The Age of Wireless

Securing critical infrastructure is not a walk in the park in rugged terrain

Government agencies overseeing national and local parks and municipal and private utilities -- including water and wastewater -- have remote communications and physical security requirements that are often challenging to address. Connecting multiple distant sites at speeds equal to those achieved over wire is a daunting proposition but is necessary when fiber or leased lines are too costly or impractical. The needs are pressing when an act of crime or vandalism, an environmental disaster, or loss of communications can potentially cost millions of dollars to mitigate and even cause the loss of lives.

With that in mind, two different cases, one in Southern California’s Otay Water District and the other in the vast Four Rivers Dam area of South Korea, are great examples in using the flexibility, capacity and reliability of wireless mesh in extremely challenging geographical areas to provide SCADA, utility security, video surveillance for dams, sensor data networks and Internet services.

The Otay Water District Challenge
The Otay Water District has a 125-square-mile service area and more than 200,000 customers. Many of its 50-plus remote facilities, including reservoirs and pump/hydro stations, are in isolated and sparsely populated areas. Options for getting land-method communications to these sites -- T1, DSL or cable -- were cost-prohibitive, with some bids coming in as high as $100,000 a month.

The wireless mesh network offered Otay an economical and easy way to provide reliable connections and video surveillance between its headquarters and remote facilities. Besides the cost savings, the system delivers real-time security feeds rather than dialon alarm, and real-time access control information rather than daily dial-up. The high-capacity network also provides the ability to use multiple cameras at a site. In the past, much of Otay’s SCADA infrastructure included periodic dial-up or dial-on-alarm situations.

Having the real-time SCADA information is critical during main breaks, valve closures and other pressure-monitoring situations. Finally, the district is now able to have Wi-Fi access at its sites rather than relying on cellular broadband connections.

The initial phase of the deployment, to test the performance of the MIMO wireless mesh backbone, connected four sites. Otay’s headquarters, recycled water treatment plant and two nearby water storage reservoirs are separated by a high ridge line; because of line-of-sight issues, the network uses linear mesh topology (daisy-chaining) and loops back to connect the final site, with the longest link spanning 2.3 miles and shortest link covering .5 miles. This initial network uses dual-radio HotPort 7000 MIMO mesh nodes operating in a combination of 5 GHz and 4.9 GHz frequency bands. The overall capacity end-toend is 100 MBps. Twelve sites have been completed, and the entire proposed network will connect more than 50 sites.

“We’ve achieved real speeds in the 100 MBps range utilizing 802.11n technology and created a mesh point-to-multipoint design that has exceeded our expectations,” said Bruce Trites, Otay Water District’s network engineer.

The system uses a redundant mesh design for the WAN backbone with MIMO mesh technology, and point-to-point design using a 900 MHz frequency band for non-line-of-sight and near-line-of-site links.

Link distances in the overall deployment will range from .3 miles to 3-plus miles.

For some of its well and booster stations where trees make it impossible to use the frequencies in 5 GHz, the system will use the HotPort 6200-900 non-line-ofsight mesh. These dual-radio units have one radio at 900 MHz and one radio at a higher frequency. The 900 MHz links connect well sites and reservoirs at lower elevations to “hub” nodes located at higher elevations.

Once the 900 MHz link reaches the reservoirs, the second radio on the mesh node uses the 5 GHz frequency to send the data back to the control center.

The combination of 900 MHz and line-of-sight 5 GHz bands is often the best solution for utilities, which must deal with vegetation and a variety of topographies.

Many utilities have access to a 4.9 GHz public safety band, so 4.9 GHz communications also can be incorporated into the design.

South Korea’s Billion-dollar River Restoration Project
To preserve the environment and prevent disasters caused by flooding, the South Korean government is undertaking a $2 billion restoration project of the country’s four major rivers -- the Han River, the Yeongsan River, the Nakdong River and the Seomjin River -- and surrounding recreational areas. Funded by the government, South Korea’s Water Resource Management Corporation has selected Daelim I&S, the country’s fourth-largest system integrator, to deploy wireless infrastructure solutions for the Four Rivers restoration project. When completed in 2012, the multi-service wireless infrastructure will provide a sensor network for water level, temperature and pollution measurement, a video surveillance network to monitor the dams and public Wi-Fi service for adjacent riverside parks.

Combined, the four major rivers are more than 240 miles in length. To cover this area, more than 200 Firetide MIMO and non-MIMO mesh nodes, along with 300 cameras from Sony, Axis and Samsung, will be deployed to support the sensor and video surveillance applications. In addition, free public Wi-Fi service will be provided in adjacent parks using MIMO-based wireless access points and customer premise equipment.

“We selected a high performance, multi-service wireless network infrastructure capable of reliably covering a large area and securely supporting the concurrent transmission of real-time video, voice and data,” said Song Choong II, the Four Rivers Restoration project manager for Daelim I&S. “We were impressed with the vendor’s experience, knowledge and track record in providing wireless infrastructure solutions for many demanding applications such as the Seoul subway and other ‘ubiquitous city’ projects throughout South Korea.”

The wireless mesh technology being used in the Four Rivers project has also been deployed in other South Korean wireless remote projects and video surveillance projects in the country. In fact, a wireless infrastructure mesh network is being used as the backbone in South Korea’s “u-City” government-supported programs to bring ubiquitous digital services to residents, tourists, employees and businesses of South Korean cities.

Both the Four Rivers and Otay examples illustrate the convergence of voice, video and data services over a remote wireless network system. This convergence is expected to grow, so it will become increasingly important for government agencies, utilities and others in charge of deploying remote networks to make sure they select a reliable wireless solution capable of supporting high-speed remote connectivity today and real-time, multi-service applications as they continue to evolve.

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