Michael Grotticelli /
11.02.2009 12:22 PM
Mobile DTV transmission systems are ready for deployment

With the new A/153 mobile DTV standard now unanimously approved, suppliers of DTV transmission equipment said they are ready with the technology and systems required to leverage part of a station's 19.6Mb/s of allotted spectrum for sending video via terrestrial signals to portable devices. Now it's up to stations to bring these new services to consumers, as many have pledged to do by early next year.

The broadcast industry is looking to the newly adopted ATSC Mobile DTV Standard A/153 as a way to reach more viewers and generate new revenue via real-time programming, emergency alerts and interactive services displayed on mobile devices like laptop computers, in-car entertainment systems and cell phones.

As of this week, Axcera, Grass Valley, Harris and Rohde & Schwarz have all announced field-tested systems that adhere to the ATSC's new specification. All had been waiting for final approval of the A/153 Standard before committing to making specific equipment in quantity.

The basic equipment needed to begin broadcasting mobile video services via the ATSC Mobile DTV spec includes program encoders, a multiplexer, an electronic services guide (ESG) server, and a compatible DTV transmission exciter.

Facilitating easy setup and deployment, all of the competing systems can be configured, controlled and monitored using a Web browser locally or remotely. All commands for automatic monitoring and for the instrument settings are available over an SNMP interface.

Axcera products include the 6X series liquid-cooled, solid-state transmitter; Innovator CX low power, solid-state broadcast and mobile TV transmitter; 8XC series mobile TV base station; and 5720 series MMDS transmitter.

The 8XC series mobile TV base station is compatible with A/153 and all current digital television standards, including DVB-T, DVB-H, DVB-SH, ATSC, CMMB (STiMi), DAB/T-DMB, MediaFLO, and SDARS. The 8XC series transmitters are available in both indoor and outdoor configurations, making them ideal for mobile multimedia applications.

Grass Valley has completed trials of its Thomson ATSC mobile DTV transmission system, and it is now being tested at a station on the West Coast. The mobile video technology is backward compatible with legacy ATSC transmission systems, allowing stations to use their existing DTV channel and the mandated ATSC 8-VSB modulation scheme. It offers several technological advantages, including the use of Mobile/Handheld (M/H) block coding techniques, which helps ensure reliable signal reception.

"This is an exciting time for broadcasters looking to build out mobile video services," said Richard Fiore, senior director for transmissions and mobility at Grass Valley. "Grass Valley has been very careful to develop a robust and reliable system that can be cost-effectively implemented in a very short amount of time."

Grass Valley offers scalable video coding (SVC) on the premium version of its ViBE mobile TV platform. The encoder also features a unique region of interest encoding system. Region of interest is a patented feature that automatically detects the visually interesting area of a picture and crops out nonessential areas. It allows broadcasters to repurpose "large screen" content for smaller displays associated with mobile and other handheld devices, further enhancing the user's experience with the mobile content.

The company also offers mobile DTV multiplexer (mux) and IP encapsulator (IPE) functions with its NetProcessor 9030 platform, which is available with a large variety of interfaces (DVB-ASI, GigE/IP, ATM, etc.) and handles IP data injection and bit rate management. In addition to mux and IPE functions, the NetProcessor 9030 contains the Signaling Server for the generation of TPC, FIC, and SSC tables specified as part of the A/153 standard. Broadcasters that already have deployed the standard Grass Valley ATSC 9030 NetProcessor can be software upgraded for compatibility with ATSC mobile DTV services.

Harris has been involved in the development of the A/153 standard from the beginning, including two years of work co-developing the physical layer of the standard with LG and Zenith and two years working within the ATSC Technical Standards Group.

The commercialized Harris ATSC mobile DTV platform includes the software-definable Harris Apex M2X exciter and the Harris NetVX networking platform, which has a mobile video encoder, multiplexer and encapsulator built-in. Harris offers electronic program guide technology from Roundbox and Triveni Digital to generate the required program stream and data information. The company is also providing financing options, available through its alliance with National City Media Finance, a division of National City Commercial Capital Company.

WOWT-DT, NBC affiliate in Omaha, NE, is now on the air with the Harris platform — the only station in its market that is pursuing a mobile video strategy — even though there are few who can actually receive the signal.

Jim Ocon, vice president of technology for Gray Television, said he expects to see the first consumer devices available at stores in early 2010 if not the end of this year.

For its part, Rohde & Schwarz announced the successful installation of an ATSC mobile DTV multiplexer and exciter for the new A/153 mobile DTV standard at WNUV-DT, the local Fox affiliate in Baltimore, MD. Rohde & Schwarz is also a main supplier for Qualcomm's FLO-TV mobile video technology in the United States.

One of the key products used at WNUV-DT for its ATSC mobile DTV operation is the R&S SX800 frequency agile exciter, which can be found in the newest ATSC and NTSC medium power air-cooled and high-power liquid-cooled transmitter systems from Rohde& Schwarz. It is also available for use in transmitters made by other manufacturers. Introduced in 2006, R&S SX800 supports all worldwide TV broadcasting standards, including ATSC, MediaFLO, DVB-T/H, ISDB-Tb, and now, ATSC Mobile DTV. The unit is also single-frequency network (SFN) capable, enabling it to be used among a ring of low-power transmitters to ensure signal strength. Existing ATSC A/53 transmitters that use the R&S SX800 exciter can be updated to ATSC A/153 effortlessly.

The heart of the system is the new R&S AEM100 emission multiplexer, which includes the IP encapsulator, a signaling generator and the mobile DTV multiplexer. This single RU high product fully supports ATSC mobile DTV and SFN operation, and is easily integrated into existing installations, leaving the standard ATSC A/53 multiplexer in place.

The R&S AEM100 comes with the SFN function already integrated. The company said that this function, which can be optionally activated, makes it possible to supply the ATSC mobile DTV transport stream from the multiplexer to several transmitters. It allows simultaneous transmission on the same frequency in SFNs. The advantages for network operators are obvious: They can address coverage problems to serve more viewers without having to apply for additional frequencies.

Mark Aitken, director of advanced technology for the Sinclair Broadcast Group, said engineers at WNUV-DT were able to perform a "flash upgrade" of the station's existing R&S SX800 exciters in the transmitters to the new ATSC mobile DTV standard.



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