TP-LINK TL-WN821N automatically disconnects

I have a problem with my usb wireless stick (TP-LINK TL-WN821N) when I'm surfing on the net or something like that, so in every ~30 minutes I get disconnected from the internet, unfortunatly whent it happens I always have to unplug and then connect this usb device so that I can connect to the internet again.

ps: under windows it works properly and under the previous version of ubuntu

I suggest you to do the trick proposed in the comment 13 of this Launchpad bug, that is to blacklist the ar9170usb driver:

https://bugs.launchpad.net/ubuntu/+source/linux-backports-modules-2.6.32/+bug/495562

This seems to be a driver bug. See the official documentation for that card:

• https://help.ubuntu.com/community/HardwareSupportComponentsWirelessNetworkCardsTP-Link

And the bug reports in launchpad:

• https://bugs.launchpad.net/ubuntu/+source/linux/+bug/540827
• https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/549140

Some fixes / workarounds are described. Disabling the N-thingy seemed to work accoding to this answer:

• Wireless Internet Extremely slow on a TP-Link TL-WN821N