Antenna selection method and radio communication device

An antenna selection method used in a MIMO (Multi Input Multi Output) radio communication system, comprising:

• a first step of selecting columns corresponding to already selected I−1 emission antennas (where I is a natural number greater than 0) from an M-column channel estimation matrix composed of all of M transmitting antennas (where M is a natural number greater than 1) and configuring an I−1-column emission channel matrix;
• a second step of selecting columns corresponding to M−I+1 candidate transmitting antennas other than the I−1 emission antennas from the channel estimation matrix and configuring an M−I+1-column candidate channel matrix;
• a third step of adding one arbitrary column of the candidate channel matrix to the emission channel matrix and configuring M−I+1 selection determination channel matrices;
• a fourth step of performing QR decomposition on the M−I+1 selection determination channel matrices and obtaining M−I+1 upper triangular matrices;
• a fifth step of finding a diagonal element minimum modular value of each of the M−I+1 upper triangular matrices;
• a sixth step of selecting one upper triangular matrix for which the diagonal element minimum modular value is largest from among the M−I+1 upper triangular matrices;
• and
• a seventh step of selecting one the candidate transmitting antenna composing a selection determination channel matrix corresponding to an upper triangular matrix selected in the sixth step as an I'th emission antenna,
• wherein the first step, the second step, the third step, the fourth step, the fifth step, the sixth step, and the seventh step are repeated K times (where K is a natural number greater than 0), and emission antennas are selected one by one up to K emission antennas.

A radio communication apparatus used in a MIMO (Multi Input Multi Output) radio communication system, comprising:

• M transmitting antennas (where M is a natural number greater than 1);
• and
• a selection section that executes selection processing that selects K emission antennas (where K is a natural number greater than 0 and less than or equal to M) from the M transmitting antennas based on an M-column channel estimation matrix composed of all the M transmitting antennas,
• wherein the selection section executes the selection processing that includes:
• a first step of arbitrarily selecting K columns from the channel estimation matrix and configuring CMK selection determination channel matrices;
• a second step of performing QR decomposition respectively on the CMK selection determination channel matrices and obtaining CMK upper triangular matrices;
• a third step of finding a diagonal element minimum modular value of each of the CMK upper triangular matrices;
• a fourth step of selecting one upper triangular matrix for which the diagonal element minimum modular value is largest from among the CMK upper triangular matrices;
• and
• a fifth step of selecting K transmitting antennas composing a selection determination channel matrix corresponding to an upper triangular matrix selected in the fourth step as emission antennas.

A radio communication apparatus used in a MIMO (Multi Input Multi Output) radio communication system, comprising:

• M transmitting antennas (where M is a natural number greater than 1);
• and
• a selection section that executes selection processing that selects K emission antennas (where K is a natural number greater than 0 and less than or equal to M) from the M transmitting antennas based on an M-column channel estimation matrix composed of all the M transmitting antennas, wherein the selection section executes the selection processing that includes:
• a first step of selecting columns corresponding to already selected I−1 emission antennas (where I is a natural number greater than 0) from the channel estimation matrix and configuring an I−1-column emission channel matrix;
• a second step of selecting columns corresponding to M−I+1 candidate transmitting antennas other than the I−1 emission antennas from the channel estimation matrix and configuring an M−I+1-column candidate channel matrix;
• a third step of adding one arbitrary column of the candidate channel matrix to the emission channel matrix and configuring M−I+1 selection determination channel matrices;
• a fourth step of performing QR decomposition on the M−I+1 selection determination channel matrices and obtaining M−I+1 upper triangular matrices;
• a fifth step of finding a diagonal element minimum modular value of each of the M−I+1 upper triangular matrices;
• a sixth step of selecting one upper triangular matrix for which the diagonal element minimum modular value is largest from among the M−I+1 upper triangular matrices;
• and
• a seventh step of selecting one the candidate transmitting antenna composing a selection determination channel matrix corresponding to an upper triangular matrix selected in the sixth step as an I'th emission antenna, and
• repeats the first step, the second step, the third step, the fourth step, the fifth step, the sixth step, and the seventh step K times (where K is a natural number greater than 0) and selects emission antennas one by one up to K emission antennas.