Patent ID: 8688137

Claim:
A mobile communication system in which a mobile station apparatus transmits, to a base station apparatus, uplink data on a physical uplink shared channel assigned by using a physical downlink control channel, the mobile communication system comprising: the base station apparatus configured to transmit on the physical downlink control channel, to the mobile station apparatus, information for instructing to transmit reception quality information without the uplink data, and the mobile station apparatus configured to transmit, to the base station apparatus, the reception quality information without the uplink data on the physical uplink shared channel assigned by using the physical downlink control channel in case that the information for instructing to transmit the reception quality information without the uplink data is received on the physical downlink control channel, wherein the information for instructing to transmit the reception quality information without the uplink data is specified by setting each of a plurality of information fields to each of certain values, one of the plurality of information fields is a field for information for instructing to transmit the reception quality information, the field for information for instructing to transmit the reception quality information is set to a first single predetermined value, and another is a field for information for indicating a redundancy version, the field for information for indicating the redundancy version is set to a second single predetermined value.