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The Greater Harris County (Texas) 9-1-1 Emergency Network (GHC), which now works on a converged IP and microwave system, provides service to two counties and 49 cities, including Houston, serving nearly 50 PSAPs.
The Greater Harris County (Texas) 9-1-1 Emergency Network (GHC) provides services to both Harris and Fort Bend counties, and 49 cities, including Houston — serving nearly 50 PSAPs. To advance communications, local officials wanted to move GHC toward a Next Generation 9-1-1 system with an Internet protocol (IP) backbone to serve all the PSAPs.
Harris County and Houston were planning to upgrade their radio systems simultaneously to achieve broader coverage and switch to digital systems for greater interoperability. Area leaders realized they would benefit greatly from sharing a broadband infrastructure, sites for towers and other equipment if they converged the systems for GHC, Houston and Harris County onto one digital system with a multipurpose backbone.
Sharon Counterman, GHC deputy director, says, “Early in the GHC project, it became clear to management and our board that there were opportunities to work with both the city of Houston and Harris County to provide a multi-use system across a wide area, share bandwidth and contain costs by not duplicating equipment and towers.”
With this approach, the agencies would be able to share maps, information, analog and digital capabilities, as well as transport radio communications across municipal and county lines, and reduce overall equipment costs.
PSAPs within GHC already had individual IP networks that needed to be upgraded and tied together to produce an area-wide interoperable system. While considering this challenge, planners had the foresight to include a fully redundant microwave-based backup system that could assume any or all functions if a disaster were to strike the primary network.
Working alongside its longtime communications technology consultant, L.R. Kimball, in 2008, GHC set out to develop a high-level strategy study to recommend what facilities and equipment to incorporate into the IP network.
After a thorough vetting of suppliers, GHC worked with L.R. Kimball to begin deploying its new system. The team followed a conceptual layout based on bandwidth and locations, along with requirements for each site and tower to be incorporated.
Under the plan, Houston and Harris County provided their existing tower sites and radio equipment, while GHC provided dishes and equipment boxes. Now, only one dish is required on each tower instead of three separate dishes. The towers will be linked, and calls will be distributed to the right public safety department within the network.
Creating a fully redundant, active and load-bearing microwave system was an unprecedented endeavor. Multiple pathways, a Sonnet ring and 3G fill-ins provided backup and allowed GHC to balance the load between the IP and microwave networks.
With its IP backbone, the new network furnishes much better coverage than the systems it replaced because the collective, interlinked towers create a larger footprint. No new towers needed to be built because a single dish can handle radio, data and phone traffic in the converged digital radio and digital telephony IP network.
“Houston is the fourth largest city in America, and we are subject to bad weather including hurricanes,” says Counterman. “It is imperative that GHC [does] all [it] can to provide 9-1-1 across a large area of over 4 million citizens. When help is needed, our 9-1-1 system must be available. The new microwave system provides one more piece of the redundancy pie, and the fact that we could do it jointly with the city and county allowed for a larger, more robust and cost effective opportunity.”
The system has not yet gone live, but is scheduled to by the end of this year. The GHC 9-1-1 Emergency Network is well on its way to a seamless, countywide communications system that provides interoperability among all the public safety departments within its coverage area.
About the Author
Roxann Brown is market segment lead for L.R. Kimball.
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