Primer: Edge computing in hostile environments
There really is a Nothing, Arizona. It's located approximately 100 miles northwest of Phoenix, and as the name suggests, it lacks many of the amenities that most businesses consider essential, including reliable broadband connectivity.
There are many Nothings in the U.S. and elsewhere. Yet a number of these places either have or will soon have Industrial Internet of Things (IIoT) devices, ranging from agricultural sensors to oil well monitors to environmental observation instruments. Providing such IIoT deployments with reliable connectivity and sufficient bandwidth can be both challenging and expensive.
Although 4G/LTE's reach continues expanding, there are places it may never reach, such as deserts and the sea. "There are two options when there isn't infrastructure in place," says Russ Rivin, IIoT senior analyst at Lux Research, an independent research and advisory firm. "You either put in your own infrastructure or use the one infrastructure that’s pretty much everywhere: satellite."
There are pros and cons to using different types of IIoT communications media, notes Michael Tennefoss, vice president of strategic partnerships at Aruba, a Hewlett Packard Enterprise company. "Satellite communications can reach virtually every terrestrial area but has high transmission costs and low throughput rates," he says. Cellular connections, on the other hand, are available throughout most habitable areas but not in the most desolate locations. "Fiber optics deliver high throughput and can be used in on-shore, off-shore, and sub-sea applications, but it is expensive to deploy," says Tennefoss.
Microwave links provide yet another connectivity option. "If you’re close to a place that has a broadband infrastructure, you can put in a network that links to a base station that then connects into the remote infrastructure," Rivin says. "Generally, you would want to use a wired network, but the connection can also be done through microwave communications, just like cell phone towers do, leading to an area that is supported by a commercial, mobile network operator." The drawback to microwave is that links are generally limited to line of sight, and microwave towers are expensive to install and maintain.
Broadband connectivity in the IIoT
Pat Smoker, head of Purdue University's College of Agriculture IT, understands how difficult it can be to maintain long-distance connectivity in locations where suitable broadband communication options are limited. Smoker is currently supervising a major network upgrade project at Purdue’s Agronomy Center for Research and Education (ACRE), a 1,408-acre field site dedicated to crop and soil research. Located in north-central Indiana, the farm sits in a rural enclave seven miles northwest of the main Purdue campus. More than 100 students and researchers use ACRE's facilities to research various projects.
The project's initial phase connected ACRE to the main campus with an aggregated 20 GB fiber link. The deployment replaced a distributed 802.11G wireless network that connected primary buildings at ACRE back to the campus with a single 54 MB microwave point-to-point connection.
The project's second phase ran fiber to an existing weather tower on which an Aruba access point (AP) was mounted to provide connectivity to devices within a 2-kilometer circle around the tower. The AP also supplies a point-to-point connection to a remote mobile trailer for research evaluating greenhouse gas emissions. "We were then able to test signal strength throughout all phases of the growing season, as well as mobile hot-spot connectivity," says Smoker.
A third and final phase will provide a field-scale IoT infrastructure across approximately 1,400 acres of research plots at the farm. Both permanent and mobile towers will be installed to accommodate various farm operations and provide signal strength where needed.
Smoker says the investment was necessary to help ACRE keep pace with the needs of current and future research projects. "Limited broadband infrastructure significantly impacts the efficiency of data collection, which in turn limits the time for discovery," he notes.
The 2.4 and 5.0 GHz bands used in many modern IoT networks offer the advantage of high throughput rates approaching 1 GB per second. The trade-off is relatively high-power consumption rates and the limited distance a signal can be transmitted and received. Use of lower bands, such as 900 MHz, requires much less power to transmit and has a significantly lower path loss. "This enables much greater distance using less power," Smoker says. "However, the amount of data transmitted per second limits the use of 900 MHz technology to applications in which only small streams of data need to be moved."
Each has, or will have, respective trade-offs. "Current plans do not call for switching to another connectivity technology, but we are certainly considering an integration of 2.4/5.0 GHz, 900 MHz, and 5G cellular technologies," he adds. "How to seamlessly blend the mix for research and teaching will be the goal."
Edge computing costs have fallen faster
While Purdue and many other organizations are biting the bullet and investing in the resources necessary to bring reliable broadband connectivity to remote sites, others are waking up to the idea that many, perhaps even most, IIoT deployments don't actually need first-class communication capabilities. For these IIoT adopters, edge computing provides an acceptable, cost-effective alternative to full-time satellite, fiber, and microwave connections.
As its name indicates, edge computing pushes most of the data processing out to the edge of the network, close to—or even at—the IIoT device, minimizing the quantity and frequency of data that needs to be moved off site. "The approach keeps data rates low, enabling expensive connectivity resources, such as satellite links, to be used more efficiently and cost effectively," Rivin says.
"The slower the speed of the wide-area network and/or the higher its cost, the greater the incentive to locally process and aggregate IoT data prior to transmission," adds Aruba's Tennefoss. "The cost of edge processing has fallen much faster than the cost of wide-area communications, making edge processing increasingly more affordable."
Edge computing is suitable for an array of IIoT applications, ranging from measuring flow rates to temperature monitoring to assessing motor performance. "You don’t need, for instance, to get a temperature reading every minute," Rivin says. "It doesn’t usually change that fast, and in any case, if it goes up and down by half a degree, it's probably not an issue."
Many edge computing systems also possess the intelligence to automatically activate a protective or corrective measure in the event an anomaly is detected—such as automatically slowing down or shutting off an overheating pump. "It you think about it, if something goes wrong in a desolate area, notifying someone 800 miles away that a critical event is occurring is mostly just frustrating," Rivin says. "Even if the measure invoked is only a Band-Aid, it can at least keep a lid on things until human assistance arrives on site."
Infrastructure takes years of planning
Any organization planning to deploy IIoT devices in an infrastructure-deprived location needs to carefully evaluate its current and future needs as well as the available connectivity options. "What information do you want, and what do you want to use it for?" Rivin asks. "How will you optimize information in relation to the cost of data transmission and the bandwidth available?" Edge computing may help trim the expense of transporting some types of IIoT device data. More time-sensitive data may have to be relayed via fiber, microwave, or satellite links at a higher cost.
Start planning as soon as possible, Smoker advises. "The most time-consuming and costly portion [is] construction—installation of towers, electricity, etc.," he observes. "Some of these elements take multiple years, and need to be planned and scheduled well in advance of when the technology will be applied."
Deep analysis may even lead some organizations to the realization that IIoT technology isn't necessary or appropriate for a particular desolate IIoT installation. Evoking memories of the now largely forgotten office "sneakernet," Rivin notes that device data that's not particularly time-sensitive can be physically transported to a convenient connected location for uploading to enterprise servers or the cloud. "This might be the case for data captured on an oil rig, for example," Rivin says. "There will be people who travel to and from the rig on a fairly regular basis, so one of their tasks might be to swap out a hard drive or tape backups and bring the data back to headquarters or a field office."
IIoT and network technologies are evolving rapidly, he adds, so organizations with deployments in desolate locations should make it a point to revisit their connectivity strategy every few months to see if new and potentially less costly communication options have become available. "I know, for instance, that satellite companies are looking to the whole IoT as one of their growth opportunities, so they’ll be adding features and changing their payment plans," Rivin says.
Even for organizations toiling away in places like Nothing, Arizona.
Internet of Things in remote places: Lessons for leaders
- Evaluate current and future needs and connectivity options when planning to deploy IIoT devices in infrastructure-deprived locations.
- Plan early. Construction and installation of infrastructure like towers, electricity, etc., takes years of planning before technology is applied.
- Edge computing can provide a cost-effective alternative to full-time satellite, fiber, and microwave connections.
- Revisit connectivity strategies every few months. Less costly communication options might have become available.