have xperia ION LT28h with ICS, i am facing wiered issue.

Issue discription :

When i have network data on and if i lose the network (e.g in lift) and when i get the network connection back, the network data doesnt come back automatically even though it is on.Even if i turn off and and turn on the network data it doesnt connect. i can call and receive calls so its not network problem. i have tried switching on airoplane mode and switching back off , connecting to wifi and disconnecting again, i have turned off data Limit but none work. i have to restart the phone and then only it connects to network data again.i have tried to repair the software and still facing the issue.

Highly appriciate any inputs.