Grundig Digital Radio manual Mobile Broadcasting Corp. and TU Media Corp. ITU-R System E

DIGITAL RADIO GUIDE SATELLITE TRANSMISSION - MOBILE BC / TU MEDIA

5.3Mobile Broadcasting Corp. and TU Media Corp. – ITU-R System E

Mobile Broadcasting Corporation is a commercial organisation based in Tokyo, Japan and TU Media Corporation is a commercial organization based in Seoul, Korea. Although they have one geostationary satellite in common, each of them can use its own transponders and is independently providing high quality digital audio, medium quality digital video and multimedia data services to vehicular, portable and fixed receivers using the satellite and a number of terrestrial repeaters. The same frequency band, 2630 - 2655 MHz, is used by sharing polarization. The service area of Mobile Broadcasting Corp. is Japan and the service area of TU Media Corp. is Korea. Broadcasting signal can be received by receivers with small antennas. To generate enough EIRP for mobile reception, the satellite is equipped with a large transmitting antenna and high power amplifiers. After the launch of the satellite in March 2004, the commercial service in Japan was started in October 2004, currently including 30 audio channels, 8 video channels and about 60 items of multimedia data services. The commercial service in Korea will be started in May 2005, including 22 audio channels and 12 video channels.

The major issue related to signal propagation in BSS (sound) is signal loss due to blockages on the signal path from the satellite to the receiver. Two techniques are used to overcome this issue. One of them is bit-wise interleaving, which is used to overcome the instantaneous signal loss caused by blockages, such as bridges over highways, in vehicular reception environment. Invalid data generated due to the signal loss are distributed over several seconds through the deinterleaver and corrected through the decoder of forward error correction code in the receiver. The period of the signal loss which can be recovered by this technique is approximately a second. The other method is introducing terrestrial repeaters. The terrestrial repeaters retransmit the satellite signal and are expected to cover the area where signal loss occurs due to blockages, for example, buildings and large constructions. In the circumstances, where terrestrial repeaters exist, multipath fading appears at the receiver because more than two broadcasting signals are received at the same time. The CDM (Code Division Multiplexing) and RAKE combining technique is adopted, so that the same frequency band is used for the satellite and the terrestrial repeaters.

The system was approved by ITU in July 2000 as ”Digital System E’ in Recommendation ITU-R BO.1130, System description and selection for digital satellite broadcasting to portable, vehicular and fixed receivers in the bands allocated to BSS (sound) in the frequency range 1400 – 2700 MHz.”

5.3.1Receiver Systems

The services are provided to persons, to mobile vehicles (automobiles, trucks, boats and airplanes) and to homes. There are several types of receivers for this market at the moment; palmtop receiver, PC card receiver, plug-and-play receiver and mobile phone type receiver. Palmtop receiver is a dedicated receiver with 3.5-inch LCD, which is small and light enough to be carried to any place. PC card receiver is used with a notebook computer and you can enjoy video services on the display and audio services through the speakers while you are using the computer. Plug-and-play receiver is used with cradles, which are installed in car and at home, so that you can use the receiver not only in car but also at home without buying extra receiver. Mobile phone type receiver is embedded in a mobile phone and you can receive video or audio services at anyplace without bringing additional equipment, though the display is rather smaller than that of dedicated palmtop receiver.

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