RADIO COMMUNICATION SYSTEM, BASE STATION DEVICE, MOBILE STATION DEVICE, AND RADIO COMMUNICATION METHOD

摘要

PROBLEM TO BE SOLVED: To enable a mobile station device to determine an uplink carrier element supported by a downlink control channel which gives an instruction to start random access processing.SOLUTION: A base station device sets two sets, which are composed of physical random access channel resources and are included in different uplink component carriers, in a mobile station device, and transmits information about instruction to start random access processing to the mobile station device by using one downlink component carrier. The mobile station device transmits a preamble by using one physical random access channel resource between the two sets on the basis of the information received from the base station device.