This is an ongoing problem that is about to drive me to insanity.
I work in a training centre where we have 30 wireless laptops. Since I started working here in July there has always been the problem that some laptops just drop the connection and cannot find a domain controller.
The only solution, albeit temporary, is to reconnect the laptop to the domain with a patch and reattach to the domain.
I have recently upgraded every wireless card from Ralink 2500 chipset to the Intel 2200BG which has improved things slightly. This week, back feeling positive after xmas, I find we have eight laptops not connecting. I had started reattaching them this afternoon but if I have to keep doing this every couple of weeks I think early retirement might be the only option
We connect to the main school site over a 1.2Gbps fibre - thinking that 30 laptops logging on together was too much for the DC at the other end I installed a DC into the switch here.
We have an Aruba wireless switch and above 5 access points in the building.