Patent ID: 8649357

Claim:
A mobile station apparatus which has two or more transmission antennas and performs wireless communications with a base station apparatus, the mobile station apparatus comprising: a PUSCH (Physical Uplink Shared Channel) transmission part configured to transmit data through changing the number of the transmission antennas to use; and a PH calculation part configured to calculate PH (Power Headroom) using a maximum transmit power of the mobile station apparatus and a transmit power to achieve requested reception power in the base station apparatus, wherein the PH calculation part is configured to calculate the PH using a predetermined value as the maximum transmit power of the mobile station apparatus, where the predetermined value in the case of transmitting by using the two or more transmission antennas is equal to the predetermined value in the case of transmitting by using a single transmission antenna, and wherein the PUSCH transmission part is configured to transmit the PH calculated.