Wireless Access

Got an area where we have 4 AP635s. We have users reporting that they have poor connection resulting in slow speeds, dropped calls, etc. We went over and tested signal strength and speed tests, and not seeing any obvious issues.

We run airwave and dual 7220 controllers. How can I begin to troubleshoot? Is there somewhere in either of these devices that we could see something causing interference?  I do see some rogue devices reported on those APs, but not sure how to diagnose further.

It would be worth seeing if you can experience the issue alongside the user reporting it. The issue may be specific to their device which is why when you run tests you don't see anything obvious. Confirm the scope of the issue by checking that the issue only exists in the particular area. Does the user experience similar problems elsewhere on the network?
Is the user connected to a particular Wi-Fi band (2.4 GHz, 5 GHz or 6 GHz)?
Are the issues only experienced at a certain time such as when the area is particular busy with lots of users? Or maybe when the overall Internet use is high and congestion occurs elsewhere?
Are other users in this area experiencing issues at the same time or is the problem specific to a particular user?

Are there any other networks operating in the area on the same channels? Check the rogue networks in AirWave.
How many other users are connected to the AP with the user experiencing issues?
Check AirWave for overall channel utilisation in this area.

Check the other points on the network for congestion such as upstream switches or Internet.
Check the APs are connected at at least 1 Gbps to the local switch.

Make sure the user is in fact connected to the expected APs in that area and not sticking to an AP further away.

Hopefully some of these are useful points for diagnosis and lead you on a successful path to resolution.