KR20230080316A - Method of transmitting sidelink positioning reference signal and apparatus therefor - Google Patents

Abstract

An SL-PRS transmitting method performed in a first terminal comprises the following steps of: receiving setting information for transmission of an SL-PRS; and transmitting the SL-PRS based on the setting information. The setting information may include information indicating an SL slot(s) through which the SL-PRS is transmitted and symbols within the SL slot(s).

Description

Sidelink positioning signal transmission method and apparatus therefor {Method of transmitting sidelink positioning reference signal and apparatus therefor}

The present invention relates to positioning in a mobile communication system, and more particularly, to a method and apparatus for transmitting a sidelink positioning reference signal (PRS) in a mobile communication system.

The NR system introduced functions for supporting NR-based positioning technology from Release-16, and improvements were made to improve the performance of positioning technology from Release-17. However, the corresponding positioning technologies are all Uu link-based positioning technologies between the terminal and the base station, and sidelink-based positioning technologies are not yet supported in the NR system. Sidelink-based V2X services require sidelink-based positioning technology support for collision avoidance or location tracking, and these technologies support not only in-coverage situations but also out-of-coverage situations. ) should also be supported. In addition, sidelink-based positioning technology needs to be supported for sidelink-based public safety services and other services. In order to support sidelink-based positioning technology, transmission of a sidelink positioning reference signal (SL-PRS) for precise positioning may be required.

An object of the present invention to solve the above problems is an SL-PRS transmission method performed in a first terminal and a base station to which the first terminal is connected, a location management function (LMF), or sidelink positioning with the first terminal It is to provide a method for configuring SL-PRS transmission of a first terminal, which is performed in a second terminal belonging to a group of terminals performing

Another object of the present invention to solve the above problem is to provide a configuration of a device that performs the SL-PRS transmission method and the SL-PRS transmission setting method.

According to an embodiment of the present invention for achieving the above object, an SL-PRS transmission method performed in a first terminal includes: receiving configuration information for transmission of an SL-PRS; and transmitting the SL-PRS based on the configuration information, wherein the configuration information includes sidelink (SL) slot(s) through which the SL-PRS is transmitted and symbols within the SL slot(s) It may contain information pointing to them.

The SL slot(s) through which the SL-PRS is transmitted may be set independently of a resource pool for transmitting and receiving sidelink data or may be set in a separate resource pool for transmitting the SL-PRS.

In the first slot among the SL slot(s) in which the SL-PRS is transmitted, the SL-PRS is transmitted in the last N (N is a natural number equal to or greater than 1) symbol(s) excluding the last guard symbol of the first slot. transmitted, and the N number of symbol(s) may or may not include an automatic gain control (AGC) symbol.

The SL-PRS may be transmitted in a first frequency domain other than a frequency domain in which a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSSCH), and a physical sidelink broadcast channel (PSBCH) are transmitted.

The first frequency domain may be indicated by an index indicating a starting resource block (RB) or starting subchannel and the number of consecutive RBs or subchannels.

In the first frequency domain, the SL-PRS is mapped in a comb form according to the interval of D (D is a natural number of 2 or more) subcarriers, and the SL-PRS is transmitted in a plurality of symbols. In this case, the SL-PRS may be transmitted with a different frequency offset value applied to each symbol of the plurality of symbols.

The configuration information may be received from a first base station to which the first terminal is connected, a location management function (LMF), or a second terminal belonging to a group of terminals performing sidelink positioning with the first terminal.

From which communication node among the first base station, the LMF, and the second terminal the configuration information is received, the first terminal is in an in-coverage state or an out-of-coverage state. coverage) state and/or the configuration of the first base station.

The SL-PRS may be transmitted in a periodic transmission scheme, a semi-persistent periodic transmission scheme, or an aperiodic transmission scheme.

When a trigger indicator is received from the first base station or the second terminal, the SL-PRS is repeatedly transmitted a predetermined number of times in an aperiodic transmission scheme, and the predetermined number of times is included in a preset value and the configuration information It may be a signaled value, or a value signaled by a medium access control-control element (MAC-CE) or sidelink control information (SCI).

The configuration information further includes information on a periodicity and/or offset of the SL-PRS transmission, and when the SL-PRS is transmitted in the periodic transmission method, the SL-PRS transmission The period may be set to coincide with or be a multiple of the period of physical sidelink feedback channel (PSFCH) transmission.

Different offsets may be applied to a slot through which the SL-PRS is transmitted and a slot through which the PSFCH is transmitted, or the same offset may be applied to a slot through which the SL-PRS is transmitted and a slot through which the PSFCH is transmitted.

According to another embodiment of the present invention for achieving the above object, an operating method of a communication node configuring SL-PRS transmission includes: transmitting configuration information for SL-PRS transmission to a first terminal; and receiving a measurement result of the SL-PRS transmitted by the first terminal based on the configuration information from a group of terminals performing sidelink positioning with the first terminal, wherein the configuration information includes the The SL-PRS may include information indicating the transmitted sidelink (SL) slot(s) and symbols within the SL slot(s).

The SL slot(s) through which the SL-PRS is transmitted may be set independently of a resource pool for transmitting and receiving sidelink data or may be set in a separate resource pool for transmitting the SL-PRS.

The SL-PRS may be transmitted in a first frequency domain other than the frequency domain in which the PSCCH, PSSCH, and PSBCH are transmitted.

In the first frequency domain, the SL-PRS is mapped in a comb form according to the interval of D (D is a natural number of 2 or more) subcarriers, and the SL-PRS is transmitted in a plurality of symbols. In this case, the SL-PRS may be transmitted with a different frequency offset value applied to each symbol of the plurality of symbols.

The communication node may be a first base station to which the first terminal is connected, a location management function (LMF), or a second terminal belonging to a group of terminals performing sidelink positioning with the first terminal.

According to an embodiment of the present invention for achieving the above object, a first terminal performing SL-PRS transmission includes: a processor; and a transceiver controlled by the processor, wherein the processor includes: receiving configuration information for transmission of an SL-PRS through the transceiver; and transmitting the SL-PRS through the transceiver based on the setting information, wherein the setting information includes sidelink (SL) slot(s) through which the SL-PRS is transmitted and the SL It may include information indicating symbols in the slot(s).

The SL slot(s) through which the SL-PRS is transmitted may be set independently of a resource pool for transmitting and receiving sidelink data or may be set in a separate resource pool for transmitting the SL-PRS.

The SL-PRS is transmitted in a first frequency domain other than the frequency domain in which the PSCCH, PSSCH, and PSBCH are transmitted, and within the first frequency domain, the SL-PRS is an interval of D (D is a natural number equal to or greater than 2) subcarriers When the SL-PRS is transmitted in a plurality of symbols, a different frequency offset value is applied to each symbol of the plurality of symbols and can be transmitted.

According to an embodiment of the present invention, a sidelink positioning reference signal transmission method may be provided. Accordingly, the performance of the communication system can be improved.

1 is a conceptual diagram illustrating a first embodiment of a communication system.
2 is a block diagram showing a first embodiment of a communication node constituting a communication system.
3 is a conceptual diagram illustrating a first embodiment of a type 1 frame structure.
4 is a conceptual diagram illustrating a first embodiment of a type 2 frame structure.
5 is a conceptual diagram illustrating a first embodiment of a method of transmitting an SS/PBCH block in a communication system.
6 is a conceptual diagram illustrating a first embodiment of an SS/PBCH block in a communication system.
7 is a conceptual diagram illustrating a second embodiment of a method of transmitting an SS/PBCH block in a communication system.
8 is a conceptual diagram for explaining time domain transmission positions of SSBs according to subcarrier spacing and L.
9A is a conceptual diagram illustrating RMSI CORESET mapping pattern #1 in a communication system, FIG. 9B is a conceptual diagram illustrating RMSI CORESET mapping pattern #2 in a communication system, and FIG. 9C illustrates RMSI CORESET mapping pattern #3 in a communication system. It is a concept diagram.
10 is a conceptual diagram for explaining an example of setting a PSFCH within one slot.
11 is a conceptual diagram for explaining an example of configuring PSFCH resources according to a PSFCH transmission period.
12 is a conceptual diagram illustrating embodiments of a method of multiplexing a control channel and a data channel in sidelink communication.
13A and 13B are conceptual diagrams illustrating cases in which N number of symbol(s) for SL-PRS transmission is configured in an SL slot according to an embodiment of the present invention.
14 is a conceptual diagram illustrating an example in which a separate resource region for SL-PRS transmission is set in an SL resource pool according to an embodiment of the present invention.
15 is a conceptual diagram illustrating an example in which a resource pool for SL-PRS transmission is set separately from SL resource pools set for sidelink data transmission and reception according to an embodiment of the present invention.
16 is a conceptual diagram for explaining SL-PRS sequence mapping within a resource region for SL-PRS transmission according to an embodiment of the present invention.
17 is a conceptual diagram illustrating a case in which a collision occurs between a slot in which an SL-PRS is transmitted and a slot in which a PSFCH is transmitted according to an embodiment of the present invention.

Since the present invention can make various changes and have various embodiments, specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. These terms are only used for the purpose of distinguishing one component from another. For example, a first element may be termed a second element, and similarly, a second element may be termed a first element, without departing from the scope of the present invention. The term "and/or" includes any combination of a plurality of related listed items or any of a plurality of related listed items.

In embodiments of the present application, “at least one of A and B” may mean “at least one of A or B” or “at least one of combinations of one or more of A and B”. Also, in the embodiments of the present application, “one or more of A and B” may mean “one or more of A or B” or “one or more of combinations of one or more of A and B”.

In embodiments of the present application, (re)transfer may mean “send”, “retransmit”, or “send and retransmit”, and (re)set may mean “set”, “reset”, or “set and "Reset", (re)connect can mean "connect", "reconnect", or "connect and reconnect", (re)connect can mean "connect", "reconnect", or "reconnect" connection and reconnection”.

It is understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, but other elements may exist in the middle. It should be. On the other hand, when an element is referred to as “directly connected” or “directly connected” to another element, it should be understood that no other element exists in the middle.

Terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "include" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in this application, they should not be interpreted in an ideal or excessively formal meaning. don't

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in more detail. In order to facilitate overall understanding in the description of the present invention, the same reference numerals are used for the same components in the drawings, and redundant descriptions of the same components are omitted.

A communication system to which embodiments according to the present invention are applied will be described. A communication system to which embodiments according to the present invention are applied is not limited to the contents described below, and embodiments according to the present invention can be applied to various communication systems. Here, the communication system may be used in the same sense as a communication network.

1 is a conceptual diagram illustrating a first embodiment of a communication system.

Referring to FIG. 1, a communication system 100 includes a plurality of communication nodes 110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130-4, 130-5, 130-6). In addition, the communication system 100 includes a core network (eg, a serving-gateway (S-GW), a packet data network (PDN)-gateway (P-GW), and a mobility management entity (MME)). can include more. When the communication system 100 is a 5G communication system (eg, a new radio (NR) system), the core network includes an access and mobility management function (AMF), a user plane function (UPF), a session management function (SMF), and the like. can include

The plurality of communication nodes 110 to 130 may support communication protocols (eg, LTE communication protocol, LTE-A communication protocol, NR communication protocol, etc.) defined in the 3rd generation partnership project (3GPP) standard. The plurality of communication nodes 110 to 130 are CDMA (code division multiple access) technology, WCDMA (wideband CDMA) technology, TDMA (time division multiple access) technology, FDMA (frequency division multiple access) technology, OFDM (orthogonal frequency division) multiplexing) technology, filtered OFDM technology, CP (cyclic prefix)-OFDM technology, DFT-s-OFDM (discrete Fourier transform-spread-OFDM) technology, OFDMA (orthogonal frequency division multiple access) technology, SC (single carrier)-FDMA technology, NOMA (Non-orthogonal Multiple Access) technology, GFDM (generalized frequency division multiplexing) technology, FBMC (filter bank multi-carrier) technology, UFMC (universal filtered multi-carrier) technology, SDMA (Space Division Multiple Access) technology, etc. can support Each of the plurality of communication nodes may have the following structure.

2 is a block diagram showing a first embodiment of a communication node constituting a communication system.

Referring to FIG. 2 , a communication node 200 may include at least one processor 210, a memory 220, and a transceiver 230 connected to a network to perform communication. In addition, the communication node 200 may further include an input interface device 240, an output interface device 250, a storage device 260, and the like. Each component included in the communication node 200 may be connected by a bus 270 to communicate with each other.

However, each component included in the communication node 200 may be connected through an individual interface or an individual bus centered on the processor 210 instead of the common bus 270 . For example, the processor 210 may be connected to at least one of the memory 220, the transmission/reception device 230, the input interface device 240, the output interface device 250, and the storage device 260 through a dedicated interface. .

The processor 210 may execute a program command stored in at least one of the memory 220 and the storage device 260 . The processor 210 may refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present invention are performed. Each of the memory 220 and the storage device 260 may include at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 220 may include at least one of a read only memory (ROM) and a random access memory (RAM).

Referring back to FIG. 1, the communication system 100 includes a plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2), a plurality of terminals 130- 1, 130-2, 130-3, 130-4, 130-5, 130-6). Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 may form a macro cell. Each of the fourth base station 120-1 and the fifth base station 120-2 may form a small cell. The fourth base station 120-1, the third terminal 130-3, and the fourth terminal 130-4 may belong to the cell coverage of the first base station 110-1. The second terminal 130-2, the fourth terminal 130-4, and the fifth terminal 130-5 may belong to the cell coverage of the second base station 110-2. The fifth base station 120-2, the fourth terminal 130-4, the fifth terminal 130-5, and the sixth terminal 130-6 may belong to the cell coverage of the third base station 110-3. there is. The first terminal 130-1 may belong to the cell coverage of the fourth base station 120-1. The sixth terminal 130-6 may belong to the cell coverage of the fifth base station 120-2.

Here, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 is a NodeB (NB), an evolved NodeB (eNB), a gNB, an advanced base station (ABS), and a HR -BS (high reliability-base station), BTS (base transceiver station), radio base station, radio transceiver, access point, access node, radio access station (RAS) ), MMR-BS (mobile multihop relay-base station), RS (relay station), ARS (advanced relay station), HR-RS (high reliability-relay station), HNB (home NodeB), HeNB (home eNodeB), It may be referred to as a road side unit (RSU), a radio remote head (RRH), a transmission point (TP), a transmission and reception point (TRP), and the like.

Each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 includes user equipment (UE), terminal equipment (TE), advanced mobile station (AMS), HR-MS (high reliability-mobile station), terminal, access terminal, mobile terminal, station, subscriber station, mobile station, mobile It may be referred to as a portable subscriber station, a node, a device, an on board unit (OBU), and the like.

Meanwhile, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may operate in different frequency bands or may operate in the same frequency band. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to each other through an ideal backhaul link or a non-ideal backhaul link, and , information can be exchanged with each other through an ideal backhaul link or a non-ideal backhaul link. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to the core network through an ideal backhaul link or a non-ideal backhaul link. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 transmits a signal received from the core network to a corresponding terminal 130-1, 130-2, 130-3, and 130 -4, 130-5, 130-6), and signals received from corresponding terminals 130-1, 130-2, 130-3, 130-4, 130-5, 130-6 are transmitted to the core network can be sent to

In addition, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 transmits MIMO (eg, single user (SU)-MIMO, multi-user (MU)- MIMO, massive MIMO, etc.), coordinated multipoint (CoMP) transmission, carrier aggregation (CA) transmission, transmission in an unlicensed band, direct communication between devices (device to device communication, D2D) (or , proximity services (ProSe)), Internet of Things (IoT) communication, dual connectivity (DC), etc. may be supported. Here, each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 is a base station 110-1, 110-2, 110-3, 120-1 , 120-2) and operations supported by the base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be performed. For example, the second base station 110-2 can transmit a signal to the fourth terminal 130-4 based on the SU-MIMO scheme, and the fourth terminal 130-4 uses the SU-MIMO scheme. A signal may be received from the second base station 110-2. Alternatively, the second base station 110-2 may transmit a signal to the fourth terminal 130-4 and the fifth terminal 130-5 based on the MU-MIMO scheme, and the fourth terminal 130-4 And each of the fifth terminal 130-5 may receive a signal from the second base station 110-2 by the MU-MIMO method.

Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 may transmit a signal to the fourth terminal 130-4 based on the CoMP scheme, and The terminal 130-4 may receive signals from the first base station 110-1, the second base station 110-2, and the third base station 110-3 by CoMP. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 includes a terminal 130-1, 130-2, 130-3, and 130-4 belonging to its own cell coverage. , 130-5, 130-6) and a CA method. Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 controls D2D between the fourth terminal 130-4 and the fifth terminal 130-5. and each of the fourth terminal 130-4 and the fifth terminal 130-5 may perform D2D under the control of the second base station 110-2 and the third base station 110-3, respectively. .

Meanwhile, the communication system may support three types of frame structures. The type 1 frame structure can be applied to a frequency division duplex (FDD) communication system, the type 2 frame structure can be applied to a time division duplex (TDD) communication system, and the type 3 frame structure can be applied to an unlicensed band-based communication system (eg For example, it may be applied to a licensed assisted access (LAA) communication system.

3 is a conceptual diagram illustrating a first embodiment of a type 1 frame structure.

Referring to FIG. 3 , a radio frame 300 may include 10 subframes, and each subframe may include 2 slots. Accordingly, the radio frame 300 may include 20 slots (eg, slot #0, slot #1, slot #2, slot #3, ..., slot #18, slot #19). The radio frame 300 may have a length (Tf) of 10 ms (millisecond), a subframe length of 1 ms, and a slot length (T _slot ) of 0.5 ms. Here, Ts may indicate a sampling time and may be 1/30,720,000s (second).

A slot may consist of a plurality of OFDM symbols in the time domain and may consist of a plurality of resource blocks (RBs) in the frequency domain. A resource block may be composed of a plurality of subcarriers in the frequency domain. The number of OFDM symbols constituting a slot may vary depending on the configuration of a cyclic prefix (CP). CP may be classified into a normal CP and an extended CP. If a normal CP is used, a slot may consist of 7 OFDM symbols, and in this case, a subframe may consist of 14 OFDM symbols. If the extended CP is used, a slot may consist of 6 OFDM symbols, and in this case, a subframe may consist of 12 OFDM symbols.

4 is a conceptual diagram illustrating a first embodiment of a type 2 frame structure.

Referring to FIG. 4 , a radio frame 400 may include two half frames, and each half frame may include five subframes. Accordingly, the radio frame 400 may include 10 subframes. The length (Tf) of the radio frame 400 may be 10 ms. The length of the half frame may be 5 ms. The subframe length may be 1 ms. Here, Ts may be 1/30,720,000s.

The radio frame 400 may include a downlink subframe, an uplink subframe, and a special subframe. Each of the downlink subframe and the uplink subframe may include two slots. The slot length (T _slot ) may be 0.5 ms. Among the subframes included in the radio frame 400, each of subframe #1 and subframe #6 may be a special subframe. For example, when the downlink-uplink switching period is 5 ms, the radio frame 400 may include two special subframes. Alternatively, when the downlink-uplink switching period is 10 ms, the radio frame 400 may include one special subframe. The special subframe may include a downlink pilot time slot (DwPTS), a guard period (GP), and an uplink pilot time slot (UpPTS).

The downlink pilot time slot may be regarded as a downlink interval and may be used for cell search of the terminal, acquisition of time and frequency synchronization, channel estimation, and the like. The guard period may be used to solve an interference problem of uplink data transmission caused by a downlink data reception delay. In addition, the guard period may include a time required for switching from a downlink data reception operation to an uplink data transmission operation. The uplink pilot time slot may be used for uplink channel estimation, time and frequency synchronization acquisition, and the like. Transmission of a physical random access channel (PRACH) or a sounding reference signal (SRS) may be performed in an uplink pilot time slot.

Lengths of each of the downlink pilot time slot, guard period, and uplink pilot time slot included in the special subframe may be variably adjusted as needed. Also, the number and location of each of the downlink subframes, uplink subframes, and special subframes included in the radio frame 400 may be changed as needed.

In a communication system, a transmission time interval (TTI) may be a basic time unit for transmitting coded data through a physical layer. A short TTI may be used to support low latency requirements in a communication system. The length of the short TTI may be less than 1 ms. An existing TTI having a length of 1 ms may be referred to as a base TTI or a regular TTI. That is, the basic TTI may consist of one subframe. To support transmission in basic TTI units, signals and channels may be set in units of subframes. For example, a cell-specific reference signal (CRS), a physical downlink control channel (PDCCH), a physical downlink shared channel (PDSCH), a physical uplink control channel (PUCCH), and a physical uplink shared channel (PUSCH) exist for each subframe. can

On the other hand, synchronization signals (eg, primary synchronization signal (PSS), secondary synchronization signal (SSS)) may exist every 5 subframes, and a physical broadcast channel (PBCH) may exist every 10 subframes. And radio frames can be distinguished by SFN, and SFN is a signal whose transmission period is longer than one radio frame (eg, a paging signal, a reference signal for channel estimation, a signal indicating channel state information, etc.) can be used to define the transmission of The period of SFN may be 1024.

In the LTE system, the PBCH may be a physical layer channel used for transmission of system information (eg, master information block (MIB)). PBCH may be transmitted every 10 subframes. That is, the transmission period of the PBCH may be 10 ms, and the PBCH may be transmitted once in a radio frame. The same MIB may be transmitted during 4 consecutive radio frames, and after 4 consecutive radio frames, the MIB may be changed according to the situation of the LTE system. The transmission period of the same MIB may be referred to as "PBCH TTI", and the PBCH TTI may be 40 ms. That is, the MIB may be changed for each PBCH TTI.

MIB may consist of 40 bits. Among the 40 bits constituting the MIB, 3 bits may be used to indicate the system bandwidth, 3 bits may be used to indicate PHICH (physical hybrid automatic repeat request (ARQ) indicator channel) related information, and 8 bits may be used to indicate It can be used to indicate SFN, 10 bits can be set as reserved bits, and 16 bits can be used for cyclic redundancy check (CRC).

The SFN that distinguishes the radio frame may consist of a total of 10 bits (B9 to B0), and among the 10 bits, 8 bits (B9 to B2) of the most significant bit (MSB) may be indicated by the PBCH (ie, MIB) . MSB 8 bits (B9 to B2) of SFN indicated by PBCH (ie, MIB) may be the same during 4 consecutive radio frames (ie, PBCH TTI). The least significant bit (LSB) 2 bits (B1-B0) of SFN may change during 4 consecutive radio frames (i.e., PBCH TTI) and may not be explicitly indicated by the PBCH (i.e., MIB). there is. LSB 2 bits (B1 to B0) of SFN may be implicitly indicated by a scrambling sequence for PBCH (hereinafter, referred to as "PBCH scrambling sequence").

As the PBCH scrambling sequence, a gold sequence generated by initialization with a cell ID may be used, and the PBCH scrambling sequence may be initialized every 4 consecutive radio frames (ie, PBCH TTI) according to mod(SFN,4). there is. A PBCH transmitted in a radio frame corresponding to an SFN in which LSB 2 bits (B1 to B0) are set to “00” may be scrambled by a Gold sequence generated by initialization with a cell ID. Subsequently, the gold sequences generated according to mod(SFN,4) are used to scramble the PBCH transmitted in radio frames in which the LSB 2 bits (B1 to B0) of SFN are “01”, “10” and “11”. can

Therefore, in the initial cell search process, the UE acquires the cell ID through the PBCH scrambling sequence in the PBCH (ie, MIB) decoding process to obtain the values of the LSB 2 bits (B1 to B0) of the SFN (e.g., "00", " 01", "10", "11") can be found implicitly. The UE uses the LSB 2 bits (B1 to B0) of the SFN identified based on the PBCH scrambling sequence and the MSB 8 bits (B9 to B2) of the SFN indicated by the PBCH (ie MIB). You can check all bits (B9~B0)).

A mobile communication network that has evolved after LTE must satisfy technical requirements for supporting more diverse service scenarios as well as high transmission rates, which have been a major concern in the past. Recently, the ITU-R defined key performance indicators (KPIs) and requirements for IMT-2020, the official name of 5G mobile communication, which includes high transmission speed (eMBB, enhanced Mobile BroadBand), short transmission delay It is summarized as time (URLLC, Ultra Reliable Low Latency Communication), and massive terminal connectivity (mMTC, massive Machine Type Communication). According to the ITU-R projected schedule, it aims to allocate frequencies for IMT-2020 in 2019 and complete international standard approval by 2020.

3GPP is developing a new Radio Access Technology (RAT)-based 5G standard that meets the IMT-2020 requirements. According to the definition of 3GPP, the new radio access technology is a radio access technology that does not have backward compatibility with the existing 3GPP radio access technology, and a new wireless communication system after LTE adopting this radio access technology. In , it will be called NR (New Radio).

One of the characteristics that NR differs from CDMA or LTE, which are conventional 3GPP systems, is that it utilizes a wide range of frequency bands to increase transmission capacity. In this regard, WRC-15 supervised by ITU sets the agenda for the next WRC-19 to review the 24.25-86 GHz band as a candidate frequency band for IMT-2020. In 3GPP, bands from less than 1 GHz to 100 GHz are considered as NR candidate bands.

As waveform technologies for NR, OFDM (Orthogonal Frequency Division Multiplexing), Filtered OFDM, GFDM (Generalized Frequency Division Multiplexing), FBMC (Filter Bank Multi-Carrier), UFMC (Universal Filtered Multi-Carrier), etc. are discussed as candidate technologies. It is becoming. Although each has advantages and disadvantages, CP (Cyclic prefix)-based OFDM and SC-FDMA (Single Carrier-Frequency Division Multiple Access) have relatively low implementation complexity of the transceiver and multiple-input multiple-output (MIMO) scalability. It is still an effective method for 5G systems. However, in order to flexibly support various 5G usage scenarios, a method of simultaneously accommodating different Waveform parameters in one carrier without a guard band can be considered. To this end, out-of-band emission Filtered OFDM or GFDM having a low frequency spectrum (Out of Band Emission, OOB) may be suitable.

In the present invention, CP-based OFDM is assumed as a waveform technology for wireless access for convenience of description. However, this is only for convenience of description, and various embodiments of the present invention are not limited to a specific Waveform technology. In general, the category of CP-based OFDM technology includes Filtered OFDM or Spread Spectrum OFDM (eg, DFT-spread OFDM) technology.

A subcarrier spacing of a communication system (eg, an OFDM-based communication system) may be determined based on a carrier frequency offset (CFO) or the like. CFO may be caused by a Doppler effect, phase drift, or the like, and may increase in proportion to an operating frequency. Therefore, in order to prevent performance degradation of the communication system due to the CFO, the subcarrier spacing may increase in proportion to the operating frequency. On the other hand, CP overhead may increase as the subcarrier spacing increases. Accordingly, the subcarrier interval may be set based on channel characteristics according to frequency bands, radio frequency (RF) characteristics, and the like.

In the NR system, various numerologies are considered. For example, the subcarrier spacing of the communication system may be set to 15 kHz, 30 kHz, 60 kHz or 120 kHz. The subcarrier spacing of the LTE system may be 15 kHz, and the subcarrier spacing of the NR system may be 1, 2, 4, or 8 times the existing subcarrier spacing of 15 kHz. When the subcarrier spacing increases in units of powers of 2 of the existing subcarrier spacing, the frame structure can be easily designed.

The communication system may support a wide frequency band (eg, several hundred MHz to several tens of GHz). Since diffraction and reflection characteristics of radio waves are not good in a high frequency band, propagation loss (eg, path loss, reflection loss, etc.) in a high frequency band may be greater than propagation loss in a low frequency band. Accordingly, cell coverage of a communication system supporting a high frequency band may be smaller than cell coverage of a communication system supporting a low frequency band. In order to solve this problem, a beamforming method based on a plurality of antenna elements may be used to increase cell coverage in a communication system supporting a high frequency band.

The beamforming method may include a digital beamforming method, an analog beamforming method, a hybrid beamforming method, and the like. In a communication system using a digital beamforming method, a beamforming gain may be obtained using a plurality of RF paths based on a digital precoder or codebook. In a communication system using an analog beamforming method, a beamforming gain is obtained through an analog RF device (eg, a phase shifter, a power amplifier (PA), a variable gain amplifier (VGA), etc.) and an antenna array. can

Since the digital beamforming method requires expensive digital to analog converters (DACs) or analog to digital converters (ADCs) and transceiver units corresponding to the number of antenna elements, an antenna to increase beamforming gain Implementation complexity may increase. Since a plurality of antenna elements are connected to one transceiver unit through a phase shifter in a communication system using an analog beamforming method, the complexity of antenna implementation may not significantly increase even when a beamforming gain is increased. However, beamforming performance of a communication system using an analog beamforming method may be lower than beamforming performance of a communication system using a digital beamforming method. Also, since the phase shifter is adjusted in the time domain in a communication system using an analog beamforming method, frequency resources may not be efficiently used. Therefore, a hybrid beamforming method, which is a combination of a digital method and an analog method, may be used.

When cell coverage is increased by the use of the beamforming method, a common control channel and a common signal (eg, a reference signal, a synchronization signal) for all UEs belonging to the cell coverage as well as a control channel and a data channel of each of the UEs Also, it may be transmitted based on a beamforming scheme. In the case of transmitting a common control channel and signal to all terminals while increasing cell coverage by applying beamforming, it is difficult to transmit a common control channel and signal to all cell coverage in one transmission. A common control channel and signal must be transmitted through multiple beams. Transmitting a plurality of beams over a period of time while changing a plurality of beams in this way is called beam sweeping. When beamforming is applied to transmit a common control channel and a signal, such a beam sweeping operation is necessarily required.

A terminal accessing the system can acquire downlink frequency/time synchronization and cell ID information using a synchronization signal, obtain uplink synchronization through a random access procedure, and form a radio link. At this time, in the NR system, a synchronization block/physical broadcast channel (SS/PBCH) block may also be transmitted using a beam sweeping method. The SS/PBCH block may be composed of PSS, SSS, PBCH, etc., and within the SS/PBCH block, PSS, SSS, and PBCH may be composed of time division multiplexing (TDM). The SS/PBCH block may also be referred to as "SS block (SSB)". One SS/PBCH block may be transmitted using N consecutive OFDM symbols. Here, N may be an integer of 4 or greater. The base station may periodically transmit the SS/PBCH block, and the terminal may obtain frequency/time synchronization, cell ID, system information, etc. based on the SS/PBCH block received from the base station. The SS/PBCH block may be transmitted as follows.

5 is a conceptual diagram illustrating a first embodiment of a method of transmitting an SS/PBCH block in a communication system.

Referring to FIG. 5, one or more SS/PBCH blocks within an SS/PBCH block burst set may be transmitted in a beam sweeping manner. Up to L SS/PBCH blocks can be transmitted within one SS/PBCH block burst set. L may be an integer of 2 or more and may be defined in the 3GPP standard. Depending on the system frequency range, L may vary. Within the SS/PBCH block burst set, SS/PBCH blocks may be positioned contiguously or dispersively. Consecutive SS/PBCH blocks may be referred to as "SS/PBCH block burst". The SS/PBCH block burst set may be repeated periodically, and system information (eg, MIB) transmitted through PBCHs of SS/PBCH blocks within the SS/PBCH block burst set may be the same. SS/PBCH block index, SS/PBCH block burst index, OFDM symbol index, slot index, etc. may be explicitly or implicitly indicated by the PBCH.

6 is a conceptual diagram illustrating a first embodiment of an SS/PBCH block in a communication system.

Referring to FIG. 6, the arrangement order in the SS/PBCH block may be “PSS → PBCH → SSS → PBCH”. Within the SS/PBCH block, PSS, SSS, and PBCH may be configured in a TDM manner. In the symbol where the SSS is located, the PBCH may be allocated to higher frequency resources and lower frequency resources than the SSS. When the maximum number of SS/PBCH blocks is 8 in a frequency band of 6 GHz or less, the index of the SS/PBCH block is based on a demodulation reference signal (DMRS) used for demodulation of the PBCH (hereinafter referred to as "PBCH DMRS"). can be confirmed with When the maximum number of SS/PBCH blocks is 64 in a frequency band of 6 GHz or higher, LSB 3 bits among 6 bits indicating the index of the SS/PBCH block can be checked based on the PBCH DMRS, and the remaining 3 bits MSB is the PBCH page. Can be identified based on load.

The maximum system bandwidth supportable in the NR system may be 400 MHz. The size of the maximum bandwidth supportable by the terminal may vary according to the capability of the terminal. Accordingly, the terminal may perform an initial access procedure (eg, an initial connection procedure) by using some of the system bandwidth of the NR system supporting wideband. In order to support access procedures of terminals supporting bandwidths of various sizes, the SS/PBCH block may be multiplexed in the frequency axis within the system bandwidth of the NR system supporting wideband. In this case, the SS/PBCH block may be transmitted as follows.

7 is a conceptual diagram illustrating a second embodiment of a method of transmitting an SS/PBCH block in a communication system.

Referring to FIG. 7 , a wideband component carrier (CC) may include a plurality of bandwidth parts (BWPs). For example, a wideband CC may include 4 BWPs. The base station may transmit SS/PBCH blocks in each of BWP #0 to 3 belonging to the wideband CC. The UE may receive an SS/PBCH block from one or more BWPs of BWP #0 to 3, and may perform an initial access procedure using the received SS/PBCH block.

After detecting the SS/PBCH block, the UE may obtain system information (eg, remaining minimum system information (RMSI)), and may perform a cell access procedure based on the system information. RMSI may be transmitted through PDSCH scheduled by PDCCH. Configuration information of a control resource set (CORESET) through which a PDCCH including scheduling information of a PDSCH through which an RMSI is transmitted may be transmitted through a PBCH in an SS/PBCH block. A plurality of SS/PBCH blocks may be transmitted in the entire system band, and one or more SS/PBCH blocks among the plurality of SS/PBCH blocks may be SS/PBCH blocks associated with RMSI. The remaining SS/PBCH blocks may not be associated with RMSI. The SS/PBCH block associated with RMSI may be defined as a "cell defining SS/PBCH block". The UE may perform a cell search procedure and an initial access procedure using the cell-defined SS/PBCH block. An SS/PBCH block not associated with RMSI may be used for a synchronization procedure and/or a measurement procedure in a corresponding BWP. The BWP through which the SS/PBCH block is transmitted may be limited to one or more BWPs within a wide bandwidth.

RMSI is “Acquisition of configuration information of CORESET from SS/PBCH block (eg, PBCH) → Operation of detecting PDCCH based on configuration information of CORESET → Operation of obtaining scheduling information of PDSCH from PDCCH → Operation of RMSI through PDSCH It can be obtained by performing an operation of receiving ". Transmission resources of the PDCCH may be set by configuration information of CORESET. The RMSI CORESET mapping pattern can be defined as follows. RMSI CORESET may be a CORESET used for transmission and reception of RMSI.

8 is a conceptual diagram for explaining time domain transmission positions of SSBs according to subcarrier spacing and L.

Time domain positions where the SSB is transmitted may be differently defined according to the subcarrier interval and L value. Short UL transmission such as UCI (Uplink Control Information) may be performed on symbol(s) in which SSB is not transmitted within one slot. In SSB transmission with a large subcarrier interval (eg, 120 kHz or 240 kHz SCS), a gap may be set in the middle of consecutive slots including SSBs so that long UL transmission such as URLLC traffic can be performed at least every 1 ms.

As in the example of FIG. 8, a gap for UL transmission is set after 8 slots including SSBs with 120 kHz subcarrier spacing, and after 16 slots including SSBs with 240 kHz subcarrier spacing, for UL transmission A gap can be set.

9A is a conceptual diagram illustrating RMSI CORESET mapping pattern #1 in a communication system, FIG. 9B is a conceptual diagram illustrating RMSI CORESET mapping pattern #2 in a communication system, and FIG. 9C illustrates RMSI CORESET mapping pattern #3 in a communication system. It is a concept diagram.

Referring to FIGS. 9A to 9C , one RMSI CORESET mapping pattern among RMSI CORESET mapping patterns #1-3 may be used, and detailed settings according to one RMSI CORESET mapping pattern may be completed. In the RMSI CORESET mapping pattern #1, the SS/PBCH block, CORESET (eg RMSI CORESET), and PDSCH (eg RMSI PDSCH) may be configured in a TDM manner. RMSI PDSCH may mean a PDSCH through which RMSI is transmitted. In RMSI CORESET mapping pattern #2, CORESET (eg RMSI CORESET) and PDSCH (eg RMSI PDSCH) may be configured in a TDM manner, and PDSCH (eg RMSI PDSCH) is an SS/PBCH block and frequency division multiplexing (FDM). In RMSI CORESET mapping pattern #3, CORESET (eg RMSI CORESET) and PDSCH (eg RMSI PDSCH) may be set in a TDM manner, and CORESET (eg RMSI CORESET) and PDSCH (eg RMSI CORESET) For example, RMSI PDSCH) may be configured in the SS/PBCH block and the FDM scheme.

Only RMSI CORESET mapping pattern #1 can be used in a frequency band of 6 GHz or less. In frequency bands above 6 GHz, RMSI CORESET mapping patterns #1, #2, and #3 may all be used. The numerology of the SS/PBCH block may be different from that of "RMSI CORESET and RMSI PDSCH". Here, the numerology may be a subcarrier spacing. A combination of all numerologies can be used in RMSI CORESET mapping pattern #1. In RMSI CORESET mapping pattern #2, a combination of "SS/PBCH block, RMSI CORESET/PDSCH = 120 kHz, 60 kHz or 240 kHz, 120 kHz" may be used. In RMSI CORESET mapping pattern #3, a combination of "SS/PBCH block, RMSI CORESET/PDSCH = 120 kHz, 120 kHz" may be used.

One RMSI CORESET mapping pattern from among RMSI CORESET mapping patterns #1-3 may be selected according to the combination of the numerology of the SS/PBCH block and the numerology of the RMSI CORESET/PDSCH. The setting information of RMSI CORESET may include table A and table B. Table A shows the number of RBs (resource blocks) of RMSI CORESET, the number of symbols of RMSI CORESET, and the RBs (eg, start RB or end RB) of SS/PBCH blocks and RBs (eg, start RBs) of RMSI CORESET Alternatively, an offset between end RBs may be indicated. Table B may indicate the number of search space sets per slot in each of the RMSI CORESET mapping patterns, an offset of the RMSI CORESET, and an OFDM symbol index. Table B may indicate information for setting a monitoring occasion of the RMSI PDCCH. Each of Table A and Table B may be composed of a plurality of tables. For example, Table A may include Tables 13-1 to 13-8 specified in TS 38.213, and Table B may include Tables 13-9 to 13-13 specified in TS 38.213. The size of each of Table A and Table B may be 4 bits.

In the NR system, PDSCH may be mapped to the time domain according to PDSCH mapping type A or B. PDSCH mapping types A and B may be defined as shown in Table 1 below.

PDSCH
mapping type Normal CP Extended CP S L S+L S L S+L type A {0,1,2,3}
(Note 1) {3,... } {3,... } {0,1,2,3}
(Note 1) {3,... } {3,... } type B {0,… ,12} {2,4,7} {2,… } {0,… ,10} {2,4,6} {2,… } Note 1: S = 3 is applicable only if dmrs-TypeA-Posiition = 3

Type A (ie, PDSCH mapping type A) may be slot-based transmission. When type A is used, the position of the start symbol of the PDSCH may be set to one of {0, 1, 2, 3}. When type A and normal CP are used, the number of symbols constituting the PDSCH (eg, the duration of the PDSCH) may be set to one value from 3 to 14 within a symbol boundary. Type B (ie, PDSCH mapping type B) may be non-slot-based transmission. When type B is used, the position of the start symbol of the PDSCH may be set to one of 0 to 12. When type B and normal CP are used, the number of symbols constituting the PDSCH (eg, the duration of the PDSCH) may be set to one of {2, 4, 7} within a symbol boundary. A DMRS (hereinafter referred to as "PDSCH DMRS") for demodulation of PDSCH (eg, data) may be determined based on a PDSCH mapping type (eg, type A or type B) and an ID indicating a length. ID may be defined differently according to the PDSCH mapping type.

As NR phase 1 standardization is completed in Rel-15 and phase 2 standardization begins in Rel-16, new features are being discussed in the NR system. One of the representative ones is NR-U (Unlicensed). NR-U is a technology to support operation in an unlicensed spectrum used for purposes such as Wi-Fi to increase network capacity by increasing the utilization of limited frequency resources. Assisted Access) technology, and has continued to evolve with Rel-14 LTE-Enhanced LAA (LTE-eLAA) and Rel-15 LTE-Futher Enhanced LAA (FeLAA). In NR, after SI for NR-U, standardization work is in progress through WI in Rel-16.

In the NR-U system, the terminal can determine whether a signal is transmitted from the corresponding base station based on a discovery reference signal (DRS) received from the base station in the same way as in a general NR system. In the NR-U system in Stand-Alone (SA) mode, the UE may obtain synchronization and/or system information based on DRS. In the NR-U system, DRS may be transmitted according to the regulations of the unlicensed band (eg, transmission band, transmission power, transmission time, etc.). For example, according to Occupied Channel Bandwidth (OCB) regulations, a signal may be configured and/or transmitted to occupy 80% of the entire channel bandwidth (eg, 20 MHz).

In the NR-U system, a communication node (eg, a base station or a terminal) may perform Listen Before Talk (LBT) before transmitting signals and/or channels for coexistence with other systems. The signal may be a synchronization signal, a reference signal (eg, DRS, DMRS, channel state information (CSI)-RS, phase tracking (PT)-RS, sounding reference signal (SRS)), and the like. The channel may be a downlink channel, an uplink channel, a sidelink channel, and the like. In embodiments, signal may mean "signal", "channel", or "signal and channel". LBT may be an operation for checking whether a signal is transmitted by another communication node. If it is determined that there is no transmission signal by the LBT (eg, if the LBT is successful), the communication node may transmit a signal in the unlicensed band. If it is determined that the transmission signal exists by the LBT (eg, if the LBT fails), the communication node may not be able to transmit a signal in the unlicensed band. The communication node may perform LBT according to various categories before transmission of a signal. The category of LBT may vary depending on the type of transmission signal.

Another one of the representative features in Rel-16 phase 2 is NR V2X (vehicular to everything). V2X is a technology that supports communication in various scenarios such as between vehicles, vehicles and infrastructure, and vehicles and pedestrians based on LTE D2D (Device to Device) communication. Much discussion has been made in the LTE system, and it is still developing. In NR, discussions on NR V2X are starting with the start of Rel-16.

NR V2X communication (eg, sidelink communication) is performed according to three transmission schemes (eg, unicast scheme, broadcast scheme, groupcast scheme) can When the unicast method is used, a PC5-RRC connection may be established between a first terminal (eg, a transmitting terminal for transmitting data) and a second terminal (eg, a receiving terminal for receiving data), The PC5-RRC connection may mean a logical connection for a pair between a source ID of a first terminal and a destination ID of a second terminal. The first terminal may transmit data (eg, sidelink data) to the second terminal. When a broadcast method is used, the first terminal may transmit data to all terminals. When a groupcast method is used, the first terminal may transmit data to a group (eg, a groupcast group) composed of a plurality of terminals.

When the unicast method is used, the second terminal may transmit feedback information (eg, acknowledgment (ACK) or negative ACK (NACK)) for data received from the first terminal to the first terminal. In the following embodiments, the feedback information may be referred to as "HARQ-ACK", "feedback signal", "physical sidelink feedback channel (PSFCH) signal", and the like. When an ACK is received from the second terminal, the first terminal may determine that data has been successfully received from the second terminal. When a NACK is received from the second terminal, the first terminal may determine that the second terminal has failed to receive data. In this case, the first terminal may transmit additional information to the second terminal based on a hybrid automatic repeat request (HARQ) scheme. Alternatively, the first terminal can improve the probability of receiving data from the second terminal by retransmitting the same data to the second terminal.

When a broadcast method is used, a procedure for transmitting feedback information about data may not be performed. For example, the system information may be transmitted in a broadcast manner, and the terminal may not transmit feedback information on the system information to the base station. Accordingly, the base station may not know whether system information has been successfully received from the terminal. To solve this problem, the base station may periodically broadcast system information.

When a groupcast method is used, a procedure for transmitting feedback information about data may not be performed. For example, necessary information may be periodically transmitted in a group cast method without a transmission procedure of feedback information. However, the target and/or number of terminals participating in communication based on the group cast method is limited, and the data transmitted by the group cast method is data that must be received within a preset time (eg, delay-sensitive data). In this case, a transmission procedure of feedback information may be required even in groupcast sidelink communication. Groupcast sidelink communication may refer to sidelink communication performed in a groupcast manner. When a transmission procedure of feedback information is performed in groupcast sidelink communication, data can be transmitted and received efficiently and stably.

In groupcast sidelink communication, two HARQ-ACK feedback schemes (ie, feedback information transmission procedures) can be supported. If "the number of receiving terminals in the sidelink group is large and service scenario 1 is supported", some receiving terminals belonging to a specific range in the sidelink group may transmit NACK through PSFCH when data reception fails. This method may be "groupcast HARQ-ACK feedback option 1". In service scenario 1, it may be allowed for some receiving terminals belonging to a specific range to receive in a best-effort manner instead of all receiving terminals in a sidelink group. Service scenario 1 may be an extended sensor scenario in which some receiving terminals belonging to a specific range need to receive the same sensor information from a transmitting terminal. In embodiments, a transmitting terminal may refer to a terminal transmitting data, and a receiving terminal may refer to a terminal receiving data.

"If the number of receiving terminals in the sidelink group is limited and service scenario 2 is supported", all receiving terminals belonging to the sidelink group may individually report HARQ-ACK for data through a separate PSFCH. there is. This method may be "groupcast HARQ-ACK feedback option 2". In service scenario 2, since PSFCH resources are sufficient, the transmitting terminal can monitor the HARQ-ACK feedback of all receiving terminals belonging to the sidelink group, and data reception is guaranteed by all receiving terminals belonging to the sidelink group. It can be. Whether or not to apply the ACK/NACK feedback procedure in all transmission schemes can be set statically or semi-fixedly through system information and UE-specific RRC signaling in advance, and can also be set dynamically through control information.

In sidelink communication, ACK/NACK feedback information may be transmitted through PSFCH. The PSFCH may be a channel used by the sidelink receiving terminal to report ACK/NACK information according to whether the PSSCH has been successfully received to the sidelink transmitting terminal. A resource region for PSFCH transmission may be preset in a specific resource pool.

10 is a conceptual diagram for explaining an example of PSFCH configuration within one slot, and FIG. 11 is a conceptual diagram for explaining an example of configuration of PSFCH resources according to a PSFCH transmission period.

Referring to FIG. 11, the terminal can transmit the PSFCH in slot #n+12, which is a slot capable of PSFCH transmission after a previously set sl-MinTimeGapPSFCH (e.g., 3 slots) from the time (slot) at which the PSSCH is received.

For example, the PSFCH may be configured with a period of 1, 2, or 4 logical slots. Referring to FIG. 10, in a slot in which PSFCH transmission is possible, the PSFCH may be repeatedly transmitted over two OFDM symbols. A first symbol among two OFDM symbols through which the PSFCH is transmitted may be used for AGC for adjusting the PSFCH reception power level.

In corresponding symbols, the PSFCH may be transmitted within a frequency resource domain previously set by system information. In this case, the frequency resource region used for PSFCH transmission may be signaled in the form of a bitmap for the corresponding resource pool. The receiving terminal may implicitly select a frequency resource region in which the PSFCH is transmitted based on the slot index and subchannel index of the slot and subchannel in which the PSSCH is received. In addition, among PSFCH resources that can be multiplexed using a cyclic shift of a PSFCH sequence in a resource block (RB) within a corresponding frequency resource region, the index of a PSFCH resource to transmit a PSFCH is determined by a physical layer source ID and Can be selected implicitly based on member ID. In this case, the member ID is used only in groupcast HARQ ACK/NACK feedback option 2 described above, and in other cases, the member ID may be set to 0. The transmission time of the PSFCH may be determined as the first slot capable of transmitting the PSFCH generated after a predetermined predetermined time ( sl-MinTimeGapPSFCH ) from the reception time of the PSSCH. sl-MinTimeGapPSFCH may be set in advance to 2 slots or 3 slots, considering the time to process the received PSSCH and the time to prepare ACK/NACK depending on whether or not the PSSCH is successfully received.

In addition, data reliability in the receiving terminal can be improved by appropriately adjusting the power of the transmitting terminal according to the transmission environment. Interference to other terminals can be mitigated by appropriately adjusting the power of the transmitting terminal. Energy efficiency can be improved by reducing unnecessary transmit power. Power control schemes can be classified into open-loop power control schemes and closed-loop power control schemes. In the open-loop power control scheme, a transmitting terminal may determine transmission power in consideration of settings and measured environments. In the closed-loop power control scheme, a transmitting terminal may determine transmit power based on a transmit power control (TPC) command received from a receiving terminal.

Predicting the received signal strength at the receiving terminal may be difficult due to various causes including multi-path fading channels, interference, and the like. Therefore, the receiving terminal can adjust the received power level (eg, the received power range) by performing an automatic gain control (AGC) operation to prevent quantization errors of the received signal and maintain appropriate received power. In a communication system, a terminal may perform an AGC operation using a reference signal received from a base station. However, in sidelink communication (eg, V2X communication), the reference signal may not be transmitted from the base station. That is, communication between terminals may be performed without a base station in sidelink communication. Therefore, it may be difficult to perform an AGC operation in sidelink communication. In sidelink communication, a transmitting terminal may first transmit a signal (eg, a reference signal) to a receiving terminal before transmitting data, and the receiving terminal performs an AGC operation based on a signal received from the transmitting terminal to range the received power. (eg, received power level) may be adjusted. After that, the transmitting terminal may transmit sidelink data to the receiving terminal. A signal used for the AGC operation may be a duplicated signal for a signal to be transmitted later or a preset signal between terminals.

A time interval required for the AGC operation may be 15 μs. When the subcarrier interval is 15 kHz in the NR system, the time interval (eg, length) of one symbol (eg, OFDM symbol) may be 66.7 μs. When the subcarrier interval is 30 kHz in the NR system, the time interval of one symbol (eg, OFDM symbol) may be 33.3 μs. In the following embodiments, a symbol may mean an OFDM symbol. That is, the time interval of one symbol may be twice or more than the time interval necessary for the AGC operation.

For sidelink communication, transmission of a data channel for data transmission and a control channel including scheduling information for data resource allocation may be required. In sidelink communication, the data channel may be PSSCH (Physical Sidelink Shared CHannel), and the control channel may be PSCCH (Physical Sidelink Control CHannel). Data channels and control channels may be multiplexed in resource domains (eg, time and frequency resource domains).

12 is a conceptual diagram illustrating embodiments of a method of multiplexing a control channel and a data channel in sidelink communication.

Referring to FIG. 12 , sidelink communication may support option 1A, option 1B, option 2, and option 3. When Option 1A and/or Option 1B are supported, the control and data channels may be multiplexed in the time domain. If option 2 is supported, the control channel and data channel can be multiplexed in the frequency domain. If option 3 is supported, the control and data channels can be multiplexed in the time and frequency domains. Sidelink communication may basically support option 3.

In sidelink communication (eg, NR-V2X sidelink communication), a basic unit of resource configuration may be a subchannel. A subchannel can be defined with time and frequency resources. For example, a subchannel may consist of a plurality of symbols (eg, OFDM symbols) in the time domain and may consist of a plurality of resource blocks (RBs) in the frequency domain. A subchannel may be referred to as an RB set. Within a subchannel, data channels and control channels can be multiplexed based on option 3.

In sidelink communication (eg, NR-V2X sidelink communication), transmission resources may be allocated based on mode 1 or mode 2. When mode 1 is used, the base station may allocate sidelink resources for data transmission to the transmitting terminal within a resource pool, and the transmitting terminal receives data using the sidelink resources allocated by the base station. can be transmitted to the terminal. Here, the transmitting terminal may be a terminal transmitting data in sidelink communication, and the receiving terminal may be a terminal receiving data in sidelink communication.

When mode 2 is used, the transmitting terminal can autonomously select a sidelink resource to be used for data transmission by performing a resource sensing operation and/or a resource selection operation within a resource pool. The base station may configure a resource pool for mode 1 and a resource pool for mode 2 in the terminal(s). The resource pool for mode 1 can be set independently of the resource pool for mode 2. Alternatively, a common resource pool may be configured for mode 1 and mode 2.

When mode 1 is used, the base station may schedule resources used for sidelink data transmission to the transmitting terminal, and the transmitting terminal may transmit sidelink data to the receiving terminal using resources scheduled by the base station. Therefore, resource collision between terminals can be prevented. When mode 2 is used, the transmitting terminal can select an arbitrary resource by performing a resource sensing operation and/or a resource selection operation, and can transmit sidelink data using the selected arbitrary resource. Since the above-described procedure is performed based on an individual resource sensing operation and/or resource selection operation of each transmitting terminal, collision between selected resources may occur.

When a UL carrier other than an independent (or dedicated) SL carrier is used in sidelink communication, some of the UL resources may be configured as SL resources and used through SL resource pool configuration. A bitmap of a specific length may be repeatedly applied to slots other than slots in which at least X or more UL symbols are not configured and slots in which S-SSB (Sidelink SSB) is transmitted among slots according to a specific period. That is, only slots indicated as '1' in the bitmap can be used as SL resources. For example, assuming that a 15 kHz SCS is used and X or more UL symbols are set in all slots, there may be 10240 available slots corresponding to one Direct Frame Number (DFN). Assuming that the S-SSB is transmitted in a period of 160ms, when there are two slots used for transmission of the S-SSB within one S-SSB period, the number of slots used for S-SSB transmission among 10240 slots corresponding to the DFN The number is 128. When the bitmap for SL time resource configuration is composed of 10 bits, when the corresponding bitmap is repeatedly applied to the remaining slots except for the 128 slots used for S-SSB transmission among the 10240 slots, additional reserved slots Exclusions may be required. For example, if two reserved slots are additionally excluded, 10110 (= 10240-128-2) slots remain, so a 10-bit bitmap may be repeatedly applied 1011 times to 10110 slots. In this case, assuming that the bitmap is composed of '1111000000', only slots indicated as '1' in the bitmap can be used as SL resources, and finally, a total of 4044 slots corresponding to one DFN are set as SL resources It can be. That is, 4044 slots among 10240 slots corresponding to one DFN can be used for SL communication through SL resource pool configuration.

A sidelink communication system supporting Rel-16 can be designed for terminals (eg, terminals mounted in automobiles, vehicle UEs (V-UEs)) that are not significantly limited in battery capacity. Therefore, the power saving issue may not be greatly considered in the resource sensing/selection operation of the terminal. In a sidelink communication system supporting Rel-17, a terminal with restrictions on battery capacity (e.g., a terminal carried by a pedestrian, a terminal mounted on a bicycle, a terminal mounted on a motorcycle, a P-UE (pedestrian UE)) ), power saving methods will be needed. In the present application, a V-UE may mean a terminal that is not significantly limited in battery capacity, a P-UE may mean a terminal with limitations on battery capacity, and "resource sensing/selection operation" means "resource sensing/selection operation" A sensing operation and/or a resource selection operation" may be included. A resource sensing operation may mean a partial sensing operation or a full sensing operation. The resource selection operation may mean a random selection operation. Also, in the present application, "operation of UE" may be interpreted as "operation of V-UE" and/or "operation of P-UE".

100ms 주기에 따라 부분 센싱 동작을 수행할 수 있다. 기지국은 k의 값을 단말에 알려줄 수 있다. k의 값은 비트맵(bitmap)에 의해 시그널링될 수 있고, 비트맵은 10 비트로 구성될 수 있다. k의 값은 비트맵 내에서 특정 값을 가지는 비트의 위치에 따라 결정될 수 있다. 예를 들어, 비트맵에 포함된 비트들은 "MSB(most significant bit) → LSB(least significant bit)"의 순서로 1 ~ 10에 대응할 수 있다. 예를 들어, 비트맵 내의 첫 번째 비트는 1(즉, k=1)을 지시할 수 있고, 비트맵 내의 두 번째 비트는 2(즉, k=2)를 지시할 수 있고, 비트맵 내의 열 번째 비트는 10(즉, k=10)을 지시할 수 있다. For power saving in LTE V2X, partial sensing operation and / or random selection operation may be introduced. When the partial sensing operation is supported, the terminal may perform the resource sensing operation in a partial interval instead of the entire interval within the sensing window and select a resource based on the result of the partial sensing operation. A partial sensing operation may be used for transmission and reception of periodic data. The terminal may randomly select candidate slots in consideration of a preset minimum number of slots within a resource selection period (eg, resource selection window, sensing window) specified in LTE V2X supporting Rel-14, and select candidate slots k as a criterion

A partial sensing operation may be performed according to a period of 100 ms. The base station may inform the terminal of the value of k. The value of k may be signaled by a bitmap, and the bitmap may consist of 10 bits. The value of k may be determined according to the position of a bit having a specific value in the bitmap. For example, bits included in the bitmap may correspond to 1 to 10 in the order of “most significant bit (MSB) → least significant bit (LSB)”. For example, the first bit in the bitmap can indicate 1 (ie k=1), the second bit in the bitmap can indicate 2 (ie k=2), and the column in the bitmap The th bit may indicate 10 (ie, k=10).

100ms)일 수 있다. 비트맵 내의 두 번째 MSB가 1로 설정된 경우, 부분 센싱 동작의 주기는 200ms(즉, 2

100ms)일 수 있다. 비트맵 내의 LSB가 1로 설정된 경우, 부분 센싱 동작의 주기는 1000ms(즉, 10

100ms)일 수 있다. 단말은 결정된 주기에 따라 부분 센싱 동작을 수행할 수 있다. Rel-14를 지원하는 LTE V2X에서 단말은 100ms 단위의 주기 뿐 아니라 "20ms 단위의 주기 또는 50ms 단위의 주기"에 따라 센싱 동작을 수행할 수 있다. 그러나 P-UE를 위한 자원 풀에서 "20ms 단위의 주기 또는 50ms 단위의 주기"에 따른 부분 센싱 동작은 지원되지 않을 수 있다. The terminal may determine a value corresponding to a bit set to 1 in the bitmap as a value of k, and determine (eg, set) a period of a partial sensing operation based on k. When the MSB in the bitmap is set to 1, the period of partial sensing operation is 100 ms (i.e., 1

100 ms). If the second MSB in the bitmap is set to 1, the period of partial sensing operation is 200 ms (i.e., 2

100 ms). When the LSB in the bitmap is set to 1, the period of partial sensing operation is 1000 ms (i.e., 10

100 ms). The terminal may perform a partial sensing operation according to the determined period. In LTE V2X supporting Rel-14, a terminal may perform a sensing operation according to a period of 100 ms as well as "a period of 20 ms or a period of 50 ms". However, in the resource pool for the P-UE, a partial sensing operation according to "a period of 20 ms or a period of 50 ms" may not be supported.

On the other hand, in the NR communication system, periods of {0, 100ms, 200ms, ..., 1000ms} as well as periods of {1ms, 2ms, ..., 99ms} may be supported. Among the above-described periods for the resource pool, n periods may be selected in advance, and n periods may be set in advance. The maximum value of n may be 16. The base station may transmit information of n periods to the terminal. Information of n periods may be included in resource pool configuration information. Information of n periods may be transmitted using at least one of system information, an RRC message (eg, a common RRC message and/or a UE-specific RRC message), a MAC CE, or control information. In the case of a random selection operation, the terminal may select a resource at random without the above-described sensing operation. In Rel-14 LTE V2X, a resource pool capable of performing the above-described partial sensing operation and/or random sensing operation may be set separately from a resource pool in which a full sensing operation must be performed. For each resource pool, only complete sensing operations can be performed, partial sensing operations can be performed, or both random sensing operations and partial sensing operations can be performed. In the case of a resource pool configured to perform both a random sensing operation and a partial sensing operation, the terminal may implement resource selection by selecting one resource selection method.

Next, methods of transmitting a sidelink positioning signal in sidelink communication will be described. Even when a method (for example, transmission or reception of a signal) performed in a first communication node among communication nodes is described, a second communication node corresponding thereto is described as a method performed in the first communication node and a method (eg, signal transmission or reception) For example, receiving or transmitting a signal) may be performed. That is, when the operation of the transmitting terminal is described, the corresponding receiving terminal may perform an operation corresponding to the operation of the transmitting terminal. Conversely, when the operation of the receiving terminal is described, the corresponding transmitting terminal may perform an operation corresponding to that of the receiving terminal.

3GPP introduced LTE-based positioning technology in Release-9. In Release-9, LTE-based positioning technologies such as ECID (Enhanced Cell Identity) and OTDOA (Observed Time Difference Of Arrival) were introduced, and LTE PRS was newly defined for this. In addition, positioning technologies such as Assisted (A)-GNSS were also introduced in Release-9. In addition, in Release-11, a positioning technology based on UTDOA (Uplink TDOA), which is another form of OTDOA using an uplink signal from a terminal, was introduced.

The NR system introduced functions for supporting NR-based positioning technology from Release-16, and improvements were made to improve the performance of positioning technology from Release-17. However, the corresponding positioning technologies are all Uu link-based positioning technologies between the terminal and the base station, and sidelink-based positioning technologies are not yet supported in the NR system. Sidelink-based V2X services require sidelink-based positioning technology support for collision avoidance or location tracking, and these technologies support not only in-coverage situations but also out-of-coverage situations. ) should also be supported. In addition, sidelink-based positioning technology needs to be supported for sidelink-based public safety services and other services. In order to support sidelink-based positioning technology, transmission of a sidelink positioning reference signal (SL-PRS) for precise positioning may be required. Therefore, the present invention proposes SL-PRS transmission methods for supporting sidelink-based positioning technology.

[Configuring Resources for SL-PRS Transmission]

The SL-PRS for supporting sidelink positioning technology is preferably transmitted in SL slot(s). When a dedicated SL carrier is used, all slots of the SL carrier can be SL slots. However, when a UL carrier other than the dedicated SL carrier is used for sidelink communication, as described above, some of the UL slots of the Uu link are SL. Can be configured as slots. When the SL-PRS is transmitted in a part of the SL slot, fragmentation of the PSCCH and the PSSCH may occur if the SL-PRS is transmitted in the middle part of the slot, so the SL-PRS is preferably transmitted in the latter part of the SL slot do. More specifically, it is preferable that the SL-PRS is transmitted in the last N symbol(s) excluding the guard symbol in the SL slot. In this case, the N symbols may include AGC symbols or may not include AGC symbols.

13A and 13B are conceptual diagrams illustrating cases in which N number of symbol(s) for SL-PRS transmission is configured in an SL slot according to an embodiment of the present invention.

FIG. 13a shows a case where N symbols for SL-PRS transmission are configured including 1 AGC symbol (N=2), and FIG. 13B shows N symbols for SL-PRS transmission including 1 AGC symbol. It shows a case where it is set to include (N = 5). When N symbols in a slot are configured for SL-PRS transmission, N symbols starting from a symbol before the last protection symbol of the corresponding slot may be used for SL-PRS transmission. In the AGC symbol located at the front of the slot, it is preferable to copy and transmit the symbol immediately following the AGC symbol where SL-PRS transmission actually starts.

When N symbols for SL-PRS transmission do not include 1 AGC symbol, FIG. 13a corresponds to the case where 1 symbol is configured for SL-PRS transmission (N=1), and FIG. 13b shows SL- This may correspond to a case where 4 symbols are configured for PRS transmission (N=4). Even when the N symbols for SL-PRS transmission do not include the AGC symbol, the AGC symbol can always be located in front of the symbols for SL-PRS transmission, and in the AGC symbol, the AGC symbol, where SL-PRS transmission actually started, It is preferable to copy and transmit the symbol immediately following the symbol as it is.

Alternatively, similar to S-SSB, a method of setting separate SL slot(s) for SL-PRS transmission and performing only SL-PRS transmission in the corresponding SL slot(s) may be used. When separate slot(s) for SL-PRS transmission is set, in mode 1 in which the base station participates in sidelink resource scheduling, sidelink transmission and reception between terminals occurs in separate slot(s) for SL-PRS transmission It can be implemented and controlled so that it does not. However, in the case of mode 2 in which sidelink transmission and reception are performed based on sensing of the terminal without involvement of the base station, separate slot(s) for SL-PRS transmission are provided in the same way as slots for S-SSB transmission. It is preferable to be excluded from slots for transmitting and receiving sidelink data through configuration. More specifically, slots for SL-PRS transmission may be excluded when a bitmap is applied to slots other than slots for S-SSB transmission in the SL slot configuration. Alternatively, similar to slots for S-SSB transmission, slots for SL-PRS transmission may be excluded before applying the bitmap. Existing sidelink terminals can determine that sidelink transmission and reception does not occur in slots for SL-PRS transmission, and terminals performing SL-PRS transmission and reception receive information on slots for SL-PRS transmission separately. can Therefore, since slots for SL-PRS transmission are separately set in addition to existing resource pool settings, they may not be affected by existing resource pool settings. Alternatively, a separate resource pool for SL-PRS transmission may be configured. Even in this case, the setting of the existing resource pool for performing sidelink transmission and reception is not affected. In this case, symbol(s) for SL-PRS transmission may be set within a slot for SL-PRS transmission similarly to the method described with reference to FIGS. 13A and 13B. In this case, since the symbol (s) for SL-PRS transmission can be set in the remaining symbol (s) except for the last protection symbol of the corresponding slot, the SL-PRS is transmitted through a part of the SL slot excluding the sidelink data transmission symbol. Setting flexibility can be improved compared to the case of transmission.

Even when SL-PRS is transmitted using a separate slot(s) or a separate resource pool, AGC symbol transmission is required. Accordingly, similar to the method described with reference to FIGS. 13A and 13B , N symbols for SL-PRS transmission may or may not include an AGC symbol. Meanwhile, periodicity information and/or offset for SL-PRS transmission may be set in addition to the number of symbol(s) for SL-PRS transmission within an SL slot. The period and/or offset for SL-PRS transmission is preferably set based on SL logical slot(s) in which sidelink transmission/reception actually takes place.

In general, sidelink reference signals (eg, DM-RS, CSI-RS, PT-RS) other than SL-PRS are always transmitted in the same frequency domain as that of PSCCH, PSSCH, or PSBCH. However, in order to improve positioning accuracy performance, it is preferable to transmit the SL-PRS in a wide band. Also, it is preferable that the SL-PRS is not multiplexed with other signals or channels other than the SL-PRS. Therefore, the SL-PRS is preferably transmitted in a separate frequency domain regardless of the frequency domain in which the PSCCH, PSSCH, and PSBCH are transmitted. Therefore, similar to PSFCH, a separate frequency domain for SL-PRS may be configured within a resource pool.

14 is a conceptual diagram illustrating an example in which a separate resource region for SL-PRS transmission is set in an SL resource pool according to an embodiment of the present invention.

Referring to FIG. 14, a resource domain (eg, frequency domain) for SL-PRS transmission may be separately set in all or a part of the SL resource pool. Since the SL-PRS is preferably transmitted as a continuous wideband signal, the resource domain (eg, frequency domain) for SL-PRS transmission is the location (or index) of the starting RB and the resource domain (eg, frequency domain). It can be set to the number (length) of RBs. Alternatively, the resource domain (eg, frequency domain) for SL-PRS transmission is set to the position (or index) of the starting subchannel and the number (length) of subchannels constituting the resource domain (eg, frequency domain) It can be.

If it is necessary for the SL-PRS to be transmitted as a larger wideband signal, the resource region for SL-PRS transmission may be set outside the range of the resource pool. More specifically, as shown in FIG. 15 to be described later, the resource area for SL-PRS transmission is not limited to the SL resource pool for data transmission and reception, and a separate SL resource pool for the resource area for SL-PRS transmission can be set. there is. Alternatively, a resource region for SL-PRS transmission may be configured within the SL BWP based on the SL BWP, apart from the configuration of resource pools. Alternatively, the resource region for SL-PRS transmission may be set to a larger frequency region including or not including SL BWP.

15 is a conceptual diagram illustrating an example in which a resource pool for SL-PRS transmission is set separately from SL resource pools set for sidelink data transmission and reception according to an embodiment of the present invention.

Referring to FIG. 15, a resource region for SL-PRS transmission may be set as a separate frequency resource region not limited to the SL resource pool. This frequency resource region may be set to the location of the starting RB and the number (length) of RBs constituting the resource region, or may be set to the location of the starting subchannel and the number (length) of subchannels.

In order to measure SL-PRS in an area outside the resource pool where data transmission/reception actually occurs, a separate measurement gap may need to be set. When a separate measurement interval is set, measurement of SL-PRS may be performed even in a resource region other than SL-BWP.

Within a set frequency domain, a comb type mapping in which SL-PRS are mapped to each subcarrier at a regular interval may be applied. In this case, a plurality of start positions may be set according to intervals of subcarriers, and when SL-PRS is transmitted in a plurality of symbols, different frequency offset values may be applied to each symbol. Therefore, when the SL-PRS is mapped to N symbols, the SL-PRS can be transmitted at least once in each subcarrier in all frequency domains by changing the location where the SL-PRS is mapped for each symbol. For example, when 4 symbols for SL-PRS transmission (excluding AGC symbols) are set, the interval D between subcarriers to which the SL-PRS sequence is mapped in comb type mapping is set to be less than or equal to N (ie D≤N) may be preferred. For example, if N is set to 4, D is set to 4, and the SL-PRS sequence is mapped by changing the location to which the SL-PRS sequence is mapped for every symbol, the SL-PRS sequence is applied once to each of all subcarriers in the frequency domain. can be mapped. As another example, when N is set to 4 and D is set to 2, the SL-PRS sequence may be mapped twice to each of all subcarriers in the frequency domain.

16 is a conceptual diagram for explaining SL-PRS sequence mapping within a resource region for SL-PRS transmission according to an embodiment of the present invention.

When N symbols for SL-PRS transmission do not include an AGC symbol, the subcarrier interval D may be set to be less than or equal to N, and SL in different subcarriers to which different offsets are applied in units of D symbols -PRS can be transmitted.

Referring to FIG. 16, when N is set to 2, 4, 6, or 12, D is set to 2, and the offset set is set to {0, 1}, an SL-PRS sequence in units of two symbols When mapping, an SL-PRS sequence may be transmitted in all frequency domains over two symbols by applying an offset of 0 and an offset of 1 to the two symbols, respectively. In this case, the position of the subcarrier to which the SL-PRS is initially transmitted may also be selected from D offsets. That is, the position of the subcarrier to which the SL-PRS is initially transmitted may also be set at the value of {0, 1}. 16 illustrates a case in which the position of a subcarrier in which an SL-PRS is initially transmitted is set to 0. In this way, when the starting position is set separately and a different offset is applied to each symbol based on the starting position, SL-PRS mapping patterns that do not overlap with each other can be configured according to the setting of the starting position. Therefore, when different SL-PRS start positions are set for a plurality of terminals, SL-PRS transmission without interference between terminals is possible.

The above-described SL-PRS configuration information (eg, N, transmission period information, frequency domain configuration information, comb type, start position and offset information configuration, etc.) is system information, PC5-RRC signaling, UE-specific ) RRC signaling, a separate protocol for positioning (eg, LTE Positioning Protocol (LPP) or NR Positioning Protocol Annex (NRPPa)), or a combination thereof.

[Transmission method of SL-PRS]

The SL-PRS may be transmitted in a periodic, semi-persistent periodic, or aperiodic manner in association with the periodic information.

In the case of the periodic transmission method, the terminal may periodically transmit the SL-PRS according to the set parameters after a certain time from the time when the SL-PRS configuration information is received (from the base station or other terminal). In the case of the semi-persistent/periodic transmission method, if a separate transmission trigger indicator (activation command) is additionally received (from the base station or other terminal) after the SL-PRS configuration information is received, the terminal determines whether the indicator has been successfully received. whether or not, and periodic SL-PRS transmission can be started. The UE may continue transmitting the SL-PRS until receiving a separate stop indicator (deactivation command). In this case, the indicator may be a 1-bit indicator included in MAC-CE or SCI ( ^1st or ^2nd SCI). Alternatively, a case in which specific field(s) of MAC-CE or SCI indicates a specific state may replace the role of the indicator. Alternatively, the indicator may be transmitted through a separate channel other than MAC-CE or SCI.

In the case of the aperiodic transmission method, similar to the quasi-persistent/periodic transmission method, upon receiving a separate trigger indicator (activation command) (from a base station or other terminal), the terminal may perform SL-PRS transmission. Unlike the quasi-persistent/periodic transmission method, in the case of the aperiodic SL-PRS transmission method, the UE does not transmit the SL-PRS periodically, but once or a predetermined number of times after receiving the trigger indicator Can transmit the SL-PRS there is. Alternatively, information on the number of transmissions may be received together with a trigger indicator. In general, as the number of SL-PRS transmissions increases, the positioning accuracy may increase. Therefore, even in an aperiodic SL-PRS transmission method, it is desirable to continuously and repeatedly transmit the SL-PRS for a certain period of time to increase the positioning accuracy. An indicator for aperiodic SL-PRS transmission may be a 1-bit indicator included in MAC-CE or SCI ( ^1st or ^2nd SCI). Alternatively, a case in which specific field(s) of MAC-CE or SCI indicates a specific state may replace the role of the indicator. Alternatively, the indicator may be transmitted through a separate channel other than MAC-CE or SCI. When information on the number of transmissions is transmitted separately, the corresponding information may also be included in MAC-CE or SCI ( ^1st or ^2nd SCI) and transmitted. Alternatively, the case where specific field(s) of MAC-CE or SCI indicates a specific state may replace the information on the number of transmissions. Alternatively, the information on the number of transmissions may be transmitted through a separate channel other than MAC-CE or SCI. In the case of the semi-persistent/periodic transmission method or the aperiodic transmission method, the trigger indicator and SL-PRS configuration information may be received together (from the base station or other terminal). Alternatively, when a plurality of SL-PRS configuration information is set in advance, an index indicating which SL-PRS configuration information among the plurality of SL-PRS configuration information is to be applied is received along with a trigger indicator (from the base station or other terminal) It can be.

In the case of the quasi-persistent/periodic transmission scheme or the aperiodic SL-PRS transmission scheme, the trigger and stop indicators may be transmitted to the terminal through the base station. Alternatively, when necessary, a specific UE (UE-A) may request SL-PRS transmission and interruption to another UE (UE-B). Such SL-PRS transmission and interruption request functions between terminals may be enabled or disabled by presetting of the base station. In this case, the request message may be transmitted through MAC-CE or SCI ( ^1st or ^2nd SCI) as described above.

When the SL-PRS is transmitted periodically, the transmission period and offset of the SL-PRS may be set as described above. In this case, the transmission period and offset of the SL-PRS may be set in consideration of the transmission period of PSFCH, which is another channel that is periodically set. More specifically, the transmission period of the SL-PRS may be set to coincide with the transmission period of the PSFCH or may be set to be a multiple of the transmission period of the PSFCH. In this case, a slot through which the SL-PRS is transmitted and a slot through which the PSFCH is transmitted may be configured not to overlap each other by applying different offsets to the same or multiple period. Alternatively, a slot through which the SL-PRS is transmitted and a slot through which the PSFCH is transmitted may be set to overlap by applying the same offset to the same or multiple period. In this case, the symbol through which the SL-PRS is transmitted may be set in consideration of the symbol through which the PSFCH is transmitted and the guard symbol in the corresponding slot. For example, referring to the slot structure of FIG. 10, the SL-PRS includes a total of four symbols including the last guard symbol, two symbols for PSFCH (including AGC symbol), and a guard symbol before the PSFCH symbol. It can be mapped from an excluded symbol. In this case, the number of symbols for PSCCH/PSSCH transmission in the corresponding slot is reduced. Alternatively, the SL-PRS may be configured to be transmitted only in the same area as the PSFCH symbol. Since the PSFCH is transmitted over 2 symbols including the AGC symbol, the SL-PRS can also be configured to be transmitted over 2 symbols including the AGC symbol. Since the PSFCH is transmitted through some frequency domains set as bitmaps in the corresponding resource pool, the SL-PRS can be configured to be transmitted in the remaining domains except for the domain in which the PSFCH is transmitted.

[Collision between SL-PRS and PSFCH]

When the SL-PRS is transmitted periodically, as described above, the transmission period and offset of the SL-PRS may be set separately from the PSFCH transmission period and offset, but some of the SL-PRS transmission slots and PSFCH transmission slots Conflicts may occur due to overlapping with each other.

17 is a conceptual diagram illustrating a case in which a collision occurs between a slot in which an SL-PRS is transmitted and a slot in which a PSFCH is transmitted according to an embodiment of the present invention.

Referring to FIG. 17, even if the slot in which the SL-PRS is transmitted and the slot in which the PSFCH is transmitted are the same, the SL-PRS transmission and reception interval (ie, symbol (s)) and the PSFCH transmission and reception interval (ie, symbol ( s)) are different, the UE may individually perform the SL-PRS transmission and reception operation and the PSFCH transmission and reception operation. However, when the SL-PRS transmission/reception period (ie, symbol(s)) and the PSFCH transmission/reception period (ie, symbol(s)) overlap within the same slot, the terminal performs SL-PRS transmission/reception operations and PSFCH All or part of the transmission/reception operation may be performed.

When SL-PRS transmission and PSFCH transmission overlap, a UE capable of simultaneously performing SL-PRS transmission and PSFCH transmission may simultaneously perform SL-PRS transmission and PSFCH transmission. However, a UE that cannot simultaneously perform SL-PRS transmission and PSFCH transmission may perform SL-PRS transmission or PSFCH transmission by selecting one of SL-PRS transmission and PSFCH transmission. In this case, when the priority of the SL-PRS is set separately, the UE compares the priority of the SL-PRS and the priority of the PSFCH, and when the priority of the SL-PRS is higher than the priority of the PSFCH, the priority of the SL-PRS transmission can be performed. Meanwhile, when the priority of the SL-PRS is lower than the priority of the PSFCH, the UE may drop transmission of the SL-PRS and transmit the PSFCH. If the priority of the SL-PRS is not separately set, the UE may drop the transmission of the SL-PRS and transmit the PSFCH, assuming that the PSFCH always has a higher priority than the SL-PRS. Alternatively, the UE may forgo transmission of the PSFCH and transmit the SL-PRS, assuming that the PSFCH always has a lower priority than the SL-PRS.

When SL-PRS reception and PSFCH reception overlap, a UE capable of simultaneous SL-PRS reception and PSFCH reception can simultaneously perform SL-PRS reception and PSFCH reception. A UE that cannot simultaneously perform SL-PRS reception and PSFCH reception may perform SL-PRS reception or PSFCH reception by selecting one of SL-PRS reception and PSFCH reception. In this case, when the priority of the SL-PRS is set separately, the UE compares the priority of the SL-PRS and the priority of the PSFCH, and when the priority of the SL-PRS is higher than the priority of the PSFCH, the priority of the SL-PRS reception can be performed. Meanwhile, if the priority of the SL-PRS is lower than the priority of the PSFCH, the UE may drop the reception of the SL-PRS and perform the reception of the PSFCH. If the priority of the SL-PRS is not set separately , Similar to the above-described transmission procedure, the UE may always give up SL-PRS reception or conversely always perform only SL-PRS reception regardless of the priority of the PSFCH.

When SL-PRS transmission (or reception) and PSFCH reception (or transmission) overlap, the terminal cannot perform transmission and reception operations at the same time, so the terminal performs SL-PRS transmission (or reception) or PSFCH reception (or transmission) can be done In this case, when the priority of the SL-PRS is set separately, the UE compares the priority of the SL-PRS and the priority of the PSFCH, and when the priority of the SL-PRS is higher than the priority of the PSFCH, the UE selects the SL-PRS. If transmission (or reception) is performed and the priority of the SL-PRS is lower than the priority of the PSFCH, the SL-PRS transmission (or reception) may be abandoned and the PSFCH transmission (or reception) may be performed. Similar to the above-described procedures, if the priority of SL-PRS is not separately set, the UE always gives up SL-PRS transmission (or reception) regardless of PSFCH priority, or conversely always transmits (or receives) SL-PRS can be performed.

When LTE and NR PSCCH / PSSCH transmission and reception and UL transmission and transmission (or reception) of SL-PRS overlap, if the priority of SL-PRS is set separately, the UE transmits and receives LTE and NR PSCCH / PSSCH priority and UL A transmission or reception operation may be performed according to the determined final priority by comparing the priority of transmission with the priority of transmission (or reception) of the SL-PRS and determining the final priority. If the priority of the SL-PRS is not separately set, the UE may give up transmitting (or receiving) the SL-PRS or conversely always transmit (or receive) the SL-PRS.

[Report of SL-PRS measurement results]

The terminal receiving the SL-PRS needs to report the measurement result of the SL-PRS to the base station, LMF (Location Management Function) or other terminals. In this case, reporting to the base station or LMF can be performed through the existing uplink and existing LPP protocols, and reporting to other terminals can be performed through the sidelink and MAC-CE. The type of measurement result reported by the terminal for positioning may vary depending on the positioning method.

For example, in the case of the OTDOA method, overall information on the measured PRS (eg, physical cell ID, global cell ID, PRS ID, PRS resource ID, PRS resource set ID, frequency location (ARFCN) etc.), information on the time at which the measurement was made (eg index of a specific slot), relative timing information from a specific reference, quality information of timing information, and RSRP measurement information, etc. will be reported. can Depending on the setting, additional information on a path may also be reported. In the case of the Multi-RTT (Round Trip Time) method, unlike the OTDOA method, an RX-TX time difference may be reported instead of relative timing information. In the case of an angle-based positioning method, reception beam information or the like capable of inferring a reception angle may be reported instead of timing information.

When a timing-based positioning scheme such as TDOA and RTT or an angle-based positioning scheme such as AOA and AOD is used for sidelink positioning, a positioning process may be performed by reporting the same or similar measurement result as the existing one. However, a procedure for measuring and reporting a measurement result considering the positioning environment of a side link different from the existing Uu link may be required.

In the case of a timing-based positioning method such as the OTDOA method, it may be necessary to report relative timing information from a specific reference time. In this case, in the conventional method, a method of defining a reference cell and measuring and reporting relative timing information based on a PRS reception point in the corresponding cell may be used. However, in sidelink positioning, a reference may be set to a specific terminal (reference terminal) rather than a specific cell. In this case, information on the reference terminal may be a terminal ID (eg, TX ID), and the corresponding information may be included in assistant information for positioning and delivered to other terminals performing positioning. In addition to the ID of the reference terminal as positioning auxiliary information, information about the time at which the PRS from the corresponding terminal is expected to be received (eg, nr-SL-PRS-ExpectedRSTD ) and +/- offset information (eg, nr -DL-PRS-ExpectedRSTD-Uncerainty ) may be used. In this case, other terminals performing sidelink positioning can reduce positioning complexity by setting reception timing from the reference terminal that can be predicted to some extent.

In addition, in the case of a positioning method based on a carrier phase, which is being discussed to be newly introduced in sidelink and Uu link positioning, a measurement result report different from the existing one is required. For example, relative phase difference information from a specific criterion such as reference signal phase difference (RSPD) and quality for corresponding measurement values such as phaseQualityValue and phaseQualityResolution Reporting of information may be required. More specifically, in the case of RSPD, the resolution step for the phase difference value may be set differently according to various positioning situations, and may be set in advance through an LMF or a terminal requesting measurement. In addition, the phase quality value (phaseQualityValue) is an estimated value for the uncertainty of the phase difference value and can be expressed as a degree, and the phase quality resolution (phaseQualityResolution) is a value representing the resolution to which the phase quality value (phaseQualityValue) is applied, and various values (eg, 0.01, 0.1, 1, 10, or 20 degrees). Just as the measurement results for the timing or angle-based positioning method can be applied without a significant difference between Uu link positioning and sidelink positioning, the above-described measurement results for the carrier phase-based positioning method are the carrier phase-based positioning method. When applied to Uu link positioning and sidelink positioning, there is no significant difference between Uu link positioning and sidelink positioning.

The above-described SL-PRS transmission and reception related settings, measurement and reporting procedure related settings, etc. for precise positioning are set by the base station, LMF, or base station and LMF to which the terminals performing the positioning belong (Scheme 1), or It can be set by any terminal among the terminals that perform or any other terminal other than the corresponding terminals (Scheme 2).

In this case, as a method of indicating whether to operate based on Scheme 1 or Scheme 2, Scheme 1 or Scheme 2 is implicitly set according to whether a group of terminals performing positioning exists within network coverage. Scheme 1 or Scheme 2 is explicitly specified by a method (e.g., Scheme 1 in case of in-coverage state, Scheme 2 in case of out-of-coverage state) or base station setting A method set to may be used. Alternatively, a method of operating in Scheme 2 in the out-of-coverage state and operating in Scheme 1 or Scheme 2 according to the setting of the base station in the in-coverage state can also be applied.

Synchronization between terminals is very important in performing precise positioning. In particular, in the case of timing-based positioning methods, synchronization between terminals must be ensured so that transmission/reception and measurement of the SL-PRS are performed accurately to obtain high positioning accuracy. Therefore, a clear setting of standards for inter-device synchronization must be made. In the case of Scheme 1, the criterion for synchronization between terminals may be a corresponding base station. Alternatively, GNSS or a specific terminal (eg, reference UE) may be set as a reference for synchronization between terminals by the base station. In this case, the base station transmitting the configuration information of Scheme 1 may include information on whether the synchronization criterion is the base station, GNSS, or a specific terminal (eg, reference UE) in the configuration information. When a specific UE (eg, reference UE) is a criterion for synchronization between UEs, information on the specific UE (eg, TX ID or UE ID) may be additionally included in the configuration information. When a base station serves as a reference for synchronization between terminals, when a reference base station (eg, reference gNB) is different from a base station transmitting configuration information, information on the corresponding base station (eg, Cell ID) is added to the configuration information can be included If the base station serving as the basis for synchronization between terminals and the base station transmitting configuration information are the same, since the terminals performing positioning already know the information of the corresponding base station, the information on the base station serving as the basis for synchronization between terminals is included in the configuration information. need not be included additionally. In the case of Scheme 2, information about whether any terminal transmitting configuration information of Scheme 2, another specific terminal (eg, reference UE), a specific base station (eg, reference gNB), or GNSS is a criterion for synchronization between terminals It can be included in configuration information. When a specific terminal (eg, reference UE) or a specific base station (eg, reference gNB) is set as a criterion for synchronization between terminals, information on a specific terminal or a specific base station (eg, TX ID, terminal ID or Cell ID) Additionally, it may be included in setting information.

The operation of the method according to the embodiment of the present invention can be implemented as a computer readable program or code on a computer readable recording medium. A computer-readable recording medium includes all types of recording devices in which information that can be read by a computer system is stored. In addition, computer-readable recording media may be distributed to computer systems connected through a network to store and execute computer-readable programs or codes in a distributed manner.

In addition, the computer-readable recording medium may include hardware devices specially configured to store and execute program commands, such as ROM, RAM, and flash memory. The program instructions may include high-level language codes that can be executed by a computer using an interpreter as well as machine language codes such as those produced by a compiler.

Although some aspects of the invention have been described in the context of an apparatus, it can also refer to a description according to a corresponding method, where a block or apparatus corresponds to a method step or a feature of a method step. Similarly, aspects described in the context of a method may also be represented by a corresponding block or item or a corresponding feature of a device. Some or all of the method steps may be performed by (or using) a hardware device, such as, for example, a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, at least one or more of the most important method steps may be performed by such an apparatus.

In embodiments, a programmable logic device (eg, a field programmable gate array) may be used to perform some or all of the functions of the methods described herein. In embodiments, a field-programmable gate array may operate in conjunction with a microprocessor to perform one of the methods described herein. Generally, the methods are preferably performed by some hardware device.

Although the above has been described with reference to the preferred embodiments of the present invention, those skilled in the art can variously modify and change the present invention without departing from the spirit and scope of the present invention described in the claims below. You will understand that you can.

Claims (20)

A method of transmitting a sidelink positioning reference signal (SL-PRS) performed by a first terminal,
Receiving configuration information for transmission of SL-PRS; and
Transmitting the SL-PRS based on the setting information;
The configuration information includes information indicating sidelink (SL) slot(s) through which the SL-PRS is transmitted and symbols in the SL slot(s),
SL-PRS transmission method. The method of claim 1,
The SL slot(s) through which the SL-PRS is transmitted are set regardless of a resource pool for transmitting and receiving sidelink data or set in a separate resource pool for transmitting the SL-PRS.
SL-PRS transmission method. The method of claim 1,
In the first slot among the SL slot(s) in which the SL-PRS is transmitted, the SL-PRS is transmitted in the last N (N is a natural number equal to or greater than 1) symbol(s) excluding the last guard symbol of the first slot. transmitted, and the N symbol(s) may or may not include an automatic gain control (AGC) symbol,
SL-PRS transmission method. The method of claim 1,
The SL-PRS is transmitted in a first frequency domain other than the frequency domain in which a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSSCH), and a physical sidelink broadcast channel (PSBCH) are transmitted.
SL-PRS transmission method. The method of claim 4,
The first frequency domain is indicated by an index indicating a starting resource block (RB) or starting subchannel and the number of consecutive RBs or subchannels,
SL-PRS transmission method. The method of claim 4,
In the first frequency domain, the SL-PRS is mapped in a comb form according to the interval of D (D is a natural number of 2 or more) subcarriers, and the SL-PRS is transmitted in a plurality of symbols. In this case, the SL-PRS is transmitted with a different frequency offset value applied to each symbol of the plurality of symbols.
SL-PRS transmission method. The method of claim 1,
The configuration information is received from a first base station to which the first terminal is connected, a location management function (LMF), or a second terminal belonging to a group of terminals performing sidelink positioning with the first terminal,
SL-PRS transmission method. The method of claim 7,
From which communication node among the first base station, the LMF, and the second terminal the configuration information is received, the first terminal is in an in-coverage state or an out-of-coverage state. coverage) state and / or determined by the configuration of the first base station,
SL-PRS transmission method. The method of claim 7,
The SL-PRS is transmitted in a periodic transmission method, a semi-persistent / periodic transmission method, or an aperiodic transmission method,
SL-PRS transmission method. The method of claim 9,
When a trigger indicator is received from the first base station or the second terminal, the SL-PRS is repeatedly transmitted a predetermined number of times in an aperiodic transmission scheme, and the predetermined number of times is included in a preset value and the configuration information A signaled value, or a value signaled by a medium access control-control element (MAC-CE) or sidelink control information (SCI),
SL-PRS transmission method. The method of claim 9,
The configuration information further includes information on a periodicity and/or offset of the SL-PRS transmission, and when the SL-PRS is transmitted in the periodic transmission method, the SL-PRS transmission The period is set to match the period of PSFCH (physical sidelink feedback channel) transmission or to be a multiple of the PSFCH transmission period.
SL-PRS transmission method. The method of claim 11,
Different offsets are applied to the slot in which the SL-PRS is transmitted and the slot in which the PSFCH is transmitted, or the same offset is applied to the slot in which the SL-PRS is transmitted and the slot in which the PSFCH is transmitted,
SL-PRS transmission method. As an operating method of a communication node for setting transmission of a sidelink positioning reference signal (SL-PRS),
Transmitting configuration information for transmission of SL-PRS to a first terminal; and
Receiving a measurement result of the SL-PRS transmitted by the first terminal based on the configuration information from a group of terminals performing sidelink positioning with the first terminal;
The configuration information includes information indicating sidelink (SL) slot(s) through which the SL-PRS is transmitted and symbols in the SL slot(s),
How to set up SL-PRS transmission. The method of claim 13,
The SL slot(s) through which the SL-PRS is transmitted are set regardless of a resource pool for transmitting and receiving sidelink data or set in a separate resource pool for transmitting the SL-PRS.
How to set up SL-PRS transmission. The method of claim 13,
The SL-PRS is transmitted in a first frequency domain other than the frequency domain in which a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSSCH), and a physical sidelink broadcast channel (PSBCH) are transmitted.
How to set up SL-PRS transmission. The method of claim 15
In the first frequency domain, the SL-PRS is mapped in a comb form according to the interval of D (D is a natural number of 2 or more) subcarriers, and the SL-PRS is transmitted in a plurality of symbols. In this case, the SL-PRS is transmitted with a different frequency offset value applied to each symbol of the plurality of symbols.
How to set up SL-PRS transmission. The method of claim 13,
The communication node is a first base station to which the first terminal is connected, a location management function (LMF), or a second terminal belonging to a group of terminals performing sidelink positioning with the first terminal,
How to set up SL-PRS transmission. As a first terminal performing sidelink positioning reference signal (SL-PRS) transmission,
processor; and
A transceiver controlled by the processor;
The processor:
receiving configuration information for transmission of the SL-PRS through the transceiver; and
It is set to perform the step of transmitting the SL-PRS through the transceiver based on the setting information;
The configuration information includes information indicating sidelink (SL) slot(s) through which the SL-PRS is transmitted and symbols in the SL slot(s),
Terminal 1. The method of claim 18
The SL slot(s) through which the SL-PRS is transmitted are set regardless of a resource pool for transmitting and receiving sidelink data or set in a separate resource pool for transmitting the SL-PRS.
Terminal 1. The method of claim 18
The SL-PRS is transmitted in a first frequency domain other than a frequency domain in which a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSSCH), and a physical sidelink broadcast channel (PSBCH) are transmitted, and within the first frequency domain In , the SL-PRS is mapped in a comb form according to the interval of D (D is a natural number of 2 or more) subcarriers, and when the SL-PRS is transmitted in a plurality of symbols, the SL-PRS is transmitted with a different frequency offset value applied to each symbol of the plurality of symbols,
Terminal 1.

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