SIST-TS TS 101 191 V1.2.1:2005

• Abstract:

  This document specifies a mega-frame, including a Mega-frame Initialis ation Packet, MIP, which may be used for synchronisation of the Single Frequency Networks as well as for the optional control of other impor tant parameters in an SFN.

• Status: Published
• Publication Date: 31-Oct-2005
• ICS: 33.170 - Television and radio broadcasting
• Technical Committee: RES - Radio equipment and systems
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Nov-2005
• Due Date: 01-Nov-2005
• Completion Date: 01-Nov-2005
• Ref Project: ETSI TS 101 191 V1.2.1 (1997-04) - Digital Video Broadcasting (DVB); DVB mega-frame for Single Frequency Network (SFN) synchronization

SIST-TS TS 101 191 V1.2.1:2005 is a Slovenian standard published by SIST and identical to TS 101 191 Version 1.2.1. It specifies the DVB mega-frame and the Mega-frame Initialization Packet (MIP) used for synchronization of Digital Video Broadcasting (DVB) Single Frequency Networks (SFN), with optional control of transmitter parameters. It is aimed at people designing or operating DVB-T distribution and transmitter chains that must stay aligned from site to site.

What does SIST-TS TS 101 191 V1.2.1:2005 specify?

SIST-TS TS 101 191 V1.2.1:2005 specifies how to build a mega-frame and how to use the MIP to support SFN synchronization. The document is written for SFN use and notes that these elements are not needed for Multi Frequency Network (MFN) applications.

The standard is organized into six clauses and three normative annexes.

Annex	What it covers
Annex A	CRC decoder model
Annex B	Functional description of SFN synchronization
Annex C	Reconfiguration of DVB-T modulator parameters by using the MIP

What are the key requirements of SIST-TS TS 101 191 V1.2.1:2005?

The document ties SFN operation to a fixed packet structure, a defined timing reference, and a small set of optional transmitter-control functions. In practice, an implementation has to preserve TS integrity while also carrying timing and configuration data.

• Clause 4 defines the SFN adapter as the element that forms the mega-frame and inserts the MIP. The output must remain a valid MPEG-2 Transport Stream (TS), and the TS inputs to the DVB-T modulators have to be bit identical. This matters because all transmitters in the SFN must radiate the same content at the same time.

• Clause 5 states that each mega-frame contains exactly one MIP, and the MIP pointer identifies the start of the following mega-frame. The start of a mega-frame is defined to coincide with the beginning of a DVB-T super-frame and the start of an inverted sync byte. This gives every site a common frame boundary.

• Clause 6 defines the MIP as an MPEG-2 compliant TS packet with a 4-byte header and a 184-byte data field. The Transport Packet Header (TPH) rules follow ISO/IEC 13818-1, and the MIP uses a dedicated PID value. For implementers, this means the MIP is carried inside ordinary MPEG-2 transport packet rules rather than as a separate side channel.

• Clause 6 also fixes the main MIP fields: synchronization_id, section_length, pointer, periodic_flag, synchronization_time_stamp, maximum_delay, tps_mip, and optional transmitter addressing and function data. The synchronization_time_stamp and maximum_delay use 100 ns steps, and maximum_delay is sized to cover the longest network, modulator, transmitter, and feeder delay up to 1 second. In practice, the timing budget must match the real distribution network.

• Clause 6.1 defines four optional functions: transmitter time offset, transmitter frequency offset, transmitter power, and private data. These let the MIP carry control information for transmitter setup, rather than relying only on a separate management network.

• Annex A, Annex B, and Annex C support implementation and verification. Annex A gives the CRC decoder model used to validate the MIP, Annex B shows the synchronization calculation from STS and receive delay, and Annex C explains how tps_mip is used to reconfigure DVB-T modulator parameters without ambiguity.

What terms does SIST-TS TS 101 191 V1.2.1:2005 define?

• Single Frequency Network (SFN) - A network in which transmitters radiate the same DVB-T signal on the same frequency and must stay synchronized.
• Mega-frame Initialization Packet (MIP) - The special TS packet inserted into each mega-frame to carry SFN timing and optional control data.
• Synchronization Time Stamp (STS) - The timing value that records the offset between the reference pulse and the start of the next mega-frame.
• Transport Parameter Signalling (TPS) - The DVB-T signalling data that is mirrored in tps_mip for modulator control.
• Effective Radiated Power (ERP) - The transmitter power measure used by the transmitter power function.
• pulse per second (pps) - The one-second timing reference, often derived from GPS, used for SFN synchronization.
• Multi Frequency Network (MFN) - A network type for which the SFN-specific elements of this document are not required.

Who uses SIST-TS TS 101 191 V1.2.1:2005?

SIST-TS TS 101 191 V1.2.1:2005 is used by DVB-T network planners, broadcast engineers, multiplexer and modulator designers, transmitter manufacturers, and synchronization-system integrators. It is also relevant to test laboratories and technical buyers who need to check whether equipment can support SFN timing, MIP handling, and transmitter parameter control.

What changed in SIST-TS TS 101 191 V1.2.1:2005 from the previous edition?

The document history records an earlier publication, V1.1.1, in April 1997, and the V1.2.1 publication in April 1998.

Which standards are used with SIST-TS TS 101 191 V1.2.1:2005?

• ISO/IEC 13818-1 - Provides the MPEG-2 Systems rules used for the transport packet header in the MIP.
• EN 300 744 - Provides the DVB-T framing structure, channel coding, modulation, frame and super-frame definitions, and the TPS mapping referenced throughout the document.

What does the SIST-TS TS 101 191 V1.2.1:2005 document contain?

The document contains the MIP field layout, the signaling tables for mandatory parameters, and the optional transmitter-control functions in Clause 6. It also includes a CRC decoder model in Annex A and a synchronization timing diagram in Annex B, both of which support implementation and verification. Annex C gives a worked sequence for changing DVB-T modulator parameters through the MIP so that the new configuration takes effect at a defined mega-frame boundary.

SLOVENSKI STANDARD
01-november-2005
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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
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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

2 TS 101 191 V1.2.1 (1998-04)
Reference
RTS/JTC-DVB-80 (b1000ior.PDF)
Keywords
Broadcasting, digital, video, DVB, TV
ETSI Secretariat
Postal address
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Office address
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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.
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

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.

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
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

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.
...