Ultra Dense Wireless

[Nicholas_Tech]

Hello,

I have read through many already made topics but have not yet found a match for my scenario.

We are expanding into a new build that will have two bullpens worth of users. Each bullpen has 45 foot high ceilings and is otherwise open air. The rooms are 120x120 in size and will each have approximately 750 attached devices.

Adding more APs is not an issue from a cost standpoint, but as the AP density grows the problem of too many AP's in a small area also grows.

I am seeing a general consensus that each AP should handle about 60 devices without really starting to drop off, so the question is, how well will the latest generation of Meraki handle having 13-14 APs in a 120x120 space?

Thanks you for your time and consideration,

Nicholas

[JohnD]

A big challenge in open space is channel reuse tradeoffs especially with omnidirectional APs. Depending on whether you can use DFS 5 GHz channels and if 40MHz (as opposed to 20MHz) channel widths are a must have for your bandwidth requirements, you might have an issue with 5GHz. You will definitely have a 2.4GHz overcrowding issue unless you carefully disable 2.4GHz on most of the APs. 

In an ideal world, you probably want to consider using narrow/sectorized antennas for this sort of application. The MR42E/MR52E can be paired with narrow antennas that can help you avoid omnidirectional interference in a large open space.

[cmr]

Also please bear in mind that the 60 devices per AP comes from 30 devices per radio.  In a space like yours where 2.4GHz will likely need to be restricted to some APs, I'd go for 20 APs at minimum, you may need even more for a good experience.

However it may not be as bad as you think if the users vary in activity, at this density it starts to become more of an art than a science...

[NolanHerring]

I've linked it before, and its not Meraki, however if you ignore the fact that its a document from Aruba, and just look at the math, it basically applies to any vendor. This is a good read for your situation, but basically what @JohnD said, use directionals, channel-reuse is key, disable most if not all 2.4, try to leverage rx-sop, reign in your autoRF settings (power/channel) so they are not all over the place.

https://community.arubanetworks.com/aruba/attachments/aruba/Aruba-VRDs/54/4/Aruba_VHD_VRD_Engineerin...

[JohnD]

I would also add that if you end up going omnidirectional, or otherwise have more than a handful of APs, I strongly recommend manually coming up with your channel plan. The AutoTx component of AutoRF is fairly reliable if you set reasonable limits but I've observed that auto channel selection in a congested environment has the tendency to refuse to budge. It's simply not smart enough yet to not create auto channel plans that paint itself into a corner....

I do like Auto Tx though for resiliency. In case one of your APs goes down you almost certainly want the automatic power bump to neighboring APs to reduce the coverage hole. Most wireless problems crop up after you stop paying attention to the network and it's great when the cloud can do a bit of self healing. 

Oh and finally regarding RX-SOP: I have found RX-SOP to be nearly magical if you have no choice but to talk over neighboring APs that are not your own. However, if instead you are trying to get some of your own APs to talk over each other, aggressive RX-SOP settings can create more roaming problems because some clients get confused when an AP they hear loud and clear is pretending to be deaf to them. Use RX-SOP against your own APs as a last resort.