1、 ETSI TS 101 191 V1.4.1 (2004-06)Technical Specification Digital Video Broadcasting (DVB);DVB mega-frame for Single Frequency Network (SFN)synchronizationEuropean Broadcasting Union Union Europenne de Radio-Tlvision EBUUER ETSI ETSI TS 101 191 V1.4.1 (2004-06) 2 Reference RTS/JTC-DVB-164 Keywords br
2、oadcasting, digital, DVB, TV, video 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
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5、tatus of this and other ETSI documents is available at http:/portal.etsi.org/tb/status/status.asp If you find errors in the present document, send your comment to: editoretsi.org Copyright Notification No part may be reproduced except as authorized by written permission. The copyright and the forego
6、ing restriction extend to reproduction in all media. European Telecommunications Standards Institute 2004. European Broadcasting Union 2004. All rights reserved. DECTTM, PLUGTESTSTM and UMTSTM are Trade Marks of ETSI registered for the benefit of its Members. TIPHONTMand the TIPHON logo are Trade Ma
7、rks 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 101 191 V1.4.1 (2004-06) 3 Contents Intellectual Property Rights4 Foreword.4 1 Scope 5 2 References 5
8、3 Definitions and abbreviations.5 3.1 Definitions5 3.2 Abbreviations .5 4 General description.6 5 Mega-frame definition8 6 Mega-frame Initialization Packet (MIP) 9 6.1 Functions 12 6.1.1 Transmitter time offset function .12 6.1.2 Transmitter frequency offset function.12 6.1.3 Transmitter power funct
9、ion.13 6.1.4 Private data function .13 6.1.5 Cell id function .13 6.1.6 Enable function.14 6.1.7 Bandwidth function.14 Annex A (normative): CRC decoder model.15 Annex B (normative): Functional description of SFN synchronization16 Annex C (normative): Reconfiguration of DVB-T modulator parameters by
10、using the MIP 17 History 18 ETSI ETSI TS 101 191 V1.4.1 (2004-06) 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-
11、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/h
12、ome.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 t
13、he 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: The
14、 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 standard
15、ization 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 EBU has active members in about 60 countries in
16、 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 Founded in September 1993, the DVB Project is a market-led consortium of public and private sector organizations in the
17、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 fosters market-led systems, which meet the real needs, and economic circumstances, of t
18、he consumer electronics and the broadcast industry. ETSI ETSI TS 101 191 V1.4.1 (2004-06) 5 1 Scope The present document specifies a mega-frame, including a Mega-frame Initialization Packet (MIP), which may be used for synchronization of Single Frequency Networks (SFN) as well as for the optional co
19、ntrol of other important parameters in an SFN. 2 References The following documents contain provisions which, through reference in this text, constitute provisions of the present document. References are either specific (identified by date of publication and/or edition number or version number) or n
20、on-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 to be publicly available in the expected location might be found at http:/docbox.etsi.org/Reference. 1 ISO/IEC 13818-1 (1994):
21、“Information technology - Generic coding of moving pictures and associated audio - Part 1: Systems“. 2 ETSI EN 300 744: “Digital Video Broadcasting (DVB); framing structure, channel coding and modulation for digital terrestrial television“. 3 ETSI EN 300 468: “Digital Video Broadcasting (DVB); Speci
22、fication for Service Information (SI) in DVB systems“. 3 Definitions and abbreviations 3.1 Definitions For the purposes of the present document, the following terms and definitions apply: cell: See EN 300 468 3, clause 3.1. DVB-T frame: See EN 300 744 2, clause 4.4. DVB-T super-frame: See EN 300 744
23、 2, clause 4.4. 3.2 Abbreviations For the purposes of the present document, the following abbreviations apply: CRC Cyclic Redundancy Check DVB Digital Video Broadcasting DVB-T DVB-Terrestrial ERP Effective Radiated Power GPS Global Positioning System HP High Priority LP Low PriorityMFN Multi Frequen
24、cy Network MIP Mega-frame Initialization Packet MPEG Moving Pictures Expert Group ETSI ETSI TS 101 191 V1.4.1 (2004-06) 6 MSB Most Significant Bit PID Packet IDentifier pps pulse per second RF Radio Frequency RS Reed-Solomon RX Receiver SFN Single Frequency Network SI Service Information STS Synchro
25、nization Time Stamp SYNC SYNChronization TPH Transport Packet Header TPS Transport Parameter Signalling TS Transport StreamTX Transmitter 4 General description Figure 1 shows a block diagram of a complete SFN system. MPEG-2remultiplexerSFNadapterMPEG-2TSTXNetworkadapterDistributionNetworkRXNetworkad
26、apterRXNetworkadapterGPS (note)10 MHz1 ppsDVB-TmodulatorSYNCsystemGPS (note)10 MHz 1 ppsDVB-TmodulatorSYNCsystemGPS (note)10 MHz 1 ppsMPEG-2TSMPEG-2TSNOTE: Could be any common available frequency reference. Figure 1: DVB-T primary distribution with SFN adaptation The SFN functionality is an extensio
27、n to the DVB system. The blocks associated with SFN functionality are the grey boxes in figure 1. These blocks could be implemented either as separate equipment or integrated in the multiplexer and/or the DVB-T modulator. SFN system blocks MPEG-2 re-multiplexer The MPEG-2 re-multiplexer re-multiplex
28、es the programmes from various input channels, updates the SI and provides an MPEG-2 TS, which, after SFN adaptation, is transmitted via the DVB-T modulators in the SFN. ETSI ETSI TS 101 191 V1.4.1 (2004-06) 7 SFN adapter The SFN adapter forms a mega-frame, consisting of n TS-packets corresponding t
29、o 8 DVB-T frames in the 8K mode or 32 frames in the 2K mode, and inserts a Mega-frame Initialization Packet (MIP) with a dedicated PID value. Inserted anywhere within a mega-frame of index M, the MIP of that mega-frame, MIPM, allows to uniquely identify the starting point (i.e. the first packet) of
30、the mega-frame M+1. This is accomplished by using a pointer carried by the MIPMitself to indicate its position with regards to the start of the mega-frame M+1. The time difference between the latest pulse of the “one-pulse-per-second“ reference, derived e.g. from GPS, that precedes the start of the
31、mega-frame M+1 and the actual start (i.e. first bit of first packet) of this mega-frame M+1 is copied into the MIPM. This parameter is called Synchronization Time Stamp (STS). The time duration of a mega-frame is only dependent on the channel bandwidth and the guard interval proportion, i.e. the meg
32、a-frame duration is independent of the duration TU, constellation and code rate of the DVB-T signal. The mega-frame durations are provided below for all combinations of channel bandwidth and guard interval proportion provided by EN 300 744 2 (exact values, except where otherwise stated): Table 1a: M
33、ega-frame duration for all combinations of channel bandwidth and guard interval proportions Channel bandwidth Guard Interval 8 MHz 7 MHz 6 MHz 5 MHz / TU = 1/32 0,5026560 s 0,5744640 s 0,6702080 s 0,8042496 s / TU = 1/16 0,5178880 s 0,5918720 s 0,6905173 s 0,8286208 s / TU = 1/8 0,5483520 s 0,626688
34、0 s 0,7311360 s 0,8773632 s / TU = 1/4 0,6092800 s 0,6963200 s 0,8123733 s 0,9748480 s NOTE: Approximate values in Italics. The output of the SFN adapter shall be fully DVB/MPEG-2 TS compliant. Transmitter/Receiver network adapter The network adapters shall provide a transparent link for the MPEG-2
35、TS from the central to the local units. The maximum network delay - caused by the different paths of the transmission network - the SYNC system can handle is 1 s. SYNC system The SYNC system will provide a propagation time compensation by comparing the inserted STS with the local time reference and
36、calculate the extra delay needed for SFN synchronization. See annex B for an example of the synchronization process. DVB-T modulator The modulator should provide a fixed delay from the input to the air interface. The information inserted in the MIP could be used for the direct control of the modulat
37、or modes or control of other transmitter parameters. The modulator clocks at the different sites have to be synchronized. Since it is a requirement of an SFN that all transmitted signals be identical, the MPEG-2 TS inputs to the various DVB-T modulators have to be bit identical. Global Positioning S
38、ystem (GPS) GPS is one among many possible time references but it is the only one available globally. GPS receivers are available which provide both a 10 MHz frequency reference and a 1 pulse per second (1 pps) time reference. The 1 pps time reference, used in SFN synchronization, is divided into 10
39、0 ns steps of the 10 MHz clock. The 10 MHz system clock is assumed to be available at all nodes in the network. The functional blocks “SFN adapter“ and “SYNC system“ are additional elements for SFN use, and not necessary in MFN applications. ETSI ETSI TS 101 191 V1.4.1 (2004-06) 8 5 Mega-frame defin
40、ition The output of the SFN adapter shall be a valid MPEG-2 TS, where the individual packets are organized in groups, which constitute a mega-frame. Each mega-frame consists of n packets, where n is an integer number, which depends on the number of RS-packets per super-frame in the DVB-T mode that w
41、ill be used for DVB-T emission of the MPEG-2 TS (see EN 300 744 2, clause 4.7). In the 8K mode n is (the number of RS-packets per super-frame) 2. In the 4K mode n is (the number of RS-packets per super-frame) 4. In the 2K mode n is (the number of RS-packets per super-frame) 8. Each mega-frame contai
42、ns exactly one Mega-frame Initialization Packet (MIP). The actual position may vary in an arbitrary way from mega-frame to mega-frame. The pointer value in the MIP is used to indicate the start of the following mega-frame. In figure 2 the overall structure of the mega-frame, including the positionin
43、g of the MIP, is given. The exact definition of the MIP format is given in clause 6. First Packet MIP Last Packet MFP #0 MFP #1 MFP #p MFP #n-1 MFP #0 Pointer = (n-1) - p The pointer indicates the location of the first packet of the next mega-frame. Mega-frame Figure 2: Overall mega-frame structure
44、The start of a mega-frame in the DVB-T signal is in the present document defined to coincide with the beginning of a DVB-T super-frame and the start of an inverted sync byte, being part of transport multiplex adaptation. The use of a mega-frame and the insertion of a MIP are additional elements for
45、SFN use, and not necessary in MFN applications. ETSI ETSI TS 101 191 V1.4.1 (2004-06) 9 6 Mega-frame Initialization Packet (MIP) The MIP is an MPEG-2 compliant Transport Stream (TS) packet, made up of a 4-byte header and a 184-byte data field. The organization of the MIP is shown in table 1b. Table
46、1b: Mega-frame Initialization Packet (MIP) Syntax Number of bits Identifier mega-frame_initialization_packet() transport_packet_header 32 bslbf synchronization_id 8 uimsbf section_length 8 uimsbf pointer 16 uimsbf periodic_flag 1 bslbf future_use 15 bslbf synchronization_time_stamp 24 uimsbf maximum
47、_delay 24 uimsbf tps_mip 32 bsblf individual_addressing_length 8 uimsbf for (i=0;iN;i+) tx_identifier 16 uimsbf function_loop_length for(i=0;iN;i+) function() 8 uimsbf crc_32 32 rpchof for (i=0, iN,i+) stuffing_byte 8 uimsbf NOTE 1: Optional parameters are shown in italic. NOTE 2: All parameter valu
48、es in the MIPM apply to mega-frame M+1, i.e. to the mega-frame pointed out by the pointer, except for the tps_mip which describes the parameters of mega-frame M+2. See annex C for details. NOTE 3: For the definition of the CRC decoder model, see annex A. NOTE 4: The length of a MIP shall always be 1
49、88 bytes. transport_packet_header: The transport_packet_header shall comply with ISO/IEC 13818-1 1, clause 2.4.3.2, tables 3 and 4. The PID value for the Mega-frame initialization Packet (MIP) shall be 0 15. The payload_unit_start_indicator is not used by the SFN synchronization function and shall be set to 1. The transport_priority value is not used by the SFN synchronization function and shall be set to 1. The transport_scrambling_control value shall be set to 00 (not scrambled). The adaptat
