1、 STD.ETSI EN 300 429-ENGL 1798 m 3400855 0284863 TT2 EN 300 429 VI 2.1 (1998-04) European Standard (Telecommunications series) Digital Video Broadcasting (DVB); Framing structure, channel coding and modulation for cable systems STD-ETSI EN 300 429-ENGL 1998 3400855 02848b4 939 2 EN 300 429 V1.2.1 (1
2、 998-04) Reference REN/JTC-DVB-71 (3000ioo.PDF) Keywords DVB, digital, video, broadcasting, cable, MPEG, TV ETSI Postai address F-O6921 Sophia Antipolis Cedex - FRANCE Office address 650 Route des Lucioles - Sophia Antipolis Valbonne - FRANCE Siret No 348 623 562 00017 - NAF 742 C Association but no
3、n lucratif enregistre la Souc-Prfecture de Grasse (06) No 7803/88 Tel.: +33 4 92 94 42 O0 Fax: +33 4 93 65 47 16 internet secretariat etsi.fr http:/www. etsi .fr htp:/www.etsi.org Covvriuht Notification No part may be reproduced except as authorized by written permission. The copyright and the foreg
4、oing restriction extend to reproduction in ail media. O European Telecommunications Standards Institute 1998. Q European Broadcasting Union 1998. All rights reserved. ETSI STD-ETSI EN 300 429-ENGL 1998 W 3400855 3 0284865 875 = EN 300 429 V1.2.1 (1998-04) Contents Intellectual Property Rights 4 Fore
5、word 4 1 2 3 3.1 3.2 4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 5 6 7 7.1 7.2 7.3 8 9 Scope 5 References 5 Symbols and abbreviations 5 Symbols 5 6 Cable System conc . 6 Abbreviations . . Baseband interfacing and sync . Sync 1 inversion and randomization Reed-Solomon (RS) coder Convolutional interleaver .
6、 . . . . 8 8 . 8 Cable receiver Framing structure . 9 Channel coding . . 10 Randomization for spectrum shaping . Reed-Solomon coding . 11 Convolutional interleaving . 11 Byte to symbol mapping 12 Modulation . 13 . 10 Annex A (normative): Baseband filter characteristics . 17 Transparency of cable net
7、works. . 18 Bibliography . 19 Annex B (informative): Annex C (informative): History 20 ETSI 4 EN 300 429 Vl.2.1 (199-04) Intellectual Property Rights IPRs essential or potentially essential to the present document may have been declared to ETSI. The information pertaining to these essential iPRs, if
8、 any, is publicly available for ETSI members and non-members , and can be found in ETR 314: “Lnteliectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respect of ETSl standards“, which is available free of charge from the ETSI Secretariat. Latest updates are
9、available on the ETSI Web server (h ttp: / w ww .et si. fdipr). Pursuant to the ETSI Interim PR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee can be given as to the existence of other iPRs not referenced in ETR 314 (or the updates on http:/www.etsi.fr/i
10、pr) which are, or may be, or may become, essential to the present document, Foreword This European Standard (Telecommunications series) has been produced by the Joint Technical Committee (JTC) of the European Broadcasting Union (EBU), Comit Europen de Normalisation ELECtrotechnique (CENELEC) and the
11、 European Telecommunications Standards institute (ETSI). NOTE: The EBUETSI JTC was established in 1990 to co-ordinate the drafting of standards in the specific field of broadcasting and related fields. Since 1995 the JTC became a tripartite body by including in the Memorandum of Understanding also C
12、ENELEC, which is responsible for the standardization of radio and television receivers. The EBU is a professional association of broadcasting organizations whose work includes the co-ordination of its members activities in the technical, legal, programme-making and programme-exchange domains. The EB
13、U has active members in about 60 countries in the European broadcasting area; its headquarters is in Geneva *. * European Broadcasting Union CH-1218 GRAND SACONNEX (Geneva) Switzerland Tel: 41 22717 21 11 Fax: +41 22 717 24 81 Digital Video Broadcasting (DVB) Project Founded in September 1993, the D
14、VB Project is a market-led consortium of public and private sector organizations in the television industry. Its aim is to establish the framework for the introduction of MPEG-2 based digital television services. Now comprising over 200 organizations from more than 25 countries around the world, DVB
15、 fosters market- led systems, which meet the real needs, and economic circumstances, of the consumer electronics and the broadcast indus try. National transposition dates Date of adoption of this EN: Date of latest announcement of this EN (doa): 17 April 1998 31 July 1998 Date of latest publication
16、of new National Standard or endorsement of this EN (dople): 31 January 1999 I Date of withdrawal of any conflicting National Standard (dow): 31 January 1999 ETSI STD-ETSI EN 300 429-ENGL 1998 3400855 0284867 648 9 5 EN 300 429 V1.2.1 (1998-04) 1 Scope The present document only adds 128 and 256 QAM t
17、o the specification The present document describes the framing structure, channel coding and modulation (denoted “the System“ for the purposes of the present document) for a digital multi-programme television distribution by cable. The aim of the present document is to present a harmonized transmiss
18、ion standard for cable and satellite, based on the MPEG-2 System Layer ISO/IEC 13818-1 i, with the addition of appropriate Forward Error Conection (FEC) technique. This System can be used transparently with the modulation/channel coding system used for digital multi-programme television by satellite
19、 (see EN 300 421 3). The System is based on Quadrature Amplitude Modulation (QAM). It allows for 16, 32, 64, 128 or 256-QAM constellations. The System FEC is designed to improve Bit Error Ratio (BER) from lo4 to a range, 10-l to IO-“, ensuring “Quasi Error Free“ (QEF) operation with approximately on
20、e uncorrected error event per transmission hour. 2 References References may be made to: a) specific versions of publications (identified by date of publication, edition number, version number, etc.), in which case, subsequent revisions to the referenced document do not apply; or b) all versions up
21、to and including the identified version (identified by “up to and including“ before the version identity); or c) all versions subsequent to and including the identified version (identified by “onwards“ following the version identity); or d) publications without mention of a specific version, in whic
22、h case the latest version applies. A non-specific reference to an ETS shall also be taken to refer to later versions published as an EN with the same number. il PI ISO/IEC 13818-1: “Coding of moving pictures and associated audio“. IEEE Trans. Comm. Tech., COM-19, pp. 772-781, (October 1971) Forney,
23、G.D.: “Burst- correcting codes for the classic bursty channel“. EN 300 421: “Digital Video Broadcasting (DVB); Framing structure, channel coding and modulation for 11/12 GHz satellite services“. 31 3 Symbols and abbreviations 3.1 Symbols For the purposes of the present document, the following symbol
24、s apply: Roll-off factor Most Significant Bits at the output of the Byte to m-tuple converter Channel centre frequency Nyquist frequency RS code generator polynomial Hexadecimal Interleaving depth (bytes) In-phase, Quadrature phase components of the modulated signal Branch index Number of bytes mapp
25、ed into n symbols ETSI STD-ETSI EN 300 Y29-ENGL I1998 m 3400855 02848b 584 m 6 EN 300 429 Vi .2.1 (1 998-04) m 3.2 Power of 2m-level QAM: 4,5,6,7,8 for 16-QAM, 32-QAM, 64-QAM, 128-QAM, 256-QAM respectively Convolutional interleaver branch depth for j = 1, M = N/I Number of symbols mapped from k byte
26、s Error protected frame length bytes RS field generator polynomial In-band ripple (dB) Randomized sequence Symbol rate corresponding to the bilateral Nyquist bandwidth of the modulated signai Useful bit rate after MPEG-2 transport multiplexer Bit rate after RS outer coder Number of bits: 2,3,4,5,6 f
27、or 16-QAM, 32-QAM, 64-QAM, 128-QAM, 256-QAM respectively Number of bytes which can be corrected in RS error protected packet Symbol period Abbreviations For the purposes of the present document, the following abbreviations apply: BB BER DTVC FEC FIFO IF IRD LSB MPEG MSB MUX PDH PRBS QAM QEF RF RS SM
28、ATV TDM TV Baseband Bit Error Ratio Digital Television by Cable Forward Error Correction First In First Out Intermediate Frequency Integrated Receiver Decoder Least Significant Bit Moving Pictures Experts Group Most Significant Bit Mu1 tiplex Plesiochronous Digital Hierarchy Pseudo Random Binary Seq
29、uence Quadrature Ampli tude Modulation Quasi Error Free Radio Frequency Reed-Solomon Satellite Master Antenna Television Time Division Multiplex Television 4 Cable System concept The cable System shall be defined as the functional block of equipment performing the adaptation of the baseband TV signa
30、ls to the cable channel characteristics (see figure 1). In the cable head-end, the following TV baseband signal sources can be considered: - satellite signal(s); - contribution link(s); - local program source(s). The processes in the following subclauses shall be applied as shown in figure 1. ETSI 7
31、 EN 300 429 V1.2.1 (1998-04) . e . . e . . . . . . . . . . . . . . . . . e e . . . . e . . . . e . . . . . . . . . . . . e U c ?) U m 0 I a n m - o *w c- - O 4 I u- - t t t t . . . . . . o . . . e . . . . . . . . o . . . . . . . . . . e . . . . . . . . . . . . . e . . . . . o . . . o . m . . . . . m
32、 . . . . . . . I . . . . . . . . . . . . . . . . . . e . . . . -I -1 -4 uzlg m mu - .- t t f t t u =- ow . - TZ cm m . . . . . . o . . o . o . . . . . . . . . . . . . . . . . . Figure 1: Conceptual block diagram of elements at the cable head-end and receiving site _ STD.ETS1 EN 300 429-ENGL 1998 340
33、0855 0284870 132 8 EN 300 429 V1.2.1 (1 998-04) 4.1 Baseband interfacing and sync This unit shall adapt the data structure to the format of the signal source. The framing structure shall be in accordance with MPEG-2 transport layer including sync bytes. NOTE: Interfaces are not part of the present d
34、ocument. 4.2 Sync 1 inversion and randomization This unit shall invert the Sync 1 byte according to the MPEG-2 framing structure, and randomizes the data stream for spectrum shaping purposes. 4.3 Reed-Solomon (RS) coder This unit shall apply a shortened Reed-Solomon (RS) code to each randomized tran
35、sport packet to generate an error- protected packet. This code shall also be applied to the Sync byte itself. 4.4 Co nvo I ut i o na I i n t e r I e ave r This unit shall perform a depth I = 12 convolutional interleaving of the error-protected packets. The periodicity of the sync bytes shall remain
36、unchanged. 4.5 Byte to m-tuple conversion This unit shall perform a conversion of the bytes generated by the interleaver into QAM symbols. 4.6 Differential encoding In order to get a rotation-invariant constellation, this unit shall apply a differential encoding of the two Most Significant Bits (MSB
37、s) of each symbol. 4.7 Baseband shaping This unit performs mapping from differentially encoded m-tuples to I and Q signals and a square-root raised cosine filtering of the I and Q signals prior to QAM modulation. 4.8 QAM modulation and physical interface This unit performs QAM modulation. It is foll
38、owed by interfacing the QAM modulated signal to the Radio Frequency (FW) cable channel. 4.9 Cable receiver A System receiver shall perform the inverse signal processing, as described for the modulation process above, in order to recover the baseband signal. 5 M PEG-2 transport layer The MPEG-2 Trans
39、port Layer is defined in ISOIEC 13818-1 i. The Transport Layer for MPEG-2 data is comprised of packets having 188 bytes, with one byte for synchronization purposes, three bytes of header containing service identification, scrambling and control information, followed by 184 bytes of MPEG-2 or auxilia
40、ry data. ETSI STD-ETSI / /I I/ R R R - Sync 187 Bytes Sync2 187 Bytes Sync8 187 Bytes / I/ EN R - / Sync 187 Bytes / 300 Syncl w Sync n _ 429-ENGL RS(204,188,8) R 187 Bytes 1998 3400855 / Syncl Syncl or 203 Bytes OT 203 Bytes Sync n 0284873 079 Syncl or Sync n Il 9 EN 300 429 V1.2.1 (1998-04) 6 Fram
41、ing structure The framing organization shall be based on the MPEG-2 transport packet structure. The System framing structure is shown on figure 2. 187 Bytes Sync 1 byte Figure 2a) MPEG-2 transport MUX packet 204 bytes Figure 2c) Reed-Solomon RS(204,188, T=8) error protected packet Figure 2d) Interle
42、aved Frames; Interleaving depth 1=12 bytes Syncl = not randomized complemented sync byte Sync n = not randomized sync byte, n = 2, 3, ., Figure 2: Framing structure STD-ETSI EN 300 429-ENGL 1998 3400855 0284872 TO5 W 31 2 3 4 6 6 7 8 9 1OJi 121314 16 10 EN 300 429 V1.2.1 (1998-04) 0000001 1 di( GR (
43、t - 7 Channel coding To achieve the appropriate level of error protection required for cable transmission of digital data, a FEC based on Reed-Solomon encoding shall be used. In contrast to the Baseline System for satellite described in ETS 300 421 3, no convolutional coding shall be applied to cabl
44、e transmission. Protection against burst errors shall be achieved by the use of byte interleaving. 7.1 Randomization for spectrum shaping The System input stream shall be organized in fixed length packets (see figure 2), following the MPEG-2 transport multiplexer. The total packet length of the MPEG
45、-2 transport MUX packet is 188 bytes. This includes 1 sync-word byte (i.e. 47HEx). The processing order at the transmitting side shall always start from the MSB (i.e. O) of the sync word-byte (i.e. O10001 11). In order to comply with the System for satellite in ETS 300 421 3 and to ensure adequate b
46、inary transitions for clock recovery, the data at the output of the MPEG-2 transport multiplex shall be randomized in accordance with the configuration depicted in figure 3. The polynomial for the Pseudo Random Binary Sequence (PRBS) generator shall be: 1 + x4+ x5 DatainputrnSBfmt): 101/11000 x x xI
47、x x x x x I PRBSsequence : l o o O10 o o 1 1 l Figure 3: Scrambler/descrambler schematic diagram The first bit at the output of the PRBS generator shall be applied to the first bit of the first byte following the inverted MPEG-2 sync byte (i.e.B8 =). To aid other synchronization functions, during th
48、e MPEG-2 sync bytes of the subsequent 7 transport packets, the PRBS generation continues, but its output shall be disabled, leaving these bytes unrandomized. The period of the PRBS sequence shall therefore be 1 503 bytes. The randomization process shall be active also when the modulator input bit-st
49、ream is nonexistant, or when it is non- compliant with the MPEG-2 transport stream format (i.e. 1 sync byte + 187 packet bytes). This is to avoid the emission of an unmodulated carrier from the modulator. ETSI STD.ETS1 EN 300 429-ENGL 1998 = 3400855 0284873 941 - 7.2 3 e 17x3 _ 11 17x1 1 FIFO shift registe Interleaver 1=12 De-interleaver I=12 11 EN 300 429 V1.2.1 (1998-04) Reed-Solomon coding Following the energy dispersal randomization process, systematic shortened Reed-
