Base station apparatus, mobile station apparatus and transmission power control method

A base station apparatus comprising:

• a power control matrix generating section configured to generate a power control matrix reflecting average reception power of each of transmission signals from a plurality of transmission antennas;
• an update section configured to update a codebook which beforehand defines a plurality of precoding weights corresponding to the power control matrix;
• a selecting section configured to select precoding weights that maximize throughput or
• reception SINR obtained after combining the transmission signals from the updated codebook;
• and
• a transmission power control section configured to control transmission power of each of the transmission signals corresponding to the precoding weights selected in the selecting section,
• wherein the power control matrix generating section generates the power control matrix which is a diagonal matrix having the dimension corresponding to the number of transmission antennas, and has values calculated on attenuation amounts of the transmission signals from respective transmission antennas in diagonal components of matrix elements.

A mobile station apparatus comprising:

• an average reception power measuring section configured to measure average reception power of each of transmission signals from a plurality of transmission antennas of a base station apparatus;
• a power control matrix generating section configured to generate a power control matrix reflecting the average reception power;
• an update section configured to update a codebook which beforehand defines a plurality of precoding weights corresponding to the power control matrix;
• a selecting section configured to select precoding weights that maximize throughput or reception SINR obtained after combining the transmission signals from the updated codebook;
• and
• a transmission section configured to transmit, to the base station apparatus, information on the average reception power measured in the average reception power measuring section and on the precoding weights selected in the selecting section,
• wherein the power control matrix generating section generates the power control matrix which is a diagonal matrix having the order corresponding to the number of transmission antennas, and has values calculated on attenuation amounts of the transmission signals from respective transmission antennas in diagonal components of matrix elements.

A mobile communication system in which transmission signals are transmitted from a plurality of transmission antennas of a base station apparatus by spatial multiplexing transmission, and a mobile station apparatus divides the transmission signals to obtain a reception signal, comprising:

• the mobile station apparatus having an average reception power measuring section configured to measure average reception power of each of the transmission signals from the plurality of transmission antennas;
• a first precoding weight determining section configured to generate a power control matrix reflecting the average reception power, to update a plurality of beforehand defined precoding weights corresponding to the power control matrix, and to select optimal precoding weights from the updated precoding weights;
• and
• a transmission section configured to transmit, to the base station apparatus, information on the average reception power and on the optimal precoding weights;
• and
• the base station apparatus having a second precoding weight determining section configured to generate a power control matrix reflecting the average reception power transmitted from the mobile station apparatus, to update a plurality of beforehand defined precoding weights corresponding to the power control matrix, and to select optimal precoding weights from the updated precoding weights corresponding to the information on the optimal precoding weights transmitted from the mobile station apparatus;
• and
• a transmission power control section configured to control transmission power of each of the transmission signals corresponding to the precoding weights selected in the second precoding weight determining section,
• wherein the first and second precoding weight determining sections generate the power control matrix which is a diagonal matrix having the order corresponding to the number of transmission antennas of the base station apparatus, and has values calculated on attenuation amounts of the transmission signals from respective transmission antennas in diagonal components of matrix elements.

A transmission power control method in a base station apparatus for transmitting transmission signals from a plurality of transmission antennas to a mobile station apparatus by spatial multiplexing transmission, comprising:

• in the mobile station apparatus,
• measuring average reception power of each of the transmission signals from the plurality of transmission antennas;
• generating a power control matrix reflecting the average reception power, updating a plurality of beforehand defined precoding weights corresponding to the power control matrix, and selecting optimal precoding weights from the updated precoding weights;
• and
• transmitting, to the base station apparatus, information on the average reception power and on the optimal precoding weights;
• and
• in the base station apparatus,
• generating a power control matrix reflecting the average reception power transmitted from the mobile station apparatus, updating a plurality of beforehand defined precoding weights corresponding to the power control matrix, and selecting optimal precoding weights from the updated precoding weights corresponding to the information on the optimal precoding weights transmitted from the mobile station apparatus;
• and
• controlling transmission power of each of the transmission signals corresponding to the selected optimal precoding weights,
• wherein the base station apparatus and the mobile station apparatus generate the power control matrix which is a diagonal matrix having the dimension corresponding to the number of transmission antennas of the base station apparatus, and has values calculated on attenuation amounts of the transmission signals from respective transmission antennas in diagonal components of matrix elements.