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Revision as of 19:19, 23 May 2009

List of digital television broadcast standards
DVB standards (countries)
ATSC standards (countries)
ISDB standards (countries)
DTMB standards (countries)
  • DTMB (terrestrial/mobile)
    • DTMB-A
  • CMMB (handheld)
  • ABS-S (satellite)
DMB standard (countries)
Codecs
Terrestrial Frequency bands
Satellite Frequency bands

Integrated Services Digital Broadcasting (ISDB) is a Japanese standard for digital television (DTV) and digital radio used by the country's radio and television stations. ISDB replaced the previously used MUSE "Hi-vision" analogue HDTV system.

Countries and territories using ISDB-T

Asia/Pacific

Americas

Introduction

DTT broadcasting systems. Countries using ISDB are shown in green.
File:ISDB-T.jpg
A picture of ISDB-T (taken during a tour of the NHK Osaka broadcasting station)

ISDB is maintained by the Japanese organization ARIB. The standards can be obtained for free at the Japanese organization DiBEG website and at ARIB.

The core standards of ISDB are ISDB-S (satellite television), ISDB-T(terrestrial), ISDB-C (cable) and 2.6GHz band mobile broadcasting which are all based on MPEG-2 video and audio coding as well as the transport stream described by the MPEG-2 standard, and are capable of high definition television (HDTV). ISDB-T and ISDB-Tsb are for mobile reception in TV bands. 1seg is the name of an ISDB-T service for reception on cell phones, laptop computers and vehicles.

The concept was named for its similarity to ISDN, because both allow multiple channels of data to be transmitted together (a process called multiplexing). This is also much like another digital radio system, Eureka 147, which calls each group of stations on a transmitter an ensemble; this is very much like the multi-channel digital TV standard DVB-T. ISDB-T operates on unused TV channels, an approach taken by other countries for TV but never before for radio.

Video and audio compression

ISDB has adopted the MPEG-2 video and audio compression system. ATSC and DVB also adopted the same system. DVB and ISDB also provide for other video compression methods to be used, including JPEG and MPEG-4, although JPEG is only a required part of the MHEG standard. In fact Brazil is using ISDB for terrestrial broadcasting (ISDB-T), being that video is being encoded with MPEG-4 AVC (H.264) and audio with HE-AAC ([1]).

Transmission

The various flavors of ISDB differ mainly in the modulations used, due to the requirements of different frequency bands. The 12 GHz band ISDB-S uses PSK modulation, 2.6 GHz band digital sound broadcasting uses CDM and ISDB-T (in VHF and/or UHF band) uses COFDM with PSK/QAM.

Interaction

Besides audio and video transmission, ISDB also defines data connections (Data broadcasting) with the internet as a return channel over several media (10Base-T/100Base-T, Telephone line modem, Mobile phone, Wireless LAN (IEEE 802.11) etc.) and with different protocols. This is used, for example, for interactive interfaces like data broadcasting (ARIB STD B-24) and electronic program guides (EPG).

Interfaces and Encryption

The ISDB specification describes a lot of (network) interfaces, but most importantly the Common Interface for Conditional Access (ARIB STD-B25) with the Common Scrambling Algorithm (CAS) system called MULTI2 required for (de-)scrambling television.

The ISDB CAS system is operated by a company named B-CAS in Japan; the CAS card is called B-CAS card. The Japanese ISDB signal is always encrypted by the B-CAS system even if it is a free television program. That is why it is commonly called "Pay per view system without charge".[citation needed] An interface for mobile reception is under consideration.[citation needed]

ISDB supports RMP (Rights management and protection). Since all digitial television (DTV) systems carry digital data content, a DVD or high-definition (HD) recorder could easily copy content losslessly. Hollywood[who?] requested copy protection; this was the main reason for RMP being mandated. The content has three modes: “copy once”, “copy free” and “copy never”. In “copy once” mode, a program can be stored on a hard disc recorder, but cannot be further copied; only moved to another copy-protected media—and this move operation will mark the content “copy one generation”, which is mandated to permanently prevent further copying. “Copy never” programming may only be timeshifted and cannot be permanently stored. Currently[when?], the Japanese government is evaluating using the Digital Transmission Content Protection (DTCP) "Encryption plus Non-Assertion" mechanism, to allow making multiple copies of digital content between compliant devices[2].

Receiver

There are two types of ISDB receiver: TV and STB (Set top box). The aspect ratio of ISDB television is 16:9; televisions fulfilling these specs are called Hi-vision TVs. There are three TV types: CRT (Cathode ray tube), PDP (Plasma display panel) and LCD (Liquid crystal display), with LCD being the most popular Hi-Vision format on the Japanese market right now.

LCD share as measured by JEITA in November 2004 was about 60%. While PDP set occupies the high end market with units that are over 50 inches (1270 mm), PDP and CRT set shares are about 20% each. CRT set are considered low end for Hi-Vision.

STB is sometimes referred to as digital tuner. High-end ISDB STB have several interfaces:

  • B-CAS card interface to de-scramble.
  • IR interface jack for controlling a VHS or DVD player.

Problems

Though ISDB is a feature-rich system, many problems have surfaced recently.

Copy Protection Technology

Every TV broadcast (including free TV) is encrypted with "Copy-Once", which allows users to record to a digital media (D-VHS, DVD, HDD, etc) but does not allow dubbing to another digital media. On the other hand, the "Copy-Once" technology does not prohibit all types of dubbing. It is possible to dub to an analog media (such as standard VHS) and if recorded to an HDD, it will allow users to "Move" the contents to a D-VHS, but not copy. In contrast, 1seg digital broadcasts which are for low-bandwidth mobile reception and occupy 1/13th of a digital channel, are transmitted 'in the clear' and do not carry copy protection information.

Many users are also very worried about the recent news of severe protection in the future. There are modes in ISDB to not allow the output of signal from an Analog connector (D-connector, Component, Composite, S-Video, etc). There are already plans to not allow analog output for "Copyright Protection" reasons. (Same as Blu-ray and HD DVD) This will make all currently sold STB Tuners, and the majority of LCD/Plasma TVs without HDMI inputs unusable. Plus all analog VHS, D-VHS that can only record via analog input, and all DVD players will also become unusable. These more limiting copy protection technologies will all start after analog broadcasting ends (when there won't be any choice for viewers). Currently, no financial assistance schemes have been announced, and viewers without proper devices will be forced to buy a new compatible TV or set top box in order to view ISDB broadcasts. Though not clear, it is said that there are also plans to protect all programs with "Copy-Never".

The copy protection on ISDB broadcasts can be circumvented with the proper hardware and software.[3]

B-CAS Card

The B-CAS card is required to decode all broadcasts. These cards are included with every digital TV or Tuner at no charge. To use this card, you must agree to the statement written on the registration card. Despite the fact that the card must be inserted to watch TV, if you don't agree to the statement, then the user cannot watch digital broadcasts. Essentially, users are "forced" to agree with the statement. Though registration is not required, it is recommended to fully enjoy interactive programs. Unregistered B-CAS card displays a watermark in a corner of the screen, suggesting the user to register. However, many viewers worry about the leaking of personal information, and the power/rights the TV stations have to access personal information for almost every citizen in Japan. In case of loss or destruction, new B-CAS card of the same number can be issued for a fee of 2,000 yen.[4]

Services

  1. One HDTV or up to three SDTV services within one channel.
  2. Provides Data broadcasting.
  3. Interactive services such as games or shopping, via telephone line or broadband internet.
  4. EPG (Electronic Program Guide)
  5. Ability to send firmware patches for the TV/tuner over the air.

ISDB-S

History

Japan started digital broadcasting using the DVB-S standard by PerfecTV in October/1996, and DirecTV in December/1997, with communication satellites. Still, DVB-S did not satisfy the requirements of Japanese broadcasters, such as NHK, key commercial broadcasting stations like Nippon Television, TBS, Fuji Television, tv asahi, TV Tokyo, and WOWOW (Movie-only Pay-TV broadcasting). Consequently, ARIB developed the ISDB-S standards. The requirements were HDTV capability, interactive services, network access and effective frequency utilization, and other technical requirements. The DVB-S standard allows the transmission of a bit stream of roughly 34 Mbit/s with a satellite transponder, which means the transponder can send one HDTV channel. Unfortunately, the NHK broadcasting satellite had only four vacant transponders, which led ARIB and NHK to develop ISDB-S: The new standard could transmit at 51 Mbit/s with a single transponder, which means that ISDB-S is 1.5 times more efficient than DVB-S and that one transponder can transmit two HDTV channels, along with other independent audio and data. Digital satellite broadcasting (BS digital) was started by NHK and followed commercial broadcasting stations on 1 December 2000. Today, SKY PerfecTV!, successor of Skyport TV, and Sky D, CS burn, Platone, EP, DirecTV, J Sky B, and PerfecTV!, adopted the ISDB-S system for use on the 110 degree (east longitude) wide-band communication satellite.

Technical specification

Summary of ISDB-S (Satellite digital broadcasting)

Transmission channel coding Modulation TC8PSK, QPSK, BPSK (Hierarchical transmission)
Error correction coding Inner coding Trellis [TC8PSK] and Convolution
Outer coding RS(204,188)
TMCC Convolution coding+RS
Time domain multiplexing TMCC
Conditional Access Multi-2
Data broadcasting ARIB STD B-24 (BML, ECMA script)
Service information ARIB STD B-10
Multiplexing MPEG-2 Systems
Audio coding MPEG-2 Audio（AAC）
Video coding MPEG-2 Video

Channel

Frequency and channel specification of Japanese Satellites using ISDB-S

Method BS digital broadcasting Wide band CS digital broadcasting
Frequency band 11.7 to 12.2 GHz 12.2 to 12.75 GHz
Transmission bit rate 51 Mbit/s (TC8PSK) 40 Mbit/s (QPSK)
Transmission band width 34.5 MHz* 34.5 MHz
*Compatible with 27 MHz band satellite transponder for analog FM broadcasting.

ISDB-T

History

HDTV was invented at NHK STRL (Japan Broadcasting Corporation's Science & Technical Research Laboratories). The research for HDTV started as early the 1960s, though a standard was proposed to the ITU-R (CCIR) only in 1973. By the 1980s, a high definition television camera, cathode-ray tube, video tape recorder and editing equipment, among others, had been developed. In 1982 NHK developed MUSE (Multiple sub-nyquist sampling Encoding), the first HDTV video compression and transmission system. MUSE used digital video compression, but for transmission frequency modulation was used after a digital-to-analog converter converted the digital signal. In 1987, NHK demonstrated MUSE in Washington D.C. and NAB. The demonstration made a great impression in the U.S. As a result, the U.S. developed its own ATSC terrestrial DTV system. Europe also developed their own DTV system, DVB. Japan began R&D of a completely digital system in the 1980s that led to ISDB. Japan began terrestrial digital broadcasting, using ISDB-T standard by NHK and commercial broadcasting stations, on 1 December, 2003.

Feature

Treeview of ISDB-T, channels, Segments and arranging multiple program broadcasting.

ISDB-T is characterized by the following features:

  • ISDB-T (Integrated Services Digital Broadcasting-Terrestrial) use UHF470 MHz-770 MHz, bandwidth of 300 MHz, allocate 50 channels, namely ch.13-ch.62, each channel is 6 MHz width　 (actually 5.572 MHz effective bandwidth and 430 kHz guard band between channels).
  • These 50 channels, ch.13-ch.62, are called "physical channel（物理チャンネル)".
  • ISDB-T single channel bandwidths 5.572 MHz has number of carriers 5,617 with interval of 0.99206 kHz.
  • ISDB-T allows to switch to two or three SDTV channels instead of one HDTV channel (multiplexing SDTV channels).
  • Each channel is further divided into 13 segments. 1seg uses only single segment, and the remainder can be allocated as (1) one 12-segments HDTV program, (2) three 4-segments SDTV programs, or (3) one 8-segments (Medium Definition) program and one 4-segments SDTV program, broadcasted from a single TV station as the multiple-program arrangement (マルチ編成, Maruchi hensei) in simultaneous broadcasting (see figure).
    • The single segment for 1seg is further divided and broadcasting as multiple-program arrangement.
  • ISDB-T transmits a HDTV channel and a mobile TV channel 1seg within the 6 MHz bandwidth.
  • ISDB-T provides interactive services with data broadcasting.
  • ISDB-T provides EPG (Electronic Program Guides).
  • ISDB-T supports internet access as a return channel that works to support the data broadcasting. Internet access is also provided on mobile phones.
  • ISDB-T provides SFN (Single frequency Network) and on-channel repeater technology. SFN makes efficient utilization of the frequency resource (spectrum).
  • ISDB-T provides robustness to multipath interference ("ghosting").
  • ISDB-T is claimed to allow HDTV to be received on moving vehicles at over 100 km/h (this has not yet been proven in real-world operation); DVB-T can only receive SDTV on moving vehicles, and it is claimed that ATSC can not be received on moving vehicles at all (however, in early 2007 there were reports of successful reception of ATSC on laptops using USB tuners in moving vehicles).
  • 1seg is a mobile terrestrial digital audio/video broadcasting service in Japan. Although 1seg is designed for mobile usage, reception has proved problematic in moving vehicles. Because of reception on high speed vehicle, UHF transmission is shaded by buildings and hills frequently, but reported well receiving in Shinkansen as far as run in flat or rural area.

Adoption

ISDB-T was adopted for commercial transmissions in Japan in December 2003. It currently comprises a market of about 100 million television sets. ISDB-T had 10 million subscribers by the end of April 2005. Along with the wide use of ISDB-T, the price of STB is getting low. The price of ISDB-T STB in the lower end of the market is ¥19800 as of 19 April 2006. Template:Ja icon uniden. By November 2007 only a few older, low-end STB models could be found in the Japanese market (average price U$180,-) showing a tendency towards replacement by high end equipment like PVRs and TV sets with inbuilt tuners. The Dibeg web page (http://www.dibeg.org/news/news-5/news-e5.htm#dn068e) confirms this tendency by showing low significance of the digital tuner STB market in Japan.

Brazil, which currently uses an analogue TV system (PAL-M) that slightly differs from any other countries, has chosen ISDB-T modulation for its DTV format, calling it SBTVD-T (Sistema Brasileiro de Televisão Digital-Terrestre). SBTVD-T differs from ISDB-T in that it uses the H.264 video codec instead of ISDB-T's MPEG2 and an improved tuner. Other than Brazil, there are a few countries, mainly from Mercosul, such as Argentina, Chile and Venezuela are considering ISDB-T-based SBTVD[citation needed][5] which could provide common market benefits from the regional South American development of the technology instead of importing it, as is the case with the other standards. Also, it seems to have an advantage over ATSC and DVB-T in reception tests. Nevertheless, in August 2007 Uruguay officially chose DVB-T + DVB-H as its DTV standard. Chile, which was set to make an official decision on late December 2007 later delayed its decision until March 2008.[6]

The ABERT/SET group in Brazil did system comparison tests of DTV under the supervision of the CPqD foundation. The comparison tests were done under the direction of a work group of SET (the Brazilian Television Engineering Society) and ABERT (the Brazilian Association of Radio and Television Broadcasters). The ABERT/SET group selected ISDB-T as the best choice in digital broadcasting modulation systems among ATSC, DVB-T and ISDB-T. ISDB-T was singled out as the most flexible of all for meeting the needs of mobility and portability. It is most efficient for mobile and portable reception. In June 29, 2006, Brazil announced ISDB-T-based SBTVD as the chosen standard for Digital TV transmissions, to be fully implemented by 2016. By November 2007 (one month prior DTTV launch), a few suppliers started to announce zapper STBs of the new Nippon-Brazilian SBTVD-T Standard, at that time without interactivity.

The implementation rollout in Brazil is proceeding successfully although some say the implementation could be more accelerated. It terms of broadcasting, the implementation plan seems to be on target. In only 8 months since the start, the digital signal is present in 4 state capitals and by the end of 2008 another 3 capitals will receive the signal. In terms of end-customers the implementation could be better, since at the moment it is estimated only 20,000 set-top boxes have been sold. Part of this low sales number can be explained by the prices that in the beginning ranged from BRL 600 to BRL 1,100. However recently new set-top boxes were launched in market at R$300 (aprox US$ 150); that will probably increase set-top box sales. Other reason to explain low sales level is the interactivity service not available yet. That is because the "middleware" developed by Brazilian universities (PUC Rio and Federal Univerity of Paraiba) will be finished only on October/2008. Once finished it is expected the interactivity will be a strong appeal bringing more and more people to Digital TV world.

Addidionally mobile TV was started with success with Samsung and Toshiba cell phones, presenting very high quality and the best: Digital TV service for free! That is very impressive conquest once in a short period since launched Brazil is already offering digital mobile TV for free. In other countries such accomplishment occoured years later, and in some countries like USA and European countries this reality is far from reality and probably won't be for free.

In April, 23 2009 to announced that Peru has decided to adopt ISDB-T as the digital terrestrial television standard. This decision was taken on the basis of the recommendations by the Multi-sectional Commission to assess the most appropriate standard for the country.

Now Argentina is studying the adoption of ISDB-T. The idea is to implement ISDB-T to the whole Mercosur players (exception of Uruguay) with obvious gains in scale. Other countries testing/studying ISDB-T standard: Chile, Venezuela, Ecuador in South America and the Philippines in Asia.

Technical specification

Segment structure

ARIB has developed a segment structure called BST-OFDM (see figure). ISDB-T divides the frequency band of one channel into thirteen segments. The broadcaster can select which combination of segments to use; this choice of segment structure allows for service flexibility. For example, ISDB-T can transmit both LDTV and HDTV using one TV channel or change to 3 SDTV, a switch that can be performed at any time. ISDB-T can also change the modulation scheme at the same time.

s11 s 9 s 7 s 5 s 3 s 1 s 0 s 2 s 4 s 6 s 8 s10 s12

FIGURE: Spectrum of 13 segments structure of ISDB-T
(s0 is generally used for 1seg, s1-s12 are used for one HDTV or three SDTVs)

Summary of ISDB-T

Transmission
channel coding		 Modulation 64QAM-OFDM,

16QAM-OFDM,
QPSK-OFDM,
DQPSK-OFDM

(Hierarchical transmission)
Error correction coding Inner coding,

Convolution 7/8,3/4,2/3,1/2

Outer coding:RS(204,188)
Guard interval 1/16,1/8,1/4
Interleaving Time, Frequency, bit, byte
Frequency domain multiplexing BST-OFDM (Segmented structure OFDM)
Conditional Access Multi-2
Data broadcasting ARIB STD B-24 (BML, ECMA script)
Service information ARIB STD B-10
Multiplexing MPEG-2 Systems
Audio coding MPEG-2 Audio (AAC)
Video coding MPEG-2 Video MPEG-4 AVC /H.264*
  • H.264 used in one segment (1seg) broadcasting for portables and Mobile phone.

Channel

Specification of Japanese terrestrial digital broadcasting using ISDB-T

Method terrestrial digital broadcasting
Frequency band VHF/UHF, Super high band
Transmission bit rate 19 Mbit/s(64QAM)
Transmission band width 5.6 MHz*
  • Compatible to 6 MHz band terrestrial analog TV broadcasting.

2.6 GHz Mobile satellite digital audio/video broadcasting

MobaHo! is the name of the services that uses the Mobile satellite digital audio broadcasting specifications. MobaHo! started its service on 20 October, 2004.

ISDB-Tsb

ISDB-Tsb is the terrestrial digital sound broadcasting specification. The technical specification is the same as ISDB-T. ISDB-Tsb supports the coded transmission of OFDM siginals.

ISDB-C

ISDB-C is cable digital broadcasting specification. The technical specification is developed by JCTEA.

ISDB-Tmm

ISDB-Tmm (Terrestrial mobile multi-media) will use suitable number of segments by station with video coding MPEG-4 AVC /H.264. With multiple channel, ISDB-Tmm will serve for dedicating contents such as sport, movie, music channel and other with CD quality sound. This service will use VHF band, 170-222 MHz after analog television close down in July 2011.

Standards

ARIB and JCTEA developed the following standards. Some part of standards are located on the pages of ITU-R and ITU-T.

Channel Communication Satellite television digital broadcasting Broadcasting

/Communication
Satellite
television

digital
broadcasting		 Terrestrial television digital broadcasting Satellite Sound digital broadcasting Terrestrial Sound digital broadcasting Cable

television

digital broadcasting
Nick name - ISDB-S ISDB-T 2.6 GHz mobile broadcasting ISDB-Tsb 64QAM,

Trans-modulation

(ISDB-C)
Transmission DVB-S ARIB

STD-B20,

ITU-R BO.1408		 ARIB

STD-B31,

ITU-R BT.1306-1		 ARIB STD-B41 ARIB STD-B29, ITU-R BS.1114 ITU-T J.83 Annex C, J.183
Receiver ARIB STD-B16 ARIB STD-B21 ARIB STD-B42 ARIB STD-B30 JCTEA STD-004, STD-007
Server type broadcasting - ARIB STD-B38 -
Conditional access - ARIB STD-B25 (Multi-2) JCTEA STD-001
Service information - ARIB STD-B10 JCTEA STD-003
Data broadcasting - ARIB STD-B24 (BML), ARIB STD-B23 (EE or MHP like) -
Video/Audio compression and multiplexing MPEG-2 ARIB STD-B32 (MPEG) -
Technical report - ARIB TR-B13 ARIB TR-B14 - - -

Table of terrestrial HDTV transmission systems


Table 1: Main characteristics of three DTTB systems
Systems ATSC 8-VSB DVB COFDM ISDB BST-COFDM
Source coding
Video Main profile syntax of ISO/IEC 13818-2 (MPEG-2 - video)
Audio ATSC Standard A/52 (Dolby AC-3) ISO/IEC 13818-2 (MPEG-2 – layer II audio) and Dolby AC-3 ISO/IEC 13818-7 (MPEG-2 – AAC audio)
Transmission system
Channel coding -
Outer coding R-S (207, 187, t = 10) R-S (204, 188, t = 8)
Outer interleaver 52 R-S block interleaver 12 R-S block interleaver
Inner coding Rate 2/3 trellis code Punctured convolution code: Rate 1/2, 2/3,3/4, 5/6, 7/8 Constraint length = 7, Polynomials (octal) = 171, 133
Inner interleaver 12 to 1 trellis code interleaver Bit-wise interleaving and frequency interleaving Bit-wise interleaving, frequency interleaving and selectable time interleaving
Data randomization 16-bit PRBS
Modulation 8-VSB and 16-VSB COFDM
QPSK, 16QAM and 64QAM
Hierarchical modulation: multi-resolution constellation (16QAM and 64 QAM)
Guard interval: 1/32, 1/16, 1/8 & 1/4 of OFDM symbol
2 modes: 2k and 8k FFT 		BST-COFDM with 13 frequency segments
DQPSK, QPSK, 16QAM and 64QAM
Hierarchical modulation: choice of three different modulations on each segment
Guard interval: 1/32, 1/16, 1/8 & 1/4 of OFDM symbol
3 modes: 2k, 4k and 8k FFT


See also

General category

Transmission technology

References

  1. ^ SBTVD
  2. ^ JEITA、地デジのコンテンツ保護策として暗号方式 EPN を提案:ニュース - CNET Japan
  3. ^ Software B-CAS Conditional Access Module with MULTI2 decoder
  4. ^ "B-CAS＊各種手続き＊" (in Japanese). Retrieved 2007-09-01.
  5. ^ http://www.lasegunda.com/detalle_impreso/index.asp?idnoticia=0230112007301S0720004
  6. ^ http://www.engadgethd.com/2008/01/05/chile-delays-digital-television-decision-until-march/
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