Unreliable wireless connection with an Intel Centrino Advanced-N 6230
You can fix it by running in terminal
sudo tee /etc/modprobe.d/iwlwifi-opt.conf <<< "options iwlwifi 11n_disable=1"
then reboot.
You can revert it by sudo rm /etc/modprobe.d/iwlwifi-opt.conf.
To keep the 802.11n, you can try the 11n_disable=8 option.