Why 802.11ac Will Kill The 5 GHz Wi-Fi Band

[stevech]

To offset the small increased attenuation at 5.8GHz, the vendors can just increase the transmitter power and/or antenna gain, and nill the difference.
If the market will bear that cost.

 

[sfx2000]

To offset the small increased attenuation at 5.8GHz, the vendors can just increase the transmitter power and/or antenna gain, and nill the difference.
If the market will bear that cost.

EIRP is very limited in most 5GHz blocks - so the max is set for the most part - I'm not a big fan of the very wide channels that 802.11ac provides, but for the most part, I think this is a non-issue for many folks.

It'll be more of a challenge in the enterprise space - and there I think it'll likely be a while before ac is deployed there, except in limited contexts - a few vendors sites that I've been at - some of them are starting to deploy HT40 in the 5GHz bands now - so this says that 2-3 years from now, we'll start to see 802.11ac maybe in the enterprise space.

More of a concern would be in the apartment/townhome high density home space - there it can be a concern, not just for competing AP's that you can see, but the noise floor in general will be up a bit.

FWIW - my neighbour has a Linksys E4200v1 - and he is running in dual band mode w/5Ghz enabled - I'm sitting about 50 feet from his AP now - I can see his 2.4GHz SSID, but his 5Ghz (it's enabled, I helped set him up), I cannot see it from my office... we're in single family homes - if he was on the other side of the wall in an apartment, it would be different.

 

[dduttonnc]

I do NOT think AC will kill the 5GHz band LOL

I think the author was a bit dramatic.

Here's why. Take your iphone (or whatever), and walk 50ft away from your house.. guess what? NO SIGNAL. 5Ghz doesn't penetrate walls well

Heck, I had to buy TWO routers because my Asus router upstairs couldn't get downstairs! I hired a cabling company to run a Cat 7 drop from my office upstairs to my entertainment system downstairs. That way my PS4 and xbox 360 are now WIRED, and I now get 5Ghz at 80-100% anywhere in my house.

If I walk more than 25-50 ft from my house, I LOSE it.

Now if I use my laptop, then it goes about 100ft MAX b/c the laptop is MUCH stronger than a phone or tablet... but even after 25-50ft, the signal is WAY down at -75 to -80db.. so even if it made it at that level into someone's house, their router would be broadcasting at -30 to -50db and my wifi wouldn't even be a blip b/c the noise would be so low...

So let someone with AC use every, single, channel, it it were possible. It's not going to interfere with people

Granted in an APARTMENT complex, there could be some.. but go back to my house... I go downstairs, and I'm at -75, if I start using a device, my router ups its power a bit and I get -70 which BARELY works...

So IMO, ac will NOT kill the 5GHZ band LOL! 5Ghz simply cant go through solid objects well enough to cause neighbor to neighbor problems..

Plus many apartments and HOAs are now adopting Wifi policies!

I head the WIFI committee for my HOA.

Here are our rules
2.4Ghz= Ch 1,6,11 ONLY and ONLY 20MHZ, NO 40MHz allowed
5Ghz = Ch 36&40, 44&48, 149&153, 157 & 161 are the ONLY pairs allowed for 40Mhz operation. That way someone can use 165 if they really wanted to not be on the same channel. 80Mhz has similar groupings, and we BAN 160Mhz use (the banning of 160 wasn't my idea. I tried to convince people otherwise, but they felt NO one should be able to "hog" an entire band no matter if it interfered or not). Since many routers don't use beyond the 9 standard channels (they don't use the DFS ones). So we have no policy on that... but we will refine it as more AC networks start showing up.

My neighbor had TWO routers running on CH 1+5 and 7+11 in his house! Probably 1 on the 3rd floor and 1 on the ground floor, and the ch 6 overlap is minor.. but this guy was an IDIOT... he even used different SSIDs! LOL He got a 100$ fine and refused to change it. The hoa finally got a court ordered injunction ordering him to comply or face foreclosure on his house. So now his 2 routers use CH 1 on the 3rd floor and CH 11 on the ground floor with the same SSID.

Unless someone is in a RURAL area, they have NO business running 40Mhz on the 2.4Ghz band! This mucks things up even in the suburbs. My housing area has LARGE plots of land (0.5-2acres per house), and 2.4 still causes problems.

You use the SAME SSID and SAME channels, that way they SHARE the bandwidth... now granted @ 5Ghz, I use 2 routers and they use 2 different 40Mhz groups but same SSID, this way as I move about the house, my phone or tablets lock on and use the strongest AP and seamlessly switch between the 2.. but you can't do this in the 2.4 Ghz band, unless you use 20Mhz, then use 1,6,11 for multiple routers

We have no regulations on 802.11ad (60Ghz) (yet).

We don't police these rules, but if someone complains their wifi is slow, me or another tech savvy person, goes over with a laptop with Insider on it.. and if someone is violating the rules, we use an app to track their wifi, walk up to their house and write the address. They get a letting giving them 10 days to comply. If they fail to comply (or comply then go back to violation), it's a 100$ fine

And I live in NC.. NC is one of the few states in the USA where an HOA can foreclose your house if you 1) refuse to pay your fines, or 2) stay in violation thinking you can just pay the fine every month. I dont agree with this.. but it's my state law. So people don't cross their HOAs in NC

 

[stevech]

the notion, above, that 5GHz propagation losses and attenuation from construction materials will reduce interference... is not quite true. It's all about cost of products. In the US, max radiated power for omni antennas is far higher that products provide- due to costs. This can change with volume of products and/or with a new way to reduce HPA costs. Or user acceptance of larger antennas or switched-beam technology.

 

[dduttonnc]

Very true. But materials won't be as much a factor as stronger antennas. But most buy an antenna to hit their whole house

This still won't propagate far enough

No need fir large antenna in an apartment. 5Ghz should hit every room. It goes though horizontal wall just enough.

My point is , it's never going to interfere like 2.4. Plus in the USA , the FCC regulates what residential antennas can be. Go to strong and someone will turn you in

The FCC busted a guy 4 houses down last year for putting up a 2000ft range GRID wifi antenna. They are legal to buy but are for commercial use ONLY

If I see any of my neighbors over a certain db level, if file an FCC complaint. Boosters are good. Overboost is selfish and pointless.

 

[stevech]

Very true. But materials won't be as much a factor as stronger antennas. But most buy an antenna to hit their whole house

This still won't propagate far enough

No need fir large antenna in an apartment. 5Ghz should hit every room. It goes though horizontal wall just enough.

My point is , it's never going to interfere like 2.4. Plus in the USA , the FCC regulates what residential antennas can be. Go to strong and someone will turn you in

The FCC busted a guy 4 houses down last year for putting up a 2000ft range GRID wifi antenna. They are legal to buy but are for commercial use ONLY

If I see any of my neighbors over a certain db level, if file an FCC complaint. Boosters are good. Overboost is selfish and pointless.

grid parabolic? For unlicensed 2.4GHz, such an antenna can be legal - as the FCC part 15 regulations allow higher power as the antenna beamwidth narrows. Up to 4W as I recall, with very narrowbeam antennas, like 5 Deg on Horiz. There is no distinction of commercial/private in Part 15. In the US, the top few MHz of the 2.4GHz band can be licensed for high power under Part 90. It's rarely done.

There are tens of thousands of legal miles-long bridge links in 2.4GHz. Most are in 5.8GHz.

I'd be careful about predicting what will become of 5.8GHz unlicensed ... it could get crowded. But 2.4GHz is not a problem now. Lots of WiFi, but the vast majority of it is lightly used in terms of % utilization of available air time. No matter the density of WiFi APs/routers in urban areas.

Materials - do add up fast - wooden floors much worse than drywall. Concrete/masonry etc much worse than wood. There's an interesting NIST report on this. The difference between 2.4 and 5.8GHz in most materials is a few dB - not much compared to the free space path loss, often indoor at 80dB or more. Just 6dB difference in the two bands.

Today's MIMO WiFi doesn't lend itself to external antennas though.

 

[thiggins]

Thanks for your post. That is quite an HOA!

You will see multiple 4x4 AC routers announced at CES (if not before). So 160 MHz will be on us soon.

 

[remixedcat]

An HOA that regulates wifi? That's a good idea in a way but I would hate to have to deal with the other restrictions that could be involved!

 

[MaxGrit]

I head the WIFI committee for my HOA.

Here are our rules
2.4Ghz= Ch 1,6,11 ONLY and ONLY 20MHZ, NO 40MHz allowed
5Ghz = Ch 36&40, 44&48, 149&153, 157 & 161 are the ONLY pairs allowed for 40Mhz operation. That way someone can use 165 if they really wanted to not be on the same channel. 80Mhz has similar groupings, and we BAN 160Mhz use (the banning of 160 wasn't my idea. I tried to convince people otherwise, but they felt NO one should be able to "hog" an entire band no matter if it interfered or not). Since many routers don't use beyond the 9 standard channels (they don't use the DFS ones). So we have no policy on that... but we will refine it as more AC networks start showing up.

My neighbor had TWO routers running on CH 1+5 and 7+11 in his house! Probably 1 on the 3rd floor and 1 on the ground floor, and the ch 6 overlap is minor.. but this guy was an IDIOT... he even used different SSIDs! LOL He got a 100$ fine and refused to change it. The hoa finally got a court ordered injunction ordering him to comply or face foreclosure on his house. So now his 2 routers use CH 1 on the 3rd floor and CH 11 on the ground floor with the same SSID.

We don't police these rules, but if someone complains their wifi is slow, me or another tech savvy person, goes over with a laptop with Insider on it.. and if someone is violating the rules, we use an app to track their wifi, walk up to their house and write the address. They get a letting giving them 10 days to comply. If they fail to comply (or comply then go back to violation), it's a 100$ fine

And I live in NC.. NC is one of the few states in the USA where an HOA can foreclose your house if you 1) refuse to pay your fines, or 2) stay in violation thinking you can just pay the fine every month. I dont agree with this.. but it's my state law. So people don't cross their HOAs in NC

nice HOA win


HOA, like other forms of social power, can be used for good or evil