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DVB T2

 

 

 

What is DVB-T2? DVB-T2 is the world’s most advanced digital terrestrial television (DTT) system, offering more robustness, flexibility and at least 50% more efficiency than any other DTT system. It supports SD, HD, mobile TV, or any combination thereof.

Map of Digital Terrestrial Systems.Blue indicates countries that have adopted or deployed DVB-T,or DVB T2.

 

 

DVB-T2 offers an increased efficiency of 30-50% in its use of spectrum compared to DVB-T

DVB-T is the most widely adopted and deployed DTT standard. Since its publication in 1997, over 70 countries have deployed DVB-T services and 45 more have adopted (but not yet deployed) DVB-T. This well-established standard benefits from massive economies of scale and very low receiver prices.

Like its predecessor, DVB-T2 uses OFDM (orthogonal frequency division multiplex) modulation with a large number of sub-carriers delivering a robust signal, and offers a range of different modes, making it a very flexible standard. DVB-T2 uses the same error correction coding as used in DVB-S2 and DVB-C2: LDPC (Low Density Parity Check) coding combined with BCH (Bose-Chaudhuri-Hocquengham) coding, offering a very robust signal. The number of carriers, guard interval sizes and pilot signals can be adjusted, so that the overheads can be optimised for any target transmission channel.

 


Additional new technologies used in DVB-T2 are:

 

  • Multiple Physical Layer Pipes allow separate adjustment of the robustness of each delivered service within a channel to meet the required reception conditions (for example in-door or roof-top antenna).
  • It also allows receivers to save power by decoding only a single service rather than the whole multiplex of services
  • Alamouti coding is a transmitter diversity method that improves coverage in small-scale single-frequency networks.
  • Constellation Rotation provides additional robustness for low order constellations.
  • Extended interleaving, including bit, cell, time and frequency interleaving.

  • Future Extension Frames (FEF) allow the standard to be compatibly enhanced in the future. As a result, DVB-T2 can offer a much higher data rate than DVB-T OR a much more robust signal.

    As with DVB-T, the new standard targets not just roof-top and set-top antennas, but also PCs, laptops, in-car receivers, radios, smart phones, dongles, and a whole range of other innovative receiving devices. In countries where DVB-T servicesare already on air DVB-T and DVB-T2 services are likely to coexist side-by-side for some time to come, but in green-field countries that have not yet deployed DTT services, there is a unique opportunity to leapfrog directly to DVB-T2 instead of first deploying DVB-T. A future-proof solution!


    A multitude of DVB-T2 set-top boxes and integrated TV receivers are now available and prices have already dropped to around 45 USD. The price difference between comparable DVB-T and T2 integrated TV sets is already negligible. The first country that deployed DVB-T2 is the UK, where DVB-T2 services were launched in March 2010, next to an existing DVB-T service. 2010 and 2011 also saw the launch of DVB-T2 services in Italy, Sweden, and Finland, all of which will be nationwide in the short term. Outside of Europe DVB-T2 pay-TV services were launched in Zambia, Namibia, Nigeria, Kenya and Uganda and many more are expected to follow soon. Advanced trials are currently taking place across the globe and more countries are considering DVB-T2 services, bringing the total of DVB-T2 countries to 57.

    T2-Lite

    T2-Lite is the first additional transmission profile type that makes use of the FEF approach. It was introduced in July 2011 to support mobile and portable TV and to reduce implementation costs. The new profile is defined as a subset of DVB-T2. with two additional LDPC code rates. Because only elements relevant for mobile and portable reception have been included in the T2-Lite subset and the data rate is restricted to 4 Mbit/s per PLP, the implementation (chipset) complexity has been reduced by 50%. The FEF mechanism allows T2-Lite and T2-base to be transmitted in one RF channel, even when the two profiles use different FFT sizes or guard intervals.