WO2012141421A1 - Device and method for transmitting/receiving channel state information in a communication system - Google Patents

Abstract

The present invention relates to a wireless communication system, and more particularly, to a method for transmitting/receiving Channel State Information (CSI) in a communication system in which one terminal simultaneously communicates with at least two transmitting terminals. Standard signal configuration information for CSI measurement on at least two transmitting terminals and information for indicating a target transmitting terminal, i.e. a CSI feedback target, are transmitted to a terminal through additional signaling, and the terminal measures CSI on a specific transmitting terminal by using the information and provides feedback. According to an embodiment, in a communication system (i.e. a heterogeneous communication network) where one terminal simultaneously transmits/receives a signal to/from at least two transmitting terminals, an operation for obtaining CSI on at least one transmitting terminal is performed aperiodically.

Description

Apparatus and method for transmitting / receiving channel state information in communication system

The present invention relates to a communication system, and in particular, in a communication system in which two or more multiple transmitters can simultaneously transmit and receive signals with a terminal, channel state information (hereinafter referred to as channel state information or CSI) of each transmitter is referred to. It relates to a method of transmitting and receiving.

In the current mobile communication system, as a high-speed large-capacity communication system capable of transmitting and receiving various data such as video and wireless data beyond voice-oriented services, there is a demand for developing a technology capable of transmitting large-capacity data corresponding to a wired communication network. In addition, there is a need for an appropriate error detection method that can improve system performance by minimizing the reduction of information loss and increasing system transmission efficiency.

The high speed communication system operates on the basis of detailed information on a transport channel state. Therefore, in a communication system such as 3GPP, it is necessary to identify a channel state by using various reference signals and feed it back to the transmitter.

For example, when one terminal is allocated one downlink physical channel, the terminal may adaptively optimize the system by feeding back channel state information for each physical channel to the transmitting end. Signals such as Channel State Information-Reference Signal (hereinafter referred to as 'CSI-RS'), Channel Reference Signal (hereinafter referred to as 'CRS'), and Channel Quality Indicators (hereinafter referred to as 'CRS'). CQI ') and feedback information such as a precoding matrix index (hereinafter referred to as' PMI') may be used, and the transmitting end schedules a channel using such channel state related information.

In other words, the terminal receives a reference signal capable of measuring a specific channel or a channel state of the transmitter from the transmitter, and then measures channel state information (CSI) for the corresponding propagation channel and measures the measured channel. Feedback information about the status to the transmitter.

Meanwhile, unlike a general system in which a terminal transmits and receives data with one transmission terminal, a communication system in which a terminal transmits and receives signals with two or more transmission terminals has been discussed.

In such a communication system, the terminal should calculate and feed back different channel state information for two or more transmission terminals, but a plan for this is not currently considered.

Accordingly, the present invention is to propose a method for feedback between the aperiodic channel state information and the transmission mode through the communication system in the communication system for transmitting and receiving with two or more transmission terminals.

The present invention provides a method for transmitting and receiving channel state information in a wireless communication system.

Another embodiment of the present invention is to propose a method for transmitting and receiving channel state information in a communication system in which a terminal can simultaneously transmit and receive signals with two or more transmission terminals.

In another embodiment of the present invention, in a communication system in which a terminal can simultaneously transmit and receive signals with two or more transmitting terminals, the terminal simultaneously receives configuration information of a reference signal or a reference signal for channel state estimation for two or more transmitting terminals. Provides a way to send.

In addition, another embodiment of the present invention provides a method of signaling a message for indicating a target transmitter to which the channel state information of two or more transmitters should be fed back separately from the reference signal configuration information.

According to another embodiment of the present invention, CSI-RS configuration information of two or more transmission terminals is transmitted to the terminal as information in a table form, and as a separate signaling, CSI report for indicating a transmission terminal to be subjected to CSI feedback. It provides a method for transmitting the triggering (Reporting Triggering) information to the terminal.

According to another embodiment of the present invention, table information including CSI-RS configuration information for two or more transmitting terminals and CSI reporting triggering information for indicating a transmitting target to be subjected to CSI feedback are received from the transmitting terminal. After that, we propose a method of measuring and feeding back CSI for a specific transmitter accordingly.

An embodiment of the present invention is a method for receiving channel state information (CSI) in a communication system in which two or more transmitters can transmit and receive signals with one UE, and a specific transmitter has CSI-RS configuration for two or more transmitters. Transmitting table information including information to the terminal, transmitting CSI reporting triggering information to the terminal through signaling separate from the signaling of the table information, and determined according to the CSI reporting triggering information. It provides a CSI receiving method comprising the step of receiving the CSI of at least one target transmission terminal from the terminal.

Another embodiment of the present invention is a method of transmitting channel state information (CSI) by a terminal in a communication system in which two or more transmitting terminals can transmit and receive signals to and from a terminal. Receiving table information including RS configuration information, Receiving a CSI report triggering message for indicating one or more target transmission targets of the CSI measurement target of the multiple transmitters, With reference to the table information Checking the CSI-RS configuration information of the target transmitter, measuring the CSI using the CSI-RS of the target transmitter, and aperiodically transmitting the measured CSI of the target transmitter. A CSI transmission method is provided.

According to another embodiment of the present invention, a channel state information (CSI) receiving apparatus in a communication system in which two or more transmitting terminals can transmit and receive signals with one terminal, and a plurality of terminals capable of simultaneously transmitting and receiving signals with a single terminal CSI-RS information generating unit for generating multiple table information including CSI-RS configuration information for the transmitting end of the CSI, and CSI reporting for indicating one or more target transmitting end to measure and report the CSI among the multiple transmitting end A CSI report triggering message generating unit generating a triggering message, a transmitter transmitting the generated table information and the CSI report triggering message to a terminal, and a CSI receiving unit receiving the CSI for the at least one target transmitting terminal from the terminal. It provides a CSI receiving apparatus.

According to another embodiment of the present invention, a channel state information (CSI) transmitting apparatus in a communication system in which two or more transmitting terminals can transmit and receive signals with one terminal, and includes CSI-RS configuration information for two or more multiple transmitting terminals. A table information receiver for receiving table information, a CSI report triggering message receiver for receiving a CSI report triggering message for indicating one or more target transmitters to be measured for CSI among the multiple transmitters, and the table information A CSI-RS configuration information confirming unit for confirming CSI-RS configuration information of the target transmitter, a CSI measuring unit for measuring CSI using the CSI-RS of the target transmitter, and the measured target transmitter Provided is a CSI transmitter including a CSI feedback unit for transmitting CSI aperiodically.

1 illustrates an example of a communication system to which an embodiment of the present invention may be applied.

2 is a diagram illustrating resource allocation of a CSI-RS which is a channel estimation reference signal.

3 is a flowchart illustrating a CSI receiving method according to an embodiment of the present invention.

4 illustrates an example of a fifth table and a sixth table according to an embodiment of the present invention.

FIG. 5 shows an example of a structure of physical downlink control channel (PDCCH) data when the CSI report triggering message according to the present embodiment has 2 bits or more.

6 is a table listing state information of the CSI report triggering message according to the present embodiment.

7 is a block diagram of a CSI receiving apparatus according to an embodiment of the present invention.

8 is an overall flowchart of a CSI transmission method performed by a terminal according to the present embodiment.

9 shows the configuration of a CSI transmitter according to the present embodiment.

Hereinafter, some embodiments of the present invention will be described in detail with reference to the accompanying drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible even though they are shown in different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

The wireless communication system is to provide various communication services such as voice and packet data, and generally includes a user equipment (hereinafter referred to as UE) and a transmission point.

In the present specification, a terminal or a UE is a comprehensive concept of a user terminal in wireless communication, and a mobile station (MS), a user terminal (UT), a subscriber station (SS) in GSM as well as a UE in WCDMA, LTE, and HSPA. It should be interpreted as a concept that includes both stations and wireless devices.

A transmitting end or a cell generally refers to all devices or functions or specific areas communicating with a terminal, and includes a Node-B, an eNodeB (evolved Node-B) hereinafter, and a sector. (Sector), Site, Base Transceiver System (BTS), Access Point, Relay Node, Remote Radio Head (hereinafter referred to as 'RRH') Can be.

That is, in the present specification, a base station or a cell should be interpreted in a comprehensive sense including all areas covered by a base station controller (BSC) in a CDMA, a NodeB of a WCDMA, etc., or a device or hardware / software for managing the same. , Megacell, macrocell, microcell, picocell, femtocell, relay node, RRH and the like can be used in the same concept.

In addition, in the present specification, all devices communicating with the terminal may be referred to as a “transmission point” in the sense of transmitting information to the terminal, and the transmission terminal may mean a base station or a cell. In addition, it refers to all types of devices capable of communicating with one terminal, such as a radio remote head (RRH), a sector of a macro cell, a site, another micro cell such as a femtocell, a picocell, and the like connected to a transmission terminal. It is used as a comprehensive concept.

In this specification, the terminology of a terminal and a transmitter is used in a generic sense as two transmitting and receiving entities used to implement the technology or technical idea described in the present specification, and is not limited by the term or word specifically referred to.

On the other hand, there is no limitation on the multiple access scheme applied to the wireless communication system. Various multiple access techniques such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), OFDM-FDMA, OFDM-TDMA, OFDM-CDMA Can be used.

The uplink transmission and the downlink transmission may use a time division duplex (TDD) scheme transmitted using different times, or use a frequency division duplex (FDD) scheme transmitted using different frequencies, or both. A hybrid division duplex (HDD) system, which is a complex form of the system, may be used.

Embodiments of the present invention include resource allocation in the fields of asynchronous wireless communication evolving into Long Term Evolution (LTE) and LTE-advanced through GSM, WCDMA, HSPA, and synchronous wireless communication evolving into CDMA, CDMA-2000, and UMB. Can be applied to The present invention should not be construed as being limited or limited to a specific wireless communication field, but should be construed as including all technical fields to which the spirit of the present invention can be applied.

A wireless communication system to which an embodiment of the present invention is applied may support uplink and / or downlink HARQ, and may use CQI, which is a channel quality indicator, for link adaptation. In addition, multiple access schemes for downlink and uplink transmission may be different from each other. For example, downlink uses Orthogonal Frequency Division Multiple Access (OFDMA), and uplink uses Single Carrier-Frequency Division Multiple Access (SC-FDMA). ) Is the same as can be used.

The layers of the radio interface protocol between the terminal and the network are based on the lower three layers of the Open System Interconnection (OSI) model, which are well known in communication systems. The physical layer may be divided into a second layer (L2) and a third layer (L3), and the physical layer belonging to the first layer provides an information transfer service using a physical channel.

Meanwhile, in an example of a wireless communication system to which an embodiment of the present invention is applied, one wireless frame may include 10 subframes, and one subframe may include two slots.

The basic unit of data transmission is a subframe unit, and downlink or uplink scheduling is performed on a subframe basis. One slot may include a plurality of OFDM symbols in the region of the time axis and a plurality of subcarriers or subbands in the region of the frequency axis.

For example, a subframe consists of two time slots, and each time slot has seven symbols (extended cyclic prefix) when a normal cyclic prefix (hereinafter, referred to as a normal CP) is used in the time domain. 6 or 3 symbols in the case of using a cyclic prefix (hereinafter referred to as an extended CP)) and a bandwidth of 180 kHz (typically one subcarrier has a bandwidth of 15 kHz in the frequency domain), and thus, 180 kHz bandwidth is 12 Subcarriers corresponding to one subcarrier). Thus, a time-frequency domain defined as one slot on the time axis and a bandwidth of 180 kHz on the frequency axis is referred to as a resource block (hereinafter also referred to as an RB) or a resource block group (RBG). It may be called, but is not limited thereto.

In addition, the transmission time of the subframe is divided into a TTI (transmission time interval) of 1.0 ms duration. The terms TTI and subframe may be used in the same sense, and one radio frame is 10 ms long and includes 10 TTIs.

TTI is a basic transmission unit, where one TTI includes two time slots of equal length, each time slot having a duration of 0.5 ms. The time-slot includes a plurality of long blocks (hereinafter, referred to as 'LB') corresponding to each symbol. LBs are separated by cyclic prefix (CP). In this case, the cyclic prefix includes the normal CP and the extended CP according to the length thereof. In the case of using the normal CP, the plurality of LBs includes seven in one time-slot. LBs contain six or three in one time-slot.

In total, one TTI or subframe may include 14 LB symbols when using a normal CP, and generally 12 LB symbols or 6 LB symbols in a special case when an extended CP is used. The present specification is not limited to such a frame, subframe or time-slot structure.

Each TTI or subframe is divided into 14 symbols (axis) for a normal CP or 12 (or 6) symbols for an extended CP in the time domain. Each symbol (axis) may carry one OFDM symbol.

In addition, the total system bandwidth of 20 MHz is divided or divided into subcarriers having different frequencies. For example, as mentioned above, a resource block includes a region consisting of one slot in the time domain and subcarriers corresponding to a bandwidth of 180 kHz in the frequency domain (typically, 12 subcarriers in the case of having a bandwidth of 15 kHz per subcarrier). Or it may be called a resource block (RB).

For example, a bandwidth of 10 MHz within 1 TTI may include 50 RBs in the frequency domain.

Each grid space constituting the resource block RB may be referred to as a resource element (hereinafter, referred to as a RE).

For example, in a resource region corresponding to a bandwidth of 180 kHZ as a subframe in the time axis and a region in the frequency axis, a normal CP) is used and a resource bandwidth of one subcarrier is 15 kHz. There may be a total of 14 (symbols) × 12 (subcarriers) = 168 REs in each region.

Meanwhile, in the LTE communication system, after a terminal receives a reference signal for estimating a channel state from a transmitting end or a cell, the terminal estimates a channel state between the corresponding transmitting end or a cell and itself and transmits the channel state information (CSI) to the transmitting end or Feedback to the cell.

At this time, reference signals for estimating the channel state transmitted by the transmitting end or the cell to the terminal include CSI-RS, which is a channel state information reference signal, and a channel reference signal (CRS), and channels transmitted by the terminal to the transmitting end. The state information CSI may include a channel quality indicator CQI, a precoding matrix index PMI, and a rank index RI ', but are not limited thereto.

Meanwhile, a communication system in which each cell or transmission stage is independently configured while having the same or similar level of coverage area may be called a homogeneous network, and a heterogeneous network as a concept different from the heterogeneous network. Can be defined as

The homogeneous network and the heterogeneous network will be described in more detail as follows.

In general, a cellular system utilizes radio resources that are limited in a manner in which multiple cells share the same frequency band. In a cellular system, a signal transmitted by a transmitter does not propagate more than a predetermined distance, and an area in which a signal propagated by each transmitter may be received is called a cell area or a cell coverage area.

On the other hand, in a heterogeneous network in which regions overlap, it is possible for each terminal to simultaneously receive or transmit signals and information from two or more transmission terminals.

Here, the transmitting end is a comprehensive concept including an eNB, a radio remote head (RRH), a relay node, and the like.

On the other hand, homogeneous through a scheduling scheme that designates a transmission terminal to communicate with each terminal and a band to be used by each terminal according to the distribution state of the terminal connected to the heterogeneous network and the channel state of each terminal. It can provide better communication quality than Genius network.

For example, if a terminal requesting high-speed information communication is installed in an area with a lot of RRHs, then the terminals distributed in the area are provided with communication through the RRH, and the terminals located in the area are relatively uplink and downlink. Since the communication environment is configured to have a high reception power, it is possible to receive a high-speed information transmission service using a small band, which increases the overall communication efficiency of the communication network.

In the case of a modern communication system, a system in which a terminal receives information from two or more transmission terminals at the same time or two or more transmission terminals are controlled by the same scheduler and delivers the information to the same terminal through cooperative communication, Such a communication system may also be referred to as a coordinated multi- or cooperative multi-point wireless communication system (hereinafter referred to as a 'CoMP system').

In the present specification, the term CoMP system or heterogeneous network is used as a generic term for a communication system in which a terminal (UE) can communicate with two or more transmission terminals simultaneously. The term or function of only a specific communication system and communication method is used. It should not be limited to.

In the case of introducing a CoMP system in such a heterogeneous network, each terminal performs communication in an environment of transmitting and receiving signals and information simultaneously with one transmission terminal, one RRH, and two or more RRHs or transmission terminals with the RRH. In addition, a higher scheduling gain can be obtained by performing scheduling to change the number of transmitting terminals (transmitting terminals or RRHs) and the number of transmitting terminals to be appropriately adapted to channel conditions and system conditions.

In the present specification, in a downlink communication system using a plurality of transmission terminals to communicate with a terminal, the terminal acquires channel state information using a reference signal of each transmission terminal and transmits the channel state information to the transmission terminal. By using a control signal, a method of using a CSI transmission scheme differently between a single transmission stage transmission mode and a multiple transmission stage transmission mode is proposed.

1 illustrates an example of a communication system to which an embodiment of the present invention may be applied.

The heterogeneous communication network as shown in FIG. 1 has one wide coverage area B0 having a wide coverage area (solid line display) and one or more cooperative transmission sites having a narrow coverage area (dotted line display) included in the coverage area of the wide area transmission end. (H0, H1) and the like.

Here, the wide area transmitting end may be an eNB of a macro cell, and the cooperative transmitting end may be RRH, but is not limited thereto, and includes all transmitting ends having the same identifier and simultaneously transmitting and receiving information to the same terminal as described below. It is a comprehensive concept.

Hereinafter, for convenience, an eNB as a wide area transmission end and an RRH as a cooperative transmission end will be described as an example, but are not limited thereto.

In the communication system as shown in FIG. 1, as a scheme for switching downlink communication (transmission) without a handover process, an eNB and a plurality of RRHs have a network ID (cell ID) having the same identifier. And the RRH may use different radio resources to transmit CSI-RS, which is a channel estimation reference signal, and may allow each terminal to recognize a transmitting end communicating with itself using the above scheme. As such, each terminal may perform cooperative communication with the eNB and the RRH alone or with the eNB and the RRH.

2 is a diagram illustrating resource allocation of a CSI-RS which is a channel estimation reference signal.

In various current communication systems, various reference signals are used to provide the counterpart device with information about a communication environment through uplink or downlink.

For example, in the LTE system, which is one of mobile communication methods, CRS, which is a reference signal, is transmitted every subframe in order to identify channel information during downlink transmission.

At this time, the CRS is differently allocated to the four antennas in time / frequency according to the maximum number of antenna ports 4 supported by the downlink of the LTE system and transmitted.

Next-generation communication technologies such as LTE-Advanced, which are currently under development, can support up to eight antennas in the downlink, and thus, in order to grasp channel information during downlink transmission, there is a limit to the CRS defined only for the existing four antennas. For this purpose, the CSI-RS reference signal is newly defined to identify channel state information of up to eight antennas.

In other words, a communication system using up to 8 × 8 multiple input multiple output antennas (MIMO) is discussed in both a transmitting and receiving end, and different CSI-s are used for each antenna port or antenna layer through which a user terminal receives or transmits signals. RS must be transmitted.

The CSI-RS is allocated for each cell by one RE for each antenna port in an area of 12 subcarriers corresponding to one resource block (RB) on a frequency axis in every duty cycle on a time axis. .

That is, up to eight REs are allocated and transmitted for a total of eight antenna ports. At this time, the predetermined period T _CSI-RS corresponds to a multiple of 5ms of time consisting of five subframes, and specifically, T _CSI-RS may be 5, 10, 20, 40, 80ms, etc. It is not.

If the predetermined period is 5ms, the CSI-RS is transmitted in a total of two subframes among 10 subframes in one radio frame corresponding to 10ms. Therefore, if only the CSI-RS pattern for one subframe is defined, the other subframe may be allocated with a certain period.

On the other hand, CSI-RS transmission and channel state measurement through it may be made periodically as described above, but may be performed aperiodically at the request of the transmitter.

In the currently discussed communication system, aperiodic channel information feedback can be requested to the UE using downlink control information (hereinafter referred to as 'DCI'), and aperiodic in DCI format 0/4 or the like. In order to request the channel information transmission, one or two bits of information are included in the DCI information and transmitted to the terminal.

Then, the terminal receiving the DCI measures the channel state information (CQI, PMI, etc.) from the CSI-RS, etc. according to the request and transmits to the transmitting terminal aperiodically.

In particular, DCI format 4 is used for scheduling a physical uplink shared channel (PUSCH) in one uplink cell having a multi-antenna transmission mode, and is 1 or 2 bits as an aperiodic channel state report request. Contains the CQI Request field. (2 bits are used only when the terminal consists of one or more downlink cells)

On the other hand, a communication system using up to 8 × 8 multiple input multiple output antennas (MIMO) has been discussed in both transmitting and receiving stages, and since a different CSI-RS must be transmitted for each antenna port or antenna layer, the transmitter has a total of eight antenna ports. The CSI-RS for the CSI-RS should be allocated to be distinguished in the time-frequency domain, and in particular, the CSI-RS needs to be allocated to be distinguished for each cell in a multi-cell environment.

In the present specification, the antenna layer refers to a data layer that can be logically simultaneously transmitted to multiple antenna ports in a transmitting terminal or a mobile communication terminal. However, data of each antenna layer may be the same or different. Therefore, the number of antenna layers may be equal to or smaller than the number of antenna ports. On the other hand, the antenna port may mean an antenna physically configured in the transmission terminal or the mobile communication terminal, but is not limited thereto.

Hereinafter, although described with reference to the antenna port, it may be applied to the antenna layer unit or the physical antenna reference.

The subframe through which the CSI-RS is transmitted may be referred to as a “CSI-RS subframe” or a “CSI-RS subframe”, and the CSI-RS subframe may be referred to an upper layer through an index or a parameter I _CSI-RS . It can be configured by. I _CSI-RS denotes a cell-specific subframe configuration period T _CSI-RS (= 5, 10, 20, 40, 80 ms) and ΔCSI-RS (= 0 to T _CSI-RS −1) which is a subframe offset.

The CSI-RS pattern in which the CSI-RS is mapped to one subframe includes a frame structure (hereinafter referred to as FS), whether a cyclic shift (CP) is normal or extended, and an antenna Can be defined according to the number of ports (one of two, four, eight).

Information on the CSI-RS pattern (REs for CSI-RS transmission, that is, information on time / frequency resource location) in one subframe is transmitted by an upper end, and the CSI-RS pattern is specifically a normal CP. In the case of using, the number of CSI-RS transmit antennas is 8 (= 5 mandatory + 3 optional) patterns, 8 (16 (= 10 + 6) patterns, 1 or 2 patterns In this case, 32 (= 20 + 12) patterns exist, and in consideration of the maximum 32 patterns, signaling is performed for each cell at the upper end with 5 bits.

In the case of using an extended CP, when the number of CSI-RS transmit antennas is 8, 7 (= 4 + 3) patterns, when 4, 12 (= 8 + 6) patterns, one or two In this case, 28 (= 16 + 12) patterns exist, and in consideration of the maximum of 28 patterns, signaling is performed for each cell at the upper end with 5 bits.

In the above, the expression method of the number of patterns is expressed as the total number of patterns (= mandatory case applied to both FDD / TDD + optional case applied to TDD).

FIG. 2 is defined as Mandatory applied to both FS1 (FDD) and FS2 (TDD), and illustrates a possible CSI-RS pattern when each has a normal CP. 8, 4 cases. (4 cases are omitted for convenience)

As shown in FIG. 2, when the antenna port has 8 (antenna port numbers 0 to 7) as a general case having a normal CP, it may have a total of 5 CSI-RS patterns up to a patterns to e patterns. .

On the other hand, the CSI-RS pattern when the number of CSI-RS antenna ports is two, four instead of eight is configured in a nested structure when the number of CSI-RS antenna ports is eight.

That is, the pattern when the number of CSI-RS antenna ports is four is composed of patterns divided within each specific pattern when the number of CSI-RS antenna ports is eight, so the total number of patterns is CSI-RS antenna This is doubled when the number of ports is eight. The pattern when the number of CSI-RS antenna ports is two is also composed of the divided patterns within each specific pattern when the number of CSI-RS antenna ports is four, so the total number of patterns is the number of CSI-RS antenna ports. It is twice as many as four.

For example, there are five CSI-RS patterns applied to the normal CP case in one subframe when the number of CSI-RS antenna ports is eight (a to e in FIG. 2), and CSI-RS antennas. When the number of ports is 4, the number is 10 (the patterns a to j in the right figure of FIG. 2), which is twice that, and when the number of CSI-RS antenna ports is 2, the number is 20.

In a communication system in which multiple transmitting terminals having the same identifier (eg, cell ID) as shown in FIG. 1 can communicate with a single terminal, as described above, the channel state of each transmitting terminal is measured using CSI-RS and The feedback method to the transmitter may be implemented as follows.

That is, each transmitting end transmits information on its CSI-RS configuration, that is, information on the CSI-RS pattern and information on the number of antennas (ports) to the terminal through RRC (Radio Resource Control) signaling and the like, and physical It transmits its CSI-RS to the UE as downlink control channel (hereinafter, referred to as 'PDCCH') information. Then, the UE can estimate downlink channel state information between the corresponding transmitter and itself by measuring the reception state of the CSI-RS included in the PDCCH.

If it is assumed that B0 and H0 are used as a transmission terminal for communicating with the terminal U1 in the communication system of FIG. 1, the CSI-RS pattern is the d pattern and the number of antennas as the CSI-RS configuration information of the B0 eNB. Is 8, the CSI-RS configuration information of RRH H0 is assumed that the CSI-RS pattern is j pattern of the right side of Figure 2 and the number of antennas is four.

In this case, in the communication system as shown in FIG. 1, RRC signaling as shown in Table 1 below may be used as a method for transmitting CSI-RSs using different radio resources. In Table 1, (k ', l') represents the subcarrier number and symbol (axis) number of the first RE allocated to antenna port 0 among the CSI-RS, and n _s mod2 number represents the slot number constituting the corresponding subframe ( 0 or 1).

Table 1. RRC signaling table for CSI-RS pattern

That is, Table 1 is a diagram related to the RRC signal used when transmitting information about the CSI-RS transmission scheme to the terminal.

In the above assumption, each transmitting end transmits information on the CSI-RS pattern among its CSI-RS configuration information through RRC signaling, and information on the number of CSI-RS transmit antennas is system information (SI). It can transmit to the terminal.

Table 1 may be used to transmit the information on the CSI-RS pattern through RRC signaling. For example, the radio resource used by the eNB B0 for CSI-RS transmission is the first of the available radio resources for CSI-RS. Since the signal corresponding to the first CSI-RS port is transmitted from the radio resource corresponding to the highest frequency band of the first symbol, the CSI-RS transmission pattern is displayed as 0 or '00000', and is transmitted by RRH (H0). In the case of CSI-RS, a CSI-RS transmission pattern may be represented by 9 or '01001'.

In addition, B0 and H0 transmit information about 8 and 4, which are information on the number of antenna ports for CSI-RSs of the CSI-RS, to the terminal as system information such as system information block 2 (SIB2) separately from the RRC signaling.

That is, B0 and H0, each transmitting end, indicate the CSI-RS pattern to be transmitted by RRC signaling transmission of '00000' and '01001' to the UE, and transmits 8 and 4 information using system information. The number of antenna ports for CSI-RS is notified to the terminal.

When the UE receives the downlink information through the eNB, the transmitter B0 notifies the UE to measure the channel through the CSI-RS pattern of '00000' and 8 CSI-RS antenna ports through the RRC signal and system information. When the UE receives downlink information through the RRH, the RRH (H0) measures the channel through the CSI-RS pattern of '9 (01001)' and four CSI-RS antenna ports through the RRC signal and system information. You will be notified.

When the terminal receives downlink information from the eNB (B0) and the RRH (H0) at the same time, each transmitting end or one transmitting end should notify the terminal to measure the channel information using both of the CSI-RS. do.

In this method, when the transmitter is changed and the channel measurement scheme is changed accordingly, the transmitter is changed dynamically because information on the CSI-RS to be used for channel measurement must be transmitted to the UE in the form of RRC signaling and system information. It's hard to lose.

In particular, in the heterogeneous communication network as shown in FIG. 1, it is necessary to dynamically switch between a multiple transmission stage transmission mode and a single transmission stage transmission mode, and for this purpose, it is necessary to dynamically monitor channel conditions for the multiple transmission stages.

However, if the CSI-RS transmission and channel estimation are performed in the above-described manner, each time the RSI signaling or system information is required to be instructed to indicate the channel state estimation by the CSI-RS of each of the various transmission stages, it is dynamically performed. This is difficult, especially if this process is performed aperiodically.

Accordingly, the present specification provides a method for dynamically measuring channel state information of one or more transmission terminals in a communication system in which two or more transmission terminals simultaneously transmit and receive signals with one terminal.

In an embodiment of the present invention, in a communication system in which two or more transmitters can simultaneously transmit and receive signals with one UE, the transmitter includes simultaneously reference information (CSI-RS, etc.) configuration information for two or more transmitters. The information is transmitted to the terminal, and through the separate signaling, the terminal transmits information for determining which transmission terminal (1 or 2 or more transmission terminals) to measure and report CSI and CSI report triggering information to the terminal. .

Hereinafter, an embodiment of the present invention will be described in detail.

3 is a flowchart of a CSI receiving method according to an embodiment of the present invention, but is preferably performed by one or more of the transmitting terminals, but is not limited thereto.

In the embodiment of FIG. 3, in a communication system in which two or more transmitting terminals can simultaneously transmit and receive signals with one terminal, the specific transmission terminal includes table information including CSI-RS configuration information for two or more multiple transmitting terminals. Transmitting to the terminal (S310), transmitting CSI reporting triggering information to the terminal through signaling separate from the signaling of the table information (S320), and one or more targets determined according to the CSI reporting triggering information. And receiving the CSI for the downlink channel of the transmitter from the terminal (S330).

The table information is data including CSI-RS configuration information for each of two or more transmission terminals, that is, CSI-RS pattern information and antenna number information, and may be transmitted to the terminal through a single signaling such as RRC signaling, but is not limited thereto. It may not be, but may be transmitted to the terminal through two or more signaling.

For example, the table information includes a first table including CSI-RS pattern information for two or more transmitting terminals and second table information including information about the number of CSI-RS transmit antenna ports for two or more transmitting terminals. The first table is transmitted through RRC signaling and the second table information is transmitted to the terminal through SI (System Information) signaling.

In addition, the table information may include state information in a form in which CSI-RS configuration information of two or more transmission terminals is combined, in addition to CSI-RS configuration information for each of two or more transmission terminals. That is, the table information may include a state for indicating CSI reporting to two or more transmitting terminals by expressing two or more transmitting CSI-RS configuration information in addition to the status information indicating the CSI-RS configuration information of each transmitting terminal. Can be.

In the present specification, “table information” is a term used for convenience and may be replaced with another term, and includes all types of information simultaneously including CSI-RS configuration information (pattern information and / or antenna number information) for two or more transmission terminals. Inclusive meaning.

The CSI reporting triggering information may be signaled to the UE by the PDCCH, but is not limited thereto. The CSI reporting triggering information may be configured with 1 bit to n bit information, and the meaning of each bit is as follows. Will be explained again.

The CSI reporting triggering information is a request message for measuring and transmitting CSI from CSI-RS for one or more transmitters among two or more transmitters included in table information transmitted to the UE. The CSI report triggering information may be replaced with another term having an equivalent concept. The CSI reporting triggering information is a message instructing the UE to report CSI aperiodically, and may be information included in the DCI of the PDCCH, but is not limited thereto.

In the present specification, as one example of the CSI report triggering information, an expression called a CSI report triggering message may be used.

Meanwhile, the two or more transmitters may include one wide transmitter (such as eNB) and one or more cooperative transmitters (such as RHR), and the table information and CSI report triggering information may be transmitted to the UE. It can transmit, but is not limited thereto. In this case, the CSI report for one or more specific transmitters may also be configured as a wide area transmitter, but is not limited thereto. Of course, when the currently connected transmitter is the cooperative transmitter, the transmission of the table information and the CSI report triggering information and the CSI report may be performed between the cooperative transmitter and the terminal.

The embodiment of FIG. 3 will be described on the assumption that the conditions similar to those of FIGS. 1 and 2 are as follows.

That is, it is assumed that B0 and H0 are used as transmission terminals for communicating with the terminal U1 in the communication system of FIG. 1, and the CSI-RS pattern is the d pattern and the number of antennas as the CSI-RS configuration information of the B0 eNB. Is 8, the CSI-RS configuration information of RRH H0 is assumed that the CSI-RS pattern is j pattern of the right side of Figure 2 and the number of antennas is four.

 In this case, according to the conventional method described above, the pattern information '00000', which is the CSI-RS configuration information of B0, the antenna number information 8, the pattern information '01001', which is the CSI-RS configuration information of H0, and the antenna number information 4 are separate Each signal is transmitted to the terminal through signaling.

However, in the embodiment of FIG. 3, the CSI-RS configuration information of the multiple transmission terminals B0 and H0 is simultaneously transmitted to the terminal as one piece of information (such as in the form of table information).

More specifically, the table information may be implemented in one of four methods of the first to fourth types as follows, but this is merely an example and is not limited to the following methods.

1-1. First form of table information

The first form includes first table information consisting only of CSI-RS pattern information and second table information consisting only of CSI-RS antenna number information among CSI-RS configuration information of two or more transmission terminals.

That is, in the above assumption, the first table information is [0 9] and the second table information is [8 4].

In this case, the first table information including the CSI-RS pattern information of the two or more transmitting terminals may be transmitted to the terminal through RRC signaling, and the second table including the CSI-RS transmitting antenna port number information of the two or more transmitting terminals. The table information may be transmitted to the terminal as system information (SI), but is not limited thereto. For example, both the first and second table information may be transmitted to the terminal through RRC signaling.

1-2. Second form of table information

의 형태일 수 있다.The second type of table information includes all of the CSI-RS configuration information for each of two or more transmission terminals at once.

It may be in the form of.

That is, the second type of table information includes CSI-RS configuration information (pattern information 0 and antenna number information 8) of the first transmitting end and CSI-RS configuration information (pattern information 9 and antenna number information 4) of the second transmitting end. Can be configured as one transmission unit.

의 형태일 수도 있을 것이다.Of course, the data order of the table information of the second type is not limited to the above example, for example, the CSI-RS pattern information of the first transmitting end, the CSI-RS pattern information of the second transmitting end, and the first transmitting end. Is the order of antenna number information and antenna number information of the second transmitter.

It may be in the form of.

The second type of table information may be transmitted to the terminal through RRC signaling or the like, but is not limited thereto and may be transmitted to the terminal through other signaling.

1-3. Third form of table information

형태로 테이블 정보를 구성하는 것이다.The third type of table information includes information on a combination or grouping of two or more transmission terminals in addition to CSI-RS configuration information for each of the two or more transmission terminals.

Form table information.

That is, in addition to the CSI-RS configuration information for each transmitting end, it includes data representing the CSI-RS configuration information of two or more grouped transmitting ends simultaneously.

0/8 is CSI-RS configuration information (pattern information 0 and antenna number information 8) of the first transmitting end B0, and 9/4 is CSI-RS configuration information (pattern information 9 and number of antennas of the second transmitting end B0). Information 4) and '0/8, 9/4' are data representing the CSI-RS configuration information of the first and second transmission terminals at once.

Using the table information of the third form, in addition to indicating the CSI transmission of each of the two or more transmission terminals, there is an effect that it can be instructed to feed back the CSI for the two or more transmission terminals at the same time.

For example, in the above example, the first and second values indicate channel state measurement according to one CSI-RS configuration, and the third value indicates channel state measurement according to two CSI-RS configurations.

Table information of the third type may be transmitted to the terminal through RRC signaling, but is not limited thereto, and may be transmitted to the terminal through other signaling.

1-4. Fourth form of table information

The fourth type of table information is composed of third table information including CSI-RS configuration information for each of two or more transmission terminals, and information on CSI-RS combination or grouping as separate fourth table information.

이고, 제4테이블 정보는

형태일 수 있다.In the above example, the third table information is

And the fourth table information is

It may be in the form.

The first value of the fourth table information 0 indicates channel state measurement and CSI feedback according to the CSI-RS configuration of the first transmitting end B0, and the second value of 1 indicates the CSI-RS configuration of the second transmitting end H0. According to the channel state measurement and CSI feedback, and the third value '0, 1' indicates the CSI feedback of both the first transmitter and the second transmitter.

In a fourth aspect, the third table information and the fourth table information may be transmitted to the terminal through the same signaling or separate signaling. For example, the third table information may be transmitted to the terminal through RRC signaling, and the fourth table information may be transmitted to the terminal through separate signaling such as RRC signaling or SI transmission signaling (such as PBCH transmission).

1-5. Fifth Form of Table Information

On the other hand, in the fifth form of the table information, a bitmap format may be used. For example, a plurality of CSI-RS configuration information is defined as a fifth table, which is one table, and bitmap information including each bit or each group or combination thereof as one bit, and each bitmap information And a sixth table which is a bitmap table defined as a bitmap indicator for indicating. At this time, each of the CSI-RS configuration information of the antenna port number, CSI-RS pattern, CSI-RS sequence initial value, PDSCH power offset value, CSI-RS transmission subframe information It may include one or more.

As an example of the fifth form, it may be defined as a fifth table such as A of FIG. 4 and a sixth table such as B of FIG. 4. That is, as shown in FIG. 4A, the fifth table includes five CSI-RS configuration information, such as CSI-RS configuration A to CSI-RS configuration E, and is a bitmap table. In the present invention, four 5-bit bitmap information (00000, 10101. 01010, 11111) in which each of five CSI-RS configuration information is mapped to one bitmap, and bitmap indicators (00 to 11) indicating each bitmap information ) Is matched. The bitmap indicator in the sixth table may be used as a 'CSI report triggering message' as described below, which will be described later. Each bitmap information (5 bits) of the sixth table is information indicating whether to perform aperiodic CSI reporting on each of the plurality of CSI-RS configuration information constituting the fifth table. For example, bitmap information 1010 indicates that CSI is measured and reported for the first, third, and fifth CSI-RS configuration information of the fifth table (A of FIG. 4).

Of course, the order of the CSI-RS configuration information indicated by each bit of each bitmap information may be in the forward order or in the reverse order. That is, although the CSI-RS configuration information indicated by the first '1' in the bitmap information '10101' may be the first of the CSI-RS configuration information of the fifth table (A in FIG. 4), the last CSI-RS configuration information may be the first CSI-RS configuration information. RS configuration information may also be indicated.

As a modification of the fifth aspect, the table information is defined in the form of a fifth table such as A of FIG. 4, and the bitmap information is simply defined as 2 or 3 bits, and then each bit of the bitmap information is defined. Two or more CSI-RS configuration information may be indicated. In this case, the 2-bit or 3-bit bitmap information may be used as a 'CSI report triggering message' which will be described later, which will be described later.

For example, when a plurality of CSI-RS configuration information is transmitted to the terminal through the fifth table information as shown in FIG. 4A, CSI is defined as 2-bit bitmap information 'XY' that the transmitting terminal notifies the terminal. The first bit 'X' of the report triggering message is defined to trigger aperiodic CSI and report on the first to third CSI-RS configuration information of the fifth table, and the second bit 'Y' is the fifth table. The CSI-RS configuration information of the CSI-RS configuration information can be defined to trigger aperiodic CSI, reporting.

That is, m CSI-RS configuration information (m is an integer of 2 or more) is defined as a fifth table, and the CSI reporting triggering message is defined as bitmap information having a bit number less than m, and at least one of the bitmap information is defined. Bit can be used to trigger CSI reporting on two or more CSI-RS configuration information simultaneously.

Of course, in this example, the bitmap information does not necessarily need to be less than m bits, and may be defined as the same number of bits as the number m of CSI-RS configuration information included in the fifth table.

In addition, bitmap information having the same number of bits as the number of CSI-RS configuration information included in the fifth table may be directly used as a 'CSI report triggering message'. That is, in the fifth form, 5-bit bitmap information for indicating each of the five CSI-RS configuration information included in the fifth table without directly defining the sixth table may be used as the CSI report triggering message. For example, after delivering the fifth table as shown in A of FIG. 4 to the terminal, and then transmitting the CSI report triggering message, which is 5 bit bitmap information such as '10101', to the terminal through separate signaling, the terminal receives the fifth table. To report the CSI for the 1, 3, 5th CSI-RS configuration information of the.

In addition to the signaling of the table information, apart from the step S310 in which the CSI-RS configuration information for two or more transmission terminals (and a combination or grouping thereof in some cases) is transmitted to the terminal according to the first to fifth aspects, etc. Transmitting the CSI report triggering information or the CSI report triggering message to the terminal through signaling (S320).

Hereinafter, a detailed configuration of the CSI report triggering information will be described.

As described above, the CSI report triggering information or the CSI report triggering message is reported or transmitted aperiodically by measuring the CSI from the CSI-RS for one or more transmitters among two or more transmitters included in the table information transmitted to the UE. As a request message, it may be replaced with another term as long as it has an equivalent concept, and may be information included in the DCI of the PDCCH, but is not limited thereto.

Examples of the number and configuration of bits of the CSI report triggering message can be roughly classified into a case where a carrier aggregation (hereinafter, also referred to as "CA") environment is considered and a case where it is not.

First, the CA technology will be described.

In contrast to a communication system using a single carrier (carrier) consisting of one frequency band to date, in a recently discussed wireless communication system, a plurality of component carriers (hereinafter referred to as "component carrier" or "CC") It is discussed how to use.

That is, in a new communication system that is recently discussed, a discussion is being made to expand bandwidth to satisfy a required performance, and a unit carrier that an existing communication terminal can have for the bandwidth extension is defined as a component carrier (CC). In addition, a scheme of using up to N of these CCs has been discussed.

That is, a conventional 20 MHz component carrier can be bundled into a plurality of components, and for example, five (N = 5) component carriers can be bundled and extended to have a bandwidth of up to 100 MHz. Thus, a plurality of component carriers can be used. The technology that can be bundled to use is called carrier aggregation technology (CA). The frequency bands that can be allocated as component carriers may be continuous or discontinuous.

However, this is an embodiment according to the process of implementing the system, and may be set to have a bandwidth of 20MHz or more according to the configuration of the system.

In relation to the carrier integrated technology (CA), a number of component carriers are classified into three types according to characteristics: backwards compatible carrier, non-backwards compatibility carrier, and extension carrier. Can be.

Meanwhile, in the communication system currently discussed, DCI can be used to request aperiodic channel information feedback to the UE. In DCI format 0/4, etc., 1 or 2 bits of information are transmitted to DCI information to request aperiodic channel information transmission. It can be included and transmitted to the terminal. In addition, in a CA environment in which the UE may configure two or more downlink cells or CCs, 2-bit information of DCI format 4 may be used.

That is, in a CA environment, the terminal may configure and use two or more CCs, and therefore, in order to indicate which CCS information is aperiodically fed to, the DCI format 4 transmitted through the PDCCH 4 2 bits of can be used.

For example, if 2 bits, which is a CQI request field of DCI format 4, is 00, this means that aperiodic CSI (which may be CQI) is not transmitted. If 01, it is a primary CC (this is PCell or PCC). Asymmetric feedback) CSI of a non-periodic feedback, if 10, indicates to aperiodic feedback of one of the CSI of the secondary CC (which is equivalent to SCell or SCC). In case of 11, it may be instructed to transmit CSI of both PCC and SCC. Of course, it is not limited to this example, and other forms may be possible as long as each of the 2-bit CQI request fields can indicate to feed back CSI for one or more CCs.

Therefore, the CSI reporting triggering message used in the present embodiment may be classified into a case in which the CA environment described above is not taken into account (2-1 method below) and a case in which CA environment is considered (2-2 method below). And each is described below.

Considering the CA environment, the CA environment may simultaneously implement a function for instructing CSI padback according to CC configuration and a function for instructing CSI feedback according to CSI-RS configuration of two or more transmission terminals according to the present embodiment. The fact that the CA environment is not taken into consideration means that the CA and the multiplex transmission mode according to the present embodiment are less likely to be used at the same time, so that only the multiplex transmission mode according to the present embodiment is considered.

In practice, CA technology is used to increase bandwidth to a terminal having a good channel environment, whereas a multi-transmission transmission mode (for example, CoMP) is a spectrum that transmits data through multiple cells to a terminal having a poor channel state. As a technique introduced to improve the Spectrum Efficiency, both techniques have the feature that the intent of the introduction is reversed, so that if one is used, the other is likely not used.

Method 2-1 of CSI Reporting Triggering Message: Not Considering CA Environment: 1 ~ n bit

 If the CA is not considered, the CSI reporting triggering message may be divided into one bit and n bits of two or more bits.

In the case of 1 bit, when the CSI report triggering message is 0, the measured CSI is transmitted aperiodically using the CSI-RS configuration information of the corresponding transmitter performing periodic CSI reporting, and the CSI report triggering message is 1 In this case, it is possible to perform aperiodic CSI reporting according to the CSI-RS configuration showing the highest reception power other than the configuration currently used among all states (combination or combination of each transmitter and transmitter) represented in the table information. have.

For example, in the above example, when the UE measures the CSI for the CSI-RS pattern '00000' and the number of 8 CSI-RS ports and reports it periodically, 0 is received as the CSI reporting triggering message. The UE reports the aperiodic CSI using the CSI-RS currently being used for the periodic CSI measurement. However, when 1 is received as the CSI reporting triggering message, the UE reports aperiodic CSI according to the CSI-RS configuration that shows the highest received power in addition to the CSI-RS configuration currently used for periodic CSI reporting among the CSI-RSs specified in the table information. Can be done.

Of course, this is only one example, and differently set which transmission or transmission combinations to perform aperiodic CSI reporting based on the CSI-RS configuration in the case of 0 and 1 in the 1-bit CSI report triggering message, respectively. Could be.

Next, a case where the CSI report triggering message is n bits of 2 bits or more when the CA is not considered will be described.

5 illustrates an example of a structure of PDCCH data when the CSI report triggering message is 2 bits or more.

First, when the CSI report triggering message is 2 bits, it is illustrated as the case A of FIG. 5.

If the CSI reporting triggering message is 2 bits, CA is not considered. For example, if '00', aperiodic CSI reporting is not performed. If the value other than '00', aperiodic CSI reporting is performed. It can be displayed. For example, in the case of '01', it is instructed to feed back the measured CSI according to the CSI-RS configuration of the first transmission end (for example, B0, which is a wide area transmission end) in the above-described table information. In this case, the CSI may be set to report the measured CSI according to the CSI-RS configuration information displayed on the second table information.

As another example, when the CSI report triggering message is 2 bits, a total of four states can be expressed, but three states are actually used, and one of them does not perform aperiodic CSI reporting (no aperiodic). CSI-RS reporting), aperiodic CSI reporting for serving cell (or PDSCH transmitting cells), a non-serving transmitter or a transmitter that does not transmit PDSCH. It may also indicate the case of aperiodic CSI reporting for non-serving cell (or reporting set which dose not send PDSCH).

In addition, in the above example, one of the four states indicates aperiodic CSI reporting for both the serving transmitting end (ie, PDSCH transmitting cell) and the non-serving transmitting end (ie, non-PDSCH transmitting cell). Can be represented.

If the CSI report triggering message is 2 bits and does not consider the CA environment, the aforementioned aperiodic CSI request field (2 bits) of DCI format 4 may be used as the CSI report triggering message according to the present embodiment.

By doing so, it will be possible to selectively indicate the CSI report for the multiple transmitters according to the present embodiment without changing the data format according to the existing standard.

Of course, even if the CA environment is not taken into account, when the number of transmission terminals that need to perform CSI reporting is complicated, the table information may be composed of two or more bits of n-bit information.

For example, if the number of transmitting terminals transmitting the CSI-RS is three, the table information includes three values representing the CSI-RS configuration information of each transmitting terminal and two or more combinations or groups of CSI-RSs. The CSI report triggering message should be at least 3 bits because it includes a total of six data of three values simultaneously displaying RS configuration information.

In addition, as described with reference to A of FIG. 4 and B of FIG. 4, bitmap information may be used to designate a target for performing CSI reporting from among table information including CSI-RS configuration information of each of the plurality of transmission terminals. .

That is, as shown in FIG. 4A, a sixth table including bitmap information of up to m bits designated as one bit for each of the m CSI-RS configuration information included in the table information (the fifth table) and a bitmap indicator to indicate the same. May be transmitted to the terminal in advance, and the bitmap indicator may be used as a CSI report triggering message.

In addition, the CSI report triggering message itself may be defined as mbit or less bitmap information so that one or more of m CSI-RS configuration information included in the table information (the fifth table) is designated as one bit.

The CSI report triggering message may be included in the DCI of the PDCCH and transmitted, but is not limited thereto. The CSI report triggering message may be transmitted to the terminal through signaling of table information including CSI-RS configuration information for the multiple transmitters and separate signaling. Can be.

Method 2-2 of CSI Reporting Triggering Message: Considering CA Environment: 2 ~ n bits

 When considering CA, the CSI reporting triggering message includes a 1-bit delimiter and 2 or more bits of CSI report target indication information for distinguishing CA / multi-transmission transmission mode, and the current definition (DCI format 4 2 bits CQI Request) may be implemented in the case of including 2 bits or more information for indicating the CSI-RS configuration information of the CSI report target transmission terminal according to the present embodiment in addition to the 2 bits CC identification information.

A case in which the CSI report triggering message includes a 1-bit discriminator for distinguishing CA / multi-transmission transmission mode and CSI report target indication information of 2 bits or more is described as follows.

As in the case of FIG. 5B, when the CSI report triggering message includes a 1-bit delimiter for distinguishing CA / multi-transmission transmission mode and CSI report target indication information of 2 or more bits, when the 000 value is received, the aperiodic CSI Report is not performed, but a value other than 000 may be performed by performing aperiodic CSI reporting as follows.

The CSI report target indication information of two bits or more is used to indicate a CC (PCell or SCell) to transmit CSI in CA mode, and in the multi-transmission transmission mode, the CSI-RS configuration of a transmission end to transmit CSI is according to the present embodiment. It is used to indicate.

That is, according to the 1-bit discrimination factor for distinguishing CA / multi-transmission stage transmission mode, whether to report the conventional CSI for each CC as described above or based on the CSI-RS of one of the multiple transmission stages according to the present embodiment To indicate whether to report a CSI.

For example, when the 1-bit discriminator for distinguishing CA / multi-transmitter transmission mode included in the CSI report triggering message of 3 bits or more is 0, the following 2 bits are used for the aforementioned CC classification by operating in CA mode. If the above-described CSI report target indication information is used and the 1-bit discrimination factor is 1, the CSI-RS configuration information of the transmitting end to transmit the CSI is transmitted when transmitting multiplexing terminals according to the present embodiment. In this case, a method in which 2 bits or n bits indicate CSI-RS configuration information of a transmission terminal for transmitting CSI in a multi-transmission transmission mode may be implemented in the same manner as in the aforementioned 2-1 method.

As another embodiment, when the CSI report triggering message is 3 bits or more, it is possible to recognize that the CA is considered, and when it is 2 bits or less, the CSI report triggering message may be used in the 2-1 scheme without considering the CA.

In another embodiment of the second embodiment, the CSI-RS configuration information of the CSI-reporting destination according to the present embodiment is indicated in addition to the 2-bit CC classification information currently defined (2-bit CQI request in DCI format 4). A case of including two or more bits of information to be described is illustrated in FIG. 5C.

In this case, in addition to 'XX', which is already 2 bits (CCI request field in DCI format) for aperiodic CSI triggering in a CA environment, the CSI-RS configuration information of the CSI-reporting destination according to the present embodiment is indicated. This is the case of using more than two bits of information (two bits after XX in FIG. 5C).

The method of using two or more bits of information for indicating CSI-RS configuration information of the CSI-reporting transmission end may be the same as that of the aforementioned method 2-1.

As another embodiment considering the CA mode and the multi-transmitter transmission mode (CoMP mode) according to the present embodiment at the same time, so as to include both the information for CC classification in the CA environment and the transmission terminal identification information in the multi-transmission transmission mode. It is also possible to set four or more states and have two or more bits of the CSI report triggering message indicate one of the various states.

6 is a table listing state information of the CSI report triggering message according to the embodiment.

That is, when the four states (00 to 11) as shown in Fig. 6 (None), each of the non-periodic CSI report (None), PCell (main component carrier) instructs the CSI reporting according to the first CSI-RS configuration (1 ^st CSI) -RSConfigurationatPCell), if indicated by the PCell the CSI reported according to the first and second CSI-RS configuration at the same time ^{(1 st and2 nd CSI-RSConfigurationatPCell} ), the PCell the CSI according to the first CSI-RS configuration, the SCell 0 1 and SCell state indicating to report CSI according to the second CSI-RS configuration information may be to indicate the (1 ^st & 2 ^nd RSConfigurationatPCell CSI-CSI-RSConfigurationatSCell0andSCell1).

This is merely an example, and for example, other types of status indications may be matched with B of FIG. 6.

In FIG. 6B, the four states (00 to 11) are each non-periodic CSI reporting (None), a state indicating CSI reporting according to the first CSI-RS configuration of the CoMP target CC, and the second CSI-RS of the CoMP target CC. The CSI reporting according to the configuration is illustrated, and the CSI reporting according to the CSI-RS configuration pre-selected in the PCell and the SCell is illustrated.

That is, in the process of indicating aperiodic CSI and reporting using n (n is a value of 2 or more) bits, the following schemes may be used as a method of using 2 ⁿ kinds of triggering information that can be expressed through n bits.

1. For a UE on which CoMP is performed in a single CC, each information may indicate which CSI-RS configuration (s) to report on.

2. Which CSI-RS configuration (s) will be reported to which UE performs CoMP for multiple CCs under the assumption that aperiodic CSI reporting is performed for all CCs according to the same CSI-RS configuration. Can be directed.

3. For a UE that performs CoMP for a plurality of CCs or performs communication using a plurality of CCs and performs CoMP only in some of the CCs above, any of the CCs considering both CA and CoMP environments It may indicate whether to perform reporting on the CSI-RS configuration (s). Or may indicate information reporting on which CSI-RS configuration (s) of which CCs. Also, in the above specification, each triggering information (three information '01', '10', '11' if two bits are used) will report the 'any CC' and 'which CSI-RS configuration (s)'. Information on whether or not to indicate may be notified to the terminal by separate RRC signaling.

As described above, for a plurality of aperiodic CSI resources (CC configuration information and / or CSI-RS configuration information), such as CSI-RS configuration for two or more CCs, two or more transmission terminals, or when two CSIs are simultaneously transmitted. If the CSI is measured and reported simultaneously, the order of reporting can be determined as follows.

As a first method, all aperiodic CSI information is reported in the same subframe, and aperiodic CSI is listed according to the CC index order, and when the CC index is the same, the low index is represented in the CSI-RS configuration table information. That is, the CSI measurement result by the CSI-RS configuration that is arranged first in the table may be listed first.

Secondly, when the size of the uplink control information (UCI) including the CSI information exceeds the specific threshold as a result of the first method, the CSI measurement value may be divided and transmitted in two or more subframes.

In this specification, various ways of configuring table information (first to fifth forms) and various types of implementations of CSI report triggering messages (second-1 manner, second-2 manner, and detailed manners included therein) are described. As one example only, one of them may be selected according to the type of communication system or other factors, and in some cases, two or more methods may be combined and adopted.

The subject for transmitting the table information including the CSI-RS configuration information for the multiple transmitters and generating and transmitting the CSI reporting triggering message may be a wideband transmitter such as an eNB, but is not limited thereto. It may be a cooperative transmission end.

In addition, after the UE receives the CSI report triggering message and transmits the table information, CSI (CQI. PMI, CSI) based on the CSI-RS configuration information for one or more transmitters indicated by the CSI report triggering message with reference to the table information. RI, etc.) is measured and fed back to the transmitter. In this case, the transmitting end receiving the feedback CSI information is preferably a wide area transmitting end, such as an eNB, but is not limited thereto, and may be a cooperative transmission end or a plurality of transmitting ends. Also, the transmitting end receiving the fed back CSI information may be the transmitting end transmitting the table information or the CSI report triggering message, or may be another transmitting end.

For example, the wide area transmitter receives CSI for one or more target transmitters transmitted by the terminal in the above manner, and then switches whether the currently connected transmitter is switched to another transmitter (in the single transmitter transmission mode). It is possible to determine whether or not to switch between (transmission stage switching of) or multiple transmission stage transmission mode (CoMP) and a single transmission stage transmission mode (switching between a single transmitter transmission mode and CoMP mode).

7 is a block diagram of a CSI receiving apparatus according to an embodiment of the present invention.

The CSI receiver 700 according to an embodiment may be implemented in one of a plurality of transmission terminals in the heterogeneous network as shown in FIG. 1 or may be implemented in conjunction with the same.

The CSI receiving apparatus 700 according to an embodiment generates or stores table information including CSI-RS configuration information of a plurality of transmitting terminals capable of simultaneously transmitting and receiving signals with a terminal. An information generator 710, a CSI report triggering message generator 720 for generating a CSI report triggering message for indicating one or more target transmitters to measure and report CSI among multiple transmitters, and the generated table information And a transmitter 730 for transmitting a CSI report triggering message to the terminal, and a CSI receiver 740 for receiving CSI for the one or more target transmitters from the terminal.

In addition, the transmission mode switching unit 750 for switching the transmission mode using the CSI received from the terminal may be further included.

The multiple transmitter CSI-RS information generator 710 generates table information to include CSI-RS configuration information for two or more transmitters among a plurality of transmitters capable of simultaneously transmitting and receiving signals with a single terminal. The form of the table information may be one or more of the above first to fifth forms, but is not limited thereto.

As described above, the table information including the CSI-RS configuration information for the two or more transmission terminals is 1) CSI-RS configuration information of the two or more transmission terminals, consisting of only the CSI-RS pattern information, and CSI A first type including second table information consisting only of the number of RS antennas, 2) a second type including all of the CSI-RS configuration information for each of two or more transmitting terminals, and 3) each of two or more transmitting terminals In addition to the CSI-RS configuration information for the third form including the information on the combination or grouping (Grouping) of two or more transmitters at the same time, and 4) a third including CSI-RS configuration information for each of the two or more transmitters A fourth form comprising table information and information on CSI-RS combination or grouping as separate fourth table information, and 5) defining a plurality of CSI-RS configuration information as a fifth table as one table, Each of CSI-RS or its One or more of the fifth forms using bitmap information having one or more groups / combinations as one bit may be implemented, but is not limited thereto, and CSI-RS configuration information (ie, CSI-RS) for two or more transmission terminals. The pattern will not be limited as long as it includes pattern information or antenna port number information).

The CSI report triggering message generator 720 generates a CSI report triggering message, which is information for indicating at least one target transmitter to measure and report CSI among multiple transmitters, and the CSI report triggering message does not consider the CA environment. 2-1 may be configured in 1 to n bits, and 2-2 may be configured in 2 to n bits in consideration of a CA environment.

In particular, when 2 bits are used as the CSI report triggering message, the CQI request field (2 bits), which is a non-periodic CSI request field of the currently defined DCI format 4, can be used as the CSI report triggering message according to the present embodiment. It will be possible to selectively indicate the CSI report for multiple transmitters according to the present embodiment without changing the data format according to the current standard.

The transmitter 730 transmits the table information and the CSI report triggering message generated at 710 and 720 to the terminal, and the table information may be transmitted to the terminal through RRC signaling or system information (SI) transmission signaling. The report triggering message may be transmitted to the terminal by signaling such as DCI transmission of a PDCCH separate from the signaling of the table information, but is not limited thereto.

The CSI receiver 740 receives the CSI for the one or more corresponding transmitters from the terminal. That is, after the terminal receives the table information including the CSI-RS configuration information for the multiple transmitters described above and the CSI report triggering information indicating the target transmitter for transmitting the CSI, the CSI of the specific transmitter is transmitted from the two pieces of information. -Measure the CSI using the RS configuration information and transmit the measured CSI to the transmitting end, which may be a wide area transmitting end of the corresponding eNB (B0) or a cooperative transmitting end such as RRH (H0, H1). CSI receiver 740 receives the CSI.

In addition, although not shown, the CSI receiving apparatus according to the present embodiment receives the CSI for one or more target transmission terminals from the terminal and then switches the currently connected transmission terminal to another transmission terminal (single transmission terminal transmission mode). May further include a mode switching unit for determining whether to switch between a multi-transmission transmission mode (CoMP) and a single transmission transmission mode (switching between a single transmission transmission mode and a CoMP mode). will be.

8 is an overall flowchart of a CSI transmission method performed by a terminal according to the present embodiment.

The CSI transmission method of FIG. 8 may be performed by a terminal capable of transmitting and receiving signals simultaneously with two or more transmission terminals, but is not limited thereto.

In the CSI transmission method according to the present embodiment, a table information including CSI-RS configuration information of two or more multiple transmission terminals is received from a specific transmission terminal (S810), and one of the CSI measurement targets among the multiple transmission terminals is determined. Receiving the CSI report triggering message for indicating the target transmitter through the signaling in step S810 and signaling separate from the step S810 (S820), and confirms the CSI-RS configuration information of the target transmitter with reference to the table information. And a step (S840) of measuring the CSI using the CSI-RS of the target transmitter, and aperiodically transmitting the CSI of the measured target transmitter (S850). Can be.

Table information and CSI report triggering message including CSI-RS configuration information (CSI-RS pattern information and / or CSI-RS antenna port number information, etc.) for the two or more multiplexing terminals may be configured as described above. The detailed description is omitted to avoid duplication.

The signaling for transmitting table information in step S810 may be RRC signaling and / or system information transmission signaling, and the signaling for transmitting a CSI report triggering message in step S820 may be PDCCH transmission signaling, but is not limited thereto.

In addition, the CSI reporting triggering message may be included in a part of DCI information transmitted through the PDCCH, and in particular, may use a CQI request field value, which is an aperiodic CSI transmission request message of DCI format 4, and is implemented as a DCI field value defined separately. It could be.

In addition, the table information may be periodically transmitted through RRC signaling and the like, and transmission of the CSI report triggering message and corresponding CSI feedback may be performed aperiodically.

9 shows the configuration of a CSI transmitter according to the present embodiment.

The CSI transmitting apparatus of FIG. 9 may be implemented in a terminal capable of transmitting and receiving signals simultaneously with two or more transmission terminals, or may be implemented in conjunction with such a terminal, but is not limited thereto.

The CSI transmitter 900 according to the present embodiment includes a table information receiver 910 for receiving table information including CSI-RS configuration information of two or more multiple transmitters, and a CSI measurement target among the multiple transmitters. A CSI report triggering message receiver 920 for receiving a CSI report triggering message for indicating one or more target transmitters through signaling separate from the signaling of the table information, and CSI- of the target transmitter with reference to the table information. The CSI-RS configuration information checking unit 930 for checking RS configuration information, the CSI measuring unit 940 for measuring CSI using the CSI-RS of the target transmitter, and the measured CSI of the target transmitter are compared. It may be configured to include a CSI feedback unit 950 for transmitting periodically.

Among the configuration of the CSI transmitting apparatus 900, the configuration of the table information, the CIS report triggering message, the signaling method, and the like may be implemented according to the above-described embodiment, and detailed descriptions thereof will be omitted to avoid duplication.

Using the above embodiments, in a communication system (heterogeneous communication network, etc.) in which one terminal can simultaneously transmit and receive signals with two or more transmission terminals, channel state information (CSI) of one or more specific transmission terminals is aperiodically. It is possible to dynamically perform the operation of obtaining.

In addition, by dynamically checking the CSIs of multiple transmitters in a heterogeneous communication network, dynamic switching between the multiple transmitter (CoMP) mode and the single transmitter transmission mode, and dynamic switching of the serving transmitter in the single transmitter transmission mode. The effect is that it is possible.

 The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and variations without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application is filed with US Patent Act No. 119 on Patent Application No. 10-2011-0034872 filed with Korea on April 14, 2011 and Patent Application No. 10-2012-0011934 filed with Korea on February 6, 2012. Priority is claimed under section (a) (35 USC § 119 (a)), all of which is incorporated by reference in this patent application. In addition, if this patent application claims priority to a country other than the United States for the same reason, all its contents are incorporated into this patent application by reference.

Claims (13)

A method for receiving channel state information (CSI) in a communication system in which two or more transmitting terminals can transmit and receive signals with one terminal, Transmitting, by a specific transmitting end, table information including CSI-RS configuration information of two or more multiple transmitting ends to the terminal; Transmitting CSI Reporting Triggering information to the UE through a separate signaling different from the signaling of the table information; And receiving from the terminal the CSI of at least one target transmitter determined according to the CSI report triggering information. The method of claim 1, The table information is transmitted through RRC (Radio Resource Control) signaling or system information (System Information) transmission signaling, and the CSI report triggering information is transmitted through physical downlink control channel (PDCCH) signaling. Way. The method of claim 1, The table information includes CSI-RS configuration information for each of two or more multiple transmitters, and the CSI-RS configuration information is one or more of CSI-RS pattern information and antenna number information. The method of claim 3, The table information further includes information on a combination or grouping of CSI-RS configuration information for two or more transmission terminals, in addition to the CSI-RS configuration information for each of two or more multiple transmission terminals. The method of claim 1, The CSI report triggering information is a CSI receiving method, characterized in that the message indicating the target terminal to be transmitted to the terminal to transmit the CSI from the two or more transmitters included in the table information transmitted to the terminal. The method of claim 5, The CSI reporting triggering information is bit information of a predetermined length selected from 1 bit to n (≥ 2) bits when carrier aggregation (CA) is not considered. The method of claim 6, And the CSI report triggering information is 2 bits, and is included in downlink control information (DCI) of a physical downlink control channel (PDCCH). The method of claim 1, The CSI report triggering information is bitmap information generated to indicate one bit for one or more of CSI-RS configuration information for two or more multiple transmitters included in the table information. The method of claim 1, And transmitting the CSI report triggering information to the terminal and receiving the CSI of the target transmitter from the terminal are performed aperiodically. A method of transmitting channel state information (CSI) by a terminal in a communication system in which two or more transmitting terminals can transmit and receive signals with the terminal, Receiving table information including CSI-RS configuration information for two or more multiple transmission terminals from a specific transmission terminal; Receiving a CSI report triggering message for indicating one or more target transmitters that are subject to CSI measurement among the multiple transmitters; Confirming CSI-RS configuration information of the target transmitter by referring to the table information; Measuring CSI using the CSI-RS of the target transmitter; And, And aperiodically transmitting the measured CSI of the target transmitter. The method of claim 10, The table information is received through Radio Resource Control (RRC) signaling or System Information (SI) transmission signaling, and the CSI report triggering information is received through physical downlink control channel (PDCCH) signaling. The table information includes CSI-RS configuration information for each of two or more multiple transmission end. An apparatus for receiving channel state information (CSI) in a communication system in which two or more transmitting terminals can transmit and receive signals with one terminal, A multiple transmitter CSI-RS information generator for generating table information including CSI-RS configuration information for a plurality of transmitters capable of simultaneously transmitting and receiving signals with a single terminal; A CSI report triggering message generator configured to generate a CSI report triggering message for indicating one or more target transmitters to measure and report CSI among multiple transmitters; A transmitter for transmitting the generated table information and the CSI report triggering message to a terminal; And a CSI receiver for receiving CSI for the at least one target transmitter from a terminal. An apparatus for transmitting channel state information (CSI) in a communication system in which two or more transmitting terminals can transmit and receive signals with one terminal, A table information receiver configured to receive table information including CSI-RS configuration information of two or more multiple transmitters; A CSI report triggering message receiver configured to receive a CSI report triggering message for indicating one or more target transmitters that are CSI measurement targets among the multiple transmitters; A CSI-RS configuration information confirming unit which checks CSI-RS configuration information of the target transmission end by referring to the table information; A CSI measuring unit measuring CSI using the CSI-RS of the target transmission end; And a CSI feedback unit for aperiodically transmitting the measured CSI of the target transmitter.

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