WO2017209391A1 - Method for receiving csi-rs in wireless communication system and apparatus therefor - Google Patents

Abstract

A method by which a terminal receives a channel state information-reference signal (CSI-RS) in a wireless communication system comprises the steps of: receiving control information including information for indicating whether a resource for a CSI-RS is allocated in a specific subframe; and receiving, in a downlink control zone, the CSI-RS on the basis of the control information, when a data zone of the specific subframe is allocated to a downlink data zone and the control information indicates that the resource for the CSI-RS is allocated in the specific subframe.

Description

Method for receiving CSI-RS in wireless communication system and apparatus therefor

The present invention relates to wireless communication, and more particularly, to a method and apparatus for receiving the CSI-RS in a wireless communication system.

The 3GPP LTE 3rd Generation Partnership Project Long Term Evolution (LTE) system is designed as a frame structure with a 1ms transmission time interval (TTI), and the data request delay time is 10ms for video applications. However, future 5G technologies will require lower latency data transmissions with the emergence of new applications such as real-time control and tactile internet, and 5G data demand latency will be lowered to 1ms. It is expected.

However, there is a problem that the conventional 1 ms TTI frame structure cannot satisfy the 1 ms data request delay. 5G aims to provide about 10 times less data delay than before. In the new frame structure of the 5G system, detailed design related to CSI-RS transmission is required.

An object of the present invention is to provide a method for a terminal to receive a channel state information reference signal (CSI-RS) in a wireless communication system.

Another object of the present invention is to provide a terminal for receiving a channel state information reference signal (CSI-RS) in a wireless communication system.

Technical problems to be achieved in the present invention are not limited to the above technical problems, and other technical problems that are not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above technical problem, a method of receiving a channel state information reference signal (CSI-RS) by the terminal in a wireless communication system, the resource for the CSI-RS in a specific subframe Receiving control information including information indicating whether assigned; And when the data zone of the specific subframe is allocated to a downlink data zone and the control information indicates that resources for the CSI-RS are allocated to the specific subframe, the CSI-RS is based on the control information. It can be received in the downlink control zone. The CSI-RS may be received in the last symbol of the downlink control zone. The control information may be received in the specific subframe. Resources for the CSI-RS may be allocated to the downlink data zone of the specific subframe. The control information may further include information indicating the number of antenna ports for the CSI-RS. The control information may further include information about the location of the resource to which the CSI-RS is allocated. The information on the location of the resource to which the CSI-RS is allocated may be location information in the frequency domain. The CSI-RS may be received in a downlink control zone of the specific subframe. The CSI-RS may be received in a subsequent subframe corresponding to the offset value in the specific subframe based on a predefined or indicated offset value. The method includes performing channel measurements based on the CSI-RS; And transmitting a measurement result according to the channel measurement through an uplink control zone or an uplink data zone.

In order to achieve the above technical problem, a terminal for receiving a channel state information reference signal (CSI-RS) in a wireless communication system, the receiver; And a processor, wherein the processor is configured to control the receiver to receive control information including information indicating whether a resource for the CSI-RS is allocated to a specific subframe, and data of the specific subframe. When a zone is allocated to a downlink data zone and the control information indicates that a resource for the CSI-RS is allocated to the specific subframe, the receiver transmits the CSI-RS to a downlink control zone based on the control information. Can be controlled to receive from. The processor may control the receiver to receive the CSI-RS in the last symbol of the downlink control zone. The processor may control the receiver to receive the control information in the specific subframe.

Resources for the CSI-RS may be allocated to the downlink data zone of the specific subframe. The terminal further includes a transmitter, the processor performs a channel measurement based on the CSI-RS, and controls the transmitter to transmit a measurement result according to the channel measurement through an uplink control zone or an uplink data zone can do.

The CSI-RS transmission scheme proposed in the present invention enables efficient channel state measurement in a self-contained frame structure in stand-alone NR.

Effects obtained in the present invention are not limited to the above-mentioned effects, and other effects not mentioned above may be clearly understood by those skilled in the art from the following description. will be.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included as part of the detailed description in order to provide a thorough understanding of the present invention, provide an embodiment of the present invention and together with the description, illustrate the technical idea of the present invention.

1 is a block diagram showing the configuration of a base station 105 and a terminal 110 in a wireless communication system 100.

FIG. 2 is a diagram for explaining correlation with IMT 2020 core performance requirements for 5G and 5G performance requirements for each service scenario.

3 is a diagram illustrating an LTE / LTE-A frame structure.

4 is a diagram illustrating an example of an FDD / TDD frame structure in an LTE / LTE-A system.

5 is a diagram exemplarily illustrating a self-contained subframe structure.

6 is a diagram illustrating a self-contained subframe structure of stand-alone New RAT.

7 is a diagram illustrating allocation of CSI-RS of a self-contained subframe structure.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The detailed description, which will be given below with reference to the accompanying drawings, is intended to explain exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced. The following detailed description includes specific details in order to provide a thorough understanding of the present invention. However, one of ordinary skill in the art appreciates that the present invention may be practiced without these specific details. For example, the following detailed description will be described in detail on the assumption that the mobile communication system is a 3GPP LTE, LTE-A system, but is also applied to any other mobile communication system except for the specific matters of 3GPP LTE, LTE-A. Applicable

In some instances, well-known structures and devices may be omitted or shown in block diagram form centering on the core functions of the structures and devices in order to avoid obscuring the concepts of the present invention. In addition, the same components will be described with the same reference numerals throughout the present specification.

In addition, in the following description, it is assumed that a terminal collectively refers to a mobile or fixed user terminal device such as a user equipment (UE), a mobile station (MS), an advanced mobile station (AMS), and the like. In addition, it is assumed that the base station collectively refers to any node of the network side that communicates with the terminal such as a Node B, an eNode B, a Base Station, and an Access Point (AP).

In a mobile communication system, a user equipment may receive information from a base station through downlink, and the terminal may also transmit information through uplink. The information transmitted or received by the terminal includes data and various control information, and various physical channels exist according to the type and purpose of the information transmitted or received by the terminal.

In addition, specific terms used in the following description are provided to help the understanding of the present invention, and the use of such specific terms may be changed to other forms without departing from the technical spirit of the present invention.

1 is a block diagram showing the configuration of a base station 105 and a terminal 110 in a wireless communication system 100.

Although one base station 105 and one terminal 110 (including a D2D terminal) are shown to simplify the wireless communication system 100, the wireless communication system 100 may include one or more base stations and / or one or more base stations. It may include a terminal.

Referring to FIG. 1, the base station 105 includes a transmit (Tx) data processor 115, a symbol modulator 120, a transmitter 125, a transmit / receive antenna 130, a processor 180, a memory 185, and a receiver ( 190, a symbol demodulator 195, and a receive data processor 197. The terminal 110 transmits (Tx) the data processor 165, the symbol modulator 170, the transmitter 175, the transmit / receive antenna 135, the processor 155, the memory 160, the receiver 140, and the symbol. It may include a demodulator 155 and a receive data processor 150. Although the transmit and receive antennas 130 and 135 are shown as one in the base station 105 and the terminal 110, respectively, the base station 105 and the terminal 110 are provided with a plurality of transmit and receive antennas. Accordingly, the base station 105 and the terminal 110 according to the present invention support a multiple input multiple output (MIMO) system. In addition, the base station 105 according to the present invention may support both a single user-MIMO (SU-MIMO) and a multi-user-MIMO (MU-MIMO) scheme.

On the downlink, the transmit data processor 115 receives the traffic data, formats the received traffic data, codes it, interleaves and modulates (or symbol maps) the coded traffic data, and modulates the symbols ("data"). Symbols "). The symbol modulator 120 receives and processes these data symbols and pilot symbols to provide a stream of symbols.

The symbol modulator 120 multiplexes the data and pilot symbols and sends it to the transmitter 125. In this case, each transmission symbol may be a data symbol, a pilot symbol, or a signal value of zero. In each symbol period, pilot symbols may be sent continuously. The pilot symbols may be frequency division multiplexed (FDM), orthogonal frequency division multiplexed (OFDM), time division multiplexed (TDM), or code division multiplexed (CDM) symbols.

Transmitter 125 receives the stream of symbols and converts it into one or more analog signals, and further adjusts (eg, amplifies, filters, and frequency upconverts) the analog signals to provide a wireless channel. Generates a downlink signal suitable for transmission via the transmission antenna 130, the transmission antenna 130 transmits the generated downlink signal to the terminal.

In the configuration of the terminal 110, the receiving antenna 135 receives the downlink signal from the base station and provides the received signal to the receiver 140. Receiver 140 adjusts the received signal (eg, filtering, amplifying, and frequency downconverting), and digitizes the adjusted signal to obtain samples. The symbol demodulator 145 demodulates the received pilot symbols and provides them to the processor 155 for channel estimation.

The symbol demodulator 145 also receives a frequency response estimate for the downlink from the processor 155 and performs data demodulation on the received data symbols to obtain a data symbol estimate (which is an estimate of the transmitted data symbols). Obtain and provide data symbol estimates to a receive (Rx) data processor 150. Receive data processor 150 demodulates (ie, symbol de-maps), deinterleaves, and decodes the data symbol estimates to recover the transmitted traffic data.

The processing by symbol demodulator 145 and receiving data processor 150 is complementary to the processing by symbol modulator 120 and transmitting data processor 115 at base station 105, respectively.

The terminal 110 is on the uplink, and the transmit data processor 165 processes the traffic data to provide data symbols. The symbol modulator 170 may receive and multiplex data symbols, perform modulation, and provide a stream of symbols to the transmitter 175. The transmitter 175 receives and processes a stream of symbols to generate an uplink signal. The transmit antenna 135 transmits the generated uplink signal to the base station 105. The transmitter and the receiver in the terminal and the base station may be configured as one radio frequency (RF) unit.

In the base station 105, an uplink signal is received from the terminal 110 through the reception antenna 130, and the receiver 190 processes the received uplink signal to obtain samples. The symbol demodulator 195 then processes these samples to provide received pilot symbols and data symbol estimates for the uplink. The received data processor 197 processes the data symbol estimates to recover the traffic data transmitted from the terminal 110.

Processors 155 and 180 of the terminal 110 and the base station 105 respectively instruct (eg, control, coordinate, manage, etc.) operations at the terminal 110 and the base station 105, respectively. Respective processors 155 and 180 may be connected to memory units 160 and 185 that store program codes and data. The memory 160, 185 is coupled to the processor 180 to store the operating system, applications, and general files.

The processors 155 and 180 may also be referred to as controllers, microcontrollers, microprocessors, microcomputers, or the like. The processors 155 and 180 may be implemented by hardware or firmware, software, or a combination thereof. When implementing embodiments of the present invention using hardware, application specific integrated circuits (ASICs) or digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs) configured to perform the present invention. Field programmable gate arrays (FPGAs) may be provided in the processors 155 and 180.

Meanwhile, when implementing embodiments of the present invention using firmware or software, the firmware or software may be configured to include a module, a procedure, or a function for performing the functions or operations of the present invention, and to perform the present invention. The firmware or software configured to be may be provided in the processors 155 and 180 or stored in the memory 160 and 185 to be driven by the processors 155 and 180.

The layers of the air interface protocol between the terminal and the base station between the wireless communication system (network) are based on the lower three layers of the open system interconnection (OSI) model, which is well known in the communication system. ), And the third layer L3. The physical layer belongs to the first layer and provides an information transmission service through a physical channel. A Radio Resource Control (RRC) layer belongs to the third layer and provides control radio resources between the UE and the network. The terminal and the base station may exchange RRC messages through the wireless communication network and the RRC layer.

In the present specification, the processor 155 of the terminal and the processor 180 of the base station process the signals and data, except for the function of receiving or transmitting the signal and the storage function of the terminal 110 and the base station 105, respectively. For convenience of description, the following description does not specifically refer to the processors 155 and 180. Although not specifically mentioned by the processors 155 and 180, it may be said that a series of operations such as data processing is performed rather than a function of receiving or transmitting a signal.

The present invention proposes a new and various frame structure for the fifth generation (5G) communication system. Next-generation 5G systems can be categorized into Enhanced Mobile BroadBand (eMBB) / Ultra-reliable Machine-Type Communications (uMTC) / Massive Machine-Type Communications (mMTC). eMBB is a next generation mobile communication scenario with characteristics such as High Spectrum Efficiency, High User Experienced Data Rate, High Peak Data Rate, and uMTC is a next generation mobile communication scenario with characteristics such as Ultra Reliable, Ultra Low Latency, Ultra High Availability, etc. For example, V2X, Emergency Service, Remote Control), and mMTC are next generation mobile communication scenarios having low cost, low energy, short packet, and mass connectivity (eg IoT).

FIG. 2 is a diagram for explaining correlation with IMT 2020 core performance requirements for 5G and 5G performance requirements for each service scenario.

2 illustrates the correlation between the core performance requirements presented in IMT 2020 for 5G and the 5G performance requirements for each service scenario.

In particular, uMTC Service has very limited Over The Air (OTA) Latency Requirement, and requires high mobility and high reliability (OTA Latency: <1ms, Mobility:> 500km / h, BLER: <10-6).

3 is a diagram illustrating an LTE / LTE-A frame structure.

3 shows a basic concept of a frame structure of LTE / LTE-A. One frame is composed of 10 ms and 10 1 ms subframes. One subframe consists of two 0.5 ms slots, and one slot consists of seven Orthogonal Frequency Division Multiplexing (OFDM) symbols. One resource block (RB) is defined by 12 subcarriers spaced at 15 kHz and 7 OFDM symbols. The base station transmits a Primary Synchronization Signal (PSS) for Synchronization, a Secondary Synchronization Signal (SSS), and a Physical Broadcast Channel (PBCH) for system information at the Center Frequency 6RB. Here, the frame structure, the signal, and the channel positions may be different according to a normal / extended CP (cyclic prefix), a time division duplex (TDD), and a frequency division duplex (FDD).

4 is a diagram illustrating an example of an FDD / TDD frame structure in an LTE / LTE-A system.

Referring to FIG. 4, in the case of the FDD frame structure, downlink and uplink frequency bands are divided, and in the case of the TDD frame structure, the downlink region and the uplink region are divided in subframe units in the same band. In the case of the TDD frame structure, a special subframe region exists between the downlink region and the uplink region, and the special subframe is used for guard period (GP) or some data transmission to solve the interference problem between downlink and uplink. .

5 is a diagram exemplarily illustrating a self-contained subframe structure.

5 shows a self-contained subframe structure for satisfying the low latency requirement among the 5G performance requirements. In the TDD-based self-contained subframe structure, resource sections for downlink and uplink (eg, downlink control channel and uplink control channel) exist in one subframe, and there is an interference problem between downlink and uplink. There is a resource section for data transmission and GP for solving the problem.

5A illustrates an example of a structure of a self-contained subframe, in which subframes are configured in the order of resource intervals for downlink-uplink-data, and a GP exists between the resource intervals. In (a) of FIG. 5, the downlink resource interval indicated by DL may be a resource interval for a downlink control channel, and the uplink resource interval indicated by UL may be a resource interval for an uplink control channel.

5 (b) shows another example of a self-contained subframe structure, in which subframes are configured in the order of resource sections for downlink-data-uplink, and the GP exists only before the uplink resource section. Likewise, in FIG. 5B, the downlink resource interval indicated by DL may be a resource interval for a downlink control channel, and the uplink resource interval indicated by UL may be a resource interval for an uplink control channel.

New RAT (NR) can support stand-alone. Particularly, in case of 6GHz or less, it is preferable to support stand-alone because it has wider coverage than 6GHz or more. For this reason, the present invention proposes a channel state information-reference signal (CSI-RS) for supporting stand-alone operation.

First, in an initial access process of a terminal for stand alone operation, there is a process of obtaining a synchronization process and system information and transmitting a RACH (Random Access CHannel). Therefore, signals and channels for a synchronization signal (PSS) / Secondary Synchronization Signal (SSS) and system information (eg, a physical broadcast channel (xPBCH)) should be considered. In order to support ultra-reliable low latency communication (URLLC), one of the use cases, short TTI (Transmit Time Interval) can be considered, so that the existing 14 symbols are replaced by 7 symbols instead of 1 subframe. Consider the configured subframe, which can be seen that the normal TTI is composed of 14 symbols and the short TTI is composed of seven symbols, which are half of those cells-a cell specific RS (CRS) is used for all subframes and full bands. New RAT (NR) does not include CRSs flying across all subframes and full bands in order to reduce the loss of flexibility due to the allocation to R. However, the new RAT (NR) does not include CRSs that fly through existing CRSs. RSs need to be redesigned to replace this capability, one of which is called the RS for RRM measurement, which is called RRM-RS, which is transmitted in wideband, but with downlink channel conditions. Since a reference signal for channel status measurement is not defined, the present invention proposes a new CSI-RS transmission method.

The proposals of the present invention can be applied to the self-contained subframe structure described in FIG. 5 and the new frame structure for the 5G TDD system. In addition, the present invention can be equally applied to an adaptive / self-contained frame structure. In the present invention, the name "zone" refers to a physical resource and may also be referred to as a channel, a zone, or the like.

6 is a diagram illustrating a self-contained subframe structure of stand-alone New RAT.

Referring to FIG. 6, a CSI-RS may be transmitted in a fifth symbol of Subframe # N. Details of the CSI-RS design method are as follows.

(1) In a self-contained subframe, when a data zone is allocated to a downlink data zone (eg, an xPDSCH zone), the base station transmits a CSI-RS in the last OFDM symbol of the last zone of the downlink data zone.

In order not to affect the data decoding as much as possible for low latency, the CSI-RS is multiplexed by frequency division multiplexing (FDM) in the last OFDM symbol. To achieve low latency, the receiver should perform fast data decoding and perform ACK / NACK transmission in the subframe where the data is received or as close as possible. Therefore, it is necessary to minimize the data decoding time by allocating the CSI-RS zone that cannot assist in decoding downlink data of the frame to the rear of the data zone. In addition, if the CSI-RS zone for CSI-RS transmission is capable of data decoding during GP, and ACK / NACK encoding is possible, the UE is a fast ACK in the uplink control zone (eg, xPUCCH zone) of the corresponding subframe / NACK transmission can be performed.

(2) The base station transmits the CSI-RS periodically or aperiodically in the time domain, and the allocation / transmission of the CSI-RS may be indicated through downlink control information (DCI) of the base station.

In the case of the periodic CSI-RS, the period is a common control information (Common Control Information) (eg, MIB (Master Information Block) or SIB (System Information Block), RRC (Radio Resource Control) signaling or the base station terminal It may be defined as the default assignment of the system, or it may operate without instructions.

For aperiodic CSI-RS, the base station schedules aperiodic CSI-RS transmission with DCI. The base station may indicate to the UE whether or not the corresponding subframe is a subframe for transmitting the CSI-RS in a DCI (eg, DCI 1 bit) in the corresponding subframe. The number of antenna ports of the aperiodic CSI-RS may be defined as the base station instructs the terminal through RRC signaling or additional bits of the DCI or is defined as a default assignment of the system and may not have an indication. In order not to wait for the periodic CSI-RS, the base station transmits the aperiodic CSI-RS to the terminal, and the low latency downlink service may be enabled by quickly receiving feedback from the terminal.

(3) The terminal transmits the CSI-RS in the subband or wideband on the frequency domain.

Wideband based CSI-RS may be allocated to secure scheduling gain for the wideband, and in this case, the base station may indicate the allocation of the wideband based CSI-RS to the terminal through additional bits of RRC signaling or DCI. It may be defined as a default assignment of the system or operated without indication. The base station may allocate a subband-based CSI-RS to secure the resources of the xPDSCH, in which case it is indicated through additional bits of RRC signaling or DCI. Based only on long term channel gain information, the base station may allocate subband-based CSI-RS only for channel measurement for a specific band, and in this case, may indicate through RRC signaling or additional bits of DCI. have. For channel measurement only for a specific user (or terminal), the base station may allocate a subband-based CSI-RS, in which case the base station may indicate to the terminal through additional bits of RRC signaling or DCI.

(4) By the base station scheduling, the terminal may measure the entire CSI-RS wideband CSI-RS or only some subbands.

For channel state measurement for downlink of the terminal, the base station may allocate the terminal-specific measurement region for the CSI-RS region. The area allocated to the measurement by the base station scheduling may be instructed by the base station to the terminal through additional bits of the RRC signaling or DCI. When measurement on the wideband of the terminal is required by scheduling of the base station, the terminal may perform measurement on the wideband CSI-RS. When measurement on the subband of the terminal is required by scheduling of the base station, the terminal may perform measurement on the subband CSI-RS. Here, the subbands may be single or multiple. In the case of multiple subbands, the position of the subbands in the frequency domain may be continuous or distributed. By the scheduling of the base station, the measurement areas of multiple terminals may overlap. For example, the area measured by the terminal 1 on the wideband or subband can also measure the channel based on the CSI-RS in the same area as the terminal 2. The areas where the measurements are made may overlap completely or only partially.

(5) The UE may feed back measurement information measured based on the CSI-RS to the base station through an uplink control zone (eg, xPUCCH) or an uplink data zone (eg, xPUSCH). Figure 7 illustrates on the resource grid for the above-mentioned allocation of CSI-RS.

7 is a diagram illustrating allocation of CSI-RS of a self-contained subframe structure.

Referring to FIG. 7, subframe #L illustrates a subframe in which the CSI-RS is not transmitted, and subframe #N illustrates a subframe in which the CSI-RS is transmitted. Numerals 1 to 8 shown in FIG. 7 mean CSI-RS for each antenna port (that is, an antenna port index for CSI-RS). FIG. 7 illustrates that CSI-RSs for eight antenna ports are allocated by FDM. The pattern of CSI-RS has been illustrated for eight antenna ports for wideband, but as mentioned above, it can be multiplexed by FDM or Code Division Multiplexing (CDM) or FDM / CDM scheme. Depending on the maximum number of supported antenna ports or the system environment, the CSI-RS pattern may have a different pattern from that of the CSI-RS pattern of FIG. 7. An example of an indication filed for CSI-RS is shown in Table 1 below. Table 1 below shows an indication field of downlink control information for CSI-RS.

(RRC signaling or DCI) Indication field	index	Descriptions
CSI-RS time domain indication field (in DCI)-1 bit	0	No CSI-RS region in xPDSCH Zone
	One	CSI-RS region exists in xPDSCH Zone
Number (#) of antenna ports of CSI-RS indication field (in RRC Signaling or DCI)-N bits	0	1 port
	One	2 ports
	2	4 ports
	3	8 ports
	?	?
	2 N -1	4 N ports
CSI-RS freq. domain indication field (in RRC Signaling or DCI)-M bits	0	PRB index: 0 to 4
	2	PRB index: 5 to 8
	3	PRB index: 9 to 12
	?	?
	2 M -1	PRB index: 4 * 2 M -4 to 4 * 2 M -1
CSI-RS measurement indication field (in RRC Signaling or DCI)-L bits	0	PRB index: 0 to 4
	2	PRB index: 5 to 8
	3	PRB index: 9 to 12
	?	?
	2 M -1	PRB index: 4 * 2 M -4 to 4 * 2 M -1

Referring to Table 1, the UE may recognize whether to allocate CSI-RS resources in the xPDSCH through the RRC signaling of the base station or the CSI-RS time domain indication field (eg, 1 bit) of the DCI. Can be. Through this, when the UE that does not receive the CSI-RS receives downlink data through the corresponding xPDSCH zone, data decoding should be performed in an area excluding the CSI-RS resource area. In this case, when the base station transmits DCI for downlink data transmission, the base station needs to control TBS scheduling considering the CSI-RS resource zone and a modulation and coding scheme (MCS) according thereto.

In the above-described subband CSI-RS, the size of the subband may vary. For example, assuming that the total size of the wideband is 100 physical resource blocks (PRBs), the size of the subband may vary from 4 PRBs, 10 PRBs, 20 PRBs, 50 PRBs, 100 PRBs, and the like.

The base station may indicate the allocation size and / or location (eg, PRB index of the subband) of the CSI-RS zone through the "CSI-RS frequency domain indication field" through the RRC signaling or DCI. The UE may recognize the location in the frequency domain of the CSI-RS through the “CSI-RS frequency domain indication field”.

In addition, the base station may transmit a "CSI-RS measurement indication field" to the terminal through RRC signaling or DCI. The “CSI-RS measurement indication field” indicates the measurement of the CSI-RS and may also indicate the frequency location (eg, PRB index information) of the CSI-RS to be measured at the same time. The terminal may measure the CSI-RS in the indicated region based on the “CSI-RS measurement indication field”.

All fields of Table 1 described above are described based on an indication of a subframe in which the field information is received, but are predefined or indicated in the system in consideration of the DCI decoding processing time of the UE. It may be an indication of a subframe after the subframe in which the DCI is received by the offset value. For example, if the offset value is α, the base station transmits a DCI including an indication field before α subframes. Then, a CSI-RS zone is generated in a corresponding subframe after α subframes from the subframe in which the DCI is received. The UE may receive the CSI-RS in the CSI-RS region allocated to the corresponding subframe based on the offset value. The offset value can also be applied to all the fields mentioned below.

UE behavior may be changed as follows by the above-described CSI-RS design scheme.

(1) The UE, which has undergone the initial access step, recognizes the indication information on the CSI-RS through the RRC signaling step. The UE decodes the received “the number of antenna ports of CSI-RS indication field”, “CSI-RS frequency domain indication field” and “CSI-RS measurement indication field” to obtain respective index information. In contrast, when the fields are transmitted in the DCI, the terminal may receive index information in the DCI.

(2) Meanwhile, in the RRC Connected step, each UE decodes a DCI for itself in a downlink control zone (eg, xPDCCH zone) and recognizes indication information on the CSI-RS. The UE in the RRC_Connected state decodes “the number (#) of antenna ports of SRS indication field”, “CSI-RS frequency domain indication field” and “CSI-RS measurement indication field” indicated through the DCI format. Index information can be received. When the fields are transmitted through RRC signaling, the UE may have already received corresponding index information in RRC signaling.

(3) When the UE recognizes the CSI-RS information through the RRC signaling and / or DCI fields, the UE can measure the CSI-RS to generate channel state information and feed back to the base station.

When the CSI-RS time domain indication field indicates '0', the UE recognizes that there is no CSI-RS region in the xPDSCH zone and decodes only the data of the xPDSCH zone. If the CSI-RS time domain indication field indicates '1', the UE decodes the xPDSCH and then measures the CSI-RS in the area that the UE should measure in the CSI-RS region. Information about the measurement region may be indicated by the “the number of antenna ports of the CSI-RS indication field”, the “CSI-RS frequency domain indication field” and the “CSI-RS measurement indication field”.

(4) The UE performs the measurement based on the CSI-RS and uses the channel state information generated based on the measurement to determine an uplink control zone (eg, xPUCCH) or uplink data zone (eg, xPUSCH). It can feed back to the base station.

The above-described methods have been described as an example of a self-contained subframe structure, but may be applied to existing LTE or other communication systems. In addition, the above-described methods described the self-contained subframe structure for the stand-alone NR operation as an example, but may also be applied to the structure for the non-stand-alone NR operation. The above-described methods illustrate a case of a subframe configured in the order of DL control zone-Guard Period (GP)-UL control zone, but the present invention is not limited thereto and may be applied to other types of subframes capable of uplink transmission. The above-described methods are illustrated in the case of a subframe composed of seven symbols of a Short TTI type, but may also be applied to a subframe having a different number of symbols or a different size or number of downlink data zones, such as a general TTI or a Long TTI. Can be. Although various Indication files for CSI-RS have been illustrated in the above-described methods, they may be indicated by different values or different field names.

The embodiments described above are the components and features of the present invention are combined in a predetermined form. Each component or feature is to be considered optional unless stated otherwise. Each component or feature may be embodied in a form that is not combined with other components or features. It is also possible to combine some of the components and / or features to form an embodiment of the invention. The order of the operations described in the embodiments of the present invention may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment. It is obvious that the claims may be combined to form an embodiment by combining claims that do not have an explicit citation relationship in the claims or as new claims by post-application correction.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the essential features of the present invention. Accordingly, the above detailed description should not be construed as limiting in all aspects and should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention.

The method and apparatus for receiving the CSI-RS in the wireless communication system can be applied industrially in various wireless communication systems such as 3GPP LTE / LTE-A, 5G system.

Claims (15)

1. In a method for receiving a channel state information reference signal (CSI-RS) in a terminal in a wireless communication system,

   Receiving control information including information indicating whether a resource for the CSI-RS is allocated to a specific subframe; And

   When the data zone of the specific subframe is allocated to a downlink data zone and the control information indicates that resources for the CSI-RS are allocated to the specific subframe, the CSI-RS is downlinked based on the control information. Receiving in the link control zone.
2. The method of claim 1,

   The CSI-RS is received in the last symbol of the downlink control zone.
3. The method of claim 1,

   The control information is received in the specific subframe.
4. The method of claim 1,

   The resource for the CSI-RS is allocated to the downlink data zone of the specific subframe.
5. The method of claim 1,

   The control information further includes information indicating the number of antenna ports for the CSI-RS.
6. The method of claim 1,

   The control information further includes information on the location of the resource to which the CSI-RS is allocated.
7. The method of claim 6,

   The information on the location of the resource to which the CSI-RS is allocated is location information in the frequency domain.
8. The method of claim 1,

   And receiving the CSI-RS in a downlink control zone of the specific subframe.
9. The method of claim 1,

   And receiving the CSI-RS in a subsequent subframe corresponding to the offset value in the specific subframe based on a predefined or indicated offset value.
10. The method of claim 1,

    Performing channel measurement based on the CSI-RS; And

    And transmitting the measurement result according to the channel measurement through an uplink control zone or an uplink data zone.
11. A terminal for receiving a channel state information reference signal (CSI-RS) in a wireless communication system,

    receiving set; And

    Include processors,

    The processor,

    Control the receiver to receive control information including information indicating whether a resource for the CSI-RS is allocated to a specific subframe,

    When the data zone of the specific subframe is allocated to a downlink data zone and the control information indicates that a resource for the CSI-RS is allocated to the specific subframe, the receiver determines that the CSI- is based on the control information. A terminal for controlling to receive an RS in a downlink control zone.
12. The method of claim 11,

    And the processor controls the receiver to receive the CSI-RS in the last symbol of the downlink control zone.
13. The method of claim 11,

    And the processor controls the receiver to receive the control information in the specific subframe.
14. The method of claim 11,

    The resource for the CSI-RS is allocated to the downlink data zone of the specific subframe.
15. The method of claim 11,

    Further includes a transmitter,

    The processor performs channel measurement based on the CSI-RS, and controls the transmitter to transmit a measurement result according to the channel measurement through an uplink control zone or an uplink data zone.

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