In this episode, we have a listener question from Steve Yuroff who asks:
When you have a business with neighbors (particularly residential apartments) where WiFi bleeds over, how do you do channel selection when the neighboring channel use can be an ever changing issue? Networks come and go, a new one could have popped up since I last surveyed.
Very good question Steve. This is definitely a challenge to work with when you have neighboring WiFi signals propagating into your environment.
The thing about WiFi is that it is an iterative process. You’ve probably heard this before because I’ve taken it from Keith Parsons and Andrew Von Nagy.
That means you gather requirements, plan, do your predictive surveys, deploy, validate, and optimize. That is a repeatable cycle. Channel planning is part of that process.
In the United States we have 3 non-overlapping channels in the 2.4 GHz spectrum and 25 non-overlapping channels in the 5 GHz spectrum.
When two or more access points are transmitting and receiving on the same channel it causes errors and retransmissions. It is the same as having the capacity of one access point because all devices, including the access points, are contending for air time.
WiFi is a half duplex medium in which one device can communicate at a time.
To answer Steve’s question, I use a combination of tools to select the best channels to avoid co-channel interference. The tools are listed below in the resources section.
Specifically in my experience, I am using Ekahau Site Survey to conduct pre-deployment or validation surveys to determine where access points are heard on a floor plan. I have also used spectrum analyzers such as Metageek’s Chanalyzer to gather more information such as channel utilization.
If you’re working with a limited budget, check out Metageek’s InSSIDer Office. Another option that isn’t ideal would be using Adrian Grenado’s WiFi Explorer but taking note of where signals are heard and on what channel, on a floor plan. The caveat here is that you are doing this on your device’s built-in WiFi card. Results could be different for another device.
Links and Resources Mentioned
- Keith Parsons on Episode 21
- Adrian Grenados on Episode 7
- WiFi Explorer
- Ekahau Site Survey
- Metageek Chanalyzer
- Metageek InSSIDer Office
- Fluke Airmagnet Spectrum XT
Thanks For Listening
I’m interested in how you plan channels around other WiFi networks that propagate into your environment? Let me know in the comments below!
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