Radio communication system, base station device, mobile station device, and random access method

A mobile station device configured to perform a random access procedure using a dedicated preamble for non-contention based random access assigned by a base station device, the mobile station device comprising:

• an upper layer processor configured to perform a first random access procedure using the dedicated preamble for non-contention based random access on a first available random access channel of a plurality of random access channels in time domain within a period that the dedicated preamble is valid, wherein
• in a case that a random access response to the transmitted preamble is not received within a predetermined time window monitoring for the random access response, the upper layer processor is configured to perform a second random access procedure using the dedicated preamble for non-contention based random access on the first available random access channel of the plurality of random access channels in time domain after the predetermined time window has expired;
• and
• a transmitter configured to transmit the dedicated preamble on a random access channel allowed to transmit by the base station device, wherein
• any one of the plurality of random access channels in frequency domain is allowed to be transmitted by the base station device over a period of time that the plurality of random access channels in frequency domain are allocated to a single carrier.