Key highlights
- The article highlights how modern wireless technologies are evolving to support the need for more data, lower latency, and increased device connectivity on the plant floor.
- It provides a clear comparison between Wi-Fi and private cellular networks, helping process engineers choose the right technology based on performance requirements, cost considerations and scalability.
Because users always want more data, reduced latency and added wireless devices, wireless networks like Wi-Fi and cellular are growing to accommodate them.
“4G cellular is progressing to 5G and private cellular, which uses dedicated infrastructure for individual sites. Private cellular is like the cellular equivalent of Wi-Fi because it’s arranged similarly with miniature towers, switches, specialized servers and Ethernet cabling all serving client devices,” says Danny Walters, product marketing specialist for wireless and surveillance at Phoenix Contact. “Meanwhile, Wi-Fi 6 and its usual access points and client devices are upgrading to employ Wi-Fi 6E and Wi-Fi 7.”
Walters reports the primary decision for plant-floor users is deciding whether to use Wi-Fi or private cellular by determining their required performance levels and how much they’re willing to invest. As more devices and users join a wireless network, more Wi-Fi access points are needed. Eventually, so many Wi-Fi access points are added that private cellular may be worth considering.
“Every user has to decide how good is good enough for their operations and facility, as well as what’s cost-effective for them,” explains Walters, who estimates that 750,000 square feet of private cellular coverage could cost as much as $100,000 a year. Both large and smaller/local carriers are available, and some can implement a hybrid cellular network with both public and private elements.
Study and survey
Walters adds that Phoenix Contact offers several services to help users determine which wireless network and support components will be the most useful for their operations and environment. They begin with a study path to educate potential users about wireless options. This is done by performing site assessments using analysis software and GPS coordinates to determine suitable radios, radio placement and antennas. This is followed by onsite visits by Phoenix Contact’s Engineering Services Group to gauge radio frequency (RF) interference and latency issues, test available devices for speed and performance, and even perform device configuration as needed.
“Education about wireless is important because technologies like 5G are often misunderstood due to advertising fluff that promise the moon but doesn’t deliver,” says Walters. “These cellular standards are released in 10-year roadmaps by the Third Generation Partnership Project (www.3gpp.org) that unites seven telecommunications, standards-development organizations. While we’re presently on the fifth-generation cellular standard, another sub-section or part of the standard gets ratified each year. Marketers often tell users about parts of the 5G standard that haven’t been ratified yet, and may not be available for another couple years in 3GPP’s timeline for that overall roadmap.”
Get your subscription to Control's tri-weekly newsletter.
Unclogging Wi-Fi congestion
Walters adds that Wi-Fi 6, 6E and 7 are ushering in a new phase for Wi-Fi because they’re making the protocol more efficient, rather than just adding more powerful devices with greater data processing horsepower, which is what they did before.
“Wi-Fi’s developers took a step back, and made it able to scale larger-volume communications by adding an OFDMA feature, which lets Wi-Fi subdivide its usual 20-MHz channel into multiple subchannels,” explains Walters. “In the past, Wi-Fi access points gave client devices the entire 20 MHz channel even if they didn’t need it, so portions of the channel just went unused. This meant communications to multiple client devices had to run sequentially, which required more spectrum and bandwidth. Now, Wi-Fi 6 with OFDMA lets access points send individual subdivided messages at its usual 2.4 GHz and 5 GHz frequencies, but they can be relayed to multiple client devices at the same time, making much more efficient use of the 20-MHz channel.” Orthogonal Frequency-Division Multiple Access (ODFMA) is a wireless networking technology that divides a channel into subchannels, allowing multiple devices to transmit data simultaneously.
“While Wi-Fi maintains its usual 2.4 GHz and 5 GHz operating frequencies, 6E takes the efficiencies that Wi-Fi 6 gained, and runs them at 6 GHz. “This is a much wider highway with a lot more lanes,” adds Walters. “Next, Wi-Fi 7 will let Wi-Fi devices communicate on all three frequency bands to achieve greater redundancy, higher data rates, or lower latency.”
