If the coneroller does not answer straight away, don't enter the controlled airspace until you have permission. Either
Orbit where you are
Slow down
Zig zag closer to the boundry
Just don't enter without permission
Unless you are told to standby keep calling them until they do answer, if they dont answer ask all stations for a radio check. If no one replies squawk 7600 and go home, and continue making radio calls an ensure you say you are transmitting blind.