I have to reconnect every 5 minutes

[shengchieh]

First make sure this a software, not hardware, bug.  Try a liveCD/liveDVD/liveUSB of a different distro and  see if you get the same bug.

If so, do you have a different machine to test the wifi.

If not, then the problem is network software.  In that case i suspect the wifi driver is messing up things.  You'll need to post more info for others to help, i.e., post your wifi name and model.

Sheng-Chieh