ETSI TS 101 191 V1.2.1 (1997-04)

Digital Video Broadcasting (DVB); DVB mega-frame for Single Frequency Network (SFN) synchronization

RTS/JTC-DVB-80

Digitalna videoradiodifuzija (DVB) – Mega-struktura DVB za sinhronizacijo enofrekvenčnih omrežij (SFN)

General Information

• Status: Published
• Publication Date: 06-Apr-1998
• Technical Committee: BROADCAS - EBU/CENELEC/ETSI on Broadcasting
• Current Stage: 12 - Completion
• Due Date: 23-Apr-1998
• Completion Date: 07-Apr-1998
• Ref Project: SIST-TS TS 101 191 V1.2.1:2005 - Digital Video Broadcasting (DVB); DVB mega-frame for Single Frequency Network (SFN) synchronization

Standards Content (Sample)

SLOVENSKI STANDARD
SIST-TS TS 101 191 V1.2.1:2005
01-november-2005
'LJLWDOQDYLGHRUDGLRGLIX]LMD'9%±0HJDVWUXNWXUD'9%]DVLQKURQL]DFLMR
HQRIUHNYHQþQLKRPUHåLM6)1
Digital Video Broadcasting (DVB); DVB mega-frame for Single Frequency Network (SFN)
synchronization
Ta slovenski standard je istoveten z: TS 101 191 Version 1.2.1
ICS:
33.170 Televizijska in radijska Television and radio
difuzija broadcasting
SIST-TS TS 101 191 V1.2.1:2005 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TS TS 101 191 V1.2.1:2005

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SIST-TS TS 101 191 V1.2.1:2005
TS 101 191 V1.2.1 (1998-04)
Technical Specification
Digital Video Broadcasting (DVB);
DVB mega-frame for Single Frequency Network (SFN)
synchronization
European Broadcasting Union Union Européenne de Radio-Télévision
EBU
UER
European Telecommunications Standards Institute

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SIST-TS TS 101 191 V1.2.1:2005
2 TS 101 191 V1.2.1 (1998-04)
Reference
RTS/JTC-DVB-80 (b1000ior.PDF)
Keywords
Broadcasting, digital, video, DVB, TV
ETSI Secretariat
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Copyright Notification
No part may be reproduced except as authorized by written permission.
The copyright and the foregoing restriction extend to reproduction in all media.
© European Telecommunications Standards Institute 1998.
© European Broadcasting Union 1998.
All rights reserved.

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SIST-TS TS 101 191 V1.2.1:2005
3 TS 101 191 V1.2.1 (1998-04)
Contents
Intellectual Property Rights.4
Foreword .4
1 Scope.5
2 Normative references .5
3 Definitions and abbreviations .5
3.1 Definitions . 5
3.2 Abbreviations. 5
4 General description .6
5 Mega-frame definition .7
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 . 13
6.1.3 Transmitter power function . 13
6.1.4 Private data function. 13
Annex A (normative): CRC decoder model.14
Annex B (normative): Functional description of SFN synchronization .15
Annex C (normative): Reconfiguration of DVB-T modulator parameters by using the MIP .16
History.17

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SIST-TS TS 101 191 V1.2.1:2005
4 TS 101 191 V1.2.1 (1998-04)
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 any, is publicly available for ETSI members and non-members, 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.fr/ipr or http://www.etsi.org/ipr).
Pursuant 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 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This Technical Specification (TS) has been produced by the Joint Technical Committee (JTC) of the European
Broadcasting Union (EBU), Comité Européen de Normalisation ELECtrotechnique (CENELEC) and the European
Telecommunications Standards Institute (ETSI).
NOTE: The EBU/ETSI 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 CENELEC, 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 EBU 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: [phone]
Fax: [phone]
Digital Video Broadcasting (DVB) Project
Founded in September 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 Moving Pictures Expert Group
(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 the
consumer electronics and the broadcast industry.

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SIST-TS TS 101 191 V1.2.1:2005
5 TS 101 191 V1.2.1 (1998-04)
1 Scope
The present document specifies a mega-frame, including a Mega-frame Initialization Packet (MIP), which may be used
for synchronization of the Single Frequency Networks (SFN) as well as for the optional control of other important
parameters in an SFN.
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 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 which 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.
[1] ISO/IEC 13818-1 (1994): "Information Technology - Generic Coding of Moving Pictures and
Associated Audio: Systems".
[2] EN 300 744: "Digital Video Broadcasting (DVB); Framing structure, channel coding and
modulation for digital terrestrial television".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following definitions apply:
frame: For the definition of a DVB-Terrestrial (DVB-T) frame, see EN 300 744 [2], subclause 4.4.
super-frame: For the definition of a DVB-T super-frame, see EN 300 744 [2], subclause 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
MFN Multi Frequency Network
LP Low Priority
MFP Mega-Frame Packet
MIP Mega-frame Initialization Packet
MPEG Moving Pictures Expert Group
PID Packet IDentifier

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SIST-TS TS 101 191 V1.2.1:2005
6 TS 101 191 V1.2.1 (1998-04)
pps pulse per second
RF Radio Frequency
RS Reed-Solomon
SFN Single Frequency Network
SI Service Information
STS Synchronization Time Stamp
SYNC SYNChronization
TPH Transport Packet Header
TPS Transport Parameter Signalling
TS Transport Stream
TX/RX Transmitter/Receiver
4 General description
Figure 1 shows a block diagram of a complete SFN system.
MPEG-2
TS
RX
SYNC DVB-T
MPEG-2
Network
system
modulator
TS
adapter
10 MHz 1 pps
TX
MPEG-2 SFN
Distribution
GPS (note)
Network
remultiplexer adapter
Network
adapter
1 pps
10 MHz
RX
SYNC
DVB-T
Network
GPS (note) system modulator
adapter
10 MHz 1 pps
MPEG-2
TS
GPS (note)
NOTE: Could be any common available frequency reference.
Figure 1: DVB-T primary distribution with SFN adaptation
The SFN functionality is an extension 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-multiplexes the programmes from various input channels, updates the Service
Information (SI) and provides an MPEG-2 Transport Stream (TS) which, after SFN adaptation, is transmitted via the
DVB-T modulators in the SFN.
SFN adapter
The SFN adapter forms a mega-frame, consisting of n TS-packets corresponding to 8 DVB-T frames in the 8k mode or
32 frames in the 2k mode, and inserts a MIP with a dedicated Packet IDentifier (PID) value. Inserted anywhere within a

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SIST-TS TS 101 191 V1.2.1:2005
7 TS 101 191 V1.2.1 (1998-04)
mega-frame of index M, the MIP of that mega-frame, MIP , allows to uniquely identify the starting point (i.e. the first
M
packet) of the mega-frame M+1. This is accomplished by using a pointer carried by the MIP itself to indicate its
M
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 Global
Positioning System (GPS), that precedes the start of the 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 MIP . This parameter is called Synchronization Time Stamp (STS).
M
The time duration of a mega-frame is independent of the duration T , constellation and code rate of the DVB-T signal.
u
Four different time durations exist depending on the chosen guard interval proportion:
0,502656 s (D/T =1/32);
u
0,517888 s (D/T =1/16);
u
0,548352 s (D/T =1/8);
u
0,609280 s (D/T =1/4).
u
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 TS from the central to the local units. The
maximum network delay - caused by the different paths of the transmission network - the SYNChronization (SYNC)
system can handle is 1 second.
SYNC system
The SYNC system will provide a propagation time compensation by comparing the inserted STS with the local time
reference and 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 modulator 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 System (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 (pps) time reference. The 1 pps time
reference, used in SFN synchronization, is divided into 100 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
Multi Frequency Network (MFN) applications.
5 Mega-frame definition
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 Reed-Solomon (RS)-packets per super-frame in the DVB-T mode that will be used for DVB-T emission of
the MPEG-2 TS (see EN 300 744 [2], subclause 4.7). In the 8k mode n is (the number of RS-packets per super-frame) ·
2. In the 2k mode n is (the number of RS-packets per super-frame) · 8.
Each mega-frame contains exactly one 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 positioning of the MIP, is given. The exact definition of the MIP
format is given in clause 6.

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