TWI687110B - Scheme for transmitting reference signal in wireless communication system - Google Patents

Abstract

Methods, systems, apparatuses, evolved NodeB (eNBs), User Equipment (UE), and chip sets for all of the same, in cellular communication systems are described.  One method for a UE includes receiving a Channel State Information Reference Signal (CSI-RS) transmitted by an eNB according to a pattern in a time-frequency resource grid determined based on the transmission scheme of the eNB, measuring the state of the transmission channel using the CSI-RS, generating channel state information based on the measuring, and transmitting the channel state information as feedback.  The UE receives a downlink signal including data and a Cell-specific Reference Signal (CRS) from the eNB and estimates the transmission channel using the CRS and then acquires the data using the estimated channel.

Description

Mechanism for transmitting reference signal in wireless communication system

The present invention relates to a mechanism for transmitting a reference signal in a wireless communication system, and more particularly to a method and device for transmitting a reference signal according to an interference signal in a cellular communication system.

In next-generation wireless communication systems (for example, Long Term Evolution-Advanced (LTE-A) systems), cell coverage is relatively small compared to the traditional cellular environment. When various cells, such as traditional cells and femtocells, operate in the same environment, a non-uniform cell distribution occurs.

User equipment (UE) can not only receive required signals (also called "demanded signals") from the serving cell, but also receive unwanted signals from another or "interfering" cell (Also known as "interfering signal"). In such an environment, inter-cell interference is the largest factor that increases packet error, and thus reduces the performance of the UE.

In the LTE wireless communication system, the evolved NodeB (evolved NodeB, eNB) transmits a reference signal (eg, Channel State Information-Reference Signal (CSI-RS)) before transmitting data to the UE to allow the UE to measure the channel quality of the serving cell. In addition, the eNB may use CSI interference measurement (Interference Measurement, IM) to allow the UE to measure channel quality in consideration of channels of neighboring cells.

The UE determines the channel quality indicator (CQI) using CSI-IM and transmits the feedback of the channel quality information to the eNB. The eNB transmits the data to the UE based on the feedback. At this time, the eNB may also transmit a cell-specific reference signal (CRS) for a specific cell on the orthogonal frequency division multiplex (OFDM) domain together with the data, so that When the UE receives the data, the UE can estimate the required channel (ie, the channel of the required signal).

In order for the next generation UE (eg, Long Term Evolution Advanced (LTE-A) UE) to remove the interference signal from the received signal most efficiently to reduce the packet error of the desired signal, the UE needs the transmission mechanism information of the interference signal and Channel information of the interference signal. Although CSI-IM can be used to estimate the transmission mechanism information of the interfering signal, this estimation is limited because CSI-IM reuses CSI-RS resource patterns that are not suitable for estimating the transmission mechanism. The CSI-RS pattern is defined as the location (or distribution) of resource elements of the CSI reference signal used for transmission.

Therefore, to solve the interference problem, a method, device, and system for accurately estimating the transmission mechanism of the interference signal received by the next-generation UE are required.

In order to overcome the limitations of CSI-IM, an aspect of the present invention provides a new CSI-RS pattern that first considers the transmission mechanism, and provides an estimate of the transmission mechanism information of the interference signal using the provided CSI-RS pattern The method of maximizing efficiency. Another aspect of the present invention provides a new RS for estimating transmission mechanism information of an interference signal for use by a next-generation UE to remove the interference signal.

According to another aspect of the present invention, the UE can determine accurate channel status information and increase system capacity accordingly. According to yet another aspect of the present invention, the UE can increase the SFBC-FSTD, SFBC-FSTD, or cyclic delay based on Space Frequency Block Code (SFBC) Diversity (Cyclic Delay Diversity, CDD) spatial multiplexing (CDD Spatial Multiplexing, CDD-SM) transmission mechanism estimation capability. In this aspect, the UE may enable false alarm detection errors and missed alarms caused by interference signals in the transmission mechanism including at least one of SFBC, SFBC-FSTD, and CDD-SM The detection error (miss alarm detection error) is minimized. According to yet another aspect of the present invention, the UE can improve interference removal capability by accurately estimating the transmission mechanism of the interference signal, and accordingly enhance its packet error estimation capability.

100: Servo eNB

110: Interfering eNB

120:UE

122: required signal

124: Interfering signal

200: Physical Downlink Shared Channel (PDSCH)

202: Reference signal of a specific cell (CRS#0 signal)

204: Reference signal of a specific cell (CRS#1 signal)

210: subcarrier

300: CRS#0 signal

302: CRS#1 signal

310: CSI-RS symbol

400: CRS#0 signal

402: CRS#1 signal

410: CSI-RS symbol

412: CSI-RS symbol

500: CRS#0 signal

502: CRS#1 signal

510: CSI-RS symbol

600: CRS#0 signal

602: CRS#1 signal

610: CSI-RS symbol

612: CSI-RS symbol

700: eNB

702:UE

710: CSI feedback part

720: Data transmission part

712~718, 722~724: steps

800: CRS#0 signal

802: CRS#1 signal

810: CSI-RS symbol

812: CSI-RS symbol

900: eNB

902:UE

910: CSI feedback part

930: Data transmission part

912~920, 932~934: steps

1000: CRS#0 signal

1002: CRS#1 signal

1010: TM-IM symbol

1012: TM-IM symbol

1100: eNB

1102: UE

1110: CSI feedback section

1130: Data transmission part

1112~1120, 1132~1136: steps

1200: CRS#0 signal

1202: CRS#1 signal

1210: CSI-TM-IM symbol

1212: CSI-TM-IM symbol

1300: eNB

1302: UE

1310: Step

1400: eNB device

1410: Transceiver

1420: Controller

1500: UE device

1510: Transceiver

1520: Controller

The above and other aspects, features, and advantages of the present invention will become more apparent by reading the following detailed description in conjunction with the drawings. In the drawings:

FIG. 1 illustrates an example of a system in which a UE receives signals from a serving cell and an interfering cell.

Figure 2 illustrates an example of an interference signal transmitted from an interfering cell.

FIG. 3 illustrates an example of a pattern using two CSI-RS ports in the LTE system.

FIG. 4 illustrates an example of a pattern using four CSI-RS ports in the LTE system.

FIG. 5 illustrates an example of a pattern using two CSI-RS ports in the LTE system.

FIG. 6 illustrates an example of a pattern using four CSI-RS ports in the LTE system.

7 illustrates an example of operations of eNB and UE in a wireless communication system using CSI-RS of resource patterns according to the present invention.

8 illustrates an example of a pattern of four CSI-IM ports in an LTE system according to the present invention.

9 illustrates an example of operation of eNB and UE and interference signal transmission mechanism reference signal in a wireless communication system using CSI-RS of resource patterns according to the present invention.

FIG. 10 illustrates an example of a pattern of four TM-IM ports in an LTE system according to the present invention.

11 illustrates an example of operation of eNB and UE and channel state information-interference signal transmission mechanism reference signal in a wireless communication system using CSI-RS of resource patterns according to the present invention.

12 illustrates an example of a pattern of four CSI-TM-IM ports in an LTE system according to the present invention.

13 illustrates an example of a method by which an eNB transmits information for identifying reference signals and CSI process information to a UE according to the present invention.

14 is a block diagram of an eNB device according to the present invention.

15 is a block diagram of a UE device according to the present invention.

Hereinafter, embodiments of the present invention will be explained in detail with reference to the drawings. In the following description of the present invention, when detailed descriptions of known configurations or functions incorporated herein are unnecessary for those of ordinary skill in the art and/or such detailed descriptions may make the subject matter of the present invention When it becomes unclear, a detailed description of the known configuration or function will be omitted. The terms described herein are used and/or defined in consideration of the function of the present invention, but the terms and the specific implementation of the terms may be changed according to the intention or agreement of the user or operator. Therefore, the definition of terms should be determined based on the contents in the entire specification and the knowledge of ordinary knowledgeable people in the technology, and should not be interpreted as limiting the overall disclosure content or scope of the accompanying patent application in any way.

In the detailed description of the present invention, examples of interpretable meanings of certain terms used in the present invention are provided; however, these terms are not limited to examples of understandable meanings provided below.

A base station is a main body that communicates with a user equipment (UE), and may be called BS, Node B (NB), eNode B (eNB), access point (Access Point, AP), and so on.

The user equipment is the object of communication with the BS, and may be called a UE, a mobile station (MS), a mobile equipment (ME), a device, a terminal, and so on.

In the present invention, reference signals used in the LTE system (such as CSI-RS, CRS, CSI-IM, and demodulation-reference signal (DM-RS)) and newly defined reference signals (such as "Transmission Mode-Interference Measurement (TM-IM)" and "Channel State Information-Transmission Mode-Interference Measurement (CSI-TM-IM)" signals ).

The cell-specific reference signal (CRS) refers to the reference signal transmitted from the eNB and used by the UE to estimate the data reception channel (H). The CRS has cell-specific characteristics and is transmitted in all downlink subframes and all frequency resource blocks.

Channel status information-reference signal (CSI-RS) refers to the reference signal transmitted from the eNB and used by the UE to measure the channel status information (CSI) of the serving cell. The CSI-RS is not transmitted in all downlink subframes, but is transmitted sparsely to generate a relatively small overhead compared to CRS.

The demodulated variable reference signal (DM-RS) refers to a reference signal transmitted from the eNB and used by the UE to estimate a physical downlink shared channel (Physical Downlink Shared Channel, PDSCH). The DM-RS has UE-specific characteristics and is accordingly transmitted in resource blocks allocated for the PDSCH of the UE.

Channel state information-interference measurement (CSI-IM) refers to a reference signal transmitted from an eNB and used by the UE to take into account interference signals when measuring channel state information. The CSI-IM uses the same pattern as the CSI-RS for transmission. eNB CSI-RS without transmission power (ie, zero-power CSI-RS) can be transmitted to improve the channel state information measurement performance of the interfering cell.

According to one aspect of the present invention, there is provided a method for user equipment (UE) in a cellular communication system, comprising: receiving a channel state information reference signal (CSI) transmitted according to a pattern in a time-frequency resource grid -RS), the pattern is determined by the evolved NodeB (eNB) based on the transmission mechanism; using the CSI-RS to measure the state of the transmission channel with the eNB; generating channel state information based on the measurement; Transmitting the channel state information as feedback to the eNB; receiving a reference signal (CRS) for a specific cell from the eNB; using the CRS to estimate the transmission channel; and using the estimated channel to obtain the Data transmitted on the transmission channel.

According to another aspect of the present invention, a method for an evolved NodeB (eNB) in a cellular communication system is provided, which includes: according to a pattern in a time-frequency resource grid, a channel state information reference signal (CSI-RS ) Transmission to the user equipment (UE), the pattern is determined based on the transmission mechanism of the eNB; receiving channel state information of the UE generated using the CSI-RS; and transmission including data and targeting a specific cell The reference signal (CRS) is the downlink signal.

According to yet another aspect of the present invention, a user equipment (UE) used in a cellular communication system includes a controller that receives a channel state information reference signal transmitted according to a pattern in a time-frequency resource grid (CSI-RS), the pattern is determined based on the evolved NodeB (eNB) transmission mechanism; using the CSI-RS measurement and the status of the eNB's transmission channel; generated based on the measurement Channel status information; transmitting the channel status information as feedback to the eNB; receiving a reference signal (CRS) for a specific cell from the eNB; estimating the transmission channel using the CRS; and using the estimated channel Acquiring data transmitted on the transmission channel; and a transceiver that receives the CSI-RS under the control of the controller, transmits the channel state information, and receives the CRS and the transmission channel.

According to yet another aspect of the present invention, there is provided an evolved NodeB (eNB) for use in a cellular communication system, including: a controller, according to a pattern in a time-frequency resource grid, channel state information reference signal (CSI- RS) transmission to user equipment (UE), the pattern is determined based on the transmission mechanism of the eNB, receiving channel state information of the UE generated by using the CSI-RS, and transmission including data and specific A downlink signal of a cell's reference signal (CRS); and a transceiver that transmits the CSI-RS under the control of the controller, receives the channel state information, and transmits the downlink signal.

According to yet another aspect of the present invention, a chip set for user equipment (UE) in a cellular communication system is provided to: receive a chip set transmitted according to a pattern in a time-frequency resource grid Channel status information reference signal (CSI-RS), the pattern is determined by the evolved NodeB (eNB) based on the transmission mechanism; using the CSI-RS to measure the status of the transmission channel with the eNB; based on the amount Generate channel state information by measuring; transmitting the channel state information as feedback to the eNB; receiving a reference signal (CRS) for a specific cell from the eNB; estimating the transmission channel using the CRS; and using the The estimation channel obtains the data transmitted on the transmission channel.

According to another aspect of the present invention, a chip set for an evolved NodeB (eNB) in a cellular communication system is provided for: according to a pattern in a time-frequency resource grid, a channel state information reference signal (CSI -RS) transmission to user equipment (UE), the pattern is determined based on the transmission mechanism of the eNB; receiving channel state information of the UE generated by using the CSI-RS; and transmission including data and The downlink signal of the cell-specific reference signal (CRS).

First, the mechanism for defining the CSI-RS resource pattern in consideration of the transmission mechanism of the eNB (for example, a transmission diversity transmission scheme using multiple antennas) is explained.

FIG. 1 illustrates an example of a system in which a UE receives signals from a serving cell and an interfering cell.

The UE 120 receives not only the required signal 122 from the eNB 100 (ie, the eNB of the serving cell), but also the interference signal 124 from the eNB 110 (ie, the eNB of the interfering cell).

Figure 2 illustrates an example of an interference signal transmitted from an interfering cell.

As shown in FIG. 2, in the LTE system, CRS 202 and 204 and the physical downlink shared channel (PDSCH) 200 corresponding to the data channel can be in a time-frequency resource grid (ie, resources with a frequency axis and a time axis) Grid).

When transmitting data via the PDSCH 200, the eNB can utilize various transmission mechanisms according to the channel environment with the UE. Specifically, multiple-input multiple-output (MIMO)-based eNBs that use multiple antennas can utilize transmission diversity technology and spatial multiplexing (SM) technology. For example, in an LTE system using two transmission antennas, transmission diversity technology based on spatial frequency block codes (SFBC) or SM technology based on cyclic delay diversity (CDD) (ie, CDD-SM) may be utilized. Technologies such as SFBC or CDD-SM are implemented by two adjacent (or adjacent) subcarriers 210 (ie, subcarriers that are continuous on the frequency axis) as shown in the example of FIG. 2.

在副載波0上分別傳輸至天線埠0及1，且信號x ₁及

在副載波1上分別傳輸至天線埠0及1。 Equation (1) represents the signal transmitted to the antenna ports 0 and 1 using the two adjacent carriers 210 (for example, the resource area defined by subcarriers 0 and 1) using the SFBC transmission mechanism. Based on equation (1), the signal x ₀ and

Transmit to sub-carrier 0 to antenna ports 0 and 1, respectively, and the signal x ₁ and

It is transmitted to antenna ports 0 and 1 on subcarrier 1 respectively.

Each of equations (2) and (3) represents a signal transmitted using two adjacent carriers 0 and 1 in the CDD-SM transmission mechanism.

Equation (2) shows an example of the CDD-SM transmission mechanism in which the signal is transmitted to the antenna ports 0 and 1 on carrier 0, and Equation (3) shows the CDD-SM in which the signal is transmitted to the antenna ports 0 and 1 on carrier 1 Examples of transmission mechanisms. Signals 1/2 ( x ₀ + x ₁ ) and 1/2 ( x ₀ - x ₁ ) are transmitted on carrier 0 to antenna ports 0 and 1, respectively, and signals 1/2 ( x ₂ + x ₃ ) and 1/ 2(- x ₂ + x ₃ ) is transmitted on carrier 1 to antenna ports 0 and 1.

The LTE system using four transmission antenna ports has expanded transmission diversity and spatial multiplexing. Transmission diversity techniques, for example, can use four antenna ports 0, 1, 2 and 3 and four adjacent carriers (for example, carriers 0, 1, 2 and 3) to combine SFBC and frequency switched transmission diversity (FSTD) .

For example, equations (4)(a) and (4)(b) represent the signals when carrier 0, 1, 2 and 3 and four transmission antenna ports 0, 1, 2 and 3 are used in the transmission diversity technique .

Equations (1) to (4) (b) represent signals in a transmission mechanism using multiple antennas to transmit signals via adjacent carriers. In order to accurately measure the channel status information and transmission mechanism information of the received signal, it is necessary to estimate the signal received through the adjacent (continuous) carrier on the frequency axis.

FIG. 3 illustrates an example of CSI-RS patterns of two CSI-RS ports in a time-frequency resource grid of a resource block (Resource Block, RB) composed of resource elements (RE) in an LTE system The resource element is defined by fourteen symbols on the time axis and twelve subcarriers on the frequency axis.

In FIG. 3, the CRS#0 signal 300 is used for CRS port 0, the CRS#1 signal 302 is used for CRS port 1, and the CSI-RS symbol 310 is used for two CSI-RS ports.

4 illustrates an example of CSI-RS patterns of four CSI-RS ports in a time-frequency resource grid of one RB in an LTE system.

In FIG. 4, CRS#0 signal 400, CRS#1 signal 402, and CSI-RS symbols 410 and 412 for four CSI-RS ports are shown.

Referring to the CSI-RS patterns 310, 410, and 412 shown in FIGS. 3 and 4, it can be noted that the CSI-RS symbols are spread in the time axis direction in the signal subcarriers of the time-frequency resource grid. That is, the CSI-RS 310, 410, and 412 of FIGS. 3 and 4 utilize two symbols that are adjacent (continuous) on the time axis in one subcarrier to transmit. The CSI-RS patterns of FIGS. 3 and 4 are opposite to the following characteristics in the transmission mechanism using transmission diversity: the transmitted signals are arranged to be spread (or continuous) on the frequency axis at the same time (ie, the same sign) .

Therefore, the present invention provides a method for maximizing the channel state information measurement performance and the transmission mechanism information estimation performance of a signal by considering the transmission mechanism of the transmitter to define the CSI-RS pattern. Specifically, the present invention provides a method of transmitting two or more CSI-RS symbols related to each other using two or more subcarriers that are continuous on the frequency axis. 5 and 6 illustrate the CSI-RS pattern designed in consideration of the transmission mechanism in the LTE system.

5 illustrates another example of the CSI-RS pattern of two CSI-RS ports in a time-frequency resource grid of one RB in the LTE system, the one RB is composed of fourteen symbols and frequencies on the time axis Twelve subcarriers on the axis are defined.

In FIG. 5, the CRS#0 signal 500, the CRS#1 signal 502, and the CSI-RS symbol 510 for the two CSI-RS ports are transmitted as shown.

FIG. 6 illustrates another example of CSI-RS patterns of four CSI-RS ports in a time-frequency resource grid of one RB in the LTE system.

In FIG. 6, the CRS#0 signal 600, the CRS#1 signal 602, and the CSI-RS symbols 610 and 612 for the four CSI-RS ports are transmitted as shown. The CSI-RS patterns 510, 610, and 612 shown in FIGS. 5 and 6 are spread in the frequency axis direction of the time-frequency resource grid but occupy the same time resource (ie, symbol). That is, the CSI-RS 510, 610, and 612 of FIGS. 5 and 6 utilize two adjacent (continuous) frequency subcarriers but only transmit in one time resource (ie, the same symbol).

The eNB according to the present invention can use the patterns shown in FIGS. 5 and 6 to transmit CSI-RS, and the UE can use the CSI-RS to measure channel state information and transmit feedback to the eNB. For the correspondence between the characteristics shown in FIG. 5 and FIG. 6, the CSI-RS pattern defined in consideration of the transmission mechanism of the transmitter can maximize the performance by improving channel state information measurement and transmission mechanism information estimation.

7 illustrates an example of operations of eNB and UE in a wireless communication system using patterned CSI-RS according to the present invention.

The process of FIG. 7 can be divided into two parts, namely a CSI feedback part 710 and a data transmission part 720. In the feedback part, the UE 702 provides feedback channel status information using the reference signal transmitted from the eNB 700 in step 712, and in the data transmission part 720, the eNB 700 uses the channel status information fed back by the UE in the first part 710 and Transfer data. The operation of FIG. 7 will be explained in more detail below.

In step 712, the eNB 700 transmits a pilot signal (ie, a reference signal) used by the UE 702 to measure the channel status. The reference signal may For example, CSI-RS or CSI-IM. More specifically, the UE 702 uses the CSI-RS transmitted by the serving eNB 700 to measure the channel status of the serving cell, and uses the CSI-IM transmitted by the serving eNB and/or other interfering eNBs to measure the interference cell's Channel status. In step 714, the UE 702 uses the CSI-RS received from the serving eNB 700 to measure the serving cell channel status. In step 716, the UE 702 uses the CSI-IM received from the serving eNB and/or other interfering eNB to measure the interfering cell channel status. In step 718, the UE 702 generates servo cell channel state information (CSI) based on the measurements in step 714 and step 716 and transmits the servo cell channel state information (CSI) to the servo eNB 700.

The CSI fed back to the eNB 700 in step 718 may include a channel quality indicator (CQI), an indicator indicating modulation and coding mechanism (MCS), a rank indicator (RI), and/or a precoding matrix indicator (Precoding Matrix Indicator, PMI).

Using the CSI received in step 718, the eNB 700 may determine the transmission mechanism of the UE 702. For example, in the LTE system, the CRS-based transmission mode may correspond to TM 1 to TM 6. In step 722, the eNB 700 transmits the CRS while transmitting the data to the UE 702 via the PDSCH.

In step 724, the UE 702 estimates the data transmission channel using the received CRS and receives the data using the estimated channel. The estimation of the channel by the UE may mean the estimation of the channel function H of the transmission channel. For example, the received signal y can be expressed as y=Hx+n, where H refers to the channel function, x refers to the transmitted signal, and n refers to noise (including interference signals).

In FIG. 7, the CRS-RS may have the CSI-RS pattern shown in FIG. 5 or 6. For example, assume that the eNB 700 transmits two CSI-RS symbols through two antenna ports through two consecutive subcarriers in the same time resource. Since the transmission mechanism is adopted on two consecutive subcarriers in the same time resource, the beneficial effects of CSI-RS pattern application according to the present invention can be obtained.

Similarly, the CSI-IM can be transmitted by the same pattern as the CSI-RS.

In FIG. 7, since the serving eNB transmits its CSI-IM zero-power CSI-RS in the pattern as shown in FIG. 5 or FIG. 6, the beneficial effects of the application of the CSI-RS pattern according to the present invention can be obtained.

In FIG. 8, the CRS#0 signal 800, the CRS#1 signal 802, and the CSI-RS symbols 810 and 812 for the four CSI-IM ports are transmitted as shown. Referring to the CSI-IM patterns 810 and 812 shown in FIG. 8, CSI-IM symbols are spread in the frequency axis direction while remaining in the same time resource (ie, symbol). That is, the CSI-IM signal can be transmitted by the same pattern as shown for the CSI-RS in FIG. 6. Optionally, eNBs of neighboring cells may transmit zero-power CSI-RS in resources.

Next-generation UEs (eg, LTE-A-capable UEs) can remove interfering signals from the received signals to reduce the packet error of the desired signal. To remove the interference signal, the UE can use the transmission mechanism information of the interference signal and the channel status information. 9 and FIG. 11 illustrate an example of a method of implementing an operation of estimating transmission mechanism information of an interference signal by the UE to remove the interference signal according to the present invention.

The present invention provides new parameters for estimating the information of interference signal transmission mechanism Test signal (hereinafter referred to as "TM-IM"). The new reference signal TM-IM (Transmission Mode Interference Measurement) is a reference signal that helps to perform blind detection of the transmission mechanism information of the cell that generates the strongest interference. The UE can use the TM-IM transmitted by the eNB 900 to estimate the transmission mechanism information of the interference signal, and can use the estimated transmission mechanism information of the interference signal to remove the interference signal from the received signal to further reduce the time when receiving data Packet error.

9 illustrates an example of the operation of an eNB and a UE in a wireless communication system employing TM-IM, which utilizes patterned CSI-RS, according to the present invention.

As in FIG. 7, the process in FIG. 9 is divided into two parts: a CSI feedback part 910 and a data transmission part 930. In the first part 910, the UE 902 uses the reference signal transmitted by the eNB 900 to feed back the channel state information to the eNB 900, and in the second part 930, the eNB 900 uses the channel state information fed back by the UE 902 in the first part 910 Transmit downlink data. The operation of FIG. 9 will be explained in more detail below.

In step 912, the eNB 900 transmits a pilot signal (ie, a reference signal) used by the UE 902 to measure the channel status. The reference signal may be, for example, CSI-RS or CSI-IM.

The CSI-RS or CSI-IM may have the CSI-RS pattern shown in FIG. 5 or FIG. 6.

In step 914, the UE 902 measures the channel state of the serving cell (ie, serving eNB) using the CSI-RS transmitted by the eNB 900 in step 912. In step 916, the UE 902 uses the CSI-IM transmitted by the eNB 900 to measure the small interference Channel status of the zone (ie, interfering eNB).

Unlike step 710 of FIG. 7, as indicated by the dashed box in step 918, the UE 902 can estimate the transmission mechanism information of the interfering cell based on CSI-IM. In FIG. 9, since the serving eNB can transmit its CSI-IM zero-power CSI-RS in the pattern as shown in FIG. 5 or FIG. 6, the UE 902 has a high probability of using CSI-IM to estimate the interference signal. Transmission mechanism information. Such transmission mechanism information may include, for example, transmission mode (TM), PMI, RI, and MCS indicating the modulation mechanism and modulation level.

The UE 902 generates channel state information (of the serving cell) based on the measurement result in step 920 and feeds back the CSI to the eNB 900. The channel status information transmitted to the eNB 900 may include at least one of CQI, PMI, and RI.

In step 932, the eNB 900 uses the channel state information to determine the transmission mechanism, and then transmits the CRS and TM-IM while transmitting the data to the UE 902 via the PDSCH.

In step 934, the UE 902 estimates the data transmission channel using the CRS and receives the data using the estimated channel. The UE 902 may use the channel function H of the transmission channel to estimate the channel. At the same time, the UE 902 may use TM-IM to estimate the transmission mechanism information of the interference signal, and use the estimated transmission mechanism information to remove the interference signal from the received signal and receive data. For example, the transmission mechanism information of the interference signal estimated by the UE may be interference signal parameters, such as the transmission mode (TM), RI, PMI, or MCS calculated in step 918.

In FIG. 9, the serving eNB transmits its TM-IM configuration zero-power CSI-RS in the pattern shown in FIG. 5 or FIG. 6, so the UE 902 has a high probability of using TM-IM Estimate the transmission mechanism information of the interference signal.

10 illustrates an example of TM-IM patterns of four TM-IM ports in a time-frequency resource grid of one RB in the LTE system according to the present invention, the one RB is composed of fourteen symbols on the time axis and Twelve subcarriers on the frequency axis are defined.

In FIG. 10, CRS#0 signal 1000, CRS#1 signal 1002, and TM-IM symbols 1010 and 1012 for four TM-IM ports are transmitted. Referring to the TM-IM patterns 1010 and 1012 shown in FIG. 10, TM-IM symbols are spread in the frequency axis direction at the same time resource. That is, the TM-IM signal can be transmitted in the same pattern as the CSI-RS pattern.

11 illustrates an example of the operation of eNB and UE in a wireless communication system employing CSI-TM-IM according to the present invention, the CSI-TM-IM utilizes a pattern of CSI-RS.

As described above, the present invention provides a new reference signal (hereinafter, referred to as "CSI-TM-IM") for estimating channel state information and interference signal transmission mechanism information. The new reference signal CSI-TM-IM (channel status information-transmission mode-interference measurement) is a reference signal that helps to perform blind detection of transmission mechanism information of interfering cells and helps measure channel status information of interfering cells. The UE can use the CSI-TM-IM transmitted by the eNB to estimate the transmission mechanism information of the interference signal or measure the channel status information. The UE can remove the interference signal from the received signal based on the estimated transmission mechanism information of the interference signal to further reduce packet errors when receiving data, and can improve feedback accuracy by using the estimated channel state information of the interference signal.

The process of Figure 11 is divided into two parts: CSI feedback part 1110 and data 料 Transmission Part 1130. The UE 1102 uses the reference signal transmitted by the eNB 1100 in the feedback section 1110 to transmit channel state information, and the eNB 1100 uses the channel state information in the data transmission section 1130 to transmit downlink data. The operation of FIG. 11 will be explained in more detail below.

In step 1112, the eNB 1100 transmits the pilot signal (ie, reference signal) used by the UE 1102 to measure the channel status. The reference signal may be, for example, CSI-RS or CSI-IM.

The CSI-RS may have a CSI-RS pattern as shown in FIG. 5 or FIG. 6. Similarly, CSI-IM can be transmitted by the same pattern as that of CSI-RS.

In step 1114, the UE 1102 uses the CSI-RS transmitted by the eNB 1100 to measure the channel status information of the serving cell (ie, serving eNB). In step 1116, the UE 1102 uses the CSI-IM transmitted by the eNB 1100 and the interfering eNB to measure the channel state information of the interfering cell (ie, interfering eNB).

Unlike step 710 of FIG. 7, as indicated by the dashed box in step 1118, the UE 1102 may estimate the transmission mechanism information of the interfering cell based on CSI-IM. In FIG. 11, since the serving eNB can transmit its CSI-IM zero-power CSI-RS in the pattern shown in FIG. 5 or FIG. 6, the UE 1102 has a high probability to use CSI-IM to estimate the interference signal transmission Mechanism information. The transmission mechanism information may include, for example, transmission mode (TM), PMI, RI, and MCS indicating the modulation mechanism and modulation level.

In step 1120, the UE 1102 generates channel status information (of the serving cell) based on the measurement result and transmits the CSI to the eNB 1100. The channel status information transmitted to the eNB 1100 may include at least one of CQI, PMI, and RI.

In step 1132, the eNB 1100 uses the channel state information to determine the transmission mechanism and transmits the CRS and CSI-TM-IM while transmitting the data to the UE 1102 via the PDSCH. Similarly, CSI-TM-IM can be transmitted by the same pattern as shown in FIGS. 5 and 6.

In step 1134, the UE 1102 estimates the data transmission channel using the CRS, and then uses the estimated channel to receive the data. The UE 1102 may use the channel function H to estimate the channel. At the same time, the UE 1102 can use CSI-TM-IM to estimate the transmission mechanism information of the interference signal, and use the estimated transmission mechanism information to remove the interference signal from the received signal and receive data. For example, the transmission mechanism information of the interference signal estimated by the UE may be interference signal parameters, such as transmission mode (TM), RI, PMI, or MCS.

In FIG. 11, the serving eNB transmits its CSI-TM-IM zero-power CSI-RS in the pattern shown in FIG. 5 or FIG. 6, and the UE 1102 has a high probability of using CSI-TM-IM to estimate the interference signal transmission. Mechanism information.

In addition, CSI-TM-IM can be used to estimate CSI as feedback CSI. For example, in step 1136, the UE 1102 uses CSI-TM-IM to estimate the transmission mechanism information of the interference signal, and determines the channel state information for transmission re-feedback. In other words, one CSI-TM-IM can be used for both the interference transmission mechanism estimation in data reception and the CSI estimation in CSI feedback.

FIG. 12 illustrates an example of CSI-TM-IM of four CSI-TM-IM ports in a time-frequency resource grid of one RB in the LTE system according to the present invention. The one RB is composed of fourteen on the time axis. Symbols and twelve subcarrier boundaries on the frequency axis set.

In FIG. 12, CRS#0 signal 1200, CRS#1 signal 1202, and CSI-TM-IM symbols 1210 and 1212 for four CSI-TM-IM ports are transmitted. Referring to the CSI-TM-IM patterns 1210 and 1212 shown in FIG. 12, the CSI-TM-IM symbols are spread in the frequency axis direction at the same time resource. That is, the CSI-TM-IM signal can be transmitted in the same pattern as the CSI-RS pattern.

13 illustrates an example of a method in which an eNB transmits information for identifying reference signals or CSI process information to a UE according to the present invention.

As shown in FIG. 13, before the operation of transmitting the reference signal and channel state information feedback described in FIGS. 7 to 12, the eNB 1300 may transmit reference signal identification information or CSI process information to the UE 1302 in step 1310.

The reference signal identification information corresponds to indicating to the UE at least one of reference signals for channel measurement (ie, CSI-RS, CSI-IM, TM-IM, CSI-TM-IM, and zero-power CSI-RS) For information, the reference signal is transmitted based on the pattern according to the invention. The reference signal identification information may be transmitted by radio resource control (Radio Resource Control, RRC) layer transmission or transmitted by physical layer downlink control information (DCI).

CSI process information (eg, for LTE systems) corresponds to information indicating the following: selected from reference signals used for channel measurement (ie, CSI-RS, CSI-RS, CSI-IM, TM-IM, CSI-TM-IM And zero power CSI-RS) and the location of the resource to be used to transmit the reference signal, the reference signal is transmitted based on the pattern according to the present invention. Preferably, the CSI process information can be A piece of information including multiple pieces of information about groups of 3 to 4 reference signals. CSI process information can be transmitted by RRC layer signaling or by DCI of the physical layer.

14 is a block diagram of an eNB device according to the present invention.

The eNB device 1400 may include a transceiver 1410 (eg, a radio frequency (RF) chip) that can communicate with the UE via signals and a controller 1420 (eg, a modem chip) for controlling the transceiver 1410. The transceiver 1410 and the controller 1420 may also be implemented as one component (eg, chipset).

The controller 1420 is a component for implementing the reference signal according to the present invention and the data transmission method performed by the eNB. That is, all operations of the above-mentioned eNB can be understood as being implemented by the controller 1420.

15 is a block diagram of a UE device according to the present invention.

The UE device 1500 may include a transceiver 1510 that can communicate with an eNB or another UE via a signal, and a controller 1520 for controlling the transceiver 1510. The transceiver 1510 and the controller 1520 can also be implemented as one component.

The controller 1520 is a component for implementing the transmission/reception method of the UE according to the present invention. That is, all operations of the UE described above can be understood as being implemented by the controller 1520.

The system configuration, examples of time-frequency resource grids, examples of methods, and block diagrams of devices shown in FIGS. 1 to 15 are not intended to limit the scope of the present invention. That is, all descriptions, time-frequency resource grid arrangements, configurations, or operation steps related to FIGS. 1 to 15 should not be understood as essential elements for implementing the present invention, and Without departing from the scope of the present invention, the present invention can be implemented using only some of the elements.

The above-mentioned operation can be implemented by providing the memory device storing the corresponding program code to any constituent unit of the communication system entity, the base station, or the terminal. That is, the communication system entity, terminal, base station, or terminal or base station controller uses a processor or a central processing unit (CPU) to read and execute the program code stored in the memory device to Perform the above operation.

Various components, modules, etc. can be implemented by hardware circuits (e.g., logic circuits based on complementary metal oxide semiconductors), firmware, software, and/or a combination of hardware and firmware, and/or embedded in machine-readable media Software to implement. As an example, various electronic configurations and methods may be performed using, for example, transistors, logic gates, and application specific integrated circuits (ASICs).

Various components, modules, etc. can be implemented by hardware circuits (e.g., logic circuits based on complementary metal oxide semiconductors), firmware, software, and/or a combination of hardware and firmware, and/or embedded in machine-readable media Software to implement. As an example, various electronic configurations and methods may be performed using, for example, transistors, logic gates, and application specific integrated circuits (ASICs).

500‧‧‧CRS#0 signal

502‧‧‧CRS#1 signal

510‧‧‧CSI-RS symbol

Claims (22)

A method for user equipment (UE) in a cellular communication system includes receiving a channel state information reference signal (CSI-RS) transmitted according to a pattern in a time-frequency resource grid, the pattern is based on Determine the transmission mechanism of the evolved NodeB (eNB); use the CSI-RS measurement and the status of the eNB's transmission channel; generate channel state information based on the measurement; use the channel state information as feedback transmission To the eNB; receive a reference signal (CRS) for a specific cell from the eNB; use the CRS to estimate the transmission channel; and use the estimated channel to obtain data transmitted on the transmission channel, When the transmission mechanism of the eNB is one of spatial frequency block code (SFBC), SFBC-frequency switched transmission diversity (FSTD), and cyclic delay diversity-spatial multiplexing (CDD-SM), The pattern corresponds to a pattern in which two consecutive CSI-RS symbols are transmitted by two consecutive subcarriers on the frequency axis of the time-frequency resource grid. The method as described in item 1 of the patent application scope further includes: receiving CSI interference measurement (CSI-IM) transmitted according to the pattern. The method according to item 2 of the patent application scope, wherein the CSI-IM is transmitted according to the zero-power CSI-RS of the pattern. The method described in item 1 of the patent application scope further includes: Receiving a first reference signal, the first reference signal is transmitted according to the pattern and used to estimate transmission mechanism information of the interference signal; and the first reference signal is used to estimate the transmission mechanism information of the interference signal And use the estimated transmission mechanism information of the interference signal to remove the interference signal from the downlink signal. The method according to item 1 of the patent application scope further includes: receiving a second reference signal, the second reference signal is transmitted according to the pattern and is used to estimate transmission mechanism information of the interference signal and measure the Channel state information of the interference signal; use the second reference signal to estimate the transmission mechanism information of the interference signal, and use the estimated transmission mechanism information of the interference signal to remove the signal from the downlink signal The interference signal; using the estimated transmission mechanism information of the interference signal to generate the channel state information of the UE; and transmitting the generated channel state information as feedback again. The method as described in item 1 of the patent application scope, wherein the channel status information includes a channel quality indicator (CQI), a level indicator (RI), and a precoding matrix indicator that indicate modulation and coding mechanisms (MCS) (PMI). The method according to item 4 of the patent application scope, wherein the transmission mechanism information of the interference signal includes at least one of parameters of the interference signal such as the following: a transmission mode (TM), a precoding matrix indicator (PMI), grade index Indicator (RI), and Modulation Level (MOD). The method as described in item 1 of the patent application scope, further including before the step of receiving the CSI-RS: receiving information indicating at least one of the following: CSI-RS, zero-power CSI-RS, CSI interference Measurement (CSI-IM), a first reference signal used to estimate the transmission mechanism information of the interference signal, and a second reference signal used to estimate the transmission mechanism information and measure the channel state information of the interference signal, so The information is communicated through the radio resource control (RRC) layer or as downlink control information (DCI). The method as described in item 1 of the patent application scope further includes before the step of receiving the CSI-RS: receiving information indicating the CSI process, regarding at least one of the following: CSI-RS, CSI interference amount Measurement (CSI-IM), a first reference signal used to estimate the transmission mechanism information of the interference signal, and a second reference signal used to estimate the transmission mechanism information and measure the channel state information of the interference signal, wherein The CSI-RS, the CSI-IM, the first reference signal, and the second reference signal are transmitted according to the pattern. A method for an evolved NodeB (eNB) in a cellular communication system includes: transmitting a channel state information reference signal (CSI-RS) to a user equipment (UE) according to a pattern in a time-frequency resource grid, The pattern is determined based on the transmission mechanism of the eNB; receiving channel state information of the UE generated by using the CSI-RS; And transmitting downlink signals including data and cell-specific reference signals (CRS), where the transmission mechanism at the eNB is spatial frequency block code (SFBC), SFBC-frequency switched transmission diversity (FSTD) , And one of cyclic delay diversity-spatial multiplexing (CDD-SM), the pattern corresponds to where two consecutive subcarriers on the frequency axis of the time-frequency resource grid are used to transmit two The pattern of consecutive CSI-RS symbols. The method as described in item 10 of the patent application scope further includes: transmitting CSI interference measurement (CSI-IM) according to the pattern. The method according to item 11 of the patent application range, wherein the CSI-IM is transmitted according to the zero-power CSI-RS of the pattern. The method according to item 10 of the patent application scope further includes: transmitting a first reference signal according to the pattern, the first reference signal is used by the UE to estimate transmission mechanism information of the interference signal. The method according to item 10 of the patent application scope further includes: transmitting a second reference signal according to the pattern, the second reference signal is used by the UE to estimate transmission mechanism information and measure the channel state of the interference signal Information; and receiving channel state information of the UE generated based on the transmission mechanism information of the interference signal, the transmission mechanism information of the interference signal is estimated using the second reference signal. The method according to item 10 of the patent application scope, wherein the channel The status information includes at least one of a channel quality indicator (CQI), a level indicator (RI), and a precoding matrix indicator (PMI) indicating modulation and coding mechanism (MCS). The method according to item 13 of the patent application range, wherein the transmission mechanism information of the interference signal includes at least one of parameters of the interference signal such as the following: a transmission mode (TM), a precoding matrix indicator (PMI), level indicator (RI), and modulation level (MOD). The method as described in item 10 of the patent application scope further includes before the step of transmitting the CSI-RS: transmitting information indicating at least one of the following: CSI-RS, zero-power CSI-RS, CSI interference Measurement (CSI-IM), a first reference signal used to estimate the transmission mechanism information of the interference signal, and a second reference signal used to estimate the transmission mechanism information and measure the channel state information of the interference signal, so The information is communicated through the radio resource control (RRC) layer or as downlink control information (DCI). The method as described in item 10 of the patent application scope further includes before the step of transmitting the CSI-RS: transmitting information indicating the CSI process regarding at least one of the following: CSI-RS, CSI interference amount Measurement (CSI-IM), a first reference signal used to estimate the transmission mechanism information of the interference signal, and a second reference signal used to estimate the transmission mechanism information and measure the channel state information of the interference signal, wherein The CSI-RS, the CSI-IM, the first reference signal, and the second reference signal are transmitted according to the pattern. A user equipment (UE) used in a cellular communication system includes a controller that receives a channel state information reference signal (CSI-RS) transmitted according to a pattern in a time-frequency resource grid, the pattern is Determined based on the evolved NodeB (eNB) transmission mechanism; using the CSI-RS measurement and the status of the eNB's transmission channel; generating channel state information based on the measurement; using the channel state information as feedback Transmitting to the eNB; receiving a reference signal (CRS) for a specific cell from the eNB; using the CRS to estimate the transmission channel; and using the estimated channel to obtain data transmitted on the transmission channel And a transceiver that receives the CSI-RS under the control of the controller, transmits the channel status information, and receives the CRS and the transmission channel, wherein the transmission mechanism at the eNB is a spatial frequency When one of block code (SFBC), SFBC-frequency switched transmission diversity (FSTD), and cyclic delay diversity-spatial multiplexing (CDD-SM), the pattern corresponds to the time-frequency The pattern of two consecutive CSI-RS symbols is transmitted by two consecutive subcarriers on the frequency axis of the resource grid. An evolved NodeB (eNB) used in a cellular communication system, including: a controller that transmits a channel state information reference signal (CSI-RS) to a user equipment (UE) according to a pattern in a time-frequency resource grid , The pattern is determined based on the transmission mechanism of the eNB; receiving channel state information of the UE generated by using the CSI-RS; and transmitting reference information including data and specific cells Number (CRS) downlink signal; and a transceiver that transmits the CSI-RS under the control of the controller, receives the channel status information, and transmits the downlink signal, where the When the transmission mechanism is one of spatial frequency block code (SFBC), SFBC-frequency switched transmission diversity (FSTD), and cyclic delay diversity-spatial multiplexing (CDD-SM), the pattern corresponds to The pattern of two consecutive CSI-RS symbols is transmitted by two consecutive subcarriers on the frequency axis of the time-frequency resource grid. A chip set for user equipment (UE) in a cellular communication system is used to: receive a channel state information reference signal (CSI-RS) transmitted according to a pattern in a time-frequency resource grid, the pattern It is determined by the evolved NodeB (eNB) based on the transmission mechanism; using the CSI-RS to measure the state of the transmission channel with the eNB; generating channel state information based on the measurement; using the channel state information as Feedback transmission to the eNB; receiving a reference signal (CRS) for a specific cell from the eNB; using the CRS to estimate the transmission channel; and using the estimated channel to obtain the transmission on the transmission channel Data, wherein the transmission mechanism at the eNB is one of spatial frequency block code (SFBC), SFBC-frequency switched transmission diversity (FSTD), and cyclic delay diversity-space multiplexing (CDD-SM) , The pattern corresponds to A pattern of two consecutive CSI-RS symbols is transmitted by two consecutive subcarriers on the frequency axis of the time-frequency resource grid. A chip set used in an evolved NodeB (eNB) in a cellular communication system to transmit a channel state information reference signal (CSI-RS) to a user equipment (UE) according to a pattern in a time-frequency resource grid ), the pattern is determined based on the transmission mechanism of the eNB; receiving channel state information of the UE generated by using the CSI-RS; and transmitting downlink including data and a reference signal (CRS) for a specific cell Link signal, wherein the transmission mechanism at the eNB is space frequency block code (SFBC), SFBC-frequency switched transmission diversity (FSTD), and cyclic delay diversity-space multiplexing (CDD-SM) In one case, the pattern corresponds to a pattern in which two consecutive CSI-RS symbols are transmitted by two consecutive subcarriers on the frequency axis of the time-frequency resource grid.

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