WO2011105213A1 - プリコーディングウェイト生成方法及び制御装置 - Google Patents
プリコーディングウェイト生成方法及び制御装置 Download PDFInfo
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- WO2011105213A1 WO2011105213A1 PCT/JP2011/052700 JP2011052700W WO2011105213A1 WO 2011105213 A1 WO2011105213 A1 WO 2011105213A1 JP 2011052700 W JP2011052700 W JP 2011052700W WO 2011105213 A1 WO2011105213 A1 WO 2011105213A1
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- mobile station
- station apparatus
- base station
- precoding
- precoding weight
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
- H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
- H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
- H04B7/0619—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal using feedback from receiving side
- H04B7/0621—Feedback content
- H04B7/0626—Channel coefficients, e.g. channel state information [CSI]
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/022—Site diversity; Macro-diversity
- H04B7/024—Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/0413—MIMO systems
- H04B7/0452—Multi-user MIMO systems
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
- H04B7/0697—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using spatial multiplexing
Definitions
- the present invention relates to a precoding weight generation method and control apparatus, and more particularly to a precoding weight generation method and control apparatus corresponding to multi-antenna transmission.
- UMTS Universal Mobile Telecommunications System
- WSDPA High Speed Downlink Packet Access
- HSUPA High Speed Uplink Packet Access
- CDMA Wideband Code Division Multiple Access
- the third generation system can achieve a maximum transmission rate of about 2 Mbps on the downlink using generally a fixed bandwidth of 5 MHz.
- a maximum transmission rate of about 300 Mbps on the downlink and about 75 Mbps on the uplink can be realized using a variable band of 1.4 MHz to 20 MHz.
- LTE-A LTE Advanced
- LTE-A LTE Advanced
- a MIMO (Multi Input Multi Output) system has been proposed as a wireless communication technology that improves data rate (frequency utilization efficiency) by transmitting and receiving data with multiple antennas (for example, Non-patent document 1).
- MIMO system a plurality of transmission / reception antennas are prepared in a transmitter / receiver, and different transmission information sequences are transmitted simultaneously from different transmission antennas of a transmitter (for example, base station apparatus eNB).
- a transmitter for example, base station apparatus eNB
- the receiver for example, mobile station apparatus UE
- the data rate (Frequency utilization efficiency) can be increased.
- transmission information sequences transmitted simultaneously from different transmission antennas are all transmitted from a single user MIMO (SU-MIMO (Single User MIMO)), which is the same user, and multi-users are transmitted from different users.
- SU-MIMO Single User MIMO
- MU-MIMO Multi-User MIMO
- LTE-A system In the LTE-A system (LTE-A system), transmission / reception of data channel signals by Coordinated Multiple Point (CoMP) is studied for the purpose of reducing inter-cell interference or improving received signal strength. Has been. By performing transmission / reception by CoMP, it is expected that the system characteristics of the mobile station apparatus UE located at the cell edge will be improved.
- CSI Channel State Information
- JT Joint Transmission
- PDSCH Physical Downlink Shared Channel
- the base station apparatus eNB that generates the precoding weight can accurately grasp CSI information from all the mobile station apparatuses UE for all the coordinated base station apparatuses eNB, It becomes possible to improve the system characteristics for all the mobile station apparatuses UE including the mobile station apparatus UE located at the end to the maximum. However, a situation may occur in which CSI information is not fed back from all mobile station apparatuses UE due to a reduction in the amount of feedback information in the mobile station apparatus UE or the like.
- the present invention has been made in view of such circumstances, and even when CSI information is not fed back from all mobile station apparatuses in an environment where joint transmission is performed for a plurality of mobile station apparatuses, the mobile station It is an object of the present invention to provide a precoding weight generation method and a control device that can reduce interference between devices as much as possible.
- the precoding weight generation method of the present invention is a precoding weight generation method used when a plurality of base station apparatuses cooperate with each other to transmit data to a plurality of mobile station apparatuses using a joint transmission. Generating a channel matrix having, as matrix components, channel state information fed back from a plurality of mobile station devices spatially multiplexed for each cell managed by the mobile station device, and feeding back the channel state information based on the channel matrix Generating a precoding weight sequentially from a cell having a large amount of data, and transmitting data to a first mobile station apparatus that feeds back channel state information to a cell other than a weight generation target cell that is a generation target of a precoding weight When targeting, the weight generation pair For the third mobile station apparatus that does not suppress interference to the second mobile station apparatus that feeds back channel state information other than the cell, but does not feed back the channel state information other than the weight generation target cell A precoding weight for suppressing interference is generated.
- a precoding weight for suppressing interference is generated for the third mobile station apparatus that does not feed back channel state information other than the weight generation target cell, cells other than the weight generation target cell are generated.
- CSI information is not fed back from all mobile station devices in an environment where joint transmission is performed for a plurality of mobile station devices, it is possible to reduce interference between the mobile station devices as much as possible.
- interference with the third mobile station apparatus that does not feed back channel state information other than the weight generation target cell is preferential to the second mobile station apparatus that feeds back channel state information other than the weight generation target cell. Therefore, interference between mobile station devices can be suppressed regardless of the number of cooperative cells, since it can be efficiently used for interference suppression in consideration of the degree of freedom of antennas in the base station device. Is possible.
- the precoding weight generation method of the present invention is a precoding weight generation method used when a plurality of base station apparatuses cooperate with each other to transmit data to a plurality of mobile station apparatuses using a joint transmission.
- the matrix component includes channel state information fed back from a plurality of mobile station apparatuses spatially multiplexed in each cell, and a matrix corresponding to channel state information between the mobile station apparatus and the base station apparatus that are not fed back.
- the method includes a step of generating a channel matrix having zero components, and a step of collectively generating precoding weights for all mobile station apparatuses based on the channel matrix.
- channel state information fed back from a plurality of mobile station devices is included in the matrix component, and a matrix component corresponding to channel state information between the mobile station device and the base station device that is not fed back is set to 0 component. Since the precoding weight is generated based on the channel matrix, it is possible to generate the precoding weight including the mobile station apparatus to which the channel state information is not fed back, and the interference to the mobile station apparatus to which the channel state information is fed back. Since it can be effectively suppressed, even when CSI information is not fed back from all mobile station devices in an environment where joint transmission is performed for a plurality of mobile station devices, interference between mobile station devices is reduced as much as possible. It becomes possible to do.
- a plurality of base station apparatuses can form a transmission beam capable of suppressing interference.
- a mobile station apparatus having a larger number of cells (feeding back information) can suppress interference between other mobile station apparatuses.
- a precoding weight that suppresses interference is generated for a mobile station apparatus that does not feed back channel state information other than the weight generation target cell, interference is prevented in cells other than the weight generation target cell. Since it is possible to preferentially suppress interference to mobile station devices that cannot be expected to be suppressed, it is possible to effectively improve system characteristics in a mobile station device with a small number of cells that feed back channel state information. Even when CSI information is not fed back from all mobile station apparatuses in an environment where joint transmission is performed, it is possible to reduce interference between the mobile station apparatuses as much as possible.
- FIG. 1 is a network configuration diagram for explaining an outline of a joint transmission which is one of CoMPs.
- the base station apparatus eNB # 1 and the base station apparatus eNB # 2 cooperate, and the same mobile station apparatus UE # 1 to UE # 4 from these base station apparatuses eNB # 1 and # 2
- FIG. 2 shows a case where a joint transmission for combining and transmitting a data channel signal (PDSCH) is performed.
- PDSCH data channel signal
- H 11 indicates channel state information (hereinafter referred to as “CSI (Channel State Information) information”) of a transmission channel from one base station apparatus eNB # 1 to the mobile station apparatus UE # 1.
- H 21 indicates CSI information of the transmission channel from the other base station apparatus eNB # 2 to the mobile station apparatus UE # 1.
- the mobile station apparatuses UE # 1 to # 4 measure the CSI information of these transmission path channels and feed back to the base station apparatuses eNB # 1 and # 2.
- the CSI information fed back to the base station apparatuses eNB # 1 and # 2 is collected in a base station apparatus eNB # 1 (hereinafter referred to as “control base station apparatus eNB” as appropriate) that generates precoding weights necessary for joint transmission. It is done. Then, in the control base station apparatus eNB, precoding weights of data channel signals for the mobile station apparatuses UE # 1 to # 4 are generated from the base station apparatuses eNB # 1 and # 2. By using these precoding weights, the base station apparatuses eNB # 1 and # 2 perform precoding of data channel signals for the mobile station apparatuses UE # 1 to # 4, so that the mobile station apparatuses UE # 1 to # 4 Improvement of system characteristics is expected.
- the control base station apparatus eNB transmits CSI information from the mobile station apparatuses UE # 1 to # 4 to the base station apparatuses eNB # 1 and eNB # 2. It is premised on accurately grasping.
- the ratio between the received power of a signal arriving from a certain base station apparatus eNB and the received power at the base station apparatus where the received power is maximum It is common to feed back CSI information only when the threshold is exceeded. Therefore, when the mobile station apparatus UE is located at a long distance from the base station apparatus eNB and the reception power ratio of the signal from the base station apparatus eNB is equal to or less than a predetermined threshold, the situation where the CSI information is not fed back. Can occur. In FIG.
- the received power of the signal from base station apparatus eNB # 2 is below a predetermined threshold value, and the case where CSI information is not fed back is shown. That is, in FIG. 1, the CSI information is fed back from the mobile station apparatuses UE # 1 and # 2 to the base station apparatuses eNB # 1 and # 2, whereas the base station apparatus is transmitted from the mobile station apparatuses UE # 3 and # 4. The case where CSI information is fed back only to eNB # 1 is shown.
- the control base station device eNB performs appropriate pre-processing. Coding weights cannot be generated, and it becomes difficult to improve the system characteristics of the mobile station apparatuses UE # 1 to UE # 4 to the maximum.
- the CSI information from all the mobile station apparatuses UE for all the base station apparatuses eNB that cooperate with each other is assumed to be accurate, all the mobile stations Focusing on the fact that CSI information is not fed back from the device UE, the present invention has been achieved.
- the precoding weight necessary for the joint transmission is generated in one base station apparatus eNB # 1 .
- the configuration for generating the precoding weight is limited to this. Is not to be done. For example, it may be performed by the other base station apparatus eNB # 2, or may be performed by an upper station apparatus connected to these base station apparatuses eNB # 1 and # 2.
- the base station apparatus eNB or higher station apparatus that generates the precoding weight necessary for the joint transmission in this way can be called a control apparatus.
- a channel matrix H K (with matrix components of CSI information of a plurality of mobile station apparatuses UE that are spatially multiplexed for each cooperative cell (base station apparatus eNB). “K” indicates a cell number), and based on this channel matrix H K , precoding weights are sequentially generated from a cell having a large number of mobile station apparatuses UE that feed back CSI information.
- weight generation target cell the cell for which the precoding weight is generated.
- a precoding weight that does not suppress interference is generated for the mobile station apparatus UE that feeds back CSI information.
- the precoding weight generation method in the cells # 1 and # 2 is described here, the precoding weight is generated in the same manner even when there are three or more cooperating cells. .
- the precoding weight is generated in the same manner even when there are three or more cooperating cells. .
- the precoding weight generation method will be described using a specific example shown in FIG.
- CSI information is fed back from the mobile station apparatuses UE # 1 to # 4 to the base station apparatus eNB # 1, and the mobile station apparatuses UE # 1 and # 4 are transmitted to the base station apparatus eNB # 2. Since the CSI information is fed back from 2, the cell in which the base station apparatus eNB # 1 is installed corresponds to the cell # 1, and the cell in which the base station apparatus eNB # 2 is installed corresponds to the cell # 2.
- precoding weights that do not suppress interference are generated for the other mobile station apparatuses UE # 1 and # 2.
- the CSI information is fed back to the cells other than the cells # 1 and # 2 after removing the mobile station apparatuses UE # 3 and # 4 that have already suppressed interference.
- the other mobile station apparatuses UE (not present in FIG.
- precoding weight that does not suppress interference is generated.
- precoding weights for mobile station apparatuses UE # 1 and # 2 in cell # 2 refer to precoding weights for mobile station apparatuses UE # 1 and # 2 generated in cell # 1. Is done.
- a precoding weight generation formula in the precoding weight generation method according to the first aspect will be shown.
- the precoding weight generation formula according to the first aspect will be described using the specific example shown in FIG.
- generation formula using ZF (Zero Forcing) precoding method is shown here, it is not limited to this.
- Equation 1 a channel matrix shown in (Equation 1) configured by CSI information of all the mobile station apparatuses UE # 1 to # 4 spatially multiplexed in the cell # 1 H eNB1 is generated. Then, based on this channel matrix HeNB1 , precoding weights for mobile station apparatuses UE # 1 to UE # 4 are individually generated. (Formula 1)
- Precoding weight w eNB1, UE1 for the mobile station apparatus UE # 1 is a submatrix of the channel matrix H eNB1, using the channel matrix H 'eNB1 shown in (Equation 2) is calculated by (Equation 3).
- the channel matrix H ′ eNB1 is configured from CSI information (h 11 , h 13 , h 14 ) of the mobile station apparatuses UE # 1, # 3, and # 4 excluding the mobile station apparatus UE # 2. That is, the channel matrix H ′ eNB1 configures a channel matrix in which the matrix component for the mobile station apparatus UE # 2 is deleted.
- (Formula 2) (Formula 3)
- the fact that CSI information is included in the channel matrix H ′ eNB1 means that an appropriate transmission beam can be formed in the corresponding mobile station apparatus UE with reference to the CSI information. That is, it is possible to form a transmission beam having directivity at the target terminal for data transmission, while forming a transmission beam with null directed at the non-target terminal for data transmission.
- the mobile station apparatus UE # 2 that feeds back CSI information in addition to the weight generation target cell is excluded from the target for forming a transmission beam directed to null. Therefore, the degree of freedom of antenna selection in the base station apparatus eNB is ensured.
- precoding weights w ′ eNB1 and UE3 and w ′ eNB1 and UE4 for mobile station apparatuses UE # 3 and # 4 are also generated, but these values are not used.
- precoding weights w eNB1 and UE3 and w eNB1 and UE4 for the mobile station apparatuses UE # 3 and # 4 values generated according to (Equation 6) described later are used.
- the precoding weight w eNB1, UE2 for the mobile station apparatus UE # 2 is a submatrix of the channel matrix H eNB1, using a channel matrix H'' eNB1 shown in (Equation 4) and (Equation 5) Calculated.
- the channel matrix H ′′ eNB1 is configured from CSI information (h 12 , h 13 , h 14 ) of the mobile station apparatuses UE # 2, # 3, and # 4 excluding the mobile station apparatus UE # 1. (Formula 4) (Formula 5)
- precoding weights w ′′ eNB1, UE3 , w ′′ eNB1, UE4 for the mobile station apparatuses UE # 3 and # 4 are also generated. As in the above (Formula 3), These values are not used.
- precoding weights w eNB1 and UE3 and w eNB1 and UE4 for the mobile station apparatuses UE # 3 and # 4 values generated according to (Equation 6) described later are used.
- Precoding weights w eNB1, UE3 , w eNB1 and UE4 for mobile station apparatuses UE # 3 and # 4 are calculated by (Equation 6) using channel matrix HeNB1 .
- (Formula 6) In this case, unlike the above (formula 1) and (formula 3), the CSI information (h 11 , h 12 , h 13 , h 14 ) of all the mobile station apparatuses UE # 1 to # 4 is included in the data This is to form a transmission beam in which nulls are directed to all the mobile station apparatuses UE # 1 to # 4 other than the mobile station apparatus UE to be transmitted.
- precoding weights w ′ eNB1 and UE1 and w ′ eNB1 and UE2 for mobile station apparatuses UE # 1 and # 2 are also generated, but these values are not used.
- precoding weights w eNB1 and UE1 and w eNB1 and UE2 for the mobile station apparatuses UE # 1 and # 2 values generated according to the above (formula 3) and (formula 5) are used.
- the precoding weight in cell # 2 is generated.
- H eNB2 is generated.
- the precoding weight with respect to mobile station apparatus UE # 1 and # 2 is produced
- precoding weights for generating a transmission beam directed to the null are generated for the mobile station apparatus UE # 2.
- the reason why the transmission beam directed to the null is formed for the mobile station apparatus UE # 2 is that the mobile station apparatus UE # 2 is removed from the target for forming the transmission beam directed to the null in the cell # 1. This is because the interference between the other mobile station apparatuses UE is not reduced for the station apparatus UE # 2.
- the precoding weights w eNB1 and UE1 generated in the cell # 1 and the CSI information h 12 and h 22 of the mobile station apparatus UE # 2 are considered.
- the amount of interference given to the mobile station apparatus UE # 2 by the transmission beam pattern of the mobile station apparatus UE # 1 is calculated by (Equation 8).
- precoding weights w eNB2 and UE1 for mobile station apparatus UE # 1 are calculated by (Equation 9). Thereby, the influence of the interference by the precoding weight with respect to mobile station apparatus UE # 2 produced
- precoding weights w eNB2 and UE2 for mobile station apparatus UE # 2 when generating precoding weights w eNB2 and UE2 for mobile station apparatus UE # 2, precoding weights for generating a transmission beam directed to null are generated for mobile station apparatus UE # 1.
- the precoding weights w eNB1 and UE2 generated in the cell # 1 and the CSI information h 11 and h 21 of the mobile station apparatus UE # 1 are considered.
- the amount of interference given to the mobile station apparatus UE # 1 by the transmission beam pattern of the mobile station apparatus UE # 2 is calculated by (Equation 10).
- precoding weights w eNB2 and UE2 for mobile station apparatus UE # 2 are calculated by (Equation 11). Thereby, the influence of the interference by the precoding weight with respect to mobile station apparatus UE # 1 produced
- the base station apparatus eNB2 to the mobile station apparatuses UE # 1 and # 2
- a transmission beam in which null is not directed to the mobile station apparatuses UE # 3 and # 4 is formed, and
- the station apparatuses UE # 3 and # 4 are affected by interference between the mobile station apparatuses UE.
- FIG. 2 is a diagram for explaining a state of a transmission beam when data is transmitted to mobile station apparatus UE # 1 using a precoding weight generated by the precoding weight generation method according to the first aspect.
- the state of the transmission beam from the base station apparatus eNB to the mobile station apparatus UE is indicated by a thick solid line, a thin solid line, and a one-dot chain line arrow.
- a thick solid line indicates a transmission beam having directivity
- a thin solid line indicates a transmission beam to which null is not directed
- an alternate long and short dash line indicates a transmission beam to which null is directed.
- a transmission beam having directivity is formed from the base station apparatus eNB # 1 with respect to the mobile station apparatus UE # 1 that is a target of data transmission.
- a transmission beam directed to null is formed.
- interference between other mobile station apparatuses UE is suppressed.
- a transmission beam to which null is not directed is formed, and interference between other mobile station apparatuses UE is not suppressed.
- a transmission beam having directivity is formed from the base station apparatus eNB # 2 with respect to the mobile station apparatus UE # 1 that is a target of data transmission.
- the mobile station apparatus UE # 2 whose interference is not suppressed by the base station apparatus eNB # 1
- a transmission beam directed to null is formed, and the interference is suppressed.
- mobile station apparatuses UE # 3 and # 4 a transmission beam to which null is not directed is formed, and interference is not suppressed.
- the mobile station apparatus UE # 1 constitutes the first mobile station apparatus in the claims
- the mobile station apparatus UE # 2 constitutes the second mobile station apparatus
- the mobile station apparatus UE # 3, # 4 constitutes a third mobile station apparatus.
- FIG. 3 is a diagram for explaining a state of a transmission beam when data is transmitted to the mobile station apparatus UE # 4 using the precoding weight generated by the precoding weight generation method according to the first aspect.
- a transmission beam having directivity is formed from the base station apparatus eNB # 1 with respect to the mobile station apparatus UE # 4 that is a target of data transmission.
- a transmission beam to which null is directed is formed, and interference between other mobile station apparatuses UE is suppressed.
- data is not transmitted from the base station apparatus eNB # 2 to the mobile station apparatus UE # 4 that is a target of data transmission (indicated by a dotted arrow in FIG. 3).
- a channel matrix H K composed of CSI information of a plurality of mobile station apparatuses UE spatially multiplexed for each cooperative cell is generated, and this channel matrix H Based on K , precoding weights are sequentially generated from cells having a large number of mobile station apparatuses UE that feed back CSI information.
- interference with the mobile station apparatus UE that cannot be expected to suppress interference in cells other than the weight generation target cell can be preferentially suppressed, so that the system characteristics in the mobile station apparatus UE with a small number of cells to which CSI information is fed back Can be effectively improved, and even when CSI information is not fed back from all the mobile station apparatuses UE in an environment where joint transmission is performed for a plurality of mobile station apparatuses UE, interference between the mobile station apparatuses UE is reduced as much as possible. It becomes possible to do.
- the precoding weight generation method in the precoding weight generation method according to the first aspect, it can be efficiently used for interference suppression in consideration of the degree of freedom of the antenna in the base station apparatus eNB. It becomes possible to suppress interference between the mobile station apparatuses UE.
- the matrix component includes CSI information of a plurality of cooperating cells (base station apparatus eNB) and a plurality of mobile station apparatuses UE spatially multiplexed by MU-MIMO.
- a channel matrix H having a matrix component corresponding to CSI information between the mobile station apparatus UE and the base station apparatus eNB that are not fed back as zero components is generated, and all the mobile station apparatuses UE are generated based on the channel matrix H.
- Precoding weights from all base station apparatuses eNB are generated collectively.
- a precoding weight generation formula in the precoding weight generation method according to the second aspect will be shown.
- the precoding weight generation formula according to the second aspect will be described using the specific example shown in FIG.
- generation formula using ZF (Zero Forcing) precoding method is shown here, it is not limited to this.
- the precoding weight is generated by the precoding weight generation method according to the second aspect, first, the CSI of all mobile station apparatuses UE # 1 to # 4 that are spatially multiplexed in all cells # 1 and # 2 A channel matrix H shown in (Equation 12) composed of information is generated. In this case, a value of “0” is inserted into the matrix component corresponding to the CSI information between the mobile station apparatuses UE # 3 and # 4 and the base station apparatus eNB # 2 where CSI information is not fed back. (Formula 12)
- FIG. 4 is a diagram for explaining a state of a transmission beam when data is transmitted to the mobile station apparatus UE # 1 using the precoding weight generated by the precoding weight generation method according to the second aspect.
- the state of the transmission beam from the base station apparatus eNB to the mobile station apparatus UE is indicated by thick solid lines, thin solid lines, and dashed lines.
- a thick solid line indicates a transmission beam having directivity
- a thin solid line indicates a transmission beam to which null is not directed
- an alternate long and short dash line indicates a transmission beam to which null is directed.
- a transmission beam having directivity is formed from the base station apparatus eNB # 1 with respect to the mobile station apparatus UE # 1 that is a target of data transmission. Also, for mobile station apparatuses UE # 2 to # 4, a transmission beam to which null is directed is formed, and interference between other mobile station apparatuses UE is suppressed.
- a transmission beam having directivity is formed from the base station apparatus eNB # 2 with respect to the mobile station apparatus UE # 1 that is a target of data transmission. Also, for the mobile station apparatus UE # 2, a transmission beam to which a null is directed is formed, and interference is suppressed. On the other hand, for mobile station apparatuses UE # 3 and # 4, a transmission beam to which null is not directed is formed, and interference is not suppressed.
- FIG. 5 is a diagram for explaining a state of a transmission beam when data is transmitted to the mobile station apparatus UE # 4 using the precoding weight generated by the precoding weight generation method according to the second aspect.
- a transmission beam having directivity is formed from the base station apparatus eNB # 1 with respect to the mobile station apparatus UE # 4 that is a target of data transmission.
- a transmission beam to which null is directed is formed, and interference between other mobile station apparatuses UE is suppressed.
- data is not transmitted from the base station apparatus eNB # 2 to the mobile station apparatus UE # 4 that is a target of data transmission (indicated by a dotted arrow in FIG. 5).
- the mobile station apparatus UE and the base station including the CSI information of all the mobile station apparatuses UE # 1 to # 4 that are spatially multiplexed in all cells and not fed back
- a channel matrix H having a matrix component corresponding to CSI information with the station apparatus eNB as 0 component is generated, and based on the channel matrix H, pre-transmission from all base station apparatuses eNB for all mobile station apparatuses UE Generate coding weights collectively. Accordingly, it is possible to generate precoding weights including the mobile station apparatus UE to which CSI information is not fed back, and to effectively suppress interference with the mobile station apparatus UE to which CSI information is fed back. Even when CSI information is not fed back from all the mobile station apparatuses UE in an environment where joint transmission is performed for the mobile station apparatus UE, it is possible to reduce interference between the mobile station apparatuses UE as much as possible.
- a plurality of base station apparatuses eNB Since a transmission beam capable of suppressing interference can be formed by the mobile station apparatus UE having a larger number of cooperating cells, interference between other mobile station apparatuses UE can be suppressed.
- FIG. 6 is a diagram for explaining a configuration of the mobile communication system 1 including the mobile station apparatus 10 and the base station apparatus 20 according to the embodiment of the present invention.
- the mobile communication system 1 shown in FIG. 6 is a system including, for example, an LTE system or SUPER 3G.
- the mobile communication system 1 may be called IMT-Advanced or 4G.
- the mobile communication system 1 includes a base station device 20 and a plurality of mobile station devices 10 (10 1 , 10 2 , 10 3 ,... 10 n , n communicating with the base station device 20. Is an integer of n> 0).
- the base station apparatus 20 is connected to the higher station apparatus 30, and the higher station apparatus 30 is connected to the core network 40.
- the mobile station device 10 communicates with the base station device 20 in the cell 50.
- the upper station apparatus 30 includes, for example, an access gateway apparatus, a radio network controller (RNC), a mobility management entity (MME), and the like, but is not limited thereto.
- RNC radio network controller
- MME mobility management entity
- each mobile station apparatus (10 1 , 10 2 , 10 3 ,... 10 n ) has the same configuration, function, and state, the following description will be given as the mobile station apparatus 10 unless otherwise noted. Proceed. For convenience of explanation, it is assumed that the mobile station device 10 is in radio communication with the base station device 20, but more generally, user equipment (UE: User Equipment) including both a mobile terminal device and a fixed terminal device. It's okay.
- UE User Equipment
- OFDMA Orthogonal Frequency Division Multiple Access
- SC-FDMA Single Carrier Frequency Division Multiple Access
- OFDMA is a multi-carrier transmission scheme that performs communication by dividing a frequency band into a plurality of narrow frequency bands (subcarriers) and mapping data to each subcarrier.
- SC-FDMA is a single carrier transmission method that reduces interference between terminals by dividing a system band into bands each consisting of one or continuous resource blocks for each terminal, and a plurality of terminals using different bands. .
- PDSCH shared by each mobile station device 10 and downlink L1 / L2 control channels (PDCCH, PCFICH, PHICH) are used.
- User data that is, a normal data signal is transmitted by this PDSCH. Transmission data is included in this user data. Note that the CC and scheduling information assigned to the mobile station device 10 by the base station device 20 are notified to the mobile station device 10 through the L1 / L2 control channel.
- PUSCH Physical Uplink Shared Channel
- PUCCH Physical Uplink Control Channel
- User data is transmitted by this PUSCH.
- CSI information, downlink radio quality information (CQI: Channel Quality Indicator), etc. are transmitted by PUCCH.
- the precoding weight generation method according to the present invention mainly relates to processing of the base station apparatus 20 included in such a mobile communication system 1. Since the mobile station apparatus 10 has a normal function of measuring channel state information of a transmission channel with the base station apparatus 20 and feeding back the measurement result as CSI information, detailed description thereof is omitted. To do.
- FIG. 7 is a block diagram showing a configuration of a transmission unit of base station apparatus 20 according to the present embodiment.
- the transmission part of the two base station apparatuses 20 (20A, 20B) which cooperate is shown for convenience of explanation.
- the base station apparatus 20A described in the upper part constitutes a control base station apparatus that generates precoding weights
- the base station apparatus 20B described in the lower part is pre-configured from the control base station apparatus.
- a base station apparatus (controlled base station apparatus) that receives the coding weight is configured.
- the base station device 20A is associated with the base station device eNB # 1 illustrated in FIG. 1, and the base station device 20B is associated with the base station device eNB # 2 illustrated in FIG. That is, the base station apparatus 20A receives CSI information from the mobile station apparatuses UE # 1 to # 4, and the base station apparatus 20B receives CSI information only from the mobile station apparatuses UE # 1 and # 2.
- the base station device 20A constitutes a control base station device, and CSI information (CSI information from the mobile station devices UE # 1 and # 2) received by the base station device 20B is collected. ing.
- the words of mobile station apparatuses UE # 1 to UE # 4 are used in accordance with FIG.
- Transmission data # 1 to # 4 for mobile station apparatuses UE # 1 to # 4 instructed to be transmitted from a host station apparatus 30 are sent to channel coding sections 200 # 1 to 200 # 4.
- transmission data # 1 to # 4 are output to data modulation sections 201 # 1 to 201 # 4 and subjected to subcarrier modulation.
- Transmission data # 1 to # 4 subcarrier-modulated by data modulation sections 201 # 1 to 201 # 4 are precoded multiplication sections 202 # 1 to 202 # 4 and precoding multiplication sections 210 # 1 to 210 # 4. Is output.
- Precoding multiplication sections 202 # 1 to 202 # 4 transmit transmission data # 1 to # 4 for each of transmission antennas TX # 1 to TX # N based on a precoding weight given from precoding weight generation section 208 described later. Phase and / or amplitude shift (weighting of transmit antennas TX # 1 to TX # N by precoding). Transmission data # 1 to # 4 whose phases and / or amplitudes have been shifted by precoding multiplication sections 202 # 1 to 202 #k are output to multiplexer (MUX) 203.
- MUX multiplexer
- the transmission data # 1 to # 4 shifted in phase and / or amplitude are combined to generate transmission signals for the transmission antennas TX # 1 to TX # N.
- the transmission signal generated by the multiplexer (MUX) 203 is subjected to inverse fast Fourier transform in inverse fast Fourier transform units (IFFT) 204 # 1 to 204 # N, and converted from a frequency domain signal to a time domain signal.
- IFFT inverse fast Fourier transform units
- CP cyclic prefix
- the transmission antennas TX # 1 to TX # are transmitted via the duplexers 207 # 1 to 207 # N. N, and transmitted from the transmission antennas TX # 1 to TX # N to the mobile station apparatuses UE # 1 to UE # 4 on the downlink.
- precoding multipliers 210 # 1 to 210 # 4 transmit data # 1 to ## for each of transmission antennas TX # 1 to TX # M based on a precoding weight given from precoding weight generator 208, which will be described later. 4 is phase and / or amplitude shifted (weighting of transmit antennas TX # 1 to TX # M by precoding). Transmission data # 1 to # 4 whose phases and / or amplitudes have been shifted by precoding multipliers 210 # 1 to 210 # 4 are output to multiplexer (MUX) 211.
- MUX multiplexer
- the transmission data # 1 to # 4 shifted in phase and / or amplitude are combined to generate a transmission signal for each of the transmission antennas TX # 1 to TX # M.
- the transmission signal generated by the multiplexer (MUX) 211 is subjected to inverse fast Fourier transform by the inverse fast Fourier transform units (IFFT) 212 # 1 to 212 # M to be converted from the frequency domain signal to the time domain signal.
- IFFT inverse fast Fourier transform units
- CP cyclic prefix
- the transmission antennas TX # 1 to TX # are transmitted via the duplexers 215 # 1 to 215 # M.
- M is transmitted to the mobile station apparatuses UE # 1 to UE # 4 via downlink from the transmission antennas TX # 1 to TX # M.
- the precoding weight generation unit 208 includes CSI information (UE # 1-eNB # 1 CSI shown in FIG. 7) between the base station apparatus 20A (eNB # 1) measured by the mobile station apparatuses UE # 1 to UE # 4.
- CSI information (such as “UE # 1-eNB # 2 CSI information” shown in FIG. 7) between the base station apparatus 20B (eNB # 2) measured by the mobile station apparatuses UE # 1 and # 2 ) And.
- Precoding weight generating unit 208 according to the precoding weight generating method according to the first or second aspect described above, it generates a channel matrix H K or channel matrix H having these CSI information to matrix components, these channels based on the matrix H K or channel matrix H, to generate precoding weights to the mobile station apparatus UE # 1 ⁇ # 4. That is, the precoding weight generation unit 208 constitutes a matrix generation unit and a weight generation unit in the claims.
- precoding weight generating method when following precoding weight generating method according to the first embodiment generates a composed channel matrix H K in CSI information of a plurality of mobile stations UE to spatial multiplexing for each cell to be coordinated, the channel matrix based on H K, sequentially generate precoding weights from the cell number of the mobile station apparatus UE is often fed back CSI information.
- interference with the mobile station apparatus UE that cannot be expected to suppress interference in cells other than the weight generation target cell can be preferentially suppressed, so that the system characteristics in the mobile station apparatus UE with a small number of cells to which CSI information is fed back Can be effectively improved, and even when CSI information is not fed back from all the mobile station apparatuses UE in an environment where joint transmission is performed for a plurality of mobile station apparatuses UE, interference between the mobile station apparatuses UE is reduced as much as possible. It becomes possible to do.
- the precoding weight generation method according to the first aspect when the precoding weight generation method according to the first aspect is followed, it can be efficiently used for interference suppression in consideration of the degree of freedom of the antenna in the base station apparatus eNB. Therefore, it becomes possible to suppress interference between the mobile station apparatuses UE.
- the mobile station apparatus UE including CSI information of all mobile station apparatuses UE # 1 to # 4 spatially multiplexed in all cells and not fed back
- a channel matrix H having a matrix component corresponding to CSI information with the base station apparatus eNB as 0 component is generated, and based on this channel matrix H, from all base station apparatuses eNB for all mobile station apparatuses UE Precoding weights are generated collectively. Accordingly, it is possible to generate precoding weights including the mobile station apparatus UE to which CSI information is not fed back, and to effectively suppress interference with the mobile station apparatus UE to which CSI information is fed back. Even when CSI information is not fed back from all the mobile station apparatuses UE in an environment where joint transmission is performed for the mobile station apparatus UE, it is possible to reduce interference between the mobile station apparatuses UE as much as possible.
- the mobile station apparatus UE that feeds back CSI information to a plurality of cooperating cells (base station apparatus eNB), a plurality of base stations Since it is possible to form a transmission beam capable of suppressing interference in the device eNB, it is possible to suppress interference between other mobile station devices UE as the number of coordinated cells increases.
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Abstract
Description
(式1)
(式2)
(式3)
(式4)
(式5)
(式6)
この場合において、上記(式1)、(式3)と異なり、全ての移動局装置UE#1~#4のCSI情報(h11、h12、h13、h14)を含めるのは、データ送信対象となる移動局装置UE以外の全ての移動局装置UE#1~#4に対してヌルを向けた送信ビームを形成するためである。
(式7)
(式8)
(式9)
(式10)
(式11)
(式12)
Claims (6)
- 複数の基地局装置が協調してジョイントトランスミッションにより複数の移動局装置に対してデータ送信する際に用いられるプリコーディングウェイト生成方法であって、
各基地局装置が管理するセル毎に空間多重される複数の移動局装置からフィードバックされるチャネル状態情報を行列成分に有するチャネル行列を生成するステップと、当該チャネル行列に基づいてチャネル状態情報をフィードバックする移動局装置が多いセルから逐次的にプリコーディングウェイトを生成するステップとを具備し、
プリコーディングウェイトの生成対象となるウェイト生成対象セル以外にチャネル状態情報をフィードバックしている第1の移動局装置をデータ送信対象とする際、前記ウェイト生成対象セル以外にチャネル状態情報をフィードバックしている第2の移動局装置に対して干渉を抑圧しない一方、前記ウェイト生成対象セル以外にチャネル状態情報をフィードバックしていない第3の移動局装置に対して干渉を抑圧するプリコーディングウェイトを生成することを特徴とするプリコーディングウェイト生成方法。 - 前記第2の移動局装置に対応する行列成分を削除した前記チャネル行列を用いてプリコーディングウェイトを生成することを特徴とする請求項1記載のプリコーディングウェイト生成方法。
- 後続してプリコーディングウェイトが生成されるセルにおいて、先行して生成された前記第2の移動局装置に対するプリコーディングウェイトによる干渉の影響を弱めるプリコーディングウェイトを生成することを特徴とする請求項1又は請求項2記載のプリコーディングウェイト生成方法。
- 複数の基地局装置が協調してジョイントトランスミッションにより複数の移動局装置に対してデータ送信する際に用いられるプリコーディングウェイト生成方法であって、
各基地局装置が管理するセル及び各セルで空間多重される複数の移動局装置からフィードバックされるチャネル状態情報を行列成分に含み、フィードバックされない移動局装置と基地局装置との間のチャネル状態情報に対応する行列成分を0成分とするチャネル行列を生成するステップと、当該チャネル行列に基づいて全ての移動局装置に対するプリコーディングウェイトを一括的に生成するステップとを具備することを特徴とする請求項1記載のプリコーディングウェイト生成方法。 - 複数の基地局装置が協調してジョイントトランスミッションにより複数の移動局装置に対してデータ送信する際に用いられるプリコーディングウェイトを生成する制御装置であって、
各基地局装置が管理するセル毎に空間多重される複数の移動局装置からフィードバックされるチャネル状態情報を行列成分に有するチャネル行列を生成する行列生成手段と、当該チャネル行列に基づいてチャネル状態情報をフィードバックする移動局装置が多いセルから逐次的にプリコーディングウェイトを生成するウェイト生成手段とを具備し、
プリコーディングウェイトの生成対象となるウェイト生成対象セル以外にチャネル状態情報をフィードバックしている第1の移動局装置をデータ送信対象とする際、前記ウェイト生成対象セル以外にチャネル状態情報をフィードバックしている第2の移動局装置に対して干渉を抑圧しない一方、前記ウェイト生成対象セル以外にチャネル状態情報をフィードバックしていない第3の移動局装置に対して干渉を抑圧するプリコーディングウェイトを生成することを特徴とする制御装置。 - 複数の基地局装置が協調してジョイントトランスミッションにより複数の移動局装置に対してデータ送信する際に用いられる制御装置であって、
各基地局装置が管理するセル及び各セルで空間多重される複数の移動局装置からフィードバックされるチャネル状態情報を行列成分に含み、フィードバックされない移動局装置と基地局装置との間のチャネル状態情報に対応する行列成分を0成分とするチャネル行列を生成する行列生成手段と、当該チャネル行列に基づいて全ての移動局装置に対するプリコーディングウェイトを一括的に生成するウェイト生成手段とを具備することを特徴とする制御装置。
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US13/579,444 US8976882B2 (en) | 2010-02-24 | 2011-02-09 | Precoding weight generation method and control apparatus |
CN2011800110044A CN102771154A (zh) | 2010-02-24 | 2011-02-09 | 预编码权重生成方法以及控制装置 |
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WO2013097500A1 (zh) * | 2011-12-31 | 2013-07-04 | 电信科学技术研究院 | 一种传输信道状态信息的方法及装置 |
US20150288426A1 (en) * | 2012-11-06 | 2015-10-08 | Kyocera Corporation | Communication control method, base station, and processor |
CN108111209A (zh) * | 2012-09-07 | 2018-06-01 | 株式会社Ntt都科摩 | 无线通信方法、用户终端、无线基站以及无线通信系统 |
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CN104283594B (zh) * | 2013-07-03 | 2017-11-28 | 华为技术有限公司 | 一种预编码方法及设备 |
WO2016067318A1 (en) * | 2014-10-29 | 2016-05-06 | Nec Corporation | Communication system and method, base station, and user terminal |
US9979519B2 (en) | 2015-06-22 | 2018-05-22 | Trabus Technologies | Transmitting and receiving precoding weights |
JP6641937B2 (ja) * | 2015-12-01 | 2020-02-05 | 富士通株式会社 | 基地局、通信システム及び基地局の送信処理方法 |
WO2017166185A1 (zh) * | 2016-03-31 | 2017-10-05 | 华为技术有限公司 | 一种协调多用户间干扰的方法及基站 |
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