SIST-TS TS 101 191 V1.4.1:2005
(Main)Digital Video Broadcasting (DVB); DVB mega-frame for Single Frequency Network (SFN) synchronization
- Abstract
Update to existing specification to incorporate elements of DVB-H
- Status
- Published
- Publication Date
- 31-Oct-2005
- 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
SIST-TS TS 101 191 V1.4.1:2005 is the Slovenian version of ETSI TS 101 191 V1.4.1, published by SIST. It specifies a DVB mega-frame and a Mega-frame Initialization Packet (MIP) for Single Frequency Network (SFN) synchronization, with optional control of transmitter and modulator parameters. The Slovenian page presents it as an update to an existing specification that incorporates elements of DVB-H.
What does SIST-TS TS 101 191 V1.4.1:2005 specify?
SIST-TS TS 101 191 V1.4.1:2005 specifies the structure and use of a mega-frame, including the MIP, for SFN synchronization in DVB systems. It also covers optional control of other important SFN parameters, so implementers can use one signaling mechanism for timing and selected transmitter settings.
The document treats SFN functionality as an extension to the DVB system. The SFN adapter, SYNC system and MIP-based control are described as additional elements for SFN use and not necessary in MFN applications.
The document is organized into these main clauses and normative annexes:
| Part | What it covers |
|---|---|
| Clause 1 | Scope |
| Clause 2 | References |
| Clause 3 | Definitions and abbreviations |
| Clause 4 | General description of the SFN system |
| Clause 5 | Mega-frame definition |
| Clause 6 | MIP structure and functions |
| 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 V1.4.1:2005?
The central requirement is that the SFN adapter output shall be a valid MPEG-2 TS, and that the stream is organized into mega-frames with one MIP in each mega-frame. In practice, this means the synchronization information travels inside normal transport packets, not as a separate side channel.
Mega-frame structure and timing
A mega-frame contains an integer number of TS packets, and the packet count depends on the DVB-T mode used for emission. Clause 5 ties the mega-frame start to the beginning of a DVB-T super-frame and the start of an inverted sync byte, which gives all sites a common frame reference.
Clause 4 states that the MIP carries a Synchronization Time Stamp (STS), derived from a 1 pps reference such as GPS. The SYNC system compares the STS with the local time reference to calculate the extra delay needed for SFN synchronization, so the transmitter site can line up its output with the network timing.
Clause 4 also states that the maximum network delay the SYNC system can handle is 1 s. That matters when planning the primary distribution network, because the end-to-end delay budget must stay within what the synchronization method can compensate.
MIP format and coding
Clause 6 defines the MIP as an MPEG-2 compliant TS packet with a fixed length of 188 bytes. The packet header uses PID 0x15, scrambling is disabled, and the adaptation field is not used. For implementation, this means the MIP must fit cleanly into a standard transport stream packet structure.
The MIP fields include synchronization_id, section_length, pointer, periodic_flag, STS, maximum_delay, tps_mip and an optional individual addressing section. The pointer identifies the first packet of the following mega-frame, while periodic_flag tells the receiver whether insertion is periodic or aperiodic. Systems that use this document shall handle both insertion modes.
The synchronization_time_stamp and maximum_delay fields are both expressed in 100 ns steps. maximum_delay shall cover the longest delay in the primary distribution network plus the delays in modulators, power transmitters and antenna feeders. In practice, this is the field that tells the site how much timing offset it must absorb.
MIP functions for transmitter control
Clause 6.1 defines optional functions carried by the MIP. These include transmitter time offset, transmitter frequency offset, transmitter power, private data, cell id, enable and bandwidth. The functions are optional, but they give operators a single place to signal coordinated changes to SFN sites.
The transmitter time offset function sets a deliberate timing shift, the frequency offset function sets a deliberate RF frequency shift, and the power function configures ERP. The cell id function can update the transmitter cell identifier, and the enable function is used to execute previously signaled changes. The bandwidth function can signal channel bandwidth values outside 6 MHz, 7 MHz and 8 MHz.
Modulator reconfiguration
Annex C explains how tps_mip is used to reconfigure DVB-T modulator parameters. It sets out the timing relationship between the MIP content and the update of TPS data and new modulator configuration, so operators can plan changes without ambiguity.
What terms does SIST-TS TS 101 191 V1.4.1:2005 define?
- Single Frequency Network (SFN): A DVB network in which transmitters are synchronized to work together on the same frequency.
- Mega-frame Initialization Packet (MIP): The TS packet that carries SFN synchronization and optional control information.
- Synchronization Time Stamp (STS): The time difference between the latest 1 pps reference and the start of the next mega-frame.
- Transport Stream (TS): The MPEG-2 packet stream used as the transport format in this document.
- Transport Parameter Signalling (TPS): DVB-T signaling information referenced in tps_mip and used for modulator reconfiguration.
- Effective Radiated Power (ERP): The transmitter power value controlled by the tx_power function.
- Global Positioning System (GPS): A possible time reference that can provide 10 MHz and 1 pps signals.
Who uses SIST-TS TS 101 191 V1.4.1:2005?
This standard is used by broadcast engineers, SFN planners, transmitter manufacturers, multiplex operators and network integrators working with DVB-T distribution. It matters when they design the primary distribution network, synchronize sites, set timing and frequency offsets, configure ERP, or coordinate modulator changes across several transmitters.
Quality and compliance teams use it to check that the transport stream, packet structure and MIP signaling match the expected SFN behavior. It is also relevant in digital television projects where multiple transmitters must emit bit-identical streams with aligned timing.
Which standards are used with SIST-TS TS 101 191 V1.4.1:2005?
- ISO/IEC 13818-1 - supplies the MPEG-2 Systems rules for the transport packet header used by the MIP.
- ETSI EN 300 744 - provides the DVB-T framing structure, channel coding and modulation context, including DVB-T frame and super-frame references.
- ETSI EN 300 468 - provides Service Information definitions, including the cell term used by the cell_id function.
What does the SIST-TS TS 101 191 V1.4.1:2005 document contain?
The document contains the general SFN system description, the mega-frame definition, the detailed MIP field layout, and the optional function formats. It also includes a table of mega-frame durations for different channel bandwidths and guard intervals, which is useful when setting timing budgets.
Annex A gives the CRC decoder model used for MIP verification. Annex B explains the synchronization process with a time diagram. Annex C gives the timing and update sequence for reconfiguring DVB-T modulator parameters by using the MIP, which is useful for implementation and conformance checking.
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Frequently Asked Questions
SIST-TS TS 101 191 V1.4.1:2005 is a technical specification published by the Slovenian Institute for Standardization (SIST). Its full title is "Digital Video Broadcasting (DVB); DVB mega-frame for Single Frequency Network (SFN) synchronization". This standard covers: Update to existing specification to incorporate elements of DVB-H
Update to existing specification to incorporate elements of DVB-H
SIST-TS TS 101 191 V1.4.1:2005 is classified under the following ICS (International Classification for Standards) categories: 33.170 - Television and radio broadcasting. The ICS classification helps identify the subject area and facilitates finding related standards.
SIST-TS TS 101 191 V1.4.1:2005 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
SLOVENSKI STANDARD
01-november-2005
'LJLWDOQDYLGHRUDGLRGLIX]LMD '9% ±0HJDVWUXNWXUD'9%]DVLQKURQL]DFLMR
HQRIUHNYHQþQLKRPUHåLM 6)1
Digital Video Broadcasting (DVB); DVB mega-frame for Single Frequency Network (SFN)
synchronization
Ta slovenski standard je istoveten z: TS 101 191 Version 1.4.1
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.
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
2 ETSI TS 101 191 V1.4.1 (2004-06)
Reference
RTS/JTC-DVB-164
Keywords
broadcasting, digital, DVB, TV, video
ETSI
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ETSI
3 ETSI TS 101 191 V1.4.1 (2004-06)
Contents
Intellectual Property Rights.4
Foreword.4
1 Scope.5
2 References.5
3 Definitions and abbreviations.5
3.1 Definitions.5
3.2 Abbreviations.5
4 General description.6
5 Mega-frame definition.8
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 function.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 synchronization.16
Annex C (normative): Reconfiguration of DVB-T modulator parameters by using the MIP .17
History .18
ETSI
4 ETSI TS 101 191 V1.4.1 (2004-06)
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 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/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 the present document.
Foreword
This Technical Specification (TS) has been produced by Joint Technical Committee (JTC) Broadcast of the European
Broadcasting Union (EBU), Comité Européen de Normalisation ELECtrotechnique (CENELEC) and the European
Telecommunications Standards Institute (ETSI).
NOTE: 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
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: +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 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 the consumer electronics and the
broadcast industry.
ETSI
5 ETSI TS 101 191 V1.4.1 (2004-06)
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 control 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
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 to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
[1] ISO/IEC 13818-1 (1994): "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); Specification 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 [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 Priority
MFN Multi Frequency Network
MIP Mega-frame Initialization Packet
MPEG Moving Pictures Expert Group
ETSI
6 ETSI TS 101 191 V1.4.1 (2004-06)
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 Synchronization Time Stamp
SYNC SYNChronization
TPH Transport Packet Header
TPS Transport Parameter Signalling
TS Transport Stream
TX Transmitter
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
Network GPS (note)
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 SI and provides
an MPEG-2 TS, which, after SFN adaptation, is transmitted via the DVB-T modulators in the SFN.
ETSI
7 ETSI TS 101 191 V1.4.1 (2004-06)
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 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, MIP , allows to uniquely identify the starting
M
point (i.e. the first packet) of the mega-frame M+1. This is accomplished by using a pointer carried by the MIP itself
M
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 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 only dependent on the channel bandwidth and the guard interval proportion,
i.e. the mega-frame duration is independent of the duration T , constellation and code rate of the DVB-T signal. The
U
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: Mega-frame duration for all combinations of channel bandwidth
and guard interval proportions
Channel bandwidth
Guard Interval 8 MHz 7 MHz 6 MHz 5 MHz
Δ / T = 1/32 0,5026560 s 0,5744640 s 0,6702080 s 0,8042496 s
U
Δ / T = 1/16 0,5178880 s 0,5918720 s 0,6905173 s 0,8286208 s
U
Δ / T = 1/8 0,5483520 s 0,6266880 s 0,7311360 s 0,8773632 s
U
Δ / T = 1/4 0,6092800 s 0,6963200 s 0,8123733 s 0,9748480 s
U
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 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 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 (1 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
MFN applications.
ETSI
8 ETSI TS 101 191 V1.4.1 (2004-06)
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 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], 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 contains 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 positioning of the MIP, is
given. The exact definition of the MIP format is given in clause 6.
Mega-frame
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.
Figure 2: Overall mega-frame structure
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 trans
...