KR20200116026A - Method and apparatus for transmitting and receiving reference signal for sidelink channel state information acquisition - Google Patents

Abstract

Embodiments of the present invention relate to a method and apparatus for transmitting and receiving a reference signal for obtaining sidelink channel state information. According to an embodiment of the present invention, a method for transmitting a reference signal to obtain sidelink channel state information by a transmission terminal comprises the steps of: receiving activation information of channel state information (CSI) reporting; determining whether to transmit sidelink channel state information reference signal (SL CSI-RS) based on the activation information of the CSI reporting; and transmitting the SL CSI-RS to a reception terminal within resources allocated for physical sidelink shared channel (PSSCH) transmission.

Description

Reference signal transmission/reception method and device for obtaining sidelink channel status information {METHOD AND APPARATUS FOR TRANSMITTING AND RECEIVING REFERENCE SIGNAL FOR SIDELINK CHANNEL STATE INFORMATION ACQUISITION}

The present embodiments propose a method and apparatus for transmitting and receiving a reference signal in order to obtain sidelink channel state information in a next-generation radio access network (hereinafter referred to as "NR[New Radio]").

3GPP recently approved "Study on New Radio Access Technology", a study item for research on next-generation radio access technology (that is, 5G radio access technology), and based on this, RAN WG1 for each NR (New Radio) Designs for a frame structure, channel coding & modulation, waveform & multiple access scheme, etc. are in progress. NR is required to be designed to satisfy various QoS requirements required for each subdivided and detailed usage scenario as well as an improved data rate compared to LTE.

As representative usage scenarios of NR, eMBB (enhancement mobile broadband), mMTC (massive machine type communication), and URLLC (Ultra Reliable and Low Latency Communications) are defined, and a frame structure that is flexible compared to LTE in order to satisfy the needs of each usage scenario Design is required.

Each usage scenario has different requirements for data rates, latency, reliability, coverage, etc., so that the frequency bands constituting an arbitrary NR system are used. Based on different numerology (e.g., subcarrier spacing, subframe, TTI (Transmission Time Interval), etc.) as a method to efficiently satisfy the needs of each usage scenario There is a need for a method of efficiently multiplexing a radio resource unit of a device.

As part of this aspect, a design for transmitting a reference signal to a receiving terminal to acquire channel state information for a sidelink, that is, NR sidelink transmission, which is a wireless link between terminals for providing V2X service in NR. Becomes necessary.

Embodiments of the present disclosure may provide a specific method and apparatus capable of transmitting and receiving a reference signal between a transmitting terminal and a receiving terminal in order to obtain channel state information for sidelink transmission in NR.

In one aspect, in the present embodiments, in a method for a transmitting terminal to transmit a reference signal to obtain sidelink channel state information, receiving activation information of sidelink channel state information (CSI) reporting, CSI Determining whether to transmit a Sidelink Channel State Information Reference Signal (SL CSI-RS) based on the activation information of the reporting and allocating it to a Physical Sidelink Shared Channel (PSSCH) transmission Within the resource, it is possible to provide a method including the step of transmitting the SL CSI-RS to the receiving terminal.

In another aspect, in the present embodiments, in a method for a receiving terminal to receive a reference signal to obtain sidelink channel state information, CSI reporting within resources allocated for sidelink data channel (Physical Sidelink Shared Channel; PSSCH) transmission Receiving a sidelink channel state information reference signal (SL CSI-RS) from a transmitting terminal, for which transmission is determined based on activation information of, and CSI reporting based on the received SL CSI-RS It may provide a method comprising the step of performing.

In another aspect, in the present embodiments, in a transmitting terminal transmitting a reference signal to obtain sidelink channel state information, a receiving unit receiving activation information of sidelink channel state information (CSI) reporting, CSI reporting A control unit that determines whether to transmit a Sidelink Channel State Information Reference Signal (SL CSI-RS) based on the activation information of and is allocated to a sidelink data channel (Physical Sidelink Shared Channel; PSSCH) transmission. Within the resource, it is possible to provide a terminal including a transmitter for transmitting the SL CSI-RS to the receiving terminal.

In another aspect, the present embodiments provide a receiving terminal receiving a reference signal to obtain sidelink channel state information, within a resource allocated to a sidelink data channel (Physical Sidelink Shared Channel; PSSCH) transmission, of CSI reporting. CSI reporting based on a receiving unit for receiving a sidelink channel state information reference signal (SL CSI-RS) from a transmitting terminal and a received SL CSI-RS for which transmission is determined based on activation information A terminal including a transmitting unit to perform may be provided.

According to the present embodiments, it is possible to provide a method and apparatus for transmitting and receiving a reference signal between a transmitting terminal and a receiving terminal in order to obtain channel state information for sidelink transmission in NR.

1 is a diagram schematically illustrating a structure of an NR wireless communication system to which the present embodiment can be applied.
2 is a diagram for explaining a frame structure in an NR system to which this embodiment can be applied.
3 is a diagram illustrating a resource grid supported by a radio access technology to which the present embodiment can be applied.
4 is a diagram for explaining a bandwidth part supported by a wireless access technology to which the present embodiment can be applied.
5 is a diagram illustrating a synchronization signal block in a wireless access technology to which the present embodiment can be applied.
6 is a diagram for explaining a random access procedure in a radio access technology to which the present embodiment can be applied.
7 is a diagram for explaining CORESET.
8 is a diagram for explaining various scenarios for V2X communication.
FIG. 9 shows an example of UE1 and UE2 performing sidelink communication, and a sidelink resource pool that they use.
10 is a diagram for explaining a method of bundling and transmitting HARQ feedback information in V2X.
11 illustrates the type of a V2X transmission resource pool.
12 is a diagram showing an example of symbol level alignment among different SCSs in different SCSs to which the present embodiment can be applied.
13 is a diagram illustrating a conceptual example of a bandwidth part to which the present embodiment can be applied.
14 is a diagram illustrating a procedure for a transmitting terminal to transmit a sidelink channel state information reference signal (SL CSI-RS) to a receiving terminal according to an embodiment.
15 is a diagram illustrating a procedure for a receiving terminal to receive an SL CSI-RS from a transmitting terminal according to an embodiment.
16 is a diagram showing a configuration of a transmitting terminal according to another embodiment.
17 is a diagram showing a configuration of a receiving terminal according to another embodiment.

Hereinafter, some embodiments of the present disclosure will be described in detail with reference to exemplary drawings. In adding reference numerals to elements of each drawing, the same elements may have the same numerals as possible even if they are indicated on different drawings. In addition, in describing the embodiments, when it is determined that a detailed description of a related known configuration or function may obscure the gist of the present technical idea, the detailed description may be omitted. When "include", "have", "consists of" and the like mentioned in the present specification are used, other parts may be added unless "only" is used. In the case of expressing the constituent elements in the singular, the case including plural may be included unless there is a specific explicit description.

In addition, in describing the constituent elements of the present disclosure, terms such as first, second, A, B, (a) and (b) may be used. These terms are only for distinguishing the component from other components, and the nature, order, order, or number of the component is not limited by the term.

In the description of the positional relationship of the components, when two or more components are described as being "connected", "coupled" or "connected", the two or more components are directly "connected", "coupled" or "connected" It should be understood that "may be, but two or more components and other components may be further "interposed" to be "connected", "coupled" or "connected". Here, the other components may be included in one or more of two or more components "connected", "coupled" or "connected" to each other.

In the description of the temporal flow relationship related to the components, the operation method or the manufacturing method, for example, the temporal predecessor relationship such as "after", "after", "after", "before", etc. Alternatively, a case where a flow forward and backward relationship is described may also include a case that is not continuous unless "direct" or "direct" is used.

On the other hand, when a numerical value for a component or its corresponding information (e.g., level, etc.) is mentioned, the numerical value or its corresponding information is related to various factors (e.g., process factors, internal or external impacts, etc.) It can be interpreted as including an error range that may be caused by noise, etc.).

The wireless communication system in the present specification refers to a system for providing various communication services such as voice and data packets using radio resources, and may include a terminal, a base station, or a core network.

The embodiments disclosed below can be applied to a wireless communication system using various wireless access technologies. For example, the present embodiments include code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA). Alternatively, it may be applied to various wireless access technologies such as non-orthogonal multiple access (NOMA). In addition, the wireless access technology may mean not only a specific access technology, but also a communication technology for each generation established by various communication consultation organizations such as 3GPP, 3GPP2, WiFi, Bluetooth, IEEE, and ITU. For example, CDMA may be implemented with a radio technology such as universal terrestrial radio access (UTRA) or CDMA2000. TDMA may be implemented with a radio technology such as global system for mobile communications (GSM)/general packet radio service (GPRS)/enhanced data rates for GSM evolution (EDGE). OFDMA may be implemented with a wireless technology such as IEEE (institute of electrical and electronics engineers) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, E-UTRA (evolved UTRA), and the like. IEEE 802.16m is an evolution of IEEE 802.16e and provides backward compatibility with a system based on IEEE 802.16e. UTRA is part of a universal mobile telecommunications system (UMTS). 3rd generation partnership project (3GPP) long term evolution (LTE) is a part of evolved UMTS (E-UMTS) using evolved-UMTSterrestrial radio access (E-UTRA), and employs OFDMA in downlink and SC- in uplink. Adopt FDMA. As described above, the present embodiments may be applied to a wireless access technology currently disclosed or commercialized, and may be applied to a wireless access technology currently being developed or to be developed in the future.

Meanwhile, a terminal in the present specification is a generic concept that refers to a device including a wireless communication module that performs communication with a base station in a wireless communication system, and is used in WCDMA, LTE, NR, HSPA, and IMT-2020 (5G or New Radio). It should be interpreted as a concept that includes all of the UE (User Equipment) of, as well as the MS (Mobile Station), UT (User Terminal), SS (Subscriber Station), and wireless device in GSM. In addition, the terminal may be a user's portable device such as a smart phone according to the usage type, and in the V2X communication system, it may mean a vehicle, a device including a wireless communication module in the vehicle, and the like. In addition, in the case of a machine type communication system, it may mean an MTC terminal, an M2M terminal, a URLLC terminal, etc. equipped with a communication module so that machine type communication is performed.

The base station or cell of the present specification refers to the end of communication with the terminal in terms of the network, and Node-B (Node-B), eNB (evolved Node-B), gNB (gNode-B), LPN (Low Power Node), Sector, Site, various types of antennas, BTS (Base Transceiver System), Access Point, Point (e.g., Transmit Point, Receiving Point, Transmitting Point), Relay Node ), a mega cell, a macro cell, a micro cell, a pico cell, a femto cell, a remote radio head (RRH), a radio unit (RU), and a small cell. Also, the cell may mean including a bandwidth part (BWP) in the frequency domain. For example, the serving cell may mean an activation BWP of the terminal.

In the various cells listed above, since there is a base station that controls one or more cells, the base station can be interpreted in two meanings. 1) In relation to the radio area, the device itself may provide a mega cell, a macro cell, a micro cell, a pico cell, a femto cell, and a small cell, or 2) the radio area itself may be indicated. In 1), all devices that are controlled by the same entity that provide a predetermined wireless area are controlled by the same entity, or all devices that interact to form a wireless area in collaboration are instructed to the base station. A point, a transmission/reception point, a transmission point, a reception point, etc. may be an embodiment of a base station according to the configuration method of the wireless area. In 2), it is also possible to instruct the base station to the radio region itself to receive or transmit a signal from the viewpoint of the user terminal or the viewpoint of a neighboring base station.

In the present specification, a cell refers to a component carrier having coverage of a signal transmitted from a transmission/reception point or a coverage of a signal transmitted from a transmission/reception point, and the transmission/reception point itself. I can.

Uplink (Uplink, UL, or uplink) refers to a method of transmitting and receiving data to a base station by a UE, and downlink (Downlink, DL, or downlink) refers to a method of transmitting and receiving data to a UE by a base station. do. Downlink may refer to a communication or communication path from multiple transmission/reception points to a terminal, and uplink may refer to a communication or communication path from a terminal to multiple transmission/reception points. In this case, in the downlink, the transmitter may be a part of the multiple transmission/reception points, and the receiver may be a part of the terminal. In addition, in the uplink, the transmitter may be a part of the terminal, and the receiver may be a part of the multiple transmission/reception points.

Uplink and downlink transmit and receive control information through a control channel such as Physical Downlink Control CHannel (PDCCH), Physical Uplink Control CHannel (PUCCH), and the like, and physical downlink shared channel (PDSCH), physical uplink shared channel (PUSCH), etc. The same data channel is configured to transmit and receive data. Hereinafter, a situation in which signals are transmitted/received through channels such as PUCCH, PUSCH, PDCCH, and PDSCH may be expressed in the form of “transmitting and receiving PUCCH, PUSCH, PDCCH, and PDSCH”.

In order to clarify the description, hereinafter, the present technical idea is mainly described with a 3GPP LTE/LTE-A/NR (New RAT) communication system, but the present technical feature is not limited to the corresponding communication system.

3GPP develops 5G (5th-Generation) communication technology to meet the requirements of ITU-R's next-generation wireless access technology after research on 4G (4th-Generation) communication technology. Specifically, 3GPP is developing a new NR communication technology separate from 4G communication technology and LTE-A pro, which has improved LTE-Advanced technology as a 5G communication technology to meet the requirements of ITU-R. Both LTE-A pro and NR refer to 5G communication technology. Hereinafter, 5G communication technology will be described centering on NR when a specific communication technology is not specified.

The operation scenario in NR defined various operation scenarios by adding considerations to satellites, automobiles, and new verticals from the existing 4G LTE scenario.In terms of service, eMBB (Enhanced Mobile Broadband) scenario, high terminal density, but wide It is deployed in the range and supports the mMTC (Massive Machine Communication) scenario that requires a low data rate and asynchronous connection, and the URLLC (Ultra Reliability and Low Latency) scenario that requires high responsiveness and reliability and supports high-speed mobility. .

In order to satisfy this scenario, NR discloses a wireless communication system to which a new waveform and frame structure technology, a low latency technology, a mmWave support technology, and a forward compatible provision technology are applied. In particular, in the NR system, various technological changes are proposed in terms of flexibility to provide forward compatibility. The main technical features of the NR will be described below with reference to the drawings.

<NR system general>

1 is a diagram schematically showing a structure of an NR system to which this embodiment can be applied.

1, the NR system is divided into 5GC (5G Core Network) and NR-RAN parts, and NG-RAN controls user plane (SDAP/PDCP/RLC/MAC/PHY) and UE (User Equipment). It consists of gNBs and ng-eNBs that provide plane (RRC) protocol termination. The gNB mutually or the gNB and the ng-eNB are interconnected through the Xn interface. The gNB and ng-eNB are each connected to 5GC through the NG interface. The 5GC may include an Access and Mobility Management Function (AMF) in charge of a control plane such as a terminal access and mobility control function, and a User Plane Function (UPF) in charge of a control function for user data. NR includes support for both frequency bands below 6GHz (FR1, Frequency Range 1) and frequencies above 6GHz (FR2, Frequency Range 2).

gNB means a base station that provides NR user plane and control plane protocol termination to a terminal, and ng-eNB means a base station that provides E-UTRA user plane and control plane protocol termination to a terminal. The base station described in the present specification should be understood in a sense encompassing gNB and ng-eNB, and may be used as a means to distinguish between gNB or ng-eNB as necessary.

<NR wave form, numer roller and frame structure>

In NR, a CP-OFDM waveform using a cyclic prefix is used for downlink transmission, and CP-OFDM or DFT-s-OFDM is used for uplink transmission. OFDM technology is easy to combine with MIMO (Multiple Input Multiple Output), and has the advantage of being able to use a low complexity receiver with high frequency efficiency.

Meanwhile, in NR, since the requirements for data rate, delay rate, coverage, etc. are different for each of the three scenarios described above, it is necessary to efficiently satisfy the requirements for each scenario through the frequency band constituting an arbitrary NR system. . To this end, a technique for efficiently multiplexing a plurality of different numerology-based radio resources has been proposed.

Specifically, the NR transmission neuron is determined based on sub-carrier spacing and CP (cyclic prefix), and the value of μ is used as an exponent of 2 based on 15 kHz as shown in Table 1 below. It is changed to the enemy.

μ Subcarrier spacing Cyclic prefix Supported for data Supported for synch 0 15 Normal Yes Yes One 30 Normal Yes Yes 2 60 Normal, Extended Yes No 3 120 Normal Yes Yes 4 240 Normal No Yes

As shown in Table 1 above, the NR neuron can be classified into 5 types according to the subcarrier interval. This is different from LTE, one of the 4G communication technologies, where the subcarrier spacing is fixed at 15 kHz. Specifically, in NR, subcarrier intervals used for data transmission are 15, 30, 60, and 120 kHz, and subcarrier intervals used for synchronization signal transmission are 15, 30, 120, and 240 kHz. In addition, the extended CP is applied only to the 60 kHz subcarrier spacing. On the other hand, a frame structure in NR is defined as a frame having a length of 10 ms consisting of 10 subframes having the same length of 1 ms. One frame can be divided into 5 ms half frames, and each half frame includes 5 subframes. In the case of a 15 kHz subcarrier interval, one subframe consists of 1 slot, and each slot consists of 14 OFDM symbols. 2 is a diagram for explaining a frame structure in an NR system to which this embodiment can be applied.

Referring to FIG. 2, in the case of a normal CP, a slot is fixedly composed of 14 OFDM symbols, but the length in the time domain of the slot may vary according to the subcarrier interval. For example, in the case of a newer roller with a 15 kHz subcarrier spacing, a slot is 1 ms long and has the same length as the subframe. In contrast, in the case of a newer roller with a 30 kHz subcarrier interval, a slot consists of 14 OFDM symbols, but two slots may be included in one subframe with a length of 0.5 ms. That is, the subframe and the frame are defined with a fixed time length, and the slot is defined by the number of symbols, and the time length may vary according to the subcarrier interval.

Meanwhile, NR defines a basic unit of scheduling as a slot, and introduces a mini-slot (or sub-slot or non-slot based schedule) in order to reduce the transmission delay of the radio section. If a wide subcarrier spacing is used, the length of one slot is shortened in inverse proportion, so that transmission delay in the radio section can be reduced. The mini-slot (or sub-slot) is for efficient support for the URLLC scenario, and scheduling is possible in units of 2, 4, or 7 symbols.

In addition, unlike LTE, NR defines uplink and downlink resource allocation as a symbol level within one slot. In order to reduce HARQ delay, a slot structure capable of transmitting HARQ ACK/NACK directly within a transmission slot has been defined, and this slot structure is named and described as a self-contained structure.

NR is designed to support a total of 256 slot formats, of which 62 slot formats are used in 3GPP Rel-15. In addition, a common frame structure constituting an FDD or TDD frame is supported through a combination of various slots. For example, a slot structure in which all symbols of a slot are set to downlink, a slot structure in which all symbols are set to uplink, and a slot structure in which a downlink symbol and an uplink symbol are combined are supported. In addition, NR supports that data transmission is distributed and scheduled in one or more slots. Accordingly, the base station may inform the UE of whether the slot is a downlink slot, an uplink slot, or a flexible slot using a slot format indicator (SFI). The base station can indicate the slot format by indicating the index of the table configured through UE-specific RRC signaling using SFI, and dynamically indicates through Downlink Control Information (DCI) or statically or through RRC. It can also be quasi-static.

<NR physical resource>

Regarding the physical resource in NR, the antenna port, resource grid, resource element, resource block, bandwidth part, etc. are considered. do.

The antenna port is defined so that a channel carrying a symbol on an antenna port can be inferred from a channel carrying another symbol on the same antenna port. When the large-scale property of a channel carrying a symbol on one antenna port can be inferred from a channel carrying a symbol on another antenna port, the two antenna ports are QC/QCL (quasi co-located or quasi co-location) relationship. Here, the wide-range characteristic includes at least one of delay spread, Doppler spread, frequency shift, average received power, and received timing.

3 is a diagram illustrating a resource grid supported by a radio access technology to which the present embodiment can be applied.

Referring to FIG. 3, since the NR supports a plurality of neurons in the same carrier, a resource grid may exist according to each neuron in the resource grid. In addition, the resource grid may exist according to an antenna port, a subcarrier spacing, and a transmission direction.

A resource block consists of 12 subcarriers, and is defined only in the frequency domain. In addition, a resource element consists of one OFDM symbol and one subcarrier. Accordingly, as shown in FIG. 3, the size of one resource block may vary according to the subcarrier interval. In addition, NR defines “Point A” that serves as a common reference point for the resource block grid, a common resource block, and a virtual resource block.

4 is a diagram for explaining a bandwidth part supported by a wireless access technology to which the present embodiment can be applied.

In NR, unlike LTE where the carrier bandwidth is fixed at 20Mhz, the maximum carrier bandwidth is set from 50Mhz to 400Mhz for each subcarrier interval. Therefore, it is not assumed that all terminals use all of these carrier bandwidths. Accordingly, in the NR, as shown in FIG. 4, a bandwidth part (BWP) can be designated within the carrier bandwidth and used by the terminal. In addition, the bandwidth part is associated with one neurology and is composed of a subset of consecutive common resource blocks, and can be dynamically activated over time. The UE is configured with up to four bandwidth parts, respectively, in uplink and downlink, and data is transmitted and received using the active bandwidth part at a given time.

In the case of a paired spectrum, uplink and downlink bandwidth parts are independently set, and in the case of an unpaired spectrum, unnecessary frequency re-tuning between downlink and uplink operations is prevented. For this purpose, the downlink and uplink bandwidth parts are set in pairs to share a center frequency.

<NR initial connection>

In NR, the terminal accesses the base station and performs cell search and random access procedures to perform communication.

Cell search is a procedure in which a terminal synchronizes with a cell of a corresponding base station, obtains a physical layer cell ID, and obtains system information by using a synchronization signal block (SSB) transmitted by a base station.

5 is a diagram illustrating a synchronization signal block in a wireless access technology to which the present embodiment can be applied.

Referring to FIG. 5, an SSB consists of a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) occupying 1 symbol and 127 subcarriers, respectively, and a PBCH spanning 3 OFDM symbols and 240 subcarriers.

The terminal receives the SSB by monitoring the SSB in the time and frequency domain.

SSB can be transmitted up to 64 times in 5ms. A plurality of SSBs are transmitted in different transmission beams within 5 ms time, and the UE performs detection on the assumption that SSBs are transmitted every 20 ms period based on one specific beam used for transmission. The number of beams that can be used for SSB transmission within 5 ms time may increase as the frequency band increases. For example, up to 4 SSB beams can be transmitted under 3GHz, and up to 8 in a frequency band of 3 to 6GHz, and a maximum of 64 different beams in a frequency band of 6GHz or higher can be used to transmit SSBs.

Two SSBs are included in one slot, and the start symbol and the number of repetitions in the slot are determined according to the subcarrier interval as follows.

Meanwhile, the SSB is not transmitted at the center frequency of the carrier bandwidth, unlike the conventional LTE SS. That is, the SSB may be transmitted even in a place other than the center of the system band, and a plurality of SSBs may be transmitted in the frequency domain when broadband operation is supported. Accordingly, the UE monitors the SSB by using a synchronization raster, which is a candidate frequency location for monitoring the SSB. The carrier raster and synchronization raster, which are information on the center frequency of the channel for initial access, have been newly defined in NR, and the synchronization raster has a wider frequency interval than the carrier raster to support fast SSB search of the terminal. I can.

The UE can acquire the MIB through the PBCH of the SSB. The MIB (Master Information Block) includes minimum information for the terminal to receive remaining system information (RMSI, Remaining Minimum System Information) broadcast by the network. In addition, PBCH is information about the location of the first DM-RS symbol in the time domain, information for the UE to monitor SIB1 (e.g., SIB1 neurology information, information related to SIB1 CORESET, search space information, PDCCH Related parameter information, etc.), offset information between the common resource block and the SSB (the position of the absolute SSB in the carrier is transmitted through SIB1), and the like. Here, the SIB1 neurology information is equally applied to some messages used in the random access procedure for accessing the base station after the terminal completes the cell search procedure. For example, the neurology information of SIB1 may be applied to at least one of messages 1 to 4 for a random access procedure.

The aforementioned RMSI may mean System Information Block 1 (SIB1), and SIB1 is periodically broadcast (ex, 160ms) in a cell. SIB1 includes information necessary for the UE to perform an initial random access procedure, and is periodically transmitted through the PDSCH. In order for the UE to receive SIB1, it is necessary to receive newer roller information used for SIB1 transmission and CORESET (Control Resource Set) information used for SIB1 scheduling through the PBCH. The UE checks scheduling information for SIB1 using SI-RNTI in CORESET, and acquires SIB1 on the PDSCH according to the scheduling information. SIBs other than SIB1 may be periodically transmitted or may be transmitted according to the request of the terminal.

6 is a diagram for explaining a random access procedure in a radio access technology to which the present embodiment can be applied.

Referring to FIG. 6, when the cell search is completed, the UE transmits a random access preamble for random access to the base station. The random access preamble is transmitted through the PRACH. Specifically, the random access preamble is transmitted to the base station through a PRACH consisting of consecutive radio resources in a specific slot that is periodically repeated. In general, when a terminal initially accesses a cell, a contention-based random access procedure is performed, and when a random access is performed for beam failure recovery (BFR), a contention-free random access procedure is performed.

The terminal receives a random access response to the transmitted random access preamble. The random access response may include a random access preamble identifier (ID), a UL Grant (uplink radio resource), a temporary C-RNTI (Temporary Cell-Radio Network Temporary Identifier), and a TAC (Time Alignment Command). Since one random access response may include random access response information for one or more terminals, the random access preamble identifier may be included to inform which terminal the included UL Grant, temporary C-RNTI, and TAC are valid. The random access preamble identifier may be an identifier for the random access preamble received by the base station. TAC may be included as information for the UE to adjust uplink synchronization. The random access response may be indicated by a random access identifier on the PDCCH, that is, a Random Access-Radio Network Temporary Identifier (RA-RNTI).

Upon receiving a valid random access response, the terminal processes the information included in the random access response and performs scheduled transmission to the base station. For example, the UE applies TAC and stores a temporary C-RNTI. Also, by using UL Grant, data stored in the buffer of the terminal or newly generated data is transmitted to the base station. In this case, information for identifying the terminal should be included.

Finally, the terminal receives a downlink message for resolving contention.

<NR CORESET>

The downlink control channel in NR is transmitted in CORESET (Control Resource Set) having a length of 1 to 3 symbols, and transmits uplink/downlink scheduling information, SFI (Slot Format Index), and TPC (Transmit Power Control) information. .

In this way, NR introduced the concept of CORESET to secure system flexibility. CORESET (Control Resource Set) means a time-frequency resource for a downlink control signal. The terminal may decode the control channel candidate using one or more search spaces in the CORESET time-frequency resource. A QCL (Quasi CoLocation) assumption for each CORESET is set, and this is used to inform the characteristics of the analog beam direction in addition to the delay spread, Doppler spread, Doppler shift, and average delay, which are characteristics assumed by conventional QCL.

7 is a diagram for explaining CORESET.

Referring to FIG. 7, CORESET may exist in various forms within a carrier bandwidth within one slot, and CORESET may consist of up to 3 OFDM symbols in the time domain. In addition, CORESET is defined as a multiple of 6 resource blocks up to the carrier bandwidth in the frequency domain.

The first CORESET is indicated through the MIB as part of the initial bandwidth part configuration so that additional configuration information and system information can be received from the network. After establishing the connection with the base station, the terminal may receive and configure one or more CORESET information through RRC signaling.

<LTE sidelink>

In the existing LTE system, radio channels and radio protocols for direct communication (ie, sidelink) between terminals were designed to provide direct communication between terminals and V2X (especially V2V) services.

Regarding the sidelink, PSSS/SSSS, which is a synchronization signal for synchronization between a wireless sidelink transmitting end and a receiving end, and PSBCH (Physical Sidelink Broadcasting Channel) for transmitting and receiving a related sidelink MIB (Master Information Block) are defined, and discovery information Designs were made for a physical sidelink discovery channel (PSCCH) for transmission and reception, a physical sidelink control channel (PSCCH) for transmission and reception of sidelink control information (SCI), and a physical sidelink shared channel (PSSCH) for transmission and reception of sidelink data.

In addition, for radio resource allocation for a sidelink, a technique was developed in which mode 1 in which the base station allocates radio resources and mode 2 in which the terminal selects and allocates radio resources from a radio resource pool. In addition, the LTE system required additional technological evolution to satisfy the V2X scenario.

In this environment, 3GPP derived 27 service scenarios related to vehicle recognition in Rel-14 and determined major performance requirements according to road conditions. In addition, in recent Rel-15, six performance requirements were determined by deriving 25 more advanced service scenarios such as platoon driving, advanced driving, and long-distance vehicle sensors.

In order to satisfy these performance requirements, the development of technology to improve the performance of the sidelink technology developed based on the conventional D2D communication in accordance with the requirements of V2X has been conducted. Particularly, in order to apply to C-V2X (Cellular-V2X), technology that improves the physical layer design of the sidelink to be suitable for high-speed environments, resource allocation technology, and synchronization technology can be selected as major research technologies.

The sidelink described below refers to a link used for D2D communication developed after 3GPP Rel-12 and V2X communication after Rel-14, and each channel term, synchronization term, resource term, etc. are D2D communication requirements, V2X Regardless of the Rel-14, 15 requirements, they are described in the same terms. However, for convenience of understanding, the description will focus on the difference between the sidelinks that satisfy the V2X scenario requirements based on the sidelink for D2D communication in Rel-12/13 as needed. Accordingly, terms related to sidelinks to be described below are only to be described by dividing D2D communication/V2X communication/C-V2X communication for convenience of comparison and understanding, and are not limitedly applied to a specific scenario.

<Resource allocation>

8 is a diagram for explaining various scenarios for V2X communication.

Referring to FIG. 8, a V2X terminal (denoted as a vehicle, but variously settable such as a user terminal) may be located within the coverage of a base station (eNB or gNB or ng-eNB), or may be located outside the base station coverage. For example, communication may be performed between terminals within the coverage of the base station (UE N-1, UE G-1, and UE X), and between a terminal within the base station coverage and an external terminal (ex, UE N-1, UE N- 2) can also perform communication. Alternatively, communication may be performed between terminals (ex, UE G-1, UE G-2) outside the coverage of the base station.

In these various scenarios, radio resource allocation for communication is required in order for the corresponding terminal to perform communication using the sidelink, and radio resource allocation is largely divided into base station handling allocation and a method of selecting and allocating the terminal itself.

Specifically, in D2D, a method of allocating a resource by a UE includes a centralized method (Mode 1) in which the base station intervenes in resource selection and management, and a distributed method (Mode 2) in which the UE randomly selects a preset resource. Similar to D2D, there are a method in which a base station intervenes in resource selection and management in C-V2X (Mode 3) and a method in which a vehicle directly selects resources in V2X (Mode 4). In Mode 3, the base station schedules an SA (Scheduling Assignment) pool resource area and a DATA pool resource area allocated thereto to the transmitting terminal.

FIG. 9 shows an example of UE1 and UE2 performing sidelink communication, and a sidelink resource pool used by the UE1 and UE2.

Referring to FIG. 9, the base station is indicated as an eNB, but may be gNB or ng-eNB as described above. In addition, the terminal exemplarily shows a mobile phone, but may be applied in various ways, such as a vehicle and an infrastructure device.

In FIG. 9(a), the transmitting terminal UE1 may select a resource unit corresponding to a specific resource in a resource pool, which means a set of resources, and transmit a sidelink signal using the resource unit. The receiving terminal UE2 may receive a resource pool through which UE1 can transmit a signal and detect a transmission signal of the corresponding terminal.

Here, the resource pool may be notified by the base station when UE1 is in the connection range of the base station, and may be notified by another terminal or determined as a predetermined resource when it is outside the connection range of the base station. In general, the resource pool is composed of a plurality of resource units, and each terminal may select one or a plurality of resource units and use it for transmitting its own sidelink signal.

Referring to FIG. 9(b), it can be seen that the total frequency resources are divided into NF and the total time resources are divided into NT, so that a total of NF*NT resource units are defined. Here, it can be said that the corresponding resource pool is repeated at the NT subframe cycle. In particular, one resource unit may appear periodically and repeatedly as shown.

On the other hand, the resource pool can be subdivided into several types. First, it can be classified according to the contents of the sidelink signal transmitted from each resource pool. For example, the content of the sidelink signal may be classified, and a separate resource pool may be configured for each. As the content of the sidelink signal, there may be a scheduling assignment (SA), a sidelink data channel, and a discovery channel.

The SA provides information such as the location of resources used for transmission of the sidelink data channel that the transmitting terminal follows, and information such as modulation and coding scheme (MCS), MIMO transmission method, and timing advance (TA) necessary for demodulation of other data channels. It may be a signal containing. This signal may be multiplexed with sidelink data and transmitted on the same resource unit, and in this case, the SA resource pool may mean a pool of resources transmitted by multiplexing an SA with sidelink data.

On the other hand, the FDM scheme applied to V2X communication can reduce a delay time for data resource allocation after SA resource allocation. For example, a non-adjacent method for separating control channel resources and data channel resources in a time domain within one subframe and an adjacent method for continuously allocating control channels and data channels within one subframe are considered.

Meanwhile, when an SA is multiplexed and transmitted together with sidelink data on the same resource unit, only a sidelink data channel excluding SA information may be transmitted in a resource pool for a sidelink data channel. In other words, resource elements that were used to transmit SA information on individual resource units in the SA resource pool can still be used to transmit sidelink data in the sidelink data channel resource pool. The discovery channel may be a resource pool for a message that enables a transmitting terminal to discover itself by transmitting information such as its ID. Even when the content of the sidelink signal is the same, a different resource pool may be used according to the transmission/reception property of the sidelink signal.

For example, even in the same sidelink data channel or discovery message, a method for determining the transmission timing of a sidelink signal (for example, whether it is transmitted at the time of reception of a synchronization reference signal or transmitted by applying a certain TA there) or a resource allocation method (For example, whether the base station assigns transmission resources of individual signals to individual transmitting terminals or whether individual transmitting terminals select individual signal transmission resources in the pool), signal format (e.g., each sidelink signal is The number of symbols occupied in the frame, the number of subframes used for transmission of one sidelink signal), signal strength from the base station, transmission power strength of the sidelink terminal, etc. may be divided into different resource pools.

<Synchronization signal>

As described above, in the case of a V2X communication terminal, it is highly likely to be located outside the coverage of the base station. Even in this case, communication using the sidelink must be performed. For this, a problem in which a terminal located outside the coverage of a base station acquires synchronization is important.

Hereinafter, based on the above description, a method of synchronizing time and frequency in sidelink communication, particularly in communication between vehicles, vehicles and other terminals, and vehicles and infrastructure networks will be described.

D2D communication uses a Sidelink Synchronization Signal (SLSS), which is a synchronization signal transmitted from a base station, for time synchronization between terminals. In C-V2X, a satellite system (GNSS: Global Navigation Satellite System) can be additionally considered to improve synchronization performance. However, priority may be given to synchronization establishment or the base station may indicate information on priority. For example, in determining its transmission synchronization, the terminal preferentially selects a synchronization signal directly transmitted by the base station, and if it is located outside the coverage of the base station, it preferentially performs synchronization with the SLSS transmitted by the terminal inside the base station coverage. Fit.

On the other hand, a wireless terminal installed in a vehicle or a terminal mounted in a vehicle has relatively less battery consumption problems, and a satellite signal such as GPS can be used for navigation purposes, so time or frequency synchronization between terminals is set for the satellite signal. Can be used to Here, the satellite signal may correspond to a GNSS signal such as a GLObal NAvigation Satellite System (GLONAS), GALILEO, and BEIDOU in addition to the illustrated Global Positioning System (GPS).

Meanwhile, the sidelink synchronization signal may include a primary sidelink synchronization signal (PSSS) and a secondary sidelink synchronization signal (SSSS). The PSSS may be a Zadoff-chu sequence of a predetermined length or a structure similar to/modified/repeated to the PSS. In addition, unlike the DL PSS, other Zadoff Chu root indexes (eg, 26, 37) can be used. The SSSS may be an M-sequence or a structure similar/deformed/repeated to the SSS. If the terminals are synchronized from the base station, the SRN becomes the base station, and the SLSS becomes the PSS/SSS.

Unlike PSS/SSS of DL, PSSS/SSSS follows UL subcarrier mapping method. PSSCH (Physical Sidelink Synchronization Channel) is the basic system information that the UE needs to know first before transmitting and receiving sidelink signals (e.g., information related to SLSS, duplex mode (DM), TDD UL/DL configuration, and resources) It may be a channel through which pool related information, the type of application related to SLSS, subframe offset, broadcast information, etc.) are transmitted. The PSSCH may be transmitted on the same subframe as the SLSS or on a subsequent subframe. The DM-RS can be used for demodulation of the PSSCH.

The SRN may be a node that transmits SLSS and PSSCH. The SLSS may be in the form of a specific sequence, and the PSSCH may be in the form of a sequence representing specific information or a code word after pre-determined channel coding. Here, the SRN may be a base station or a specific sidelink terminal. In the case of partial network coverage or out of network coverage, the UE may be the SRN.

In addition, if necessary, the SLSS may be relayed for sidelink communication with an out of coverage terminal, and may be relayed through multiple hops. In the following description, relaying the synchronization signal is a concept including not only relaying the synchronization signal of the base station directly, but also transmitting a sidelink synchronization signal in a separate format in accordance with the synchronization signal reception time. In this way, since the sidelink synchronization signal is relayed, the in-coverage terminal and the out-of-coverage terminal can perform direct communication.

<NR sidelink>

As described above, unlike the LTE system-based V2X, there is a need for NR-based V2X technology in order to satisfy complex requirements such as autonomous driving.

In the case of NR V2X, it is intended to provide flexible V2X services in a wider variety of environments by applying the NR frame structure, newer rollers, and channel transmission/reception procedures. To this end, it is required to develop a resource sharing technology between a base station and a terminal, a sidelink carrier aggregation (CA) technology, a partial sensing technology for a pedestrian terminal, and a technology such as sTTI.

NR V2X decided to support unicast and groupcast as well as broadcast used in LTE V2X. At this time, it was decided to use the target group ID for groupcast and unicast, but it was decided to discuss whether to use the source ID later.

In addition, as it is decided to support HARQ for QOS, the control information also includes a HARQ process ID (HARQ Process ID). In LTE HARQ, PUCCH for HARQ is transmitted after four subframes after downlink transmission, but in NR HARQ, feedback timing is determined by, for example, a PUCCH resource indicator in DCI format 1_0 or 1_1 or HARQ feedback for PDSCH. PUCCH resources and feedback timing can be indicated by a timing indicator (PDSCH-to-HARQ feedback timing indicator).

10 is a diagram for explaining a method of bundling and transmitting HARQ feedback information in V2X.

Referring to FIG. 10, in LTE V2X, separate HARQ ACK/NACK information is not transmitted in order to reduce system overhead, and for data transmission safety, the transmitting terminal can retransmit data once according to the selection. However, the NR V2X can transmit HARQ ACK/NACK information in terms of data transmission stability, and in this case, overhead can be reduced by bundling and transmitting the corresponding information.

That is, when the transmitting terminal UE1 transmits three pieces of data to the receiving terminal UE2 and the receiving terminal generates HARQ ACK/NACK information for this, it may be bundled and transmitted through the PSCCH. In the drawing, it has been described that HARA ACK/NACK is transmitted through the PSCCH, but may be transmitted through a separate channel or another channel, and the bundled HARQ information may consist of 3 bits or less.

On the other hand, in FR1 for the frequency range below 3 GHz, 15 kHz, 30 kHz, 60 kHz, and 120 kHz were discussed as candidate groups as SCS (subcarrier spacing). In addition, for FR2 for a frequency region exceeding 3 GHz, 30 kHz, 60 kHz, 120 kHz, and 240 kHz were discussed as candidate groups by subcarrier spacing (SCS). NR V2X may support mini-slots (for example, 2/4/7 symbols) smaller than 14 symbols in the minimum scheduling unit.

As candidates for RS, DM-RS, PT-RS, CSI-RS, SRS, and AGC training signals were discussed.

As for the multiplexing of PSSCH associated with PSCCH, as shown in FIG. 11, the following four options were discussed. Option 2 is similar to multiplexing of PSCCH and PSSCH in LTE V2X.

Synchronization mechanism

NR V2X sidelink synchronization includes a sidelink synchronization signal(s) and PSBCH, and a sidelink source may include a UE along with GNSS and gNB.

Resource allocation

In NR V2X sidelink communication, at least two sidelink resource allocation modes, that is, mode 3 and mode 4 may be defined. In mode 3, the base station schedules sidelink resource(s) used by the terminal for sidelink transmission. In mode 4, the UE determines sidelink transmission resource(s) within sidelink resources configured by the base station or preconfigured sidelink resources.

Mode 4 can cover the following resource allocation sub-modes. That is, the UE automatically selects a sidelink resource for transmission, helps to select a sidelink resource for other UE(s), or consists of a grant configured for sidelink transmission, or a sidelink of another terminal(s) Transmission can be scheduled.

V2X resource pool (Sensing and selection windows)

The V2X terminal may perform message (or channel) transmission on a predefined (or signaled) resource pool. Here, the resource pool may mean a predefined resource(s) so that the UE performs a V2X operation (or a V2X operation). In this case, the resource pool may be defined in terms of, for example, time-frequency. Meanwhile, various types of V2X transmission resource pools may exist.

11 illustrates the type of a V2X transmission resource pool.

Referring to FIG. 11(a), V2X transmission resource pool #A may be a resource pool in which only (partial) sensing is allowed. The V2X transmission resource selected by (partial) sensing is semi-statically maintained at a certain period.

Referring to FIG. 11(b), V2X transmission resource pool #A may be a resource pool in which only random selection is allowed. In the V2X transmission resource pool #B, the UE may not perform (partial) sensing and may randomly select a V2X transmission resource in a selection window.

Here, as an example, in a resource pool in which only random selection is allowed, unlike a resource pool in which only (partial) sensing is allowed, the selected resource may be set to not be semi-statically reserved (/ signaling). The base station may be configured not to perform a sensing operation (based on scheduling allocation decoding/energy measurement) in order for the terminal to perform a V2X message transmission operation on the V2X transmission resource pool.

Meanwhile, although not shown in FIG. 11, a resource pool capable of both (partial) sensing and random selection may exist. The base station may inform that it can select the V2X resource in either of the partial sensing and the random selection.

In this specification, frequencies, frames, subframes, resources, resource blocks, regions, bands, subbands, control channels, data channels, synchronization signals, various reference signals, various signals, or various messages related to NR (New Radio) Can be interpreted as a meaning used in the past or present, or in various meanings used in the future.

New Radio (NR)

NR, which has been recently conducted in 3GPP, has been designed to satisfy not only an improved data rate compared to LTE, but also a variety of QoS requirements for each subdivided and detailed usage scenario. In particular, eMBB (enhancement mobile broadband), mMTC (massive machine type communication), and URLLC (Ultra Reliable and Low Latency Communications) were defined as representative service requirements of NR, and each service requirement (usage scenario) required. As a method for satisfying the requirements, a flexible frame structure design compared to LTE/LTE-Advanced is required.

Each usage scenario has different requirements for data rates, latency, reliability, coverage, etc., so the frequency constituting an arbitrary NR system A radio resource unit based on different numerology (e.g., subcarrier spacing, subframe, TTI, etc.) as a method to efficiently satisfy the request for each service requirement (usage scenario) through the band It is designed to be efficiently multiplexed.

As one method for this, based on TDM, FDM or TDM/FDM through one or a plurality of NR component carriers (s) for numerology having different subcarrier spacing values. Discussion has been made on a method of multiplexing and supporting a method and a method of supporting one or more time units in configuring a scheduling unit in a time domain. In this regard, in NR, a subframe has been defined as a type of time domain structure, and a reference numerology for defining a corresponding subframe duration As an example, it was decided to define a single subframe duration composed of 14 OFDM symbols of normal CP overhead based on 15kHz Sub-Carrier Spacing (SCS) as in LTE. Accordingly, in NR, a subframe has a time duration of 1 ms. However, unlike LTE, a subframe of NR is an absolute reference time duration, and a slot and a mini-slot as a time unit that is the basis of the actual uplink/downlink data scheduling. ) Can be defined. In this case, the number of OFDM symbols constituting the corresponding slot and the y value are determined to have a value of y=14 regardless of the SCS value in the case of normal CP.

Accordingly, any slot consists of 14 symbols, and according to the transmission direction of the corresponding slot, all symbols are used for downlink transmission, or all symbols are used for uplink transmission (UL transmission), or may be used in the form of a downlink portion + a gap + an uplink portion (UL portion).

In addition, a mini-slot composed of fewer symbols than the slot is defined in an arbitrary numerology (or SCS), and based on this, a short time domain scheduling interval for uplink/downlink data transmission/reception (time-domain Scheduling interval) may be set or a long time-domain scheduling interval for uplink/downlink data transmission and reception may be configured through slot aggregation.

In particular, in the case of transmission and reception of latency critical data such as URLLC, the 1ms (14 symbols)-based frame structure defined in a numerology-based frame structure with a small SCS value such as 15kHz When scheduling is performed in units of slots, it may be difficult to satisfy the latency requirement. For this purpose, mini-slots composed of fewer OFDM symbols than the corresponding slots are defined, and based on this, critical to the same delay rate as the URLLC. (latency critical) data can be defined to be scheduled.

Or, as described above, by multiplexing and supporting numerology having different SCS values in one NR carrier by TDM and/or FDM method, each numerology A method of scheduling data according to a latency requirement based on a defined slot (or mini slot) length is also being considered. For example, as shown in FIG. 12 below, when the SCS is 60 kHz, the symbol length is reduced by about 1/4 compared to the SCS 15 kHz, so when one slot is configured with the same 14 OFDM symbols, the 15 kHz-based While the slot length becomes 1 ms, the slot length based on 60 kHz is reduced to about 0.25 ms.

As described above, in NR, by defining different SCS or different TTI lengths, a discussion on a method of satisfying the requirements of URLLC and eMBB is in progress.

Wide bandwidth operations

In the case of an existing LTE system, a scalable bandwidth operation for an arbitrary LTE component carrier (CC) was supported. That is, according to the frequency deployment scenario, in configuring one LTE CC, a random LTE operator can configure a bandwidth of a minimum of 1.4 MHz to a maximum of 20 MHz, and a normal LTE terminal has one LTE For the CC, transmission and reception capabilities of 20 MHz bandwidth were supported.

However, in the case of NR, the design has been made to enable support for NR terminals having different transmission/reception bandwidth capabilities through one wideband NR CC, and accordingly, as shown in FIG. 13 below. Likewise, by configuring one or more bandwidth parts (BWP, bandwidth part(s)) composed of subdivided bandwidths for arbitrary NR CCs, different bandwidth part configurations for each terminal and activation are flexible ( It is required to support a flexible) wider bandwidth operation.

Specifically, in the NR, one or more bandwidth parts can be configured through one serving cell configured from the viewpoint of the terminal, and the corresponding terminal can configure one downlink bandwidth part in the corresponding serving cell ( DL bandwidth part) and one UL bandwidth part (UL bandwidth part) is activated (activation) to be used for uplink/downlink data transmission/reception. In addition, when a plurality of serving cells are configured in the corresponding terminal, that is, even for the terminal to which CA is applied, one downlink bandwidth part and/or uplink bandwidth part is activated for each serving cell. Thus, it is defined to be used for uplink/downlink data transmission/reception by using radio resources of a corresponding serving cell.

Specifically, an initial bandwidth part for an initial access procedure of a terminal in an arbitrary serving cell is defined, and one or more terminal specific (UE) through dedicated RRC signaling for each terminal. A -specific) bandwidth part (bandwidth part(s)) may be configured, and a default bandwidth part for a fallback operation may be defined for each terminal.

However, in an arbitrary serving cell, a plurality of downlink and/or uplink bandwidth parts are simultaneously activated and used according to the configuration of the terminal's capability and bandwidth part(s). However, in NR rel-15, only one downlink bandwidth part and an uplink bandwidth part (UL bandwidth part) can be activated and used at a random time in an arbitrary terminal. .

LTE sidelink

In the existing LTE system, a radio channel and radio protocol design for sidelink transmission and reception, which is a direct link between terminals, has been made to provide direct communication between terminals and V2X (especially V2V) services. In this regard, PSSS/SSSS, which is a synchronization signal for synchronization between a radio sidelink transmitting end and a receiving end, and a Physical Sidelink Broadcasting Channel (PSBCH) for transmitting and receiving a related sidelink MIB (Master Information Block) are defined, and discovery information Designs were made for a physical sidelink discovery channel (PSCCH) for transmission and reception, a physical sidelink control channel (PSCCH) for transmission and reception of sidelink control information (SCI), and a physical sidelink shared channel (PSSCH) for transmission and reception of sidelink data. .

HARQ ACK/NACK feedback resource allocation method

According to the PUCCH resource allocation method for HARQ ACK/NACK feedback of the terminal defined in the NR, the base station configures a PUCCH resource set consisting of one or more PUCCH resources for an arbitrary terminal, and HARQ ACK/ for any PDSCH transmission. It is defined to indicate PUCCH resource information to be used for NACK feedback through an ACK Resource Indicator (ARI) information area of DCI. However, the PUCCH resource set is configured for each UL BWP configured for the corresponding UE, and separate PUCCH resource sets are defined according to the payload size of HARQ ACK/NACK for any UL BWP.

Hereinafter, a method of transmitting and receiving HARQ feedback information for sidelink transmission will be described in detail with reference to related drawings.

In the present disclosure, a transmitting terminal (Tx UE) refers to a terminal that transmits a PSCCH and a corresponding PSSCH to a receiving terminal through a sidelink. In addition, a receiving terminal (Rx UE) refers to a terminal that receives a PSCCH and a corresponding PSSCH from a transmitting terminal through a sidelink.

14 is a diagram illustrating a procedure for a transmitting terminal to transmit a sidelink channel state information reference signal (SL CSI-RS) to a receiving terminal according to an embodiment.

Referring to FIG. 14, the transmitting terminal may receive activation information of sidelink channel state information (CSI) reporting (S1400).

In order to obtain sidelink channel state information between the transmitting terminal and the receiving terminal, the transmitting terminal may transmit a sidelink channel state information reference signal (SL CSI-RS) to the receiving terminal. The receiving terminal may be configured to calculate channel state information based on the received SL CSI-RS, and to perform CSI reporting through a physical sidelink feedback channel (PSFCH) or PSSCH.

Therefore, in order to obtain sidelink CSI, CSI reporting must be enabled for the receiving terminal. According to an example, CSI reporting may be activated by a higher layer parameter. The transmitting terminal may receive information on whether to activate CSI reporting through higher layer signaling.

Referring back to FIG. 14, the transmitting terminal may determine whether to transmit the sidelink channel state information reference signal (SL CSI-RS) based on activation information of CSI reporting (S1410).

According to an example, the transmitting terminal may be configured to transmit the SL CSI-RS to the receiving terminal when CSI reporting is activated. The transmitting terminal determines whether to transmit the SL CSI-RS to the receiving terminal for which CSI reporting is activated, and determines whether to transmit the SL CSI-RS to the receiving terminal through a sidelink control information format (SCI format). Can be transmitted.

According to an example, when transmitting any PSSCH, whether or not to transmit SL CSI-RS may be dynamically indicated. That is, when transmitting a PSSCH for an arbitrary receiving terminal, an information region for indicating whether to transmit a CSI-RS through a DCI format or an SCI format for transmitting the corresponding PSSCH allocation information is defined, and based on this, the corresponding PSSCH transmission is CSI -It can indicate whether RS transmission is included.

That is, the transmitting terminal may set a predetermined information area included in the SCI format, for example, a value of the CSI request field, according to whether or not the determined SL CSI-RS is transmitted. The receiving terminal may receive the SL CSI-RS according to the value of the CSI request field included in the received SCI format.

Referring back to FIG. 14, the transmitting terminal may transmit the SL CSI-RS to the receiving terminal within the resources allocated to the physical sidelink shared channel (PSSCH) transmission (S1420).

When it is determined that the transmitting terminal transmits the SL CSI-RS, the transmitting terminal may transmit the SL CSI-RS to the receiving terminal within the resources allocated for PSSCH transmission. To this end, an SL CSI-RS that can be used for obtaining channel state information may be configured by a base station, a transmitting terminal, or a scheduling terminal, and configuration information for the SL CSI-RS may be transmitted to the receiving terminal.

According to an example, for transmission of SL CSI-RS, a first symbol in a resource block used for transmission of SL CSI-RS and frequency resource allocation information may be configured through a higher layer parameter. The transmitting terminal is based on the first symbol in the resource block used for transmission of the SL CSI-RS configured by higher layer signaling and the frequency resource allocation information within the resource allocated for PSSCH transmission for the receiving terminal, the SL CSI-RS Can be transmitted to the receiving terminal.

The receiving terminal may receive the SL CSI-RS, obtain channel state information based on the received SL CSI-RS, and report the CSI through the PSFCH. For this, according to an example, PSFCH resource allocation information may be dynamically indicated through DCI or SCI including resource allocation information for PSSCH transmitted through PDCCH or PSCCH from a base station, a transmitting terminal, or a scheduling terminal.

For example, a PSFCH resource indication information region for CSI reporting of a receiving terminal may be included in the DCI format or the SCI format. Through this, the PSFCH resource for CSI reporting of the receiving terminal may be determined.

When the receiving terminal performs CSI reporting through the determined PSFCH resource, CSI can be obtained in the transmitting terminal.

As another example, the receiving terminal receives the SL CSI-RS, obtains channel state information based on the received SL CSI-RS, constructs a higher layer message for reporting CSI, and sends it to the transmitting terminal through the PSSCH. Can be transmitted.

Accordingly, it is possible to provide a method and apparatus for transmitting and receiving a reference signal between a transmitting terminal and a receiving terminal in order to obtain channel state information for sidelink transmission in the NR.

15 is a diagram illustrating a procedure for a receiving terminal to receive an SL CSI-RS from a transmitting terminal according to an embodiment.

Referring to FIG. 15, a receiving terminal determines whether to transmit based on activation information of CSI reporting within a resource allocated for sidelink data channel (Physical Sidelink Shared Channel; PSSCH) transmission, a sidelink channel state information reference signal ( Sidelink Channel State Information Reference Signal; SL CSI-RS) can be received from the transmitting terminal (S1500).

In order to acquire sidelink channel state information between the transmitting terminal and the receiving terminal, the receiving terminal may receive the SL CSI-RS from the transmitting terminal. The receiving terminal may be configured to calculate channel state information based on the received SL CSI-RS, and to perform CSI reporting through PSFCH or PSSCH.

Therefore, in order to obtain sidelink CSI, CSI reporting must be enabled for the receiving terminal. According to an example, CSI reporting may be activated by a higher layer parameter. The transmitting terminal may receive information on whether to activate CSI reporting through higher layer signaling.

The transmitting terminal may determine whether to transmit the sidelink channel state information reference signal (SL CSI-RS) based on the activation information of CSI reporting. According to an example, the transmitting terminal may be configured to transmit the SL CSI-RS to the receiving terminal when CSI reporting is activated. When the transmitting terminal determines whether to transmit the SL CSI-RS to the receiving terminal for which CSI reporting is activated, the receiving terminal transmits the SL CSI-RS from the transmitting terminal through the Sidelink Control Information format (SCI format). You can receive whether or not to send.

According to an example, when transmitting any PSSCH, whether or not to transmit SL CSI-RS may be dynamically indicated. That is, when transmitting a PSSCH for an arbitrary receiving terminal, an information region for indicating whether to transmit CSI-RS through a DCI format or SCI format for transmitting the corresponding PSSCH allocation information is defined, and based on this, the corresponding PSSCH transmission is CSI. -It can indicate whether RS transmission is included.

That is, the transmitting terminal may set a predetermined information area included in the SCI format, for example, a value of the CSI request field, according to whether or not the determined SL CSI-RS is transmitted. The receiving terminal may receive the SL CSI-RS according to the value of the CSI request field included in the received SCI format.

The receiving terminal may transmit the SL CSI-RS from the transmitting terminal within the resources allocated for receiving a physical sidelink shared channel (PSSCH). When the transmitting terminal determines to transmit the SL CSI-RS, the receiving terminal may receive the SL CSI-RS from the transmitting terminal within resources allocated for PSSCH transmission. To this end, an SL CSI-RS that can be used for obtaining channel state information may be configured by a base station, a transmitting terminal, or a scheduling terminal, and configuration information for the SL CSI-RS may be received by the receiving terminal.

According to an example, for transmission of SL CSI-RS, a first symbol in a resource block used for transmission of SL CSI-RS and frequency resource allocation information may be configured through a higher layer parameter. The receiving terminal is based on the first symbol and frequency resource allocation information in the resource block used for transmission of the SL CSI-RS configured by higher layer signaling within the resources allocated for PSSCH reception for the corresponding receiving terminal, the SL CSI-RS Can be received from the transmitting terminal.

Referring back to FIG. 15, the receiving terminal may perform CSI reporting based on the received SL CSI-RS (S1510).

The receiving terminal may receive the SL CSI-RS, obtain channel state information based on the received SL CSI-RS, and report the CSI through the PSFCH. For this, according to an example, PSFCH resource allocation information may be dynamically indicated through DCI or SCI including resource allocation information for PSSCH transmitted through PDCCH or PSCCH from a base station, a transmitting terminal, or a scheduling terminal.

For example, a PSFCH resource indication information region for CSI reporting of a receiving terminal may be included in the DCI format or the SCI format. Through this, the PSFCH resource for CSI reporting of the receiving terminal may be determined.

When the receiving terminal performs CSI reporting through the determined PSFCH resource, CSI can be obtained in the transmitting terminal.

As another example, the receiving terminal may perform CSI reporting through a higher layer message, and in this case, the transmitting terminal may obtain corresponding CSI information through the PSSCH transmitted from the receiving terminal.

Accordingly, it is possible to provide a method and apparatus for transmitting and receiving a reference signal between a transmitting terminal and a receiving terminal in order to obtain channel state information for sidelink transmission in the NR.

Hereinafter, each embodiment related to transmission and reception of a reference signal for acquiring channel state information during sidelink transmission in NR will be described in detail with reference to the related drawings.

Existing LTE based Radio resource allocation for V2X data transmission and reception through a sidelink may be performed in a distributed method or a centralized method. That is, in the resource pool configured by the base station or pre-configured (pre-configured), the transmitting terminal (transmitter node) for sidelink data transmission, for example, a sub-channel ), and a PSCCH including a PSSCH and scheduling control information for a corresponding PSSCH may be transmitted through this. Alternatively, the base station transmits sidelink resource allocation information for a random transmitting terminal to the corresponding transmitting terminal through the PDCCH, and the transmitting terminal transmits the corresponding PSCCH and PSSCH through the sidelink resources allocated from the base station. Can be transmitted. As described above, as a method of transmitting wireless data through a sidelink, a transmission mode 3 scheme scheduled by a base station or a distributed-based transmission mode 4 has been defined.

Similarly, for NR-based V2X, mode 1 in which scheduling for sidelink transmission resources is allocated by a base station (gNB) and mode 2 in which scheduling is allocated by a transmitting terminal or an arbitrary scheduling UE were defined. Contents described in the present disclosure may be applied regardless of mode 1 and mode 2, unless contrary to the technical idea. In addition, in the case of NR-based V2X, not only broadcast, but also unicast or groupcast-based sidelink transmission and reception may be supported.

In order for the base station to acquire downlink channel state information (CSI) for a terminal, the base station transmits a channel state information reference signal (CSI-RS) through a downlink slot, and Based on this, a series of CSI acquisition methods for transmitting CSI reporting information to the base station are defined in LTE and NR. To this end, the base station transmits CSI-RS transmission resource configuration information for an arbitrary terminal to each terminal through UE-specific higher layer signaling, and the terminal accordingly transmits the CSI-RS transmission resource configuration information from the base station to each terminal. Is received, CSI is calculated based on this, and it is reported to the base station through PUCCH or PUSCH. The base station may configure/instruct CSI reporting, which is periodic, semi-persistently or aperiodic of the terminal.

Similarly, when supporting sidelink unicast or groupcast, the transmitting terminal (Tx UE) acquires the CSI for the sidelink with the receiving terminal (Rx UE), and transmits PSCCH or PSSCH based on this. For link adaptation can be applied. To this end, a random reference signal for CSI calculation must be transmitted from the transmitting terminal to the receiving terminal, and based on this, a series of processes of acquiring CSI from the receiving terminal and feeding it back to the transmitting terminal are required.

In this disclosure, a method for configuring and transmitting control information for transmitting a reference signal from a transmitting terminal for obtaining CSI in a sidelink and a CSI reporting method for a receiving terminal based on the same are proposed.

Example 1. Reference signal setup for CSI acquisition (acquisition)

CSI-RS is separately defined as a reference signal for obtaining CSI for downlink of a Uu interface between the base station and the terminal.

Likewise, a sidelink CSI-RS (SL CSI-RS) for obtaining CSI for a sidelink may be defined, and based on this, it may be defined to obtain CSI for a sidelink. Alternatively, a separate sidelink CSI-RS may not be defined, but a different sidelink reference signal (sidelink RS) may be defined to be used for CSI acquisition. For example, when transmitting a PSSCH, a DM-RS for demodulation of a corresponding PSSCH or a phase tracking reference signal (PT-RS) for correcting phase noise, a tracking reference signal (TRS), etc. are CSI It can be defined to be used for acquisition purposes.

In this way, when one or more reference signals can be used for sidelink CSI acquisition, a reference signal to be used for CSI acquisition by the corresponding terminal may be defined or indicated for any sidelink terminal. For example, a base station, a transmitting terminal, or a scheduling UE is defined to transmit reference signal configuration information to be used by the corresponding terminal to obtain sidelink CSI with the transmitting terminal through higher layer signaling for an arbitrary receiving terminal. I can.

For example, if a sidelink CSI-RS is defined, among all reference signals that may be included when transmitting a sidelink PSSCH such as CSI-RS, DM-RS, and PT-RS, a reference that can be used by the corresponding terminal for CSI acquisition The signal can be set by the base station, the transmitting terminal, or the scheduling terminal and transmitted to the receiving terminal. In this case, the information is transmitted through PDSCH or PSSCH through UE-specific or cell-specific/UE-group common higher layer signaling, or L1 control signaling (L1 control signaling) may be indicated through PDCCH or PSCCH. Through the reference signal configuration information for obtaining the sidelink CSI, the receiving terminal can obtain reference signal information to be used for obtaining the sidelink CSI. In this case, one reference signal or one or more reference signals for any receiving terminal may be set as a reference signal for sidelink CSI acquisition.

Example 2. Sidelink CSI-RS configuration

When a separate sidelink CSI-RS is defined, it is necessary to define a method for allocating time and frequency interval resources for transmission of the corresponding CSI-RS and transmitting the corresponding allocation information to the receiving terminal.

As one method for this, the CSI-RS transmission for any receiving terminal may be limited to be performed through the PSSCH transmission resource allocated for the corresponding receiving terminal.

In this case, as a method for allocating time period resources of the CSI-RS for the corresponding receiving terminal, the time period resources of the CSI-RS may be fixed to the last symbol or the last N symbols of the allocated PSSCH. In the case of the last N symbols, the corresponding N value may be set through higher layer signaling. Alternatively, the corresponding CSI-RS transmission symbol may be determined by the duration of the PSSCH allocated to be received by the receiving terminal through the sidelink, that is, the number of symbols.

Frequency interval resource allocation for CSI-RS transmission, that is, sub-carrier allocation, may be determined in units of PRBs. That is, a sub-carrier index (s) to be used for CSI-RS transmission in one PRB is determined, and the same sub-carrier index in each PRB for all PRBs allocated for PSSCH transmission (S) may be used for CSI-RS transmission. In this case, the subcarrier index(s) may be set to be semi-static by the base station, the transmitting terminal, or the scheduling terminal, and transmitted through higher layer signaling. Alternatively, the corresponding subcarrier index(s) may be dynamically indicated through PDCCH or PSCCH, or may be determined as a function of a transmitting terminal, a receiving terminal, or a cell ID.

As another method, frequency interval resource allocation for CSI-RS transmission, that is, subcarrier allocation, may vary according to the number of PRBs allocated for PSSCH transmission. Specifically, according to the number of RPBs, the density of CSI-RS transmission resources on the frequency axis, that is, the number of subcarriers used as CSI-RSs when substituted with one PRB may vary.

Alternatively, a CSI-RS allocation pattern of a plurality of time/frequency sections is defined, or a CSI-RS allocation pattern of a plurality of time/frequency sections is set through higher layer signaling in a base station, a transmitting terminal, or a scheduling terminal, CSI-RS allocation pattern information to be used when allocating arbitrary PSSCH transmission resources can be defined to be indicated through a corresponding DCI format or SCI format.

Additionally, when any PSSCH is transmitted, whether or not CSI-RS is transmitted may be defined to be dynamically indicated. That is, when transmitting a PSSCH for an arbitrary receiving terminal, an information region for indicating whether to transmit a CSI-RS through a DCI format or an SCI format for transmitting the corresponding PSSCH allocation information is defined, and based on this, the corresponding PSSCH transmission is CSI -It can indicate whether RS transmission is included.

Embodiment 3. PSFCH resource setting method for CSI reporting

PSFCH for sidelink control information feedback of the receiving terminal is defined. The sidelink control feedback information may be HARQ ACK/NACK feedback information and CSI reporting information according to PSSCH reception. In the present disclosure, a specific CSI reporting method of a receiving terminal and a PSFCH resource allocation method for the same are proposed.

When CSI reporting is enabled, any receiving terminal may define to report CSI through PSFCH in response to PSSCH reception of the corresponding terminal. Specifically, any receiving terminal may be defined to report CSI in response to all PSSCH receptions. As another method, it may be defined to report CSI in response to reception of any N PSSCHs. In this case, the corresponding N value may be set from the base station, the transmitting terminal, or the scheduling terminal through higher layer signaling. Alternatively, an information region for CSI reporting indication may be defined through a DCI format or an SCI format for transmitting PSSCH allocation information, and whether or not CSI reporting for an arbitrary receiving terminal may be dynamically indicated through this.

Additionally, a CSI reporting method for an arbitrary receiving terminal may be configured through higher layer signaling from a base station, a transmitting terminal, or a scheduling terminal, and one of the above-described CSI reporting methods may be applied based on this.

Hereinafter, a method of allocating PSFCH resources for CSI reporting is proposed. As a method for this, the corresponding PSFCH resource allocation information is a dynamic indication through DCI or SCI including resource allocation information for PSSCH transmitted through PDCCH or PSCCH from a base station, a transmitting terminal, or a scheduling terminal. Can be. Specifically, a PSFCH resource indication for CSI reporting of the corresponding terminal in the DCI format or SCI format for transmitting PSSCH scheduling control information for the corresponding receiving terminal to any receiving terminal in which CSI reporting is enabled (resource indication) It can be made to include an information area. Through this, it can be defined to determine the PSFCH resource for CSI reporting of the corresponding terminal.

However, in this case, the PSFCH resource pool (or PSFCH resource set) in which the corresponding PSFCH resource indication is made is set through higher layer signaling by the base station, the transmitting terminal, or the scheduling terminal, or in an arbitrary PSSCH. An associated PSFCH resource pool or an associated PSFCH resource set may be configured. At this time, the associated PSFCH or associated PSFCH resource pool or associated PSFCH resource set configuration information is timing gap information between the slot in which the corresponding PSSCH transmission is made or the slot in which the PSSCH resource pool in which the corresponding PSSCH is transmitted is configured, the PSFCH resource pool or It may include time resource allocation information for configuring the PSFCH resource set or PSFCH sub-channel ID allocation information. Here, the time resource allocation information for configuring the PSFCH resource pool or the PSFCH resource set may be, for example, symbol allocation information. In addition, frequency resource and sequence allocation information of the PSFCH resource pool or PSFCH resource set may include: 1. PRB resource allocation information and sequence allocation information of the associated PSFCH resource pool or PSFCH resource set, or 2. The associated PSFCH resource pool or It may be PRB resource allocation information and sequence allocation information of each PSFCH constituting the PSFCH resource set.

Based on this, a PSFCH resource indication for CSI reporting, for example, a PSFCH resource index or a PSFCH subchannel ID indication is made through the DCI format or SCI format.

Or, as another method of the PSFCH resource indication, it can be defined so that an implicit indication (implicit indication) is made. For example, the associated PSFCH as a function of the radio resource (e.g., the lowest VRB or PRB index, the slot index or the lowest PSSCH subchannel ID, etc.) in which the PSCCH transmission for the corresponding receiving terminal is performed. It can be defined that the PSFCH resource indication based on the resource pool or the associated PSFCH resource set is made.

However, when the dynamic PSFCH resource allocation is performed, the timing gap information between any PSSCH reception slot and the corresponding PSFCH transmission slot is not included in the associated PSFCH resource pool or PSFCH resource set configuration information through higher layer signaling. Instead, it may be dynamically indicated through DCI format/SCI format or fixed to an arbitrary value.

As another method, PSFCH resources for corresponding CSI reporting may be semi-statically allocated through higher layer signaling. In this case, the upper layer parameter for allocating the PSFCH resource is the timing gap information between the PSSCH receiving slot and the slot in which the PSFCH resource is allocated for CSI reporting corresponding thereto, PSFCH subchannel ID or PRB and sequence resource allocation information, etc. It may include.

In addition, when both HARQ ACK/NACK feedback and CSI reporting are enabled in response to PSSCH reception in any receiving terminal, the corresponding receiving terminal transmits one PSFCH through corresponding HARQ ACK/NACK information and CSI reporting information. Can be multiplexed and transmitted. In this case, a separate PSFCH resource setting/instruction for CSI reporting is not made, and PSFCH resource setting information for HARQ ACK/NACK feedback, that is, an associate PSFCH resource pool or a higher layer configuration for setting a PSFCH resource set (higher layer configuration) information or indication information, that is, according to the PSFCH resource indication information or implicit indication information), the multiplexed UCI (HARQ ACK/NACK + CSI reporting) may be defined to be transmitted. That is, it may be defined that PSFCH resource allocation for transmission of the multiplexed sidelink feedback information is performed according to a PSFCH resource mapping rule for HARQ ACK/NACK feedback.

Alternatively, even in this case, the PSFCH for CSI reporting may be defined to be transmitted separately from the PSFCH for HARQ ACK/NACK feedback. For example, if HARQ ACK/NACK feedback and CSI reporting corresponding to any one PSSCH reception are configured or instructed to be performed through different slots, the corresponding UEs each receive HARQ ACK/NACK feedback and CSI through separate PSFCHs. Each reporting is to be transmitted, and CSI reporting information is also multiplexed and transmitted through PSFCH allocated for HARQ ACK/NACK feedback only when the corresponding sidelink feedback information transmission is set or instructed to occur through one slot. can do. Alternatively, on the contrary, it may be defined to transmit the corresponding HARQ ACK/NACK information multiplexed with CSI reporting information through a PSFCH allocated for CSI reporting.

Alternatively, regardless of the sidelink feedback information type, an associated PSFCH corresponding to any PSSCH reception may be defined, and all feedback information defined to be transmitted by the receiving terminal in response to the corresponding PSSCH reception through the associated PSFCH May be defined to multiplex and transmit. That is, a common PSFCH resource allocation rule for both HARQ ACK/NACK feedback information and CSI reporting may be defined, and indication information through upper layer parameter(s) or L1 control signaling for this is also commonly defined. Can be.

For example, configuration information for the associated PSFCH or the associated PSFCH resource pool or the associated PSFCH resource set corresponding to the PSSCH resource pool in which the PSSCH transmission or the corresponding PSSCH transmission is performed is transmitted from the base station/transmitting terminal/scheduling terminal through higher layer signaling. It can be defined to be transmitted to the receiving terminal. The associated PSFCH or associated PSFCH resource pool or associated PSFCH resource set configuration information includes timing gap information between the corresponding PSSCH transmission or the PSSCH resource pool in which the corresponding PSSCH transmission is performed, time resource allocation information of the PSFCH resource pool or PSFCH resource set, and PSFCH frequency resources. And sequence allocation information or PSFCH subchannel ID allocation information.

Here, the time resource allocation information of the PSFCH resource pool or the PSFCH resource set may be, for example, symbol allocation information. In addition, the PSFCH frequency resource and sequence allocation information may include: 1. PRB resource allocation information and sequence allocation information of the associated PSFCH resource pool or PSFCH resource set, or 2. of each PSFCH constituting the associated PSFCH resource pool or PSFCH resource set. It may be PRB resource allocation information and sequence allocation information.

In addition, the PSFCH resource for transmission of sidelink feedback information (ie, HARQ ACK/NACK or CSI reporting or HARQ ACK/NACK + CSI reporting) corresponding to any PSSCH within the associated PSFCH resource pool or PSFCH resource set is DCI format Alternatively, it may be dynamically indicated (PSFCH resource index indication or PSFCH subchannel ID indication) through the SCI format, or may be implicitly indicated. As a form of implicit indication method, the PSFCH resource allocation (PRB + sequence allocation or PSFCH subchannel ID allocation) as a function of the lowest subchannel ID or lowest PRB in which the corresponding PSCCH or PSSCH was transmitted You can define this to happen.

Accordingly, it is possible to provide a method and apparatus for transmitting and receiving a reference signal between a transmitting terminal and a receiving terminal in order to obtain channel state information for sidelink transmission in the NR.

Hereinafter, configurations of a receiving terminal and a transmitting terminal capable of performing some or all of the embodiments described with reference to FIGS. 1 to 15 will be described with reference to the drawings.

16 is a diagram showing the configuration of a transmitting terminal 1700 according to another embodiment.

Referring to FIG. 16, a transmission terminal 1600 according to another embodiment includes a control unit 1610, a transmission unit 1620, and a reception unit 1630.

The control unit 1610 controls the overall operation of the transmitting terminal 1600 according to a method of transmitting a reference signal to obtain sidelink channel state information by the transmitting terminal required for carrying out the above-described present invention. The transmitter 1620 transmits uplink control information, data, and messages to a base station through a corresponding channel, and transmits sidelink control information, data, and messages to a receiving terminal through a corresponding channel. The receiving unit 1630 receives downlink control information, data, and messages from a base station through a corresponding channel, and receives sidelink control information, data, and messages from a receiving terminal through a corresponding channel.

In order to obtain sidelink channel state information between the transmitting terminal and the receiving terminal, the transmitting unit 1620 may transmit the SL CSI-RS to the receiving terminal. The receiving terminal may be configured to calculate channel state information based on the received SL CSI-RS and to perform CSI reporting through the PSFCH.

Therefore, in order to obtain sidelink CSI, CSI reporting must be enabled for the receiving terminal. According to an example, CSI reporting may be activated by a higher layer parameter. The receiver 1620 may receive information on whether CSI reporting is activated through higher layer signaling.

The controller 1610 may determine whether to transmit the sidelink channel state information reference signal SL CSI-RS based on the activation information of CSI reporting. According to an example, the transmitting terminal may be configured to transmit the SL CSI-RS to the receiving terminal when CSI reporting is activated. The controller 1610 may determine whether to transmit the SL CSI-RS to the receiving terminal in which CSI reporting is activated. The transmitter 1620 may transmit whether or not to transmit the SL CSI-RS to the receiving terminal through the SCI format.

According to an example, when transmitting any PSSCH, whether or not to transmit SL CSI-RS may be dynamically indicated. That is, when transmitting a PSSCH for an arbitrary receiving terminal, an information region for indicating whether to transmit a CSI-RS through a DCI format or an SCI format for transmitting the corresponding PSSCH allocation information is defined, and based on this, the corresponding PSSCH transmission is CSI -It can indicate whether RS transmission is included.

That is, the controller 1610 may set a predetermined information area included in the SCI format, for example, a value of the CSI request field, according to whether or not the determined SL CSI-RS is transmitted. The receiving terminal may receive the SL CSI-RS according to the value of the CSI request field included in the received SCI format.

The transmitter 1620 may transmit the SL CSI-RS to the receiving terminal within the resources allocated for PSSCH transmission. When the control unit 1610 determines that the SL CSI-RS is to be transmitted, the transmitter 1620 may transmit the SL CSI-RS to the receiving terminal within the resources allocated for PSSCH transmission. To this end, an SL CSI-RS that can be used for obtaining channel state information may be configured by a base station, a transmitting terminal, or a scheduling terminal, and configuration information for the SL CSI-RS may be transmitted to the receiving terminal.

According to an example, for transmission of SL CSI-RS, a first symbol in a resource block used for transmission of SL CSI-RS and frequency resource allocation information may be configured through a higher layer parameter. The transmitter 1620 is based on the first symbol and frequency resource allocation information in the resource block used for transmission of the SL CSI-RS configured by higher layer signaling within the resources allocated for PSSCH transmission for the corresponding receiving terminal, the SL CSI -RS can be transmitted to the receiving terminal.

The receiving terminal may receive the SL CSI-RS, obtain channel state information based on the received SL CSI-RS, and report the CSI through the PSFCH. For this, according to an example, PSFCH resource allocation information may be dynamically indicated through DCI or SCI including resource allocation information for PSSCH transmitted through PDCCH or PSCCH from a base station, a transmitting terminal, or a scheduling terminal. For example, a PSFCH resource indication information region for CSI reporting of a receiving terminal may be included in the DCI format or the SCI format. Through this, the PSFCH resource for CSI reporting of the receiving terminal may be determined.

When the receiving terminal performs CSI reporting through the determined PSFCH resource, the receiving unit 1630 may perform CSI acquisition.

Alternatively, when the corresponding CSI reporting is performed through a higher layer message, the receiving terminal transmits the PSSCH to the transmitting terminal for CSI reporting, and the receiving unit 1630 may perform CSI acquisition through the corresponding PSSCH.

Accordingly, it is possible to provide a method and apparatus for transmitting and receiving a reference signal between a transmitting terminal and a receiving terminal in order to obtain channel state information for sidelink transmission in the NR.

17 is a diagram showing the configuration of a receiving terminal 1700 according to another embodiment.

Referring to FIG. 17, a receiving terminal 1700 according to another embodiment includes a control unit 1710, a transmitting unit 1720, and a receiving unit 1730.

The control unit 1710 controls the overall operation of the receiving terminal 1700 according to a method in which the receiving terminal required for carrying out the above-described present invention receives a reference signal to obtain sidelink channel state information. The transmission unit 1720 and the reception unit 1730 are used to transmit and receive signals, messages, and data necessary for carrying out the above-described present invention with the terminal.

The receiving unit 1730 may receive the SL CSI-RS from the transmitting terminal, for which transmission or not to be transmitted is determined based on activation information of CSI reporting within the resources allocated for PSSCH transmission.

In order to obtain sidelink channel state information between the transmitting terminal and the receiving terminal, the receiving unit 1730 may receive the SL CSI-RS from the transmitting terminal. The receiving terminal may be configured to calculate channel state information based on the received SL CSI-RS and to perform CSI reporting through the PSFCH.

Therefore, in order to obtain sidelink CSI, CSI reporting must be enabled for the receiving terminal. According to an example, CSI reporting may be activated by a higher layer parameter. The transmitting terminal may receive information on whether or not CSI reporting is activated through higher layer signaling.

The transmitting terminal may determine whether to transmit the SL CSI-RS based on the activation information of CSI reporting. According to an example, the transmitting terminal may be configured to transmit the SL CSI-RS to the receiving terminal when CSI reporting is activated. When the transmitting terminal determines whether to transmit the SL CSI-RS to the receiving terminal for which CSI reporting is activated, the receiving unit 1730 may receive whether to transmit the SL CSI-RS from the transmitting terminal through the SCI format.

According to an example, when transmitting any PSSCH, whether or not to transmit SL CSI-RS may be dynamically indicated. That is, when transmitting a PSSCH for an arbitrary receiving terminal, an information region for indicating whether to transmit a CSI-RS through a DCI format or an SCI format for transmitting the corresponding PSSCH allocation information is defined, and based on this, the corresponding PSSCH transmission is CSI -It can indicate whether RS transmission is included.

That is, the transmitting terminal may set a predetermined information area included in the SCI format, for example, a value of the CSI request field, according to whether or not the determined SL CSI-RS is transmitted. The receiver 1730 may receive the SL CSI-RS according to the value of the CSI request field included in the received SCI format.

The receiver 1730 may receive the SL CSI-RS from the transmitting terminal within the resources allocated for PSSCH reception. When the transmitting terminal determines to transmit the SL CSI-RS, the receiving terminal may receive the SL CSI-RS from the transmitting terminal within resources allocated for PSSCH transmission. To this end, an SL CSI-RS that can be used for obtaining channel state information may be set by a base station, a transmitting terminal, or a scheduling terminal, and configuration information for the SL CSI-RS may be received by the receiving unit 1730.

According to an example, for transmission of SL CSI-RS, a first symbol in a resource block used for transmission of SL CSI-RS and frequency resource allocation information may be configured through a higher layer parameter. The receiver 1730 is based on the first symbol in the resource block used for transmission of the SL CSI-RS configured by higher layer signaling and the frequency resource allocation information, within the resources allocated for PSSCH reception for the corresponding receiving terminal, the SL CSI -RS can be received from the transmitting terminal.

The transmitter 1720 may perform CSI reporting based on the received SL CSI-RS. When the SL CSI-RS is received, the controller 1710 may acquire channel state information based on the received SL CSI-RS. The transmitter 1720 may report CSI through PSFCH. For this, according to an example, PSFCH resource allocation information may be dynamically indicated through DCI or SCI including resource allocation information for PSSCH transmitted through PDCCH or PSCCH from a base station, a transmitting terminal, or a scheduling terminal.

For example, a PSFCH resource indication information region for CSI reporting of a receiving terminal may be included in the DCI format or the SCI format. Through this, the PSFCH resource for CSI reporting of the receiving terminal may be determined.

When the transmission unit 1720 performs CSI reporting through the determined PSFCH resource, CSI may be obtained in the transmitting terminal.

Or, when the corresponding CSI reporting is performed through a higher layer message, the receiving terminal transmits the PSSCH to the transmitting terminal for CSI reporting, and the transmitting unit 1720 reports CSI through the PSSCH determined by the base station or determined by the control unit 1710. By performing, CSI can be obtained in the transmitting terminal.

Accordingly, it is possible to provide a method and apparatus for transmitting and receiving a reference signal between a transmitting terminal and a receiving terminal in order to obtain channel state information for sidelink transmission in the NR.

The above-described embodiments may be supported by standard documents disclosed in at least one of IEEE 802, 3GPP and 3GPP2 wireless access systems. That is, steps, configurations, and parts not described in order to clearly reveal the present technical idea among the embodiments may be supported by the aforementioned standard documents. In addition, all terms disclosed in the present specification can be described by the standard documents disclosed above.

The above-described embodiments can be implemented through various means. For example, the present embodiments may be implemented by hardware, firmware, software, or a combination thereof.

In the case of implementation by hardware, the method according to the embodiments includes one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), and FPGAs. (Field Programmable Gate Arrays), a processor, a controller, a microcontroller, or a microprocessor.

In the case of implementation by firmware or software, the method according to the embodiments may be implemented in the form of an apparatus, procedure, or function that performs the functions or operations described above. The software code may be stored in a memory unit and driven by a processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor through various known means.

In addition, terms such as "system", "processor", "controller", "component", "module", "interface", "model", or "unit" described above generally refer to computer-related entity hardware, hardware and software. It may mean a combination of, software or running software. For example, the above-described components may be, but are not limited to, a process driven by a processor, a processor, a controller, a control processor, an object, an execution thread, a program, and/or a computer. For example, an application running on a controller or processor and a controller or processor can both be components. One or more components may reside within a process and/or thread of execution, and the components may be located on one device (eg, a system, a computing device, etc.) or distributed across two or more devices.

The above description is merely illustrative of the technical idea of the present disclosure, and those of ordinary skill in the technical field to which the present disclosure pertains will be able to make various modifications and variations without departing from the essential characteristics of the technical idea. In addition, the present embodiments are not intended to limit the technical idea of the present disclosure, but to explain the technical idea, and thus the scope of the technical idea is not limited by these embodiments. The scope of protection of the present disclosure should be construed by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present disclosure.

Claims (16)

In a method for a transmitting terminal to transmit a reference signal to obtain sidelink channel state information,
Receiving activation information for reporting sidelink channel state information (CSI);
Determining whether to transmit a sidelink channel state information reference signal (SL CSI-RS) based on the activation information of the CSI reporting; And
A method comprising the step of transmitting the SL CSI-RS to a receiving terminal within a resource allocated to a sidelink data channel (Physical Sidelink Shared Channel; PSSCH) transmission. The method of claim 1,
Whether the SL CSI-RS is transmitted,
A method indicated by the value of the CSI request field included in the Sidelink Control Information format (SCI format). The method of claim 1,
The activation information of the CSI reporting,
Method received by higher layer signaling. The method of claim 1,
The SL CSI-RS,
A method of transmitting based on frequency resource allocation information and a first symbol in a resource block used for transmission of the SL CSI-RS configured by higher layer signaling within the resource allocated to the PSSCH transmission. In the method for receiving a reference signal to obtain sidelink channel state information by a receiving terminal,
Sidelink Channel State Information Reference Signal (SL CSI), in which transmission or not is determined based on activation information of CSI reporting, within resources allocated for sidelink data channel (Physical Sidelink Shared Channel; PSSCH) transmission. -Receiving an RS) from a transmitting terminal; And
And performing CSI reporting based on the received SL CSI-RS. The method of claim 5,
Whether the SL CSI-RS is transmitted,
A method indicated by the value of the CSI request field included in the Sidelink Control Information format (SCI format). The method of claim 5,
The activation information of the CSI reporting,
Method received by higher layer signaling. The method of claim 5,
The SL CSI-RS,
A method of receiving based on frequency resource allocation information and a first symbol in a resource block used for transmission of the SL CSI-RS configured by higher layer signaling within the resource allocated to the PSSCH transmission. In the transmitting terminal transmitting a reference signal to obtain sidelink channel state information,
A receiver configured to receive activation information for sidelink channel state information (CSI) reporting;
A control unit for determining whether to transmit a sidelink channel state information reference signal (SL CSI-RS) based on the activation information of the CSI reporting; And
A terminal comprising a transmitter for transmitting the SL CSI-RS to a receiving terminal within a resource allocated for transmission of a physical sidelink data channel (PSSCH). The method of claim 9,
Whether the SL CSI-RS is transmitted,
A terminal indicated by a value of a CSI request field included in a sidelink control information format (SCI format). The method of claim 9,
The activation information of the CSI reporting,
A terminal received by higher layer signaling. The method of claim 9,
The SL CSI-RS,
In the resource allocated to the PSSCH transmission, the terminal is transmitted based on the frequency resource allocation information and the first symbol in the resource block used for transmission of the SL CSI-RS configured by higher layer signaling. In the receiving terminal receiving a reference signal to obtain sidelink channel state information,
Sidelink Channel State Information Reference Signal (SL CSI), in which transmission or not is determined based on activation information of CSI reporting, within resources allocated for sidelink data channel (Physical Sidelink Shared Channel; PSSCH) transmission. -RS) receiving unit for receiving from the transmitting terminal; And
Terminal comprising a transmitter for performing CSI reporting on the basis of the received SL CSI-RS. The method of claim 13,
Whether the SL CSI-RS is transmitted,
A terminal indicated by a value of a CSI request field included in a sidelink control information format (SCI format). The method of claim 13,
The activation information of the CSI reporting,
A terminal received by higher layer signaling. The method of claim 13,
The SL CSI-RS,
A terminal received based on frequency resource allocation information and a first symbol in a resource block used for transmission of the SL CSI-RS configured by higher layer signaling within the resource allocated to the PSSCH transmission.

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