Cisco WLC Question... trying to improve 2.4ghz on my campus

Greetings all,

Still working on trying to improve our wireless on our campus. I've gone through multiple rounds with VARs and Cisco Wireless Experts and we've made quite a few adjustments for our residence halls in particular but I'm still getting complaints. I think some of this is simply due to interferers... in some areas I'm seeing 80%+ channel utilization with less than 5% tx and rx on the AP and it's neighbors and with a number of unknown interferers in the area with unknown effect and duty cycles. We won't know for sure until this summer when we can go in with a spectrum analyzer and disable our radios for a clean survey of the air space. Since most of our residence hall APs are in a hallway covering rooms on both sides (not great, I know, but this can't be changed anytime soon), they can see each other as neighbors fairly easily.

 

We don't support 802.11b anymore and that helped, particularly with roaming. A lot of complaints in the residence halls don't really involve a roaming situation though. Our engagements with the experts have indicated the following data rates for 2.4ghz:

 

Data Rate	Support
1 Mbps	Disabled
2 Mbps	Disabled
5.5 Mbps	Disabled
6 Mbps	Disabled
9 Mbps	Disabled
11 Mbps	Supported
12 Mbps	Mandatory
18 Mbps	Supported
24 Mbps	Supported
36 Mbps	Mandatory
48 Mbps	Supported
54 Mbps	Supported

 

Recent attempts to improve the situation have involved reducing the 2.4ghz cell size by modifying the RRM Power Threshold v2 trigger and Maximum Power Level Assignment. I believe, judging by feedback, this had a small positive affect but it wasn't enough yet. We also enabled a 5ghz only SSID but I've already gotten a complaint about that network as well.

 

My second attempt involved adjusting those settings again, this time to increase 2.4ghz cell size, and disable the 2.4ghz radio on every other AP (staggering between floors). We're in the process of seeing how this one plays out although RRM is still keeping the radios power level down so I started looking in to other possibilities.

 

I'd like to disable the 11 Mbps data rate... advice we got previously was to leave it on so clients could drop down to it if necessary but I'm wondering if this isn't part of the issue since as I've read this could be causing a larger cell size for AP neighbor detection. I did try to disable it on one RF profile but got an error saying "Failed to update 11b data rate as 802.11b network is operational"... do I need to disable this data rate in Wireless->802.11b/g/n->Network" first?

 

This is a BYOD environment so I have to support as much as possible, within reason (#sorrynotsorry802.11b). When I look up device info in Prime Infrastructure on some of the tickets I've gotten, connectivity/data rates/SNR/etc usually looks pretty good for the most part. Anyone have any similar experiences or thoughts on this?

 

edit Update to include some additional information... all of our residence halls are utilizing a main SSID broadcasting both 2.4ghz and 5ghz with Band Select enabled (the two residence halls I'm using to test are also broadcasting the second 5ghz only SSID I mentioned above). AP units consist of Cisco 2702i APs and some 702w/1801w deployed where we had to.