Panel: 4.9 GHz band promising, challenging
Proper engineering standards and area coordination are needed to make 4.9 GHz spectrum dedicated to public safety beneficial to first responders wanting high-speed data access at affordable prices, according to a panel convened at last week’s IWCE 2004 in Las Vegas.
Currently, the Federal Communications Commission is considering engineering standards for the emission mask. Public-safety leaders are hopeful the standards are aligned with the standards for the 500 MHz of 5 GHz unlicensed airwaves available to all consumers, because this would let them leverage equipment advances in affordable 802.11a and 802.11j technologies.
“Failure to do that could create a niche market and correspondingly high equipment prices,” said Sean O’Hara, communications system manager for Syracuse Research and a member of the National Public Safety Telecommunications Council’s software-defined radio work group.
Such a scenario also could mean that the 4.9 GHz spectrum largely would not be used, according to attendee John Powell, a public-safety communications consultant and past president of APCO.
“It makes the difference between a $100 device and a $1000 device,” Powell said after the panel discussion. “[If public safety can’t use consumer-like equipment at 4.9 GHz], we won’t have to worry about interference at 4.9 GHz, because no one will use it.”
O’Hara said he has a “good feeling” that the matter will be resolved in a way that allows public safety to use the same equipment at 4.9 GHz that will be developed in the adjacent 5 GHz band. If this occurs, public-safety communications leaders will have unprecedented options to upgrade their data systems, according to Salvatore DiRaimo, principal engineer for New York State Technology Enterprise Corporation.
“We don’t have to wait 10 years [to afford new technology]; we can adapt in two to three years,” DiRaimo said.
One of the challenges associated with the 4.9 GHz band is that it can be used by all licensed public-safety entities in a region, which means there are possibilities for interference if the groups don’t work together, said Steve Devine, patrol frequency coordinator for the Missouri State Highway Patrol. But a coordinated effort–as well as the ability to use the 5 GHz spectrum during high-traffic periods–should provide the kind of performance that will be a boon to public safety, he said.
“The level of throughput achieved is based on the level of cooperation,” Devine said. “It’s the sand-box theory.”
