Patent ID: 8830905

Claim:
A base station of a radio communications system including a mobile station and the base station configured to communicate with the mobile station, wherein the base station applies a scheduling method to the mobile station, wherein the scheduling method is such that a radio resource is allocated to the mobile station at every constant time period, the base station comprising: a first transmitter configured to perform a first transmission of a first signal at the every constant time period based on the scheduling method; and a second transmitter configured to perform second and subsequent transmissions of the first signal at a predetermined timing when an error occurs in the first transmission, wherein the predetermined timing corresponds to an interval having a predetermined length in a unit of a sub-frame, wherein a starting point of the predetermined timing is a second time point at which a HARQ round trip time (RTT) has elapsed from a first timing of the first transmission, wherein the predetermined length is represented by a DRX retransmission timer, wherein, when a HARQ RTT timer is expired and when the first transmission of the first signal is not correctly decoded, the DRX retransmission timer is activated, and wherein, when the DRX retransmission timer is activated, the second transmitter performs the second transmission of the first signal.