HTC Sensation XE, Mobile data OFF when GPS ON

When any app on my android device started to read GPS (with GPS icon ON at notification area), my mobile data connection is OFF right away and then ON again after about 10-20 seconds. It happens in every app and that's really annoys me. I've tried to uncheck the "Google's Location Service" at "Location" settings menu, but it affects nothing. Anyone has same problem with me? What's the solutions?