Digital Terrestrial versus Satellite and Cable

 
Digital TV can be received through different transmission media. The most important ones as of today are Satellite, Cable and Terrestrial. Each of these systems bring a series of advantages to the end customer. Satellite for example has the advantage of offering large frequency spectra, about 2 GHz on each geostationary position on earth, which ends up offering a very large choice of programs. The disadvantage of satellite is the lack of low cost return channel, the cost of transmission for a single or small number of users (TV versus Internet), and the requirement to install a parabolic antenna on the roof of the house. Cable on the other hand offer a return channel which gives a very strong advantage with regards to offering Internet access to houses. The disadvantage of Cable is the same as satellite : it requires to have access to a Cable Plug, i.e. to be at home.

Digital Terrestrial Broadcasting has the strong advantage to offer services which can be received anywhere at anytime with a small reception antenna. Therefore, it is possible to imagine customers watching some TV programs or receiving a certain type of information on their screen at home, e.g. weather, traffic information, etc. and wanting to receive the same type of information once they leave their house. Systems such as Wireless Access Protocols (WAP) on mobile phones have addressed this problem, but are facing very strong problems such us the requirement to create specific services for mobile receivers, the very low bitrate (less than 10 kb/s), and the poor interface. With very large bitrates (up to 30 Mb/s) and services deployed for regular TV spectators, DVB-T is a very interesting alternative for receiving services on a portable device.