RU2772319C2 - Method for resource distribution and device for supporting vehicle communication in the next generation mobile communication system - Google Patents

Abstract

FIELD: communications.

SUBSTANCE: invention relates to the field of communications. The data transmission method includes receiving system information including a V2X parameter, receiving a data packet based on the V2X parameter, and updating a state variable on the data packet when the data packet is related to a new service, wherein the sequence number included in the state variable is updated based on the sequence number. number of the data packet received for the first time.

EFFECT: enabling the definition of a pool of individual resource services to support various vehicle-to-all (V2X) services in a mobile communication system.

16 cl, 1 tbl, 24 dwg

Description

Technical field

[1] The disclosure defines a pool of service-specific resources to support various vehicle-to-all (V2X) services in a next generation mobile communication system. In addition, the disclosure includes a resource pool selection method by an LTE terminal or an NR terminal supporting V2X when a service-specific resource pool and a service-indifferent resource pool coexist, and control (monitoring) and data transmission procedures, respectively.

[2] In addition, the disclosure relates to a mobile communication system, and more specifically, includes a complete process in the user plane of a terminal supporting vehicle-to-all (V2X) services, which are newly defined in NR.

Prior Art

[3] In order to meet the demand for wireless data traffic increased due to the deployment of 4G communication systems, attempts have been made to develop an improved 5G or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called "Non-4G network" or "Post-LTE system". The 5G communication system is considered to be implemented in higher frequency (mm wave) bands, such as 60 GHz bands, in order to achieve higher data rates. In order to reduce radio wave propagation loss and increase the transmission distance, beamforming, massive multiple input/multiple output (MIMO), full size MIMO (FD-MIMO), antenna arrays, analog beamforming, large-scale antennas are discussed in 5G communication systems. In addition, 5G communication systems are developing system network enhancements based on advanced small cells, cloud-based radio access networks (RAN), ultra-dense networks, device-to-device (D2D), wireless backhaul, mobile network, collaborative communication, coordinated multipoint (CoMP), receive-side interference compensation, and the like. In the 5G system, FSK and QAM Hybrid Modulation (FQAM) and Sliding Window Superposition Coding (SWSC) have also been developed as advanced coding modulation (ACM), as well as filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) as an advanced access technology.

[4] The Internet, which is a network of people-centric connectivity where people generate and consume information, is currently evolving into the Internet of Things (IoT), where distributed objects such as things exchange and process information without human intervention. The Internet of Everything (IoE) has emerged, which is a combination of IoT technology and big data processing technology through a connection to a cloud server. Since the implementation of the IoT required technology elements such as "sensing (sensing) technology", "wired/wireless communication and network infrastructure", "service interface technology" and "security technology", the sensor network, machine-to-machine communication, and machine (M2M), Machine Type Communication (MTC) and so on. Such an IoT environment can provide Internet technology intelligent services that create a new quality of human life through the collection and analysis of data generated among connected things. IoT can be applied to a variety of fields, including smart home, smart building, smart city, smart car or connected cars, smart grid, healthcare, smart home appliances and advanced medical services, through convergence and combination between existing information technology (IT) and various industrial applications.

[5] Accordingly, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as sensor network, machine type communication (MTC), and machine-to-machine (M2M) communications can be implemented through beamforming, MIMO, and antenna arrays. The application of cloud radio access network (RAN) as the big data processing technology described above can also be considered as an example of convergence of 5G technology with IoT technology.

[6] Meanwhile, a need has arisen for a method for supporting vehicle-to-all (V2X) services in a 5G communication system.

Description of the invention

Technical problem

[7] The disclosure aims to support various vehicle-to-all (V2X) services by defining a service-specific resource pool in a next generation mobile communication system and designing terminal and base station operations, respectively.

[8] In addition, in order to satisfy the new requirements in NR, in addition to the V2X operation in the existing LTE, it is necessary to configure the operation in the basic user plane required by the introduction of the updated scenario and the NR V2X operation that satisfies the requirements. The user plane operation includes tasks such as MAC PDU format determination, radio bearer administration and initial configuration, and security key configuration.

Solution

[9] In order to solve the above problems, in a wireless communication system, a terminal method according to the disclosure may include: receiving system information including V2X parameters; receiving a data packet based on the V2X parameter; and updating the state variable for the data packet if the data packet is for a new service, wherein the sequence number included in the state variable is updated based on the sequence number of the first received data packet.

[10] In order to solve the above problems, in a wireless communication system, a terminal according to the disclosure may include a transceiver and a controller configured to: receive system information including V2X parameters; receive a data packet based on the V2X parameter; and updating the state variable for the data packet if the data packet is for a new service, wherein the sequence number included in the state variable is updated based on the sequence number of the first received data packet.

Useful results of the invention

[11] According to an embodiment of the disclosure, a pool of service-specific resources is defined to support various vehicle-to-all (V2X) services in a next generation mobile communication system. In addition, the disclosure proposes a complete operation method and apparatus for a terminal and a base station, based on a proposed pool of service-specific resources. Therefore, the base station can support various V2X services for the terminal through efficient resource management with low signaling overhead for an LTE terminal or an NR terminal supporting V2X services, and the terminal can efficiently send and receive messages according to the V2X service.

[12] According to another embodiment of the disclosure, by specifying the features on the user plane to support the V2X NR service, it becomes possible to clarify the V2X NR operation and operation method based on the NR system. Accordingly, it becomes possible to efficiently provide V2X services in the existing NR system.

Brief description of the drawings

[13] FIG. 1A is a view illustrating the structure of an LTE system to which the disclosure may apply;

[14] FIG. 1B is a view illustrating the structure of a radio protocol in an LTE system to which the disclosure may apply;

[15] FIG. 1C is a view illustrating the structure of a next generation mobile communication system to which the disclosure may be applied;

[16] FIG. 1D is a view illustrating the radio protocol structure of a next generation mobile communication system to which the disclosure may be applied;

[17] FIG. 1E is a view illustrating V2X communication in a next generation mobile communication system to which the disclosure applies;

[18] FIG. 1F is a view illustrating a procedure for monitoring and transmitting data of a V2X terminal operating in Mode 3 when a pool of service-specific resources and a pool of service-indifferent resources coexist in a next generation mobile communication system;

[19] FIG. 1G is a view illustrating a data transmission procedure of a V2X terminal operating in Mode 4 when a pool of service-specific resources and a pool of service-indifferent resources coexist in a next generation mobile communication system;

[20] FIG. 1H is a view illustrating a block configuration of a terminal according to the disclosure;

[21] FIG. 1I is a block diagram showing the configuration of a base station according to the disclosure;

[22] FIG. 2A is a view illustrating the structure of an LTE system according to the disclosure;

[23] FIG. 2B is a view illustrating the structure of a radio protocol in an LTE system according to the disclosure;

[24] FIG. 2C is a view illustrating the structure of a next generation mobile communication system to which the disclosure applies;

[25] FIG. 2D is a view illustrating the radio protocol structure of the next generation mobile communication system to which the disclosure applies;

[26] FIG. 2E is a view illustrating V2X communication in a cellular deployment system;

[27] FIG. 2F is a view illustrating a data transmission procedure of a V2X terminal operating in mode 3 according to the disclosure;

[28] FIG. 2G is a view illustrating a data transmission procedure of a V2X terminal operating in mode 4 according to the disclosure;

[29] FIG. 2H is a view illustrating the MAC PDU format applied to the NR V2X system proposed in the disclosure;

[30] FIG. 2I is a view illustrating methods of sidelink (direct connection) radio bearer administration, encryption and decryption applied to the NR V2X system proposed in the disclosure;

[31] FIG. 2J is a view illustrating the complete operation of transmitting and receiving data in the user plane in the NR V2X system proposed by the disclosure;

[32] FIG. 2KA and 2KB are views illustrating in detail the operation of user plane radio bearer administration and terminal encryption supporting NR V2X proposed in the embodiment of the disclosure;

[33] FIG. 2L is a view illustrating a block configuration of a terminal according to an embodiment of the disclosure; and

[34] FIG. 2M is a view illustrating a block configuration of a base station according to an embodiment of the disclosure.

Mode of carrying out the invention

[35] <First Embodiment>

[36] Hereinafter, the operating principle of the disclosure will be described in detail in conjunction with the accompanying drawings. In the following description of the disclosure, a detailed description of known functions or configurations included herein will be omitted when it may make the subject matter of the disclosure unnecessarily obscure. The terms to be described below are terms defined in view of the functions in the disclosure and may differ according to users, users' intentions or habits. Therefore, definitions of terms should be made based on the content in the entire specification.

[37] In the following description of the disclosure, a detailed description of known functions or configurations included herein will be omitted when it may make the subject matter of the disclosure unnecessarily obscure. Next, embodiments of the disclosure will be described with reference to the accompanying drawings.

[38] In the following description, terms for identifying access nodes, terms for network entities, terms for messages, terms for interfaces between network entities, terms for various identities, and the like are used illustratively for the purpose of facilities. Therefore, the disclosure is not limited to terms as used below, and other terms relating to subjects having equivalent technical meanings may be used.

[39] In the following description, the disclosure uses terms and naming conventions defined in the 3rd Generation Partnership Project Long Term Evolution (3GPP LTE) standards for convenience of description. However, the disclosure is not limited to these terms and denominations and may apply similarly to systems that conform to other standards. In the disclosure, the term "eNB" may be used interchangeably with the term "gNB" for convenience of description. That is, a base station described as "eNB" may indicate "gNB".

[40]

[41] FIG. 1A is a view illustrating the structure of an LTE system to which the disclosure may apply.

[42] With reference to FIG. 1A, as illustrated, the radio access network of the LTE system may include evolved Node Bs (hereinafter referred to as ENB, Node B or base station) 1a-05, 1a-10, 1a-15 and 1a-20, mobility management entity 1a-25 (MME) and Serving Gateway (S-GW) 1a-30. The user equipment (hereinafter referred to as "UE" or "terminal") 1a-35 can access the external network through ENB 1a-05 ~ 1a-20 and S-GW 1a-30.

[43] FIG. 1A, ENB 1a-05-1a-20 correspond to the existing Node B of the UMTS system. The ENB is connected to the UE 1a-35 via a radio channel and performs a more complex role than the existing Node B. In the LTE system, all user traffic, including real-time services such as Voice over IP (VoIP) over Internet Protocol, is served via the channel used, the device is required to schedule by collecting state information such as buffer status, available transmission power status, and channel status of the UE, and ENB 1a-05-1a-20 are responsible for the device. One ENB typically manages multiple cells. For example, in order to realize a transmission rate of 100 Mbps, the LTE system uses orthogonal frequency division multiplexing (OFDM) as a radio access technology, for example, in a bandwidth of 20 MHz. In addition, an adaptive modulation & coding scheme (hereinafter referred to as “AMC”) is applied to determine a modulation scheme and a channel coding rate according to the channel state of the terminal.

[44] S-GW 1a-30 is a device that provides a bearer and generates or deletes a bearer under control of MME 1a-25. The MME is a device responsible for various management functions as well as mobility management functions for the terminal, and is connected to a plurality of base stations.

[45] FIG. 1B is a view illustrating the structure of a radio protocol in an LTE system to which the disclosure may apply.

[46] With reference to FIG. 1B, the radio protocol of the LTE system is composed of packet data convergence protocols (PDCP) 1b-05, 1b-40, radio link control (RLC) 1b-10, 1b-35, and medium access control (MAC) 1b-15, 1b-30. in the terminal and eNB, respectively.

[47] Packet Data Convergence Protocols (PDCP) 1b-05, 1b-40 are responsible for operations such as IP header compression/recovery. The main functions of PDCP are summarized below.

[48] - Header compression and decompression: ROHC only

[49] - User data transfer

[50] - Serial delivery of the upper layer PDU in the PDCP re-establishment procedure for RLC AM

[51] - For split bearers in DC (RLC AM support only): PDCP PDU routing for transmission and PDCP PDU reordering for reception

[52] - Low Layer SDU Duplication Detection in RLC AM PDCP Reset Procedure

[53] - Retransmission of PDCP SDU in handover and, for split bearers in DC, PDCP PDU in PDCP data recovery procedure, for RLC AM

[54] - Encryption and decryption

[55] - Timer-based uplink SDU discard

[56]

[57] The Radio Link Controls (RLC) 1b-10 and 1b-35 recover the PDCP Packet Data Unit (PDU) in the proper size and perform the ARQ operation. The main functions of the RLC are summarized below.

[58] - Upper Layer PDU Transfer

[59] - Error Correction via ARQ (for AM data transfer only)

[60] - RLC SDU Concatenation, Segmentation and Reassembly (for UM and AM data transfer only)

[61] - RLC data PDU resegmentation (for AM data transfer only)

[62] - RLC data PDU reordering (for UM and AM data transfer only)

[63] - Duplication detection (only for UM and AM data transfer)

[64] - Protocol error detection (only for AM data transfer)

[65] - Drop RLC SDU (for UM and AM data transfer only)

[66] - Reinstall RLC

[67] The MACs 1b-15 and 1b-30 are connected to multiple RLC layer entities configured in one UE and perform an operation of multiplexing an RLC PDU into a MAC PDU and demultiplexing an RLC PDU from a MAC PDU. The main functions of the MAC are summarized below.

[68] - Mapping (correlation) between logical channels and transport channels

[69] - Multiplexing/demultiplexing MAC SDUs belonging to the same or different logical channels to/from transport blocks (TBs) delivered to/from the physical layer on transport channels

[70] - Message scheduling information

[71] - Bug fix via HARQ

[72] - Priority processing between logical channels of the same UE

[73] - Priority processing between UEs through dynamic scheduling

[74] - MBMS Service Identification

[75] - Transport Format Selection

[76] - Filling

[77] The physical layers 1b-20 and 1b-25 channel-code and modulate the upper layer data, convert it into OFDM symbols and transmit it to the radio channel, or demodulate the OFDM symbols received via the radio channel, decode the channel and deliver it to the upper layer.

[78] FIG. 1C is a view illustrating the structure of a next generation mobile communication system to which the disclosure may be applied.

[79] With reference to FIG. 1C, as illustrated, a radio access network of a next generation mobile communication system (hereinafter referred to as "NR" or "5G") includes a next generation base station 1c-10 (new radio Node B, hereinafter referred to as "NR gNB" or "base NR Station") and New Radio Core Network 1c-05 (NR CN). The user equipment (new radio user equipment, hereinafter referred to as "NR UE" or "terminal") 1c-15 accesses the external network via NR gNB 1c-10 and NR CN 1c-05.

[80] FIG. 1C, NR gNB 1c-10 corresponds to the eNB of the current LTE system. The NR gNB is connected to the NR UE 1c-15 via a radio channel and can provide a service superior to that of the existing Node B. In the next generation mobile communication system, all user traffic is served through a shared channel, so a device is required that collects and schedules status information, such as buffer status, available transmit power status and channel status of the UE, and the responsibility is NR NB 1c-10.

[81] One NR gNB typically manages multiple cells. In order to realize ultra-high-speed data transmission compared to the current LTE, it can have a larger maximum bandwidth than the existing one, and the beamforming technology can be further transplanted using orthogonal frequency division multiplexing (OFDM) as a wireless access technology. In addition, an adaptive modulation coding (AMC) method is applied to determine a modulation scheme and a channel coding rate according to the channel state of the terminal.

[82] NR CN 1c-05 performs functions such as mobility support, bearer configuration, and QoS configuration. The NR CN is a device responsible for various management functions as well as mobility management functions for the terminal, and is connected to a plurality of base stations. In addition, the next generation mobile communication system can be interconnected with the existing LTE system, and the NR CN is connected to the MME 1c-25 via a network interface. The MME is connected to the existing eNB 1c-30.

[83] FIG. 1D is a view illustrating the radio protocol structure of a next generation mobile communication system to which the disclosure may be applied.

[84] With reference to FIG. 1D, the radio protocol of the next generation mobile communication system is composed of NR PDCP 1d-05, 1d-40, NR RLC 1d-10, 1d-35, NR MAC 1d-15, 1d-30 at the terminal, and base station NR, respectively. NR PDCP core features 1d-05, 1d-40 may include some of the following features.

[85] - Header compression and decompression: ROHC only

[86] - User data transfer

[87] - Sequential Delivery of Upper Layer PDUs

[88] - Inconsistent High Layer PDU Delivery

[89] - PDCP PDU Reordering for Receive

[90] - Low Layer SDU Duplication Detection

[91] - PDCP SDU Retransmission

[92] - Encryption and Decryption

[93] - Timer-based uplink SDU discard

[94] In the above, the PDCP NR device reordering function refers to a function of reordering PDCP PDUs received from a lower layer in order based on a PDCP sequence number (SN), and may include a function of delivering data to an upper layer in a reordered order, may include a function of immediate data delivery without regard to the queue, may include a function of reordering and recording of lost PDCP PDUs, may include a function of reporting the status of lost PDCP PDUs to the transmission side, and may include a function of requesting retransmission of lost PDCP PDUs.

[95] The basic functions of the NR RLC 1d-10, 1d-35 may include some of the following functions.

[96] - Upper Layer PDU Transfer

[97] - Sequential Delivery of Upper Layer PDUs

[98] - Inconsistent Delivery of Upper Layer PDUs

[99] - Bug fix via ARQ

[100] - RLC SDU Concatenation, Segmentation and Reassembly

[101] - RLC Data PDU Resegmentation

[102] - RLC Data PDU Reordering

[103] - Duplication Detection

[104] - Protocol Error Detection

[105] - Drop RLC SDU

[106] - Reinstall RLC

[107] In the above, the NR RLC device serial delivery function refers to the sequential delivery function of RLC SDUs received from the lower layer to the upper layer, and may include a reassembly and delivery function when one RLC SDU is initially divided into a plurality of RLC SDUs. and received, may include a function to reorder received RLC PDUs based on an RLC sequence number (SN) or a PDCP sequence number (SN), may include a reorder function for recording lost RLC PDUs, may include a function to report a lost RLC status PDU to the transmission side, may include a function to request retransmission of lost RLC PDUs, may include a function to sequentially deliver only RLC SDUs before a lost RLC SDU to the upper layer when there is a lost RLC SDU, may include a function to sequentially deliver all RLCs SDUs received before the start of the timer, to the upper layer if predefined the timer has expired even if there is a lost RLC SDU, or may include a function to sequentially deliver all RLC SDUs already received to the upper layer if a predetermined timer has expired even if there is a lost RLC SDU. In addition, RLC PDUs may be processed in order of receipt (regardless of the order of the serial number and sequence number, in order of arrival) and delivered to the PDCP device regardless of the order (non-sequential delivery), and, in the case of a segment, the segments stored in the buffer or to be received in the future may be received, reconstructed into one complete RLC PDU, processed, and delivered to the PDCP device. The NR RLC layer may not include the concatenation function, and the function may be performed in the NR MAC layer, or may be replaced by the multiplexing function of the NR MAC layer.

[108] In the above, the non-sequential delivery function of the NR RLC device refers to the function of directly delivering the RLC SDUs received from the lower layer to the upper layer regardless of the order, and may include the function of reassembling and delivering when one RLC SDU is initially divided into a plurality of RLC SDUs and received, and may include a function of storing the RLC SN or PDCP SN of the received RLC PDUs, sorting the order, and recording the lost RLC PDUs.

[109] NR MAC 1d-15 and 1d-30 may be connected to multiple NR RLC layer entities configured in one terminal, and the basic functions of the NR MAC may include some of the following functions.

[110] - Mapping between logical channels and transport channels

[111] - MAC SDU Multiplexing/Demultiplexing

[112] - Message scheduling information

[113] - Bug fix via HARQ

[114] - Priority processing between logical channels of the same UE

[115] - Priority processing between UEs through dynamic scheduling

[116] - MBMS Service Identification

[117] - Select transport format

[118] - Filling

[119] NR PHY layers 1d-20, 1d-25 may channel-code and modulate upper layer data, convert it to OFDM symbols and transmit them to a radio channel, or demodulate and channel-decode OFDM symbols received over a radio channel and transmit them on upper level.

[120] In the disclosure, a pool of service-specific resources is defined to support various vehicle-to-all (V2X) services in a next generation mobile communication system. In particular, in next generation mobile communication systems, since requirements are very different according to use cases, a pool of service-specific resources is defined in the serving cell and between frequencies to support different V2X services. In addition, the disclosure proposes a method for an LTE terminal or an NR terminal supporting V2X services to select a resource pool when the service-specific resource pool and the service-indifferent resource pool proposed above coexist, and proposes a data control and transmission procedure according to way.

[121] Table 1 shows the classification of type, rank, and data rate for each V2X service in the next generation mobile communication system to which the disclosure applies.

[122] With reference to Table 1, unlike existing LTE systems (14/15 V2X releases), which only support unified V2X services such as low data rate such as Basic Security Message (BSM), Shared Inform Message ( CAM), decentralized environmental notification message (DENM), one-way P2X service, etc., a wide range of communication or transmission and public services, the next generation mobile communication systems are expected to support various data rates, communication and transmission areas and public or private services due to the introduction of new services such as advanced driving, advanced sensor and column movement. Accordingly, the disclosure proposes a way to classify V2X services, as shown in Table 1 below, based on the requirements and use cases for each service. The proposed table, as follows, refers to the 3GPP TR 22.886 “3GPP Support Extension Study for V2X 5G Services”.

[123] [Table 1]

[124]

Type Range Speed
transmission
data Usage Rel-14/15
V2X Public High Low BSM, CAM, DENM, P2X Advanced
driving Public Medium Medium A joint
use of information
for automated
driving.
Security Information
at the crossroads.
joint shift
traffic lanes, etc. extended
sensor Public Low
(neighboring
cars) High Motion
column Private/
public Average:
Front->
next,
next->
front
Low:
Next<->
next Medium

[125] FIG. 1E is a view illustrating V2X communication in a next generation mobile communication system to which the disclosure applies.

[126] V2X collectively refers to communication technology across all interfaces with a vehicle, and may include vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-pedestrian (V2P), vehicle-to-network (V2N) and the like, according to the form and components of communication. V2P and V2V generally follow the Rel-13 device-to-device (D2D) structure and operation.

[127] The base station 1e-01 can communicate with at least one vehicle terminal 1e-05, 1e-10 and a portable pedestrian terminal 1e-15 located in a cell 1e-02 supporting V2X. For example, vehicle terminal 1e-05 may perform cellular communication with base station 1e-01 using link 1e-30, 1e-35 from vehicle terminal to base station (Uu), and vehicle terminal 1e-05 may perform communication from device to device (D2D) using a direct connection of PC5 1e-20, 1e-25 with another vehicle terminal 1e-10 or portable pedestrian terminal 1e-15.

[128] For the vehicle terminal 1e-05 and the other vehicle terminal 1e-10, or the vehicle terminals 1e-05 and 1e-10 and the pedestrian mobile terminal 5c-15 to directly transmit and receive information using direct connections 1e-20 and 1e-25, the base station needs to allocate a pool of resources that can be used for sidelink communication. According to how the base station allocates resources to the terminal, the allocation can be divided into scheduled resource allocation (mode 3) and autonomous UE resource allocation (mode 4).

[129] Scheduled resource allocation is a method in which a base station allocates resources used to transmit a direct connection to RRC-connected terminals in a dedicated scheduling scheme. The above method is effective for interference control and resource pool management (dynamic allocation, semi-persistent transfer) because the base station can manage direct connection resources. In addition, in the case of scheduled resource allocation (mode 3), in which the base station allocates and manages resources for V2X, when the RRC connected terminal has data to be transmitted to other terminals, the terminal may request resource allocation from the base station using an RRC message. or a MAC control element (hereinafter referred to as "CE"). Here, the RRC message may be a SidelinkUEInformation or UEAssistanceInformation message. Meanwhile, the MAC CE may, as an example, be a New Format Buffer Status Report MAC CE (including at least a pointer indicating a buffer status report for V2P communication and size information buffered for D2D communication). For the detailed format and contents of the buffer status report used in 3GPP, see 3GPP Standard TS36.321 3GPP "E-UTRA MAC Protocol Specification".

[130] On the other hand, UE autonomous resource allocation is a method in which the base station provides a direct connection transmission/reception resource pool for V2X to the terminal as system information, and the terminal selects the resource pool according to a predetermined rule. The resource selection method may include area mapping, probing-based resource selection, and random selection regardless of service or service type.

[131] The resource pool structure for V2X may be configured in a manner in which resources 1e-40, 1e-50, 1e-60 for scheduling distribution (SA) and resources 1e-45, 1e-55, 1e-65 for data transmission are adjacent to each other to form one subchannel, or resources 1e-70, 1e-75, 1e-80 for SA and resources 1e-85, 1e-90, 1e-95 for data transmission are not contiguous. Regardless of which of the above two structures is used, a resource for an SA consists of two consecutive PRBs and includes information indicating the location of the resource for data transmission. The number of terminals receiving the V2X service in one cell may be multiple, and the relationship between base station 1e-01 and terminals 1e-05, 1e-10, and 1e-15 described above may be extended and applied.

[132] FIG. 1F is a view illustrating a procedure for monitoring and transmitting data of a V2X terminal operating in Mode 3 when a pool of service-specific resources and a pool of service-indifferent resources coexist in a next generation mobile communication system.

[133] With reference to FIG. 1F, an application server (hereinafter, V2X application server) 1f-05 provides V2X communication parameter information to terminals 1f-01, 1f-02 (1f-10). Alternatively, the control function (hereinafter, V2X control function) (1f-04) may receive parameter information from the V2X application server 1f-05 and provide parameter information for V2X communication to terminals 1f-01, 1f-02 (1f-10).

[134] The provided parameter may include V2X service mapping information and layer-2 identifiers (IDs) of the destination. For example, since the next generation mobile communication system needs to support new V2X services such as column movement, advanced driving, advanced sensors, etc., the new V2X services can be mapped to layer-2 identifiers (IDs) of the destination through an identifier such as service provider identifier (PSID), intelligent transportation system application identifiers (ITS-AID), or new V2X application identifiers.

[135] In addition, the provided parameters may include mapping information of V2X frequencies (hereinafter, V2X frequencies) and V2X services, or V2X frequencies and V2X service types (e.g., PSID, or ITS-AID, or new identifiers specified above) , or V2X frequencies and Radio Access Technology (RAT). Here, the V2X frequencies may represent the V2X LTE frequency and/or the V2X NR frequency, and thus the radio access technology may also represent E-UTRA and/or NR.

[136] In addition, the display information specified above may further include information about the geographic area(s). For example, in a particular geographic area, V2X frequencies may not be available due to local restrictions, and in a geographic area where privacy is a concern, the list of available V2X services or types of V2X services may differ, so that geographic area information may be included together in the provided parameter.

[137] In addition, the provided parameter may include V2X service mapping information and a communication range or a transmission range.

[138] In addition, the provided parameters may include mapping information about per-packet near-range service priority (prose) (PPPP) and packet delay budget, or V2X and PPPP service mapping information, or V2X and per-packet service mapping information. reliability prose (PPPR) for V2X communication.

[139] The provided parameter may include all of the information described above, or at least one of the information described above.

[140] The terminals 1f-01 and 1f-02 preconfigure the parameters initially provided from the V2X application server 1f-05 or the V2X control function 1f-04.

[141] If the terminal 1f-01 having the previously configured parameters mentioned above is interested in a specific V2X service x, the terminal searches for a suitable cell to bind by performing a selection or a selection procedure. In addition, terminal 1f-01 binds in cell (1f-15). In this case, the terminal can find a cell to anchor on the V2X frequency supported by the public home land mobile network (HPLMN) to which the specific V2X service x is mapped. Terminal 1f-01 anchoring in a cell may receive (1f-20) SIB21 from base station 1f-03.

[142] The system information (1f-20) may include at least one of service-individual resource pool information on the serving frequency for signal transmission and reception, and service-indifferent resource pool information, inter-frequency individual resource pool information, for resource services and service-indifferent resource pool information, service-indifferent resource inter-RAT pool information and service-indifferent resource pool information, timing configuration information, zone configuration information for a terminal to autonomously select a resource and transmit data, and LTE/NR uplink and downlink priority (PC5) and uplink and downlink (Uu) configuration information.

[143] The service-specific resource pool information may specifically include information about the radio access technology (E-UTRA or NR) that can be supported in the resource pool for each service, information about displayed services (for example, a list of V2X services displayed with combination of link domain, transport domain, PPPP, PPPR, and destination layer-2 ID), resource pool configuration information (e.g., time domain resource in bitmap format, frequency domain resource, subcarrier spacing information, or cyclic prefix length when NR is supported) , transmit power configuration information including the maximum allowed transmit power, and configuration information for the sounding operation.

[144] The service indifferent resource pool information does not include mapped service information, and may include the radio access technology information specified above, resource pool configuration information, transmission power configuration information, and configuration information for a sounding operation.

[145] The terminal 1f-01 receiving system information can determine frequencies/RATs monitored for V2X communication (1f-25). In this case, the terminal may determine frequencies/RATs to be monitored based on a set of two categories.

[146] The first set (1st Monitored Frequency/RAT Set, or First Resource Set) may include an intersection of frequencies specified for V2X support in system information or an RRC message (e.g., an RRC Connection Reconfiguration message) and frequencies mapped with V2X services considered by the terminal.

[147] The second set (2nd controlled frequency/RAT set or second resource set) may include intra-RAT frequencies/inter-RAT frequencies providing a pool of service-specific resources to support a particular V2X service x.

[148] The terminal first monitors a second set of resource pools for each service. If there are no frequencies supporting a specific V2X service x in the resource pool for each service, the terminal controls the resource pool irrelevant to the service included in the first set.

[149] When data traffic is generated for a specific V2X service x (1f-30), the terminal performs an RRC connection with the base station (1f-35). In the above RRC connection process, the terminal can transmit an RRC message by adding information about a specific V2X service x to the base station. The RRC connection process may be performed before data traffic is generated for a particular V2X service x (1f-30).

[150] When there is a service-unique resource pool that supports a particular V2X service x on a serving frequency, terminal 1 1f-01 requests transmission resources from base station 1f-03 for V2X communication with other terminals 1f-02 or base station 1f- 03 using a service-specific resource pool (1f-40). In this case, the terminal may request transmission resources using an RRC message or a MAC control element (CE).

[151] Here, as the RRC message, a SidelinkUEInformation or UEAssistanceInformation message can be used. Meanwhile, the MAC CE may be, as an example, a new format MAC CE buffer status report (including at least a pointer indicating this buffer status report for V2X communication and size information buffered for D2D communication).

[152] The base station 1f-03 may allocate the V2X transmission resource to the terminal 1 (1f-01) (1f-45). The base station 1f-03 may allocate V2X transmission resources via a dedicated RRC message, and the message may be included in the RRCConnectionReconfiguration message.

[153] The resource allocation may be a V2X resource scheduled from the base station via the Uu interface according to the type of traffic requested by the terminal, link congestion, or V2X service, or may be a resource selected directly by the terminal from a pool of resources provided from the base station. stations (resource for PC5). To determine resource allocation, the terminal may add and transmit PPPP or PPPR or LCID information of V2X traffic via UEAssistanceInformation or MAC CE. Since the base station also knows information about resources used by other terminals, the base station schedules the resource requested by terminal 1 among the remaining resources.

[154] In addition, when the RRC message (RRCConnectionReconfiguration message) includes SPS configuration information via Uu, the base station can activate SPS by transmitting DCI via PDCCH (1f-50).

[155] Terminal 1 1f-01 may select a transmission line and resource according to the resource and transmission method allocated from base station 1f-03 (1f-55), and transmit data to terminals 1f-02 or base station 1f-03 (1f-60).

[156] If there is no service-specific resource pool that supports the specific V2X service x on the serving frequency, but there is a service-unique resource pool that supports the specific V2X service x on the non-serving frequency, terminal 1 1f-01 requests a transmission resource, capable of V2X communication with other terminals 1f-02 or base station 1f-03, from base station 1f-03 (1f-40). In this case, the terminal may request a transmission resource using an RRC or MAC CE message.

[157] Here, the RRC message may be a SidelinkUEInformation or UEAssistanceInformation message. Meanwhile, the MAC CE may be, as an example, a new format MAC CE buffer status report (including at least a pointer indicating this buffer status report for V2X communication and size information buffered for D2D communication).

[158] The base station 1f-03 may allocate the V2X transmission resource to the terminal 1 1f-01 (1f-45). The base station 1f-03 may allocate V2X transmission resources via a dedicated RRC message, and the message may be included in the RRCConnectionReconfiguration message.

[159] The resource allocation may be a V2X resource scheduled from the base station via the Uu interface according to the type of traffic requested by the terminal, link congestion, or V2X service, or may be a resource directly selected by the terminal from a pool of resources provided from the base station. stations (resource for PC5). To determine resource allocation, the terminal may add and transmit PPPP or PPPR or LCID information of V2X traffic via UEAssistanceInformation or MAC CE. Since the base station also knows information about resources used by other terminals, the base station can schedule the resource requested by terminal 1 among the remaining resources.

[160] In addition, when the RRC message (RRCconnection reconfiguration message) includes SPS configuration information via Uu, the base station can activate SPS by transmitting DCI via PDCCH (1f-50). Terminal 1 1f-01 may select the transmission line and resource according to the resource and transmission method allocated from the base station 1f-03 (1f-55), and transmit data to the terminals 1f-02 or to the base station 1f-03 (1f-55). 60).

[161] FIG. 1G is a view illustrating a data transmission procedure of a V2X terminal operating in Mode 4 when a pool of service-specific resources and a pool of service-indifferent resources coexist in a next generation mobile communication system.

[162] With reference to FIG. 1G, the V2X application server 1g-05 may provide parameter information for V2X communication to terminals 1g-01 and 1g-02 (parameter provision) (1g-10). Alternatively, the V2X control function (1g-04) may receive parameter information from the V2X application server 1g-05 and provide parameter information for V2X communication to terminals 1g-01, 1g-02 (1g-10).

[163] The provided parameter may include V2X service mapping information and a layer-2 ID of the destination. For example, in the next generation mobile communication system, new V2X services such as platooning, advanced driving, advanced sensors, etc. must be supported. Therefore, a new V2X service can be mapped to a layer-2 destination ID via an identifier such as PSID or ITS-AID or new V2X application identifiers.

[164] In addition, the provided parameters may include mapping information of V2X frequencies and V2X services or V2X frequencies and V2X service types (e.g., PSID or ITS-AID or new identifiers specified above) or V2X frequencies and radio access technology (RAT) . Here, the V2X frequencies may represent the V2X LTE frequency and/or the V2X NR frequency, and thus the radio access technology may also represent E-UTRA and/or NR.

[165] In addition, the mapping information specified above may further include information about the geographic area(s). For example, in a particular geographic area, the use of V2X frequencies may not be possible due to local restrictions, and in a geographic area where privacy is an issue of particular concern, the list of available V2X services or types of V2X services may differ, so information about the geographic area may be included. to the provided parameters.

[166] In addition, the provided parameter may include V2X service mapping information and a communication range or a transmission range.

[167] In addition, the provided parameters may include PPPP mapping information and packet delay budget, V2X and PPPP service mapping information, or V2X and PPPR service mapping information for V2X communication.

[168] The provided parameter may include all of the information described above, or at least one of the information described above.

[169] The terminals 1g-01 and 1g-02 may preconfigure the parameters initially provided from the V2X application server 1g-05 or the V2X control function 1f-04.

[170] There is a difference in that, unlike mode 3, in which the base station 1g-03 is directly involved in resource allocation, in operation mode 4, terminal 1 1g-01 can autonomously select resources and transmit data, based on the pool resources previously received through system information.

[171] The disclosure proposes that base station 1g-03 in V2X communication allocates a pool of service-specific direct connection resources and a pool of service-indifferent direct connection resources for terminal 1 1g-01. A terminal interested in a particular V2X service x can autonomously select an available resource pool after probing the resources used by other neighboring terminals from the direct connection resource pool for each service. Alternatively, the terminal may randomly select a resource from a preconfigured resource pool.

[172] In addition, a terminal that intends to transmit/receive information irrelevant to a service type can autonomously select an available resource pool after probing resources used by other neighboring terminals from a direct connection service-indifferent resource pool. Alternatively, the terminal may randomly select a resource from a preconfigured resource pool.

[173] Terminal 1 1g-01, having the preconfigured parameters described above, may perform a selection or a selection procedure when interested in a particular V2X service x to find a suitable cell for anchoring. Then, terminal 1g-01 binds to cell (1g-15). Here, the terminal can find a cell to anchor on the V2X frequency supported by the HPLMN mapped to the specific V2X service x. Terminal 1 1g-01, after binding, can receive (1g-20) SIB21 from base station 1g-03.

[174] The system information (1g-20) may include at least one of service-specific resource pool information on the serving frequency for signal transmission and reception, service-indifferent resource pool information, service-specific resource pool information and information about the inter-frequency pool of service indifferent resources, information about the pool of service indifferent resources, information about the pool of individual service resources and information about the inter-RAT pool of service indifferent resources, synchronization configuration information, zone configuration information for the terminal, to autonomously select resources and transmit data, LTE/NR direct connection priority (PC5) and uplink and downlink (Uu) configuration information.

[175] The service-specific resource pool information may specifically include information about the radio access technology (E-UTRA or NR) that can be supported in the resource pool for each service, mapped service information (e.g., a list of V2X services mapped with combination of link domain, transport domain, PPPP, PPPR, and destination layer-2 ID), resource pool configuration information (e.g., time domain resource in bitmap format, frequency domain resource, subcarrier spacing information, or cyclic prefix length when NR is supported) , transmit power configuration information including the maximum allowed transmit power, and configuration information for the sounding operation.

[176] The service indifferent resource pool information does not include mapped service information, and may include the radio access technology information specified above, resource pool configuration information, transmission power configuration information, and configuration information for a sounding operation.

[177] Terminal 1 1g-01 receiving system information can determine frequencies/RATs monitored for V2X communication (1g-25). In this case, terminal 1 1g-01 may determine the monitored frequencies/RAT based on a set of two categories.

[178] The first set (1st controlled frequency/RAT set or first resource set) may include an intersection of frequencies specified for V2X support in system information or an RRC message (eg, an RRC connection reconfiguration message) and frequencies mapped with V2X services considered by the terminal.

[179] The second set (2nd set of controlled frequencies/RAT, or second set of resources) may include intra-RAT frequencies/inter-RAT frequencies providing a pool of service-specific resources to support a specific V2X service x.

[180] The terminal first monitors the second set of the resource pool for each service. If there are no frequencies supporting a specific V2X service x in the resource pool for each service, the terminal controls the resource pool irrelevant to the service included in the first set. If the terminal 1 1g-01 does not receive the system information or the RRC message, the terminal can perform the above operation based on the preconfigured information from the V2X control function 1g-04 or the V2V application server 1g-05.

[181] When data traffic for a particular V2X service x is generated (1g-30), terminal 1 1g-01 may select a resource in the time/frequency domain (1g-35) and transmit data to at least one other terminal 1g-02 according to the configuration information (e.g., transfer operation (one dynamic allocation transfer, multiple dynamic allocation transfers, one probe-based transfer, multiple probe-based transfers, random transfer) configured for a pool of service-specific resources for a specific V2X service x ) received from base station 1g-03 via system information (1g-40).

[182] In mode 4 of operation, for multiple probe-based transmission, the terminal may probe resources for signaling from other terminals, select a resource block to be transmitted from a resource pool in which the corresponding transmission is performed, and then reserve resources to be periodically transmitted. Thereafter, if the data packet generated by the terminal changes or disappears, the terminal restarts or cancels the above-described probe and resource reservation operation so that a new data packet can be delivered.

[183] As described above, multiple transmission based on probing and reserving resources can be triggered in a basic manner, and if the probing operation does not give a good result, communication can be performed through random selection of resources from the corresponding resource pool. If the terminal does not receive the system information or the RRC message, the above-described operation is performed based on the preconfigured information from the V2X control function 1g-04 or the V2V application server 1g-05.

[184] FIG. 1H is a view illustrating a block configuration of a terminal according to the disclosure.

[185] As illustrated in FIG. 1H, a terminal according to an embodiment of the disclosure includes a transceiver 1h-05, a controller 1h-10, a multiplexer and demultiplexer 1h-15, an upper layer processor 1h-20 and 1h-25, and a control message processor 1h-30.

[186] The transceiver 1h-05 receives the data and the predetermined control signal via the forward channel of the serving cell, and transmits the data and the predetermined control signal via the reverse channel. When the plurality of serving cells are configured, the transceiver 1h-05 performs data transmission/reception and control signal transmission/reception through the plurality of serving cells. The multiplexer and demultiplexer 1h-15 multiplexes the data generated by the upper level processors 1h-20 and 1h-25 or the control message processor 1h-30, or transmits the data received from the transceiver 1h-05 to be transmitted to the appropriate processor 1h-20 and 1h -25 upper level or processor 1h-30 control messages. The control message processor 1h-30 transmits and receives the control message from the base station and takes the necessary action. The action includes a function of processing control messages such as RRC and MAC CE messages, reporting CBR measurement values, and receiving RRC messages for resource pool and terminal operation. Upper processors 1h-20 and 1h-25 are DRB devices and can be configured for each service. Upper layer processors 1h-20 and 1h-25 process data generated from user services such as File Transfer Protocol (FTP) or Voice over Internet Protocol (VoIP) and deliver it to multiplexing and demultiplexing units (1h-15) or process data transmitted from the multiplexer and demultiplexer 1h-15, and transmit the processed data to the upper layer service application. The controller 1h-10 identifies the scheduling command received via the transceiver 1h-05, such as reverse grants, and controls the transceiver 1h-05 and the multiplexer and demultiplexer 1h-15 so that the reverse transmission is performed with the appropriate transmission resource at the appropriate time. Meanwhile, it has been described above that the terminal is composed of a plurality of blocks, and each block performs a different function, but this is only an exemplary embodiment and the disclosure is not limited thereto. For example, the controller 1h-10 may itself perform the function performed by the demultiplexer 1h-15.

[187] FIG. 1I is a block diagram showing the configuration of a base station according to the disclosure.

[188] The base station apparatus of FIG. 1i includes a transceiver 1i-05, a controller 1i-10, a multiplexer and demultiplexer 1i-20, a control message processor 1i-35, upper layer processors 1i-25 and 1i-30, and a scheduler 1i-15.

[189] The transceiver 1i-05 transmits data and a predetermined control signal via a forward carrier, and receives data and a predetermined control signal via a reverse carrier. When multiple carriers are configured, the transceiver 1i-05 performs data transmission/reception and control signal transmission/reception via the plurality of carriers. The multiplexer and demultiplexer 1i-20 multiplexes the data generated by the upper level processors 1i-25 and 1i-30 or the control message processor 1i-35, or demultiplexes the data received from the transceiver 1i-05 to transmit them to the appropriate processors 1i-25 and 1i -30 high, control message processor 1i-35 or controller 1i-10. The control message processor 1i-35 receives an instruction from the controller, generates a message to be transmitted to the terminal, and transmits the generated message to the lower layer. The upper layer processors 1i-25 and 1i-30 may be configured to, for each terminal-specific service, process data generated from user services such as FTP or VoIP and transmit the data to the multiplexing and demultiplexing unit 1i-20, or process the data transmitted from the multiplexer and demultiplexer 1i-20, and transmit the data to the upper layer service application. The scheduler 1i-15 allocates transmission resources to the terminal at an appropriate time based on the terminal's buffer status, channel status, and active time of the terminal, and processes the signal transmitted by the terminal to the transceiver or transmits the signal to the terminal.

[190] In the specific embodiments of the disclosure described above, the constituent elements included in the disclosure are expressed in singular or plural in accordance with the specific embodiment presented. However, the singular or plural expression is appropriately chosen in the situation presented for convenience of description, and the disclosure is not limited to singular or plural constituents, and even plural constituents may consist of a single component. Even a plural component may consist of a single component, or even a singular component may consist of a plurality.

[191] Meanwhile, although specific embodiments have been described in the detailed description of the disclosure, various modifications can be made without deviating from the scope of the disclosure. Therefore, the scope of the disclosure should not be limited to the described embodiments, but should be determined by the scope of the claims described later, as well as the scope and equivalents of the claims.

[192] In addition, the disclosure may be summarized as follows.

[193] 1. Defining a pool of service-specific resources to support a variety of V2X R16 services, both serving cell and inter-frequency.

[194] 2. Coexistence of a pool of resources individual for services and a pool of resources indifferent to services.

[195] 3. V2X service classification based on PPPP, range, PPPR, Prose L2 ID, or a combination of the information above.

[196] In addition, the disclosure may be summarized as follows.

[197] 1. UE <- V2X server: Providing parameters

[198] - Layer-2 ID mapping information of destination and V2X service, such as PSID, ITS-AID, ES, convoy...

[199] - V2X/RAT (LTE and/or NR) service mapping information

[200] - Distance service mapping information (high, medium, low)

[201] - PPPP service mapping information

[202] - PPPR Service Mapping Information

[203] 2. UE interested in V2X service x: Binding to V2X HPLMN frequency mapped to service x

[204] 3. UE: Receiving V2X system information, V2X system information may include at least one of the following information.

[205] - Service Frequency

[206] -- Service-specific resource pools

[207] -- Pools of service-indifferent resources

[208] - Inter-Frequency

[209] -- Service-specific resource pools

[210] -- Pools of service-indifferent resources

[211] - Inter-RAT

[212] -- Service-specific resource pools

[213] -- Pools of service-indifferent resources

[214] - Service-Specific Resource Pools

[215] -- RAT information (optional; presented only if included in the inter-RAT branch)

[216] E-UTRA or NR

[217] -- Displayed Services

[218] list of displayed services

[219] Range, PPPP, L2 Destination ID, or combination

[220] -- Resource Pool Configuration

[221] Time Domain Resource: Bitmap

[222] frequency domain resource…

[223] SCS (if NR) and CP length)

[224] -- Transmit Power Configuration

[225] Maximum Transmit Power Allowed

[226] -- Resource Probing Options

[227] - Pool of Service Indifferent Resources

[228] -- RAT Information

[229] -- Resource pool configuration

[230] -- Transmit Power Configuration

[231] -- Resource Probing Options

[232] 4. Determination of frequencies/RAT for control

[233] - 1st Set of Monitored Frequencies/RAT:

[234] -- Intersection of frequencies to which the V2X service in question is mapped and frequencies indicated by the supporting V2X in the system information

[235] - 2nd Set of Monitored Frequencies/RAT:

[236] -- Intra-RAT frequencies/Inter-RAT frequencies providing a service-specific pool for service x

[237] - UE controls service-specific 2nd set pools

[238] - If none of the frequencies provides a service-specific pool for service x

[239] - UE controls 1st set service indifferent pools

[240] 5. Determination of Frequencies/RAT for Transmission

[241] - The UE transmits data for service X in the service-specific resource pool of a specific service X on the serving frequency (if supported) or on the non-serving frequency (if not supported by the serving frequency)

[242] <Second Embodiment>

[243] Next, the operation of the disclosure will be described in detail with reference to the accompanying drawings. In the following description of the disclosure, when it is determined that a detailed description of an associated known function or configuration may obscure the subject matter of the disclosure, their detailed description will be omitted. In addition, the terms to be described below are terms defined in view of the functions in the disclosure and may vary according to the intentions or habits of users and operators. Therefore, definitions of terms should be made based on the content in the entire specification. Terms for identifying an access node used in the present description, terms for network entities, terms for messages, terms for interfaces between network entities, terms relating to various identification information, and the like are used illustratively for convenience of description. Therefore, the disclosure is not limited to the terms below, and other terms may be used to refer to subjects having equivalent technical meanings.

[244] For the convenience of the description below, the disclosure uses the terms and denominations defined in the 3rd Generation Partnership Project Long Term Evolution (3GPP LTE) standards. However, the disclosure is not limited to these terms and denominations and may apply similarly to systems that conform to other standards.

[245] FIG. 2A is a view illustrating the structure of an LTE system, which is referred to to describe the disclosure.

[246] With reference to FIG. 2A, as illustrated, the radio access network of an LTE system is composed of next generation base stations 2a-05, 2a-10, 2a-15, 2a-20 (evolved Node B, hereinafter eNB, Node B or base station), MME 2a-25 and S-GW 2a-30. The user equipment (hereinafter UE or terminal) 2a-35 accesses the external network via eNB 2a-05 ~ 2a-20 and S-GW 2a-30.

[247] FIG. 2A, eNBs 2a-05~2a-20 correspond to the existing Node B of the UMTS system. The eNB is connected to the UE 2a-35 via a radio link and performs a more complex role than the existing Node B. a device for scheduling by collecting state information such as buffer status, available transmit power status, and channel status of the UE, and eNB 2a-05-2a-20 is responsible. One eNB typically manages multiple cells. For example, in order to realize a transmission rate of 100 Mbps, the LTE system uses, for example, an Orthogonal Frequency Division Multiplexing (OFDM) scheme in a bandwidth of 20 MHz as a radio access technology. In addition, an adaptive modulation coding (AMC) method is applied to determine a modulation scheme and a channel coding rate according to the channel state of the terminal.

[248] S-GW 2a-30 is a device that provides a bearer and generates or deletes a bearer under control of MME 2a-25. The MME is a device responsible for various management functions as well as mobility management functions for the terminal, and is connected to a plurality of base stations.

[249] FIG. 2B is a view illustrating the structure of a radio protocol in the LTE disclosure system.

[250] With reference to FIG. 2B, the structure of the radio protocol in the LTE system includes PDCP 2b-05 and 2b-40, RLC 2b-10 and 2b-35, and MAC 2b-15 and 2b-30 at the terminal and eNB, respectively. PDCP 2b-05 and 2b-40 are responsible for operations such as compression/recovery of the IP header. The main functions of PDCP are summarized below.

[251] - Header compression and decompression: ROHC only

[252] - User data transfer

[253] - Sequential delivery of the upper layer PDU in the PDCP re-establishment procedure for RLC AM

[254] - For split bearers in DC (support for RLC AM only): PDCP PDU routing for transmission and PDCP PDU reordering for reception

[255] - Low Layer SDU Duplication Detection in RLC AM PDCP Reset Procedure

[256] - Retransmission of PDCP SDU in handover and, for split bearers in DC, PDCP PDU in PDCP data recovery procedure, for RLC AM

[257] - Encryption and Decryption

[258] - Timer-based uplink SDU discard

[259] Radio Link Controls (RLC) 2b-10 and 2b-35 restore the PDCP PDU to the proper size and perform the ARQ operation. The main functions of the RLC are summarized below.

[260] - Upper Layer PDU Transfer

[261] - Error Correction via ARQ (for AM data transfer only)

[262] - RLC SDU Concatenation, Segmentation and Reassembly (for UM and AM data transfer only)

[263] - RLC PDU data re-segmentation (AM data transfer only)

[264] - RLC PDU data reordering (only for carrying UM and AM data)

[265] - Duplication Detection (only for UM and AM data transfer)

[266] - Protocol error detection (AM data transfer only)

[267] - Drop RLC SDU (for UM and AM data transfer only)

[268] - Reinstall RLC

[269] The MACs 2b-15 and 2b-30 are connected to multiple RLC layer entities configured in one UE, and perform an operation of multiplexing an RLC PDU into a MAC PDU and demultiplexing an RLC PDU from a MAC PDU. The main functions of the MAC are summarized below.

[270] - Mapping between logical channels and transport channels

[271] - Multiplexing/demultiplexing MAC SDUs belonging to the same or different logical channels to/from transport blocks (TB) delivered to/from the physical layer over transport channels

[272] - Reporting scheduling information

[273] - Error Correction via HARQ

[274] - Priority processing between logical channels of the same UE

[275] - Priority processing between UEs through dynamic scheduling

[276] - MBMS Service Identification

[277] - Transport format selection

[278] - Filling

[279] The physical layers 2b-20 and 2b-25 channel-code and modulate the upper layer data, convert it into OFDM symbols and transmit them to the radio channel, or demodulate the OFDM symbols received via the radio channel, channel-decode them and transmit them to the upper layer . In addition, the physical layer also uses hybrid ARQ (HARQ) for further error correction, and the receiving side transmits the reception of a packet transmitted by the transmitting side in 1 bit. This is called ACK/NACK HARQ information. Downlink ACK/NACK HARQ information for uplink transmission may be transmitted via a Physical Hybrid ARQ Indicator Channel (PHICH), and uplink ACK/NACK HARQ information for downlink transmission may be transmitted via a Physical Uplink Control Channel (PUCCH). ) or Physical Uplink Shared Channel (PUSCH).

[280] Meanwhile, the PHY layer may be composed of one or multiple frequencies/carriers, and a technology for simultaneously configuring and using multiple frequencies is called carrier aggregation technology (hereinafter referred to as “CA”). Through CA technology, only one carrier was used for communication between a terminal and a base station (E-UTRAN NodeB, eNB), but the transmission volume can be greatly increased by the number of subcarriers by additionally using the main carrier and one or more subcarriers. Meanwhile, in LTE, a cell in a base station using a primary carrier is called a primary cell (PCell), and a subcarrier is called a secondary cell (SCell).

[281] Although not shown in this figure, there is a radio resource control layer (hereinafter referred to as "RRC"), respectively, above the PDCP layer of the terminal and the base station, and the RRC layer can send and receive control messages related to access and measurements of the configuration to control radio resources.

[282] FIG. 2C is a view illustrating the structure of a next generation mobile communication system to which the disclosure applies.

[283] As illustrated with reference to FIG. 2C, the radio access network of the next generation mobile communication system is composed of a next generation base station (NR NB) 2c-10 and a NR CN 2c-05 (or a next generation core network (NG CN)). The user terminal (NR UE or terminal) 2c-15 accesses the external network via NR NB 2c-10 and NR CN 2c-05.

[284] FIG. 2c, NR NB 2c-10 corresponds to the eNB of the existing LTE system. The NR NB is connected to the NR UE 2c-15 via a radio channel and can provide a service superior to that of the existing Node B. In the next generation mobile communication system, since all user traffic is served through a shared channel, a device is required that collects and schedules status information such as such as buffer status, available transmit power status and channel status of the UE, and NR NB 2c-10 is responsible.

[285] One NR NB typically manages multiple cells. In order to realize ultra-high-speed data transmission compared to the existing LTE, it may have a higher than the existing maximum bandwidth, and an additional beamforming technology using orthogonal frequency division multiplexing (OFDM) may be introduced as a wireless access technology. In addition, an adaptive modulation coding (AMC) method is applied to determine a modulation scheme and a channel coding rate according to the channel state of the terminal.

[286] NR CN 2c-05 performs functions such as mobility support, bearer configuration, and QoS configuration. The NR CN is a device responsible for various management functions as well as a mobility management function for the terminal, and is connected to a plurality of base stations. In addition, the next generation mobile communication system can be interconnected with the existing LTE system, and the NR CN is connected to the MME 2c-25 via a network interface. The MME connects to the existing eNB 2c-30.

[287] FIG. 2D is a view illustrating the radio protocol structure of the next generation mobile communication system to which the disclosure applies.

[288] With reference to FIG. 2D, the radio protocol structure of the next generation mobile communication system consists of PDCP NRs 2d-05 and 2d-40, RLC NRs 2d-10 and 2d-35, and MAC NRs 2d-15 and 2d-30 at the terminal and NR base station, respectively. The main functions of the NR PDCP 2d-05 and 2d-40 may include some of the following functions.

[289] - Header compression and decompression: ROHC only

[290] - User data transfer

[291] - Sequential Delivery of Upper Layer PDUs

[292] - PDCP PDU Reordering for Receive

[293] - Low Layer SDU Duplication Detection

[294] - PDCP SDU Retransmission

[295] - Encryption and decryption

[296] - Timer-based uplink SDU discard

[297] In the above, the PDCP NR device reordering function refers to the function of reordering the PDCP PDUs received from the lower layer in order based on the PDCP sequence number (SN), may include the function of passing data to the upper layer in the reordering order, may include a function to reorder the order to record the lost PDCP PDUs, may include a function to report the status of the lost PDCP PDUs to the sender, and may include a function to request retransmission of the lost PDCP PDUs.

[298] The basic functions of the NR RLC 2d-10 and 2d-35 may include some of the following functions.

[299] - Upper Layer PDU Transfer

[300] - Serial Delivery of Upper Layer PDU

[301] - Inconsistent High Layer PDU Delivery

[302] - Error Correction via ARQ

[303] - RLC SDU Concatenation, Segmentation and Reassembly

[304] - RLC Data PDU Resegmentation

[305] - RLC Data PDU Reordering

[306] - Duplication Detection

[307] - Protocol Error Detection

[308] - Drop RLC SDU

[309] - RLC Reset

[310] In the above, the NR RLC device serial delivery function refers to the sequential delivery function of RLC SDUs received from the lower layer to the upper layer, may include a reassembly and delivery function when one RLC SDU is initially divided into a plurality of RLC SDUs. and received, may include a function of reordering received RLC PDUs based on an RLC sequence number (SN) or a PDCP sequence number (SN), may include a function of reordering and recording lost RLC PDUs, may include a function of reporting the status of lost RLC PDU to the transmission side, may include a function to request retransmission of lost RLC PDUs, may include a function of transferring only RLC SDU before the lost RLC SDU to the upper layer in order when there is a lost RLC SDU, may include a function of sequential delivery of all RLC SDUs received before the start of the timer to the upper layer, even if there is a loss the given RLC SDU if the predefined timer has expired, and may include a function to sequentially deliver all RLC SDUs already received to the upper layer, even if there is a lost RLC SDU if the predefined timer has expired. In addition, RLC PDUs can be processed in order of reception (regardless of the order of the serial number and sequence number, in order of arrival) and delivered to the PDCP device regardless of the order (non-sequential delivery), and in the case of a segment, the segments stored in the buffer or to be received in the future, may be received, reconstructed into a complete RLC PDU, processed, and delivered to the PDCP device. The NR RLC layer may not include a concatenation function, and the function may be performed in the NR MAC layer, or may be replaced by the NR MAC layer multiplexing function.

[311] In the above, the non-sequential delivery function of the NR RLC device refers to the function of directly delivering the RLC SDUs received from the lower layer to the upper layer regardless of the order, may include a reassembly and delivery function when one RLC SDU is initially divided into a plurality of RLC SDUs and received, and may include a function of storing the RLC SN or PDCP SN of the received RLC PDUs, sorting the order, and recording the lost RLC PDUs.

[312] NR MAC 2d-15 and 2d-30 may be connected to multiple NR RLC layer entities configured in one terminal, and the basic functions of the NR MAC may include some of the following functions.

[313] - Mapping between logical channels and transport channels

[314] - MAC SDU Multiplexing/Demultiplexing

[315] - Message scheduling information

[316] - Error Correction via HARQ

[317] - Priority processing between logical channels of the same UE

[318] - Priority processing between UEs through dynamic scheduling

[319] - MBMS Service Identification

[320] - Transport format selection

[321] - Filling

[322] NR PHY layers 2d-20 and 2d-25 may channel-code and modulate upper layer data, convert it to OFDM symbols and transmit it over the wireless channel, or may demodulate an OFDM symbol received over a radio channel, decode the channel, and transmit it on upper level.

[323] Although not illustrated in this figure, there is a radio resource control layer (hereinafter referred to as “RRC”), respectively, above the PDCP layer of the terminal and the base station, and the RRC layer transmits and receives control messages related to access and measurements of the configuration for radio resource control .

[324] FIG. 2E is a view illustrating V2X communication in a cellular deployment system.

[325] V2X collectively refers to a communication technology through all interfaces with a vehicle, and may include V2V, V2I, V2P, V2N, and the like according to the form and communication elements. V2P and V2V generally follow the Rel-13 Device-to-Device (D2D) framework and operation. That is, it is a direct connection (PC5) based operation, and actual data packets can be transmitted and received via a direct connection, which is a transmission channel between terminals rather than uplink and downlink of a base station and a terminal. This basic principle can apply not only to V2X defined in LTE, but also to V2X which can be redefined in NR and scenario-specific updates can be applied.

[326] The base station 2e-01 can communicate with at least one of the vehicle terminals 2e-05 and 2e-10 and the portable pedestrian terminal 2e-15 located in a cell 2e-02 supporting V2X. For example, vehicle terminal 2e-05 may perform cellular communication with base station 2e-01 using a vehicle terminal to base station link (Uu, 2e-30, 2e-35) and may perform device-to-device communication with another vehicle terminal 2e-10 or pedestrian portable terminal 2e-15 using PC5 2e-20 and 2e-25 direct connection.

[327] In the above, the base station may be an updated eNB supporting gNB or NR. In order for the vehicle terminals 2e-05 and 2e-10 and the pedestrian mobile terminal 2e-15 to directly transmit and receive information using a direct connection (2e-20, 2e-25), the base station must allocate a resource pool that can be used for direct connection. connections. The base station per terminal resource allocation method in V2X of the LTE system is described below, and a similar approach as in LTE can be applied in V2X introduced in the NR system. However, NR uses a different numerology and the direct connection resource pool structure may be slightly different.

[328] Based on the V2X of the LTE system, allocation can be divided into two types: scheduled resource allocation (mode 3) and autonomous UE resource allocation (mode 4) according to how the base station allocates resources to the terminal.

[329] Scheduled resource allocation is a method in which a base station allocates resources used to transmit a direct connection to RRC-connected terminals in a dedicated scheduling scheme. The method is effective for interference management and resource pool management (dynamic allocation, semi-persistent transfer) because the base station can manage direct connection resources. In addition, in the case of scheduled resource allocation (mode 3), in which the base station allocates and manages resources for V2X, when the RRC connected terminal has data to be transmitted to other terminals, the terminal may send a resource allocation request to the base station using the message RRC or Control Element (CE) MAC. Here, the RRC message may be a SidelinkUEInformation or UEAssistanceInformation message. Meanwhile, as an example of MAC CE, a new format MAC CE buffer status report (including at least an indicator indicating this buffer status report for V2X communication and data size information buffered for direct connection communication) can be used. Regarding the detailed format and contents of the buffer status report used in 3GPP, reference can be made to the 3GPP standard TS36.321 "E-UTRA MAC Protocol Specification".

[330] On the other hand, UE autonomous resource allocation is a method in which the base station provides a direct connection transmission/reception resource pool for V2X to the terminal as system information, and the terminal selects the resource pool according to a predetermined rule. The resource selection method may include zone mapping, probing-based resource selection, and random selection.

[331] The resource pool structure for V2X may be configured such that resources 2e-40, 2e-50, 2e-60 for scheduling distribution (SA) and resources 2e-45, 2e-55, 2e-65 for data transmission are adjacent to each other to form a single subchannel, or may be configured such that resources 2e-70, 2e-75, 2e-80 for SA and resources 2e-85, 2e-90, 2e-95 for data transmission are not contiguous . Regardless of which of the above two structures is used, a resource for an SA consists of two consecutive PRBs and includes information indicating the location of the resource for data transmission. The number of terminals receiving the V2X service in one cell may be multiple, and the relationship between the base station 2e-01 and the terminals 2e-05, 2e-10, 2e-15 described above may be expanded and applied.

[332] In addition, in order to transmit and receive direct connection data by the resource pool, the V2X service is mainly classified through a layer 2 destination ID (or destination ID) in the V2X of the LTE system. That is, the source/destination layer 2 ID (each 24 bits in size) is included in the header of the V2X data packet transmitted over the direct connection, that is, the MAC PDU, the source layer 2 ID means a unique terminal identifier, and the destination layer 2 ID indicates the service type of the V2X data traffic delivered by the terminal.

[333] If the other terminal that received the layer 2 ID of the destination transmitted by the transmission terminal has a subscription and is configured to receive the service for the corresponding layer 2 ID of the destination, the data packet belonging to the corresponding MAC PDU is decoded and delivered to the upper layer. The mapping information for the layer 2 ID of the destination and the V2X data packet is transferred from the V2X server to the V2X control function and provided to the terminal.

[334] FIG. 2F is a view illustrating a data transmission procedure of a V2X terminal operating in Mode 3 in an LTE system according to the disclosure.

[335] With reference to FIG. 2F, terminal 1 2f-01, after binding (2f-05), can receive system information (SIB21) for V2X from base station 2f-03 (2f-10).

[336] The system information may include at least one of resource pool information for transmitting/receiving direct connection data, configuration information for a sounding operation, information for configuring synchronization, and information for inter-frequency transmission/reception. When data traffic for V2X is generated in terminal 1 2f-01 (2f-15), an RRC connection with the base station can be performed (2f-20). The RRC connection process may be performed before data traffic is generated (2f-15).

[337] Terminal 1 2f-01 requests a transmission resource capable of V2X communication with other terminals 2f-02 from the base station (2f-25). At this time, the base station may be requested using an RRC message or a MAC CE. Here, the RRC message may be a SidelinkUEInformation or UEAssistanceInformation message. Meanwhile, as an example, the MAC CE may be a new format MAC CE buffer status report (including at least a pointer indicating this buffer status report for V2X communication and size information buffered for direct connection communication).

[338] The base station 2f-03 allocates the V2X transmission resource to the terminal 1 (2f-01) (2f-30). The base station 2f-03 may allocate V2X transmission resources via a dedicated RRC message, and the message may be included in the RRCConnectionReconfiguration message.

[339] The resource allocation may be a V2X resource scheduled from the base station via the Uu interface according to the type of traffic requested by the terminal, or depending on the congestion of the corresponding link, or the resource is directly selected by the terminal from the resource pool (resource for PC5), provided by the base station. To determine resource allocation, the terminal may add and transmit PPPP or logical channel identifier (LCID) information of V2X traffic via UEAssistanceInformation or MAC CE. Since the base station also knows information about the resources used by other terminals, the base station schedules the resource requested by the terminal 1 2f-01 among the remaining resources.

[340] In addition, when the RRC message includes SPS configuration information via Uu, the base station may activate SPS by transmitting DCI via PDCCH (2f-35). Terminal 1 2f-01 may select a transmission line and resource according to the resource and transmission method allocated from base station 2f-03 (2f-40) and transmit data to terminals 2f-02 (2f-45).

[341] FIG. 2G is a view illustrating a data transmission procedure of a V2X terminal operating in mode 4 according to the disclosure.

[342] Unlike mode 3, in which the base station (2g-03) is directly involved in resource allocation, there is a difference in that, in mode 4 operation, terminal 1 2g-01 autonomously selects resources and transmits data based on the resource pool, previously received through system information.

[343] In V2X communication, base station 2g-03 may allocate several types of direct connection resource pools (V2V resource pool, V2P resource pool) to terminal 1 2g-01. The resource pool may be composed of a resource pool in which the terminal can autonomously select an available resource pool after probing the resources used by other terminals around it, and a resource pool in which the terminal randomly selects a resource from a preconfigured resource pool.

[344] With reference to FIG. 2G, terminal 1 2g-01, after binding (2g-05), can receive system information SIB21 for V2X (2g-10) from base station 2g-03.

[345] The system information may include at least one of resource pool information for signal transmission/reception, configuration information for a sounding operation, timing configuration information, and information for inter-frequency transmission/reception.

[346] When data traffic for V2X is generated (2g-15) at 2g-01 terminal 1, 2g-01 terminal 1 may select a resource in the time/frequency domain (2g-20) and transmit data to other 2g-02 terminals according to with the configuration information (transmission operation configured for the resource pool (Dynamic Allocation Single Transmission, Dynamic Allocation Multiple Transmission, Probe-based Transmission Single, Probe-Based Multiple Transmission, Random Transmission)) received via system information from the base station 2g-03 ( 2g-25).

[347] In general, since the V2X service in LTE is implemented for the purpose of periodically transmitting location information of security-related terminals, the terminal can perform multiple transmission based on mode 4 sounding. That is, the terminal can probe resources through which signals are transmitted by other terminals, select a resource block to transmit in the resource pool in which the corresponding transmission is performed, and reserve resources so that they can be transmitted periodically thereafter. Thereafter, if the data packet generated by the terminal changes or disappears, the terminal restarts or cancels the above-mentioned probe and resource reservation operation so that a new data packet can be delivered. As described above, multiple transmission based on probing and reserving resources can be driven in a basic manner, and if the probing operation does not give a good result, communication can be performed through random selection of resources from the corresponding resource pool.

[348] FIG. 2F and FIG. 2G above briefly outlines the configuration and overall operation of sending and receiving direct connection data in the V2X system, and the packet structure, radio bearer configuration, and user plane encryption method for actually transmitted data packets are briefly described in FIG. 2E, or some of them are omitted. To redefine an NR V2X system, it may be necessary to redefine not only the full resource pool configuration, but also the user plane packet structure, the radio bearer configuration, and the encryption method. In the disclosure, a user plane operation and a complete radio bearer administration operation for NR V2X are proposed in the following embodiment.

[349] FIG. 2H is a view illustrating the MAC PDU format applied to the NR V2X system proposed in the disclosure.

[350] In addition to the LTE V2X system, the NR V2X system mainly assumes data transmission and reception between a terminal and a terminal as a base scenario. To this end, a definition of a direct connection other than the existing cell-oriented uplink and downlink, and the data transmission/reception format over the corresponding direct connection should be defined. When the V2X data packet is actually generated at the terminal, the MAC is configured to transmit the MAC PDU via the internal PDCP and RLC operation. In general, the RLC and PDCP operations will follow the operation defined in LTE or NR without change, and the configuration of the actually transmitted MAC PDU according to the direct connection needs to be applied.

[351] The disclosure proposes a transmission format of the NR V2X system, specifically a MAC PDU delivered over a direct connection, and MAC PDUs are broadly classified into a MAC PDU header, a MAC PDU subheader, and a MAC SDU.

[352] First, as can be seen in 2h-05-2h-50, the disclosure proposes the structure: MAC PDU header+m × (MAC PDU sub-header+MAC SDU) as the complete MAC PDU structure. Here, m denotes the total number of MAC SDUs with an associated subtitle transmitted by the MAC PDU, and unlike the LTE V2X system, the associated MAC subtitle is located before the MAC SDU for each MAC SDU. For reference, in the LTE V2X system, the MAC PDU has the structure: MAC PDU header+m × MAC PDU subheader+m × MAC SDU. In addition, optionally, a padding byte may be included to negotiate the size of the MAC PDU.

[353] Through the above structure of the MAC PDU, the MAC PDU received by the terminal can be sequentially processed at the same time as it is decoded, thereby having an advantage in data processing having high speed and high data rate. At present, LTE V2X data traffic only supports security-related services, including 300 bytes of location information, and NR supports various services, especially advanced driving, advanced sensor, convoy, and so on, so NR V2X requires a higher speed. data transmission than LTE V2X. Therefore, the MAC PDU structure proposed above may be useful for high-speed data processing.

[354] Specifically, considering in detail the MAC PDU header structure in V2X NR proposed by the present disclosure, the MAC PDU header has a V/R/SRC/DST structure.

[355] Here, the 2h-55 V field is a field indicating the version of the corresponding MAC PDU, and may be 4 bits. The V field is a field that distinguishes between Rel-12/13 D2D and Rel-14/15 V2X and the newly defined NR V2X. The V field may have a different value from the previous Rel-12/13 D2D and Rel-14/15 V2X, and the terminal receiving it may decode the corresponding field to identify the destination and method for which the MAC PDU was delivered.

[356] Field 2h-60 R of the MAC PDU header is a bit reserved for additional functions that can be used later.

[357] The SRC field 2h-65 of the MAC PDU header indicates a terminal source layer-2 ID of 24 bits and is mapped to a unique ID specified for each terminal. The corresponding SRC field may be updated and applied when the terminal receives a V2X related parameter from the V2X server, and may be recorded and applied in the terminal's own USIM.

[358] The DST field 2h-70 of the MAC PDU header indicates a layer-2 ID of the destination of 24 bits and may be mapped to distinguish which service is intended for each V2X service. In other words, having the same DST value means that the same V2X service is being delivered. However, since NR V2X is not broadcast-only, the 24-bit DST may be configured as a unique terminal ID to support unicast, or the terminal may be specified by some bits of the 24-bit DST. For example, in 24-bit DST, 16 MSBs may indicate a service type, and 8 LSBs may indicate a terminal ID. DST may be provided through the V2X server and V2X control function, or may be written to the USIM inside the terminal.

[359] Additionally, the NR subheader structure of the V2X MAC PDU may have an R/F/LCID/L structure.

[360] The MAC PDU subheader may be used to indicate the size of the MAC SDU to be transmitted. Fields 2h-75 and 2h-95 R of the MAC PDU subheader are bits reserved for additional functions that can be used later.

[361] The F fields 2h-80 and 2h-100 of the MAC PDU header may serve to indicate the size of the consecutive L fields 2h-90 and 2h-110, if the F field is configured as 0, this may mean that the L field is 8 bits (2h -90), and when the F field is configured as 1, the L field may mean 16 bits (2h-110). Alternatively, it may be configured the other way around.

[362] In addition, the LCID fields 2h-85 and 2h-105 of the MAC PDU subheader are values for classifying the logical channel type of the transmitted MAC SDU, and according to the SL data type, can be mapped and arranged in a table. The LCID is defined in the terminal, and the terminal may assign the generated V2X traffic to be mapped to the specific LCID.

[363] FIG. 2I is a view illustrating direct connection radio bearer administration, encryption, and decryption methods applied to the NR V2X system of the disclosure.

[364] If the direct connection radio bearer in V2X NR is defined as a direct connection resource bearer (SLRB), the SLRB may consist of a PDCP entity and an RLC entity. That is, SLRB=PDCP entity+RLC entity. In this case, one SLRB may be split into a pair of LCID and SRC/DST. That is, the terminal can set a new SLRB upon receiving an unknown LCID or an SRC/DST pair by decoding the contents included in the header and subheader of a MAC PDU packet received from another terminal. The operation of setting a new SLRB refers to the operation of initializing the PDCL/RLC objects constituting the SLRB, and the values of the state/timer variables may be initialized. Specifically, initialization may be performed according to the following procedure.

[365] 1. Configure T_reassembly (RLC) and T_reordering (PDCP) to 0 (This means reconfiguring the timer for reassembly and reordering in RLC and PDCP.)

[366] 2. Configuring RLC state variables (Since it is possible to receive data from other terminals in V2X, it is necessary not to configure the RLC SN received from the terminal to 0, but to be based on the RLC SN value of the first received packet.)

[367] A. RX_Next_Reassembly is configured based on the SN of the first received segment.

[368] B. RX_Next_Highest is configured based on the SN of the first received segment.

[369] In this case, the terminal may configure based on the RLC SN value received as described above, in the case of performing V2X communication via broadcast, wherein, in the case of performing V2X communication via unicast, the configuration method can be used as 0.

[370] 3. Configuring PDCP Status Variables

[371] A. RX_NEXT is configured based on the SN of the PDCP PDU that is received first.

[372] B. RX_DELIV is configured based on the SN of the first received PDCP PDU.

[373] RX_NEXT indicates the PDCP SN that is expected to be received next. The initial value can be configured as 0.

[374] RX_DELIV indicates a PDCP SDU that has not been delivered to the upper layer but is awaiting transmission, and the initial value may be configured as 0.

[375] In LTE, since there is no reordering function at the PDCP layer, received packets can be processed regardless of the SN. In this case, the reordering feature means that packets received from PDCP are processed in order and delivered to the upper layer. On the other hand, the disclosure proposes a method for configuring PDCP state variables as described above with respect to reordering in PDCP.

[376] At this time, similar to the RLC state variable above, the terminal can be configured based on the value of the received PDCP SN when performing V2X communication via broadcast, and in the case of V2X communication via unicast, the configuration method as 0 can be used.

[377] In addition, in the V2X service, since the service changes according to the L2 destination ID (DST ID), an encryption method is required that prevents a terminal without the right to the corresponding service from decoding the corresponding data. For example, an SLRB is transmitted for each specific service, and the corresponding SLRB has a root key for encryption for each DST ID. In this case, a valid key for encryption is generated as a root key characterized by a DST ID, and additional information required for the valid key may be included in the PDCP header. As a consequence, different passwords may be applied for each terminal and message (service). A more detailed operation follows the following procedure.

[378] The V2X NR terminal 2i-01 may perform a procedure for receiving a service right through the V2X control function 2i-02 to support the V2X NR service (2i-05).

[379] In the above procedure, the V2X control function (2i-02) performs parameter provisioning for the V2X NR service, and may transmit the DST ID mapping for each service, the V2X service supported for each RAT, frequency information supported by V2X, and the like. . The V2X control function (2i-02) receives and receives the corresponding information through the V2X server (2i-03) in advance, and when the corresponding terminal tries to connect, it sends the corresponding information to the terminal.

[380] Thereafter, the terminal performs a key request to the V2X server for each group (here, a group may be specified for each DST ID) (2i-10), and the V2X server provides a service key for each DST ID/group (2i-15) . As set forth above, the V2X server providing the key may be a V2X key administration function that may exist inside or outside the V2X server. In the disclosure, for convenience, it is described as a V2X server.

[381] In addition, in step 2i-20, the V2X server performs a root key provision procedure. That is, the root key extracted from the DST ID is assigned to the terminal, and the terminal can generate (or derive) an encryption key used for actual encryption by applying the DST ID to the root key. In the above step, the V2X server may also provide the terminal with an expiration time until which the key is applied.

[382] When the V2X data is generated, the terminal performs an exclusive logical operation (2i-35) on the key stream block obtained through the key generation algorithm (2i-30) to encrypt the terminal and the clear V2X data block to generate an encrypted user packet.

[383] Here, the encryption key stream block can be obtained after executing the key generation algorithm in which the user plane encryption key obtained from the root key (Key_V2X) (2i-25) and encryption parameters such as COUNT (Count) (for example, part of the PDCP SN+ID Key), Bearer (Bearer ID), Direction (direction of message delivery, 0 or 1) and Length (Length) (length of the key stream block) are entered as inputs.

[384] The receiving terminal receives the encrypted user data packet, performs the same key generation algorithm used by the terminal, generates the same key stream block as used for encryption, and performs an exclusive logic operation (2i-45). Similar to the execution of the algorithm in the terminal, in the receiving terminal (or as applied to the base station), the encryption key stream block can be obtained by inputting the user plane encryption key obtained from the Root Key (Key_V2X) (2i-25) and the encryption parameters ( Count, Bearer, Direction, Length (key stream block length)) as input parameters.

[385] FIG. 2J is a view illustrating a complete user plane data transmission and reception operation in the NR V2X system of the disclosure.

[386] With reference to FIG. 2J, in step 2j-10, the V2X NR supporting terminal 1 2j-01 receives parameters for the V2X NR service from the V2X server 2j-05 (Grant). At this time, the V2X server 2j-05 can transfer the parameters related to the V2X NR for terminals to the V2X control function 2j-04 in advance, authenticate the terminal, and transmit the parameters when the corresponding terminal requests the V2X NR service directly in the V2X control function 2j-04 . The parameters passed in the above step may include at least one of the following information.

[387] - Frequency information supporting LTE V2X and NR V2X

[388] - Mapping information between the layer-2 ID of the destination and the V2X service (for example, advanced sensor, advanced driving, column movement, etc. are mapped to PSID, ITS-AID, etc.)

[389] - Mapping between a V2X service and a V2X supported frequency/RAT (LTE or NR), i.e., a service supported by a particular frequency can be specified

[390] In step 2j-15, terminal 1 2j-01 anchors on the V2X frequency supporting the service of interest x. The V2X frequency may be a frequency supported by the HPLMN (Home PLMN). The frequency may be included in the parameter received in step 2j-10.

[391] In step 2j-20, the terminal 1 2j-01 receives system information for the V2X service from the base station 2j-03 anchored on the V2X frequency. The system information may include information capable of performing a V2X operation and representatively may include resource pool information. In addition, the resource pool information includes a transmission resource pool and a reception resource pool, and the 2j-01 terminal 1 that received the information in step 2j-25 can directly receive V2X data from another V2X terminal 2 2j-02 through the receive resource pool. .

[392] In step 2j-30, the terminal that has received the V2X MAC PDU from the receive resource pool decodes the header and subheader existing in the corresponding MAC PDU, distinguishes which service data the received MAC PDU is, and performs the first security processing operation (application receive packet security) for the SLRB to which the service is delivered.

[393] The first security processing operation is a data decoding operation by decoding the received MAC PDU and performing an appropriate decoding on a specific SLRB, which will be described in detail in FIG. 2KA and 2KB.

[394] When data is received via a direct connection and NR V2X data traffic to be transmitted from terminal 1 occurs at the same time (2j-35), the terminal prepares to transmit data via the transmission resource pool received in step 2j-20. Before valid data is transmitted, the terminal performs a second security processing operation (Transmission Packet Security Application). The second security processing operation is an operation of applying encryption to each SLRB to transmit a packet of data to be transmitted, and will be described in detail in FIG. 2KA and 2KB.

[395] When the encryption of the data to be transmitted is completed, the MAC SDU and header are configured and transmitted according to the MAC PDU format proposed in FIG. 2H (2j-45).

[396] FIG. 2KA and 2KB are views illustrating in detail the administration of a user plane radio bearer and an encryption operation of a terminal supporting NR V2X proposed in the embodiment of the disclosure.

[397] In steps 2k-05, the V2X NR capable terminal receives (or receives grant) parameters for the V2X NR service from the V2X server. At this time, the V2X server can send the V2X NR related parameters for the terminals to the V2X control function in advance, and when the terminal requests the V2X NR service authorization in the V2X control function, the terminal can be authenticated and the parameters can be delivered. The parameters transmitted in the above step have been described in detail in FIG. 2j.

[398] The terminal performs anchoring on a V2X frequency that supports the V2X service of interest x. The V2X frequency may be a frequency supported by the HPLMN. The terminal anchoring on the V2X frequency receives system information for the V2X service from the corresponding base station in step 2k-10.

[399] The system information may include information capable of performing a V2X operation, and representatively may include resource pool information. Also, the resource pool information may include a transmission resource pool and a reception resource pool.

[400] Accordingly, the terminal receiving the corresponding information can monitor the reception resource pool in step 2j-15 and immediately receive V2X data from another V2X terminal via the reception resource pool.

[401] When the terminal receives the NR V2X direct connection data packet, in step 2k-20, the terminal processes the received MAC PDU and performs a first security processing operation to transport the received MAC PDU to an upper layer. In other words, the terminal can determine the service type of the received packet by identifying the header and subheader of the received MAC PDU. The terminal can distinguish whether the corresponding packet is a new service or an existing service and operate accordingly.

[402] In step 2k-25, the terminal identifies whether there is a new LCID or a new SRC/DST pair in the subheader of the received MAC PDU.

[403] If both conditions are not satisfied, the terminal decodes the corresponding received packet in step 2k-30. That is, the terminal maps the received packet to an existing SLRB separate from the LCID and SRC/DST, and decodes the data by applying the decryption key applied to the SLRB. Specifically, when data decoding is performed in the above step, the root key obtained from the DST ID and additional information for decoding included in the header of the PDCP packet are used.

[404] If the terminal satisfies one of the two conditions in step 2k-25, then the terminal determines that the packet is indicated as a new service in step 2k-35 and sets a new SLRB. In other words, the terminal creates an RLC and PDCP constituting a new SLRB and initializes (or updates) the RLC/PDCP state variable.

[405] For example, if the received sub-PDU is a UMD PDU, the terminal transmits the sub-PDU to the RLC entity, and if the sub-PDU includes a UMD PDU segment, the RLC state variable is updated. At this time, the RLC state variable (RX_Next_Reassembly, RX_Next_Highest) is configured as the RLC SN included in the received first segment of the UMD PDU. This is because the MAC PDU received by a terminal from another terminal may not be the original transmission, but may be a transmission having an arbitrary RLC SN.

[406] In step 2k-40, it is determined whether the first DST MAC PDU received by the terminal is received, and if it matches the first DST ID, i.e., new service, the terminal matches the DST ID received in steps 2k-45. The encryption key is generated by the root key. The key is used for decryption and the SRC ID may also be applied to the key generation algorithm. In the above step, additional necessary information, such as key id information, upon receipt of the key used for actual decoding, may be included in the receive PDCP header.

[407] Upon receiving the already applied DST ID again, the terminal decodes the data packet by applying the known decoding key in steps 2k-55.

[408] At the same time, when performing the above operation, NR V2X data traffic is generated regardless of the terminal, and data can be transmitted via the transmission pool (2k-65).

[409] When V2X data transmission is started, the terminal performs the second security processing operation in steps 2k-70. In other words, the terminal performs a MAC PDU generation process for transmitting a data packet to be transmitted.

[410] In steps 2k-75, the terminal may determine whether a data packet to be transmitted can be delivered to a service that is already in use, such as an established SLRB. That is, the terminal can determine whether there is an SLRB (PDCP/RLC) corresponding to a data packet to be transmitted.

[411] If the service has already been used (ie, there is a preset SLRB), the terminal may generate a PDCP PDU for delivery to the SLRB in steps 2k-80. At this time, the terminal includes key id information etc. used to generate the PDCP PDU in the PDCP header. Thereafter, the encryption key applied to the SLRB is applied, the PDCP PDU is transmitted to the RLC after encryption, and the MAC PDU is generated and transmitted after the RLC header is added.

[412] If the data traffic to be transmitted by the terminal is for a new service, such as a packet to be transmitted via a new SLRB, the terminal generates a PDCP/RLC entity in steps 2k-85.

[413] In addition, the terminal may identify whether the first packet should be transmitted in steps 2k-90. If this is the first packet, the terminal generates a root key for the packet to be transmitted using the DST ID in steps 2k-95. In addition, the terminal generates a valid encryption key by applying the root key and the SRC ID to the key generation algorithm.

[414] Next, the terminal generates a PDCP PDU delivered to the SLRB in step 2k-100. At this time, the terminal includes the key id information used in the PDCP header. In the above, the terminal transmits the encrypted PDCP PDU to the RLC by applying the generated encryption key, adds the RLC header, and generates and transmits the MAC PDU.

[415] If the packet to be transmitted in steps 2k-90 is not the first one, the terminal generates a PDCP packet by applying the encryption key of the already applied SLRB, and generates and transmits a MAC PDU.

[416] FIG. 2L is a view illustrating a block configuration of a terminal according to an embodiment of the disclosure.

[417] As shown in FIG. 2L, a terminal according to an embodiment of the disclosure includes a transceiver 2l-05, a controller 2l-10, a multiplexing and demultiplexing unit 2l-15, and upper layer processors 2l-20 and 2l-25, and a control message processor 2l-30.

[418] The transceiver 2l-05 receives the data and the predetermined control signal via the forward channel of the serving cell, and transmits the data and the predetermined control signal via the reverse channel. When the plurality of serving cells are configured, the transceiver 2l-05 performs transmission/reception of data and transmission/reception of a control signal through the plurality of serving cells. The multiplexing and demultiplexing unit 2l-15 multiplexes the generated data from the upper-layer processing units 2l-20 and 2l-25 or the control message processing unit 2l-30, or demultiplexes the data received from the transmit/receive unit 2l-05 and transmits them to suitable upper level processing blocks (2l-20, 2l-25) or control message processing blocks (2l-30). The control message processor 2l-30 transmits and receives the control message from the base station and takes the necessary action. The action includes a function of processing control messages such as RRC and MAC CE messages, CBR measurement value messages, and receiving RRC messages for resource pool and terminal operation. Upper processors 2l-20 and 2l-25 are DRB devices and can be configured for each service. Upper layer processors 2l-20 and 2l-25 process data generated from user services such as File Transfer Protocol (FTP) or Voice over Internet Protocol (VoIP), and transfer the processed data to a multiplexing and demultiplexing unit (2l-15) or processing the data transmitted from the multiplexing and demultiplexing unit 2l-15, and delivering the processed data to the upper layer service application. The controller 2l-10 checks the scheduling commands received via the transceiver 2l-05, such as reverse grants to control the transceiver 2l-05 and the multiplexing and demultiplexing unit 2l-15, so that the reverse transmission is performed with the appropriate transmission resource at the appropriate time. Meanwhile, in the above, it has been described that the terminal is composed of a plurality of blocks and each block performs a different function, but this is only an exemplary embodiment, and the invention is not limited thereto. For example, the controller 2l-10 may itself perform the function that the demultiplexer 2l-15 performs.

[419] FIG. 2M is a view illustrating a block configuration of a base station according to an embodiment of the disclosure.

[420] The base station in FIG. 2M includes a transceiver 2m-05, a controller 2m-10, a multiplexing and demultiplexing unit 2m-20, a control message processor 2m-35, upper layer processors 2m-25 and 2m-30, and a scheduler 2m-15.

[421] The transceiver 2m-05 transmits data and a predetermined control signal via a forward carrier, and receives data and a predetermined control signal via a reverse carrier. When multiple carriers are configured, the transceiver 2m-05 performs data transmission/reception and control signal transmission/reception via the plurality of carriers. The multiplexing and demultiplexing unit 2m-20 multiplexes the data generated by the upper level processors 2m-25 and 2m-30 or the control message processor 2m-35, or demultiplexes the data received from the transceiver 2m-05 to transmit the data to the appropriate processors 2m-25 and 2m-30 upper level, 2m-35 control message processor or 2m-10 controller. The control message processor 2m-35 receives an instruction from the controller, generates a message to be transmitted to the terminal, and delivers the generated message to the lower layer. Upper layer processors 2m-25 and 2m-30 may be configured for each terminal service, process data generated from user services such as FTP or VoIP, and transfer data to the multiplexing and demultiplexing unit 2m-20, or process data transmitted from the multiplexing and demultiplexing unit 2m-20, and delivering the data to the higher layer service application. Scheduler 2m-15 allocates transmission resources to the terminal at an appropriate time based on the terminal's buffer status, channel status, and active time of the terminal, and processes a signal transmitted by the terminal to the transceiver or processes a signal to be transmitted to the terminal.

[422] In addition, the disclosure may be summarized as follows.

[423] 1. L2 header format for NR V2X

[424] A. PDU+m Header * (PDU+MAC SDU Subheader)

[425] B. PDU=R/R/R/R/V/SRC/DST Header

[426] C. Subtitle PDU=R/F/LCID/L

[427] (Reference) L2 header format for LTE V2X

[428] A. PDU Header+m * PDU+m Subheader * MAC SDU

[429] B. PDU=R/R/R/R/V/SRC/DST header

[430] C. Subtitle PDU=R/E/F/LCID/L

[431] 2. L2 Architecture and State/Timer Processing

[432] A. One SLRB=PDCP entity+RLC entity

[433] B. SLRB is identified by a pair of LCID and SRC/DST)

[434] C. The terminal sets a new SLRB when an unknown/new LCID or unknown SRC/DST pair is indicated in a PDU subheader or PDU header

[435] D. Timer/State Variable Handling (Initialization)

[436] i. T_Reassembly (RLC) and T_reordering (PDCP) set to zero

[437] ii. RLC state variables: V2X can receive data from other terminals in the middle

[438] 1. RX_Next_Reassembly is set to the SN of the segment received first.

[439] 2. RX_Next_Highest is set to the SN of the segment received first.

[440] iii. PDCP state variables: V2X can receive data from other terminals in the middle

[441] 1. RX_NEXT is set to the SN of the first received PDCP PDU

[442] 2. RX_DELIV is set to the SN of the first received PDCP PDU

[443] 3. Security key for the service

[444] A. Root key is identified/inferred by DST ID

[445] B. The encryption key is identified/inferred by the root key, SRC ID, and information in the PDCP header

[446] (Different passwords may apply for each device and message)

[447] In addition, the disclosure may be summarized as follows.

[448] 1. UE <- V2X Server: Provide Parameters

[449] - Display layer-2 ID of destination and V2X service, e.g. PSID, ITS-AID, advanced sensor, column movement...

[450] - Mapping of services to V2X/RAT frequencies (LTE and/or NR)

[451] 2. UE interested in V2X service x: Anchor on V2X HPLMN frequency mapped to service x

[452] 3. UE: Receiving V2X system information and determining a resource pool to receive and a resource pool to transmit

[453] 4. UE: Receive MAC PDU in receive pool

[454] 5. UE: L2/Security Handling

[455] - For sub-PDU

[456] -- If the SRC/DST MAC PDU pair is new; or

[457] -- Sub-PDU LCID is new

[458] create RLC and PDCP and direct sub-PDU for RLC entity

[459] If the sub-PDU contains a UMD PDU segment, update the RLC state variable accordingly

[460] Update PDCP state variable accordingly

[461] - If the DST MAC PDU is new/received for the first time

[462] -- Derive root key based on DST L2 ID

[463] -- Derive decryption key based on root key and SRC ID

[464] -- Decrypt received PDCP PDU

[465] 6. UE: V2X packet to be transmitted

[466] 7. UE: L2/Security Handling

[467] - If the corresponding PDCP/RLC does not exist

[468] -- Create PDCP object and RLC object

[469] - If the first packet is to be transmitted by the UE to the V2X destination/service

[470] -- Derive root key based on DST L2 ID

[471] -- Derive encryption key based on root key and SRC ID

[472] - Generate PDCP PDU and include key id in header

[473] - Encrypt Data Part of PDCP PDU

[474] - Send PDCP PDU to MAC PDU

[475] In the detailed embodiments of the disclosure described above, the element included in the disclosure is expressed in singular or plural in accordance with the detailed embodiments presented. However, the singular form or plural form is chosen appropriately for the present situation for convenience of description, and the disclosure is not limited to singular or plural elements. Therefore, any element expressed in the plural may also include a single element, or an element expressed in the singular may also include multiple elements.

[476] Although specific embodiments have been described in the detailed description of the disclosure, various modifications and changes can be made to them without deviating from the scope of the disclosure. Therefore, the scope of the disclosure should not be defined as being limited to the embodiments, but should be defined by the appended claims and their equivalents.

[477] In the drawings describing the methods of the disclosure, the order of description does not always correspond to the order in which the steps of each method are performed, and the order relationship between the steps may change, or the steps may be performed in parallel.

[478] Alternatively, in the drawings, which describe the methods according to the disclosure, some elements may be omitted, and only some elements may be included without deviating from the essential essence and scope of the disclosure.

[479] Additionally, in the methods of the disclosure, some or all of the contents of each embodiment may be combined without departing from the essential spirit and scope of the disclosure.

Claims (34)

1. A data transmission method performed by a first terminal in a communication system, the method comprising the steps of: a plurality of service data units (SDUs) of direct connection (MAC) media access control (sidelink) are obtained; generating a direct connection MAC protocol data unit (PDU) including a direct connection MAC PDU header and a plurality of direct connection sub-PDUs; and transmitting the Direct Connect MAC PDU to the second terminal, wherein each of said plurality of Direct Connect sub-PDUs includes a Direct Connect MAC SDU and a Direct Connect MAC subheader placed before the Direct Connect MAC SDU. 2. The method of claim 1, wherein the Direct Connect MAC PDU header further includes a version field indicating a version of the Direct Connect MAC PDU, wherein the version field has a bit size of 4 bits. 3. The method of claim 1, wherein the direct connection MAC subheader includes a logical channel ID (LCID) field that identifies the logical channel, a length field indicating the length of the direct connection MAC SDU, and a format field indicating the size of the length field. 4. The method of claim 3, wherein the format field value 0 indicates 8 length field bits and the format field value 1 indicates 16 length field bits. 5. A method for receiving data performed by a second terminal in a communication system, the method comprising the steps of: receiving from the first terminal a sidelink media access control (MAC) protocol data unit (PDU), and identifying the Direct Connect MAC PDU and a plurality of sub-PDUs from the Direct Connect MAC PDU, wherein each of said plurality of Direct Connect sub-PDUs includes a Direct Connect MAC Service Data Unit (SDU) and a Direct Connect MAC subheader placed before the Direct Connect MAC SDU. 6. The method of claim 5, wherein the Direct Connect MAC PDU header further includes a version field indicating a version of the Direct Connect MAC PDU, wherein the version field has a bit size of 4 bits. 7. The method of claim 5, wherein the direct connection MAC subheader includes a logical channel ID (LCID) field that identifies a logical channel, a length field indicating the length of the direct connection MAC SDU, and a format field indicating the size of the length field, wherein format field value 0 indicates 8 length field bits, and format field value 1 indicates 16 length field bits. 8. The method of claim 5, wherein the state variable for the Packet Data Convergence Protocol (PDCP) entity is set to the sequence number of the first received PDCP data PDU. 9. A first terminal for transmitting data in a communication system, the first terminal comprising: transceiver and a controller associated with the transceiver and configured to: receive a plurality of service data units (SDUs) of a media access control (MAC) of a direct connection (sidelink); generate a direct connection MAC protocol data unit (PDU) including a direct connection MAC PDU header and a plurality of direct connection sub-PDUs; and transmit the Direct Connect MAC PDU to the second terminal, wherein each of said plurality of Direct Connect sub-PDUs includes a Direct Connect MAC SDU and a Direct Connect MAC subheader placed before the Direct Connect MAC SDU. 10. The first terminal of claim 9, wherein the Direct Connect MAC PDU header further includes a version field indicating a version of the Direct Connect MAC PDU, wherein the version field has a bit size of 4 bits. 11. The first terminal of claim 9, wherein the direct connection MAC subheader includes a logical channel ID (LCID) field that identifies a logical channel, a length field indicating the length of the direct connection MAC SDU, and a format field indicating the size of the length field. 12. The first terminal of claim 11, wherein a format field value of 0 indicates 8 length field bits and a format field value of 1 indicates 16 length field bits. 13. A second terminal for receiving data in a communication system, the second terminal comprising: transceiver and a controller associated with the transceiver and configured to: receive from the first terminal a sidelink media access control (MAC) protocol data unit (PDU), and identify a direct-attach MAC PDU and a plurality of sub-PDUs from a direct-attach MAC PDU, wherein each of said plurality of Direct Connect sub-PDUs includes a Direct Connect MAC Service Data Unit (SDU) and a Direct Connect MAC subheader placed before the Direct Connect MAC SDU. 14. The second terminal of claim 13, wherein the header of the Direct Connect MAC PDU further includes a version field indicating a version of the Direct Connect MAC PDU, wherein the bit size of the version field is 4 bits. 15. The second terminal of claim 13, wherein the direct connection MAC subheader includes a logical channel ID (LCID) field that identifies a logical channel, a length field indicating the length of the direct connection MAC SDU, and a format field indicating the size of the length field, when In this case, the value of the format field 0 indicates 8 bits of the length field, and the value of 1 of the format field indicates 16 bits of the length field, and the state variable for the Packet Data Convergence Protocol (PDCP) entity is set to the sequence number of the first received PDCP data PDU. 16. The second terminal of claim 13, wherein the state variable for the Packet Data Convergence Protocol (PDCP) entity is set to the sequence number of the first received PDCP data PDU.

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