NAB 2010: Harris, LG Unveil Mobile DTV Enhancement
"Full-Channel" mode aimed at 700 MHz spectrum holders
By Glen Dickson -- Broadcasting & Cable, 4/15/2010 7:58:23 AM
Las Vegas -- Harris Corp. and LG Electronics, which developed the core transmission system used in the new ATSC Mobile DTV standard finalized last fall, have already developed an enhancement to that standard which they demonstrated at NAB.
However, the new "Scalable Full-Channel Mobile Mode", or SFCMM, is aimed more at companies like Dish Network and Qualcomm that secured UHF spectrum during the FCC's 2008 auction of the 700 MHz band. It is designed to let a broadcaster use almost the entire 19.4 Mbps digital TV pipe for mobile DTV, sending as many as 16 different video programs in a 6 MHz channel.
In contrast, the existing Mobile DTV standard, A/153, prescribes that only 14.7 Mbps can be used for mobile DTV streams. That's because traditional broadcasters need to maintain at least one NTSC-equivalent, standard-definition program stream to comply with the requirements of their license, and 4.7 Mbps amply meets that need.
"This is incredibly important for the 700 MHz people, because they're only focused on reaching the mobile users," said Harris Broadcast VP of technology Jay Adrick.
Both LG/Harris and Samsung are developing SFCMM technology, which was first talked about last summer and is now being formally considered by the ATSC with a candidate standard possible this fall. Both companies showed the technology at the Mobile DTV Pavilion on the NAB floor.
Harris and LG, with help from LG subsidiary Zenith, were demonstrating at NAB a complete system with transmitters and receivers that delivered nine multiplexed mobile streams to an array of mobile devices. The system also used the convention digital TV standard, A/53, to deliver a low-resolution "barker" channel to a conventional DTV set as way to promote the mobile services.
The barker channel only took 450 kilobits, allowing the rest of the capacity to deliver the nine mobile streams that were encoded at an average bit rate of about 400 kilobits per second. The remaining bits in the DTV pipe were used for forward-error correction (FEC) to ensure reception of the signal.
Three of the nine streams were delivered in a "compatible mobile mode" that could still be picked up by conventional mobile DTV receivers, while the rest were sent in an "enhanced mobile mode" that would require new receiver chips. Zenith engineer Tim Laud said that if SFCMM technology were to be approved, chip manufacturers would likely develop chips that could receive both types of streams. He added that if a company like Dish were to roll out SFCMM reception capability in mobile receivers, it could only benefit broadcasters' efforts with conventional mobile DTV.
Adrick suggested that there is already strong interest among 700 MHz spectrum-holders in using the technology.
"Once standardized, we believe it will come to market very quickly," said Adrick. "We're working with a number of customers who would like to put this in operation."
LG executives have suggested that some conventional broadcasters, including ION Media, are also interested in SFCMM technology as potentially a better way to monetize their spectrum than launching one or two mobile DTV streams alongside existing high-definition and standard-definition services. But ION Media Chairman and CEO Brandon Burgess flatly rejected that idea when asked about it after a mobile DTV panel discussion at NAB. He said that ION was committed to providing high-definition programming to its viewers along with mobile TV services.
"We're not going to go full-bandwidth," said Burgess.
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