Remote-site data transmission deflects regulatory runaround

Since 1848, the city of Georgetown has been found about 30 miles north of Austin, the Texas state capital.

Yet the town’s population has almost doubled, to 52,000, in the last 12 years.

Workers and dependents from major Austin employers ¾ including the state government and University of Texas, and scores of high-tech companies, including Dell, Apple and Intel ¾ are among those responsible for the growth.

All these people need water and sewers and electricity and roads.

That’s where Georgetown Utility Systems, a department in the City of Georgetown’s municipal government, comes in. The pace of growth makes providing services a tall order, says Ron Marrow, a Georgetown transmission and distribution supervisor.

"It’s not enough to just ‘keep up’ with the city’s growing number of citizens, because that would mean we’re always behind the curve," he says. "We have to stay ahead of the growth and that takes good planning."

Marrow and a team of three have charge of communications and connectivity across the municipality’s water, waste and electrical infrastructure. In their endeavors, they bring to bear a wealth of experience with the city’s infrastructure and its environment.

Fast look back

For years the utility used the 900 MHz radio spectrum in monitoring components in its water, sewage and electrical distribution systems, i.e., using SCADA data communications with speeds of 9600 its/sec. However, Marrow says, the 900 MHz radio communications weren’t always reliable ¾ given an approximately 300 square-mile coverage area.

Hot weather was an especial problem. The area is known for long, hot summers. Average temperatures often top 100 degrees F in July and August. Temperature highs near 90 degrees are common well into October.

A seemingly trivial temperature-related failure can have significant consequences.

"Heat-caused atmospheric changes can disrupt radio data transmission," Marrow says. "Whenever it got hotter than 90 degrees, for example, communications from a remote wastewater lift station would fail. We’d send a technician to take data readings every four hours. If there was an overflow, the actual environmental impact might not be all that big, but the regulatory reporting would be huge, so we’d make sure someone monitored it in person."

Another issue was the star topology of the 900 MHz radio network. “All the remote radios transmitted back to one central radio," Marrow says. "If that central radio went down, so would all our communications."

Big step taken

Marrow and his team designed, developed and deployed a redundant, 1.0 Gbps fiber ring network for the city’s SCADA communications. Its multi-megabit bandwidth eventually would enable broadband communications that include video surveillance, voice-over-IP and remote, on-demand WiFi hotspots for municipal field workers.

In the aftermath of the project, however, their most immediate concern was cost-effectively connecting remote water treatment stations with the new fiber ring.

Installation of in-ground fiber can cost up to $25,000 per mile. Extending the city’s fiber to its wastewater lift stations, up to seven miles away, wasn’t economically feasible. Instead, broadband wireless would be used to extend the municipality’s fiber ring multi-megabit throughput out to the remote sites.

Alternative options for doing so included using 1) a commercial cellular network, but that came with monthly charges; 2) 802.11 WiFi, but that came with limited range; and 3) 802.16e WiMAX, using the 4.9 GHz spectrum that the U.S. Federal Communications Commission (FCC) allocated to public safety and municipal uses, and which also allows for mobile connectivity.

While WiMAX over the 4.9 GHz band delivers the range needed, it requires FCC licensing, something which isn’t done without expert support. This is where Siemens reengaged with the municipality.

Devising devices

Deploying the municipality’s fiber ring included installation of "scores" of Siemens RUGGEDCOM RS900G Layer 2 switches. RUGGEDCOM is Siemens’ harsh-environment communications portfolio. The RS900G is an environmentally hardened, fully managed Ethernet switch that provides dual-fiber optical Gigabit Ethernet ports with Gigabit uplink ports, and 128-bit encryption.

In all, Georgetown had more than 200 RUGGEDCOM devices deployed in its fiber network, including routers and media converters. "It only made sense to keep all the iMAX components in the family, too," Marrow says.

Marrow’s Siemens’ contacts understood what was involved in extending the fiber ring’s broadband throughput to the remote sites. WiMAX technology also presented some line-of-sight challenges in connecting wastewater lift stations ¾ typically placed in low-lying areas ¾ amid Georgetown’s rolling, tree-covered terrain.

"We not only needed help securing our FCC license, we also needed some excellent RF engineering, system design and integration," Marrow says.

Integrator introduction

For these services, Marrow contacted Alpha Omega Wireless, an Austin-based systems integrator and Siemens-certified industrial wireless solution provider. Marrow met with Joe Wargo, founder and president, and Kelly Ice, business development manager.

Alpha Omega Wireless compiled requirements to define a point-to-multipoint 4.9 GHz WiMAX solution as well as a comprehensive deployment and commissioning plan. In addition, they processed the paperwork needed for the city’s FCC license to use the 4.9 GHz spectrum.

The solution includes three components, all with rugged performance features to withstand harsh weather conditions: the WIN 7249 small form-factor base station, for 4.9 GHz radio transmissions; the WIN 5249 outdoor subscriber unit, also for the 4.9 GHz spectrum; and the RP100 single-port 802.3xx Power-over-Ethernet (PoE) injector, which powers the other two devices.

The utility-grade gear works in environments subject to high electromagnetic interference (EMI), extreme temperatures and environmental pollutants. It’s also been put through accelerated-stress testing, including highly accelerated life testing (HALT) and highly accelerated stress screen (HASS), both designed to find defects before environmental conditions do. These tests enable Siemens to provide five-year warranties for the RUGGEDCOM portfolio of network components.

Today, Georgetown enjoys a reliable, future-ready, high-bandwidth wireless network. Its developers claim thousands of dollars in labor cost-savings along with hundreds of thousands of dollars in cost-avoidance for just the first deployment phase, which took just two days.

The base station was installed in one of the city’s outlying, 120-foot water towers. It delivered a clear line of site to subscriber units installed at four water-treatment stations, the farthest more than five miles away.

What followed was faster

Marrow says he was amazed at the difference in transmission speeds apparent when he used his laptop to log into the 4.9 GHz SCADA data stream. "It was like night and day," he says. "Before, the data speeds were so slow. It’s like going from a pipe a quarter-inch wide to one that’s six-inches wide."

Marrow was pleased with the implementation by Alpha Omega Wireless, backed by Siemens service and support.

"We test all the radio components as soon as they arrive to ensure each one works to its specification," says Ice. "Then we follow our proprietary project management methodology, which we built on the rigorous standards of the Project Management Institute."

The city no longer need dispatch a technician to hand-log data at wastewater lift stations whenever outdoor temperature breaks 90 degrees, as it does more than 30 times a year. That saves thousands of dollars.

It pales though in comparison to the city’s avoidance of hundreds of thousands of dollars in capital costs, if it had pushed fiber out to the remote sites.

Siemens and Alpha Omega Wireless had the expertise, responsiveness and consultative approach right for the project. "They worked well together and the support was good," he says. "Throughout it all, we felt our backs were covered. No matter what issue might arise, we knew both companies would respond as one."