An embodiment of a relay station for a base station and a mobile station is provided. The relay station includes a first base station module and a mobile station module. The first base station module receives a control packet and a data packet transmitted by a mobile station. The mobile station module receives and transmits the control packet and the data packet to the base station, wherein the first base station module transmits the control packet to the mobile station module via a tunnel mode, and transmits the data packet to the mobile station module via a bridge mode.