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The next generation of wireless communications for Water Utilities
For many years now, private narrowband wireless systems and carrier-based leased-line services have played a critical role in establishing data communications for water and wastewater management systems. However, with the elimination of commonplace communications networks such as frame relay systems and the introduction of new industrial sensor technology and powerful low-cost edge computing devices, these legacy wired and wireless networks require an upgrade.
Until recently, communications options for industrial operations have been scarce, as many existing solutions face challenges in addressing the capacity, security and reliability demands of water and wastewater management operations. Unlicensed wireless technologies have proven to be poorly designed for wide-area field networks, and commercial wireless networks have proven to lack the necessary security and reliability for mission-critical applications. Furthermore, commercial telecommunications service providers continue to abandon their legacy copper networks in favor of fiber and coaxial cable without addressing the remote locations of industrial assets.
To address the limitations of legacy wired and wireless communications solutions and the additional weaknesses of commercial service providers, new wireless standards backed by key industrial and utility leaders are emerging. With these standards, including the new IEEE 802.16s industrial wireless standard, utilities have a secure, high-capacity, reliable communications protocol to rally behind, as well as a framework for establishing smarter wide-area networks.
Water and wastewater utilities (like most other utilities) are at a crossroads, particularly with their data communications networks. Until recently, many relied upon frame relay systems from AT&T, Verizon and Sprint. However, in 2016, these systems were completely phased out without good alternatives. The termination of this service came at a time when service and reliability concerns of carrier-based wireless networks had been raised due to prolonged outages from man-made and natural disasters. Also, with the advent of new sensor-based technology, increased upstream throughput also had become of interest. While historically serial-type data rates of 9.6 kilobits per second were adequate, new IP-based applications will require a substantial boost in upstream throughput.
The remaining communications options that exist today all have significant constraints. Those solutions include narrowband wireless, cable modems, cellular modems, digital subscriber lines (DSL), fiber lines, satellite and unlicensed radio networks. Choices are further minimized when water utilities consider the deterioration of wired legacy landlines, which do not provide the remote connectivity required in certain service territories. For this reason, wireless data network technology and infrastructure must carefully be considered as a solution to meet existing and future communication demands as we see increased automation and wireless connectivity.
To keep up with the changing technological landscape, some water utilities have adopted unlicensed Wi-Fi-based technologies or wireless commercial carrier-based services for their industrial-grade data communications. However, in selecting these options, certain critical industrial requirements have fallen by the wayside.
Unlicensed radio networks, by definition, are low-power radios that must accept interference from others. They are not designed for wide-area critical deployments, but instead for limited-range use. Furthermore, they are susceptible to a variety of security threats and rely upon collision-based protocols that make their data rates and performance unpredictable for wide-area networks.
Commercial cellular data networks— such as those offered by AT&T, Verizon and Sprint—are sometimes utilized due to their convenience factor. However, these networks fail to meet many of the critical security and reliability needs of utilities. Man-made and natural disasters, such as hurricanes Harvey and Irma in 2017 and Hurricane Sandy in 2012, can render commercial services useless for unpredictable amounts of time. Furthermore, decisions about the restoration of tower sites and network functionality are made by the network service provider, not the utility. Given their recent experiences with major hurricanes, many government entities have begun to mandate communications mitigation plans under the assumption that public networks will continue to experience periods of sustained outages.
Commercial wireless networks also leave the mission-critical network exposed to a variety of security threats, including denial of service attacks on the carrier network and even targeted attacks on a specific utility asset. Capacity also is contention-based in consumer wireless networks in both the upstream and downstream. Carrier networks are purposely designed to limit upstream capacity and maximize downstream capacity for video and streaming. Utility networks tend to be upstream-focused, where data is pulled back to the operations centers.
To remotely monitor and control both pump stations and combined sewer overflow stations and to ensure continued communications and data storage between supervisory control and data acquisition (SCADA) systems and remote terminal units (RTUs), Distributed Network Protocol (DNP3) often is used over these unlicensed and public networks. In situations where network connectivity is slow or intermittent, DNP3 allows water and wastewater utilities to store data in an RTU before communication reestablishes and it can send data back to the main SCADA system. The challenge is that the DNP3 configuration can be complicated to set up between SCADA and RTUs, and is difficult to maintain for many utilities. The emergence of new reliable private licensed network systems, however, is making it possible for utilities to maintain continued connectivity without requiring the DNP3 protocol.
To address the security, capacity and reliability shortcomings of unlicensed and commercial wireless networks, the Institute of Electrical and Electronics Engineers published a new standard for private licensed wireless field area networks in October 2017. The standard, known as 802.16s, was developed with the support of the Electric Power Research Institute, the Utilities Technology Council and a group of major U.S. utility companies. The standard was designed to offer utilities a substantial capacity increase from legacy narrowband wireless solutions and to fill in the gap created by the abandonment of frame relay and other wired networks by commercial telecom providers.
The need for secure and reliable distribution of electricity made the electric utility sector a perfect industry to develop and test the standard for use in other industrial sectors. Now the adoption of the standard is expanding beyond the electric utility industry to a broad range of industrial and utility applications including the oil and gas industry and now the water and wastewater industry.
The standard enables the use of any licensed radio frequency in the VHF or UHF bands, provided there is a minimum of 100 kHz of contiguous spectrum. The standard’s flexibility in channel size and frequency created a large number of legacy frequency bands that can be acquired or leased by the utility at a low cost. The acquisition of licensed spectrum becomes economical given the lower infrastructure costs. Tower costs and backhaul for unlicensed networks more than overwhelm the cost of the spectrum. Given the power limitations of unlicensed wireless technologies, infrastructure costs can balloon to 100 times the cost of using a licensed band.
Unlike commercial 4G/LTE networks from major service providers, these closed-loop private network systems are designed to create a digital and physical separation from the public internet keeping critical data communications on a separate network to ensure reliability and security.
The radio frequencies for 802.16s are available from the Federal Communications Commission on a site license basis or can be purchased for exclusive use in the secondary frequency markets. Some utilities may choose to purchase the frequencies outright and establish their own communications network, which ensures it is built to exact capacity needs, grants full ownership and control, and mitigates risks associated with consumer traffic. As an alternative, water and wastewater utilities that lack the resources to own and operate a network can choose to join a managed private licensed wireless network dedicated solely to industrial operations. With both of these options, network prioritization is ensured following a natural disaster, and security risks are minimized.
With the recent completion of the new 802.16s standard and the availability of licensed radio frequencies that leverage the standard, water and wastewater utilities no longer have to default to less secure unlicensed or carrier-based networks.