Mixing smartphones, radios gives new life to dispatch system

The San Luis Obispo County, Calif., Sheriff’s Department this year replaced its end-of life radio dispatch system with a digital IP platform that links commercial smartphones with its traditional land mobile radio network. From a PC console, dispatchers are able to click and drag smartphone users into talk groups on any available frequency, giving them push-to-talk radio functionality anywhere they have cellular coverage.

“It’s a whole new level of interoperability for us,” said Under Sheriff Tim Olivas.

The system, built on the Raytheon interoperability gateway and the WAVE Dispatch Communicator and Mobile Communicator software from Twisted Pair, not only enables communication between departments that traditionally have used siloed radio systems, it also extends radio coverage in rugged terrain. Using standard servers and PC consoles with existing Internet connections, the cost of maintenance and upkeep is less than with a traditional system, Olivas said.

San Luis Obispo County’s effort is part of an emerging trend of using IP technology to upgrade traditional public safety communications systems that are showing their age.

At the national level there is an effort, named FirstNet, to establish a nationwide dedicated IP backbone for first responders that would link local and regional systems that today do not communicate with each other. It will take years and billions of dollars to get FirstNet into place, but the underlying interoperable technology is available now, said Mike Bostic of Raytheon’s Civil Communications Group.

“The reality is it already exists,” Bostic said. “It just isn’t designated for public safety.” So, first responders increasingly are using ad hoc hybrid systems that combine consumer technology and dedicated public safety systems. “For the most part, cops and firefighters use their cell phones more than their land mobile radios because they do so much more,” he said.

Raytheon, along with Cisco, Mutualink and other companies in the public safety market are formalizing these ad hoc systems with IP gateways that link cellular and other digital communications with legacy radio systems, creating a single, seamless network.

The results are not perfect. Commercial cellular service is not as robust or as secure as a dedicated public safety network. But they are practical, can extend the capabilities and range of legacy systems, and because they are based on off-the-shelf hardware they can be more economical to deploy and maintain.

“This is a supplemental part of our system,” said Sheriff Ian Parkinson. “It is not designed to replace the radio system.”

The decision to adopt an IP platform and extend radio coverage with cellular service was driven by a combination of geography and economy. San Luis Obispo County, located on the Southern California coast midway between Los Angeles and Monterey, is a rural area with lots of mountains and hills.

“With radio, we rely on repeaters,” fixed point transceivers that pick up and relay radio signals, Parkinson said. “We’ve placed as many as we could over the years, but we still have a significant number of areas with poor reception.”

The county is covered by a robust commercial cellular system that provides better signal quality and reception than the radios. It also is completely separate from the police radio system. The opportunity to link the two came about because the existing dispatch system was due for replacement.

“The Orbacom system had reached its end of life,” Olivas said. “We were sitting on obsolete equipment.”

Orbacom was a leader in dispatch communications systems, but it was acquired by another company in 2004 and support for its products had ended by 2009. “We went several years beyond end-of-life,” Olivas said. “We got our money’s worth out of it,” but it was now being patched together with parts purchased on eBay.

The county had no replacement plan for the system, which in retrospect was something of a blessing, Parkinson said. With no replacement plans in place, the county was able to take advantage of emerging technology.

The county did not want to get too far ahead of the technology curve, however. Dependability is a necessity for public safety systems, and the evaluation team assumed at first that it would be getting a traditional, proven radio-based system for the dispatch center. They were impressed with the IP solution put together by systems integrator Raytheon, but had reservations. Raytheon was a major defense contractor but was not well established in the civilian public safety market.

The advantages of going to IP eventually won them over, however. Not only would it extend coverage of the existing radio network, but putting the system on off-the-shelf servers would be simple and would allow the county to easily deploy satellite and mobile communication centers for emergencies. “That was a big plus for us,” Olivas said.

WAVE Mobile Communicator is a mobile app for Android, iOS and Windows Mobile devices. Once downloaded to a smartphone it is enrolled by the system administrator, who assigns channels that each user is allowed to access. A touch-screen button allows push-to-talk over the digital cellular connection, which goes to the Dispatch Communicator console. Raytheon’s gateway links the console with the land mobile radio system, routing the cellular traffic to the appropriate RF channel, effectively putting everyone on the same system regardless of the handset being used.

San Luis Obispo has a designated radio channel for the sheriff’s department and channels for each of seven municipalities and two university campuses in the county, as well as a common channel all departments can use. Using a point-and-click interface, a dispatcher can create talk groups on different channels on the fly. Users of the Mobile Communicator app can talk on any designated channel and still monitor activity on the home channel, which is not possible with a radio handset.

The digital system does not yet support all of the features intended to be on a national IP network, such as video, data and collaboration, and the county has no intention of doing away with its land mobile radio system in favor of smartphones. But, the new system is superior in interoperability, mobility and coverage area than stand-alone legacy radios, Parkinson said.