Channel feedback for cooperative multipoint transmission
First Claim
1. A method for mobile telecommunication, comprising:
- receiving in a mobile communication terminal downlink signals from at least first and second cells that coordinate transmission of the downlink signals with one another;
in the terminal, calculating channel feedback that is configured, based on the received downlink signals, to be used by the first and second cells in precoding a joint downlink transmission, which is transmitted jointly to the terminal from the first and second cells, the channel feedback calculated in the terminal being such that the first cell is enabled to precode a first signal destined for the terminal using a first precoding vector, the second cell is enabled to precode a second signal that is also destined for the terminal using a second precoding vector that differs in magnitude from the first precoding vector, and the first and second signals convey same data; and
transmitting the channel feedback from the terminal,wherein calculating the channel feedback comprises calculating different first and second recommended magnitudes for the first and second precoding vectors, respectively, and calculating one or more of;
a single-user Channel Quality Indicator (CQI) calculated under a first constraint that no additional downlink signals to other terminals are scheduled simultaneously with the joint downlink transmission addressed to the terminal;
a multi-user CQI calculated under a second constraint that additional downlink signals to one or more other terminals are scheduled simultaneously with the joint downlink transmission addressed to the terminal; and
a non-cooperative-transmission CQI calculated under a third constraint that the first and second cells do not coordinate the transmission with one another.
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Abstract
A method for mobile telecommunication includes receiving in a mobile communication terminal downlink signals from at least first and second cells that coordinate transmission of the downlink signals with one another. Channel feedback is calculated in the terminal based on the received downlink signals. The channel feedback is configured to enable the first cell to precode a first signal destined for the terminal in response to the channel feedback with a first precoding vector, and to enable the second cell to precode a second signal destined for the terminal in response to the channel feedback with a second precoding vector that differs in magnitude from the first precoding vector. The first and second signals convey same data. The channel feedback is transmitted from the terminal. Calculating the channel feedback includes calculating one or more of a single-user Channel Quality Indicator (CQI), a multi-user CQI, and a non-cooperative-transmission CQI.
233 Citations
16 Claims
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1. A method for mobile telecommunication, comprising:
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receiving in a mobile communication terminal downlink signals from at least first and second cells that coordinate transmission of the downlink signals with one another; in the terminal, calculating channel feedback that is configured, based on the received downlink signals, to be used by the first and second cells in precoding a joint downlink transmission, which is transmitted jointly to the terminal from the first and second cells, the channel feedback calculated in the terminal being such that the first cell is enabled to precode a first signal destined for the terminal using a first precoding vector, the second cell is enabled to precode a second signal that is also destined for the terminal using a second precoding vector that differs in magnitude from the first precoding vector, and the first and second signals convey same data; and transmitting the channel feedback from the terminal, wherein calculating the channel feedback comprises calculating different first and second recommended magnitudes for the first and second precoding vectors, respectively, and calculating one or more of; a single-user Channel Quality Indicator (CQI) calculated under a first constraint that no additional downlink signals to other terminals are scheduled simultaneously with the joint downlink transmission addressed to the terminal; a multi-user CQI calculated under a second constraint that additional downlink signals to one or more other terminals are scheduled simultaneously with the joint downlink transmission addressed to the terminal; and a non-cooperative-transmission CQI calculated under a third constraint that the first and second cells do not coordinate the transmission with one another. - View Dependent Claims (2, 3, 4, 5, 6)
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7. Apparatus, comprising:
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a receiver, which is configured to receive downlink signals from at least first and second cells that coordinate transmission of the downlink signals with one another; control circuitry, which is configured to calculate channel feedback that is configured, based on the received downlink signals, to be used by the first and second cells in precoding a joint downlink transmission, which is transmitted jointly to the apparatus from the first and second cells, such that the first cell is enabled to precode a first signal destined for the apparatus using a first precoding vector, the second cell is enabled to precode a second signal that is also destined for the apparatus using a second precoding vector that differs in magnitude from the first precoding vector, and the first and second signals convey same data; and a transmitter, which is configured to transmit the channel feedback, wherein the control circuitry is configured to calculate the channel feedback by calculating different first and second recommended magnitudes for the first and second precoding vectors, respectively, and calculating one or more of; a single-user Channel Quality Indicator (CQI) calculated under a first constraint that no additional downlink signals to other receivers are scheduled simultaneously with the joint downlink transmission addressed to the receiver; a multi-user CQI calculated under a second constraint that additional downlink signals to one or more other receivers are scheduled simultaneously with the joint downlink transmission addressed to the receiver; and a non-cooperative-transmission CQI calculated under a third constraint that the first and second cells do not coordinate the transmission with one another. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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15. A method for mobile telecommunication, comprising:
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receiving in a mobile communication terminal a Joint-Processing (JP) transmission in which same data is transmitted simultaneously to the terminal by at least first and second cells; in the terminal, calculating based on the received JP transmission channel feedback that is configured to be used by the first and second cells in precoding a subsequent JP transmission, which is transmitted jointly to the terminal from the first and second cells, the channel feedback calculated in the terminal being such that the first cell is enabled to precode a first signal destined for the terminal using a first precoding vector, the second cell is enabled to precode a second signal that is also destined for the terminal using a second precoding vector that differs in power level from the first precoding vector, and the first and second signals convey the same data; and transmitting the channel feedback from the terminal, wherein calculating the channel feedback comprises calculating different first and second recommended power levels for the first and second precoding vectors, respectively, and calculating one or more of; a single-user Channel Quality Indicator (CQI) calculated under a first constraint that no additional downlink signals to other terminals are scheduled simultaneously with the JP transmission addressed to the terminal; a multi-user CQI calculated under a second constraint that additional downlink signals to one or more other terminals are scheduled simultaneously with the JP transmission addressed to the terminal; and a non-cooperative-transmission CQI calculated under a third constraint that the first and second cells do not coordinate the transmission with one another. - View Dependent Claims (16)
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Specification