KR101701857B1 - A method and apparatus for transmitting precoding information for uplink transmission in multi base station mimo system - Google Patents

Abstract

The PMI combining ratio (PCR) used to generate the uplink precoding matrix W is transmitted to the UE by the base station. Using the PCR, a PMI that maximizes transmission performance and a PMI _Min that minimizes interference to neighboring base stations are combined into the uplink precoding matrix W. [ Since the PCR is provided by the base station, the overall operation of the system can be simplified, and the load of computation for generating the uplink precoding matrix W can be reduced at the terminal.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for transmitting precoding information for uplink transmission in a wireless communication system supporting multi-base station uplink MIMO, and a device for performing precoding in a multi-

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless communication system, and more particularly, to a method of transmitting precoding information for uplink transmission and a device performing the same in a wireless communication system supporting multiple base station uplink MIMO.

The following description relates to a method for transmitting and receiving feedback information in consideration of downlink channel conditions of a UE.

In a communication system, a receiving end transmits feedback information to a signal received from a transmitting end so as to perform efficient communication. Hereinafter, the feedback information transmitted in this manner will be briefly described as an example of a multi-antenna (MIMO) communication system.

FIG. 1 is a diagram schematically illustrating a structure of a transmitting and receiving end of a general multi-antenna communication system and information fed back from a receiving end.

First, the scheduler 101 of the receiving terminal 100 transmits information for allocating a transmission signal to an appropriate communication resource using reference signal information received from the transmitting terminal 200. The information includes information on a modulation and coding scheme (MCS) level, resources and precoding information. The transmitted signal is then transmitted over the channel via encoding and mapping 108, MIMO encoding 109 and OFDM modulation 110. On the other hand, the receiver 100 receives the transmitted signal and performs an inverse process of the transmitter. That is, the received signal is subjected to OFDM demodulation 102, MIMO decoding 103, and decoding and demapping 104 to obtain transmission information. The receiving terminal 100 performs channel estimation 105 using the OFDM demodulated signal and acquires feedback information 106 to feedback the estimated channel response to the transmitting terminal, 107 and is fed back to the transmitting terminal 200 through the scheduler 101 as shown in FIG.

Herein, the information fed back by the receiver 100 is divided into OFDM-related feedback information and MIMO-related feedback information.

Based on the measured channel quality information (CQI) and channel state information (e.g., SINR (Signal to Interference and Noise Ratio) or SNR (Signal to Noise Ratio)), And a Modulation and Coding Scheme (MCS) level.

In addition, the MIMO-OFDM system can be divided into an open loop (OL) method and a closed loop (CL) method.

Based on a code book based CL-MIMO (Codebook based CL-MIMO) based on a codebook, a base station estimates a PMI that is most suitable for a current channel situation. The modulation order and the coding rate have different values according to the estimated PMI. In general, the BS selects a PMI that maximizes the performance among the PMIs applied to the same channel, and information about the modulation and coding To a UE via a User Equipment (hereinafter, referred to as UE), and transmits the UE to the UE.

In addition, the MIMO system can determine the number of ranks that can be applied according to the channel conditions. For this purpose, the base station can inform the UE about how many ranks it is most effective to transmit in its current channel condition .

In addition, the MIMO system can operate as OL and CL as described above, and generally uses OL in a high speed condition and CL in a low speed condition. For this, the base station can select the mode of OL and CL and inform the UE.

When CL MIMO precoding is applied, two PMIs in time division duplex (TDD) or frequency division duplex (FDD) uplink transmission are combined to mitigate inter cell interference, Lt; RTI ID = 0.0 > precoding < / RTI >

In the uplink MIMO system, when performing single base station precoding in a multiple base station environment, it is a problem how to set up precoding in order to optimize the performance of the system.

Therefore, in order to solve the problems caused by the limitations and disadvantages of the related art, the present invention provides an apparatus and method for transmitting precoding information for uplink transmission in a wireless communication system supporting multi-base station uplink MIMO do.

The present invention provides an apparatus and method for transmitting precoding information for uplink transmission in a wireless communication system supporting multiple base station uplink MIMO.

Additional features and advantages of the invention will be set forth in part in the description that follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

According to an aspect of the present invention, there is provided a method for transmitting precoding information for uplink transmission in a wireless communication system supporting multiple input multiple output (MIMO) Determining a precoding matrix index (PMI) that maximizes transmission performance between the base station and the base station; Receiving a PMI _Min from the neighboring base station to minimize interference between the terminal and the neighboring base station; And a PMI combining ratio (PCR) used to combine the PMI and the PMI _Min to generate the uplink precoding matrix W and the PMI, the PMI _Min , and the precoding information transmission method / RTI >

According to another aspect of the present invention, in determining a precoding matrix for uplink transmission in a wireless communication system supporting multiple input multiple output (MIMO), a transmission performance between the UE and the serving base station (precoding matrix index) PMI that maximizes, PMI _Min above to minimize interference between the terminal and neighbor base station PMI and receiving the PMI combination ratio (PCR) is used to couple the PMI _Min from it said serving base station; And generating an uplink precoding matrix W using the PMI, the PMI _Min, and the PCR.

According to another aspect of the present invention, there is provided a terminal of a wireless communication system supporting multiple base station (BS) multiple input multiple output (MIMO), comprising: a precoding matrix index (PMI) terminal and the PMI and PMI _Min and receiving unit configured to receive the PMI combination ratio (PCR) is used to couple the PMI _Min from the serving base station to minimize the interference between neighboring base stations; And a processing unit configured to generate an uplink precoding matrix W using the PMI, the PMI _Min, and the PCR.

According to another aspect of the present invention, there is provided a base station in a wireless communication system supporting multiple input multiple output (MIMO), comprising: a base station configured to receive a PMI _Min that minimizes interference between a terminal and a neighboring base station, A receiving unit; A processing unit electrically connected to the receiving unit and configured to determine a precoding matrix index (PMI) that maximizes transmission performance between the terminal and the base station; And a PMI combining ratio used to combine the PMI and the PMI _Min to produce the PMI, the PMI _Min , and the uplink precoding matrix W under the control of the processing unit, (PCR) to the terminal.

In each aspect of the present invention, the PCR satisfies 0? PCR? 1.

In each aspect of the present invention, the PMI may be transmitted to the UE via a control information element, and the PMI _Min and the PCR may be transmitted to the UE through a Medium Access Control (MAC) message.

In each aspect of the present invention, the uplink precoding matrix W is expressed by the following equation

는 상기 PMI에 대응하는 프리코딩 행렬을 나타내고,

은 PMIMin에 대응하는 프리코딩 행렬을 나타낸다., ≪ / RTI > where < RTI ID =

Represents a precoding matrix corresponding to the PMI,

Represents a precoding matrix corresponding to PMIMin.

In each aspect of the present invention, the PMI is received via a control information element and the PMI and the PCR are received via a medium access control (MAC) message that minimizes the interference.

According to the present invention, in the determination of the uplink precoding matrix, since the operations in the serving base station and the terminal are simplified, the performance of the entire system can be improved.

The foregoing general description and the following detailed description of the present invention are provided by way of illustration only and are not intended to be limiting of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
FIG. 1 is a diagram schematically illustrating a structure of a transmitting and receiving end of a general multi-antenna communication system and information fed back from a receiving end.
2 is a flowchart illustrating a method of notifying a UE of PMI-related information in a multi-base station uplink MIMO from the position of a base station.
FIG. 3 is a flowchart illustrating a method for determining a precoding matrix applied to uplink transmission in a multi-base station uplink MIMO according to an embodiment of the present invention.
4 is a flowchart illustrating a method for transmitting PMI-related information to a UE in a multi-base station uplink MIMO according to an exemplary embodiment of the present invention, from the viewpoint of a serving BS.
5 is a flowchart illustrating a method of determining a precoding matrix applied to uplink transmission in a multi-base station uplink MIMO according to an exemplary embodiment of the present invention.
6 is a block diagram illustrating a configuration of a device applicable to a base station and a terminal and capable of performing the present invention.

Embodiments of the present invention may be supported by standard documents disclosed in at least one of IEEE 802.16m system, 3GPP system, 3GPP LTE system and 3GPP2 system, which are wireless access systems. That is, the steps or portions of the embodiments of the present invention that are not described in order to clearly illustrate the technical idea of the present invention can be supported by the documents. In addition, all terms disclosed in this document may be described by the standard document.

In addition, the specific terms used in the following description are provided to aid understanding of the present invention, and the use of such specific terms may be changed into other forms without departing from the technical idea of the present invention.

The term base station used in the present invention may be referred to as a cell or a sector when used in a regional concept. The serving base station (or cell) can be regarded as a base station that provides the existing main service to the terminal. In this sense, the serving base station (or cell) may be referred to as an anchor base station (or anchor cell).

Generally, a transmission signal transmitted from a transmission terminal can be expressed by the following Equation (1).

In Equation (1), H denotes a channel between a transmitter and a receiver, W denotes a precoding matrix to be multiplied when transmitting data symbols at a transmitter, x denotes a data symbol to be transmitted, I denotes interference, Respectively.

In particular, the following description will be made with reference to an uplink.

It is assumed that there are two terminals, a terminal A (Mobile Station-A), a terminal B (MS-B), two base stations, a base station A (BS) lets do it. If each terminal transmits to each base station, the received signal at the base station A can be expressed as Equation (2).

Where H _MS-AtoBS-A channel at the terminal B in the terminal A channel, H _MS-BtoBS-A to the base station A to base station A, W _MS-A is the precoding matrix of the terminal A, W _MS-B is a terminal B ≪ / RTI >

At this time, the reception performance of the base station A may be affected depending on how W _MS-B is selected. Therefore, if W _MS-B satisfying the following equation (3) is selected, the influence of the terminal B on the base station A can be minimized.

On the other hand, when the terminal B transmits to the base station B, in order to achieve the best performance, a precoding matrix satisfying the following Equation (4) must be selected.

Hereinafter, a multiple base station uplink MIMO operation will be described.

When CL MIMO precoding is applied to a serving cell and a neighboring cell, a time division duplex (TDD) scheme or a frequency division duplex scheme (FDD) scheme is used to mitigate inter- Duplex) It is possible to combine two PMIs in uplink transmission and perform single base station precoding together with multi-BS coordination. One of the PMIs maximizes the transmission power of the serving cell and the other minimizes the interference that occurs to neighboring cells.

PMI coupling follows the following order.

2 is a flowchart illustrating a method of notifying a UE of PMI-related information in a multi-base station uplink MIMO from the position of a base station.

(1) PMI binding may be initiated spontaneously by the base station. Based on the channel measurement, the base station can transmit an Uplink Codebook Coordination Enable (UCCE) signal for notifying a PMI combining operation to a terminal through a Media Access Control (MAC) message of a higher layer (S201).

(2) A periodic feedback header is received from the terminal receiving the MAC control message together with the requested information (S202). This information may include a Temp_BSID (Temp_Base Station ID) and a corresponding RSSI (Received Signal Strength Indicator) difference level.

The UE calculates the difference between two RSSIs received from the serving BS and the neighbor BS. If the RSSI difference value of the UE is smaller than the threshold value T, the UE can select the neighboring cell that receives the largest interference through Equation (5).

In Equation (5), i represents the index of the UE, p represents the index of the serving BS, and q represents the index of the neighbor BS. RSSI _{P, i} represents the RSSI measured by the terminal i from the preamble transmitted by the serving base station p, and RSSI _{q, i} represents the RSSI measured by the terminal i from the preamble transmitted by the neighboring base station q. .

After selecting the neighboring base station, the following equation (6) is performed by the terminal i to determine the RSSI difference level indicated by RSSI _diff .

In Equation (6), T ₀ is larger than T, and b 1 and b 2 are values obtained by quantizing the difference between RSSIs. Therefore, at least one bit is required for feedback.

(3) After receiving feedback from a plurality of terminals, the serving base station selects several terminals according to the RSSI difference level and the number of terminals supported by the sounding channel. The serving base station should notify the selected mobile station to transmit a sounding signal using all subcarriers in a sounding allocation through a unit target resource unit (UTRU) (S203). The uplink sounding channel for a plurality of terminals of a plurality of cells is notified by control information (for example, a sounding command A (Advanced) -MAP IE (Information Element) in IEEE 802.16m) Lt; / RTI > can be multiplexed through the cell cyclic shift separation and the user cyclic shift separation.

(4) PMI binding may be initiated at the base station spontaneously. Using the uplink sounding signal, the serving BS and the neighbor BS can measure the channel of the selected UEs. At the time of channel measurement, the serving BS and the neighbor BS can determine the PMI that maximizes the transmission power of the serving cell and the PMI _Min that minimizes the interference that occurs to the neighboring cell (S204). The neighboring base station can inform the serving base station of the PMI _Min through a backhaul network.

Two PMIs in the predefined codebook W _i can be selected by the following equations (7) and (8).

In Equations (7) and (8), H _S and H _I represent channel information from the terminal i to the serving BS and the neighbor BS, respectively. v _i is the i-th code word of the basic codebook. The PMI that maximizes the reception performance of the serving base station is obtained through Equation (7), and the PMI _Min that minimizes the interference of the neighboring base station through Equation (8) can be obtained.

(5) The serving BS informs the UE of the PMI that maximizes the transmission power of the serving cell using the control information A-MAP IE and informs the MS of the PMI _Min using a higher layer MAC Control message (S205).

FIG. 3 is a flowchart illustrating a method for determining a precoding matrix applied to uplink transmission in a multi-base station uplink MIMO according to an embodiment of the present invention.

The terminal determines an adjustment factor a (K ₁ , K ₂ , K ₃ ) based on T ₁ and T ₂ which are criteria for two fixed RSSI differences (S 301). The above can be determined using the following equation (9).

In Equation (9), i represents the index of the UE, p represents the index of the serving BS, and q represents the index of the neighbor BS. RSSI _{P, i} represents the RSSI measured by the terminal i from the preamble transmitted by the serving base station p, and RSSI _{q, i} represents the RSSI measured by the terminal i from the preamble transmitted by the neighboring base station q. .

를 이용하여 두 개의 프리코딩 행렬 (

,

)를 결합하여 프리코딩 행렬 W를 생성한다(S302). 다음의 수학식 10은 프리코딩 행렬

를 계산하는 방법을 나타낸다. The UE calculates the PMI and PMI _Min received from the base station and the PMI

Lt; / RTI > using two precoding matrices < RTI ID =

,

) To generate a precoding matrix W (S302). The following equation (10)

. ≪ / RTI >

The method described so far may be undesirable from the viewpoint of system performance because the amount of operations to be performed by the terminal and the base station is large. Therefore, a method for improving the performance of the system while reducing the number of operations to be performed by the base station and the terminal will be described.

In the method described above, the base station informs the start of the PMI combining through the UCCE separately, and then starts the operation, but suggests omitting this operation by informing PMI _Min .

Also, in the above-described method, the terminal informs the base station of the RSSI between the neighboring base station and the serving base station. The serving base station selects the terminals using the RSSI and notifies the UTRU of where to transmit the sounding channel.

However, in a general case, the UE informs the BS through the sounding channel with the channel information between the BS and the UE, which is different from a good channel according to the channel state of the serving cell, rather than based on the operation on the neighboring cell. Accordingly, the serving base station informs the terminal to transmit a sounding channel to a certain band. Also, by sharing such information between the base stations, the neighboring base station knows that a specific terminal transmits a sounding channel at a specific time through a certain band, and the neighboring base station acquires channel information between neighboring base stations from the terminal by monitoring the corresponding band . At this time, the neighboring base station can determine the strength of the received signal.

4 is a flowchart illustrating a method for transmitting PMI-related information to a UE in a multi-base station uplink MIMO according to an exemplary embodiment of the present invention, from the viewpoint of a serving BS.

Referring to FIG. 4, a neighboring BS transmits information such as a PMI _Min and a received signal strength to a serving BS (S401).

The serving BS determines the PMI using the channel information between the UE and the serving BS and determines the PMI combination ratio (PCR) using the information (for example, PMI _Min ) received from the neighboring cell (S402). The strength of the received signal between the serving base station and the corresponding terminal may also be used. In this case, the PCR can be largely set when the performance of the serving base station is more important, and the PCR can be set to be small when the interference to the neighboring base stations is to be reduced.

The serving BS transmits the PMI to the MS using the A-MAP IE, and transmits the PMI _Min and the PCR to the MS through the MAC control message (S403).

5 is a flowchart illustrating a method of determining a precoding matrix applied to uplink transmission in a multi-base station uplink MIMO according to an exemplary embodiment of the present invention.

Referring to FIG. 5, the UE receives an A-MAP IE carrying a PMI and receives a MAC control message for carrying a PMI _Min and a PCR (S501). The terminal generates / determines / calculates a precoding matrix W using PMI, PMI _Min, and PCR (S502). The UE applies the precoding matrix W to uplink transmission. The MS precodes its uplink signal to the precoding matrix W and transmits the precoded uplink signal to the serving BS.

The precoding matrix W is generated / determined / computed according to Equation (11).

According to the method proposed by the present invention, the operation at the serving base station is simplified. The terminal obtains only W using PMI and PMI _Min and PCR received from the serving base station. Therefore, the operation on the terminal side is simplified. Therefore, the operation of the entire system is simplified, and the number of operations in the terminal is reduced, so that the performance of the entire system can be improved.

6 is a block diagram illustrating a configuration of a device applicable to a base station and a terminal and capable of performing the above-described method.

As shown in FIG. 6, the device 100 includes a processing unit 101, a memory unit 102, and a radio frequency (RF) unit 103. The device 100 may further include a display unit 104 and / or a user interface unit 105. The device 100 may be provided in a base station and a terminal. A layer of the physical interface protocol is performed in the processing unit 101. The processing unit 101 provides a control plane and a user plane. The function of each layer can be performed in the processing unit 101. [ The processing unit 101 may perform the above-described embodiment of the present invention. Specifically, the processing unit 101 may perform a function of generating a subframe for terminal positioning or receiving the subframe to determine the position of the terminal. The memory unit 102 is electrically connected to the processing unit 101 and stores an operating system, an application program, and general files. If the device 100 is a terminal, the display unit 104 may display various information and may be implemented using a known Liquid Crystal Display (OLED), an Organic Light Emitting Diode (OLED), or the like. The user interface unit 105 may be configured in combination with a known user interface such as a keypad, a touch screen, and the like. The RF unit 103 is electrically connected to the processing unit 101 and transmits or receives radio signals.

The processing unit 101, the memory unit 102, the RF unit 103 and the display unit 104 interlock with each other and the processing unit is connected to the memory unit 102, the RF unit 103, And controls the operation of the display unit 104.

At the serving base station, the processing unit 101 may determine the PMI that maximizes the transmit power of the serving cell to which the serving base station belongs. In the neighboring base station, the processing unit 101 can inform the serving base station determines the PMI _Min to minimize the interference caused to the adjacent cell, the PMI _Min through a back holmang. The processing unit 101 of the neighboring base station can control its RF unit 103 to transmit the PMI _Min to the serving base station. The processing unit 101 of the serving base station can control its RF unit to transmit the PMI, the PMI _Min, and the PCR to the terminal. The RF unit 103 of the serving base station can receive the PMI _Min transmitted from the RF unit of the neighboring base station. The processing unit 101 of the serving base station can determine the PCR based on the PMI and / or the signal strength received from the terminal. The processing unit 101 of the serving base station may generate a control information element (e.g., A-MAP IE) including the PMI and a MAC (upper layer) message including the PMI _Min and the PCR . The processing unit 101 of the serving base station may control the RF unit to transmit the control information element and the MAC message to the terminal (103).

At the terminal, the RF unit 103 receives the PMI, the PMI _Min, and the PCR transmitted from the serving base station and delivers it to the processing unit 101. The processing unit 101 may generate / calculate / acquire a precoding matrix W for uplink transmission using the PMI, the PMI _Min, and the PCR. The processing unit 101 may precode the uplink data to the precoding matrix W and cause the RF unit 103 to transmit the precoded uplink data to the serving base station. The processing unit 101 may generate / calculate / obtain the precoding matrix W by Equation (11).

The embodiments described above are those in which the elements and features of the present invention are combined in a predetermined form. Each component or feature shall be considered optional unless otherwise expressly stated. Each component or feature may be implemented in a form that is not combined with other components or features. It is also possible to construct embodiments of the present invention by combining some of the elements and / or features. The order of the operations described in the embodiments of the present invention may be changed. Some configurations or features of certain embodiments may be included in other embodiments, or may be replaced with corresponding configurations or features of other embodiments. It is clear that the claims that are not expressly cited in the claims may be combined to form an embodiment or be included in a new claim by an amendment after the application.

In the present invention, a UE may be replaced with a mobile station (MS), a subscriber station (SS), a mobile subscriber station (MSS), or a mobile terminal.

Meanwhile, the UE of the present invention includes a PDA (Personal Digital Assistant), a cellular phone, a PCS (Personal Communication Service) phone, a GSM (Global System for Mobile) phone, a WCDMA (Wideband CDMA) Can be used.

Embodiments of the present invention may be implemented by various means. For example, embodiments of the present invention may be implemented by hardware, firmware, software, or a combination thereof.

For a hardware implementation, the method according to embodiments of the present invention may be implemented in one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs) , Field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of an implementation by firmware or software, the method according to embodiments of the present invention may be implemented in the form of a module, a procedure or a function for performing the functions or operations described above. The software code can be stored in a memory unit and driven by the processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various well-known means.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the foregoing detailed description should not be construed in a limiting sense in all respects, but should be considered as illustrative. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention. In addition, claims that do not have an explicit citation in the claims may be combined to form an embodiment or included in a new claim by amendment after the application.

The present invention can be used in a terminal, a base station, or other equipment of a wireless mobile communication system.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention. Accordingly, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (16)

In a wireless communication system supporting multiple base station uplink multiple input multiple output (MIMO), a base station transmits precoding information for uplink transmission,
Determining a precoding matrix index (PMI) that maximizes transmission performance between the UE and the BS;
Receiving a PMI _Min from the neighboring base station to minimize interference between the terminal and the neighboring base station; And
And transmitting to the terminal a PMI combining ratio (PCR) used to combine the PMI and the PMI _Min to generate the PMI, the PMI _Min , and the uplink precoding matrix W,
A method for transmitting precoding information. The method according to claim 1,
Wherein the PCR satisfies 0 ≤ PCR ≤ 1,
A method for transmitting precoding information. 3. The method according to claim 1 or 2,
Wherein the PMI is transmitted via a control information element and the PMI _Min and the PCR are transmitted via a medium access control (MAC)
A method for transmitting precoding information. In a wireless communication system supporting multiple base station uplink multiple input multiple output (MIMO), a UE determines a precoding matrix for uplink transmission,
A precoding matrix index (PMI) that maximizes transmission performance between the MS and the serving BS, a PMI _Min that minimizes interference between the MS and the neighbor BS, a PMI combining ratio (PCR) used to combine the PMI and the PMI _Min ) From the serving base station; And
And generating an uplink precoding matrix W using the PMI, the PMI _Min, and the PCR.
A method for determining a precoding matrix. 5. The method of claim 4,
Precoding the uplink data to the uplink precoding matrix W;
Transmitting the precoded uplink data,
A method for determining a precoding matrix. 6. The method of claim 5,
Wherein the PCR satisfies 0 ≤ PCR ≤ 1,
A method for determining a precoding matrix. 7. The method according to any one of claims 4 to 6,
Wherein the PMI is received via a control information element and the PMI _Min and the PCR are received via a medium access control (MAC)
A method for determining a precoding matrix. 8. The method of claim 7,
The uplink precoding matrix W may be expressed as:

, Where W _PMI denotes a precoding matrix corresponding to the PMI,

Represents a precoding matrix corresponding to the PMI _Min ,
A method for determining a precoding matrix. 1. A base station in a wireless communication system supporting multiple base station uplink multiple input multiple output (MIMO)
A receiving unit configured to receive a PMI _Min from the neighboring base station to minimize interference between the terminal and the neighboring base station;
A processing unit electrically connected to the receiving unit and configured to determine a precoding matrix index (PMI) that maximizes transmission performance between the terminal and the base station; And
A PMI combining ratio (PMI) used to combine the PMI and the PMI _Min to produce the PMI, the PMI _Min , and the uplink precoding matrix W under the control of the processing unit PCR) to the terminal,
Base station. 10. The method of claim 9,
Wherein the PCR satisfies 0 ≤ PCR ≤ 1,
Base station. 11. The method according to claim 9 or 10,
Wherein the processing unit controls the transmitting unit to transmit the PMI via a control information element and to transmit the PMI _Min and the PCR via a medium access control (MAC)
Base station. A terminal of a wireless communication system supporting multiple base station uplink multiple input multiple output (MIMO)
A precoding matrix index (PMI) that maximizes transmission performance between the MS and the serving BS, a PMI _Min that minimizes interference between the MS and the neighbor BS, a PMI combining ratio (PCR) used to combine the PMI and the PMI _Min A receiving unit configured to receive from the serving base station; And
And a processing unit configured to generate an uplink precoding matrix W using the PMI, the PMI _Min, and the PCR.
Terminal. 13. The method of claim 12,
Further comprising a transmission unit electrically connected to the processing unit,
Wherein the processing unit is configured to precode the uplink data to the uplink precoding matrix W and to control the transmission unit to transmit the precoded uplink data,
Terminal. 14. The method of claim 13,
Wherein the PCR satisfies 0 ≤ PCR ≤ 1,
Terminal. 15. The method according to any one of claims 12 to 14,
Wherein the PMI is received via a control information element and the PMI _Min and the PCR are received via a medium access control (MAC)
Terminal. 13. The method of claim 12,
The processing unit

To generate the precoding matrix W, where W _PMI denotes a precoding matrix corresponding to the PMI,

Represents a precoding matrix corresponding to the PMI _Min ,
Terminal.

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