Do you know which users are experiencing issues ? if you do then you could look those up in airwave and see what APs are those users have connected to and then you can run the following :
This will tell how close that rogue device is based on the RSSI values
(controller) #show ap monitor ap-list ap-name Test_125_2
Monitored AP Table
------------------
bssid essid chan ap-type phy-type dos dt/mt ut/it encr nstas avg-rssi curr-rssi wmacs ibss
----- ----- ---- ------- -------- --- ----- ----- ---- ----- -------- --------- ----- ----
c0:c1:c0:34:2b:20 rogue 6 interfering 80211b/g-HT-20 disable 10915/269 4/0 open 0 23 22 0 no
d8:c7:c8:88:99:44 test_ssid 6 valid 80211b/g-HT-20 disable 10856/269 43/2 wpa2-8021x-aes 1 31 31 1 no
You can also run the following to see if the Interference Index or noise level are high on the channel assigned to that AP
(controller) # show ap arm rf-summary ap-name Test_125_2
Channel Summary
---------------
channel retry phy-err mac-err noise util(Qual) cov-idx(Total) intf_idx(Total)
------- ----- ------- ------- ----- ---------- -------------- ---------------
36 0 0 0 89 1/0/1/0/97 6/0(6) 0/0//0/0(0)
40 0 0 0 88 5/0/2/0/97 0/0(0) 0/9//0/0(9)
44 0 0 0 93 8/2/2/0/94 3/0(3) 28/12//0/0(40)
48 0 0 0 89 8/2/2/0/96 7/0(7) 37/9//0/0(46)
149 0 0 0 93 3/0/0/0/96 0/0(0) 0/0//0/0(0)
153 0 0 0 93 5/0/2/1/97 0/0(0) 0/16//0/0(16)
157 0 0 0 93 8/2/2/0/96 10/0(10) 51/0//0/0(51)
161 0 0 0 91 5/0/2/3/97 0/0(0) 0/15//0/0(15)
165 0 0 0 96 5/0/2/0/97 0/0(0) 0/0//0/0(0)
1 0 0 0 90 28/21/5/0/90 8/0(8) 82/24//0/0(106)
6 0 0 0 88 22/17/0/7/64 25/0(25) 149/34//0/0(183)
11 0 0 2 92 16/9/5/0/98 7/0(7) 122/24//0/0(146)
Columns:util(Qual): ch-util/rx/tx/ext-ch-util/quality
HT Channel Summary
------------------
channel_pair Pairwise_intf_index
------------ -------------------
149-153 16
36-40 9
157-161 66
44-48 86
Interface Name :wifi0
Current ARM Assignment :36+/18
Covered channels a/g :3/0
Free channels a/g :5/0
ARM Edge State :disable
Last check channel/pwr :32s/3m:45s
Last change channel/pwr :3h:1m:48s/3h:1m:48s
Next Check channel/pwr :7m:21s/2m:34s
Assignment Mode :Single Band
Interface Name :wifi1
Current ARM Assignment :11/12
Covered channels a/g :0/2
Free channels a/g :0/1
ARM Edge State :disable
Last check channel/pwr :3m:16s/2m:23s
Last change channel/pwr :1h:42m:3s/1h:42m:3s
Next Check channel/pwr :3m:0s/2m:36s
Assignment Mode :Single Band