Patent ID: 8743821

Claim:
A radio communication system comprising: a base station device; and a plurality of mobile station devices each configured to perform radio communication with the base station device, wherein the base station device comprises: a first radio unit configured to select and transmit information indicative of a preamble number of a preamble assigned to one of the plurality of mobile station devices and information indicative of an assignment period of the preamble, the preamble being dedicated for non-contention based random access; and a random access response generator configured to generate a random access response upon receipt of the preamble transmitted from the one of the plurality of mobile station devices, the random access response to be transmitted from the first radio unit, and each of the plurality of mobile station devices comprises: a second radio unit configured to receive and detect the information indicative of the preamble number and the information indicative of the assignment period; a transmitter configured to transmit the preamble corresponding to the preamble number indicated by the received information; and an upper layer processor configured to perform control so as: to retransmit the transmitted preamble in a case that the random access response to the transmitted preamble is not received within a predetermined time window and after the predetermined time window the assignment period that is longer than the predetermined time window has not expired, and not to retransmit the transmitted preamble in a case that the assignment period that is longer than the predetermined time window has expired.