KR102467308B1 - 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, and an embodiment is a method for transmitting HARQ feedback information for sidelink transmission by a UE, a resource pool for sidelink transmission. Receiving configuration information for ), based on a sequence associated with a resource pool, a signal for transmitting HARQ feedback information for a physical sidelink shared channel (PSSCH) received from another terminal It provides a method including generating and transmitting the generated signal through a sidelink feedback channel (Physical Sidelink Feedback Channel; PSFCH) in a resource pool.

Description

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 (ie, 5G radio access technology), and based on this, RAN WG1 each for NR (New Radio) Designs for 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 specified usage scenario as well as an improved data rate in preparation for LTE.

eMBB (enhancement Mobile BroadBand), mMTC (massive machine type communication), and URLLC (Ultra Reliable and Low Latency Communications) have been defined as representative usage scenarios of NR, and a frame structure that is flexible compared to LTE to satisfy the needs of each usage scenario design is required.

Since each usage scenario has different requirements for data rates, latency, reliability, coverage, etc. As a method for efficiently satisfying the needs of each usage scenario, based on different numerologies (eg, subcarrier spacing, subframe, TTI (Transmission Time Interval), etc.) There is a need for a method of efficiently multiplexing radio resource units of .

As part of this aspect, a sidelink, which is a radio link between terminals for providing V2X service in NR, that is, a design for generating a signal for transmitting HARQ ACK / NACK feedback information for NR sidelink transmission is required will do

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

In one aspect, the present embodiments are a method for a terminal to transmit HARQ feedback information for sidelink transmission, including receiving configuration information for a resource pool for sidelink transmission, a sequence associated with the resource pool Based on the (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 Channel; PSFCH) can provide a method including the step of transmitting the generated signal.

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

In another aspect, the present embodiments, in a terminal transmitting HARQ feedback information for sidelink transmission, a receiving unit for receiving configuration information on a resource pool for sidelink transmission, a sequence associated with the resource pool ( sequence), a control unit for generating a signal for transmitting HARQ feedback information on a sidelink data channel (Physical Sidelink Shared Channel; PSSCH) received from another terminal and a sidelink feedback channel in a resource pool (Physical Sidelink Feedback Channel) It is possible to provide a terminal including a transmitter for transmitting a signal generated through a PSFCH).

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

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

1 is a diagram schematically illustrating the structure of an NR wireless communication system to which this 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 for explaining a resource grid supported by a radio access technology to which this embodiment can be applied.
4 is a diagram for explaining a bandwidth part supported by a radio access technology to which this embodiment can be applied.
5 is a diagram exemplarily illustrating a synchronization signal block in a radio access technology to which this embodiment can be applied.
6 is a diagram for explaining a random access procedure in a radio access technology to which this embodiment can be applied.
7 is a diagram for explaining CORESET.
8 is a diagram for explaining various scenarios for V2X communication.
9 illustrates an example of UE 1 (UE1) and UE 2 (UE2) performing sidelink communication and a sidelink resource pool they use.
10 is a diagram for explaining a method of bundling and transmitting HARQ feedback information in V2X.
11 illustrates the type of V2X transmission resource pool.
12 is a diagram illustrating an example of symbol level alignment among different SCSs in different SCSs to which this embodiment can be applied.
13 is a diagram illustrating a conceptual example of a bandwidth part to which this embodiment can be applied.
14 is a diagram illustrating a procedure for transmitting HARQ feedback information for sidelink transmission by a terminal 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 configured for each PSCCH configured 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 the configuration of a base station according to another embodiment.

DETAILED DESCRIPTION Some embodiments of the present disclosure are described in detail below with reference to exemplary drawings. In adding reference numerals to components of each drawing, the same components may have the same numerals as much as possible even if they are displayed on different drawings. In addition, in describing the present embodiments, if 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 "comprises", "has", "consists of", etc. mentioned in this specification is used, other parts may be added unless "only" is used. In the case where a component is expressed in the singular, it may include the case of including the plural unless otherwise explicitly stated.

Also, terms such as first, second, A, B, (a), and (b) may be used in describing the components of the present disclosure. These terms are only used to distinguish the component from other components, and the nature, sequence, order, or number of the corresponding component is not limited by the term.

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

In the description of the temporal flow relationship related to components, operation methods, production methods, etc., for example, "after", "continued to", "after", "before", etc. Alternatively, when a flow sequence relationship is described, it may also include non-continuous cases unless “immediately” or “directly” is used.

On the other hand, when a numerical value or corresponding information (eg, level, etc.) for a component is mentioned, even if there is no separate explicit description, the numerical value or its corresponding information is not indicated by various factors (eg, process factors, internal or external shocks, noise, etc.) may be interpreted as including an error range that may occur.

A 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 present embodiments disclosed below may be applied to wireless communication systems 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), and singlecarrier frequency division multiple access (SC-FDMA). Alternatively, it may be applied to various radio access technologies such as non-orthogonal multiple access (NOMA). In addition, wireless access technology may mean not only a specific access technology, but also a communication technology for each generation established by various communication consultative organizations such as 3GPP, 3GPP2, WiFi, Bluetooth, IEEE, and ITU. For example, CDMA may be implemented as 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 datarates for GSM evolution (EDGE). OFDMA may be implemented with a wireless technology such as institute of electrical and electronic engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, evolved UTRA (E-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 the universal mobile telecommunications system (UMTS). 3rd generation partnership project (3GPP) long term evolution (LTE) is a part of evolved UMTS (E-UMTS) that uses evolved-UMTSterrestrial radio access (E-UTRA). Adopt FDMA. As such, the present embodiments may be applied to currently disclosed or commercialized radio access technologies, and may also be applied to radio access technologies currently under development or to be developed in the future.

Meanwhile, a terminal in the present specification is a comprehensive concept meaning a device including a wireless communication module that communicates with a base station in a wireless communication system, and in WCDMA, LTE, NR, HSPA, and IMT-2020 (5G or New Radio) It should be interpreted as a concept that includes not only User Equipment (UE), but also Mobile Station (MS), User Terminal (UT), Subscriber Station (SS), and wireless device in GSM. In addition, the terminal may be a user portable device such as a smart phone depending on the type of use, or may mean a vehicle or a device including a wireless communication module in the vehicle in the V2X communication system. 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 to perform machine type communication.

A base station or cell in this specification refers to an end that communicates with a terminal in terms of a network, and includes Node-B (Node-B), eNB (evolved Node-B), gNB (gNode-B), LPN (Low Power Node), Sector, site, various types of antennas, base transceiver system (BTS), access point, point (e.g. transmission point, reception point, transmission/reception point), relay node ), mega cell, macro cell, micro cell, pico cell, femto cell, remote radio head (RRH), radio unit (RU), and small cell. Also, a cell may mean including a bandwidth part (BWP) in the frequency domain. For example, the serving cell may mean the activation BWP of the terminal.

Since there is a base station controlling one or more cells in the various cells listed above, the base station can be interpreted in two meanings. 1) In relation to the radio area, it may be a device itself that provides a mega cell, macro cell, micro cell, pico cell, femto cell, or small cell, or 2) it may indicate the radio area itself. In 1), all devices providing a predetermined radio area are controlled by the same entity or all devices interacting to form a radio area cooperatively are directed to the base station. Points, transmission/reception points, transmission points, reception points, etc., according to the configuration method of the radio area, become an example of a base station. In 2), the radio area itself in which signals are received or transmitted may be indicated to the base station from the viewpoint of the user terminal or the neighboring base station.

In this 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 (transmission point or transmission/reception point), and the transmission/reception point itself. can

Uplink (UL, or uplink) means a method of transmitting and receiving data from a terminal to a base station, and downlink (DL, or downlink) means a method of transmitting and receiving data from a base station to a terminal do. Downlink may mean communication or a communication path from multiple transmission/reception points to a terminal, and uplink may mean 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 a multi-transmission/reception point, and the receiver may be a part of a terminal. Also, in uplink, a transmitter may be a part of a terminal, and a receiver may be a part of a multi-transmission/reception point.

In uplink and downlink, control information is transmitted and received through control channels such as a physical downlink control channel (PDCCH) and a physical uplink control channel (PUCCH), and a physical downlink shared channel (PDSCH) and a physical uplink shared channel (PUSCH). It configures the same data channel to transmit and receive data. Hereinafter, a situation in which signals are transmitted and received through channels such as PUCCH, PUSCH, PDCCH, and PDSCH may be expressed as 'transmitting and receiving PUCCH, PUSCH, PDCCH, and PDSCH'.

For clarity of explanation, 3GPP LTE/LTE-A/NR (New RAT) communication system is mainly described in the following technical idea, but the technical features are 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 develops a new NR communication technology separate from LTE-A pro and 4G communication technology, which has improved LTE-Advanced technology to meet the requirements of ITU-R as a 5G communication technology. Both LTE-A pro and NR refer to 5G communication technology. Hereinafter, 5G communication technology will be described focusing on NR when a specific communication technology is not specified.

Operating scenarios in NR defined various operating scenarios by adding consideration to satellites, automobiles, and new verticals in the existing 4G LTE scenarios. It is deployed in the range to support mMTC (Massive Machine Communication) scenarios that require low data rates and asynchronous access, and URLLC (Ultra Reliability and Low Latency) scenarios that require high responsiveness and reliability and can support high-speed mobility. .

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

<NR System General>

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

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

<NR wave form, numerology 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 multiple input multiple output (MIMO) and has the advantage of using a low-complexity receiver with high frequency efficiency.

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

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

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 numerology of NR can be classified into five types according to the subcarrier spacing. This is different from the fact that the subcarrier interval of LTE, which is one of 4G communication technologies, 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. Meanwhile, a frame structure in NR is defined as a frame having a length of 10 ms composed of 10 subframes having the same length of 1 ms. One frame may be divided into half frames of 5 ms, and each half frame includes 5 subframes. In the case of a 15 kHz subcarrier spacing, one subframe consists of one 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, a slot is fixedly composed of 14 OFDM symbols in the case of a normal CP, but the length of the slot in the time domain may vary according to the subcarrier interval. For example, in the case of a numerology having a 15 kHz subcarrier interval, a slot is 1 ms long and has the same length as a subframe. In contrast, in the case of numerology having a 30 kHz subcarrier interval, a slot is composed of 14 OFDM symbols, but two slots may be included in one subframe with a length of 0.5 ms. That is, subframes and frames are defined with a fixed time length, and slots are defined by the number of symbols, and the time length may vary according to subcarrier intervals.

Meanwhile, NR defines a basic unit of scheduling as a slot, and introduces a mini-slot (or sub-slot or non-slot based schedule) to reduce transmission delay in a radio section. When a wide subcarrier interval is used, the length of one slot is shortened in inverse proportion to a transmission delay in a radio section. Mini-slots (or sub-slots) are for efficient support of URLLC scenarios and can be scheduled in units of 2, 4, or 7 symbols.

Also, unlike LTE, NR defines uplink and downlink resource allocation at the symbol level within one slot. In order to reduce HARQ delay, a slot structure capable of directly transmitting HARQ ACK/NACK 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 of a slot are set to uplink, and a slot structure in which downlink symbols and uplink symbols are combined are supported. NR also supports that data transmissions are distributed and scheduled over one or more slots. Therefore, the base station can inform the terminal whether the slot is a downlink slot, an uplink slot, or a flexible slot using a slot format indicator (SFI). The base station may indicate the slot format by indicating the index of the table configured through UE-specific RRC signaling using SFI, dynamically indicating through DCI (Downlink Control Information), or static or static through RRC. It can also be given quasi-statically.

<NR physical resources>

Regarding physical resources in NR, antenna ports, resource grids, resource elements, resource blocks, bandwidth parts, etc. are considered do.

An antenna port is defined such that the channel on which a symbol on an antenna port is carried can be inferred from the channel on which other symbols on the same antenna port are carried. If the large-scale properties of the channel on which symbols on one antenna port are carried can be inferred from the channel on which the symbols on the other antenna port are carried, the two antenna ports are quasi co-located or QC/QCL. quasi co-location). Here, the wide range characteristics include one or more of delay spread, Doppler spread, frequency shift, average received power, and received timing.

3 is a diagram for explaining a resource grid supported by a radio access technology to which this embodiment can be applied.

Referring to FIG. 3 , since NR supports a plurality of numerologies in the same carrier, a resource grid may exist according to each numerology. Also, resource grids may exist according to antenna ports, subcarrier intervals, and transmission directions.

A resource block consists of 12 subcarriers and is defined only in the frequency domain. Also, a resource element is composed 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, in NR, “Point A”, which serves as a common reference point for the resource block grid, and common resource blocks and virtual resource blocks are defined.

4 is a diagram for explaining a bandwidth part supported by a radio access technology to which this 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 NR, as shown in FIG. 4, a bandwidth part (BWP) can be designated and used by a UE within a carrier bandwidth. In addition, the bandwidth part is associated with one numerology, is composed of a subset of consecutive common resource blocks, and can be dynamically activated according to time. Up to four bandwidth parts each of uplink and downlink are configured in the terminal, and data is transmitted and received using the active bandwidth part at a given time.

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

<NR initial connection>

In NR, a UE accesses a base station and performs a cell search and random access procedure to perform communication.

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

5 is a diagram exemplarily illustrating a synchronization signal block in a radio access technology to which this embodiment can be applied.

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

The UE receives the SSB by monitoring the SSB in the time and frequency domains.

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

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

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

The UE may acquire the MIB through the PBCH of the SSB. MIB (Master Information Block) includes minimum information for the terminal to receive the remaining system information (RMSI, Remaining Minimum System Information) broadcast by the network. In addition, the PBCH includes information about the position of the first DM-RS symbol in the time domain, information for monitoring SIB1 by the UE (eg, SIB1 numerology 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 location of the absolute SSB within the carrier is transmitted through SIB1), and the like. Here, the SIB1 numerology information is equally applied to some messages used in the random access procedure for accessing the base station after the UE completes the cell search procedure. For example, the numerical 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 (eg, 160 ms) broadcast in a cell. SIB1 includes information necessary for the terminal to perform an initial random access procedure, and is periodically transmitted through the PDSCH. In order for the terminal to receive SIB1, it needs to receive numerology 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 the SI-RNTI in CORESET, and acquires SIB1 on PDSCH according to the scheduling information. The remaining SIBs except for SIB1 may be transmitted periodically 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 this embodiment can be applied.

Referring to FIG. 6, when cell search is completed, the terminal transmits a random access preamble for random access to the base station. The random access preamble is transmitted through PRACH. Specifically, the random access preamble is transmitted to the base station through a PRACH composed of contiguous radio resources in a periodically repeated specific slot. In general, when a UE initially accesses a cell, a contention-based random access procedure is performed, and when random access is performed for beam failure recovery (BFR), a non-contention-based 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), UL Grant (uplink radio resource), temporary C-RNTI (Temporary Cell-Radio Network Temporary Identifier), and 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 indicate to 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. The 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 information included in the random access response and performs scheduled transmission to the base station. For example, the UE applies TAC and stores the temporary C-RNTI. In addition, data stored in the buffer of the terminal or newly generated data is transmitted to the base station using the UL grant. In this case, information capable of identifying the terminal must be included.

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

<NR CORESET>

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

In this way, NR introduced the concept of CORESET to secure the flexibility of the system. A control resource set (CORESET) means a time-frequency resource for a downlink control signal. The UE may decode the control channel candidate using one or more search spaces in the CORESET time-frequency resource. A Quasi CoLocation (QCL) assumption for each CORESET is set, which is used for the purpose of notifying 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 the conventional QCL.

7 is a diagram for explaining CORESET.

Referring to FIG. 7 , a CORESET may exist in various forms within a carrier bandwidth within one slot, and a CORESET may consist of up to three 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 to allow additional configuration and system information to be received from the network. After establishing a 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, a radio channel and radio protocol were designed for direct communication (ie, side link) between devices to provide direct communication between devices and V2X (especially V2V) services.

Regarding the sidelink, PSSS / SSSS, which is a synchronization signal for synchronization between a wireless sidelink transmitter and a receiver, and PSBCH (Physical Sidelink Broadcasting Channel) for transmitting and receiving a related sidelink MIB (Master Information Block) have been defined, and also discovery information A design was made for a Physical Sidelink Discovery channel (PSCH) 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, in order to allocate radio resources for the sidelink, a technology has been developed that is divided into mode 1 in which a base station allocates radio resources and mode 2 in which a terminal selects and allocates radio resources from a radio resource pool. In addition, additional technological evolution was required in the LTE system 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 the recent Rel-15, 25 more advanced service scenarios such as platooning, advanced driving, and long-distance vehicle sensors were derived and six performance requirements were determined.

In order to satisfy these performance requirements, technology development has been conducted to improve the performance of sidelink technology developed based on conventional D2D communication to meet the requirements of V2X. In particular, in order to apply to C-V2X (Cellular-V2X), a technology that improves the physical layer design of the sidelink to be suitable for a high-speed environment, a resource allocation technology, and a 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. Regardless of Rel-14 and 15 requirements, the same terms are used. However, for convenience of understanding, if necessary, the sidelink for D2D communication in Rel-12/13 will be described focusing on the difference between sidelinks that satisfy V2X scenario requirements. Therefore, the terminology related to sidelinks described below only describes D2D communication / V2X communication / C-V2X communication for the convenience of comparison and understanding, and is 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 can be set in various ways such as a user terminal) may be located within the coverage of a base station (eNB or gNB or ng-eNB) or outside the coverage of the base station. For example, communication may be performed between terminals within the coverage of the base station (UE N-1, UE G-1, and UE X), or between a terminal within the coverage of the base station and a terminal outside the coverage (ex, UE N-1, UE N-1). 2) may perform communication. Alternatively, communication may be performed between terminals outside the coverage of the base station (eg, UE G-1 and UE G-2).

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

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

9 illustrates an example of UE 1 (UE1) and UE 2 (UE2) performing sidelink communication and a sidelink resource pool they use.

Referring to FIG. 9, the base station is indicated as eNB, but as described above, it may be gNB or ng-eNB. In addition, although a mobile phone is exemplarily shown as a terminal, it may be applied to various vehicles, infrastructure devices, and the like.

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

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

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

Meanwhile, resource pools may be subdivided into several types. First, it can be classified according to the contents of sidelink signals transmitted in each resource pool. For example, the contents of sidelink signals can be differentiated, and separate resource pools can be configured for each. As the contents 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 MCS (modulation and coding scheme), MIMO transmission method, and TA (timing advance) required for demodulation of other data channels and the location of resources used by the transmitting terminal for transmission of the following sidelink data channel. It may be a signal containing This signal can also be multiplexed and transmitted together with sidelink data on the same resource unit. In this case, the SA resource pool may mean a resource pool in which SA is multiplexed with sidelink data and transmitted.

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

Meanwhile, when SA is multiplexed and transmitted along with sidelink data on the same resource unit, only sidelink data channels excluding SA information may be transmitted in a resource pool for sidelink data channels. In other words, resource elements 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 in which a transmitting terminal transmits information such as its own ID so that a neighboring terminal can discover itself. Even when the contents of sidelink signals are the same, different resource pools may be used according to transmission/reception properties of sidelink signals.

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

<sync signal>

As described above, in the case of a V2X communication terminal, it is likely to be located outside the coverage of the base station. Even in this case, communication using the side link must be performed. To this end, the problem of acquiring synchronization by a terminal located outside the base station coverage is important.

Hereinafter, based on the above description, a method for synchronizing time and frequency in sidelink communication, particularly in communication between vehicles, between vehicles and other terminals, and between vehicles and an infrastructure network, 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 priority information. For example, in determining its own transmission synchronization, a UE selects a synchronization signal directly transmitted by a base station with the highest priority, and if it is located outside the coverage of the base station, it preferentially synchronizes with SLSS transmitted by a UE within the coverage of the base station. it will fit

On the other hand, since a wireless terminal installed in a vehicle or a terminal mounted in a vehicle has relatively less problems with battery consumption and can use satellite signals such as GPS for navigation purposes, time or frequency synchronization between terminals is set using satellite signals. can be used to do Here, the satellite signals may correspond to GNSS signals such as Global Positioning System (GLONAS), GALILEO, and BEIDOU in addition to the exemplified Global Positioning System (GPS).

Meanwhile, sidelink synchronization signals may include a primary sidelink synchronization signal (PSSS) and a secondary sidelink synchronization signal (SSSS). The PSSS may have a Zadoff-chu sequence of a predetermined length or a similar/modified/repeated structure to the PSS. Also, unlike the DL PSS, other Zadoff Chu root indices (eg, 26 and 37) may be used. SSSS may have a similar/modified/repeated structure to M-sequence or SSS. If the terminals synchronize 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 the UL subcarrier mapping scheme. PSSCH (Physical Sidelink synchronization channel) is the basic system information that the terminal needs to know first before transmitting and receiving the sidelink signal (eg, information related to SLSS, duplex mode (Duplex Mode, DM), TDD UL / DL configuration, resource pool related information, type of application related to SLSS, subframe offset, broadcast information, etc.) may be transmitted. PSSCH may be transmitted on the same subframe as SLSS or on a subsequent subframe. DM-RS can be used for demodulation of PSSCH.

SRN may be a node transmitting 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 undergoing predetermined 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 coverage, the UE may become an SRN.

In addition, SLSS may be relayed for sidelink communication with out-of-coverage terminals as needed and may be relayed through multiple hops. In the following description, relaying a synchronization signal is a concept that includes not only relaying a synchronization signal of a base station directly, but also transmitting a sidelink synchronization signal in a separate format according to a synchronization signal reception time. In this way, by relaying the sidelink synchronization signal, the in-coverage terminal and the out-of-coverage terminal can perform direct communication.

<NR Sidelink>

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

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

In NR V2X, it is decided to support unicast and group cast as well as broadcast used in LTE V2X. At this time, it was decided to use the target group ID for group cast and unicast, but whether to use the source ID will be discussed later.

In addition, as it is decided to support HARQ for QOS, it is also decided to include a HARQ process ID in the control information. In LTE HARQ, PUCCH for HARQ was transmitted 4 subframes after downlink transmission, but in NR HARQ, the feedback timing is, for example, in DCI format 1_0 or 1_1 PUCCH resource indicator (PUCCH resource indicator) or HARQ feedback for PDSCH PUCCH resources and feedback timing may 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 was not transmitted to reduce system overhead, and the transmitting terminal was allowed to retransmit data once according to selection for data transmission safety. However, 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 it may be transmitted through a separate channel or another channel, and the bundled HARQ information may consist of 3 bits or less.

Meanwhile, in FR1 for the frequency domain below 3 GHz, it was decided to discuss 15 kHz, 30 kHz, 60 kHz, and 120 kHz as SCS (Subcarrier spacing) candidates. In addition, 30 kHz, 60 kHz, 120 kHz, and 240 kHz were discussed as candidates for subcarrier spacing (SCS) for FR2 in the frequency region exceeding 3 GHz. In NR V2X, mini-slots (eg, 2/4/7 symbols) smaller than 14 symbols may be supported as a minimum scheduling unit.

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

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

synchronization mechanism

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

resource allocation

NR V2X sidelink communication can define at least two sidelink resource allocation modes, that is, mode 3 and mode 4. In mode 3, the base station schedules sidelink resource(s) used by the terminal for sidelink transmission. In mode 4, the UE determines the 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 sidelink resources for transmission, assists in selecting sidelink resources for other UE(s), is configured with a configured grant for sidelink transmission, or supports sidelink resources of other UE(s). Transmission can be scheduled.

V2X resource pool (Sensing and selection windows)

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

11 illustrates the type of 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 regular intervals.

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 terminal may randomly select a V2X transmission resource in a selection window without performing (partial) sensing.

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 (/ signaled) so that it is not semi-statically reserved. The base station may configure 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 also exist. The base station may inform that the V2X resource can be selected by one of the (partial) sensing and random selection (either of the partial sensing and the random selection).

In this specification, a frequency, frame, subframe, resource, resource block, region, band, subband, control channel, data channel, synchronization signal, various reference signals, various signals, or various messages related to NR (New Radio) can be interpreted in various meanings used in the past or currently used or in the future.

NR(New Radio)

NR, which has recently been conducted in 3GPP, has been designed to satisfy various QoS requirements required for each segmented and specified service requirement (usage scenario) as well as an improved data rate compared to LTE. In particular, eMBB (enhancement Mobile BroadBand), mMTC (massive Machine Type Communication), and URLLC (Ultra Reliable and Low Latency Communications) have been defined as representative service requirements (usage scenario) of NR. As a method for satisfying , a frame structure design that is flexible compared to LTE/LTE-Advanced is required.

Since each usage scenario has different requirements for data rates, latency, reliability, and coverage, the frequency constituting an arbitrary NR system A radio resource unit based on different numerologies (eg, subcarrier spacing, subframe, TTI, etc.) as a method for efficiently satisfying the needs of each usage scenario through a band It is designed to efficiently multiplexing .

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

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

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

In particular, in the case of transmission and reception of latency-critical data such as URLLC, 1 ms (14 symbols)-based When scheduling is performed in units of slots, it may be difficult to satisfy the latency requirement. For this purpose, a mini-slot composed of a smaller number of OFDM symbols than the corresponding slot is defined, and based on this, a critical (latency critical) data can be defined to be scheduled.

Alternatively, as described above, by multiplexing and supporting numerologies having different SCS values in one NR carrier by TDM and / or FDM method, each numerology A method of scheduling data according to latency requirements 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 case where the SCS is 15 kHz, so when one slot is configured with the same 14 OFDM symbols, the 15 kHz-based The slot length is 1 ms, whereas the slot length based on 60 kHz is reduced to about 0.25 ms.

As such, in NR, discussions are underway on how to satisfy the requirements of URLLC and eMBB by defining different SCS or different TTI lengths.

Wider bandwidth operations

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

However, in the case of NR, the design is made to enable support for NR terminals having different transmission and reception bandwidth capabilities through one wideband NR CC, and accordingly, FIG. 13 and As such, by configuring one or more bandwidth parts (BWP, bandwidth part(s)) composed of subdivided bandwidths for any NR CC, flexible (bandwidth part configuration) and activation through different bandwidth part configuration and activation for each terminal It is required to support a flexible wider bandwidth operation.

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

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

However, in an arbitrary serving cell, a plurality of downlink and/or uplink bandwidth parts are activated and used at the same time according to the capability of the UE and the configuration of the bandwidth part(s). However, in NR rel-15, it is defined to activate and use only one downlink bandwidth part (DL bandwidth part) and one uplink bandwidth part (UL bandwidth part) at any time in any 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 any 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 field of DCI. However, the PUCCH resource set is configured for each UL BWP configured for the corresponding UE, and it is defined that separate PUCCH resource sets are configured 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 and reception method for supporting V2X communication, which is a convergence of D2D, which is terminal-to-device communication, V2V, which is an expanded form of vehicle-to-vehicle communication, and V2I, which is vehicle-base station communication, is used. It is standardized as an additional feature. More specifically, D2D is a service scenario that assumes communication between existing terminals in an equal relationship, and V2V is an extended terminal-to-device communication service scenario that assumes a wireless communication environment between vehicle terminals with characteristics different from those of general pedestrians. In order to successfully utilize radio resources with or without assistance from a base station, various technologies are standardized in terms of initial access and resource allocation.

In NR, studies for V2X-related standardization that meet sidelink support and changed service requirements are in progress, and the following four new service scenarios are largely assumed.

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

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

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

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

On the other hand, in NR V2X, it has been 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 four as follows: Four types of transmission have been agreed upon, and each is expressed as Mode 2-(a) to Mode 2-(d) or Mode 2a to Mode 2d.

Mode-2a: The UE autonomously selects sidelink resource 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: 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, later, mode 2b for transmitting 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. In the case of Mode-2d, Rel. It was agreed not to introduce it into 16 features.

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

1) The base station sets a resource pool for PSCCH transmission to all terminals. The corresponding pool is divided into regions (1x4 = total of 4 RBs) consisting of two subframes and 1 RB bandwidth, and an index consisting of 6 bits is assigned 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 to the same location in the lower half band (8 RBs in total).

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

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

4) Other terminals continue to search the inside of the resource pool for PSCCH transmission, and when a PSCCH transmitted by a desired user is detected, the data region resource location and MCS are detected 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 corresponding 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 similar sensing if it is empty. At this time, the data area resource inside the message follows the resource area set by itself. Then, the terminal encodes the data to be transmitted using the MCS value selected by the terminal, and then maps the data region resource and transmits the data.

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

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

1) The base station sets a resource pool for PSCCH transmission to all terminals. At this time, the PSCCH may be set to be adjacent to the PSSCH indicated by the PSCCH or may be set independently. When set independently, it is similar to LTE Mode 1, but the resource pool is divided into one subframe and two contiguous RB areas (2x2 = total 4 RBs), and an index consisting of k bits is assigned to each area. Here, k varies according to the bandwidth size of the configured resource pool. When the PSCCH and the PSSCH indicated by the PSCCH 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 used as PSCCH transmission candidate areas (2x2 = 4 RBs in total), an index consisting of k bits is allocated. Here, k varies according to the bandwidth of the configured resource pool, that is, the number of subchannels. In the case of Mode 3, SCI is not repeatedly transmitted.

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

3) The terminal transmits the SCI format 1 message through the PSCCH resource indicated by k bits based on the information received. 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) The subsequent procedure is the same as in Mode 1.

Sidelink transmission procedure of LTE Mode 4 Basically, the form of a resource pool is the same as Mode 3, and the transmission method is the same as Mode 2. However, a message capable of reserving a resource by setting a specific time resource and a priority message capable of managing QoS are additionally included in the SCI.

On the other hand, in NR V2X, in the case of NR-based V2X, the need for support for sidelink transmission and reception based on unicast or groupcast as well as the above-mentioned broadcast has been raised. As such, 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 an HARQ application method for the corresponding sidelink radio channel. A HARQ ACK/NACK message for a specific message may be transmitted through a sidelink feedback channel (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 form, it was agreed to define a PSFCH region for every slot and for N greater than 1, every N slot, and it was agreed to support at least one 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 yet been discussed.

In this way, when the PSFCH is allocated to the last symbol(s) of the slot, a terminal using the corresponding slot for data transmission must perform transmission except for the resource region used for the PSFCH. However, with the current procedure, the only UEs that can know that such a PSFCH transmission will be made are the first transmitting UE and the UE that has received the corresponding block, so when another UE tries to use the corresponding resource region, a resource collision problem between the PSSCH region and the PSFCH region may occur. have.

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

Therefore, the present disclosure provides a method for allowing another terminal to know a slot in which a PSFCH region used by a certain terminal exists in an NR sidelink transmission/reception environment. In particular, a method of operating a resource pool in which a 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 is provided.

In addition, the present disclosure provides a method for generating a signal transmitted and received through a PSFCH region in an NR sidelink transmission and reception environment. In particular, a signal generation method based on the Zadoff-Chu sequence is provided for transmitting a feedback message. In addition, a parameter setting method for transmission and reception of the corresponding signal is provided.

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 corresponding PSSCH to a receiving UE through a sidelink. In addition, a receiving terminal (Receiver UE; Rx UE) means a terminal that receives a PSCCH and a corresponding PSSCH from a transmitting terminal through a sidelink.

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

Referring to FIG. 14, the terminal may receive configuration information about 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 for transmitting and receiving a PSCCH, a PSSCH, and 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, mode 2 in which a base station configures a resource pool for sidelinks and manages radio resources through communication between terminals is described, but as long as it is not contrary to the technical idea, the base station configures a sidelink resource pool. Substantially the same can be applied to the case based on mode 1 performing scheduling for transmission.

Referring back to FIG. 14, the terminal generates a signal for transmitting HARQ feedback information for a physical sidelink shared channel (PSSCH) received from another terminal based on a sequence associated with a resource pool. It can (S1410).

When the 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 may 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 an SCI including resource allocation information for PSSCH transmission.

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

When a 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 a cyclic shift in the time domain means applying a linear phase rotation in the frequency domain, and signals generated through this may be orthogonal to each other, so that interference is minimized.

For example, when many signals overlap, since the noise of the sum of interference signals becomes too large to be ignored, in an environment where interference control is important, a different cyclic shift may be applied for each terminal with respect to a specific sequence so that the mutual correlation characteristic becomes 0. .

All terminals sharing the PSFCH resource have a common symbol length and sequence number value depending on preset values. In this case, according to an example, possible cyclic shift values may depend on the length of the sequence. For example, when the length of the sequence is 12, 12 types of cyclic shift values may be used. In addition, according to an example, when the 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 a 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 the PSSCH. For example, the ID of the receiving terminal receiving the PSSCH may be indicated by a higher layer. The ID of another UE that has transmitted the PSSCH may be provided by SCI including scheduling information for the PSSCH. That is, separate cyclic shifts may be determined based on the case where HARQ feedback information for PSSCH reception in each terminal is ACK and NACK, in addition to ID information of terminals transmitting and receiving PSSCH.

Referring back to FIG. 14, the terminal may transmit the generated signal 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 terminal may receive configuration information about a frequency resource through which a PSFCH can be transmitted within a resource pool.

According to an example, a frequency resource for PSFCH transmission may be composed of a set of physical resource blocks (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 PSFCHs are required to correspond to one transport block, transport zones do not need to be configured for every RB. That is, during initial transmission, the PSFCH is set to be transmitted only to a location corresponding to one PSCCH transmission area, and a terminal performing transmission through the remaining slots in which the corresponding area exists can leave the corresponding area empty and transmit. 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 arrangement of the resource pool can 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 UE transmits HARQ feedback information among a set of PRBs based on configuration information for frequency resources in the resource pool. One for PSFCH used to transmit More than one PRB can be determined. In addition, the UE may determine the number of PSFCH resources used to transmit HARQ feedback information.

In addition, 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. In this case, according to an example, transmission of the PSFCH may be performed in the first slot including the PSFCH resource in the resource pool after the last slot of PSSCH reception.

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

According to this, it is possible to provide a specific method and apparatus capable of generating a signal transmitted through the 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 about 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 for transmitting and receiving a PSCCH, a PSSCH, and 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 the 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 terminal may receive configuration information about a frequency resource through which a PSFCH can be transmitted within a resource pool.

According to an example, a frequency resource for PSFCH transmission may be composed of 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 PSFCHs are required to correspond to one transport block, transport zones do not need to be configured for every RB. That is, during initial transmission, the PSFCH is set to be transmitted only to a location corresponding to one PSCCH transmission area, and a terminal performing transmission through the remaining slots in which the corresponding area exists can leave the corresponding area empty and transmit. 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 arrangement of the resource pool can 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 UE transmits HARQ feedback information among a set of PRBs based on configuration information for frequency resources in the resource pool. One for PSFCH used to transmit More than one PRB can be determined. In addition, the UE may determine the number of PSFCH resources used to transmit HARQ feedback information.

When the 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 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 an SCI including resource allocation information for PSSCH transmission.

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

When a 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 mutual interference. Signals generated through this may be orthogonal to each other so that interference is minimized.

For example, when many signals overlap, since the noise of the sum of interference signals becomes too large to be ignored, in an environment where interference control is important, a different cyclic shift may be applied for each terminal with respect to a specific sequence so that the mutual correlation characteristic becomes 0. .

All terminals sharing the PSFCH resource have a common symbol length and sequence number value depending on preset values. According to an example, when the 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 a 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 the PSSCH. For example, the ID of the receiving terminal receiving the PSSCH may be indicated by a higher layer. The ID of another UE that has transmitted the PSSCH may be provided by SCI including scheduling information for the PSSCH. That is, separate cyclic shifts may be determined based on the case where HARQ feedback information for PSSCH reception in each terminal is ACK and NACK, in addition to ID information of terminals transmitting and receiving PSSCH.

Accordingly, the terminal may transmit a signal generated for HARQ feedback information on the received PSSCH through the PSFCH resource determined from the resource pool. In this case, according to an example, transmission of the HARQ feedback information may be performed based on timing gap information between reception of the PSSCH and transmission of the HARQ feedback information for reception of the 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.

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

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

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

Embodiment 1: Signal generation transmitted over PSFCH

The present disclosure provides a Zadoff-Chu sequence capable of extracting some degree of interference improvement performance due to low interference characteristics in a sidelobe even in an environment in which orthogonality is not guaranteed due to basically mixed incoming signals and misalignment. provides a way to use it.

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

can be used. 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 using the Zadoff-Chu sequence in PSFCH, the following method may be applied. First, different α (phase shift) values between different terminals are not supported. This is because timing cannot be guaranteed and signals must be identified only with intensity values rather than phase values. In addition, empty spaces for guard bands are formed above and below. For example, even if two RBs are used, signals are distributed only to REs smaller than 24. A guard period (GP) can be introduced, but an automatic gain control (AGC) and a reference signal (RS) are not separately introduced because they may cause additional interference. Specifically, the following methods may be additionally applied.

However, the following description is made on the assumption 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 support PSFCH transmission and reception maintaining orthogonality in a situation where the distance between terminals is large and an error greater than that of the existing CP occurs, the base station sets the number of symbols of the PSFCH to a value greater than 1 and sets the corresponding area to CP. can In the case of an environment in which transmission is performed at 15 kHz SCS (subcarrier spacing) as an embodiment, the CP length c and the symbol length u according to the number s of the PSFCH symbols 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

When a reception point (RP) uses an extended cyclic prefix (ECP) for 60 kHz SCS, the CP length c and symbol length u according to the number s of the PSFCH symbols set by the base station are set to be as follows 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, transmission and reception is possible without damaging the original orthogonality of Zadoff-Chu.

② Overlapping PSSCH and PSFCH

This method does not designate a physically separated PSFCH and perform rate matching by adjusting the PSSCH to the designated PSFCH, but adjusts the transmission power of the symbols of the PSFCH to provide feedback at a preset location in the PSSCH area It is a way to transmit a control message. That is, a method in which a PSSCH signal sent by any device A, a PSFCH signal sent by device B, and a PSFCH signal sent by device C can coexist on the same time/frequency resource. However, PSSCHs of different terminals cannot coexist. In this case, the receiving terminal receiving the PSSCH may treat other signals transmitted through the PSFCH as interference noise and receive them, or may attempt to detect the PSFCH and then remove the corresponding component. The transmitting terminal may also take an action such as predicting a corresponding situation and selecting a lower modulation coding scheme (MCS) level in advance.

For this operation, the transmission power value of the PSFCH may be separately preset. That is, the transmit power value of the PSFCH may be set to a predetermined ratio or difference from the current PSSCH or PSCCH transmit power, or may be set to an explicit value, or set only the maximum or minimum value and allow the terminal to transmit arbitrarily. You may.

Embodiment 2: Setting Parameters for PSFCH Message Generation

에서 유저 별로 다른 u를 사용한다.The operation of the Zadoff-Chu sequence in a general code-based multiplexing environment uses a method that allows different terminals to use different seed sequences so that the cross-correlation characteristics stop at less than the square root of the length. in other words,

In , different u is used for each user.

However, when many signals overlap, the noise of the sum of the interference signals becomes too large to be ignored. Therefore, in an environment where interference control is important, the cyclic shift of a specific sequence in which the mutual correlation characteristic becomes 0 is assigned, that is, the terminal A method of using a different δ may also be used. Specifically, the following method may be applied. For smooth description, FIG. 17 describes a PSFCH structure defined as period 4 as an example, but substantially the same method may be applied to all periods.

① Use only single u,v

All UEs sharing PSFCH resources have common u and v values depending on preset values. Here, the possible cyclic shift (δ) value depends on the sequence length 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, it is possible to allocate according to each. For example, the following allocation 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 that is one or more predetermined or determined depending on p.

, NACK일 때

(또는 그 반대)(1) When ACK

, when NACK

(or vice versa)

, NACK일 때

(또는 그 반대) (2) When ACK

, when NACK

(or vice versa)

, NACK일 때

(또는 그 반대)(3) In case of ACK

, when NACK

(or vice versa)

, NACK일 때

(또는 ACK일 때

, NACK일 때

)(4) When ACK

, when NACK

(or when ACK

, when NACK

)

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

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

② Users use different u and v

This method is a method of using different values of u and v according to the terminal ID and the set value in the same way as the conventional method. At this time, in the method provided by the present disclosure, when the PSFCH is applied to only one RBG among several RBGs, PSCCH-using terminals of the same time or frequency share the same u and v, and in each case, the same frequency or the same frequency. This is a method of allocating the same δ to the 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 method ①.

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

In addition, the present disclosure may further provide (1) a method for managing a resource pool in which a PSFCH region is separately defined and (2) a method for transmitting information on whether a PSFCH region exists through a DCI or SCI region.

Hereinafter, the scheduling UE (S-UE) manages sidelink transmission resources between the UEs it manages and allocates them 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 transmission resources within preset time/frequency resources by a base station or the like and delivers them to a transmitter UE of a corresponding link. In addition, the scheduling indication message means 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 DCI/SCI form. In addition, the sidelink control message refers to a message including time/frequency and MCS information of a data area, which is transmitted from a sender terminal to a receiver terminal.

Third Embodiment: Resource pool operation in which PSFCH areas are separately defined

According to an example, a 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 configuring a resource pool through RRC, but may be additionally set in a pre-designated resource pool through dedicated RRC and may be divided and defined as needed. For example, a frequency location may be defined when configuring a resource pool, and the number of symbols may be configured through additional information. Alternatively, a region to be actually activated, that is, to be used as an actual PSFCH among PSFCH configurable regions, can be additionally set among defined location regions used in the initial configuration.

Specifically, a PSFCH transmittable region may be activated/deactivated in a resource pool previously designated through RRC. For a transport block transmitted for broadcast or the like, or when it is configured not to perform an HARQ procedure, the use of the PSFCH is unnecessary. Accordingly, when the transmission method is configured semi-statically 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 may be indicated through additional RRC or the like. This region may be delivered in the form of a PSFCH activation region or indirectly in the form of a transport region supporting HARQ.

4th Embodiment: Transmission of information on whether a PSFCH region exists through DCI and SCI regions

The PSFCH area configured and activated by RRC becomes an area that all terminals using the corresponding resource pool cannot use for PSSCH transmission. In this case, if the number of preset PSFCH regions is small, a sufficient amount of PSFCH may not be utilized, and if the number of preset PSFCH regions is large, resources may be wasted. Therefore, a method may be considered in which only the actually allocated region is excluded from transmission resources by transferring information related to the region in which PSFCH transmission is to be performed to the terminal using the corresponding slot. Specifically, the following methods can be used.

When the scheduler indicates transmission resources, information on the location of an RB with a PSFCH and the number of symbols may be delivered. Based on PSFCH usage information known to the base station or scheduling terminal, when the slot in which the corresponding transmission is made is instructed to other terminals as a sidelink transmission interval, information related to the area in which PSFCH transmission is to be performed is delivered together, so that the transmitting terminal This is a method for constructing a transport block excluding the corresponding resource interval.

Alternatively, a group common control message may be used. This is a method in which the scheduler group-casts which PSFCH is allocated/used in a specific sidelink resource pool to all sidelink using terminals in every slot or every 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 obtained through the group common control message and the scheduling indication message received by the transmitting terminal. In this case, the receiving terminal may reconfigure the transmission region 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 corresponding message may depend on the number of PSFCHs in the resource pool.

In addition, the area indicated by the corresponding format may be the same as the slot in which the corresponding DCI is transmitted, and may have a difference by DCI-SCI gap + alpha in order to utilize the corresponding information in the transmitting end. Here, the DCI-SCI gap means a slot distance between a control channel through which a DCI message or an SCI message in which a scheduling user delivers a scheduling indication message is transmitted and a PSCCH through which the transmitting terminal transmits the SCI. can be set in common. Alpha can be a value specified by the specification, and may not be necessary in general.

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

Unless otherwise specified, the above-described first to fourth embodiments and each sub-method may be applied independently of each other or may be applied in combination with each other.

According to this, it is possible to effectively manage PSFCH transmission resources, and effectively manage PSFCH transmission resources without deterioration of 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 present embodiments described with reference to FIGS. 1 to 17 will be described with reference to the drawings.

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

Referring to FIG. 18 , a terminal 1800 according to another embodiment includes a controller 1810, a transmitter 1820, and a receiver 1830.

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

The receiving unit 1830 may receive configuration information about 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 for transmitting and receiving a PSCCH, a PSSCH, and the like 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 control unit 1810 may generate a signal for transmitting HARQ feedback information on a PSSCH received from another terminal based on a sequence associated with a 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 UE transmitting the PSSCH. Accordingly, the controller 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 an SCI including resource allocation information for PSSCH transmission.

The control unit 1810 may use a sequence associated with a resource pool for sidelink transmission to generate a signal for transmitting configured HARQ feedback information. According to an example, the configuration information for the resource pool received from the base station may include information on a sequence configured in advance 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 in order to minimize mutual interference. For example, when many signals overlap, since the noise of the sum of interference signals becomes too large to be ignored, in an environment where interference control is important, a different cyclic shift may be applied for each terminal with respect to a specific sequence so that the mutual correlation characteristic becomes 0. .

All terminals sharing the PSFCH resource have a common symbol length and sequence number value depending on preset values. In this case, according to an example, possible cyclic shift values may depend on the length of the sequence. For example, when the length of the sequence is 12, 12 types of cyclic shift values may be used. In addition, according to an example, when the 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 a 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 the PSSCH. For example, the ID of the receiving terminal receiving the PSSCH may be indicated by a higher layer. The ID of another UE that has transmitted the PSSCH may be provided by SCI including scheduling information for the PSSCH. That is, separate cyclic shifts may be determined based on the case where HARQ feedback information for PSSCH reception in each terminal is ACK and NACK, in addition to ID information of terminals transmitting and receiving PSSCH.

The transmitter 1820 may transmit the generated signal through a physical sidelink feedback channel (PSFCH) in 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. The receiving unit 1830 may receive configuration information about a frequency resource through which a PSFCH can be transmitted within a resource pool.

According to an example, a frequency resource for PSFCH transmission may be composed of 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 PSFCHs are required to correspond to one transport block, transport zones do not need to be configured for every RB. That is, during initial transmission, the PSFCH is set to be transmitted only to a location corresponding to one PSCCH transmission area, and a terminal performing transmission through the remaining slots in which the corresponding area exists can leave the corresponding area empty and transmit. 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 arrangement of the resource pool can be determined through this.

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

In addition, 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. In this case, according to an example, transmission of the PSFCH may be performed in the first slot including the PSFCH resource in the resource pool after the last slot of PSSCH reception.

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

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

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

Referring to FIG. 19 , a base station 1900 according to another embodiment includes a controller 1910, a transmitter 1920, and a receiver 1930.

The control unit 1910 controls overall operations of the base station 1900 according to a method for the base station to control transmission of HARQ feedback information for sidelink transmission of a terminal necessary for performing the above-described present invention. 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 to and from the terminal.

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

The transmitter 1920 may transmit configuration information on PSFCH resources 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 about a frequency resource through which a PSFCH can be transmitted within a resource pool.

According to an example, a frequency resource for PSFCH transmission may be composed of 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 PSFCHs are required to correspond to one transport block, transport zones do not need to be configured for every RB. That is, during initial transmission, the PSFCH is set to be transmitted only to a location corresponding to one PSCCH transmission area, and a terminal performing transmission through the remaining slots in which the corresponding area exists can leave the corresponding area empty and transmit. 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 arrangement of the resource pool can 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 UE transmits HARQ feedback information among a set of PRBs based on configuration information for frequency resources in the resource pool. One for PSFCH used to transmit More than one PRB can be determined. In addition, the UE may determine the number of PSFCH resources used to transmit HARQ feedback information.

When the 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 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 an SCI including resource allocation information for PSSCH transmission.

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

When a 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 mutual interference. Signals generated through this may be orthogonal to each other so that interference is minimized.

For example, when many signals overlap, since the noise of the sum of interference signals becomes too large to be ignored, in an environment where interference control is important, a different cyclic shift may be applied for each terminal with respect to a specific sequence so that the mutual correlation characteristic becomes 0. .

All terminals sharing the PSFCH resource have a common symbol length and sequence number value depending on preset values. According to an example, when the 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 a 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 the PSSCH. For example, the ID of the receiving terminal receiving the PSSCH may be indicated by a higher layer. The ID of another UE that has transmitted the PSSCH may be provided by SCI including scheduling information for the PSSCH. That is, separate cyclic shifts may be determined based on the case where HARQ feedback information for PSSCH reception in each terminal is ACK and NACK, in addition to ID information of terminals transmitting and receiving PSSCH.

Accordingly, the terminal may transmit a signal generated for HARQ feedback information on the received PSSCH through the PSFCH resource determined from the resource pool. In this case, according to an example, transmission of the HARQ feedback information may be performed based on timing gap information between reception of the PSSCH and transmission of the HARQ feedback information for reception of the 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.

According to this, it is possible to provide a specific method and apparatus capable of generating a signal transmitted through the 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, which are wireless access systems. That is, among the present embodiments, steps, configurations, and parts not described to clearly reveal the present technical idea may be supported by the above-mentioned standard documents. In addition, all terms disclosed in this specification can be explained by the standard documents disclosed above.

The present embodiments described above may 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 hardware implementation, the method according to the present embodiments includes one or more ASICs (Application Specific Integrated Circuits), DSPs (Digital Signal Processors), DSPDs (Digital Signal Processing Devices), PLDs (Programmable Logic Devices), FPGAs (Field Programmable Gate Arrays), processors, controllers, microcontrollers, or microprocessors.

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

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

The above description is merely illustrative of the technical idea of the present disclosure, and various modifications and variations can be made to those skilled in the art without departing from the essential characteristics of the technical idea. In addition, since the present embodiments are not intended to limit the technical idea of the present disclosure, but to explain, the scope of the present 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 rights of the present disclosure.

Claims (16)

In a method for a terminal to transmit HARQ feedback information for sidelink transmission,
Receiving configuration information about a resource pool for sidelink transmission;
Generating a signal for transmitting HARQ feedback information for a physical sidelink shared channel (PSSCH) received from another terminal based on a sequence to which a sequence parameter according to the resource of the resource pool is applied step; and
Transmitting the generated signal through a sidelink feedback channel (PSFCH) in the resource pool,
Further comprising receiving configuration information for PSFCH resources including information on a set of physical resource blocks (PRBs) for transmission of the PSFCH in the resource pool,
Transmitting the generated signal may include transmitting the generated signal through a PSFCH resource determined based on configuration information for the PSFCH resource in the resource pool;
The signal for transmitting the HARQ feedback information is generated by applying a cyclic shift value to a sequence associated with the resource pool,
The cyclic shift value is applied to the sequence based on the ID of the terminal, the ID of the other terminal, and the value of HARQ feedback information for the PSSCH,
The HARQ feedback information,
A method transmitted based on timing gap information between reception of the PSSCH received through higher layer signaling and transmission of the HARQ feedback information for reception of the PSSCH. delete delete According to claim 1,
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 about a resource pool for sidelink transmission; and
Transmitting configuration information for a Physical Sidelink Feedback Channel (PSFCH) resource within the resource pool,
The terminal is configured to transmit HARQ feedback information for a sidelink data channel (Physical Sidelink Shared Channel; PSSCH) received from another terminal based on a sequence to which a sequence parameter according to a resource of the resource pool is applied. generating a signal and transmitting the generated signal through the PSFCH;
The configuration information for the PSFCH resource includes configuration information for a set of physical resource blocks (PRBs) for transmission of the PSFCH in the resource pool,
The PSFCH resource is determined based on configuration information for the PSFCH resource in the resource pool,
The signal for transmitting the HARQ feedback information is generated by applying a cyclic shift value to a sequence associated with the resource pool,
The cyclic shift value is applied to the sequence based on the ID of the terminal, the ID of the other terminal, and the value of HARQ feedback information for the PSSCH,
The HARQ feedback information,
A method transmitted based on timing gap information between reception of the PSSCH received through higher layer signaling and transmission of the HARQ feedback information for reception of the PSSCH. delete delete According to claim 5,
The ID of the other terminal is,
A method provided by sidelink control information (SCI) including scheduling information for the PSSCH. In a terminal transmitting HARQ feedback information for sidelink transmission,
A receiving unit for receiving configuration information about a resource pool for sidelink transmission;
Generating a signal for transmitting HARQ feedback information for a physical sidelink shared channel (PSSCH) received from another terminal based on a sequence to which a sequence parameter according to the resource of the resource pool is applied control unit; and
A transmitter for transmitting the generated signal through a physical sidelink feedback channel (PSFCH) in the resource pool;
The receiving unit further receives configuration information for a PSFCH resource including information on a set of physical resource blocks (PRBs) for transmission of a PSFCH in a resource pool,
The transmitting unit transmits the generated signal through a PSFCH resource determined based on configuration information for the PSFCH resource in the resource pool,
The signal for transmitting the HARQ feedback information is generated by applying a cyclic shift value to a sequence associated with the resource pool,
The cyclic shift value is applied to the sequence based on the ID of the terminal, the ID of the other terminal, and the value of HARQ feedback information for the PSSCH,
The HARQ feedback information,
A terminal transmitted based on timing gap information between reception of the PSSCH received through higher layer signaling and transmission of the HARQ feedback information for reception of the PSSCH. delete delete According to claim 9,
The ID of the other terminal is,
A terminal provided by sidelink control information (SCI) including scheduling information for the PSSCH. In a base station that controls transmission of HARQ feedback information for sidelink transmission of a terminal,
A transmitter configured to transmit configuration information for a resource pool for sidelink transmission and configuration information for a Physical Sidelink Feedback Channel (PSFCH) resource within the resource pool,
The terminal is configured to transmit HARQ feedback information for a sidelink data channel (Physical Sidelink Shared Channel; PSSCH) received from another terminal based on a sequence to which a sequence parameter according to a resource of the resource pool is applied. generating a signal and transmitting the generated signal through the PSFCH;
The configuration information for the PSFCH resource includes configuration information for a set of physical resource blocks (PRBs) for transmission of the PSFCH in the resource pool,
The PSFCH resource is determined based on configuration information for the PSFCH resource in the resource pool,
The signal for transmitting the HARQ feedback information is generated by applying a cyclic shift value to a sequence associated with the resource pool,
The cyclic shift value is applied to the sequence based on the ID of the terminal, the ID of the other terminal, and the value of HARQ feedback information for the PSSCH,
The HARQ feedback information,
A base station transmitted based on timing gap information between reception of the PSSCH received through higher layer signaling and transmission of the HARQ feedback information for reception of the PSSCH. delete delete According to claim 13,
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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