Mobile TV

Mobile TV is the latest technology where the TV services are streamed on to the mobile or hand-held devices. Mobile TV is going to get more and more prevalent over the next couple years . There is lot of momentum in the area, even if there are a few commercial products so far.

Already, many mobile operators offer a selection of television channels or individual shows, which are streamed across their third-generation (3G) networks. In South Korea, television is also sent to mobile phones via satellite and terrestrial broadcast networks, which is far more efficient than sending video across mobile networks; similar broadcasts will begin in Japan soon. In Europe, the Italian arm of 3, a mobile operator, recently acquired Canale 7, a television channel, with a view to launching mobile- TV broadcasts in Italy in the second half of 2006. Similar mobile- TV networks will also be built in Finland and America, and are being tested in many other countries.

At the moment, mobile TV is mostly streamed over 3G networks. But sending an individual data stream to each viewer is inefficient and will be unsustainable in the long run if mobile TV takes off. So the general consensus is that 3G streaming is a prelude to the construction of dedicated mobile- TV broadcast networks, which transmit digital TV signals on entirely different frequencies to those used for voice and data. There are three main standards: DVB-H (Digital Video Broadcasting - Handhelds) , favoured in Europe; DMB (Digital Multimedia Broadcasting), which has been adopted in South Korea and Japan; and Media FLO , which is being rolled out in America. Watching TV using any of these technologies requires a TV -capable handset, of course. Among the three technologies, DVB-H was officially adopted by ETSI (the European Telecommunications Standards Institute) as the standard for mobile TV services in Europe.

Just as there are several competing mobile- TV technologies, there are also many possible business models. Mobile operators might choose to build their own mobile- TV broadcast networks; or they could form a consortium and build a shared network; or existing broadcasters could build such networks. Some channels will be given away for free, while others are for paying subscribers only. The outcome will vary from country to country, depending on the regulatory environment and the availability of spectrum. In Italy, 3 bought Canale 7 to get its hands on its spectrum and its broadcaster's licence; in Britain, Finland and America, the scarcity of spectrum makes shared networks most likely.

Among the various mobile TV technologies, the likeliest near-term solution will be to unify under the ETSI-endorsed DVB-H standard. It is considered to be is the best delivery system currently available for most markets, according to many of the operators and vendors.

DVB-H:

DVB-H is a terrestial digital TV standard that uses less power in receiving client than DVB-T (DVB Terrestial), and allows the receiving device to move freely while receiving the transmission, thus making it ideal for mobile phones and haldheld computers to receive digital TV broadcasting over the digiTV network (without using mobile phone networks at all) .
The basic DVB-T television standard has been modified to enable the receivers to be less power hungry, as DVB-T is used in an environment where power consumption is not a major consideration. This power reduction has been achieved by time slicing so that the receiver is only switched on in those time intervals when viewing the channel of interest. These intervals could be anything between a few milliseconds and a few seconds. It therefore reduces power consumption by being switched off for the rest of the time when non-required data is being transmitted. There is therefore a trade off between the data rate required for the service and how much this can be packed into short bursts to save the battery power of the receiver.

Like DMB, DVB-H uses COFDM but with a bandwidth of either 6, 7, or 8 MHz. Additionally it uses a range of different types of modulation from QPSK up to 64QAM and this enables it to have a very high data rate. However it is more susceptible to signal variations and synchronisation problems. Additionally higher transmitter powers are required than those needed for DMB. Also frequencies that are likely to be used have not yet been allocated but it is thought they might be within the existing television bands. The wide RF bandwidth also means that current drain is increased, as wide bandwidth amplifiers are inherently more power hungry.

As it is really just an extension to DVB-T, DVB-H uses the same specs DVB-T. Video is normally encoded with MPEG-2 (but can be encoded with MPEG-1 as well, although very rarely used) and the standard, just like its other siblings DVB-C (Cable) , DVB-S (Satellite) and DVB-T, is mostly used in Europe.

Benefits of DVB-H:

An approved standard for handheld equipment by ETSI (European Telecommunications Institute) with a high adoption rate worldwide
DVB-H is an open industry standard that was developed by the DVB Project , an industry consortium and is currently being supported by leading companies throughout the wireless industry.
It benefits from existing DVB-T infrastructure components, which reduces initial investments in many cases
It provides the best user experience in the mobile environment, with an energy saving handset that is only ‘on’ 10% of the time, programme guide, soft handover and in-building coverage
It offers an excellent, broadcast-quality picture, because the screen resolution is of a similar standard to VHS
Battery consumption is reduced by 90% due to time-slicing technology
DVB-H comes from the proven DVB standard used in Europe for standard DTV transmission with a low power mode for battery-powered devices.
Efficient use of bandwidth enables up to 55 mobile channels plus scalability
It is supported by publicly available air interface specifications helping to drive device interoperability and market development
Its security includes end-to-end control of stream encryption, generation of decryption keys and delivery of keys to consumers in a billing-integrated way
It will be accessible by an estimated audience of approximately 300 million mobile users by 2006