Sandeep Kumar, Technical & Broadcast Operations, Times Group
DVB-T2 Digital Video Broadcasting – Second-Generation Terrestrial – is the latest broadcast transmission standard for digital TV, adopted by many European and Asian countries. The spectrum used for transmission of data over the air is a scarce resource. To ensure optimum utilization of this valuable resource, over 156 countries signed an ITU agreement in 2006 to switch from analog to digital transmission.
There are many DTTB standards available for digital terrestrial transmission like DVB-T, DVB-T2, ISDB-T, ATSC, CMMB and DMB-T but most of the countries which adopted other DTTB standards are planning to shift DVB-T2 or trying to improve their existing DTTB standards to be on the same plane as DVB-T2.
DVB-T2 has a great advantage over satellite broadcasting dish-to-home (D2H) technology. DVB-T2 has a capacity to transmit approx. 600–800 SD/HD TV channels and is
30 percent cheaper as compared to satellite broadcasting. Reception/Signal quality is very good even in bad weather; even in a moving car or train, you can watch a live broadcast with crystal-clear quality.
DVBT-T2 supports multi-format HDTV, SDTV, 3-D TV; pictures are free from ghosting and snowing. In DVB-T2, we can broadcast signals in multiform; same transmitter can provide signal for mobile, laptop, TV, and other handheld devices, with time/frequency sliced and fixed services in the same bandwidth .
It uses Orthogonal Frequency Division Multiplex (OFDM) modulation technique QPSK, 16QAM, 64QAM, 256QAM with option of choosing different compression techniques like MPEG2 and GSE or MPEG-4AVC, H.264 SVC along with LDPC (low-density parity check) coding combined with BCH (Bose-Chaudhuri-Hocquengham) error control coding. These codes assure a better protection, allowing more data to be transported in a given channel. They also show a steeper behavior in the relation of BER to C/N, Max. data rate (@ 20 dB C/N) 47.8 Mbps, i.e., they move closer to the ideally desired brick wall behavior and provide excellent performance in the presence of high noise levels and interference. As before, several options are available in areas such as the number of carriers, guard interval sizes, and pilot signals, so that the overheads can be minimized for any given transmission channel.
IP over DVB-T2 services like Internet, LTE A+ overlay are feasible with DVB T2. UHF band has a potential to provide mobile Internet broadband services to rural areas and that will help greatly to fulfill one of the millennium development goals of bridging the digital divide. The digital dividend at the DVB-T2 is far better than other DTTB standards because this is an advanced second-generation DTTB standard, where we get more than 50 percent throughput as ISDB-T and DVB-T systems gave; they also use some PAPR reduction technique to overcome the problem found in DVB-T and ISDB-T; ISDB-T and DVB-T2 use time interleaving techniques, which make the system more efficient during mobile environment and less power is needed for the transmitter.
Provision for Emergency Data
DVB-T2is called as early warning system (EWS). Only DVB-T2, ISDBT, CMMB, and DMB-T systems have this type of provision which can alert consumer in case of natural disaster and can prevent thousands of lives.
How to Receive DVB-T2 Signal
Users who have DVB-T2 tuners built in their TVs will not need a set-top box – just Yagi antenna (fish bone type) connected to their TV antenna connector.
Those with old TVs not having DTV tuners have to buy a DVB-T2 set-top box or a DVB-T2 USB dongle for their computers/laptops. Many mobile companies are coming up with inbuilt DVB-T2 receivers.
DVB-T2 is bound to see a significant level of take-up over the coming years. If we combine all the advantages of DVB-T2 system, we can say this is beneficial for all consumers, broadcasters, and the government, and it is a game-changing technology with great potential.