A communication device for handling a signal transmission on an unlicensed component carrier (CC) comprises a storage unit for storing instructions and a processing means coupled to the storage unit. The processing means is configured to execute the instructions stored in the storage unit. The instructions comprise detecting at least one first signal transmitted by at least one base station on an unlicensed CC; determining at least one first time interval where the at least one first signal is transmitted by the at least one base station; and transmitting at least one second signal on the unlicensed CC in at least one second time interval to a communication device wherein the at least one second time interval is not overlapped with the at least one first time interval.