WAI-WIZE has been awarded a contract to provide turnkey wireless services for ACS in support of the City of Dallas’s Photo Enforcement project. Specifically, WAI-WIZE provided design, installation, operation and maintenance services.

This new system would interconnect video surveillance cameras installed at intersections throughout the city that had a history of accidents or red-light violations. In addition, each approach into the intersections would be monitored. Initially, officials decided to install 60 cameras at 40 intersections in order to monitor a total of 60 approaches across the entire landscape of the city, which covers 225 square miles (362 km). As part of the “safe Light, Dallas Stops on Red” program, red light violation information was transmitted from the network of cameras and stored at a processing facility on a daily basis. As a result, a wireless backbone to backhaul all the data traffic was needed.
Another challenge for the city was that the locations of the intersections were dispersed across the city and connections needed to be made amidst many obstructions, such as trees and building, and over one long-distance link of 10 miles.

Technical Requirements

• Secure reliable connectivity in highly congested city environment
• High bandwidth, data rates of up to 1 to 3 Mbps each way
• Rapidly deployable with minimal disruption to traffic and infrastructure
• Interference mitigation in a mostly non-line-of-sight (NLoS) cityscape
• Reliable backhaul of all data traffic from network of 60 cameras
• Leverage existing infrastructure for communications installation

Deployment Detail and Interoperability
Given the tight deadline, ACS decided to contract with WAI-WIZE to design and deploy a broadband wireless network instead of DSL. ACS recognized that fixed wireless provided a more reliable infrastructure, required less time to implement and cost less to purchase and deploy. To handle the data communications element of the new red-light enforcement program, WAI-WIZE deployed 140 of Motorola’s MOTOwi4 fixed Point-to-Point (PTP) 58400 Ethernet bridges with integrated antennae.

The first order of business for WAI-WIZE was to establish a communications backbone in order to manage all the traffic from the 60 camera system. To do this effectively, a ring topology was built around the city in order to handle the backhaul. Happily, Motorola's wireless topology met the requirement from the city to minimize the distance to and from each intersection and the nearest communications tower, which ranged from three to seven miles (5 to 11km).

After the backbone was established, the team started to bring each of the intersections online and linked the towers together, some of which were about 10 miles (16 km) apart. In fact, the MOTOwi4 fixed point-to-point Ethernet bridges on the water towers were linked together to provide redundancy for the wireless network. All of the intersections were dispersed throughout the city and the signal had to overcome high rise buildings and tree obstructions that were prevalent across the congested metropolis. As a result the radios needed to be positioned at least 25 feet (nearly 7 meters) above the intersections. Given the height of the radios and the common occurrence of storms in the Dallas region WAI-WIZE installed lighting arresters to further ensure connectivity even in inclement weather.

Results
The City of Dallas was able to leverage wireless technology to accomplish community goals, while keeping costs low. The Motorola MOTOwi4 PTP 58400 Ethernet bridges have been able to interconnect all the cameras in the city red-light violation system as well as overcome areas of high interference and obstruction to deliver the data to the main processing facility downtown. Furthermore, the reliable backbone that was built to handle the data backhaul traffic is operating flawlessly. To date, 40 of the 1,300 intersections in the greater Dallas area now have red-light photo monitoring.

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