As I peruse the magical land known to my parents as the Interwebs, I often seek out subject material related to what I do for a living. I find it interesting that when you search for information on any sort of Industrial Wireless, you get hammered by lots of vendors advertising their snazzy new gear, or you get link after link of how to improve your warehouse WiFi. Better yet, you get inundated with articles claiming to “De-mystify Industrial WiFi”.
Well now, that sounds intriguing!
Let’s get De-mystified gang, follow me!
(I’ll spare you multiple articles I read and just summarize as best as I can)
First up in the De-mystification process is knowing your packet loss rate. Packet loss slows down communication due to high re-transmits. Additionally, packet loss can affect the reliability of various applications that run on the WLAN. While this is an excellent point, I hardly think that this exclusive to Industrial WiFi. Packet loss data is pretty important to any type of data network, wired or wireless. As a matter of fact, just about every network monitoring tool in the known universe can give packet loss stats in one form or another. Maybe the next example I found will be more exciting.
The second step in the De-mystification of Industrial wireless is identifying latency trouble spots throughout the WLAN. Latency is the delay in transmission of a message in a wireless connection… wait- this isn’t an issue just for Industrial wireless either! This too is an issue for any WLAN. How is knowing about latency issues any different from one WiFi network to the next?
Moving on, the third step is improving data throughput. To a degree, I would actually argue this point. Most Industrial WiFi that I have dealt with had relatively low data throughput requirements. From translated serial feeds for environmental controls, to the once every five-minute bursts of tank level gauges, throughput is generally minimal. Improving data rates to 802.11ax? I’m sorry, I mean WiFi6 levels would not really gain you anything here. It would be like putting an eight-lane superhighway through downtown Hayesville, North Carolina (population 338), it’s just not necessary. I believe we can hold off on the 80MHz channel bonding for the wastewater treatment center Scada sensors.
The fourth recommendation is knowing the interruption threshold. As in identifying the breaks in transmissions that happen when a client moves from one access point to another and keeping them as short as possible. Correct me if I am wrong, but I believe that is the very definition of 802.11 roaming. Knowing your roaming values and optimizing this process is important to any successful wireless network. It is well known that poor roaming leads to generally bad wireless network performance.
I am not feeling very De-mystified yet.
The fifth step down the path of de-mystification is figuring out the proper range for each wireless access point. Client density needs to be determined so that the correct cell size can be established. Once the cell size is established, it can be optimized by adjusting power levels and following a channel plan. I feel like I am quoting a textbook as I type this blog. Again, this is nothing specific to the industrial wireless paradigm, as it applies to all WiFi.
Well gang, I think we can just add “De-mystification” to the list of buzzwords that sales and marketing types jump on to help them with their hype. But, since we are on the subject, what are some of the more common real-world problems with WiFi in industrial and manufacturing facilities that I tend to come up against? From my experience, the list looks a bit like this: (in no specific order)
- Too few access points
- Poor channel planning / assignments
- Wrong AP or antenna type
- AP’s blasting out at maximum power
- Not disabling 802.11b transmission rates
- Co-channel interference
- Adjacent channel interference
- Non WiFi based interference
- The effect of stock and equipment within the facility
- Old firmware on clients
- Poor planning
- Lack of design validation and testing
Hmmm. Taking another look at this list, it can be seen that none of these items are exclusive to the manufacturing environment, either. The same problems and issues apply because it is the same systems being used in industry as are being used in carpeted spaces. The laws of physics that govern wireless transmissions are the same in a paper mill in Fernandina Beach, FL as they are in the headquarters building of JCPenney in Plano, TX.
Now I know what you may be thinking, “Dude, you spent a bunch of time in previous posts explaining how different industrial WiFi is from regular enterprise WiFi! What gives?” That’s true, I did. Perhaps I should explain a little farther then.
While the types of problems and issues in industrial wireless are the same as enterprise wireless networks, the frequency, causes, and severity of those problems are not. The rigors and means of mitigating those problems are also quite different when they arise in the industrial setting. A prime example of this is non-WiFi based interference. In your typical business office or educational building deployment, mechanical interference is rare. When it is found, it is usually some sort of HVAC or building control system and its influence is fairly compartmentalized to a few rooms or perhaps a hallway. In a manufacturing facility I have seen this kind of interference effect wreak wide-spread havoc, and leave you scratching your head about how to deal with it. In one case, there was nothing that could be done to mitigate interference as the source was a mission critical piece of equipment. All that could be done was to abandon 2.4 GHz altogether and migrate mobility services to the 5 GHz frequency. At another location, between mechanical interference and high reflectivity of surrounding equipment, neither 2.4 or 5 GHz could be used and a 900MHz solution had to be found.
What’s the moral of our story for this episode? You can’t demystify what you don’t really understand.
It’s true that it’s still Wi-Fi, but understanding the setting it’s deployed in is critical to truly being able to differentiate WLAN deployment and support between one environment and the next. Take “de-mystifying” with a grain of salt unless you’re reading the work of someone who has actually been there.
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