With the continued emphasis on homeland security, law enforcement agencies nationwide are eager to take advantage of advanced wireless data applications that would allow them to transmit photos of criminal suspects, building floor plans and blueprints, and surveillance video to officers in the field. One of the challenges to transmitting such rich media is that these are huge files that would choke most public-safety communications networks today.

Solutions are coming, but it's likely going to take several years for them to develop to the point where they are public-safety grade and cost-effective enough to justify their deployment. For instance, the FCC has set aside spectrum for public safety in the 4.9 GHz band, but most products for that band are still at the concept stage.

And while both mesh networks and Flash OFDM-based systems have shown promise for opening the bottleneck, they still are in a nascent stage. Moreover, the prospects for Flash-OFDM dimmed recently when Sprint and Nextel merged. Nextel had been testing the technology for its 3G broadband data platform, but the merger effectively killed those plans, said Rudy Baca, Precursor wireless strategist.

Two companies, SpectraRep and Harris Corp., believe it's time to dust off a technology that has been around for a few years — datacasting — to provide the broadband pipe public safety craves. SpectraRep will begin a pilot program this month with the Las Vegas police and fire departments, while Harris will roll out its platform for public safety at next month's IWCE 2005, also in Las Vegas.

Datacasting leverages unused broadcast spectrum to transmit data traffic one way. Over-the-air TV stations receive enough RF spectrum to broadcast a real-time stream of 19 Mb/s but typically use far less than that, said John Delay, director of strategic management for Harris.

“There is only one FCC regulation and that is to broadcast one standard definition video channel, which takes about four megabytes per second,” Delay said. “It's up to the station to decide how to use the rest of that spectrum.” High-definition signals could eat up most of the remaining spectrum, but Delay is counting on rapidly evolving compression technologies to ease the impact.

Rick Ducey, president of SpectraRep, said now is the time to make a push into the public-safety sector because the U.S. Department of Homeland Security is seeking broadband solutions that leverage existing infrastructure and is doling out grant monies accordingly.

“DHS realized from an information technology perspective, most of the infrastructure was in the private sector, not the public sector,” Ducey said. “They didn't want to spend the time or the money to build a new solution. Time to market and cost are important criteria.”

According to Delay, datacasting requires very little infrastructure cost for public safety because the traffic rides over the already-built broadcast pipe. The only cost, for vehicles that already have a computer on board, would be insertion of a PCMCIA card, equipped with a receiver antenna, into the computer. Some vehicles might also need to mount an external antenna to pick up the signal.

Charles Werner, deputy chief of the Charlottesville, Va., fire department agreed it often doesn't make sense to build new infrastructure when it already exists.

“The real benefit of datacasting will be for smaller departments that don't have the money for infrastructure and won't for a significant time to come,” he said.

Cost is the primary reason that datacasting thus far has been limited to the education sector, where public broadcasting stations use it to transmit specialized programming to schools.

“Now the price points are starting to come down enough where you can start to look at deployments on a wide scale,” Delay said. “In 1999, a [PCMCIA] card was in the $1500 to $2000 range. Today that card is $130.”

However, Ducey conceded that infrastructure costs are only part of the story. For example, building blueprints would have to be converted to digital format before they could be transmitted to fire department personnel at the scene. Also, public-safety agencies would have to pay a fee to broadcasters for their services, as they do to commercial wireless carriers for data transmit services such as EV-DO and IXRTT.

Pricing is still in a nascent stage, Ducey said, and SpectraRep is hoping the Las Vegas pilot program will give it a better sense of what to charge for its service. But, he said, a “rough guess” would be “somewhere around $10,000 per month for a megabyte per second for the bandwidth.”

“We're working on the business models now. We have the ability to transmit data over DTV, but where does it makes sense in the marketplace, and what are the price points,” Ducey said.

Werner believes the price points are going to have to come down a lot. “That's a big figure. Most places aren't going to be able to afford $120,000 a year,” he said.

However, both Delay and Ducey believe federal grant monies could defray at least some of those fees. “That's why we're working the pilot program and have proposals in various hoppers, to see if they can get funded,” Ducey said.

There is some question as to whether broadcasters will cooperate because they might want to put unused spectrum to better commercial use should multicasting ever become a reality. That's one of the reasons SpectraRep primarily targets public broadcast stations.

“The revenue targets of a commercial station are much higher than a public station,” Ducey said. “And that's one of the motivations for public stations — they need new revenue sources.”

However, it would be a mistake to write off commercial stations right now, said National Association of Broadcasters spokesman Dennis Wharton.

“Datacasting, can mean a lot of things in addition to public safety,” he said. “The time is ripe for a lot of experimentation because it is fallow spectrum that has to be cultivated.”