layer speclfcation: General characteristics. ISO/IEC 1 1801 : 1995, Information technology - Generic cabling for customer
29、premises. ISO/IEC 8877: 1992, Information technology - Telecommunications and information exchange between systems - Interface connector and contact assignments for ISDN Basic Access Interface located at reference points S and T. ITU-T Recommendation 1.432.2 (1 999), B-ISDN user-network interface -
30、Physical layer speciJkation: I55 520 kbit/s and 622 080 kbit/s operation. ITU-T Recommendation G.707 (1 996), Network node interface for the synchronous digital hierarchy (SDH). Recommendation 1.432.4 (02/99) 1 6 7 8 ITU-T Recommendation 1.361 (1995), B-ISDNATMlayer specfication. ITU-T Recommendatio
31、n G.826 (i 996), Error performance parameters und objectives for international, constant bit rate digital paths at or above the primary rate. ITU-T Recommendation I.610 (1995), B-ISDN operation and maintenance principles and functions. 4 Definitions and abbreviations 4.1 Definitions None. 4.2 Abbrev
32、iations This Recommendation uses the following abbreviations: AIS Alm Indication Signal ATM Asynchronous Transfer Mode AU Administrative Unit BER Bit Error Ratio BIP Bit Interleaved Parity B-ISDN CEC Cell Error Control EDC Error Detection Code ISOIEC International Organization for Standardizatiorthn
33、ternational Electrotechnical LCD Loss of Cell Delineation LSB Least Significant Bit MIC Media Interface Connector NEXT Near End Crosstalk OAM Operations, Administration and Maintenance PL Physical Layer PM Physical Medium PMD Physical Medium Dependent POH Path Overhead Broadband Integrated Services
34、Digital Network Commission PPm parts per million PSN PL-OAM Sequence Number QAM Quadrature Amplitude Modulation RDI Remote Defect Indication REB Remote Errored Blocks REI Remote Error Indication 2 Recommendation 1.432.4 (02/99) STD-ITU-T RECMN 1.432.4-ENGL 1999 = 4862591 0657322 b92 = Er Et SDH Sync
35、hronous Digital Hierarchy SOH Section OverHead TC Transmission Convergence UNI User Network Interface UTP Unshielded Twisted Pair Return Loss at the receiver interface Return Loss at the transmitter interface 5 Reference configuration Refer to Recommendation 1.432.1 i. 6 Characteristics of the Physi
36、cal Medium Dependent (PMD) sublayer 6.1 PMD characteristics at S, for 51 840 kbit/s 6.1.1 Bit rates Bit rate (data rate) refers to the logical bit rate for data (expressed in kbids). Encoded line rate (symbol rate) refers to the modulation rate of the electrical signal on the media (expressed in Mba
37、ud). The nominal bit rate is 51 840 kbit/s. In the absence of a valid clock derived from the network, the transmitter at the customer side should use a free-running transmit clock that operates at the nominal bit rate with a tolerance off 1 O0 ppm. 6.1.2 Bit rate symmetry Interfaces are symmetric, i
38、.e. the bit rates are the same in both transmit and receive directions. 6.1.3 Bit Error Ratio (BER) The BER should not exceed 1 O-. Measurement of BER is normally performed out-of-service. In-service measurements based upon different parameters, e.g. Block Errors, Background Block Errors, etc., is u
39、nder study. 6.1.4 Timing 6.1.4.1 SDH-based In normal operation, timing for the transmitter is traceable to the timing received from the network clock. The tolerance under fault condition is 5 1 840 kbit/s k 1 O0 ppm. 6.1.4.2 Cell-based At the customer side at the interface S, reference point, the ce
40、ll-based Physical Layer may derive its timing from the signal received across the interface or provide it locally from a clock in the customer equipment. Recommendation 1.432.4 (02/99) 3 - STD-ITU-T RECMN 1-432-4-ENGL 1999 - 4662591 Ob57323 529 - Low Pas filter + Scrambler Encoder 6.1.5 Medium chara
41、cteristics The reference channel model as described in ISO/IEC 11 801 2 is defined to be a link consisting of 90 metres of Category 3 cable, 10 metres of Category 3 flexible cords, and four Category 3 connector pairs internal to the link. The reference channel includes the cable, patch cords, and al
42、l connection hardware. The reference channel attenuation and Near End Crosstalk (NEXT) loss, and characteristic impedance should meet the Category 3 performance limits defined in ISOIEC 1 180 1 2. Signal out - 6.1.6 Transmitter functionality The PMD sublayer functionality is shown in Figure 1. Any i
43、mplementation that produces the same functional behaviour for the transmitter is equally valid. The transmit function scrambles and encodes the bit stream received from the Transmission Convergence sublayer into an equivalent Quadrature Amplitude Modulation (QAM) encoded symbol and then into a modul
44、ated signal for presentation to the transmission medium. As shown in Figure 1, the symbol stream from the encoder is divided into two paths, a, and b, where n designates the n symbol period. The two symbol streams are sent to passband in-phase and quadrature shaping filters, respectively. The output
45、 of the in-phase filter and the negative of the output of the quadrature filter are summed into a single signal, the result passed through a low-pass filter, and then transmitted onto the twisted pair cable. Data in Figure 14.432.4 - Functional block diagram of digital 16-QAM transmitter 6.1.6.1 Sym
46、bol encoding The encoding used is a 16-QAM code with a symbol rate of 12.96 Mbaud. For 16-QAM, the encoder maps data four bits at a time into a symbol as shown in Figure 2. Bits are mapped from the PMD scrambler into the four-bit symbol. The first bit out of the PMD scrambler into a given symbol is
47、b,. _, Increasing time Symbol n + 1 a quadrant . Y T1307830-96 I Symbol n Figure 24.432.4 - Bit-to-symbol mapping for 16-QAM 4 Recommendation 1.432.4 (02/99) For 1 6-QAM, the signal constellation is as shown in Figure 3. Each incoming group of 4 bits is Gray encoded into a 16-QAM symbol. The relativ
48、e levels of the amplitude of the symbols in each dimension are proportional to the four different levels, fl and +3. Bits b,b, (circled in Figure 3) designate the quadrant. Bits b3b4 designate the point being used within the quadrant. For example, an incoming bit stream 1 O01 O 1 1 O would translate
49、 into two symbols: (a, = +I, bn = -3) and (a,+ 1 = -3, b, 1 = +i). -l O O O0 10 O -3 O O o1 11 a 10 O0 o a 11 o1 T1307840-96 Figure 3h.432.4 - 16-QAM signal constellation 6.1.6.2 The impulse response of the in-phase and quadrature filters shown in the block diagram of Figure 1 is described as follows. Let Impulse response for the transmit filters 27rt 4 COST 1 . 1 - (;) 1 T for t # 2- 4 T for t = f- 4 be a square-root raised-cosine pulse with 100% excess bandwidth. The in-phase filter impulse response is defined as: f(t) = g(t) .cos(?) Recommen
copyright@ 2008-2019 麦多课文库（www.mydoc123.com）网站版权所有
备案/许可证编号：苏ICP备17064731号-1