KR20200127123A - Method and apparatus for transmitting and receiving sidelink harq feedback information - Google Patents

Abstract

The present embodiments relate to a method and apparatus for transmitting and receiving sidelink HARQ feedback information. According to an embodiment of the present invention, a method of transmitting HARQ feedback information for sidelink transmission by a terminal comprises the steps of: receiving configuration information for a resource pool for sidelink transmission; generating a signal for transmitting HARQ feedback information for a sidelink data channel (physical sidelink shared channel (PSSCH)) received from another terminal based on a sequence associated with the resource pool; and transmitting a signal generated through a physical sidelink feedback channel (PSFCH) in the resource pool.

Description

Method and apparatus for transmitting and receiving sidelink HARQ feedback information {METHOD AND APPARATUS FOR TRANSMITTING AND RECEIVING SIDELINK HARQ FEEDBACK INFORMATION}

The present embodiments propose a method and apparatus for transmitting and receiving sidelink HARQ feedback 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 generating a signal for transmitting HARQ ACK/NACK feedback information for NR sidelink transmission is required, that is, a sidelink, which is a radio link between terminals for providing V2X service in NR. Is done.

Embodiments of the present disclosure may provide a specific method and apparatus capable of generating a signal transmitted through PSFCH in order to transmit HARQ feedback information for sidelink transmission in NR.

In one aspect, in the present embodiments, in a method for a terminal to transmit HARQ feedback information for sidelink transmission, receiving configuration information for a resource pool for sidelink transmission, a sequence associated with a resource pool On the basis of (sequence), generating a signal for transmitting HARQ feedback information for a sidelink data channel (Physical Sidelink Shared Channel (PSSCH)) received from another terminal and a sidelink feedback channel in the resource pool (Physical Sidelink Feedback) A method including transmitting a signal generated through a channel (PSFCH) may be provided.

In another aspect, in the present embodiments, in a method for a base station to control transmission of HARQ feedback information for sidelink transmission of a terminal, the step of transmitting configuration information for a resource pool for sidelink transmission and resources Including the step of transmitting configuration information for the sidelink feedback channel (Physical Sidelink Feedback Channel; PSFCH) resources in the pool, the terminal, based on a sequence associated with the resource pool, the sidelink received from the other terminal A method of generating a signal for transmitting HARQ feedback information for a data channel (Physical Sidelink Shared Channel; PSSCH) and transmitting the generated signal through PSFCH may be provided.

In another aspect, the present embodiments are in the terminal for transmitting HARQ feedback information for sidelink transmission, a receiving unit for receiving configuration information for a resource pool for sidelink transmission, a sequence associated with the resource pool ( sequence), a control unit that generates a signal for transmitting HARQ feedback information for a sidelink data channel (PSSCH) received from another terminal, and a physical sidelink feedback channel in the resource pool. It can provide a terminal including a transmitter for transmitting a signal generated through the; PSFCH).

In another aspect, the present embodiments are in a base station that controls transmission of HARQ feedback information for sidelink transmission of a terminal, and transmits configuration information on a resource pool for sidelink transmission, and In the sidelink feedback channel (Physical Sidelink Feedback Channel; PSFCH) includes a transmitter for transmitting configuration information for the resource, the terminal, based on a sequence associated with the resource pool, the sidelink data channel received from another terminal It is possible to provide a base station that generates a signal for transmitting HARQ feedback information for (Physical Sidelink Shared Channel; PSSCH) and transmits the generated signal through the PSFCH.

According to the present embodiments, it is possible to provide a specific method and apparatus for generating a signal transmitted through PSFCH in order to transmit HARQ feedback 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 terminal to transmit HARQ feedback information for sidelink transmission according to an embodiment.
15 is a diagram illustrating a procedure for a base station to control transmission of HARQ feedback information for sidelink transmission of a terminal according to an embodiment.
16 is a diagram for explaining an example of a PSFCH set for each PSCCH set in RBG units within a resource pool according to an embodiment.
17 is a diagram for explaining an example of a PSFCH in which a period is defined as 4 according to an embodiment.
18 is a diagram showing a configuration of a terminal according to another embodiment.
19 is a diagram showing a configuration of a base station 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 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 by dividing into 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 a technology to improve the performance of the sidelink technology developed based on the conventional D2D communication according to the requirements of V2X has been progressed. 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, in C-V2X, there are a method in which a base station intervenes in resource selection and management (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 the PSSCH associated with the 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) are activated to be used for transmission/reception of uplink/downlink data. 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. .

HARQ ACK/NACK feedback resource allocation method

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

On the other hand, in the conventional 3GPP LTE, a sidelink transmission/reception method for supporting V2X communication, a concept that combines D2D, which is communication between terminals, and V2V, which is an extended form of communication between vehicles, and V2I, which is communication between vehicle and base stations It is standardized as an additional feature. In more detail, D2D is a service scenario that assumes communication between existing terminals having a mutually equivalent relationship, and V2V is an extended communication service scenario between terminals that assumes a wireless communication environment between general pedestrians and vehicle terminals having different characteristics. In order to successfully use radio resources with or without assistance from a base station, various technologies are largely standardized in initial access and resource allocation.

In NR, studies for standardization related to V2X in line with sidelink support and changed service requirements are in progress, and four new service scenarios are largely assumed as follows.

Vehicles Platooning allows vehicles to dynamically form a platoon that moves together. All vehicles in the platoon obtain information from the leading vehicle to manage the platoon. This information allows vehicles to drive closer than normal and move together in the same direction in a coordinated manner.

Extended Sensors allow the exchange of raw or processed data collected through local sensors or live video images between vehicles, road site devices, pedestrian devices and V2X application servers. do. Vehicles can increase their awareness of the environment beyond what their sensors can detect, and can have a broader and more holistic view of the local situation. The high data rate is one of its main features.

Advanced Driving enables semi-automatic or fully automatic driving. Each vehicle and/or RSU shares own perception data obtained from local sensors with nearby vehicles and allows the vehicle to synchronize and adjust trajectories or manoeuvres. Each vehicle shares a driving intention with a nearby driving vehicle.

Remote Driving allows remote drivers or V2X applications to drive remote vehicles for vehicles in hazardous environments or for passengers who cannot drive independently. For example, when the variation is limited and the routes are predictable, such as public transportation, driving based on cloud computing may be used. In this case, high reliability and low latency are the main requirements.

On the other hand, in NR V2X, it was tentatively agreed to support the transmission method of Mode 1, in which the base station manages communication resources between terminals, and Mode 2, in which communication resources are managed by communication between terminals. In particular, Mode 2 is as follows. Branch transmission types were agreed and each was expressed as Mode 2-(a) ~ Mode 2-(d) or Mode 2a ~ Mode 2d.

Mode-2a: The UE autonomously selects sidelink resources for transmission (UE autonomously selects sidelink resource for transmission).

Mode-2b: The UE supports sidelink resource selection for other UEs (UE assists sidelink resource selection for other UE(s)).

Mode-2c: The UE is configured with a grant (like type-1) configured with NR for sidelink transmission (UE is configured with NR configured grant (type-1 like) for sidelink transmission).

Mode-2d: The UE schedules sidelink transmissions of other UEs (UE schedules sidelink transmissions of other UEs).

However, afterwards, mode 2b, which transmits channel setting assistant information, was agreed as an additional function of the remaining three modes, and it was agreed not to operate in a single mode. Also, for Mode-2d, Rel. It was agreed not to introduce it into 16 features.

In the case of the existing LTE, when the base station manages communication resources between terminals, the modes are divided into Mode 1 and Mode 3, and when the terminal autonomously manages communication resources, the modes are divided into Mode 2 and Mode 4. The sidelink transmission procedure in LTE Mode 1 is as follows.

1) The base station sets a resource pool for transmission of the PSCCH to all terminals. The pool is divided into a region consisting of two subframes and 1RB bandwidth (1x4 = 4RB in total), and an index consisting of 6 bits is allocated to each region. At this time, the index is allocated only to the upper half band of the resource pool, and all sidelink terminals repeatedly transmit the same SCI at the same location in the lower half band (total 8RB).

2) When the terminal posts a scheduling request (SR) to the base station through the PUCCH, the base station lowers the 6-bit PSCCH index and time/frequency resource information of the data domain through the PDCCH in DCI Format 5.

3) The terminal transmits the SCI format 0 message through the PSCCH resource indicated by 6 bits based on the received information. At this time, the data area resource inside the message uses the information received in DCI Format 5. In addition, the UE encodes the data to be transmitted using an MCS value selected by itself or preset by RRC, and then maps and transmits the data region resource.

4) Other terminals continuously search the inside of the resource pool for transmission of the PSCCH, and when the PSCCH transmitted by the desired user is detected, it detects the data region resource location and MCS based on the corresponding SCI message to perform sidelink reception.

The sidelink transmission procedure of LTE Mode 2 is as follows.

1) The base station sets a resource pool for PSCCH transmission in Mode 2 to all terminals. The structure of the pool is the same as that set in Mode 1.

2) After checking whether a specific PSCCH resource region is used through sensing, the UE transmits an SCI format 0 message indicating an empty PSSCH resource region through sensing if it is empty. At this time, the data area resource in the message follows the resource area set by itself. In addition, the terminal encodes the data to be transmitted using the MCS value selected by the terminal, and then maps and transmits the data region resource.

3) The procedure for other terminals to perform the region reception is the same as in Mode 1.

The sidelink transmission procedure of LTE Mode 3 is as follows.

1) The base station sets a resource pool for transmission of the PSCCH to all terminals. In this case, the PSCCH may be configured to be connected (adjacent) to the PSSCH indicated by the PSCCH or may be independently configured. When independently configured, it is similar to LTE Mode 1, and only the corresponding resource pool is divided into one subframe and two consecutive RB regions (2x2 = 4RB in total), and an index consisting of k bits is allocated to each region. Here, k varies according to the bandwidth size of the set resource pool. When the PSCCH and the PSSCH indicated by it are configured to be connected, the bandwidth of the configured resource pool is frequency-divided into subchannels having a preset RB unit size of at least 4, and the bottom two RBs of each subchannel are assigned to the PSCCH transmission candidate region. (2x2 = 4RB in total) an index consisting of k bits is allocated. Here, k varies depending on the bandwidth of the set resource pool, that is, the number of subchannels. In the case of Mode 3, SCI is not repeatedly transmitted.

2) When the UE sends a scheduling request (SR) to the base station through the PUCCH, the base station lowers the k-bit PSCCH index and time/frequency resource information of the data region through the PDCCH in DCI Format 5.

3) The UE transmits the SCI format 1 message through the PSCCH resource indicated by k bits based on the received information. At this time, the data area resource inside the message uses the information received in DCI Format 5A. Then, the data to be sent is mapped to the corresponding data area resource and transmitted.

4) Subsequent procedures are the same as in Mode 1.

Sidelink transmission procedure of LTE Mode 4 Basically, the resource pool type is the same as that of Mode 3, and the transmission method is the same as that of Mode 2. However, a message to reserve a resource by setting a specific time resource and a priority message to manage QoS are additionally included in the SCI.

Meanwhile, in NR V2X, in the case of NR-based V2X, a need for supporting sidelink transmission/reception based on unicast or groupcast as well as the above-described broadcast has been raised. As described above, when a unicast or groupcast-based sidelink transmission/reception method is defined as a form of NR-based V2X communication, it is necessary to define a HARQ application method for a corresponding sidelink radio channel. The HARQ ACK/NACK message for a specific message may be transmitted through a physical sidelink feedback channel (PSFCH). In this case, the last symbol(s) of the slot may be used as the location of the corresponding PSFCH. In this manner, it has been agreed that a PSFCH region is defined for every slot and for N greater than 1, for every N slot, and it has been agreed to support at least one of N greater than 1. However, a specific indication method, a resource region other than the last symbol, and a method of transmitting a feedback message excluding HARQ have not been discussed yet.

In this way, when the PSFCH is allocated to the last symbol(s) of the slot, the terminal using the slot for data transmission must perform transmission except for the resource region used as the PSFCH. However, in the current procedure, only the first transmitting terminal and the terminal receiving the block are the only terminals that can know that such PSFCH transmission will be made, so when other terminals attempt to use the corresponding resource region, a resource conflict problem between the PSSCH region and the PSFCH region may occur have.

In addition, in the case of the sidelink, the synchronization between a signal transmitted by each terminal and a signal received by each other terminal is not exactly matched with a transmission/reception signal between a base station and a terminal. This causes a time error of received signals of different terminals to occur at the OFDM symbol level. Accordingly, multiplexed transmission/reception based on a digital orthogonal signal based on a sequence used in conventional communications may have severe interference and thus seriously deteriorate reception performance.

Accordingly, the present disclosure provides a method of allowing other terminals to know a slot in which a PSFCH region used by a certain terminal exists in an NR sidelink transmission/reception environment. In particular, it provides a method of operating a resource pool in which the PSFCH region is preset and a method of dynamically transmitting corresponding information through DCI/SCI when scheduling-based resource configuration is performed in such an environment.

In addition, the present disclosure provides a method of generating a signal transmitted and received through a PSFCH region in an NR sidelink transmission/reception environment. In particular, we provide a signal generation method based on the Zadoff-Chu sequence for feedback message transmission. It also provides a method of setting parameters for transmission and reception of the corresponding signal.

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 transmitter UE (Tx UE) refers to a UE that transmits a PSCCH and a PSSCH corresponding thereto to a receiving UE through a sidelink. In addition, a receiver UE (Rx UE) refers to a UE that receives a PSCCH and a PSSCH corresponding thereto from a transmitting UE through a sidelink.

14 is a diagram illustrating a procedure for a terminal to transmit HARQ feedback information for sidelink transmission according to an embodiment.

Referring to FIG. 14, the terminal may receive configuration information on a resource pool for sidelink transmission (S1400).

The base station may configure a resource pool on radio resources for sidelink transmission and reception between the terminal and other terminals. Here, the resource pool may be a radio resource configured to be used to transmit/receive a PSCCH, a PSSCH, or the like between a terminal and another terminal. The terminal may receive configuration information on the resource pool from the base station through higher layer signaling.

According to an example, hereinafter, the base station configures a resource pool for the sidelink and describes on the premise of mode 2 in which radio resources are managed through communication between terminals, but unless contrary to the technical idea, the base station is The same may be applied to the case based on mode 1, which performs scheduling for transmission.

Referring back to FIG. 14, the terminal generates a signal for transmitting HARQ feedback information for a sidelink data channel (Physical Sidelink Shared Channel; PSSCH) received from another terminal based on a sequence associated with the resource pool. It can be done (S1410).

When a PSSCH is received, the UE may be configured to transmit HARQ ACK/NACK feedback information corresponding to the received PSSCH to the UE transmitting the PSSCH. Accordingly, the UE can configure HARQ ACK/NACK feedback information corresponding to the received PSSCH. According to an example, whether HARQ feedback information is transmitted may be indicated by sidelink control information (SCI) including scheduling information for PSSCH. That is, information indicating HARQ feedback information may be transmitted together in the SCI including resource allocation information for PSSCH transmission.

The terminal may use a sequence associated with a resource pool for sidelink transmission in order to generate a signal for transmitting the configured HARQ feedback information. According to an example, the configuration information on the resource pool received from the base station may include information on a sequence preconfigured for the corresponding resource pool.

When the UE generates a signal for transmitting HARQ feedback information using a sequence associated with a resource pool, a predetermined cyclic shift value may be applied to minimize interference with each other. That is, applying the cyclic shift in the time domain is to apply a linear phase rotation in the frequency domain, and signals generated through this are orthogonal to each other so that interference can be minimized.

For example, when many signals are overlapped, the noise of the sum of the interference signals becomes large enough to be negligible, so in an environment where interference control is important, a different cyclic shift may be applied for each terminal for a specific sequence so that the correlation characteristic becomes 0. .

All UEs sharing the PSFCH resource have a common symbol length and sequence number value depending on a preset value. In this case, according to an example, a possible cyclic shift value may depend on the length of the sequence. For example, if the length of the sequence is 12, 12 types of cyclic shift values may be used. In addition, according to an example, when HARQ feedback information configured in each terminal is ACK/NACK, allocation according to each may be possible.

That is, according to an example, the cyclic shift value may be applied to the sequence based on at least one of an ID of a terminal, an ID of another terminal, or a value of HARQ feedback information for a PSSCH. For example, the ID of the receiving terminal receiving the PSSCH may be indicated by a higher layer. The ID of another terminal that has transmitted the PSSCH may be provided by SCI including scheduling information for the PSSCH. That is, a separate cyclic shift may be determined based on a case in which HARQ feedback information for PSSCH reception at each UE is ACK and NACK in addition to ID information of UEs transmitting and receiving PSSCH.

Referring back to FIG. 14, the terminal may transmit a signal generated through a physical sidelink feedback channel (PSFCH) in the resource pool (S1420).

According to an example, a PSFCH resource that can be used when transmitting a PSFCH may be indicated within a resource pool for sidelink transmission configured between a terminal and another terminal. In this case, in addition to the PSCCH region and the PSSCH region, a PSFCH region may exist in the resource pool. In particular, the UE may receive configuration information on a frequency resource through which a PSFCH can be transmitted within a resource pool.

According to an example, a frequency resource for transmission of the PSFCH may be configured as a set of physical resource blocks (PRBs) in a resource pool for sidelink transmission. In this case, configuration information on frequency resources for transmission of PSFCH may be received by higher layer signaling.

In general, since the PSFCH is required to correspond to each of one transport block, it is not necessary to set a transmission zone for every RB. That is, at the time of initial transmission, the PSFCH is set to be transmitted only at a location corresponding to one PSCCH transmission region, and a terminal performing transmission through the remaining slots in which the corresponding region exists can perform transmission with the corresponding region empty. have. In this case, the symbol length of the PSFCH is set through RRC information other than the initial resource pool resource setting, and resource allocation of the resource pool may be determined through this.

The UE is based on the number of subchannels for the resource pool and the number of PSSCH slots associated with the PSFCH slot, one of the PSFCH used to transmit HARQ feedback information among the set of PRBs based on the configuration information for the frequency resource in the resource pool. The above PRB can be determined. In addition, the terminal may determine the number of PSFCH resources used to transmit HARQ feedback information.

In addition, transmission of the HARQ feedback information may be performed based on timing gap information between reception of the PSSCH and transmission of HARQ feedback information for reception of the PSSCH, received through higher layer signaling. In this case, according to an example, PSFCH transmission may be performed in a first slot including a PSFCH resource in a resource pool after the last slot of PSSCH reception.

Accordingly, the UE may transmit a signal generated for HARQ feedback information for the received PSSCH through the PSFCH resource determined from the resource pool.

Accordingly, it is possible to provide a specific method and apparatus capable of generating a signal transmitted through PSFCH in order to transmit HARQ feedback information for sidelink transmission in NR.

15 is a diagram illustrating a procedure for a base station to control transmission of HARQ feedback information for sidelink transmission of a terminal according to an embodiment.

Referring to FIG. 15, the base station may transmit configuration information on a resource pool for sidelink transmission (S1500).

The base station may configure a resource pool on radio resources for sidelink transmission and reception between the terminal and other terminals. Here, the resource pool may be a radio resource configured to be used to transmit/receive a PSCCH, a PSSCH, or the like between a terminal and another terminal. The base station may transmit configuration information on the resource pool to the terminal through higher layer signaling.

Referring back to FIG. 15, the base station may transmit configuration information for a physical sidelink feedback channel (PSFCH) resource within a resource pool (S1510).

According to an example, a PSFCH resource that can be used when transmitting a PSFCH may be indicated within a resource pool for sidelink transmission configured between a terminal and another terminal. In this case, in addition to the PSCCH region and the PSSCH region, a PSFCH region may exist in the resource pool. In particular, the UE may receive configuration information on a frequency resource through which a PSFCH can be transmitted within a resource pool.

According to an example, the frequency resource for PSFCH transmission may be configured as a set of PRBs in a resource pool for sidelink transmission. In this case, configuration information on frequency resources for PSFCH transmission may be received by higher layer signaling.

In general, since the PSFCH is required to correspond to each of one transport block, it is not necessary to set a transmission zone for every RB. That is, at the time of initial transmission, the PSFCH is set to be transmitted only at a location corresponding to one PSCCH transmission region, and a terminal performing transmission through the remaining slots in which the corresponding region exists can perform transmission with the corresponding region empty. have. In this case, the symbol length of the PSFCH is set through RRC information other than the initial resource pool resource setting, and resource allocation of the resource pool may be determined through this.

The UE is based on the number of subchannels for the resource pool and the number of PSSCH slots associated with the PSFCH slot, one of the PSFCH used to transmit HARQ feedback information among the set of PRBs based on the configuration information for the frequency resource in the resource pool. The above PRB can be determined. In addition, the terminal may determine the number of PSFCH resources used to transmit HARQ feedback information.

When a PSSCH is received, the UE may be configured to transmit HARQ ACK/NACK feedback information corresponding to the received PSSCH to the UE transmitting the PSSCH. Accordingly, the UE can configure HARQ ACK/NACK feedback information corresponding to the received PSSCH. According to an example, whether to transmit HARQ feedback information may be indicated by SCI including scheduling information for PSSCH. That is, information indicating HARQ feedback information may be transmitted together in the SCI including resource allocation information for PSSCH transmission.

The terminal may use a sequence associated with a resource pool for sidelink transmission in order to generate a signal for transmitting the configured HARQ feedback information. According to an example, the configuration information on the resource pool received from the base station may include information on a sequence preconfigured for the corresponding resource pool.

When generating a signal for transmitting HARQ feedback information using a sequence associated with a resource pool, the UE may apply a predetermined cyclic shift value to minimize interference with each other. Signals generated through this may be orthogonal to each other and may be generated to minimize interference.

For example, when many signals are overlapped, the noise of the sum of the interference signals becomes large enough to be negligible, so in an environment where interference control is important, a different cyclic shift may be applied for each terminal for a specific sequence so that the correlation characteristic becomes 0. .

All UEs sharing the PSFCH resource have a common symbol length and sequence number value depending on a preset value. According to an example, when HARQ feedback information configured in each terminal is ACK/NACK, allocation according to each may be possible.

That is, according to an example, the cyclic shift value may be applied to the sequence based on at least one of an ID of a terminal, an ID of another terminal, or a value of HARQ feedback information for a PSSCH. For example, the ID of the receiving terminal receiving the PSSCH may be indicated by a higher layer. The ID of another terminal that has transmitted the PSSCH may be provided by SCI including scheduling information for the PSSCH. That is, a separate cyclic shift may be determined based on a case in which HARQ feedback information for PSSCH reception at each UE is ACK and NACK in addition to ID information of UEs transmitting and receiving PSSCH.

Accordingly, the UE may transmit a signal generated for HARQ feedback information for the received PSSCH through the PSFCH resource determined from the resource pool. In this case, according to an example, transmission of HARQ feedback information may be performed based on timing gap information between reception of PSSCH and transmission of HARQ feedback information for reception of PSSCH, received through higher layer signaling. For example, PSFCH transmission may be performed in a first slot including a PSFCH resource in a resource pool after the last slot of PSSCH reception.

Accordingly, it is possible to provide a specific method and apparatus capable of generating a signal transmitted through PSFCH in order to transmit HARQ feedback information for sidelink transmission in NR.

Hereinafter, with reference to the related drawings, each embodiment related to the allocation of radio resources for transmitting HARQ feedback information for sidelink transmission in NR and generation of a signal for transmitting HARQ feedback information will be described in detail. do.

The present disclosure largely provides (1) a method of generating a signal transmitted through a PSFCH, and (2) a method of setting a parameter for generating a PSFCH message. 16 illustrates a PSCCH-PSSCH-PSFCH multiplexing structure assumed in the present disclosure. This shows the slot in which the PSFCH exists, and the PSFCH and the GP+AGC associated therewith may not exist in all slots. The resource block group (RBG) in FIG. 16 does not mean 12 resource blocks (RB) in a general NR, but refers to the minimum bandwidth in which one terminal can transmit when setting a resource pool. . The bandwidth management structure in the resource pool shown in FIG. 16 is an example, and is for convenience of description, and the invention according to the present disclosure is not limited thereto.

Embodiment 1: Generating a signal transmitted through PSFCH

In the present disclosure, a Zadoff-Chu sequence capable of deriving a certain degree of interference improvement performance due to low interference characteristics in a sidelobe even in an environment where a shift between incoming signals is basically generated and orthogonality is not guaranteed is provided to PSFCH. Provides a way to use.

을 사용할 수 있다. 여기서, α는 위상 시프트 값, δ는 사이클릭 시프트 값, u는 심볼 길이, v는 시퀀스 번호일 수 있다.According to an example, the sequence used at this time is defined as a low-PAPR (peak to average power ratio) sequence defined in TS 38.211.

You can use Here, α may be a phase shift value, δ may be a cyclic shift value, u may be a symbol length, and v may be a sequence number.

When the Zadoff-Chu sequence is used in the PSFCH, the following method may be applied. First, different values of α (phase shift) between different terminals are not supported. This is because the timing cannot be guaranteed and the signal must be classified only by the intensity value, not the phase value. Also, make up an empty space for the guard band up and down. For example, even if two RBs are used, the signal is distributed only to REs smaller than 24. A guard period (GP) can be introduced, but automatic gain control (AGC) and reference signal (RS) are not introduced separately because they may have additional interference. Specifically, the following methods can be additionally applied.

However, hereinafter, the description is made on the premise that the Zadoff-Chu sequence is applied, but is not limited thereto. The embodiments described in the present disclosure may be substantially equally applied to sequences other than Zadoff-Chu, unless contrary to the technical idea.

① Use PSFCH with extended CP (cyclic prefix)

In order to be able to support PSFCH transmission/reception that maintains orthogonality in a situation where an error of more than the existing CP occurs due to a large distance between terminals, the base station sets the number of symbols of the PSFCH to a value greater than 1, and sets the corresponding region to CP. I can. As an embodiment, in the case of an environment in which 15 kHz subcarrier spacing (SCS) is used, the CP length c and the symbol length u according to the number of PSFCH symbols s set by the base station may be set as follows.

(1) When s = 1, c = 144Ts = 9216Tc, u = 2048Ts

(2) When s = 2, c = 2336Ts (144+144+2048), u = 2048Ts

(3) When s = 3, c = 4528Ts (144*3+2048*2), u = 2048Ts

If the reception point (RP) uses an extended cyclic prefix (ECP) in 60 kHz SCS, the CP length c and the symbol length u according to the number of PSFCH symbols s set by the base station are set as follows. I can.

(1) When s = 1, c = 128Ts = 8192Tc, u = 512Ts

(2) When s = 2, c =768Ts (128+128+512), u = 512Ts

In this case, since each signal is received in a form having only a phase error under the assumption that the time error between signals is within the CP range, the original orthogonality of Zadoff-Chu can be transmitted and received in an undamaged form.

② Overlapping PSSCH and PSFCH

This method does not perform rate matching by designating a physically separated PSFCH and matching the PSSCH to the designated PSFCH, but by adjusting the transmission power of the symbol of the PSFCH to provide feedback at a preset position in the PSSCH region. This is a method of sending a control message. That is, a PSSCH signal sent by UE A, a PSFCH signal sent by UE B, and a PSFCH signal sent by UE C can be mixed on the same time/frequency resource. However, PSSCHs of different terminals cannot be mixed. In this case, the receiving terminal receiving the PSSCH may treat and receive another signal transmitted through the PSFCH as interference noise, or may remove the corresponding component after attempting to detect the PSFCH. The transmitting terminal may also predict a corresponding situation and perform an operation such as selecting a lower MCS (modulcation coding scheme) level in advance.

For this operation, the transmission power value of the PSFCH may be separately preset. That is, the transmission power value of the PSFCH may be set as a predetermined ratio or difference with the current PSSCH or PSCCH transmission power, or may be set as an explicit value, and only the maximum or minimum value is set and the UE transmits it arbitrarily. You may.

Second embodiment: parameter setting for PSFCH message generation

에서 유저 별로 다른 u를 사용한다.In a general code-based multiplexing environment, the Zadoff-Chu sequence is operated in such a way that the cross-correlation characteristic is limited to less than the square root of the length by using a sequence of different seeds between different terminals. In other words,

Different users use u in.

However, when many signals are overlapped, the noise of the sum of the interfering signals increases to an extent that cannot be ignored, so in an environment where interference control is important, the mutual correlation characteristic is assigned to a cyclic shift of a specific sequence, that is, the terminal A method using different δ may also be used. Specifically, the following method may be applied. For smooth explanation, the PSFCH structure defined as period 4 is described as an example in FIG. 17, but substantially the same method may be applied in all periods.

① Use only single u,v

All UEs that share PSFCH resources have common u and v values depending on a preset value. The possible cyclic shift (δ) value here depends on the length of the sequence Nzc. For example, when Nzc is 12, 12 types of cyclic shift values may be used. In addition, in the case of ACK/NACK of each terminal, allocation according to each is possible. For example, the following assignment is possible. Here, s is a value obtained by taking the number of the slot in which the corresponding PSCCH exists as the remainder of the PSFCH period value, and p is the period of the slot in which the PSFCH exists. In Fig. 17, p=4. k is a positive integer greater than or equal to 1, which is preset or determined depending on p.

, NACK일 때

(또는 그 반대)(1) In case of ACK

, When it is NACK

(Or vice versa)

, NACK일 때

(또는 그 반대) (2) In case of ACK

, When it is NACK

(Or vice versa)

, NACK일 때

(또는 그 반대)(3) In case of ACK

, When it is NACK

(Or vice versa)

, NACK일 때

(또는 ACK일 때

, NACK일 때

)(4) In case of ACK

, When it is NACK

(Or ACK

, When it is NACK

)

For example, assuming that Nzc=12, when method (1) is applied, NACK for PSCCH-PSSCH transmitted through 0th slot is δ=6, PSCCH-PSSCH transmitted through 3rd slot The ACK for is δ=3. When method (2) is applied, the NACK for the PSCCH-PSSCH transmitted through the 0th slot is δ=1, and the ACK for the PSCCH-PSSCH transmitted through the 3rd slot is δ=6. When method (3) is applied, NACK for PSCCH-PSSCH transmitted through 0th slot is δ=1, and ACK for PSCCH-PSSCH transmitted through 3rd slot is δ=9. In addition, when method (4) is applied, the NACK for the PSCCH-PSSCH transmitted through the 0th slot is δ=1, and the ACK for the PSCCH-PSSCH transmitted through the 3rd slot becomes δ=0.

At this time, in the case where the period x 2 value of the slot is greater than Nzc in the method (1), (2), and (3) or the period + 1 value of the slot in the method (4) is greater than Nzc, some slots Only transmissions that cannot use this HARQ can be supported.

② Different users use u and v

This method is a method of using different u and v values according to the terminal ID and setting value, as in the past. In this case, the method provided in the present disclosure is that when PSFCH is applied only to one RBG among a plurality of RBGs, PSCCH terminals having the same time or frequency share the same u and v, and in each case, the same frequency or the same This is a method for allocating the same δ between terminals.

For example, in the case of FIG. 17, if the PSFCH is allocated to only one RBG, the PSFCH for the PDCCH transmitted through the upper RBG is defined as u=0, and the PSFCH for the PDCCH transmitted through the lower RBG is defined as u=1. , δ values can be defined as in the above-described method ①.

Accordingly, it is possible to provide a specific method and apparatus capable of generating a signal transmitted through PSFCH in order to transmit HARQ feedback information for sidelink transmission in NR. Through this method, PSFCH transmission resources can be effectively operated, and a degree of deterioration of feedback transmission performance of other terminals can be reduced through PSFCH transmission.

In addition, in the present disclosure, (1) a method of operating a resource pool in which a PSFCH region is separately defined, and (2) a method of transmitting information about the existence of a PSFCH region through a DCI or SCI region may be further provided.

Hereinafter, the scheduling UE (S-UE) manages sidelink transmission resources between the UEs it manages and allocates to each link based on the SR received from each UE or information received from the upper layer. It refers to a terminal that allocates a transmission resource within a time/frequency resource set in advance by a base station or the like, and delivers it to a transmitter UE of a corresponding link. In addition, the scheduling indication message refers to a message including time/frequency location information of a data region to be used by a transmitting terminal, transmitted by a base station or a scheduling terminal in the form of DCI/SCI. In addition, the sidelink control message refers to a message including the time/frequency and MCS information of the data region, which is transmitted from the sender terminal to the receiver terminal.

Third embodiment: resource pool operation in which the PSFCH region is separately defined

According to an example, the transmittable position of the PSFCH allocated to the last symbols may be predefined within a resource pool. The transmittable position of the PSFCH may be defined together when a resource pool is set through RRC, but may be additionally set in a resource pool designated in advance through a dedicated RRC and may be divided and defined as needed. For example, the frequency location is defined when resource pool is set, and the number of symbols may be set through additional information. Alternatively, an area to be used as the actual PSFCH among the defined location areas used for initial setting, that is, among the PSFCH setting available areas, may be additionally set.

Specifically, a PSFCH transmission available region may be activated/deactivated in a resource pool designated in advance through RRC. When it is configured not to perform the HARQ procedure or for a transport block transmitted for broadcast or the like, the use of PSFCH is unnecessary. Accordingly, when the transmission scheme is set to be semi-static within one resource pool, the PSFCH may be configured to exist only in a portion corresponding to a specific time/frequency resource. However, since this situation is highly likely to change over time, only the PSFCH candidate region is initially set, and the PSFCH region to be activated/deactivated through an additional RRC or the like can be indicated. This region may be transmitted in the form of a PSFCH activation region, or may be indirectly transmitted in the form of a transmission region supporting HARQ.

Fourth Embodiment: Delivering information on the existence of a PSFCH region through DCI and SCI regions

The PSFCH region configured and activated by RRC becomes a region that cannot be used for PSSCH transmission by all terminals using the corresponding resource pool. In this case, if the number of pre-set PSFCH regions is small, a case in which a sufficient amount of PSFCH cannot be utilized may occur, and if the pre-set number of PSFCH regions is large, resource waste may occur. Accordingly, a method of excluding only the actually allocated region from transmission resources by transmitting related information on the region in which the actual PSFCH transmission is to be performed to the terminal using the corresponding slot may be considered. Specifically, the following methods can be used.

When the scheduler indicates a transmission resource, information on the RB location and number of symbols in which the PSFCH is located can be delivered. This is based on the PSFCH usage information known by the base station or the scheduling terminal, and when the slot in which the corresponding transmission is performed is indicated to another terminal as a sidelink transmission section, the transmitting terminal is transmitted together with related information on the area in which PSFCH transmission is to be performed. This is a method to configure a transport block excluding the corresponding resource section.

Alternatively, a group common control message may be used. This is a method in which the scheduler groupcasts which PSFCH is allocated/used in a specific sidelink resource pool to all sidelink terminals in every slot or period in which the PSFCH is configured. Through this, the transmitting terminal can configure the transmission area except for the PSFCH area used based on the information acquired through the corresponding group common control message and the scheduling indication message it receives. In this case, the receiving terminal may reconfigure the transmission area to be received based on the SCI and the corresponding group common control message. A DCI/SCI format capable of delivering this may be defined, and the length of the message may depend on the number of PSFCHs inside the resource pool.

Further, the region indicated by the corresponding format may be the same as the slot in which the corresponding DCI is transmitted, or the transmitting end may have a difference as much as DCI-SCI gap + alpha in order to utilize the corresponding information. Here, the DCI-SCI gap refers to the slot distance between the control channel through which the DCI message or the SCI message transmitting the scheduling instruction message is transmitted and the PSCCH through which the transmitting terminal transmits the SCI. It can be set in common. Alpha may be a value determined by the specification and may not be generally required.

Since the corresponding group common control message is a control message transmitted in a semi-persistant manner, it may be transmitted through a separately defined core set (CORESET) in order to lower the blind decoding (BD) probability of terminals.

The above-described first to fourth embodiments and respective sub-methods may be applied independently of each other or may be applied in combination with each other, unless otherwise limited.

Accordingly, PSFCH transmission resources can be effectively managed, and PSFCH transmission resources can be effectively managed without deteriorating sidelink transmission performance of other users through PSFCH transmission.

Hereinafter, configurations of a terminal and a base station capable of performing some or all of the embodiments described with reference to FIGS. 1 to 17 will be described with reference to the drawings.

18 is a diagram showing a configuration of a terminal 1800 according to another embodiment.

Referring to FIG. 18, a terminal 1800 according to another embodiment includes a control unit 1810, a transmission unit 1820, and a reception unit 1830.

The control unit 1810 controls the overall operation of the terminal 1800 according to the method of transmitting HARQ feedback information for sidelink transmission by the terminal required to perform the above-described present invention. The transmitter 1820 transmits uplink control information, data, and messages to a base station through a corresponding channel, and transmits sidelink control information, data, and messages to other terminals through a corresponding channel. The receiving unit 1830 receives downlink control information, data, and messages from the base station through a corresponding channel, and receives sidelink control information, data, and messages from other terminals through the corresponding channel.

The receiver 1830 may receive configuration information on a resource pool for sidelink transmission. The base station may configure a resource pool on radio resources for sidelink transmission and reception between the terminal and other terminals. Here, the resource pool may be a radio resource configured to be used to transmit/receive PSCCH, PSSCH, etc. between the terminal 1800 and other terminals. The terminal 1800 may receive configuration information on the resource pool from the base station through higher layer signaling.

The controller 1810 may generate a signal for transmitting HARQ feedback information for a PSSCH received from another terminal based on a sequence associated with the resource pool. When the PSSCH is received, the control unit 1810 may be configured to transmit HARQ ACK/NACK feedback information corresponding to the received PSSCH to the terminal that transmitted the PSSCH. Accordingly, the control unit 1810 may configure HARQ ACK/NACK feedback information corresponding to the received PSSCH. According to an example, whether to transmit HARQ feedback information may be indicated by SCI including scheduling information for PSSCH. That is, information indicating HARQ feedback information may be transmitted together in the SCI including resource allocation information for PSSCH transmission.

The control unit 1810 may use a sequence associated with a resource pool for sidelink transmission in order to generate a signal for transmitting the configured HARQ feedback information. According to an example, the configuration information on the resource pool received from the base station may include information on a sequence preconfigured for the corresponding resource pool.

When generating a signal for transmitting HARQ feedback information using a sequence associated with a resource pool, the control unit 1810 may apply a predetermined cyclic shift value to minimize interference with each other. For example, when many signals are overlapped, the noise of the sum of the interference signals becomes large enough to be negligible, so in an environment where interference control is important, a different cyclic shift may be applied for each terminal for a specific sequence so that the correlation characteristic becomes 0. .

All UEs sharing the PSFCH resource have a common symbol length and sequence number value depending on a preset value. In this case, according to an example, a possible cyclic shift value may depend on the length of the sequence. For example, if the length of the sequence is 12, 12 types of cyclic shift values may be used. In addition, according to an example, when HARQ feedback information configured in each terminal is ACK/NACK, allocation according to each may be possible.

That is, according to an example, the cyclic shift value may be applied to the sequence based on at least one of an ID of a terminal, an ID of another terminal, or a value of HARQ feedback information for a PSSCH. For example, the ID of the receiving terminal receiving the PSSCH may be indicated by a higher layer. The ID of another terminal that has transmitted the PSSCH may be provided by SCI including scheduling information for the PSSCH. That is, a separate cyclic shift may be determined based on a case in which HARQ feedback information for PSSCH reception at each UE is ACK and NACK in addition to ID information of UEs transmitting and receiving PSSCH.

The transmitter 1820 may transmit a signal generated through a physical sidelink feedback channel (PSFCH) in a resource pool. According to an example, a PSFCH resource that can be used when transmitting a PSFCH may be indicated within a resource pool for sidelink transmission configured between a terminal and another terminal. The receiver 1830 may receive configuration information on a frequency resource through which a PSFCH can be transmitted within a resource pool.

According to an example, the frequency resource for PSFCH transmission may be configured as a set of PRBs in a resource pool for sidelink transmission. In this case, configuration information on frequency resources for PSFCH transmission may be received by higher layer signaling.

In general, since the PSFCH is required to correspond to each of one transport block, it is not necessary to set a transmission zone for every RB. That is, at the time of initial transmission, the PSFCH is set to be transmitted only at a location corresponding to one PSCCH transmission region, and a terminal performing transmission through the remaining slots in which the corresponding region exists can perform transmission with the corresponding region empty. have. In this case, the symbol length of the PSFCH is set through RRC information other than the initial resource pool resource setting, and resource allocation of the resource pool may be determined through this.

Based on the number of subchannels for the resource pool and the number of PSSCH slots associated with the PSFCH slot, the control unit 1810 is a PSFCH used to transmit HARQ feedback information among a set of PRBs based on configuration information for frequency resources in the resource pool. One or more PRBs for can be determined. In addition, the control unit 1810 may determine the number of PSFCH resources used to transmit HARQ feedback information.

In addition, transmission of the HARQ feedback information may be performed based on timing gap information between reception of the PSSCH and transmission of HARQ feedback information for reception of the PSSCH, received through higher layer signaling. In this case, according to an example, PSFCH transmission may be performed in a first slot including a PSFCH resource in a resource pool after the last slot of PSSCH reception.

Accordingly, the transmitter 1820 may transmit a signal generated for HARQ feedback information on the received PSSCH through the PSFCH resource determined from the resource pool.

Accordingly, it is possible to provide a specific method and apparatus capable of generating a signal transmitted through PSFCH in order to transmit HARQ feedback information for sidelink transmission in NR.

19 is a diagram showing a configuration of a base station 1900 according to another embodiment.

Referring to FIG. 19, a base station 1900 according to another embodiment includes a control unit 1910, a transmission unit 1920, and a reception unit 1930.

The control unit 1910 controls the overall operation of the base station 1900 according to a method in which the base station required to perform the above-described present invention controls transmission of HARQ feedback information for sidelink transmission of the terminal. The transmitting unit 1920 and the receiving unit 1930 are used to transmit and receive signals, messages, and data necessary for carrying out the above-described present invention with the terminal.

The transmitter 1920 may transmit configuration information on a resource pool for sidelink transmission. The controller 1910 may configure a resource pool on radio resources for sidelink transmission/reception between a terminal and another terminal. Here, the resource pool may be a radio resource configured to be used to transmit/receive a PSCCH, a PSSCH, or the like between a terminal and another terminal. The transmitter 1920 may transmit configuration information on the resource pool to the terminal through higher layer signaling.

The transmitter 1920 may transmit configuration information on the PSFCH resource within the resource pool. According to an example, a PSFCH resource that can be used when transmitting a PSFCH may be indicated within a resource pool for sidelink transmission configured between a terminal and another terminal. In this case, in addition to the PSCCH region and the PSSCH region, a PSFCH region may exist in the resource pool. In particular, the transmitter 1920 may transmit configuration information on a frequency resource through which a PSFCH can be transmitted within a resource pool.

According to an example, the frequency resource for PSFCH transmission may be configured as a set of PRBs in a resource pool for sidelink transmission. In this case, configuration information on frequency resources for PSFCH transmission may be received by higher layer signaling.

In general, since the PSFCH is required to correspond to each of one transport block, it is not necessary to set a transmission zone for every RB. That is, at the time of initial transmission, the PSFCH is set to be transmitted only at a location corresponding to one PSCCH transmission region, and a terminal performing transmission through the remaining slots in which the corresponding region exists can perform transmission with the corresponding region empty. have. In this case, the symbol length of the PSFCH is set through RRC information other than the initial resource pool resource setting, and resource allocation of the resource pool may be determined through this.

The UE is based on the number of subchannels for the resource pool and the number of PSSCH slots associated with the PSFCH slot, one of the PSFCH used to transmit HARQ feedback information among the set of PRBs based on the configuration information for the frequency resource in the resource pool. The above PRB can be determined. In addition, the terminal may determine the number of PSFCH resources used to transmit HARQ feedback information.

When a PSSCH is received, the UE may be configured to transmit HARQ ACK/NACK feedback information corresponding to the received PSSCH to the UE transmitting the PSSCH. Accordingly, the UE can configure HARQ ACK/NACK feedback information corresponding to the received PSSCH. According to an example, whether to transmit HARQ feedback information may be indicated by SCI including scheduling information for PSSCH. That is, information indicating HARQ feedback information may be transmitted together in the SCI including resource allocation information for PSSCH transmission.

The terminal may use a sequence associated with a resource pool for sidelink transmission in order to generate a signal for transmitting the configured HARQ feedback information. According to an example, the configuration information on the resource pool received from the base station 1900 may include information on a sequence preconfigured for the corresponding resource pool.

When generating a signal for transmitting HARQ feedback information using a sequence associated with a resource pool, the UE may apply a predetermined cyclic shift value to minimize interference with each other. Signals generated through this may be orthogonal to each other and may be generated to minimize interference.

For example, when many signals are overlapped, the noise of the sum of the interference signals becomes large enough to be negligible, so in an environment where interference control is important, a different cyclic shift may be applied for each terminal for a specific sequence so that the correlation characteristic becomes 0. .

All UEs sharing the PSFCH resource have a common symbol length and sequence number value depending on a preset value. According to an example, when HARQ feedback information configured in each terminal is ACK/NACK, allocation according to each may be possible.

That is, according to an example, the cyclic shift value may be applied to the sequence based on at least one of an ID of a terminal, an ID of another terminal, or a value of HARQ feedback information for a PSSCH. For example, the ID of the receiving terminal receiving the PSSCH may be indicated by a higher layer. The ID of another terminal that has transmitted the PSSCH may be provided by SCI including scheduling information for the PSSCH. That is, a separate cyclic shift may be determined based on a case in which HARQ feedback information for PSSCH reception at each UE is ACK and NACK in addition to ID information of UEs transmitting and receiving PSSCH.

Accordingly, the UE may transmit a signal generated for HARQ feedback information for the received PSSCH through the PSFCH resource determined from the resource pool. In this case, according to an example, transmission of HARQ feedback information may be performed based on timing gap information between reception of PSSCH and transmission of HARQ feedback information for reception of PSSCH, received through higher layer signaling. For example, PSFCH transmission may be performed in a first slot including a PSFCH resource in a resource pool after the last slot of PSSCH reception.

Accordingly, it is possible to provide a specific method and apparatus capable of generating a signal transmitted through PSFCH in order to transmit HARQ feedback information for sidelink transmission in 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 a single 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 terminal to transmit HARQ feedback information for sidelink transmission,
Receiving configuration information on a resource pool for sidelink transmission;
Generating a signal for transmitting HARQ feedback information for a physical sidelink data channel (PSSCH) received from another terminal based on a sequence associated with the resource pool; And
And transmitting the generated signal through a physical sidelink feedback channel (PSFCH) in the resource pool. The method of claim 1,
A signal for transmitting the HARQ feedback information,
A method generated by applying a cyclic shift value to a sequence associated with the resource pool. The method of claim 2,
The cyclic shift value is,
Method applied to the sequence based on at least one of the ID of the terminal, the ID of the other terminal, or a value of HARQ feedback information for the PSSCH. The method of claim 3,
The ID of the other terminal is,
A method provided by sidelink control information (SCI) including scheduling information for the PSSCH. In a method for a base station to control transmission of HARQ feedback information for sidelink transmission of a terminal,
Transmitting configuration information on a resource pool for sidelink transmission; And
Including the step of transmitting configuration information for a sidelink feedback channel (Physical Sidelink Feedback Channel; PSFCH) resources in the resource pool,
The terminal generates a signal for transmitting HARQ feedback information for a sidelink data channel (Physical Sidelink Shared Channel (PSSCH)) received from another terminal based on a sequence associated with the resource pool, and the PSFCH Method of transmitting the generated signal through. The method of claim 5,
A signal for transmitting the HARQ feedback information,
A method generated by applying a cyclic shift value to a sequence associated with the resource pool. The method of claim 6,
The cyclic shift value is,
Method applied to the sequence based on at least one of the ID of the terminal, the ID of the other terminal, or a value of HARQ feedback information for the PSSCH. The method of claim 7,
The ID of the other terminal is,
A method provided by sidelink control information (SCI) including scheduling information for the PSSCH. In the terminal for transmitting HARQ feedback information for sidelink transmission,
A receiving unit for receiving setting information on a resource pool for sidelink transmission;
A control unit for generating a signal for transmitting HARQ feedback information for a sidelink data channel (Physical Sidelink Shared Channel (PSSCH)) received from another terminal based on a sequence associated with the resource pool; And
Terminal comprising a transmitter for transmitting the generated signal through a sidelink feedback channel (Physical Sidelink Feedback Channel; PSFCH) in the resource pool. The method of claim 9,
A signal for transmitting the HARQ feedback information,
A terminal generated by applying a cyclic shift value to a sequence associated with the resource pool. The method of claim 10,
The cyclic shift value is,
A UE applied to the sequence based on at least one of the ID of the UE, the ID of the other UE, or a value of HARQ feedback information for the PSSCH. The method of claim 11,
The ID of the other terminal is,
Terminal provided by sidelink control information (SCI) including scheduling information for the PSSCH. In the base station for controlling transmission of HARQ feedback information for sidelink transmission of the terminal,
A transmitter for transmitting configuration information for a resource pool for sidelink transmission, and for transmitting configuration information for a physical sidelink feedback channel (PSFCH) resource within the resource pool,
The terminal generates a signal for transmitting HARQ feedback information for a sidelink data channel (Physical Sidelink Shared Channel (PSSCH)) received from another terminal based on a sequence associated with the resource pool, and the PSFCH The base station for transmitting the generated signal through. The method of claim 13,
A signal for transmitting the HARQ feedback information,
A base station generated by applying a cyclic shift value to a sequence associated with the resource pool. The method of claim 14,
The cyclic shift value is,
The base station applied to the sequence based on at least one of the ID of the terminal, the ID of the other terminal, or a value of HARQ feedback information for the PSSCH. The method of claim 15,
The ID of the other terminal is,
A base station provided by sidelink control information (SCI) including scheduling information for the PSSCH.

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