ATSC reports progress on mobile TV standard
The Advanced Television Systems Committee (ATSC) is inching closer to standardizing a modulation scheme that will allow broadcasters to transmit audio and video signals to portable devices within the same frequency band they now use for traditional TV. Last week, the standardization group issued a notice that it had recognized the Mobile-Pedestrian-Handheld (MPH) system as a “candidate standard.” Full standardization is expected sometime in the second or third quarter of next year, after the Feb. 17 analog transmission shutoff date mandated for most broadcasters.
Don’t get too excited; it’s been a long time coming. Aside form the competitive and content rights issues, other market factors have clouded the small screen picture. Given the current economic environment, however — widely expected to last throughout 2009 — new mobile video services that leverage the new standard might be slow to develop due to the additional capital investment (new transmitter boards, studio-to-transmitter lines and antennas) necessary to build out such services. Some may need new towers to make it work.
Add to this that consumer receivers will not be in the market until late next year, and the emerging fact overall is that demand for mobile video services among established players like AT&T, Sprint and Verizon is flat. The immediate future for a profitable local station’s mobile TV service in the United States does not look bright.
The ATSC mobile DTV transmission system is based on vestigial sideband (VSB) modulation coupled with a flexible and extensible IP-based transport, efficient MPEG AVC (H.264) video and HE AAC v2 audio (ISO/IEC 14496-3) coding.
The candidate standard MPH DTV transmission system was selected from three main in-band digital television transmission proposals for determining a Mobile and Handheld (M/H) standard for a commercial mobile TV system to be used by terrestrial stations in the United States. They included the Harris Broadcast/LG Electronic-sponsored MPH scheme; an Advanced Vestigial Sideband (A-VSB) proposal submitted by Rohde & Schwarz and Samsung; and a third submission offered by Thomson (called simply ATSC M/H Terrestrial Broadcast Technology). In recent months, Samsung has come out in support of the MPH mobile DTV system, although it said it would support whatever system was eventually approved.
“The combination of live television and interactive capabilities on mobile and handheld devices is an essential element for the future success of over the air digital television,” said Glenn Reitmeier, chairman of the ATSC board of directors. “Our efforts to develop ATSC mobile DTV are a part of a strategy to provide the broadcast industry with the technical ability to deliver content to consumers on the move. The architecture of the candidate standard will make terrestrial broadcasting an important segment of the Internet.”
The independent demonstration of viability (IDOV) group, part of the Open Mobile Video Coalition (OMVC), field-tested each proposed system in field trials in Las Vegas and elsewhere. The OMVC is a consortium of more than 800 TV stations looking to create a new mobile digital television standard.
This new step toward standardization means vendors can start building receiver chips and other devices based on the MPH spec (a new “ATSC Mobile” logo has been designed that manufacturers can use to promote their mobile DTV products). In addition, the Consumer Electronics Association has launched a special interest group for manufacturers interested in building products to the candidate standard.
Stations can use part of their allotted 19.4Mb/s spectrum to broadcast a signal to mobile devices without interfering with their other digital SD or HD channels. For example, a station could split up its bandwidth into a main channel at 15Mb/s and two subchannels. (In the case of one MPH demo, one stream was sent at about 560kb/s, using 2.2Mb/s, called half rate, and another 2.2Mb/s at about 300kb/s, or one-quarter rate.) This allows a station to replicate its traditional DTV channel for larger mobile devices, like a laptop or an in-car video system and send out a smaller signal for display on a cell phone or handheld player, with its 2in x 3in screen, or to stream pure data.
In order to build out such a mobile service, a station will have to install a special digital exciter into its transmitters that is backward-compatible with the existing 8-VSB transmission system currently mandated for DTV services. The cost to implement mobile DTV is about $250,000 for a new exciter, encoders and multiplexing equipment.
Through application software specifications, the candidate standard also includes support for new interactive TV applications, such as audience voting, through an optional Internet connection on the mobile receiver. It will also allow stations to deploy new data broadcasting services such as providing real-time navigation data for in-vehicle use and providing news and sports highlights in on-demand form to consumers.
The ATSC-M/H candidate standard will soon be implemented in prototype receiver devices for further field tests before final approval is given. Several of these prototypes are expected to be demonstrated at the Consumer Electronics Show next month in Las Vegas.
The ATSC Specialist Group on Mobile & Handheld, chaired by Mark Aitken, director of advanced technology for the Sinclair Broadcast Group, evaluated the initial mobile DTV proposals and drafted the standard. The ATSC Technology & Standards Group, chaired by John Henderson, consultant to the Consumer Electronics Association (CEA), approved elevation of the document to candidate standard after a six-week ballot.
The ATSC-M/H candidate standard consists of eight parts that “together form a complete specification for a broadcast digital television signal that can deliver live television service, data and interactivity to new mobile and handheld receivers, while maintaining backward compatibility with existing DTV receivers,’” the ATSC said.
Once the industry decides on a mobile standard, LG and Samsung will have to convince the major telco service operators, such as AT&T and Sprint, to install the required ATSC M/H chips into new phones. This could be a lot harder to do, due to financial politics, than many are publicly acknowledging. With AT&T and Sprint now using QUALCOMM’s MediaFLO technology to send video, what incentive do they have to include a second chip for local broadcasters’ services?