Wireless communications system, wireless communications apparatus, wireless communications method and computer program for wireless communication
First Claim
1. A wireless communication system for a communication between a transmitter and a receiver each having a plurality of antennas, by multiplexing a signal, the system comprising:
- a channel information acquirer which obtains channel information representing a characteristic of a channel linking the transmitter and the receiver based on a reference signal sent to the transmitter from the receiver;
a first matrix determiner which determines a weighting coefficient matrix for the antennas of the transmitter based on the obtained channel information;
a weight calculator which calculates a weight to be assigned to each of components of the signal multiplexed at the transmitter;
a training signal sender which sends training signals for the respective components of the multiplexed signal to the receiver, the training signals being weighted by the weights calculated by the weight calculator; and
a second matrix determiner which determines a weighting coefficient matrix for the antennas of the receiver based on the received training signals,wherein the wireless communications system employs a RTS/CTS function where the transmitter sends a transmission requesting packet RTS (Request To Send) and the receiver sends a confirmation packet CTS (Clear To Send) in response to the RTS, so that the data transfer is initiated when the transmitter receives the CTS,the receiver sends the CTS packet with reference signals included in the CTS packet, andthe transmitter calculates a weight to be assigned to each of components of the multiplexed signal based on the channel information which is obtained based on the reference signals included in the CTS packet, and sends data packet including training signals for respective signal components sent in a multiplexed fashion.
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Accused Products
Abstract
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.
18 Citations
12 Claims
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1. A wireless communication system for a communication between a transmitter and a receiver each having a plurality of antennas, by multiplexing a signal, the system comprising:
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a channel information acquirer which obtains channel information representing a characteristic of a channel linking the transmitter and the receiver based on a reference signal sent to the transmitter from the receiver; a first matrix determiner which determines a weighting coefficient matrix for the antennas of the transmitter based on the obtained channel information; a weight calculator which calculates a weight to be assigned to each of components of the signal multiplexed at the transmitter; a training signal sender which sends training signals for the respective components of the multiplexed signal to the receiver, the training signals being weighted by the weights calculated by the weight calculator; and a second matrix determiner which determines a weighting coefficient matrix for the antennas of the receiver based on the received training signals, wherein the wireless communications system employs a RTS/CTS function where the transmitter sends a transmission requesting packet RTS (Request To Send) and the receiver sends a confirmation packet CTS (Clear To Send) in response to the RTS, so that the data transfer is initiated when the transmitter receives the CTS, the receiver sends the CTS packet with reference signals included in the CTS packet, and the transmitter calculates a weight to be assigned to each of components of the multiplexed signal based on the channel information which is obtained based on the reference signals included in the CTS packet, and sends data packet including training signals for respective signal components sent in a multiplexed fashion. - View Dependent Claims (2, 3, 4, 5)
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6. A wireless communication apparatus for transmitting a signal by multiplexing the signal using a plurality of antennas, the apparatus comprising:
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a channel information acquirer which obtains channel information representing a characteristic of a channel linking the apparatus to a receiver based on reference signals sent to the transmitter from the receiver and estimates the channel information based on reference signals corresponding to respective antennas of the receiver; a matrix determiner which determines a weighting coefficient matrix for transmit antennas based on the obtained channel information; a weight calculator which calculates a weight to be assigned to each of components of the multiplexed signal; and a training signal sender which sends training signals for the respective components of the multiplexed signal to the receiver, the training signals being weighted by the weights calculated by the weight calculator, wherein the wireless communication apparatus employs a RTS/CTS function where a transmitter sends a transmission requesting packet RTS (Request To Send) and initiates a data transfer in response to and upon receiving a confirmation packet CTS (Clear To Send) including the reference signals sent from a receiver, the channel information acquirer calculates a weight to be assigned to each of components of the multiplexed signal based on the channel information which is obtained based on the reference signals included in the CTS packet, and the training signal sender sends a data packet including training signals for respective signal components sent in a multiplexed fashion. - View Dependent Claims (7, 8)
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9. A wireless communication method for transmitting a signal by multiplexing the signal using a plurality of antennas, the method comprising steps of:
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obtaining channel information representing a characteristic of a channel linked to a receiver based on reference signals sent from the receiver to a transmitter; estimating the channel information based on the reference signals corresponding to respective antennas of the receiver; determining a weighting coefficient matrix for transmit antennas based on the obtained channel information; calculating a weight to be assigned to each of components of the multiplexed signal; and sending training signals for the respective components of the multiplexed signal to the receiver, the training signals being weighted by the weights calculated in the calculating step, wherein the method employs a RTS/CTS function where a transmitter sends a transmission requesting packet RTS (Request To Send) and initiates a data transfer in response to and upon receiving a confirmation packet CTS (Clear To Send) including the reference signals sent from a receiver, the step of obtaining the channel information comprises calculating a weight to be assigned to each of components of the multiplexed signal based on the channel information which is obtained based on the reference signals included in the CTS packet, and the step of sending training signals comprises sending a data packet including training signals for respective signal components sent in a multiplexed fashion. - View Dependent Claims (10, 11)
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12. A computer readable medium encoded with a computer readable code, which when executed by a computer causes the computer to perform processing for transmitting a signal from a transmitter to a receiver by multiplexing the signal using a plurality of antennas, the program comprising steps of:
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obtaining channel information representing a characteristic of a channel linked to a receiver based on reference signals sent to the transmitter from the receiver; estimating the channel information based on the reference signals corresponding to respective antennas of the receiver determining a weighting coefficient matrix for transmit antennas based on the obtained channel information; calculating a weight to be assigned to each of components of the multiplexed signal; and sending training signals for the respective components of the multiplexed signal to the receiver, the training signals being weighted by the weights calculated in the calculating step, wherein the method employs a RTS/CTS function where a transmitter sends a transmission requesting packet RTS (Request To Send) and initiates a data transfer in response to and upon receiving a confirmation packet CTS (Clear To Send) including the reference signals sent from a receiver, the step of obtaining the channel information comprises calculating a weight to be assigned to each of components of the multiplexed signal based on the channel information which is obtained based on the reference signals included in the CTS packet, and the step of sending training signals comprises sending a data packet including training signals for respective signal components sent in a multiplexed fashion.
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Specification