I have the same problem. I recently just changed schools and i'm using my school's wireless connection. After every 30mins of me playing online i get signed off but not off psn, just online play, then a message comes up saying: "No network connection detected. You must have an active network connection to play online or over a local network.". Then im able to go right back and then 30mins later that same message comes up. Someone please help, i just want to play COD.