âWeâ have a highly dense AP deployment going on right now in our new HQ building to support wireless voice services.
Unfortunately, the AP's were hung only about 35 ft. from each other. There are about 20 AP's per floor in a three floor building. All three floors have one side without a wall. What I am seeing is that all of the AP's power down to level 8 (the lowest), and each of the AP's has around 30 Rx neighbors. If I leave all of the AP's turned on, the utilization per AP is above about 60% - and up to 100% without any clients associated to it. On the middle floor, I've tried turning off every other AP to see what effect that would have, and noticed the utilization dropped significantly (each AP below 50% utilized), but the power levels never increased on the AP's (I'm assuming because of the gazillion neighbors they see). So, I tried to manually increase the power on every other AP to power level 6. Now, of course, the utilization is really high again.
Is this typical for a voice deployment?
Should the AP's be more like 50-60 feet apart?
Any suggestions? (don't put AP's on the 2nd floor - just 1st and 3rd)?
Please see the attachment.
They will stop laughing when it works. I promise.
One of the things I do is set 'mandatory' the data rate 11Mbps, and every thing above that is 'supported'. Everything below 11 is turned off if I can help it. The worst device you have will transmit data at 11Mbps...it doesn't need to go slower. Make it roam to a new AP with the data rate setting and the power setting. (some phones need the 5.5 so try it and see if you can get away with it. This keeps the cells as small as you can get away with (11Mbps).
250 people per floor is a lot. That brings you back up to 11 AP's just for the user density (using a 1:3 ratio of active calls to users)i.e. 250\3 = 83.3 (number of users out of 250 who could realistically be expected to be making an active call at any given time) 84\8 (number of active calls Cisco supports) = 10.5
And Each floor is 250 people! You will be using at least 11 AP's per floor whether you want to or not - now you have to figure out how to shoehorn them in there.
If the clients can hit multiple floors from where they are standing - you have no load balancing anymore. All your math goes out the window. If the floors are identical, I would place the AP's identicaly as the floor above and below. Even with low power, there will be some bleed through. I will put my strongest signal (new radio) right on the strongest bleed (radio from upstairs) giving the client the best shot at associating to the one I want him to associate to. Remember to do your channel allocations vertically as well or else this approach will hurt you.
If any areas are more dense than others, keep that in mind as well.
This deployment will be a good trick. I eagerly await the outcome...