Radio base station, user terminal and radio communication method
First Claim
1. A radio base station that transmits a data signal to a user terminal by applying beamforming using a plurality of antenna elements,the radio base station comprising:
- a processor that;
determines a type of a weight to apply to the data signal for beamforming;
generates a reference signal which the user terminal uses in channel estimation; and
controls weights to apply to transmitting signals; and
a transmitter that transmits the data signal and the reference signal,wherein the processor determines whether or not to apply a weight to the reference signal based on the type of the weight that is output from a memory, andwherein the type of the weight indicates a fixed weight to define a predetermined weight in advance and an adaptive weight to generate a weight based on channel state information transmitted from the user terminal.
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Accused Products
Abstract
The present invention is designed so that, in a communication system to employ massive MIMO, data signals to which beamforming is applied can be transmitted adequately. A radio base station transmits a data signal to a user terminal by applying beamforming using a plurality of antenna elements, and has a determining section that determines the type of a weight to apply to the data signal for beamforming, a generating section that generates a reference signal which the user terminal uses in channel estimation, a weight control section that controls weights to apply to transmitting signals, and a transmitting section that transmits the data signal and the reference signal, and the weight control section determines whether or not to apply a weight to the reference signal based on the type of the weight.
10 Citations
12 Claims
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1. A radio base station that transmits a data signal to a user terminal by applying beamforming using a plurality of antenna elements,
the radio base station comprising: -
a processor that; determines a type of a weight to apply to the data signal for beamforming; generates a reference signal which the user terminal uses in channel estimation; and controls weights to apply to transmitting signals; and a transmitter that transmits the data signal and the reference signal, wherein the processor determines whether or not to apply a weight to the reference signal based on the type of the weight that is output from a memory, and wherein the type of the weight indicates a fixed weight to define a predetermined weight in advance and an adaptive weight to generate a weight based on channel state information transmitted from the user terminal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 11, 12)
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9. A user terminal that receives a data signal to which beamforming is applied and which is transmitted from a radio base station comprising a plurality of antenna elements, the user terminal comprising:
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a receiver that receives a reference signal transmitted from the radio base station that determines whether or not to apply a weight to the reference signal based on a type of a weight; a processor that; acquires channel state information based on the reference signal; generates a receiving weight based on the channel state information and causes a memory to store the receiving weight; and controls feedback of the channel state information based on a type of the reference signal transmitted from the radio base station wherein the type of the weight indicates a fixed weight to define a predetermined weight in advance and an adaptive weight to generate a weight based on channel state information transmitted from the user terminal.
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10. A radio communication method for a radio base station that comprises a plurality of antenna elements and a user terminal that receives a data signal to which beamforming is applied and which is transmitted from the radio base station, the radio communication method comprising, in the radio base station, the steps of:
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determining a type of a weight to apply to the data signal for beamforming; generating a reference signal which the user terminal uses in channel estimation; determining whether or not to apply a weight to the reference signal based on the type of the weight; and transmitting the data signal and the reference signal, wherein the type of the weight indicates a fixed weight to define a predetermined weight in advance and an adaptive weight to generate a weight based on channel state information transmitted from the user terminal, and wherein, when the type of the weight is a fixed weight, the reference signal and the data signal are applied predetermined weights and transmitted, and, when the type of the weight is an adaptive weight, the reference signal is transmitted without being applied beamforming.
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Specification