Wireless communications system, wireless communications apparatus, wireless communications method and computer program for wireless communication
In performing SVD-MIMO transmission, a set-up procedure is simplified while assuring a satisfactory decoding capability with a reduced number of antennas. A transmitter estimates channel information based on reference signals sent from a receiver, determines a transmit antenna weighting coefficient matrix based on the channel information, calculates a weight to be assigned to each of components of a multiplexed signal, and sends, to the receiver, training signals for respective signal components, the training signals being weighted by the calculated weights. On the other hand, the receiver determines a receive antenna weighting coefficient matrix based on the received training signals.
1. A wireless communication apparatus for transmitting a signal by multiplexing the signal using a plurality of antennas, the apparatus comprising:
circuitry configured to:
acquire feedback information corresponding to a characteristic of a channel linking the apparatus to a receiver;
determine a weighting coefficient matrix for each of the plurality of antennas based on the acquired feedback information; and
control transmission of training signals to the receiver, the training signals being weighted by weights included in the weighting coefficient matrix and intended for channel estimation at the receiver, wherein the number of training signals is determined according to the number of antennas.
2. The wireless communication apparatus of claim 1 , wherein the training signals are used for channel estimation at the receiver.
3. The wireless communication apparatus of claim 1 , wherein
the circuitry is configured to calculate weights included in the weighting coefficient matrix.
4. The wireless communication apparatus of claim 1 , wherein
the circuitry is configured to calculate a weight to be assigned to each component of the signal multiplexed at the transmitter.
5. The wireless communication apparatus of claim 1 , wherein the training signals are compensated by using a calibration coefficient.
6. The wireless communication apparatus of claim 1 , wherein the number of training signals is equal to the number of antennas.
7. The wireless communication apparatus of claim 1 , wherein the feedback information is compressed.
8. The wireless communication apparatus of claim 1 , wherein the feedback information is channel information.
9. The wireless communication apparatus of claim 1 , wherein the training signals each include a consecutive sequence of bits.
10. The wireless communication apparatus of claim 1 , wherein the training signals for each of the respective antennas include a different consecutive sequence of bits.