A mobile communications device supporting operation on a first wireless technology and a second wireless technology with a wireless module and a controller module is provided. The wireless module performs wireless transceiving to and from a first base station of a first wireless technology and a second base station of a second wireless technology. The controller module transmits a control message prior to the starting of a uplink transmission period of the first wireless technology via the wireless module to occupy the uplink transmission period of the first wireless technology so as to allow transmission of signals of the second wireless technology during the uplink transmission period of the first wireless technology, wherein the first wireless technology is a long term evolution (LTE) technology and the second wireless technology is a WiFi technology.