Mobile DTV standard approved by ATSC
Oct 19, 2009 11:07 AM, By Michael Grotticelli
In one DTV mobile test, WRAL-DT sent a signal from its Harris transmitter (with the required M/H exciter board) to LG Electronics plasmas screens equipped with M/H decoding technology onboard Capital Area Transit buses driving around Raleigh, NC. Microspace Communications provided wireless networking and digital signage system support. A systems integration company called Digital Recorders installed the equipment on the buses.
After more than three years of work, the Advanced Television Systems Committee (ATSC) has adopted a standard for sending video to mobile devices using the same spectrum now used for over-the-air television. It’s officially called the A/153 ATSC mobile DTV standard and is now available for real-world deployment.
The ATSC mobile DTV standard defines the technical specifications necessary for broadcasters to provide new services to mobile and handheld devices using their DTV transmissions. The goal for broadcasters is to extend their programming reach to a growing audience of new viewers — anywhere, anytime and at any speed (since the new mobile DTV signals can be received by viewers in the backseat of a moving car). The standard can also be used for transmission of new data broadcasting services.
The Open Mobile Video Coalition (OMVC), a consortium of some 800 broadcast stations, has tested the new mobile handheld (M/H) standard in several controlled field trials over the past two years with limited success, due to the lack of mobile devices with the necessary receiver chips inside. Yet the scheme of using part of a broadcaster’s 19.4Mb/s of allotted spectrum (and the 8-VSB modulation scheme) for mobile services have proven effective, even in moving vehicles. In trials, stations have used about 6MHz to transmit a single mobile stream of programming services that will not interfere with existing HD and multicast services.
The OMVC said some 70 stations hope to have mobile video services up and running by the end of the year. Getting the receivers in consumers’ hands will be the biggest challenge. Yet, cell phones might not be the first implementation of M/H into the market. New revenue models could include the transmission of advertising and news programming to public transit vehicles and nonmoving digital signage displays, as has been tested on public busses in Raleigh-Durham, NC, by WRAL-DT, the CBS affiliate owned by Capitol Broadcasting Company.
NAB executive vice president Dennis Wharton said that his organization “look[s] forward to the continuing parallel efforts of the Open Mobile Video Coalition to develop industry consensus on bringing these pro-consumer local TV services to market.”
The Open Mobile Video Coalition has staged a number of demonstrations at various conventions to show the capability to receive wireless signals using 8-VSB modulation and part of a broadcaster’s 19.4Mb/s DTV spectrum.
Gary Shapiro, president and CEO of the Consumer Electronics Association, said that approval of the standard would stimulate his members’ companies, including CE chipmakers and equipment manufacturers, to proceed with product development and deployment.
The new standard is mainly based on an initial proposal by engineers at Harris and LG Electronics —called Mobile-Pedestrian-Handheld (MPH). A number of slight refinements were made to fine-tune the specification to make it viable in different parts of the country where propagation can be problematic. Harris has developed a pretested mobile DTV package to transmit a mobile/handheld signal that is now available for deployment. It consists of a Harris Apex M2X exciter and the NetVX networking platform, which features a mobile video encoder, multiplexer and encapsulator. Harris is also working with Roundbox and Triveni Digital to integrate electronic program guide services for program stream and data information.
Whether using transmission technology from Harris or Axcera, Rohde & Schwarz and Thomson Grass Valley (which have all announced M/H-compliant systems), U.S. broadcasters can now deploy digital program services that can be available to consumers on devices ranging from in-car screens to portable DVD players, laptop computers and mobile phones.
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