Transmitting apparatus, receiving apparatus, transmitting method and receiving method that wirelessly communicate with each other using plurality of antennas

A receiving apparatus comprising:

• a receiver configured to receive a signal from a transmitting apparatus via a plurality of antennas, wherein the transmitting apparatus derives a singular value matrix which is a diagonal matrix where singular values are arranged, and a weight matrix which is a unitary matrix corresponding to the singular value matrix, by subjecting a channel matrix to singular value decomposition, the channel matrix having elements that represent channel characteristics between a plurality of antennas at a transmitting side and the plurality of antennas at a receiving side, respectively, and wherein, when a degree of difference between the singular values arranged in the single value matrix lies within a predetermined range, the transmitting apparatus weights the signal with a transmission weight vector contained in the weight matrix;
• a derivation unit configured to derive a receiving weight vector based on the signal received by the receiver;
• and
• a processing unit configured to perform array synthesis on the signal received by the receiver, using the receiving weight vector derived by the derivation unit,
• wherein, when the degree of difference between the singular values arranged in the single value matrix lies outside predetermined range, the receiver receives a signal computed with the transmission weight vector and a correction matrix,
• wherein, when the degree of difference between the singular values arranged in the single value matrix lies outside predetermined range, the derivation unit stops deriving the receiving weight vector, and
• wherein, when the degree of difference between the singular values arranged in the single value matrix lies outside the predetermined range, the processing unit performs array synthesis on the signal received by the receiver, using the receiving weight vector derived previously by the derivation unit.

A transmitting method comprising:

• acquiring a channel matrix, having elements that represent channel characteristics between a plurality of antennas at a transmitting side and a plurality of antennas at a receiving side, respectively;
• deriving a singular value matrix that is a diagonal matrix where singular values are arranged, by subjecting the channel matrix acquired to singular value decomposition, and deriving a weight matrix which is a unitary matrix corresponding to the singular value matrix;
• deriving a degree of difference between the singular values arranged in the singular value matrix derived;
• determining whether or not the degree of difference lies within a predetermined range;
• and
• transmitting, from the plurality of antennas, a result of computation of a weight vector, contained in the weight matrix, and a signal, when the degree of difference lies within the predetermined range, and transmitting, from the plurality of antennas, a result of computation of the weight vector, contained in the weight matrix, the signal, and a correction matrix, when the degree of difference lies outside the predetermined range.

A receiving method comprising:

• receiving a signal from a transmitting apparatus via a plurality of antennas, wherein the transmitting apparatus derives a singular value matrix which is a diagonal matrix where singular values are arranged, and a weight matrix which is a unitary matrix corresponding to the singular value matrix, by subjecting a channel matrix to singular value decomposition, the channel matrix having elements that represent channel characteristics between a plurality of antennas at a transmitting side and the plurality of antennas at a receiving side, respectively, and wherein, when a degree of difference between the singular values arranged in the single value matrix lies within a predetermined range, the transmitting apparatus weights the signal with a transmission weight vector contained in the weight matrix;
• deriving a receiving weight vector based on the received signal;
• and
• performing array synthesis on the received signal, using the receiving weight vector derived,
• wherein, when the degree of difference between the singular values arranged in the single value matrix lies outside predetermined range, the receiving receives a signal computed with the transmission weight vector and a correction matrix,
• wherein, when the degree of difference between the singular values arranged in the single value matrix lies outside the predetermined range, the deriving stops deriving the receiving weight vector, and
• wherein, when the degree of difference between the singular values arranged in the single value matrix lies outside the predetermined range, the performing performs array synthesis on the received signal, using the receiving weight vector derived previously by the derivation unit.