Mac won't connect to wifi after sleep?

Hello,

I'm a student, and currently on an Enterprise network, and whenever I've used this wifi I always have troubles with connection! The first time I connect at the start of the school year, everything works just fine. However, 90% of the time, after closing the laptop and opening it again, I lose my connection to the wifi - even if I haven't moved.

When I open the laptop it tries to connect to the wifi, and fails. Sometimes it says I have an ip but wont be able to connect, or flat out it cannot connect. Typically I go into my wifi settings and delete the network from the list, then delete the network certificate from my keychain. After turning the wifi off then on, then re-entering my cridentials it will sometimes recconect just fine. Otherwise I have to sit there and connect/dissconecct/wifi on/wifi off till it can connect again. All said and done, getting it to connect again takes me a good 5 mins or so. Not ideal for a college student.

I do NOT have this problem on my home network or any other wifi for that matter, just the schools Enterprise network. I was using Lion up untill today when I upgraded to Mountain Lion, but both OS's have this problem.

Most of my PC peers or Snow Leopard peers have to configure 802.1x settings, however, lion and up does not allow for adding an 802.1x profile. Could this be the source of my problem?

Thanks for any help.