The latest system update to some of the 4G LTE Phones (Droid Bonic and Driod 4 for sure) have added some task that task killers kill off, causing the loss of 4G LTE connections.  We were using Advanced Task Killer and connection dropped as soon as it came back up with ATK installed.  After un-installing ATK, connection has been back to solid 4G LTE.

(This is in Virginia Beach)

If you're using a task killer of any kind, especially Advanced Task Killer... Try un-installing it completely and see if that resolves your problem with your data connection.  It seems to have worked on both phones for us.