RF Wavelength and 80211 Cell Sizing

While attending classes at the wonderful University of Akron (GO Zips!) WEP was still popular and I had to use a PCMCIA Card to run Cisco Leap to connect to campus Wi-Fi. It was at that time (mid 2000's) that I learned the hard and fast rule about maximum effective distance for wireless networks at the time. I think the year was 2006 and I was taking a class that mapped to the CompTia Network+ (I did not sit for the exam).

It was in this class that I learned of the inverse relationship between RF Frequency and RF Wavelength. Here it was demonstrated that the lower the frequency, the longer the wave, and the longer the wave, the better the penetration through objects. Another way to look at this is that shorter waves have a better chance of bouncing off objects than penetrating them (at least that's how I visualize it). Shorter waves also dissipate faster due to their nature.

Thus came the rule that you could achieve 300' in a 2.4GHz deployment and 180' in a 5GHz deployment. In another post, I will be performing testing of 2.4GHz and 5GHz (I don't have a 6GHz AP or client chips yet to test with) at various ranges to validate coverage and data rate. While thinking about this rule, I thought about the spectrum available in 2.4GHz and 5GHz, and noticed that there is quite a difference in the amount of available channels, quite a difference in the way that you can bond channels together (which increases noise by 3db, thus effectively decreasing cell size). So, this old rule is dated, at best when new technologies are introduced. Further complicating the issue Channel 36 has a longer wavelength than Channel 165.

Consulting page 216 in my CWNA-107 Study Guide I can see that Channel 36 operates at 5.180 GHz and Channel 165 operates at 5.825GHz.

Using the calculator found here at RF Cafe, I was able to determine the following:

Channel 36

Channel 165

Calculating the percentage of length difference here (0.168853/0.189879=8.892663e-7) is that the wavelength for Channel 165 is about 11% shorter than Channel 36.

My natural curiosity has given me a hypothesis to test here-

All things being equal, given the same data rate, environment, and equipment I should be able to expect 11% greater range on Channel 36 vs Channel 165 in a 20 MHz configuration.

This also raises another question for me-

Should my hypothesis for 5GHz spectrum prove to be true, what will the behavior be in the new 6GHz at both ends of it's spectrum allocation?

I look forward to posting more research and my findings on these topics as we learn these things together. I will be working on developing the test methods and I look forward to providing my findings.