Patent ID: 8917788

Claim:
A mobile station apparatus which is configured to and/or programmed to use two or more transmission antennas and is configured to and/or programmed to perform communication with a base station apparatus, the mobile station apparatus comprising: a PUSCH (Physical Uplink Shared Channel) transmission part configured to and/or programmed to transmit data through changing at least the number of the transmission antennas and a number of transmission streams to use; and a PH calculation part configured to and/or programmed to calculate a PH (Power Headroom) using a maximum transmit power of the mobile station apparatus, wherein an individual PH for each transmission stream used for transmitting data is calculated by at least subtracting a transmit power actually transmitted through each respective transmission antenna from the maximum transmit power of the mobile station apparatus, thereby providing a PH that represents a headroom for a transmit power relative to the maximum transmit power in a case where one transmission antenna is used, and the PUSCH transmission part is configured to and/or programmed to transmit the PH calculated.