JP5584708B2 - Method for performing CoMP operation and method for transmitting feedback information in a wireless communication system - Google Patents

Description

  The present invention relates to a wireless communication system, and more particularly to a method for performing a CoMP operation in a wireless communication system.

  Coordinated Multi-Point (CoMP) system (hereinafter referred to as CoMP system) is located at a cell boundary by applying MIMO (Multiple-Input Multiple-Output) transmission in a multi-cell environment. It is a system for improving the processing amount of the user who performs. When a CoMP system is applied, inter-cell interference can be reduced in a multi-cell environment. When using such a CoMP system, terminals can receive data support jointly from a multi-cell base station.

  In addition, each base station can improve system performance by simultaneously supporting one or more terminals (UE 1, UE 2,... UE K) using the same radio frequency resource. In addition, the base station can perform a space division multiple access (SDMA) method based on channel state information (CSI) between the base station and the terminal.

  Such a CoMP scheme includes joint processing (JP: Joint Processing) and cooperative scheduling scheme / beamforming scheme (CS / CB: Coordinated Scheduling scheme / Beamforming scheme) using data sharing. And can be classified.

  FIG. 1 is a diagram conceptually illustrating CoMP of an existing intra base station (intra eNB) and an inter base station (inter eNB).

  Referring to FIG. 1, intra base stations 110 and 120 and an inter base station 130 exist in a multi-cell environment. In LTE (Long Term Evolution), an intra base station is composed of several cells (or sectors). The cell belonging to the base station to which the specific terminal belongs has a relationship between the specific terminal and the intra base stations 110 and 120. That is, a cell sharing the same base station as the cell to which the terminal belongs is a cell corresponding to the intra base stations 110 and 120, and a cell belonging to another base station is a cell corresponding to the inter base station 130. In this way, cells based on the same base station as the specific terminal exchange information (for example, data, channel state information (CSI: Channel State Information) via the x2 interface, etc., but other base stations The base cell can exchange information between cells via the backhaul 140 or the like.

  As shown in FIG. 1, a single cell MIMO user 150 in a single cell communicates with one serving base station in a cell (sector), and a multi-cell MIMO user 160 located at a cell boundary is It can communicate with multiple serving base stations in multiple cells (sectors).

  Hereinafter, a spatial channel matrix used for feedback information will be briefly described.

ここで、Ｈ（ｉ，ｋ）は、空間チャネル行列であり、ｈ_ｒ，ｔ（ｉ，ｋ）は、チャネル行列Ｈ（ｉ，ｋ）の要素、Ｎｒは受信アンテナ個数、Ｎｔは送信アンテナ個数、ｒは受信アンテナのインデックス、ｔは送信アンテナのインデックス、ｉはＯＦＤＭ（または、ＳＣ−ＦＤＭＡ）シンボルのインデックス、ｋは副搬送波のインデックスを表す。

Here, H (i, k) is a spatial channel matrix, h _{r, t} (i, k) is an element of the channel matrix H (i, k), Nr is the number of receiving antennas, and Nt is the number of transmitting antennas. , R is a receive antenna index, t is a transmit antenna index, i is an OFDM (or SC-FDMA) symbol index, and k is a subcarrier index.

は、チャネル行列Ｈ（ｉ，ｋ）の要素（ｅｌｅｍｅｎｔ）であり、ｉ番目のシンボル及びｋ番目の副搬送波上におけるｒ番目のチャネル状態及びｔ番目のアンテナを意味する。
また、本発明で使用可能な空間チャネル共分散行列（ｓｐａｔｉａｌ ｃｈａｎｎｅｌ ｃｏｖａｒｉａｎｃｅ ｍａｔｒｉｘ）について簡略に説明する。空間チャネル共分散行列は、記号Ｒで表すことができる。

Is an element of the channel matrix H (i, k), meaning the r th channel state and the t th antenna on the i th symbol and the k th subcarrier.
Also, a spatial channel covariance matrix usable in the present invention will be briefly described. The spatial channel covariance matrix can be represented by the symbol R.

であり、ここで、Ｈは空間チャネル行列を、Ｒは空間チャネル共分散行列を意味する。Ｅ［］は、平均（ｍｅａｎ）を意味し、ｉはシンボルインデックス、ｋは周波数インデックスを意味する。

Where H is the spatial channel matrix and R is the spatial channel covariance matrix. E [] means the mean, i is the symbol index, and k is the frequency index.

  Singular value decomposition (SVD) is one of the important methods for decomposing rectangular matrices, and is a technique often used in the field of signal processing and statistics. The singular value decomposition is a generalization of the spectrum theory of a matrix to an arbitrary rectangular matrix. When the spectrum theory is used, an orthogonal square matrix can be decomposed into a diagonal matrix based on eigenvalues. Let the matrix H be an m × m matrix composed of real or complex set elements. In this case, the matrix H can be represented by the product of three matrices as follows.

ここで、Ｕ、Ｖは、ユニタリー行列（ｕｎｉｔａｒｙ ｍａｔｒｉｘ）を表し、Σは、負でない特異値を含むｍ×ｎ対角行列である。特異値は

Here, U and V represent unitary matrices, and Σ is an m × n diagonal matrix including non-negative singular values. The singular value is

である。このように３つの行列の積で表すことを、特異値分解という。特異値分解は、直交正方行列のみを分解できる固有値分解に比べてはるかに一般的な行列を扱うことができる。このような特異値分解と固有値分解は相互関連している。

It is. Such a product of three matrices is called singular value decomposition. Singular value decomposition can handle much more general matrices than eigenvalue decomposition, which can decompose only orthogonal square matrices. Such singular value decomposition and eigenvalue decomposition are interrelated.

  When matrix H is a Hermitian matrix with a positive constant sign, all eigenvalues of H are non-negative real numbers. At this time, the singular values and singular vectors of H are real numbers in which all eigenvalues of H are not negative. The singular value and singular vector of H are the same as the eigenvalue and eigenvector of H.

  On the other hand, eigenvalue decomposition (EVD) can be expressed as follows.

ここで、固有値は、λ_１，…，λ_ｒになることができる。

Here, eigenvalues, λ _1, ..., can be a λ _r.

  Up to now, since the terminal transmits only the PMI value as feedback information, it is difficult for the base station to determine the ranking for the PMI value. From such a PMI ranking problem, efficiency and There was a problem that accuracy decreased.

  The technical problem to be achieved by the present invention is to provide a method for performing a CoMP operation and a method for transmitting feedback information in a wireless communication system.

  Another technical problem to be achieved by the present invention is to provide a terminal device that performs CoMP operation in a wireless communication system and transmits feedback information.

  Still another technical problem to be achieved by the present invention is to provide a base station apparatus that performs CoMP operation in a wireless communication system.

  The technical problem to be achieved by the present invention is not limited to the above-mentioned technical problem, and other technical problems not mentioned can be obtained from the following description based on the general knowledge in the technical field to which the present invention belongs. It will be clear to those who have it.

  In order to achieve the above technical problem, the CoMP feedback information transmission method according to the present invention provides PMI (Precoding Matrix Index) set information to be restricted or recommended for a specific neighboring cell that performs the CoMP operation. And the signal strength or interference level calculated by applying the PMI set to the specific neighboring cell and the signal strength or interference level calculated when the PMI set information is not applied. Transmitting a signal strength gain value or an interference level gain value, which is a gain value corresponding to the difference between the two, to the serving base station.

  In order to achieve the above technical problem, the CoMP feedback information transmission method according to the present invention uses a reference signal received from one or more neighboring cells and uses noise and interference dispersion values corresponding to signal strength or interference level. Measuring noise and interference dispersion information including the measured noise and interference dispersion value, and PMI (Precoding Matrix Index) information to be restricted or recommended for a specific neighboring cell performing the CoMP operation to the serving base station Transmitting.

In order to achieve the above technical problem, a terminal apparatus according to the present invention uses a reference signal received from one or more neighboring cells to measure noise and interference variance including signal strength or interference level. Module, transmission for transmitting noise and interference dispersion information including the measured noise and interference dispersion value, and PMI (Precoding Matrix Index) information to be restricted or recommended for a specific neighboring cell performing the CoMP operation to a serving base station Module.
This specification also provides the following items, for example.
(Item 1)
A method in which a terminal transmits feedback information in a wireless communication system in which one or more base stations perform CoMP (Coordinated Multi-Point) operation,
PMI (Precoding Matrix Index) set information to be restricted or recommended for a specific neighboring cell performing the CoMP operation is transmitted to the serving base station,
Corresponds to the difference between the signal strength or interference level calculated by applying the PMI set to the specific neighboring cell and the signal strength or interference level calculated when the PMI set information is not applied. Transmitting a signal strength gain value or an interference level gain value which is a value to the serving base station;
A CoMP feedback information transmission method.
(Item 2)
The signal strength or interference level includes a signal-to-interference plus noise ratio (SINR) value, a reference signal received power (RSRP), and a reference signal received quality (RSRQ). ), A reference signal strength indicator (RSSI: Reference Signal Strength Indicator), a PD (Propagation Delay), and a carrier-to-interference plus noise ratio (CINR) value. CoMP feedback information transmission method according to item 1
(Item 3)
A method in which a terminal transmits feedback information in a wireless communication system that performs CoMP (Coordinated Multi-Point) operation,
Measure noise and interference variance values corresponding to signal strength or interference level using reference signals received from one or more neighboring cells,
Transmitting noise and interference dispersion information including the measured noise and interference dispersion value, and PMI (Precoding Matrix Index) information to be restricted or recommended for a specific neighboring cell performing the CoMP operation, to a serving base station;
A CoMP feedback information transmission method.
(Item 4)
The noise and interference variance information includes noise and interference variance values when PMI that is desired to be restricted or recommended for specific neighboring cells performing the CoMP operation is applied, and noise and interference variance values when the PMI is not applied. 4. The CoMP feedback information transmission method according to item 3, including first noise corresponding to the difference value and interference dispersion information.
(Item 5)
4. The CoMP feedback information transmission method according to item 3, wherein the noise and interference dispersion information further includes second noise and interference dispersion information corresponding to noise and interference dispersion values for a cell not performing the CoMP operation.
(Item 6)
The CoMP according to item 5, wherein the noise and interference dispersion information further includes third noise and interference dispersion information corresponding to a value calculated by applying the limited or recommended PMI information to the specific CoMP neighboring cell. Feedback information transmission method.
(Item 7)
The noise and interference variance information is a value corresponding to the difference between the noise and interference variance value before applying the restricted or recommended PMI information to the specific CoMP neighboring cell and the noise and interference variance value when applied. The CoMP feedback information transmission method according to item 5, further including fourth noise and interference dispersion information.
(Item 8)
The noise and interference variance information includes the noise and interference variance value calculated by applying the PMI to be restricted to the specific CoMP neighboring cell, and the noise and interference variance value calculated by applying the recommended PMI. Item 6. The CoMP feedback information transmission method according to Item 5, further including fifth noise and interference dispersion information corresponding to.
(Item 9)
The noise and interference variance information is the difference between the noise and interference variance calculated by applying PMI to be restricted to the specific CoMP neighboring cell and the noise and interference variance calculated by applying the recommended PMI. Item 6. The CoMP feedback information transmission method according to Item 5, further including sixth noise and interference dispersion information that are values corresponding to.
(Item 10)
The noise and interference variance information further includes seventh noise and interference variance information corresponding to noise and interference variance values calculated by applying PMI information restricted or recommended for the entire cell performing the CoMP operation. 6. The CoMP feedback information transmission method according to item 5.
(Item 11)
The noise and interference variance information includes noise and interference variance values for the entire cell performing the CoMP operation before applying the received PMI to the specific CoMP neighboring cell, and noise and interference calculated by applying the noise and interference variance information. 6. The CoMP feedback information transmission method according to item 5, further including eighth noise and dispersion information that are values corresponding to a difference from the dispersion value.
(Item 12)
6. The CoMP feedback information transmission method according to item 5, wherein the noise and interference dispersion information further includes noise and dispersion value information for a serving cell.
(Item 13)
The noise and interference dispersion information is obtained by applying the noise and interference dispersion value for the cell not performing the CoMP operation, or the restricted or recommended PMI information to the specific CoMP neighboring cell, together with the noise and dispersion value for the serving cell. Item 13. The CoMP feedback information transmission method according to Item 12, further comprising information of a value expressed using the calculated noise and interference variance value.
(Item 14)
The noise and interference variance information includes the noise and the variance value for the serving cell, the noise and interference variance value for the cell that does not perform the CoMP operation, or the noise and variance before applying the received PMI to the specific CoMP neighboring cell. Item 13. The CoMP feedback information transmission method according to Item 12, further including information of a value expressed using a value corresponding to a difference between the value and the noise and variance value calculated by application.
(Item 15)
A method in which a base station performs a CoMP operation in a wireless communication system,
PMI (Precoding Matrix Index) information that the terminal desires to limit or recommend to the base station, and noise and interference dispersion information including signal strength or interference level for one or more neighboring cells measured by the terminal Receive
Generating PMI ranking information for limiting or recommending to the terminal based on the received PMI information and the noise and interference dispersion information;
A CoMP operation method including:
(Item 16)
A terminal device that transmits feedback information in a wireless communication system that performs CoMP (Coordinated Multi-Point) operation,
A measurement module for measuring noise and interference variance including signal strength or interference level using reference signals received from one or more neighboring cells;
A transmission module for transmitting noise and interference dispersion information including the measured noise and interference dispersion value, and PMI (Precoding Matrix Index) information to be restricted or recommended for a specific neighboring cell performing the CoMP operation to a serving base station; ,
Including a terminal device.

  According to the present invention, the terminal and the base station can perform the CoMP operation more efficiently.

  The effects obtained from the present invention are not limited to the effects mentioned above, and other effects not mentioned are apparent to those having ordinary knowledge in the technical field to which the present invention belongs from the following description. I will.

The accompanying drawings, which are included as part of the detailed description to assist in understanding the present invention, provide examples of the present invention and together with the detailed description, explain the technical idea of the present invention.
It is a figure which shows notionally CoMP of the existing intra base station (intra eNB) and the inter base station (intere NB). It is a figure for demonstrating the physical channel used for 3GPP (3rd Generation Partnership Project) LTE (Long Term Evolution) system which is an example of a mobile communication system, and the general signal transmission method using these. It is a figure for demonstrating the concept in which the terminal and base station which concern on this invention perform CoMP operation | movement. It is a block diagram which shows the suitable Example of the terminal device which concerns on this invention.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. The detailed description disclosed below in connection with the appended drawings is intended as a description of exemplary embodiments of the invention and is not intended to represent the only embodiments in which the invention may be practiced. The following detailed description includes specific details in order to provide a thorough understanding of the present invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. For example, the following detailed description will be specifically described on the assumption that the mobile communication system is a 3GPP LTE system, but can be applied to any other mobile communication system except for matters specific to 3GPP LTE.

  In some cases, well-known structures and devices may be omitted or block diagram formats centered around the core functions of each structure and device may be used to avoid obscuring the concepts of the present invention. Further, the same components are denoted by the same reference numerals throughout the specification.

  In the following description, a terminal (or user equipment) is a generic term for a mobile or fixed user end equipment including a UE (User Equipment), an MS (Mobile Station), and the like. The base station is a generic term for any node at the end of the network that communicates with the terminal, including Node B, eNode B, Base Station, and the like.

  In a mobile communication system, a terminal (User Equipment) can receive information from a base station through a downlink, and the terminal can also transmit information through an uplink. Information transmitted or received by the terminal includes data and various control information, and various physical channels exist depending on the type and use of information transmitted or received by the terminal.

  FIG. 2 is a diagram for explaining a physical channel used in a 3GPP (3rd Generation Partnership Project) LTE (Long Term Evolution) system, which is an example of a mobile communication system, and a general signal transmission method using them.

  In step S201, a terminal that is turned on again or enters a new cell while the power is turned off performs an initial cell search operation such as synchronization with the base station. For this purpose, the terminal receives a primary synchronization channel (P-SCH) and a secondary synchronization channel (S-SCH: Secondary Synchronization Channel) from the base station, and synchronizes with the base station to obtain information such as a cell ID. Can be earned. Thereafter, the terminal can acquire the broadcast information in the cell by receiving a physical broadcast channel from the base station. Meanwhile, the UE can receive a downlink reference signal (DL RS) in an initial cell search stage and check a downlink channel state.

  In step S202, the UE that has completed the initial cell search receives a physical downlink control channel (PDCCH: Physical Downlink Control Channel) and a physical downlink shared channel (PDSCH) corresponding to the physical downlink control channel information. And more specific system information can be acquired.

  On the other hand, when there is no radio resource for first connection or signal transmission to the base station, the terminal can perform a random access procedure (Random Access Procedure) as in steps S203 to S206. For this, the terminal transmits a specific sequence as a preamble through a physical random access channel (PRACH) (S203), and receives a response message for the random access through the PDCCH and the corresponding PDSCH. (S204). In the case of contention-based random access excluding the case of handover, a contention resolution procedure (Contention Resolution Procedure) such as transmission of additional PRACH (S205) and reception of PDCCH / PDSCH (S206) is performed thereafter. It can be carried out.

  The terminal that has performed the above procedure thereafter receives a PDCCH / PDSCH (S207) and a physical uplink shared channel (PUSCH) / physical uplink as a general uplink / downlink signal transmission procedure. Transmission of a control channel (PUCCH: Physical Uplink Control Channel) can be performed (S208). At this time, the control information transmitted from the terminal to the base station through the uplink or received from the base station by the terminal includes a downlink / uplink ACK / NACK signal, a channel quality indicator (CQI) / precoding. A matrix index (Precoding Matrix Index, PMI) / rank indicator (Rank Indicator, RI) and the like are included. In the 3GPP LTE system, a terminal can transmit control information such as CQI, PMI, and RI through PUSCH and / or PUCCH.

  The term base station in the present invention is also called a cell or a sector when used as a regional concept. A serving base station (or cell) can be referred to as a base station (or cell) that provides a main service to a terminal, and can transmit and receive control information on a cooperative multiple transmission point (coordinated multiple transmission point). . After this, the serving base station (or cell) can also be referred to as an anchor base station (or cell). The serving base station can transmit various information received from the terminal to the adjacent base station (cell). Similarly, an adjacent base station is also referred to as an adjacent cell when used as a regional concept. One CoMP set refers to a set of cells that perform CoMP operations.

  By using the CoMP scheme in a multi-cell environment, it is possible to improve the communication performance of terminals at cell boundaries. Such CoMP schemes include cooperative processing (JP: Joint Processing) using data sharing and cooperative scheduling / beam forging to reduce inter-cell interference, such as worst compensation and best compensation. (CS / CB: Coordinated Scheduling / Beamforming) method. Here, in the worst companion method, the terminal reports the PMI with the largest interference to the serving cell to the serving base station, so that the corresponding cell uses the second best PMI excluding the corresponding PMI. Thus, the inter-cell interference can be removed. The best companion method is a method of reducing inter-cell interference by reporting PMI with the least interference to a cell in which a terminal performs CoMP, so that the corresponding cell uses the corresponding PMI.

  In order to efficiently perform such a CoMP operation method, a terminal transmits measurement information (measurement information) such as an interference level (or signal strength) to a neighboring cell and transmits it to a serving base station or the like. It is necessary to define feedback information. That is, an efficient CoMP operation can be performed by defining a terminal measurement procedure and an overall operation procedure via a CoMP active set in a CoMP operation. Here, the CoMP active set refers to a transmission point set that serves a specific terminal and actually performs CoMP transmission.

  When operating in the cooperative scheduling and beamforming (CS / CB) method among the CoMP operation methods, the terminal restricts and / or recommends a neighboring cell performing the CoMP operation (hereinafter abbreviated as “CoMP neighboring cell”). The desired PMI information can be transmitted to the serving base station. When a large number of terminals perform CoMP operation, if the PMI information to be restricted and / or recommended for the CoMP neighboring cell increases, the corresponding CoMP neighboring cell may be restricted and / or recommended PMI from the received PMI information. Is preferably selected. Accordingly, the CoMP neighbor cell that has received the PMI restriction and / or recommendation request of the terminal can determine the ranking of the PMI to be restricted and / or recommended. As described above, the CoMP neighbor cell can determine the rank of the PMI to be restricted and / or recommended using the received restriction or / and recommended PMI information. However, it is not preferable to determine the PMI for the PMI restriction and / or recommendation request using only the PMI information received by the CoMP neighboring cell.

  Therefore, the present invention proposes a method for enabling CoMP neighbor cells to efficiently determine the PMI order. As one of the proposed methods, the terminal can consider a method of transmitting not only PMI information but also other additional information to a serving base station that performs CoMP operation. The terminal can transmit such additional information 1) when configuring a CoMP set, 2) when transmitting PMI information in CoMP operation, and the like.

  First, a method in which a terminal transmits additional information when a CoMP set is configured will be described.

  The CoMP set may be configured based on measurement information such as an interference level (or signal strength) measured by a terminal with respect to a neighboring cell. The CoMP set configuration has an advantage that the CoMP set configuration can be flexible by configuring the CoMP set for neighboring cells that directly affect the actual terminal based on the terminal measurement. The terminal can measure an interference level with respect to the neighboring cell based on the neighboring cell list. In this case, the terminal can receive a neighbor cell list from a serving base station or the like in advance for CoMP set configuration. Alternatively, the UE may form a neighbor cell list through measurement for direct neighbor cells.

  The measurement information related to the interference level (or signal strength) that the terminal measures with respect to the neighboring cell for the CoMP set configuration can be expressed in various forms of values. Examples of these various types of values include reference signal received power (RSRP), reference signal received quality (RSRQ), reference signal strength indicator (RSSI), and reference signal strength strength (RSSI). , PD (Propagation Delay), carrier-to-interference plus noise (CINR) measured for neighboring cells when neighboring cells use good PMI (good PMI) or bad PMI (bad PMI) Ratio or signal-to-interference and noise ratio (SINR: Signal to Interface) ance plus Noise Ratio) value, CINR value or SINR value measured when neighbor cell does not use good PMI or bad PMI (bad PMI), and previously measured CINR value or SINR value There is an improved CINR value or SINR value for the serving cell that compares the difference between the serving cell and informs whether the channel state of the serving cell has been improved to some extent. Of these, in particular, improved CINR or SINR values can help to determine PMI ranking in neighboring cells. The terminal may use the CINR value or SINR value measured when the terminal uses a good PMI recommended by the terminal in a neighboring cell or does not use the restricted bad PMI, and before applying the restricted and / or recommended PMI. A value corresponding to the difference between the measured CINR value or SINR value can be generated and transmitted to the base station. Since the neighboring cell that has received this information from the serving base station can grasp the degree of improvement in the channel state based on the difference value between the CINR value and the SINR value, the PMI order can be easily determined.

  As described above, in the LTE system, the UE measures the channel quality state between itself and the cell using the improved CINR value or SINR value corresponding to the pilot signal power, reference signal received power (RSRP), and the like. be able to. Here, the reference signal received power refers to a linear average of power distributed to resource elements to which a cell-specific reference signal is allocated within the considered measurement frequency bandwidth. The power of each resource element on the resource block can be determined by the energy received from the valid section of the symbol excluding the cyclic prefix (CP). Such reference signal received power is applicable to the terminal in both the RRC_idle state and the RRC_connected state of the terminal. Also, if receiver diversity is utilized by the terminal, the reported value is equal to the linear average of the power values of all diversity branches.

  In addition to the PMI information desired to be restricted and / or recommended for CoMP neighboring cells, the UE can further transmit the measurement values in the various forms described above to the serving base station. On the other hand, the terminal can transmit the measurement values of the above-described various forms additionally transmitted during the CoMP set configuration to the serving base station even during the CoMP operation, and measure the interference level with respect to the CoMP neighboring cell during the CoMP operation. Can be transmitted again to transmit the measurement values in the various forms to the serving base station.

  Based on such measurement of the terminal with respect to the adjacent cell (for example, measurement of reference signal reception power), the terminal can report information necessary for configuring the CoMP set to the serving base station. The information reported to the serving base station may include cell ID information of the corresponding neighboring cell together with one or more values of the measured values of the neighboring cell described above. When the terminal directly forms a neighbor cell list, the terminal can directly place the measured cell ID information on the corresponding neighbor cell on the list.

  When the serving base station provides a list of neighboring cells to the terminal in advance, the terminal transmits the RSRP value measured for the corresponding cell in the order of the cell ID defined in advance, and other than the measured value. In addition, an index corresponding to the cell ID can be further included and transmitted to the serving base station. Alternatively, the terminal can arrange the index information corresponding to the cell ID in the order of the interference level and transmit the interference level, which is a measurement value corresponding to the index and the index, to the serving base station.

  The serving base station can receive PMI information and interference level information that the terminal desires to limit and / or recommend for the CoMP neighboring cell from the terminal. Then, the serving base station can transmit the received PMI information and interference level information to the CoMP neighboring cell. The CoMP neighbor cell that has received such information can determine the PMI to be restricted and / or recommended by using the PMI information and the interference level information that the terminal desires to restrict and / or recommend. On the other hand, PMI ranking information can be generated. At this time, the CoMP neighbor cell may determine the PMI to be limited and / or recommended only by the PMI count (counting) without interference level information. That is, the PMI order can be determined based on the number of PMIs restricted and / or recommended for CoMP specific neighboring cells. However, if the number of terminals performing CoMP is small, or the number of PMIs requested to limit and / or recommend CoMP neighboring cells is the same, any PMI may be selected. The criteria may be ambiguous. Nevertheless, the CoMP neighbor cell can reduce the overhead burden associated with the additional transmission of feedback information by the UE and the BS by determining the PMI that receives the most restrictions and / or recommendations. Can do.

  In the CoMP operation, a case where PMI information and additional information are transmitted will be described.

  When configuring a CoMP set or performing a CoMP operation without configuring a CoMP set, the terminal can select a PMI to be restricted and / or recommended for a neighboring cell affected by interference, and transmit the selected PMI to the serving base station. When a terminal transmits a PMI to perform a cooperative scheduling method in performing a CoMP operation, the serving base station determines a PMI order using interference level information received from the terminal when configuring a CoMP set. Can be solved. That is, when the terminal uses interference level information or the like for the neighboring cell measured when the CoMP set is configured, only the PMI information for the neighboring cell can be transmitted to the serving base station during the CoMP operation. In this way, the PMI ranking determination problem can be solved with a small feedback overhead.

  On the other hand, during the CoMP operation, the terminal can transmit both interference level information and the like in addition to the PMI information for the CoMP neighboring cell. In the case of interference level information reported at the time of CoMP set configuration (in the case of a CoMP system that does not configure a CoMP set, initial relevant information), the interference level that changes with time may not be accurately reflected. Therefore, the terminal can solve such a problem by transmitting both the PMI information and the interference level information. At this time, the terminal can transmit PMI information, interference level information, and the like in the same transmission cycle, or can transmit in different transmission cycles.

  The additionally transmitted interference level information may be expressed in various forms of measurement values. This may be the same form as the measurement value that the terminal measures for the neighboring cell when the CoMP set is configured. For example, as described above, it is measured when the reference signal received power (RSRP), the reference signal received quality (RSRQ), the reference signal strength indicator (RSSI), the PD, and the neighboring cell use good PMI or bad PMI. Carrier-to-interference and noise ratio (CINR) values or signal-to-interference and noise ratio (SINR) values for neighboring cells, and CINR values measured when neighboring cells use good PMI or do not use bad PMI Or, there is an improved CINR value or SINR value for the serving cell that compares the difference between the SINR value and the previously measured CINR value or SINR value, etc. . Among other things, the improved CINR or SINR value can help to determine the PMI order in neighboring cells. The terminal may use the CINR value or SINR value measured when the terminal uses a good PMI recommended by the terminal in a neighboring cell or does not use the restricted bad PMI, and before applying the restricted and / or recommended PMI. A value corresponding to the difference between the measured CINR value or SINR value can be measured and generated and transmitted to the base station. Since the neighboring cell that has received this information from the serving base station can grasp the degree of improvement in the channel state based on the difference value between the CINR value and the SINR value, the PMI order can be easily determined. In this way, the terminal can measure the interference level difference between when the PMI set reported to the neighboring cell is applied to the neighboring cell and when the PMI set is not applied to the neighboring cell, and report it to the serving base station.

  In addition to a method in which a terminal transmits PMI information and interference level information (or related information) during CoMP operation, a method of transmitting PMI information and noise plus interference variance information can be considered. That is, to help the CoMP neighbor cell determine the PMI order, the UE transmits noise and interference dispersion information along with the PMI information, and the CoMP neighbor cell wants to efficiently limit and / or recommend. A PMI can be selected and a PMI ranking can be determined.

  Hereinafter, as a feedback information transmission method, a method in which a terminal transmits PMI information, noise, and interference dispersion information to a serving base station will be described. First, definitions regarding feedback information measured and transmitted by a terminal will be described.

は、端末がサービングセルに対して選択したＰＭＩ、

Is the PMI selected by the terminal for the serving cell,

は、端末がサービングセルに対して測定した雑音及び干渉分散（サービングセル信号の強度を意味できる。）、

Is the noise and interference variance measured by the terminal with respect to the serving cell (can mean the strength of the serving cell signal),

は、端末がＣｏＭＰ動作を行う各隣接セルに対して制限及び／または推奨を希望するＰＭＩ、

PMI that the terminal desires to restrict and / or recommend for each neighboring cell in which the terminal performs CoMP operation,

は、ＣｏＭＰ動作を行わない残りのセルに対する雑音及び干渉分散、

Is the noise and interference variance for the remaining cells not performing CoMP operation,

は、ＣｏＭＰ動作を行う各隣接セルで制限及び／または推奨ＰＭＩが適用された時における該当の隣接セルの雑音及び干渉分散（該当の隣接セルにおける信号の強度または干渉の強度）、

Is the noise and interference dispersion (signal strength or interference strength in the corresponding neighboring cell) when the restricted and / or recommended PMI is applied in each neighboring cell performing the CoMP operation,

は、ＣｏＭＰ動作を行う各隣接セルで制限及び／または推奨するＰＭＩが適用された時と適用されなかった時における該当の隣接セルの雑音及び干渉分散変化量（該当の隣接セルにおける信号の強度の変化量または干渉の強度の変化量）である。そして、

Is the noise and interference variance change amount of the corresponding neighbor cell when the restricted and / or recommended PMI is applied and not applied to each neighbor cell performing CoMP operation (the signal strength of the corresponding neighbor cell). Change amount or change amount of interference intensity). And

は、ＣｏＭＰ動作を行う各隣接セルに対して制限ＰＭＩが適用された時における該当の隣接セルの雑音及び干渉分散であり、

Is the noise and interference variance of the corresponding neighboring cell when the restricted PMI is applied to each neighboring cell performing the CoMP operation,

は、各ＣｏＭＰ動作を行う隣接セルに対して推奨ＰＭＩが適用された時における該当の隣接セルの雑音及び干渉分散であり、

Is the noise and interference variance of the neighboring cell when the recommended PMI is applied to the neighboring cell performing each CoMP operation,

は、ＣｏＭＰ動作を行う各隣接セルに対して制限ＰＭＩが適用された時と適用されなかった時における差値（該当の隣接セルにおける雑音及び干渉分散変化量）であり、

Is a difference value (noise and interference variance change amount in the corresponding neighboring cell) when the restricted PMI is applied and not applied to each neighboring cell performing the CoMP operation,

は、各ＣｏＭＰ動作を行う隣接セルに対して推奨ＰＭＩが適用された時と適用されなかった時における差値（該当の隣接セルにおける雑音及び干渉分散変化量）であり、

Is a difference value between when the recommended PMI is applied to a neighboring cell performing each CoMP operation and when the recommended PMI is not applied (noise and interference variance change amount in the neighboring cell),

は、各ＣｏＭＰ動作を行う隣接セルで制限及び／または推奨ＰＭＩが適用された時に端末が測定できる全体セルに対する雑音及び干渉分散値であり、

Is a noise and interference variance value for the whole cell that can be measured by the terminal when the restricted and / or recommended PMI is applied in neighboring cells performing each CoMP operation,

は、各ＣｏＭＰ動作を行う該当の隣接セルで制限及び／または推奨ＰＭＩが適用された時と適用されなかった時に端末が測定できる全体セルに対する雑音及び干渉分散の変化量である。以下、より具体的に、端末がサービング基地局に伝送する雑音及び干渉分散値の形態によって区別されるフィードバック情報伝送例を説明する。

Is the amount of change in noise and interference variance for the entire cell that can be measured by the terminal when the restricted and / or recommended PMI is applied and not applied in the corresponding neighboring cell performing each CoMP operation. Hereinafter, an example of feedback information transmission distinguished according to the form of noise and interference dispersion value transmitted from the terminal to the serving base station will be described.

  As one method of transmitting noise and interference dispersion information, a terminal located at a cell boundary performs PMP information to a serving base station on PMI information desired to be restricted and / or recommended for CoMP neighboring cells that perform CoMP operation. Can be transmitted along with noise and interference variance information for the remaining cells.

  As another method of transmitting noise and interference dispersion information, the UE may limit and / or recommend CoMP neighboring cells to PMI information and noise and interference dispersion for the remaining cells not performing CoMP operation.

に加えて、ＣｏＭＰ隣接セルに制限または推奨ＰＭＩが適用された時における雑音及び干渉分散値

In addition, noise and interference variance values when restricted or recommended PMI is applied to CoMP neighboring cells

をさらに伝送することができる（ここで、Ｎは、ＣｏＭＰ動作を行うセルのうち、干渉を与えているセルのインデックスを意味する）。

(Where N is the index of the cell giving interference among the cells performing the CoMP operation).

値は、特定ＣｏＭＰ隣接セルに限定された雑音及び干渉分散値である。この雑音及び干渉分散値に基づき、この特定ＣｏＭＰ隣接セルに制限または推奨ＰＭＩが適用された時と適用されなかった時における雑音及び干渉分散変化量を

The values are noise and interference variance values limited to specific CoMP neighbor cells. Based on this noise and interference variance value, the noise and interference variance change amount when the restricted or recommended PMI is applied to this specific CoMP neighboring cell and when it is not applied is calculated.

のように表現することができる。すなわち、端末は、制限及び／または推奨するＰＭＩ、

It can be expressed as That is, the terminal can restrict and / or recommend PMI,

をサービング基地局に伝送してもよく、制限及び／または推奨するＰＭＩ、

May be transmitted to the serving base station, and PMI to restrict and / or recommend,

の全てを伝送してもよい。

May be transmitted.

  Further, as another method, the restriction on the cell in which the terminal performs the CoMP operation and / or the recommended PMI and the noise and interference dispersion value for the remaining cell not performing the CoMP operation

に加えて、特定ＣｏＭＰ隣接セルに制限ＰＭＩが適用された時における雑音及び干渉分散値

In addition, noise and interference variance values when restricted PMI is applied to specific CoMP neighboring cells

と、推奨するＰＭＩが適用された時における雑音及び干渉分散値

And noise and interference variance values when the recommended PMI is applied

をさらにサービング基地局に伝送することができる。または、端末はサービング基地局に、

Can be further transmitted to the serving base station. Or the terminal can serve the serving base station,

値の差値である

Difference value

を伝送することもできる。または、端末が制限及び／または推奨するＰＭＩ、

Can also be transmitted. Or PMI restricted and / or recommended by the terminal,

情報の全てをサービング基地局に伝送することもできる。

All of the information can also be transmitted to the serving base station.

  As another method for transmitting noise and interference dispersion information, the terminal may limit and / or recommend PMI for a cell that performs CoMP operation, and noise and interference dispersion value for the remaining cells that do not perform CoMP operation.

に加えて、特定ＣｏＭＰ隣接セルに対して制限または推奨するＰＭＩが適用された時における全体雑音及び干渉分散値

In addition, the total noise and interference dispersion value when PMI restricted or recommended for a specific CoMP neighboring cell is applied

または該

Or the

と特定ＣｏＭＰ隣接セルに対して制限または推奨するＰＭＩが適用する前のＣｏＭＰ動作を行う全体セルに対する雑音及び干渉分散値との差値である

And the noise and interference variance values for the whole cell performing CoMP operation before PMI that is restricted or recommended for a specific CoMP neighbor cell is applied

をサービング基地局に伝送することができる。すなわち、端末は、

Can be transmitted to the serving base station. That is, the terminal

値を追加的にサービング基地局に伝送することができる。ここで、

The value can additionally be transmitted to the serving base station. here,

値は、特定ＣｏＭＰ隣接セルに限定された雑音及び干渉分散値ではなく、端末に影響を及ぼす全体セルに対する雑音及び干渉分散値の変化量を意味する。

The value is not the noise and interference variance value limited to a specific CoMP neighbor cell, but means the amount of change in noise and interference variance value for the whole cell that affects the terminal.

  As another method of transmitting information on noise and interference dispersion information, the terminal may restrict and / or recommend a PMI, serving cell noise, and interference dispersion value for a cell performing CoMP operation.

及びＣｏＭＰ動作を行わない残りのセルに対する雑音及び干渉分散値

And interference and dispersion values for the remaining cells not performing CoMP operation

に加えて、

In addition to,

をサービング基地局に伝送することができる。または、端末は、特定ＣｏＭＰ隣接セルに対して制限及び／または推奨するＰＭＩ情報とＣＩＮＲ値である

Can be transmitted to the serving base station. Alternatively, the terminal has PMI information and CINR values that are restricted and / or recommended for a specific CoMP neighboring cell.

を伝送することができる。これを受信した基地局は、協力スケジューリング／ビームフォーミングを行う時に、ＰＭＩ情報、

Can be transmitted. The base station that has received this receives PMI information, when performing cooperative scheduling / beamforming.

値に基づいて

Based on value

のようにＣＩＮＲを計算することができる。ジョイントプロセシングを行う時は、

CINR can be calculated as follows. When doing joint processing,

のようにＣＩＮＲを計算することができる。このような伝送方法によって、端末はサービング基地局に伝送するフィードバック情報量を減少させることができる。また、端末が制限または／及び推奨するＰＭＩが適用された時と適用されなかった時における雑音及び干渉分散変化量

CINR can be calculated as follows. With such a transmission method, the terminal can reduce the amount of feedback information transmitted to the serving base station. In addition, the amount of change in noise and interference variance when the terminal's restricted or / and recommended PMI is applied or not applied

を用いてサービング基地局にＣＩＮＲ値を送ることもできる。すなわち、端末は、制限及び／または推奨するＰＭＩ、

Can be used to send the CINR value to the serving base station. That is, the terminal can restrict and / or recommend PMI,

をサービング基地局に伝送することができる。または、端末が制限または／及び推奨するＰＭＩ、

Can be transmitted to the serving base station. Or PMI restricted or / and recommended by the terminal,

をサービング基地局に伝送することができる。

Can be transmitted to the serving base station.

  Still another noise and interference dispersion information transmission method (Option 6) is a CQI value that a terminal transmits to a base station in a single cell operation.

に基づき、ＣｏＭＰ動作を行うＣｏＭＰ隣接セルに関する情報を追加的に伝送することもできる。すなわち、端末は、ＣｏＭＰ動作を行う隣接セルに対する干渉レベル情報を追加的にサービング基地局に伝送することができる。端末が多重セルの信号強度を測定する時、サービングセルと隣接セル間に参照シンボルリソース要素とデータリソース要素との衝突などにより、ＣｏＭＰ動作を行わない隣接セルに対する雑音及び干渉分散値に該当する値を測定して求めることが困難な場合がある。したがって、単一セル動作においてフィードバック情報伝送のために測定した値をそのまま用いて、多重セルにおいてＣｏＭＰ動作時にフィードバック伝送をすることによって、多重セルベースに拡張することができ、より効率的にフィードバック情報を伝送することができる。その結果、多重セルの下で、ＣｏＭＰ隣接セルに対する干渉レベル測定に伴うオーバーヘッド、フィードバック情報伝送に伴うオーバーヘッドを相当低減できる。

Based on the above, it is also possible to additionally transmit information related to the CoMP neighboring cell performing the CoMP operation. That is, the terminal can additionally transmit interference level information for neighboring cells performing CoMP operation to the serving base station. When the UE measures the signal strength of multiple cells, the value corresponding to the noise and interference variance value for the neighboring cell that does not perform CoMP operation due to the collision between the reference symbol resource element and the data resource element between the serving cell and the neighboring cell is determined. It may be difficult to determine by measurement. Therefore, by using the value measured for feedback information transmission in single cell operation as it is and performing feedback transmission at the time of CoMP operation in multiple cells, it can be extended to multiple cell base, and feedback information can be more efficiently performed. Can be transmitted. As a result, it is possible to considerably reduce overhead associated with interference level measurement for CoMP neighboring cells and overhead associated with transmission of feedback information under multiple cells.

  For example, the terminal is a CQI value for the serving cell under a single cell

値に、サービングセルの信号の強度に正規化した隣接セルの信号の強度

Neighbor cell signal strength normalized to serving cell signal strength

をさらに伝送することができる。これにより、協力スケジューリング／ビームフォーミング（ＣＳ／ＣＢ）方式だけでなく、ジョイントプロセシング（ＪＰ）方式も円滑に行うことができる。

Can be further transmitted. Thereby, not only the cooperative scheduling / beamforming (CS / CB) method but also the joint processing (JP) method can be performed smoothly.

  The noise and interference dispersion information transmission method described above is merely an example. The terminal can combine the noise and interference dispersion information in various forms, and feed back the measured channel state information in various forms to the serving base station.

  Table 1 below is a table illustrating measurement information values measured from neighboring cells in order for the terminal to transmit to the serving base station.

上記の表１に示す測定情報伝送は、例示的なものに過ぎず、端末は、測定した各種測定値を様々な形態に組み合わせてサービング基地局にフィードバックすることができる。

The measurement information transmission shown in Table 1 above is merely exemplary, and the terminal can combine the various measured values measured in various forms and feed back to the serving base station.

  FIG. 3 is a diagram for explaining a concept in which a terminal and a base station according to the present invention perform a CoMP operation.

There are a total of 9 neighboring cells (cell A to cell I) in a terminal located at a cell boundary, and 3 neighboring cells (cell A, cell B, cell C) are cooperative scheduling / beamforming or Suppose you are involved in PMI restrictions and / or recommendations. The terminal at the cell boundary belonging to the cell A receives interference from the cell B and the cell C, respectively, and wishes to limit W ₂ and W ₃ of the PMI to the cell B and the cell C, respectively. Assume a case. Here, the noise and interference variance values generated in the remaining 6 cells (cell D to cell I) that do not perform CoMP operation are:

と表現可能である。端末が、セルＢに対して制限したいＰＭＩであるＷ_２を伝送しようとする時、セルＢがＷ_２を制限した時の雑音及び干渉分散値である

Can be expressed. Terminal, when attempting to transmit a W ₂ is a PMI to be restricted to the cell B, is the noise and interference variance value when the cell B has limited W ₂

を共に伝送することができる。または、端末は、サービング基地局にセルＢがＷ_２を制限しなかった時における雑音及び干渉分散値と制限した時における値との差値である

Can be transmitted together. Or, the terminal is a difference value between the values at the time of limiting the noise and interference variance value at the time when the cell B does not limit W ₂ to the serving base station

をさらに送ることもできる。この時、セルＢに制限ＰＭＩが適用された時における雑音及び干渉分散値は

Can also be sent. At this time, the noise and interference variance values when the restricted PMI is applied to the cell B are

と、推奨ＰＭＩが適用された時における雑音及び干渉分散値は

And the noise and interference variance values when the recommended PMI is applied

と表すことができ、それらの差値は

And the difference between them is

と表すことができる。また、セルＢに制限または推奨ＰＭＩが適用された時における全体セル（セルＡ乃至セルＩ）の雑音及び干渉分散値の変化量を

It can be expressed as. In addition, when the restricted or recommended PMI is applied to the cell B, the amount of change in the noise and interference dispersion value of the entire cell (cell A to cell I)

と表すことができる。

It can be expressed as.

The terminal can transmit the measurement values in various forms to the serving base station in various combinations along with the PMI information. For example, the terminal, noise and interference variance value generated in the remaining six cells is not performed W ₂ and CoMP operation is PMI to be restricted to the cell B

に加えて、セルＢがＷ_２を制限した時における雑音及び干渉分散値

In addition to the noise and interference variance values when cell B limits W ₂

及び／または制限ＰＭＩによる雑音及び干渉分散値の変化量である

And / or the amount of change in noise and interference variance due to restricted PMI

をさらに含めてサービング基地局に伝送することができる。また、端末は、セルＢに対して制限しようとするＰＭＩであるＷ_２、及び

Can be transmitted to the serving base station. In addition, the terminal W ₂ that is PMI to be restricted to the cell B, and

の中から一つ以上の値を選択して共にサービング基地局に伝送することができる。

One or more values can be selected from among them and transmitted to the serving base station together.

Similarly, when the cell C, terminal, noise and interference variance value generated in the remaining six cells is not performed W ₃ and CoMP operation is PMI to be restricted to the cell C

に加えて、セルＣがＷ_３を制限した時における雑音及び干渉分散値

In addition to the noise and interference variance values when cell C limits W ₃

または制限ＰＭＩであるＷ_３による雑音及び干渉分散値の変化量である

Is the amount of change in the noise and interference variance values by W ₃ or restricted PMI

を伝送することができる。また、端末は、セルＣに対して制限しようとするＰＭＩであるＷ_３、及び

Can be transmitted. Further, the terminal W ₃ that is a PMI to be restricted to the cell C, and

の中から一つ以上の値を選択して共にサービング基地局に伝送することができる。

One or more values can be selected from among them and transmitted to the serving base station together.

  The base station receiving such information has a difference value between when the PMI to be limited and / or recommended based on the noise and interference dispersion value is applied in the neighboring cell and when it is not applied.

を求めることができ、これは、ＰＭＩ順位決定における問題を解決し、効率的な協力スケジューリング／ビームフォーミング動作を可能にする。

Which solves the problem in PMI ranking determination and enables efficient cooperative scheduling / beamforming operations.

  When the terminal transmits the CSI feedback information to the serving base station, the CSI feedback information can be normalized and transmitted.

  The terminal may report recommended transmission characteristics (eg, CQI, PMI, RI) and other channel state information (CSI) to the serving base station. In general, the CSI feedback system includes a quantized CSI feedback system and an analog CSI feedback system. Regardless of the type of CSI feedback scheme, the CSI reported by the UE to the serving cell is a spatial channel matrix H (hereinafter abbreviated as “channel matrix H” or “matrix H”) or spatial channel covariance. A matrix R (hereinafter abbreviated as “covariance matrix R” or “matrix R” or the like) may be included. That is, the terminal can transmit the spatial channel matrix H or the spatial channel covariance matrix R information as CSI feedback information to the serving base station. In addition to the spatial channel matrix H or the spatial channel covariance matrix R information, the terminal can transmit noise variance information (for example, , Interference level) can be further transmitted. That is, the terminal can transmit noise and interference dispersion to the serving base station together with the spatial channel matrix H or the spatial channel covariance matrix R value.

  In this way, the terminal can normalize and transmit the CSI in order to transmit the CSI more accurately and efficiently. This normalization method can be performed for each component of the channel matrix H and / or the covariance matrix R, and can also be performed for a column-based vector. Hereinafter, vector normalization in units of columns will be described.

  Normalization in vector units can be performed using the maximum value among the norm values of each column of the matrix. Not only the channel matrix H and / or covariance matrix R but also the noise and interference variance can be normalized using the column with the largest norm value. After normalization, each column can be transmitted in two ways.

  First, the terminal may send a weight factor of each column norm value weighted together with the CSI feedback information to the serving base station. The base station and the terminal share a codebook corresponding to one norm value (for example, norm = 1), and the serving base station receives phase information from the channel matrix H and / or covariance matrix R received from the terminal. (Phase information) can be obtained, and the size on the constellation is known from the weighting factor of the norm value of each column received from the terminal. As such a weight coefficient value, a unique value may be transmitted as it is, or may be transmitted in units of values quantized in advance. Further, it can be expressed only by the amount of change of the corresponding value with reference to the weighting factor 1.

  Second, the base station and the terminal have a codebook corresponding to a plurality of norm values in advance. From the channel matrix H and / or covariance matrix R transmitted by the terminal, not only the phase information but also the constellation The above size information can also be obtained. The greater the number of pre-defined codebooks, the more accurate estimation is possible.

  A case where the terminal described above transmits the normalized channel matrix H and / or covariance matrix R will be described with an example. Suppose a 4 × 4 MIMO system with four base station transmit antennas and four terminal receive antennas. The terminal can transmit a 4 × 4 channel matrix H expressed as Equation 1 below to the serving base station.

ここで、各列のノルム値をそれぞれ

Where the norm value of each column is

としよう。チャネル行列Ｈは、行列の各列のノルム値のうち最大値である１番目の列におけるノルム値である２で正規化できる。このように正規化された各列のノルム値はそれぞれ、１、０．５、０．５、０．２５になり、端末は、１以外のノルム値に対する重み係数をサービング基地局に伝達することができる。

Let's try. The channel matrix H can be normalized by 2 which is the norm value in the first column which is the maximum value among the norm values in each column of the matrix. The norm values of the columns normalized in this way are 1, 0.5, 0.5, and 0.25, respectively, and the terminal transmits a weighting factor for norm values other than 1 to the serving base station. Can do.

  In addition to the method in which the terminal transmits the weighting factor to the serving base station, the terminal and the base station have codebooks corresponding to various norm values in advance, and channel matrix values can also be obtained by mapping the corresponding values. I understand. For example,

のように、４つのノルム値に対するコードブックがあるとしよう。まず、チャネル行列Ｈを列のノルム値のうち最大のノルム値で正規化を行うことができる。上記の数学式１の例において、正規化後の１番目の列は、

Suppose we have a codebook for four norm values. First, the channel matrix H can be normalized with the maximum norm value of the column norm values. In the example of Equation 1 above, the first column after normalization is

のうちのいずれかの値にマッピングされ、２、３番目の列はそれぞれ、

Are mapped to any of the values in the second and third columns, respectively.

のうちのいずれかの値にそれぞれマッピングされてよい。同様に、４番目の列は、

May be mapped to any one of the values. Similarly, the fourth column is

のうちのいずれかの値にマッピングされてよい。マッピング後には、端末は、該当のインデックスをサービング基地局にフィードバックすることができる。

May be mapped to any of the values. After the mapping, the UE can feed back the corresponding index to the serving base station.

  The present invention can be extended to the transmission of the channel matrix H or covariance matrix R of each of a number of base stations and the noise and interference variance values of other base stations. Here, normalization can be performed using the maximum norm value of columns in all channel matrices or the maximum norm value of columns in all covariance matrices.

  FIG. 4 is a block diagram showing a preferred embodiment of the terminal device according to the present invention.

  Referring to FIG. 4, a terminal device capable of executing a CoMP operation in a wireless communication system includes a processor 410, a memory unit 420, a transmission module 430, and a reception module 440.

  The processor 410 includes a measurement module 411. The measurement module 411 can measure the interference level, noise, and interference dispersion value using reference signals received from one or more neighboring cells.

  The memory unit 420 can store various types of information received from the base station and values measured by the measurement module 411 for a predetermined period. The memory unit 420 may replace other components such as a buffer (not shown).

  The transmission module 430 can transmit the interference level information or noise and interference dispersion information measured by the measurement module 411 and PMI information to be restricted or recommended for a specific neighboring cell performing CoMP operation to the serving base station. .

  The receiving module 440 receives various signals and data such as control information and data from a serving base station or the like.

  The detailed description of the preferred embodiments of the present invention disclosed above is provided to enable any person skilled in the art to implement and practice the present invention. Although the present invention has been described with reference to the preferred embodiments, it is understood that various modifications and changes can be made to the present invention without departing from the scope of the present invention by those skilled in the art. Can understand. For example, those skilled in the art can use the configurations described in the above embodiments in a combination manner.

  Accordingly, the present invention is not limited to the embodiments disclosed herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (16)

A method in which a terminal transmits feedback information in a wireless communication system in which one or more base stations perform CoMP (Coordinated Multi-Point) operation,
PMI (Precoding Matrix Index) set information to be restricted or recommended for a specific neighboring cell performing the CoMP operation is transmitted to the serving base station,
The difference between the PMI set applied to the calculated signal strength level or interference level and the PMI set signal strength is calculated when the information was not the applicability or interference level for the particular neighboring cell Transmitting a signal strength gain value or an interference level gain value, which is a corresponding value, to the serving base station;
A CoMP feedback information transmission method.   The signal strength or interference level includes a signal-to-interference plus noise ratio (SINR) value, a reference signal received power (RSRP), a reference signal received quality (RSRQ), and a reference signal received quality (RSRQ). ), A reference signal strength indicator (RSSI: Reference Signal Strength Indicator), a PD (Propagation Delay), and a carrier-to-interference plus noise ratio (CINR) value. The CoMP feedback according to claim 1. Information transmission method. A method in which a terminal transmits feedback information in a wireless communication system that performs CoMP (Coordinated Multi-Point) operation,
Measure noise and interference variance values corresponding to signal strength or interference level using reference signals received from one or more neighboring cells,
Transmitting noise and interference dispersion information including the measured noise and interference dispersion value, and PMI (Precoding Matrix Index) information desired to be restricted or recommended for a specific neighboring cell performing the CoMP operation to a serving base station; A CoMP feedback information transmission method.   The noise and interference variance information includes noise and interference variance values when PMI that is desired to be restricted or recommended for specific neighboring cells performing the CoMP operation is applied, and noise and interference variance values when the PMI is not applied. The CoMP feedback information transmission method according to claim 3, comprising first noise corresponding to the difference value and interference dispersion information.   The method of claim 3, wherein the noise and interference dispersion information further includes second noise and interference dispersion information corresponding to noise and interference dispersion values for a cell that does not perform the CoMP operation. The noise and interference variance information further includes a third noise and interference variance information corresponding to the Japanese Teitonari the restriction or suggested value calculated by applying the PMI information to contact the cell, according to claim 5 CoMP feedback information transmission method. The noise and interference variance information corresponds to the difference between the noise and interference variance values before application of the restriction or suggested PMI information to the Japanese Teitonari contact cell, a noise and interference variance value when applied The CoMP feedback information transmission method according to claim 5, further comprising fourth noise and interference dispersion information which are values. The noise and interference variance information, the Japanese Teitonari and noise and interference variance value calculated by applying the PMI to be the limit for contact cell, the recommended want PMI applied to the calculated noise and interference variance The CoMP feedback information transmission method according to claim 5, further comprising fifth noise and interference dispersion information corresponding to the value. The noise and interference variance information, and the Japanese Teitonari noise and interference variance value calculated by applying the PMI to be recommended as the noise and interference variance value calculated by applying a PMI to be restricted for contact cell The CoMP feedback information transmission method according to claim 5, further comprising sixth noise and interference dispersion information which are values corresponding to the difference.   The noise and interference variance information further includes seventh noise and interference variance information corresponding to noise and interference variance values calculated by applying PMI information restricted or recommended for the entire cell performing the CoMP operation. The CoMP feedback information transmission method according to claim 5. The noise and interference variance information, the before applying the PMI said received against Japanese Teitonari contact cell, wherein a noise and interference variance value for the entire cell to be CoMP operation, the noise is calculated by applying and The CoMP feedback information transmission method according to claim 5, further comprising eighth noise and dispersion information that are values corresponding to a difference from the interference dispersion value.   The CoMP feedback information transmission method according to claim 5, wherein the noise and interference dispersion information further includes noise and dispersion value information for a serving cell. The noise and interference variance information, as well as noise and variance values for said serving cell, wherein the restriction or suggested applying the PMI information the noise and interference variance values for CoMP does not operate cells, or the Japanese Teitonari contact cell The CoMP feedback information transmission method according to claim 12, further comprising information on a value expressed using the noise and interference dispersion value calculated in the above. The noise and interference variance information, said with noise and variance values for the serving cell, the noise and interference variance values for CoMP does not operate cells, or before application of the received PMI in the Japanese Teitonari contact cell noise and The CoMP feedback information transmission method according to claim 12, further comprising information of a value expressed using a value corresponding to a difference between the variance value and the noise calculated by applying the variance value and the variance value. A method in which a base station performs a CoMP operation in a wireless communication system,
Noise and interference variance information including strength or interference level of a signal to the to the base station ends late in wishes to limit or recommended PMI (Precoding Matrix Index) information, and one or more neighboring cells measured by the terminal Receive
Determining an order of PMIs to limit or recommend to the terminal based on the received PMI information and the noise and interference variance information;
A CoMP operation method including: A terminal device that transmits feedback information in a wireless communication system that performs CoMP (Coordinated Multi-Point) operation,
A measurement module for measuring noise and interference variance including signal strength or interference level using reference signals received from one or more neighboring cells;
A transmission module for transmitting noise and interference dispersion information including the measured noise and interference dispersion value, and PMI (Precoding Matrix Index) information to be restricted or recommended for a specific neighboring cell performing the CoMP operation to a serving base station; ,
Including a terminal device.

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