KR20220071950A - Method and apparatus for transmitting data using addition pqi in sidelink communication - Google Patents

Abstract

Disclosed are a method and apparatus for transmitting data using an additional PQI in sidelink communication. An operating method of a terminal includes the steps of: selecting candidate resources by performing a resource sensing operation based on a first PQI value of the terminal; performing a first resource selection operation within the candidate resources based on a second PQI value of the terminal; and performing, when a first transmission resource is selected by the first resource selection operation, sidelink communication by using the selected first transmission resource.

Description

Method and apparatus for data transmission using additional PQI in sidelink communication

The present invention relates to a sidelink communication technique, and more particularly, to a sidelink data transmission technique for ensuring a minimum latency and a packet delay budget (PDB).

4G (4th Generation) communication system (e.g., LTE (Long Term Evolution) communication system, LTE-A (Advanced) communication system) for the processing of rapidly increasing wireless data after the commercialization of the frequency band of the 4G communication system ( For example, a 5th generation (5G) communication system (eg, NR (New Radio) communication system) is being considered. The 5G communication system may support enhanced Mobile BroadBand (eMBB), Ultra-Reliable and Low Latency Communication (URLLC), and Massive Machine Type Communication (mMTC).

The 4G communication system and the 5G communication system may support vehicle to everything (V2X) communication (eg, sidelink communication). V2X communication supported in a cellular communication system, such as a 4G communication system and a 5G communication system, may be referred to as "C-V2X (Cellular-Vehicle to Everything) communication". V2X communication (eg, C-V2X communication) may include Vehicle to Vehicle (V2V) communication, Vehicle to Infrastructure (V2I) communication, Vehicle to Pedestrian (V2P) communication, V2N (Vehicle to Network) communication, etc. .

On the other hand, when mode 2 is used in sidelink communication, the terminal may autonomously select a resource by performing a resource sensing operation (eg, a channel sensing operation) within the resource pool without scheduling of the base station. The UE may determine candidate resources by performing a resource sensing operation, may select transmission resource(s) from among candidate resources by performing a resource selection operation, and perform sidelink communication using the selected transmission resource(s) can do. The UE performs a re-evaluation operation on the transmission resource(s) before performing the sidelink communication (eg, t seconds or t ms (millisecond) before the sidelink communication is performed) By doing so, it is possible to determine whether reselection of the transmission resource(s) is necessary. t may be a natural number.

In sidelink communication, a preemption operation may be supported. According to the preamble operation, a resource allocated for low-priority transmission may be occupied for high-priority transmission. The UE may check whether the transmission resource(s) is preempted by performing a re-evaluation operation. When the transmission resource(s) selected by the resource selection operation are preambled by the preamble operation, the UE may perform the resource selection operation again. That is, the transmission resource(s) selected by the terminal having a low priority may be pre-amplified for transmission of the terminal having a high priority, and in this case, the sidelink transmission of the terminal having a low priority may be delayed. .

An object of the present invention for solving the above problems is a method and apparatus for transmitting data using an additional PQI (PC5 5G NR Standardized QoS indicator) to ensure minimum latency and packet delay budget (PDB) is to provide

In a method of operating a terminal according to a first embodiment of the present invention for achieving the above object, candidate resources are selected by performing a resource sensing operation based on a first PQI value of the terminal, in the candidate resources performing a first resource selection operation based on the second PQI value of the terminal, and when the first transmission resource is selected by the first resource selection operation, sidelink communication is performed using the selected first transmission resource including the steps of

The method of operation of the terminal includes, when the first transmission resource is not selected by the first resource selection operation, increasing the second PQI value, using an increased second PQI value in the candidate resources to perform a second resource selection operation, and when the second transmission resource is selected by the second resource selection operation, performing sidelink communication using the selected second transmission resource.

The performing the second resource selection operation includes comparing the increased second PQI value with a second PQI value of another terminal, and the increased second PQI value is higher than the second PQI value of the other terminal In a large case, the method may include preampling the second transmission resource occupied by the other terminal.

In the first resource selection operation or the second resource selection operation, second PQI values between terminals having the same first PQI value may be compared.

The method of operating a terminal according to a second embodiment of the present invention for achieving the above object includes selecting candidate resources by performing a resource sensing operation based on a first PQI value of the terminal, mapping to the first PQI increasing the second PQI value of the terminal according to proximity information on the PDB to be used, performing a first resource selection operation based on the increased second PQI value in the candidate resources, and the first and performing sidelink communication using the selected first transmission resource when the first transmission resource is selected by the resource selection operation.

에 의해 결정될 수 있고, N_d는 지연 횟수를 의미할 수 있고, T_d는 지연 시간을 의미할 수 있고, y는 상승 상수를 의미할 수 있다.The increase rate of the second PQI is

may be determined by , N _d may mean the number of delays, T _d may mean a delay time, and y may mean a rising constant.

The performing the first resource selection operation includes comparing the increased second PQI value with a second PQI value of another terminal, and the increased second PQI value is higher than the second PQI value of the other terminal In a large case, the method may include preampling the first transmission resource occupied by the other terminal.

The method of operating the terminal includes, when the first transmission resource is not selected by the first resource selection operation, increasing the second PQI value again by reflecting the number of delays in transmission, the candidate resources performing a second resource selection operation using the second PQI value increased again in It may include the step of performing

In the first resource selection operation or the second resource selection operation, second PQI values between terminals having the same first PQI value may be compared.

According to the present application, the second PQI value may be used separately from the first PQI (PC5 5G NR Standardized QoS indicator) value. The terminal may increase the second PQI value when the sidelink transmission fails, may select a transmission resource by performing a resource selection operation using the increased second PQI value, and use the selected transmission resource for sidelink communication can be performed. Alternatively, the UE may increase the second PQI value based on the proximity degree of a packet delay budget (PDB) mapped to the first PQI value, and perform a resource selection operation using the increased second PQI value. A transmission resource may be selected, and sidelink communication may be performed using the selected transmission resource. Accordingly, transmission delay in sidelink communication can be reduced, and PDB can be guaranteed.

1 is a conceptual diagram illustrating scenarios of V2X communication.
2 is a conceptual diagram illustrating a first embodiment of a cellular communication system.
3 is a block diagram illustrating a first embodiment of a communication node constituting a cellular communication system.
4A is a conceptual diagram illustrating resources occupied by a terminal having a high priority.
4B is a conceptual diagram illustrating resources occupied by a terminal having a low priority.
5 is a flowchart illustrating a first embodiment of a resource selection method.
6 is a conceptual diagram illustrating a first embodiment of a resource selection method.
7 is a flowchart illustrating a second embodiment of a resource selection method.

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

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

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

In the embodiments of the present application, (re)transmission may mean "transmission", "retransmission", or "transmission and retransmission", and (re)establishment is "setup", "reset", or "set and may mean "reset", (re)connection may mean "connection", "reconnection", or "connection and reconnection", and (re)connection means "connection", "reconnection", or " connection and reconnection".

When a component is referred to as being “connected” or “connected” to another component, it may be directly connected or connected to the other component, but it is understood that other components may exist in between. it should be On the other hand, when it is said that a certain element is "directly connected" or "directly connected" to another element, it should be understood that the other element does not exist in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

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

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

1 is a conceptual diagram illustrating scenarios of vehicle to everything (V2X) communication.

Referring to FIG. 1 , V2X communication may include Vehicle to Vehicle (V2V) communication, Vehicle to Infrastructure (V2I) communication, Vehicle to Pedestrian (V2P) communication, Vehicle to Network (V2N) communication, and the like. V2X communication may be supported by the cellular communication system (eg, cellular communication network) 140 , and V2X communication supported by the cellular communication system 140 is "C-V2X (Cellular-Vehicle to everything) communication" " can be referred to as Cellular communication system 140 is a 4G (4th Generation) communication system (eg, LTE (Long Term Evolution) communication system, LTE-A (Advanced) communication system), 5G (5th Generation) communication system (eg, NR (New Radio) communication system) and the like.

V2V communication is communication between vehicle #1(100) (eg, a communication node located in vehicle #1(100)) and vehicle #2(110) (eg, a communication node located in vehicle #1(100)). can mean Driving information (eg, velocity, heading, time, position, etc.) may be exchanged between the vehicles 100 and 110 through V2V communication. Based on driving information exchanged through V2V communication, autonomous driving (eg, platooning) may be supported. V2V communication supported by the cellular communication system 140 may be performed based on a sidelink communication technology (eg, Proximity based Services (ProSe) communication technology, Device to Device (D2D) communication technology). . In this case, communication between the vehicles 100 and 110 may be performed using a sidelink channel.

V2I communication may mean communication between the vehicle #1 100 and an infrastructure (eg, a road side unit (RSU)) 120 located on a roadside. The infrastructure 120 may be a traffic light or a street light located on a roadside. For example, when V2I communication is performed, communication may be performed between a communication node located at vehicle #1 ( 100 ) and a communication node located at a traffic light. Driving information, traffic information, and the like may be exchanged between the vehicle #1 100 and the infrastructure 120 through V2I communication. V2I communication supported by the cellular communication system 140 may be performed based on a sidelink communication technology (eg, ProSe communication technology, D2D communication technology). In this case, communication between the vehicle #1 100 and the infrastructure 120 may be performed using a sidelink channel.

V2P communication may mean communication between vehicle #1 ( 100 ) (eg, a communication node located in vehicle #1 ( 100 )) and person 130 (eg, a communication node possessed by person 130 ). can Through V2P communication, driving information of vehicle #1(100) and movement information (eg, speed, direction, time, location, etc.) of vehicle #1(100) and person 130 are exchanged between vehicle #1(100) and person 130 through V2P communication. The communication node located in the vehicle #1 100 or the communication node possessed by the person 130 may generate an alarm indicating danger by determining a dangerous situation based on the acquired driving information and movement information. . V2P communication supported by the cellular communication system 140 may be performed based on a sidelink communication technology (eg, ProSe communication technology, D2D communication technology). In this case, communication between the communication node located in the vehicle #1 100 or the communication node possessed by the person 130 may be performed using a sidelink channel.

V2N communication may refer to communication between vehicle #1 100 (eg, a communication node located in vehicle #1 100 ) and a cellular communication system (eg, cellular communication network) 140 . V2N communication may be performed based on 4G communication technology (eg, LTE communication technology and LTE-A communication technology specified in 3GPP standard), 5G communication technology (eg, NR communication technology specified in 3GPP standard), etc. have. In addition, V2N communication is a communication technology defined in the IEEE (Institute of Electrical and Electronics Engineers) 702.11 standard (eg, WAVE (Wireless Access in Vehicular Environments) communication technology, WLAN (Wireless Local Area Network) communication technology, etc.), IEEE It may be performed based on a communication technology (eg, wireless personal area network (WPAN), etc.) specified in the 702.15 standard.

Meanwhile, the cellular communication system 140 supporting V2X communication may be configured as follows.

2 is a conceptual diagram illustrating a first embodiment of a cellular communication system.

Referring to FIG. 2 , the cellular communication system may include an access network, a core network, and the like. The access network may include a base station 210 , a relay 220 , User Equipment (UE) 231 to 236 , and the like. UEs 231 to 236 may be communication nodes located in vehicles 100 and 110 of FIG. 1 , communication nodes located in infrastructure 120 of FIG. 1 , communication nodes carried by person 130 of FIG. 1 , and the like. When the cellular communication system supports 4G communication technology, the core network is a serving-gateway (S-GW) 250 , a packet data network (PDN)-gateway (P-GW) 260 , and a mobility management entity (MME). (270) and the like.

When the cellular communication system supports 5G communication technology, the core network may include a user plane function (UPF) 250, a session management function (SMF) 260, an access and mobility management function (AMF) 270, and the like. can Alternatively, when NSA (Non-StandAlone) is supported in the cellular communication system, the core network including the S-GW 250 , the P-GW 260 , the MME 270 , etc. is a 4G communication technology as well as a 5G communication technology Also, the core network including the UPF 250 , the SMF 260 , and the AMF 270 may support not only 5G communication technology but also 4G communication technology.

In addition, when the cellular communication system supports a network slicing technology, the core network may be divided into a plurality of logical network slices. For example, a network slice that supports V2X communication (eg, V2V network slice, V2I network slice, V2P network slice, V2N network slice, etc.) may be set, and V2X communication is in the V2X network slice set in the core network. can be supported by

Communication nodes constituting the cellular communication system (eg, base station, relay, UE, S-GW, P-GW, MME, UPF, SMF, AMF, etc.) are CDMA (code division multiple access) technology, WCDMA (wideband) CDMA) technology, TDMA (time division multiple access) technology, FDMA (frequency division multiple access) technology, OFDM (orthogonal frequency division multiplexing) technology, Filtered OFDM technology, 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, and SDMA (Space Division Multiple Access) technology ) technology may be used to perform communication using at least one communication technology.

Communication nodes (eg, base station, relay, UE, S-GW, P-GW, MME, UPF, SMF, AMF, etc.) constituting the cellular communication system may be configured as follows.

3 is a block diagram illustrating a first embodiment of a communication node constituting a cellular communication system.

Referring to FIG. 3 , the communication node 300 may include at least one processor 310 , a memory 320 , and a transceiver 330 connected to a network to perform communication. In addition, the communication node 300 may further include an input interface device 340 , an output interface device 350 , a storage device 360 , and the like. Each of the components included in the communication node 300 may be connected by a bus 370 to communicate with each other.

However, each of the components included in the communication node 300 may not be connected to the common bus 370 but to the processor 310 through an individual interface or an individual bus. For example, the processor 310 may be connected to at least one of the memory 320 , the transceiver 330 , the input interface device 340 , the output interface device 350 , and the storage device 360 through a dedicated interface. .

The processor 310 may execute a program command stored in at least one of the memory 320 and the storage device 360 . The processor 310 may mean a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present invention are performed. Each of the memory 320 and the storage device 360 may be configured of at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 320 may be configured as at least one of a read only memory (ROM) and a random access memory (RAM).

Referring back to FIG. 2 , in the communication system, the base station 210 may form a macro cell or a small cell, and may be connected to the core network through an ideal backhaul or a non-ideal backhaul. The base station 210 may transmit a signal received from the core network to the UEs 231 to 236 and the relay 220, and may transmit a signal received from the UEs 231 to 236 and the relay 220 to the core network. . UEs #1, #2, #4, #5, and #6 (231 , 232 , 234 , 235 , 236 ) may belong to cell coverage of the base station 210 . UEs #1, #2, #4, #5, and #6 (231 , 232 , 234 , 235 , 236 ) may be connected to the base station 210 by performing a connection establishment procedure with the base station 210 . . UEs #1, #2, #4, #5, and #6 (231 , 232 , 234 , 235 , 236 ) may communicate with the base station 210 after being connected to the base station 210 .

The relay 220 may be connected to the base station 210 and may relay communication between the base station 210 and UEs #3 and #4 (233, 234). The relay 220 may transmit a signal received from the base station 210 to the UEs #3 and #4 (233, 234), and transmit the signal received from the UEs #3 and #4 (233, 234) to the base station 210. can be sent to UE #4 234 may belong to the cell coverage of the base station 210 and the cell coverage of the relay 220 , and UE #3 233 may belong to the cell coverage of the relay 220 . That is, UE #3 233 may be located outside the cell coverage of the base station 210 . UEs #3 and #4 ( 233 , 234 ) may be connected to the relay 220 by performing a connection establishment procedure with the relay 220 . UEs #3 and #4 ( 233 , 234 ) may communicate with the relay 220 after being connected to the relay 220 .

The base station 210 and the relay 220 are MIMO (eg, single user (SU)-MIMO, multi user (MU)-MIMO, massive MIMO, etc.) communication technology, CoMP (coordinated multipoint) communication technology, CA (Carrier Aggregation) communication technology, unlicensed band communication technology (eg, Licensed Assisted Access (LAA), enhanced LAA (eLAA)), sidelink communication technology (eg, ProSe communication technology, D2D communication) technology), etc. UEs #1, #2, #5, and #6 (231 , 232 , 235 , 236 ) may perform an operation corresponding to the base station 210 , an operation supported by the base station 210 , and the like. UEs #3 and #4 ( 233 , 234 ) may perform an operation corresponding to the relay 220 , an operation supported by the relay 220 , and the like.

Here, the base station 210 is a NodeB (NodeB), an advanced NodeB (evolved NodeB), a base transceiver station (BTS), a radio remote head (RRH), a transmission reception point (TRP), a radio unit (RU), an RSU ( road side unit), a wireless transceiver (radio transceiver), an access point (access point), may be referred to as an access node (node). The relay 220 may be referred to as a small base station, a relay node, or the like. The UEs 231 to 236 are a terminal, an access terminal, a mobile terminal, a station, a subscriber station, a mobile station, a portable subscriber station. subscriber station), a node, a device, an on-broad unit (OBU), and the like.

Meanwhile, communication between UE #5 235 and UE #6 236 may be performed based on a Cylink communication technology (eg, ProSe communication technology, D2D communication technology). The sidelink communication may be performed based on a one-to-one scheme or a one-to-many scheme. When V2V communication is performed using the Cylink communication technology, UE #5 235 may indicate a communication node located in vehicle #1 100 of FIG. 1 , and UE #6 236 of FIG. 1 . It may indicate a communication node located in vehicle #2 110 . When V2I communication is performed using the Cylink communication technology, UE #5 235 may indicate a communication node located in vehicle #1 100 of FIG. 1 , and UE #6 236 of FIG. 1 . It may indicate a communication node located in the infrastructure 120 . When V2P communication is performed using the Cylink communication technology, UE #5 235 may indicate a communication node located in vehicle #1 100 of FIG. 1 , and UE #6 236 of FIG. 1 . It is possible to indicate the communication node possessed by the person 130 .

Scenarios to which sidelink communication is applied may be classified as shown in Table 1 below according to the locations of UEs (eg, UE #5 (235) and UE #6 (236)) participating in sidelink communication. For example, the scenario for sidelink communication between UE #5 235 and UE #6 236 shown in FIG. 2 may be sidelink communication scenario #C.

On the other hand, the channel used in sidelink communication between UE #5 (235) and UE #6 (236) is PSSCH (Physical Sidelink Shared Channel), PSCCH (Physical Sidelink Control Channel), PSDCH (Physical Sidelink Discovery Channel), PSBCH ( Physical Sidelink Broadcast Channel) and the like. The PSSCH may be used for transmission and reception of sidelink data, and may be configured in a UE (eg, UE #5 (235), UE #6 (236)) by higher layer signaling. The PSCCH may be used for transmission and reception of sidelink control information (SCI), and may be configured in a UE (eg, UE #5 (235), UE #6 (236)) by higher layer signaling. have.

PSDCH may be used for the discovery procedure. For example, the discovery signal may be transmitted through PSDCH. PSBCH may be used for transmission and reception of broadcast information (eg, system information). In addition, a demodulation reference signal (DMRS), a synchronization signal, or the like may be used in sidelink communication between the UE #5 ( 235 ) and the UE #6 ( 236 ). The synchronization signal may include a primary sidelink synchronization signal (PSSS) and a secondary sidelink synchronization signal (SSSS).

Meanwhile, a sidelink transmission mode (TM) may be classified into sidelink TMs #1 to #4 as shown in Table 2 below.

When sidelink TM #3 or #4 is supported, each of UE #5 235 and UE #6 236 performs sidelink communication using a resource pool set by the base station 210. can A resource pool may be configured for each sidelink control information or sidelink data.

A resource pool for sidelink control information may be configured based on an RRC signaling procedure (eg, a dedicated RRC signaling procedure, a broadcast RRC signaling procedure). A resource pool used for reception of sidelink control information may be set by a broadcast RRC signaling procedure. When sidelink TM #3 is supported, a resource pool used for transmission of sidelink control information may be set by a dedicated RRC signaling procedure. In this case, the sidelink control information may be transmitted through a resource scheduled by the base station 210 within the resource pool set by the dedicated RRC signaling procedure. When sidelink TM #4 is supported, a resource pool used for transmission of sidelink control information may be set by a dedicated RRC signaling procedure or a broadcast RRC signaling procedure. In this case, the sidelink control information is autonomously selected by the UE (eg, UE #5 (235), UE #6 (236)) within the resource pool established by the dedicated RRC signaling procedure or the broadcast RRC signaling procedure. It may be transmitted through a resource.

When sidelink TM #3 is supported, a resource pool for transmission and reception of sidelink data may not be set. In this case, sidelink data may be transmitted/received through a resource scheduled by the base station 210 . When sidelink TM #4 is supported, a resource pool for transmission and reception of sidelink data may be set by a dedicated RRC signaling procedure or a broadcast RRC signaling procedure. In this case, the sidelink data is the resource autonomously selected by the UE (eg, UE #5 (235), UE #6 (236)) within the resource pool set by the RRC signaling procedure or the broadcast RRC signaling procedure. can be transmitted and received through

Next, sidelink communication methods will be described. Even when a method (eg, transmission or reception of a signal) performed in a first communication node among communication nodes is described, a corresponding second communication node is a method (eg, a method corresponding to the method performed in the first communication node) For example, reception or transmission of a signal) may be performed. That is, when the operation of UE #1 (eg, vehicle #1) is described, the corresponding UE #2 (eg, vehicle #2) may perform an operation corresponding to that of UE #1. have. Conversely, when the operation of UE #2 is described, the corresponding UE #1 may perform the operation corresponding to the operation of UE #2. In the embodiments described below, the operation of the vehicle may be that of a communication node located in the vehicle.

In embodiments, signaling may be one or a combination of two or more of higher layer signaling, MAC signaling, and PHY (physical) signaling. A message used for higher layer signaling may be referred to as an "upper layer message" or a "higher layer signaling message". A message used for MAC signaling may be referred to as a “MAC message” or a “MAC signaling message”. A message used for PHY signaling may be referred to as a “PHY message” or a “PHY signaling message”. Higher layer signaling may refer to an operation of transmitting and receiving system information (eg, a master information block (MIB), a system information block (SIB)) and/or an RRC message. MAC signaling may refer to a transmission/reception operation of a MAC control element (CE). PHY signaling may refer to a transmission/reception operation of control information (eg, downlink control information (DCI), uplink control information (UCI), and SCI).

The sidelink signal may be a synchronization signal and a reference signal used for sidelink communication. For example, the synchronization signal may be a synchronization signal/physical broadcast channel (SS/PBCH) block, a sidelink synchronization signal (SLSS), a primary sidelink synchronization signal (PSSS), a secondary sidelink synchronization signal (SSSS), and the like. The reference signal is a channel state information-reference signal (CSI-RS), DMRS, phase tracking-reference signal (PT-RS), cell specific reference signal (CRS), sounding reference signal (SRS), discovery reference signal (DRS), etc. can

The sidelink channel may be PSSCH, PSCCH, PSDCH, PSBCH, physical sidelink feedback channel (PSFCH), or the like. In addition, the sidelink channel may mean a sidelink channel including a sidelink signal mapped to specific resources in the corresponding sidelink channel. The sidelink communication may support a broadcast service, a multicast service, a groupcast service, and a unicast service.

The sidelink communication may be performed based on a single SCI scheme or a multi-SCI scheme. When a single SCI scheme is used, data transmission (eg, sidelink data transmission, SL-SCH (sidelink-shared channel) transmission) is performed based on one SCI (eg, 1 ^st -stage SCI). can be When the multiple SCI scheme is used, data transmission may be performed using two SCIs (eg, 1 ^st -stage SCI and 2 ^nd -stage SCI). SCI may be transmitted through PSCCH and/or PSSCH. When a single SCI scheme is used, the SCI (eg, 1 ^st -stage SCI) may be transmitted in the PSCCH. When the multiple SCI scheme is used, 1 ^st -stage SCI may be transmitted on PSCCH, and 2 ^nd -stage SCI may be transmitted on PSCCH or PSSCH. 1 ^st -stage SCI may be referred to as "first stage SCI", and 2 ^nd -stage SCI may be referred to as "second stage SCI". The first step SCI format may include SCI format 1-A, and the second step SCI format may include SCI format 2-A and SCI format 2-B.

The first step SCI is priority information, frequency resource assignment information, time resource allocation information, resource reservation period information, DMRS (demodulation reference signal) pattern information, the second step SCI It may include one or more information elements among format information, beta_offset indicator, the number of DMRS ports, and modulation and coding scheme (MCS) information. The second step SCI is HARQ processor ID (identifier), RV (redundancy version), source (source) ID, destination (destination) ID, CSI request (request) information, zone (zone) ID, and communication range requirements (communication) range requirement) may include one or more information elements.

4A is a conceptual diagram illustrating resources occupied by a terminal having a high priority, and FIG. 4B is a conceptual diagram illustrating resources occupied by a terminal having a low priority.

4A and 4B, terminals 11 to 14 may be terminals having a high priority (hereinafter, referred to as "higher priority (HP) terminals"), and terminals 21 to 29 are terminals having a low priority. It may be a terminal (hereinafter, referred to as a "lower priority (LP) terminal"). The PQI (PC5 5G NR Standardized QoS indicator) value of UE 11 may be 21, the PQI value of UE 12 may be 23, the PQI value of UE 13 may be 55, and the PQI value of UE 14 may be 59 have. Each of terminals 21 to 29 may have a PQI value of 90.

HP terminals may first select a transmission resource(s) in the resource pool. In addition, the HP terminals may preamplify the transmission resource(s) selected by the LP terminal by performing a preemption operation. For example, the resource pool may be composed of 32 resource regions, and 25 resource regions among the 32 resource regions may be determined as transmission resources of HP terminals. In the time domain, the resource region may be configured in units of symbols, mini-slots, slots, or subframes. In the frequency domain, the resource region may be configured in units of subcarriers, physical resource blocks (PRBs), or subchannels.

Among the 32 resource regions in the resource pool, the remaining 7 resource regions may be candidate resource sets (eg, candidate resources) of 9 LP terminals. When one LP terminal selects one resource region to perform sidelink communication, two LP terminals among nine LP terminals cannot perform sidelink communication. In this case, the sidelink communication of the two LP terminals may be delayed. Alternatively, sidelink communication of two LP terminals may not be possible.

To solve the above-mentioned problem, an additional PQI may be introduced. The PQI defined in the existing 3GPP standard may be referred to as a first PQI, and the additional PQI proposed in the present application may be referred to as a second PQI. By using the second PQI as well as the first PQI in sidelink communication, the problem caused by repeated preemption in terminals supporting the same service can be solved, and fair resource allocation can be guaranteed. .

5 is a flowchart illustrating a first embodiment of a resource selection method.

Referring to FIG. 5 , mode 2 (eg, sidelink TM #2 or #4 defined in Table 2) in sidelink communication may be supported, and the terminal may support a signal including a first PQI and a second PQI and/or transmit a channel (eg, data). The embodiment shown in Fig. 5 can be applied to the scenarios shown in Figs. 4A and 4B. The nine LP terminals shown in FIG. 4B may determine a candidate resource set (eg, nine resource regions) by performing a resource sensing operation. The resource sensing operation may be performed based on the first PQI values of the nine LP terminals. In an embodiment, it may be assumed that the first PQI values of the nine LP terminals are the same. One terminal (hereinafter, referred to as "a first terminal") among nine LP terminals may perform a first resource selection operation in a candidate resource set (S501). The first resource selection operation may be performed based on the second PQI value. When the transmission resource is not selected by the first resource selection operation, the first terminal may increase its own second PQI value (S502). After increasing the second PQI value, the first terminal may perform a second resource selection operation in the candidate resource set (S503). The second resource selection operation may be performed after the first resource selection operation. In step S503, the first terminal may compare its own second PQI value with the second PQI value of another terminal. When the second PQI value of the first terminal is greater than the second PQI value of other terminals, the first terminal may select transmission resource(s) from the candidate resource set. In this case, the first terminal may preamble the transmission resource selected by the other terminal. The first terminal and the other terminal may have the same first PQI value. The first terminal may perform sidelink communication using the selected transmission resource(s) (S504). The embodiment described with reference to FIG. 5 may be performed as shown in FIG. 6 below.

6 is a conceptual diagram illustrating a first embodiment of a resource selection method.

Referring to FIG. 6 , terminals 21 to 29 may be terminals 21 to 29 (eg, 9 LP terminals) illustrated in FIG. 4B , and may have the same first PQI value. In FIG. 6A , terminals 21 to 27 may occupy candidate resources and may perform sidelink communication using the occupied candidate resources (ie, transmission resources). On the other hand, the terminals 28 and 29 may not be able to select a transmission resource and thus may not perform sidelink communication. In this case, each of the terminals 28 and 29 may increase its own second PQI value. In this case, the increased second PQI values of terminals 28 and 29 may be greater than the second PQI values of other terminal(s).

In (b) of FIG. 6 , since the second PQI values of terminals 28 and 29 are greater than the second PQI values of other terminal(s), terminals 28 and 29 may preamble resources of other terminal(s). . Accordingly, the terminals 21 to 25 and 28 to 29 may occupy candidate resources and may perform sidelink communication using the occupied candidate resources (ie, transmission resources). On the other hand, terminals 26 and 27 may not be able to select a transmission resource and thus may not be able to perform sidelink communication. In this case, each of the terminals 26 and 27 may increase its own second PQI value. In this case, the increased second PQI values of terminals 26 and 27 may be greater than the second PQI values of other terminal(s).

In FIG. 6(c) , since the second PQI values of terminals 26 and 27 are greater than the second PQI values of other terminal(s), terminals 26 and 27 may preamble the resources of other terminal(s). . Accordingly, the terminals 21 to 23 and 26 to 29 may occupy candidate resources and may perform sidelink communication using the occupied candidate resources (ie, transmission resources). On the other hand, the terminals 24 and 25 may not be able to select a transmission resource and thus may not perform sidelink communication. In this case, each of the terminals 24 and 25 may increase its own second PQI value. In this case, the increased second PQI values of terminals 24 and 25 may be greater than the second PQI values of other terminal(s).

In FIG. 6(d) , since the second PQI values of terminals 24 and 25 are greater than the second PQI values of other terminal(s), terminals 24 and 25 may preamble resources of other terminal(s). . Accordingly, the terminals 21 and 24-29 may occupy candidate resources and may perform sidelink communication using the occupied candidate resources (ie, transmission resources). On the other hand, terminals 22 and 23 may not be able to select a transmission resource and thus may not perform sidelink communication. In this case, each of the terminals 22 and 23 may increase its own second PQI value. In this case, the increased second PQI values of terminals 22 and 23 may be greater than the second PQI values of other terminal(s).

In FIG. 6(e), since the second PQI values of terminals 22 and 23 are greater than the second PQI values of other terminal(s), terminals 22 and 23 may preamble the resources of other terminal(s). . Accordingly, the terminals 22 to 28 may occupy candidate resources and may perform sidelink communication using the occupied candidate resources (ie, transmission resources). On the other hand, the terminals 21 and 29 may not be able to perform sidelink communication because they cannot select a transmission resource. In this case, each of the terminals 21 and 29 may increase its own second PQI value. In this case, the increased second PQI values of terminals 21 and 29 may be greater than the second PQI values of other terminal(s).

Meanwhile, as another method, the second PQI value of the terminal may be adjusted based on a packet delay budget (PDB). The first PQI may be mapped to a predefined PDB. It is preferable that a terminal having a data packet close to the PDB selects a resource in preference to other terminals supporting the same service. Here, the terminal supporting the same service may be a terminal having the same first PQI value. Accordingly, the resource selection method may be performed as follows.

7 is a flowchart illustrating a second embodiment of a resource selection method.

Referring to FIG. 7 , mode 2 (eg, sidelink TM #2 or #4 defined in Table 2) in sidelink communication may be supported, and the terminal may support a signal including a first PQI and a second PQI and/or transmit a channel (eg, data). The terminal may perform a resource sensing operation, a resource selection operation, and/or a re-evaluation operation (S701). When selection of a transmission resource fails due to the above-described operation, the terminal may increase the second PQI value according to the degree of proximity to the PDB mapped to its first PQI value (S702). In step S702, the terminal may determine the degree of proximity of the PDB by comparing the delay for its own packet with the PDB mapped to the first PQI value. When the degree of proximity of the PDB is less than the threshold value, the terminal may increase its own second PQI value. The increase rate of the second PQI value may be determined based on Equation 1 below.

N _d may mean the number of delays, T _d may mean a delay time (eg, delay time in one delay), and y may mean a rising constant .

The UE may perform a resource selection operation based on the increased second PQI value (S703). In step S703, the terminal may compare the increased second PQI value with the second PQI value of the other terminal, and when the increased second PQI value is greater than the second PQI value of the other terminal, the transmission resource of the other terminal is freed can do an amp. Here, the operation of comparing the second PQI value may be performed between terminals having the same first PQI value. When a transmission resource is selected in step S703, the terminal may perform sidelink communication using the selected transmission resource (S704). If the transmission resource is not selected in step S703, the terminal may perform again from step S702.

According to the above-described operation, a second PQI value of a terminal that has failed a lot of transmission among terminals having the same first PQI value may be increased, and thus fair resource allocation may be possible. In addition, according to the above-described operation, the PDB can be guaranteed.

The methods according to the present invention may be implemented in the form of program instructions that can be executed by various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc. alone or in combination. The program instructions recorded on the computer-readable medium may be specially designed and configured for the present invention, or may be known and available to those skilled in the art of computer software.

Examples of computer-readable media include hardware devices specially configured to store and carry out program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as at least one software module to perform the operations of the present invention, and vice versa.

Although it has been described with reference to the above embodiments, it will be understood by those skilled in the art that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. will be able

Claims (9)

A method of operating a terminal in a communication system, comprising:
selecting candidate resources by performing a resource sensing operation based on a first PC5 5G NR Standardized QoS indicator (PQI) value of the terminal;
performing a first resource selection operation based on a second PQI value of the terminal in the candidate resources; and
and performing sidelink communication using the selected first transmission resource when the first transmission resource is selected by the first resource selection operation. The method according to claim 1,
The method of operation of the terminal,
increasing the second PQI value when the first transmission resource is not selected by the first resource selection operation;
performing a second resource selection operation using an increased second PQI value in the candidate resources; and
and performing sidelink communication using the selected second transmission resource when a second transmission resource is selected by the second resource selection operation. 3. The method according to claim 2,
The step of performing the second resource selection operation,
comparing the increased second PQI value with a second PQI value of another terminal; and
and preempting the second transmission resource occupied by the other terminal when the increased second PQI value is greater than the second PQI value of the other terminal. 3. The method according to claim 2,
In the first resource selection operation or the second resource selection operation, a second PQI value is compared between terminals having the same first PQI value. A method of operating a terminal in a communication system, comprising:
selecting candidate resources by performing a resource sensing operation based on a first PC5 5G NR Standardized QoS indicator (PQI) value of the terminal;
increasing a second PQI value of the terminal according to proximity information on a packet delay budget (PDB) mapped to the first PQI;
performing a first resource selection operation based on a second PQI value increased in the candidate resources; and
and performing sidelink communication using the selected first transmission resource when the first transmission resource is selected by the first resource selection operation. 6. The method of claim 5,
The increase rate of the second PQI is determined based on the following equation,

N _d means the number of delays, T _d means delay time, y means a rising constant (rising constant), the terminal operating method. 6. The method of claim 5,
The step of performing the first resource selection operation,
comparing the increased second PQI value with a second PQI value of another terminal; and
and preempting the first transmission resource occupied by the other terminal when the increased second PQI value is greater than the second PQI value of the other terminal. 6. The method of claim 5,
The method of operation of the terminal,
increasing the second PQI value again by reflecting the number of transmission delays when the first transmission resource is not selected by the first resource selection operation;
performing a second resource selection operation using a second PQI value increased again in the candidate resources; and
and performing sidelink communication using the selected second transmission resource when a second transmission resource is selected by the second resource selection operation. 9. The method of claim 8,
In the first resource selection operation or the second resource selection operation, a second PQI value is compared between terminals having the same first PQI value.

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