1、 STD-ETSI EN 300 749-ENGL 1777 3400855 O2L77L7 387 EN 300 749 1.1.2 (1997-08) , I European Standard (Telecommunications series) Digital Video Broadcasting (DVB); Microwave Multipoint Distribution Systems (MMDS) below 10 GHz STD-ETSI EN 300 747-ENGL 1797 3400855 0237720 DTO EN 300 749 V1.1.2 (1 997-0
2、8) 2 Reference REN/JTC-OODVB-69 (6xoOOidc.PDF) Keywords DVB, digital, video, broadcasting, MPEG, TV, multipoint ETSI Secretariat 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 As
3、sociation but non lucratif enregistre a la Sous-Prfecture de Grasse (06) N“ 7803/88 Tel.: +33 4 92 94 42 O0 Fax: +33 4 93 65 47 16 X.400 c= fr; a=atlas; p=etsi; s=secretariat Internet secretariat et.si.fr http:/www.etsi .f r Copyright Notification No part may be reproduced except as authorized by wr
4、itten permission. The copyright and the foregoing restriction extend to reproduction in ail media. O European Telecommunications Standards Institute 1997. O European Broadcasting Union 1997. All rights reserved. STD-ETSI EN 300 747-ENGL 1777 m 3400855 0237723 TI7 3 EN 300 749 V1.1.2 (1 997-08) Conte
5、nts Intellectual Property Rights 4 Foreword 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 Normative references . 5 Symbols and abbreviations 5 Abbreviations 6 MMDS System concept . 6 Baseband interfacing and sync . 8 Sync 1 inversion and randomization . . 8 Reed
6、-Solomon (RS) encoder . 8 convolutional interieaver . 8 Byte to m-tuple conversion 8 Differential encoding . 8 Baseband shaping 8 QAM modulation and physical interface . . 8 MMDS receiver . . 8 MPEG-2 transport layer . 8 Framing structure . 9 Channel coding 9 Randomization for spectrum shaping Reed-
7、Solomon (RS) encoding . 11 Convolutional interleaving . 11 Byte-to-symbol mapping 12 Modulation . 13 Symbols 5 Annex A (normative): Baseband filter characteristics . 16 Annex B (informative): Transparency of MMDS networks 17 Annex C (informative): Bibliography . 18 History 19 STD.ETS1 EN 300 749-ENG
8、L 1777 m 3400855 0237722 973 4 EN 300 749 V1.1.2 (1 997-08) 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 any, is publicly available for ETSI members and non-members
9、, and can be found in ETR 314: “intellectual Property Rights (IPRs); Essential, or potentially Essential, iPRs notified to ETSI in respect of ETSI standards“, which is available free of charge from the ETSI Secretariat. Latest updates are available on the ETSI Web server (http:/www.etsi.fi/ipr). Pur
10、suant to the ETSI Interim IPR 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 3 14 (or the updates on http:/www.etsi.fr/ipr) which are, or may be, or may become, essential to the present
11、 document. Foreword This second edition, previously as an ETS now an EN, contains changes of an entirely editorial nature as follows: 1) add the DVB logo to the front page of the deliverable; 2) change the title from: “Digital broadcasting systems for television, sound and data services; etc.“ to 3)
12、 add in the foreword the DVB acknowledgement. “Digital Video Broadcast (DVB); etc.“; 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
13、 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
14、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
15、U has active members in about 60 countries in the European broadcasting area; its headquarters is in Geneva *. * European Broadcasting Union Case Postale 67 CH-1218 GRAND SACONNEX (Geneva) Switzerland Tel: 41 22717 21 11 Fax: +41 22 717 24 81 Digital Video Broadcasting (DVB) Project Founded in Septe
16、mber 1993, the DVB 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 aroun
17、d the world, DVB fosters market- led systems, which meet the real needs, and economic circumstances, of the consumer electronics and the broadcast industry. Proposed national transposition dates Date of adoption of this EN: Date of latest announcement of this EN (doa): 4 April 1997 31 July 1997 Date
18、 of latest publication of new National Standard or endorsement of this EN (dop/e): 31 January 1998 Date of withdrawal of any conflicting National Standard (dow): 31 January 1998 STD-ETSI EN 300 747-ENGL I997 m 3400855 0217723 BOT 5 EN 300 749 V1.1.2 (1 997-08) 1 Scope The present document describes
19、the framing structure, channel coding and modulation (denoted “the System“ for the purposes of the present document) for a digital multi-program television distribution by Microwave Multipoint Distribution Systems (MMDS) operating below 10 GHz. The aim of the present document is to present a harmoni
20、zed transmission standard for cable, satellite and MMDS, based on the MPEG-2 System Layer ISO/iEC 13818-1 i, with the addition of appropriate Forward Error Correction (FEC) technique. This System follows the modulationchannel coding system for digital multi-program television by cable EN 300 429 (se
21、e annex C, bibliography) and is based on Quadrature Amplitude Modulation (QAM) with 16, 32, and 64 constellation points. The System FEC is designed to improve Bit Error Ratio (BER) from 10 -4 to a range, “Quasi Error Free“ (QEF) operation with approximately one uncorrected error event per transmissi
22、on hour. to lo-“, ensuring 2 Normative 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 to and inclu
23、ding 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 which case the l
24、atest 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. u1 Pl ISO/EC 13818-1: “Coding of moving pictures and associated audio“. IEEE Trans. Comm. Tech., COM-19, pp. 772-781, (October 1971) Forney, G.D.: “Burst-
25、correcting codes for the classic bursty channel“. 3 3.1 Symbols Symbols and abbreviations For the purposes of the present document, the following symbols apply: roll-off factor Most Significant Bits (MSB) at the output of the byte to m-tuple converter channel centre frequency Nyquist frequency Reed
26、- Solomon (RS) code generator polynomial HEXadec i mal Interleaving depth (bytes) In-phase, Quadrature phase components of the modulated signal branch index number of bytes mapped into n symbols power of 2m-level QAM: 4,5,6 for 16-QAM, 32-QAM, M-QAM, respectively STD.ETS1 EN 300 749-ENGL 1797 = 3400
27、855 0237724 746 3.2 6 EN 300 749 Vi .i .2 (1 997-08) convolutional interleaver branch depth for j = 1, M = N/I number of symbols mapped from k bytes error protected frame length (bytes) RS field generator polynomial in-band ripple (dB) Randomized sequence symbol Rate corresponding to the bilateral N
28、yquist bandwidth of the modulated signal useful bit Rate after MPEG-2 transport multiplexer bit Rate after RS outer encoder number of differentially uncoded bits: 2,3,4 for 16-QAM, 32-QAM, 64-QAM, respectively number of bytes which can be corrected in RS error protected packet symbol period Abbrevia
29、tions For the purposes of the present document, the following abbreviations apply: BB BER D/A FEC FIFO IF IRD LSB MMDS MPEG MSB MUX PDH PRBS QAM QEF RF RS SMATV TDM TV BaseBand Bit Error Ratio Digital -to-Analogue conversion Forward Error Correction First In First Out intermediate Frequency integrat
30、ed Receiver Decoder Least Significant Bit Microwave Multipoint Distribution Systems Moving Pictures Experts Group Most Significant Bit MU1 t ipleX Plesiochronous Digital Hierarchy Pseudo-Random Binary Sequence Quadrature Amplitude Modulation Quasi Error Free Radio Frequency Reed-S olomon Satellite M
31、aster Antenna Television Time Division Multiplex Television 4 MMDS System concept The MMDS System shall be defined as the functional block of equipment performing the adaptation of the baseband TV signals to the MMDS channel characteristics (see figure 1). At the transmitter site, the following TV b
32、aseband signal sources can be considered: - satellite signal(s); - cable signal(s); - contribution link(s); - local program source(s). The processes in the following subclauses shall be applied as shown in figure 1. STD-ETSI EN 300 749-ENGL L97 m 3400855 0237725 b82 9 7 . . e, E- m -i I I -* u -_- i
33、l *I I I 4 EN 300 749 V1.1.2 (1997-08) . -I QI 2 2.; 8 OaiS $04 Figure 1 : Conceptual block diagram of elements at the transmitting and receiving sites of MMDS systems below 10 GHz STD.ETSI EN 300 7Li7-ENGL 1777 3400855 021772b 517 8 EN 300 749 V1.1.2 (1997-08) 4.1 Baseband interfacing and sync This
34、 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 document. 4.2 Sync 1 inversion and randomization This unit shall invert the Sync 1 byte
35、 according to the MPEG-2 framing structure, and ran-dmizes the data stream for spectrum shaping purposes. 4.3 Reed-Solomon (RS) encoder This unit shall apply a shortened RS code to each randomized transport packet to generate an error-protected packet. This code shall also be applied to the Sync byt
36、e itself. 4.4 Convolutional interleaver This unit shall perform a depth I = 12 convolutional interleaving of the error-protected packets. The periodicity of the sync bytes shall remain unchanged. 4.5 Byte to m-tuple conversion This unit shall perform a conversion of the bytes generated by the interl
37、eaver into QAM symbols. 4.6 Differential encoding In order to get a rotationally-invariant constellation, this unit shall apply a differential encoding to the two Most Significant Bits (MSBs) of each symbol. 4.7 Baseband shaping This unit performs mapping from differentially encoded m-tuples to filt
38、ering of the I and Q signals prior to QAM modulation. 4.8 QAM modulation and physical and Q signals and a squawroot raised cosine nterface This unit performs QAM modulation. It is followed by interfacing the QAM modulated signal to the Radio Frequency (RF) MMDS channel. 4.9 MMDS receiver A System re
39、ceiver shall perform the inverse signal processing, as described for the modulation process above, in order to recover the baseband signal. 5 MPEG-2 transport layer The MPEG-2 Transport Layer is defined in ISO/EC 13818-1 i. The Transport Layer for MPEG-2 data is comprised of packets having 188 bytes
40、, 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 auxiliary data. STD-ETSI EN 300 7Li-ENGL 1997 m 3400855 0217727 455 W II II - 4t R R R Sync 187 bytes sync2 187 bytes 187 byte
41、s II 9 EN 300 749 V1.1.2 (1997-08) - R 187 bytes I 6 Framing structure - - Syncl II sv nc n Svnc n or 203 bytes or 203 bytes The framing organization shall be based on the MPEG-2 transport packet structure. The System framing structure is shown in figure 2. Sync1 or Svncn 11 187 bytes Sync 1 byte Fi
42、gure 2a) MPEG-2 transport MUX packet I 204 bytes I RS(204,188,8) Syncl R Svnc n or 187 bytes Figure 2c) Reed-Solomon RS(204,188, T = 8) error protected packet - Syncl = nonrandomized complemented sync byte Syncn = nonrandomized sync byte, n = 2,3, ., 8 Figure 2: Framing structure 7 Channel coding To
43、 achieve the appropriate level of error protection required for MMDS transmission of digital data, a FEC based on RS encoding shall be used. In contrast to the baseline system for satellite described in EN 300 421 (see annex C, bibliography), no convolutional coding shall be applied for MMDS transmi
44、ssion. Protection against burst errors shall be achieved by the use of byte interleaving. 10 EN 300 749 V1.1.2 (1 997-08) + 7.1 Randomization for spectrum shaping The System input stream shall be organized in fixed length packets (see figure 21, following the MPEG-2 transport multiplexer. The total
45、packet length of the MPEG-2 transport MUX packet is 188 bytes. This includes 1 sync-word byte (Le. 47 =). 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). 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15+ in order to comply with the Sy
46、stems for satellite and cable (see EN 300 421 and EN 300 429 in annex C, bibliography) and to ensure adequate binary 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
47、for the Pseudo Random Binary Sequence (PRBS) generator shall be: 1 + x4 + x15. 41 I Qk Mapping B, = b, Differential encoding Ik A, = MSB Q NOTE 1 : bO shall be understood as being the Least Significant Bit (LSB) of each byte or m-tuple. NOTE 2: In this conversion, each byte results in more than one
48、m-tuple, labelled Z, Z + 1, etc. with 2 being transmitted before Z + 1. Figure 5: Byte to m-tuple conversion for 64-QAM The two MSB of each symbol shall then be differentially encoded in order to obtain a IC /2-rotation-invariant QAM constellation. The differential encoding of the two MSBs shall be
49、given by the following Boolean expression: NOTE: For the above Boolean expression I “ denotes the EXOR function, “+“ denotes the logical OR function, “.“ denotes the logical AND function and the overbar denotes inversion. Figure 6 gives an example of implementation of byte-to-symbol conversion. from convolutional interleaver Figure 6: Example implementation of the byte to m-tuple conversion and the differential encoding of the two MSBs STD-ETSI EN 300 747-ENGL 3777 34130855 0237733 78b 2 3 4 13 EN 300 749 V1.1.2 (1997-08) 10 +id2 11 +
