Many people around the world having Wifi problems with their iPad2. Most of them complain "iPad2 Wifi connection dropping every 15 - 20 minutes" "Icon on the iPad shows connected, but there are no connections"
At first, I have not had this problem with my iPad2. But after 2 weeks, I start to notice it, especially when I have multiple wireless routers, such as home gateway, portable 4G hotspots (Yes Huddle) and 4G home gateway (Yes Zoom)
The problem is, the iPad 2 having problems supporting some wifi hotspot devices, especially those with b/g/n working mode and those auto radio channels switch 1 - 11
How to solve it?
Step 1: On the iPad2, go to Genera > Reset > Rest Network Settings
Step 2: On the iPad2, Go to Wi-Fi>Choose a Network… If you still see your iPad connected to you network AP, tap on the little blue arrow on the right and tap on Forget this Network. Else, Skip this step
Step 3: Login to your router/hotspot. Usually http://192.168.1.1 (This is the address for all Yes hotspot)
Step 4: Under Wi-Fi settings, Set Radio Channel to between 5 - 9 (Default is Auto)
Step 5: Security change to "WPA2"
Step 6 (Optional): Working mode (Default is 802.11b/g/n for newer hotspots) you might one to try the combination of b/g or b/n depends on which works.
Step 7: Reboot the hotspot
Step 8: from the iPad2, connect to your hotspot again.
This should solve the random disconnecting issue. It solved mine.
But if you are using Apple Airport Extreme at home… You will not get this problem.