KR20230152571A - Method and apparatus for coexistence between long term evolution sidelink and new radio sidelink - Google Patents

Abstract

A method and apparatus for coexistence between an LTE sidelink and an NR sidelink are disclosed. A method of a first terminal supporting a first RAT and a second RAT includes determining candidate resources by performing a resource sensing operation based on the first RAT, and determining candidate resources for the candidate resources in consideration of second RAT resource information. 1. It includes performing a RAT-based resource selection operation, and performing SL communication based on the first RAT with a second terminal using the resources selected by the resource selection operation.

Description

Coexistence method and device between LTE sidelink and NR sidelink {METHOD AND APPARATUS FOR COEXISTENCE BETWEEN LONG TERM EVOLUTION SIDELINK AND NEW RADIO SIDELINK}

This disclosure relates to sidelink communication technology, and more specifically, to technology for coexistence between long term evolution (LTE) sidelink (SL) and new radio (NR) SL on the same channel.

In order to process rapidly increasing amounts of wireless data, a frequency band (e.g., 6 GHz) higher than the frequency band (e.g., a frequency band of 6 GHz or less) of the long term evolution (LTE) communication system (or LTE-A communication system) A communication system (for example, a new radio (NR) communication system) using the above frequency bands is being considered. The NR communication system can support not only frequency bands above 6 GHz but also frequency bands below 6 GHz, and can support a variety of communication services and scenarios compared to the LTE communication system. Additionally, the requirements of the NR communication system may include enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communication (URLLC), and massive Machine Type Communication (mMTC).

Meanwhile, the LTE communication system and the NR communication system can support sidelink communication. LTE SL (sidelink) communication and NR SL communication can be performed on the same resource. In this case, a collision between LTE SL communication and NR SL communication may occur. Technologies for coexistence between LTE SL communication and NR SL communication on the same resource (e.g., same channel) are needed.

The purpose of the present disclosure to solve the above problems is to provide a method and device for coexistence between long term evolution (LTE) sidelink (SL) communication and new radio (NR) SL communication.

A method of a first terminal supporting a first RAT and a second RAT according to the first embodiment of the present disclosure to achieve the above object, comprising: determining candidate resources by performing a resource sensing operation based on the first RAT; Performing a first RAT-based resource selection operation for the candidate resources in consideration of second RAT resource information, and SL communication based on the first RAT with the second terminal using the resources selected by the resource selection operation. It includes steps to perform.

When resource sharing between the first RAT and the second RAT is established, the second RAT resource information may be shared in the first RAT-based resource selection operation, and the first RAT may be NR communication technology, The second RAT may be LTE communication technology.

The second RAT resource information may indicate one or more resources reserved by a third terminal supporting the second RAT, and one or more resources reserved among the candidate resources in the first RAT-based resource selection operation. At least one candidate resource that overlaps with the resources may be excluded.

"If the second RAT resource information indicates one or more resources reserved by a third terminal supporting the second RAT, and the RSRP of at least one reserved resource among the one or more reserved resources is equal to or greater than the RSRP threshold ", In the first RAT-based resource selection operation, at least one candidate resource that overlaps the at least one reserved resource among the candidate resources may be excluded.

The second RAT resource information includes time resource information reserved by the third terminal, frequency resource information reserved by the third terminal, period information of the resource reserved by the third terminal, and RSRP for the reserved resource. It may include at least one of information or priority information about data of the third terminal.

The RSRP threshold can be set by system information, PC5-RRC signaling, or UE-RRC signaling.

If the first SCS applied to the first RAT and the second SCS applied to the second RAT are different, the selected resources may include all slots overlapping with the duration corresponding to the second RAT-based SL transmission, , the first RAT-based SL communication can be performed continuously during all of the slots.

If the first SCS applied to the first RAT and the second SCS applied to the second RAT are different, the selected resources may include a first slot overlapping the duration corresponding to SL transmission based on the second RAT. And, the first RAT-based SL communication may be allowed in the first slot.

In the first RAT-based SL communication between the first terminal and the second terminal, when the first RAT-based PSFCH transmission overlaps with the second RAT-based SL transmission, the first RAT-based PSFCH transmission is dropped or It can be disabled.

The step of performing the first RAT-based resource selection operation includes, when the first RAT-based PSFCH transmission overlaps with the second RAT-based SL transmission, the first RAT-based PSFCH transmission among the candidate resources. It may include excluding at least one candidate resource for associated PSSCH transmission.

A first terminal supporting the first RAT and the second RAT according to the second embodiment of the present disclosure to achieve the above purpose includes a processor, wherein the first terminal performs resource sensing based on the first RAT. Determine candidate resources by performing an operation, perform a first RAT-based resource selection operation on the candidate resources by considering second RAT resource information, and perform a second RAT-based resource selection operation using the resources selected by the resource selection operation. Causes the terminal to perform SL communication based on the first RAT.

When resource sharing between the first RAT and the second RAT is established, the second RAT resource information may be shared in the first RAT-based resource selection operation, and the first RAT may be NR communication technology, The second RAT may be LTE communication technology.

The second RAT resource information may indicate one or more resources reserved by a third terminal supporting the second RAT, and one or more resources reserved among the candidate resources in the first RAT-based resource selection operation. At least one candidate resource that overlaps with the resources may be excluded.

"If the second RAT resource information indicates one or more resources reserved by a third terminal supporting the second RAT, and the RSRP of at least one reserved resource among the one or more reserved resources is equal to or greater than the RSRP threshold ", In the first RAT-based resource selection operation, at least one candidate resource that overlaps the at least one reserved resource among the candidate resources may be excluded.

The second RAT resource information includes time resource information reserved by the third terminal, frequency resource information reserved by the third terminal, period information of the resource reserved by the third terminal, and RSRP for the reserved resource. It may include at least one of information or priority information about data of the third terminal.

The RSRP threshold can be set by system information, PC5-RRC signaling, or UE-RRC signaling.

If the first SCS applied to the first RAT and the second SCS applied to the second RAT are different, the selected resources may include all slots overlapping with the duration corresponding to the second RAT-based SL transmission, , the first RAT-based SL communication can be performed continuously during all of the slots.

If the first SCS applied to the first RAT and the second SCS applied to the second RAT are different, the selected resources may include a first slot overlapping the duration corresponding to SL transmission based on the second RAT. And, the first RAT-based SL communication may be allowed in the first slot.

In the first RAT-based SL communication between the first terminal and the second terminal, when the first RAT-based PSFCH transmission overlaps with the second RAT-based SL transmission, the first RAT-based PSFCH transmission is dropped or It can be disabled.

When performing the first RAT-based resource selection operation, the processor determines that the first terminal, when PSFCH transmission based on the first RAT overlaps with SL transmission based on the second RAT, selects the candidate resource among the candidate resources. This may cause at least one candidate resource for PSSCH transmission associated with the first RAT-based PSFCH transmission to be excluded.

According to the present disclosure, the terminal can determine candidate resources by performing a new radio (NR) sidelink (SL) resource sensing operation, and perform an NR SL resource selection operation for candidate resources by considering long term evolution (LTE) resource information. can be performed. According to the above operation, when NR SL communication and LTE SR communication coexist in the same channel, NR SL communication can be performed on resources selected in consideration of LTE resource information. Therefore, collisions between NR SL communication and LTE SL communication can be prevented, the efficiency of resource use can be improved, and the performance of the communication system can be improved.

1 is a conceptual diagram showing a first embodiment of a communication system.
Figure 2 is a block diagram showing a first embodiment of a communication node constituting a communication system.
Figure 3 is a conceptual diagram showing a first embodiment of a type 1 frame structure.
Figure 4 is a conceptual diagram showing a first embodiment of a type 2 frame structure.
Figure 5 is a conceptual diagram showing a first embodiment of a method for transmitting SS/PBCH blocks in a communication system.
Figure 6 is a conceptual diagram showing a first embodiment of an SS/PBCH block in a communication system.
Figure 7 is a conceptual diagram showing a second embodiment of a method for transmitting SS/PBCH blocks in a communication system.
Figure 8 is a conceptual diagram showing a first embodiment of SSB burst setting.
Figure 9a is a conceptual diagram showing RMSI CORESET mapping pattern #1 in a communication system.
Figure 9b is a conceptual diagram showing RMSI CORESET mapping pattern #2 in a communication system.
Figure 9c is a conceptual diagram showing RMSI CORESET mapping pattern #3 in a communication system.
Figure 10 is a conceptual diagram showing a first embodiment of slot configuration in which PSFCH is configured.
Figure 11 is a conceptual diagram showing a first embodiment of PSFCH for ACK/NACK transmission.
FIG. 12 is a conceptual diagram illustrating embodiments of a method for multiplexing a control channel and a data channel in sidelink communication.
Figure 13 is a conceptual diagram showing a first embodiment of a resource selection operation.
Figure 14 is a conceptual diagram showing a first embodiment of a resource re-selection operation.
Figure 15a is a conceptual diagram showing a first embodiment of a method for configuring PSCCH resources and PSSCH resources adjacent to each other.
Figure 15b is a conceptual diagram showing a first embodiment of a method for configuring PSCCH resources and PSSCH resources to be non-adjacent.
Figure 16 is a conceptual diagram showing an example in which resource grids between LTE SL and NR SL are not aligned.
Figure 17 is a conceptual diagram showing a first embodiment of NR transmission using different transmission powers.
Figure 18a is a first embodiment showing PSFCH resource allocation.
Figure 18b is a second embodiment showing PSFCH resource allocation.
Figure 19 is a conceptual diagram showing a first embodiment of a timeline for transmitting LTE sensing information to the NR SL module.

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

Terms such as first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, a first component may be referred to as a second component, and similarly, the second component may be referred to as a first component without departing from the scope of the present disclosure. The term “and/or” includes any of a plurality of related stated items or a combination of a plurality of related stated items.

In embodiments of the present disclosure, “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.” Additionally, in embodiments of the present disclosure, “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.”

When a component is said to be "connected" or "connected" to another component, it is understood that it may be directly connected to or connected to the other component, but that other components may exist in between. It should be. On the other hand, when it is mentioned that a component is “directly connected” or “directly connected” to another component, it should be understood that there are no other components in between.

The terms used in this disclosure are only used to describe specific embodiments and are not intended to limit the disclosure. Singular expressions include plural expressions unless the context clearly dictates otherwise. In the present disclosure, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the technical field to which this disclosure pertains. 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 technology, and unless clearly defined in the present disclosure, should not be interpreted in an idealized or excessively formal sense. No.

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

A communication system to which embodiments according to the present disclosure are applied will be described. The communication system may be a 4G communication system (e.g., long-term evolution (LTE) communication system, LTE-A communication system), a 5G communication system (e.g., new radio (NR) communication system), a 6G communication system, etc. there is. The 4G communication system can support communication in frequency bands below 6GHz, and the 5G communication system can support communication in frequency bands above 6GHz as well as frequency bands below 6GHz. Communication systems to which embodiments according to the present disclosure are applied are not limited to those described below, and embodiments according to the present disclosure can be applied to various communication systems. Here, communication system may be used in the same sense as communication network, “LTE” may indicate “4G communication system”, “LTE communication system” or “LTE-A communication system”, and “NR” may refer to may indicate “5G communication system” or “NR communication system”.

In an embodiment, “setting an operation (e.g., a transmission operation)” means “setting information (e.g., information element, parameter) for the operation” and/or “performing the operation.” This may mean that “indicating information” is signaled. “An information element (eg, parameter) is set” may mean that the information element is signaled. Signaling includes system information (SI) signaling (e.g., transmission of system information block (SIB) and/or master information block (MIB)), RRC signaling (e.g., transmission of RRC parameters and/or upper layer parameters) , MAC control element (CE) signaling, or PHY signaling (e.g., transmission of downlink control information (DCI), uplink control information (UCI), and/or sidelink control information (SCI)).

In the present disclosure, even when a method performed in a first communication node among communication nodes (e.g., transmission or reception of a signal) is described, the corresponding second communication node is similar to the method performed in the first communication node. A method (eg, receiving or transmitting a signal) may be performed. For example, when the operation of a terminal is described, the base station corresponding to the terminal may perform an operation corresponding to the operation of the terminal. Conversely, when the operation of the base station is described, a terminal corresponding to the base station can perform an operation corresponding to the operation of the base station. Additionally, when the operation of the first terminal is described, the second terminal corresponding to the first terminal may perform an operation corresponding to the operation of the first terminal. Conversely, when the operation of the second terminal is described, the first terminal corresponding to the second terminal may perform an operation corresponding to the operation of the second terminal.

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

Referring to FIG. 1, the 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 (e.g., serving-gateway (S-GW), packet data network (PDN)-gateway (P-GW), mobility management entity (MME)). More may be included. If the communication system 100 is a 5G communication system (e.g., 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), etc. may include.

A plurality of communication nodes 110 to 130 may support communication protocols (eg, LTE communication protocol, LTE-A communication protocol, NR communication protocol, etc.) specified in the 3rd generation partnership project (3GPP) standard. The plurality of communication nodes 110 to 130 may use code division multiple access (CDMA) technology, wideband CDMA (WCDMA) technology, time division multiple access (TDMA) technology, frequency division multiple access (FDMA) technology, orthogonal frequency division (OFDM) technology. 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.

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

Referring to FIG. 2, the communication node 200 may include at least one processor 210, a memory 220, and a transmitting and receiving device 230 that is connected to a network and performs communication. Additionally, the communication node 200 may further include an input interface device 240, an output interface device 250, a storage device 260, etc. Each component included in the communication node 200 is connected by a bus 270 and can communicate with each other.

However, each component included in the communication node 200 may be connected through an individual interface or individual bus centered on the processor 210, rather than 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 disclosure are performed. Each of the memory 220 and the storage device 260 may be comprised of at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 220 may be comprised of at least one of read only memory (ROM) and random access memory (RAM).

Referring again to FIG. 1, the communication system 100 includes a plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) and 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 NB (NodeB), eNB (evolved NodeB), gNB, ABS (advanced base station), and HR. -High reliability-base station (BS), base transceiver station (BTS), 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), radio remote head (RRH), transmission point (TP), transmission and reception point (TRP), etc.

Each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 includes a user equipment (UE), a terminal equipment (TE), an 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), etc.

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. , 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, 120-2) transmits the signal received from the core network to the corresponding terminal (130-1, 130-2, 130-3, 130). -4, 130-5, 130-6), and the signal received from the corresponding terminal (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) is sent to the core network. can be transmitted to.

In addition, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 performs MIMO transmission (e.g., single user (SU)-MIMO, multi user (MU)- MIMO, massive MIMO, etc.), coordinated multipoint (CoMP) transmission, carrier aggregation (CA) transmission, transmission in an unlicensed band, device to device communication (D2D) (or , ProSe (proximity services), IoT (Internet of Things) communication, dual connectivity (DC), etc. Here, each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 is connected to a base station 110-1, 110-2, 110-3, and 120-1. , 120-2) and operations corresponding to those supported by the base stations 110-1, 110-2, 110-3, 120-1, and 120-2. For example, the second base station 110-2 may transmit a signal to the fourth terminal 130-4 based on the SU-MIMO method, and the fourth terminal 130-4 may transmit a signal to the fourth terminal 130-4 based on the SU-MIMO method. A signal can 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 method, and the fourth terminal 130-4 and the fifth terminal 130-5 can each 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 method, and the fourth terminal 130-4 may transmit a signal to the fourth terminal 130-4. The terminal 130-4 can receive signals from the first base station 110-1, the second base station 110-2, and the third base station 110-3 using the CoMP method. Each of a plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) has a terminal (130-1, 130-2, 130-3, 130-4) within its cell coverage. , 130-5, 130-6), and signals can be transmitted and received based on the CA method. The first base station 110-1, the second base station 110-2, and the third base station 110-3 each control 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 can perform D2D under the control of each of the second base station 110-2 and the third base station 110-3. .

Meanwhile, the communication system can 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 a communication system based on unlicensed bands (e.g. For example, it can be applied to licensed assisted access (LAA) communication systems.

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

Referring to FIG. 3, a radio frame 300 may include 10 subframes, and the 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 length (T _f ) may be 10 ms (millisecond), the subframe length may be 1 ms, and the slot length (T _slot ) may be 0.5 ms. Here, T _s may indicate sampling time and may be 1/30,720,000 s (second).

A slot may be composed of a plurality of OFDM symbols in the time domain and 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 the CP (cyclic prefix). CP can be classified into normal CP and extended CP. When normal CP is used, a slot may consist of 7 OFDM symbols, and in this case, a subframe may consist of 14 OFDM symbols. When an extended CP is used, a slot may consist of 6 OFDM symbols, and in this case, a subframe may consist of 12 OFDM symbols.

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

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

The radio frame 400 may include a downlink subframe, an uplink subframe, and a special subframe. Each downlink subframe and uplink subframe may include two slots. The slot length (T _slot ) may be 0.5ms. Among the subframes included in the radio frame 400, each of subframe #1 and subframe #6 may be a special subframe. For example, if the downlink-uplink switching period is 5ms, 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 can be considered a downlink section and can be used for UE cell search, time and frequency synchronization acquisition, channel estimation, etc. The guard period can be used to solve the problem of interference in uplink data transmission caused by downlink data reception delay. Additionally, the guard period may include the time required to switch from a downlink data reception operation to an uplink data transmission operation. The uplink pilot time slot can be used for uplink channel estimation, acquisition of time and frequency synchronization, etc. Transmission of a physical random access channel (PRACH) or a sounding reference signal (SRS) may be performed in the uplink pilot time slot.

The length of each downlink pilot time slot, guard period, and uplink pilot time slot included in the special subframe can be variably adjusted as needed. Additionally, the number and location of each downlink subframe, uplink subframe, and special subframe 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 encoded data through the physical layer. A short TTI may be used to support low-latency requirements in communication systems. The length of a short TTI can be less than 1ms. The existing TTI with a length of 1 ms may be referred to as base TTI or regular TTI. In other words, the basic TTI may consist of one subframe. To support transmission of basic TTI units, signals and channels can be set on a subframe basis. For example, cell-specific reference signal (CRS), physical downlink control channel (PDCCH), physical downlink shared channel (PDSCH), physical uplink control channel (PUCCH), and physical uplink shared channel (PUSCH) may exist in each subframe. You can.

On the other hand, a synchronization signal (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. Radio frames can be distinguished by SFN, and SFN is a signal with a transmission period longer than one radio frame (e.g., a paging signal, a reference signal for channel estimation, a signal indicating channel status information, etc.) Can be used to define the transmission of . The period of SFN may be 1024.

In an LTE system, PBCH may be a physical layer channel used to transmit system information (eg, master information block (MIB)). PBCH may be transmitted every 10 subframes. In other words, the transmission period of the PBCH may be 10ms, and the PBCH may be transmitted once in a radio frame. The same MIB may be transmitted during four consecutive radio frames, and after four consecutive radio frames, the MIB may be changed depending on 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 40ms. In other words, the MIB may change for each PBCH TTI.

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

The SFN that distinguishes the radio frame may consist of a total of 10 bits (B9 to B0), and among the 10 bits, the most significant bit (MSB) 8 bits (B9 to B2) are indicated by the PBCH (e.g., MIB). You can. The MSB 8 bits (B9 to B2) of the SFN indicated by the PBCH (e.g., MIB) may be the same during four consecutive radio frames (e.g., PBCH TTI). The SFN's least significant bit (LSB) 2 bits (B1 to B0) can be changed during four consecutive radio frames (e.g., PBCH TTI) and are explicitly changed by the PBCH (e.g., MIB). It may not be indicated. The LSB 2 bits (B1 to B0) of the SFN can be implicitly indicated by a scrambling sequence for PBCH (hereinafter referred to as “PBCH scrambling sequence”).

A gold sequence that is initialized with a cell ID can be used as the PBCH scrambling sequence, and the PBCH scrambling sequence is initialized every four consecutive radio frames (e.g., PBCH TTI) according to mod(SFN,4). It can be. The PBCH transmitted in the radio frame corresponding to the SFN with the LSB 2 bits (B1 to B0) set to "00" can be scrambled by a gold sequence that is initialized with the cell ID and generated. Afterwards, the gold sequences generated according to mod(SFN,4) will be used to scramble the PBCH transmitted in radio frames where the LSB 2 bits (B1 to B0) of SFN are "01", "10", and "11". You can.

Therefore, the UE, which acquired the cell ID in the initial cell search process, obtains the value of the LSB 2 bits (B1 to B0) of the SFN (e.g., "00") through the PBCH scrambling sequence during the decoding process of the PBCH (e.g., MIB). , "01", "10", and "11") can be found implicitly. The terminal uses 2 bits (B1 to B0) of the LSB of the SFN identified based on the PBCH scrambling sequence and 8 bits (B9 to B2) of the MSB of the SFN indicated by the PBCH (e.g., MIB) to generate the SFN (e.g. For example, you can check all bits (B9 to B0) of SFN.

Meanwhile, the communication system can support not only high transmission rates but also technical requirements for various service scenarios. For example, the communication system can support high transmission speed (enhanced Mobile BroadBand; eMBB), short transmission delay time (Ultra Reliable Low Latency Communication; URLLC), and massive terminal connectivity (massive Machine Type Communication; mmTC).

The subcarrier spacing of a communication system (eg, an OFDM-based communication system) may be determined based on a carrier frequency offset (CFO), etc. CFO may occur due to the Doppler effect, phase drift, etc., and may increase in proportion to the operating frequency. Therefore, to prevent performance degradation of the communication system due to CFO, the subcarrier spacing may be increased in proportion to the operating frequency. On the other hand, as the subcarrier spacing increases, CP overhead may increase. Therefore, the subcarrier spacing can be set based on channel characteristics and RF (radio frequency) characteristics according to the frequency band.

The communication system may support numerology defined in Table 1 below.

For example, the subcarrier spacing of a communication system may be set to 15 kHz, 30 kHz, 60 kHz, or 120 kHz. The subcarrier spacing in the LTE system may be 15 kHz, and in the NR system the subcarrier spacing may be 1, 2, 4, or 8 times the existing subcarrier spacing of 15 kHz. When the subcarrier spacing increases in units of an exponential multiple of 2 of the existing subcarrier spacing, the frame structure can be easily designed.

The communication system can support FR2 as well as FR1. FR2 can be classified into FR2-1 and FR2-2. FR1 may be a frequency band of 6 GHz or less, FR2-1 may be a 24.25 to 52.6 GHz band, and FR2-2 may be a 52.6 to 71 GHz band. In embodiments, FR2 may be FR2-1, FR2-2, or a frequency band including FR2-1 and FR2-2. The subcarrier spacing available for data transmission in each of FR1, FR2-1, and FR2-2 can be defined as Table 2 below. The subcarrier spacing available for SSB (synchronization signal block) transmission in each of FR1, FR2-1, and FR2-2 can be defined as in Table 3 below. The subcarrier spacing available for random access channel (RACH) transmission (e.g., Msg1 or Msg-A) in each of FR1, FR2-1, and FR2-2 can be defined as in Table 4 below.

Communication systems can support wide frequency bands (e.g., hundreds of MHz to tens of GHz). Since the diffraction and reflection characteristics of radio waves are poor in high frequency bands, propagation loss (e.g., path loss, reflection loss, etc.) in high frequency bands may be greater than propagation loss in low frequency bands. Therefore, the cell coverage of a communication system supporting a high frequency band may be smaller than the cell coverage of a communication system supporting a low frequency band. To solve this problem, a beamforming method based on a plurality of antenna elements can 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, and a hybrid beamforming method. In a communication system using a digital beamforming method, beamforming gain can be obtained using a plurality of RF paths based on a digital precoder or codebook. In a communication system using the analog beamforming method, beamforming gain can be obtained through an analog RF device (e.g., phase shifter, power amplifier (PA), variable gain amplifier (VGA), etc.) and antenna array. You can.

Since the digital beamforming method requires an expensive DAC (digital to analog converter) or ADC (analog to digital converter) and transceiver units corresponding to the number of antenna elements, the antenna is used to increase beamforming gain. The complexity of implementation may increase. In a communication system using an analog beamforming method, a plurality of antenna elements are connected to one transceiver unit through a phase shifter, so even when the beamforming gain is increased, the complexity of antenna implementation may not significantly increase. However, the beamforming performance of a communication system using an analog beamforming method may be lower than that of a communication system using a digital beamforming method. Additionally, because the phase shifter is adjusted in the time domain in a communication system using an analog beamforming method, frequency resources may not be used efficiently. Therefore, a hybrid beamforming method that is a combination of digital and analog methods can be used.

When cell coverage is increased by using the beamforming method, not only the control channel and data channel for each terminal, but also a common control channel and common signal (e.g., reference signal, synchronization signal) for all terminals belonging to the cell coverage. It may also be transmitted based on a beamforming method. In this case, the common control channel and common signal for all terminals belonging to cell coverage may be transmitted based on the beam sweeping method.

Additionally, in the NR system, SS/PBCH (synchronization block/physical broadcast channel) blocks can also be transmitted using beam sweeping. The SS/PBCH block may be composed of PSS, SSS, PBCH, etc., and within the SS/PBCH block, PSS, SSS, and PBCH may be configured in a time division multiplexing (TDM) method. In an embodiment, the SS/PBCH block may be referred to as SSB. One SS/PBCH block can be transmitted using N consecutive OFDM symbols. Here, N may be an integer of 4 or more. The base station can periodically transmit SS/PBCH blocks, and the terminal can obtain frequency/time synchronization, cell ID, system information, etc. based on the SS/PBCH blocks received from the base station. SS/PBCH block can be transmitted as follows.

Figure 5 is a conceptual diagram showing a first embodiment of a method for transmitting SS/PBCH blocks in a communication system.

Referring to FIG. 5, one or more SS/PBCH blocks within an SS/PBCH block burst set may be transmitted using a beam sweeping method. 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. L may vary depending on the range of system frequency. Within the SS/PBCH block burst set, SS/PBCH blocks can be located consecutively or dispersedly. Consecutive SS/PBCH blocks may be referred to as “SS/PBCH block burst” or “SSB burst”. The SS/PBCH block burst set may be repeated periodically, and system information (eg, MIB) transmitted through the PBCH 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.

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

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

The maximum system bandwidth supportable in an NR system may be 400 MHz. The maximum bandwidth size that can be supported by a terminal may vary depending on the terminal's capability. Therefore, the terminal can perform an initial connection procedure (for example, an initial connection procedure) using a portion of the system bandwidth of the NR system supporting broadband. To support the access procedure of terminals supporting bandwidths of various sizes, the SS/PBCH block can be multiplexed on the frequency axis within the system bandwidth of the NR system supporting broadband. In this case, the SS/PBCH block can be transmitted as follows.

Figure 7 is a conceptual diagram showing a second embodiment of a method for transmitting SS/PBCH blocks in a communication system.

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

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

The location where SSB is transmitted in the time domain may be defined differently depending on SCS (subcarrier spacing) and L value. In embodiments, SCS may mean subcarrier size. SSB may be transmitted in some symbols within one slot, and short UL transmission (e.g., Uplink control information (UCI) transmission) in the remaining symbols not used for SSB transmission within one slot. can be performed. When SSBs are transmitted on radio resources where large SCSs (e.g., 120 kHz SCS or 240 kHz SCS) are applied, include SSBs to enable long UL transmissions (e.g., transmission of URLLC traffic) at least every 1 ms. A gap may be set in the middle of consecutive slots.

Figure 8 is a conceptual diagram showing a first embodiment of SSB burst setting.

Referring to FIG. 8, in the transmission procedure of SSBs (eg, SSB burst) in radio resources to which 120 kHz SCS is applied, the base station may transmit SSBs in eight consecutive slots. In the transmission procedure of SSBs in radio resources where 240 kHz SCS is applied, the base station can transmit SSBs in 16 consecutive slots. A gap for UL transmission can be set in radio resources where 120kHz SCS or 240kHz SCS is applied.

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

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

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

In frequency bands below 6GHz, only RMSI CORESET mapping pattern #1 can be used. In frequency bands above 6 GHz, RMSI CORESET mapping patterns #1, #2, and #3 can all be used. The numerology of the SS/PBCH block may be different from the numerology of “RMSI CORESET and RMSI PDSCH”. Here, the numerology may be subcarrier spacing. Any combination of 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 = 120kHz, 60kHz or 240kHz, 120kHz" can be used. In RMSI CORESET mapping pattern #3, a combination of “SS/PBCH block, RMSI CORESET/PDSCH = 120kHz, 120kHz” can be used.

Depending on the combination of the numerology of the SS/PBCH block and the numerology of RMSI CORESET/PDSCH, one RMSI CORESET mapping pattern can be selected from RMSI CORESET mapping patterns #1-3. Setting information of RMSI CORESET may include table A and table B. Table A shows the number of resource blocks (RBs) in RMSI CORESET, the number of symbols in RMSI CORESET, and the RB (e.g., start RB or end RB) of SS/PBCH block and the RB (e.g., start RB) of RMSI CORESET. Alternatively, it may indicate an offset between end RBs. Table B may indicate the number of search space sets per slot, the offset of RMSI CORESET, and the OFDM symbol index in each of the RMSI CORESET mapping patterns. Table B may represent information for setting the monitoring occasion of RMSI PDCCH. Each of Table A and Table B may be composed of multiple tables. For example, table A may include tables 13-1 through 13-8 as specified in TS 38.213, and table B may include tables 13-9 through 13-13 as specified in TS 38.213. The size of each table A and table B may be 4 bits.

In the NR system, PDSCH can be mapped to the time domain according to PDSCH mapping type A or B. PDSCH mapping types A and B can be defined as Table 5 below.

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

Meanwhile, NR-U (unlicensed) is being discussed at the NR standardization meeting. The NR-U system can increase network capacity by improving the utilization of limited frequency resources. NR-U systems may support operation in unlicensed bands (e.g., unlicensed spectrum).

In the NR-U system, the terminal can determine whether to transmit a signal from the base station based on the Discovery Reference Signal (DRS) received from the base station, just as in the general NR system. In the NR-U system in Stand-Alone (SA) mode, the UE can obtain synchronization and/or system information based on DRS. In the NR-U system, DRS can be transmitted according to the regulations of the unlicensed band (e.g., 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 total channel bandwidth (e.g., 20 MHz).

In an NR-U system, a communication node (e.g., base station, terminal) may perform Listen Before Talk (LBT) before transmitting a signal and/or channel 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)), etc. The channel may be a downlink channel, uplink channel, sidelink channel, etc. In embodiments, signal may mean “signal”, “channel”, or “signal and channel”. LBT may be an operation to check whether a signal is transmitted by another communication node. If it is determined by the LBT that there is no signal to transmit (e.g., if the LBT is successful), the communication node may transmit the signal in the unlicensed band. If a transmission signal is determined to be present by the LBT (e.g., if the LBT fails), the communication node may be unable to transmit the signal in the unlicensed band. A communication node can perform LBT according to various categories before transmitting a signal. The category of LBT may vary depending on the type of transmission signal.

Meanwhile, NR V2X (vehicular to everything) communication technology is being discussed at the NR standardization meeting. NR V2X communication technology may be a technology that supports communication between vehicles, communication between vehicles and infrastructure, and communication between vehicles and pedestrians, etc. based on D2D (device to device) communication technology. Technologies for reducing power consumption and improving reliability for NR V2X communications are being discussed.

NR V2X communication (e.g., sidelink communication) is performed according to three transmission methods (e.g., unicast method, broadcast method, groupcast method). You can. When the unicast method is used, a PC5-RRC connection may be established between a first terminal (e.g., a transmitting terminal that transmits data) and a second terminal (e.g., a receiving terminal that receives data), PC5-RRC connection may mean a logical connection to a pair between the source ID of the first terminal and the destination ID of the second terminal. The first terminal may transmit data (eg, sidelink data) to the second terminal. When the broadcast method is used, the first terminal can transmit data to all terminals. When the group cast method is used, the first terminal can transmit data to a group (eg, group cast group) consisting 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)) about data received from the first terminal to the first terminal. In the embodiments below, feedback information may be referred to as “HARQ-ACK,” “feedback signal,” “physical sidelink feedback channel (PSFCH) signal,” etc. 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) method. 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 the broadcast method is used, the transmission procedure for feedback information about data may not be performed. For example, system information may be transmitted in a broadcast manner, and the terminal may not transmit feedback information about the system information to the base station. Therefore, the base station may not know whether system information has been successfully received from the terminal. To solve this problem, the base station can periodically broadcast system information.

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

Two HARQ-ACK feedback methods (eg, transmission procedures of feedback information) may be supported in groupcast sidelink communication. “When the number of receiving terminals in the sidelink group is large and service scenario 1 is supported,” some receiving terminals within a specific range within 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, instead of all receiving terminals in the sidelink group, some receiving terminals within a specific range may be allowed to receive in a best-effort manner. Service scenario 1 may be an extended sensor scenario in which some receiving terminals within a specific range need to receive the same sensor information from the transmitting terminal. In embodiments, a transmitting terminal may refer to a terminal that transmits data, and a receiving terminal may refer to a terminal that receives data.

“If the number of receiving terminals in the sidelink group is limited and service scenario 2 is supported,” each of all receiving terminals belonging to the sidelink group can 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, because 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 from all receiving terminals belonging to the sidelink group. It can be.

Like broadcast sidelink communication, data in unicast sidelink communication and groupcast sidelink communication can be transmitted and received without a HARQ-ACK feedback procedure. In this case, in order to increase the probability of receiving data, the transmitting terminal may retransmit data a preset number of times.

In all transmission methods (e.g., unicast transmission, groupcast transmission, broadcast transmission), whether or not the HARQ-ACK feedback procedure is applied depends on signaling (e.g., signaling of system information, PC5-RRC signaling, UE-specific It can be set to the terminal(s) fixedly or semi-fixably through (RRC signaling, signaling of control information). In sidelink communication, HARQ-ACK feedback information may be transmitted on PSFCH. If PSSCH reception is successful, the receiving terminal may transmit an ACK for PSSCH (eg, data) on PSFCH. If PSSCH reception fails, the receiving terminal may transmit a NACK for PSSCH (eg, data) on PSFCH. PSFCH may be a channel for reporting ACK/NACK information (eg, HARQ-ACK feedback) to the transmitting terminal. A resource area (eg, PSFCH resource area) for PSFCH transmission (eg, transmission of HARQ-ACK feedback) within a specific resource pool may be set in advance. PSFCH (eg, PSFCH resource, PSFH resource area) may be configured periodically. The PSFCH period for PSFCH resources may be k slots (eg, logical sidelink (SL) slots). k may be a natural number. For example, k can be 1, 2, or 4.

Figure 10 is a conceptual diagram showing a first embodiment of slot configuration in which PSFCH is configured.

Referring to FIG. 10, within a slot (e.g., SL slot), PSFCH (e.g., HARQ-ACK feedback) may be repeatedly transmitted in two symbols (e.g., two OFDM symbols) . The first of the two symbols through which the PSFCH is transmitted can be used for automatic gain control (AGC) to properly adjust the PSFCH reception power level.

PSFCH can be transmitted within a frequency resource area preset by system information. In this case, the frequency resource area for PSFCH transmission may be indicated (e.g., signaled) in the form of a bitmap within the resource pool. The receiving terminal may implicitly select the location of the frequency resource region for PSFCH transmission based on the slot and subchannel index in which the PSSCH was received. The receiving terminal can check the number of PSFCH resources that can be multiplexed based on RB (resource block) and cyclic shift of the PSFCH sequence within the frequency resource region. The receiving terminal may implicitly select the PSFCH index for the PSFCH resource(s) based on the source ID (identifier) and member ID. The source ID may be a physical layer source ID. The source ID may be the ID of the transmitting terminal that transmitted the PSSCH.

Member ID can be used in groupcast HARQ-ACK feedback option 2. When groupcast HARQ-ACK feedback option 2 is applied, each of all receiving terminals in the group may individually transmit HARQ-ACK feedback for SL data through a separate PSFCH (eg, PSFCH resource). In cases different from the above embodiment, the member ID may be set to 0.

Figure 11 is a conceptual diagram showing a first embodiment of PSFCH for ACK/NACK transmission.

Referring to FIG. 11, the transmission time of the PSFCH may be the first slot (e.g., PSFCH slot) in which PSFCH transmission is possible after a preset time (e.g., sl-MinTimeGapPSFCH ) from the time of reception of the PSSCH. The PSFCH slot may be a slot capable of PSFCH transmission and/or a slot in which PSFCH is configured. sl-MinTimeGapPSFCH is to be set considering “time for processing the PSSCH after reception of the PSSCH” and “time to prepare ACK/NACK (e.g., HARQ-ACK feedback) depending on successful reception of the PSSCH.” You can. sl-MinTimeGapPSFCH can be set to 2 or 3 slots. The terminal (e.g., receiving terminal) may transmit the PSFCH in slot #n+12, which is a slot in which PSFCH transmission is possible after sl-MinTimeGapPSFCH (e.g., three slots) from the point of reception of the PSSCH. n may be an integer greater than or equal to 0. In the present disclosure, the reception time may mean a reception start time and/or a reception end time, and the transmission time may mean a transmission start time and/or a transmission end time. A point in time may mean time and/or duration.

Data reliability at 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 alleviated by appropriately adjusting the power of the transmitting terminal. Energy efficiency can be improved by reducing unnecessary transmission power. Power control methods can be classified into open-loop power control methods and closed-loop power control methods. In the open-loop power control method, the transmitting terminal can determine the transmit power by considering settings and measured environments. In the closed-loop power control method, the transmitting terminal can determine the transmit power based on a transmit power control (TPC) command received from the receiving terminal.

Predicting the received signal strength at the receiving terminal may be difficult due to various causes including multi-path fading channels, interference, etc. Therefore, the receiving terminal can adjust the received power level (eg, 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 can perform an AGC operation using a reference signal received from a base station. However, in sidelink communication (e.g., V2X communication), the reference signal may not be transmitted from the base station. In other words, in sidelink communication, communication between terminals can be performed without a base station. Therefore, it may be difficult to perform AGC operation in sidelink communication. In sidelink communication, the transmitting terminal may first transmit a signal (e.g., a reference signal) to the receiving terminal before transmitting data, and the receiving terminal may perform an AGC operation based on the signal received from the transmitting terminal, thereby maintaining the received power range. (For example, the received power level) can be adjusted. Afterwards, the transmitting terminal can transmit sidelink data to the receiving terminal. The signal used for AGC operation may be a duplicated signal for a signal to be transmitted later or a signal preset between terminals.

The time interval required for AGC operation may be 15 μs. In the NR system, when the subcarrier spacing is 15 kHz, the time interval (e.g., length) of one symbol (e.g., OFDM symbol) may be 66.7 μs. In the NR system, when the subcarrier spacing is 30 kHz, the time interval of one symbol (eg, OFDM symbol) may be 33.3 μs. In the embodiments below, the symbol may refer to an OFDM symbol. In other words, the time interval of one symbol may be more than twice the time interval required for AGC operation.

For sidelink communication, transmission of a data channel for data transmission and a control channel containing 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).

FIG. 12 is a conceptual diagram illustrating embodiments of a method for 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. If Option 1A and/or Option 1B are supported, the control channel and data channel may be multiplexed in the time domain. If option 2 is supported, control channels and data channels can be multiplexed in the frequency domain. If option 3 is supported, control channels and data channels can be multiplexed in time and frequency domains. Sidelink communication can support option 3 by default.

In sidelink communication (e.g., NR-V2X sidelink communication), the basic unit of resource configuration may be a subchannel. Subchannels can be defined by time and frequency resources. For example, a subchannel may be composed of a plurality of symbols (eg, OFDM symbols) in the time domain and may be composed 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 (e.g., NR-V2X sidelink communication), transmission resources may be allocated based on mode 1 or mode 2. When mode 1 is used, the base station can allocate sidelink resources for data transmission within the resource pool to the transmitting terminal, and the transmitting terminal receives data using the sidelink resources allocated by the base station. It can be transmitted to the terminal. Here, the transmitting terminal may be a terminal that transmits data in sidelink communication, and the receiving terminal may be a terminal that receives data in sidelink communication.

When mode 2 is used, the transmitting terminal selects the side to use for data transmission by performing a resource sensing operation (e.g., resource sensing procedure) and/or a resource selection operation (e.g., resource selection procedure) within the resource pool. Link resources can be selected autonomously. The base station can set 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 from the resource pool for mode 2. Alternatively, a common resource pool may be established for Mode 1 and Mode 2.

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

Figure 13 is a conceptual diagram showing a first embodiment of a resource selection operation.

Referring to FIG. 13, a terminal (e.g., a transmitting terminal) may perform a resource sensing operation within a sensing window, and the sensed resource(s) (e.g., candidate resource(s)) within the selection window. A resource selection operation can be performed for . When the resource selection operation is triggered at n, the terminal detects the sensing result (e.g., the resource(s) sensed by the resource sensing operation) within the sensing window (e.g., the interval from nT ₀ to nT _proc,0 ). ) Based on this, appropriate resource(s) can be selected within the selection window (e.g., the interval from n+T ₁ to n+T ₂ ).

The terminal may exclude candidate resource(s) that do not satisfy the conditions within the selection window based on the results of the resource sensing operation. In other words, the terminal can determine the remaining candidate resources by excluding unsuitable candidate resource(s) from all candidate resources. If the ratio of the remaining candidate resources among all resources in the selection window is less than the reference ratio, the terminal may relax the conditions for excluding the candidate resource(s). For example, the terminal may increase the reference signal received power (RSRP) threshold by 3 dB, which is a condition for excluding candidate resource(s). Afterwards, the terminal can perform the resource selection operation again. The reference ratio can be preset to one of 20%, 35%, or 50% for each priority. If the ratio of the remaining candidate resources is greater than the reference ratio, the terminal may randomly select the final resource(s) used for SL transmission among the remaining candidate resources. The terminal may perform SL transmission using the final resource(s).

Figure 14 is a conceptual diagram showing a first embodiment of a resource re-selection operation.

Referring to FIG. 14, after the resource selection operation, the terminal may perform a resource re-selection operation by considering aperiodic data transmission, etc. After performing the operations shown in FIG. 13, the terminal may perform a resource re-selection operation by additionally considering the sensing result before actual SL transmission (mT ₃ ). A resource re-selection operation may be performed within a re-selection window. The terminal may additionally determine the suitability of the resource(s) reserved in m. If the reserved resource(s) in m are determined to be suitable, the terminal can perform SL transmission using the reserved resource(s). If the resource reserved in m is determined to be unsuitable, the terminal may re-select resource(s) for SL transmission and perform SL transmission using the re-selected resource(s).

If an independent SL carrier is not configured in SL communication, some UL resources among UL resources may be configured as SL resources through the SL resource pool configuration procedure. Among the slots within a specific period, the bitmap may be repeatedly applied to the remaining slot(s) except for the slot(s) in which at least X can be a natural number. The bitmap may indicate slot(s) used as SL resources. For example, slot(s) corresponding to bit(s) set to 1 among the bits in the bitmap can be used as SL resources.

It can be assumed that “15 kHz SCS (subcarrier spacing) is applied and more than X UL symbols are set in all slots.” "If there are 10240 available slots in the DFN (direct frame number), the transmission cycle of S-SSB is 160ms, and there are two slots used for S-SSB transmission in each transmission cycle of S-SSB. ", The number of slots used for S-SSB transmission within the DFN may be 128. The bitmap for setting SL time resources may include 10 bits. If the bitmap (e.g., a bitmap containing 10 bits) is repeatedly applied to the remaining 10112 slots excluding the 128 slots used for S-SSB transmission in the 10240 slots, the bitmap is applied. There may be two slots (e.g., reserved slots) that are not used. It may be necessary to exclude two spare slots. Excluding the two spare slots from the 10112 slots, 10110 slots can remain. The bitmap (for example, a bitmap including 10 bits) may be applied repeatedly 1011 times to 10110 slots. “If the bitmap is 1111000000 and the slot corresponding to the bit set to 1 is used as a SL resource,” 4044 slots within the DFN can be set as SL resources. In other words, among 10240 slots, 4044 slots can be used for SL communication by setting the SL resource pool.

A sidelink communication system supporting Rel-16 can be designed for terminals that do not have significant restrictions on battery capacity (e.g., terminals mounted in automobiles, vehicle UE (V-UE)). Therefore, power saving issues may not be greatly considered in the resource sensing/selection operation of the terminal. In a sidelink communication system that supports Rel-17, terminals with limitations on battery capacity (e.g., terminals carried by pedestrians, terminals mounted on bicycles, terminals mounted on motorcycles, P-UE (pedestrian UE) ), power saving methods will be needed for sidelink communication. In the present disclosure, V-UE may refer to a terminal without significant restrictions on battery capacity, P-UE may refer to a terminal with restrictions on battery capacity, and “resource sensing/selection operation” refers to “resource It may include “a sensing operation and/or a resource selection operation.” 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. Additionally, in this disclosure, “operation of the terminal” may be interpreted as “operation of the V-UE” and/or “operation of the P-UE.”

To save power in LTE V2X, partial sensing operations and/or random selection operations may be introduced. When a partial sensing operation is supported, the terminal can perform a resource sensing operation in a partial section within the sensing window instead of the entire section, and select a resource based on the results of the partial sensing operation. According to this operation, the power consumption of the terminal can be reduced.

In Rel-14 LTE V2X, only periodic data transmission and reception operations may be possible. In Rel-14 LTE V2X, the terminal can randomly select candidate slots by considering the minimum number preset in the resource selection section (e.g., selection window), and perform partial sensing operations by considering a period of k × 100 ms. can do. k may be signaled by a bitmap (e.g., a bitmap containing 10 bits). k may be determined depending on the location of the bitmap (e.g., bits included in the bitmap). For example, the 10 bits included in the bitmap may correspond to numbers 1 to 10 starting from the MSB, and the period may be determined based on the value corresponding to the bit set to 1. The value corresponding to the bit set to 1 may be k.

If MSB is set to 1 in the bitmap, k may be 1. In this case, the terminal can perform a partial sensing operation considering a 100ms (=1×100ms) period. If the bit following the MSB in the bitmap is set to 1, k may be 2. In this case, the terminal can perform a partial sensing operation considering a 200ms (=2×100ms) period. If LSB is set to 1 in the bitmap, k may be 10. In this case, the terminal can perform a partial sensing operation considering a 1000ms (=10×100ms) period.

In Rel-14 LTE V2X, the period (for example, the period of partial sensing operation) can be set to 20ms or 50ms. The 20ms period or 50ms period may not be supported in the resource pool for P-UE. In NR communication system {0, 100ms, 200ms, … In addition to the , 1000ms} period, shorter periods can be supported. Short periods are {1ms, 2ms, … , 99ms}. Up to 16 periods can be selected from the resource pool, and the selected periods can be preset in the terminal. The terminal may perform a resource sensing operation and/or a resource (re)selection operation using one or more of the set periods. If the random selection operation is supported, the terminal can randomly select a resource without performing a resource sensing operation. Alternatively, the random selection operation may be performed together with the resource sensing operation. For example, the terminal can determine a resource by performing a resource sensing operation and can select resource(s) by performing a random selection operation within the determined resources.

In LTE V2X supporting Rel-14, a resource pool capable of performing partial sensing operations and/or random selection operations can be set independently of the resource pool capable of performing complete sensing operations. A resource pool capable of performing a random selection operation, a resource pool capable of performing a partial sensing operation, and a resource pool capable of performing a random selection operation and a partial sensing operation may be set independently. In other words, a random selection operation, partial sensing operation, or “random selection operation and partial sensing operation” may be set in each resource pool. When both the random selection operation and the partial sensing operation are set in the resource pool, the terminal can select one operation from the random selection operation and the partial sensing operation, select the resource by performing the selected operation, and use the selected resource to select the side Link communication can be performed.

In LTE V2X that supports Rel-14, SL data can be transmitted periodically based on a broadcast method. In an NR communication system, SL data may be transmitted based on at least one of a broadcast method, a multicast method, a groupcast method, or a unicast method. Additionally, in the NR communication system, SL data may be transmitted periodically or aperiodically. The transmitting terminal may transmit SL data to the receiving terminal, and the receiving terminal may transmit HARQ-ACK feedback (eg, ACK or NACK) for the SL data to the transmitting terminal through PSFCH. In the present disclosure, a transmitting terminal may refer to a terminal that transmits SL data, and a receiving terminal may refer to a terminal that receives SL data.

A terminal with reduced capability (hereinafter referred to as a “RedCap terminal”) can operate in a specific usage environment. The capacity of the RedCap terminal may be lower than that of the NR (new radio) normal terminal, LTE-MTC (machine type communication) terminal, NB (narrow band)-IoT (internet of things) terminal, and LPWA (Low Power Wide Area) may be higher than the capabilities of each terminal. For example, a terminal (e.g., surveillance camera) requiring “high data rate and non-high latency conditions” and/or “non-high data rate, high latency conditions, and high reliability ( A terminal (eg, a wearable device) that requires “reliability” may exist. To support the above-described terminals, the maximum carrier bandwidth in FR1 may be reduced from 100 MHz to 20 MHz, and in FR2 the maximum carrier bandwidth may be reduced from 400 MHz to 100 MHz. The number of reception antennas of a Redcap terminal may be smaller than the number of reception antennas of a NR general terminal. If the carrier bandwidth and the number of reception antennas decrease, reception performance in the RedCap terminal may decrease, and coverage of the RedCap terminal may accordingly decrease.

Communication systems (e.g., NR systems) may operate in frequency bands higher than the 52.6 GHz frequency band. As the frequency band in which the communication system operates increases, frequency offset error and phase noise may increase. The use of a large SCS may be necessary for robust operation in these environments. In the FR2 band, 60kHz SCS and/or 120kHz SCS may be supported, and in addition, 480kHz SCS and/or 960kHz SCS may be supported. Additionally, “physical layer signal and channel design” and “physical layer procedures” according to the new SCS may be required. Regarding the initial connection procedure, 120kHz SSB and/or 240kHz SSB may be supported in the FR2 band, and additionally 480kHz SSB and/or 960kHz SSB may be supported. Here, 120kHz SSB may refer to SSB transmitted in a radio resource to which 120kHz SCS is applied, and 240kHz SSB may refer to an SSB transmitted in a radio resource to which 240kHz SCS is applied. To support the new SCS, “Initial BWP Setup Method” and “SSB Burst Aggregation Pattern” may be required.

Carrier aggregation (CA) to improve data transmission rates on sidelinks at Rel-18, support for operation in unlicensed spectrum, improved performance in FR2 licensed spectrum, and/or co-channel coexistence between LTE SL and NR SL Technologies for (co-channel coexistence) can be discussed. In the initial ITS (intelligent transport systems) band, C-V2X (cellular V2X) services were supported for LTE SL terminals, but over time, they may also be supported for NR SL terminals. Ultimately, C-V2X services can be provided mainly to NR SL terminals. An LTE SL terminal may refer to a terminal that supports LTE SL communication, and an NR SL terminal may refer to a terminal that supports NR SL communication. ITS bands may be limited by limited resources. Considering the above situations, coexistence of the same channel between the LTE SL terminal and the NR SL terminal includes smooth migration between LTE SL communication and NR SL communication, smooth service continuity through re-farming of frequency resources, and/or may be necessary to increase resource efficiency.

The following two methods can be discussed for same-channel coexistence between LTE SL terminal and NR SL terminal.

- First method: resource pool separation between two RATs (radio access technology)

- Second method: Dynamic resource sharing using overlapping resource pools between two RATs

When the first method is used, the resource pool of LTE SL and the resource pool of NR SL can be distinguished. If the second method is used, resources (eg, resource pools) between LTE SL and NR SL may overlap. Within overlapping resources, resources may be shared dynamically, and LTE SL communication and/or NR SL communication may be performed in the shared resources. According to the first method, resources for LTE SL communication and resources for NR SL communication may be set independently, and resources for LTE SL communication and resources for NR SL communication may not overlap with each other. Therefore, LTE SL communication and NR SL communication can be performed without problems.

According to the first method, it may be difficult to flexibly allocate resources according to the occupancy rate of the LTE SL terminal and/or NR SL terminal. If the base station does not pre-allocate resources to an out of coverage (OCC) terminal, the OCC terminal can perform SL communication using preset default resources. The OCC terminal may refer to a terminal located outside the coverage of the base station (eg, an LTE SL terminal and/or an NR SL terminal). It can be preset that LTE SL terminals to which services are initially provided occupy most of the resources in the ITS band, and new services for NR SL terminals can be provided over time. Default resources for NR SL terminals may be set to resources other than the default resources set for LTE SL terminals within the ITS band. Resources other than default resources configured for LTE SL terminals within the ITS band may be very small. In this case, only some default resources for NR SL terminals can be set. Alternatively, default resources for NR SL terminals may not be set. In this case, efficient use of resources may not be possible.

Considering the introduction of the NR SL terminal, the default resources of the LTE SL terminal may be set to be limited. In this case, efficient use of resources may be limited and initial system performance may deteriorate. Resetting and/or modifying default resources set in the terminal may not be possible until the terminal is replaced. Therefore, setting the default resources of the LTE SL terminal to be limited may not be desirable in terms of resource efficiency. In this disclosure, the terminal may be interpreted as an LTE SL terminal, an NR SL terminal, or an “LTE SL terminal and an NR SL terminal” depending on the context.

Considering the above problems, it may be desirable to support the second method. In other words, it may be desirable to support a method of dynamically sharing overlapping resources between LTE SL terminals and NR SL terminals. To support the second scheme, when the LTE SL terminal and the NR SL terminal operate on the same resource, methods for mitigating collisions and/or interference between the LTE SL terminal and the NR SL terminal may be required. In this disclosure, resource sharing methods between the LTE SL terminal and the NR SL terminal will be proposed in a situation where the LTE SL terminal and the NR SL terminal coexist. In other words, if the second method is used, methods for sharing resources between terminals will be proposed. The present disclosure can be applied not only to environments where the second method is used, but also to environments where the first method is used.

The NR SL terminal can operate based on mode 1 or mode 2. If the NR SL terminal supports mode 1, resources for the NR SL terminal (eg, resources for SL communication) may be set by the base station. If the NR SL terminal supports mode 2, the NR SL terminal can select resources on its own based on the results of the resource sensing operation. The LTE SL terminal can operate based on mode 3 or mode 4. If the LTE SL terminal supports mode 3, resources for the LTE SL terminal (eg, resources for SL communication) may be set by the base station. If the LTE SL terminal supports mode 4, the LTE SL terminal can select resources on its own based on the results of the resource sensing operation.

Based on the type of terminal and the modes supported by the terminal, combinations listed in Table 6 below can be considered.

In case 1, the LTE SL terminal can support mode 3, and the NR SL terminal can support mode 1. In other words, in case 1, both the LTE SL terminal and the NR SL terminal can be controlled by the base station and can perform SL communication using resources set by the base station. Therefore, even when overlapping resources are shared between the LTE SL terminal and the NR SL terminal, collision and/or interference problems may not occur. In Case 2 and Case 3, the LTE SL terminal and the NR SL terminal can select resources based on different methods. Cases 2 and 3 may not be considered because they are not common situations. In case 4, the LTE SL terminal can support mode 4, and the NR SL terminal can support mode 2. In other words, in case 4, both the LTE SL terminal and the NR SL terminal can select resources on their own based on the results of the resource sensing operation. In Case 4, a method for sharing resources between the LTE SL terminal and the NR SL terminal may be necessary.

In an environment where an LTE SL terminal and an NR SL terminal coexist, an LTE SL terminal (e.g., a terminal supporting Rel-15) cannot know the existence of the NR SL terminal. Terminals equipped with the LTE SL communication module and the NR SL communication module (e.g., terminals introduced after Rel-16) have some coexistence functions in an environment where two RATs (e.g., LTE, NR) coexist. Support is available. In an environment where two RATs coexist, transmission and reception operations can be performed based on priority. The LTE SL communication module may be referred to as an LTE SL module (or LTE module), and the NR SL communication module may be referred to as an NR SL module (or NR module). Active coexistence between LTE SL terminals and NR SL terminals can be supported by dynamic resource sharing between two RATs in Rel-18.

For dynamic resource sharing between two RATs, the terminal can be assumed to be equipped with both an LTE SL module and an NR SL module. A resource area that supports dynamic resource sharing between two RATs can be set as a unit of resource pool. The configuration information of the resource area that supports dynamic resource sharing may be included in the system information that configures the resource pool. For example, the configuration information may include an indicator supporting whether dynamic resource sharing is supported. The size of the indicator may be 1 bit. An indicator with a size of 1 bit may be referred to as a “1-bit indicator.” The indicator set to the first value may indicate that the dynamic resource sharing function is enabled. The indicator set to the second value may indicate that the dynamic resource sharing function is disabled. If the resource pool is set to support dynamic resource sharing, the terminal can perform an NR SL resource selection operation based on the sensing results of the LTE SL module. In this disclosure, a terminal may refer to a terminal equipped with an LTE SL module and an NR SL module.

[Resource selection method using LTE SL information]

A terminal equipped with an LTE SL module and an NR SL module can perform LTE SL resource sensing operations and NR SL resource sensing operations simultaneously. The LTE SL resource sensing operation may refer to a resource sensing operation for LTE SL communication, and the NR SL resource sensing operation may refer to a resource sensing operation for NR SL communication. The results of the resource sensing operation performed by the LTE SL module may be transmitted to the NR SL module. The NR SL module can select resources for transmission of SL data based on the results of the resource sensing operation of the LTE SL module. In other words, the terminal may perform an NR SL resource selection operation based on the results of the LTE SL resource sensing operation. The result of the resource sensing operation may be referred to as “sensing result” or “sensing information.” Sensing results (or sensing information) may include candidate resource(s). The sensing result transmitted from the LTE SL module in one terminal to the NR SL module is "candidate resource(s) used for the transmission operation of the LTE SL module" and/or "candidate resource(s) on which the reception operation of the LTE SL module is performed ( field)". Alternatively, the sensing result transmitted from the LTE SL module in one terminal to the NR SL module may be “resource(s) that the LTE SL module determines to be used by another terminal (eg, another LTE terminal).”

Information on candidate resource(s) used for the transmission operation and/or reception operation of the LTE SL module may be processed by an in-device coexistence procedure. It may be desirable for information on resource(s) that the LTE SL module determines to be used by another terminal (e.g., another LTE terminal) to be transferred from the LTE SL module to the NR SL module. The terminal may perform a resource selection operation (eg, an LTE SL resource selection operation or an NR SL resource selection operation) based on the sensing results of the NR SL module and the sensing results of the LTE SL module. The sensing result of the NR SL module may be referred to as “NR SL sensing result”, “NR SL sensing information”, “NR sensing result”, or “NR sensing information”, and the sensing result of the LTE SL module may be referred to as “LTE SL sensing It may be referred to as “result”, “LTE SL sensing information”, “LTE sensing result”, or “LTE sensing information”.

The terminal may exclude resources determined to be used by other terminals (e.g., other NR terminals) from candidate resources based on the NR SL sensing results, and may additionally exclude resources determined to be used by other terminals (e.g., other NR terminals) based on the LTE SL sensing results. For example, resources determined to be used by (other LTE terminals) can be excluded from candidate resources. The NR module may receive the LTE SL sensing result from the LTE module, and determine that the LTE SL candidate resource completely or partially overlaps with the NR SL candidate resource based on the LTE SL sensing result. In this case, the NR module can exclude NR SL candidate resources from existing candidate resources. LTE SL candidate resources may be LTE SL sensing results, and NR SL candidate resources may be NR SL sensing results. The NR module may refer to an NR SL module, and the LTE module may refer to an LTE SL module.

In a resource selection operation, candidate resources may be excluded based on sensing results. Additionally, “resources on which a resource sensing operation for SL transmission has not been performed” and/or “resources on which an SL reception operation has not been performed” may be excluded from candidate resources. In this case, not only the transmission resources of the NR SL module (e.g., resources on which resource sensing operations are not performed due to SL transmission) but also the transmission resources of the LTE SL module (e.g., resources on which resource sensing operations are not performed due to SL transmission) It may be desirable to exclude resources that are not available from the list of candidate resources.

In order to easily perform the operation of excluding NR SL candidate resources based on LTE SL information, it may be desirable to set a NR SL non-preferred candidate resource set based on LTE SL information. The NR SL module (e.g., a terminal) has NR SL candidate resource(s) overlapping with resources (e.g., resources used by other LTE terminal(s)) according to the LTE SL information received from the LTE SL module. Can be set to NR SL non-preferred candidate resource set. The NR SL module (e.g., a terminal) may compare the NR SL non-preferred candidate resource(s) with the existing NR SL candidate resource(s), and compare the NR SL non-preferred candidate resource(s) and the existing NR SL candidate resource(s). Candidate resource(s) overlapping between can be excluded from the existing NR SL candidate resource(s). LTE SL information received from the LTE SL module includes resource information reserved by the LTE terminal(s) (e.g., location information of time and/or frequency resources, subframe information, subchannel information), and the reserved resources. measurement information (e.g., RSRP), period of the reserved resource (e.g., reservation period), resource information used for SL transmission operation of the LTE SL module (e.g., time and/or frequency resources location information, resource reservation cycle), resource information not monitored by the SL transmission operation of the LTE SL module (e.g., location information of time and/or frequency resources), priority, RSSI (received signal) strength indicator), or information on the LTE SL reference time. Priority may mean priority of data and/or priority of transmission.

In the resource selection operation, NR SL candidate resource(s) (e.g., candidate single-slot resource(s)) that partially or fully overlap with the resource area indicated by the LTE SL information received from the LTE SL module ) may be desirable to exclude. It may be desirable for NR SL candidate resource(s) that satisfy the condition(s) considering LTE SL subcarrier spacing (SCS) and NR SL SCS to be excluded from the resource selection operation. LTE SL SCS may refer to an SCS applied to LTE SL communication, and NR SL SCS may refer to an SCS applied to NR SL communication. LTE SL SCS may be referred to as SCS _LTE , and NR SL SCS may be referred to as SCS _NR .

In the time domain, NR SL slot(s) corresponding to the subframe indicated by LTE SL information (eg, LTE subframe) may be selected. At this time, when SCS _LTE and SCS _NR are the same (for example, when SCS _LTE and SCS _NR are 15 kHz), one LTE subframe may correspond to one NR SL slot. When SCS _LTE and SCS _NR are different, one LTE subframe may correspond to SCS _NR /SCS _LTE NR SL slot(s). For example, when SCS _LTE is 15kHz and SCS _NR is 30kHz, the UE can select 2 (=30kHz/15kHz) NR SL slots corresponding to one LTE subframe. Period information from the LTE SL module If is additionally received (for example, when LTE SL information also includes period information), the terminal can consider periodic time resources by applying the period information to LTE subframe information.

In the frequency domain, NR SL candidate resource(s) that partially or completely overlap with a subchannel (eg, LTE subchannel) indicated by LTE SL information may be selected. Overlapping of some frequency resources (e.g., frequency domains) means “some of the subchannel(s) overlapping,” “some of the RB(s) within the subchannels overlapping,” and/or “some of the RB(s) within the RBs overlapping”. It may mean “overlapping frequency resource(s).” If the LTE SL SCS and NR SL SCS are different, some frequency resource(s) within the RB may overlap.

The UE may exclude NR SL candidate resource(s) that satisfy the above-described overlap condition(s) in the time and frequency domains from the resource selection operation. If the LTE SL module provides RSRP information, the terminal can perform an NR SL resource selection operation by considering the RSRP information of the LTE SL. For example, the UE may exclude NR SL candidate resources that overlap with LTE SL candidate resources having an RSRP greater than a threshold (eg, RSRP threshold) from the resource selection operation. Candidate resources (eg, NR SL candidate resources) excluded from the resource selection operation may not be used in NR SL communication. If the LTE SL module provides priority information, the terminal may perform an NR SL resource selection operation by considering the priority of the LTE SL (e.g., data priority, transmission priority). If the priority of the NR SL candidate resource that satisfies the overlap condition(s) in the time and frequency domain is lower than the priority of the LTE SL candidate resource, the terminal may exclude the NR SL candidate resource from the resource selection operation. Information on the priority of LTE SL candidate resources may be included in LTE SL information provided by the LTE SL module.

If the RSRP of the LTE SL transmission resource reserved by another terminal is higher than “the priority of the NR SL transmission resource and the RSRP threshold based on the priority of the LTE SL transmission resource”, the NR SL corresponding to the reserved LTE SL transmission resource Candidate resources may be excluded from the resource selection operation. The RSRP threshold may be a value set for an NR SL resource selection operation (eg, an existing NR SL resource selection operation) or an LTE SL resource selection operation (eg, an existing LTE SL resource selection operation). Alternatively, the RSRP threshold may be a newly set value separate from the “value set for the NR SL resource selection operation and/or the LTE SL resource selection operation.”

In addition to the overlapping condition(s) in the time and frequency domain, some or all of one or more additional conditions may be considered in the resource selection operation. Whether one or more additional conditions apply may be set in the terminal through signaling (e.g., signaling of system information, UE-specific RRC signaling, PC5-RRC signaling). Applicability of one or more additional conditions can be set for each resource pool.

NR SL non-preferred candidate resources may be determined based on LTE SL information. NR SL non-preferred candidate resources may be excluded from NR SL candidate resources. If the criteria for delivering the remaining NR SL candidate resources to the upper layer are not met, the remaining NR SL candidate resources may not be delivered to the upper layer. NR SL candidate resources excluded based on the RSRP of the LTE SL candidate resource may be added back to the NR SL candidate resource. For example, if the ratio of remaining NR SL candidate resources to all resources is less than X%, the remaining NR SL candidate resources may not be delivered to the upper layer. Among the excluded NR SL candidate resources, excluded NR SL candidate resources that overlap with the LTE SL candidate resource with a small RSRP may be preferentially added to the NR SL candidate resource. Alternatively, among the excluded NR SL candidate resources, the excluded NR SL candidate resource having an RSRP that is higher or lower than the RSRP of the LTE SL candidate resource may be preferentially added to the NR SL candidate resource. Alternatively, the UE may increase the RSRP threshold by a specific value (e.g., 3 dB) and perform a resource selection operation using the increased RSRP threshold. As another method, the UE may randomly select at least one excluded NR SL candidate resource among the excluded NR SL candidate resources and add the selected at least one excluded NR SL candidate resource to the NR SL candidate resource. there is. The specific value may be set in the terminal through signaling (e.g., signaling of system information, UE-specific RRC signaling, PC5-RRC signaling, signaling of control information). If the specific value is not set in the terminal, the terminal can determine the specific value by implementation.

LTE SL resource sensing operation may be different from NR SL resource sensing operation. The LTE SL terminal may determine a candidate resource set (e.g., S _A ) based on the measurement result of SCI and/or RSRP, and then determine a final candidate resource set (e.g., S _B ) can be determined. Information on the final candidate resource set may be transmitted to the upper layer of the LTE SL terminal. An LTE SL terminal (eg, a higher layer entity) may perform a resource selection operation based on the final candidate resource set. In other words, the LTE SL terminal can select the final transmission resource within the final candidate resource set. A final candidate resource set (e.g., final candidate resources) may be considered a resource not used by other LTE SL terminal(s), and resources not belonging to the final candidate resource set may be used by other LTE SL terminal(s). It can be considered to be used by . To avoid collisions with other LTE SL terminal(s), it may be desirable to exclude resources that do not belong to the final candidate resource set and overlapping resources from the NR SL candidate resource(s).

The NR SL module may receive information on a final candidate resource set (eg, final candidate resources) from the LTE SL module, and may perform an NR SL resource selection operation by considering the final candidate resource set. If information on the final candidate resource set is not received from the LTE SL module, the NR SL module may perform the NR SL resource selection operation without considering the final candidate resource set of the LTE SL module. Whether to transmit information on the final candidate resource set of the LTE SL module can be set through signaling (e.g., signaling of system information, UE-specific RRC signaling, PC5-RRC signaling, signaling of control information). Whether to transmit information on the final candidate resource set of the LTE SL module can be set for each resource pool.

[Resource setting method for coexistence between LTE SL terminal and NR SL terminal]

It may be desirable to set NR SL resources in consideration of LTE SL resource settings. The LTE SL subchannel can be established based on two methods. In the first method, the PSSCH resource and the PSSCH resource may be set adjacent to each other in the frequency domain. In the second method, the PSCCH resource and PSSCH resource in the frequency domain can be set apart. In other words, in the frequency domain, PSCCH resources and PSSCH resources may be set to be non-adjacent.

FIG. 15A is a conceptual diagram illustrating a first embodiment of a method for configuring PSCCH resources and PSSCH resources to be adjacent, and FIG. 15B is a conceptual diagram illustrating a first embodiment of a method for configuring PSCCH resources and PSSCH resources to be non-adjacent. .

Referring to FIG. 15A, PSCCH resources and PSSCH resources may be set adjacent to each other in the frequency domain based on frequency division multiplexing (FDM). The frequency resource of the PSCCH may include 2 RBs, and the frequency resource of the PSSCH may include n RBs. n may be a natural number. n can be set through signaling. A subchannel may include n+2 RBs. When PSSCH is transmitted in multiple subchannels, two RBs belonging to the first subchannel can be used for transmission of PSCCH, and two RBs belonging to the remaining subchannel(s) can be used for transmission of PSSCH there is.

Referring to FIG. 15b, PSCCH resources and PSSCH resources may be set to be non-adjacent in the frequency domain based on the FDM method. In other words, PSSCH resources can be separated from PSCCH resources in the frequency domain. One PSCCH resource may include two RBs. PSCCH resources can be configured adjacently in the frequency domain. One PSSCH resource may include n RBs. PSSCH resources can be configured adjacently in the frequency domain. Each subchannel may include n RBs. The method of FIG. 15A (eg, adjacent PSCCH+PSSCH method) and the method of FIG. 15B (eg, non-adjacent PSCCH+PSSCH method) may each have advantages and disadvantages. The method of FIG. 15A or the method of FIG. 15B may be used depending on the communication system and/or surrounding circumstances.

For same-channel coexistence between the LTE SL terminal and the NR SL terminal, NR SL resources can be set considering LTE SL resource settings. For example, NR SL resources can be set to fit the LTE SL resource grid by considering the ratio between LTE SL SCS and NR SL SCS.

If the same SCS is used between two RATs (eg, LTE and NR), the size of the NR SL subchannel may be set to be the same as the size of the LTE SL subchannel. If the LTE SL resource settings are the same as the embodiment of FIG. 15A, the NR SL subchannel may be configured to include n+2 RBs. If the LTE SL resource settings are the same as the embodiment of FIG. 15b, the NR SL subchannel can be configured to include n RBs. Subchannels can be set to have an integer multiple relationship between the size of the NR SL subchannel and the size of the LTE SL subchannel. The size (eg, frequency resource size) of the first RAT subchannel may be an integer multiple of the size of the second RAT subchannel. If the first RAT is LTE (eg, LTE communication technology), the second RAT may be NR (eg, NR communication technology). If the first RAT is NR, the second RAT may be LTE. The size of the NR SL subchannel can be set to 1/2 of the size of the LTE SL subchannel. In this case, one LTE SL subchannel may include two NR SL subchannels. Alternatively, the size of the NR SL subchannel may be set to twice the size of the LTE SL subchannel. In this case, one NR SL subchannel may include two LTE SL subchannels. In addition to the above 2 times, various integer multiples may be applied in the present disclosure.

If the SCS is different between two RATs, the size of the NR SL subchannel can be set considering the ratio of SCS. LTE SL SCS may be 15kHz, and NR SL SCS may be 30kHz. In this case, the number of RBs included in the NR SL subchannel is the number of RBs included in the LTE SL subchannel so that the size of the NR SL subchannel (e.g., frequency resource size) is twice the size of the LTE SL subchannel. It can be set equal to the number. The ratio between LTE SL SCS (15kHz) and NR SL SCS (30kHz) may be 1/2. In this case, the number of RBs included in the NR SL subchannel is the number of RBs included in the LTE SL subchannel so that the size of the NR SL subchannel (e.g., frequency resource size) is the same as the size of the LTE SL subchannel. It can be set to 1/2 of . In addition to the SCS (eg, 15 kHz, 30 kHz), various SCSs may be applied in the present disclosure.

When the SCS between two RATs is the same, an integer multiple relationship can be formed between the first RAT subchannel and the second RAT subchannel. If the SCS between the two RATs is different, the size of the subchannel can be set considering the ratio between the first RAT SCS and the second RAT SCS. For example, the size of the NR SL subchannel may be set to an integer multiple of the size of the LTE SL subchannel. Alternatively, the size of the NR SL subchannel may be set to be the same as the size of the LTE SL subchannel. If the SL resource grid of the first RAT and the SL resource grid of the second RAT are aligned, complexity and/or ambiguity in the resource selection operation may be reduced. Additionally, the efficiency of resource use can be improved. “When the SL resource grid of the first RAT and the SL resource grid of the second RAT are aligned” may include “when an integer multiple relationship is formed between the first RAT subchannel and the second RAT subchannel.” When the LTE SL resource is configured based on the method of FIG. 15b (eg, non-contiguous PSCCH+PSSCH method), it may be desirable for the NR SL resource to be configured only in the resource area of the PSSCH of the LTE SL.

Figure 16 is a conceptual diagram showing an example in which resource grids between LTE SL and NR SL are not aligned.

Referring to FIG. 16, even if the resource grids between the LTE SL and NR SL are not aligned, resource waste in case #1 may be relatively small. If the resource grids between LTE SL and NR SL are not aligned, the number of NR SL resources that cannot be used due to use of LTE SL resources in case #2 may be large. The resource waste in case #2 may be greater than the resource waste in case #1. Regardless of the SCS between two RATs, resource waste is reduced if “the NR SL resource grid remains the same as the LTE SL resource grid” or “if an integer multiple relationship is formed between the NR SL resource grid and the LTE SL resource grid” It can be done, and efficient use of resources can be possible.

The size of the LTE SL subchannel can be set to 4, 5, 6, 8, 9, 10, 12, 15, 16, 18, 20, 25, 30, 48, or 50 RB. The size of the NR SL subchannel can be set to 10, 12, 15, 20, 25, 50, 75, or 100 RB. For alignment of resource grids between two RATs, it may be desirable for an integer multiple relationship to be formed between the NR SL resource grid and the LTE SL resource grid. Since the size of the LTE SL subchannel may be different from the size of the NR SL subchannel, it may be difficult to set the NR SL subchannel to have an integer multiple relationship with the size of the LTE SL subchannel. To solve the above problem, it may be desirable to add the size (eg, number of RBs) of configurable NR SL subchannels. For example, the size of existing NR SL subchannels (e.g., 10, 12, 15, 20, 25, 50, 75, or 100 RBs) as well as the size of new NR SL subchannels (e.g., 4, 5, 6, 8, 9, 16, 18, 30, and/or 48 RBs) may be used. In other words, 4, 5, 6, 8, 9, 16, 18, 30, and/or 48 RBs can be added to the size of the NR SL subchannel.

According to the above method, the NR SL subchannel can be set to various sizes. In this case, the complexity of NR SL communication (e.g., NR SL system) may increase, and coexistence issues with existing NR SL terminals may occur. Therefore, it may be desirable to reduce the number of new NR SL subchannels added. “If the LTE SL subchannel includes 5 RBs and the NR SL subchannel includes 10 RBs”, an integer multiple relationship can be formed between the LTE SL subchannel and the NR SL subchannel. Among the sizes of the new NR SL subchannels added, size(s) that have an integer multiple relationship with the size of the LTE SL subchannel may be excluded. The sizes of new NR SL subchannels added may be limited to 8, 9, 16, 18, 30, and/or 48 RBs. Additionally, among the sizes of the new NR SL subchannels added, size(s) with an integer multiple relationship may be excluded. For example, 16 is a multiple of 8 and 18 is a multiple of 9, so instead of 8 and 9 RBs, 16 and 18 RBs can be added as the size of the new NR SL subchannel.

Subchannel sizes of less than or equal to 10 RBs may not be supported in existing NR SL systems. As in the embodiment of FIG. 12, the multiplexing method of PSCCH/PSSCH in the NR SL system may be different from the multiplexing method of PSCCH/PSSCH in the LTE SL system. Considering the above-described situations, it may not be desirable to add less than 10 RBs or fewer RBs to the size of the new NR SL subchannel. Therefore, it may be desirable to limit the sizes of new NR SL subchannels added to 16, 18, 30, and/or 48 RBs. Alternatively, “if the subchannel size is 18RBs or 48RBs and the PSCCH size of the LTE SL system is 2RBs”, the subchannel size may be 20RBs or 50RBs. 20RBs and 50RBs may be subchannel sizes supported by the NR SL system. Therefore, it may be desirable to limit the sizes of added new NR SL subchannels to 16 and/or 30 RBs.

If the resource grids between two RATs in the embodiment of FIG. 16 are not aligned, resource waste may occur. Additional methods are needed to reduce this resource waste. In a resource selection operation, the RSRP for a resource determined to be used by another terminal may be measured, and if the measured RSRP is greater than or equal to the RPRP threshold, the resource may be excluded from the candidate resources. If the LTE SL subchannel determined to be used by another terminal partially overlaps with the NR SL subchannel, RSRP for the overlapping resource area can be measured, and the total size of the NR SL subchannel can be added to the measured RSRP. Considered scaling can be applied, and if the scaled RSRP is more than the RSRP threshold, the corresponding resource (eg, NR SL subchannel) can be excluded from the candidate resource. Alternatively, when the LTE SL subchannel determined to be used by another terminal partially overlaps with the NR SL subchannel, RSRP for the entire resource area of the NR SL subchannel can be measured, and the measured RSRP is If the RSRP threshold is higher, the corresponding resource (eg, NR SL subchannel) may be excluded from the candidate resource. Reference signals may not exist in the remaining resource areas other than the overlapping resource areas. Therefore, RSSI can be used instead of RSRP.

Even when “the resource grids (e.g., frequency resource grids) between two RATs are aligned” or “when an integer multiple relationship is formed between the subchannel size of the first RAT and the subchannel size of the second RAT” , If the SCSs between two RATs are different, appropriate resource selection operation considering the different SCSs may be necessary. The size of resources excluded from the NR SL resource selection operation according to the LTE SL sensing result can be set. In this case, NR SL subchannel(s) corresponding to an area overlapping with LTE SL resources (eg, LTE SL sensing results) in the frequency domain may be selected. The number of slots excluded in the time domain can be determined considering the ratio of SCSs between two RATs (eg, SCS _NR / SCS _LTE ). For example, “if the LTE SL SCS is 15kHz and the NR SL SCS is 30kHz”, the ratio between the SCSs may be 2 (=30kHz/15kHz). In this case, two NR SL slots corresponding to one LTE SL slot may be excluded from the resource selection operation.

[Data transmission method considering AGC issues in a coexistence environment between LTE SL terminal and NR SL terminal]

Even in operations other than resource selection operations, the relationship between LTE subframes and NR slots in the time domain needs to be considered according to the SCSs between two RATs. “If NR SCS is 30kHz and LTE SCS is 15kHz”, two NR slots may exist within one LTE subframe. “If the AGC operation is performed based on an LTE subframe, and the received powers for the two NR slots included in the LTE subframe are different from each other, problems may occur in the AGC operation.”

Figure 17 is a conceptual diagram showing a first embodiment of NR transmission using different transmission powers.

Referring to FIG. 17, LTE SCS may be 15kHz, and NR SCS may be 30kHz. One LTE subframe may include two NR slots. LTE transmission (LTE TX) in an LTE subframe and NR transmissions (NR TX #1 and NR TX #2) in NR slots can be performed simultaneously. The terminal can perform AGC operation based on the LTE subframe. If the difference between the transmit power (e.g., received power) of NR TX #1 in the first NR slot and the transmit power (e.g., received power) of NR TX #2 in the second NR slot is large, the LTE subframe During reception, deterioration of reception performance may occur due to changes in reception power. In “when one of two NR slots is not transmitted” or “when PSFCH is transmitted in the NR slot”, the change in transmission power is large, so the deterioration in reception performance may be significant. To solve the above problem, SCS for NR slots coexisting with LTE subframes may always be limited to 15kHz. If the same SCS (eg, 15 kHz SCS) is applied to the NR slot and the LTE subframe, one NR slot may exist in one LTE subframe. Therefore, the AGC problem caused by changes in received power in NR slots can be solved.

Different SCSs can be applied to NR slots and LTE subframes. In this case, the NR SL resources used by the NR terminal (e.g., NR SL terminal) for SL transmission in the time domain may overlap with the LTE SL resources, and the NR resources used by the NR terminal (e.g., NR SL terminal) for SL transmission in the frequency domain SL resources may not overlap with LTE SL resources. In the above situation, the terminal can perform SL transmission using NR SL resources in a plurality of NR slots. “Difference between the transmit power of NR TX #1 and the transmit power of NR TX #2”, “Omission of transmission in at least one NR slot of the NR slots”, or “Transmission of PSFCH in at least one of the NR slots To solve the AGC issue arising from ", the NR terminal can always perform SL transmission in two slots.

The number of NR slots (N _slot ) in which SL transmission is continuously performed can be set in consideration of the ratio between LTE SCS and NR SCS (for example, N _slot = SCS _NR / SCS _LTE ). When NR SL resources overlap with LTE SL resources, the NR terminal can perform SL transmission in N _slots . If NR SL resources do not overlap with LTE SL resources, the NR terminal can perform SL transmission in one slot or less than N _slots . When SL transmission is performed in N consecutive _slots , AGC issues may temporarily occur due to guard symbols present in the slots. When SL transmission is performed in consecutive N _slots , it may be desirable to repeat the previous PSSCH transmission in guard symbols present in the slots. When SL transmission is performed in N consecutive N _slots , the receiving terminals for the N consecutive N _slots may be the same or different. The receiving terminal for consecutive N _slots can be determined according to transmission power when performing SL transmission. When a power control operation based on SL pathloss is performed, it may be desirable for the receiving terminal for N consecutive _slots in which SL transmission is performed to be the same. “If the receiving terminals for consecutive N _slots are different from each other, and the difference in transmission power between the slots is large due to the SL path loss-based power control operation,” the slots (e.g., N consecutive _slots AGC issues for the receiving terminal may occur in the LTE subframe corresponding to (slots).

When a power control operation based on SL path loss is performed, in order to solve the AGC issue, the transmitting terminal can perform SL transmission for the same receiving terminal in N consecutive _slots . “If a power control operation based on SL path loss is performed and the difference in transmission power for different terminals is not large,” the transmitting terminal transmits SL to different receiving terminals in N consecutive _slots . It can be done. For example, when the difference between the first transmission power of the first receiving terminal and the second transmission power of the second receiving terminal is less than a certain value, the transmitting terminal transmits the first receiving terminal and the second receiving terminal in N consecutive _slots . SL transmission to the terminal can be performed. The specific value may be set in the terminal through signaling (e.g., signaling of system information, PC5-RRC signaling, UE-specific RRC signaling, signaling of MAC CE, signaling of control information). The specific value may be set in units of resource pool. Alternatively, the terminal may determine a specific value by implementation.

“If the transmitting terminal performs a power control operation based on DL path loss” or “The transmitting terminal performs SL transmission using the maximum transmission power without performing a power control operation based on DL path loss (or SL path loss)” In this case, SL transmission in N consecutive _slots can always be performed using the same transmission power regardless of the receiving terminal. Therefore, SL transmission can be performed without restrictions on the same receiving terminal.

When SL transmission is performed in N consecutive _slots , it may be desirable for the frequency resource size of each slot to be the same in the frequency domain. If the receiving terminal, size of transmitted data, MCS level, and/or priority are different in each slot, the size of resources required for SL transmission may be different. Therefore, it may be difficult for N _slots in a row to have the same size of frequency resources. In this case, data (e.g., SL data) transmitted in the first slot among the consecutive N _slots may be repeatedly transmitted in the remaining slot(s) after the first slot. The receiving terminal can know in advance that data is repeatedly transmitted in N consecutive _slots . In this case, the receiving terminal can repeatedly receive data in N consecutive _slots , and reception performance can be improved by repeated reception of data.

If data reception is successful in the first slot among the consecutive N _slots , the receiving terminal can implementally determine whether repeated data is received in the remaining slot(s) after the first slot. To support the above operation, whether data is repeatedly transmitted in N consecutive _slots may be signaled to the terminal. For example, information indicating whether data is repeatedly transmitted in N consecutive _slots may be included in the SCI (eg, first-stage SCI and/or second-stage SCI).

Alternatively, the transmitting terminal may transmit actual data in the first slot among N consecutive _slots and transmit dummy signals in the remaining slot(s). The receiving terminal may perform a reception operation for actual data in the first slot among the consecutive N _slots and may omit the reception operation in the remaining slot(s). To support the above operation, the transmitting terminal may signal information indicating whether to transmit a dummy signal to the receiving terminal. Information indicating whether to transmit a dummy signal in the remaining _slot (s) except the first slot among the consecutive N slots may be included in the SCI (e.g., first stage SCI and/or second stage SCI). there is.

“Information indicating whether to transmit data repeatedly in N consecutive _slots ” or “Information indicating whether to transmit a dummy signal in the remaining _slot (s) except the first slot among N consecutive slots.” can be dynamically signaled by SCI. The size of “information indicating whether data is repeatedly transmitted in N consecutive _slots ” or “information indicating whether a dummy signal is transmitted” may be 1 bit. In other words, “information indicating whether data is repeatedly transmitted in N consecutive _slots ” or “information indicating whether a dummy signal is transmitted” may be an indicator with a size of 1 bit, and the indicator is in the SCI. It can be explicitly signaled. In another way, the specific value of a specific field included in the SCI implicitly indicates “information indicating whether to transmit data repeatedly in N consecutive _slots ” or “information indicating whether to transmit a dummy signal.” You can.

Considering one or more conditions (e.g., transmission power, TB size, MCS level, receiving terminal) for SL transmission in consecutive N _slots , the transmitting terminal can transmit different receiving terminals or the same in each slot. Different data can be transmitted to the receiving terminal. Alternatively, the transmitting terminal may repeatedly transmit data to the same receiving terminal in N consecutive _slots . Alternatively, the transmitting terminal may transmit data in some slots (eg, the first slot) among the N consecutive _slots and transmit a dummy signal in the remaining slot(s). The receiving terminal can receive data in the first slot among N consecutive _slots . Afterwards, the receiving terminal may perform a receiving operation by considering the transmission method indicated by the transmitting terminal in the remaining slot(s) other than the first slot among the consecutive N _slots . “If the same data is transmitted repeatedly in N consecutive _slots , and the receiving terminal successfully receives data in the first slot among the N consecutive _slots ,” the receiving terminal is transmitted in the N consecutive _slots . The reception operation can be omitted in the remaining slot(s) except for the first slot.

“If the same data is transmitted repeatedly in N consecutive N _slots , and the receiving terminal fails to receive data in the first slot among the N consecutive N _slots ,” the receiving terminal is transmitted among the N consecutive N _slots . A reception operation for data can be performed in the remaining slot(s) after the first slot. The receiving terminal can improve reception performance by performing a combining operation on data received in slots.

When a dummy signal is transmitted in the remaining _slot (s) except the first slot among the consecutive N slots, the receiving terminal performs a reception operation in the remaining _slot (s) except the first slot among the consecutive N slots. can be omitted. “If data is not transmitted repeatedly in N consecutive _slots ” or “If a dummy signal is not transmitted in the remaining _slot (s) except the first slot among N consecutive slots,” the receiving terminal Even after data is successfully received in the first slot among N consecutive _slots , a reception operation for data can be performed in the remaining slot(s) after the first slot.

Therefore, “information indicating whether to transmit data repeatedly in N consecutive _slots ” or “information indicating whether to transmit a dummy signal in the remaining _slot (s) except the first slot among the consecutive N slots. " may be preferably signaled to the terminal by SCI (e.g., a 1-bit indicator included in SCI).

"Repeated transmission of data in N consecutive N _slots ", "Transmission of different data in N consecutive N _slots ", or "Transmission of a dummy signal in some of the N consecutive N _slots " means It can be performed depending on the situation. In order to dynamically indicate the transmissions, an indication field with a size of 2 bits or more within the SCI may be required. Alternatively, information indicating whether to apply each of the transmissions may be set in the terminal through signaling (e.g., system information signaling, PC5-RRC signaling, UE-specific RRC signaling). Information indicating whether to apply each of the transmissions may be set in units of resource pools.

In order to solve the AGC problem between the LTE subframe and the NR slot, NR SL resource(s) corresponding to the transmission point (e.g., transmission time, transmission duration) of the LTE terminal are LTE SL resources of the LTE terminal in the frequency domain. Even if it does not overlap with (s), the NR SL resource(s) may be excluded from the NR SL resource selection operation. The NR SL module can receive LTE SL information from the LTE SL module and perform an NR SL resource selection operation based on the LTE SL information. Even if the NR SL resource(s) corresponding to the transmission time for the LTE SL resource(s) used by the LTE SL module do not overlap with the LTE SL resource(s) in the frequency domain, the NR SL module Resource(s) may be excluded from the NR SL resource selection operation. If there are many LTE SL resources (eg, resources that the LTE terminal wants to use), the NR SL module may not secure sufficient candidate resources in the NR SL resource selection operation.

“If the LTE SCS is 15kHz and the NR SCS is 30kHz”, one LTE subframe may include two NR slots. When the start point of the first NR slot of the two NR slots (e.g., the start point of the first OFDM symbol) overlaps the start point of the LTE subframe (e.g., the start point of the first OFDM symbol) , AGC problems may not occur even if SL transmission is not performed in the second NR slot. In other words, AGC operation considering the transmission power (or reception power) for the NR slot can be performed from the start of the LTE subframe. Therefore, even if SL transmission is not performed in the second NR slot, AGC operation may be possible within the allowable range.

The start time of the LTE subframe may not overlap with the start time of the NR slot. For example, if the resources of the first NR slot are empty, the start time of the LTE subframe may not overlap with the start time of the NR slot. In this case, AGC operation for the LTE subframe can be performed without considering the transmission power of the NR slot. If SL transmission in the second NR slot is performed based on high transmission power, the AGC allowable range may be exceeded from the start of the second NR slot. Therefore, saturation may occur and reception performance may deteriorate. Transmission duration for LTE SL (e.g., LTE SL resource) only if the start time of the LTE subframe does not overlap with the start time of the NR slot (e.g., the resource of the first NR slot is empty) If the NR SL resource(s) corresponding to (duration) are excluded from the NR SL candidate resources, the problem of not obtaining sufficient NR SL candidate resources can be solved.

A proposed method to solve the AGC problem between LTE subframes and NR slots (e.g., SL transmission in multiple NR slots, exclusion of LTE SL resources, transmission for LTE SL (e.g., LTE SL resources) Exclusion of NR SL resource(s) corresponding to duration) may be applied differently depending on various environments. For example, in an environment where there is not much LTE SL traffic, the transmitting terminal can secure sufficient NR SL candidate resources even when NR SL resources corresponding to the start time for LTE SL resources are excluded. Exclusion of LTE SL resources may mean exclusion of NR SL resource(s) corresponding to the transmission duration for LTE SL (eg, LTE SL resource). In an environment where it is difficult to exclude LTE SL resources (eg, NR SL resources that overlap with LTE SL resources), the transmitting terminal can perform SL transmission in a plurality of NR slots. Alternatively, in an environment where it is difficult to exclude LTE SL resources (e.g., NR SL resources overlapping with LTE SL resources), if the frequency resources of the LTE subframe do not overlap with the frequency resources of the NR slot, the LTE subframe SL transmission may be allowed in NR slots that overlap with the start time. According to the above methods, the AGC problem between LTE subframes and NR slots can be solved. Information indicating the application of “SL transmission operation in multiple NR slots” and “LTE SL resource exclusion operation” may be set for each resource pool or BWP. Information indicating the application of each of the “SL transmission operation in a plurality of NR slots” and “exclusion operation of LTE SL resources” includes signaling (e.g., signaling of system information, UE-specific RRC signaling, PC5-RRC signaling, It can be set in the terminal through MAC CE signaling).

[PSFCH transmission method considering AGC issues in a coexistence environment between LTE SL terminal and NR SL terminal]

SL transmission can be performed in N consecutive _slots considering LTE SL SCS and NR SL SCS. In this case, if there is an NR slot in which PSFCH resources are configured, “the difference between the transmission power in the PSFCH resource and the transmission power in resources other than the PSFCH resource (e.g., PSCCH resource and/or PSSCH resource)” and/or “PSSCH symbol AGC issues may occur due to the “guard symbol between the and PSFCH symbols.” If PSFCH resources are not configured in N consecutive N _slots , it may be desirable to perform SL transmission in N consecutive N _slots . If PSFCH resources are configured in the NR slot, a transmission method considering PSFCH resources may be necessary.

In NR SL, PSFCH may be a channel for transmission of HARQ-ACK feedback (eg, ACK or NACK) for PSSCH. PSFCH can only exist in the NR slot. In other words, PSFCH may not exist in an LTE subframe. When an NR slot and an LTE subframe overlap, all symbols in the LTE subframe can be used for data transmission, and some symbols in the NR slot can be set as PSFCH symbols and AGC symbols for the PSFCH. Therefore, it may be desirable to set the resource areas between two RATs in the PSFCH symbol and/or AGC symbol so that they do not overlap. This is a method of setting the resource areas between two RATs in the PSFCH resource area so that they do not overlap. The resource area corresponding to the NR slot through which the PSFCH is transmitted (e.g., the NR slot containing the PSFCH symbol) is used only by the NR terminal. It can be set to be used. An LTE subframe may also be set in a resource area corresponding to an NR slot in which PSFCH is not transmitted, and the resource area (e.g., NR slot, LTE subframe) may be used by both an NR terminal and an LTE terminal. According to the above method, overlapping between resource areas between two RATs in the PSFCH resource area can be prevented.

A PSFCH slot (eg, an NR slot through which PSFCH is transmitted) may be set to a period of 1, 2, or 4 slots. When the PSFCH slot period is 1 slot, all slots can be set to NR slots. In this case, LTE SL transmission may not be performed. If the LTE SCS and NR SCS are different, a situation in which setting an LTE subframe is difficult may occur. For example, if “LTE SCS is 15kHz, NR SCS is 30kHz, and the PSFCH slot period is 2 slots,” setting up an LTE subframe may be difficult. If NR resources are set after LTE resources are set, updating LTE resources may be difficult. It may be difficult to configure the PSFCH slot only for NR terminals.

As another method of configuring the PSFCH resource area so that the resource areas between two RATs do not overlap, the frequency resource area of the PSFCH may be set so as not to overlap with the resource area of the LTE SL (e.g., frequency resource area). When an LTE terminal and an NR terminal coexist on the same channel, the frequency resource area of PSFCH may be set so as not to overlap with the resource area of LTE SL. In this case, the SL transmission of the LTE terminal can be prevented from overlapping with the PSFCH transmission. The frequency resource area of PSFCH can be set within a resource pool and can be indicated by a bitmap. Each bit in the bitmap may correspond to n RBs. n may be a natural number. PSFCH can be set in a resource area that does not overlap with the resource area of LTE SL.

FIG. 18A is a first embodiment showing PSFCH resource allocation, and FIG. 18B is a second embodiment showing PSFCH resource allocation.

Referring to Figure 18a, PSFCH resources may overlap with LTE resources. Referring to FIG. 18b, PSFCH resources may be set in consideration of LTE resources, and PSFCH resources may not overlap with LTE resources. In an environment where an LTE terminal and an NR terminal coexist on the same channel, PSFCH resources can be set so as not to overlap with LTE resources, as in the embodiment of FIG. 18B. In this case, collisions between PSFCH transmission and LTE SL transmission can be prevented. Even if PSFCH resources are set to not overlap with LTE resources in the frequency domain, PSFCH transmission may overlap with LTE SL transmission in the time domain. In this case, transmission power may temporarily increase in the PSFCH transmission section, and AGC problems may occur in a terminal performing a reception operation in the PSFCH transmission section.

When reception operations for NR SL and LTE SL are performed simultaneously, transmission power may temporarily increase in the PSFCH transmission section, and the increased transmission power may be outside the AGC allowable range. In this case, reception performance may deteriorate. In an environment where an LTE terminal and an NR terminal coexist, it can be configured to perform a power control operation when transmitting PSFCH. If the terminal is within the coverage of the network, the existing power control operation for PSFCH may be set to be performed based on DL path loss (or SL path loss). If the terminal is outside the coverage of the network, PSFCH may be transmitted at maximum transmission power (P _max ).

In an environment where an LTE terminal and an NR terminal coexist on the same channel, the operation of the terminal outside the network coverage can generally be considered. Therefore, according to the existing standard, PSFCH can always be transmitted at maximum transmission power. To solve the above problem, a power control operation based on DL path loss (or SL path loss) can be set to be performed even outside of network coverage. Alternatively, it may be desirable to set the maximum transmission power to a value smaller than the existing value.

As another way to solve the coexistence problem of the same channel between the LTE terminal and the NR terminal for the PSFCH slot, the HARQ-ACK feedback function for the NR terminal that communicates on the same channel as the LTE terminal can be disabled. In other words, it can be set so that PSFCH transmission does not occur. In NR SL, unicast communication and groupcast communication can support the HARQ-ACK feedback function. The HARQ-ACK feedback function can be enabled or disabled. If resources for PSFCH transmission are not set in the resource pool, the HARQ-ACK feedback function may be determined to be disabled in the resource pool. When resources for PSFCH transmission are set in the resource pool, the transmitting terminal may transmit a second stage SCI including information indicating enabling or disabling the HARQ-ACK feedback function.

When an LTE terminal and an NR terminal coexist on the same channel, PSFCH resources may not be set in the resource pool so that PSFCH transmission does not occur. “If it is determined that the LTE terminal and the NR terminal coexist on the same channel, PSFCH resources are configured in the resource pool, and LTE SL transmission occurs in the PSFCH slot,” the NR terminal instructs disabling the HARQ-ACK feedback function. Information can be transmitted. Alternatively, if it is determined that LTE SL transmission occurs in a PSFCH slot (e.g., PSFCH symbol) in which HARQ-ACK feedback for data transmitted in a specific slot is transmitted, the NR terminal (e.g., transmitting terminal) can transmit data in slots other than the specific slot. If it is determined that LTE SL transmission occurs in a PSFCH slot (e.g., PSFCH symbol) where HARQ-ACK feedback for data is transmitted, the NR terminal (e.g., receiving terminal) drops transmission of HARQ-ACK feedback. You can (drop).

If PSFCH transmission is dropped, the transmitting terminal may not receive HARQ-ACK feedback for data from the receiving terminal. In the HARQ ACK/NACK feedback method for unicast, the transmitting terminal may determine that HARQ-ACK feedback has not been received as NACK and may retransmit the data. In HARQ ACK/NACK feedback option 2 for groupcast, the transmitting terminal may determine that HARQ-ACK feedback has not been received as NACK and may perform retransmission of the data. If the PSFCH transmission dropped by the receiving terminal is ACK, resources may be wasted due to data retransmission, but problems with data transmission and reception may not occur.

In HARQ ACK/NACK feedback option 1 for groupcast (e.g., NACK-only feedback method), ACK may not be transmitted if reception of data is successful, and NACK may be transmitted if reception of data fails. there is. If HARQ ACK/NACK feedback option 1 for groupcast is used, problems may occur in data transmission and reception operations. For example, if the receiving terminal fails to receive data, HARQ-ACK feedback may be NACK. In this case, if the receiving terminal drops the PSFCH transmission due to a collision with the LTE SL transmission, the transmitting terminal may determine that data reception at the receiving terminal was successful. Therefore, the transmitting terminal may not retransmit data.

To solve the above problem, when the PSFCH transmission is predicted to be dropped due to overlap between PSFCH transmission and LTE SL transmission, the transmitting terminal may transmit information indicating disabling of the HARQ-ACK feedback function to the receiving terminal. , the data can be retransmitted regardless of whether the data is received at the receiving terminal. In the data retransmission procedure, the HARQ-ACK feedback function can be continuously disabled, and the transmitting terminal can retransmit data a predefined number of times. Alternatively, if PSFCH transmission is possible, the transmitting terminal may transmit information indicating enabling of the HARQ-ACK feedback function to the receiving terminal and then retransmit the data. The transmitting terminal may receive HARQ-ACK feedback for retransmission data from the receiving terminal, and determine whether to perform a data retransmission procedure based on the HARQ-ACK feedback.

The method (eg, a method for preventing collisions between PSFCH transmission and LTE SL transmission) can be applied to all NR SL transmissions. Alternatively, the method may be applied only to some NR transmissions depending on conditions. The method may be “a method of selecting a slot in which data is transmitted considering the collision between PSFCH transmission and LTE SL transmission” and/or “a method of dropping the PSFCH transmission by considering the collision between PSFCH transmission and LTE SL transmission.” there is. The above method may not be applied to PSFCH transmission that satisfies certain condition(s). For example, the specific condition(s) are “when NR SL transmission with high priority is performed,” “when PSFCH resources overlap with LTE SL resources with low RSRP,” and/or “when overlapping with PSFCH slots.” It may include "a case where PSCCH and/or PSSCH having the same transmission power as PSFCH is transmitted in the time interval where the Specific condition(s) can be set per resource pool or BWP. Specific condition(s) may be set in the terminal by signaling (e.g., signaling of system information, UE-specific RRC signaling, PC5-RRC signaling, signaling of MAC CE, signaling of control information).

When PSFCH transmission is performed based on the existing procedure in NR SL, the PSFCH slot of NR SL may be excluded from the resource sensing operation of the LTE terminal. Unlike the resource sensing operation of the NR terminal, the LTE terminal may perform a selection operation of a candidate resource based on SCI and/or RSRP measurement, and select a final candidate based on the RSSI for the candidate resource(s) selected by the selection operation. You can choose resources. In other words, the LTE terminal may perform a first resource selection operation to select a candidate resource and a second resource selection operation to select a final candidate resource. In the resource selection operation(s), the LTE terminal may preferentially select a resource with low RSSI as the final candidate resource. The RSSI for the resource on which the PSFCH is transmitted (eg, PSFCH resource) may be measured relatively high. Therefore, the LTE terminal may exclude PSFCH resources from candidate resources (eg, final candidate resources) in resource selection operation(s).

To increase the probability of being excluded from the RSSI-based resource selection operation, some slots among SL resources may be set as basic slots (eg, basic PSFCH slot or basic resource set). It may be desirable for “PSCCH transmission” and/or “PSFCH transmission including PSSCH” to be transmitted in a basic slot. It may be desirable to select a resource for transmission of data associated with the HARQ-ACK feedback in the resource selection operation of the NR terminal so that the HARQ-ACK feedback is transmitted in a basic slot (e.g., a basic PSFCH slot). PSFCH slot(s) other than the basic PSFCH slot may be configured, and HARQ-ACK feedback may be transmitted in the PSFCH slot(s). In this case, AGC issues may occur in the LTE terminal (eg, LTE SL terminal), and resource conflicts may occur between the NR terminal and the LTE terminal. It may be desirable for the NR terminal's resource selection operation to operate such that PSFCH transmission occurs in the default PSFCH slot.

When PSFCH transmission increases in the NR terminal, resources for PSFCH transmission can be increased through additional configuration of the basic PSFCH slot. Performing RSSI measurement operations for the added basic PSFCH slot may not be initially excluded from the LTE terminal. In other words, the added basic PSFCH slot may not be excluded from the resource selection operation of the LTE terminal. The average RSSI may increase over time, and the probability that the added basic PSFCH slot will be excluded in the resource selection operation may gradually increase.

An LTE terminal that supports only periodic data transmission can perform RSSI measurement operations according to the reservation period of data resources. For example, the LTE terminal may perform RSSI measurement operations according to a period of 20ms, 50ms, or 100ms. It may be desirable for the basic PSFCH slot to be set in consideration of the period of the LTE terminal's RSSI measurement operation. Considering all reservation cycles of data resources in the LTE terminal, the period of RSSI measurement operation can be set to a period of 10ms (e.g., the greatest common divisor of all reservation periods) or 100ms (e.g., the least common multiple of all reservation periods). You can. To ensure that the RSSI for PSFCH transmission is measured to be high, the NR terminal can perform PSFCH transmission using maximum transmission power. In other words, PSFCH transmission using maximum transmission power can be configured in the terminal. The PSFCH transmission can be implemented implementation-wise. Alternatively, the PSFCH transmission may be predefined in technical specifications.

In order to solve the problem of coexistence of the same channel between the LTE terminal and the NR terminal in the PSFCH slot, the NR transmitting terminal sets a Resources can be selected first. In this case, the efficiency of resource selection may be reduced. In "when the NR transmitting terminal disables the HARQ-ACK feedback function" or "when the NR receiving terminal drops PSFCH transmission", the reliability of SL communication may be degraded and unnecessary retransmission operations may be performed. there is.

When the LTE terminal excludes the NR terminal's PSFCH resource (e.g., basic PSFCH slot) from the candidate resource (e.g., final candidate resource) based on RSSI, if the data traffic in the channel is high, the PSFCH resource is selected as a candidate resource. Exclusion from may not be guaranteed. Since the resource exclusion operation based on RSSI measurements is performed on candidate resources selected based on SCI and RSRP measurements, the selected final candidate resources may not be sufficient for transmission. Additionally, distorted final candidate resources may be selected. “A method for an NR transmitting terminal to select resources for transmission of data so that the PSFCH resource for HARQ-ACK feedback for data does not overlap with the SL resource of the LTE terminal”, “The NR transmitting terminal uses the HARQ-ACK feedback function “Method for disabling”, “Method for NR receiving terminal to drop PSFCH transmission”, and “Method for LTE terminal to exclude PSFCH resource of NR terminal from candidate resources (e.g., final candidate resource) based on RSSI” Depending on the situation, it may be desirable to use it appropriately.

In a “general situation” or “a situation in which channel data traffic is high”, “the NR transmitting terminal provides resources for transmission of the data so that the PSFCH resource for HARQ-ACK feedback for data does not overlap with the SL resource of the LTE terminal.” At least one of “a method for selecting”, “a method for the NR transmitting terminal to disable the HARQ-ACK feedback function”, or “a method for the NR receiving terminal to drop PSFCH transmission” may be applied. In a situation where the ratio of LTE terminals in the channel is low, the “method for the LTE terminal to exclude the PSFCH resource of the NR terminal from candidate resources (e.g., final candidate resources) based on RSSI” can be applied. The application method can be set in the terminal by signaling (e.g., signaling of system information, UE-specific RRC signaling, PC5-RRC signaling, signaling of MAC CE, signaling of control information). The application method can be set in units of resource pools. The terminal may determine the application method based on the success of the data transmission/reception operation and/or the result of the resource sensing operation, and may apply an SCI (e.g., first stage SCI and/or SCI) including information indicating the application method. Alternatively, a second stage SCI) may be transmitted.

[How to set a timeline to use LTE SL information]

One terminal may include an LTE SL module and an NR SL module. The point in time at which the sensing information of the LTE SL module (eg, the result of a resource sensing operation) is transmitted to the NR SL module may be before the time when the resource selection operation of the NR SL module is performed. Sensing information of the LTE SL module may be referred to as LTE sensing information or LTE sensing results. If the transmission time of the LTE sensing information is too far ahead of the performance time of the resource selection operation of the NR SL module, the LTE sensing information may be useless information at the time of performing the resource selection operation of the NR SL module. It may be desirable to appropriately set the transmission point of LTE sensing information.

Referring to FIG. 13, the NR SL resource selection operation may be triggered at n. In this case, the LTE sensing information required for the NR SL resource sensing operation may be delivered at n or before n. To prevent LTE sensing information from becoming useless information, restrictions on time points before n may be necessary. For example, it may be desirable for LTE sensing information to be transmitted between nT _s1 and n. T _s1 can be predefined as a fixed value. Alternatively, T _s1 may be set in the terminal by signaling (e.g., signaling of system information, UE-specific RRC signaling, PC5-RRC signaling, signaling of MAC CE, signaling of control information). T _s1 may be the same as T _proc,0 in FIG. 13. If LTE sensing information is delivered before T _s1 (eg, T _proc,0 ), the LTE sensing information may be determined to be useless information, and the LTE sensing information may be ignored.

LTE sensing information may be delivered at a time after n. In this case, restrictions on time points after n may be necessary so that LTE sensing information is considered as much as possible in the resource selection operation. For example, it may be desirable for LTE sensing information to be transmitted between n and n+T _s2 . T _s2 can be predefined as a fixed value. Alternatively, T _s2 may be set in the terminal by signaling (e.g., signaling of system information, UE-specific RRC signaling, PC5-RRC signaling, signaling of MAC CE, signaling of control information). T _s2 may be the same as T ₁ in FIG. 13. Alternatively, LTE sensing information may be transmitted between time points before n (eg, T _s1 ) and time points after n (eg, T _s2 ). If the LTE SCS and NR SCS are different, T _s1 and T _s2 may be set based on the NR SCS.

Within one terminal, the time when the LTE sensing information of the LTE SL module is transmitted to the NR SL module may be before the time when the resource selection operation of the NR SL module is performed. Considering the processing time of the resource selection operation of the NR SL module, it may be desirable to appropriately set the transmission time of LTE sensing information. As in the embodiment of FIG. 13, when the NR SL resource selection operation is triggered at n, the LTE sensing information required for the NR SL resource selection operation may be delivered at a time point before n. Considering the processing time of the NR SL module, it may be desirable for LTE sensing information to be delivered before nT _s3 , which is a time point earlier than n. T _s3 can be predefined as a fixed value. Alternatively, T _s3 may be set in the terminal by signaling (e.g., signaling of system information, UE-specific RRC signaling, PC5-RRC signaling, signaling of MAC CE, signaling of control information). T _s3 may be implementationally limited to within a time point (for example, 4 ms) for exchanging priority information for the modules in coexistence between the LTE SL module and the NR SL module included in the same terminal. In other words, the terminal can implementally determine T _s3 to be a value within 4 ms.

In the above embodiment as well, in order to prevent the LTE sensing information from becoming useless information, it may be necessary to appropriately set the transmission time of the LTE sensing information. Only LTE sensing information transmitted after nT _s4 can be determined as valid information. LTE sensing information delivered after nT _s4 can be used in NR SL resource selection operation. T _s4 may be predefined as a fixed value in consideration of the sensing window of the LTE module and/or the resource reservation period supported in the LTE SL. Alternatively, T _s4 may be set in the terminal by signaling (e.g., signaling of system information, UE-specific RRC signaling, PC5-RRC signaling, signaling of MAC CE, signaling of control information). If T _s4 is not set, the terminal can determine T _s4 by implementation. If the LTE SCS and NR SCS are different, it may be desirable for T _s3 and T _s4 to be set based on the NR SCS.

Figure 19 is a conceptual diagram showing a first embodiment of a timeline for transmitting LTE sensing information to the NR SL module.

Referring to FIG. 19, the NR SL module can determine that the LTE sensing information received between nT _s4 and nT _s3 is valid information, and can perform a resource selection operation by considering the LTE sensing information. T _s3 may be preferably set to T _proc,0 <T _s3 ≤4ms. T _s4 may be preferably set to 0<T _s4 ≤4ms. T _s4 can be set to an appropriate time before T _s3 . T _s4 can be set within the sensing window. For example, T _s4 may be after nT ₀ within the sensing window. Alternatively, T _s4 may be set before the sensing window (eg, nT ₀ ). If T _s3 and/or T _s4 are not set, the terminal may determine T _s3 and/or T _s4 by implementation. LTE sensing information may be transmitted to the NR SL module according to the request of the NR SL module or under specific conditions. In this case, T _s4 can be set after the request time of the NR SL module or when a specific condition is satisfied.

[Resource selection operation using IUC (inter-UE coordination) information]

In NR SL, the IUC function can be supported. In this case, the first terminal may transmit information on preferred resources and/or non-preferred resources to the second terminal. The second terminal may perform a resource selection operation considering preferred resources and/or non-preferred resources. A preferred resource may refer to a preferred candidate resource and/or a set of preferred resources. A non-preferred resource may mean a non-preferred candidate resource and/or a set of non-preferred resources. When a resource conflict between terminals is predicted, the first terminal may transmit conflict prediction information (eg, conflict resource information) to the second terminal. Collision prediction information may be transmitted to a terminal in which a collision is predicted through PSFCH (eg, PSFCH for CI). The method used among the transmission method of preferred resource information/non-preferred resource information and the transmission method of collision prediction information may be set in advance. Preferred resource information/non-preferred resource information may mean at least one of preferred resource information or non-preferred resource information.

The IUC function can be used to improve reliability between NR terminals. Alternatively, the IUC function can be applied for same-channel coexistence between an LTE terminal and an NR terminal. When the transmission method of preferred resource information/non-preferred resource information is used, the terminal including the LTE SL module and the NR SL module receives the result of the LTE SL resource sensing operation (e.g., LTE sensing information) and the NR SL resource sensing operation. Based on the results (eg, NR sensing information), at least one of a preferred resource list or a non-preferred resource list may be generated. In other words, the first terminal may generate a preferred resource list and/or a non-preferred resource list by considering not only NR sensing information but also LTE sensing information, and transmit the preferred resource list and/or non-preferred resource list to the second terminal. . The second terminal may perform a resource selection operation by considering the preferred resource list and/or the non-preferred resource list. LTE resources and NR resources may not be distinguished in each of the preferred resource list and the non-preferred resource list. The preferred resource list may mean preferred resource information, and the non-preferred resource list may mean non-preferred resource information.

A message (eg, MAC CE, SCI) containing preferred resource information and/or non-preferred resource information may be received at the NR terminal. Therefore, it may be desirable for a message containing preferred resource information and/or non-preferred resource information to be transmitted to the NR terminal. The preferred resource information and/or non-preferred resource information may be utilized in the resource selection operation of some NR terminals that cannot perform the LTE SL resource sensing operation in a coexistence environment of the same channel between the LTE terminal and the NR terminal.

When the transmission method of collision prediction information is used, a terminal including the LTE SL module and the NR SL module can predict resource conflicts between the LTE terminal and the NR terminal as well as resource conflicts between the NR terminals. In this case, the terminal may transmit collision prediction information through PSFCH (eg, PSFCH for CI). Collision prediction information may include NR collision prediction information and LTE/NR collision prediction information. NR collision prediction information may be prediction information about resource collisions between NR terminals. LTE/NR collision prediction information may be prediction information about resource collisions between an LTE terminal and an NR terminal.

Existing LTE terminals may not be able to utilize collision prediction information. Therefore, it may be desirable for collision prediction information to be transmitted to the NR terminal. Collision prediction information can be utilized in the resource selection operation of some NR terminals that cannot perform the LTE SL resource sensing operation in a coexistence environment of the same channel between the LTE terminal and the NR terminal. Even when resource collisions between LTE terminals are predicted, the LTE terminal cannot utilize collision prediction information, so it may be desirable that prediction information about resource collisions between LTE terminals is not transmitted to the LTE terminal.

[Time synchronization method between LTE terminal and NR terminal]

For same-channel coexistence between an LTE terminal and an NR terminal, it may be necessary for LTE SL resources and NR SL resources to be well aligned in the time and/or frequency domain. If resources are not aligned in two RATs, performance may deteriorate due to interference in resource sensing operations, resource selection operations, and/or transmission operations. For alignment of resources in two RATs, obtaining accurate synchronization may be necessary. It can be important that motivation is achieved based on the same criteria.

In SL communication, depending on the setting and/or situation, the synchronization reference may be a global navigation satellite system (GNSS), a base station, and/or another terminal. The NR terminal may synchronize to an NR base station (eg, gNB) and/or LTE base station (eg, eNB). An LTE terminal can synchronize only to an LTE base station (eg, eNB). If the synchronization standard is a different terminal, the NR terminal can synchronize with other NR terminals and/or LTE terminals. An LTE terminal can only synchronize with other LTE terminals.

According to the selection criteria of the synchronization source, the priority of the LTE communication node (eg, LTE base station, LTE terminal) may be higher than the priority of the NR communication node (eg, NR base station, NR terminal). In this case, since the LTE terminal and the NR terminal obtain synchronization through the same synchronization source, problems may not occur. If the priority of an NR communication node (e.g., NR base station, NR terminal) is higher than the priority of an LTE communication node (e.g., LTE base station, LTE terminal), the NR terminal selects a synchronization source with high priority. However, the LTE terminal cannot select a synchronization source with high priority. In this case, the synchronization between two RTAs (for example, an NR terminal and an LTE terminal) may not be exactly synchronized. Therefore, the performance of resource sharing may deteriorate.

To solve the above problem, the NR terminal can transmit an LTE SL synchronization signal to the LTE terminal. If the priority of the NR communication node (e.g., NR base station, NR terminal) is higher than the priority of the LTE communication node (e.g., LTE base station, LTE terminal), the NR terminal is connected to the NR base station and/or another NR terminal. Synchronization can be obtained from, and an LTE SL synchronization signal can be transmitted to the LTE terminal based on the acquired synchronization. The LTE terminal can receive the LTE SL synchronization signal from the NR terminal and acquire synchronization based on the LTE SL synchronization signal. In this case, the NR terminal and the LTE terminal can operate based on the same synchronization.

The operation of the method according to the embodiment of the present disclosure can be implemented as a computer-readable program or code on a computer-readable recording medium. Computer-readable recording media include all types of recording devices that store information that can be read by a computer system. Additionally, computer-readable recording media can be distributed across networked computer systems so that computer-readable programs or codes can be stored and executed in a distributed manner.

Additionally, computer-readable recording media may include hardware devices specially configured to store and execute program instructions, such as ROM, RAM, or flash memory. Program instructions may include not only machine language code such as that created by a compiler, but also high-level language code that can be executed by a computer using an interpreter or the like.

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

In embodiments, a programmable logic device (e.g., a field programmable gate array) may be used to perform some or all of the functionality 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. In general, it is desirable for the methods to be performed by some hardware device.

Although the present disclosure has been described above with reference to preferred embodiments, those skilled in the art may modify and change the present disclosure in various ways without departing from the spirit and scope of the present disclosure as set forth in the claims below. You will understand that it is possible.

Claims (20)

A method of a first terminal supporting a first radio access technology (RAT) and a second RAT,
determining candidate resources by performing a first RAT-based resource sensing operation;
performing a first RAT-based resource selection operation for the candidate resources in consideration of second RAT resource information; and
Comprising the step of performing sidelink (SL) communication with a second terminal and a first RAT based on the resources selected by the resource selection operation.
Method of the first terminal. In claim 1,
When resource sharing between the first RAT and the second RAT is established, the second RAT resource information is shared in the first RAT-based resource selection operation, and the first RAT is a new radio (NR) communication technology, The second RAT is a long term evolution (LTE) communication technology,
Method of the first terminal. In claim 1,
The second RAT resource information indicates one or more resources reserved by a third terminal supporting the second RAT, and one or more resources reserved among the candidate resources in the first RAT-based resource selection operation. At least one candidate resource that overlaps is excluded,
Method of the first terminal. In claim 1,
"The second RAT resource information indicates one or more resources reserved by a third terminal supporting the second RAT, and reference signal received power (RSRP) of at least one resource reserved among the one or more reserved resources ) is more than the RSRP threshold", in the first RAT-based resource selection operation, at least one candidate resource that overlaps the reserved at least one resource among the candidate resources is excluded,
Method of the first terminal. In claim 1,
The second RAT resource information includes time resource information reserved by the third terminal, frequency resource information reserved by the third terminal, period information of the resource reserved by the third terminal, and RSRP for the reserved resource. Containing at least one of information, or priority information about data of the third terminal,
Method of the first terminal. In claim 4,
The RSRP threshold is set by system information, PC5-RRC (radio resource control) signaling, or UE (user equipment)-RRC signaling,
Method of the first terminal. In claim 1,
When the first subcarrier spacing (SCS) applied to the first RAT and the second SCS applied to the second RAT are different, the selected resources include resources that overlap with the timing of SL transmission based on the second RAT, The first RAT-based SL communication is performed continuously during the period of the second RAT-based SL transmission,
Method of the first terminal. In claim 1,
If the first SCS applied to the first RAT and the second SCS applied to the second RAT are different, the selected resources include a first slot overlapping with the timing of SL transmission based on the second RAT, and the first In the first slot, the first RAT-based SL communication is allowed,
Method of the first terminal. In claim 1,
In the first RAT-based SL communication between the first terminal and the second terminal, when the first RAT-based physical sidelink feedback channel (PSFCH) transmission overlaps with the second RAT-based SL transmission, the first RAT-based PSFCH transmission is dropped or disabled,
Method of the first terminal. In claim 1,
The step of performing the first RAT-based resource selection operation is:
When the first RAT-based PSFCH transmission overlaps with the second RAT-based SL transmission, at least one candidate for PSSCH (physical sidelink shared channel) transmission associated with the first RAT-based PSFCH transmission among the candidate resources Including the step of excluding resources,
Method of the first terminal. A first terminal supporting a first radio access technology (RAT) and a second RAT,
Contains a processor,
The processor is the first terminal,
Determine candidate resources by performing a first RAT-based resource sensing operation;
Perform a first RAT-based resource selection operation for the candidate resources in consideration of second RAT resource information; and
causing sidelink (SL) communication based on the second terminal and the first RAT to be performed using the resources selected by the resource selection operation,
1st terminal. In claim 11,
When resource sharing between the first RAT and the second RAT is established, the second RAT resource information is shared in the first RAT-based resource selection operation, and the first RAT is a new radio (NR) communication technology, The second RAT is a long term evolution (LTE) communication technology,
1st terminal. In claim 11,
The second RAT resource information indicates one or more resources reserved by a third terminal supporting the second RAT, and one or more resources reserved among the candidate resources in the first RAT-based resource selection operation. At least one candidate resource that overlaps is excluded,
1st terminal. In claim 11,
"The second RAT resource information indicates one or more resources reserved by a third terminal supporting the second RAT, and reference signal received power (RSRP) of at least one resource reserved among the one or more reserved resources ) is more than the RSRP threshold", in the first RAT-based resource selection operation, at least one candidate resource that overlaps the reserved at least one resource among the candidate resources is excluded,
1st terminal. In claim 11,
The second RAT resource information includes time resource information reserved by the third terminal, frequency resource information reserved by the third terminal, period information of the resource reserved by the third terminal, and RSRP for the reserved resource. Containing at least one of information, or priority information about data of the third terminal,
1st terminal. In claim 14,
The RSRP threshold is set by system information, PC5-RRC (radio resource control) signaling, or UE (user equipment)-RRC signaling,
1st terminal. In claim 11,
When the first subcarrier spacing (SCS) applied to the first RAT and the second SCS applied to the second RAT are different, the selected resources include resources that overlap with the timing of SL transmission based on the second RAT, The first RAT-based SL communication is performed continuously during the period of the second RAT-based SL transmission,
1st terminal. In claim 11,
If the first SCS applied to the first RAT and the second SCS applied to the second RAT are different, the selected resources include a first slot overlapping with the timing of SL transmission based on the second RAT, and the first In the first slot, the first RAT-based SL communication is allowed,
1st terminal. In claim 11,
In the first RAT-based SL communication between the first terminal and the second terminal, when the first RAT-based physical sidelink feedback channel (PSFCH) transmission overlaps with the second RAT-based SL transmission, the first RAT-based PSFCH transmission is dropped or disabled,
1st terminal. In claim 11,
When performing the first RAT-based resource selection operation, the processor allows the first terminal to:
When the first RAT-based PSFCH transmission overlaps with the second RAT-based SL transmission, at least one candidate for PSSCH (physical sidelink shared channel) transmission associated with the first RAT-based PSFCH transmission among the candidate resources causing exclusion of resources,
1st terminal.

Images