JPS adds advanced trunking capability to P25 platform
KANSAS CITY—Raytheon’s JPS Communications has added composite channel trunking to its P25net Project 25-compliant, digital, trunked radio communications system—a capability that is expected to trim infrastructure costs for users by reducing the number of repeaters that have to be deployed.
According to Rick Summers, a JPS program manager, a typical trunked system employs a minimum of three repeaters: one supports a control channel that is on all the time, while the other two are for talk channels. With composite channel trunking, a single channel is used for talk and control; the control channel switches into talk-channel mode whenever the system receives an authenticated signal.
“When you don’t have much loading, a single channel is all you need,” Summers said.
Reducing the number of channels has a corollary benefit: it reduces the amount of spectrum that’s needed to support operations. The combined cost savings from these reductions are especially advantageous in low-population areas, where it is more difficult to cost-justify investment in infrastructure and spectrum resources, because such areas are visited much less frequently by field technicians.
Given its sparse population—3.5 million residents spread over 256,000 square miles, or 14 residents per square mile—the province of Alberta, Canada, would appear to be the ideal place for composite channel trunking. “They have very few people … so the loading is going to be very light in most areas,” Summers said. Indeed, JPS recently received a $5.4 million contract from ATCO Electric, which provides power throughout most of the province. JPS will deploy its upgraded P25net platform for the utility’s 80-site system.
Reducing the number of repeaters needed for the system was an important factor in winning the contract, Summers said. “They had a cap on funding and [we] came in very cost-effective.”
Once the new platform is in place, all of the sites throughout the province will be interconnected to deliver interoperable communications between all offices and divisions. Previously, the utility had problems communicating between sites, because the previous system employed single-site VHF repeaters that weren’t connected, Summers said. “People at one site didn’t know what was happening at other sites during a power emergency.”
In addition to P25net, the ATCO solution includes a mobile data system developed by Advanced Digital Systems that will be used for workforce management, primarily to dispatch field technicians, Summers said. The solution also will employ mobile UHF-to-VHF repeaters in vehicles to improve coverage for portable radios that previously had been poor, Summers added. The in-vehicle repeaters interface to the P25net platform.
In addition, the P25net platform will interconnect to ATCO’s internal Cisco phone system, as well as the public switched telephone network, which will be a boon for field technicians, according to Summers. “If they roll up to a house, and it appears the customer isn’t home, they can call the customer on the telephone,” using either their mobile or portable radios.
The system is easy to upgrade and expand, according to Summers. “All you have to do is add a repeater, a channel card and a little programming to let the system know the channel card is there, and you’re up and running,” he said, adding that “you can add a trunking channel in a couple of hours with our system.”
Summers said the P25net platform lets customers seamlessly migrate their systems from analog to P25 operation. “You just have to upgrade the subscriber units and execute a configuration change at the softswitch,” Summers said.
While a $5.4 million contract might not seem like a big win, it represents a significant milestone for the P25net platform, because of the number of sites involved in the deployment, which is scheduled to begin in the fourth quarter, with completion expected my mid-2009, according to Summers.
“It shows that our P25 infrastructure can be used for larger deployments,” Summers said, adding that P25net was tested in Alberta in January and performed well. “We’re feeling comfortable that it’s a solid platform.”
