Wave 1 vs. Wave 2 - High Density

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How many more clients could an 802.11ac Wave 1 AP take on vs. a Wave 2 AP? capable AP -- with all other things being equal.  

The area I'm looking  would be an outdoor amphi area, the clients are all mobile devices with almost 60% being 802.11ac capable.  It looks like almost 10% are Wave 2 compatible at this point (with most being iPhone 6s which apparently have early-stage wave 2 radios).  Of course this mix 'improves' gradually.  Usage is light: browsing, email and messaging and some social media with maybe 3/4 of client devices simply auto-connecting while it's in their pocket.

Could I expect, a marginal improvement in the number of connected clients it can handle (maybe 10%) or a significant improvement (say, 50% ?).  

Right now, we can handle about 85 users per AP1130 (including both 2.4 & 5Ghz radios) in this scenario.

I'm curious what others are seeing - or expecting.
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Paul Ainslie

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Posted 1 year ago

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Jonathan Hurtt

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Well 802.11ac Wave 1 and Wave 2 are very similar except these three things.

1. Wider Channel Width
2. 4th Spatial Stream

In your scenario I would say you would not see much of an impact from Wave 1 to Wave 2. 

With Wave 2, 160 MHz wide channels are introduced but in most environments two things will prevent this from being a benefit. 

1. There is not enough spectrum,  there are only 2 non-overlapping 160 MHz wide channels today so you could only deploy 2 APs before you run into Co-Channel Interference. 
2. Client support for 160 MHz Wide channels is not wide spread, so even if your AP was configured 160 MHz, the client doesn't support it. 

MU-MIMO is probably the biggest feature of 802.11ac Wave 2, but there are very few clients that support MU-MIMO (and the iPhone 6s is not one of them). Also to take advantage of MU-MIMO all clients that the AP is transmitting to must be MU-MIMO capable so one client could prevent the use of MU-MIMO (read more here: https://community.aerohive.com/aerohive/topics/does_mu_mimo_aps_will_require_new_client_mu_mimo_awar...

Also the 4th Spatial Stream would only be beneficial if the client supports a 4SS, which most don't or if MU-MIMO is being used which earlier I explained the potential of that happening. 

With all that said, the only benefit from Wave 2 would be newer hardware than Wave 1. Also newer features like Software Definable Radios which allow for Dual 5Ghz use rather than Traditional 2.4 +  5Ghz radio configuration. 

Hope that helps.
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Marcel Heß

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Good answer, thank's for that.

Clarifies the situation for me!
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Alan Stephen Davies

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The problem with large numbers of clients is not the maths...but the size of the collision domain.  If you have an AP delivering say 200MB/s to a single client...you might just get 10 clients with 20Mb/s each.  So far so good.  But by the time you get to 20 clients - which you might expect to get 10Mb/s each...you find they only get 5Mb/s each (probably won't be quite that bad, but it won't be good either).  And it gets worse.  50 clients will struggle to get 1Mb/s each....maybe not even that much. Yes APs can support possibly several hundred clients connecting...but they are not going to deliver meaningful data rates to those clients.  Rather than using a single 160MHz wide channel - which would deliver lightening speeds to a single client - you are better off with 4 access points on separate 40 MHz channels - or possibly 8 APs on 20 MHz channels if you are serious about delivering useful bandwidth to large numbers of clients.  (Of course...a single client on its own using that system will get a rather limted speed).
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Crowdie, Champ

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For high user count outdoor deployments I have had success with the following:
  • Use directional antennas to contain the signal.  Do not use omni-directional antennas.
  • Use 20 MHz wide channels.
  • Use low transmit powers.
  • Have a single mandatory (basic) data rate - either 6, 12 or 24 Mbps.
  • Disable load balancing.
  • Disable MU-MIMO (if applicable).
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Paul Ainslie

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How many users can an AP handle if it's configured as you just mentioned?

Our use case is an outdoor Amphitheatre.