Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 1Rev -, July 2001
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 2Rev -, July 2001
Introduction to DVBDVB stands for Digital Video Broadcasting.
DVB is the most used transport stream standard for the distribution of digital video material over satellite and cable.
At the end of 1991, a consortium of European broadcasters, manufacturers, public and private media groups, and regulatory bodies came together to form the European Launching Group (ELG). The ELG was tasked to develop a digital terrestrial TV standard.
In September 1993 a Memorandum of Understanding (MOU) was signed by all members of the ELG. The MOU established the rules by which the members would work together to develop the new standard.
Once the MOU was signed, the ELG became the DVB group.
Vol 6: Digital Video
Sec 5: Digital Video Broadcasting
6.5.1: Introduction to DVB
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 3Rev -, July 2001
Introduction to DVBThe DVB consortium now comprises over 225 organizations from more than 30 countries around the world.
While DVB was being defined in Europe, a similar program was taken place in the US (ATSC), driven by an advisory committee of the United States Federal Communications Commission (FCC).
The DVB standard was from the start intended to define an internationally accepted standard for the distribution of digital television programming.
ATSC’s main goal was to provide a guideline to the FCC to define a US Standard for the distribution of digital television.
Vol 6: Digital Video
Sec 5: Digital Video Broadcasting
6.5.1: Introduction to DVB
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 4Rev -, July 2001
Introduction to DVB The DVB consortium did not define a new standard for the compression of audio or video programs. Instead, it opted to use the MPEG 2 standard.
The DVB standard defines the rules regarding framing structure, channel coding, modulation scheme, and the service information table (SIT), and it provide some guidelines for the implementation of a common conditional access system.
The first standard issued by the DVB consortium defines the distribution of digital programming over satellite using the QPSK modulation scheme. This standard was issue at the end of 1993. The second major standard was one defining cable distribution using 64QAM (1994). A terrestrial distribution standard was issued in 1996.
Vol 6: Digital Video
Sec 5: Digital Video Broadcasting
6.5.1: Introduction to DVB
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 5Rev -, July 2001
Introduction to DVBThe most important DVB standards are:
Framing structure, channel coding and modulation DVB-S Satellite SystemsDVB-C Cable SystemsDVB-T Digital Terrestrial SystemsDVB-MT Microwave Digital Terrestrial Systems
Conditional AccessDVB-CA Conditional Access SystemDVB-CS Common Scrambling System
OtherDVB-SI Service Information SystemDVB-VBI VBI informationDVB-Data Data Information
Vol 6: Digital Video
Sec 5: Digital Video Broadcasting
6.5.1: Introduction to DVB
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 6Rev -, July 2001
Philosophy of the DVB ConsortiumThe DVB consortium’s philosophy is based on the following four factors:
Open System: The standards are available worldwide to anyone for a nominal cost.
Interoperable: Equipment that complies to the DVB standard is fully compatible with other DVB-compliant equipment built by another manufacturer.
Flexible: Supports various video formats (PAL, NTSC, SECAM, HDTV), audio, data signals. It will also support multimedia data and interactive services.
Market-led: This is not a government driven standard. The standard was developed for manufacturers and users of the technology by manufacturing and user groups.
Vol 6: Digital Video
Sec 5: Digital Video Broadcasting
6.5.2: Philosophy of the DVB Consortium
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 7Rev -, July 2001
MPEG 2 SystemThe DVB standard supports the MPEG 2 PSI tables
Program Association Table (PAT),
Program Map Table (PMT)
Conditional Access Table (CAT).
The DVB standard defines its own Network Information Table (NIT) based on the recommendations from the MPEG group. The specification for the NIT will be discussed in a later part of this section dealing with the DVB SI table.
The standard supports four different video formats and three aspect ratios. The standard supports MPEG 2 layer II audio.
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 3: MPEG 2 Standard
6.5.3.1: MPEG 2 System
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 8Rev -, July 2001
Program Associated Table (PAT)The PAT is used to indicate the Packet Identifier (PID) value for each program or SI table within the the MPEG transport stream. The PAT provides the PID value for the PMT associated with each program.
The PID value is used by the decoder to sort the different packets so that it can later regroup those with similar PID’s to recreate the original program elementary stream (PES).
The PAT is always set with PID 0x0000.
DVB recommends that the PAT should be transmitted at an interval equal to or less than 100 milliseconds.
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 3: MPEG 2 Standard
6.5.3.1: MPEG 2 System
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 9Rev -, July 2001
Figure 6.5.3.1a Relation Between PAT, PMT, CAT and NIT
P A T P M T0x0036
PID 0x0036
PID 0x0037 P M T0x0037
C A T0x0001
N IT0x0010
V ideo0x1420
A ud io0x1430
V ideo0x155 0
A ud io0x156 0
A ud io0x157 0
PID 0x0001
PID 0x0010
PID 0x1420
PID 0x1430
PID 0x1550
PID 0x1560
PID 0x1570
Pro gram 1
Pro gram 2
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 3: MPEG 2 Standard
6.5.3.1: MPEG 2 System
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 10Rev -, July 2001
Program Associated Table (PAT)Table ID assignment0x00 PAT0x01 CAT0x02 program map section0x03 transport stream description0x40 network info (actual network)0x41 network info (other network)0x42 service description section (actual
transport stream)0x46 service description section(other
transport stream)0x4A bouquet association section0x4E event information section (actual
transport stream, present/following)
Program Association Table 0x0000
O ne loopper
program
table ID 0x00
section syntax indicator
8
1
zero 1
reserved 2
section length 12
transport stream ID 16
reserved 2
version num ber 5
current next indicator 1
section number 8
last section num ber 8
program zero 16
reserved 3
program num ber 3
reserved 13
program m ap PID 5
netw ork PID 13
CRC 32 32
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 3: MPEG 2 Standard
6.5.3.1: MPEG 2 SystemFigure 6.5.3.1ba P
rogram A
ssociated Table (PA
T)
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 11Rev -, July 2001
Program Associated Table (PAT)Table ID assignment0x004F event information table (other
transport stream, present-following)
0x0070 time date section0x0071 running status section0x0072 stuffing section0x0073 time offset section0x007E discontinuity information section0x007F selection information section
Program Association Table 0x0000
O ne loopper
program
table ID 0x00
section syntax indicator
8
1
zero 1
reserved 2
section length 12
transport stream ID 16
reserved 2
version num ber 5
current next indicator 1
section number 8
last section num ber 8
program zero 16
reserved 3
program num ber 3
reserved 13
program m ap PID 5
netw ork PID 13
CRC 32 32
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 3: MPEG 2 Standard
6.5.3.1: MPEG 2 SystemFigure 6.5.3.1bb P
rogram A
ssociated Table (PA
T)
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 12Rev -, July 2001
Program Map Table (PMT)One PMT per program or service. Each PMT is assigned a PID by the compression system.
Table ID 0x02.
The PMT is used to identify the PID of each PES found in this service. It is also used to identify the corresponding Program Clock Reference (PCR) for this service.
Program M ap Table (PID assigned)
One loopper
elem entarystream
table ID 0x02
section syntax indicator
8
1
zero 1
reserved 2
section length 12
program num ber 16
reserved 2
version num ber 5
current next indicator 1
section num ber 8
last section num ber 8
PCR PID 13
reserved 4
descriptor
reserved 8
stream type 3
program info length 12
CRC 32 32
reserved 3
reserved 13
elem entary PID 4
reserved 12
descriptor
ES info length 5
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 3: MPEG 2 Standard
6.5.3.1: MPEG 2 SystemFigure 6.5.3.1ca P
rogram M
ap Table (PM
T)
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 13Rev -, July 2001
Program Map Table (PMT)A program could consist of one video PES and the audio PES associated with the video.
This program would be assigned one PMT which would direct the decoder to the PID associated to that video and audio PES.
Another program could consist of the same video PES and another audio PES (another language) associated with the video.
A different PMT would be used for this program.
Program M ap Table (P ID assigned)
One loopper
elem en tarystream
tab le ID 0x02
section syntax indicator
8
1
zero 1
reserved 2
section leng th 12
program num ber 16
reserved 2
version number 5
current next ind icator 1
section num ber 8
last section num ber 8
PC R PID 13
reserved 4
descriptor
reserved 8
stream type 3
program info length 12
CRC 32 32
reserved 3
reserved 13
elem entary PID 4
reserved 12
descriptor
ES info length 5
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 3: MPEG 2 Standard
6.5.3.1: MPEG 2 SystemFigure 6.5.3.1cb P
rogram M
ap Table (PM
T)
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 14Rev -, July 2001
PAT PM T0x0036
PID 0x0036
PID 0x0037 PM T0x0037
C AT0x0001
N IT0x0010
V ide o0x1420
A ud io0x1430
V ideo0x1550
A ud io0x1560
A ud io0x1570
PID 0x0001
PID 0x0010
PID 0x1420
PID 0x1430
PID 0x1550
PID 0x1560
PID 0x1570
Pro gram 1
Program 2
PM T0x0038
V ideo0x1 420
A ud io0x1 440
PID 0x1420
PID 0x1440
Pro gram 3
PID 0x0038
PID 0x1420is present in
program 1 and 3
Figure 6.5.3.1d P MT Table when Sharing Two Video PES’s between Three Programs
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 3: MPEG 2 Standard
6.5.3.1: MPEG 2 System
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 15Rev -, July 2001
Program Map Table (PMT)PMT descriptor and their tag valueVideo stream 0x02 Copyright0x0DAudio stream 0x03 Maximum bitrate 0x0EHierarchy 0x04 Private data indicator 0x0FRegistration 0x05 Smoothing buffer0x10Data stream alignment 0x06 STD0x11Target background grid 0x07 IBP0x12Video window 0x08 User private0x14CA 0x09 Mosaic0x51ISO 639 language 0x0A Stream identifier0x52System clock 0x0B Teletext0x56Multiplex buffer utilization 0x0C Subtitling0x59
Service move0x60
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 3: MPEG 2 Standard
6.5.3.1: MPEG 2 System
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 16Rev -, July 2001
Conditional Access Table (CAT)PID address set to 0x0001.
Table ID 0x01.
The CAT provides information on the conditional access system used within this multiplex (if any).
The specific information for the CA system is proprietary to the manufacturer and hence not readily available.
The CAT must indicate the location of the EMM (Entitlement Management Message).
Conditional Access Table 0x0001
table ID 0x01
section syntax indicator
8
1
zero 1
reserved 2
section length 12
reserved 18
reserved 2
version num ber 5
current next ind icator 1
section num ber 8
last section num ber 8
descrip tor
CR C 32 32
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 3: MPEG 2 Standard
6.5.3.1: MPEG 2 System
Figure 6.5.3.1e Conditional Access Table (CAT)
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 17Rev -, July 2001 Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 3: MPEG 2 Standard
6.5.3.2: Video
Figure 6.5.3.2 MPEG-2 Profiles and Levels
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 18Rev -, July 2001
VideoDVB adopted the MPEG 2 standard, but has put some restrictions on, and additions to, that standard.
The DVB standards state that the system shall comply with the following profiles and levels:
Standard Definition Television (SDTV)
• Main Profile and Main Level
High Definition Television (HDTV)
• Main Profile and High Level
The system can also operate at one of the other profiles or levels. The DVB standard supports 25 and 30 Hz SDTV or HDTV systems.
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 3: MPEG 2 Standard
6.5.3.2: Video
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 19Rev -, July 2001
VideoThe DVB standard specifies that compliant systems will at least support the following aspect ratios:
4:3 (standard home television format)
16:9 (wide television format)
2.21:1 (35 mm film format… this aspect ratio is only an option with SDTV systems)
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 3: MPEG 2 Standard
6.5.3.2: Video
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 20Rev -, July 2001
VideoA DVB compliant system shall support a least the following luminance resolutions (horizontal x vertical) for a full screen picture:
25 Hz SDTV 30 Hz SDTV
720 x 576 720 x 480
544 x 576 640 x 480
480 x 576 544 x 480
352 x 576 480 x 480
352 x 288 352 x 480
352 x 240
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 3: MPEG 2 Standard
6.5.3.2: Video
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 21Rev -, July 2001
VideoThe DVB standard specifies that the luminance resolution for a 25 and 30 Hz HDTV signal shall not exceed:
• 1152 lines per frame
• 1920 luminance samples per line
The DVB standard recommends that a 25 and 30 Hz HDTV bitstream have a luminance resolution for one picture frame of:
• 1080 lines per frame
• 1920 luminance samples per line with an associated frame rate of 25 Hz or 29.97 Hz with two interlaced fields per frame
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 3: MPEG 2 Standard
6.5.3.2: Video
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 22Rev -, July 2001
AudioThe DVB standard supports the MPEG 2 Audio Layer II standards. Compliance with MPEG 2 Audio Layer III is optional, not mandatory.
The minimum audio requirements specified in the DVB standard are:
MPEG 1 single channel
MPEG 1 dual channel
MPEG 1 joint stereo
MPEG 1 stereo
MPEG 2 multi-channel audio, backward compatible to MPEG 1 (mandatory for encoders, but not for integrated receiver decoders (IRD))
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 3: MPEG 2 Standard
6.5.3.3: Audio
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 23Rev -, July 2001
AudioThe audio will support the following sampling rates:
32 kHz, 44.1 kHz and 48 kHz
Support for the following sampling rates is optional:
16 kHz, 22.05 kHz and 24 kHz
The following bit rates are supported:
Layer I 32, 64, 96, 128, 160, 192, 224, 256, 288, 320, 352, 384, 416 or 448 kbps
Layer II 32, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, or 384 kbps
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 3: MPEG 2 Standard
6.5.3.3: Audio
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 24Rev -, July 2001
PM TProgram n
PATPID 0x0000
CATPID 0x0001
PM TProgram 2
PM TProgram 1
M PEG PSI DVB M andatory S I Tables
NITPID 0x0010(Actual TS)
PID forPM T is
Assigned
SDTPID 0x0011(Actual TS)
EITPID 0x0012(Actual TS
present/fo llow ing)
TDTPID 0x0014
(T im e and Date)
DVB Optional S I Tables
NITPID 0x0010(O ther TS)
SDTPID 0x0011(O ther TS)
EITPID 0x0012(O ther TS
present/fo llow ing)
RSTPID 0x0013
BATPID 0x0011
EITPID 0x0012(Actu al TSschedule)
EITPID 0x0012(O ther TSschedu le)
TOTPID 0x0014
STPID 0x0010 to
PID 0x0014
Vol 6: Digital Video
Sec 5: Digital Video Broadcasting
6.5.4: DVB SI Tables
Figure 6.5.4 DVB SI Tables
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 25Rev -, July 2001
DVB Mandatory SI TablesFor a system to be DVB compliant it must support the following SI tables:
PAT - Program Association Table (MPEG)
CAT - Conditional Access Table (MPEG)
PMT - Program Map Table (MPEG)
NIT - Network Information Table (DVB)
SDT - Service Description Table (DVB)
EIT -Event Information Table (DVB)
TDT - Time and Date Table (DVB)
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 4: DVB SI Tables
6.5.4.1: DVB Mandatory SI Tables
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 26Rev -, July 2001
Network Information Table (NIT)PID address set to 0x0010.
Table ID 0x40 (actual network.)
Table ID 0x41 (other network-optional.)
The NIT provides information on a group of programs or transport streams. The NIT is used to provide information on the system used to deliver the data stream.
More than one NIT can be identified per system. This can be useful when you need to identify a present and past network (e.g. combining service from two networks in a new system.)
Network Information Table 0x0010
table ID (refer to text)
section syntax indicator
8
1
reserved for future use 1
reserved 2
section length 12
transport stream ID 16
reserved 2
version number 5
current next indicator 1
section number 8
last section number 8
reserved for future use 16
network descriptors length 12
transport stream ID 3
original network ID 13
reserved future use 5
transport stream loop length 12
CRC 32 32
descriptor
reserved for future use 4
transp. descrip. length 13
descriptor
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 4: DVB SI Tables
6.5.4.1: DVB Mandatory SI Tables
Figure 6.5.4.1aa Netw
ork Information Table (N
IT)
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 27Rev -, July 2001 Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 4: DVB SI Tables
6.5.4.1: DVB Mandatory SI Tables
Figure 6.5.4.1b Example: Combining Two Transport Streams in a New Transport Stream
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 28Rev -, July 2001
Network Information Table (NIT)The NIT can be used to identify whether the delivery system is for satellite or cable media. A satellite IRD will disregard the incoming transport stream if the NIT identifies the transport stream as being delivered by a system other than a satellite system (e.g. a cable system).
The NIT can be used to link the information from several satellite services as if they were one system. The NIT enables the sharing of information such as the Electronic Program Guide (EPG) of a Direct to Home (DTH) system.
N etw ork In form ation Table 0x0010
table ID (re fer to text)
section syntax indicator
8
1
reserved for fu ture use 1
reserved 2
section leng th 12
transport stream ID 16
reserved 2
version number 5
current next ind icator 1
section num ber 8
last section num ber 8
reserved for fu ture use 16
netw ork descrip tors length 12
transport stream ID 3
orig ina l netw ork ID 13
reserved fu ture use 5
transport stream loop leng th 12
C RC 32 32
descriptor
reserved for fu ture use 4
transp. descrip. length 13
descriptor
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 4: DVB SI Tables
6.5.4.1: DVB Mandatory SI Tables
Figure 6.5.4.1ab Netw
ork Information Table (N
IT)
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 29Rev -, July 2001
Network Information Table (NIT)NIT Descriptors:Network name 0x40
Service list 0x41
Stuffing 0x42
Satellite delivery system 0x43
Cable delivery system 0x44
Linkage 0x4A
Terrestrial delivery system 0x5A
Multilingual network name 0x5B
Private data specifier 0x5F
N etw ork In form ation Table 0x0010
table ID (re fer to text)
section syntax indicator
8
1
reserved for fu ture use 1
reserved 2
section leng th 12
transport stream ID 16
reserved 2
version number 5
current next ind icator 1
section num ber 8
last section num ber 8
reserved for fu ture use 16
netw ork descrip tors length 12
transport stream ID 3
orig ina l netw ork ID 13
reserved fu ture use 5
transport stream loop leng th 12
C RC 32 32
descriptor
reserved for fu ture use 4
transp. descrip. length 13
descriptor
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 4: DVB SI Tables
6.5.4.1: DVB Mandatory SI Tables
Figure 6.5.4.1ac Netw
ork Information Table (N
IT)
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 30Rev -, July 2001
Service Description Table (SDT)PID address set to 0x0011
Table ID 0x40 (actual stream)
Table ID 0x41 (other stream-optional)
Each transport stream is assigned a SDT sub-table.
Service Description Table 0x0011
table ID (refer to text)
section syntax indicator
8
1
reserve fo r future use 1
reserved 2
section length 12
transport stream ID 16
reserved 2
version num ber 5
current next ind icator 1
section num ber 8
last section num ber 8
orig ina l network ID 16
reserved for future use 8
reserved future use 6
EIT schedule flag 1
descrip tor
service ID 16
C RC 32 32
EIT pres/foll flag 1
running status 3
free CA m ode 1
descrip tor loop length 12
pres/foll = p resent fo llow ing
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 4: DVB SI Tables
6.5.4.1: DVB Mandatory SI Tables
Figure 6.5.4.1ca Service Description Table (SDT)
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 31Rev -, July 2001
Service Description Table (SDT)The SDT is used to provide information on the following parameters:
• Service name
• Service provider
• Presence of EIT schedule for service
• Scrambling ON/OFF• Name of the bouquet service
(grouping of services)• Linkage to a network or system
(e.g. DirectTV)
Service Description Tab le 0x0011
table ID (refer to text)
section syntax indicator
8
1
reserve for fu ture use 1
reserved 2
section length 12
transport stream ID 16
reserved 2
version num ber 5
current next indicator 1
section num ber 8
last section num ber 8
original netw ork ID 16
reserved for future use 8
reserved future use 6
E IT schedule flag 1
descrip tor
service ID 16
C RC 32 32
E IT pres/fo ll flag 1
runn ing status 3
free CA m ode 1
descriptor loop length 12
pres/fo ll = p resent fo llow ing
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 4: DVB SI Tables
6.5.4.1: DVB Mandatory SI Tables
Figure 6.5.4.1cb Service Description Table (SDT)
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 32Rev -, July 2001
Service Description Table (SDT)SDT DescriptorsStuffing 0x42Bouquet name 0x47Service 0x48Country availability 0x49Linkage 0x4ANVOD reference 0x4BTime shifted service 0x4CMosaic 0x51CA identifier 0x53Telephone 0x57Multilingual service name 0x5DPrivate data specifier 0x5F
Service Description Tab le 0x0011
table ID (refer to text)
section syntax indicator
8
1
reserve for fu ture use 1
reserved 2
section length 12
transport stream ID 16
reserved 2
version num ber 5
current next indicator 1
section num ber 8
last section num ber 8
original netw ork ID 16
reserved for future use 8
reserved future use 6
E IT schedule flag 1
descrip tor
service ID 16
C RC 32 32
E IT pres/fo ll flag 1
runn ing status 3
free CA m ode 1
descriptor loop length 12
pres/fo ll = p resent fo llow ing
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 4: DVB SI Tables
6.5.4.1: DVB Mandatory SI Tables
Figure 6.5.4.1cc Service Description Table (SDT)
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 33Rev -, July 2001
Event Information Table (EIT)PID address set to 0x0012
• Table ID 0x4E (actual stream, present/following)
• Table ID 0x4F (other stream, present/following)
• Table ID 0x50-0x5F (actual stream, schedule)
• Table ID 0x60-0x6F (other stream, schedule)
The EIT is used to transmit information about the services provided by the different programs within the multiplex.
Event In form ation Table 0x0012
table ID (refer to text)
section syntax indicator
8
1
reserve for future use 1
reserved 2
section length 12
service ID 16
reserved 2
version num ber 5
current next ind icator 1
section number 8
last section num ber 8
transport stream ID 16
orig ina l netw ork ID 16
start tim e 6
dura tion 1
descrip tor
event ID 16
C RC 32 32
runn ing status 1
free C A m ode 1
descriptor loop leng th 12
segm ent last section no 8
last tab le ID 8
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 4: DVB SI Tables
6.5.4.1: DVB Mandatory SI Tables
Figure 6.5.4.1da Event Inform
ation Table (EIT)
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 34Rev -, July 2001
Event Information Table (EIT)The EIT provides information on the present service (e.g. “S.L. CHI”), next service (e.g. “JADAL”) and future service (e.g. “American Movie”) for each program. In this example the program would consist of the video and audio PES for MTV, Arabsat 3A, Fourth Bouquet.
Example:Present service S.L. CHI
(20:30 to 21:30)
Following service JADAL
(21:30 to 23:30)
Future service American Movie
(23:30 to 01:30)
Event In form ation Table 0x0012
table ID (refer to text)
section syntax indicator
8
1
reserve for future use 1
reserved 2
section length 12
service ID 16
reserved 2
version num ber 5
current next ind icator 1
section number 8
last section num ber 8
transport stream ID 16
orig ina l netw ork ID 16
start tim e 6
dura tion 1
descrip tor
event ID 16
C RC 32 32
runn ing status 1
free C A m ode 1
descriptor loop leng th 12
segm ent last section no 8
last tab le ID 8
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 4: DVB SI Tables
6.5.4.1: DVB Mandatory SI Tables
Figure 6.5.4.1db Event Inform
ation Table (EIT)
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 35Rev -, July 2001
Event Information Table (EIT)EIT DescriptorsStuffing 0x42Linkage 0x4AShort event 0x4DExtended event 0x4ETime shifted event 0x4FComponent descriptor 0x50CA identifier 0x53Content 0x54Parental rating 0x55Telephone 0x57Multilingual component 0x5EPrivate data specifier 0x5FShort smoothing buffer 0x61
Event In form ation Table 0x0012
table ID (refer to text)
section syntax indicator
8
1
reserve for future use 1
reserved 2
section length 12
service ID 16
reserved 2
version num ber 5
current next ind icator 1
section number 8
last section num ber 8
transport stream ID 16
orig ina l netw ork ID 16
start tim e 6
dura tion 1
descrip tor
event ID 16
C RC 32 32
runn ing status 1
free C A m ode 1
descriptor loop leng th 12
segm ent last section no 8
last tab le ID 8
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 4: DVB SI Tables
6.5.4.1: DVB Mandatory SI Tables
Figure 6.5.4.1dc Event Inform
ation Table (EIT)
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 36Rev -, July 2001
Time and Date Table (TDT)PID address set to 0x0014
Table ID 0x70
The TDT is used to transmit the actual UTC time. The time is coded as a modified Julian Date (MJD).
The IRD may use the TDT to synchronize internal clocks. The TDT is transmitted at least every 30 seconds.
Tim e and D ate Table 0x0014
table ID 0x70
section syntax indicator
8
1
reserve for future use 1
reserved 2
section length 12
U TC tim e 40
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 4: DVB SI Tables
6.5.4.1: DVB Mandatory SI Tables
Figure 6.5.4.1e Time and Date Table (TDT)
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 37Rev -, July 2001
DVB Optional SI TableThe DVB standard also defines the usage of other SI tables that are not required for DVB compliance. The implementation of these tables is left to the manufacturers discretion and may or may not be required, depending on the application for the multiplex system.
NIT - Network Information Table (other network)
SDT - Service Description Table (other stream)
EIT - Event Information Table (other stream)
BAT - Bouquet Association Table
RST - Running Status Table
ST - Stuffing Table
TOT - Time Offset TableVol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 4: DVB SI Tables
6.5.4.2: DVB Optional SI Tables
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 38Rev -, July 2001
Optional NIT, SDT and EIT TablesPID address 0x0010 for NIT
0x0011 for SDT
0x0012 for EIT
Table ID 0x41 for NIT (other network)
0x41 for SDT (other stream)
0x4F for EIT (other stream, present/following)
0x4F for EIT (other stream, schedule)
The optional NIT, SDT and EIT tables use the same framing structure explained in the previous sections.
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 4: DVB SI Tables
6.5.4.2: DVB Optional SI Tables
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 39Rev -, July 2001
Optional NIT, SDT and EIT TablesThe NIT can be used to provide information on the network from which a transport stream originated. The implementation of the NIT for other networks is optional. The implementation of the NIT for the actual network is mandatory.
The optional SDT table provides information on streams from another mutliplex. Depending on the way this table is implemented, the optional SDT table can reduce the access time of a consumer IRD (e.g. DTH application) seeking obtain service information from another multiplex.
The implementation of the SDT for other stream is optional. The implementation of the SDT for the actual stream is mandatory.
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 4: DVB SI Tables
6.5.4.2: DVB Optional SI Tables
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 40Rev -, July 2001
Optional NIT, SDT and EIT TablesThe EIT optional table provides present/following and scheduling information for content located on another stream. This, then, allows the sharing of information between streams, which in turn reduces the acquisition time for this information within IRDs.
The implementation of the EIT for other streams is optional. The implementation of the EIT for the actual stream is mandatory.
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 4: DVB SI Tables
6.5.4.2: DVB Optional SI Tables
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 41Rev -, July 2001
Bouquet Association Table (BAT)PID address set to 0x0011
Table ID 0x4A
The BAT is an optional table. The BAT is used to group several services together. The services under a BAT could be common to several networks. Several bouquets could be found within the same network.
The BAT could be used to group television programs from the same provider that are distributed on a different multiplex on the same satellite.
Bouquet Association Table 0x0011
table ID 0x4A
section syntax indicator
8
1
reserve for future use 1
reserved 2
section length 12
bouquet ID 16
reserved 2
version num ber 5
current next indicator 1
section num ber 8
last section num ber 8
reserved for future use 4
reserved fu ture use 4
transport stream loop length 12
TS descr length
bouquest descrip tors length 12
CRC 32 32
transport stream ID 16
original network ID 16
reserved fu ture use 4
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 4: DVB SI Tables
6.5.4.2: DVB Optional SI Tables
Figure 6.5.4.2a Bouquet A
ssociation Table (BA
T)
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 42Rev -, July 2001
Running Status Table (RST)PID address set to 0x0013
Table ID 0x71
The RST provides a means by which the IRDs or VCRs can perform a very accurate switching (e.g. VCR recording) at the start of an event. This is done by setting the equipment to detect the RST command and then waiting for the table to be received.
The running status table is not transmitted in a continuous fashion. It is transmitted at predetermined times for the control of the IRDs or VCRs.
R unning Status Table 0x0013
table ID 0x71
section syntax indicator
8
1
reserve for future use 1
reserved 2
section length 12
runn ing status
service ID 16
event ID 16
reserved future use 4
transport stream ID 16
orig inal network ID 16
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 4: DVB SI Tables
6.5.4.2: DVB Optional SI Tables
Figure 6.5.4.2b Running Status Table (RST)
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 43Rev -, July 2001
Stuffing Table (ST)PID address set to 0x0013
Table ID 0x72
The ST table is an optional table. It is used to authorize the replacement of complete SI tables.
This is sometime required to remove invalid tables that are not required by specific delivery systems.
Stuffing Table
table ID 0x72
section syntax indicator
8
1
reserve for future use 1
reserved 2
section length 12
data byte 8
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 4: DVB SI Tables
6.5.4.2: DVB Optional SI Tables
Figure 6.5.4.2c Stuffing Table (ST)
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 44Rev -, July 2001
Time Offset Table (TOT)PID address set to 0x0014
Table ID 0x73
The TOT table is used to supply the UTC time/date. It also provides the difference between that time and the local time.
The TOT can provide the difference between UTC and local time for several geographical regions.
Tim e O ffset Table 0x0014
tab le ID 0x73
section syntax indicator
8
1
reserve for future use 1
reserved 2
section length 12
descriptor
C RC 32 32
U TC tim e 40
reserved 4
descriptors loop length 12
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 4: DVB SI Tables
6.5.4.2: DVB Optional SI Tables
Figure 6.5.4.2d Time Offset Table (TOT)
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 45Rev -, July 2001 Vol 6: Digital Video
Sec 5: Digital Video Broadcasting
6.5.5: Satellite Standards (DVB-S)
Figure 6.5.5a Typical MPEG 2 Encoded DVB Compliant Satellite Delivery System
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 46Rev -, July 2001
MPEG 2video
encoder
MPEG 2audio
encoderMPEG 2
audioencoder
MPEG 2video
encoder
MPEG 2audio
encoderdata
encoder
programMUX
programMUX
MPEG 2audio
encoder
programMUX
transportMUX
Typical MPEG 2 Program Encoding, Program Mux and Transport Stream Mux Block Diagram
Vol 6: Digital Video
Sec 5: Digital Video Broadcasting
6.5.5: Satellite Standards (DVB-S)
Figure 6.5.5b
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 47Rev -, July 2001
MUXadaptation& energydispersal
outercoding(Reed
Solomon188/204)
innercoding
(convolu-tional code)
Qbasebandshapping
QPSKModulator
Functional Block Diagram of a DVB Compliant Satellite QPSK Modulator
I
convolut.interleaving
I = 12 bytes
BB
Interface& Sync
data
CK
clock & sync generator and rate control
Vol 6: Digital Video
Sec 5: Digital Video Broadcasting
6.5.5: Satellite Standards (DVB-S)
Figure 6.5.5c
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 48Rev -, July 2001
Functional Block Diagram of a DVB Compliant Satellite QPSK Demodulator
carrier & clock recovery
DEMUXadaptation& energydispersalremoval
outercoding
decoder(Reed
Solomon188/204)
innercoding
decoder(Viterbi)Q
MatchedFilter
QPSKDemod
I convolut.interleaving
I = 12 bytes
BB
Interface& Sync
data
U
Syncdecoder
clock & sync generatorcode rate control
Vol 6: Digital Video
Sec 5: Digital Video Broadcasting
6.5.5: Satellite Standards (DVB-S)
Figure 6.5.5d
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 49Rev -, July 2001 Vol 6: Digital Video
Sec 5: Digital Video Broadcasting
6.5.5: Satellite Standards (DVB-S)
Figure 6.5.5e Typical RF Transmit (Uplink) and Receiver (Downlink) Systems Used for Satellite Distribution
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 50Rev -, July 2001
MUX Adaptation and Energy DispersalThe input of the DVB modulator will consist of the MPEG 2 transport stream. The DVB modulator will output a modulated or unmodulated carrier centered at 70 or 140 MHz.
The MPEG 2 transport stream will be organized in fixed length packets of 188 bytes including 1 synch word-byte (01000111 - 47 Hex).
To avoid the emission of an unmodulated carrier and to ensure adequate binary transitions, the data of the MPEG 2 transport stream must be randomized in a process shown in the next slide.
The randomization is required to comply with ITU Radio Regulations.
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 5: Satellite Standards (DVB-S)
6.5.5.1: MUX Adaptation and Energy Dispersal
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 51Rev -, July 2001
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
1 0 0 1 0 1 0 1 0 0 0 0 0 0 0In itia lization sequence
ex-orand
ex-or00000011...
Enable C lear/random izeddata input
Random ized/de-random ized
data output
Randomizer/de-random izer Diagram
PR BS G enerator
PR BS O /P Enable/D isable
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 5: Satellite Standards (DVB-S)
6.5.5.1: MUX Adaptation and Energy Dispersal
Figure 6.5.5.1 Randomizer/de-randomizer Diagram
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 52Rev -, July 2001
MUX Adaptation and Energy DispersalA Pseudo Random Binary Sequence (PRBS) generator is used in the randomizing/de-randomizing process. The polynomial for the PRBS generator shall be
1 + X14 + X15
A sequence of 1001010100000000 is inserted at the start of every eight transport packets.
The sync byte of the first packet of the group of eight is bit-wise inverted from 47 Hex to B8 Hex. This is done to provide an initialization signal for the descramblers . The process is referred to as the “Transport Multiplex Adaptation”.
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 5: Satellite Standards (DVB-S)
6.5.5.1: MUX Adaptation and Energy Dispersal
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 53Rev -, July 2001
MUX Adaptation and Energy DispersalThe generation of the PRBS sequence will continue during the transmission of the DVB transport packet but its output will be disabled. This will aid the synchronization of the bit stream.
The output of the PRBS generator will be activated when there are no bits being inputted in the modulator or if a non-compliant MPEG 2 stream is provided to the input of the modulator.
This is done so as to ensure that the modulator does not output a non-modulated carrier to the satellite.
The PRBS period has a length of 1503 bytes (7 x 188 bytes + 1 x 187).
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 5: Satellite Standards (DVB-S)
6.5.5.1: MUX Adaptation and Energy Dispersal
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 54Rev -, July 2001
Forward Error Correction (FEC)There are two process of forward error correction defined by the DVB standard for satellite operation:
Outer Coding: based on Reed Solomon code (188/204)
Inner Coding: punctured convolutional codes
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 5: Satellite Standards (DVB-S)
6.5.5.2: Forward Error Correction (FEC)
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 55Rev -, July 2001
Outer Coding (RS)The outer coding is intended to work with the MPEG 2 framing structure for a multiplexed transport stream. The MPEG 2 packet is composed of 187 bytes of data with 1 sync byte.
187 bytesSync1 byte
Packet from a M ultip lexed M PEG 2 Transport Stream
The randomized transport packet will resemble something like this:
R187 B
Sync8
Random ized Transport Packet
R187 B
Sync1
R187 B
Sync2
R187 B
Sync3
R187 B
Sync4
R187 B
Sync5
R187 B
Sync6
R187 B
Sync7
R187 B
Sync8
R187 B
Sync1
PRBS period = 1503 bytes
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 5: Satellite Standards (DVB-S)
6.5.5.2: Forward Error Correction (FEC)
Figure 6.5.5.2a Packet from a Multiplexed MPEG 2 Transport Stream
Figure 6.5.5.2b Randomized Transport Packet
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 56Rev -, July 2001
Outer Coding (RS)The Reed Solomon code RS (204,188, T=8) is applied to each randomized transport packet (188 bytes) to generate an error correction code at the packet level.
187 bytesSync1 byte
Error Pro tected Packet Using Reed Solom on Code RS (204,188,8)
RS (204,188,8)16 bytes
204 bytes
The new data stream is:
203Bytes
Sync8
203Bytes
Sync1
203Bytes
Sync2
203Bytes
Sync3
203Bytes
Sync4
203Bytes
Sync5
203Bytes
Sync6
203Bytes
Sync7
203Bytes
Sync8
203Bytes
Sync1
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 5: Satellite Standards (DVB-S)
6.5.5.2: Forward Error Correction (FEC)
Figure 6.5.5.2c Error Protected Packet Using Reed Solomon Code RS (204, 188, 8)
Figure 6.5.5.2d New Data Stream
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 57Rev -, July 2001
Inner CodingThe DVB standard states that a DVB compliant modulator or receiver will be support convolutional coding with code rates of 1/2, 2/3, 3/4, 5/6 and 7/8. Other rates can be used, but as a minimum these five rates must be implemented before a system is considered compliant to the DVB standard.
When trying to lock to a carrier, a receiver will try each of the code rate until it acquires lock.
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 5: Satellite Standards (DVB-S)
6.5.5.2: Forward Error Correction (FEC)
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 58Rev -, July 2001
Convolutional InterleavingThe convolutional interleaver is a set of shift registers with fixed delays. Convolutional interleaving is used in conjunction with the inner convolutional coding process.
Satellite induced errors tend to be bursty in nature, and Reed Solomon coding is not at its best when faced with bursts of errors. Convolutional interleaving is used to distribute the information in a given packet across multiple packets. If the resultant data stream in now subjected to a bursty error, the affected bits are then de-interleaved and the error is spread evenly over the entire data stream. The Reed Solomon algorithm can now treat these as dribble errors and correct for them.
The interleaver is specified by a maximum interleaving depth usually denoted by I. In a DVB compliant system, I is set to 12. To help the synchronization, all sync bytes are processed through the first path (path “0”) of the interleaver and de-interleaver.
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 5: Satellite Standards (DVB-S)
6.5.5.3: Convolutional Interleaving
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 59Rev -, July 2001
F unctiona l B lock D ia g ram o f a D V B C om plian t C o nvo lu tion a l In te rle ave r an d D e-in terle ave r
M =17B
2*M = 34B
3*M = 51B
4*M = 68 B
5*M = 85 Bytes
11*M = 187 Bytes
.
.
.
FIFO shift reg istors
C onvo lu lt ion a l In te rle ave r C on vo lu lt ion a l D e -in te rle ave r
M =17B
2*M = 34B
3*M = 51B
4*M = 68 B
5*M = 85 Bytes
11*M = 187 Bytes...
Sync W ord Route
Sync W ord Route
1 byte perposition
1 byte perposition
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 5: Satellite Standards (DVB-S)
6.5.5.3: Convolutional Interleaving
Figure 6.5.5.3a Functional Block Diagram of a DVB Compliant Convolutional Interleaver and De-Interleaver
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 60Rev -, July 2001
203Bytes
Sync8
R ee d S o lom o n P acke t (204 by tes)
1
204 bytes
2 3 4 5 6 7 8 9 10 11 12
T w e lve C on secu tive P acke ts a t the Inpu t o f th e C on vo lu tiona l In te rlea ve r
204 bytes
Packet 1Byte 1 to 17
(Packe t 1 to 12)
Packet 2Byte 18 to 34
(Packe t 1 to 12)
Packet 3Byte 35 to 51
(Packet 1 to 12)
Packet 4Byte 52 to 68
(Packe t 1 to 12)
Packet 5Byte 69 to 85
(Packet 1 to 12)
Packet 12Byte 188 to 204(Packet 1 to 12)
. . .
T w e lve R esu lting P acke ts a t the O u tpu t o f the C onvo lu tiona l In te rleaver
204 bytes
Packet 1Byte 1 to 17
(Packe t 1 to 12)
Packet 2Byte 18 to 34
(Packe t 1 to 12)
Packet 3Byte 35 to 51
(Packet 1 to 12)
Packet 4Byte 52 to 68
(Packe t 1 to 12)
Packet 5Byte 69 to 85
(Packet 1 to 12)
Packet 12Byte 188 to 204(Packet 1 to 12)
. . .
T w e lve P acke ts a t the Inpu t o f the C onvo lu tiona l D e -in te rleave r
1
204 bytes
2 3 4 5 6 7 8 9 10 11 12
T w e lve R esu lting P acke ts a t the O u tpu t o f the C onvo lu tiona l D e -in te rlea ve r
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 5: Satellite Standards (DVB-S)
6.5.5.3: Convolutional Interleaving
Figure 6.5.5.3b
Figure 6.5.5.3c
Figure 6.5.5.3d
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 61Rev -, July 2001
Baseband Shaping and QPSK ModulationSatellite transmissions are notorious for distortions in phase and amplitude. Consequently, we have to use a modulation technique that is sturdy enough to survive these distortions.
The most used modulation technique is Quadrature Phase Shift Keying (QPSK). This mode of modulation is sometimes referred to as four phase shift keying (4-PSK).
In QPSK modulation, a cosine carrier is varied in phase while keeping a constant amplitude and frequency. Data signal are represented by the change in phase between two time periods.
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 5: Satellite Standards (DVB-S)
6.5.5.4: Baseband Shaping and QPSK Modulation
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 62Rev -, July 2001
I = 0Q = 0
I = 0Q = 1
I = 1Q = 1
I = 1Q = 0
+x-x
+y
-y
Baseband Shaping and QPSK ModulationThe data being transferred is represented as the combination of two amplitude modulated signals such that
s(t) = xcos(t) + ysin(t)
s(t) = I + Q signals
The two signals are phase offset by 90°.
Where a value of :
+x equals I = “0”, +y equals Q = “0”
-x equals I = “1”, -y equals Q = “1”
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 5: Satellite Standards (DVB-S)
6.5.5.4: Baseband Shaping and QPSK Modulation
Figure 6.5.5.4a Baseband Shaping and QPSK Modulation
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 63Rev -, July 2001
+x-x
+y
-y
As indicated previously, digital satellite transmission is subject to distortion in phase and amplitude.
A QPSK modulated system is more robust to these distortions. The following drawing shows a constellation of points that were recorded over time. Each point shows a displacement from its ideal phase/amplitude location.
Even with these slight distortions, however, we can still recognize the samples as one of the four states defined in QPSK modulation.
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 5: Satellite Standards (DVB-S)
6.5.5.4: Baseband Shaping and QPSK Modulation
Figure 6.5.5.4b Baseband Shaping and QPSK Modulation
Baseband Shaping and QPSK Modulation
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 64Rev -, July 2001
Modulation Inner Code Spectral Modem Note 1
Efficiency Implementation(bits/symbol) (dB) (dB)
QPSK 1/2 0.92 0.8 4.5QPSK 2/3 1.23 0.8 5.0QPSK 3/4 1.38 0.8 5.5QPSK 5/6 1.53 0.8 6.0QPSK 7/8 1.61 0.8 6.48PSK 2/3 1.84 1.0 6.98PSK 5/6 2.30 1.4 8.98PSK 8.9 (note 2) 2.46 1.5 9.416QAM 3/4 (note 2) 2.76 1.5 9.016QAM 7/8 3.22 2.1 10.7
Note 1: Required Eb/No for BER = 2x10-4 before RS and QEF after Reed Solomon
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 5: Satellite Standards (DVB-S)
6.5.5.5: Performance Requirements
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 65Rev -, July 2001
Performance Requirements Example of Bit Rates Versus Transponder Bandwidth
BW BW Rs Ru Ru Ru Ru Ru(at 3 dB) (at 1 dB) 1.28 1/2 2/3 3/4 5/6 7/8[MHz] [MHz] [Mbaud] [Mbps] [Mbps] [Mbps] [Mbps] Mbps]
54 48.6 42.2 38.9 51.8 58.3 64.8 68.046 41.4 35.9 33.1 44.2 49.7 55.2 58.040 36.0 31.2 28.8 38.4 43.2 48.0 50.436 32.4 28.1 25.9 34.6 38.9 43.2 45.433 29.7 25.8 23.8 31.7 35.6 39.6 41.630 27.0 23.4 21.6 28.8 32.4 36.0 37.827 24.3 21.1 19.4 25.9 29.2 32.4 34.026 23.4 20.3 18.7 25.0 28.1 31.2 32.8
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 5: Satellite Standards (DVB-S)
6.5.5.5: Performance Requirements
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 66Rev -, July 2001
Conditional Access (DVB-CA) Currently, any DVB compliant receiver or decoder can decode a DVB stream and display the content of its elementary stream. In the case of a broadcast program ANY DVB compliant receiver or decoder could have access to any video and audio program within the DVB stream.
This works well in most cases, but many broadcasters are concerned with copyright issues or distribution issues. In their view they cannot permit everyone to have access to their program while it is transmitted over satellite. To prevent unauthorized viewers from getting access to the program within a DVB stream, we have to add a Conditional Access (CA) system to the DVB stream at the encoding location. We can then use this CA system to control who has access to the content of the DVB stream.
Vol 6: Digital Video
Sec 5: Digital Video Broadcasting
6.5.6: Conditional Access (DVB-CA)
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 67Rev -, July 2001
Conditional Access (DVB-CA)A conditional access system can be considered as having two parts: the decryption and the descrambling systems.
The decryption translates coded keys received by the IRDs that are necessary for the proper operation of the descrambling system.
The descrambler takes the coded keys to unscramble the video and audio programs within a DVB stream. In other words, the descrambler is used to make the receive pictures and sound intelligible. This is done based on information provided by the decryption system.
Standardization of the CA system has been deemed undesirable, since a single common CA standard is more vulnerable to hacking, which could mean loss of revenue to many broadcasters.
Vol 6: Digital Video
Sec 5: Digital Video Broadcasting
6.5.6: Conditional Access (DVB-CA)
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 68Rev -, July 2001
Conditional Access (DVB-CA)CA technology has, in the past, worked in a closed manner. Each manufacturer used its own structures and rules for its CA system. Information on CA systems were seldom shared between companies.
After many discussions within the DVB group, it was decided to propose the following CA standards and recommendations:
SimulCrypt
MultiCrypt
General CA Measures and Recommendations
Vol 6: Digital Video
Sec 5: Digital Video Broadcasting
6.5.6: Conditional Access (DVB-CA)
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 69Rev -, July 2001
SimulCrypt A Common Scrambling Algorithm allows the same program (with different embedded CA bitstreams) to be viewed on several receivers with different CA systems.
The DVB stream would be used to carry multiple CA messages required to enable the scrambled program within the different receivers.
The DVB SimulCrypt system is based on the concept of shared scrambling and descrambling methods
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 6: Conditional Access (DVB-CA)
6.5.6.1: SimulCrypt
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 70Rev -, July 2001 Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 6: Conditional Access (DVB-CA)
6.5.6.1: SimulCrypt
Figure 6.5.6.1 SimulCrypt System Architecture
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 71Rev -, July 2001
SimulCryptEvent Information Scheduler (EIS) - Provides the necessary
information to the DVB table to update the EIT table (SI Generator). It also provides information to the ECMG regarding changes in CA for different programs within a PES.
SimulCrypt Synchronizer (SCS) - Acquires the control words (CW) from the CWG. Supplies the CW to the ECMGs. Acquires ECMs from the ECMGs. Synchronizes ECMs with their associated Crypto Period (CP). Submit ECM to the MUX. Supplies CW to the scrambler for the duration of the CP.
Entitlement Control Message Generator (ECMG) - Generates ECMs based on CWs received from the SCS.
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 6: Conditional Access (DVB-CA)
6.5.6.1: SimulCrypt
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 72Rev -, July 2001
SimulCryptEntitlement Management Message Generator (EMMG) - The
EMMG is supplied by the manufacturer. The EMMG initiates connections to the MUX.
Private Data Generator (PDG) - The PDG is similar to the EMMG but is used to carry other CA related private data.
Custom Service Information Generator (SIG) - Generates private service information (SI). It interfaces with the SI and PSI generators.
Multiplex Configuration (MUX Config) - As the name implies, this interface is used to configure the multiplexor.
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 6: Conditional Access (DVB-CA)
6.5.6.1: SimulCrypt
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 73Rev -, July 2001
SimulCryptSI Generator - Generates the Service Information Tables (SIT).
It takes information from the EIS and the Custom SI servers supplied by the CA providers.
Program Specific Information (PSI) Generator - Generates the Program Specific Information for the system.
Multiplexer (MUX) - Multiplexes the program transport streams, plus SI tables, PSI tables and CA information (EMMs, SCS)
Scrambler (SCR) - Specification for the common scrambling system is not available. The information is considered confidential and its access is limited by the ETSI.
Control Word Generator (CWG) - for security reason the CWG definition is not available.
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 6: Conditional Access (DVB-CA)
6.5.6.1: SimulCrypt
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 74Rev -, July 2001
MultiCryptThe MultiCrypt standard defines a common interface between a standard PCMCIA module and a DVB receiver.
The PCMCIA card is used as a smart card or a CA reader that can be inserted in a DVB compliant receiver for CA descrambling. The smart card is configured to operate with a known CA system.
To descramble a DVB compliant signal, the user must find the appropriate smart card compatible with the CA system used. The common interface allows a user to use the same receiver to receive different signals that have been scrambled using different CA system. It is only necessary to have the appropriate smart card for each CA system.
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 6: Conditional Access (DVB-CA)
6.5.6.2: MultiCrypt
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 75Rev -, July 2001 Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 6: Conditional Access (DVB-CA)
6.5.6.2: MultiCrypt
Figure 6.5.6.2a DVB Receiver Using Common Interface for CA (DVB-CI)
MultiCrypt
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 76Rev -, July 2001
DVB Measures and Recommendations • Code of conduct for access to digital decoders
• Recommendations for anti-piracy legislation for digital video broadcasting
• Licensing of CA systems to manufacturers should be on fair and reasonable terms and should not exclude the common interface
• CA systems should allow simple transcontrol. Cable operators should be able to remove CA used for satellite and terrestrial distribution and the add their own CA data
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 6: Conditional Access (DVB-CA)
6.5.6.3: DVB Measures and Recommendations
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 77Rev -, July 2001
DVB Interfaces The DVB group has defined the following three interface standards:
ASI Asynchronous Serial Interface
SPI Synchronous Parallel Interface
SSI Synchronous Serial Interface
Of the three interfaces, ASI is the one currently being used by the industry.
Vol 6: Digital Video
Sec 5: Digital Video Broadcasting
6.5.7: DVB Interface
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 78Rev -, July 2001
DVB InterfacesASI Asynchronous Serial Interface
75 ohm BNC connector270 MbpsUni-directional transmission link
SPI Synchronous Parallel Interface25 D type connectorTwo version of SPI specification
• LVDS (Low Voltage Differential Signaling)- use low voltage swing of about 350 mV- ANSI/TIA/EIA-644
• Parallel Emitter Coupled Logic (ECL)SSI Synchronous Serial Interface
SMPTE 310M
Vol 6: Digital Video
Sec 5: Digital Video Broadcasting
6.5.7: DVB Interface
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 79Rev -, July 2001
Other DVB StandardsThis presentation is intended to cover satellite distribution. A short description of the DVB standard for cable distribution and digital terrestrial television will be provided in this section. Further information on these distribution methods can be obtained from the following DVB standards
• EN 300 429 Framing Structure, Channel Coding, and Modulation for Cable Services
• EN 300 744 Framing Structure, Channel Coding, and Modulation for Digital Terrestrial Television
Vol 6: Digital Video
Sec 5: Digital Video Broadcasting
6.5.8: Other DVB Standards
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 80Rev -, July 2001
DVB Standards for Cable Services This standard is similar to the one proposed for the DVB-S services. Cable service does not use QPSK modulation as it is better served by using 16QAM, 32QAM, 64QAM, 128QAM or 256QAM.
Useful Ru Total Ru Cable Occupied Modulation
(w RS) Symbol Rate BW Scheme[Mbps] [Mbps] [Mbaud] [MHz]
38.1 41.34 6.89 7.92 64 QAM31.9 34.61 6.92 7.96 32 QAM25.2 27.34 6.84 7.86 16 QAM18.9 20.52 3.42 3.93 64 QAM16.0 17.40 3.48 4.00 32 QAM12.8 13.92 3.48 4.00 16 QAM9.6 10.44 1.74 2.00 64 QAM8.0 8.70 1.74 2.00 32 QAM6.4 6.96 1.74 2.00 16 QAMVol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 8: Other DVB Standards
6.5.8.1: DVB Standard for Cable Services (DVB-C)
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 81Rev -, July 2001
MUXadaptation& random iz
ation
outercoding(Reed
Solom on188/204)
differencia lencoding
basebandshapping
QAMm odulator
C on cep tu a l B lo ck D ia g ram o f C a b le H ead -en d
convolut.interleaving
I = 12 bytes
BB
Interface& Sync
data
CK
clock & sync generator and rate contro l
Byte to m -tuple
conversion Q
I
C oncep tua l B lo ck D ia gra m o f C a b le IR D
carrier, clock and sync recovery
energydispersalrem oval
outerdecoding
(ReedSolom on188/204)
differencialdecoding
m atchedfilter
&equalizer
QAMdem od
convolut.de-
interleaving
I = 12 bytes
BB
Interface& Sync
data
CK
sym bol tobyte
m appingQ
I
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 8: Other DVB Standards
6.5.8.1: DVB Standard for Cable Services (DVB-C)
Figure 6.5.8.1a Conceptual Block Diagram of Cable Head-end
Figure 6.5.8.1b Conceptual Block Diagram of Cable IRD
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 82Rev -, July 2001
DVB Standards for Digital Terrestrial Television The standard for digital terrestrial television, DVB-S and DVB-C share a common platform. The changes between the three standards are usually only those required to deal with the different medium used to distribute the signal.
DVB-S has to deal with interference from analog and digital signals transmitted to/from neighboring transponders or satellites. Satellite receivers are also affected by bursty noise caused by local RF interference.
DVB-C defines operation in a closed environment where the only problems are loss due to the cable run and distortion due to the medium. Both problems are usually reduced by the addition of equalizers and amplifiers in the network. The cable distribution usually has to deal with a fixed medium with limited bandwidth.
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 8: Other DVB Standards
6.5.8.2: DVB Standard for Digital Terrestrial Television (DVB-T)
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 83Rev -, July 2001
DVB Standards for Digital Terrestrial TelevisionFor digital terrestrial television, we have to share the UHF frequency band with other analog transmission. Any digital transmission in this frequency band will be subject to a high level of co-channel interference (CCI) and adjacent channel interference (ACI) from NTSC/PAL/SECAM analog services.
The DVB standard defines the use of an OFDM (Orthogonal Frequency Division Multiplexing) system with concatenated error correcting coding.
You can find more information on this standard by referring to EN 300 744 V1.1.2 (1997-08).
Vol 6: Digital Video, Sec 5: Digital Video Broadcasting
Part 8: Other DVB Standards
6.5.8.2: DVB Standard for Digital Terrestrial Television
Technical Introduction to Geostationary Satellite Communication Systems Original Prepared by Telesat Canada
Slide Number 84Rev -, July 2001
DVB Transport Tests The DVB group has defined three levels of potential errors:
Priority 1 Priority 2 Priority 3TS sync Transport NIT
Sync Byte CRC SI Repetition Rate
PAT PCR Buffer
Continuity PCR Accuracy SDT
PMT CAT EIT
PID RST
TDT
Vol 6: Digital Video
Sec 5: Digital Video Broadcasting
6.5.9: DVB Transport Test