July 5, 2007 By Creighton Welch
The Dallas Police Department was having trouble covering its growing downtown area. The department of 3,500 found it difficult to man the streets at all hours of the day. So in January, the city - the state's third-largest - installed 40 wireless surveillance cameras that now help police cover 30 percent of the downtown district with the hopes of preventing would-be lawbreakers and catching those brazen enough to still commit crime.
"Our goal was to reduce crime in the downtown business district and combat the perception of inadequate safety measures in the area," said Dallas Deputy Police Chief Tom Lawrence, who oversaw the project. "We were pleasantly surprised at the speed of implementation and the tremendous support from the business community."
In the Central Business District, where according to The Dallas Morning News, there was a 32 percent decrease in crime from the first quarter of last year, the cameras operate on wireless technology that not even the Police Department had a complete grasp of at first.
"While we did not go into the project with the concept of wireless," Lawrence said, "the benefits quickly became obvious: The mesh enables quick setup of the network without a complete overhaul, while providing excellent bandwidth and security for video streams."
Put to the Test
Once the idea came about, the Police Department began to test various camera surveillance systems and noticed decreases in crime with only a few hours of actual surveillance per day. The department then set out to find a vendor for the project, and chose one in its own backyard: Dallas' BearCom, a provider of wireless communication devices.
In 2004, the Police Department performed a surveillance study. "They learned a lot from this exercise," said Kent Huffman, chief marketing officer at BearCom. "They then went to companies, and BearCom came with a different solution than everyone else."
That challenge involved how to transmit nonstop, capturing video footage 24 hours a day, 365 days a year from 40 cameras. In other words, the Police Department had to figure out how to record all of its video without clogging up all of the communication lines and bandwidth in the city.
BearCom's solution was to go wireless. Rather than congest the department's communication backbone, or dig up lines for cable, which would make downtown traffic an even bigger nightmare, the company decided to simply install the cameras on top of light posts and on buildings, without the wires.
"This eliminated a lot of problems," Huffman said.
With an $840,000 donation from the Meadows Foundation - a group devoted to helping the people of Texas - to cover costs and maintenance for the first two years the Police Department and BearCom started assembling the pieces.
Firetide Inc., a California-based company, helped connect the cameras with 32 mesh nodes. These nodes link to one another wirelessly to form a network that connects all of the cameras. Should one link be blocked or lose power, the video signal will still go through without interruption, via another node.
"Without Firetide's wireless mesh, it would have been too difficult and cost-prohibitive to install the cameras where they were needed," said Jeff Murray, the project manager for BearCom, who oversaw the design and installation. "The mesh network forms itself, making installation even easier. It creates many alternative wireless links so the network is extremely reliable. Even if a wireless link is blocked or a node loses power, the video will always go through without any interruption in service."
With wireless devices common in the downtown area, Firetide had to avoid interference, so it used a special frequency licensed by the FCC only for public safety agencies.
The project also utilized services from
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