World’s Broadcasters Plan Broadcast TV’s Future
Consumer electronics have changed significantly since the ATSC (Advanced Television Standards Committee) was formed 30 years ago in 1982. The first version of the ATSC DTV standard still in use today was published in 1995 and adopted by the FCC in 1996, 16 years ago. TV broadcasters now have to target devices ranging from flat screens TV sets that could be 65-inch or larger to handheld tablets and smartphones. Soon, they may have to provide ultra-high-definition TV programming to the next generation of TV sets.
Meanwhile, there are still viewers watching TV on analog CRT TV sets using converter boxes. The need to reach any viewing device—anywhere--has led broadcasters worldwide to look for the “next generation” broadcast platform. This year saw the launch of the Shanghai Declaration.
This international effort follows the ATSC's announcement last September of the formation of a new ATSC technology group to explore next-generation broadcasting. At the October, 2012 IEEE Broadcast Symposium in Washington D.C., Jim Kutzner provided an update on ATSC 3.0.
The ATSC is following a process that started with the definition of use cases, leading to scenarios employing these use cases, and finally to a set of requirements. Work on developing scenarios and target attributes is continuing. Some of the major categories Kutzner listed at the IEEE Symposium include high spectral efficiency, improved reliability and robustness, flexible system configurations, and support for multiple terminal characteristics (fixed, mobile, and handheld).
We can get an idea of what a next-generation broadcast system might involve by looking at the work DVB has done with DVB-T2 and DVB-NGH. Those standards are based on COFDM, and allow different modulation and error correction techniques (constellation size and block length, for example) to trade off robustness and data rate, and support for multiple transmitting antennas (MIMO or MISO, for example) to improve robustness and data rates. Support for multiple transmitters, either to fill-in coverage and improve the signal from a single main transmitter site, or as part of a cellular-type network will also be important. The additional transmitters will provide the signal levels necessary to reach portable and handheld devices indoors. The higher signal level will also enable the use of less robust modulation and coding, thus allowing higher data rates to be transmitted.
This year I provided an introduction to the DVB-NGH as well as the basics of COFDM transmission and reception Part 1 and Part 2.
I also outlined some of the challenges broadcasters will implementing OFDM. You can find my articles on the TV Technology Digital Editions site.
I'll provide more information on the technology for next generation broadcasting in my 2013 TV Technology columns, starting in January with a summary of presentations on the future of broadcast TV at the 2012 IEEE Broadcast Symposium.
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