Here are a couple of settings I recommend having a look at when configuring WLAN on your Cisco WLC.
The first setting to have a look at relates to a re-authentication timeout for users that are not currently active on the network. i.e. device has powered off, gone offsite etc.
config network usertimeout <seconds>
The second recommended setting is the sesssion-timeout. The session-timeout value will effect all users if the are active on the network or not and will for the client to re-auth. This setting is set on a per WLAN ID. It becomes especially import when your users are connecting via a captive portal network.
config wlan session-timeout <WLAN ID> <seconds>
