4.9 GHz Networks More Secure, But a Long Way Off

Jan 1, 2004 12:00 PM, Lynnette Luna

The public-safety community faces a dilemma: Does it make widespread Wi-Fi deployments in the unlicensed 2.4 GHz band today despite the security risks or wait for a better solution?

The Federal Communications Commission has allocated a significant amount of spectrum in the 4.9 GHz band for exclusive use by the public-safety community. The vision is to deploy 802.11-compliant technology in the band so that public-safety groups can realize all the benefits of Wi-Fi without competing with other users clamoring to get on the band.

“The 2.4 GHz band is awfully crowded and prone to interference issues, which would naturally impact safety,” said John Yunker, an analyst with Pyramid Research. “An exclusive frequency will be much more secure by default, simply because you won't have to worry about any upstart local operators causing interference.”

But the road to the 4.9 GHz band contains hurdles. Public-safety organizations are working with 802.11 equipment manufacturers and standards bodies to create a tweaked 802.11 series standard in order to leverage economies of scale and Wi-Fi functionality.

But the effort may be thwarted, because the FCC adopted emission mask standards that are incompatible with emission standards established by the 802.11 community. The National Public Safety Telecommunications Council (NPSTC) and various public-safety agencies are urging the FCC to adopt a scaled orthogonal frequency division multiplex-based emission mask that would ensure Cisco and other 802.11 vendors also would build to the 4.9 GHz band.

“Cisco will not build to this band if the FCC doesn't come up with an emission mask that is 802.11 compliant,” said Steven Devine, who chairs the NPSTC's 4.9 GHz Task Force. “There are manufacturers that want to build equipment for the 4.9 GHz band.”

If the FCC relaxes the emission guidelines, which it initially adopted on the recommendation of Motorola, public-safety organizations immediately could access equipment. Japan already supports Wi-Fi in the 4.9 GHz band, while chipsets are plentiful from global commercial vendors for the 802.11a standard and HiperLAN standard at 5 GHz, which also can be used in the 4.9 GHz band.

Further complicating matters is the commission's adoption of a geographic licensing scheme for the 4.9 GHz band that allows a public-safety entity to seek a non-exclusive license to operate throughout the geographical area within its political jurisdiction. That means a number of agencies must share access to a particular hot spot, which could slow deployments.

“The FCC is looking for a new level of cooperation at the local level,” Devine said. “The more agencies you have sharing, the more the cost goes down. … This is something IT people have never dealt with, and all have to agree on a distribution method. This is a new paradigm of cooperation.”