I had issues with my network too, but decided it was the power management setting on the Edimax wifi dongle as mentioned in this thread:
viewtopic.php?f=34&t=423&p=2760&hilit=8192cu#p2760
Step #6 shows adding a configuration file and it seems to be helping. That file would be located here: /etc/modprobe.d/8192cu.conf