The Advanced Television Systems Committee (ATSC) is today issuing a Request for Proposals to develop a standard that will enable broadcasters to deliver television content and data to mobile and handheld devices via their DTV broadcast signal. Apparently on a fast track, overviews of proposals are due in June and detailed system descriptions are due in July.

Aldo Cugnini
Analyst

In a press release earlier this year, ATSC President Mark Richer described the development of the new standard, saying, "The ATSC-M/H Standard will facilitate broadcasters’ use of their DTV broadcast channels to provide new services directly to small hand-held receivers, laptop computers and vehicles moving at a high rate of speed. ATSC-M/H will be backwards compatible, allowing operation of existing ATSC services in the same RF channel without an adverse impact on existing receiving equipment." The RFP invites proposals covering a wide range of technologies, including modulation and FEC, transport and signaling mechanisms, and advanced video and audio coding.

Anticipated applications for ATSC-M/H include real-time free television and interactive services, as well as pay-TV and non-real-time programming for delayed playback. Because the existing ATSC transmission standard specifies a 19.39 Mbps signal for all services, any new mobile and handheld service would subtract bandwidth from existing services such as HDTV and multicast SDTV. The RFP anticipates this by stating, "Any … solution should have sufficient flexibility to offer a viable service with bit-rates that do not devalue existing DTV services, inclusive of HDTV." Satellite and cable operators, however, already deliver HDTV at less than the ATSC rate (possibly as low as 10Mbps), with some debate (and even litigation!) regarding the quality. Allotting 2Mbps of transmission capacity to the new service could allow, for instance, about 500kbps for video - sufficient for QCIF resolution using MPEG-4 AVC coding, and leaving possibly-acceptable quality for "easy" (non-sports) HDTV programs.

Unfortunately, the statistical multiplexers (stat-mux) commonly used to trade off bandwidth during multicast transmissions probably can’t be used here, as new services - some of which have already been demonstrated - may all require a fixed bandwidth allocation in order to operate. This means that the efficiency of the multiplex cannot be optimized on the fly, so the advantage of a stat-mux - possibly as much as 50% - probably cannot be utilized with ATSC-M/H.

The RFP also recommends, "Reliability of service for devices operating within the ATSC M/H service area should be comparable to or exceed that of cell phone and other handheld devices enabling similar services." While setting a target of U.S. cell phone performance is not asking for much, the RFP does go on to recommend "Modes of operation … at speeds up to at least 75 mph (120 km/hr)." In addition, video resolutions up to 480p are recommended for "screens installed in vehicles," and up to 352 x 288 (CIF) for "screens in hand-held devices."

Earlier this year, we saw two systems that could be candidates for this standard, A-VSB from Samsung/Rohde & Schwarz, and MPH from LG/Zenith/Harris. (Both systems worked flawlessly at high vehicle speeds.) While the former has made statements regarding their interest in pursuing standardization, the latter (curiously) has not. However, LG seems intent to operate on its own schedule, having yet to provide any details on the system they demonstrated a month ago at NAB, so the accelerated ATSC schedule could be an attempt to prod the manufacturer into public disclosure. With business interests increasing around the world for handheld video services, and competing standards - DVB-H, MediaFLO, and others, even including podcasting - now rolling out in the U.S., expect deployed handheld video services to make splash within 1-2 years. Now someone just has to convince this writer that consumers are interested in such a service.