Apparatus and method for reducing inter-cell interference in multiple input multiple output system
First Claim
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1. A method for operating a serving base station (BS) in a multiple input multiple output (MIMO) system, the method comprising:
- determining at a serving BS whether there is a cell having an updated codebook subset pattern (CSP) among a serving cell and at least one adjacent cell, each of cells having the CSP being different from each other;
transmitting, if it is determined that there is a cell having the updated CSP among the serving cell and the at least one adjacent cell, the updated CSP to an adjacent BS;
acquiring a CSP of at least one cell serviced by the adjacent BS;
transmitting the updated CSP and the acquired CSP and a reference signal for estimating a channel to at least one user equipment (UE) of the serving cell;
receiving, from the UE, at least one multi-cell channel quality indicator (CQI) as a feedback determined by the UE based on information on an inter-cell interference; and
performing downlink scheduling operation based on the multi-cell CQI,wherein the CSP comprises information on subsets of a codebook and a corresponding relationship between each subset and each time and frequency resource,wherein each of the subsets is used to precode data that is transmitted through a time and frequency resource corresponding to each of the subset,wherein each of the codebooks comprises an empty set or a set of one or more precoding vectors, andwherein the inter-cell interference is identified by the UE using codebooks included in the CSP of each cell and information on channels acquired from the reference signal of each cell.
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Abstract
An apparatus and method for operating a Codebook Subset Pattern (CSP) of a Base Station (BS) in a Multiple Input Multiple Output (MIMO) system are provided. The method includes determining whether there is a CSP-updated BS among the BS and adjacent BSs, exchanging the updated CSP between cells if it is determined that there is a CSP-updated BS, and broadcasting the CSP of each cell acquired through the exchange thereby reducing an inter-cell interference in the MIMO system.
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Citations
22 Claims
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1. A method for operating a serving base station (BS) in a multiple input multiple output (MIMO) system, the method comprising:
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determining at a serving BS whether there is a cell having an updated codebook subset pattern (CSP) among a serving cell and at least one adjacent cell, each of cells having the CSP being different from each other; transmitting, if it is determined that there is a cell having the updated CSP among the serving cell and the at least one adjacent cell, the updated CSP to an adjacent BS; acquiring a CSP of at least one cell serviced by the adjacent BS; transmitting the updated CSP and the acquired CSP and a reference signal for estimating a channel to at least one user equipment (UE) of the serving cell; receiving, from the UE, at least one multi-cell channel quality indicator (CQI) as a feedback determined by the UE based on information on an inter-cell interference; and performing downlink scheduling operation based on the multi-cell CQI, wherein the CSP comprises information on subsets of a codebook and a corresponding relationship between each subset and each time and frequency resource, wherein each of the subsets is used to precode data that is transmitted through a time and frequency resource corresponding to each of the subset, wherein each of the codebooks comprises an empty set or a set of one or more precoding vectors, and wherein the inter-cell interference is identified by the UE using codebooks included in the CSP of each cell and information on channels acquired from the reference signal of each cell. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An apparatus for operating a base station (BS) in a multiple input multiple output (MIMO) system, the apparatus comprising:
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a processor configured to determine whether there is a cell having an updated CSP among a serving cell and at least one adjacent cell, each cell having the CSP being different from each other; a transceiver configured to; transmit the updated CSP to an adjacent BS next to the serving BS, if it is determined that there is a cell having the updated CSP among the serving cell and the at least one adjacent cell, receive a CSP of at least one cell serviced by the adjacent BS, transmit the updated CSP and the acquired CSP and a reference signal for estimating a channel to at least one user equipment (UE) of the serving cell, and receive, from the at least one UE, at least one multi-cell channel quality indicator (CQI) as a feedback determined by the UE based on information on an inter-cell interference, wherein the processor is further configured to perform downlink scheduling operation based on the multi-cell CQI, wherein the CSP comprises information on subsets of a codebook and a corresponding relationship between each subset and each time and frequency resource, wherein each of the subsets is used to precode data that is transmitted through a time and frequency resource corresponding to each of the subset, wherein each of the codebooks comprises an empty set or a set of one or more precoding vectors, and wherein the inter-cell interference is identified by the UE using codebooks included in the CSP of each cell and information on channels acquired from the reference signal of each cell. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method for operating a user equipment (UE) in a multiple input multiple output (MIMO) system, the method comprising:
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receiving a codebook subset pattern (CSP) of each of a plurality of cells from a serving base station (BS); receiving a reference signal for estimating a channel from each plurality of cells; determining a multi-cell channel quality indicator (CQI) based on an inter-cell interference that is identified by using codebooks included in the received CSP and information on channels acquired from the reference signal of each plurality of cells; transmitting the determined multi-cell CQI to the serving base station as a feedback; and receiving data, from the serving BS, according to the downlink scheduling performed by the serving BS based on the multi-cell CQI, wherein each plurality of cells has the CSP being different from each other, wherein the CSP comprises information on subsets of a codebook and a corresponding relationship between each subset and each time and frequency resource, wherein each of the subsets is used to precode data that is transmitted through a time and frequency resource corresponding to each of the subset, and wherein each of the codebooks comprises an empty set or a set of one or more precoding vectors.
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22. An apparatus for operating a user equipment (UE) in a multiple input multiple output (MIMO) system, the apparatus comprising:
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a transceiver configured to receive a codebook subset pattern (CSP) of each of a plurality of cells from a serving base station (BS) and to receive a reference signal for estimating a channel from each plurality of cells; and a processor configured to determine a multi-cell channel quality indicator (CQI) based on an inter-cell interference that is identified by using codebooks included in the received CSP and information on channels acquired from the reference signal of each plurality of cells, wherein the transceiver is further configured to transmit the determined multi-cell CQI as a feedback to the serving base station, and receive data, from the serving BS, according to the downlink scheduling performed by the serving BS based on the multi-cell CQI, wherein each of the plurality of cells has the CSP being different from each other, wherein the CSP comprises information on subsets of a codebook and a corresponding relationship between each subset and each time and frequency resource, wherein each of the subsets is used to precode data that is transmitted through a time and frequency resource corresponding to each of the subset, and wherein each of the codebooks comprises an empty set or a set of one or more precoding vectors.
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Specification