DVB-T2
DVB-T2 (abbreviation for English " D igital V ideo B road casting - T errestrial, 2 nd generation" ; German as "Digital video broadcasting - ground-based antenna television , second generation") is the successor standard DVB-T . It describes the distribution of digital radio, television and data signals by means of terrestrial transmission . Compared to its predecessor, DVB-T2 is characterized by a higher spectral efficiency . This enables a higher number of programs to be transmitted, which also have a higher technical quality. DVB-T2 is not compatible with DVB-T .
Features of DVB-T2
Extract from the system requirements of the DVB consortium:
- Focus on stationary reception, although mobile and portable reception should be possible.
- Improvement of the robustness of the signal (configurable differently for each service).
- Increase the size of single-frequency networks by at least 30 percent.
- Increased user friendliness through shorter switching times.
- More economical distribution through more efficient use of the frequency band. This means that with the same bandwidth requirements, more programs with better quality, including HDTV , can be broadcast.
- Transmit diversity (better coverage through two transmitting antennas - multiple input multiple output concept).
- Different bandwidths defined.
- Steeper drop in the spectrum edges.
technology
In October 2009 the DVB-T2 standard was published by the European Telecommunications Standards Institute (ETSI) under EN 302 755 V.1.1.1.
- Use of COFDM as a modulation method : In addition to the 2K and 8K modes known from DVB-T, a 16K or 32K mode can also be used, which allows larger single-frequency networks . In addition, the 16K and 32K FFT modes allow a relatively shorter guard interval for the same size of the single frequency network , which leads to an increased user data rate.
- Use of 256- QAM : QPSK , 16-QAM and 64-QAM were used for DVB-T . These enable the transmission of 2, 4 or 6 bits per symbol . However, DVB-T2 will also include the option for 256-QAM, which enables transmission of 8 bits per symbol. The higher signal field strength required for this is partially compensated for by the new forward error correction .
- New forward error correction : By using new error correction mechanisms, the signal field strength required for error-free reception can be reduced a little. The choice fell on a code from the group of LDPC codes ( Low Density Parity Check Code ).
- Use of MISO technology: MISO (Multiple Input - Single Output) uses several transmitting antennas. The robustness of the signal can be increased considerably by using special channel properties.
On June 3, 2008 a data sheet of the DVB group was published. The standard was ratified by the Steering Committee in June 2008. The following table summarizes the main technical differences between DVB-T and DVB-T2, in bold the additional options for DVB-T2:
| DVB-T | DVB-T2 | |
|---|---|---|
| Forward Error Correction (FEC) |
Convolution code + RS code 1/2, 2/3, 3/4, 5/6, 7/8 |
LDPC + BCH code 1/2,3/5,2/3, 3/4,4/5,5/6 |
| modulation | QPSK , 16- QAM , 64-QAM | QPSK, 16-QAM, 64-QAM, 256-QAM |
| Guard interval | 1/4, 1/8, 1/16, 1/32 | 1/4, 19/128, 1/8, 19/256, 1/16, 1/32, 1/128 |
|
Discrete Fourier Transform (DFT) block length |
2k, 8k | 1k, 2k, 4k, 8k, 16k, 32k |
| Distributed pilot signals | total: 8% | total: 1%, 2%, 4%, 8% |
| Continuous pilot signals | total: 2.6% | total: 0.35% |
Downward compatibility with DVB-T
Downward compatibility with DVB-T is not given for the successor DVB-T2, since the data transmission methods on the radio interface are incompatible with one another. DVB-T2 devices can only receive DVB-T if a DVB-T receiver is also installed. Such devices can continue to be used when the distribution standard is changed.
Use of new image compression methods
Various video compression methods can be used as part of DVB-T2, such as B. MPEG-4 AVC (H.264) or High Efficiency Video Coding (H.265). The video compression method ( video codec ) used is essential for actual television reception and image display, but is not part of the DVB-T2 standard, as the DVB-T2 standard only defines the physical layer of transmission.
business
Specific points on the introduction and operation of DVB-T2 in different countries are summarized in a separate list . DVB-T2 operation and its market policy implications in Germany are summarized in the article DVB-T2 HD , the marketing term introduced in Germany. On the other hand, DVB-T was discontinued in Switzerland on June 3, 2019 without replacement , DVB-T2 was not used there.
literature
- Ulrich Reimers: DVB (Digital Video Broadcasting). 2nd Edition. Springer Verlag, Berlin 2004, ISBN 3-540-43545-X
- Thomas Riegler: DVB-T. Vth 2004, ISBN 3-88180-802-7
- Peter Dehn: TV everywhere very easy, the practical guide to digital TV via antenna. Books on Demand GmbH, Norderstedt 2004, ISBN 3-8334-1163-5
- Manfred Braun u. a .: Network planning and costs of DVB-T. Vitas 1999, ISBN 3-89158-244-7
- Eric Karstens: Digital TV. An introduction. VS-Verlag, Wiesbaden 2006, ISBN 3-531-14864-8
Web links
- Page of the DVB project on DVB-T2 (English)
- Model experiment DVB-T2. Archived from the original on February 8, 2014 ; accessed on September 27, 2014 .
- DVB-T2 has been ratified. heise.de
Individual evidence
- ↑ http://www.etsi.org/deliver/etsi_ts/102800_102899/102831/01.02.01_60/ts_102831v010201p.pdf
- ↑ http://dvb.org/about_dvb/index.xml Presentation of the DVB consortium
- ↑ Archive link ( Memento of the original from September 27, 2007 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Commercial requirements for DVB-T2, see appendix "commercial requirements"
- ↑ Final draft ETSI EN 302 755 V1.2.1 (2010-10). European Standard (Telecommunications series)
- ↑ 2nd Generation T Generation Terrestrial ( Memento from February 6, 2009 in the Internet Archive )
- ↑ Press release on dvb.org of June 30, 2008 (PDF; 28 kB)
