Wi-Fi and the Future of Wireless Sensor Networks
Most of the discussion around wireless networks centers on WirelessHART and ISA 100. Why isn’t Wi-Fi considered?
While developing the November 2012 feature article for Automation World on wireless sensor networking trends, I couldn't help but notice that Wi-Fi rarely, if ever, got mentioned. Cellular networks were referenced in a few instances, but not Wi-Fi.
Of course, office grade Wi-Fi equipment isn't up to snuff for industrial applications, but what about the communication protocol itself? After all, it’s clearly capable of handling massive amount of global communications.
It turns out that there are a number of people in industry who do think Wi-Fi is a viable network for industrial use.
One of those people is Mike Fahrion, director of product management at B&B Electronics, a manufacturer of rugged wired and wireless communications products including Ethernet servers and gateways, and cellular routers.
Fahrion contends that Wi-Fi is viable for a number of reasons, including:
• Interoperability. Compatibility with Wi-Fi and Wi-Fi-enabled devices is no longer something you have to think about. But when you deploy an 802.15.4-based equipment, such as Zigbee, WirelessHART or ISA100, you do.
• Though 802.15.4 has its roots in low cost end-nodes, and is a lighter stack than a networking model like 802.11, you need additional equipment. For example, to deploy Zigbee, you also need a ZigBee coordinator and a Zigbee router. So if you're looking to deploy a large wireless sensor network, the cost can rise exponentially.
• 802.15.4 represents about a 2 percent unit market share of wireless nodes. The remainder is comprised of cellular, Bluetooth and Wi-Fi. The fact is, the R&D dollars behind Wi-Fi are driving the technology forward much faster than 802.15.4
• Since the introduction of 802.15.4, the size, cost and power requirements of Wi-Fi (802.11) have decreased on a dramatic curve in comparison to 802.15.4.
• Fahrion also suggests that we consider Moore’s Law. “If you put your forward-thinking cap on, along with a quick refresher of Moore’s law, you start to favor an architecture that pushes intelligence out to the end node and eliminates specialized infrastructure,” he says. “Yes it raises the price and power requirements of the end node, but Moore’s law and market forces (such as Broadcom’s 802.11-related investment of nearly $2 billion in 2011 alone) seem to be joining forces to make that problem effectively a non-issue.”
My discussions with Mike on this topic will be explored more in-depth in an Automation World Deep Dive video to be released soon. So stay tuned to this blog and automationworld.com for more info on this coming soon.
In the meantime, feel free to weigh in with your thoughts on this topic in the comments section below.
David Greenfield has been covering industrial technologies, ranging from software and hardware to embedded systems, for more than 20 years. His principal areas of coverage for Automation World focus on technologies deployed for factory and process automation. Contact David at [email protected] or follow him on twitter @DJGreenfield.
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