JPS adds advanced trunking capability to P25 platform

Aug 4, 2008 10:10 AM, By Glenn Bischoff

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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.”