KR20160055086A - Method and apparatus for transmitting reference signal, method and apparatus for measuring and reporting channel state information, and method for configuring the same - Google Patents

Abstract

Provided is a method for allowing a base station to transmit a channel state information (CSI) - reference signal (RS) in a multiple input multiple output (MIMO) antenna system. The base station periodically transmits a CSI-RS for first CSI to a terminal. The base station requests the terminal to transmit second CSI in a first sub-frame. Also, the base station transmits a CSI-RS for the second CSI to the terminal during the duration of a CSI-RS occasion from a second sub-frame, which is a sub-frame after a first offset configured for the transmission of the CSI-RS from the first sub-frame, or to the second sub-frame if the CSI-RS occasion is configured.

Description

TECHNICAL FIELD [0001] The present invention relates to a method and apparatus for transmitting and receiving a reference signal, a method and apparatus for measuring and reporting channel state information, and a setting method for the same. THE SAME}

The present invention relates to a method and apparatus for transmitting a reference signal, a method and apparatus for measuring and reporting channel state information, and a setting method therefor.

A full-dimensional multiple input multiple output (MIMO) transmission is performed using a two-dimensional antenna array in a horizontal domain / direction (azimuth domain / direction) And adaptively forming a beam for a vertical domain / direction, a zenith domain / direction, or an elevation domain / direction (hereinafter referred to as a 'vertical domain'), , Cell coverage improvement, and so on.

For the FD-MIMO transmission, the base station or the repeater may use a rank indicator (RI), a channel quality indicator (CQI), a precoding matrix indicator (PMI), M (Or feedback) information on channel state information (CSI) including positions of selected subbands or preferred subbands (hereinafter referred to as " selected subbands & ').

Meanwhile, the UE must acquire a MIMO channel for CSI measurement. When a base station sets up a CSI-RS (reference signal) or a non-zero power (CSI-RS) and transmits CSI-RS according to the CSI-RS, the UE receives the CSI-RS and estimates a MIMO channel. The base station can set the energy per resource element (EPRE) of the CSI-RS in consideration of the channel estimation performance using the CSI-RS and the interference to adjacent cells due to the CSI-RS transmission. When the UE measures the various types of CSIs (e.g., RI, CQI, PMI, selected subband, etc.) using the channel estimated from the CSI-RS and reports it to the base station, And performs scheduling (or resource allocation). The CSI-RS transmission described below means that the base station transmits to the terminal, and may include the terminal receiving the CSI-RS from the base station. The CSI report described below means that the UE transmits the CSI measured by the BS to the BS, and may include the BS receiving the CSI from the UE. The 'current standard' referred to below refers to the current specification of the 3GPP (Long Term Evolution) Release 12 of the 3 ^rd generation partnership project (3GPP).

The CSI-RS is a downlink reference signal transmitted from a base station for the purpose of measuring a channel required for measuring a downlink CSI, and was introduced in 3GPP LTE Release 10. CSI-RS is also referred to as NZP CSI-RS for distinguishing from ZP (zero-power) CSI-RS to be described later. In 3GPP LTE Release 8/9 system, cell-specific reference signal (CRS) was used for CSI measurement of UE. However, since 3GPP LTE Release 10, in order to support downlink transmission of up to 8 layers, It is necessary to introduce a reference signal for a new channel estimation having a low density.

The CSI-RS is set to the UE through user equipment (UE) -specific radio resource control (RRC) signaling, and the number of CSI-RS antenna ports configurable to the UE is 1, 2, 4 and 8. The CSI-RS is transmitted in the entire system bandwidth, and two REs (resource elements) are used per PRB (physical resource block) pair for CSI-RS transmission of each CSI-RS antenna port. Two CSI-RS antenna ports are code division multiplexed (CDM) in two REs over two OFDM symbols separated by two consecutive orthogonal frequency division multiplexing (OFDM) symbols (or one OFDM symbol) of the same subcarrier , And a density of 1 RE / CSI-RS antenna port. The transmission period in the time axis of the CSI-RS may be set to 5, 10, 20, 40, or 80 ms. The mapping of the RE to which the CSI-RS is transmitted follows a pattern defined by a configuration parameter (CSI-RS configuration) for each antenna port number.

The CSI-IM (interference measurement) resource is a resource for the UE to measure the interference required for CSI measurement, and was introduced in 3GPP LTE Release 11. The RE location in the PRB pair for CSI-IM is referred to by the CSI-RS configuration configuration parameter corresponding to the number of four CSI-RS antenna ports. The transmission period in the time axis of CSI-IM may be set to 5, 10, 20, 40, or 80 ms, as in the case of NZP CSI-RS.

In the case where the UE performs physical downlink shared channel (PDSCH) rate matching, it is assumed that the PDSCH is not mapped to the RE set by the ZP CSI-RS. The ZP CSI-RS can be used for two purposes. First, the BS may attempt to improve the CSI-RS measurement performance of the UE for neighboring cells by not transmitting (or muting) the signal in the RE to which the CSI-RS of the neighboring cell is transmitted . In this case, the BS can inform the UE of the REs to which muting is applied through the ZP CSI-RS setting. Second, the ZP CSI-RS can be set for the purpose of setting a resource for measuring an interference signal of a terminal. The CSI-IM resource used for the measurement of the interference signal can be set only within the ZP CSI-RS resource region set for the UE.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and apparatus for transmitting a CSI-RS necessary for CSI measurement for FD-MIMO transmission.

Another object of the present invention is to provide a method and apparatus for measuring and reporting CSI using CSI-RS when receiving CSI-RS.

According to an embodiment of the present invention, there is provided a method for transmitting a channel state information (CSI) -reference signal (RS) in a multiple input multiple output (MIMO) antenna system. The CSI-RS transmission method of the base station includes: periodically transmitting a CSI-RS for a first CSI to a terminal; Requesting the terminal to transmit a second CSI in a first subframe; Frame from the first sub-frame to the second sub-frame, which is a sub-frame after the first offset set for the CSI-RS transmission from the first sub-frame, when the CSI-RS occasion is set, And transmitting the CSI-RS for the second CSI to the terminal during a duration of the RS-ACTION.

The first CSI may be a CSI for one of a horizontal domain and a vertical domain, and the second CSI may be a CSI for the remaining domains.

Wherein the step of requesting the terminal to transmit the second CSI comprises the step of transmitting the transmission of the second CSI to the terminal when it is determined that at least one of the update to the second CSI and the feedback to the second CSI is necessary And a requesting step.

The step of requesting transmission of the CSI-RS for the second CSI may include receiving a transmission request of the CSI-RS for the second CSI from the terminal in a third sub-frame; And requesting the terminal to transmit the second CSI in the first sub-frame that is a sub-frame after the second offset set for the CSI-RS transmission from the third sub-frame.

The receiving of the CSI-RS transmission request for the second CSI may include receiving a CSI for the second CSI through at least one of a physical uplink control channel (PUCCH) and a control element (MAC) And receiving a transmission request of the RS from the terminal.

The CSI-RS transmission request for the second CSI includes at least one of a reference signal received power (RSRP), a received signal strength indicator (RSSI), a reference signal received quality (RSRQ) The value or the degree of change of the value is equal to or greater than the threshold value.

The step of transmitting the CSI-RS for the second CSI may include transmitting the CSI-RS for the second CSI in a subframe where the CSI-RS for the first CSI is transmitted, And setting a CSI-RS transmission resource for the second CSI so as not to overlap CSI-RS transmission resources for the second CSI.

The method of establishing the base station may further comprise establishing interworking information between the periodic CSI report of the MS and the aperiodic CSI report of the MS to the MS through signaling between the BS and the MS.

The CSI measurement for the aperiodic CSI reporting of the terminal may be performed by the terminal that has received the crosstalk information based on the CSI measurement for periodic CSI reporting of the terminal.

According to another embodiment of the present invention, there is provided a method for a BS to measure and report channel state information (CSI) in a multiple input multiple output (MIMO) antenna system. The method of establishing a base station includes: grouping a plurality of CSI-RS antenna ports into a plurality of CSI-RS antenna port groups; RS antenna port group to a subscriber station (DSI) when requesting a CSI report of a first CSI-RS antenna port group among the plurality of CSI-RS antenna port groups to the subscriber station, Into a CSI request field of a downlink control information (DCI) format; And requesting the UE for an aperiodic CSI report using the CSI request field of the DCI.

The method of claim 1, wherein, when requesting a CSI report of at least one of a horizontal domain and a vertical domain to the UE, the information corresponding to the at least one domain is transmitted to the CSI request field of the DL DCI format The method comprising:

The method of establishing the base station may further comprise the steps of: when the terminal desires to measure a second domain CSI based on a first domain CSI of a first domain CSI and a second domain CSI, Setting the first CSI process as a reference CSI process among a process and a second CSI process for the second domain CSI; And notifying the terminal of the process identifier indicating the first CSI process as information of the reference CSI process.

The first domain CSI may be one of a horizontal domain CSI and a vertical domain CSI, and the second domain CSI may be one of the horizontal domain CSI and the vertical domain CSI.

Wherein setting the first CSI process as a reference CSI process comprises: setting the reference CSI process for a first set of CSI measurement subframes to the UE; And setting the second CSI process for the plurality of second CSI measurement subframe sets to the UE.

Wherein the second domain CSI for the plurality of second CSI measurement subframe aggregates is measured by the terminal on the basis of the first domain CSI for the first set of measured subframes measured through the reference CSI process .

The step of configuring the first CSI process as a reference CSI process may include setting the reference CSI process and the second CSI process for a plurality of CSI measurement subframe sets to the UE.

Wherein the second domain CSI for each of the plurality of CSI measurement subframe sets is measured by the terminal on the basis of the first domain CSI for each of the plurality of CSI measurement subframe aggregates measured through the reference CSI process .

According to another aspect of the present invention, there is provided a method for a base station to set up a process of channel state information (CSI) in a multiple input / multiple output (MIMO) antenna system. The method of establishing the base station may include configuring a plurality of CSI-RS resource configurations when operating in a first CSI-RS mode in which a plurality of CSI-RS (reference signal) antenna ports have the same beam width and beam direction, (CSI-IM) resource configuration in a first CSI process configuration information, wherein the first CSI process configuration information includes a first identifier and a second identifier indicating a CSI-IM (interference measurement) resource configuration; Setting the first CSI process configuration information to the terminal; And receiving, from the terminal, the measured CSI according to the first CSI process configuration information.

Wherein a number of a plurality of CSI-RS antenna ports included in a plurality of CSI-RS resources corresponding to the plurality of first identifiers is included in the first CSI process setting information by the terminal Order or the values of the first identifiers.

The method of establishing the base station includes the steps of: when a plurality of CSI-RS antenna ports are operated in a second CSI-RS mode in which all or part of the CSI-RS antenna ports have different beam directions, Including a third identifier and a plurality of fourth identifiers indicating a plurality of CSI-IM resource configurations in one second CSI process configuration information; Setting the second CSI process configuration information to the terminal; And receiving the measured CSI from the terminal according to the second CSI process configuration information.

The method of establishing the base station may include: selecting one of the first CSI-RS mode and the second CSI-RS mode; And including information indicating the selected mode in the setting information corresponding to the selected mode among the first CSI-RS process setting information and the second CSI-RS process setting information.

RS mode, Doppler shift, Doppler spread, and Doppler spread between the first CSI-RS antenna port and the DM (demodulation) -RS antenna port of the plurality of CSI-RS antenna ports, the UE can assume that a quasi co-location (QCL) for a spread, an average delay, and a delay spread is satisfied.

The first CSI-RS antenna port may be a CSI-RS antenna port belonging to a CSI-RS resource indicated by a first identifier selected by the terminal among the plurality of third identifiers.

RS mode, a Doppler shift, a Doppler spread, an average delay, and a delay spread between a first CSI-RS antenna port and a first DM-RS antenna port of the plurality of CSI- The UE can assume that the QCLs for up to four QCLs are satisfied.

The first CSI-RS antenna port may be configured to transmit, to a CSI process corresponding to QCL information set by physical layer signaling from the base station for PDSCH (physical downlink shared channel) reception, And may be a CSI-RS antenna port belonging to a CSI-RS resource indicated by a third identifier selected by the terminal.

The first DM-RS antenna port may be a DM-RS antenna port belonging to the PDSCH transmission resource allocated by the DL DCI format including the QCL information.

Each of the plurality of third identifiers and each of the plurality of fourth identifiers may be paired according to an order included in the second CSI process setting information.

The UE measures channels for a plurality of beams using CSI-RSs of a plurality of CSI-RS antenna ports corresponding to the plurality of third identifiers, Measuring interferences for the plurality of beams at a resource defined for a plurality of CSI-RS antenna ports corresponding to a fourth identifier, selecting at least one of the plurality of beams using the measured channels and interferences, The CSI for each of the selected beams can be measured.

Wherein the step of receiving the measured CSI in accordance with the second CSI process setting information comprises: comparing a third identifier corresponding to the selected one of the plurality of third identifiers, for a selected beam, Receiving from the terminal together with CSI; And receiving a bitmap representing a third identifier corresponding to the selected one of the plurality of third identifiers from the terminal along with the CSI for the selected beam if the selected beam is multiple have.

According to an embodiment of the present invention, a method and apparatus for transmitting CSI-RS for FD-MIMO transmission using multiple antennas, and a method and apparatus for measuring and reporting CSI using the CSI-RS can be provided .

Also, according to the embodiment of the present invention, the CSI-RS can be efficiently transmitted considering the overhead, the system performance, the two-dimensional antenna array structure and the channel characteristics thereof, and the CSI can be effectively measured and reported.

Further, according to the embodiment of the present invention, system performance of FD-MIMO can be improved.

1A, 1B, and 1C are diagrams illustrating a method for transmitting a CSI-RS in conjunction with a CSI request according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a method of reporting CSI by linking a periodic CSI report and an aperiodic CSI report according to an embodiment of the present invention.
3A and 3B are diagrams illustrating a CSI measurement restriction method applied to a time domain according to an embodiment of the present invention.
4 is a diagram illustrating a base station according to an embodiment of the present invention.
5 is a diagram illustrating a terminal according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, a terminal is referred to as a mobile terminal (MT), a mobile station (MS), an advanced mobile station (AMS), a high reliability mobile station ), A subscriber station (SS), a portable subscriber station (PSS), an access terminal (AT), a user equipment (UE) MS, AMS, HR-MS, SS, PSS, AT, UE, and the like.

In addition, the base station (BS) includes an advanced base station (ABS), a high reliability base station (HR-BS), a node B, an evolved node B an eNodeB, an access point, a radio access station (RAS), a base transceiver station (BTS), a mobile multihop relay (MMR) -BS, a relay node BS, ABS, HR-BS, Node B, eNodeB, and so on), a high reliability relay station (HR-RS), a repeater, access point, RAS, BTS, MMR-BS, RN, HR-RS, repeater, macro base station, small base station and the like.

1. Two-Dimensional Antenna Array Virtualization Method

The CSI items that the UE measures and reports to the base station may include RI, PMI, CQI, and selected subband index (s). In general, when a base station transmits a signal (or a physical channel, hereinafter referred to as a " signal ") to a mobile station, a MIMO channel experienced on the radio has a row corresponding to the number of reception antennas of the mobile station and a number of transmission antennas Can be expressed as a matrix. The i-th row and j-th column component of the MIMO channel matrix means a channel value between an i-th receiving antenna (or an antenna element) and a j-th transmitting antenna (or an antenna element, a radiation element).

The base station includes an antenna element (or radiation element) (hereinafter referred to as an 'antenna component') and an antenna port (AP), which is a logical multiple input unit of a baseband for signal transmission, ), There can be two virtualization processes.

The signal of each antenna port is input to a single or a plurality of transceiver units (TXRU) through an antenna port virtualization process, and is processed in a TXRU process. The signal of each TXRU processed in this manner is input into a single or a plurality of antenna components (or a unit including an antenna component, hereinafter, referred to as an 'antenna component') through a TXRU virtualization process. The signals processed up to the respective antenna components propagate through the wireless channel.

As an example of an antenna port virtualization method, a signal having a magnitude and / or phase is multiplied by a signal of each antenna port or a plurality of antenna ports, and a signal obtained by summing the signals of the respective antenna ports multiplied by the weight value is input to the TXRU There is a way. Where the signal of the antenna port can be virtualized into a single or multiple TXRUs, and one TXRU can be output from a single or multiple antenna ports and then receive a virtualized signal.

As an example of the TXRU virtualization method, a method of multiplying a single or a plurality of TXRU output signals by a weight value having a magnitude and / or phase, and inputting a signal obtained by summing output signals of each TXRU multiplied by the weight value to an antenna component have. Here, the output signal of TXRU may be virtualized into a single or a plurality of antenna components, and one antenna component may be output from a single or multiple TXRUs and then receive a virtualized signal.

Each antenna port is virtualized to each antenna element and transmitted to the terminal. Each antenna port can form a beam in a specific direction through virtualization. According to the virtualization method, it is possible to form beams of all the antenna ports in the same direction, to form all the beams of all the antenna ports in different directions, or to form the same beam only between some antenna ports. In consideration of an effective MIMO channel in which an antenna port of a base station is input and an output of a terminal is a receive antenna (or a receive antenna port, hereinafter referred to as a receive antenna) in the baseband, beamforming or free Precoding is performed. If different virtualizations are applied, the radio channels are the same, but the effective MIMO channels in the baseband may have different values.

The virtualization method described above may include the following two methods (method M100, method M101).

Method M100 is a virtualization method in which each antenna port has different transmit vertical and / or different transmit horizontal directions. Here, the vertical direction can be replaced with a zenith angle, an elevation angle, a vertical angle, or a tilting angle, and a horizontal direction can be replaced with an azimuth angle, a horizontal angle, or a bearing angle.

Method M101 is a virtualization method in which all antenna ports have the same transmit vertical direction and / or the same transmit horizontal direction.

CSI-RS AP 2 > CSI-RS AP 3과 같은 순서를 가질 수 있다. 해당 단말을 위해서는 기지국이 CSI-RS AP 1을 통해 신호를 전송하는 것이 효율적일 수 있다. 반면에, 방법 M101은, 각 안테나 포트가 동일한 송신 방향을 갖도록 가상화하므로, 단말이 수신하는 각 안테나 포트의 신호 크기 차이는 작을 수 있다. 따라서 방법 M101은, 모든 안테나 포트를 이용하여 빔을 형성하는 전송 방법에 적합하다.The method M100 virtualizes each antenna port to have different transmit vertical and / or different transmit horizontal directions (hereinafter referred to as 'transmit vertical direction and / or transmit horizontal direction' as 'transmit direction'), The difference in magnitude of the signal received from the antenna port may be large. Therefore, the method M100 is suitable for the case where a beam is formed using a part of antenna ports having a large reception signal size, or when each antenna port corresponding to candidate beams is transmitted so that the terminal can select an optimum beam. For example, assuming that the base station configures four antenna ports in the vertical domain, the signal size of each CSI-RS antenna port (hereinafter, referred to as 'CSI-RS AP') received by any one terminal is CSI-RS AP 1 > CSI-RS AP 0

CSI-RS AP 2 > CSI-RS AP 3. It may be efficient for the base station to transmit the signal through the CSI-RS AP 1 for the corresponding terminal. On the other hand, the method M101 virtualizes each antenna port to have the same transmission direction, so that the signal size difference of each antenna port received by the terminal may be small. Thus, method M101 is suitable for a transmission method of forming a beam using all antenna ports.

On the other hand, the above-described virtualization methods (e.g., method M100, method M101) can be UE-specific or UE-group-specific.

Meanwhile, the above-described virtualization method can be used transparently from a terminal perspective. That is, the UE can perform a series of processes such as CSI-RS reception and channel estimation, CSI measurement and reporting, and PDSCH reception, regardless of whether or not virtualization is applied.

2. CSI-RS transmission, setting method, and other related methods

As described above, in order for the UE to acquire the channel between each antenna port of the base station and the Rx antenna, it must receive the CSI-RS transmitted by the base station and estimate the channel therefrom. At this time, the terminal estimates a channel from an antenna port set by the base station to the CSI-RS AP among the antenna ports that can be set by the base station, measures the CSI using the channel, and reports the CSI to the base station. For example, assume that a base station can configure four antenna ports from a base station perspective. When the base station sets up only two antenna ports to the terminal A1 as a CSI-RS AP and transmits a signal, the terminal A1 estimates a channel for two CSI-RS APs and can perform CSI measurement and reporting using the channel. If the base station transmits a signal by setting all four antenna ports to the CSI-RS AP to the terminal B 1, the terminal B 1 estimates a channel for four CSI-RS APs and can perform CSI measurement and reporting using the channel estimation .

On the other hand, when the base station has a large number of antenna ports, the beam can be finely formed, thereby alleviating intra-cell interference and inter-cell interference, thereby improving system performance . However, since the base station must increase the number of CSI-RS APs accordingly, the number of resources (or REs) that can transmit data can be reduced, thereby reducing the degree of system performance improvement. Therefore, a CSI-RS transmission method is needed to reduce the overhead of the CSI-RS while maintaining the accuracy of the CSI reported by the base station. In addition, a CRS, a UE-specific reference signal (UE-RS), a DM-RS (demodulation reference signal), a PRS (demodulation reference signal), and the like, which are used in the current 3GPP LTE Release 12 specification (including 3GPP LTE Release 8 standard to 3GPP LTE Release 12 specification) a control channel region including a positioning reference signal, a multicast broadcast single frequency network (MBSFN) RS, a physical control format indicator channel (PCFICH), a physical downlink control channel (PDCCH), and a physical hybrid- it may not be possible to allocate a large number of additional CSI-RS resources (or REs) to one transmission time interval (TTI) or subframe, avoiding the RE corresponding to the control channel region, A transmission method is required.

(Hereinafter referred to as " CSI-RS subframe " in which a signal of a CSI-RS AP is transmitted is referred to as a " CSI-RS subframe ") in which a signal of a CSI- The CSI-RS transmission method may include the following method (method M200, method M201).

Method M200 is a method of transmitting signals of all CSI-RS APs in one CSI-RS subframe. The method M201 groups the CSI-RS APs and transmits signals of the CSI-RS APs belonging to each CSI-RS AP group (hereinafter, referred to as 'CSI-RS APG') in different CSI-RS subframes for each CSI-RS APG Method.

In method M201, the size of each CSI-RS APG (or CSI-RS AP subset, hereinafter collectively referred to as CSI-RS APG) may be different. Also in method M201, a CSI-RS AP belonging to all CSI-RS APGs may not constitute all CSI-RS APs. In such a case, method M201 may include method M201-1A.

The method M201-1A includes a CSI-RS APG for CSI-RS APs for antenna ports belonging to one row listed in a horizontal domain, a CSI-RS AP for antenna ports belonging to a column listed in a vertical domain, RS APG, and transmits the CSI-RS. In the CSI-RS setting method for method M201-1A, when the base station sets each CSI-RS APG, antenna port array domain information including at least a horizontal domain and a vertical domain is transmitted To be included in higher-layer signaling.

The method M201 may include the following two methods (method M201-2A, method M201-2B) as the CSI-RS setting method.

The method M201-2A is a method of setting a plurality of CSI-RS APGs using a plurality of CSI processes. Method M201-2B is a method of setting a plurality of CSI-RS APGs using a CSI-RS occasion.

Method M201-2A uses CSI-RS-ConfigNZP (or NSI CSI-RS resource configuration ID) corresponding to csi-RS-ConfigNZPId (or NZP CSI-RS resource configuration ID) of each CSI process using a plurality of CSI processes supported by the base station RS APs belonging to each CSI-RS APG through the NZP CSI-RS resource configuration.

When method M201-1A is set using method M201-2A, two CSI processes are set up. One CSI process of two CSI processes may establish a CSI-RS APG for the horizontal domain and a CSI-RS APG for the vertical domain using the NZP CSI-RS of another CSI process. If method M201-2A is used for method M201-1A, the array domain information of the corresponding NZP CSI-RS APs may be included in CSI-Process IEs or CSI process setup information, Domain, and vertical domain. For measurement and reporting of the CSI assuming that the PDSCH is transmitted through the NZP CSI-RS APs corresponding to all or part of the CSI processes among the plurality of CSI processes, the association / association information between the CSI processes is CSI Process or CSI-RS configuration. The terminal can use this information to simultaneously or interdependently measure the CSI for the associated plurality of CSI processes. For example, when setting up the CSI-RS for method M201-1A, the base station can set the linkage for two CSI processes corresponding to horizontal and vertical domains using linkage information. On the other hand, the base station may determine that the csi-IM-ConfigId (or the csi-IM-ConfigId) for multiple CSI processes so that a plurality of CSI processes have the same CSI-IM settings so that interference to a plurality of associated CSI processes can be measured in an equivalent situation (Or a CSI-IM resource configuration ID) corresponding to a CSI-IM having the same CSI-RS subframe configuration to a plurality of CSI processes Can be set.

In method M201-2B, in order to allow one CSI-RS resource setting to be performed for a plurality of CSI-RS APGs, a discovery reference signal (DRS) setting concept applied to a small cell enhancement (SCE) is borrowed . For convenience of explanation, this is referred to as CSI-RS setting. The CSI-RS assignment setting may include at least a respective CSI-RS subframe setting in which a plurality of CSI-RS APGs can be transmitted. In addition, the CSI-RS allocation setting may further include the cycle and offset information and the CSI-RS resource allocation in which the CSI-RS allocation is repeated. In addition, the CSI-RS APG setting, the CSI-RS APG number, the CSI-RS APG ID of each CSI-RS APG, the CSI-RS APG number, the CSI- Transmission resources, the array domain information described in method M201-2A. Additionally, the CSI-RS occasion configuration may further include a CSI-IM resource configuration or a CSI-IM resource configuration ID (e.g., csi-IM-ConfigId) for interference measurement in the CSI-RS operation.

On the other hand, a method in which an antenna port to which virtualization is applied so as to have different transmission directions transmits CSI-RS may include the following method (method M210, method M211).

The method M210 is a method in which a base station transmits a signal of a CSI-RS AP for all antenna ports in each CSI-RS subframe regardless of a transmission direction. The method M211 is a method in which a base station transmits signals of a CSI-RS AP to antenna ports having the same transmission direction in the same CSI-RS subframe.

In method M210, the base station transmits a signal of the CSI-RS AP for all antenna ports in each CSI-RS subframe regardless of the transmission direction. For example, a base station configures four antenna ports (eg, antenna ports 0 through 3), virtualizes antenna ports 0 and 1 to have a tilting angle of 102 degrees, and antenna ports 2 and 3 have a tilting angle of 90 degrees Assume that virtualization. In this case, according to method M210, the signals of the four CSI-RS APs in the CSI-RS subframe may be transmitted together.

The method M211 is a method in which only the antenna ports having the same transmission direction transmit signals of the respective CSI-RS APs in the same CSI-RS subframe. If the same assumption as in the method M210 described above is applied to the method M211, the CSI-RS for antenna ports 0 and 1 is transmitted through two CSI-RS APs in one CSI-RS subframe, And 3 are transmitted through two CSI-RS APs in another CSI-RS subframe.

A method of transmitting signals of antenna ports having different transmission directions according to the method M211 in different CSI-RS subframes may include the following two methods (method M211-1A, method 211-1B).

The method M211-1A is a method in which a base station sets CSI-RS subframe configurations as many as the number of transmission directions and transmits a signal of the CSI-RS AP in the transmission direction in the corresponding CSI-RS subframe.

The method M211-1B is a method in which a base station sets one CSI-RS subframe configuration and transmits CSI-RS by applying different virtualization according to a corresponding transmission direction in each CSI-RS subframe. Method M211-1B can be divided into the following two methods (method M211-1B-1, method M211-1B-2) depending on whether the base station transmits virtualization setting information to the terminal.

Method M211-1B-1 is a method in which a base station uses virtualization without virtualization setting information for the terminal. Method M211-1B-2 is a method in which the base station notifies the terminal of virtualization setting information and uses virtualization.

In method M211-1B-2, the base station can define a virtualization pattern in notifying the terminal of virtualization setting information. Here, the virtualization pattern may include information indicating a virtualization weight applied to each CSI-RS subframe or information indicating a transmission direction according to virtualization. In order to define a virtualization pattern, a base station uses a virtualization indicator (VI) applied to each CSI-RS subframe for CSI-RS subframes corresponding to a corresponding number of CSI-RS subframes and length information, . The base station can set the virtualization pattern information through the high-layer signaling and / or the physical layer signaling to the terminal, and can change and reset the virtualization pattern information. In order to reduce the signaling overhead when the base station resets the virtualization pattern information, a set of virtualization patterns configured with a predetermined number of virtualization patterns may be defined and only the indicator (or identifier) of the virtualization pattern may be transmitted. The base station may include in the virtualization pattern aggregation information at least a virtualization pattern aggregation size, a virtualization pattern aggregation size of the virtualization pattern aggregation size (which may be the CSI-RS subframe count), and a virtualization pattern indicator.

The CSI-RS transmission method according to the periodicity or instantiability of the CSI-RS transmission may include the following three methods (method M220, method M221, method M222).

The method M220 is a method by which the base station periodically transmits the CSI-RS. The method M221 is a method in which the base station transmits the CSI-RS in a momentary manner. In the instantaneous transmission of the CSI-RS by the base station, the instantaneousness may correspond to the terminal viewpoint. In other words, even if the base station periodically transmits the CSI-RS in the system viewpoint, the base station can set the CSI-RS such that the corresponding CSI-RS is instantaneously transmitted from the viewpoint of one terminal.

The method M222 is a method in which the base station periodically transmits the CSI-RS and further transmits the CSI-RS in a momentary manner as necessary.

In the present specification, a base station sets a CSI-RS subframe configuration including a CSI-RS transmission period and an offset to each UE through high-layer signaling, and periodically transmits the CSI-RS. This corresponds to a method combining method M200 and method M220 (hereinafter referred to as " method M220-1A ").

A method combining method M201 and method M220 (hereinafter referred to as method M220-1B) may also be used. If the application of method M201-2B is considered for method M201, the BS may set the period and offset information for the CSI-RS operation to the MS through the high-layer signaling, RS APGs belonging to the corresponding CSI-RS APG in each CSI-RS subframe in the CSI-RS allocation. If method M201-2A is considered for method M201, the BS can set the transmission period and offset of the corresponding CSI-RS through the CSI-RS subframe configuration of the NZP CSI-RS configuration belonging to each CSI process have. Here, the base station may set different transmission periods of the CSI-RS APG through the NZP CSI-RS setting belonging to each CSI process. For example, the base station may set the transmission period of the horizontal domain CSI-RS APG to be shorter than the transmission period of the vertical domain CSI-RS APG in order to reduce the overhead due to the CSI-RS transmission.

The method M221 may include the following two methods (method M221-1A, method M221-1B) as a method for the base station to transmit the CSI-RS momentarily. Method M221-1A is a method in which a base station transmits a CSI-RS in conjunction with a base station's CSI request. The method M221-1B is a method in which a base station transmits a CSI-RS by a CSI-RS transmission request of the terminal.

Referring to Figs. 1A, 1B, and 1C, a method M221-1A is described. Specifically, FIG. 1A shows a case where CSI-RS is set in one CSI-RS subframe. 1B shows a case where a CSI-RS is set up and a CSI-RS is transmitted from a base station to N consecutive DL subframes (including (n1 + k1) th DL subframe) starting from the (n1 + Fig. 1C shows a case where a CSI-RS is set and a CSI-RS is transmitted in N consecutive DL subframes (including (n1 + k1) th DL subframes) up to the (n1 + Fig.

The BS transmits a CSI-RS associated with a CSI request from the (n1 + k1) th DL subframe to the (n1 + k1) th subframe when transmitting the CSI request to the mobile station in the n1-th DL subframe . Where k1 is an integer greater than or equal to zero and may be predefined or set via higher-layer signaling.

Meanwhile, when the CSI-RS is set in one CSI-RS subframe as illustrated in FIG. 1A, the base station can transmit the CSI-RS in the (n1 + k1) th DL subframe. For example, as illustrated in FIG. 1A, when a base station transmits a CSI request to a mobile station in an (n1) th DL sub-frame, it transmits a CSI-RS in an (n1 + k1) th sub-frame.

Meanwhile, as illustrated in FIGs. 1B and 1C, when a plurality of CSI-RS subframes of the CSI-RS option are set and a plurality of CSI-RS subframes are required for a plurality of CSI processes 1b) or (n1 + k1) th DL subframes (Fig. 1 (c)) in the case where there is a need for a base station other than the (n1 + Lt; RTI ID = 0.0 > CSI-RS. ≪ / RTI > Where N is an integer greater than or equal to 1. For example, as illustrated in FIG. 1B, when a base station transmits a CSI request to a mobile station in an n1-th DL sub-frame, the base station transmits a (n1 + k1 + CSI-RS to the frame. 1C, when the base station transmits a CSI request to the UE in the n1-th DL sub-frame, the base station transmits the CSI request from the (n1 + k1-N + 1) And transmits the CSI-RS to the subframe.

The base station can signal the CSI request to the terminal through the CSI request field of the DL downlink control information (DCI) format. The UE receiving the CSI request transmits the DL subframe from the (n1 + k1) th subframe (FIG. 1A) to the (n1 + k1) RSs are received in N consecutive DL sub-frames (FIG. 1C) up to the sub-frame, and the CSI for reporting Aperiodic CSI corresponding to the corresponding CSI request can be measured using the received CSI-RS. Here, the terminal may assume that the CSI-RS associated with the CSI request is transmitted in the corresponding DL subframe (s) only when there is a CSI request. The time interval (or time domain measurement window) for the corresponding CSI measurement may be determined based on the number of DL subframes (or time slots) in which the CSI-RS corresponding to the CSI request is transmitted ). ≪ / RTI > The base station transmits, to the CSI-RS transmission associated with the CSI request, the RRC signaling parameter of the CSI-RS setting (CSI-RS setting for the transmission mode 9) and / or the RRC signaling parameter of the CSI process setting, -RS Whether to allow transmission or not can be included. A CSI-RS subframe configuration including a period and an offset may be set for the NZP CSI-RS included in the CSI-RS setting or the CSI process setting so that periodic transmission is possible. However, when the CSI-RS transmission permission is not always transmitted in the corresponding CSI-RS subframe but the CSI request (for example, in the n1 < th > (n1 + k1) th DL subframe from the (n1 + k1) th DL subframe to the N consecutive DL subframes (Fig. 1B) If the DL subframe (FIG. 1C) is a CSI-RS subframe, it is assumed that the CSI-RS is transmitted, and the channel can be measured using the CSI-RS.

The method M221-1B is a method in which the base station transmits the CSI-RS according to the CSI-RS transmission request of the terminal. Specifically, when the base station receives the CSI-RS transmission request in the (n2) th UL subframe from the terminal, it transmits a CSI request to the terminal in the (n2 + k2) -RS. Here, k2 is an integer greater than or equal to 0 and is defined in advance. In frequency division duplexing (FDD), it can be defined as one value. In time division duplexing (TDD), another value is defined according to UL / DL configuration . The UE can transmit CSI-RS transmission request information to the BS through a physical uplink control channel (PUCCH) or a medium access control (CE) control element (CE). To this end, the existing PUCCH format or MAC CE format may be used or these may be newly defined. The MS may request the CSI-RS transmission to the BS including the CSI-RS APG information required to be received. When the CSI-RS is set using the above-described CSI-RS access information, the CSI-RS APG information may include a CSI-RS APG ID of the corresponding CSI-RS APG or a plurality of CSI- And a CSI-RS APG ID list indicating RS APG IDs. When the CSI-RS is set using the above-described multiple CSI process, the CSI-RS APG information includes a CSI process ID of a CSI process corresponding to the corresponding CSI-RS APG or a CSI process ID of a CSI process ID It may contain a list of process IDs. An example related to the CSI-RS transmission request of the terminal is described in the following method M222.

Method M222 is a combination of method M220 and method M221. For example, the base station periodically transmits the CSI-RS to the UE in order to update the previously reported CSI or to receive feedback on the additional CSI items, The CSI-RS necessary for the CSI measurement can be transmitted to the UE. In another example of the combination of method M220 and method M221-1A, the base station periodically transmits a CSI-RS corresponding to the horizontal domain for CSI reporting on the horizontal domain, and the base station updates the CSI for the vertical domain If it is determined to be necessary, the terminal may request the CSI for the vertical domain and transmit the CSI-RS corresponding to the vertical domain.

For the combination of method M220 and method M221-1B, the method by which the terminal triggers a CSI-RS transmission request is based on a reference signal received power (RSRP), a received signal strength indicator (RSSI), a reference signal received quality (RSRQ) A method of comparing each Metric value with each corresponding threshold value or comparing the degree of change of each value with respect to any one or more combinations of CQI or comparing the degree of change of each value with a threshold value can do. For example, when the CSI-RS for the vertical domain is transmitted aperiodically and the CSI-RS for the horizontal domain is periodically transmitted, the terminal calculates the vertical domain CSI-RS from the most recently received vertical domain CSI- The CSI for the joint domain considering both the vertical and horizontal domains can be measured using the CSI-RS for the horizontal domain. In this case, when the difference between the measured CQI and the previously reported CQI is equal to or higher than a predetermined level, the UE requests the base station to transmit the CSI-RS for the vertical domain in order to update the CSI for the vertical domain.

Meanwhile, the method M222 may include the following methods (method M222-1A, method M222-1B) to prevent collision between periodic CSI-RS transmission and instantaneous CSI-RS transmission. Method M222-1A is a method in which a base station does not transmit an instantaneous CSI-RS in a CSI-RS subframe in a CSI-RS of a periodic CSI-RS. The method M222-1B is a method for setting an instantaneous CSI-RS transmission resource of the CSI-RS so that the base station does not overlap the CSI-RS transmission resource of the periodic CSI-RS.

On the other hand, for CSI-RS transmission and setting, any of a plurality of the above-described methods may be combined.

3. CSI measurement and reporting, how to set them up, and other related methods

The process of CSI measurement and reporting of the terminal is as follows. The terminal receives the CSI-RS according to the CSI-RS setting of the base station, and estimates the channel from each CSI-RS AP. The UE measures CSI (including RI, PMI, or CQI) using the estimated channel, and transmits the measured CSI through a PUCCH or a physical uplink shared channel (PUSCH) at the reporting time.

In the CSI measurement and reporting for a two-dimensional antenna array, the CSI reporting overhead can be significantly increased due to an increase in the number of antenna ports, and an efficient CSI reporting method considering the antenna array configuration and the channel characteristics is required. In addition, the CSI report may differ depending on the CSI-RS transmission method.

The CSI measurement method may include the following two methods (method M300, method M301) according to the classification of the spatial domain. Method M 300 is a method in which a terminal divides CSI into a vertical domain CSI (hereinafter, referred to as 'vCSI') and a horizontal domain CSI (hereinafter referred to as 'hCSI'). The method M301 is a method in which a UE measures a joint domain CSI (hereinafter, referred to as 'jCSI') without discriminating a spatial domain.

In method M300, vCSI may include a vertical domain PMI ('vPMI'), a vertical domain RI ('vRI'), and a vertical domain CQI ('vCQI'). The vCSI may be implemented on behalf of the vPMI by means of an NZP CSI-RS resource indicator (or NZP CSI-RS resource) corresponding to VI, Vertical Domain Beam Indicator (Vertical Domain Beam Index, Vertical Domain Beam ID, hereinafter referred to as 'Beam Indicator' configuration ID). The UE can obtain all the items of vCSI using the channel estimated from the vertical domain CSI-RS APs, or all, some, or one of the CSI-RS APs Can be obtained by using the estimated channel of the CSI-RS AP corresponding to the column.

In RI, vRIs can be excluded from vCSI reporting where measurement and reporting are restricted (rank restriction) to only one rank at a time.

For CQI, vCQI can be excluded from the vCSI report if only CQIs considering both vCSI and hCSI are reported.

In hCSI, except that the terminal uses an estimated channel of CSI-RS APs corresponding to all, some, or one row of CSI-RS APs arranged in the horizontal domain among all CSI-RS APs , the above matters concerning vCSI can be equally applied to hCSI.

The base station can receive vCSI and hCSI from the terminal, respectively, and use it to derive jCSI. The joint domain RI (hereinafter 'jRI') can be defined as the product of vRI and hRI. The joint domain precoding matrix may be defined as a Kronecker product of a precoding matrix corresponding to vPMI and a precoding matrix corresponding to hPMI. The joint domain CQI ('jCQI') can be defined as the sum of vCQI and hCQI on the dB (or Log) scale, or can be defined as the product of vCQI and hCQI on a linear scale.

In method M300, hCSI can be measured based on vCSI. Specifically, the terminal can measure and report hCSI based on previously measured and / or reported vCSI. For example, when the UE has set CSI-RS for all antenna ports used by the base station for data transmission, it can determine the hPMI based on the predetermined (acquired) vRI and the vPMI vRI ^* and vPMI ^* . To this end, for a given hRI and each candidate hPMI, the terminal considers the Kronecker product of two precoding matrices corresponding to hPMI and vPMI ^* as a joint precoding matrix and uses this together with the channel estimated from the CSI-RS to determine the PMI selection metric (Metric), and the PMI selection metric can be used to select an hPMI that meets the optimal criteria.

In selecting the hRI, the terminal can calculate the RI metric by constraining the vRI and the vPMI based on the predetermined vRI ^* and vPMI ^* , and select the hRI that meets the optimal criteria. Let hRI be the selected hRI ^* . Alternatively, the UE obtains the jRI using only the estimated channel (the jRI thus obtained is referred to as jRI ^* ), and the hRI can be obtained by dividing the jRI ^* by vRI ^* . Let hRI be the obtained hRI ^* .

On the other hand, vRI ^* can be replaced with a previously constrained value without making a decision. Instead hCQI is, hCQI measured considering only hRI hPMI ^* and ^* in this case ^{hCSI, vRI *, vPMI *,} hRI *, and can be replaced in both the hPMI ^* a jCQI measured in consideration.

On the other hand, vCSI can be measured based on hCSI, as opposed to the method in which the terminal measures hCSI based on vCSI. In such a case, vCSI is measured by a method in which hCSI and vCSI are exchanged in the above-described method. When a base station can set one of the above two methods (a method of measuring hCSI based on vCSI and a method of measuring vCSI based on hCSI), the base station transmits one of two methods to the mobile station, So that the terminal can perform the CSI measurement. Alternatively, the base station can set the CSI of the other domain based on a certain spatial domain to the UE through CSI-RS setting and / or CSI report setting.

The vPMI and the hPMI are classified into a wideband vPMI, a svPMI, a wideband hPMI, and a shPMI, respectively, depending on a measurement resource unit. wvPMI and whPMI mean the PMI measured in consideration of the CSI-RS of the full band, and svPMI and shPMI mean the PMI measured in consideration of the CSI-RS of the corresponding subband divided by the full band.

Meanwhile, when the terminal obtains the vRI, the vPMI, the hRI, and the hPMI, the base station can set the codebook subset restriction defined in the current specification for each domain. Obtain the measured values except for the RI and PMI values.

In method M301, jCSI may include RI, PMI, and CQI obtained by simultaneously considering the channel of the antenna port for the two domains by the UE. In the present specification, a terminal performs CSI measurement and reporting in the form of jCSI.

The UE measures CSI suitable for the CSI reporting mode set for vCSI, hCSI, and / or jCSI described above in the CSI reference resource. CSI reference in the current standard resources, is defined as the terminal is located in the case of transmitting the CSI reported by the n3-th sub-frame UL, (n3-n _{CQI _ ref)} the first DL sub-frame. For periodic CSI reporting, which will be described later _{_} n _{CQI ref} is gateumyeonseo typically 4 or greater than or equal to 5, is defined as the minimum value corresponding to a valid DL subframe. The n _{CQI_ref} for aperiodic CSI reporting is defined such that the CSI reference resource is located in a valid DL subframe in which the UE receives a UL DCI format CSI request from the base station. This may only be appropriate if all CSI-RS APs for CSI measurements are transmitted in one CSI-RS subframe. As described above, CSI-RS AP plurality of CSI-RS so that when the divided transmission in the subframe, all the CSI-RS AP may be included in a reference resource CSI n _{CQI _ ref} is defined to be. RS APs belonging to a plurality of CSI-RS APGs in different CSI-RS subframes are transmitted, and if another CSI-RS APG has different periods and / or offsets, each CSI-RS APG _{CQI ref _} n is greater than or equal to 4 or 5 for can be defined as the minimum value corresponding to each CSI-RS valid DL subframe in which APG is transmitted. (Hereinafter referred to as a 'vCSI reference resource') for measuring vCSI and a CSI reference resource (hereinafter referred to as 'hCSI reference resource') for measuring hCSI in a case where the UE divides CSI into vCSI and hCSI, n _{CQI _ ref} may be defined according to the corresponding CSI-RS CSI-RS subframe in which CSI-RS is transmitted by AP. That is, n _{CQI _ ref} is 4 or greater than 5, or equal to, defined as the minimum value corresponding to a CSI-RS subframe to which the CSI-RS transmission of CSI-RS AP is used to measure the vCSI for vCSI reference resource . And, hCSI n _{CQI _ ref} is 4 or greater than 5, or equal to, defined as the minimum value corresponding to a CSI-RS subframe to which the CSI-RS transmission of CSI-RS AP is used to measure the hCSI for reference resource .

Meanwhile, the CSI reporting method may include the following three methods (method M320, method M321, method M322) according to the periodicity or instantaneousness. The method M320 is a method in which the UE performs periodic CSI reporting. The method M321 is a method in which the UE performs aperiodic CSI reporting. Method M322 is a method in which a UE performs CSI reporting by correlating periodic CSI reporting and aperiodic CSI reporting.

In method M320, the UE transmits a periodic CSI report based on PUCCH to the BS. When the UE does not receive the UL grant, it transmits the CSI report through the PUCCH and transmits the CSI report through the PUSCH when the UL grant is received. In order to vary the reporting period for each CSI item, the base station sets parameters related to the period to the UE. On the other hand, for CSI reporting separated by vCSI and hCSI, the cycle for each CSI item is set, and the CSI reporting type can be newly defined.

In method M321, the UE transmits an aperiodic CSI report based on PUSCH to the BS. The terminal receives the CSI request from the base station via the CSI request field in the UL DCI format and thus performs the measurement and reporting. The base station may request the CSI report for some of the antenna ports of the antenna port using the CSI request field. As described above, when the base station sets up the CSI-RS using the CSI-RS accession, the CSI-RS APG ID of the corresponding CSI-RS APG or the plurality of CSI- A CSI-RS APG set ID (previously set via higher-layer signaling) designating RS APG may be included in the CSI request. Or a base station sets a CSI-RS using a multiple CSI process, a CSI process ID of a CSI process corresponding to the corresponding CSI-RS APG or a CSI process set ID corresponding to a plurality of CSI- layer signaling) may be included in the CSI request. Meanwhile, the BS may request the CSI for the desired spatial domain using the CSI request field. In this case, the BS may have to transmit the CSI-RS so that the UE can measure the CSI for the corresponding spatial domain.

Method M322 is a combination of Method M320 and Method M321. The BS may set the MS to periodically report the CSI, and in conjunction therewith, allow the MS to report the CSI non-periodically. The base station can inform the UE of the setting information about the interconnection of the periodic CSI report and the aperiodic CSI report through the high-layer signaling. The method M322 will be described with reference to Fig. FIG. 2 illustrates a cyclic CSI report and an aperiodic CSI report having P subframes at regular intervals.

As illustrated in FIG. 2, the UE, which is configured through the higher-layer signaling that periodic CSI reporting and aperiodic CSI reporting are linked to each other, performs CSI measurement for periodic CSI reporting as a criterion , And CSI measurements for aperiodic CSI reporting. Alternatively, the terminal may perform CSI measurements for periodic CSI reporting, based on (or as a basis for) CSI measurements for aperiodic CSI reporting. When the UE performs the aperiodic CSI report in the (n + 2P + c) th subframe, the CSI is measured based on the CSI reported in the (n + 2P + c) CSI to the base station periodically from the (n + 3P) th subframe. Where the criterion (or condition) may only be valid up to the next aperiodic CSI report. Alternatively, when the UE periodically reports the CSI to the (n + 2P) th subframe, the CSI is measured based on the periodically reported CSI, and the measured CSI is divided into (n + 2P + c) Lt; th > subframe. For example, the BS may set the MS to report the vCSI non-periodically and the MS may periodically report the measured hCSI based on the vCSI.

On the other hand, the CSI reporting method may include the following two methods (methods M320 and M321) according to the set number of CSI processes. Method M320 is a method by which a terminal performs reporting by setting up a single CSI process. Method M321 is a method for performing reporting by setting multiple CSI processes.

Both methods M320 and M321 are supported in the current specification. Methods M320 and M321, respectively, may be considered differently depending on the PUCCH-based cyclic CSI report or the PUSCH-based aperiodic CSI report.

In case that the UE performs periodic CSI reporting based on the PUCCH based on a single CSI process configuration, in order for the UE to divide vCSI and hCSI, a new reporting period related parameter should be defined according to the increased CSI items, The CSI reporting type shall be newly defined according to the transmission combination of the new CSI items.

If the terminal performs PUSCH based aperiodic CSI reporting based on a single CSI process configuration, the terminal may simultaneously transmit the CSI measured by method M300 or method M301.

In the case where the UE performs periodic CSI reporting based on the PUCCH based on setting of multiple CSI processes, a method in which the UE reports vCSI and hCSI in a divided manner is that the UE measures and reports vCSI and hCSI, respectively, , The way in which the CSI process is set up for each vCSI and hCSI. In such a case, the UE may reuse the PUCCH-based periodic CSI reporting scheme defined in the current standard as a reporting scheme for each CSI, or set the reporting period of vCSI and the reporting period of hCSI differentially A method of mitigating overhead may also be used. However, as described above, defining the reference CSI process so that the association information of two CSI processes is included in the CSI process setting or the CSI-RS setting, or the CSI of one CSI process becomes a reference for the CSI measurement of another CSI process . For example, when the base station allows the UE to measure hCSI based on vCSI, it can define a vCSI-reference CSI process and notify the terminal of the corresponding CSI process ID through high-layer signaling. The terminal can measure hCSI through a CSI process corresponding to hCSI, based on the vCSI measured (and / or reported) through the vCSI-reference CSI process. Thus, if the base station defines a vCSI-reference CSI process, it may be necessary to define the assumption of the terminal with the setting of the measured subframe set. Here, a measurement subframe set refers to a set of one or a plurality of subframe (s) capable of assuming the same channel and / or interference in the CSI measurement by the UE. A UE that has set up a measurement subframe set through higher-layer signaling can measure CSI for each measurement subframe set.

If the vCSI-reference CSI process is defined only for a single measurement subframe set, then the vCSI-reference CSI process is a reference for all of the plurality of measurement subframe sets in the hCSI measurement for a plurality of measurement subframe sets , The terminal can assume. That is, in the case where the vCSI-reference CSI process is set only for a single measurement subframe set, and a CSI process corresponding to hCSI is set for a plurality of measurement subframe sets, the terminal generates a corresponding vCSI-reference CSI The hCSI for all measurement subframe sets can be measured based on the vCSI of the process.

If the vCSI-reference CSI process is defined for each measurement subframe set, the terminal can assume that the vCSI-reference CSI process is only a reference for hCSI measurement of the corresponding measurement subframe set. That is, when a vCSI-reference CSI process is set for a plurality of measurement sub-frame sets and a CSI process corresponding to hCSI is set for the same measurement sub-frame sets, The hCSI for the corresponding measurement subframe set can be measured based on the vCSI for the frame set.

4. Codebook configuration and setting method

In order for a base station to transmit signals to a mobile station in order to form beams or perform precoding on the signals, a base station may use a channel vector (or a channel matrix, hereinafter referred to as a "channel matrix" It is necessary to acquire inferable channel state information. To this end, if the base station transmits a reference signal (e.g., NZP CSI-RS) to the UE, the UE estimates the channel using the reference signal.

In order to report the channel matrix estimated by the UE or the corresponding precoding matrix itself to the base station, an infinite feedback size is required. In order for the UE to report a channel matrix or a corresponding precoding matrix with a limited feedback size, a codebook consisting of a finite number of channel matrices or precoding matrices is defined. Each channel matrix or precoding matrix included in the codebook has its own Indicator (or Index). The base station and the terminal know the same codebook in advance. The terminal estimates a channel matrix having the best performance (or a selection index) when beamforming (or precoding) is performed using the channel matrix (or precoding matrix) included in the codebook, (Or a PMI) corresponding to the precoding matrix (or the precoding matrix) and reports it to the base station.

The base station forms a beam or performs precoding using a channel matrix (or a precoding matrix) corresponding to the reported PMI. On the other hand, if the number of transmit antenna ports is large, a larger number of feedback sizes may be required to follow the corresponding channel capacity increase.

On the other hand, in order to reduce the PMI feedback size, the codebook can be configured as a dual structure. In order for the UE to report one channel matrix (or precoding matrix) belonging to the codebook, the PMI can be divided into a first PMI and a second PMI. The first PMI may be defined to have a longer period or less frequent reporting than the second PMI. The first PMI may refer to a set of a plurality of channel matrices (or precoding matrices). The second PMI may include information for selecting one or more channel matrices (or precoding matrices) in a set of a plurality of channel matrices (or precoding matrices) pointed to by the first PMI, and / or May be defined to include information for combining all or a plurality of selected channel matrices (or precoding matrices).

Also, where the transmit antenna array is comprised of orthogonal pairs of antennas with dual polarization (i.e., when a cross polarization antenna is used), the second PMI may be defined to include information for co-phasing different polarizations . The plurality of channel matrices (or precoding matrices) referred to by the first PMI may be configured such that the beams corresponding to the respective columns of the matrix are adjacent to each other, or are spaced apart from each other by a predetermined distance. The former is suitable for use in systems with well-calibrated antennas and the latter can be used in systems where the antenna calibration is poor.

Therefore, in order to increase the performance, depending on the degree of antenna calibration of the base station, the plurality of channel matrices referred to by the first PMI may be configured differently. To this end, a codebook having a dual structure (hereinafter referred to as a 'dual codebook') is defined to have a plurality of first PMI configurations, and the BS transmits configuration information (or an indicator for indicating configuration information) signaling (or system information block (SIB) signaling, RRC signaling). The UE performs PMI selection and reporting based on the configuration information of the first PMI that has been set. Hereinafter, the configuration of the first PMI is referred to as a first PMI configuration. Defining the codebook so as to have a plurality of first PMI configurations is not limited to the purpose of being adaptive to the antenna calibration performance but can also be used for other purposes. As an example of a method for setting the configuration of the first PMI adaptively to the antenna calibration performance, the first PMI configuration of the dual codebook includes the configuration of four beams that are different from each other by 90 degrees. A base station satisfying a predetermined level of antenna calibration sets a first PMI configuration composed of four beams adjacent to the terminal and a base station whose antenna calibration does not satisfy a certain level is set to four A first PMI configuration consisting of beams can be established.

On the other hand, in order to mitigate interference due to the use of a particular PMI or to constrain a particular rank selection, a subset of codebooks may be constrained. Where the subset constraint of the codebook is such that constraints are imposed on some of the channel matrices (or precoding matrices) contained in the codebook such that the terminal does not select the portion and / or report on the portion it means. For example, if the codebook size is 16 (e.g., assuming that the indicator range in the codebook is between 0 and 15) and the codebook subset is not constrained, the terminal may select and report PMIs from 0 to 15. [ For another example, if the codebook subset is constrained so that indicators of 0 to 7 are not selected, the terminal may select and report PMIs at 8-15. In the existing codebook subset limiting method, the base station defines whether each indicator in the codebook is limited or not, as a bitmap (for example, defining bit 1 as a constraint and bit 1 as a constraint, Bit 0 is defined as allowable), and it is set to the UE through higher-layer signaling. Also, even if the codebook subset is constrained, the terminal can report the PMI with the same feedback size.

On the other hand, in order to quickly signal a codebook subset constraint, physical layer signaling such as DCI can be used. Since signaling resources are limited in the physical layer signaling, it may be impossible or ineffective to signal the selection constraint of each indicator in the codebook through the bitmap. In addition, even in a method of setting a codebook subset limitation using higher-layer signaling (or SIB signaling, RRC signaling), it is necessary to reduce the signaling overhead for codebook subset limitation of a large codebook.

As a method for solving this problem, there is a method of grouping a plurality of indicators (or PMIs) into groups and constructing a bit map based on whether or not to restrict the selection on a group basis (hereinafter referred to as 'first signaling overhead mitigation method'). For example, if the codebook size is 16, if the indicator of 0 to 3 is group 0, the indicator of 4 to 7 is of group 1, the indicator of 8 to 11 is of group 2, and the indicator of 12 to 15 is Group 3, the codebook subset constraint consists of a 4-bit bitmap. For example, if the base station configures the codebook subset constraint information of '0110' (eg, defining bit 0 as a constraint and allowing bit 1 as a constraint), then the terminal shall inform the group 0 and group 3 indicators It is interpreted that selection is restricted.

As another method for mitigating the signaling size for the codebook subset constraint, there is a method of using the structure of the double codebook (hereinafter referred to as a second signaling overhead mitigation method). A bitmap for a codebook subset constraint may be constructed in units of a first PMI. The selection of all channel matrices (or precoding matrices) referred to by the constrained first PMI (or the corresponding pair of first PMI and second PMI) may be constrained. For example, in the case where the size of the double codebook is 8 bits, the first PMI is composed of 4 bits, and the second PMI is composed of 4 bits, the bitmap size is composed of 256 bits in the existing codebook subset limiting method, When the codebook subset constraint is performed in units of PMI, the bitmap size is composed of 16 bits.

As another method for mitigating the signaling size for the codebook subset constraint, there is a method (hereinafter referred to as a third signaling overhead mitigation method) in which the first PMIs are constrained by grouping the first PMIs for the dual codebook. The third signaling overhead mitigation method is a combination of the above-described first and second signaling overhead mitigation methods. In such a case, the selection of all channel matrices (or precoding matrices) referred to by all the first PMIs belonging to the constrained group (or a pair of the first PMI and the second PMI corresponding thereto) is restricted.

As a method of expressing a codebook subset constraint, there may be a method of expressing a group indicator for grouping and constraining a plurality of indicators in addition to a method of expressing a codebook subset constraint by a bitmap. All indicators belonging to the named group indicator are constrained in selection.

In the codebook subset constraint based on the bitmap representation described above, the bitmap may contain all of the constraints for each rank, or the bitmap may be constructed in common for all ranks. In order for the latter case to be used, the first PMI may have to be defined identically for all ranks.

On the other hand, the constraint in all codebook subset limiting methods described above may be replaced with permissible. In this case, everything is the same as described above except that the meaning of the constraint is interpreted as permission.

Meanwhile, according to the conventional method, even if the codebook subset is restricted, the UE can report the PMI to the base station with the same feedback size. In order to reduce the feedback size, the UE can sequentially assign a new indicator to the remaining indicators except for the constrained indicator, and perform PMI reporting on the new indicator. Specifically, the terminal can reindegrate from 0 to the number of unconstrained indicators - 1 'in the order of the original indicators for the remaining indicators, with the exception of the constrained indicators. For example, if the indicator of 0, 1, 5, 10, 12, 13, 14, 15 is constrained in a codebook with an indicator of 0 to 15, New indicators are added.

Codebook indicator changes according to codebook constraints Original indicator 2 3 4 6 7 8 9 11 New indicator based on codebook constraints 0 One 2 3 4 5 6 7

The terminal reports to the base station a newly added indicator for the remaining indicators except for the constrained indicator. At this time, the size of the PMI has 3 bits, which is the size of the constrained codebook, not 4 bits. Since the BS is the host that sets the codebook subset limitation, it knows that the PMI is reported in 3 bits according to the codebook subset limitation, and based on the reported PMI, the unconstrained indicator can be interpreted as shown in Table 1 above. For example, when the terminal reports PMI 3 to the base station, the base station converts the reported PMI 3 to the original indicator 6 and obtains the channel matrix (or precoding matrix) corresponding to indicator 6.

5. How to set up the CSI process

In accordance with the TXRU virtualization and antenna port virtualization described above, the beam shape of the signal transmitted through the antenna port may be different. The beam shape can be characterized by the width of the beam and the direction of the beam. Therefore, in the CSI-RS AP transmission, the width and direction of the CSI-RS AP beam may be different due to the above two virtualization. Hereinafter, a first CSI-RS mode is defined in which a signal of a CSI-RS AP is transmitted so that a beam width is as wide as a cell coverage and different CSI-RS APs have the same beam width and beam direction. The second CSI-RS mode is defined to transmit a signal of the CSI-RS AP such that the beam width is smaller than the cell coverage and the combinations of different CSI-RS AP and CSI-RS resources have different beam directions.

Unlike in the first CSI-RS mode in the second CSI-RS mode, the UE selects all or part of the beams applied to the CSI-RS APs during the CSI measurement, and performs CSI (e.g., CQI, PMI, RI , And reports the result. Accordingly, the first CSI-RS mode and the second CSI-RS mode may be classified into a beam shape of a CSI-RS AP signal, or a feature that selects one or more beams and reports information related thereto in CSI measurement and reporting Or the like.

The terms for the first CSI-RS mode and the second CSI-RS mode may be replaced by CSI reporting class A and CSI reporting class B, respectively. Hereinafter, unless otherwise stated, the terms first CSI-RS mode and second CSI-RS mode are used. The base station may operate in a first CSI-RS mode, a second CSI-RS mode, or a combination of the two. Also, the base station can operate different modes for each terminal.

5.1. The first CSI- RS mode

Conventionally, one CSI process is associated with one CSI-RS resource (or NZP CSI-RS resource) and one CSI-IM resource. The CSI reported by the UE corresponds to the CSI process established through higher-layer signaling. Existing NZP CSI-RS resources can constitute 1, 2, 4, or 8 CSI-RS APs.

On the other hand, in the first CSI-RS mode, it is required to support NZP CSI-RS having number of antenna ports exceeding 8, such as 12 or 16. A method for configuring an NZP CSI-RS with more than eight antenna ports may include configuring a plurality of NZP CSI-RS resources having a 3GPP LTE Release 12 definition or having a new definition. For example, an NZP CSI-RS with 12 antenna ports can be configured with a combination of NZP CSI-RS resources with 8 antenna ports and NZP CSI-RS resources with 4 antenna ports, Lt; RTI ID = 0.0 > NZP CSI-RS < / RTI > If all NZP CSI-RS resources are constrained to have the same number of antenna ports, the latter setting may be used.

In order to set up a plurality of NZP CSI-RS resources, one CSI process may be associated with a plurality of NZP CSI-RS resources and one CSI-IM resource unlike the prior art. Specifically, a base station refers to an ID list indicating a plurality of NZP CSI-RS resource configurations and a CSI-IM resource configuration such that a plurality of NZP CSI-RS resource configurations and CSI-IM resource configurations are included in one CSI process configuration ID (CSI-IM resource configuration ID) in the CSI process configuration. That is, the base station inserts the NZP CSI-RS resource configuration ID list into the CSI process configuration instead of the existing NZP CSI-RS resource configuration ID. The NZP CSI-RS resource configuration ID list includes single or multiple NZP CSI-RS resource configuration IDs. The UE having received the CSI process configuration through higher-layer signaling measures the channel using the CSI-RS of the CSI-RS APs included in the NZP CSI-RS resources corresponding to the NZP CSI-RS resource configuration ID list, Measures the interference from the resources defined for the CSI-RS APs included in the CSI-IM resource corresponding to the CSI-IM resource configuration ID, measures the CSI from this, and reports the measured CSI to the base station. To this end, the terminal may assign the port number to the following two methods (method M410, method M420) for CSI-RS APs defined in a plurality of NZP CSI-RS resources.

The method M410 is a method of assigning a CSI-RS AP number in the order in which the terminal is inputted into the NZP CSI-RS resource configuration ID list (hereinafter referred to as 'first list'). For example, if the ID values in the NZP CSI-RS resource configuration ID list indicating two NZP CSI-RS resource configurations are set to 1, 0, and the first NZP CSI-RS resource configuration ID 1, the NZP CSI-RS resource corresponding to the next NZP CSI-RS resource configuration ID 0 has four ports, the UE transmits NZP CSI-RS A port number of 15 to 22 is assigned to 8 ports corresponding to the resource configuration ID 1 and a port number of 23 to 26 is assigned to the 4 ports corresponding to the NZP CSI-RS resource configuration ID 0, And the port number of the terminal.

The method M420 is a method in which the UE assigns the CSI-RS AP number in ascending (or descending) order of the NZP CSI-RS resource configuration ID of the first list. For example, if it is assumed that a UE assigns a CSI-RS AP number in ascending order of an NZP CSI-RS resource configuration ID, the ID values in the NZP CSI-RS resource configuration ID list indicating two NZP CSI- 1, and 0, the NZP CSI-RS resource corresponding to the NZP CSI-RS resource configuration ID 0 has 4 ports, and the NZP CSI-RS resource corresponding to the NZP CSI-RS resource configuration ID 1 has 8 Port, the terminal assigns a port number of 15 to 18 to the four ports corresponding to the NZP CSI-RS resource configuration ID 0, and the eight ports corresponding to the NZP CSI-RS resource configuration ID 1 The port number of 19 to 26 is assigned to the port number after the previous port number assignment.

5.2. The second CSI- RS mode

On the other hand, in the second CSI-RS mode, beams can be formed in different directions for NZP CSI-RS AP, NZP CSI-RS resources, or a combination thereof. Hereinafter, a resource unit including one or a plurality of NZP CSI-RS AP (s) to which the same beam is applied is referred to as a BF CSI-RS resource.

5.2.1. The second CSI- RS Mode  CSI- RS  How to set up

In a CSI-RS setting method for a second CSI-RS mode, in order to perform CSI measurement on a single beam or a plurality of beams, a terminal performs higher-layer signaling on a single or plural NZP CSI- I get set up. In this case, it can be assumed that beamforming is applied to the CSI-RS of all the CSI-RS APs in the same NZP CSI-RS resource in the same direction. In addition, the UE may assume that different beamforming is applied between CSI-RSs transmitted in different NZP CSI-RS resources. Therefore, one NZP CSI-RS resource corresponds to one BF CSI-RS resource. To this end, the base station may include a list of NZP CSI-RS resource configuration IDs in the CSI process configuration so that a plurality of NZP CSI-RS resource configurations are included in the CSI process configuration. Herein, the number of NZP CSI-RS APs belonging to different NZP CSI-RS resources can be set to the same. The different NZP CSI-RS resources set in one CSI process are different from each other in NZP CSI- It may not be expected to have an RS AP.

When the NZP CSI-RS resources have different numbers of NZP CSI-RS APs, the CSI reporting / feedback payload sizes differ depending on the selected beam (or NZP CSI-RS resource) at the time of CSI reporting, It may be difficult to assume this same CSI reporting / feedback payload size.

In addition, the UE receives a common CSI-IM resource for all the set NZP CSI-RS resources in a CSI process set through higher-layer signaling, or different CSI-CSI resources for each set NZP CSI- -IM resource can be set up. In the former case, one CSI process can be defined as one or more NZP CSI-RS resources and one CSI-IM resource, and the UE can measure the CSI by reflecting the same intra-cell interference . In the latter case, one CSI process may be defined as one or more NZP CSI-RS resources and one or more CSI-IM resources associated, and the terminal may determine NZP CSI-RS resources and CSI-IM resources CSI can be measured for each pair, reflecting different intra-cell interference and / or different inter-cell interference. If one CSI-IM resource is set in the CSI process, the UE follows the former, and if the CSI-IM resources corresponding to the number of NZP CSI-RS resources are set, the UE follows the latter.

It may not expect the UE to set a different number of CSI-IM resources than the number of NZP CSI-RS resources. In order to set a plurality of CSI-IM resources, a plurality of CSI-IM resource configuration ID lists may be included in the CSI process configuration. The NZP CSI-RS resource and the CSI-IM resource are paired with each other in the same order, and the UE uses the CSI-RS of the CSI-RS APs belonging to the NZP CSI-RS resource in the pair Measure the channel, measure the interference on the resources defined for the CSI-RS APs belonging to the CSI-IM resource, and obtain the CSI from these (the measured channel and the measured interference). The UE measures a channel for CSI-RS APs of NZP CSI-RS resources corresponding to each beam as described above, and measures a channel corresponding to a common CSI-IM resource (or corresponding beam (or corresponding NZP CSI-RS resource) CSI-IM resources) to select the single or multiple beam (s), measure the CSI for the selected beam (s), and report the CSI. Here, the terminal may represent the NZP CSI-RS resource configuration ID (s) corresponding to the selected beam (s), or a bitmap thereof, to be included in the CSI report. The former is advantageous when the terminal selects a single beam, and the latter can be advantageous when selecting a plurality of beams. The bitmap size can be defined as the maximum number of NZP CSI-RS resources that can be set (included) in one CSI process or the number of NZP CSI-RS resources set in one CSI process. The first bit from the left (or right) bitmap corresponds to the lowest (or higher) NZP CSI-RS resource configuration ID and the second bit corresponds to the second lowest (or higher) NZP CSI-RS resource configuration ID And the remaining bits may be defined to correspond to the ascending (or descending) order of the NZP CSI-RS resource configuration ID. A bit having a value of 0 in the bitmap means that the NZP CSI-RS resource (or a corresponding beam) is not selected and a bit having a value of 1 means that the NZP CSI-RS resource May be defined to mean selected, and may be defined to have the opposite meaning.

If the large-scale property of a channel on which a symbol of an antenna port of a channel is transmitted can be deduced from a channel of a symbol to which another antenna port is transmitted, the two antenna ports are defined as quasi co-located. Here, the large-scale channel attribute may include one or a combination of one or more of Doppler shift, Doppler spread, average delay, delay spread, and average gain.

In a UE with a transmission mode of 8 to 10 for a serving cell, the DM-RS APs 7 to 14 of the serving cell in a given subframe are subjected to a QCL (quasi co-quadrature polynomial) for Doppler shift, Doppler spread, average delay, -location). The UE can assume a QCL for delay spread, Doppler spread, Doppler shift, average gain, and average delay between CSI-RS APs belonging to a CSI-RS resource configuration.

The UEs having the transmission modes 1 to 9 set for the serving cell are subjected to Doppler shift, Doppler spread, and average delay in the CRS APs 0 to 3, the DM-RS AP 5, the DM-RS APs 7 to 14, and the CSI- , And the delay spread can be assumed to satisfy the QCL.

The UE having the transmission mode 10 set for the serving cell decodes the PDSCH for demodulating using the DM-RS by using the following two types of QCLs (QCL Type A and QCL Type B) by the higher-layer parameter qcl-Operation define.

First, for the QCL Type A, the terminal transmits a QCL for Doppler shift, Doppler spread, average delay, and delay spread between CRS APs 0 to 3, DM-RS APs 7 to 14, and CSI- Can be assumed. The CSI-RS APs 15 to 22 may be replaced with CSI-RS APs 15 to (K + 14) to support the number of extended antenna ports for the first CSI-RS mode. Where K is the maximum configurable number of CSI-RS APs for one CSI process.

Then, for QCL Type B, the UE transmits CSI-RS APs 15 to 22 corresponding to the CSI-RS resource configuration identified by the higher-layer parameter qcl-CSI-RS-ConfigNZPId-r11 and the corresponding qcl- Between the DM-RS APs 7 to 14 in the resource to which the PDSCH scheduled (or allocated) by the DL DCI format including the 'PDSCH RE Mapping and Quasi-Co-Location Indicator' field corresponding to -RS-ConfigNZPId- The QCL for Doppler shift, Doppler spread, average delay, and delay spread can be assumed. The CSI-RS APs 15 to 22 may be replaced with CSI-RS APs 15 to (K + 14) to support the number of extended antenna ports for the first CSI-RS mode. Where K is the maximum configurable number of CSI-RS APs for one CSI process.

The UE having the transmission mode 10 and the QCL Type B set between the CRS APs 0 to 3 corresponding to the qcl-CRS-Info-r11 of the CSI-RS resource configuration and the CSI-RS APs 15 to 22 of the CSI- The QCL for Doppler shift and Doppler spread can be assumed. The CSI-RS APs 15 to 22 may be replaced with CSI-RS APs 15 to (K + 14) to support the number of extended antenna ports for the first CSI-RS mode. Where K is the maximum configurable number of CSI-RS APs for one CSI process.

As described above, when the BF CSI-RS resources are classified according to the NZP CSI-RS resources in the second CSI-RS mode, the UE allocates all large-scale channels between the CSI-RS APs belonging to different NZP CSI- QCL for the attribute can not be assumed, only QCL for Doppler shift and Doppler spread can be assumed, only QCL for Doppler shift, Doppler spread, average delay, and delay spread can be assumed, or Doppler shift, Doppler spread , QCL for average delay, delay spread, and average gain can be assumed. One QCL hypothesis that the terminal can follow among these four QCL hypotheses can be defined in advance. Alternatively, the base station may set a QCL hypothesis for a large-scale channel property between the CSI-RS APs belonging to different NZP CSI-RS resources (for example, one of the above four assumptions can be set) through higher- And the UE can follow the established assumption through higher-layer signaling.

A terminal with Transmission mode 10 set to Transmission mode 1 to 9 or QCL Type A can transmit QCLs between DM-RS antenna ports (except DM-RS AP 5 in Transmission mode 10) and CSI- You may need to make changes to your home. The terminal shall transmit the NZP CSI-RS resource indicator (s) corresponding to the most recently reported (or most recently reported before k3 subframe before the current subframe) 'selected beam (s) RSAP antenna ports of the NZP CSI-RS resource (s) referred to by the NZP CSI-RS resource configuration ID (s) (or NZP CSI-RS resource configuration ID Is satisfied. Here, k3 > = K3, and K3 may be set to a value greater than or equal to 0, taking into consideration the period between the reporting time of the information and the reception time of the DL allocation information using the information. The establishment of the hypothesis may be defined in advance, or the base station may establish the hypothesis through higher-layer signaling to the terminal, and the terminal may follow the hypothesis.

The terminal is configured with DM-RS antenna ports and an NZP CSI-RS resource indicator corresponding to the most recently reported (or most recently reported) k ' selected beam (s) Scale channel attributes between the CSI-RS antenna ports of the NZP CSI-RS resource (s) not referenced by the NZP CSI-RS resource (s) (or NZP CSI-RS resource configuration ID Or only QCL for Doppler shift and Doppler spread can be assumed, or only QCL for Doppler shift, Doppler spread, average delay, and delay spread can be assumed. Here, k3 > = K3, and K3 may be set to a value equal to or greater than 0 in consideration of the period between the reporting time of the information and the reception time of the DL allocation information using the information. One QCL hypothesis that the UE can follow in the QCL assumption of these three (or only three of the candidates) may be defined in advance, and the base station may transmit the three Or a QCL hypothesis with only a subset of the three candidates). In this case, the terminal can follow the set QCL assumption.

RSs 15 to 22 corresponding to the CSI-RS resource configuration identified by the higher-layer parameter qcl-CSI-RS-ConfigNZPId-r11 and the corresponding QCl-RS APs 15 to 22 corresponding to the CSI- RS APs 7 to 7 in the resource to which the PDSCH scheduled to be allocated (or allocated) by the DL DCI format including the 'PDSCH RE Mapping and Quasi-Co-Location Indicator' field corresponding to -CSI- 14 Doppler shift, Doppler spread, average delay, and delay spread. In this case, a method is needed to support the case where the maximum NZP CSI-RS resource configuration number that can be set exceeds the existing limit value of 3.

The first support method is to extend the PDSCH-RE-MappingQCL-ConfigId field size to the maximum number of NZP CSI-RS resource configurations that can be set.

The second support method maintains the PDSCH-RE-MappingQCL-ConfigId range (existing range is 1 to 4) with the PDSCH RE Mapping and Quasi-Co-Location Indicator field size (original size is 2 bits) The CSI process ID to which the NZP CSI-RS resource corresponding to qcl-CSI-RS-ConfigNZPId-r11 belongs is included in place of qcl-CSI-RS-ConfigNZPId-r11 of the RE-MappingQCL-Config parameter.

In this case, the terminal is configured with the CSI-RS APs 15 to 22 corresponding to the CSI-RS resource configuration (s) identified by the CSI process ID instead of the higher-layer parameter qcl-CSI-RS-ConfigNZPId- (Or allocated) by a DL DCI format including a 'PDSCH RE Mapping and Quasi-Co-Location Indicator' field corresponding to the corresponding qcl-CSI-RS-ConfigNZPId-r11. QCL for all large-scale channel attributes between 7 and 14 can not be assumed, QCL for Doppler shift and Doppler spread can be assumed, or QCL for Doppler shift, Doppler spread, average delay, and delay spread can be assumed can do. One QCL assumption that can be followed by the UE among these three QCL assumptions may be defined in advance, and the base station may transmit the QCLs (or only three of them) to the UE through higher-layer signaling, You can also set one of the assumptions. In this case, the terminal can follow the set QCL assumption.

RSs 15-22 corresponding to the CSI-RS resource configuration (s) identified by the CSI process ID in place of the higher-layer parameter qcl-CSI-RS-ConfigNZPId-r11 and the corresponding qcl- (Or assigned) by the DL DCI format including the 'PDSCH RE Mapping and Quasi-Co-Location Indicator' field corresponding to the CSI process ID instead of CSI-RS-ConfigNZPId-r11. QCL for all large-scale channel attributes between RS APs 7-14 can not be assumed, QCL for Doppler shift and Doppler spread can be assumed, or QCL for Doppler shift, Doppler spread, average delay, and delay spread QCL can be assumed. One QCL assumption that can be followed by the UE among these three QCL assumptions may be defined in advance, and the base station may transmit the QCLs (or only three of them) to the UE through higher-layer signaling, You can also set one of the assumptions. In this case, the terminal can follow the set QCL assumption.

Alternatively, the UE may determine whether the most recently reported (or the most recent) sub-frame before the k3 sub-frame based on the current sub-frame, for the CSI process identified by the CSI process ID on behalf of the higher-layer parameter qcl-CSI-RS-ConfigNZPId- The CSI-RS resource (s) of the NZP CSI-RS resource (s) referred to by the NZP CSI-RS resource indicator (s) (or NZP CSI-RS resource configuration ID (s)) corresponding to the selected beam (Or assigned) PDSCH according to the DL DCI format including the CSI-RS APs 15 to 22 and the 'PDSCH RE Mapping and Quasi-Co-Location Indicator' field corresponding to the corresponding CSI process ID QCL for all large-scale channel attributes between DM-RS APs 7 ~ 14 in the transmitted resource can not be assumed, QCL for Doppler shift and Doppler spread can be assumed, or Doppler shift, Doppler spread, And the QCL for the delay spread. Here, k3 > = K3, and K3 may be set to a value equal to or greater than 0 in consideration of the period between the reporting time of the information and the reception time of the DL allocation information using the information. One QCL assumption that can be followed by the UE among these three QCL assumptions may be defined in advance, and the base station may transmit the QCLs (or only three of them) to the UE through higher-layer signaling, You can also set one of the assumptions. In this case, the terminal can follow the set QCL assumption.

Or the base station groups the NZP CSI resource (s) on which the QCL between the CSI-RS antenna ports belonging to one or more NZP CSI resource (s) can be assumed and assigns an ID (NZP CSI resource group ID or NZP CSI resource configuration group ID; the range may be 1 to 4), and notify the UE through higher-layer signaling. This method is a method of using the NZP CSI resource group ID instead of the CSI process ID in the method using the above-described CSI process ID.

Alternatively, the UE can acquire the CRS APs 0 to 3 corresponding to the qcl-CRS-Info-r11 parameter included in the CSI-RS resource configuration (s) identified by the higher-layer parameter qcl-CSI-RS- ConfigNZPId- (Or allocated) by a DL DCI format including a 'PDSCH RE Mapping and Quasi-Co-Location Indicator' field corresponding to the corresponding qcl-CSI-RS-ConfigNZPId-r11. QCL for all large-scale channel attributes between 7 and 14 can not be assumed, QCL for Doppler shift and Doppler spread can be assumed, or QCL for Doppler shift, Doppler spread, average delay, and delay spread can be assumed can do. One QCL hypothesis that can be followed by the UE among these three QCL assumptions may be defined in advance, and the base station may transmit the QCL assumption of three (or only three of the three candidates) through higher-layer signaling to the UE Can be set. In this case, the terminal can follow the set QCL assumption.

The UE may determine whether the CSI process set by the higher-layer signaling includes a plurality of NZP CSI-RS resources corresponding to each beam, a PMI for each NZP CSI-RS resource or at least one selected NZP CSI- And RI, or may obtain a common PMI and RI for all NZP CSI-RS resources or for at least one selected NZP CSI-RS resource. The UE can then obtain the CQI using the PMI (s) and RI (s) obtained for all NZP CSI-RS resource (s) or selected NZP CSI-RS resource (s). Here, PMI and CQI are values based on wideband or subband. The UE reports the obtained CQI, PMI, and RI to the base station.

5.2.2. The second CSI- RS Mode  CSI- RS  Other ways of setting up

Another method of establishing CSI-RS for the second CSI-RS mode is to allow a terminal to establish a single or multiple NZP CSI-RS resources in a CSI process through higher-layer signaling, where one NZP CSI- Is a method including a plurality of BF CSI-RS resources. That is, one NZP CSI-RS resource may include CSI-RS APs to which a plurality of different beams are applied. Here, the set of NZP CSI-RS AP (s) to which the same beam is applied is defined as NZP CSI-RS AP group. To this end, the CSI process configuration may include a plurality of NZP CSI-RS resource configuration ID lists. In addition, additional information is required to set a plurality of NZP CSI-RS AP groups in one NZP CSI-RS resource. The additional information includes NZP CSI-RS AP numbers in the NZP CSI-RS AP group or NZP CSI- And may include the number of RS AP groups. As described above, the number of NZP CSI-RS APs belonging to different BF CSI-RS resources (or NZP CSI-RS AP groups) in order to avoid ambiguity about the CSI reporting / Can be set the same. In addition, the total number of NZP CSI-RS APs of the NZP CSI-RS resource is a multiple of the number of NZP CSI-RS APs belonging to one BF CSI-RS resource (or the number of NZP CSI-RS APs of each NZP CSI- A multiple of the number of NZP CSI-RS APs belonging to the CSI-RS resource), or only configuration parameters satisfying these conditions can be defined. Different IDs are assigned to all NZP CSI-RS AP groups across all NZP CSI-RS resources established in a CSI process. In addition, the UE may receive one CSI-IM resource for all the NZP CSI-RS resources set in common in one CSI process set through higher-layer signaling, CSI-IM resources can be set up. In the former case, the UE can measure the CSI by reflecting the same intra-cell interference. In the latter case, the UE can measure CSI by reflecting different intra-cell interference and / or different inter-cell interference. If one CSI-IM resource is set in the CSI process, the UE follows the former, and if the CSI-IM resources corresponding to the number of NZP CSI-RS resources are set, the UE follows the latter. The UE may not expect to set a different number of CSI-IM resources than the number of NZP CSI-RS resources. In order to configure a plurality of CSI-IM resources, the CSI process configuration may include a plurality of CSI-IM resource configuration ID lists. The NZP CSI-RS resource and the CSI-IM resource are paired with each other in the same order in the list of their respective CSI-RS resources, and the UE transmits the CSI-RS resource included in each of the BF CSI- RS resources belonging to the NZP CSI- Measures the channel using the CSI-RS of the RS APs, measures the interference on the resource defined for the CSI-RS APs belonging to the CSI-IM resource, and obtains the CSI from the measured channel and interference.

As described above, when BF CSI-RS resources are classified for each CSI-RS AP group, the UE may need to change the QCL assumption between the antenna ports. In the past, the UE could assume a QCL for delay spread, Doppler spread, Doppler shift, average gain, and average delay between all CSI-RS APs included in the same CSI-RS resource configuration. However, If the CSI-RS APs in the configuration are transmitted from different beams, then the existing QCL assumption may not be desirable. Therefore, even if the CSI-RS APs belong to the same NZP CSI-RS resource, the UE can only estimate the delay spread, the Doppler spread, the Doppler shift, the average gain, and the average delay only between the CSI- QCL can be assumed.

In addition, when the PDSCH is transmitted in the transmission mode 10, the NZP CSI-RS AP group is configured using qcl-CSI-RS-ConfigNZPId-r11 in the 'PDSCH RE Mapping and Quasi-Co-Location Indicator' It is necessary to replace qcl-CSI-RS-ConfigNZPId-r11 with the NZP CSI-RS AP group ID corresponding to the beam to which the corresponding PDSCH is transmitted. If the number of beams (or the number of NZP CSI-RS AP groups) is larger than the previously settable qcl-CSI-RS-ConfigNZPId-r11 size, the size of the field can be increased. A maximum number of NZP CSI-RS AP groups is defined, and each CSI process establishes a lesser or equal number of NZP CSI-RS AP groups. Since the base station and the UE know the maximum number of NZP CSI-RS AP groups, it sets and assumes the PDSCH RE Mapping and Quasi-Co-Location Indicator field size accordingly. Transmission and reception.

If the CSI process set up through higher-layer signaling includes a plurality of NZP CSI-RS AP groups corresponding to each beam, the AT transmits the NZP CSI-RS AP group or each selected NZP CSI- PMI and RI can be obtained for each group or a common PMI and RI can be obtained for all NZP CSI-RS AP groups or for at least one selected NZP CSI-RS AP groups. The UE can obtain the CQI using the PMI (s) and RI (s) obtained for all NZP CSI-RS AP group (s) or selected NZP CSI-RS AP group (s). Here, PMI and CQI are values based on wideband or subband. The UE reports the obtained CQI, PMI, and RI to the base station.

On the other hand, a plurality of NZP CSI-RS resources can be set in one CSI process in the first CSI-RS mode and the second CSI-RS mode. It is difficult for the UE to distinguish between the first CSI-RS mode and the second CSI-RS mode only by receiving the CSI-RS AP according to the set NZP CSI-RS resource. On the other hand, in the first CSI-RS mode, the UE performs CSI measurement on the number of all CSI-RS APs set for a plurality of NZP CSI-RS resources, whereas in the second CSI- Measures CSI for -RS resources or for at least one selected NZP CSI-RS resource. Therefore, in order for the UE to perform CSI measurement and reporting in the CSI-RS mode intended by the BS, it is necessary to signal to the UE which CSI-RS mode (or CSI reporting class) CSI measurement and reporting is required in the CSI process . For this or other purposes, the CSI process configuration may include CSI-RS mode (or CSI reporting Class) configuration information. The base station includes CSI-RS mode (or CSI reporting class) configuration information in the CSI process configuration set for the UE through higher-layer signaling, and the UE having set the CSI-RS mode (or CSI reporting class) Perform CSI measurement and reporting.

6. Measurement restriction  Way

During CSI measurement, the UE measures a channel experienced by a serving cell (or a base station) when a physical channel (or signal) that is a target thereof is transmitted, and measures interference caused by another cell (or a base station) and / Or a base station) from a physical channel (or signal) that does not target itself. Hereinafter, the former is referred to as channel measurement and the latter is referred to as interference measurement.

On the other hand, measurement restriction (MR) means that channel measurement or interference measurement is performed only within a limited interval (time domain and / or frequency domain). The base station operating the second CSI-RS mode may change the beam applied to the CSI-RS AP according to the change of the terminals sharing the CSI-RS resource or the channel change.

Referring to FIGS. 3A and 3B, a method of MR application in the time domain will be described. Specifically, FIG. 3A shows a case where explicit measurement reset is not set, and FIG. 3B shows a case where an explicit measurement reset is set.

As illustrated in FIG. 3A, a UE measures channels used in CSI calculation in X NZP CSI-RS subframes (including CSI reference resources) up to CSI reference resources. The UE measures the interference used in the CSI calculation in Y CSI-IM subframes (including the CSI reference resource) up to the CSI reference resource when CSI-IM is set. If the CSI-IM is not set, Resources to V valid DL subframes (including CSI reference resources) or valid special subframes (including CSI reference resources).

The application of MR can be set by higher-layer signaling, and the MR for channel measurement and the MR for interference measurement can be set independently of each other. The value of each of X, Y, and V may be defined as a fixed value (method M600), may be set through higher-layer signaling, or may be defined by a terminal within a certain range (method M601).

Referring to FIG. 3B, a method for the terminal to set the values of X, Y, and V within a certain range will be described. For example, a certain range for X may be 1 to Z _X , a certain range for Y to 1 to Z _Y , and a certain range for V to 1 to Z _V. Here, Z _X , Z _Y , and Z _V are the intervals between the most recently measured subframe and the CSI reference resource (specifically, the subframe to which the CSI reference resource belongs since the most recently measured subframe) Lt; RTI ID = 0.0 > CSI-RS < / RTI > The period and the offset can be set by higher-layer signaling so that the sub-frame (measurement reset sub-frame) for which the measurement is reset is constantly repeated. For example, if the last measured subframe is the 5th subframe of the 10th frame, the CSI reference resource is the 5th subframe of the 15th frame, and the NZP CSI-RS subframe When the cycle of the CSI-IM sub-frame (MR time for interference measurement) is 5 subframes, Z _X or Z _Y May be 10, and the terminal selects one of the numbers from 1 to 10 as the value of X or Y (W in FIG. 3B represents the selected value) and applies it to the MR for channel measurement or interference measurement .

In the event that the periodic measurement reset described above is set (method M602), the base station notifies the change of the beam (s) applied to the CSI-RS AP (s) belonging to the CSI- Can be performed in the most recent NZP CSI-RS subframe (at the time of MR for channel measurement). Alternatively, in the case where the above-mentioned periodic measurement reset is set, the base station transmits the change of the beam (s) applied to the CSI-RS AP (s) belonging to the CSI-RS resource to the CSI- MR). ≪ / RTI > The UE may not expect that the period of the measurement reset (hereinafter referred to as 'first measurement reset') for PUCCH-based periodic CSI reporting is set to be smaller than the beam selection reporting period. The integer multiple value may also be included in the corresponding higher-layer signaling as the period setting parameter of the first measurement reset, such that the period of the first measurement reset is an integer multiple of the beam selection reporting period. Alternatively, the period of the first measurement reset may not be explicitly set, but may be defined to be equal to the beam selection reporting period, or an integer multiple (a predetermined integer multiple) of the beam selection reporting period. Alternatively, the sub-frame of the first measurement reset may be defined as a beam selection reporting sub-frame.

From the system point of view, the BF CSI-RS resource (which may be defined as the NZP CSI-RS resource or the NZP CSI-RS AP group in the above-mentioned '5. CSI process setup method') can be shared by a plurality of terminals And the UE can set a plurality of BF CSI-RS resources. For this case, when the base station sets the X, Y, V, and B signals by BF CSI-RS resource (or CSI-RS AP group corresponding to one beam) at the time of MR setting by higher- And / or information about the measurement reset setting (period and / or offset of the measurement reset subframe) may be included in the MR setting or the CSI process configuration. For example, a first BF CSI-RS resource is set up by a first terminal, a first BF CSI-RS resource among BF CSI-RS resources is shared by a first terminal and a second terminal, a second BF CSI- If the -RS resource is shared by the first terminal and the third terminal, X for the first BF CSI-RS resource may be set to 2, and X for the second BF CSI-RS resource may be set to 4.

Embodiments using MR may include the following. '5. The method M600 in which the MR is not applied to the channel measurement of the first CSI-RS mode and the Y = 1 is measured for the interference measurement may be applied. For channel measurements in the second CSI-RS mode, method M600 or method M602 with Y = 1 can be applied and method M600 with Y = 1 for interference measurement can be applied.

In establishing a plurality of CSI processes, when aperiodic CSI reporting for a plurality of CSI processes is set to be simultaneously requested by the base station and MRs are all set for the corresponding CSI processes, The CSI-RS for periodic CSI reporting may not be expected to be configured through the same CSI-RS resource configuration.

7. The base station and the terminal

4 shows a base station 100 transmitting a CSI-RS according to an embodiment of the present invention.

The base station 100 illustrated in FIG. 4 includes a radio frequency (RF) converter 130, a processor 110, a memory 120, and an antenna module 140.

The processor 110 may be configured to implement the functions, procedures, and methods described herein in connection with a base station. In addition, the processor 110 can control each configuration of the base station 100.

The memory 120 is coupled to the processor 110 and stores various information related to the operation of the processor 110. [

RF converter 130 is coupled to processor 110 and transmits or receives radio signals. The RF converter 130 includes a transmitting module 131 and a receiving module 132.

The base station 100 receives the CSI report from the terminal through the receiving module 132. [

The base station 100 stores in the memory 120 information necessary for CSI-RS setting, information required for CSI measurement & report setting, and / or set information. Also, the base station 100 stores the CSI reported from the terminal in the memory 120.

The base station 100 performs CSI-RS setting and CSI measurement & report setting through the processor 110 according to the methods described herein.

The base station 100 transmits the CSI-RS setting information, the CSI measurement & report setting information, and the CSI-RS according to the CSI-RS setting information to the transmitting module 130.

5 shows a terminal 200 measuring and reporting CSI according to an embodiment of the present invention.

The terminal 200 illustrated in FIG. 5 includes an RF converter 230, a processor 210, a memory 220, and an antenna module 240.

The processor 210 may be configured to implement the functions, procedures, and methods described herein in connection with a terminal. In addition, the processor 210 can control each configuration of the terminal 200. [

The memory 220 is coupled to the processor 210 and stores various information related to the operation of the processor 210. [

The RF converter 230 is connected to the processor 210 and transmits or receives a radio signal. The RF converter 230 includes a transmitting module 231 and a receiving module 232.

The terminal 200 receives the CSI-RS setting information, the CSI measurement & report setting information, and the CSI-RS accordingly from the base station 100 via the receiving module 232. [

The terminal 200 stores the received CSI-RS setting information and CSI measurement & report setting information in the memory 220.

The terminal 200 measures the CSI from the CSI-RS according to the methods described herein, through the processor 210. [ The terminal 200 stores the measured CSI in the memory 220.

The terminal 200 performs, via the processor 210, a report on the CSI stored in the memory 220, according to the methods described herein.

The terminal 200 transmits the CSI to be reported to the base station 100 through the transmission module 231. [

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

Claims (20)

A method for transmitting a channel state information (CSI) -reference signal (RS) in a multiple input multiple output (MIMO) antenna system,
Periodically transmitting a CSI-RS for a first CSI to a terminal;
Requesting the terminal to transmit a second CSI in a first subframe; And
Frame from the first sub-frame to the second sub-frame, which is a sub-frame after the first offset set for the CSI-RS transmission from the first sub-frame, when the CSI-RS occasion is set, RS to the MS during the duration of the RS CSI
And transmitting the CSI-RS to the base station. The method according to claim 1,
Wherein the first CSI is a CSI for one of a horizontal domain and a vertical domain, the second CSI is a CSI for the remaining domain,
The step of requesting the terminal to transmit the second CSI comprises:
Requesting transmission of the second CSI to the terminal if it determines that at least one of update to the second CSI and feedback to the second CSI is needed
A CSI-RS transmission method of a base station. The method according to claim 1,
The step of requesting transmission of the CSI-RS for the second CSI comprises:
Receiving a transmission request of the CSI-RS for the second CSI from the terminal in a third sub-frame; And
Requesting transmission of the second CSI from the third sub-frame to the terminal in the first sub-frame that is a sub-frame after a second offset set for CSI-RS transmission from the third sub-frame
A CSI-RS transmission method of a base station. The method of claim 3,
The receiving of the CSI-RS transmission request for the second CSI comprises:
Receiving a transmission request of the CSI-RS for the second CSI from the terminal through at least one of a physical uplink control channel (PUCCH) and a medium access control (CE) control element (CE)
A CSI-RS transmission method of a base station. The method of claim 3,
The transmission request of the CSI-RS for the second CSI,
When the degree of change of a value or value for at least one of a reference signal received power (RSRP), a received signal strength indicator (RSSI), a reference signal received quality (RSRQ), and a channel quality indicator (CQI) Transmitted by the terminal
A CSI-RS transmission method of a base station. The method according to claim 1,
The step of transmitting the CSI-RS for the second CSI comprises:
In the subframe in which the CSI-RS for the first CSI is transmitted, the CSI-RS for the second CSI is not transmitted or the CSI-RS for the second CSI is not overlapped with the CSI- Establishing a CSI-RS transmission resource
A CSI-RS transmission method of a base station. The method according to claim 1,
Further comprising the step of setting interlinkage information between the periodic CSI report of the MS and the aperiodic CSI report of the MS to the MS through signaling between the BS and the MS,
CSI measurement for non-periodic CSI reporting of the UE is performed based on CSI measurement for periodic CSI reporting of the UE by the UE having set up the interlinkage information
A method of establishing a base station. A method for a base station to measure and report channel state information (CSI) in a multiple input multiple output (MIMO) antenna system,
Grouping a plurality of CSI-RS antenna ports into a plurality of CSI-RS antenna port groups;
RS antenna port group to a subscriber station (DSI) when requesting a CSI report of a first CSI-RS antenna port group among the plurality of CSI-RS antenna port groups to the subscriber station, Into a CSI request field of a downlink control information (DCI) format; And
Requesting non-periodic CSI reporting to the terminal using the CSI request field of the DCI
The base station comprising: 9. The method of claim 8,
The method comprising: in the CSI request field of the DL DCI format, information corresponding to the at least one domain when requesting a CSI report for at least one of a horizontal domain and a vertical domain to the terminal;
Further comprising the steps of: 9. The method of claim 8,
When the terminal desires to measure a second domain CSI based on a first domain CSI of a first domain CSI and a second domain CSI, a first CSI process for the first domain CSI and a second domain CSI Setting the first CSI process as a reference CSI process among a second CSI process for the first CSI process; And
Further comprising the step of informing the terminal of the process identifier indicating the first CSI process as information of the reference CSI process,
Wherein the first domain CSI is one of a horizontal domain CSI and a vertical domain CSI and the second domain CSI is one of the horizontal domain CSI and the vertical domain CSI
A method of establishing a base station. 11. The method of claim 10,
Wherein setting the first CSI process as a reference CSI process comprises:
Setting the reference CSI process for a first set of CSI measurement subframes to the UE; And
And setting the second CSI process for a plurality of second CSI measurement subframe sets to the terminal,
Wherein the second domain CSI for the plurality of second CSI measurement subframe sets is measured by the terminal on the basis of the first domain CSI for the first set of measured subframes measured through the reference CSI process
A method of establishing a base station. 11. The method of claim 10,
Wherein setting the first CSI process as a reference CSI process comprises:
And setting the reference CSI process and the second CSI process for a plurality of CSI measurement subframe sets to the terminal,
Wherein the second domain CSI for each of the plurality of CSI measurement subframe sets is measured by the terminal on the basis of the first domain CSI for each of the plurality of CSI measurement subframe aggregates measured through the reference CSI process felled
A method of establishing a base station. A method for a base station to set up a process of channel state information (CSI) in a multiple input multiple output (MIMO) antenna system,
When operating in a first CSI-RS mode in which a plurality of CSI-RS (reference signal) antenna ports have the same beam width and beam direction, a plurality of first identifiers And a second identifier indicating one CSI-IM (interference measurement) resource configuration, into one first CSI process configuration information;
Setting the first CSI process configuration information to the terminal; And
Receiving, from the terminal, the measured CSI according to the first CSI process setting information
The base station comprising: 14. The method of claim 13,
Wherein a number of a plurality of CSI-RS antenna ports included in a plurality of CSI-RS resources corresponding to the plurality of first identifiers is included in the first CSI process setting information by the terminal Order or a value of the plurality of first identifiers
A method of establishing a base station. 14. The method of claim 13,
RS mode in which all or part of the plurality of CSI-RS antenna ports have different beam directions, a plurality of third identifiers indicating a plurality of CSI-RS resource configurations and a plurality of CSI- Including a plurality of fourth identifiers indicating an IM resource configuration in one second CSI process configuration information;
Setting the second CSI process configuration information to the terminal; And
Further comprising receiving from the terminal a measured CSI according to the second CSI process configuration information
A method of establishing a base station. 16. The method of claim 15,
Selecting one of the first CSI-RS mode and the second CSI-RS mode; And
Further comprising the step of including information indicating the selected mode in the setting information corresponding to the selected mode among the first CSI-RS process setting information and the second CSI-RS process setting information
A method of establishing a base station. 16. The method of claim 15,
RS mode, Doppler shift, Doppler spread, and Doppler spread between the first CSI-RS antenna port and the DM (demodulation) -RS antenna port of the plurality of CSI-RS antenna ports, the UE assumes that a quasi co-location (QCL) for a spread, an average delay, and a delay spread is satisfied,
The first CSI-RS antenna port is a CSI-RS antenna port belonging to a CSI-RS resource indicated by a first identifier selected by the terminal among the plurality of third identifiers
A method of establishing a base station. 16. The method of claim 15,
RS mode, a Doppler shift, a Doppler spread, an average delay, and a delay spread between a first CSI-RS antenna port and a first DM-RS antenna port of the plurality of CSI- The UE assumes that QCLs for up to four QCLs are satisfied,
The first CSI-RS antenna port may be configured to transmit, to a CSI process corresponding to QCL information set by physical layer signaling from the base station for PDSCH (physical downlink shared channel) reception, A CSI-RS antenna port belonging to a CSI-RS resource indicated by a third identifier selected by the terminal,
The first DM-RS antenna port is a DM-RS antenna port belonging to the PDSCH transmission resource allocated by the DL DCI format including the QCL information
A method of establishing a base station. 16. The method of claim 15,
Wherein each of the plurality of third identifiers and each of the plurality of fourth identifiers forms a pair according to a sequence included in the second CSI process setting information,
The UE measures channels for a plurality of beams using CSI-RSs of a plurality of CSI-RS antenna ports corresponding to the plurality of third identifiers, Measuring interferences for the plurality of beams at a resource defined for a plurality of CSI-RS antenna ports corresponding to a fourth identifier, selecting at least one of the plurality of beams using the measured channels and interferences, The CSI for each of the selected beams is measured
A method of establishing a base station. 20. The method of claim 19,
Wherein the step of receiving the measured CSI according to the second CSI process setting information comprises:
Receiving a third identifier corresponding to the selected one of the plurality of third identifiers from the terminal along with the CSI for the selected beam if the selected beam is singular; And
Receiving a bitmap representing a third identifier corresponding to the selected one of the plurality of third identifiers from the terminal along with the CSI for the selected beam if the selected beam is multiple;
A method of establishing a base station.

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