Though wireless network technology is primarily used by industry to bring connectivity to rotating equipment, to areas difficult to reach by cable or to widely dispersed or remote locations, it is increasingly finding use as a key network technology tool for the Industrial Internet of Things (IIoT). A prime example is how AW North Carolina, a Tier One supplier of transmissions to Toyota and Lexus, is applying the technology as part of its recent automation system upgrade.
IIoT applications commonly use several layers of networking technology, including SCADA in the plant, LANs (local area networks) in plants and offices, interlink or backhaul networks to connect the LANs and broadband, and broadband wireless. This broadband wireless network is considered by many to be the last step of connectivity in that it can be used to link sensors and controls in challenging environments, said Todd Rigby of Rajant Corp., a supplier of mobile, private, wireless network technology.
Rigby noted that many of the companies Rajant works with—which are largely mining, gas and oil, municipalities and water utilities—often consider LTE networks as their broadband wireless network of choice, without understanding LTE’s challenges in bandwidth/speed, flexibility, reliability and scalability. Each of these characteristics are “all virtues of a truly IIoT-ready network,” he said.
For example, Rigby pointed out that, when it comes to bandwidth/speed in LTE, different nodes perform different functions. "Infrastructure nodes act as access points, while mobile nodes can only pass data to infrastructure nodes," he said. "Also, though LTE towers are tall, there are fewer of them spread across an area, which creates coverage challenges for these networks.”
There is also the issue of configuration with LTE. “A cell site has a fixed number of connections it can support, making it easy to overload the connection capacity of infrastructure,” Rigby said. “A network, like LTE, which relies on infrastructure nodes, creates points of failure. If an infrastructure node goes down, its mobile clients cannot access the network. Additionally, infrastructure and mobile nodes can only access their respective dedicated frequency, and loss of line of sight can create connectivity challenges. There is no real way around signal blockage or interference.”
All of this creates issues for manufacturers hoping to use an LTE network as the broadband layer of their IIoT, said Rigby. “The number of connected ‘things’ in the industrial operating environment will continue to grow, and IIoT applications like machine to machine (M2M) connectivity will involve a huge number of devices that generate sporadic transmissions of short packets. LTE will struggle under the weight of the signaling traffic M2M will generate.”
To address this, Rajant offers a technology known as kinetic mesh. According to Rigby, kinetic mesh has the bandwidth/speed to handle IIoT because all nodes are equal in its configuration and can be interchangeably fixed or mobile. “If a device can see another, it can talk to it, communicating on a peer-to-peer basis,” he said. “If the devices cannot ‘see’ each other, intermediary equipment can be introduced as devices get farther away from each other, making the network efficiently scalable. Kinetic mesh is full duplex, meaning data can be received by a node on one frequency and sent simultaneously in another frequency, which creates unwavering high speed and resulting in extremely low latency. The network uses all available frequencies and paths for all network functions, allowing it to deliver data with ultra-low latency to support real-time, bandwidth-intensive, next-gen IIoT applications.”
I asked Rigby how kinetic mesh differs from frequency hopping, the well-known wireless technology behind Bluetooth, GPS and other communications technologies. Rigby explained that frequency hopping is a wireless technology that spreads signals over rapidly changing frequencies. Each available frequency band is divided into sub-frequencies. Signals rapidly change, or ‘hop’ among these sub-frequency bands in a pre-determined order. A kinetic mesh network dynamically selects the fastest path from hundreds of potential options to automatically route around interference, signal blockage, etc., without losing a beat. This mitigates the effects of given radio interference on the network. Nodes make multiple simultaneous connections, so no connections must be broken for new ones to be made. There is no handoff of the signal, just simply consistent, reliable connectivity via a variety of traffic paths and frequencies.
As a side note: if you’re interested in some frequency hopping trivia, there is a great documentary on Netflix about Hedy Lamarr, called “Bombshell: The Hedy Lamarr Story,” which provides the back story on how she helped develop the idea behind frequency hopping during World War II. Now, back to kinetic mesh…
Flexibility is inherent in kinetic mesh networks because each node can maintain multiple simultaneous connections. None has to break for new ones to be made. “Peer-to-peer networking software runs on every node to dynamically direct traffic via the fastest available path at the given moment," said Rigby. "The network self-optimizes as nodes move and conditions change, reacting immediately to changes in network topology, network load and external environmental conditions to keep operators constantly connected to, and in control of high-value assets on the move. If a path is blocked or interference is identified, instead of dropping connections, information is instantly redirected over the best available path(s), creating total mobility and communications agility. Also, multi-transceiver redundancy eliminates any single point of failure.”
This flexibility also relates to the scalability provided by kinetic mesh. “Nodes can be rapidly deployed virtually anywhere, on virtually any asset, to extend or enhance operational coverage,” Rigby said. “Any expansion does not cripple connectivity; rather, kinetic mesh strengthens as it grows. Each additional node establishes new pathways for data to use, making the network more resilient as it expands, without compromising speed or performance.”
Getting more specific to industrial network particulars, Rigby points out that Rajant’s kinetic mesh technology is a Layer 2 network, meaning that it can transport an IP/UDP data stream, including voice and video. “For customers who have legacy SCADA data, we recommend a serial/IP converter,” he says. “Basically, you connect your SCADA devices to the converter and plug the Ethernet cable from the converter into any Rajant BreadCrumb [a wireless network node].In this way, customers do not need to ‘rip and replace’ their legacy equipment.”
Though largely installed in the mining and oil and gas industries, Rigby says Rajant is interested in other industries such as aerospace, automotive and batch processing because the company’s InstaMesh routing software can be integrated into other form factors, radios and devices that support a wide range of autonomous functions and applications that are driving productivity in these industries. To date, other wireless technologies have had more success in the indoor enterprise environments, but many of these verticals require mission critical networks and not traditional Wi-Fi, thereby providing an opening for consideration of kinetic mesh.