It may be power management related. While this is reported to not help with this specific issue and driver, you can give it a whirl anyway.
Originally Posted by 130s
If that does nothing, might as well turn it back on
sudo iwconfig wlan0 power off
It's reported that this driver is still a problem even in the 3.x kernel. But wait, here's where it gets strange. For some reason, there are reports that turning off ACPI "helps". THis is the one single change that I've heard of getting results. The problem is of course, that's not a solution.
sudo iwconfig wlan0 power on
Personally, when dealing with dropping wifi, I take the following approach in this order.
1) Ping and DNS. Can I ping outside of my LAN but domains such as Google.com are hit and miss? Time to start using OpenDNS.
2) Heat. With some chipsets, heat can be an issue. Just for giggles, you might see if a cooling pad helps. If the laptop isn't hot to the touch, then this might not be the issue.
$ sudo cp /etc/resolv.conf /etc/resolv.conf.auto
$ gksudo gedit /etc/dhcp3/dhclient.conf
# append the following line to the document
prepend domain-name-servers 184.108.40.206,220.127.116.11;
# save and exit
3) Another network manager. Even in recent releases of Ubuntu, sometimes I've found that Wicd simply works better with some wireless devices than the default network manager. It's rare, but it happens. http://ubuntuforums.org/showthread.php?t=1680600