All Aboard
The Department of Homeland Security was also involved in funding the mesh project for the San Diego North County Transit District. The DHS grant was to harden security at bridges, grade crossings and so on, largely because the I-5 interstate is the main corridor between Los Angeles and points south. The mesh network, managed by contractor Datel Systems, was installed along the 42-mile-long commuter rail that runs between Oceanside and San Diego, using 802.11g wireless connectivity within right of way and at all train stations for work crews. "It’s quite a challenge to keep a VPN connection on a train going 80 miles per hour," commented Datel’s Larry Piland.

There’s a security command station at the first rail station and the start of Coaster commuter rail line, with no other viable infrastructure in the right of way (no power, no telecommunications). Datel ended up mounting its own poles with solar panels, though that’s still problematic; on the coastline, Piland said, they’re lucky to get four or five hours of full sun each day.

Using CCTV (analog video) equipment, security personnel can watch the bridges and other vulnerable sites; that’s not trivial, given that college kids like to party in such remote locations, and one bridge was set on fire during a beer bash. The project has successfully demonstrated mobile mesh with rail vehicles at 90-plus mph, and seamlessly integrated with existing CCTV infrastructures. The mesh network was designed for security requirements but, Piland explained, is flexible enough to handle commercial, telemetry and customer amenity needs.

The role of wireless municipal networks is also being expanded by police forces. One obvious benefit of this technology is its ability to improve communication between personnel, such as during a concert in Lakeland, N.J. In the community’s pilot project at a music festival in September 2006, explained Patrolman Robert DeSimone, the small police department improved traffic flow and gave the event commander the ability to view the entire event from one location. In their case, the Wi-Fi access points are mounted on top of the patrol cars, so officers can use instant messaging, license tag identification and video capture (which also helps for a "video lineup" in which a suspect is shown to a robbery victim: "Is this the guy?"). "It’s saving us money, and letting us provide better protection," said DeSimone.

The police department in Rockland, Ill., is also using cameras with a mesh network—in a much more dangerous area. Using a grant from the Department of Housing and Urban Development, a 2,000-unit housing project with a crime history is now being monitored over the Internet. The 16 IP cameras—mounted in a bulletproof enclosure with the wireless mesh nodes, flashing police light and backup battery—create a visible deterrent for criminal activity and give the local police force a mobile video system. This also puts in place the infrastructure to provide free Wi-Fi access for residents.