Wireless Access

We are designing wireless as a part of our auditorium renovations.  I've been reading the Aruba white paper on designing for high client density areas:

http://www.arubanetworks.com/wp-content/uploads/DG_HighDensity_VRD.pdf

Based on this, I'm looking at floor mounting 7 attennas staggered throughout the room underneath seats to handle the bulk of the clients.  The attennas would connect down to AP214's mounted above the ceiling on the floor below.  I'm thinking that ANT-16 is the most appropriate antenna for the job, but I'm not sure.  I would also mount 2 AP215's to cover the whole room for devices in the balconies and other devices that may not reach the floor APs.

Does anyone have hands on expierence with this type of design?  Do you all have any guess to active client densisties that we would be able to support?

Also, a side-bar question.  Other than the additional uplink port, is there actually any reason to go up to the AP220 series over the AP210 series?  As is, I don't see any reason to go up to that series.

Thanks!

MooreALX,

Can you share the dimensions or a generic floorplan of the area you would like to cover?

Mounting on the ceiling is the preferred method here with built-in or omnidirectional antennas.  Mounting under the floor could probably be the most expensive and  is usually reserved for stadiums.  Mounting on the floor with external antennas could require a box for protection and could require more testing to ensure you get the coverage pattern that you need with possible objects being over the in-floor antennas....

Please see the AP matrix here:  http://www.arubanetworks.com/pdf/products/MAT_AP.pdf to see a side-by-side comparison of the AP224/225 series vs. the 204/205.

The attached heatmap is showing the design that we are looking at.  The two APs that I circled in blue are flanking the stage, and would be the two AP215s positioned to cover the entire room with signal.  The rest would be the 214's that we've been discussing.  The auditorium is roughly 120' x 85'.

The other possibility that we've thought about to avoid damage to the antennas would be to go to ANT-18' and mount them at the heigth of the suspended ceiling on the floor below pointing up in the same pattern that we are looking at for the other design that I mentioned.  This is actually one of our older buildings on campus, and has a wood decking floor that would be easy to get signal through.

I understand the differences between the 204/205's and the higher series.  Other than the second uplink, I don't see the difference between the 214/215's and the 224/225's.

MooreALX,

What is the capacity of the auditorium?

What is the mounting heights of the access points if you put them on the ceiling?

The room holds roughly 1600 people.  We are currently covering the room with 2 AP115's.  One is located in the auditorium, the other is on the floor below centered under the main group of people.  We typically see 100-150 connected clients per AP when the room is filled to capacity.  We don't have any plans to have a senereo where we would have the room filled to capacity and have everyone connected.  However, we would like to gain the ability to have several hundred people all connected during a smaller gathering for an online test or online survey.

Everything I'm reading states that the 214/215 is capible of 3 spatial streams, only the 204/205 is 2 stream.

I've heard these claims of "horsepower".  With no official specs showing any differences and no studies that I'm aware of showing any real world differences, I'm not inclined to spend the extra money to go with the 220 series over the 210, and it would be an uphill battle to get leadership to buy in.

MooreALX,

The big question is what is your goal, right?  For now you have two access points there.  Do you have complaints that you want to address?  If you do not have many complaints or there is not the expectation that many, many users would be able to use the wireless simultaneously, it is quite possible that you do not need AP225s.  If you were asked to create an environment where you had the guarantee that the majority of your users in the space would be able use the internet at the same time, you should consider AP225s for their higher performance.

With that being said, you should have no more than 9 access points in the space, because there are no more than 9 non-overlapping channels in the 5ghz band at 20mhz.  In such a small space, any user could easily see any access point you deploy, so after a certain number of access points are deployed, adding more just creates contention.  User devices also broadcast RF and they also contend with access points and other users to gain access to the medium.  Since you have two access points in the space, you might want to deploy two or three more, spaced out and see how many users attach to those to understand your  true traffic patterns and to gauge the expectations of your users.

Thanks for the good responce, cjoseph!  My underdanding of the document that I was referencing was that the advantage of floor mounted APs was the the people themselves in the auditorium would help limit the range of the APs reduncing the contention issues.  Is our auditorium too small to go to some of these designs?

The big thing that is being asked for is classes of 200-300 people (or more if possible) could all take online tests or online surveys at once.  We have a lot of expienience showing AP105s can usually handle 30 clients in this type of enviroment.  We don't have much expirince with the AP115s yet, but we seem to being doing 50 in the same enviroment fine.

Floor-mounted APs have increased cost and complexity because you would have to (1) run the cable through the floor (2) select  enclosures to protect your access points and (3) make sure the seats do not have metal in them that would cause interference.

You should always consider ceiling or wall-mounting your access points, because it is usually easie to deploy.  Many times, even deciding if you are a good candidate for floor-mounted ceilings is an advanced topic and should only be done by a trained professional.  You can normally get just as good results with wall or ceiling-mounted APs.  We have seen locations where 75 users are associated to an AP225 without issues when they are using well-behaved applications like web and email.  The AP115 could probably take 50 to 60 with well-behaved applications like web and email.

Hi cjoseph,

Was just reading your suggestion on high density wireless design to OP's auditorium design and noticed you've mentioned;

"you should have no more than 9 access points in the space, because there are no more than 9 non-overlapping channels in the 5ghz band at 20mhz."

Now I understand why you mentioned no more than 9 access points due to 9 being the max non-overlapping channels available in the 5GHz band.

My question is provided that this is a very high density area of a small space, would it be better to operate 9 APs on 20mhz or fewer APs with channel bonding?

My understanding is the faster the end user device is able to finish transmitting data to the AP the faster the next device can start transmitting which is related to the speed of the 802.11 protocol being used.

So is it better to have more lanes but slower speeds on all the lanes or is it better to have less lanes but faster speeds on each of the lanes?

I also made those comments in 2015, when few clients supported DFS channels universally.  The forum software unfortunately does not have an option to auto-close threads that are old, so this is old information.

Please consult the updated VRD here:  https://community.arubanetworks.com/t5/Validated-Reference-Design/RF-and-Roaming-Optimization-for-Aruba-802-11ac-Networks/ta-p/432994 for more information.