At NAB2007, Harris and LG Electronics will introduce a new mobile in-band digital TV system called MPH, short for Mobile-Pedestrian-Handheld. The system will let television broadcasters continue to transmit a main DTV service stream for existing DTV and HDTV services as well as an MPH stream for mobile reception with special MPH receivers.
According to the companies, MPH is backward compatible with existing ATSC 8-VSB transmission and receiving equipment and offers the ability to receive broadcast signals with a single antenna while moving at high speeds — even through urban areas where large buildings and other structures create dynamic multipath conditions.
MPH is fully compatible with the ATSC transmission standard, including PSIP data and the ATSC A/110 distributed transmitter standard, said Harris vice president Jay Adrick. The new mobile system has been tested in the lab for compatibility and underwent field trials at WBNS-DTV in Columbus, OH.
During the WBNS trials, the station simultaneously transmitted its primary digital HDTV stream and two MHP channels in its allotted 19.4Mb/s DTV channel. A total of 4.4Mb/s were devoted to the MHP channels, said Adrick. The system allows broadcasters flexibility in assigning bandwidth to the in-band mobile channels, depending upon the number of channels they wish to transmit and how robust they desire the mobile channels to be.
LG Electronics envisions a range of potential products employing MPH receivers, said company vice president John Taylor. MPH receivers could be built into cell phones, portable battery-powered digital televisions, personal DVD player/viewers and passenger and commuter vehicles. Where it finds a home ultimately will be up to broadcasters, said Taylor, because localism will play a significant role in how the reception technology is productized.
According to Adrick, an undisclosed manufacturer of automotive receivers is seriously discussing the use of MPH receivers for viewing by children and other passengers in the back seats of vehicles.
MPH receivers also could fill an existing void in the DTV landscape. "We see there is a need for battery-operated digital TV devices in times of emergencies and disasters," said Taylor. "The need for the media and the government to be able to communicate with the public is paramount in a disaster."
To begin transmitting an MPH channel, broadcasters will need an MPH encoder, a transport stream multiplexer to add in an MPH channel and an MPH-enabled exciter, Adrick said. MPH relies on MPEG-4 H.264-based encoding. At NAB2007, Harris will show modular MPH encoders that plug into its NetVX platform.
Adding a single MPH channel to an existing DTV transmitter facility will cost about $100,000, said Adrick. As envisioned by Adrick, a station will be able to add three MPH channels and the necessary playback servers and associated program origination equipment for about $500,000.
At NAB2007, the companies will release a paper with technical details about the MPH system. Harris will feature the MPH technology in its NAB2007 booth (N2502). Those attending the show can also see MPH at the ATSC Hot Spot outside the exhibit floor in the South Hall of the Las Vegas Convention Center on the upper floor.
LG Electronics U.S. research subsidiary Zenith Electronics and Harris jointly developed MPH. The MPH system becomes the second mobile TV system proposed to U.S. broadcasters, joining Samsung's Advanced-VSB system, which has undergone testing by the Sinclair Broadcast Group and was shown publicly at the 2007 CES International trade show in Las Vegas at the beginning of the year.
