Wireless communication system
First Claim
1. A wireless communication system in which a transmitter having a plurality of antennas and a receiver having a plurality of antennas form a pair and spatially multiplex and communicate a signal, the wireless communication system comprising:
- a closed-loop spatial multiplexing communication mode in which the transmitter transmits a signal for acquiring channel information to the receiver and the receiver sends feedback of the channel information to the transmitter;
an open-loop spatial multiplexing communication mode in which only the transmitter transmits a signal for acquiring channel information to the receiver; and
a mode switcher configured to switch between the closed-loop spatial multiplexing communication mode and the open-loop spatial multiplexing communication mode, and switch to the open-loop spatial multiplexing communication mode in response to information indicating that an amount of data to be transmitted has exceeded a predetermined data limit or a transmission time during data transmission under the closed-loop spatial multiplexing communication mode has exceeded a predetermined time limit.
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Abstract
In order to transmit a large amount of data in series at a time with a MIMO communication scheme while avoiding deterioration of decoding characteristics due to change over time by a channel matrix, a wireless communication system uses an open-loop type and a closed-loop type of MIMO communication modes in combination and switches to the open-loop MIMO communication mode in response to the information that the amount of data to be transmitted at a time has exceeded a predetermined amount of bits or a predetermined transmission time during data transmission under the closed-loop MIMO communication mode. By discontinuing useless closed-loop MIMO communication and switching to the open-loop MIMO communication mode that is better than Zero-forcing, the decoding characteristics are prevented from simply becoming deteriorated.
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Citations
92 Claims
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1. A wireless communication system in which a transmitter having a plurality of antennas and a receiver having a plurality of antennas form a pair and spatially multiplex and communicate a signal, the wireless communication system comprising:
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a closed-loop spatial multiplexing communication mode in which the transmitter transmits a signal for acquiring channel information to the receiver and the receiver sends feedback of the channel information to the transmitter; an open-loop spatial multiplexing communication mode in which only the transmitter transmits a signal for acquiring channel information to the receiver; and a mode switcher configured to switch between the closed-loop spatial multiplexing communication mode and the open-loop spatial multiplexing communication mode, and switch to the open-loop spatial multiplexing communication mode in response to information indicating that an amount of data to be transmitted has exceeded a predetermined data limit or a transmission time during data transmission under the closed-loop spatial multiplexing communication mode has exceeded a predetermined time limit. - View Dependent Claims (2, 3, 4, 5)
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6. A wireless communication system in which a transmitter having a plurality of antennas and a receiver having a plurality of antennas form a pair and spatially multiplex and communicate a signal, the wireless communication system comprising:
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a closed-loop spatial multiplexing communication mode in which the transmitter transmits a signal for acquiring channel information to the receiver, the receiver sends feedback of the channel information to the transmitter, the receiver finds a channel matrix H by receiving a reference signal sent from the transmitter, obtains a reception weight matrix UH, a diagonal matrix D and a transmission weight matrix V by performing singular value decomposition of the channel matrix H into UDVH, and sends feedback of the transmission weight matrix V to the transmitter, there is performed Singular Value Decomposition-Multiple Input Multiple Output (SVD-MIMO) communication in which the transmitter performs weighted transmission with the transmission weight matrix V and the receiver performs weighted reception with the reception weight matrix UH; an open-loop spatial multiplexing communication mode in which only the transmitter transmits a signal for acquiring channel information to the receiver; and a mode switcher configured to switch between the closed-loop spatial multiplexing communication mode and the open-loop spatial multiplexing communication mode, and switch to the open-loop spatial multiplexing communication mode in response to the information that the transmission weight matrix V obtained by the singular value decomposition has changed beyond a predetermined value during data transmission under the closed-loop spatial multiplexing communication mode.
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7. A wireless communication apparatus having a plurality of antennas that spatially multiplexes and transmits a signal to a receiver having a plurality of antennas, the wireless communication apparatus comprising:
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a closed-loop spatial multiplexing communication mode in which the apparatus performs weighted transmission based on feedback information from the receiver; an open-loop spatial multiplexing communication mode in which the apparatus performs non-weighted transmission; and a mode switcher configured to switch between the closed-loop spatial multiplexing communication mode and the open-loop spatial multiplexing communication mode, and switch to the open-loop spatial multiplexing communication mode in response to information indicating that an amount of data to be transmitted has exceeded a predetermined data limit or a transmission time during data transmission under the closed-loop spatial multiplexing communication mode has exceeded a predetermined time limit. - View Dependent Claims (8)
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9. A wireless communication apparatus having a plurality of antennas that spatially multiplexes and transmits a signal to a receiver having a plurality of antennas, the wireless communication apparatus comprising:
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a closed-loop spatial multiplexing communication mode in which the apparatus performs weighted transmission based on feedback information from the receiver; an open-loop spatial multiplexing communication mode in which the apparatus performs non-weighted transmission; and a mode switcher configured to switch between the closed-loop spatial multiplexing communication mode and the open-loop spatial multiplexing communication mode, and switch to the open-loop spatial multiplexing communication mode in response to the information from the receiver that a mode has been switched to the open-loop spatial multiplexing communication mode.
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10. A wireless communication apparatus having a plurality of antennas that spatially multiplexes and transmits a signal to a receiver having a plurality of antennas, the wireless communication apparatus comprising:
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a closed-loop spatial multiplexing communication mode in which the apparatus performs weighted transmission based on feedback information from the receiver; an open-loop spatial multiplexing communication mode in which the apparatus performs non-weighted transmission; a mode switcher configured to switch between the closed-loop spatial multiplexing communication mode and the open-loop spatial multiplexing communication mode; a feedback information receiving section configured to receive feedback information for acquiring a transmission weight matrix V from the receiver and perform Singular Value Decomposition-Multiple Input Multiple Output (SVD-MIMO) transmission of weighted transmission by the transmission weight matrix V under the closed-loop spatial multiplexing communication mode; and a transmitting section configured to transmit data to which the apparatus does not apply the transmission weight V under the open-loop spatial multiplexing communication mode.
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11. A wireless communication apparatus having a plurality of antennas that receives a multiplexed signal from a transmitter having a plurality of antennas, the wireless communication apparatus comprising:
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a closed-loop spatial multiplexing communication mode in which the apparatus sends feedback of channel information to the transmitter, finds a channel matrix H by receiving a reference signal sent from the transmitter, obtains a reception weight matrix UH, a diagonal matrix D and a transmission weight matrix V by performing singular value decomposition of the channel matrix H into UDVH, and performs Singular Value Decomposition-Multiple Input Multiple Output (SVD-MIMO) communication using weighted reception with the reception weight matrix UH and sends feedback of the transmission weight matrix V to the transmitter; an open-loop spatial multiplexing communication mode in which the apparatus does not send feedback of channel information to the transmitter; and a mode switcher configured to switch between the closed-loop spatial multiplexing communication mode and the open-loop spatial multiplexing communication mode, and switch to the open-loop spatial multiplexing communication mode in response to the information that the transmission weight matrix V obtained by the singular value decomposition has changed beyond a predetermined value during data transmission under the closed-loop spatial multiplexing communication mode.
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12. A wireless communication apparatus having a plurality of antennas that receives a multiplexed signal from a transmitter having a plurality of antennas, the wireless communication apparatus comprising:
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a closed-loop spatial multiplexing communication mode in which the apparatus sends feedback of channel information to the transmitter; an open-loop spatial multiplexing communication mode in which the apparatus does not send feedback of channel information to the transmitter; and a mode switcher configured to switch between the closed-loop spatial multiplexing communication mode and the open-loop spatial multiplexing communication mode, and inform the transmitter that a mode has been switched to the open-loop spatial multiplexing communication mode. - View Dependent Claims (13)
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14. A wireless communication apparatus having a plurality of antennas that receives a multiplexed signal from a transmitter having a plurality of antennas, the wireless communication apparatus comprising:
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a closed-loop spatial multiplexing communication mode in which the apparatus sends feedback of channel information to the transmitter; an open-loop spatial multiplexing communication mode in which the apparatus does not send feedback of channel information to the transmitter; a mode switcher configured to switch between the closed-loop spatial multiplexing communication mode and the open-loop spatial multiplexing communication mode; and a communication section configured to perform an open-loop spatial multiplexing communication operation other than a communication scheme for providing a reception weight based on an inverse matrix I-V of a channel matrix obtained from a propagation path condition under the open-loop spatial multiplexing communication mode.
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15. A wireless communication method for spatially multiplexing and transmitting a signal to a receiver having a plurality of antennas in a transmitter having a plurality of antennas, the wireless communication method comprising:
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performing closed-loop spatial multiplexing communication based on feedback information from the receiver, the closed-loop spatial multiplexing communication allowing the transmitter to perform weighted transmission; switching to open-loop spatial multiplexing communication in response to information indicating that an amount of data to be transmitted has exceeded a predetermined data limit or a transmission time during data transmission under the closed-loop spatial multiplexing communication mode has exceeded a predetermined time limit; and performing the open-loop spatial multiplexing communication.
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16. A wireless communication method for receiving a multiplexed signal from a transmitter having a plurality of antennas in a receiver having a plurality of antennas, the wireless communication method comprising the steps of:
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performing closed-loop spatial multiplexing communication on the assumption that a transmission weight has been applied by the transmitter, the closed-loop spatial multiplexing communication allowing the receiver to perform weighted reception; switching to open-loop spatial multiplexing communication in response to a change in a reception characteristic, the open-loop spatial multiplexing communication allowing the receiver to perform weighted reception; performing the open-loop spatial multiplexing communication on the assumption that a transmission weight has been applied by the transmitter.
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17. A non-transitory computer-readable medium storing a computer program which when executed on a computer causes the computer to perform processing for spatially multiplexing and transmitting a signal to a receiver having a plurality of antennas from a transmitter having a plurality of antennas, comprising:
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performing closed-loop spatial multiplexing communication based on feedback information from the receiver, the closed-loop spatial multiplexing communication allowing the transmitter to perform weighted transmission; switching to open-loop spatial multiplexing communication in response to information indicating that an amount of data to be transmitted has exceeded a predetermined data limit or a transmission time during data transmission under the closed-loop spatial multiplexing communication mode has exceeded a predetermined time limit; and performing the open-loop spatial multiplexing communication.
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18. A non-transitory computer-readable medium storing a computer program which when executed on a computer causes the computer to perform processing for spatially multiplexing and transmitting a signal to a receiver having a plurality of antennas, in a transmitter having a plurality of antennas, comprising:
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performing closed-loop spatial multiplexing communication by performing weighted transmission based on feedback information from the receiver; performing open-loop spatial multiplexing communication in which the transmitter performs non-weighted transmission; switching between the closed-loop spatial multiplexing communication and the open-loop spatial multiplexing communication, and switching to the open-loop spatial multiplexing communication in response to information from the receiver that a mode has been switched to the open-loop spatial multiplexing communication mode.
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19. A wireless communication apparatus used in a communication system including a transmitter having a plurality of antennas and a receiver having a plurality of antennas, the wireless communication apparatus comprising:
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a receiving unit configured to receive feedback information from the receiver in a closed loop spatial multiplexing communication mode; a transmitting unit configured to transmit a signal in the closed loop spatial multiplexing communication mode and a different spatial coding communication mode in which the feedback information is limited; a switcher configured to switch to the different spatial coding communication mode according to a change in a communication quality. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 58, 59, 60, 61, 62, 63, 65, 66, 67, 68, 69)
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31. A wireless communication apparatus used in a communication system, the wireless communication apparatus comprising:
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a receiving unit configured to receive feedback information from a receiver in a closed loop spatial multiplexing communication mode; a transmitting unit configured to transmit a signal in the closed loop spatial multiplexing communication mode and a different spatial coding communication mode in which the feedback information is limited; a switcher configured to switch to the different spatial coding communication mode according to a failure of communication. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
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42. A wireless communication apparatus used in a communication system including a transmitter having a plurality of antennas and a receiver having a plurality of antennas, the wireless communication apparatus comprising:
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a transmitting unit configured to transmit feedback information in a closed loop spatial multiplexing communication mode; a receiving unit configured to receive a signal in the closed loop spatial multiplexing communication mode and a different spatial coding communication mode in which the feedback information is limited; a switcher configured to switch to the different spatial communication mode in response to a detection of a change in a reception characteristic. - View Dependent Claims (43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56)
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57. A wireless communication method implemented on a wireless communication apparatus used in a communication system, the method comprising:
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receiving feedback information from a receiver in a closed loop spatial multiplexing communication mode; transmitting a signal in one of the closed loop spatial multiplexing communication mode and a different spatial coding communication mode in which the feedback information is limited; switching to the different spatial coding communication mode according to a failure of communication.
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64. A wireless communication method implemented on a wireless communication apparatus used in a communication system including a transmitter having a plurality of antennas and a receiver having a plurality of antennas, the method comprising:
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transmitting feedback information in a closed loop spatial multiplexing communication mode; receiving a signal in one of the closed loop spatial multiplexing communication mode and a different spatial coding communication mode in which the feedback information is limited; switching to the different spatial communication mode in response to a detection of a change in a reception characteristic. - View Dependent Claims (70, 71, 72, 73, 74)
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75. A non-transitory computer readable medium storing a computer program which when executed on a computer causes the computer to perform a wireless communication method implemented on a wireless communication apparatus used in a communication system, the method comprising:
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receiving feedback information from a receiver in a closed loop spatial multiplexing communication mode; transmitting a signal in the closed loop spatial multiplexing communication mode and a different spatial coding communication mode in which the feedback information is limited; switching to the different spatial coding communication mode according to a failure of communication. - View Dependent Claims (76, 77, 78, 79, 80, 81)
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82. A non-transitory computer readable medium storing a computer program which when executed on a computer causes the computer to perform a wireless communication method implemented on a wireless communication apparatus used in a communication system including a transmitter having a plurality of antennas and a receiver having a plurality of antennas, the method comprising:
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transmitting feedback information in a closed loop spatial multiplexing communication mode; receiving a signal in the closed loop spatial multiplexing communication mode and a different spatial coding communication mode in which the feedback information is limited; switching to the different spatial communication mode in response to a detection of a change in a reception characteristic. - View Dependent Claims (83, 84, 85, 86, 87, 88, 89, 90, 91, 92)
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Specification