WO2017213340A1 - Method for receiving information related to reference signal in wireless communication system, and terminal therefor - Google Patents

Abstract

A method for receiving information related to a reference signal by a terminal in a wireless communication system may comprise the steps of: receiving control information including information indicating whether a resource for a sounding reference signal (SRS) has been allocated to a specific subframe; and when the control information indicates that a resource for the SRS has been allocated to the specific subframe, transmitting the SRS in the specific subframe, wherein the SRS is transmitted in consideration of whether a data zone of the specific subframe is allocated as a downlink data zone or an uplink data zone.

Description

Method for receiving information related to a reference signal in a wireless communication system and a terminal for the same

The present invention relates to wireless communication, and more particularly, to a method for receiving information related to a reference signal in a wireless communication system and a terminal for the same.

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, it is required to design details related to SRS and CSI-RS transmission.

An object of the present invention is to provide a method for a terminal to receive information related to a reference signal in a wireless communication system according to an embodiment of the present invention.

An object of the present invention is to provide a method for a terminal to receive information related to a reference signal in a wireless communication system according to another embodiment of the present invention.

Another object of the present invention is to provide a terminal for receiving information related to a reference signal in a wireless communication system according to an embodiment of the present invention.

Another object of the present invention is to provide a terminal for receiving information related to a reference signal in a wireless communication system according to another embodiment of the present invention.

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 information related to a reference signal by a terminal in a wireless communication system according to an embodiment of the present invention provides a sounding reference signal (SRS) for a specific subframe. Receiving control information including information indicating whether a resource is allocated; And when the control information indicates that the resource for the SRS is allocated to the specific subframe, transmitting the SRS in the specific subframe, wherein the data zone of the specific subframe is allocated to a downlink data zone. The SRS may be transmitted in consideration of whether the information is allocated to the uplink data zone.

When the data zone is allocated to an uplink data zone, the SRS may be transmitted in the last symbol of the uplink data zone. When the data zone is allocated as a downlink data zone, the SRS may be transmitted in the first symbol of the uplink control zone.

When the control information indicates that the resource for the SRS is allocated to the specific subframe, the control information may further include information indicating a frequency domain for transmitting the SRS. When the control information indicates that the resource for the SRS is allocated to the specific subframe, the control information may further include information indicating the number of antenna ports for transmitting the SRS.

The specific subframe may include a downlink control zone, the data zone and an uplink control zone, and may be allocated to the specific subframe in the order of the downlink control zone, the data zone, and the uplink control zone. The control information may be received in the specific subframe.

In order to achieve the above technical problem, a method for a terminal receiving information related to a reference signal in a wireless communication system according to another embodiment of the present invention, a method for receiving information related to a reference signal from the terminal in a wireless communication system Receiving control information including information indicating whether a resource for a channel state information reference signal (CSI-RS) is allocated to a specific subframe; And receiving the CSI-RS in a downlink control zone of the specific subframe when the control information indicates that a resource for the CSI-RS is allocated to the specific subframe.

The CSI-RS may be received in the last symbol of the downlink control zone of the specific subframe. 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. The control information may be received in the specific subframe.

In order to achieve the above technical problem, a terminal for receiving information related to a reference signal in a wireless communication system according to an embodiment of the present invention, a terminal for receiving information related to a reference signal in a wireless communication system, receiving set; transmitter; And a processor, wherein the processor controls the receiver to receive control information including information indicating whether a resource for a sounding reference signal (SRS) is allocated to a specific subframe, The processor controls the transmitter to transmit the SRS in the specific subframe when the control information indicates that the resource for the SRS is allocated to the specific subframe. The transmitter may be controlled to transmit the SRS in consideration of whether the information is allocated to a downlink data zone or an uplink data zone.

When the data zone is allocated to an uplink data zone, the processor may control the transmitter to transmit the SRS in the last symbol of the uplink data zone. When the data zone is allocated to an uplink data zone, the processor may control the transmitter to transmit the SRS in the first symbol of an uplink control zone.

In order to achieve the above technical problem, a terminal for receiving information related to a reference signal in a wireless communication system according to another embodiment of the present invention, the terminal for receiving information related to the reference signal in a wireless communication system A receiver; And a processor, wherein the processor includes control information including information indicating whether the receiver allocates a resource for a channel state information reference signal (CSI-RS) to a specific subframe; Receive the CSI-RS in the downlink control zone of the specific subframe when the control information indicates that the resource for the CSI-RS is allocated to the specific subframe. Can be controlled.

The processor may control the receiver to receive the CSI-RS in the last symbol of a downlink control zone of the specific subframe. The terminal further includes a transmitter, wherein the processor is configured to perform channel measurement based on the CSI-RS, wherein the processor transmits a measurement result according to the channel measurement by an uplink control zone or uplink data. It can be controlled to transmit through the zone.

The SRS transmission scheme according to an embodiment of the present invention provides an efficient uplink channel state measurement scheme of a self-contained scheme 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 the allocation of the SRS of the self-contained subframe structure.

8 is a diagram illustrating the allocation of the SRS in the uplink control zone of the self-contained subframe structure (when the data zone is allocated to the downlink data zone).

9 is a diagram illustrating the allocation of the SRS in the uplink control zone of the self-contained subframe structure (when the data zone is allocated to the uplink data zone).

FIG. 10 is a diagram illustrating allocation of CSI-RS in a downlink control zone of a self-contained subframe structure on a resource grid (a case in which a data zone is allocated to a downlink data zone).

11 is a diagram illustrating the allocation of the CSI-RS in the downlink control zone of the self-contained subframe structure (case where the data zone is allocated to the uplink data zone).

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 Sounding Reference Symbol or Sounding Reference Signal (SRS) 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 uplink channel state. A reference signal for channel status measurement is not defined.

The present invention proposes a self-contained subframe structure described in FIG. 5 and an SRS transmission method of a new frame structure for a 5G TDD system. In addition, the present invention can be equally applied to an adaptive / self-contained frame structure. The present invention also proposes a CSI-RS (Channel State Information-Reference Signal) in the entire subframe 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.

Example 1 : Sounding Reference Symbol in the Data Zone ( SRS )

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

Referring to FIG. 6, a subband SRS is transmitted at a fifth symbol of the subframe Subframe # M (or a sixth symbol position including a guard period). The details of the SRS design method are as follows.

(1) When the data zone is allocated to the uplink data zone in the self-contained subframe, the UE transmits the SRS in the last OFDM symbol of the uplink data channel (eg, xPUSCH) zone.

In this case, in order not to affect the data decoding as much as possible for low latency, the UE is multiplexed in a frequency division multiplexing (FDM) method and a code division multiplexing (CDM) comb method 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 an SRS zone that cannot assist in decoding uplink data of the frame at the rear of the data zone. In addition, if data decoding is possible during the SRS zone and the uplink control channel (eg, xPUCCH) zone for SRS transmission and ACK / NACK encoding is possible, the downlink control channel (eg, xPDCCH) of the next subframe is possible. In this zone, fast ACK / NACK transmission may be possible.

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

In the case of periodic SRS, the period is indicated by the base station to the terminal by common control information (for example, Master Information Block (MIB) or System Information Block (SIB), Radio Resource Control (RRC) signaling or DCI). It can be defined or defined as the system's default assignment and can operate without instructions.

For aperiodic SRS, the base station schedules aperiodic SRS transmission with DCI. The base station may indicate to the UE whether or not the corresponding subframe is a subframe transmitting SRS in DCI (eg, DCI 1 bit) in the corresponding subframe. The number of antenna ports of the aperiodic SRS may be defined by the base station instructing the terminal through additional bits of the RRC signaling or the DCI or as the default assignment of the system and may not be indicated. Through the aperiodic SRS, a request for the aperiodic SRS to the terminal without waiting for the periodic SRS, to quickly obtain the uplink scheduling information, it is possible to enable a low-latency uplink service.

(3) The terminal transmits the SRS to the subband or wideband in the frequency domain.

The terminal may transmit the SRS over the entire wideband of the SRS or transmit the SRS only in some subbands by the base station scheduling. For fine channeling for uplink channel state measurement and uplink synchronization of the terminal, the base station may allocate a terminal-specific SRS region to the SRS zone. In order to secure the scheduling gain for the wideband, the base station may allocate a wideband based SRS. In this case, the base station may instruct the terminal through additional bits of the RRC signaling or the DCI or define a default assignment of the system to not transmit a special indication. It may be. The BS may instruct the UE to allocate subband based SRS through RRC signaling or additional bits of DCI to secure resources of an uplink data channel (eg, xPUSCH). In addition, the base station may instruct the UE to subband-based SRS allocation through the additional bits of the RRC signaling or DCI to solve the power consumption or power shortage problem of the terminal. In order to measure only a channel for a specific band based on long term channel gain information, the base station may instruct the terminal through subband-based SRS allocation through RRC signaling or additional bits of DCI. 7 illustrates on the resource grid the allocation of the above-described SRS.

7 is a diagram illustrating the allocation of the SRS of the self-contained subframe structure.

Referring to FIG. 7, subframe #L illustrates a subframe in which an SRS is not transmitted, and subframe #M and subframe #N illustrate a subframe in which an SRS is transmitted. Here, the subband SRS is transmitted in Subframe #M of FIG. 7, and the wideband SRS is transmitted in Subframe #N. Although the antenna port for the SRS is not shown, it is assumed that the antenna port is allocated in the CDM scheme in the region where the SRS is allocated. In addition, it is assumed that the number of resource elements (RE) of the subband SRS or the wideband SRS is sufficiently larger than the maximum number of antenna supports. Table 1 below illustrates an indication field of downlink control information for SRS.

(DCI or RRC signaling) Indication field	index	Descriptions
SRS time domain indication field (in DCI)-1 bit	0	No SRS region in xPUSCH Zone
	One	SRS region exists in xPUSCH Zone
The number of antenna ports of SRS 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
SRS frequency 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

Referring to Table 1, the UE receives 1 bit of the SRS time domain indication field of the RRC signaling or the DCI of the base station, and thus, an uplink data zone or an uplink data channel (eg, xPUSCH) zone. It is possible to recognize whether or not SRS resource allocation within. Through this, when a UE that does not transmit SRS transmits uplink data through the corresponding xPUSCH zone, a transport block size (TBS) must be defined in a region excluding the SRS resource region and symbol mapping is performed. In this case, when the base station transmits a grant for uplink data transmission, the base station needs TBS scheduling considering the SRS resource zone and modulation and coding scheme (MCS) control according thereto.

In the subband SRS mentioned above, 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 indicates the size and / or location (eg, PRB index of the subband) of the subband for subband SRS transmission through the SRS freq.domain indication field of the RRC signaling or the DCI. Can be.

As described above, in order to secure resources of an uplink data channel (for example, xPUSCH), a base station allocates subband SRS to solve a power consumption or power shortage problem of a terminal, or only for channel measurement for a specific band. can do. The UE may recognize whether the SRS resource is allocated in the corresponding band through the SRS frequency domain indication field. Through this, when a UE that does not transmit SRS transmits uplink data in frequency resources allocated to the SRS of the corresponding xPUSCH zone, TBS must be defined and symbol mapping is performed in an area excluding the SRS resource zone. Here, when the base station transmits a grant for uplink data transmission, the base station needs to perform TBS scheduling considering the SRS resource zone and MCS control according thereto.

All fields mentioned in Table 1 are described based on an indication of a corresponding subframe in which the fields are transmitted, but in consideration of the decoding processing time of DCI, fixedly by an offset value predefined in the system It may be indicated in advance. For example, if the offset value is α, the indication field may be transmitted through DCI before α subframes. Then, the UE can recognize that the SRS zone is allocated to the subframes corresponding to the α subframes after the subframes receiving the DCI.

In addition, the base station may indicate the number of antenna ports to the terminal through the number indication field of the SRS antenna ports.

In addition, the base station may indicate by transforming the SRS Time-domain Indication filed shown in Table 1 to the RS time domain indication field shown in Table 2. The RS time domain indication field may indicate by tying the CSI-RS region and the SRS region with the data zone of the subframe. The data zone of each subframe may be a downlink data zone or an uplink data zone. When the data zone of each subframe is allocated to the downlink data zone, the time-domain indication filed for the RS is determined for the CSI-RS. When the uplink data zone is assigned, the time-domain indication filed for the RS may be an indication field for the SRS. Through this, the base station can indicate whether the CSI-RS region allocation in the downlink data zone and the SRS region allocation in the uplink data zone with one indication filed. The following table and an example of the RS time domain indication field.

(RRC signaling or DCI) Indication field	index	Data Zone	Descriptions
RS time domain indication field (in DCI)-1 bit	0	xPDSCH	No CSI-RS region in Data Zone
		xPUSCH	No SRS Regions in the Data Zone
	One	xPDSCH	CSI-RS region exists in the data zone
		xPUSCH	SRS region exists within the data zone

Through the above indication method, the base station may perform indication on the CSI-RS and the SRS only with 1 bit of RS time domain indication field in DCI. Table 2 has the advantage of reducing the DCI information and optimizing the container of the control channel.

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

(1) The terminal, which has undergone the initial access step, recognizes the indication information on the SRS through the RRC signaling step. The UE may decode “the number of antenna ports of SRS indication field” and “SRS frequency domain indication field” indicated through RRC signaling 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 its DCI in a downlink control channel (eg, xPDCCH) zone to recognize indication information about the SRS. The UE in the RRC_Connected state decodes the SRS time domain indication field (or RS time domain indication field) indicated through the DCI format to determine whether there is an SRS region for SRS transmission in an uplink data zone (eg, xPUSCH Zone). It can be seen. In addition, the UE in the RRC_Connected state may receive the corresponding index information by decoding the “the number of antenna ports of SRS indication field” and the “SRS frequency domain indication field” indicated through the DCI format. When the fields are transmitted through RRC signaling, the UE may have already received corresponding index information in RRC signaling.

(3) If the UE recognizes the SRS information through the RRC signaling and / or DCI fields, it can transmit the SRS through the indicated UE-specific SRS region. If the SRS (or RS) time domain indication field is 0, the UE transmits only xPUSCH. If the SRS (or RS) time domain indication field is 1, after transmitting the xPUSCH, the UE transmits the SRS through the region in which the indicated SRS should be transmitted among the SRS regions of the last symbol. The area to which the SRS should be transmitted may be determined according to index information of the “the number of antenna ports of the SRS indication field” and the “SRS frequency domain indication field”.

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-UL data zone-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 SRS have been illustrated in the above-described methods, they may be indicated by different values or different field names.

Example  2: in the control zone SRS  Sounding Reference Signal ( SRS ) in Control Zone)

Details of the SRS design scheme in the control zone are described below.

(1) The UE transmits the SRS in the first OFDM symbol of the uplink control channel (eg, xPUCCH) zone.

Due to the asymmetric nature of downlink and uplink traffic, a data zone may not be allocated as an uplink (usually because more downlink traffic is more than uplink traffic). In case, the UE can transmit the SRS through the xPUCCH zone. In this case, the terminal may transmit the SRS periodically or aperiodically.

When the aperiodic SRS request is transmitted through the downlink control zone, a quick SRS request is possible without configuring the aperiodic data zone of the data zone. That is, a periodic SRS is allocated to the data zone, and for a quick SRS request, an aperiodic SRS may be requested through the downlink control zone. In this case, the base station needs to consider the aperiodic SRS zone when transmitting the DCI through the downlink control zone.

On the contrary, if the aperiodic SRS request is transmitted through the downlink data zone, a fast SRS request is possible without configuring the aperiodic control zone of the downlink control zone. That is, a periodic SRS transmission request is allocated through the downlink control zone, and for a fast SRS request, an aperiodic SRS can be requested through the downlink data zone. In this case, it is necessary to consider the aperiodic SRS Zone when configuring scheduling and grant for the data zone.

In case that the UE performs fast ACK / NACK transmission on downlink data received in the data zone based on the self-contained frame structure characteristic, to guarantee the data decoding time (or to guarantee the ACK / NACK encoding time). The base station may achieve fast ACK / NACK performance by allocating an SRS region to the first symbol of the xPUCCH zone and transmitting the xPUCCH to the next symbol.

The xPUCCH zone is multiplexed in the first OFDM symbol in a comb manner of FDM and CDM manners.

Even when the data zone is allocated to the uplink data zone, the UE may transmit the SRS in the xPUCCH zone. In order to maintain compatibility with the case where the data zone is allocated for downlink, the UE may transmit an SRS to the first symbol of the xPUCCH zone. Unlike the case where the data zone is allocated in the downlink, the terminal may transmit the SRS to the last symbol of the xPUCCH zone to secure the UL-DL switching time of the terminal transmitting the xPUCCH.

(2) The UE may transmit the SRS periodically or aperiodically in the time domain, and in particular, the SRS transmission may be indicated through the DCI.

In the case of periodic SRS, the period is indicated by the base station to the terminal by common control information (for example, Master Information Block (MIB) or System Information Block (SIB), Radio Resource Control (RRC) signaling or DCI). It can be defined or defined as the system's default assignment and can operate without instructions.

For aperiodic SRS, the base station schedules aperiodic SRS transmission with DCI. The base station may indicate to the UE whether or not the corresponding subframe is a subframe transmitting SRS in DCI (eg, DCI 1 bit) in the corresponding subframe. The number of antenna ports of the aperiodic SRS may be defined by the base station instructing the terminal through additional bits of the RRC signaling or the DCI or as the default assignment of the system and may not be indicated. Through the aperiodic SRS, a request for the aperiodic SRS to the terminal without waiting for the periodic SRS, to quickly obtain the uplink scheduling information, it is possible to enable a low-latency uplink service.

(3) The terminal transmits the SRS to the subband or wideband in the frequency domain.

The terminal may transmit the SRS over the entire wideband of the SRS or transmit the SRS only in some subbands by the base station scheduling. For fine channeling for uplink channel state measurement and uplink synchronization of the terminal, the base station may allocate a terminal-specific SRS region to the SRS zone. In order to secure the scheduling gain for the wideband, the base station may allocate a wideband based SRS. In this case, the base station may instruct the terminal through additional bits of the RRC signaling or the DCI or define a default assignment of the system to not transmit a special indication. It may be. The base station may instruct the UE to allocate subband based SRS through RRC signaling or additional bits of DCI to secure an uplink data channel (eg, xPUSCH). In addition, the base station may instruct the terminal to subband-based SRS allocation through the additional bits of the RRC signaling or DCI to solve the power consumption or power shortage problem of the terminal. Even for channel measurement only for a specific band based on long term channel gain information, the base station may instruct the terminal to allocate subband based SRS to the terminal through additional bits of RRC signaling or DCI. 8 illustrates the SRS region allocation according to the second embodiment on a resource grid.

8 is a diagram illustrating the allocation of the SRS in the uplink control zone of the self-contained subframe structure (when the data zone is allocated to the downlink data zone).

Referring to FIG. 8, subframe #K and subframe #L represent subframes in which SRS is not transmitted, and subframe #M and subframe #N represent subframes in which SRS is transmitted. In subframe #K, the xPUCCH zone consists of one symbol. In subframe #L, the xPUCCH zone consists of two symbols. Here, in FIG. 8, the UE may transmit a subband SRS in subframe #M and a wideband SRS in subframe #N. In FIG. 8, the data zone is configured as a downlink data zone. In order to guarantee downlink data decoding time or ACK / NACK encoding time when performing fast ACK / NACK on downlink data, the base station allocates an SRS region to the first symbol of the xPUCCH zone, and uplink control information (xPUCCH) is SRS. Fast ACK / NACK can be achieved by allowing reception on the next symbol of transmission.

Although the antenna port for SRS transmission is not shown in FIG. 8, it is assumed that an antenna port is allocated in a CDM manner in an area where SRS is allocated. In addition, it is assumed that the number of REs of the subband SRS or the wideband SRS is larger than the maximum number of antenna supports.

9 is a diagram illustrating the allocation of the SRS in the uplink control zone of the self-contained subframe structure (when the data zone is allocated to the uplink data zone).

Referring to FIG. 9, subframe #K and subframe #L illustrate a subframe in which SRS is not transmitted, and subframe #M and subframe #N illustrate a subframe in which SRS is transmitted. Here, subframe #K of FIG. 9 illustrates an xPUCCH zone of one symbol, and subframe #L illustrates an xPUCCH zone of two symbols. Here, subframe #M of FIG. 9 illustrates a subband SRS, and subframe #N illustrates a wideband SRS. Although the antenna port for the SRS is not illustrated, it is assumed that the antenna port is allocated in the CDM manner in the region where the SRS is allocated. And it is assumed that the number of resource elements (RE) of the subband or wideband SRS is sufficiently larger than the maximum number of antenna supports.

The Indication filed example for SRS is the same as in Embodiment 1, and there is a DCI 1 bit addition as to whether or not the SRS is present in xPUCCH.

Indication field	index	Descriptions
SRS time domain indication field in xPUCCH (in DCI)-1 bit	0	No SRS region in xPUCCH Zone
	One	SRS region exists in xPUCCH Zone

Embodiment 2 described above may coexist with Embodiment 1 in one system, and may alternatively operate in only one embodiment.

Example  3: CSI- in the control zone RS  Channel State Information Reference Signal (CSI- RS ) in Control Zone)

As in the second embodiment, the CSI-RS may exist in the control zone. Detailed design method and transmission method of CSI-RS are as follows.

(1) CSI-RS may be transmitted in the last OFDM symbol of a downlink control zone (eg, xPDCCH zone).

Even when the data zone is not allocated to the downlink data zone, the UE may perform measurement on the CSI-RS. In this case, the UE may transmit the CSI-RS through the xPDCCH zone. The terminal may transmit a periodic or aperiodic CSI-RS. When the aperiodic CSI-RS is transmitted through the control zone, fast CSI-RS transmission is possible without configuring the aperiodic data zone of the data zone. That is, the periodic CSI-RS may be transmitted through the data zone, and when the fast channel measurement is required, the aperiodic CSI-RS may be transmitted through the control zone. In this case, when the DCI transmission through the control zone, it is necessary to consider the aperiodic CSI-RS zone. On the contrary, if the aperiodic CSI-RS is transmitted through the data zone, a fast channel measurement request is possible without configuring the aperiodic control zone of the control zone. That is, the periodic CSI-RS is transmitted through the second zone, and when the fast channel measurement is required, the aperiodic CSI-RS may be transmitted through the data zone. In this case, when scheduling for the data zone, it is necessary to consider the aperiodic CSI-RS zone.

In order to guarantee the decoding time for the DCI of the control zone, the base station may secure or allocate the CSI-RS region to the last symbol of the xPDCCH zone.

The last OFDM symbol of the xPDCCH zone may be multiplexed in FDM and Frequency domain CDM manner.

The CSI-RS may be transmitted in the xPDCCH zone even when the data zone is allocated to the downlink data zone. Even when the data zone is allocated to the uplink data zone, the base station may transmit the CSI-RS in the last symbol of the xPDCCH zone to ensure the decoding time for the DCI of the control zone.

(2) The CSI-RS is transmitted periodically or aperiodically in the Time Domain, and the base station can instruct the allocation and transmission of the CSI-RS through the DCI.

In the case of the periodic CSI-RS, the period is a common control information (Common Control Information) (eg, MIB or Master Information Block (SIB) or System Information Block (SIB), RRC (Radio Resource Control) signaling or the terminal is a terminal 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. Through the aperiodic CSI-RS, a request for the aperiodic CSI-RS to the terminal without waiting for the periodic CSI-RS, to obtain the uplink scheduling information quickly, it is possible to enable the low-latency uplink service.

(3) CSI-RS is transmitted in Subband or Wideband in Frequency Domain.

The base station may transmit the CSI-RS in the entire wideband or may transmit the CSI-RS in some subbands. For fine channeling for uplink channel state measurement and uplink synchronization of the terminal, the base station may allocate the terminal-specific CSI-RS region to the CSI-RS zone. In order to secure the scheduling gain for the wideband, the base station may allocate a wideband based CSI-RS, and in this case, indicate the terminal through RRC signaling or additional bits of the DCI or define a default assignment of the system to convey a special indication. You may not. The base station may instruct the UE to allocate subband based CSI-RS through RRC signaling or additional bits of DCI to secure an uplink data channel (eg, xPUSCH). In addition, the base station may instruct the UE to assign subband-based CSI-RS through additional bits of RRC signaling or DCI to solve a problem of power consumption or power shortage of the terminal. Even for channel measurement for a specific band based on long term channel gain information, the base station may instruct the terminal through subband-based CSI-RS allocation through RRC signaling or additional bits of DCI. .

(4) The UE can measure the entire wideband of the CSI-RS or only some subbands by base station scheduling.

(5) The UE may transmit feedback information through the uplink control zone (xPUCCH) or uplink data zone (xPUSCH) as measurement information that is a result of measuring the CSI-RS.

FIG. 10 is a diagram illustrating allocation of CSI-RS in a downlink control zone of a self-contained subframe structure on a resource grid (a case in which a data zone is allocated to a downlink data zone).

Referring to FIG. 10, subframe #L and subframe #M are illustrated as subframes in which CSI-RSs are not transmitted, and subframe #N is shown in subframes in which CSI-RSs are transmitted. In addition, the data zone is illustrated as being allocated a downlink data zone (xPDSCH zone). In order to guarantee the decoding time for the DCI of the control zone, the base station may secure or allocate a CSI-RS region to the last symbol of the xPDCCH zone. In the CSI-RS illustrated in FIG. 9, numerals 1 to 8 represent CSI-RSs for each antenna port, and are allocated in FDM manner for eight antenna ports. The pattern of CSI-RS has been illustrated for eight antenna ports for wideband, but as mentioned above, it can be multiplexed in FDM or CDM or FDM / CDM manner, and the maximum number of antenna ports that can be supported varies according to different system environments. It can have a pattern.

11 is a diagram illustrating the allocation of the CSI-RS in the downlink control zone of the self-contained subframe structure (case where the data zone is allocated to the uplink data zone).

Referring to FIG. 11, subframe #L and subframe #M are illustrated as subframes in which CSI-RSs are not transmitted in which CSI-RSs are not transmitted, and subframe #N in subframes in which CSI-RSs are transmitted. In addition, the data zone is exemplified as being allocated to an uplink data zone (xPUSCH zone). In order to guarantee the decoding time for the DCI of the control zone, the base station may secure or allocate a CSI-RS region to the last symbol of the xPDCCH zone. In the CSI-RS illustrated in FIG. 9, numerals 1 to 8 denote CSI-RSs for respective antenna ports, and are allocated in FDM manner for eight antenna ports. The pattern of CSI-RS has been illustrated for eight antenna ports for wideband, but as mentioned above, it can be multiplexed in FDM or CDM or FDM / CDM manner, and the maximum number of antenna ports that can be supported varies according to different system environments. It can have a pattern.

An example of an indication filed for CSI-RS is the same as that of Embodiment 1, and a DCI 1 bit for whether CSI-RS is present in xPDCCH may be added as shown in Table 4.

Indication field	index	Descriptions
CSI-RS time domain indication field in xPDCCH (in DCI)-1 bit	0	No CSI-RS region in xPDCCH Zone
	One	CSI-RS region exists in xPDCCH Zone

Embodiment 3 described above may coexist with Embodiment 1 in one system, and may optionally operate in only one embodiment.

The SRS / CSI-RS transmission method according to the embodiment described above provides an uplink / downlink channel state measurement method of an efficient self-contained frame structure in stand-alone NR. As described in the embodiment, the SRS may be multiplexed with xPUSCH or xPUCCH and the CSI-RS may be multiplexed with xPDSCH and xPDCCH. In addition, when a CSI-RS is transmitted in a subframe in which xPBCH is transmitted, it may also be multiplexed with xPBCH / PSS / SSS. Here, the multiplexing method has been described in the FDM manner, but may also be multiplexed in the TDM or CDM manner.

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.

A method for receiving information related to a reference signal in a wireless communication system and a terminal for the same can be applied industrially in various wireless communication systems such as 3GPP LTE / LTE-A, 5G system.

Claims (17)

1. In a method for receiving information related to a reference signal by a terminal in a wireless communication system,

   Receiving control information including information indicating whether a resource for a sounding reference signal (SRS) is allocated to a specific subframe; And

   And transmitting the SRS in the specific subframe when the control information indicates that a resource for the SRS is allocated to the specific subframe.

   Transmitting the SRS in consideration of whether a data zone of the specific subframe is allocated to a downlink data zone or an uplink data zone.
2. The method of claim 1,

   And when the data zone is allocated to an uplink data zone, transmitting the SRS in the last symbol of the uplink data zone.
3. The method of claim 1,

   And when the data zone is allocated to a downlink data zone, transmitting the SRS in the first symbol of an uplink control zone.
4. The method of claim 1,

   And when the control information indicates that a resource for the SRS is allocated to the specific subframe, the control information further comprises information indicating a frequency domain for transmitting the SRS.
5. The method of claim 1,

   And if the control information indicates that the resource for the SRS is allocated to the specific subframe, further comprising information indicating the number of antenna ports for transmitting the SRS.
6. The method of claim 1,

   The specific subframe includes a downlink control zone, the data zone and an uplink control zone,

   And receiving information associated with a reference signal allocated to the specific subframe in the order of the downlink control zone, the data zone, and the uplink control zone.
7. The method of claim 1,

   And wherein the control information is received in the specific subframe.
8. In a method for receiving information related to a reference signal by a terminal in a wireless communication system,

   Receiving control information including information indicating whether a resource for a channel state information reference signal (CSI-RS) is allocated to a specific subframe; And

   Receiving the CSI-RS in a downlink control zone of the specific subframe when the control information indicates that a resource for the CSI-RS is allocated to the specific subframe. How to receive.
9. The method of claim 8,

   The CSI-RS receives information related to a reference signal, which is received in a last symbol of a downlink control zone of the specific subframe.
10. The method of claim 8,

    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. The method of claim 8,

    And wherein the control information is received in the specific subframe.
12. A terminal for receiving information related to a reference signal in a wireless communication system,

    receiving set;

    transmitter; And

    Include processors,

    The processor controls the receiver to receive control information including information indicating whether a resource for a sounding reference signal (SRS) is allocated to a specific subframe,

    The processor controls the transmitter to transmit the SRS in the specific subframe when the control information indicates that the resource for the SRS is allocated to the specific subframe.

    The processor controls the transmitter to transmit the SRS in consideration of whether a data zone of the specific subframe is allocated to a downlink data zone or an uplink data zone.
13. The method of claim 12,

    If the data zone is allocated to an uplink data zone, the processor controls the transmitter to transmit the SRS in the last symbol of the uplink data zone.
14. The method of claim 12,

    If the data zone is assigned to an uplink data zone, the processor controls the transmitter to transmit the SRS in the first symbol of an uplink control zone.
15. A terminal for receiving information related to a reference signal in a wireless communication system,

    receiving set; And

    Include processors,

    The processor controls the receiver to receive control information including information indicating whether a resource for a channel state information reference signal (CSI-RS) is allocated to a specific subframe,

    The processor controls the receiver to receive the CSI-RS in a downlink control zone of the specific subframe when the control information indicates that the resource for the CSI-RS is allocated to the specific subframe.
16. The method of claim 15,

    And the processor controls the receiver to receive the CSI-RS in the last symbol of a downlink control zone of the specific subframe.
17. The method of claim 15,

    Further includes a transmitter,

    The processor is configured to perform channel measurement based on the CSI-RS,

    The processor 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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