Hardware

Just installed DWA 520 wireless interface in my m0n0 and found this problem:
When it switched to IBSS mode everything works fine except my PlayStation portable that can't connect to ad-hoc networks.
When it switched to hostap all devices with 802.11g interfaces can be connected, but in a few seconds they almost loosing that connection. If I connect PSP which has 802.11b interface and hasn't power management functionality - all the devices seems to work. But There are still some losses that was not seen in IBSS.

Can somebody tell me how to fix it? Please.