KR20150123105A - Method and Device for Aperiodic CSI Report in Wireless System - Google Patents

Abstract

The present invention relates to a method and device for reporting aperiodic channel status information in a mobile communications system. The present invention relates to a method and device for reporting and indicating channel status information of a base station in a mobile communications system. The method comprises the steps of: determining whether it is needed to report aperiodic channel status information for multi-user-based channel status information (MU-CSI) report of a terminal; and transferring MU-CSI report trigger information and the aperiodic channel state information report indicator to the terminal when needed.

Description

TECHNICAL FIELD The present invention relates to a method and apparatus for reporting non-periodic channel state information in a mobile communication system,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless communication system, and more particularly, to a method and apparatus for reporting an aperiodic channel state information in a mobile communication system that performs multiple input / multiple output (MIMO) Lt; / RTI >

The mobile communication system has evolved into a high-speed and high-quality wireless packet data communication system for providing data service and multimedia service apart from providing initial voice-oriented service. In recent years, HSDPA (High Speed Downlink Packet Access), HSUPA (Long Term Evolution), LTE (Long Term Evolution - Advanced), and 3GPP2 (High Generation Partnership Project) Rate Packet Data) and IEEE (Institute of Electrical and Electronics Engineers) 802.16 have been developed to support high-speed, high-quality wireless packet data transmission service. In particular, LTE system is developed to efficiently support high - speed wireless packet data transmission and maximizes wireless system capacity by utilizing various wireless connection technologies. The LTE-A system is an advanced wireless system in LTE systems and has improved data transmission capabilities compared to LTE.

The LTE refers to a base station and a terminal equipment corresponding to a release 8 or 9 of the 3GPP standards body, and the LTE-A refers to a base station and a terminal equipment corresponding to Release 10 of the 3GPP standards body. The 3GPP standards body is based on the standardization of the LTE-A system and is proceeding with the standardization of the subsequent release with improved performance.

Existing 3G and 4G wireless packet data communication systems such as HSDPA, HSUPA, HRPD and LTE / LTE-A have been developed to improve transmission efficiency by using Adaptive Modulation and Coding AMC method and a channel-sensitive scheduling method. With the AMC method, the transmitter can adjust the amount of data to be transmitted according to the channel state. In other words, if the channel state is not good, the amount of data to be transmitted is reduced so that the probability of receiving error is adjusted to a desired level. If the channel state is good, the amount of data to be transmitted is increased so that the probability of receiving error can be effectively transmitted. Using the above-described channel-responsive scheduling resource management method, the transmitter selectively services a user having a good channel state among a plurality of users, thereby increasing the system capacity as compared to providing a channel to a user and providing a service. This increase in capacity is called a so-called multi-user diversity gain. In other words, the AMC method and the channel-responsive scheduling method are based on feedback of partial channel state information from a receiver and apply a proper modulation and coding scheme to a time point determined to be the most efficient.

The AMC method may also include a function of determining the number or rank of spatial layers of a signal to be transmitted when used with the MIMO transmission scheme. In this case, the AMC method considers only how many layers are to be transmitted using MIMO without considering coding rate and modulation scheme, in order to determine the optimum data rate.

Recently, studies have been actively conducted to convert Code Division Multiple Access (CDMA), which is a multiple access scheme used in second and third generation mobile communication systems, into OFDMA (Orthogonal Frequency Division Multiple Access) in the next generation system. 3GPP and 3GPP2 have begun to standardize on evolutionary systems using OFDMA. It is known that the capacity increase can be expected in the OFDMA system as compared with the CDMA system. One of the various causes of capacity increase in the OFDMA scheme is that frequency domain scheduling can be performed on the frequency axis. As the channel gains the capacity gain by the channel adaptive scheduling method according to the time varying characteristics, the channel gain the capacity gain by using different characteristics according to the frequency.

1 is a diagram illustrating time and frequency resources in an LTE / LTE-A system.

Referring to FIG. 1, a radio resource transmitted from a base station (eNB) to a user equipment (UE) is divided into resource blocks (RBs) on the frequency axis and subframes Divided.

The RB is generally composed of 12 subcarriers in the LTE / LTE-A system and occupies a band of 180 kHz. In a LTE / LTE-A system, a subframe is generally composed of 14 OFDM symbols and occupies a time interval of 1 msec. In the scheduling, the LTE / LTE-A system can allocate resources in units of subframes in the time axis and resources in units of RBs in the frequency axis.

2 is a diagram illustrating radio resources of 1 subframe and 1 RB, which are the minimum units that can be downlink-scheduled in the LTE / LTE-A system.

The radio resources shown in FIG. 2 are composed of one subframe on the time axis and one RB on the frequency axis. The radio resource is composed of 12 subcarriers in the frequency domain and 14 OFDM symbols in the time domain, thereby providing a total of 168 unique frequency and time positions. In LTE / LTE-A, the respective natural frequencies and time positions in FIG. 2 are referred to as RE (resource elements).

A plurality of different types of signals may be transmitted to the radio resource shown in FIG.

One. CRS (Cell Specific Reference Signal): A reference signal transmitted for all terminals belonging to one cell

2. DMRS (Demodulation Reference Signal): This is a reference signal transmitted for a specific UE and is used to perform channel estimation to recover information contained in a PDSCH (Physical Downlink Shared Channel). One DMRS port is transmitted with the same precoding as the PDSCH layer connected thereto. A terminal desiring to receive a specific layer of the PDSCH receives the DMRS port connected to the layer, performs channel estimation, and restores information on the layer using the channel estimation.

3. PDSCH (Physical Downlink Shared Channel): A data channel transmitted in the downlink and used by a base station to transmit traffic to a mobile station. In the data region of FIG. 2, a reference signal Sent using a non-transmitted RE

4. CSI-RS (Channel Status Information Reference Signal): A reference signal transmitted for terminals belonging to one cell and used for measuring the channel status. A plurality of CSI-RSs can be transmitted to one cell.

5. ZP-CSI-RS: The actual signal is not transmitted at the position where the CSI-RS is transmitted.

6. IMR (Interference Measurement Resource): It corresponds to the location where CSI-RS is transmitted, and one or more of A, B, C, D, E, F, G, H, . The UE assumes that all signals received in the REs set in the IMR are interference and perform interference measurement.

7. Other Control Channels (PHICH, Physical Control Format Indicator Channel (PCFICH), Physical Downlink Control Channel (PDCCH)): Provides the control information necessary for the terminal to receive the PDSCH or uplink data ACK / NACK transmission for hybrid automatic repeat request (HARQ) transmission

In the LTE-A system in addition to the above-mentioned signal, zero power CSI-RS can be set so that CSI-RS transmitted by different base stations can be received without interference to the terminals of the corresponding cell. The zero power CSI-RS (muting) can be applied at a position where the CSI-RS can be transmitted. Generally, the UE receives a traffic signal by skipping the radio resource. In LTE-A systems, zero power CSI-RS (muting) is also referred to as muting in another term. zero power CSI-RS (muting) is applied to the location of the CSI-RS and the transmission power is not transmitted.

In FIG. 2, the CSI-RS is transmitted using a part of the positions indicated by A, B, C, D, E, E, F, G, H, I and J according to the number of antennas transmitting CSI- . The zero power CSI-RS (muting) can also be applied to a portion of the locations indicated by A, B, C, D, E, E, F, G, H, I, In particular, the CSI-RS can be transmitted in 2, 4, or 8 REs depending on the number of antenna ports to transmit. When the number of antenna ports is two, the CSI-RS is transmitted in half of the specific pattern in FIG. 2. When the number of antenna ports is four, the CSI-RS is transmitted to all the specific patterns. When the number of antenna ports is eight, CSI-RS is transmitted. On the other hand, in case of zero power CSI-RS (muting), it is always done in one pattern unit. That is, the zero power CSI-RS (muting) can be applied to a plurality of patterns but can not be applied to only a part of one pattern when the positions do not overlap with the CSI-RS. However, it can be applied only to a part of one pattern only when the positions of the CSI-RS and the zero power CSI-RS (muting) are overlapped.

2, A, B, C, D, E, F, G, H, I, and J may be set to IMR, respectively. When an IMR is set for a specific UE, the UE assumes that a signal received from the REs belonging to the set IMR is an interference signal. The purpose of the IMR is to enable the terminal to measure the strength of the interference. That is, the UE measures the strength of a signal received from the REs belonging to the IMR set in the UE, and determines the strength of the interference.

3 is a diagram illustrating radio resources transmitted from two base stations in order to explain the operation principle of the IMR.

Referring to FIG. 3, the base station A sets the IMR C in RE of a radio resource to be transmitted to a terminal located in a cell A. Further, the base station B sets IMR J to the RE of the radio resource to be transmitted to the terminal located in the cell B.

the UEs located in the cell A receive the PDSCH transmitted from the base station A and the channel state information must be notified to the base station A. [ The terminal must be able to measure Es / (Io + No) (Energy of Signal (Es) vs. Interference (Io) and Noise (No) strength) of the channel to generate the channel state information do. The IMR is intended to enable a terminal to measure interference and noise intensity.

In FIG. 3, when the base station A and the base station B transmit at the same time, they generate interference with each other. That is, the signal transmitted from the base station B acts as an interference to the terminal receiving the signal from the base station A. Also, the signal transmitted from the base station A acts as interference to the terminal receiving the signal from the base station B.

In FIG. 3, the base station A sets the IMR C to the corresponding terminal so that the terminal located in the cell A measures the interference generated by the base station B. Also, base station A does not transmit signals at the location of IMR C. As a result, the signal received by the terminal in the IMR C is a signal transmitted from the base station B (300, 310). That is, the terminal receives only the signal transmitted from the base station B in the IMR C and measures the reception strength The strength of the interference occurring in the base station B can be determined. Similarly, the base station B sets the IMR J to the corresponding terminal so that the terminal located in the cell B measures the interference generated by the base station A. Also, base station B does not transmit signals at the location of IMR J. As a result, the signal received by the terminal at the IMR J is the signal transmitted from the base station A. (320, 330)

As shown in FIG. 3, when the IMR is used, it is possible to effectively measure the strength of interference generated at other base stations or transmission points. That is, in a multi-cell mobile communication system or a distributed antenna system in which a plurality of cells coexist, the strength of interference generated in a neighboring cell or the interference generated in a neighboring transmission point The strength can be measured effectively. On the other hand, interference that can not be effectively measured by such an IMR is the strength of MU-MIMO (Multi User-Multiple Input Multiple Output) interference.

In order to facilitate communication between the base station and the terminal, the terminal measures the channel and interference and reports it to the base station. This report is called a Channel State Information Report (CSI Report). The UE estimates the interference with the downlink channel through the CSI-RS and the IMR, and generates a rank indicator, a channel quality indicator (CQI), and a precoding matrix indicator (PMI) And performs feedback to the base station. Periodic feedback through the physical uplink control channel (PUCCH) of the terminal is made in the following four modes:

Mode 1-0: RI, wideband CQI (wCQI)

Mode 1-1: RI, wCQI, broadband PMI (wPMI)

Mode 2-0: RI, wCQI, subband CQI (sCQI)

Mode 2-1: RI, wCQI, wPMI, sCQI, sPMI

The feedback timing of each information for the four feedback modes is determined by the values of N _pd , N _{OFFSET, CQI} , M _RI , and N _{OFFSET, RI,} etc. transmitted to the higher layer signal. In the feedback mode 1-0, the transmission period of the wCQI is N _pd, and the feedback timing is determined with the sub-frame offset value of N _{OFFSET and CQI} . Also, the transmission period of RI is N _pd · M _RI and the offsets are N _{OFFSET, CQI} + N _{OFFSET, RI} . FIG. 3 shows the feedback timing of RI and wCQI in the case of N _pd = 2, M _RI = 2, N _{OFFSET, CQI} = 1, N _{OFFSET, and RI} = -1. Here, each timing represents a subframe index. Feedback Mode 1-1 has the same feedback timing as Mode 1 - 0 but has a difference that PMI is transmitted together at wCQI transmission timing.

In feedback mode 2-0, the feedback period for subband channel quality indicator (sCQI) is N _pd and the offset value is N _{OFFSET, CQI} . The feedback period for the wideband channel quality indicator (wCQI) is H · N _pd, and the offset value is N _{OFFSET, CQI} as the offset value of sCQI. Where H = J · K + 1, where K is the upper signal and J is the value determined by the system bandwidth. For example, the J value for a 10 MHz system is defined as 3. As a result, the wCQI is transmitted once every once for every H scCI transmissions. And the period of _RI is M _RI · H · N _pd and the offsets are N _{OFFSET, CQI} + N _{OFFSET, RI} . 4 shows RI, sCQI, and wCQI feedback timings for N _pd = 2, M _RI = 2, J = 3 (10 MHz), K = 1, N _{OFFSET, CQI} = 1, N _OFFSET, . Feedback Mode 2-1 has the same feedback timing as Mode 2-0, but PMI is transmitted together at the wCQI transmission timing.

The feedback timing described above is a case where the number of CSI-RS antenna ports is four or less, and two PMI information are fed back to eight CSI-RS antenna port numbers unlike the above case. For the eight CSI-RS antenna ports, the feedback mode 1-1 is again divided into two submodes. In the first submode, the RI is transmitted with the first PMI information and the second PMI information is transmitted with the wCQI. Here, the feedback period and the offset for the wCQI and the second PMI are defined as N _pd , N _{OFFSET and CQI} , and the feedback period and the offset value for the RI and the first PMI information are M _RI N _pd and N _{OFFSET, CQI} + N _{OFFSET , And RI} .

The feedback mode 2-1 for eight CSI-RS antenna ports adds a precoding type indicator (PTI), the PTI is fed back with _RI , the period is M _RI H N _pd , the offsets are N _{OFFSET, CQI} + N _{OFFSET, RI are} defined. If the PTI is 0, the first PMI, the second PMI, and the wCQI are fed back, and the wCQI and the second PMI are transmitted together at the same timing, the period is N _pd, and the offset is given as N _{OFFSET, CQI} . Also, the period of the first PMI is H '· N _pd, and the offset is N _{OFFSET, CQI} . Here, H 'is transmitted as an upper signal. On the other hand, if the PTI is 1, the PTI is transmitted with the RI, the wCQI and the second PMI are transmitted together, and the sCQI is further fed back. In this case, the first PMI is not transmitted. The period and offset of the PTI and RI are the same as when the PTI is 0, and the sCQI is defined as the N _{OFFSET, CQI} with the period N _pd offset. Also, the wCQI and the second PMI are fed back with the period of H · N _{pd ,} the offset of N _{OFFSET, and CQI} , and H is defined as when the number of CSI-RS antenna ports is four. 5 and 6 are _graphs for N _pd = 2, M _RI = 2, J = 3 (10 MHz), K = 1, H '= 3, N _{OFFSET, CQI} = 1, N _OFFSET, Indicates the feedback timing when PTI = 0 and PTI = 1.

Also, the downlink channel information estimated through the CSI-RS may be transmitted from the UE to the BS through aperiodic feedback through a physical uplink shared channel (PUSCH). When a base station desires to acquire aperiodic feedback information of a specific UE, the Node B notifies the UE of an aperiodic feedback indicator (CSI) included in downlink control information (DCI) for uplink data scheduling of the UE request field) to perform aperiodic feedback and perform uplink data scheduling of the corresponding terminal. When the UE receives the indicator set to perform aperiodic feedback in the n subframe, the UE performs uplink transmission including the aperiodic feedback information in the data transmission in the n + k subframe. Where k is a parameter defined in the 3GPP LTE Release 10 standard, 4 for frequency division duplexing (FDD), and 1 for time division duplexing (TDD).

[Table 1]

Table 1 defines k values for each subframe number n in a time division duplexing (ULD) UL / DL configuration.

In LTE Release 11, the aperiodic feedback indicator is included in the uplink DCI format 0 or DCI format 4 and is defined as one or two bits. When the feedback indicator is one bit, if the aperiodic feedback indicator is set to ON, the UE transmits channel information on the "serving cell c " to the base station through PUSCH aperiodic feedback. Here, the meaning of a serving cell c means a downlink component carrier (CC) to which a DCI is transmitted in a carrier aggregation (CA) situation.

On the other hand, if the aperiodic feedback indicator is two bits, the UE performs aperiodic feedback in the manner defined in Tables 2a and 2b below.

[Table 2a]

[Table 2b]

Table 2a defines a method for performing aperiodic feedback on a two bit non-periodic feedback indicator (CSI Request Field) in Transmission Mode 10, Bit periodic feedback indicator (CSI Request Field).

The meaning of 'serving cell c' in Tables 2a and 2b is that the uplink CC indicated by the CIF (carrier indication field) included in the DCI for uplink scheduling, unlike the case where the non-periodic feedback indicator is one bit, And a linked downlink CC. That is, when the UE receives the aperiodic feedback indicator set to '01', the UE can transmit the feedback information of the DL CC linked thereto in the UL CC indicated by the CIF. On the other hand, if the UE receives the aperiodic feedback indicator set to '10' or '11', the UE transmits feedback information on the uplink CC set up to the uplink CC indicated by the CIF.

If the aperiodic feedback is set, the feedback information for each CC includes at least one of RI, PMI, or CQI according to the feedback setting as in the case of periodic feedback. And the CQI may include at least one of wCQI or sCQI have.

The LTE system supports multiple input multiple output (MIMO) transmission using multiple transmit and receive antennas. MIMO is a method of multiplexing information in a spatial manner according to an instantaneous channel generated in a plurality of transmitting and receiving antennas. Since the MIMO transmission can spatially multiplex and transmit a plurality of data streams to one time and frequency resource, the data transmission rate can be increased several times as compared with the existing non-MIMO transmission. LTE Release 11 supports MIMO transmission between up to 8 transmit antennas and up to 8 receive antennas. In this case, up to 8 data streams can be spatially multiplexed and transmitted, and the maximum data rate can be increased by 8 times compared with non-MIMO.

In general, MIMO is a single user-multiple-input multiple output (SU-MIMO) system that transmits a plurality of data streams spatially multiplexed to one terminal, and an MU-MIMO system that transmits a plurality of data streams spatially multiplexed to a plurality of terminals simultaneously. And MIMO (Multi User - Multiple Input Multiple Output). In SU-MIMO, a plurality of spatially multiplexed data streams are transmitted to one terminal, but in MU-MIMO, a plurality of spatially multiplexed data streams are transmitted to a plurality of terminals. In MU-MIMO, a base station transmits a plurality of data streams, and each terminal receives one or more data streams of a plurality of data streams transmitted by the base station. Such MU-MIMO is particularly useful when the transmission antenna of the base station is larger than the reception antenna of the terminal.

In order to transmit MU-MIMO, channel state information of UEs scheduled to use the same time and frequency resources should be grasped. As mentioned above, in MU-MIMO, signals are transmitted to a plurality of terminals using a plurality of spatially multiplexed data streams, and each signal acts as an interference to signals of other terminals. This interference is called MU-MIMO interference. This MU-MIMO interference depends on how the UEs are scheduled together with which UEs with which transmission method, and this is called MU hypothesis.

In the case where the UE can not accurately measure the MU-MIMO interference in determining the channel state information, the system performance is not optimized when the base station transmits the MU-MIMO transmission to a plurality of terminals including the corresponding terminal . The reason for getting unoptimized system performance is that the base station can not effectively perform link adaptation. The link adaptation refers to allocating a data rate according to the channel state of the UE. In a mobile communication system such as LTE, the link adaptation is performed based on channel state information transmitted from the UE. The problem is that when the UE fails to measure MU-MIMO interference, the channel state information notified to the base station is not suitable for transmitting MU-MIMO, and thus it is difficult to effectively perform link adaptation.

If the performance degradation occurs particularly because the influence of MU-MIMO interference is not reflected in the channel state information, MU-MIMO transmission is simultaneously performed to a plurality of UEs such as Massive MIMO or Full-Dimension MIMO (FD-MIMO) In the mobile communication system.

Massive MIMO or Full-Dimension MIMO has tens to hundreds of transmit antennas at the base station. In order to improve the system performance, the number of data streams that can be multiplexed must be significantly increased compared with the conventional LTE system. For this purpose, a mobile communication system supporting FD-MIMO must be able to simultaneously transmit to multiple terminals simultaneously using MU-MIMO.

4 is a diagram illustrating a base station supporting FD-MIMO.

Referring to FIG. 4, a base station may include a plurality of sets of transmit antennas 400, and may simultaneously transmit signals to a plurality of terminals through transmit antennas 410 (420, 430).

In FIG. 4, the plurality of transmit antennas may be a 2-D antenna array panel having a two-dimensional plane structure, and each antenna may correspond to a function of the length of the wavelength with other antennas, As shown in FIG. The base station transmits high order MU-MIMO (high dimensional multi-user MIMO) to a plurality of terminals using the 400 corresponding to the plurality of antenna sets. The high order MU-MIMO refers to a method of allocating transmission beams spatially separated to a plurality of terminals using a plurality of base station transmission antennas and transmitting data. Since the high order MU-MIMO is performed using the same time and frequency resources, there is an advantage that the performance of the system can be greatly improved.

However, the prior art does not take into consideration the situation of feedback based on various MU-MIMO interference occurring for various MU hypothesis mentioned above. When such a conventional feedback technique is applied, since the MU-MIMO interference can not be measured in the cyclic channel state information and the aperiodic channel state information, when the high order MU-MIMO is operated like the FD-MIMO system, have.

The embodiments of the present invention have been proposed in order to solve the above-mentioned problems. In the mobile communication system, the UE uses an aperiodic feedback indicator to detect interference of various multi-user multi- The present invention provides a method and apparatus for generating channel state information to be fed back in consideration of interference.

According to an aspect of the present invention, there is provided a method of reporting channel state information of a base station in a mobile communication system, the method comprising: receiving a multi-user channel status information report Determining whether non-periodic channel state information reporting for the CSI report is necessary; And transmitting the MU-CSI report trigger information and the aperiodic channel status information report indicator to the terminal, if necessary.

A method of reporting channel state information of a UE in a mobile communication system according to another embodiment of the present invention includes generating a multi-user channel status information report (MU-CSI report) Receiving an information reporting indicator; Measuring channel state using the MU-CSI report trigger information; And reporting the generated aperiodic channel state information to the base station based on the measured result.

A base station for reporting an aperiodic channel state information report in a mobile communication system according to another embodiment of the present invention includes a transmitter / receiver for transmitting / receiving signals to / from a terminal; CSI report trigger information and a non-periodic channel status information report for a multi-user channel status information report (MU-CSI report) And a controller for controlling delivery of the aperiodic channel status information report indicator to the terminal.

A terminal reporting channel state information in a mobile communication system according to another embodiment of the present invention includes a transmitting / receiving unit for transmitting / receiving signals to / from a base station; (MU-CSI report) trigger information and an aperiodic channel state information report indicator based on the MU-CSI report trigger information and a channel status information report And reporting the generated aperiodic channel state information to the base station based on the measured result.

According to the embodiment of the present invention, the UE uses the non-periodic feedback indicator transmitted from the base station to provide channel state information to be fed back in consideration of interference (Multi User - Multi Input Multi Output Interference) . By applying this feedback technology, high-order MU-MIMO such as FD-MIMO system can be smoothly operated, and the performance of the system can be greatly improved.

1 is a diagram illustrating time and frequency resources in an LTE / LTE-A system.
2 is a diagram illustrating radio resources of 1 subframe and 1 RB, which are the minimum units that can be downlink-scheduled in the LTE / LTE-A system.
3 is a diagram illustrating radio resources transmitted from two base stations in order to explain the operation principle of the IMR.
4 is a diagram illustrating a base station supporting FD-MIMO.
5 is a diagram illustrating a method for a BS to indicate an MU-CSI report to a UE according to an embodiment of the present invention.
6 is a diagram illustrating a method for a BS to indicate an MU-CSI report to a UE according to another embodiment of the present invention.
7 is a diagram illustrating a method for a BS to indicate an MU-CSI report to a UE according to another embodiment of the present invention.
8 is a diagram illustrating a method for a BS to indicate an MU-CSI report to a UE according to another embodiment of the present invention.
FIG. 9 is a diagram illustrating a method for the BS to indicate the MU-CSI report to the MS according to another embodiment of the present invention.
FIG. 10 is a diagram illustrating a method in which a base station indicates an MU-CSI report to a terminal when the PMI structure is a two-dimensional structure of i1 / i2 in the embodiment of FIG.
11 is a diagram illustrating a method for a BS to indicate an MU-CSI report to a UE according to another embodiment of the present invention.
FIG. 12 is a diagram illustrating a method of reporting an MU-PMI (Multi User-Precoding Matrix Indicator) together using the SU-PMI reference method 3 of FIG.
FIG. 13 is a diagram illustrating a method in which a base station indicates an MU-CSI report to a terminal according to another embodiment of the present invention, and the terminal reports an MU-CSI according to an instruction.
14 is a view for explaining an operation of a base station indicating a MU-CSI report to a terminal according to the present invention.
15 is a diagram illustrating an operation of a terminal reporting an MU-CSI to a base station according to the present invention.
16 is a view for explaining an operation of a base station indicating a MU-CSI report to a terminal according to another embodiment of the present invention.
17 is a diagram illustrating an operation of a terminal reporting an MU-CSI to a base station according to another embodiment of the present invention.
18 is a view for explaining an operation of a base station indicating a MU-CSI report to a terminal according to another embodiment of the present invention.
FIG. 19 is a diagram illustrating an operation of a terminal reporting an MU-CSI to a base station according to another embodiment of the present invention.
20 is a view for explaining an operation of a base station indicating an MU-CSI report to a terminal according to another embodiment of the present invention.
21 is a view for explaining an operation of a terminal reporting an MU-CSI to a base station according to another embodiment of the present invention.
22 is a block diagram illustrating an internal structure of a base station according to the present invention.
23 is a block diagram showing an internal structure of a terminal according to the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. 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 present invention as defined by the following claims and their equivalents. . Therefore, the definition should be based on the contents throughout this specification.

For the same reason, some of the components in the drawings are exaggerated, omitted, or schematically illustrated. Also, the size of each component does not entirely reflect the actual size. In the drawings, the same or corresponding components are denoted by the same reference numerals.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION In describing embodiments of the present invention in detail, an OFDM-based wireless communication system, particularly a 3GPP EUTRA standard, will be the main object, It is to be understood that the subject matter may be applied to other communication systems having similar technical background and channel form with slight modifications within the scope of the present invention without departing from the scope of the present invention, .

According to the present invention, data can be transmitted using MU-MIMO for a terminal existing in a cellular mobile communication system. In order for the MU-MIMO system to have sufficient performance, it is important to allow channels sufficient for spatial separation of channels between the base station and the terminals to be scheduled together and transmit / receive together. Therefore, feedback on the channel state information generated by assuming the UEs to be scheduled together is required, and when scheduling the UEs together using such information, the MU-MIMO system provides improved system performance compared to the existing mobile communication system .

In the present invention, when a UE generates channel state information for MU-MIMO, a method for reporting an aperiodic channel state information reporting method as a means for a base station to measure MU-MIMO interference on the assumption of various states is proposed do. In order to measure the MU-MIMO interference (MU-MIMO Interference) and feedback the channel state to the UE, the base station proposed in the present invention instructs the UE to perform various MU-CSI reports through an aperiodic feedback indicator (CSI request field) Is as follows.

MU-CSI report indication method 1: The MU-CSI report is instructed to the terminal together with the MU-PMI which the base station judges optimally

MU-CSI report Indication method 2: The MU-CSI report is instructed to the terminal along with the IMR corresponding to the interference condition desired by the base station

MU-CSI report Indication method 3: The base station instructs the terminal to transmit an MU-CSI report together with the interference PMI corresponding to the desired interference condition

In the MU-CSI report indication method proposed by the present invention, the MU-PMI (Indication Method 1), IMR (Indication Method 2) and Interference PMI (Indication Method 3) Information.

In the MU-CSI report indication method 1 proposed by the present invention, 11, the MU-PMI determined by the BS is allocated together with the aperiodic feedback indicator, and the UE generates a CQI corresponding to the context using the MU-PMI and reports the CQI to the BS.

5 is a diagram illustrating a method for a BS to indicate an MU-CSI report to a UE according to an embodiment of the present invention.

5, the BS 501 uses the MU-CSI report indication method 1 to determine the MU-PMIs 507, 508, 509 and 510, and reports the MU-CSI using the MU- More specifically, the PMI having the best performance in the SU-MIMO state and the MU-MIMO state may be different from the existing terminal 502 (506, 507).

As shown in FIG. 5, the existing MS 502 determines a current channel and an interference condition, selects a PMI 506 having the best performance for the MS 502 to determine itself, Reports to the base station together with the CQI. However, since such a single user-based PMI, i.e., SU-PMI, does not consider efficiency from the viewpoint of the entire system, it is difficult to operate an efficient MU-MIMO system.

The existing Rel.11 terminal can not obtain information on the PMI that other terminals can use efficiently because the terminal can not use the PMIs 508, 508 and 508 used by the other terminals 503, 504, PMI 507, which is determined to be advantageous for operating the MU-MIMO system, is guaranteed to be orthogonality with the SU-PMI 509 and the SU-PMI 509, (506) to generate channel state information. In the conventional CSI report, a mobile station itself reports a PMI by determining a channel condition, and there is no method by which a base station can directly designate an MU-PMI and receive channel state information in order to operate the MU-MIMO system.

However, when the UE 502 uses the MU-PMI 507 advantageous from the viewpoint of the multi-user system without using the SU-PMI 506 advantageous from the viewpoint of a single user system, Accordingly, the terminal 502 obtains more scheduling opportunities, thereby reducing the waiting time required for transmission and improving the data transmission speed. Accordingly, the base station directly designates the MU-PMI using the MU-CSI report indication method 1 of the present invention, and the terminal can acquire the channel state information in the multi-user environment.

MU-CSI report The method for designating MU-PMI using indication method 1 is as follows.

MU-PMI designation method 1: One of predetermined PMIs is designated as MU-PMI to generate channel state information

MU-PMI designation method 2: Based on the generated SU-PMI, MU-PMI is indicated through a relative value to generate channel state information

In the MU-PMI Assignment Method 1, the decision is made in advance by the base station, and in Designation Method 2, the decision is made based on the SU-PMI reported by the UE.

Tables 3a and 3b illustrate a method for specifying MU-PMI using the MU-PMI indication method 1 when the aperiodic feedback indicator is 2 bits or 3 bits.

[Table 3a]

[Table 3b]

Table 3a defines a method for performing MU-PMI designation and aperiodic feedback using a two-bit aperiodic feedback indicator, and defines a method for performing MU-PMI designation and aperiodic feedback using a three bit non-periodic feedback indicator.

In a conventional aperiodic feedback indicator, a set of corresponding component carriers (CCs) or a set of CSI processes in a CA (Carrier Aggregation) and CoMP (Coordinated Multi- Point transmission and reception) (Radio Resource Control), and instructs the non-periodic feedback for the entire CC or CSI process, or the non-periodic feedback for the entire CC or CSI process by designating sets 1 and 2 . Likewise, in the MU-PMI indication method 1 proposed by the present invention, the MU-PMI to be used can be set in advance via the RRC, and the channel state information can be instructed to be fed back via the corresponding MU- have. In the case where the aperiodic feedback indicator has a size of 1 bit as in the existing standard, a value corresponding to '00', '000', '01', or '001' may be used in Tables 3a and 3b .

In the case of the above-mentioned MU-PMI indication method 1, it is advantageous that the base station can instruct the terminal exactly to the desired PMI to perform MU-CSI report. However, since the desired MU-PMI is indicated through the RRC, the number of MU-PMIs that can be indicated is limited. In addition, it is impossible to dynamically set a possible MU-PMI set according to a channel change between a base station and a mobile station, so that the MU-PMI set must be instructed only within a limited set.

6 is a diagram illustrating a method for a BS to indicate an MU-CSI report to a UE according to another embodiment of the present invention.

Referring to FIG. 6, the BS refers to the SU-PMI 601 reported by the MS according to the MU-PMI indication method 2 and determines whether the MS transmits the MU- -PMIs 602, 603, and 604, and to use this to report MU-CSI.

In FIG. 6, it is assumed that the UE selects SU-PMI as 0 (601) based on a single user environment. In this case, the MU-PMI indication method 2 includes a SU-PMI 601 and an MU-PMI 601 together with an aperiodic channel status information report indication based on the SU-PMI 601 generated as described above, (602, 603, 604), and allows the terminal to select the MU-PMI using its relative value. The UE acquires MU-PMI information, generates channel state information for MU-MIMO based on the received MU-PMI information, and reports the signal to the base station through non-periodic channel state information reporting. At this time, the SU-PMI 601 required for reference can be based on the following PMI.

SU-PMI reference method for MU-PMI generation method 1: The base station reports the periodic channel state information of the UE and indicates the difference with the MU-PMI based on the PMI reported in advance and generates channel state information

SU-PMI reference method for MU-PMI generation Method 2: The BS reports the previously reported non-periodic channel state information report to the UE and indicates the difference with the MU-PMI based on the PMI reported in advance and generates channel state information

SU-PMI reference method for MU-PMI generation Method 3: The base station reports the non-periodic channel state information report to the UE and reports the difference to the MU-PMI based on the SU-PMI to be reported to generate channel state information

 7 is a diagram illustrating a method for a BS to indicate an MU-CSI report to a UE according to another embodiment of the present invention.

 Referring to FIG. 7, the BS refers to SU-PMI 701 previously reported through periodic channel state information reporting of a UE according to SU-PMI reference method 1, and transmits a MU- PMI 704, and report the MU-CSI to the terminal using the PMI 704.

In FIG. 7, the UE periodically reports RI, PMI, and CQI (700, 701, 702) to the base station. The base station determines the MU-PMI suitable for MU-MIMO operation based on the periodic channel state information report of the UE, and instructs the UE to report MU-CSI based on the determined MU-PMI. Based on this, the UE uses the most recently reported periodic channel state information report or the PMI 701 based on the most recent cyclic channel state information report prior to the nk subframe to use for reporting aperiodic channel state information The MU-PMI 704 is obtained.

FIG. 8 is a diagram illustrating a method in which a BS indicates a MU-CSI report to a UE when the PMI structure is a two-dimensional structure of i1 / i2 in the embodiment of FIG.

In the existing LTE system, when the number of logical antenna ports is 8 or more, PMI is reported as a two-dimensional structure of i1 / i2 to reduce feedback overhead. FIG. 8 shows a method of instructing channel status information reporting together with MU-PMI using SU-PMI reference method 1 in this case. The UE periodically reports PTI, RI, PMI1 (i1), PMI2 (i2), CQI (800, 801, 802, 803, 804) to the base station. As in the above example, the base station determines the MU-PMI suitable for performing the MU-MIMO operation based on the periodic channel state information report of the UE, and instructs the UE to report the MU-CSI based on the determined MU-PMI. At this time, this indication may be applied equally to each PMI dimension, and the PMI offset between the SU-PMI and the MU-PMI may be indicated in two dimensions and applied differently to each PMI. 7, based on the PMI based on the most recently reported periodic channel state information report or the latest periodic channel state information report prior to the nk subframe, the UE in FIG. - Obtain PMI.

When the MU-PMI is specified using the SU-PMI reference method 1 described above, there is a disadvantage that the periodic channel state information report and the aperiodic channel state information report are related to each other. The existing cyclic channel state information reporting and the aperiodic channel state information reporting are operated independently of each other and there is no association, but when using this method, they are related to each other. In this case, if the BS does not correctly acquire the reported periodic channel state information, an error may occur in the MU-PMI.

FIG. 9 is a diagram illustrating a method for the BS to indicate the MU-CSI report to the MS according to another embodiment of the present invention.

Referring to FIG. 9, the base station refers to the SU-PMI 901 previously reported through the aperiodic channel state information report of the UE according to the SU-PMI reference method 2, and transmits the MU- -PMI 904 to be selected and report the MU-CSI to the terminal.

9, the UE reports the RI 900, the PMI 901, and the CQI 902 to the base station according to an instruction to report an aperiodic channel state information based on a SU (Single User). The base station determines an MU-PMI 904 suitable for MU-MIMO operation based on the previously reported aperiodic channel state information report, and instructs the UE to report MU-CSI based on the MU-PMI 904. Based on this, the UE reports the non-periodic channel state information based on the most recently reported non-periodic channel state information report or the PMI (901) based on the latest non-periodic channel state information report prior to the nk sub-frame And obtains the MU-PMI 904 for use.

 FIG. 10 is a diagram illustrating a method in which a base station indicates an MU-CSI report to a terminal when the PMI structure is a two-dimensional structure of i1 / i2, as in the embodiment of FIG.

PMI reference method 2 when the PMI structure is a two-dimensional structure of i ₁ / i ₂ , as in FIG. 8, to indicate channel state information reporting together with the MU-PMI. The UE reports the RI 1000, PMI1 (i1) 1001, PMI2 (i2) 1002, and CQI 1003 to the base station irresponsively in accordance with the SU-based aperiodic channel state information report instruction previously performed . As in the above example, the BS determines the MU-PMI 1004 suitable for MU-MIMO operation based on the aperiodic channel state information report of the UE, and informs the UE of MU- Indicate. 8, the PMI offset between the SU-PMI and the MU-PMI may be two-dimensionally indicated and may be differently applied to the respective PMIs . 10, based on the PMI based on the most recently reported aperiodic channel state information report or the latest non-periodic channel state information report prior to the nk subframe, Find the MU-PMI by

When the SU-PMI is designated using the SU-PMI reference method 2 described above, the periodic channel state information and the aperiodic channel state information report can be operated independently of each other. However, it takes a lot of time to instruct the reporting of the aperiodic channel state information to receive the SU-PMI, and then to instruct the reporting of the aperiodic channel state information for the MU-PMI. In addition, the aperiodic channel state information report reports accurate channel state information through a large amount of feedback, and therefore, the amount of time and frequency resources consumed in the periodic channel state information report decreases, thereby degrading data transmission performance.

In addition, the aperiodic channel state information report needs to be divided into a channel state information report for the SU-MIMO operation and a channel state information report for the MU-MIMO operation. These methods are as follows.

Indication of channel state information reporting for MU and SU in non-periodic channel state information reporting Method 1: Indication of MU or SU CSI-report in DCI format (Downlink Control Information Format) including reporting of non-periodic channel state information field (MU-CSI indicator).

In the non-periodic channel state information report, the channel state information report for the MU and the SU is indicated. Method 2: The non-periodic channel state information reporting method is modified to use the MU-CSI report or the SU-CSI report for each index.

When instructing the UE using the above two methods, it can be instructed to report aperiodic channel status information by distinguishing it as an MU-CSI report or an SU-CSI report. In the aperiodic channel state information report, if the channel state information reporting for MU and SU is classified using indicator indication method 1, a new field of about 1 bit, ie MU-CSI indicator, is added to the existing DCI field to indicate whether it is MU or SU . In this case, when the MU indicator is 0, there is an advantage that the existing non-periodic channel state information reporting table can be used for CA or CoMP, and when 1, a new table can be used. In the aperiodic channel status information report, if the channel status information report for MU and SU is classified using the indicator indication method 2, the existing table size can be maintained and the case for the CSI report can be limited or the MU-CSI report can be used. The existing non-periodic channel state information reporting table may be extended and used. If the existing table size is maintained, the number of cases for the existing CSI-report should be reduced to support the MU. However, if the existing table is to be extended, it is disadvantageous that additional overhead should be used for reporting the channel state information for MU and SU in the aperiodic channel state information report as in the case of the index indication method 1.

 11 is a diagram illustrating a method for a BS to indicate an MU-CSI report to a UE according to another embodiment of the present invention.

 Referring to FIG. 11, the BS refers to the SU-PMI 1101 to report on non-periodic channel status information reported by the UE according to the SU-PMI reference method 3, and calculates a relative value with respect to the MU- To select the MU-PMI, and use the MU-PMI to report the MU-CSI to the terminal.

In FIG. 11, the BS determines an MU-PMI suitable for performing an MU-MIMO operation according to a previously reported periodic or aperiodic channel state information report indication and instructs the MS to report MU-CSI based on the determined MU-PMI . The UE derives the SU-PMI 1101 based on the current channel state based on the current channel state, and obtains the MU-PMI by applying an offset given to the derived SU-PMI along with the report of the non-periodic channel status information report. At this time, SU-PMI should be reported together to determine which MU-PMI is derived based on which SU-PMI. Based on this, an MU-CQI 1103 suitable for the MU operation is obtained and reported together. The SU-CQI 1102 obtained based on the SU-PMI may or may not be reported together. The example of FIG. 11 is shown assuming that it is reported.

FIG. 12 is a diagram illustrating a method of reporting an MU-PMI together when using the SU-PMI reference method 3 mentioned in FIG.

By reporting the MU-PMI together with the information of FIG. 11 as shown in FIG. 12, it is possible to minimize information collision between the base station and the terminal. However, since the base station knows the MU-PMI offset and the SU-PMI is also received through the report, if the base station knows only one of the two information, the base station can check each PMI. 11 and 12, the method of reporting only the MU-PMI is also applicable similarly to FIGS.

When the SU-PMI is designated using the SU-PMI reference method 3, the periodic channel state information and the aperiodic channel state information report can be operated independently of each other. However, as the channel state changes, the SU-PMI of the current channel and the SU-PMI of the actual UE may differ, and thus the actual MU-PMI when the offset specified by the BS is applied may be different . However, Reference Methods 1 and 2 described above have an advantage in that the method of Reference Method 3 has no dependency while the other periodic or aperiodic channel state information reporting and the aperiodic channel state information reporting for MU are mutually dependent .

In the MU-PMI Assignment Method 2, a method of indicating an offset between the SU-PMI and the MU-PMI to the UE based on the SU-PMI reference methods described above is as follows.

To indicate the offset between SU-PMI and MU-PMI Method 1: Designate MU-PMI by designating the absolute PMI index offset in one dimension

Method of indicating offset between SU-PMI and MU-PMI Method 2: Designating MU-PMI by designating offset in one dimension according to a predetermined relative PMI position

Method of offset between SU-PMI and MU-PMI Method 3: Designation of MU-PMI by designating the offset of absolute PMI index in multi-dimension

Method of indicating offset between SU-PMI and MU-PMI 4: Designating MU-PMI by designating offset in multidimension according to predetermined relative PMI position

Method of indicating offset between SU-PMI and MU-PMI 5: Assignment of MU-PMI based on offset based on absolute PMI index offset or predetermined relative PMI position according to dimension

Tables 4a and 4b illustrate a method for indicating MU-CSI report together with the offset between SU-PMI and MU-PMI using offset indication methods 1 and 2 between SU-PMI and MU-PMI.

[Table 4a]

[Table 4b]

Table 4a defines a method for performing MU-PMI designation and aperiodic feedback through a two bit non-periodic feedback indicator (CSI request field), and Table 4b shows MU-PMI designation and non-periodic feedback Method.

As shown in Tables 4a and 4b, the BS may instruct the non-periodic channel state information reporting for the MU-MIMO operation together with the MU-PMI offset for reporting the aperiodic channel state information. A field '00' or '000' in each table means that no reporting of aperiodic channel state information is required, and '01' or '001' indicates that the UE generates SU- Based on the MU-PMI report. The other fields additionally indicate the offset between the SU-PMI and the MU-PMI together with the indication of reporting the aperiodic channel status information, and this operation may vary depending on whether the offset indication method 1 or 2 between SU-PMI and MU- have.

The operation of using the offset indication method 1 between SU-PMI and MU-PMI is as follows. For example, it is assumed that the UE reports the reference SU-PMI through a periodic or non-periodic channel state information report with a reference value of 5, which indicates an offset of the absolute PMI index in one dimension and designates the MU-PMI. At this time, the BS attempts to instruct the UE to report the aperiodic channel state information to the PMI 6 considering the current channel status between the BS and the UE and scheduling with the other UEs. In this case, the base station triggers the index by +1 in the reference SU-PMI using the aperiodic channel state information report indication field '10' in Table 4a, so that the terminal assumes MU-PMI to be 6 and performs MU-CSI report can do. If the number of bits of the aperiodic channel state information report is increased as shown in Table 4b, the non-periodic channel state information reporting can be instructed for a larger number of cases. In this case, use the opposite PMI when the reference SU-PMI is 0 and the offset is -1 (for example, when the entire codebook size is 16), or the PMI 15 ), Or does not report an aperiodic channel state, or the like.

Table 5 is a table illustrating the relationship between PMIs to explain the offset indication method 2 between SU-PMI and MU-PMI.

[Table 5]

First, it is assumed that relative offset between SU-PMI and MU-PMI is predefined in the standard or promised through RRC, as shown in Table 5, unlike offset indication method 1 between SU-PMI and MU-PMI. In this case, the offset between the SU-PMI and the MU-PMI does not always have to be defined as shown in Table 5, and the PMI is set in advance when the offset is guaranteed for the corresponding PMI or the size of the relative offset is set It is also possible to do so.

The operation in the case of using the offset indication method 2 between SU-PMI and MU-PMI based on Table 5 is as follows. For example, if the UE reports a reference SU-PMI with a periodic or aperiodic channel state information report of 5 as a reference, I suppose. At this time, the BS attempts to instruct the UE to report the aperiodic channel state information to the PMI 9 considering the channel condition between the current BS and the UE and the scheduling with the other UEs. In this case, when the non-periodic channel state information report indication field '10' of Table 4a is used, since the reference SU-PMI is 5 in the state of 5, the base station assumes that the MU-PMI is 9 according to Table 5 , And MU-CSI report. If the number of bits of the aperiodic channel state information report is increased as shown in Table 4b, the non-periodic channel state information reporting can be instructed for a larger number of cases. Also, for the operation that goes out of the defined PMI range as the offset indication method 1 between the SU-PMI and the MU-PMI, use the opposite PMI (refer to the case where the SU-PMI is 0 and the MU-PMI offset is -1 PMI 12 is used in the case of a non-periodic channel status report), or non-periodic channel status report is not performed.

In the examples of Tables 4a and 4b, the absolute number of the offset can be changed according to the situation and the usage. Unlike the Tables 4a and 4b, only the value having a positive offset can be used, So that it can be flexibly operated.

Tables 6a and 6b illustrate a method for indicating MU-CSI report together with the offset between SU-PMI and MU-PMI using offset indication method 3, 4 and 5 between SU-PMI and MU-PMI.

[Table 6a]

[Table 6b]

Table 6a defines a method for performing MU-PMI designation and aperiodic feedback using a two-bit aperiodic feedback indicator, and Table 6b defines a method for performing MU-PMI designation and aperiodic feedback using a three bit aperiodic feedback indicator.

As shown in Tables 6a and 6b, the BS may instruct the non-periodic channel state information reporting for the MU-MIMO operation together with the MU-PMI offset for reporting the aperiodic channel state information. As in the offset indication methods 1 and 2 between the SU-PMI and the MU-PMI, the field '00' or '000' in the respective tables means that the report of the aperiodic channel state information is not needed, 'Or' 001 'indicates that the UE reports the MU-PMI based on the SU-PMI generated in the same manner as the conventional method. The other fields additionally indicate the offset between the SU-PMI and the MU-PMI together with the indication of reporting the aperiodic channel status information, and this operation depends on whether the offset indication method 3, 4 or 5 between SU-PMI and MU- It can be different. The difference between the SU-PMI and MU-PMI offset indication methods 3, 4 and 5 is different from the offset indication methods 1 and 2 between SU-PMI and MU-PMI mentioned above. There are a plurality of PMIs. Accordingly, various embodiments are possible depending on which PMIs are mapped to the respective dimensions.

The offset indication method 3 between the SU-PMI and the MU-PMI indicates the MU-PMI by indicating the offset of the absolute PMI index in a multi-dimensional manner. Therefore, it is possible to specify MU-PMI by indicating PMI offsets to PMIs of various dimensions. As shown in FIGS. 8 and 10, when a plurality of PMIs having a structure of i _{1 /} i ₂ used for eight local antennas are used in the existing system, the h dimension is mapped to i ₁ ), And PMI offset dimension corresponding to each PMI dimension can be allocated in a manner of mapping v dimension to i2. Of course, in this embodiment, + h1 and + v1 may be denoted for each PMI in the same manner as i ₁ +1 and i ₂ +1. To illustrate this approach, we assume that the terminal reports the reference SU-PMI through periodic or aperiodic channel state information reporting with i ₁ = 5 and i ₂ = 7. At this time, the BS instructs the UE to report the aperiodic channel state information to the i ₁ -dimensional PMI 6 without changing the i ₂ -dimensional PMI considering the channel condition between the current BS and the UE and scheduling with other UEs I will try. In this case, the base station assumes that the MU-PMI is 6 in the case of i ₁ and 7 in the case of i ₂ using the aperiodic channel state information report indication field '10' in Table 6a, and MU-CSI report . In contrast to the previous example, it is also possible to designate a field that can change the PMI of i ₂ -dimensions and offset two dimensions at the same time, and simultaneously indicate the MU-PMI offset of i ₁ and i ₂ dimensions Do. If the number of bits of the aperiodic channel state information report is increased as shown in Table 6b, the non-periodic channel state information reporting can be instructed for a larger number of cases. However, in this case, the amount of overhead is increased when DCI format is transmitted for scheduling. Therefore, such a table should be carefully designed considering the amount of MU-PMI required and the DCI overhead incurred.

In addition, the MU-PMI offset can be indicated in a multidimensional manner for each rank of one PMI dimension, and can be applied by dividing the rank corresponding to one PMI dimension. For example, when the referring SU-PMI is rank 5, and the non-periodic channel state report corresponding to + v1 is set, 5 corresponding to rank 2 is assumed to be MU-PMI, report to the user.

The offset indication method 3 between the SU-PMI and the MU-PMI can be similarly applied to the vertical PMI and the horizontal PMI structure for efficiently applying precoding to many multiple antennas in the FD-MIMO system have. If the vertical PMI is PMI _V and the horizontal PMI is PMI _H , the offset of h dimension specifies the MU-PMI offset of the PMI _H dimension, and the offset of the v dimension specifies the MU-PMI offset of the PMI _V dimension mapping. In addition, if each PMI is assumed to have an existing i ₁ / i ₂ structure, an MU-PMI offset can be indicated using an aperiodic channel state information reporting indication table composed of four dimensions.

The offset indication method 4 between the SU-PMI and the MU-PMI is a method of designating the MU-PMI by designating the offset in a multidimensional manner according to a predetermined relative PMI position. Similar to the offset indication method 3 between the SU-PMI and the MU-PMI, when the PMI of the i- ₁ / i ₂ structure used in the existing system is used and the number of multiple antennas in the FD- it is applicable to Vertical PMI and Horizontal PMI structures for efficiently applying precoding.

For example, when a PMI having a plurality of dimensions of an i ₁ / i ₂ structure is used, mapping h dimension to i ₁ , mapping v dimension to i _2, and PMI offset corresponding to each PMI dimension Dimensions can be assigned. Of course, in this embodiment, + h1 and + v1 may be denoted for each PMI in the same manner as i ₁ +1 and i ₂ +1. To illustrate this approach, we assume that the terminal reports the reference SU-PMI through periodic or aperiodic channel state information reporting with i ₁ = 5 and i ₂ = 7. At this time, the base station instructs the UE to report aperiodic channel state information for i ₁ -dimensional PMI 9, without changing the PMI of the i ₂ -dimensional, considering the channel condition between the current BS and the UE and scheduling with other UEs I will try. In this case, as mentioned in the above example, PMI promulgation based on the relative offset similar to Table 5 should be performed. In this case, the offset between SU-PMI and MU-PMI does not always have to be defined as shown in Table 5 , The size of the relative offset can be guaranteed, or the desired PMI can be set in advance when the offset is given only for the corresponding PMI. The base station when triggered by only +1 in the vertical PMI SU-PMI referenced using an aperiodic channel state information report indication field is '10' of the table 6a is a pre +4 as provided in Table 5, the terminal ₁ of the i-dimensional PMI Is 9, and since horizontal PMI is not indicated, i ₂ can be set to 7, and MU-CSI report can be made without changing. Also, as shown in Table 6b, when the number of bits of the aperiodic channel state information report is increased, it is possible to instruct the reporting of the aperiodic channel state information for a larger number of cases. In contrast to the previous example, it is also possible to designate a field that can change the PMI of i ₂ -dimensions and offset two dimensions at the same time, and simultaneously indicate the MU-PMI offset of i ₁ and i ₂ dimensions Do.

If the number of bits of the aperiodic channel state information report is increased as shown in Table 6b, the non-periodic channel state information reporting can be instructed for a larger number of cases. However, in this case, the amount of overhead increases when DCI format is transmitted for scheduling. Therefore, such a table should be carefully designed considering the amount of MU-PMI required and the DCI overhead incurred.

Similarly to the offset indication method 3 between the SU-PMI and the MU-PMI, the MU-PMI offset can be indicated in a multi-dimensional manner for each rank for one PMI dimension. . ≪ / RTI > For example, if the reference i ₁ PMI is 5, which corresponds to rank 1, it is set as a multi-dimensional +1 indication so that when the corresponding aperiodic channel status report is set, it is assumed that the MU-CSI report is reported by designating the MU-PMI corresponding to the rank.

The offset indication method 4 between the SU-PMI and the MU-PMI can be similarly applied to the vertical PMI and the horizontal PMI structures for efficiently applying the precoding to many multiple antennas in the FD-MIMO system. The offset of the h dimension specifies the relative MU-PMI offset of the PMI _H dimension and the offset of the v dimension can be mapped to specify the relative MU-PMI offset of the PMI _V dimension. In addition, if each PMI is assumed to have an existing i ₁ / i ₂ structure, the relative MU-PMI offset can be indicated using a 4-dimensional aperiodic channel state information reporting indication table.

The offset indication method 5 between the SU-PMI and the MU-PMI is a method of assigning the MU-PMI based on the offset according to the absolute PMI index offset or the predetermined relative PMI position according to the dimension. This is a method that uses the offset indication methods 3 and 4 between SU-PMI and MU-PMI according to the use of each PMI dimension. In the case of i ₁ , the absolute PMI offset the instruction and, i ₂ may specify the MU-PMI using the method such as to indicate the relative offset PMI using an offset indicating how four between SU and MU-PMI-PMI.

In the offset indicating method between the SU-PMI and the MU-PMI, a codebook restriction may be applied to the corresponding PMI through a method supported by the existing standard. This can occur for both absolute and relative PMI offsets, and can be solved through the following predefined rules.

PMI calculation when PMI restriction exists Method 1: The PMI is skipped and offset is applied.

PMI calculation when PMI restriction exists Method 2: Apply the offset including the PMI restriction.

PMI calculation when PMI restriction exists Method 3: When there is a codebook restriction, this method is not applied.

In the case of PMI calculation method 1 when PMI restriction is present, it is simply applicable. For example, if the reference SU-PMI is 2 and the MU-PMI offset is 3 and the codebook restriction is placed on PMI 4, then the calculated MU-PMI can be calculated as 2-3-5-6 have. PMI calculation when PMI restriction exists In the case of method 2, the rule for the case where the final calculated PMI is the limited PMI is needed. In the above example, it can be calculated as 2-3-4-5, but assuming that codebook restriction is placed on PMI 5, the definition of the rule is needed again. In this case, among the above three methods, methods 1 and 3 can be applied again. If 1 is applied, PMI 6 will be used to calculate MU-PMI. If 3 is applied, MU- You will be fed back using the SU-CSI report. The difference between applying Calculation Method 1 first and Applying Calculation Method 2 and applying 1 when an exception occurs can be illustrated as follows. If SU-PMI is 2 and MU-PMI offset is 3, and codebook restriction is applied to PMI 3 and 4, if 1 is applied first, it is calculated as 2-5-6-7 and MU-PMI And MU-PMI is judged to be 5 if it is applied first.

MU-CSI report Indication method 2 is a method of instructing the terminal to perform an MU-CSI report together with the IMR determined by the base station according to a desired interference condition. In LTE Release 11, a system capable of Coordinated MultiPoint Transmission and Reception (CoMP) establishes a CSI-process on a terminal through a centralized controller that controls the transmission and reception of multiple TPs. Through the cooperative communication using the CSI-processes, the UE supports up to four radio channel status reports such as CQIs for the radio channels with the base stations receiving the downlink data. The UE transmits channel state information to a base station for a channel corresponding to a CSI-RS (Channel Status Information Reference Signal) designated in a promised manner to the base station according to each CSI-Process set by the base station. In this case, the UE allocates one CSI-RS and one IMR per CSI-Process, and can obtain information on the channel for receiving the signal and the strength of the interference signal. The CSI- Up to three can be set. A method for allocating an IMR corresponding to one CSI-process in order to measure the MU-MIMO interference to the base station and feedback the channel state according to the present invention is as follows.

Define IMR for each new CSI-process: Define time and frequency resources corresponding to multiple IMRs in one CSI-process.

The new IMR defining method according to the present invention is different from the existing LTE Release 11 in which a base station defines one IMR in one CSI-process to measure MU-MIMO interference, and a plurality of IMR And the MU-MIMO interference is measured. In other words, one CSI-Process is defined through a single CSI-RS and multiple IMR resources. In the past, channel status was reported using one CSI-RS and one IMR resource, In CSI-Process, it is possible to report the channel status for various channel conditions by combining CSI-RS and multiple IMR resources.

FIG. 13 is a diagram illustrating a method in which a base station indicates an MU-CSI report to a terminal according to another embodiment of the present invention, and the terminal reports an MU-CSI according to an instruction.

Referring to FIG. 13, a method of including one CSI-RS and a plurality of IMRs in one CSI-process, and a CSI-RS and IMR combination for each CSI-process may be used to report channel state information.

1300 exemplifies a CSI-Process including one CSI-RS and a plurality of IMRs. The CSI-process of 1300 includes one CSI-RS and three IMRs 1301, 1302 and 1303. In this example, the IMR is composed of three IMRs, but the number of IMRs in actual use includes both cases in which the number of IMRs is set to two or more than three. Assuming that CSI-Process 1300 is defined, report example 1 1304 assumes CSI-RS as a signal using this CSI-Process and assumes that the power of IMR ₁ 1305 is interference, And the state is reported. The report example 2 1306 assumes that the CSI-RS is a signal using the CSI-Process and assumes that the power of the IMR ₂ 1307 and the IMR ₃ 1308 is Interference is assumed and the channel status is reported. Similarly, the report example 3 1309 assumes that a CSI-RS is a signal using the CSI-Process, assuming that the CSI-Process 1300 is defined, and the power of all the IMRs 1310, 1311, and 1312 Is assumed to be interference and the channel status is reported. When a plurality of IMRs are set in one CSI-process, the channel status can be reported considering the number of various cases. In the present example, a representative case is described in which channel state information is reported using one IMR, two IMRs, and three IMRs in the case of various combinations. In the present invention, As well as the number of all cases in which channel status is reported using one CSI-RS and a plurality of IMRs.

In order to allow the CSI-Process to report the channel state information according to the number of each IMR, the MU-CSI report indication method 2 is used to transmit the MU-CSI report together with the IMR corresponding to the desired interference condition . ≪ / RTI >

[Table 7a]

[Table 7b]

Table 7a defines the method of performing IMR designation and aperiodic feedback through a two-bit aperiodic feedback indicator, and Table 7b defines a method of performing IMR designation and aperiodic feedback using a three-bit aperiodic feedback indicator.

As shown in Tables 7a and 7b, the BS may instruct the non-periodic channel state information reporting for the MU-MIMO operation together with the corresponding IMR set for the non-periodic channel state information reporting. Like the offset indication methods between the SU-PMI and the MU-PMI, the field '00' or '000' in each table means that no report of the aperiodic channel state information is needed, and '01' 001 'is the same as the UE instructing the non-periodic channel state information reporting on all CSI-processes in the existing CA (Carrier Aggregation) or CoMP (Coordinated Multi- Point transmission and reception) Report. Other fields indicate whether to report the channel state by considering the power of certain IMRs together with an aperiodic channel state information reporting indication as interference in reporting channel state information. Each set of IMRs includes one or more IMRs, which may be pre-defined in the standard or preset by the base station in the terminal via L1 or RRC signaling. If more bits are used to indicate the IMR set as shown in Table 7b, the non-periodic channel state information reporting can be instructed for a larger number of sets.

The MU-CSI report indication method 3 is a method of instructing the terminal with the MU-CSI report together with the PMI to be determined as interference desired by the base station. As described above, a system capable of CoMP in LTE Release 11 sets up a CSI-process in a terminal through a centralized controller that controls transmission / reception of a plurality of TPs. Through the cooperative communication using the CSI-processes, the UE supports up to four radio channel status reports such as CQIs for the radio channels with the base stations receiving the downlink data. The UE transmits channel state information to the base station for a channel corresponding to the designated CSI-RS in a promised manner to the base station according to each CSI-Process set by the base station. In this case, the UE allocates one CSI-RS and one IMR per CSI-Process, and can obtain information on the channel for receiving the signal and the strength of the interference signal. The CSI- Up to three can be set. In this case, when the BS designates not only the power measured through the IMR of the corresponding CSI-Process but also a specific PMI and acts as a further interference using a precoder corresponding to the PMI to the channel through the CSI-RS It is also possible to perform CSI-report. This interference is called " emulated interference ".

Tables 8a and 8b illustrate the case where the non-periodic channel state information reporting table for the existing CA and CoMP and the non-periodic channel state information reporting table according to the MU-CSI report indicating method 1 are combined and used.

[Table 8a]

[Table 8b]

Table 8a defines the method of performing the interference PMI designation and the aperiodic feedback through the two bit aperiodic feedback indicator and defines the method of performing the interference PMI designation and aperiodic feedback through the three bit non-periodic feedback indicator of Table 8b.

As shown in Tables 8a and 8b, the BS may instruct the non-periodic channel state information reporting for the MU-MIMO operation together with the corresponding PMI or PMI set for reporting the aperiodic channel state information. Like the offset indication methods between the SU-PMI and the MU-PMI, the field '00' or '000' in each table means that no report of the aperiodic channel state information is needed, and '01' 001 'indicates that the UE reports the channel status considering all the IMRs in the same manner as the UE instructs the non-periodic channel state information reporting on all CSI-processes in the existing CA or CoMP. Other fields may be used for reporting an aperiodic channel status information report, and for determining a certain PMI as an interference, such as Cell Specific Reference Signal (CRS), Demodulation Reference Signal (DM-RS), Channel Status Information Reference Signal It calculates how the corresponding precoder acts as an interference to the derived channel and indicates that it should report the channel condition considering interference with IMR. Each PMI set includes one or a plurality of PMIs, which may be predefined in the standard or preset in the terminal by the base station via L1 or RRC signaling.

If more bits are used to indicate the set of interfering PMIs than Table 8a, as shown in Table 8b, non-periodic channel state information reporting may be indicated for a larger number of sets. In the above example, the interference PMIs are defined by pre-defining the PMI aggregate. However, this method can directly define the interference PMI as well as the offset between the SU-PMI and the interference PMI, as in the MU-PMI and MU- The relative PMI can also be indicated by a relative indication.

As described above, the MU-CSI report indication methods 1, 2, and 3 described above are different from the conventional CA and CoMP tables in that broadcasting is performed through a BCH (Broadcast Control Channel), setting is performed through RRC, It is possible to switch to an aperiodic channel state information reporting table for MU-CSI and to use it. However, it is also possible to expand the above table in combination with the non-periodic channel state information reporting table for existing CA and CoMP. Tables 9a and 9b illustrate a case where the non-periodic channel state information reporting table for the existing CA and CoMP and the non-periodic channel state information reporting table according to the MU-CSI report indicating method 1 are combined and used.

[Table 9a]

[Table 9b]

Table 9a defines a method for performing MU-PMI assignment and aperiodic feedback through a three-bit aperiodic feedback indicator, and Table 9b defines a method for performing IMR assignment and aperiodic feedback using a three bit aperiodic feedback indicator.

As illustrated in Tables 9a and 9b, the non-periodic channel state information report indication table in the MU-CSI report indication methods 1, 2 and 3 described above is combined with the non-periodic channel state information report indication table for the existing CoMP You can create a new type of table. In addition, in order to distinguish the SU-based CSI report from the MU-based CSI report in the above table, the table is divided into the aperiodic CSI report and the aperiodic MU-CSI report. However, the above example is only one of such possibilities. The CSI report table can be generated by dividing the classification by various methods such as type 1, type 2, type a, and type b.

14 is a view for explaining an operation of a base station indicating a MU-CSI report to a terminal according to the present invention.

Referring to FIG. 14, the BS determines (1400) a situation in which the MS requires MU-CSI report and determines (1401) use of an aperiodic channel state information reporting table for MU-CSI report, (1402) with the MU-CSI report indicator to the mobile station by designating the MU-PMI offset and receive the MU-CSI report (1403) from the mobile station.

In step 1400 of FIG. 14, the BS reports an MU-CSI report to the UE in consideration of various factors such as periodic and aperiodic channel state information reported by the UE to the BS, channel state information of other UEs, It is necessary to use the non-periodic channel state information reporting table. In step 1401, it is determined whether to use the table based on the result obtained in step 1400, and it is notified through L1 signaling or RRC signaling. In step 1402, the BS transmits the desired MU-PMI or the interference PMI to the UE along with the non-periodic channel status information report indicator, and the UE receiving the information reports an aperiodic channel status report table for the MU- The MU-PMI or the interference PMI, and reports the aperiodic channel state information to the base station.

15 is a diagram illustrating an operation of a terminal reporting an MU-CSI to a base station according to the present invention.

Referring to FIG. 15, in step 1501, the UE instructs to use a table together with an acyclic channel state information report instruction 1500 and an absolute PMI value or offset for an MU-PMI or an interference PMI The MU-CSI report is transmitted 1504 to the base station by using the table 1502 or the non-periodic channel state information report 1503 for the existing CA or CoMP when there is no instruction to use the table 1503 .

In step 1500 of FIG. 15, the UE receives an aperiodic channel status information report indication from the BS. In step 1501, the BS periodically and aperiodically reports the MU-CSI report to the UE in consideration of various factors such as periodic and aperiodic channel state information reported by the UE to the BS, channel state information reporting of other UEs, CSI report using L1 signaling or RRC signaling according to necessity to use the channel state information reporting table, the base station determines trigger information for the MU-CSI report MU-PMI or interference PMI) with an aperiodic channel state information report indicator, measuring channel state using the MU-CSI report trigger information, and generating non-periodic channel state information based on the measured result To the base station. However, if the BS does not notify the UE that it does not need to use the non-periodic channel state information reporting table for MU-CSI report and interprets it as same as the non-periodic channel state indicator in step 1503, And then report channel state information.

16 is a view for explaining an operation of a base station indicating a MU-CSI report to a terminal according to another embodiment of the present invention.

Referring to FIG. 16, when a channel state information report field for an existing CA or CoMP and a MU-CSI report field exist at the same time in a table, the BS detects a situation in which a terminal needs an MU-CSI report, Periodic channel state information reporting for the CSI report is required 1600. Accordingly, an MIMO-PMI or an interference PMI for the MU-CSI report is determined to be an absolute PMI value or a PMI offset, (1601) with the indicator and receiving (1602) an MU-CSI report from the terminal.

In step 1600 of FIG. 16, the BS generates an MU-CSI report in consideration of various factors such as periodic and aperiodic channel state information reported by the MS, channel state information of the MS, and loading of the BS. It is necessary to use non-periodic channel state information reporting for the non-periodic channel state information. In step 1601, it is determined whether to set the use of aperiodic channel state information reporting for the MU-CSI report based on the result obtained in step 1600, and an MU-CSI report together with the desired MU-PMI or interference PMI is transmitted through the aperiodic channel status reporting indicator And transmits the used information to the terminal. In step 1602, when the UE receives the non-periodic channel state information report, the UE receives the MU-CSI report.

17 is a diagram illustrating an operation of a terminal reporting an MU-CSI to a base station according to another embodiment of the present invention.

17, when a channel state information report field for an existing CA or CoMP and a field for an MU-CSI report exist at the same time in one table, the UE receives an aperiodic channel state information report indication 1700 from the base station , An absolute PMI value or PMI offset for an MU-PMI or an interference PMI is specified 1701, a MU-CSI report is transmitted 1704 to a base station using a specific field 1702, If the MU-PMI is not specified in the state information reporting field, the non-periodic channel state information reporting for the existing CA or CoMP may be performed (1503).

In step 1700 of FIG. 17, the UE receives an aperiodic channel status information report indication from the BS. In step 1701, the BS periodically and aperiodically reports the MU-CSI report to the UE in consideration of various factors such as periodic and aperiodic channel state information reported by the UE to the BS, channel state information reporting of other UEs, It is determined whether to perform an MU-CSI report on the assumption of a desired MU-PMI or an interference PMI according to whether the channel state information reporting field is set or not, as in steps 1702 and 1704, And the channel state information is reported after confirming whether to report the channel state information.

18 is a view for explaining an operation of a base station indicating a MU-CSI report to a terminal according to another embodiment of the present invention.

Referring to FIG. 18, the BS determines (1800) whether a UE needs a MU-CSI report (1800) and determines whether to use an aperiodic channel state information reporting table for an MU-CSI report (1801) (1802) with the aperiodic channel state information report indicator, and receive (1803) the MU-CSI report from the terminal.

In step 1800 of FIG. 18, the BS reports an MU-CSI report to the UE in consideration of various factors such as periodic and aperiodic channel state information reported by the UE to the BS, channel status information reported by other UEs, It is necessary to use the non-periodic channel state information reporting table. In step 1801, it is determined whether the use is set based on the result obtained in step 1800, and it is notified through L1 signaling or RRC signaling. In step 1802, the BS transmits to the MS, together with the non-periodic channel state information report indicator, which is the IMR corresponding to the desired multi-user interference situation. When the MS receives the information, Lt; / RTI >

FIG. 19 is a diagram illustrating an operation of a terminal reporting an MU-CSI to a base station according to another embodiment of the present invention.

Referring to FIG. 19, in step 1901, the UE receives an instruction for reporting an aperiodic channel state information report 1900 and a table 1901, The MU-CSI report may be transmitted 1904 to the base station or the non-periodic channel state information report may be performed 1903 for the existing CA or CoMP when there is no instruction to use the table.

In step 1900 of FIG. 19, the UE receives an aperiodic channel status information report indication from the BS. In step 1901, the BS periodically and aperiodically reports the MU-CSI report to the UE in consideration of various factors such as periodic and aperiodic channel state information reported by the UE to the BS, channel state information reporting of other UEs, The BS determines whether or not the MU-CSI use is set according to the necessity to use the channel state information reporting table, whether the MIMO-CSI is set up through the L1 signaling or the RRC signaling, The CSI report or the non-periodic channel status indicator is interpreted in the same manner as in the process 1903, and channel state information reporting is performed after confirming whether to report the channel state information.

20 is a view for explaining an operation of a base station indicating an MU-CSI report to a terminal according to another embodiment of the present invention.

20, when a channel state information report field for an existing CA or CoMP exists in one table and a field for an MU-CSI report exists at the same time, the BS detects the situation in which the UE needs the MU-CSI report, (2000), the base station designates the IMRs according to a desired interference condition, and transmits (2001) to the UE together with an aperiodic channel status information report indicator. And receiving (2002) the MU-CSI report.

In step 2000 of FIG. 20, the BS generates an MU-CSI report in consideration of various factors such as periodic and aperiodic channel state information reported by the UE, channel state information of other UEs, It is necessary to use non-periodic channel state information reporting for the non-periodic channel state information. Based on the results obtained in step 2000 in step 2001, non-periodic channel state information reporting instructions for the MU-CSI report are provided through the field of the aperiodic channel state information reporting indicator, together with the indication of the IMRs corresponding to the desired multi- To the terminal. In step 2002, when the UE receives this information, it reports the non-periodic channel state information to the BS and receives the MU-CSI report.

21 is a view for explaining an operation of a terminal reporting an MU-CSI to a base station according to another embodiment of the present invention.

21, when a channel state information report field for an existing CA or CoMP and a field for an MU-CSI report exist at the same time in one table, the UE receives an aperiodic channel state information report indication 2100 from the base station (2104), the MU-CSI report is transmitted to the base station (2104), or the field of the non-periodic channel state information report is transmitted to the IMR The non-periodic channel state information reporting for the existing CA or CoMP may be performed (1503).

In step 2100 of FIG. 21, the UE receives an aperiodic channel status information report indication from the BS. In step 2101, in consideration of various factors such as reporting periodic and aperiodic channel state information reported by the mobile station to the base station, reporting channel state information of other mobile stations, loading of the current base station in step 2101, It is determined whether the MU-CSI report is to be performed on the assumption of the desired MU-PMI according to whether the channel state information reporting field is set or the same as the existing aperiodic channel state indicator as in step 2103, After confirming whether to report channel state information, channel state information reporting is performed.

22 is a block diagram illustrating an internal structure of a base station according to the present invention.

22, the base station apparatus may include a base station controller 2200, a transmitter 2201, and a receiver 2202. [

22, the base station controller 2200 sets up the use of the MU-CSI table to the terminal in consideration of the periodic and aperiodic channel status information reports of the terminals allocated to the base station, traffic, and the movement status, report through an aperiodic channel state information reporting indicator. At this time, the non-periodic channel state information reporting indicator includes information such as MU-PMI, MU-PMI offset, or IMR, which is MU-CSI report trigger information required when generating an MU-CSI report. The base station controller notifies this channel state information report indicator using the device 2201. [ The base station receives the channel state information measured and reported by the UE using the device 2202. The received channel state information is used for radio resource management for the downlink of the base station after it is determined by the base station controller of the device 2200 that the channel state information is generated using certain MU-PMI and IMRs.

23 is a block diagram showing an internal structure of a terminal according to the present invention.

Referring to FIG. 23, a terminal device may include a terminal controller 2300, a transmitter 2301, and a receiver 2302.

23, the terminal controller 2300 transmits a MU-CSI indication through an MU-CSI report setup or non-periodic channel status information report indicator and an associated MU-PMI report, which is MU-CSI report trigger information, MU-PMI offset or multiple interference conditions. Then, the UE receives a downlink signal from the UE 2302, measures a channel state using the UE, and generates channel state information based on the measured result. The terminal controller measures or generates the multi-user interference according to the MU-PMI and the IMR according to the interference situation, and generates channel state information for the interference. The generated channel state information is transmitted to the base station using the device 2301.

Claims (24)

A method of indicating a channel state information report of a base station in a mobile communication system,
Determining whether non-periodic channel state information reporting for a multi-user channel status information report (MU-CSI report) based on a multi-user terminal is required;
And transmitting the MU-CSI report trigger information and the aperiodic channel status information report indicator to the UE, if necessary. The method according to claim 1,
Wherein,
Periodic or non-periodic channel state information report reported to the base station, a channel state information report of other terminals except for the terminal, or load information of the current base station. Instruction method. The method according to claim 1,
Wherein,
And determining whether to use the aperiodic channel state information reporting table. The method according to claim 1,
Wherein the MU-CSI report trigger information is an MU-PMI (Multi User-Precoding Matrix Indicator) determined by the BS. The method according to claim 1,
Wherein the MU-CSI report trigger information is a plurality of IMR (Interference Measurement Resource) determined by the BS. 5. The method of claim 4,
Wherein the MU-PMI is determined in advance by the base station. 5. The method of claim 4,
Wherein the MU-PMI is determined based on a Single User-Precoding Matrix Indicator (SU-PMI) reported by the UE. A method for reporting channel state information of a terminal in a mobile communication system,
Receiving a multi-user channel status information report (MU-CSI report) trigger information and an aperiodic channel status information report indicator from a base station;
Measuring channel state using the MU-CSI report trigger information;
And reporting the generated aperiodic channel state information to the base station based on the measured result. 9. The method of claim 8,
Wherein the MU-CSI report trigger information is an MU-PMI (Multi User-Precoding Matrix Indicator) determined by the BS. 9. The method of claim 8,
Wherein the MU-CSI report trigger information is a plurality of IMR (Interference Measurement Resource) determined by the BS. 10. The method of claim 9,
Wherein the MU-PMI is determined in advance by the base station. 10. The method of claim 9,
Wherein the MU-PMI is determined based on a Single User-Precoding Matrix Indicator (SU-PMI) reported by the UE. A base station for reporting an aperiodic channel state information report in a mobile communication system,
A transmitting and receiving unit for transmitting and receiving signals to and from the terminal; And
CSI report trigger information and the non-periodic channel status information report for a multi-user channel status information report (MU-CSI report) And a control unit for controlling delivery of the periodic channel state information report indicator to the terminal. 14. The method of claim 13,
Wherein,
A periodic or non-periodic channel state information report reported to a base station, a channel state information report of another terminal except the terminal, or load information of a current base station. 14. The method of claim 13,
Wherein,
And determining whether to use the aperiodic channel state information reporting table. 14. The method of claim 13,
Wherein the MU-CSI report trigger information is an MU-PMI (Multi User-Precoding Matrix Indicator) determined by the BS. 14. The method of claim 13,
Wherein the MU-CSI report trigger information is a plurality of IMR (Interference Measurement Resource) determined by the BS. 17. The method of claim 16,
Wherein the MU-PMI is predetermined by the base station. 17. The method of claim 16,
Wherein the MU-PMI is determined based on a Single User-Precoding Matrix Indicator (SU-PMI) reported by the UE. A terminal for reporting channel state information in a mobile communication system,
A transmission / reception unit for transmitting / receiving signals to / from a base station; And
(MU-CSI report) trigger information and an aperiodic channel state information reporting indicator based on the MU-CSI report trigger information, and transmits the channel state information using the MU-CSI report trigger information And reporting the generated aperiodic channel state information to the base station based on the measured result. 21. The method of claim 20,
Wherein the MU-CSI report trigger information is an MU-PMI (Multi User-Precoding Matrix Indicator) determined by the BS. 21. The method of claim 20,
Wherein the MU-CSI report trigger information is a plurality of IMR (Interference Measurement Resource) determined by the BS. 22. The method of claim 21,
Wherein the MU-PMI is predetermined by the base station. 22. The method of claim 21,
Wherein the MU-PMI is determined based on a Single User-Precoding Matrix Indicator (SU-PMI) reported by the UE.

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