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: DVBH, favoured in Europe; DMB, which has been adopted in South Korea and Japan; and MediaFLO, which is being rolled out in America. Watching TV using any of these technologies requires a TV capable handset, of course.
In contrast, watching downloaded TV programmes on an iPod or other portable video player is already possible today. And unlike a programme streamed over 3G or broadcast via a dedicated mobile TV network, shows stored on an iPod can be watched on an underground train or in regions with patchy network coverage. That suggests that some shows better suit the download model, while others are better suited to real time transmission. The two approaches will probably coexist.
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.
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