Patent ID: 7889130

Claim:
A communication method in a multi-antenna communication apparatus for determining transmission parameters using information obtained by communicating a known symbol between the multi-antenna communication apparatus and one communicating party, the method comprising: a modulation signal generation step of outputting a first transmission modulation signal obtained by modulating first transmission data and outputting a second transmission modulation signal obtained by modulating second transmission data; a transmission step of, in a common frequency band, using weights determined based on the number of all transmission beams that can be transmitted from multiple antennas, generating a first transmission beam from the first transmission modulation signal and a first eigenvector belonging to a maximum eigenvalue amongst eigenvalues determined per transmission beam, generating a second transmission beam from the second transmission modulation signal and a second eigenvector different from the first eigenvector and transmitting a plurality of transmission signals obtained by combining the first transmission beam and the second transmission beam from the multiple antennas to the one communicating party, the eigenvalues being determined per transmission beam based on the information obtained by the communication of the known symbol; a retransmission request signal reception step of receiving a signal requesting a retransmission of at least part of the transmission data; a retransmission modulation signal generation step of, when the data requested for the retransmission includes the first transmission data and the second transmission data, generating a first retransmission modulation signal by modulating first retransmission data, the first retransmission data comprising a bit sequence that at least in part differs from a bit sequence of the first transmission data, and generating a second retransmission modulation signal by modulating second retransmission data, the second retransmission data comprising a bit sequence that at least in part differs from a bit sequence of the second transmission data; and a retransmission step of, using weights determined based on the information obtained by the communication of the known symbol, and a number of transmission beams lower than upon a previous transmission, generating the first transmission beam from the first retransmission modulation signal, generating one of the first transmission beam from the second retransmission modulation signal at a different time from the first retransmission modulation signal and a third transmission beam that is different from the second transmission beam from the second retransmission modulation signal, and transmitting the generated transmission beams to the one communicating party.