Digital multimedia broadcasting

You can watch TV on a phone.

This is called DMB. It sends shows through the air. It works on phones and in cars.

South Korea was the first place to use it. It sends radio and video to you. Some signals come from space. Other signals come from the ground. You can even watch it in a fast car.

It is a great way to see shows anywhere.

You can watch TV on many small devices.

This is called Digital Multimedia Broadcasting, or DMB. It sends TV, radio, and data through the air. It works on mobile phones, laptops, and car systems.

South Korea started the first mobile TV service in May 2005. DMB uses two main ways to send signals. One way is S-DMB. This uses satellites in space to send shows. The other way is T-DMB. This uses signals from the ground. T-DMB is free to use in some areas.

Many people use DMB in their cars. It works well even in fast cars. A car can go 300 km/h and still see the shows. It even works in tunnels, though the signal might skip. In South Korea, many long-distance buses use T-DMB. This is a great way to watch shows while traveling. Many new phones in South Korea can use DMB. Some phones even have the apps ready to go.

Digital Multimedia Broadcasting, or DMB, is a way to send TV and radio through the air. It allows people to watch shows on mobile phones, laptops, and even car navigation systems.

This technology is often called mobile TV. It is different from Digital Audio Broadcasting, which is used for radio. DMB was created in South Korea as a new way to replace FM radio. It helps send many types of media to small devices.

There are two main ways that DMB works to reach you. One way is called S-DMB, which uses satellites in space to send signals. The other way is T-DMB, which uses terrestrial signals sent from the ground.

T-DMB uses specific radio frequencies to carry video and audio. It uses a system called MPEG-4 to handle the pictures and sounds. To keep the signal strong, it uses a method called error correction. This helps the device fix small mistakes in the data stream. It even works well in cars traveling at 300 km/h.

Scientists and engineers worked hard to build the foundation for this technology. Prof. Dr. Gert Siegle and Dr. Hamed Amor at Bosch in Germany helped lay the groundwork. South Korea then led the way in making it a real service. The world's first official mobile TV service started there in May 2005. In May 2005, they launched S-DMB service. They launched T-DMB service on December 1, 2005. This helped make South Korea a leader in mobile media.

Many interesting facts show how much people use DMB. In South Korea, 14 million DMB receivers have been sold. By December 2006, the T-DMB service had 7 TV channels and 12 radio channels. There were also 8 data channels available. In 2013, a better version called Smart DMB started in South Korea. It improved video quality from 240p to 480p. Later, in August 2016, HD DMB arrived with 720p quality. There are currently 6 HD DMB stations in Seoul.

You might recognize DMB from how we use gadgets today. Many people use it in their cars to watch shows while traveling. In South Korea, long-distance buses use T-DMB instead of satellite TV. It works well even if the video quality is lower than a satellite. While it is used mostly in South Korea, other places use it too. Mexico is one country where many cell phone plans include DMB. Other countries like Norway and Ghana have also used or tested these services.

Digital Multimedia Broadcasting, commonly known as DMB, is a digital radio transmission technology. It was developed in South Korea as part of a national IT project. The goal was to send multimedia content like TV, radio, and data to mobile devices. These devices include mobile phones, laptops, and GPS navigation systems.

DMB is often called mobile TV. It should not be confused with Digital Audio Broadcasting, or DAB. While DAB is a research project for the European Union, DMB was designed to replace FM radio. It serves as a next-generation digital technology for mobile media.

There are two distinct ways that DMB transmits information to users. The first method is S-DMB, which operates via satellite transmission. The second method is T-DMB, which uses terrestrial transmission from the ground.

T-DMB specifically uses band III (VHF) and L (UHF) frequencies. This terrestrial system is designed to work on specific radio bands. Because of how frequencies are used in the United States, DMB is unavailable there. In the USA, those frequencies are reserved for television broadcasting and military applications. Instead, the US uses different standards like ATSC-M/H or MediaFLO.

The technical mechanism of T-DMB involves several complex layers of data processing. First, the system uses MPEG-4 Part 10, also known as H.264, for video. For audio, it uses MPEG-4 Part 3 BSAC or HE-AAC v2. These audio and video components are encapsulated in an MPEG transport stream. To ensure the signal stays clear, the stream uses forward error correction via Reed Solomon encoding. This process uses a 16-byte long parity word to protect the data. The system also uses convolutional interleaving on the stream. Finally, the DMB modem uses OFDM-DQPSK modulation. This specific modulation helps diminish channel effects like fading and shadowing.

History shows that the foundations of DMB were laid by researchers in Germany. Prof. Dr. Gert Siegle and Dr. Hamed Amor at Bosch provided the technological groundwork. However, South Korea became the pioneer for official mobile TV services. The world's first official service launched in South Korea in May 2005. Specifically, S-DMB service began on May 1, 2005. T-DMB service followed on December 1, 2005. Since then, the technology has evolved through several distinct stages of quality. In January 2013, Smart DMB launched in South Korea, improving quality from 240p to 480p. Later, in August 2016, HD DMB arrived, increasing resolution to 720p using the HEVC.5 codec.

The significance of DMB is evident in its massive adoption rates in South Korea. By December 2006, the T-DMB service offered 7 TV channels, 12 radio channels, and 8 data channels. These were broadcast on six multiplexes in the VHF band. As of April 2013, S-DMB service had grown to include 15 TV channels, 2 radio channels, and 6 data channels. The scale of use is impressive, with 14 million DMB receivers sold in South Korea. This includes both T-DMB and S-DMB models. Notably, 40% of new cell phones in the country possessed DMB capabilities.

There are many notable examples of how DMB functions in real-world environments. T-DMB is remarkably stable for vehicles traveling at speeds up to 300 km/h. While signals may skip occasionally in tunnels or underground areas, the broadcast usually remains available. In South Korea, some long-distance buses have adopted T-DMB instead of satellite TV. Although T-DMB resolution is 240p, which is lower than the 480p or higher found on satellites, it remains a functional choice. DMB is also integrated into various hardware, including car navigation systems, PDAs, and digital cameras.

DMB connects to broader global communication standards and regional technologies. On January 20, 2007, the ITU formally approved T-DMB as a global standard. It was recognized alongside other standards like DVB-H, 1seg, and MediaFLO. Different regions have developed their own ways to reach mobile users. For example, Japan uses the 1seg standard within the ISDB system. In Mexico, many cell phone carriers include DMB broadcasting in basic plans. Other nations, such as Norway, Germany, and Malaysia, have also conducted trials or implemented various forms of mobile broadcasting services.