The Case for Private Long-Term Evolution Networks
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- Aug 25, 2020 3:30 pm GMTAug 21, 2020 11:13 pm GMT
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This item is part of the Special Issue - 2020-08 - LTE Networks, click here for more
Two-way radio communications have been the standard for mission-critical wireless communications for nearly a century. The land mobile radio (LMR) systems of today are highly evolved and are very capable of providing reliable and secure mission-critical communications. However, these LMR systems have significant drawbacks. They are highly complex and expensive to deploy. The radio frequency (RF) spectrum in which they operate is crowded. And their ability to perform high-throughput data communications is almost entirely lacking.
The last drawback is particularly vexing for electric-power utilities. The critical nature of electric-power utilities has long been recognized and most are continually improving reliability in many areas. Critical needs for robust and efficient data-communications networks have emerged as utilities pursue increased reliability of electric-power delivery in their fast-changing environments. These include the smart grid, digital transformation, distribution automation, and advanced meter reading. New challenges have emerged as well, related to the quickly growing renewable energy sources, the expected exponential growth of electric vehicles, and new forms of energy storage.
There are also practical day-to-day factors that must be considered. For instance, let’s say that during a storm a tree falls, and in the process downs electric-power lines. In such a circumstance, the ability to remotely turn off power to those lines from a control station located miles away, within milliseconds (ms), potentially will save lives and/or hundreds of thousands of dollars in equipment damage and labor.
All of these opportunities, challenges and factors have one thing in common—they require broadband communications capabilities to handle the vast volumes of data that will be gathered, transmitted and processed, and to deliver the ultra-low latency demanded by some applications. Narrowband LMR systems are ill-suited to meet these needs.
Now, however, strong evidence is emerging that private Long-Term Evolution (LTE) networks might be the solution, buoyed by a recent decision by the Federal Communications Commission (FCC).
On May 12, 2020, the FCC ordered reconfiguration of the 900 megahertz (MHz) business industrial band to allow broadband operations—such as LTE—in what traditionally has been allocated for narrowband communications. The new rules divide the band, with 4 MHz set aside for incumbent narrowband operations and the remaining 6 MHz made available for broadband operations. The latter spectrum is licensed to Anterix.
While this decision will require a rebanding effort—i.e., relocation of narrowband LMR users to other frequencies—it also clears the way for electric-power utilities to deploy LTE networks in that attractive band.
LTE is a truly integrated voice and data technology, suitable for all kinds of demanding applications, from short messages all the way through high-quality video. Because the inherent latency is low and can be controlled, there are indications that the technology is suitable for even the most sensitive situations. In last year’s tests at the National Renewable Energy Laboratories, latency below 30 ms consistently was achieved, even with high traffic volumes.
Standardization of LTE networks permits reasonably priced and power-efficient chipsets that enable wireless devices to be manufactured to provide high throughput suitable for the widespread deployment of the Internet of Things (IoT). LTE networks are able to mix both high- and low-level densities of devices— making it feasible to install sensors and modems on individual utility poles to monitor and report network integrity. Large electric-power utilities are responsible for thousands of poles that support cables and equipment, the status of which is important to isolating faults that may interrupt service.
Due to the robust schema used for their over-the-air protocol, LTE networks provide a high level of interference resiliency. Adaptive modulation schemes allow the information flow to continue, albeit at a slower rate, in the face of interference or network congestion. While the information flow may slow, it is unlikely to be completely interrupted.
LTE has a very impressive list of advanced features, giving it unparalleled functionality and flexibility regarding quality of service (QoS)—including priority and preemption—advanced mobility, and scalability —from a single station (eNodeB in LTE jargon) to very wide area networks.
Finally, LTE is a global standard that was designed with high levels of cybersecurity protections from the very beginning. Advanced end-to-end encryption and provisions for authentication-ensuring subscriber identification module (SIM) cards are just two of the important cybersecurity features provided by LTE networks.
Commercial carriers are profit driven and thus focus on the enormous consumer markets. That translates into limited flexibility and responsiveness to the needs of industrial entities, even large, major investor-owned utilities. They are unable to make all of LTE’s flexibility and advantages available to industrial entities within a guaranteed service level agreement (SLA). Coverage and capacity are designed around population and do not necessarily cover utilities’ critical areas. They have to put their consumer customer base first. Can an electric-power utility be assured that its critical control functions will not be impaired when millions of wireless subscribers are streaming the Super Bowl?
Private ownership of a custom-built LTE network is the answer because it provides the winning combination of highly suitable technology with total network control.
The advantages of a privately owned LTE network are numerous:
- Coverage—The king of any wireless system’s requirements. With private ownership, the number and location of sites can be designed up front to meet the requirements of the organization; they also can be adjusted as needs change—for example, if a new power plant is constructed or an old plant is shut down.
- Capacity—When device density does not coincide with the general population, or changes due to specific activities, additional sites can be provided on a permanent or temporary basis as needed to support the required data volumes.
- Configuration and customization—In the consumer world, voice communications may have priority over other types of traffic, primarily data; in a network owned and operated by an electric-power utility, data communications likely will require preferential treatment—for example, the need to disconnect faulty circuits likely will take priority over any other traffic.
- Upgrades and maintenance—The ability to plan upgrades or maintenance so that they do not interfere with the utility’s primary mission, as opposed to depending on a commercial carrier’s schedule, is a key item for any mission-critical operation.
- Expansion—Electric-power utilities exist in a dynamic environment—mergers and acquisitions are common and such events may require network expansion. Experience has shown that incompatibilities concerning the respective communications networks can delay or diminish post-acquisition/merger integration of the involved utilities.
- Access to multiple spectra (licensed, unlicensed or shared)—The ability to mix and match spectrum can be advantageous, because doing so may provide technical and financial advantages. For example, not all applications are equally sensitive, and devices that operate in unlicensed spectrum may be significantly less expensive than equipment operating in the licensed airwaves. Also, different frequency ranges are characterized by different coverage performance; hence, mixing and matching them is another important design-optimization tool.
- Security—In addition to the cybersecurity features inherent to LTE, private ownership of a network provides an opportunity for total isolation from public networks, if so desired.
- Reliability and resilience—Both are crucial and often are cited as the commercial wireless networks’ Achilles heel; commercial carriers design high level of coverage overlap in high-density population areas and are just not that concerned about losing a site for a while and are reluctant to invest in physical security, backup power, redundant backhaul and other measures required by electric-power utilities; with a privately owned network, utilities are in total control of the reliability aspects of network design
- Fixed cost/revenue potential: Last, but not least, private ownership provides not only a potentially higher level of cost control over the costs, but also, under some circumstances, provides income opportunities borne of sharing excess resources with other entities
Electric-power utilities have numerous and myriad challenges, opportunities and day-to-day challenges that require robust, reliable and cost-effective broadband communications. While Long-Term Evolution (LTE) networks on a high level will meet this need, the standard services offered by commercial wireless carriers will not. Consequently, electric-power utilities seriously should consider deploying a private LTE network to realize all of the advantages identified in this article.