Michael Grotticelli /
10.19.2009
Originally featured on BroadcastEngineering.com
Mobile DTV standard approved by ATSC

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.”

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.

Brandon Burgess, president of the OMVC and CEO of ION Media Networks, led a demonstration of the M/H service for government officials and others riding around Washingtion, D.C., last week to announce the approval of the standard. Seven Washington-area TV stations transmitted live local news, weather, sports and favorite programs to mobile DTV-compatible devices including mobile phones, laptop computers and netbook PCs. Senior representatives of the participating DTV stations, ATSC, the Association for Maximum Service Television (MSTV), the National Association of Broadcasters (NAB) and technology companies participated in the dialog about the new standard and the new mobile services it will support.

“The leadership and support provided by OMVC made it possible for ATSC to adopt the mobile DTV standard and meet the aggressive timetable required by the industry,” said Mark Richer, president of ATSC. “To meet the technological challenges of sending digital television services to mobile and handheld devices within the existing DTV transmission was an impressive achievement made possible by industry cooperation. Consumers will soon reap the benefits from this innovative use of broadcast digital television.”

The five Washington-area stations participating in last week’s demonstration will also be conducting a consumer showcase of the new mobile DTV services over the next several months. Programming choices will not be limited to favorite local and network shows on mobile devices, but will also include live emergency alerts, local news and sports, as well as interactive services that are still in development.

Technology manufacturers such as LG Electronics, Samsung Electronics, Harris, Rohde & Schwarz and Dell have produced prototype devices and working transmission systems.

Beyond live broadcasts, the OMVC envisions mobile services such as emergency alerts that can be customized by market or location, live audio feeds, datacasting with traffic maps, closed captioning, clip casting sports and news highlights that could be stored in memory on a device, push video on demand for future viewing, time-shifted television, mobile digital video recording, interactive polling, electronic coupons, targeted advertising, and an electronic service guide for ease of tuning.

The OMVC is composed of 27 members that own and operate more than 450 commercial television stations, as well as the Association of Public Television Stations, Corporation for Public Broadcasting and the Public Broadcasting Service, which represent an additional 360 public television stations.

The ATSC mobile DTV standard is based on vestigial side band (VSB) modulation, with enhanced error correction and other techniques to improve robustness and reduce power consumption in portable receivers, coupled with a flexible and extensible Internet Protocol (IP) based transport system, efficient MPEG AVC (ISO/IEC 14496-10 or ITU H.264) video, and HE AAC v2 audio (ISO/IEC 14496-3) coding. ATSC mobile DTV services are carried in existing digital broadcast channels along with current DTV services without any adverse impact on legacy receiving equipment.

The new standard document is now available online on the ATSC Standards page.


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