The following article is descriptive of the uses and impact Wi-Fi type of broadband technology
can have and provide for public safety. Public Safety now has its own exclusive spectrum at
4.9 GHz where the following type of solution can benefit from not having to compete with
commercial access points:
----------------------------------------------------------------
Idaho Police
Department Installs WLAN Gear
By Bob Brewin
MAY 05, 2003
Scott Haug, a patrol lieutenant on the police force in Post Falls,
Idaho, decided last year that he wanted to give officers access to
the same kind of applications and information they might use at
the station on their desktop computers, while they were out
patroling the city in their cruisers.
Post Falls is about 25 miles east of Spokane, Wash., in the Idaho
panhandle. Its police department, like many other public safety
agencies in the country, had relied primarily on voice radio for
communications between its dispatch center and patrol cars, an
inefficient and error-prone system.
Although it isn't his primary role, Haug says he took on the
wireless network job because of his interest in computers and
communications, describing himself as a self-taught computer
hobbyist.
Haug's plan was to provide patrol officers with e-mail and direct
access to the FBI's National Crime Information Center database and
give headquarters the ability to rapidly transmit photos of crime
suspects to the patrol cars. Haug says he spent close to a year
researching wireless options that could meet the department's
needs and finally settled on what he calls "nontraditional" use of
802.11b wireless LAN systems.
The department examined but rejected high-speed cellular data
service because even with advanced service, the cellular carriers
offered data rates measured in kilobits per second compared with
802.11b networks that promised raw data rates of 11Mbit/sec., Haug
says.
Backed by a grant of $160,000 from the Department of Justice and
additional funding of $40,000 from the city, Haug built a wireless
network that gave patrol officers the same kind of connectivity
and access to applications they would have at the station over the
60 square miles of the city. The network went live earlier this
year.
Adapting 802.11b Wi-Fi WLAN gear -- which has a range of about 300
feet -- to serve as a WAN covering such a large area proved a
challenge, Haug says. The network required installation of an
infrastructure of 22 Wi-Fi access points from Proxim Corp. in
Sunnyvale, Calif. These access points are interconnected to one
another and police headquarters by five 11Mbit/sec. backbone links
using Proxim Orinoco outdoor routers. They operate in the same
2.4-GHz frequency bands as the access points.
The network, which includes access points on 4,500 foot mountains,
helped ensure coverage over and around hills and trees, which the
city has in generous quantities.
Despite this extensive infrastructure, Haug says the network
manages only 90% coverage. When officers hit a dead spot, they
have to move their cars. "You're never going to get 100% coverage
using 2.4 MHz" in a geographically challenging environment such as
Post Falls, Haug says.
Each of the city's 22 patrol cars now carries a model 5350 laptop
computer from Gateway Inc. in Poway, Calif., equipped with a
Proxim Wi-Fi access card wired to an antenna on the roof that
communicates with the access points.
This citywide, high-speed network gives patrol officers instant
access to the FBI criminal database without having to call a
dispatcher, Haug says. When the officers make a traffic stop and
need to check a driver's license, the system can zip them into the
state's license database. This saves patrol officers a minute or
more per traffic stop, he says.
The in-car computer can also access wireless video cameras
installed at potential crime spots around the city, "allowing the
officers to be almost in two places at one time," Haug says.
Post Falls designed security into the system from the start, Haug
says. The system uses 128-bit encryption, and the service set
identifier broadcast was turned off by access points to thwart
hobbyists who attempt to sniff out Wi-Fi networks using easily
available online tools such as NetStumbler.
Post Falls has also decided to use a dynamic key system on the
access points and clients that changes every 15 minutes; another
way to protect against intruders, Haug says. Jeff Orr, product
marketing manager at Proxim's WAN division, says the Orinoco
outdoor routers used in the backbone provide added security by
using a hard-to-crack proprietary encryption protocol.
Haug says he plans to use the network to extend the police
switchboard directly to the cars, through the use of what he calls
"soft-phone" versions of voice-over-IP WLAN phones. He says he
plans to install voice-over-IP software on the patrol car
computers to allow officers to talk over the soft phones via
headsets.
Alan Reiter, an analyst at Wireless Internet & Mobile Computing in
Chevy Chase, Md., says the Post Falls system illustrates that
Wi-Fi has uses far beyond its original design as a purely
local-area technology. "We have just started to open up the
envelope on Wi-Fi," Reiter says. The Post Falls network shows that
in some cases Wi-Fi can provide higher dates at a lower cost and
better coverage than wide-area cellular data networks.
The Post Falls Police Department's unconventional WLAN system has
already proved itself by ensuring that patrol officers have access
to all the information they need "at their fingertips," Haug says.
A better-informed officer, he says, makes for a safer city.
Source: http://www.computerworld.com