History HDTV was invented at
NHK 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. 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 transmission
frequency 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 the
ATSC terrestrial DTV system. Europe also developed a digital TV system called
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.
Features ISDB-T is characterized by the following features: • ISDB-T (Integrated Services Digital Broadcasting-Terrestrial) in Japan use
UHF 470 MHz-710 MHz, bandwidth of 240 MHz, allocate 40 channels namely channels 13 to 52 (previously used also 710 MHz-770 MHz, 53 to 62, but this range was re-assigned to cell phones), each channel is 6 MHz width (actually 5.572 MHz effective bandwidth and 430 kHz guard band between channels). These channels are called "physical channel(物理チャンネル)". For other countries, US channel table or European channel table are used. • For channel tables with 6 MHz width, ISDB-T single channel bandwidths 5.572 MHz has number of carriers 5,617 with interval of 0.99206 kHz. For 7 MHz channel, channel bandwidth is 6.50 MHz; for 8 MHz 7.42 MHz. • ISDB-T allows to accommodate any combination of HDTV (roughly 8 Mbit/s in H.264) and SDTV (roughly 2 Mbit/s in H.264) within the given bitrate determined by the transmission parameters such as bandwidth, code-rate, guard interval, etc. Typically, among the 13 segments, the center segment is used for
1seg with QPSK modulation and the remaining 12 segments for the HDTV or SDTV payloads for 64QAM modulation. The bitstream of the 12 segments are combined into one transport stream, within which any combination of programs can be carried based on the
MPEG-2 transport stream definition. • ISDB-T transmits an
HDTV channel and a mobile TV channel
1seg within one channel. 1seg is a mobile terrestrial digital audio/video broadcasting service in Japan. Although 1seg is designed for mobile usage, reception is sometimes 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. • ISDB-T provides interactive services with data broadcasting. Such as
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
Single-Frequency Network (SFN) and
on-channel repeater technology. SFN makes efficient utilization of the frequency resource (spectrum). For example, the Kanto area (greater Tokyo area including most part of Tokyo prefecture and some part of Chiba, Ibaragi, Tochigi, Saitama and Kanagawa prefecture) are covered with SFN with roughly 10 million population coverage. • ISDB-T can be received indoors with a simple
indoor antenna. • ISDB-T provides robustness to
multipath interference ("ghosting"),
co-channel analog television interference, and
electromagnetic interferences that come from motor vehicles and power lines in urban environments. • ISDB-T is claimed to allow HDTV to be received on moving vehicles at over 100 km/h;
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).
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 adoption of ISDB-T, the price of receivers is decreasing over time. The price of ISDB-T STB in the lower end of the market is ¥19800 as of 19 April 2006. 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 chain
AEON introduced STB in 40 USD, 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.
Brazil, which used an
analogue TV system (PAL-M) that slightly differed from any other countries, has chosen ISDB-T as a base for its
DTV format, calling it
ISDB-Tb or
internally SBTVD (
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 called
Ginga) and renamed the standard to "
ISDB-T International". Other than Argentina, Brazil, Peru, Chile and Ecuador which have selected ISDB-Tb, there are other South American countries, mainly from
Mercosur, such as Venezuela, 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) and
Universidade 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. 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 and
ABERT. The ABERT/SET group selected ISDB-T as the best choice in digital broadcasting modulation systems among ATSC, DVB-T and ISDB-T. Another study found that ISDB-T and DVB-T performed similarly, and that both were outperformed by
DVB-T2. 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 December 2, 2003, Brazil announced ISDB-T-based SBTVD as the chosen standard for digital TV transmissions, to be fully implemented by 2011. By December 2003 (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 2011, 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 2011).
Adoption by country This lists the other countries who adopted the ISDB-T standard, chronologically arranged. • On June 29, 2006, Brazil announced its decision to adopt ISDB-T as the digital terrestrial television standard, by means of presidential decree 5820/2006. • On April 23, 2009, Peru announced its decision 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. • On August 28, 2009, Argentina officially adopted the ISDB-T system calling it internally SATVD-T (Sistema Argentino de Televisión – Terrestre). • On September 14, 2009, Chile announced it was adopting the ISDB-T standard because it adapts better to the geographical makeup of the country, while allowing signal reception in cell phones, high-definition content delivery and a wider variety of channels. • On March 26, 2010, Ecuador announced its decision to adopt ISDB-T standard. This decision was taken on the basis of the recommendations by the Superintendent of Telecommunications. • On May 25, 2010, Costa Rica officially announced the adoption of ISDB-Tb standard based upon a commission in charge of analyzing which protocol to accept. • On June 1, 2010, Paraguay officially adopted ISDB-T International, via a presidential decree #4483. • On June 11, 2010, the Philippines (
NTC) officially adopted the ISDB-T standard. • On July 5, 2010, Bolivia announced its decision to adopt ISDB-T standard as well. • On December 27, 2010, the Uruguayan Government adopts the ISDB-T standard., voiding a previous 1998 decree which adopted the Singaporean DVB system. • On October 2011, the Maldivian Government adopts the ISDB-T standard. and on September 7, 2014 Japanese Prime Minister
Shinzo Abe signed an agreement with Sri Lankan President
Mahinda Rajapakse for constructing infrastructure such as ISDB-T networks with a view to smooth conversion to ISDB-T, and cooperating in the field of content and developing human resources. • On January 19, 2017, El Salvador adopted the ISDB-T standard. • On March 2019, Angola adopted the ISDB-T standard. • On August 10, 2010, Nicaragua adopted the ISDB-T standard.
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. The above figure shows the 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 • H.264 Baseline profile is used in one segment (
1seg) broadcasting for portables and Mobile phone. • H.264 High-profile is used in ISDB-Tb to high definition broadcasts.
Channel Specification of Japanese terrestrial digital broadcasting using ISDB-T.
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 signals.
ISDB-Tmm ISDB-Tmm (
Terrestrial
mobile
multi-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 with
CD quality sound, allowing for better broadcast quality as compared to
1seg. This service used the
VHF band, 207.5–222 MHz which began to be utilised after Japan's
switchover to digital television in July 2011. Japan's
Ministry of Internal Affairs and Communications licensed to
NTT Docomo subsidiary
mmbi, Inc. for ISDB-Tmm method on September 9, 2010. The
MediaFLO method offered with
KDDI was not licensed. The ISDB-Tmm broadcasting service by
mmbi, Inc. is named モバキャス (
pronounced mobakyasu), literally short form of mobile casting on July 14, 2011, and had been branded as
NOTTV since October 4, 2011. The
Minister of Internal Affairs and Communications approved the start of operations of
NOTTV on October 13, 2011. Planning the service with monthly subscription fee of 420
yen for south
Kanto Plain,
Aichi,
Osaka,
Kyoto and some other prefectures from April 1, 2012. The deployment plan was to cover approximately 73% of
households by the end of 2012, approximately 91% by the end of 2014, and 125 stations or
repeaters to be installed in 2016 to cover
cities nationwide.
Android smartphones and
tablets with ISDB-Tmm receiving capability were also sold mainly by
NTT DoCoMo, although a separate tuner (TV BoX manufactured by
Huawei; or StationTV manufactured by
Pixela) could be purchased for
iPhones and
iPads as well as Android smartphones and tablets sold by
au by KDDI and
SoftBank Mobile to receive ISDB-Tmm broadcasts. Due to the continued unprofitability of NOTTV,
mmbi, Inc. shut down the service on June 30, 2016. ==2.6 GHz Mobile satellite digital audio/video broadcasting==