This articleneeds additional citations forverification. Please helpimprove this article byadding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "ISDB" – news ·newspapers ·books ·scholar ·JSTOR(May 2023) (Learn how and when to remove this message) |
List ofdigital television broadcast standards |
---|
DVB standards(countries) |
ATSC standards(countries) |
|
ISDB standards(countries) |
DTMB standards(countries) |
DMB standard(countries) |
Codecs |
|
TerrestrialFrequency bands |
SatelliteFrequency bands |
Company type | Incentive |
---|---|
Founded | 1981 |
Headquarters | Japan |
Integrated Services Digital Broadcasting (ISDB;Japanese:統合デジタル放送サービス,Tōgō dejitaru hōsō sābisu) is a Japanese broadcasting standard fordigital television (DTV) anddigital radio.
ISDB supersedes both theNTSC-J analog television system and the previously usedMUSE Hi-vision analog HDTV system in Japan. An improved version of ISDB-T (ISDB-T International) will soon replace theNTSC,PAL-M, andPAL-N broadcast standards inSouth America and thePhilippines.Digital Terrestrial Television Broadcasting (DTTB) services using ISDB-T started in Japan in December 2003, and since then, many countries have adopted ISDB over other digital broadcasting standards.
A newer and "advanced" version of the ISDB standard (that will eventually allow up to 8K terrestrial broadcasts and 1080p mobile broadcasts via theVVC codec, includingHDR andHFR) is currently under development.[1][2][3]
ISDB is maintained by the Japanese organizationARIB. Thestandards can be obtained for free at the Japanese organizationDiBEG website and at ARIB.
The core standards of ISDB areISDB-S (satellite television),ISDB-T (terrestrial),ISDB-C (cable) and2.6 GHz band mobile broadcasting which are all based onMPEG-2,MPEG-4, orHEVC standard for multiplexing with transport stream structure and video and audio coding (MPEG-2, H.264, or HEVC) and are capable ofUHD, high-definition television (HDTV) and standard-definition television.ISDB-T andISDB-Tsb are for mobile reception in TV bands.1seg is the name of an ISDB-T component that allows viewers to watch TV channels viacell phones,laptop computers, andvehicles.
The concept was named for its similarity toISDN as both allow multiple channels of data to be transmitted together (a process called multiplexing). This broadcast standard is also much like anotherdigital radio system,Eureka 147, which calls each group of stations on a transmitter anensemble; this is very much like the multi-channel digital TV standardDVB-T. ISDB-T operates on unused TV channels, an approach that was taken by other countries for TV but never before for radio.
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 usesPSK modulation, 2.6 GHz band digital sound broadcasting usesCDM, and ISDB-T (inVHF and/orUHF band) usesCOFDM withPSK/QAM.
Besides audio and video transmission, ISDB also defines data connections (Data broadcasting) with the internet as a return channel over several media (10/100 Ethernet, telephone line modem, mobile phone, wireless LAN (IEEE 802.11), etc.) and with different protocols. This component is used, for example, for interactive interfaces like data broadcasting (ARIB STD-B24) and electronic program guides (EPG).
The ISDB specification describes a lot of (network) interfaces, but most importantly, the Common Interface for Conditional Access System (CAS). While ISDB has examples of implementing various kinds of CAS systems, in Japan, a CAS system called "B-CAS" is used. ARIB STD-B25 defines theCommon Scrambling Algorithm (CSA) system calledMULTI2 required for (de-)scrambling television.
The ISDB CAS system in Japan is operated by a company namedB-CAS; the CAS card is calledB-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 digital television (DTV) systems carry digital data content, aDVD or high-definition (HD) recorder could easily copy content losslessly.US major film studios 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 disk 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 prevent further copying permanently. "Copy never" programs may only betimeshifted and cannot be permanently stored. In 2006,[21] the Japanese government is evaluating using theDigital Transmission Content Protection (DTCP) "Encryption plus Non-Assertion" mechanism to allow making multiple copies of digital content between compliant devices.[21]
There are two types of ISDB receiver:Television andset-top box. The aspect ratio of an ISDB-receiving television set is 16:9; televisions fulfilling these specs are calledHi-Vision TV. There are four TV types:Cathode-ray tube (CRT),plasma display panel (PDP),organic light-emitting diode (OLED) andliquid crystal display (LCD), with LCD being the most popularHi-Vision TV on the Japanese market nowadays.
The LCD share, as measured byJEITA in November 2004, was about 60%. While PDP sets occupy the high-end market with units that are over 50 inches (1270 mm), PDP and CRT set shares are about 20% each. CRT sets are considered low end for Hi-Vision. An STB is sometimes referred to as a digital tuner.[citation needed]
Typical middle to high-end ISDB receivers marketed in Japan have several interfaces:
A typical Japanese broadcast service consists as follows:
There are examples providing more than 10 SDTV services with H.264 coding in some countries.
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 asNHK, key commercial broadcasting stations likeNippon Television,TBS,Fuji Television,TV Asahi,TV Tokyo, andWOWOW (Movie-only Pay-TV broadcasting). Consequently,ARIB developed a new broadcast standard called ISDB-S. 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 bitstream 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 work on 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! (the 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.
This table shows the 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-B24 (BML, ECMA script) | ||
Service information | ARIB STD-B10 | ||
Multiplexing | MPEG-2 Systems | ||
Audio coding | MPEG-2 Audio (AAC) | ||
Video coding | MPEG-2 Video |
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-S3 is a satellite digital broadcasting specification supporting 4K, 8K, HDR, HFR, and 22.2 audio.[22]
ISDB-C is a cable digital broadcasting specification. The technical specification J.83/C is developed byJCTEA. ISDB-C is identical to DVB-C but has a different channel bandwidth of 6 MHz (instead of 8 MHz) and roll-off factor.[23]
HDTV was invented atNHK Science & Technology Research Laboratories (Japan Broadcasting Corporation's Science & Technical Research Laboratories). The research for HDTV started as early as the 1960s, though a standard was proposed to the ITU-R (CCIR) only in 1973.[24]
By the 1980s, a high definition television camera, cathode-ray tube, videotape 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 transmissionfrequency modulation was used after a digital-to-analog converter converted the digital signal.
In 1987, NHK demonstrated MUSE in Washington D.C. as well as NAB. The demonstration made a great impression in the U.S., leading to the development of theATSC terrestrial DTV system. Europe also developed a DTV system calledDVB. 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.
ISDB-T is characterized by the following features:
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 receivers is getting low. The price of ISDB-T STB in the lower end of the market is ¥19800 as of 19 April 2006.[25] 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 mid to high-end equipment like PVRs and TV sets with inbuilt tuners. In November 2009, a retail chainAEON introduced STB in 40 USD,[26] followed by variety of low-cost tuners. The Dibeg web page confirms this tendency by showing low significance of the digital tuner STB market in Japan.[27]
Brazil, which used ananalogue TV system (PAL-M) that slightly differed from any other countries, has chosen ISDB-T as a base for itsDTV format, calling itISDB-Tb orinternallySBTVD (Sistema Brasileiro de Televisão Digital-Terrestre). The Japanese DiBEG group incorporated the advancements made by Brazil -MPEG4 video codec instead of ISDB-T's MPEG2 and a powerful interaction middleware calledGinga- and has renamed the standard to "ISDB-T International".[28] Other than Argentina, Brazil, Peru, Chile and Ecuador[29] which have selected ISDB-Tb, there are other South American countries, mainly fromMercosur, such as Venezuela,[30] that chose ISDB-Tb, which providing economies of scale and common market benefits from the regional South American manufacturing instead of importing ready-made STBs as is the case with the other standards. Also, it has been confirmed with extensive tests realized by Brazilian Association of Radio and Television Broadcasters (ABERT), Brazilian Television Engineering Society (SET) andUniversidade Presbiteriana Mackenzie the insufficient quality for indoor reception presented by ATSC and, between DVB-T and ISDB-T, the latter presented superior performance in indoor reception and flexibility to access digital services and TV programs through non-mobile, mobile or portable receivers with impressive quality.[31]
The ABERT–SET group in Brazil did system comparison tests of DTV under the supervision of theCPqD foundation. The comparison tests were done under the direction of a work group of SET andABERT. The ABERT/SET group selected ISDB-T as the best choice in digital broadcasting modulation systems among ATSC, DVB-T and ISDB-T.[citation needed] Another study found that ISDB-T and DVB-T performed similarly, and that both were outperformed byDVB-T2.[32]
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. On 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.
As in 2019, the implementation rollout in Brazil proceeded successfully, with terrestrial analog services (PAL-M) phased out in most of the country (for some less populated regions, analog signal shutdown was postponed to 2023).
This lists the other countries who adopted the ISDB-T standard, chronologically arranged.
Segment structure
ARIB has developed a segment structure calledBST-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 bothLDTV 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 |
The above figure shows the spectrum of 13 segments structure of ISDB-T.
(s0 is generally used for1seg,s1-s12 are used for oneHDTV or threeSDTVs)
Transmission channel coding | Modulation | 64QAM-OFDM, 16QAM-OFDM, QPSK-OFDM, DQPSK-OFDM (Hierarchical transmission) | |
---|---|---|---|
Error correction coding | Data: Inner coding: Convolutional 7/8,5/6,3/4,2/3,1/2 Outer coding: Reed-Solomon(204,188) | TMCC: Shortened code (184,102) of Difference Cyclic Code (273,191) | |
Guard interval | 1/32,1/16,1/8,1/4 | ||
Interleaving | Time, Frequency, bit, byte | ||
Frequency domain multiplexing | BST-OFDM (Segmented structure OFDM) | ||
Conditional Access | Multi-2 | ||
Data broadcasting | ARIB STD-B24 (BML, ECMA script) | ||
Service information | ARIB STD-B10 | ||
Multiplexing | MPEG-2 Systems | ||
Audio coding | MPEG-2 Audio (AAC) | ||
Video coding | MPEG-2 Video | MPEG-4 AVC /H.264* |
Specification of Japanese terrestrial digital broadcasting using ISDB-T.
Method | Terrestrial digital broadcasting |
---|---|
Frequency band | VHF/UHF, super high band |
Transmission bit rate | 23 Mbit/s(64QAM) |
Transmission band width | 5.6 MHz* |
ISDB-Tsb is theterrestrial digitalsoundbroadcasting specification. The technical specification is the same as ISDB-T. ISDB-Tsb supports thecoded transmission of OFDM signals.
ISDB-Tmm (Terrestrialmobilemulti-media) utilised suitable number of segments by station with video coding MPEG-4 AVC/H.264. With multiple channels, ISDB-Tmm served dedicated channels such as sport, movie, music channels and others withCD quality sound, allowing for better broadcast quality as compared to1seg. This service used theVHF band, 207.5–222 MHz which began to be utilised after Japan'sswitchover to digital television in July 2011.
Japan'sMinistry of Internal Affairs and Communications licensed toNTT Docomo subsidiarymmbi, Inc. for ISDB-Tmm method on September 9, 2010.[44][45][46] TheMediaFLO method offered withKDDI was not licensed.[47]
The ISDB-Tmm broadcasting service bymmbi, Inc. is named モバキャス (pronouncedmobakyasu), literally short form of mobile casting on July 14, 2011, and had been branded asNOTTV since October 4, 2011. TheMinister of Internal Affairs and Communications approved the start of operations ofNOTTV on October 13, 2011.[48] Planning the service with monthly subscription fee of 420yen for southKanto Plain,Aichi,Osaka,Kyoto and some other prefectures from April 1, 2012. The deployment plan was to cover approximately 73% ofhouseholds by the end of 2012, approximately 91% by the end of 2014, and 125 stations orrepeaters to be installed in 2016 to covercities nationwide.[49][50]Androidsmartphones andtablets with ISDB-Tmm receiving capability were also sold mainly byNTT DoCoMo, although a separate tuner (TV BoX manufactured byHuawei; or StationTV manufactured byPixela) could be purchased foriPhones andiPads as well as Android smartphones and tablets sold byau by KDDI andSoftBank Mobile to receive ISDB-Tmm broadcasts.
Due to the continued unprofitability of NOTTV,mmbi, Inc. shut down the service on June 30, 2016.[51]
MobaHo! is the name of the services that uses the Mobile satellite digital audio broadcasting specifications.MobaHo! started its service on 20 October 2004. Ended on 31 March 2009
ARIB andJCTEA developed the following standards. Some part of standards are located on the pages ofITU-R andITU-T.
Channel | Communication Satellite television | Broadcasting Communication Satellite television | Terrestrial television | Satellite Sound | Terrestrial Sound | Cable television |
---|---|---|---|---|---|---|
Nickname | - | ISDB-S | ISDB-T | 2.6 GHz mobile broadcasting | ISDB-Tsb | 64QAM, Trans-modulation (ISDB-C) |
Transmission | DVB-S | ARIB STD-B20 | ARIB STD-B31 | ARIB STD-B41 | ARIB STD-B29 | - |
- | ITU-R BO.1408 | ITU-R BT.1306-1 | - | 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 | - | - | - |
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 |
General category
Transmission technology
{{cite web}}
: CS1 maint: archived copy as title (link){{cite web}}
: CS1 maint: archived copy as title (link){{cite web}}
: CS1 maint: archived copy as title (link)