Watch TV, transfer files simultaneously

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March 23, 2000
Web posted at: 8:00 a.m. EST (1300 GMT)

by Jason Meserve

(IDG) -- It might not be long before "Who Wants To Be A Millionaire" and your company's inventory updates are flowing across the same airwaves. New technology is being developed that will allow files to be mass broadcast to multiple locations using the digital TV (DTV) broadcast spectrum alongside a regular television broadcast.

The Federal Communications Commission has mandated that all of the nearly 1,600 broadcasters in the U.S. convert to a digital signal by 2006. Each station has been given a 19.4M bit/sec spectrum on which to broadcast, but no financial incentive to convert - just a mandate. To make up for the cost of converting and to add new revenue streams, DTV broadcasters are looking into ways of embedding IP data into their digital broadcast signals.

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A consortium of 12 major broadcasters formed iBlast Networks, which is devoted to providing digital content over DTV broadcast signals. Each of the iBlast partners will dedicate part of its local TV spectrum to content such as music, videos, games and software. Though iBlast targets the consumer market, enterprises may be able to take advantage of this ambient bandwidth in the near future.

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"The television stations will be sitting on bandwidth," says Martin Hall, chief technology officer of Stardust Forums. "If you IP-enable that bandwidth, you can become a de facto ISP."

At the Stardust Forums MCAST 2000 Summit last month in San Francisco, vendors demonstrated some of the many uses of IP Multicast technology in the show's "Splash II" project. Part of Splash II involved KNTV in San Jose embedding MPEG1 video into its DTV broadcast, which was received, via an antenna on the roof of the hotel, by a standard PC at the show. The near-TV quality video was broadcast at 700K bit/sec and viewed with RealPlayer G2 from RealNetworks.

Behind the scenes, the technology is relatively simple. Data coming into the television station is encapsulated into a DTV signal using a media router device such as those from SkyStream Networks and Logic Innovations. The signal is broadcast over the airwaves and received by a standard antenna on top of a building or house. A wire runs from the antenna to a decoder card installed in the PC that converts the signal into usable form. The data is sent using IP Multicast technology.

Given that today's analog television uses about 4M bit/sec for its transmission and high-definition DTV uses around 16M bit/sec of bandwidth, there are still a few megabytes of space left for transmitting other content. In the case of the KNTV demonstration at MCAST, the broadcaster was using 16M bit/sec for its regular programming and around 1M bit/sec for the MPEG1 stream, says Molly Glover, director of new media development at Granite Broadcasting, KNTV's parent company.

Glover says her company is still in the very early phases of testing this technology. "We have done some experimenting," she says. "We're trying to get the word out that this is an asset that broadcasters have and need to understand."

"Are television broadcasters going to broadcast 19.4 megabits 24-7? It's not going to happen," says Clint Chao, vice president of marketing at SkyStream Networks in Mountain View, Calif. "This leaves the remaining bandwidth for insertion of other types of content." For corporations, this could be a relatively inexpensive means of transmitting large data files to remote offices in a given region. Companies could contract with a broadcaster to use the bandwidth overnight if the TV station is off the air. Instead of running leased lines or other high-bandwidth landline connections to satellite offices, companies could just set up antennas on the roof and have their satellite offices receive the latest pricing or inventory information over the airwaves.

"This is great for file transfer or any package delivery where it does not have to be in real time," says Fred Kokaska, product manger at Logic Innovations, one of the companies that makes equipment for encapsulating IP data in a broadcast signal. "Inventory lists or anything like that can be played out and received at all sites at the same time."

Some of the problems with embedding IP data in DTV signals include the limited reach of a given broadcaster and the fact that the communication is one-way. With IP Multicast technology (which is used to transport the signal simultaneously to all recipients) a two-way connection is needed to guarantee reliability, though the technology is designed to support one-way communication between source and target.

There are only a limited number of television stations that have begun broadcasting a digital signal. It will be a while before every market is served by DTV. Broadcasters would also have to add server and incoming data capacity in order to act as an ISP, which could take additional time and money.

Glover says Granite is doing as much experimentation as possible to identify which applications would work best in the broadcast environment. "We're hoping to do a bigger test with consumers in the third or fourth quarter," she says. "It will be more of a test than a service rollout, though."

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