In your blogpost, you say the FCC is adding 195 MHz of spectrum for Wi-Fi. For us non-spectrum-geeks, is that a lot?
The FCC is saying that it's 35% more spectrum. That sounds like a nice number. What I then did was made some educated guesses about the number of 20-MHz channels this would add to the 5-GHz band. And if you look at the channels, it's actually 60% more spectrum.
How do you figure?
The "existing" 5 GHz channels - before the new FCC announcement -- were these: 22 20-MHz-wide channels in three bands.
[Gast's technical breakdown is as follows:
5.17 - 5.33 MHz: 36, 40, 44, 48, 52, 56, 60, 64
5.49 - 5.725 MHz (these are the Dynamic Frequency Selection channels, which Wi-Fi radios must avoid if they're used by weather or other radars): 100, 104, 108, 112, 116, 132, 136, 140, 144
5.735 - 5.835 MHz: 149, 153, 157, 161, 165]
In that second band, FCC removed three channels between 116 and 123 - 120, 124 and 128. This gap was for [protecting] a new wind shear radar [in effect, a special kind of weather radar] being developed by the Federal Aviation Administration for airports. The FCC concluded that outdoor Wi-Fi was interfering with this radar. That decision blew a hole in the middle of the available spectrum in this band.
The newest FCC announcement adds back the 3 channels in the DFS. It also adds new spectrum, so you have two [entirely] new bands. My best guess is that this new spectrum is good for 10 totally new channels. My guess at channel numbering is:
5.350-5.470 MHz: 72, 76, 80, 84, 88, 92
5.850-5.925 MHz: 170, 174, 178, 182
So, pre-announcement you had 22. Post announcement, you have 22+3+10=35, an increase of 62%. It's a much bigger improvement than just the [added] spectrum, and that's way more important to me as Wi-Fi engineer.
Why is that important?
First of all, we now have 60% more channels for high capacity networks. I once did a Wi-Fi network for a tradeshow, when everyone had 11b and 11g devices on the 2.4-GHz band, in a football-field sized exhibition hall, with in effect just three channels. With Wi-Fi today, if any one person is transmitting on a channel, no one else can "say" anything. [So] it's basically impossible to lay out any kind of high capacity network with just three channels. That's why the 5-GHz band is so important.