I have inhereted a network with several Aruba APs (215 and 315s). There are 5 of them in a warehouse space and the users connect to them with handheld scan guns. We have under 15 wireless devices total and even when they are standing directly under the APs they get some lag and disconnected a lot.
It looks like signal and speed are very low on all of the devices and I really dont even know where to start. Granted the ceiling is high (maybe 18-24') but when they are standing slear line of sight I would think it would not have the issue.