N.J. Turnpike Picks WiMAX Over LTE
December 01, 2010
Photo courtesy NJTA
Although public safety endorsed Long Term Evolution (LTE) as its future technology of choice, the New Jersey Turnpike Authority (NJTA) opted to deploy WiMAX technology for a statewide deployment along the two main highways — the New Jersey Turnpike and the Garden State Parkway. Pinnacle Wireless will operate as the systems integrator, and the deployment will use the Airspan HiperMAX platform to enable monitoring, control and communications along the two highways.
“What we want from the WiMAX system is fast, reliable, secure and cost-effective last-mile communications from the authority fiber backbone to the intelligent transportation system (ITS) equipment in the field,” said Senior Engineer Jose Dios, Technology and Administrative Services Department, NJTA. “We also expect to save money by eliminating NJTA operating costs for cellular services and outdated equipment.”
NJTA didn’t have to worry about the system being interoperable with the New Jersey State Police because the two entities share a dispatch center. Data collected by the system will be presented at the Statewide Traffic Management Center (STMC) in Woodbridge, N.J. The STMC allows state police dispatchers sit alongside operations personnel from the NJTA and the New Jersey Department of Transportation (DOT), and all three agencies’ networks converge in the building. Dispatchers and operations personnel from the agencies share the ITS data, which allows for interoperability without needing to align the same technology in the field.
“If there was an accident on a road in the state highway system and turnpike operations personnel wanted to look at a DOT camera run off LTE, they would just have to look across the room,” Dios said. “The STMC serves as a network hub for various communications architectures.”
With the collocated dispatch center, “everyday operations are aligned,” said Michael Hayford, president, Pinnacle Wireless.
The NJTA operates the majority of its data and voice communications over a fiber network that runs the length of both highways, 360 miles. Fiber drops are at every administration building, microwave tower, maintenance yard, toll plaza, service area and state police facility. Off the fiber nodes, various radio bands (450 and 900 MHz) and cellular leased lines communicate to roadside ITS devices. The data is brought back to the fiber network and then made available throughout the NJTA.
The authority decided it was time to replace the system for a variety of reasons, including that many of the components are no longer manufactured, and replacement parts are expensive, Dios said. Construction is under way to widen both interstates and involves tearing up both roads; the authority recognized that it was the ideal time to update the communications. “It can’t wait,” Hayford said. “The turnpike needs the communications today, not two to three years from now.”
The driving factor for a new communications system was the deployment of full-matrix, full-color signs and new IP cameras, which require larger bandwidth, Dios said. The statewide system’s main applications will include sign controls, closed circuit TV (CCTV) cameras, highway advisory radio (HAR), traffic detection sensors (TDS) and roadway weather information stations (RWIS).
The project began in 2008, when a communications study was conducted with comparing LTE, WiMAX, Wi-Fi, leased services, satellite, fiber optic, free-space optics and carrier current technologies.
In August, New Jersey won a $40 million federal grant to deploy an LTE public-safety network in the northern part of the state. “At the time [of the NJTA study], LTE was still evolving, and with pending installation contracts for over 220 color LED variable message signs, over 100 cameras, and thousands of detectors, timely deployment of wireless communications was critical,” Dios said.
NJTA considered bringing fiber to every node, but the associated deployment cost was estimated at more than $100 million, Hayford said.
Mesh networking, another technology considered, would require running power to each of the node points and a total of 750 nodes, Hayford said. If a driver is distracted and takes his/her eyes of the road, even momentarily, when the driver’s attention goes back onto the road, the car follows the eye’s gaze. The human eye naturally fixates on something large, which is why people will run into giant signs. “Populating the highway with 750 nodes is essentially 750 targets,” Hayford said.
There would have been additional costs for replacements and repairs if the nodes were hit. “Plus you’d need to drop power to many obscure areas and factor in the cost to maintain those 750 points,” Hayford said. “And since the nodes are lower to the ground, it wouldn’t provide coverage off the highway.”
WiMAX was eventually selected as the preferred technology because it offered many benefits NJTA was looking for, including features of the 4.9 GHz licensed public-safety spectrum and the availability of off-the-shelf products. The technology allowed the largest footprint of coverage and was cost effective and movable. Another benefit of WiMAX nodes was the ability to install them in existing communications shelters. The required 30 nodes can be placed 130 –150 feet off the ground, allowing for views of some off-highway areas, increasing visibility.
“The new WiMAX system, which incorporates orthogonal frequency division multiplexing (OFDM), increases radio reception coverage to challenging areas on the roadways and uses a protected 4.9 GHz public-safety band, which will offer full geographic coverage of both roadways,” Dios said. The technology will allow signs, cameras and other traffic control devices to be placed where they are best suited. “Previously, camera deployment sites were isolated to convenient line-of-sight locations, which were not necessarily optimum for traffic engineering or control,” he said.
The $6.5 million project will be completed by 2012 and will be paid for with general revenues, almost 90 percent of that coming from tolls. The rest will come from fiber leases, cellular tower leases, service area concessions and the operation of the PNC Arts Center, Dios said. At the end of 2009, the NJTA released a RFP, five companies responded and Pinnacle was awarded the project. The company designed the network, and provided design and topology, as well as delivery, installation and maintenance for two years.
The NJTA operates 30 communications towers along the highways, where the nodes will be installed. The systems will be powered by a new 48 VDC power system that is being deployed in parallel with the WiMAX system and will provide a minimum of eight hours and maximum of 24 hours battery backup run times, Hayford said. The WiMAX equipment will be integrated within a single rack assembly along with four other new systems being implemented by Pinnacle —RAD megaplexers, Brocade CES 10 Gigabits per second (Gbps) Ethernet switches, site monitoring system and DragonWave digital microwave system, he said.