Patent ID: 8369269

Claim:
A radio communication system comprising: a base station device; and a plurality of mobile station devices each performing radio communication with the base station device, wherein the base station device comprises: a radio unit that transmits information indicative of the 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 that generates a random access response to the preamble transmitted from the one of the plurality of mobile station devices, the random access response to be transmitted from the radio unit, and each of the plurality of mobile station devices comprises: a radio unit that receives the information indicative of the preamble number and the information indicative of the assignment period; a transmitter that transmits a preamble corresponding to the preamble number indicated by the received information; and an upper layer processor that performs control so as to repeatedly retransmit the transmitted preamble again and again within the assignment period if a random access response to the transmitted preamble is not received within the assignment period indicated by the received information.