1、 ETSI TS 102 427 V1.1.1 (2005-07)Technical Specification Digital Audio Broadcasting (DAB);Data Broadcasting - MPEG-2 TS streamingEuropean Broadcasting Union Union Europenne de Radio-Tlvision EBUUER ETSI ETSI TS 102 427 V1.1.1 (2005-07) 2 Reference DTS/JTC-DAB-40 Keywords audio, broadcasting, DAB, di
2、gital, MPEG ETSI 650 Route des Lucioles F-06921 Sophia Antipolis Cedex - FRANCE Tel.: +33 4 92 94 42 00 Fax: +33 4 93 65 47 16 Siret N 348 623 562 00017 - NAF 742 C Association but non lucratif enregistre la Sous-Prfecture de Grasse (06) N 7803/88 Important notice Individual copies of the present do
3、cument can be downloaded from: http:/www.etsi.org The present document may be made available in more than one electronic version or in print. In any case of existing or perceived difference in contents between such versions, the reference version is the Portable Document Format (PDF). In case of dis
4、pute, the reference shall be the printing on ETSI printers of the PDF version kept on a specific network drive within ETSI Secretariat. Users of the present document should be aware that the document may be subject to revision or change of status. Information on the current status of this and other
5、ETSI documents is available at http:/portal.etsi.org/tb/status/status.asp If you find errors in the present document, please send your comment to one of the following services: http:/portal.etsi.org/chaircor/ETSI_support.asp Copyright Notification No part may be reproduced except as authorized by wr
6、itten permission. The copyright and the foregoing restriction extend to reproduction in all media. European Telecommunications Standards Institute 2005. European Broadcasting Union 2005. All rights reserved. DECTTM, PLUGTESTSTM and UMTSTM are Trade Marks of ETSI registered for the benefit of its Mem
7、bers. TIPHONTMand the TIPHON logo are Trade Marks currently being registered by ETSI for the benefit of its Members. 3GPPTM is a Trade Mark of ETSI registered for the benefit of its Members and of the 3GPP Organizational Partners. ETSI ETSI TS 102 427 V1.1.1 (2005-07) 3 Contents Intellectual Propert
8、y Rights4 Foreword.4 1 Scope 5 2 References 5 3 Definitions and abbreviations.5 3.1 Definitions5 3.2 Abbreviations .5 4 Introduction 6 5 Error Protection for DAB MSC stream data sub-channels and transport packets of 188 bytes.6 5.1 General considerations .6 5.2 Outer Coding6 5.3 Outer Interleaver.7
9、5.4 Transmission 8 History 9 ETSI ETSI TS 102 427 V1.1.1 (2005-07) 4 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
10、-members, and can be found in ETSI SR 000 314: “Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respect of ETSI standards“, which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web server (http:/webapp.etsi.org/IPR/
11、home.asp). Pursuant to the ETSI 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 ETSI SR 000 314 (or the updates on the ETSI Web server) which are, or may be, or may become, essential to
12、the present document. Foreword This Technical Specification (TS) has been produced by Joint Technical Committee (JTC) Broadcast of the European Broadcasting Union (EBU), Comit Europen de Normalisation ELECtrotechnique (CENELEC) and the European Telecommunications Standards Institute (ETSI). NOTE 1:
13、The EBU/ETSI JTC Broadcast was established in 1990 to co-ordinate the drafting of standards in the specific field of broadcasting and related fields. Since 1995 the JTC Broadcast became a tripartite body by including in the Memorandum of Understanding also CENELEC, which is responsible for the stand
14、ardization 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, program-making and program-exchange domains. The EBU has active members in about 60 countries in
15、the European broadcasting area; its headquarters is in Geneva. European Broadcasting Union CH-1218 GRAND SACONNEX (Geneva) Switzerland Tel: +41 22 717 21 11 Fax: +41 22 717 24 81 The Eureka Project 147 was established in 1987, with funding from the European Commission, to develop a system for the br
16、oadcasting of audio and data to fixed, portable or mobile receivers. Their work resulted in the publication of European Standard, EN 300 401 1, for DAB (see note) which now has worldwide acceptance. The members of the Eureka Project 147 are drawn from broadcasting organizations and telecommunication
17、 providers together with companies from the professional and consumer electronics industry. NOTE 2: DAB is a registered trademark owned by one of the Eureka Project 147 partners. ETSI ETSI TS 102 427 V1.1.1 (2005-07) 5 1 Scope The present document specifies how MPEG-2 Transport Stream can be encapsu
18、lated within a DAB MSC stream data sub-channel including additional error protection. The error protection mechanism is composed of a Reed-Solomon coder and an interleaver. 2 References The following documents contain provisions, which, through reference in this text, constitute provisions of the pr
19、esent document. References are either specific (identified by date of publication and/or edition number or version number) or non-specific. For a specific reference, subsequent revisions do not apply. For a non-specific reference, the latest version applies. Referenced documents which are not found
20、to be publicly available in the expected location might be found at http:/docbox.etsi.org/Reference. 1 ETSI EN 300 401: “Radio Broadcasting Systems; Digital Audio Broadcasting (DAB) to mobile, portable and fixed receivers“. 2 ETSI EN 300 744: “Digital Video Broadcasting (DVB); Framing structure, cha
21、nnel coding and modulation for digital terrestrial television“. 3 ISO/IEC 13818 (Parts 1 to 3): “Information technology - Generic coding of moving pictures and associated audio information“. 3 Definitions and abbreviations 3.1 Definitions For the purposes of the present document, the following defin
22、ition applies: Transport stream (TS) multiplexer: device that combines multiple elementary streams into a Transport Stream (TS) for delivery through a single transmission path (see ISO/IEC 13818 3) 3.2 Abbreviations For the purposes of the present document, the following abbreviation applies: DAB Di
23、gital Audio Broadcasting ETSI ETSI TS 102 427 V1.1.1 (2005-07) 6 4 Introduction The DAB system EN 300 401 1 defines the way that audio (programme) and data services may be carried. However, in MSC stream mode, the error protection scheme is optimised for audio services. Data services carried in stre
24、am mode (for example video services) require additional error protection and this can be achieved by applying an outer coding to the data packets before insertion into a DAB MSC stream mode sub-channel. In order to provide as much commonality in transmission and reception equipment as possible, the
25、outer coding is taken directly from DVB-T EN 300 744 2, which also needs to provide appropriate error protection. The system is defined as a functional block that performs the addition of outer coding (Reed-Solomon code) and outer interleaving (convolutional interleaving). This functional block sits
26、 between the output of the MPEG-2 transport multiplexer and the input to a stream sub-channel of a DAB multiplexer, see figure 1. MPEG-2 transport multiplexer Scope of present document Reed-Solomon outer coder Outer Interleaver DAB main service channel multiplexer Figure 1: Conceptual diagram of the
27、 outer coder and interleaver The process is identical to that specified in EN 300 744 2 clause 4.3.2. NOTE: No energy dispersal scrambling is performed because this is provided by the DAB system; therefore no inverted SYNC bytes are required. 5 Error Protection for DAB MSC stream data sub-channels a
28、nd transport packets of 188 bytes 5.1 General considerations Each input transport packet is 188 bytes long and starts with a synchronizing byte of value 0x47. The transport packet may contain any data. See ISO/IEC 13818 3 for more details of the format of transport packets. 5.2 Outer Coding The oute
29、r coding and interleaving shall be performed on the input transport packet (see figure 2). Sync byte 0x47 MPEG-2 transport stream data (187 bytes) Figure 2: Input transport packet ETSI ETSI TS 102 427 V1.1.1 (2005-07) 7 Reed-Solomon RS (204,188, t = 8) shortened code (see note), derived from the ori
30、ginal systematic RS (255,239, t = 8) code, shall be applied to each transport packet (188 bytes) to generate an error protected packet (see figure 3). Reed-Solomon coding shall also be applied to the packet synchronizing byte (i.e. 0x47). NOTE: The Reed-Solomon code has length 204 bytes, dimension 1
31、88 bytes and allows the correction of up to 8 random erroneous bytes in a received word of 204 bytes. Code Generator Polynomial: g(x) = (x+0)(x+1)(x+2).(x+15), where = 2. Field Generator Polynomial: p(x) = x8+ x4+ x3+ x2+ 1. The shortened Reed-Solomon code may be implemented by adding 51 bytes, all
32、set to zero, before the information bytes at the input of an RS (255,239, t = 8) encoder. After the RS coding procedure these null bytes shall be discarded, leading to a RS code word of N = 204 bytes. Sync byte 0x47 MPEG-2 transport stream data (187 bytes) parity word (16 bytes) 204 bytes Figure 3:
33、Error protected packet 5.3 Outer Interleaver The convolutional byte-wise interleaver shall be based on the Forney approach with the interleaving depth I = 12 bytes as shown in figure 4. Figure 4: Conceptual diagram of the outer interleaver and deinterleaver Following the conceptual scheme of figure
34、4, convolutional byte-wise interleaving with depth I = 12 shall be applied to the error protected packets. This results in the interleaved data structure (see figure 5). The convolutional interleaving process shall be based on the Forney approach, which is compatible with the Ramsey type III approac
35、h, with I = 12. The interleaver may be composed of I = 12 branches, cyclically connected to the input byte-stream by the input switch. Each branch j shall be a First-In, First-Out (FIFO) shift register, with depth j M cells where M = 17 = N/I, N = 204. The cells of the FIFO shall contain 1 byte and
36、the input and output switches shall be synchronized. ETSI ETSI TS 102 427 V1.1.1 (2005-07) 8 For synchronization purposes, the SYNC bytes shall always be routed in the branch “0“ of the interleaver (corresponding to a null delay). NOTE: The deinterleaver is similar in principle to the interleaver, b
37、ut the branch indices are reversed (i.e. j = 0 corresponds to the largest delay). The deinterleaver synchronization can be carried out by routing the first recognized sync byte in the “0“. Sync byte 0x47 RS encoded, interleaved data (203 bytes) 204 bytes Figure 5: Interleaved packet 5.4 Transmission
38、 The interleaved packets are inserted into the MSC stream mode data sub-channel. The use of the outer coding and interleaving scheme is specified by the user application. No additional signalling is required. ETSI ETSI TS 102 427 V1.1.1 (2005-07) 9 History Document history V1.1.1 July 2005 Publication
