KR20150135064A - Scheme for transmitting reference signal in wireless communication system - Google Patents

Abstract

The present invention relates to a communications method of user equipment (UE) in a cellular communications system, comprising operations of: receiving a channel state information reference signal (CSI-RS) transmitted according to a pattern in a resource grid determined based on a transmission scheme of a base station; measuring the state of a transmission channel with the base station by using the CSI-RS, and generating channel state information of the terminal and giving feedback; receiving a downlink signal including data and a cell-specific reference signal (CRS) from the base station; and estimating the transmission channel with the base station by using the CRS, and acquiring the data by using the estimated channel.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a reference signal transmission method in a wireless communication system,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present disclosure relates to a reference signal transmission technique in a wireless communication system, and to a reference signal transmission method and apparatus thereof in consideration of an interference signal in a cellular communication system.

In a next generation wireless communication system (for example, a long-term evolution-advanced (LTE-A) system), the cell coverage is much smaller than that of a conventional cellular environment, and a femtocell And a non-uniform cell distribution by operating various types of cells.

A user equipment (UE) is a device that not only receives a desired signal (or a request signal) from a serving cell but also an un-desired signal from an interfering cell Or " interfering signal "). In this environment, inter-cell interference is a major cause of degradation in performance due to packet errors of a user terminal.

In an LTE wireless communication system, a base station transmits a channel state information-reference signal (CSI-RS) signal so that the UE can measure channel quality from a serving cell before transmitting data to the terminal. A reference signal) can be transmitted. In addition, the BS may use CSI-IM (Interference Measurement) so that the UE can measure channel quality in consideration of a channel from a neighboring cell.

The UE determines CQI using CSI-RS and CSI-IM and feedbacks the channel quality information to the BS. The base station transmits data to the terminal based on the feedback. At this time, the BS transmits a CRS (Orthogonal Frequency Division Multiplex) signal in an OFDM (Orthogonal Frequency Division Multiplex) domain together with the data to estimate a channel (i.e., a channel of a request signal) Cell-specific reference signal.

In order to solve the interference problem in the wireless communication system, the channel state information of the interference signal must be accurately estimated.

Although the transmission scheme information of the interference signal can be estimated using the CSI-IM defined in the LTE wireless communication system, since the CSI-IM reuses the pattern of the CSI-RS designed for channel state information measurement, There is a limit in estimating the transmission scheme information of the interference signal. In order to overcome the limitations of the CSI-IM, the present disclosure proposes a new CSI-RS pattern considering the transmission scheme and maximizes the transmission scheme information estimation performance of the interference signal using the proposed CSI-RS pattern .

A next generation terminal (e.g., a Long-Tem Evolution-Advanced (LTE-A) UE) may remove the interfering signal from the received signal to reduce packet errors in the request signal. In order to remove the interference signal, the terminal can use not only the channel information of the interference signal but also the transmission scheme information of the interference signal. The UE can estimate the channel state information of the interference signal using the CRS transmitted from the interference cell. However, the next generation terminal requires transmission scheme information of the interference signal, and a new RS must be transmitted in the next generation wireless communication system. In this disclosure, a new RS for estimating transmission scheme information of an interference signal used by a next generation terminal for interference cancellation is proposed.

The present disclosure relates to a communication method of a user equipment (UE) in a cellular communication system, which includes receiving a CSI-RS (channel state information reference signal) transmitted according to a pattern on a resource grid determined based on a transmission method of a base station action; Measuring a transmission channel state with the base station using the CSI-RS and generating and feeding back channel state information of the terminal; Receiving a downlink signal comprising data and a cell-specific reference signal (CRS) from the base station; And estimating a transmission channel with the base station using the CRS and acquiring the data using the estimated channel.

The present invention relates to a method for communicating a base station in a cellular communication system, the method comprising: transmitting a CSI-RS (channel state information reference signal) to a mobile station according to a pattern on a resource grid determined based on a transmission scheme of the base station; Receiving channel state information of the UE measured using the CSI-RS; And transmitting a downlink signal comprising data and a cell-specific reference signal (CRS).

The present disclosure relates to a user equipment (UE) communicating in a cellular communication system, which receives a channel state information reference signal (CSI-RS) transmitted according to a pattern on a resource grid determined based on a transmission method of a base station, (CSI-RS), generates and feeds back channel state information of the UE, and receives downlink signals including data and a CRS (cell-specific reference signal) from the base station A control unit configured to estimate a transmission channel with the base station using the CRS and obtain the data using the estimated channel; And a transceiver for receiving the CSI-RS under the control of the controller, feeding back the channel state information, and receiving the downlink signal.

A base station communicating in a cellular communication system transmits a channel state information reference signal (CSI-RS) according to a pattern on a resource grid determined based on a transmission scheme of the base station, A control unit configured to receive the measured channel state information of the UE using the measured data and transmit a downlink signal including data and a cell-specific reference signal (CRS); And a transmitter / receiver for transmitting the CSI-RS under the control of the controller, receiving the channel status information, and transmitting the downlink signal.

According to the present disclosure, a terminal can determine accurate channel state information and thereby improve system capacity.

In addition, the UE can improve the estimation error performance of SFBC, SFBC-FSTD, and CDD-SM based transmission schemes. The UE can minimize False alarm detection error and Miss alarm detection error in an interference signal including at least one of SFBC, SFBC-FSTD and CDD-SM.

In addition, the UE can accurately estimate the interference signal transmission scheme, thereby improving the interference cancellation performance and improving the packet error performance.

1 is an illustration of a system in which a terminal receives signals from a serving cell and an interfering cell;
2 is an illustration of an interfering signal transmitted in an interfering cell;
Figure 3 is an exemplary pattern for two CSI-RS ports in an LTE system;
4 is an illustration of a pattern for four CSI-RS ports in an LTE system;
5 is another example of a pattern for two CSI-RS ports in an LTE system;
6 is another example of a pattern for four CSI-RS ports in an LTE system;
7 is a diagram illustrating operation of a base station and a terminal in a wireless communication system using CSI-RS of a pattern according to the present disclosure;
8 is an illustration of a pattern for four CSI-IM ports in an LTE system according to the present disclosure;
9 is a diagram illustrating operation of a base station and a terminal in a wireless communication system using a CSI-RS and an interfering signal transmission type reference signal of a pattern according to the present disclosure;
10 is an illustration of a pattern for four TM-IM ports in an LTE system according to the present disclosure;
11 is a diagram illustrating operation of a base station and a terminal in a wireless communication system using CSI-RS and channel state information-interfering signal transmission type reference signals of a pattern according to the present disclosure;
12 is an illustration of a pattern for four CSI-TM-IM ports in an LTE system according to the present disclosure;
13 is a diagram illustrating a method for a base station according to the present disclosure to transmit information for reference signal identification and CSI process information to a terminal;
14 is a diagram illustrating a configuration of a base station apparatus according to the present disclosure;
15 is a diagram illustrating the configuration of a terminal apparatus according to the present disclosure.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description of the present disclosure, a detailed description of known functions and configurations incorporated herein will be omitted when it may obscure the subject matter of the present disclosure. The terms used herein are defined in consideration of the functions of the present disclosure, which may vary depending on the user, the intention or custom of the operator, and the like. Therefore, the definition should be based on the contents throughout this specification.

Prior to the detailed description of the present disclosure, an example of an interpretable meaning is provided for some terms used herein. However, it should be noted that the present invention is not limited to the interpretation given below.

A base station is a base for communicating with a terminal, and may be referred to as a BS, a NodeB (NB), an eNode B (eNB), an AP (Access Point), or the like.

A user equipment may be referred to as a UE, a mobile station (MS), a mobile equipment (ME), a device, a terminal, or the like as a subject communicating with a base station.

In this disclosure, newly defined reference signals such as TM-IM and CSI-TM-IM will be described as well as reference signals used in LTE systems such as CSI-RS, CRS, CSI-IM and DM-RS.

A CRS (cell-specific reference signal) is a reference signal transmitted from a base station, and the terminal can use the CRS to estimate a channel (H) for data reception. The CRS has cell specific characteristics and can be transmitted in all downlink subframes and all frequency resource blocks.

A channel state information reference signal (CSI-RS) is a reference signal transmitted from a base station, and the terminal can use the CSI-RS as a measure of CSI of a serving cell. The CSI-RS is not transmitted in all downlink subframes, and is relatively sparse than the CRS, resulting in relatively little overhead.

A demodulation reference signal (DM-RS) is a reference signal transmitted from a base station. The terminal can use the DM-RS for physical downlink shared channel (PDSCH) channel estimation for the user equipment. The DM-RS has a UE-specific characteristic and can therefore only be transmitted in a resource block allocated for the PDSCH of the UE.

A CSI-IM (channel state information interference measurement) is a reference signal transmitted from a base station, and a UE can use the CSI-IM to measure an interference signal to measure channel state information. The CSI-IM can be transmitted in the same pattern as the CSI-RS. The base station can transmit both CSI-IM and CSI-RS and can transmit CSI-RS without transmission power, that is, zero-power CSI-RS in order to improve the performance of measuring the channel state information of the interference cell.

First, a method of defining a CSI-RS pattern considering a transmission scheme of a base station (for example, a transmission diversity transmission scheme using multiple antennas) will be described.

Figure 1 is an illustration of a system in which a terminal receives signals from a serving cell and an interfering cell.

The terminal 120 receives interfering signals 124 from the interfering base station 110 (i.e., the base station of the interfering cell) as well as the desired signal 122 from the serving base station 100 ).

2 is an exemplary diagram of an interference signal transmitted in an interference cell.

2, in the LTE system, not only a physical downlink shared channel (PDSCH) 200 as a data channel on a resource grid having a frequency and a time axis, The CRS 202, 204 may also be transmitted.

When transmitting data through the PDSCH 200, the BS can use various transmission schemes according to the channel environment with the MS. In particular, a base station based on multiple-input multiple-out (MIMO) using multiple antennas may use a transmit diversity technique and a spatial multiplexing (SM) technique. For example, in an LTE system using two transmit antennas, Space Frequency Block Codes (SFBC) or Cyclic Delay Diversity (CDD) based spatial multiplexing (SM) techniques (i.e., CDD -SM) can be used. The techniques, such as SFBC or CDD-SM, may be performed through two subcarriers (210) that are neighboring (or contiguous) (i.e., continuous on the frequency axis), as shown in the example given in FIG. .

Equation (1) represents a signal transmitted from antenna ports 0 and 1 through two neighboring carriers 210 (for example, a resource region defined by carriers 0 and 1) in the SFBC transmission scheme. According to Equation (1), signals x ₀ and -x ₁ ^* are transmitted to antenna ports 0 and 1 at carrier 0, and signals x ₁ and x ₀ ^* are transmitted at antenna port 0 and 1, respectively, .

Equations (2) and (3) represent signals transmitted through two neighboring carriers 0 and 1 in the CDD-SM transmission scheme, respectively.

Equation (2) illustrates a CDD-SM transmission scheme transmitted from carrier 0 to antenna ports 0 and 1, and Equation (3) illustrates a CDD-SM transmission scheme transmitted from carrier 1 to antenna ports 0 and 1. (X ₀ + x ₁ ) and 1/2 (x ₀ -x ₁ ) are transmitted to antenna ports 0 and 1 on carrier 0 and signals 1/2 x ₂ + x ₃ ) and 1/2 (-x ₂ + x ₃ ).

Equation (4) represents signals when carriers 0, 1, 2, 3 and four transmit antenna ports 0, 1, 2, 3 are used in the transmit diversity technique.

In LTE systems using four transmit antenna ports, more extended transmit diversity techniques and spatial multiplexing techniques are used. Examples of transmit diversity techniques are SFBC and FSTD (Frequency) using four antenna ports (0,1,2,3) and four neighboring carriers (e.g., carriers 0,1,2,3) -Switched Transmit Diversity) can be used as a transmission diversity technique.

As shown in Equations (1) to (4), the transmission scheme using multiple antennas transmits signals through neighboring carriers. Therefore, in order to accurately measure the channel state information of the received signal and to estimate the transmission scheme information, it is required to estimate together signals received from neighboring (consecutive) carriers on the frequency axis.

3 is an illustration of a CSI-RS pattern for two CSI-RS ports in an LTE system.

3, in the resource grid for one RB defined by 14 symbols on the time axis and 12 subcarriers on the frequency axis, CRS 0 (300) for CRS port 0 and CRS 1 (302 ), As well as a CSI-RS symbol 310 for two CSI-RS ports.

4 is an exemplary diagram of a CSI-RS pattern for four CSI-RS ports in an LTE system.

In FIG. 4, in the resource grid for one RB, CSI-RS symbols 410 and 412 for four CSI-RS ports as well as CRS 0 400 and CRS 1 402 are transmitted.

Referring to CSI-RS patterns (i.e., CSI-RS symbol allocation patterns) 310, 410, and 412 illustrated in FIGS. 3 and 4, a resource grid ) Span in the direction of the time axis in a single subcarrier. That is, the CSI-RSs 310, 410, and 412 in FIGS. 3 and 4 are transmitted on two consecutive (consecutive) symbols on a time axis in one subcarrier. The CSI-RS patterns of FIGS. 3 and 4 are contrary to the feature that the transmission signals are spanned (or contiguous) on the frequency axis at the same time (that is, the same symbol) in the transmission scheme using transmission diversity .

Accordingly, this disclosure proposes a method of maximizing the channel state information measurement performance and transmission scheme information estimation performance of a signal by defining a pattern of CSI-RS in consideration of a transmission method of a transmitter. Specifically, the present disclosure proposes a scheme for transmitting two or more CSI-RS symbols that are related to each other through two or more consecutive subcarriers on the frequency axis. 5 and 6 illustrate a CSI-RS pattern designed in consideration of a transmission scheme in an LTE system.

5 is another example of a CSI-RS pattern for two CSI-RS ports in an LTE system.

In FIG. 5, in the resource grid for one RB defined by 14 symbols on the time axis and 12 subcarriers on the frequency axis, two CSI-RS ports as well as CRS 0 500 and CRS 1 502, The CSI-RS symbol 510 is transmitted.

6 is another example of a CSI-RS pattern for four CSI-RS ports in an LTE system.

In FIG. 6, in the resource grid for one RB, CSI-RS symbols 610 and 612 for four CSI-RS ports as well as CRS 0 600 and CRS 1 602 are transmitted.

Referring to the CSI-RS patterns 510, 610 and 612 illustrated in FIGS. 5 and 6, the CSI-RS symbols are spread in the direction of the frequency axis from the same time resource in a resource grid defined by frequency and time You can see the span. That is, the CSI-RSs 510, 610, and 612 in FIGS. 5 and 6 are transmitted through two subcarriers neighboring (consecutive) on a frequency axis from one time resource (i.e., symbol). The CSI-RS patterns of FIGS. 6 and 6 show that two mutually related CSI-RS symbols (for example, symbols transmitted through adjacent antenna ports) in the transmission scheme using transmission diversity are transmitted at the same time Symbols) continuously arranged on the frequency axis. Therefore, as shown in FIGS. 5 and 6, the CSI-RS pattern defined in consideration of the transmission scheme of the transmitter can maximize the channel state information measurement performance and the transmission scheme information estimation performance of the signal.

The base station according to the present disclosure transmits the CSI-RS using the pattern illustrated in FIG. 5 or 6, and the terminal measures channel state information using the CSI-RS and feedbacks the channel state information to the base station .

7 is a diagram illustrating operation of a base station and a terminal in a wireless communication system using the CSI-RS of the pattern according to the present disclosure.

The procedure of FIG. 7 can be divided into two parts: a CSI feedback portion 710 and a data transfer portion 720. The terminal 702 feeds back channel state information using the reference signal transmitted from the base station 700, and the base station 700 can transmit data using the channel state information in operation 720. The operation of FIG. 7 will be described in more detail as follows.

The BS 700 transmits a pilot signal (i.e., a reference signal) used for channel state measurement of the MS 702 (712). The reference signal may be, for example, CSI-RS or CSI-IM.

At this time, the CSI-RS may have a CSI-RS pattern as illustrated in FIG. 5 or FIG. For example, the BS 700 is transmitting in a transmission diversity transmission scheme using two or more antenna ports, and two symbols among CSI-RS symbols transmitted through two or more CSI-RS ports are transmitted at the same time May be transmitted on two consecutive subcarriers in the resource. Likewise, CSI-IM can also be transmitted in the same pattern as the CSI-RS. The transmission diversity transmission scheme adopted by the BS 700 may be SFBC, SFBC-FSTD or CDD-SM. In particular, since the SFBC scheme is applied to the transmission mode 2 (TM 2) transmission scheme in the LTE system, the benefit of applying the CSI-RS pattern according to the present disclosure may arise.

8 is an illustration of a CSI-IM pattern for four CSI-IM ports in an LTE system according to the present disclosure;

8, in the resource grid for one RB defined by 14 symbols on the time axis and 12 subcarriers on the frequency axis, four CSI-IM ports as well as CRS 0 (800) and CRS 1 (802) The CSI-IM symbols 810 and 812 to be used are transmitted. Referring to the patterns 810 and 812 of the CSI-IM illustrated in FIG. 8, it can be seen that the CSI-IM symbols are spread in the direction of the frequency axis from the same time resource in the resource grid defined by frequency and time. That is, the CSI-IM signal can also be transmitted in the same pattern as the CSI-RS. Optionally, the neighboring cell's base station may transmit a zero-power CSI-RS from the resource for the CSI-IM signaling.

The UE 702 may measure channel state information of a serving cell (i.e., a serving BS) using a CSI-RS transmitted from the BS 700 in operation 714.

The UE 702 may measure channel state information of an interference cell (i.e., an interference base station) using the CSI-IM transmitted from the BS 700 (716).

The UE 702 may generate channel state information (of a serving cell) as a result of the measurement and may feed back to the base station 700 (718). The channel state information fed back to the BS 700 includes a channel quality indicator (CQI), a rank indicator (RI), and a precoding matrix indicator (PMI) May be included.

The BS 700 determines a transmission mode using the channel state information, and transmits the CRS to the MS 702 through the PDSCH (722). Taking the case of the LTE system as an example, the transmission modes in which the CRS is used for channel estimation of the terminal may correspond to TM 1 to TM 6.

The terminal 702 estimates a data transmission channel using the CRS, and receives the data using the estimated channel (724). Herein, the terminal estimates the channel by means of estimating the channel function H of the transport channel. For example, the received signal y can be expressed as y = Hx + n, where H is the channel function, x is the transmit signal, and n is the noise (including the interference signal).

Meanwhile, a next generation terminal (e.g., an LTE-A enabled terminal) may receive data by removing the interference signal from the received signal to reduce packet errors of the desired signal. In order to remove the interference signal, the terminal can use not only the channel information of the interference signal but also the transmission scheme information. 9 and 11 below show examples of a method of implementing an operation of estimating transmission scheme information of an interference signal in order to cancel an interference signal.

9 is a diagram illustrating operations of a base station and a terminal in a wireless communication system using a CSI-RS and an interference signal transmission method reference signal of the pattern according to the present disclosure.

The present disclosure proposes a new reference signal (hereinafter referred to as 'TM-IM') used for estimation of interfering signal transmission scheme information. The new reference signal TM-IM is a reference signal that helps blind detect transmission scheme information for the cell providing the strongest interference. The TM-IM may be referred to as a channel state information-transmission mode (CSI-TM) or a channel state information-transmission mode-interference measurement (CSI-TM-IM) The terminal 902 can estimate the transmission scheme information of the interference signal using the TM-IM transmitted from the base station 900 and remove the interference signal from the reception signal using the transmission scheme information of the estimated interference signal So that the packet error can be further reduced at the time of data reception.

The procedure of FIG. 9 can be divided into two parts: a CSI feedback part 910 and a data transfer part 930. The UE 902 feeds back channel state information using a reference signal transmitted from the Node B 900 in step 910 and the Node B 900 can transmit downlink data in step 930 using the channel state information. . The operation of FIG. 9 will be described in more detail as follows.

The base station 900 transmits a pilot signal (i.e., a reference signal) used for channel state measurement of the UE 902 (912). The reference signal may be, for example, CSI-RS or CSI-IM.

At this time, the CSI-RS may have a CSI-RS pattern as illustrated in FIG. 5 or FIG. For example, the BS 900 is transmitting in a transmission diversity transmission scheme using two or more CSI-RS ports, and transmits two symbols CSI-RS among the CSI-RS symbols transmitted through the two or more CSI- May be transmitted on two consecutive subcarriers in the same time resource. Likewise, CSI-IM can also be transmitted in the same pattern as the CSI-RS. For example, the transmission diversity transmission scheme adopted by the BS 900 may be SFBC, SFBC-FSTD, or CDD-SM.

The UE 902 may measure channel state information of a serving cell (i.e., a serving BS) using CSI-RS transmitted from the BS 900 in operation 914.

The UE 902 may measure channel state information of an interference cell (i.e., an interference base station) using CSI-IM transmitted from the BS 900 (916).

Alternatively, the UE 902 may estimate the transmission scheme information of the interfering cell based on the CSI-IM. Since the CSI-IM is transmitted through a pattern according to the transmission scheme of the BS, the MS 902 has a high possibility of estimating the transmission scheme information of the interference signal through the CSI-IM. The transmission scheme information may include, for example, a transmission mode (TM), a PMI, an RI, an MCS indicating a modulation scheme and a modulation level.

The UE 902 may generate channel state information (of a serving cell) as a result of the measurement and may feed back to the base station 900 (920). The channel state information fed back to the base station 900 may include at least one of CQI, PMI, and RI.

The BS 900 determines a transmission mode using the channel state information and transmits CRS and TM-IM (932) while transmitting data to the MS 902 through a PDSCH. Likewise, TM-IM can also be transmitted in the same pattern as the CSI-RS.

10 is an exemplary pattern of a TM-IM for four TM-IM ports in an LTE system according to the present disclosure;

10, in the resource grid for one RB defined by 14 symbols on the time axis and 12 subcarriers on the frequency axis, four TM-IM ports as well as CRS 0 (1000) and CRS 1 (1002) The TM-IM symbols 1010 and 1012 are transmitted. Referring to the patterns 1010 and 1012 of the TM-IM illustrated in FIG. 10, it can be seen that the TM-IM symbols are spread in the direction of the frequency axis from the same time resource in the resource grid defined by frequency and time (span) have. That is, the TM-IM signal can also be transmitted in the same pattern as the CSI-RS. Alternatively, a neighboring cell's base station may transmit a zero-power CSI-RS in the resource for the TM-IM signal transmission.

The terminal 902 estimates a data transmission channel using the CRS, and receives the data using the estimated channel (934). Herein, the terminal 902 estimates the channel by means of estimating the channel function H of the transport channel. At this time, the terminal 902 estimates the transmission scheme information of the interference signal using the TM-IM, removes the interference signal from the reception signal using the transmission scheme information of the interference signal, and receives the data. Examples of the transmission scheme information of the interference signal include an interference signal parameter such as TM (transmission mode), RI, PMI, or MCS.

11 is a diagram illustrating the operation of a base station and a terminal in a wireless communication system using CSI-RS and channel state information-interfering signal transmission method reference signals of a pattern according to the present disclosure.

The present disclosure proposes a new reference signal (hereinafter referred to as 'CSI-TM-IM') used for channel state information estimation and interference signal transmission scheme information estimation. The new reference signal CSI-TM-IM (Channel State Information-Transmission Mode-Interference Measurement) helps to blind detect transmission scheme information for the cell giving the strongest interference, Reference signal. The CSI-TM-IM may be referred to as a CSI-RSTM (channel state information-reference signal transmission mode) or the like. The terminal 1102 can estimate the transmission scheme information of the interference signal and measure the channel state information using the CSI-TM-IM transmitted from the base station 1100. The UE 1102 can further reduce a packet error in data reception by removing an interference signal from a reception signal using the transmission scheme information of the interference signal, and by feedbacking the measured channel state information, Data may be received according to a transmission scheme based on an accurate channel state.

The procedure of FIG. 11 can be divided into two parts: a CSI feedback portion 1110 and a data transmission portion 1130. The UE 1102 feeds back channel state information using a reference signal transmitted from the Node B 1100 and the Node B 1100 can transmit downlink data using the channel state information 1130, . The operation of FIG. 11 will be described in more detail as follows.

The base station 1100 transmits a pilot signal (i.e., a reference signal) used for channel state measurement of the UE 1102 (1112). The reference signal may be, for example, CSI-RS or CSI-IM.

At this time, the CSI-RS may have a CSI-RS pattern as illustrated in FIG. 5 or FIG. For example, the BS 1100 is transmitting a CSI-RS in a transmission diversity transmission scheme using two or more CSI-RS ports, and transmits CSI-RS symbols transmitted through the two or more CSI- Two of the symbols may be transmitted on two consecutive subcarriers in the same time resource. Likewise, CSI-IM can also be transmitted in the same pattern as the CSI-RS. The transmission diversity transmission scheme adopted by the BS 1100 may be SFBC, SFBC-FSTD or CDD-SM.

The UE 1102 can measure channel state information of a serving cell (i.e., a serving BS) using the CSI-RS transmitted from the BS 1100 (1114).

The UE 1102 may measure the channel state information of the interference cell (i.e., the interference base station) using the CSI-IM transmitted from the BS 1100 (1116).

Alternatively, the UE 1102 may estimate the transmission scheme information of the interference cell based on the CSI-IM. Since the CSI-IM is transmitted through a pattern according to the transmission scheme of the BS, the MS 1102 has a high possibility of estimating the transmission scheme information of the interference signal through the CSI-IM. The transmission scheme information may include, for example, a transmission mode (TM), a PMI, an RI, an MCS indicating a modulation scheme and a modulation level.

The UE 1102 may generate channel state information (of a serving cell) as a result of the measurement and may feed back to the BS 1100 (1120). The channel state information fed back to the base station 1100 may include at least one of CQI, PMI, and RI.

The BS 1100 determines a transmission mode using the channel status information and transmits CRS and CSI-TM-IM while transmitting data to the UE 1102 through a PDSCH (1132). Likewise, CSI-TM-IM can also be transmitted in the same pattern as CSI-RS.

Figure 12 is an exemplary pattern view of CSI-TM-IM using four CSI-TM-IM ports in an LTE system according to the present disclosure.

12, in the resource grid for one RB defined by 14 symbols on the time axis and 12 subcarriers on the frequency axis, four CSI-TM-IMs (not shown), as well as CRS 0 1200 and CRS 1 1202, CSI-TM-IM symbols 1210 and 1212 for the port are transmitted. Referring to the patterns 1210 and 1212 of the CSI-TM-IM illustrated in FIG. 12, it can be seen that the CSI-TM-IM symbols are spread in the direction of the frequency axis from the same time resource in the resource grid defined by frequency and time . That is, the CSI-TM-IM signal can also be transmitted in the same pattern as the CSI-RS. Alternatively, the neighboring cell's base station may transmit a zero-power CSI-RS from the resource for CSI-TM-IM signaling.

The UE 1102 estimates a data transmission channel using the CRS, and receives the data using the estimated channel (1134). Herein, the terminal 1102 estimates the channel by means of estimating the channel function H of the transport channel. At this time, the UE 1102 may estimate the transmission scheme information of the interference signal using the CSI-TM-IM and may measure and re-feedback channel state information. The UE 1102 can remove the interference signal from the received signal using the transmission scheme information of the interference signal and receive the data. Examples of the transmission scheme information of the interference signal include an interference signal parameter such as TM (transmission mode), RI, PMI, or MCS.

13 is a diagram illustrating a method by which a base station according to the present disclosure transmits information for identifying a reference signal and CSI process information to the terminal.

7 to 12, the base station 1300 may transmit the reference signal identification information or the information of the CSI process to the UE 1302 before the transmission of the reference signal and the feedback operation of the channel status information (1310).

The reference signal identification information includes at least one of CSI-RS, CSI-IM, TM-IM, CSI-TM-IM and Zero-Power CSI-RS, which are transmitted according to the pattern according to the present disclosure. To the terminal. The information identifying the reference signal may be transmitted through signaling of a radio resource control (RRC) layer or through downlink control information (DCI) of a physical layer.

The CSI process includes a CSI-RS, a CSI-IM, a TM-IM, a CSI-TM-IM, and a Zero-Power CSI-RS, which are transmitted according to the pattern according to the present disclosure. And information indicating a position of a selected at least one reference signal and a resource to be used for transmission of the reference signal. Preferably, the CSI process may include one to three information signals of about four or more. The CSI process information may be transmitted through the signaling of the RRC layer or through the DCI of the physical layer.

14 is a diagram illustrating a configuration of a base station apparatus according to the present disclosure.

The base station apparatus 1400 includes a transceiver 1410 capable of communicating signals with a terminal; And a controller 1420 for controlling the transceiver 1410. It is needless to say that the transceiver 1410 and the controller 1420 may be implemented as a single device.

The controller 1420 is a component that implements the reference signal transmission and data transmission method performed in the base station described in the present disclosure. That is, it can be understood that all the operations of the above-described base station are performed by the control unit 1420. [

15 is a diagram illustrating the configuration of a terminal apparatus according to the present disclosure.

The terminal device 1500 includes a transceiver 1510 capable of communicating a signal with a base station or another terminal; And a control unit 1520 for controlling the transceiver unit 1510. The transceiver 1510 and the controller 1520 may be implemented as a single device.

The controller 1520 is a component that implements the transmission / reception method of the terminal described in the present disclosure. That is, it can be understood that all operations of the terminal described above are performed by the control unit 1520. [

It should be noted that the configuration diagram, the resource grid diagram, the method diagram, and the apparatus diagram of the system exemplified in Figs. 1 to 15 are not intended to limit the scope of the present disclosure. That is, not all of the descriptions, resource grid arrangements, components, or operational steps described in FIGS. 1 through 15 above should be construed as essential elements for the practice of the present disclosure, The present invention can be implemented within a range that does not impair the essence of the present invention.

The above-described operations can be realized by providing a memory device storing the program code in an entity, a function, a base station, or any component in the terminal device of the communication system. That is, the control unit of the entity, the function, the base station, or the terminal device can execute the above-described operations by reading and executing the program code stored in the memory device by the processor or the CPU (Central Processing Unit).

The various components, modules, and the like of an entity, a function, a base station, or a terminal device described herein may be implemented in a hardware circuit, for example, a complementary metal oxide semiconductor And a hardware circuit, such as a combination of firmware and software and / or software embedded in hardware and firmware and / or machine-readable media. In one example, the various electrical structures and methods may be implemented using electrical circuits such as transistors, logic gates, and custom semiconductors.

While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. Therefore, the scope of the present disclosure should not be limited to the embodiments described, but should be determined by the scope of the appended claims, as well as the appended claims.

Claims (24)

A communication method of a user equipment (UE) in a cellular communication system,
Receiving a CSI-RS (channel state information reference signal) transmitted according to a pattern on a resource grid determined based on a transmission scheme of a base station;
Measuring a transmission channel state with the base station using the CSI-RS and generating and feeding back channel state information of the terminal;
Receiving a downlink signal comprising data and a cell-specific reference signal (CRS) from the base station; And
Estimating a transport channel with the base station using the CRS, and obtaining the data using the estimated channel. The method according to claim 1,
The UE operates in a transmit diversity transmission scheme,
Wherein the pattern is a pattern in which two associated CSI-RS symbols are transmitted on two consecutive subcarriers on the frequency axis of the resource grid. 3. The method of claim 2,
Wherein the two associated CSI-RS symbols are two CSI-RS symbols transmitted through two CSI-RS ports used in the transmission scheme. The method according to claim 1,
And receiving a CSI-interference measurement (CSI-IM) transmitted using the pattern. The method according to claim 1,
Receiving a first reference signal transmitted using the pattern and used for interference signal transmission scheme information estimation; And
Estimating transmission scheme information of the interference signal using the first reference signal and removing the interference signal from the downlink signal using the estimated transmission scheme information of the interference signal. The method according to claim 1,
Receiving a second reference signal transmitted using the pattern, the second reference signal being used for channel state information measurement and interference signal transmission scheme information estimation; And
Estimating transmission scheme information of the interference signal using the second reference signal and removing the interference signal from the downlink signal using the estimated transmission scheme information of the interference signal; And
And generating and re-feeding channel state information of the UE using the estimated transmission scheme information of the interference signal. The method according to claim 1,
The CSI-RS is transmitted in a transmission scheme based on any one of Space Frequency Block Codes (SFBC), Frequency-Switched Transport Diversity (SFBC-FSTD) and cyclic delay diversity-spatial multiplexing (CDD-SD) Way. The method according to claim 1,
Wherein the channel state information includes at least one of a channel quality indicator (CQI) indicating a modulation and coding scheme, a rank indicator (RI), and a precoding matrix indicator (PMI). 6. The method of claim 5,
The transmission scheme information of the interference signal includes at least one of a transmission mode, a precoding matrix indicator (PMI), a rank indicator, a modulation and coding scheme (MCS) indicating a modulation scheme-modulation level of the interference signal ≪ / RTI > The method of claim 1, further comprising: prior to receiving the channel state information reference signal (CSI-RS)
A CSI-RS, a zero-power CSI-RS, a CSI-IM, a first reference signal used for interference signal transmission scheme information estimation, and a channel state information measurement and an interference signal transmission scheme information, (RRC) layer signaling or downlink control information (DCI) to indicate at least one of a first reference signal and a second reference signal. The method according to claim 1,
Prior to receiving the CSI-RS (channel state information reference signal)
A CSI-RS, a zero-power CSI-RS, a CSI-IM, a first reference signal used for interference signal transmission scheme information estimation, and a channel state information measurement and an interference signal transmission scheme information, ≪ / RTI > further comprising receiving information indicating a CSI process for at least one of a first reference signal and a second reference signal. A method of communicating a base station in a cellular communication system,
Transmitting a CSI-RS (channel state information reference signal) to a mobile station according to a pattern on a resource grid determined based on a transmission scheme of the base station;
Receiving channel state information of the UE measured using the CSI-RS; And
Data and a downlink signal comprising a cell-specific reference signal (CRS). 13. The method of claim 12,
The base station operates in a transmit diversity transmission scheme,
Wherein the pattern is a pattern in which two associated CSI-RS symbols are transmitted on two consecutive subcarriers on the frequency axis of the resource grid. 14. The method of claim 13,
Wherein the two associated CSI-RS symbols are two CSI-RS symbols transmitted through two CSI-RS ports used in the transmission scheme. 13. The method of claim 12,
And transmitting the CSI-interference measurement (CSI-IM) according to the pattern. 13. The method of claim 12,
And transmitting a first reference signal used for interference signal transmission scheme information estimation according to the pattern. 13. The method of claim 12,
Transmitting a second reference signal used for channel state information measurement and interference signal transmission scheme information estimation according to the pattern; And
And receiving channel state information of the terminal generated based on transmission scheme information of the interference signal estimated using the second reference signal. 13. The method of claim 12,
The CSI-RS is transmitted in a transmission scheme based on any one of Space Frequency Block Codes (SFBC), Frequency-Switched Transport Diversity (SFBC-FSTD) and cyclic delay diversity-spatial multiplexing (CDD-SD) Way. 13. The method of claim 12,
Wherein the channel state information includes at least one of a channel quality indicator (CQI) indicating a modulation and coding scheme, a rank indicator (RI), and a precoding matrix indicator (PMI). 17. The method of claim 16,
The interference signal transmission scheme information includes at least one of a transmission mode (TM), a precoding matrix indicator (PMI), a rank indicator (RI), and a modulation and coding scheme (MCS) indicating a modulation scheme-modulation level ≪ / RTI > 13. The method of claim 12, further comprising: prior to transmitting the CSI-RS (channel state information reference signal)
A CSI-RS, a zero-power CSI-RS, a CSI-IM, a first reference signal used for interference signal transmission scheme information estimation, and a channel state information measurement and an interference signal transmission scheme information, (RLC) layer signaling or downlink control information (DCI) to indicate at least one of a first reference signal and a second reference signal. 13. The method of claim 12,
Prior to receiving the CSI-RS (channel state information reference signal)
A CSI-RS, a zero-power CSI-RS, a CSI-IM, a first reference signal used for interference signal transmission scheme information estimation, and a channel state information measurement and an interference signal transmission scheme information, Further comprising transmitting information indicative of a CSI process for at least one of the first reference signal and the second reference signal via RRC layer signaling or downlink control information (DCI). A user equipment (UE) in a cellular communication system,
A channel state information reference signal (CSI-RS) transmitted according to a pattern on a resource grid determined based on a transmission scheme of a base station, measures a transmission channel state with the base station using the CSI-RS, And a downlink signal including a cell-specific reference signal (CRS) from the base station, estimating a transmission channel with the base station using the CRS, A control unit configured to acquire the data using a channel that has been channeled; And
And a transmission / reception unit for receiving the CSI-RS under the control of the control unit, feeding back the channel state information, and receiving the downlink signal. A base station communicating in a cellular communication system,
Transmits a channel state information reference signal (CSI-RS) according to a pattern on a resource grid determined based on a transmission scheme of the BS, and receives channel state information of the UE measured using the CSI-RS , A data and a cell-specific reference signal (CRS); And
And a transmission / reception unit for transmitting the CSI-RS under the control of the control unit, receiving the channel status information, and transmitting the downlink signal.

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