CN111587597A

CN111587597A - Method and apparatus for selecting carrier in wireless communication system

Info

Publication number: CN111587597A
Application number: CN201980008294.3A
Authority: CN
Inventors: 睦荣中; 姜贤贞
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2018-01-11
Filing date: 2019-01-11
Publication date: 2020-08-25
Anticipated expiration: 2039-01-11
Also published as: KR20190085819A; CN111587597B; EP3695667A1; EP3695667A4

Abstract

The present disclosure relates to 5G (fifth generation) or pre-5G communication systems to support higher data rates following 4G (fourth generation) communication systems such as LTE (long term evolution). The present disclosure provides an apparatus and method for efficiently selecting a transmission carrier in a wireless communication system. The present disclosure relates to a method of operating a terminal in a wireless communication system, the method comprising receiving configuration information from a base station and selecting a transmission carrier and a resource pool based on the configuration information.

Description

Method and apparatus for selecting carrier in wireless communication system

Technical Field

The present disclosure relates generally to wireless communication systems, and more particularly, to an apparatus and method for selecting carriers in a wireless communication system.

Background

The above information is provided as background information only to assist in understanding the present disclosure. No determination is made, nor is an assertion made, as to whether any of the above can be applied as prior art with respect to the present disclosure.

In order to meet the increasing demand for wireless data services after commercialization of 4G (fourth generation) communication systems, efforts are being made to develop improved 5G (fifth generation) communication systems or pre-5G communication systems. Therefore, the 5G communication system or the pre-5G communication system is referred to as a "super 4G network communication system" or a "Long Term Evolution (LTE) system".

In order to achieve high data rates, it has been considered to implement a 5G communication system in an ultra high frequency (mm wave) band (e.g., a 60GHz band). In order to mitigate path loss of radio waves and to increase propagation distance of radio waves in an ultra high frequency band, technologies such as beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antenna, analog beamforming, and massive antenna are being discussed in a 5G communication system.

In addition, in order to improve the network of the system, technologies such as evolved small cells, advanced small cells, cloud radio access networks (cloud ran), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, mobile networks, cooperative communication, coordinated multi-point (CoMP), reception interference cancellation, and the like are being developed in the 5G communication system.

In addition, in the 5G system, Advanced Coding Modulation (ACM) schemes such as hybrid frequency shift keying and quadrature amplitude modulation (FQAM) and Sliding Window Superposition Coding (SWSC), and advanced connection technologies such as filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA), Sparse Code Multiple Access (SCMA), and the like are being developed.

Vehicle-to-advertising (V2X) technology is being considered in the 5G system. When a terminal uses multiple carriers in a V2X system, it may be necessary to select a Transmission (TX) carrier that supports reliable data transmission. Therefore, a specific procedure for efficiently selecting a transmission carrier is being discussed in the V2X system.

Disclosure of Invention

Based on the above discussion, the present disclosure provides an apparatus and method for efficiently selecting a transmission carrier in a wireless communication system.

According to various embodiments of the present disclosure, a method for operating a terminal in a wireless communication system is provided. The method comprises the following steps: acquiring information about a first threshold and a second threshold of a Channel Busy Rate (CBR); measuring a first CBR of a first carrier configured by an upper layer and a plurality of second CBRs of a plurality of second carriers; and determining at least one transmission carrier from the first carrier and the plurality of second CBRs based on the first threshold, the second threshold, the first CBR, and the plurality of second CBRs.

According to various embodiments of the present disclosure, a terminal in a wireless communication system is provided. The terminal includes a transceiver; and a processor operatively coupled to the transceiver and configured to: the method includes acquiring information on a first threshold and a second threshold of a Channel Busy Rate (CBR), measuring a first CBR of a first carrier configured by an upper layer and a plurality of second CBRs of a plurality of second carriers, and determining at least one transmission carrier from the first carrier and the plurality of second CBRs based on the first threshold, the second threshold, the first CBR, and the plurality of second CBRs.

According to various embodiments of the present disclosure, a method for operating a base station in a wireless communication system is provided. The method comprises the following steps: transmitting information on a first threshold value and a second threshold value of a channel busy rate to a terminal; receiving a request for resource allocation using at least one transmission carrier determined based on a first threshold, a second threshold, a first CBR of a first carrier, and a plurality of second CBRs of a plurality of second carriers; and transmitting a resource allocation message for the available resources of the at least one transmission carrier.

Apparatuses and methods according to various embodiments of the present disclosure enable efficient selection of transmission carriers in a wireless communication system.

The effects obtainable in the present disclosure are not limited to the above description, and other effects not yet mentioned will be clearly understood from the following description by those skilled in the art.

Before proceeding with the following detailed description, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms "include" and "comprise," as well as derivatives thereof, mean inclusion without limitation; the term "or" is inclusive, meaning and/or; the phrases "associated with …" and "associated therewith," and derivatives thereof, may mean to include, be included within …, be interconnected with …, contain, be contained within …, be connected to or with …, be coupled to or with …, be in communication with …, cooperate with …, interleave, juxtapose, be proximate to, be joined to or with …, have the characteristics of …, and the like; and the term "controller" means any device, system or part thereof that controls at least one operation, such as a device that may be implemented in hardware, firmware or software, or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely.

Further, various functions described below may be implemented or supported by one or more computer programs, each of which is formed from computer-readable program code and embodied in a computer-readable medium. The terms "application" and "program" refer to one or more computer programs, software components, sets of instructions, procedures, functions, objects, classes, instances, related data, or a portion thereof adapted for implementation in suitable computer readable program code. The phrase "computer readable program code" includes any type of computer code, including source code, object code, and executable code. The phrase "computer readable medium" includes any type of medium capable of being accessed by a computer, such as Read Only Memory (ROM), Random Access Memory (RAM), a hard disk drive, a Compact Disc (CD), a Digital Video Disc (DVD), or any other type of memory. A "non-transitory" computer-readable medium excludes wired, wireless, optical, or other communication links that convey transitory electrical or other signals. Non-transitory computer-readable media include media in which data can be permanently stored and media in which data can be stored and subsequently rewritten, such as rewritable optical disks or erasable memory devices.

Definitions for certain words and phrases are provided throughout this patent document. Those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases.

Drawings

The above and other aspects, features and advantages of certain embodiments of the present disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:

fig. 1 illustrates a wireless communication system in accordance with various embodiments of the present disclosure;

fig. 2 illustrates a configuration of a base station in a wireless communication system according to various embodiments of the present disclosure;

fig. 3 illustrates a configuration of a terminal in a wireless communication system according to various embodiments of the present disclosure;

fig. 4 illustrates a flow diagram of the operation of a terminal according to various embodiments of the present disclosure;

fig. 5 illustrates a process in which one resource pool is set for a common or dedicated structure and then each resource pool is mapped with one component carrier, according to various embodiments of the present disclosure;

fig. 6 illustrates a process in which multiple resource pools are set for a common or dedicated structure and then each resource pool is mapped with one component carrier, according to various embodiments of the present disclosure;

fig. 7 illustrates a process in which multiple resource pools are set for a common or dedicated structure and then mapped with one component carrier, according to various embodiments of the present disclosure;

fig. 8 illustrates a process in which a terminal uses an event V1_ T1 for CBR when selecting a transmission carrier based on CBR, in accordance with various embodiments of the present disclosure;

fig. 9 illustrates a process in which a terminal requests resource allocation to a candidate resource pool selected by the process of fig. 8 (operation in mode 3), according to various embodiments of the present disclosure;

fig. 10 illustrates a process in which a terminal uses an event V1_ T2 for CBR when selecting a Transmission (TX) carrier based on CBR, in accordance with various embodiments of the present disclosure;

FIG. 11 illustrates a process in which a terminal uses event V2_ T1 for CBR, in accordance with various embodiments of the disclosure;

FIG. 12 illustrates a process in which a terminal uses event V2_ T2 for CBR, in accordance with various embodiments of the disclosure;

fig. 13 illustrates a process of selecting a resource pool based on mode 4 in a sub-layer internal to a terminal, in accordance with various embodiments of the present disclosure;

fig. 14 illustrates a process of selecting a resource pool based on mode 3 in a sub-layer internal to a terminal according to various embodiments of the disclosure;

fig. 15 illustrates a procedure in which a terminal uses an event V4_ T1 when selecting a transmission carrier in consideration of CBR and proximity packet priority (PPPP) in

respective scenarios

1 and 2 in fig. 5 and 6, according to various embodiments of the present disclosure;

fig. 16 shows a process in which a terminal uses an event V4_ T2 when selecting a transmission carrier in consideration of CBR and PPPP in scenario 3 of fig. 7, according to various embodiments of the present disclosure;

fig. 17 illustrates a process of selecting a resource pool in a sub-layer inside a terminal based on mode 4 according to the embodiments in fig. 15 and 16, according to various embodiments of the present disclosure;

fig. 18 illustrates a process of selecting a resource pool in a sub-layer inside a terminal based on mode 3 according to the embodiments in fig. 15 and 16, according to various embodiments of the present disclosure;

fig. 19 shows a process in which a terminal selects a transmission carrier in a case where data replication and transmission are applied using multiple carriers, according to various embodiments of the present disclosure;

fig. 20 illustrates a process in which a terminal initiates operation of a Transmit (TX) carrier timer, in accordance with various embodiments of the present disclosure;

fig. 21 illustrates a process in which a terminal operates a transmit carrier timer, in accordance with various embodiments of the present disclosure;

fig. 22 illustrates signal flows in which a terminal receives from a base station a Transmission (TX) carrier selection configuration to be applied to selection of a resource pool of a transmission carrier and a corresponding carrier, in accordance with various embodiments of the present disclosure;

fig. 23 illustrates signal flows in which a terminal receives configuration information for Transmission (TX) resource selection for data replication from a base station in accordance with various embodiments of the disclosure;

fig. 24A illustrates an example of initial operation of a V2X terminal for selecting a transmission carrier in accordance with various embodiments of the present disclosure;

fig. 24B illustrates an example of operation of a V2X terminal for reselecting a transport carrier according to various embodiments of the present disclosure; and

fig. 24C illustrates another example of operation in which the V2X terminal reselects a transport carrier, according to various embodiments of the present disclosure.

Detailed Description

Figures 1 through 24C, discussed below, and the various embodiments used to describe the principles of the present invention in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the invention. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged system or device.

The terminology used in the present disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. Singular expressions may include plural expressions unless they are completely different in context. Unless otherwise defined, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Terms such as those defined in general dictionaries may be interpreted as having a meaning that is equivalent to the contextual meaning in the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. In some cases, even terms defined in the present disclosure should not be construed to exclude embodiments of the present disclosure.

Hereinafter, the present disclosure relates to an apparatus and method for selecting a transmission carrier in a wireless communication system. More specifically, the present disclosure describes a technique for selecting a transmission carrier in a multi-carrier scenario in a wireless communication system.

Terms related to a communication scheme, terms related to a signal, terms related to information, terms related to a network entity, terms related to an element of a device, and the like, which are used hereinafter are explanatory words for convenience of explanation. Accordingly, the present disclosure is not limited to the terms described later, and other terms having equivalent technical meanings may be used.

Furthermore, the present disclosure describes various embodiments using terms used in some communication standards, such as the third generation partnership project (3 GPP), but this is merely an illustrative example. Various embodiments of the present disclosure may be readily modified and applied to other communication systems.

Fig. 1 illustrates a wireless communication system in accordance with various embodiments of the present disclosure. Fig. 1 shows

base stations

101 and 102 and

terminals

121, 123, 125, 127 and 129 as part of a node using a radio channel in a wireless communication system.

Base stations

101 and 102 are the network infrastructure that provides wireless access to

terminals

120, 123, 125, 127 and 129.

Base stations

101 and 102 have a coverage area (coverage) defined as a certain geographical area based on the distance over which signals may be transmitted. The

base station

101 or 102 may be referred to as an "Access Point (AP)", "enodeb (enb)", "fifth generation (5G) node", "wireless point", "transmission/reception point (TRP)" or other terms having technical equivalents, and a base station.

Each of the

terminals

121, 123, 125, 127, and 129 is a device used by a user and communicates with the

base stations

101 and 102 via a wireless channel. In some cases, at least one of

terminals

121, 123, 125, 127, and 129 may operate without user involvement. That is, at least one of the

terminals

121, 123, 125, 127, and 129 may be a device for performing Machine Type Communication (MTC) and may not be carried by a user. Each of the

terminals

121, 123, 125, 127, and 129 may be referred to as a "User Equipment (UE)", a "mobile station", "subscriber station", "remote terminal", "wireless terminal", "user equipment", or other terms having technical equivalents, and a terminal.

Fig. 1 illustrates various examples of communications that may be performed. For example, communication between base station 101 and terminal 121 may be performed. As another example, a direct link between two terminals may be used for communication. That is, communication may be performed using a direct link between two

terminals

121 and 123 within the service range of the base station 101, communication may be performed using a direct link between the terminal 121 within the service range of the base station 101 and the terminal 125 outside the service range of the base station 101, and communication may be performed using a direct link between two

terminals

125 and 127 outside the service range of the base station 101. Alternatively, communication may be performed using a direct link between

terminals

121 and 129,

terminals

121 and 129 being within the service area of

different base stations

101 and 102, respectively.

For communication using a direct link, the

terminals

121, 123, 125, 127, and 129 may use an Intelligent Transportation System (ITS) band (e.g., 5.9GHz) instead of using frequency resources of the

base stations

101 and 102.

Terminals

121 and 123 within the service range of base station 101 may set parameters for communication of base station 101 and terminal 129 within the service range of base station 102 may set parameters for communication of base station 102.

Terminals

125 and 127 that are out of service range of base station 101 may operate according to a predefined configuration.

In the present disclosure, the

terminals

121, 123, 125, and 127 may operate as a transmitting terminal or a receiving terminal when performing mutual communication. The roles of the transmitting terminal and the receiving terminal are not fixed but variable. For example, terminal 121 may operate as a transmitting terminal at a particular time and may operate as a receiving terminal at another time. Alternatively, the terminal 121 may operate as a transmitting terminal in a certain frequency band and may operate as a receiving terminal in another frequency band.

Fig. 2 illustrates a configuration of a base station in a wireless communication system according to various embodiments of the present disclosure. The configuration shown in fig. 2 can be regarded as the configuration of the base station 101. Hereinafter, the terms "unit", "device", and the like denote a unit for processing at least one function or operation, and may be implemented by hardware, software, or a combination thereof.

Referring to fig. 2, the base station includes a wireless communication unit 210, a backhaul communication unit 220, a storage unit 230, and a controller 240.

The wireless communication unit 210 may perform a function of transmitting and receiving a signal via a wireless channel. For example, the wireless communication unit 210 may perform a function of converting between a baseband signal and a bit stream according to a physical layer standard of the system. For example, in case of data transmission, the wireless communication unit 210 may generate complex symbols by encoding and modulating a transmission bit stream. In the case of data reception, the wireless communication unit 210 can restore the received bit stream by demodulating and decoding the baseband signal.

Further, the wireless communication unit 210 may up-convert a baseband signal into a Radio Frequency (RF) band signal so as to transmit the signal via an antenna, and may down-convert an RF band signal received via the antenna into a baseband signal. To this end, the wireless communication unit 210 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), and the like. Further, the wireless communication unit 210 may include a plurality of transmission/reception paths. Further, the wireless communication unit 210 may comprise at least one antenna array comprising a plurality of antenna elements.

In terms of hardware, the wireless communication unit 210 may include a digital unit and an analog unit, and the analog unit may include a plurality of sub-units depending on an operating power, an operating frequency, and the like. The digital unit may be implemented as at least one processor (e.g., a Digital Signal Processor (DSP)).

The wireless communication unit 210 transmits and receives signals as described above. Accordingly, all or some of the wireless communication units 210 may be referred to as "transmitters," receivers, "or" transceivers. In the following description, transmission and reception performed via a wireless channel will be used as meaning including processing performed by the wireless communication unit 210 as described above.

The backhaul communication unit 220 provides an interface for communicating with other nodes in the network. That is, the backhaul communication unit 220 converts a bit stream transmitted from a base station to another node (such as another access node, another base station, an upper node, or a core network) into a physical signal and converts a physical signal received from another node into a bit stream.

The storage unit 230 may store data for the operation of the base station, such as basic programs, application programs, and configuration information. The storage unit 230 may be configured as a volatile memory, a non-volatile memory, or a combination thereof. In addition, the storage unit 230 provides stored data at the request of the controller 240.

The controller 240 controls the overall operation of the base station. For example, the controller 240 transmits and receives signals through the wireless communication unit 210 or the backhaul communication unit 220. The controller 240 writes data to the memory unit 230 or reads data from the memory unit 230. The controller 240 may perform functions of a protocol stack for a communication standard. According to an example of another implementation, a protocol stack may be included in the wireless communication unit 210. To this end, the controller 240 may include at least one processor.

Fig. 3 illustrates a configuration of a terminal in a wireless communication system according to various embodiments of the present disclosure. The configuration shown in fig. 3 can be regarded as the configuration of one of the

terminals

121, 123, 125, 127, and 129. Hereinafter, the terms "unit", "device", and the like denote a unit for processing at least one function or operation, and may be implemented by hardware, software, or a combination thereof.

Referring to fig. 3, the terminal includes a communication unit 310, a storage unit 320, and a controller 330.

The communication unit 310 performs a function of transmitting and receiving a signal via a wireless channel. For example, the communication unit 310 may perform a function of converting between a baseband signal and a bitstream according to a physical layer standard of the system. For example, in case of data transmission, the communication unit 310 may generate complex symbols by encoding and modulating a transmission bit stream. In case of data reception, the communication unit 310 may restore a received bit stream by demodulating and decoding a baseband signal. Further, the communication unit 310 may up-convert a baseband signal into an RF band signal to transmit the signal via the antenna, and may down-convert an RF band signal received via the antenna into a baseband signal. To this end, the communication unit 310 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, and the like.

Further, the communication unit 310 may include a plurality of transmission/reception paths. Furthermore, the communication unit 310 may comprise at least one antenna array comprising a plurality of antenna elements. In terms of hardware, the communication unit 310 may include digital circuits and analog circuits (e.g., Radio Frequency Integrated Circuit (RFIC)). Here, the digital circuit and the analog circuit may be implemented as a single package. The communication unit 310 may include a plurality of RF chains. Further, the communication unit 310 may perform beamforming.

Further, the communication unit 310 may include a plurality of communication modules to support a plurality of different radio access technologies. For example, the different Wireless access technologies may include Bluetooth Low Energy (BLE), Wireless Fidelity (Wi-Fi)^TM) Wireless gigabytes (WiFi gigabytes), cellular networks { e.g., Long Term Evolution (LTE) }. In addition, the different frequency bands may include a super-high frequency (SHF) (e.g., 3.5GHz or 5GHz) frequency band and a millimeter wave (e.g., 60GHz) frequency band.

The communication unit 310 transmits and receives signals as described above. Accordingly, all or some of the communication units 310 may be referred to as "transmitters," receivers, "or" transceivers. In the following description, transmission and reception performed via a wireless channel will be used as meaning including processing performed by the communication unit 310 as described above.

The storage unit 320 may store data for terminal operations, such as basic programs, application programs, and configuration information. The storage unit 320 may be configured as a volatile memory, a non-volatile memory, or a combination thereof. In addition, the storage unit 320 provides stored data at the request of the controller 330.

The controller 330 controls the overall operation of the terminal. For example, the controller 330 transmits and receives signals through the communication unit 310. The controller 330 writes data to the memory unit 320 or reads data from the memory unit 320. The controller 330 may perform the functions of a protocol stack for a communication standard. To this end, the controller 330 may include at least one processor or microprocessor, or may be part of a processor. Further, portions of the communication unit 310 and the controller 330 may be referred to as a "Communication Processor (CP)".

Fig. 4 illustrates a flow diagram of the operation of a terminal according to various embodiments of the present disclosure.

Referring to fig. 4, a terminal receives configuration information from a base station in step 401. In another embodiment, if the terminal does not receive the configuration information from the base station in step 401, the pre-configuration information preset in the terminal may be used. The configuration information received by the terminal from the base station or the pre-configuration information preset in the terminal may include at least one of a frequency ID, a resource pool ID, resource pool information, transmission carrier and resource pool selection event type information, threshold information of a Channel Busy Ratio (CBR), and a transmission carrier timer value.

In step 402, the terminal selects a transmission carrier and a resource pool based on the configuration information. The terminal according to various embodiments of the present disclosure may compare a channel busy rate of a resource pool of a service frequency with channel busy rates of a plurality of candidate resource pools, and may select a transmission resource pool from the plurality of candidate resource pools satisfying the above condition if a result of the comparison satisfies a condition of an event corresponding to a transmission carrier and resource pool selection event type information. Further, if the result of the comparison does not satisfy the condition, the terminal may select a resource pool of the service frequency.

In addition, the terminal according to various embodiments of the present disclosure may compare channel busy rates of a resource pool group of service frequencies with channel busy rates of a plurality of candidate resource pool groups, and if the result of the comparison satisfies conditions of an event corresponding to a transmission carrier and resource pool selection event type information, may select a transmission resource pool group from the candidate resource pool groups satisfying the above conditions, and may select a transmission resource pool satisfying the conditions from the transmission resource pool group. Further, if the result of the comparison does not satisfy the condition, the terminal may select a resource pool of the service frequency.

In addition, the terminal according to various embodiments of the present disclosure may compare a channel busy rate of a resource pool of a service frequency with channel busy rates of a plurality of predetermined candidate resource pools, and if a result of the comparison satisfies a certain condition, may select a transmission carrier from among the candidate resource pools satisfying the certain condition among the plurality of predetermined candidate resource pools. Further, if the result of the comparison does not satisfy a specific condition, the terminal may select a transmission carrier from a resource pool of the service frequency.

According to various embodiments of the present disclosure, after step 402, the terminal may sense available resources using the selected candidate resource pool (mode 4), or may request resource allocation from the selected candidate resource pool (mode 3).

Fig. 5 illustrates a process in which one resource pool is set for a common or dedicated structure and then each resource pool is mapped with one component carrier according to various embodiments of the present disclosure.

The terminal may set resources available in a Radio Resource Control (RRC) by identifying an RRC state, may then determine resources to be actually used in a Medium Access Control (MAC), or may then request resources to be actually used in the MAC.

For example, if the terminal is in the RRC connected state, the terminal may use, for the dedicated resource pool, one of (1) scheduling V2x-scheduling pool in SL-V2X-ConfigDedicated received as RRC configuration information, or (2) UE-selected CommmTxPhooIlNormalised in SL-V2X-ConfigDedicated received as RRC configuration information.

For example, if the terminal is in the RRC idle state, the terminal may select one of (1) V2 x-CommtxPhool NormalCommon received from system information or (2) pre-configured SL-V2X-preconfigurCommPool for the dedicated resource pool.

Scenario 1 according to the embodiment in fig. 5 is as follows.

The system operates multiple common resource pools (e.g., resource pool 504 or resource pool 506) or multiple dedicated resource pools (e.g., resource pool 502), where one resource pool is set for each of the common and dedicated structures and each resource pool is mapped with one component carrier. Further, the system may operate at least one exception (exception) resource pool (e.g., resource pool 508).

In the case of operating a plurality of common resource pools, a case where each component carrier is mapped with one resource pool may be considered.

In a multiple common resource pool architecture, the system information block may include resource information such as v2x-comm (x port normalcommon) 1, v2x-comm (x port normalcommon) 2. An example, denoted as RRC asn.1, is shown in table 1 below.

[ Table 1]

Referring to table 1, the first common resource and the second common resource may be resources of different locations. With reference to the structure of SL-V2X-ConfigCommon-r14, V2x-comm tpool normalcommon1 denotes a first common resource, and V2x-comm tpool normalcon 2 denotes a second common resource. A piece of resource pool information is included in the common resource structure. One resource pool is connected to one component carrier. In table 1, it is assumed that the carrier index of each resource pool is different.

The terminal may use a plurality of dedicated resources or a plurality of common resources, or may use an abnormal resource. The dedicated resource is a resource that the base station can allocate to a specific terminal in the V2X sidelink, and when allocated by the base station, the dedicated resource can be used by the specific terminal. The common resource is a resource allocated by the base station to the terminal in the V2X sidelink, and may be used by the terminal based on sensing. The abnormal resource is a resource that the base station allocates to the terminal in the V2X sidelink, and may be used when a dedicated resource or a common resource is not available (for example, during handover, during transition from an idle state to an active state, or when a dedicated resource or a common resource is not specified).

In the case of operating a plurality of dedicated resource pools, a case where each component carrier is mapped with one resource pool may be considered. For example, in a structure of a plurality of dedicated resource pools, the first dedicated resource and the second dedicated resource may be resources at different locations.

An example, denoted as RRC asn.1, is shown in table 2 below.

[ Table 2]

Referring to Table 2, SL-V2X-ConfigDedcated 1 represents a first dedicated resource, and SL-V2X-ConfigDedcated 2 represents a second dedicated resource. These are omitted in fig. 5.

Fig. 6 illustrates a process in which multiple resource pools are set for a common or dedicated structure and then each resource pool is mapped with one component carrier, according to various embodiments of the present disclosure.

The operation of identifying the terminal state is performed in the same manner as the embodiment of fig. 5.

The terminal can set resources available to the terminal in RRC by identifying a terminal state (i.e., RRC state), and then can determine resources to be actually used in MAC, or can then request resources to be actually used in MAC.

Scenario 2 according to the embodiment in fig. 6 is as follows.

Multiple resource pools (e.g., resource pool 602-1, resource pool 602-2, resource pool 604-1, and resource pool 604-2) may be provided for each of the common and dedicated structures, and each resource pool may be mapped with a single component carrier. In the case of the embodiment denoted RRC asn.1, it is assumed that the carrier index is different for each resource pool.

The terminal may include multiple dedicated resources or multiple common resources or may include anomalous resources (e.g., resource pool 606-1 and resource pool 606-2). The dedicated resource is a resource that the base station can allocate to a specific terminal in the V2X sidelink, and when allocated by the base station, the dedicated resource can be used by the specific terminal. The common resource is a resource allocated by the base station to the terminal in the V2X sidelink, and may be used by the terminal based on sensing. The abnormal resource is a resource that the base station allocates to the terminal in the V2X sidelink, and may be used when a dedicated resource or a common resource is not available (for example, during handover, during transition from an idle state to an active state, or when a dedicated resource or a common resource is not specified).

Each resource pool may inform the location of a different resource. For example, the first dedicated resource and the second dedicated resource have different locations. Further, for example, the third common resource and the fourth common resource have different locations.

Example 1 of dedicated resources denoted RRC asn.1 is shown in table 3 below.

[ Table 3]

Referring to table 3, v2x-scheduling pool may be represented as a structure of SL-comm resource pool v2X, v2x-scheduling pool1 represents a first dedicated resource, and v2x-scheduling pool2 represents a second dedicated resource.

Example 2 of dedicated resources denoted RRC asn.1 is shown in table 4 below.

[ Table 4]

Referring to table 4, v2x-scheduling pool may be represented as a list by SL-comm resource zooollistv 2X, and the first dedicated resource and the second dedicated resource may be included in SL-comm resource zooollistv 2X.

Table 5 below shows an example of common resources denoted RRC asn.1.

[ Table 5]

Referring to table 5, for example, the third common resource and the fourth common resource may be resources of different locations. v2 xcommptonmolconlnormalcormonmay be represented as a list by SL-commtxpoolistv 2X, and the third and fourth common resources may be included in SL-commtxpoolcitv 2X.

Fig. 7 illustrates a process in which multiple resource pools are set for a common or dedicated structure and then mapped with one component carrier, according to various embodiments of the present disclosure.

The operation of identifying the terminal state is performed in the same manner as the embodiment in fig. 5.

The terminal can set resources available to the terminal in RRC by identifying an RRC state, and then can determine resources to be actually used in MAC, or can then request resources to be actually used in MAC.

Scenario 3 according to the embodiment in fig. 7 is as follows.

In the case where a plurality of resource pools are provided for each of the dedicated and common structures and the plurality of resource pools are mapped with a single component carrier, the resource pool mapped with the single component carrier may be defined as a resource pool group.

A terminal may include multiple dedicated resources (e.g., resource pool 702-1 and resource pool 702-2) or multiple common resources (e.g., resource pool 704-1, resource pool 704-2, resource pool 706-1, and resource pool 706-2), or may include anomalous resources (e.g., resource pool 708-1 and resource pool 708-2). The dedicated resource is a resource that the base station can allocate to a specific terminal in the V2X sidelink, and when allocated by the base station, the dedicated resource can be used by the specific terminal. The common resource is a resource allocated by the base station to the terminal in the V2X sidelink, and may be used by the terminal based on sensing. The abnormal resource is a resource that the base station allocates to the terminal in the V2X sidelink, and may be used when a dedicated resource or a common resource is not available (for example, during handover, during transition from an idle state to an active state, or when a dedicated resource or a common resource is not specified).

Each resource pool may inform the location of a different resource.

Example 1 of RRC asn.1 with respect to dedicated resources for each frequency is shown in table 6 below. For example, the first dedicated resource and the second dedicated resource may be resources of different locations.

[ Table 6]

Referring to Table 6, V2x-scheduling Pool1 of SL-V2X-ConfigDedicated1 represents a first dedicated resource, V2x-scheduling Pool2 of SL-V2X-ConfigDedicated1 represents a second dedicated resource, V2x-scheduling Pool3 of SL-V2X-ConfigDedicated2 represents a third dedicated resource, and V2x-scheduling Pool4 of SL-V2X-ConfigDedicated2 represents a fourth dedicated resource.

Example 2 of RRC asn.1 with respect to dedicated resources for each frequency is shown in table 7 below.

[ Table 7]

Referring to table 7, v2x-scheduling pool may be represented as a list by SL-comm resource zooollistv 2X-r15, and the first and second dedicated resources may be included in SL-comm resource zooollistv 2X-r 15.

Example 1 of RRC asn.1 of common resources is shown in table 8 below. For example, the first dedicated resource, the second dedicated resource, the third dedicated resource, and the fourth dedicated resource may be resources of different locations.

[ Table 8]

Referring to the structure of SL-V2X-ConfigCommon-r14 in Table 8 above, V2 x-CommTxPoolNormaliCommon 1 represents the first and second common resource pools by SL-CommTxPoolListV2X-r14, and V2 x-CommTxPoolNormaliCommon 2 represents the third and fourth common resource pools by SL-CommTxPoolListV2X-r 14.

Example 2 of RRC asn.1 of common resources is shown in table 9 below.

[ Table 9]

Referring to the structure of SL-V2X-ConfigCommonList-r15 in Table 9 above, the first and second common resource pools may be represented by a first SL-V2X-ConfigCommon-r15 (included in SL-CommTxPoolList V2X-r 14) of SL-V2X-ConfigCommonList-r15, and the third and fourth common resource pools may be represented by a second SL-V2X-ConfigCommonList-r15 (included in SL-CommTxPoolList V2X-r 14) of SL-V2X-ConfigCommonList-r 15.

Embodiments of operations of a terminal according to various embodiments of the present disclosure when the terminal selects a Transmission (TX) carrier based on a Channel Busy Rate (CBR) will be described with reference to fig. 8 through 12.

Fig. 8 illustrates a process of using an event V1_ T1 for CBR when a terminal selects a transmission carrier based on CBR, according to various embodiments of the present disclosure. In the following description, the candidate resource pool refers to a resource pool having a frequency different from a service frequency. The service frequency refers to a camped (cached) frequency or a frequency of a previously used resource pool.

Referring to fig. 8, in step 801, the terminal compares the CBR of the currently used resource pool with the CBR result of the candidate resource pool. The CBR measurement of the resource pool (coolidentity-r 14) can be reflected as CBR-PSSCH-r14 and CBR-PSCCH-r14 in RRC. Referring to Table 10 below, the values of cbr-PSSCH-r14 and cbr-PSCCH-r14 are integers from 0 to 100.

[ Table 10]

In step 803, the terminal identifies whether the event V1_ T1 condition is satisfied. The event V1_ T1 may be defined as one of (1) a CBR difference between the serving frequency resource and the candidate resource pool, (2) a CBR value of the candidate resource pool, (3) a CBR difference between the serving frequency resource and the candidate resource pool and a CBR value of the candidate resource pool, and (4) an event having a lowest CBR value of the serving frequency resource.

If the CBR result for the service frequency resource is higher than the CBR result for the candidate resource pool by CBR _ Threshold _ a or more, the candidate resource pool is more likely to be included in the transmission resource candidates. The following is a condition under which the candidate resource pool is included in the transmission resource candidates.

CBR_servingPool-CBR_candidatedPool>CBR_Threshold_A

If the CBR result for the candidate resource pool is less than CBR Threshold B, the candidate resource pool is more likely to be included in the transmission resource candidates. The following is a condition under which the candidate resource pool is included in the transmission resource candidates.

CBR_candidatedPool<CBR_Threshold_B

If the CBR result of the service frequency resource is higher than the CBR result of the candidate resource pool by CBR _ Threshold _ a or more, and if the CBR result of the candidate resource pool is lower than CBR _ Threshold _ B, the candidate resource pool is more likely to be included in the transmission resource. The following is a condition under which the candidate resource pool is included in the transmission resource candidates.

CBR _ servingPool-CBR _ candeddPool > CBR _ Threshold _ A and

CBR_candidatedPool<CBR_Threshold_B

if the serving frequency resource has the lowest CBR value, the serving frequency resource is selected. Otherwise, a resource is selected from the candidate resource pool.

A Time-to-trigger (TTT) may be operated for event V1_ T1. If the event V1_ T1 is satisfied during the TTT, the candidate resource pool is included in the transmission resource candidates. Otherwise, it is not included in the transmission resource candidates. In mode 3, TTT may be used to prevent frequent frequency switching of the terminal and frequent resource allocation request/resource allocation signaling between the terminal and the base station.

Table 11 below shows example 1 of RRC asn.1 for event V1_ T1. For example, it may be set in a dedicated RRC message or system information.

[ Table 11]

In step 805, the terminal selects a resource pool of candidate frequencies and corresponding frequencies from among the candidate resource pools satisfying the event V1_ T1 condition in step 803 using one of the following methods. According to an embodiment, the terminal may select a resource pool having the lowest CBR from among the candidate resource pools. According to another embodiment, the terminal may randomly select a resource pool from the candidate resource pools.

In step 807, the terminal senses resources available for V2X communication using the selected resource pool of the selected candidate frequency (operation in mode 4), or the terminal transmits a request for resource allocation of the selected resource pool of the selected candidate frequency to the base station (operation in mode 3).

In mode 3, an operation in which the terminal transmits a request for resource allocation of the selected resource pool of the selected candidate frequency to the base station will be described later with reference to fig. 9.

In mode 3 and mode 4, in order to instruct the terminal to keep using a candidate frequency or a candidate resource pool for a predetermined period of time, a Transmission (TX) carrier timer may be set. The transmission carrier timer may minimize the probability of resource collision in the corresponding carrier due to frequent changes of the transmission carriers. When the terminal selects to use the candidate frequency and the resource pool of the candidate frequency instead of the service frequency and the resource pool of the service frequency, the transmission carrier timer may be specified so that the terminal may use the selected candidate frequency for a predetermined period of time, and the predetermined period of time may be set to the value of the transmission carrier timer. In another embodiment, the transmission carrier timer may be set to specify that the terminal uses the selected candidate frequency and the selected resource pool of the corresponding frequency within a predetermined time period.

In step 809, if the event V1_ T1 condition is not satisfied in step 803, the terminal may perform the use of the resource based on the mode 3 or the mode 4 with respect to the resource pool of the service frequency while maintaining the selection of the resource pool of the service frequency.

Fig. 9 illustrates a process in which a terminal requests resource allocation to a candidate resource pool selected by the process of fig. 8 (operation in mode 3), according to various embodiments of the present disclosure.

Referring to fig. 9, in step 901, the terminal 121 determines to request resource allocation to the candidate resource pool selected in step 807 of fig. 8 (mode 3 operation).

In step 903, the terminal 121 requests the base station 101 for mode 3 resources in the resource pool selected in step 901.

Example 1: using RRC SildelinkUEinformation messages

(1) The terminal transmits a SidelinkUEInformation message including at least one of a frequency ID, a resource pool ID, and a destinationinfisti to the base station 101, thereby requesting resources in the candidate resource pool.

(2) An example of asn.1 of the RRC message used when the terminal 121 makes a request to the base station 101 for resource allocation of the selected resource pool of candidate frequencies is shown in table 12 below.

[ Table 12]

Example 2: using MAC Control Element (CE)

(1) The terminal transmits a side-link Buffer Status Report (BSR) including at least one of a destination ID, a logical channel group ID, a buffer size, a frequency ID, and a resource pool ID to the base station 101, thereby requesting resource allocation from the candidate resource pool.

In step 905, the base station 101 can allocate resources to the terminal 121 using information of the RRC message or information of the MAC CE transmitted from the terminal 121.

Example (c): using Downlink Control Information (DCI) 5A

(1) The base station provides a carrier indicator and resource location information to allocate resources to the candidate resource pool.

Fig. 10 illustrates a process of using an event V1_ T2 for CBR when a terminal selects a Transmission (TX) carrier based on CBR, according to various embodiments of the present disclosure. In the following description, the candidate resource pool refers to a resource pool having a frequency different from a service frequency. The service frequency may be a parking frequency or may correspond to a frequency of a previously used resource pool.

Referring to fig. 10, in step 1001, the terminal compares the CBR of the currently used resource pool with the CBR result of the candidate resource pool. The CBR measurement of the resource pool (coolidentity-r 14) can be reflected as CBR-PSSCH-r14 and CBR-PSCCH-r14 in RRC. Referring to Table 13 below, the values of cbr-PSSCH-r14 and cbr-PSCCH-r14 are integers from 0 to 100.

[ Table 13]

In step 1003, the terminal identifies whether the event V1_ T2 condition is satisfied. The event V1_ T2 may be defined as one of (1) a case where the CBR value of the service frequency is higher than CBR _ Threshold _ a (e.g., when the probability of occurrence of a resource conflict or resource shortage is high) and (2) a case where the CBR value of the candidate resource is lower than CBR _ Threshold _ B (e.g., the probability of occurrence of a resource conflict or resource shortage is low).

The following are conditions under which the candidate resource pool is included in the transmission resource candidates.

CBR _ servingPool > CBR _ Threshold _ A and

CBR_neighboring<CBR_Threshold_B

the terminal may selectively operate the TTT for the event V1_ T2.

Table 14 below shows an example of RRC asn.1 for event V1_ T2. May be set in a dedicated RRC message or system information.

[ Table 14]

In step 1005, the terminal selects a resource pool of candidate frequencies and corresponding frequencies from the candidate resource pools satisfying the event V1_ T2 condition in step 1003 using one of the following methods. According to an embodiment, the terminal may select a resource pool having the lowest CBR from among the candidate resource pools. According to another embodiment, the terminal may randomly select a resource pool from the candidate resource pools.

In step 1007, the terminal senses available resources using the determined resource pool (operation in mode 4), or the terminal transmits a request for resource allocation of the selected candidate resource pool of the selected candidate frequency to the base station (operation in mode 3).

In mode 3, an operation in which the terminal makes a request to the base station for resource allocation of the selected resource pool of the selected candidate frequency is performed in the same manner as the embodiment in fig. 9.

In step 1009, if the event V1_ T2 condition is not satisfied in step 1003, the terminal may use the resource pool of the service frequency.

Fig. 11 illustrates a process for a terminal to use an event V2_ T1 in scenario 3 of fig. 7, according to various embodiments of the disclosure. In the following description, the candidate resource pool refers to a resource pool having a frequency different from a service frequency. The service frequency may be a parking frequency or may correspond to a frequency of a previously used resource pool. Further, in scenario 3 of fig. 7, when a plurality of resource pools are allocated to one component carrier, a resource pool group refers to a group of resources constituting one Component Carrier (CC).

Referring to fig. 11, in step 1101, the terminal compares the CBR of the currently used resource pool group with the CBR result of the candidate resource pool group. The CBR measurement of the resource pool (coolidentity-r 14) can be reflected as CBR-PSSCH-r14 and CBR-PSCCH-r14 in RRC. Referring to Table 15 below, the values of cbr-PSSCH-r14 and cbr-PSCCH-r14 are integers from 0 to 100.

[ Table 15]

In step 1103, the terminal identifies whether each resource pool satisfies the event V2_ T1 condition. Event V2_ T1 may be defined as one of (1) the CBR difference between the service frequency resource and the candidate resource pool, (2) the CBR value of the candidate resource pool, (3) the CBR difference between the service frequency resource and the candidate resource pool and the CBR value of the candidate resource pool, and (4) the event with the lowest CBR value of the service frequency resource.

In an embodiment, the CBR value for a candidate pool of resource pools may be an average CBR value for the resource pools belonging to the respective group. In another embodiment, the CBR value of the candidate resource pool group may be the lowest CBR value among the resource pools belonging to the respective group.

In the case where the CBR result of the service frequency resource is higher than the CBR result of the candidate resource pool group by CBR _ Threshold _ or more, for example, if the CBR value of the candidate resource pool group is the average CBR value or the lowest CBR value, the candidate resource pool is more likely to be included in the transmission resource candidates. The following is a condition under which the candidate resource pool is included in the transmission resource candidates.

CBR_servingPool-CBR_candidatedPool>CBR_Threshold_A

In case the CBR result of the candidate resource pool group is less than CBR _ Threshold _ B, the candidate resource pool is more likely to be included in the transmission resource candidates, e.g. if the CBR value of the candidate resource pool group is the average CBR value or the lowest CBR value. The following is a condition under which the candidate resource pool is included in the transmission resource candidates.

CBR_candidatedPool<CBR_Threshold_B

If the CBR result of the service frequency resource is higher than the CBR result of the candidate resource pool by CBR _ Threshold _ a or more, and if the CBR result of the candidate resource pool is lower than CBR _ Threshold _ B, the candidate resource pool is more likely to be included in the transmission resource candidates. The following is a condition under which the candidate resource pool is included in the transmission resource candidates.

CBR _ servingPool-CBR _ candeddPool > CBR _ Threshold _ A and

CBR_candidatedPool<CBR_Threshold_B

A Time To Trigger (TTT) may be operated for event V2_ T1. If the event V2_ T1 is satisfied during the TTT, a pool of candidate resources is included in the transmission resource candidates. Otherwise, it is not included in the transmission resource candidates. In mode 3, TTT may be used to prevent frequent frequency switching of the terminal and frequent resource allocation request/resource allocation signaling between the terminal and the base station.

Table 16 below shows example 1 of RRC asn.1 for event V2_ T1. For example, it may be set in a dedicated RRC message or system information.

[ Table 16]

In step 1105, the terminal may use the event V3_ T1 condition to select a resource pool group from the candidate resource pool groups satisfying the event V2_ T1 condition in step 1103. The event V3_ T1 may be defined as one or a combination of the following. According to an embodiment, the terminal may select the resource pool group having the lowest CBR from the candidate resource pool groups. According to another embodiment, the terminal may select the resource pool group having the lowest average CBR value from the candidate resource pool groups. According to another embodiment, the terminal may randomly select a resource pool from a pool of candidate resource pools.

In step 1107, the terminal can select a resource pool from the selected group of resources using the following event V3_ T2 condition. According to an embodiment, the terminal may select the resource pool with the lowest CBR from the selected resource pool group. According to another embodiment, the terminal may randomly select a resource pool from the selected pool of resources.

In step 1109, the terminal senses resources available for V2X communication using the selected resource pool of the selected candidate frequency (operation in mode 4), or the terminal transmits a request for resource allocation of the selected resource pool of the selected candidate frequency to the base station (operation in mode 3).

In mode 3, an operation in which the terminal makes a request to the base station for resource allocation of the selected resource pool of the selected candidate frequency is performed in the same manner as the embodiment of fig. 9.

In step 1111, if the event V2_ T1 condition in step 1103 is not satisfied, the terminal may use the resource based on the mode 3 or mode 4 with respect to the resource pool of the service frequency while maintaining the selection of the resource pool of the service frequency.

Fig. 12 illustrates a process by which a terminal uses an event V2_ T2 for CBR in scenario 3 of fig. 7, according to various embodiments of the present disclosure. In the following description, the candidate resource pool refers to a resource pool having a frequency different from a service frequency. The service frequency may be a parking frequency or may correspond to a frequency of a previously used resource pool. Further, in scenario 3 of fig. 7, when a plurality of resource pools are allocated to one component carrier, a resource pool group refers to a group of resources constituting one component carrier.

Referring to fig. 12, in step 1201, the terminal compares the CBR of the currently used resource pool group with the CBR result of the candidate resource pool group. The CBR measurement of the resource pool (coolidentity-r 14) can be reflected as CBR-PSSCH-r14 and CBR-PSCCH-r14 in RRC. Referring to Table 17 below, the values of cbr-PSSCH-r14 and cbr-PSCCH-r14 are integers from 0 to 100.

[ Table 17]

In step 1203, the terminal identifies whether the event V2_ T2 condition is satisfied. The event V2_ T2 may be defined as one of (1) a case where the CBR value of the service frequency is higher than CBR _ Threshold _ a (e.g., when the probability of occurrence of a resource conflict or resource shortage is high) and (2) a case where the CBR value of the candidate resource pool group is lower than CBR _ Threshold _ B (e.g., the probability of occurrence of a resource conflict or resource shortage is low).

The following is a condition under which the candidate resource pool group is included in the transmission resource candidates.

CBR _ servingPool > CBR _ Threshold _ A and

CBR_neighboring<CBR_Threshold_B

the CBR value (CBR _ neighbor) of the candidate resource pool group may be an average CBR value or a lowest CBR value.

A Time To Trigger (TTT) may be operated for event V2_ T2. If the event V2_ T2 is satisfied during the TTT, a pool of candidate resources is included in the transmission resource candidates. Otherwise, it is not included in the transmission resource candidates. In mode 3, TTT may be used to prevent frequent frequency switching of the terminal and frequent resource allocation request/resource allocation signaling between the terminal and the base station.

Table 18 below shows an example of RRC asn.1 for event V2_ T2. For example, it may be set in a dedicated RRC message or system information.

[ Table 18]

In step 1205, the terminal may use the event V3_ T1 condition to select a pool of resources from the candidate pools of resources that satisfy the event V2_ T2 condition in step 1203. The event V3_ T1 may be defined as one or a combination of the following. According to an embodiment, the terminal may select the resource pool group having the lowest CBR from the candidate resource pool groups. According to another embodiment, the terminal may select the resource pool group having the lowest average CBR value from the candidate resource pool groups. According to another embodiment, the terminal may randomly select a resource pool from a pool of candidate resource pools.

In step 1207, the terminal may select a resource pool from the selected group of resources using the following event V3_ T2 condition. According to an embodiment, the terminal may select the resource pool with the lowest CBR from the selected resource pool group. According to another embodiment, the terminal may randomly select a resource pool from the selected pool of resources.

In step 1209, the terminal senses resources available for V2X communication using the selected resource pool of the selected candidate frequency (operation in mode 4), or the terminal transmits a request for resource allocation of the selected resource pool of the selected candidate frequency to the base station (operation in mode 3).

In step 1211, if the event V2_ T2 condition in step 1203 is not satisfied, the terminal may use the resource based on the mode 3 or the mode 4 with respect to the resource pool of the service frequency while maintaining the selection of the resource pool of the service frequency.

Fig. 13 illustrates a process of selecting a resource pool based on mode 4 in a sub-layer inside a terminal according to various embodiments of the disclosure. Radio Resource Control (RRC), Medium Access Control (MAC), and Physical (PHY) sublayers within the terminal handle the following information and operations.

Referring to fig. 13, in step 1301, the RRC layer instructs the PHY layer to measure the CBR of the resource.

In step 1303, the PHY layer measures the CBR of the resource pool.

In step 1305, the PHY layer transmits the CBR result of the resource pool to the RRC layer.

In step 1307, the RRC layer determines whether the event is satisfied using the result of step 1305 and determines a carrier and a resource pool of the corresponding carrier. The event may correspond to at least one of the event V1_ T1, the event V1_ T2, the event V2_ T1, the event V2_ T2, the event V3_ T1, and the event V3_ T2 defined in fig. 8, 9, 10, 11, and 12. If the event for selecting the candidate resource pool is satisfied, a resource pool is determined from the candidate resource pool.

In step 1309, the RRC layer transmits information on the carrier determined in step 1307 and the resource pool of the corresponding carrier to the MAC layer.

In step 1311, the MAC layer senses resources using information about carriers received from the RRC layer and resource pools of the corresponding carriers, thereby selecting actual transmission resources.

In step 1313, the MAC layer transmits data to be transmitted to the PHY layer using the selected resources.

Fig. 14 illustrates a process of selecting a resource pool based on mode 3 in a sub-layer inside a terminal according to various embodiments of the disclosure. Radio Resource Control (RRC), Medium Access Control (MAC), and Physical (PHY) sublayers within the terminal handle the following information and operations.

Referring to fig. 14, in step 1401, the RRC layer instructs the PHY layer to measure the CBR of the resource.

In step 1403, the PHY layer measures the CBR of the resource pool.

In step 1405, the PHY layer sends the CBR result of the resource pool to the RRC layer.

In step 1407, the RRC layer determines whether the event is satisfied using the result of step 1405 and determines a carrier and a resource pool of the corresponding carrier. The event may correspond to at least one of the event V1_ T1, the event V1_ T2, the event V2_ T1, the event V2_ T2, the event V3_ T1, and the event V3_ T2 defined in fig. 8, 9, 10, 11, and 12. If the event for selecting the candidate resource pool is satisfied, a resource pool is determined from the candidate resource pool.

In step 1409, the RRC layer transmits information of the resource pools of the carriers and the corresponding carriers determined in step 1407 to the MAC layer.

In step 1411, the MAC layer transmits resource allocation request information to a base station { e.g., evolved-universal terrestrial radio access network (E-UTRAN) } based on information about carriers received from the RRC layer and a resource pool of the corresponding carrier. In this case, the actual resource allocation request information and the resource allocation information are transmitted/received through the PHY layer. The MAC layer transmits data to be transmitted to the PHY layer using the allocated resources.

Fig. 15 illustrates a process in which an event V4_ T1 is used when a terminal selects a transmission carrier in consideration of CBR and near field communication data packet priority (PPPP) in

respective scenarios

1 and 2 in fig. 5 and 6, according to various embodiments of the present disclosure. In the following description, the candidate resource pool refers to a resource pool having a frequency different from a service frequency. The service frequency refers to a resident frequency or a frequency of a previously used resource pool.

Referring to fig. 15, in step 1501, a terminal identifies PPPP of data to be transmitted. The PPPP is indexed by values of 1 to 8, and these values are determined at an upper layer, such as an application layer, a facility layer, or a PC5 signaling protocol, and then transmitted to a lower layer, such as an RRC, a Packet Data Convergence Protocol (PDCP), an RLC, a MAC, or a PHY layer.

In step 1503, the terminal may calculate CBR values for the currently used resource pool and the candidate resource pool. That is, the terminal may calculate the CBR value of the resource pool of the service frequency and the CBR value of the resource pool of the adjacent frequency. Referring to Table 19 below, the cbr-PSSCH-r14 and cbr-PSCCH-r14 values are integers from 0 to 100.

[ Table 19]

Referring to table 19, the CBR result according to pooldidentity-r 14 in the RRC layer may be identified by CBR-psch-r 14.

In step 1505, the terminal identifies whether the event V4_ T1 condition is satisfied.

In an embodiment, a CBR Threshold _ PPPP may be set for each PPPP.

For example, the CBR Threshold of PPPP1 is set to CBR _ Threshold _ a _ PPPP 1. Further, the CBR Threshold of PPPP _ X is set to CBR _ Threshold _ a _ ppppppx. In case of the PPPP1 to transmit data, the terminal may apply CBR _ Threshold _ a _ PPPP1 to the currently used resource pool and the candidate resource pool. Further, in case of pppppppx to transmit data, the terminal may apply CBR _ Threshold _ a _ pppppx to the currently used resource pool and the candidate resource pool.

As another example, the CBR Threshold of PPPP1 is set to CBR _ Threshold _ PPPP1-A and CBR _ Threshold _ PPPP 1-B. Further, the CBR Threshold for PPPP _ X is set to CBR _ Threshold _ PPPPx-A and CBR _ Threshold _ PPx-B. In the case of the PPPP1 to transmit data, the terminal may apply CBR _ Threshold _ PPPP1-a to the currently used resource pool and may apply CBR _ Threshold _ PPPP1-B to the candidate resource pool. Further, in case of pppppppx to transmit data, the terminal may apply CBR _ Threshold _ pppppx-a to the currently used resource pool, and may apply CBR _ Threshold _ pppppx-B to the candidate resource pool.

The CBR _ Threshold configuration of each PPPP may be transmitted to the terminal through system information or RRC dedicated message.

The CBR _ Threshold value for each PPPP may be set to a specific value or range of CBR values. Table 20 below shows an example in RRC asn.1, where a specific value is used as the CBR threshold.

[ Table 20]

An example of an RRC asn.1 is shown in table 21 below, in which a range of CBR values is used as the CBR threshold.

[ Table 21]

The reference tables 21, CBR-RangeList may be configured as the minimum and maximum values of the corresponding CBR ranges.

An event V4_ T1 according to an embodiment of the present disclosure may be defined as one of (1) a difference between a CBR value of a service frequency resource and a CBR value of a candidate resource pool, (2) a difference between the CBR value of the service frequency resource and the CBR value of the candidate resource pool, (3) the CBR value of the service frequency resource and the CBR value of the candidate resource pool, and (4) an event in which the service frequency resource has a lowest CBR result value.

If the CBR result for the service frequency resource of the corresponding ppppppn is greater than the CBR result for the candidate resource pool by more than CBR _ Threshold _ ppppppn, the candidate resource pool is more likely to be included in the transmission resource candidates. This corresponds to, for example, a case where the probability of occurrence of resource collision or resource shortage is high if the service frequency resource is used to transmit the packet of the corresponding PPPP.

If the CBR result of the service frequency resource of the corresponding ppppppn is greater than the CBR result of the candidate resource pool by more than CBR _ Threshold _ PPPPn, and if the CBR result of the candidate resource pool of the corresponding ppppppn is less than CBR _ Threshold _ pppn _ B, the candidate resource pool is more likely to be included in the transmission resource candidates. This corresponds to, for example, a case where the probability of occurrence of resource collision or resource shortage is high if the service frequency resource is used to transmit the packet of the corresponding PPPP.

If the CBR result of the service frequency resource of the corresponding ppppppn is greater than CBR _ Threshold _ ppppppn _ a, and if the CBR result of the candidate resource pool is less than CBR _ Threshold _ PPPPn _ B, the candidate resource pool is more likely to be included in the transmission resource candidates. This corresponds to, for example, a case where the probability of occurrence of resource collision or resource shortage is high if the service frequency resource is used to transmit the packet of the corresponding PPPP. The value of CBR _ Threshold _ ppppppn _ a and the value of CBR _ Threshold _ PPPPn _ B may be the same or different.

In the case where the CBR Threshold of the corresponding ppppppn is set to the range, if the CBR result of the service frequency resource is out of the range corresponding to CBR _ Threshold _ PPPPn compared to the CBR result of the candidate resource pool, the candidate resource pool is more likely to be included in the transmission resource candidates.

In case that the CBR Threshold of the corresponding PPPPn is set to the range, if the CBR result of the service frequency resource is out of the range corresponding to CBR _ Threshold _ pppn compared to the CBR result of the candidate resource pool, and if the CBR result of the candidate resource pool of the corresponding pppppn belongs to the range of CBR _ Threshold _ pppn _ B, the candidate resource pool is more likely to be included in the transmission resource candidates. This corresponds to, for example, a case where the probability of occurrence of resource collision or resource shortage is high if the service frequency resource is used to transmit the packet of the corresponding PPPP.

In case that the CBR Threshold of the corresponding pppppn is set to the range, if the CBR result of the service frequency resource is out of the range of CBR _ Threshold _ pppppn _ a, and if the CBR result of the candidate resource pool belongs to the range of CBR _ Threshold _ pppn _ B, the candidate resource pool is more likely to be included in the transmission resource candidates. This corresponds to, for example, a case where the probability of occurrence of resource collision or resource shortage is high if the service frequency resource is used to transmit the packet of the corresponding PPPP. The value of CBR _ Threshold _ ppppppn _ a and the value of CBR _ Threshold _ PPPPn _ B may be the same or different.

In case the CBR threshold value of the corresponding pppppn is set to the range, if the service frequency resource has the lowest CBR result value, the service frequency resource is selected. Otherwise, a candidate resource pool may be selected.

In addition to the embodiments described above, utilization (utilization) of event V4_ T1 using a particular CBR threshold or range of CBR thresholds is implemented as various embodiments.

The TTT may be operated for event V4_ T1. If the event V4_ T1 is satisfied during the TTT, the candidate resource pool is included in the transmission resource candidates. Otherwise, it is not included in the transmission resource candidates. In mode 3, TTT may be used to prevent frequent frequency switching of the terminal and frequent resource allocation request/resource allocation signaling between the terminal and the base station.

In step 1507, the terminal may select a resource pool satisfying the following event V5_ T1 condition from the selected candidate resource pools. According to an embodiment, the terminal may select a resource pool having the lowest CBR value from among the candidate resource pools. According to another embodiment, the terminal may randomly select a resource pool from the candidate resource pools.

In step 1509, the terminal may sense and select an available resource from the selected resource pool (operation in mode 4), or the terminal may transmit a request for resource allocation of the selected candidate resource pool of the selected candidate frequency to the base station (operation in mode 3).

In mode 3 or mode 4, in order to instruct the terminal to keep using the candidate frequency or the candidate resource pool for a predetermined period of time, a Transmission (TX) carrier timer may be set. The transmission carrier timer may minimize the probability of resource collision in the corresponding carrier due to frequent changes of the transmission carriers. When the terminal selects to use the candidate frequency and the resource pool of the candidate frequency instead of the service frequency and the resource pool of the service frequency, the transmission carrier timer may be specified so that the terminal may use the selected candidate frequency for a predetermined period of time, and the predetermined period of time may be set to the value of the transmission carrier timer. In another embodiment, the transmission carrier timer may be set to specify that the terminal uses the selected candidate frequency and the selected resource pool of the corresponding frequency within a predetermined time period.

In step 1511, if the event V4_ T1 condition is not satisfied in step 1503, the terminal may use the resource based on the mode 3 or mode 4 with respect to the resource pool of the service frequency while maintaining the selection of the resource pool of the service frequency.

Fig. 16 illustrates a process in which an event V4_ T2 is used when a terminal selects a transmission carrier in consideration of CBR and PPPP in scenario 3 of fig. 7, according to various embodiments of the present disclosure. In the following description, the candidate resource pool refers to a resource pool having a frequency different from a service frequency. The service frequency refers to a resident frequency or a frequency of a previously used resource pool. Further, the resource pool group refers to a group of resources constituting one component carrier in the case where a plurality of resource pools are allocated to one component carrier in scenario 3 of fig. 7.

Referring to fig. 16, the terminal identifies PPPP of data to be transmitted in step 1601. PPPP is indexed by values of 1 to 8, which are determined at an upper layer, such as an application layer, a facility layer, or a PC5 signaling protocol, and then transmitted to a lower layer, such as an RRC, PDCP, RLC, MAC, or PHY layer.

In step 1603, the terminal may calculate the CBR values for the currently used resource pool and the candidate resource pool. The CBR measurement of the resource pool (coolidentity-r 14) in RRC can be reflected by CBR-PSSCH-r14 and CBR-PSCCH-r 14. Referring to Table 22 below, the cbr-PSSCH-r14 and cbr-PSCCH-r14 values are integers from 0 to 100.

[ Table 22]

Referring to table 22, in an embodiment, the CBR value of the candidate resource pool group may be an average CBR value of the resource pools belonging to the corresponding group. In another embodiment, the CBR value of the candidate resource pool group may be the lowest CBR value among the resource pools belonging to the respective group.

In step 1605, the terminal identifies whether the event V4_ T2 condition is satisfied.

In an embodiment, a CBR Threshold _ PPPP may be set for each PPPP.

For example, the CBR Threshold of PPPP1 is set to CBR _ Threshold _ a _ PPPP 1. Further, the CBR Threshold of PPPP _ X is set to CBR _ Threshold _ a _ ppppppx. In case of the PPPP1 to transmit data, the terminal may apply CBR _ Threshold _ a _ PPPP1 to the currently used resource pool and the candidate resource pool group. Further, in case of ppppppppx to transmit data, the terminal may apply CBR _ Threshold _ a _ PPPPx to the currently used resource pool and the candidate resource pool group.

As another example, the CBR Threshold of PPPP1 is set to CBR _ Threshold _ PPPP1-A and CBR _ Threshold _ PPPP 1-B. Further, the CBR Threshold for PPPP _ X is set to CBR _ Threshold _ PPPPx-A and CBR _ Threshold _ PPx-B. In the case of the PPPP1 to transmit data, the terminal may apply CBR _ Threshold _ PPPP1-a to the currently used resource pool and may apply CBR _ Threshold _ PPPP1-B to the candidate resource pool group. Further, in case of pppppppx to transmit data, the terminal may apply CBR _ Threshold _ pppppx-a to the currently used resource pool, and may apply CBR _ Threshold _ pppppx-B to the candidate resource pool group.

The CBR _ Threshold value for each PPPP may be set to a specific value or range of CBR values. Table 23 below shows an example in RRC asn.1, where a specific value is used as the CBR threshold.

[ Table 23]

An example of an RRC asn.1 is shown in table 24 below, in which a range of CBR values is used as the CBR threshold.

[ Table 24]

The reference table 24, CBR-RangeList may be configured as the minimum and maximum values of the corresponding CBR ranges.

An event V4_ T2 according to an embodiment of the present disclosure may be defined as one of (1) a difference between a CBR value of a service frequency resource and a CBR value of a candidate resource pool group, (2) a CBR value of a candidate resource pool group, (3) a difference between a CBR of a service frequency resource and a candidate resource pool group, and a CBR value of a candidate resource pool group, (4) a CBR value of a service frequency resource and a CBR value of a candidate resource pool, and (5) an event in which a service frequency resource has a lowest CBR value.

If the CBR result for the service frequency resource of the corresponding ppppppn is greater than the CBR result for the candidate resource pool group by more than CBR _ Threshold _ ppppppn, the candidate resource pool group is more likely to be included in the transmission resource candidates. This corresponds to, for example, a case where the probability of occurrence of resource collision or resource shortage is high if the service frequency resource is used to transmit the packet of the corresponding PPPP.

If the CBR result of the service frequency resource of the corresponding ppppppn is greater than the CBR result of the candidate resource pool group by more than CBR _ Threshold _ ppppppn, and if the CBR result of the candidate resource pool group of the corresponding pppppppn is less than CBR _ Threshold _ PPPPn _ B, the candidate resource pool group is more likely to be included in the transmission resource candidates. This corresponds to, for example, a case where the probability of occurrence of resource collision or resource shortage is high if the service frequency resource is used to transmit the packet of the corresponding PPPP.

If the CBR result of the service frequency resource of the corresponding ppppppn is greater than CBR _ Threshold _ ppppppn _ a, and if the CBR result of the candidate resource pool group is less than CBR _ Threshold _ PPPPn _ B, the candidate resource pool group is more likely to be included in the transmission resource candidates. This corresponds to, for example, a case where the probability of occurrence of resource collision or resource shortage is high if the service frequency resource is used to transmit the packet of the corresponding PPPP. The value of CBR _ Threshold _ ppppppn _ a and the value of CBR _ Threshold _ PPPPn _ B may be the same or different.

In the case where the CBR Threshold of the corresponding ppppppn is set to the range, if the CBR result of the service frequency resource is out of the range corresponding to CBR _ Threshold _ PPPPn as compared to the CBR result of the candidate resource pool group, the candidate resource pool is more likely to be included in the transmission resource candidates.

In the case where the CBR Threshold of the corresponding pppppn is set to the range, if the CBR result of the service frequency resource is out of the range corresponding to CBR _ Threshold _ PPPn compared to the CBR result of the candidate resource pool group, and if the CBR result of the candidate resource pool group of the corresponding PPPn belongs to the range of CBR _ Threshold _ PPPn _ B, the candidate resource pool group is more likely to be included in the transmission resource candidates. This corresponds to, for example, a case where the probability of occurrence of resource collision or resource shortage is high if the service frequency resource is used to transmit the packet of the corresponding PPPP.

In the case where the CBR Threshold of the corresponding pppppn is set to the range, if the CBR result of the service frequency resource is out of the range of CBR _ Threshold _ pppppn _ a, and if the CBR result of the candidate resource pool group belongs to the range of CBR _ Threshold _ pppn _ B, the candidate resource pool group is more likely to be included in the transmission resource candidates. This corresponds to, for example, a case where the probability of occurrence of resource collision or resource shortage is high if the service frequency resource is used to transmit the packet of the corresponding PPPP. The value of CBR _ Threshold _ ppppppn _ a and the value of CBR _ Threshold _ PPPPn _ B may be the same or different.

In addition to the embodiments described above, the utilization of events V4_ T2 using a particular CBR threshold or range of CBR thresholds may be implemented into various embodiments.

The TTT may be operated for event V4_ T2. If the event V4_ T2 is satisfied during the TTT, the candidate resource pool is included in the transmission resource candidates. Otherwise, it is not included in the transmission resource candidates. In mode 3, TTT may be used to prevent frequent frequency switching of the terminal and frequent resource allocation request/resource allocation signaling between the terminal and the base station.

In step 1607, the terminal may use the event V5_ T2 condition to select one resource pool from among the resource pool candidates satisfying the event V4_ T2 condition in step 1605. The event V5_ T2 may be defined as one or a combination of the following. According to an embodiment, the terminal may select the resource pool group having the lowest CBR from the candidate resource pool groups. According to an embodiment, the terminal may select the resource pool group with the lowest average CBR from the candidate resource pool groups. According to another embodiment, the terminal may randomly select a pool of resource pools from the candidate pool of resource pools.

In step 1609, the terminal may select a resource pool from the selected resource pool group using the event V6_ T1 condition. According to an embodiment, the terminal may select the resource pool with the lowest CBR from the selected resource pool group. According to another embodiment, the terminal may randomly select a resource pool from the selected pool of resources.

In step 1611, the terminal may sense resources available for V2X communication using the selected resource pool of the selected candidate frequency (operation in mode 4), or the terminal may transmit a request for resource allocation of the selected candidate resource pool of the selected candidate frequency to the base station (operation in mode 3).

In step 1613, if the event V4_ T2 condition is not satisfied in step 1605, the terminal may use the resource based on the mode 3 or mode 4 with respect to the resource pool of the service frequency while maintaining the selection of the resource pool of the service frequency.

Fig. 17 illustrates a process of selecting a resource pool based on mode 4 according to the embodiments in fig. 15 and 16 in a sub-layer inside a terminal according to various embodiments of the present disclosure. The RRC, MAC and PHY sublayers within the terminal handle the following information and operations.

Referring to fig. 17, in step 1701, the RRC layer instructs the PHY layer to measure the CBR of the resource.

In step 1703, the PHY layer measures the CBR of the resource pool.

In step 1705, the PHY layer sends the CBR result of the resource pool to the RRC layer.

In step 1707, the RRC layer determines whether the event is satisfied using the result of step 1705 and determines a carrier and a resource pool of the corresponding carrier. The event may correspond to at least one of the event V4_ T1, the event V4_ T2, the event V5_ T1, the event V5_ T2, the event V6_ T1, and the event V6_ T2 defined in fig. 15 and 16. If the event for selecting the candidate resource pool is satisfied, a resource pool is determined from the candidate resource pool.

In step 1709, the RRC layer transmits information on the carriers determined in step 1707 and the resource pool of the corresponding carriers to the MAC layer.

In step 1711, the MAC layer senses resources using information about carriers and resource pools of the corresponding carriers received from the RRC layer and selects actual transmission resources.

In step 1713, the MAC layer transmits data to be transmitted to the PHY layer using the selected resources.

Fig. 18 illustrates a process of selecting a resource pool based on mode 3 according to the embodiments in fig. 15 and 16 in a sub-layer inside a terminal according to various embodiments of the present disclosure. The RRC, MAC and PHY sublayers within the terminal handle the following information and operations.

Referring to fig. 18, in step 1801, the RRC layer instructs the PHY layer to measure the CBR of the resource.

In step 1803, the PHY layer measures the CBR of the resource pool.

In step 1805, the PHY layer sends the CBR result of the resource pool to the RRC layer.

In step 1807, the RRC layer determines whether the event is satisfied using the result of step 1805 and determines a carrier and a resource pool of the corresponding carrier. The event may correspond to at least one of the event V4_ T1, the event V4_ T2, the event V5_ T1, the event V5_ T2, the event V6_ T1, and the event V6_ T2 defined in fig. 15 and 16. If the event for selecting the candidate resource pool is satisfied, a resource pool is determined from the candidate resource pool.

In step 1809, the RRC layer transmits information on the carriers determined in step 1807 and the resource pool of the corresponding carriers to the MAC layer.

In step 1811, the MAC layer transmits resource allocation request information to a base station (e.g., E-UTRAN) based on the information on the carriers and the resource pools of the corresponding carriers received from the RRC layer. In this case, the actual resource allocation request information and the resource allocation information are transmitted/received through the PHY layer. The MAC layer transmits data to be transmitted to the PHY layer using the allocated resources.

Fig. 19 illustrates a process in which a terminal selects a transmission carrier in a case where data replication and transmission are applied using multiple carriers, according to various embodiments of the present disclosure.

Referring to fig. 19, when generating data to be transmitted, the terminal may identify the corresponding data (i.e., the type of application) in step 1901. The data type information may be utilized to determine whether data replication using multiple transmission carriers is necessary. In an embodiment, the type of data that requires data replication may be identified based on a value { e.g., PPPP or ProSe Reliability Per Packet (PRPP) } set by an upper layer, such as an application layer, a facility layer, or a ProSe layer. In another embodiment, the type of data that needs data replication may be identified based on an application ID set by an upper layer.

In step 1903, the terminal may determine whether data to be transmitted needs to be copied and transmitted. The conditions requiring data replication and transmission are the same as in the following embodiments.

For example, PPPP may be used.

In an embodiment, a dedicated PPPP index may be specified, which requires data replication. For example, it may be specified that data copy is performed when PPPP is 1, and when a packet whose PPPP is 1 is transmitted, the terminal determines that it is necessary to copy the packet to a plurality of carriers. An example of RRC asn.1 is shown in table 25 below to inform the dedicated PPPP index to which data replication is to be applied.

[ Table 25]

priorityThreshold-r14 SL-Priority-r13，

In another embodiment, the terminal may be configured to apply data copying if the PPPP value of the packet to be transmitted is set to a value outside the general range of PPPP values. For example, when the general range of PPPP values is set to a value of 1 to 8, data copying may be performed with respect to a packet having a PPPP value other than the value of 1 to 8. When transmitting a packet of PPPP 10, the terminal may determine that it is necessary to copy the packet to a plurality of carriers.

As another example, PRPP may be used.

In an embodiment, in case that the PRPP flag is set to 'data copy On (On'), the terminal may determine that it is necessary to copy data to a plurality of carriers.

In another embodiment, the terminal may be configured to apply data copying if the PRPP value of the packet to be transmitted is set to a value outside the general range of PRPP values. For example, when the general range of the PRPP value is set to a value of 1 to 8, data copying may be performed with respect to a packet having a PRPP value other than the value of 1 to 8. When transmitting a packet with PRPP of 10, the terminal may determine that it is necessary to copy the packet to a plurality of carriers.

If it is determined in step 1903 that the packet to be transmitted needs to be copied, the terminal may select a carrier for packet copying and transmission and a resource pool of the corresponding carrier. In various embodiments of the present disclosure, a resource selection method using at least one of CBR, PPPP, and PRPP may be used.

In step 1905, the terminal may select a candidate frequency and a candidate resource pool of corresponding frequencies using one of the following embodiments in order to select resources for replication.

In an embodiment, the terminal may compare the CBRs of the candidate resources and may select transmission carriers for data replication and transmission in order of frequency resource pools from the lowest CBR value to the highest CBR value. For example, if the CBR values are ordered (rank) in the order of carrier 1 resource pool 1< carrier 2 resource pool 1< carrier 3 resource pool1, carrier 1 resource pool1 and carrier 2 resource pool1 are selected when data replication is performed using two transmission carriers.

If there is only one resource pool for each frequency, the selection of the TX carrier on which to perform data replication is determined according to CBR ranking (ranking) between frequencies. If there are multiple resource pools for each frequency, the resource pool with the lowest CBR ordering is selected for each frequency, and the selection of the transmission carrier on which to perform the data replication is determined according to the CBR ordering between the resource pools of the respective selected frequencies.

In another embodiment, the terminal may compare the CBR of the candidate resource with CBR _ PPPP _ Threshold (i.e., a CBR Threshold corresponding to the PPPP index of the packet to be transmitted) (see the embodiments in fig. 15 and 16), and may select the transmission carriers for data replication in order of frequency resource pools from the lowest CBR value to the highest CBR value with respect to the resource pools satisfying the frequencies of CBR _ PPPP _ Threshold and the corresponding frequencies. For example, if carrier 1 resource pool1, carrier 2 resource pool2, and carrier 3 resource pool3 are selected that satisfy CBR _ PPPP _ Threshold, then it may be assumed that the CBR values for the selected resources are ordered as carrier 1 resource pool 1< carrier 2 resource pool 1< carrier 3 resource pool 1. In this case, when data replication is performed using two transmission carriers, the terminal may select carrier 1 resource pool1 and carrier 2 resource pool 1.

If there is one resource pool for each frequency, the terminal may measure the CBR value of the one resource pool to determine whether CBR _ PPPP _ Threshold is satisfied for each frequency. Thereafter, the terminal may select a transmission carrier on which data replication is performed and a resource pool of a corresponding carrier according to the CBR value ranking of the resource pools satisfying the frequency of CBR _ PPPP _ Threshold. If there are a plurality of resource pools for each frequency, the terminal may select a resource pool satisfying CBR _ PPPP _ Threshold from among the plurality of resource pools for each frequency, and may select a transmission carrier on which data replication is performed and a resource pool of a corresponding carrier according to the CBR value ordering of each resource pool satisfying CBR _ PPPP _ Threshold.

In another embodiment, the terminal may compare the CBR of the candidate resource with CBR _ PRPP _ Threshold (i.e., a CBR Threshold corresponding to a PRPP index of a packet to be transmitted) (embodiments using PRPP in fig. 15 and 16 may be utilized), and may select a transmission carrier for performing data replication in order of a frequency resource pool from a lowest CBR value to a highest CBR value with respect to a resource pool satisfying the frequency of CBR _ PRPP _ Threshold and a corresponding frequency. For example, if carrier 1 resource pool1, carrier 2 resource pool2, and carrier 3 resource pool3 are selected that satisfy CBR _ PRPP _ Threshold, it can be assumed that the CBR values for the selected resources are ordered as carrier 1 resource pool 1< carrier 2 resource pool 1< carrier 3 resource pool 1. In this case, when data replication is performed using two transmission carriers, the terminal may select carrier 1 resource pool1 and carrier 2 resource pool 1.

In step 1907, the terminal may transmit the original packet and the duplicate packet using a plurality of selected frequencies and a resource pool of corresponding frequencies. In an embodiment, the packet duplication may correspond to duplication of PDCP packets.

In step 1909, the terminal may perform transmission of a single piece of data using a currently used frequency and a resource pool of a corresponding frequency or using a newly selected frequency and a resource pool of a corresponding frequency. In another embodiment of the operation of the terminal selecting multiple transmission carrier resources for data replication, the terminal may use the serving frequency (the camping frequency or the frequency of the previously used resource pool) as the transmission carrier and may select the remaining transmission carriers to send the replicated data using step 1905.

Now, a procedure in which the terminal operates the transmission carrier timer proposed in the present disclosure will be described with reference to fig. 20 and 21. The transmission carrier timer may be applied to the selection of the transmission carriers and resource pools in fig. 8 to 18.

Fig. 20 illustrates a process of a terminal initiating operation of a Transmit (TX) carrier timer according to various embodiments of the present disclosure.

The transmission carrier timer may be used to identify whether a change of transmission carrier is possible. In an embodiment, if the terminal selects to use the candidate frequency and the resource pool of candidate frequencies instead of the service frequency and the resource pool of service frequencies, the terminal may be designated to use the selected candidate frequency for a predetermined period of time, and the predetermined period of time may be set to the value of the transmission carrier timer. In another embodiment, the transmission carrier timer may be set to specify that the terminal uses the selected candidate frequency and the selected resource pool of the corresponding frequency within a predetermined time period. If the transmission carrier timer is set, the terminal does not change the transmission carrier or the selected resource pool of the transmission carrier.

Referring to fig. 20, in step 2001, the terminal may perform a process of selecting a transmission carrier and a resource pool. The process of selecting a transmission carrier may be performed using the methods described in fig. 8 to 18.

In step 2003, when the terminal changes the transmission carrier from the serving transmission carrier to another transmission carrier, if the transmission carrier timer is not set at this time, the terminal may proceed to step 2005 to set the transmission carrier timer. On the other hand, if the terminal uses a resource pool in the service transmission carrier, the terminal may proceed to step 2001.

The terminal having set the transmission carrier timer in step 2005 can perform the procedure of fig. 21.

Fig. 21 illustrates a process for a terminal to operate a transmit carrier timer according to various embodiments of the present disclosure.

Referring to fig. 21, in step 2101, the terminal may initiate the setting of a transmission carrier timer when changing resources from a serving transmission carrier to a resource pool of another transmission carrier. For example, according to the embodiment in fig. 20, the terminal may initiate the setting of the transmission carrier timer.

In step 2103, if the currently used transmission carrier timer expires, the terminal may proceed to step 2105. Otherwise, the terminal may proceed to step 2107.

In step 2105, the terminal may determine an operation allowing the change of the transmission carrier to another transmission carrier other than the currently used transmission carrier as needed without setting the transmission carrier timer.

In step 2107, the terminal may maintain a previously set transmission carrier timer and may determine that an operation of changing the transmission carrier to another transmission carrier other than the currently used transmission carrier is not allowed.

Fig. 22 illustrates signal flows in which a terminal receives from a base station a Transmission (TX) carrier selection configuration to be applied to selection of a transmission carrier and a resource pool of the respective carrier, according to various embodiments of the present disclosure.

Referring to fig. 22, in step 2201, a base station 101 may transmit configuration information for selecting a transmission carrier and a resource pool of a corresponding carrier to a terminal 121. The configuration information may be transmitted through system information or RRC dedicated signaling.

An example of configuration information for transmission carrier selection transmitted from base station 101 to terminal 121 is as follows. (1) Frequency ID, (2) resource pool ID, (3) resource pool information, (4) Transmission (TX) carrier and resource pool selection event type information, and CBR threshold information, and (5) Transmission (TX) carrier timer.

Here, (2) the resource pool ID indicates an ID of the resource pool, and may have a unique value for all frequencies or may have a unique value by being used together with the frequency ID.

(3) The resource pool information indicates a location of the resource pool. For example, it represents frequency, time resource information, etc. of the resource pool.

(4) The TX resource selection event type includes at least one piece of information about an event V1_ T1, an event V1_ T2, an event V2_ T1, an event V2_ T2, an event V3_ T1, an event V3_ T2, an event V4_ T1, an event V4_ T2, an event V5_ T2, or an event V6_ T1.

(4) The CBR threshold information includes at least one piece of information on a specific value, a range of CBR values, a threshold value of each PPPP, and a CBR threshold value of each PRPP.

(5) The transmit carrier timer has a transmit carrier timer setting. For example, if the transmission carrier timer is set to 1000ms, the terminal 121 does not perform an operation of selecting another transmission carrier other than the currently used transmission carrier 1000ms after the start of the transmission carrier timer.

In step 2203, the terminal 121 may perform an operation of selecting resources of a transmission carrier and a corresponding carrier according to various embodiments of the present disclosure using a Transmission (TX) carrier selection configuration set by the base station 101.

The embodiment in fig. 22 may be used to select a transmission carrier and resource pool for transmission of a single packet. Next, with reference to fig. 23, an embodiment of setting transmission carrier selection, which can be used to select a transmission carrier and a resource pool for packet replication and transmission, will be described.

Fig. 23 illustrates signal flows in which a terminal receives configuration information for Transmission (TX) resource selection for data replication from a base station, according to various embodiments of the disclosure.

Referring to fig. 23, in step 2301, the base station 101 may transmit configuration information for selecting a transmission carrier on which packet replication and transmission are performed and a resource pool of the corresponding carrier. The configuration information may be transmitted through system information or RRC dedicated signaling.

An example of configuration information of TX carrier selection for duplication of a packet transmitted from the base station 101 to the terminal 121 is as follows. (1) Frequency ID, (2) resource pool ID, (3) resource pool information, and (4) TX carrier and resource pool selection event type information for packet replication, PRPP threshold information, and CBR threshold information.

(4) The PPPP threshold information refers to PPPP reference information for determining packet duplication and transmission with respect to a plurality of carriers.

(4) The PRPP threshold information refers to PRPP reference information for determining packet duplication and transmission with respect to a plurality of carriers.

(4) The CBR threshold information refers to a specific value, a range of CBR values, a CBR threshold per PPPP, and a CBR threshold per PRPP.

In step 2303, the terminal 121 may perform an operation of selecting resources of a transmission carrier and a corresponding carrier according to various embodiments of the present disclosure using a TX carrier selection configuration for packet replication set by the base station 101.

Another embodiment of the transmission carrier selection configuration information for packet duplication described above in fig. 19 to 23 is as follows.

The TX parameter, the duplication indicator, or the Channel Busy Ratio (CBR) index may be used as a configuration parameter for selecting or reselecting a carrier for packet duplication based on PRPP, CBR, or PPPP, which may be represented as table 26 or table 27 below.

In an embodiment, the following is a case where a transmission parameter determined based on the PPRP and the CBR is used as a parameter for selecting or reselecting a carrier for packet duplication. In case that a selection indicator or a reselection indicator, which is a corresponding indicator, is included in the transmission parameters, the indicator may be used as a condition for carrier selection and reselection. For example, if the selection indicator of the transmission parameters is set to true, the V2X terminal may perform a carrier selection operation based on the PRPP and CBR of the V2X data to be transmitted. Alternatively, if the selection indicator of the transmission parameter is set to false, the V2X terminal may not perform a carrier selection operation. Further, if a reselection indicator is included in the transmission parameters, whether to perform a carrier reselection operation may be determined in the same manner as the example of the selection indicator. In another embodiment, the maximum power value of the transmission parameter may be used as a condition for carrier selection and reselection, as described below. If the maximum power of the transmission parameter selected based on the PRPP and CBR of the V2X data to be transmitted is set to zero, the V2X terminal may not transmit the V2X data through the corresponding carrier and may transmit the V2X data by selecting another carrier. At this time, for example, the V2X terminal may select a resource for which the maximum power of a transmission parameter of another carrier is not zero, or may select a resource having the lowest CBR from among resources for which the maximum power is not zero, thereby transmitting V2X data.

Another embodiment including a selection indicator or reselection indicator when PRPP and CBR are used as parameters to select or reselect carriers for packet replication is as follows. The V2X terminal may select the selection indicator using the CBR result of the measured channel environment and the PRPP of the V2X data to be transmitted. For example, if the selection indicator is set to true with respect to the CBR of the channel and the PRPP of the packet to be transmitted, the V2X terminal may perform a carrier selection operation. As another example, if the selection indicator is set to false with respect to the CBR of the channel and the PRPP of the packet to be transmitted, the V2X terminal may not perform a carrier selection operation. Similarly, where the reselection indicator is for carrier reselection, it may be determined whether the reselection indicator is set to true or false with respect to the CBR of the channel and the PRPP of the packet to be transmitted, such that a carrier reselection operation may or may not be performed.

Another embodiment including a selection indicator or reselection indicator when the CBR index is used as a parameter to select or reselect a carrier is as follows. The CBR index may be determined using the CBR result of the channel measured by the V2X terminal and the PRPP of the V2X data to be transmitted. As an example of using the CBR index to select a carrier, the V2X terminal may determine the CBR index using the CBR result and the PRPP. The V2X terminal may perform a carrier selection operation if the selection indicator or reselection indicator of the selected CBR index is true. Alternatively, if the selection indicator of the selected CBR index is false, the V2X terminal may not perform a carrier selection operation. Similarly, in the case where the reselection indicator is used for carrier reselection, it may be determined whether the reselection indicator of the CBR index determined based on the CBR of the channel and the PRPP of the packet to be transmitted is set to true or false, so that a carrier reselection operation may or may not be performed.

Although the above description has been made based on CBR and PRPP, the same operation can be applied to the case of PPPP using a packet to be transmitted.

[ Table 26]

Table 26 shows that a Transmission (TX) parameter, a selection indicator, a reselection indicator, or a CBR index corresponding to a CBR range of a channel and a PRPP of a packet is used as information for selecting or reselecting a carrier for packet duplication. The information for selecting or reselecting a carrier for packet duplication may be a specific Transmission (TX) parameter or a selection indicator/reselection indicator mapped with the transmission parameter, or may be a specific CBR index or a selection indicator/reselection indicator mapped with the CBR index. The V2X terminal may determine the parameters in table 26 based on the PRPP and CBR and may apply them to the selection or reselection of carriers for packet replication.

[ Table 27]

Table 27 shows that a Transmission (TX) parameter, a selection indicator, a reselection indicator, or a CBR index corresponding to a CBR range of a channel and a PPPP of a packet is used as information for selecting or reselecting a carrier for packet duplication. The information for selecting or reselecting a carrier for packet duplication may be a specific Transmission (TX) parameter or a selection indicator/reselection indicator mapped with the transmission parameter, or may be a specific CBR index or a selection indicator/reselection indicator mapped with the CBR index. The V2X terminal may determine the parameters in table 27 based on PPPP and CBR and may apply them to selection or reselection of carriers for packet replication.

Further, as an embodiment of a selection indicator or reselection indicator for selecting or reselecting a carrier for packet duplication, a candidate resource pool may be selected in the MAC layer using events according to the embodiments in fig. 8, 10 to 12, 15, 16, and 19 described above or using tables 28 to 41 described later. According to various embodiments of the present disclosure, in the case of using CBR, in the method of using tables 28 to 41 described later, carrier selection and reselection may be determined by comparing a previous CBR value of a currently used carrier with a currently used CBR value thereof, or may be determined using a current CBR value of a currently used carrier and a current CBR value of a candidate carrier.

Now, an embodiment of an operation of a V2X terminal for selecting a transmission carrier and an embodiment of an operation of a V2X terminal for reselecting a transmission carrier will be described, respectively, according to various embodiments of the present disclosure.

Fig. 24A illustrates an example of initial operation of a V2X terminal for selecting a transmission carrier according to various embodiments of the present disclosure.

In step 2401, the V2X terminal may obtain resource pool information allocated to each carrier from information received from the base station or pre-configuration information stored in the V2X terminal. The resource pool information may be stored as RRC information and may be transmitted to the MAC layer.

In step 2403, the V2X terminal selects a candidate resource pool from among the resource pools allocated to each carrier. In an embodiment, the candidate resource pool may be selected based on CBR measurements of the resource pool allocated to each carrier and PPPP of V2X data to be transmitted by the terminal. At this time, the candidate resource pool may be selected in the MAC layer using events according to the embodiments in fig. 8, 10 to 12, 15, 16, and 19 described above or using tables 28 to 41 described later.

In step 2405, the V2X terminal selects one resource pool from the candidate resource pools selected in step 2403. As an example, the V2X terminal may select one resource pool with the lowest CBR, or may randomly select one resource pool from among the candidate resource pools.

In step 2407, the V2X terminal may select a transmission resource through a sensing operation in one of the resource pools selected in step 2405.

In step 2409, the V2X terminal may transmit V2X data using the transmission resources selected in step 2407.

Fig. 24B illustrates an example of operations for a V2X terminal to reselect a transport carrier according to various embodiments of the present disclosure. Here, it is assumed that the V2X terminal has completed the operation of selecting a transmission carrier according to the embodiment in fig. 24A described above.

In the embodiment of fig. 24B, the V2X terminal may obtain resource pool information allocated to each carrier from information received from the base station or pre-configuration information stored in the V2X terminal. The resource pool information may be stored as RRC information and may be transmitted to the MAC layer.

In step 2411, the V2X terminal may identify whether conditions for reselecting transmission resources (i.e., transmission carriers, transmission resource pools, etc.) are satisfied. The operation of step 2411 may correspond to a case where data to be transmitted remains in the terminal buffer. The operation of step 2411 may correspond to a case where the terminal has pre-selected transmission carriers and resource pool information.

An example of satisfying the condition in step 2411 may be a case where SL _ RESOURCE _ reset _ COUNT is zero. SL _ RESOURCE _ reset _ COUNT is a value used to determine whether to maintain or reselect the V2X data transmission RESOURCE and is decremented by 1 for each V2X data transmission. If SL _ RESOURCE _ RESELEMENT _ COUNT is zero, the V2X terminal may reselect the V2X data transmission RESOURCE. If SL _ RESOURCE _ reset _ COUNT is not zero, the V2X terminal may send V2X data using the existing RESOURCEs. Another embodiment satisfying the condition in step 2411 may be a case where the V2X terminal does not transmit data within a predetermined time period or a predetermined number of times even though the V2X terminal has obtained transmission resources. Another embodiment in which the condition in step 2411 is met may be where the V2X terminal does not meet the delay requirements or terminal RF requirements when transmitting packets using the selected resources. Another embodiment in which the condition in step 2411 is satisfied may be the case where the transmission carrier timer of fig. 20 and 21 expires. For example, if the transport carrier timer is running, the V2X terminal may not perform a carrier reselection operation. For example, if the transport carrier timer expires, the V2X terminal may perform a carrier reselection operation.

In step 2413, the V2X terminal may identify a carrier reselection indicator to determine whether the carrier reselection condition is satisfied. If, as a result of the determination in step 2413, the carrier reselection condition is satisfied, the V2X terminal may proceed to step 2415. Otherwise, the V2X terminal may proceed to step 2419. Examples of carrier reselection indicators may refer to the selection indicators in tables 28 through 30 and 34 through 36 or the reselection indicators in tables 31 through 33 and 37 through 41.

In step 2415, the V2X terminal may select a candidate resource pool from among the resource pools allocated to each carrier. In an embodiment, the candidate resource pool may be selected based on CBR measurements of the resource pool allocated to each carrier and PPPP of V2X data to be transmitted by the terminal. At this time, the candidate resource pool may be selected in the MAC layer using events according to the embodiments in fig. 8, 10 to 12, 15, 16, and 19 described above or using tables 28 to 41 described later.

In step 2417, the V2X terminal may select one or more resources for each carrier as a candidate resource pool using the method in step 2415. The V2X terminal may select one of the resource pools having the lowest CBR or may randomly select one of the candidate resource pools.

In step 2419, the V2X terminal may select a resource by performing a sensing operation for selecting a transmission resource from the resource pool. The resource pool of step 2419 may be a resource pool used in previous packet transmissions or may be a resource pool reselected by the operations of

steps

2415 and 2417.

In step 2421, if the condition for reselecting transmission RESOURCEs is not satisfied in step 2411 (e.g., SL _ RESOURCE _ reset _ COUNT is not zero), the V2X terminal may maintain the RESOURCEs for packet transmission.

In step 2423, the V2X terminal may transmit V2X data using the determined resources. If SL _ RESOURCE _ RESELEMENT _ COUNT is being used by the V2X terminal, the V2X terminal decrements the SL _ RESOURCE _ RESELEMENT _ COUNT value by 1. Thereafter, if there is V2X data to be transmitted, the V2X terminal may proceed to the operation of step 2411.

In the case where the new RESOURCE pool setting for each carrier is transferred from the RRC of the V2X terminal to the MAC layer, if SL _ RESOURCE _ reset _ COUNT is zero, the V2X terminal may perform the operation of step 2413.

Although in the embodiment of fig. 24B, the operations of steps 2411 to 2415 are described as separate steps for carrier and resource pool reselection, the operations of steps 2411 to 2415 may be configured as one step for carrier and resource pool reselection. That is, the V2X terminal may use the information of step 2415 to determine whether the carrier and resource pool reselection conditions are met, step 2415 using events according to the embodiments in fig. 8, 10 to 12, 15, 16 and 19 described above, or using tables 28 to 41 described later, including the various resource reselection conditions of step 2411 and the selection/reselection indicator of step 2413.

Fig. 24C illustrates another example of operation of the V2X terminal to reselect a transport carrier according to various embodiments of the present disclosure. It is assumed that the V2X terminal has completed the operation of selecting a transmission carrier according to the embodiment in fig. 24A described above.

In the embodiment of fig. 24C, the V2X terminal may obtain resource pool information allocated to each carrier from information received from the base station or pre-configuration information stored in the V2X terminal. The resource pool information may be stored as RRC information and may be transmitted to the MAC layer.

In step 2425, the V2X terminal may identify whether a condition for reselecting transmission resources (i.e., transmission carriers, transmission resource pools, etc.) is satisfied. The operation of step 2425 may correspond to the case where data to be transmitted remains in the terminal buffer. The operation of step 2425 may correspond to the case where the terminal has pre-selected transmission carriers and resource pool information.

An example of satisfying the condition in step 2425 may be when SL _ RESOURCE _ reset _ COUNT is zero. SL _ RESOURCE _ reset _ COUNT is a value used to determine whether to maintain or reselect the V2X data transmission RESOURCE and is decremented by 1 for each V2X data transmission. If SL _ RESOURCE _ RESELEMENT _ COUNT is zero, the V2X terminal may reselect the V2X data transmission RESOURCE. If SL _ RESOURCE _ reset _ COUNT is not zero, the V2X terminal may send V2X data using the existing RESOURCEs. Another embodiment in which the condition in step 2425 is satisfied may be a case in which the V2X terminal does not transmit data within a predetermined time period or a predetermined number of times even though the V2X terminal has obtained transmission resources. Another embodiment in which the condition in step 2425 is met may be where the V2X terminal does not meet the delay requirement or terminal RF requirement when transmitting packets using the selected resources. Another embodiment in which the condition in step 2425 is satisfied may be the case where the transmission carrier timer in fig. 20 and 21 expires. For example, if the transport carrier timer is running, the V2X terminal may not perform a carrier reselection operation. For example, if the transport carrier timer expires, the V2X terminal may perform a carrier reselection operation.

In step 2427, the V2X terminal may select a candidate resource pool from among the resource pools allocated to each carrier. In an embodiment, the candidate resource pool may be selected based on CBR measurements of the resource pool allocated to each carrier and PPPP of V2X data to be transmitted by the terminal. At this time, the candidate resource pool may be selected in the MAC layer using events according to the embodiments in fig. 8, 10 to 12, 15, 16, and 19 described above or using tables 28 to 41 described later. Examples of carrier reselection indicators used in step 2427 may refer to the selection indicators in tables 28 through 30 and 34 through 36 or the reselection indicators in tables 31 through 33 and 37 through 41.

In step 2429, the V2X terminal may select one or more resources for each carrier as a candidate resource pool using the method in step 2427. The V2X terminal may select one of the resource pools having the lowest CBR or may randomly select one of the candidate resource pools.

In step 2431, the V2X terminal may select a resource by performing a sensing operation for selecting a transmission resource from the resource pool. The resource pool of step 2431 may be a resource pool used in previous packet transmission or may be a resource pool reselected by the operations of

steps

2427 and 2429.

If the condition for reselecting transmission RESOURCEs is not satisfied in step 2425 (e.g., SL _ RESOURCE _ reset _ COUNT is not zero), the V2X terminal may maintain the RESOURCEs used for packet transmission in step 2433.

In step 2435, the V2X terminal may transmit V2X data using the determined resources. If SL _ RESOURCE _ RESELEMENT _ COUNT is being used by the V2X terminal, the V2X terminal decrements the SL _ RESOURCE _ RESELEMENT _ COUNT value by 1. Thereafter, if there is V2X data to be transmitted, the V2X terminal may proceed to the operation of step 2425.

In the case where the new RESOURCE pool setting for each carrier is transferred from the RRC of the V2X terminal to the MAC layer, if SL _ RESOURCE _ reset _ COUNT is zero, the V2X terminal may perform the operation of step 2427.

Although in the embodiment of fig. 24C, the operations of steps 2425 through 2427 are described as separate steps for carrier and resource pool reselection, the operations of steps 2425 through 2427 may be configured as one step for carrier and resource pool reselection. That is, the V2X terminal may use the information of step 2427 to determine whether the carrier and resource pool reselection conditions are satisfied, step 2427 using events according to the embodiments in fig. 8, 10 to 12, 15, 16 and 19 described above, or using tables 28 to 41 described later, including the various resource reselection conditions of step 2425 and the selection/reselection indicator of step 2427.

Now, tables 28 to 41 will be described showing CBR or PPPP indication information that a V2X terminal may use in selecting carriers and resource pools according to various embodiments of the present disclosure. The embodiments of tables 28 to 41 may be applied to the operation of step 2403 in fig. 24A, step 2415 in fig. 24B, or step 2427 in fig. 24C.

Tables 28 to 41 show the case where the CBR-PPPP table applied to the resource pool is used, according to various embodiments of the present disclosure. According to tables 28 to 41, the V2X terminal may select the candidate resource pool by carrier selection or reselection conditions based on CBR-PPPP using the carrier selection indicator. The carrier selection indicator is used as a condition for determining an available carrier in an operation of selecting a carrier (i.e., step 2403 in fig. 24A) and in an operation of reselecting a carrier (i.e., step 2415 in fig. 24B or step 2427 in fig. 24C).

Table 28 shows an example in which carrier selection indicators are set for some CBR-PPPP ranges. In the case where the carrier selection indicator is set for a specific CBR-PPPP range, the operation of the same indicator (e.g., carrier selection or reselection condition) may be applied to CBR-PPPP ranges beyond the specific CBR-PPPP range as a reference. As another example, the same indicator operation may be applied to CBR ranges that are beyond the reference CBR range. As another example, the operation of the same indicator may be applied to a PPPP range that is beyond the reference PPPP range. For example, if the selection indicator is set to true in CBR range 1 and parameter PPPP1, the V2X terminal operates as follows. Assuming that the CBR measured by the V2X terminal is within CBR range 2, the PPPP of the V2X data to be transmitted is 1. In this case, because the selection indicators of CBR range 1 and PPPP1 are set to true, the V2X terminal may determine that the conditions of CBR range 2 and PPPP1 satisfy the conditions for performing carrier selection or reselection operations for V2X data transmission.

[ Table 28]

Table 29 shows an example in which carrier selection indicators are set for all CBR-PPPP ranges. In the case where the carrier selection indicator is set within the CBR-PPPP range, the carrier selection indicator within the corresponding CBR-PPPP range may be used as a condition for determining carrier selection or reselection. For example, if the selection indicator is set to true under the conditions of CBR range 1 and parameter PPPP1, the V2X terminal operates as follows. For example, in the case where the CBR result measured by the V2X terminal is within CBR range 1 and the PPPP of the V2X data to be transmitted is 1, the terminal refers to the CBR range 1 and the value of the selection indicator of the PPPP1 and performs a carrier selection or reselection operation if it is set to true. For example, in the case where the CBR result measured by the V2X terminal is within CBR range 1 and the PPPP of V2X data to be transmitted is 1, the terminal refers to the CBR range 1 and the value of the selection indicator of the PPPP1, and does not perform a carrier selection or reselection operation if the selection indicator is set to false.

[ Table 29]

An example of RRC signaling including the information of the above tables 28 and 29 is as follows. As an embodiment of RRC asn.1, the selection indicator may be included in the SL-CBR-PPPP-TxConfigList shown in table 30. Table 30 shows an embodiment of the SL-CBR-PPPP-TxConfigList information component.

[ Table 30]

As an indicator to indicate carrier selection or reselection, the selection indicator of Tx-ConfigList-r15 may be set to true or false. As in the embodiments of tables 28 and 29, the selection indicator may be combined with a priority threshold (priority threshold) or CBR configuration index (CBR-ConfigIndex) and then may be used as a carrier selection or reselection condition.

According to various embodiments of the present disclosure, the candidate resource pool may be selected using the selection indicator or reselection indicator in tables 31 and 32 below. The selection indicator is used to determine carriers available for V2X terminals when the V2X terminals select the carriers. When the V2X terminal uses the selected carrier, the reselection indicator is used to reselect the carrier.

Table 31 shows an example in which a selection indicator or reselection indicator is set for some CBR-PPPP ranges. In the case where the carrier selection indicator or the carrier reselection indicator is set for a specific CBR-PPPP range, the operation of the same indicator (e.g., carrier selection or reselection condition) may be applied to CBR-PPPP ranges beyond the specific CBR-PPPP range as a reference. As another example, the same indicator operation may be applied to CBR ranges that are beyond the reference CBR range. As another example, the operation of the same indicator may be applied to a PPPP range that is beyond the reference PPPP range.

For example, if the selection indicator is set to true or the reselection indicator is set to true in CBR range 1 and parameter PPPP1, the V2X terminal operates as follows. For example, in the case where the CBR measurement result is within CBR range 1 and the PPPP of the V2X data to be transmitted is 1, the V2X terminal may refer to the CBR range 1 and the value of the indicator (i.e., the selection indicator or the reselection indicator) of the PPPP1, and may perform a carrier selection or reselection operation if the indicator is set to true. For example, in the case where the CBR result measured by the V2X terminal is within CBR range 1 and the PPPP of the V2X data to be transmitted is 1, the V2X terminal may refer to the CBR range 1 and the value of the selection indicator of the PPPP1, and may not perform a carrier selection or reselection operation if the indicator is set to false.

[ Table 31]

Table 32 shows an example in which the selection indicator or reselection indicator is present in all CBR-PPPP ranges in the table. If the corresponding selection indicator or reselection indicator exists in all CBR-PPPP ranges, and if the indicator is set to the CBR-PPPP range, the selection indicator or reselection indicator may be used as a carrier reselection condition or a carrier reselection determination condition in the corresponding CBR-PPPP range. For example, if the selection indicator or reselection indicator is set to true under the conditions of CBR range 1 and parameter PPPP1, the V2X terminal operates as follows. For example, in the case where the CBR result measured by the V2X terminal is within CBR range 1 and the PPPP of the V2X data to be transmitted is 1, the V2X terminal may refer to the CBR range 1 and the value of the indicator (i.e., the selection indicator or the reselection indicator) of the PPPP1 and may perform a carrier selection or reselection operation if the indicator is set to true. For example, in the case where the CBR result measured by the V2X terminal is within CBR range 1 and the PPPP of the V2X data to be transmitted is 1, the V2X terminal may refer to the CBR range 1 and the value of the selection indicator or reselection indicator of the PPPP1, and may not perform a carrier selection or reselection operation if the indicator is set to false.

[ Table 32]

An example of RRC signaling including the information in tables 31 and 32 is as follows. As an embodiment of RRC asn.1, the selection indicator or reselection indicator may be included in the SL-CBR-PPPP-txcon-figlist shown in table 33. Table 33 shows an embodiment of the SL-CBR-PPPP-TxConfigList information component.

[ Table 33]

As an indicator indicating carrier selection, the selection indicator of Tx-ConfigList-r15 may be set to true or false. As an indicator indicating carrier reselection, the reselection indicator of Tx-ConfigList-r15 may be set to true or false. As an example of tables 31 and 32, the selection indicator or reselection indicator may be combined with a priority threshold (priority threshold) or a CBR configuration index (CBR-ConfigIndex), and then may be used as a carrier selection or reselection condition.

Further, the selection indicator or reselection indicator may be set to the same value or may have different values.

In case that the V2X terminal selects a carrier, the V2X terminal may select a candidate resource pool by referring to the selection indicator. In case that the V2X terminal reselects a carrier after selection of the carrier, the V2X terminal may select a candidate resource pool by referring to the reselection indicator.

Tables 34 through 36 according to various embodiments of the present disclosure illustrate another embodiment of RRC signaling in which CBR common TX configuration of system information is used.

Table 34 shows an example in which the selection indicator is present in only some CBRs in the CBR common TX configuration table. In case the selection indicator is set to a specific CBR index of the CBR common TX configuration, an operation of the same indicator (e.g., a carrier selection condition or a carrier reselection condition) may also be applied to a CBR index higher than the specific CBR index. For example, if the selection indicator of CBR index 2 is set to true, the V2X terminal may operate as follows. In case that the CBR index determined based on the CBR measurement result of the resource pool and the PPPP of the data to be transmitted is 3, if it is assumed that the CBR index 3 is higher than the reference CBR index 2 because the selection indicator of the CBR index 2 is set to true, the V2X terminal may perform a carrier selection or reselection operation by applying the fact that the selection indicator is true for the CBR index 3.

[ Table 34]

CBR index 1	CRLimit, Transmission parameter
		CBR index
2	CRLimit, Transmission parameter, selection indicator
		…	…
CBR index 16	CRLimit, Transmission parameter

Table 35 shows an example in which the selection indicator exists in all CBR indexes of the CBR common TX configuration. That is, the selection indicator set in each CBR index of the CBR common TX configuration may be used as a carrier selection or reselection condition. For example, if the selection indicator of CBR index 2 is set to true, the V2X terminal may operate as follows. If the V2X terminal determines CBR index 2 based on the CBR measurement result of the resource pool and the PPPP of the data to be transmitted, the V2X terminal may perform a carrier selection or reselection operation because the selection indicator of CBR index 2 is set to true. For example, in case that CBR index 2 is determined based on the CBR result measured by the V2X terminal and the PPPP of data to be transmitted, the V2X terminal may refer to the value of the selection indicator of CBR index 2 and may not perform a carrier selection or reselection operation if the indicator is set to false.

[ Table 35]

CBR index 1	CRLimit, Transmission parameter, selection indicator
		CBR index
2	CRLimit, Transmission parameter, selection indicator
		…	…
CBR index 16	…

An example of RRC signaling including the information in tables 34 and 35 described above is as follows. As an embodiment of RRC asn.1, the selection indicator may be included in, for example, SL-CBR-CommonTxConfigList shown in table 36 below. Table 36 shows an embodiment of the SL-CBR-CommonTxConfigList information component.

[ Table 36]

The selection indicator of SL-CBR-PSSCH-TxConfig-r15 may be set to true or false as an indicator indicating carrier selection or reselection. As in the embodiments of tables 34 and 35, the selection indicator may be combined with a CBR index, CR-Limit, Transmission (TX) parameter, priority threshold (priority threshold), etc., and then may be used as a carrier selection or reselection condition.

Tables 37 and 38 below illustrate other embodiments of RRC signaling in which CBR common TX configuration of system information is used, according to various embodiments of the present disclosure. The candidate resource pool may be selected using the selection indicator or reselection indicator in tables 37 and 38 below. When a V2X terminal selects a carrier, the selection indicator is used to determine the carriers available for the V2X terminal. When the V2X terminal uses the selected carrier, the reselection indicator is used to reselect the carrier.

Table 37 shows an example in which the selection indicator or reselection indicator is only present in a specific CBR index range of the CBR common TX configuration. If an indicator (e.g., a selection indicator or reselection indicator) is included in a specific index of the CBR common TX configuration in the table, an operation (e.g., carrier selection or reselection) of the same indicator may be performed for a CBR index higher than the specific index as a reference. For example, if the selection indicator or reselection indicator of CBR index 2 is set to true, the V2X terminal may operate as follows. The V2X terminal may determine the CBR index based on the CBR measurements of the resource pool and the PPPP of the data to be transmitted. If it is assumed that the CBR index 3 determined by the V2X terminal is higher than the reference CBR index 2 because the indicator (e.g., the selection indicator or the reselection indicator) of CBR index 2 is set to true, the V2X terminal may also perform a carrier selection or reselection operation by applying the indicator of CBR index 2 in case of CBR index 3.

[ Table 37]

Table 38 shows an example in which the selection indicator or reselection indicator is present in all CBR indices of the CBR common TX configuration. An indicator (e.g., a selection indicator or reselection indicator) set for a CBR index of the CBR common TX configuration may be used as a carrier selection or reselection condition. For example, if the selection indicator or reselection indicator of CBR index 2 is set to true, the V2X terminal may operate as follows. The V2X terminal may determine the CBR index based on the CBR measurements of the resource pool and the PPPP of the data to be transmitted. In case that the CBR index is determined to be 2 according to the determination of the V2X terminal, the V2X terminal may perform a carrier selection or reselection operation because an indicator (e.g., a selection indicator or a reselection indicator) of the CBR index is set to true. For example, in the case where an indicator (e.g., a selection indicator or a reselection indicator) of CBR index 2 is set to false, if the CBR index determined by the V2X terminal is 2, the V2X terminal may not perform a carrier selection or reselection operation.

[ Table 38]

As an example of RRC signaling in tables 37 and 38, the selection indicator or reselection indicator may be included in SL-CBR-CommonTxConfigList. Table 39 shows an example of asn.1 for RRC signaling. Table 39 illustrates an embodiment of the SL-CBR-CommonTxConfigList information component.

[ Table 39]

As an indicator indicating carrier selection, the selection indicator may be set to true or false. As an indicator indicating carrier reselection, the reselection indicator may be set to true or false. The selection indicator and the reselection indicator may be set to the same value or may have different values.

Tables 40 through 41 below illustrate embodiments of CBR common TX configurations in which system information is used, according to various embodiments of the present disclosure. The V2X terminal may use the TX parameters including the corresponding selection indicator or reselection indicator as carrier selection and reselection conditions. For example, if the selection indicator or reselection indicator is set to true in the TX parameter configuration, the V2X terminal may operate as follows. The V2X terminal may determine the CBR index based on the CBR measurements of the resource pool and the PPPP of the data to be transmitted. The V2X terminal may select the TX parameters based on the determined CBR index. If the indicator (i.e., the selection indicator or reselection indicator) is set to true in the TX parameters, the V2X terminal may perform a carrier selection or reselection operation. If the indicator (i.e., the selection indicator or reselection indicator) is set to false in the TX parameters, the V2X terminal may not perform carrier selection or reselection operations.

Tables 40 and 41 illustrate embodiments of RRC signaling where the TX parameters in SL-CBR-PPPP-txcon fig list include a selection indicator or reselection indicator. Tables 40 and 41 illustrate embodiments of the SL-CBR-CommonTxConfigList information component.

[ Table 40]

[ Table 41]

As an indicator indicating carrier selection, the selection indicator may be set to true or false. As an indicator indicating carrier reselection, the reselection indicator may be set to true or false.

Further, the selection indicator and the reselection indicator may be set to the same value or may have different values.

In case that the V2X terminal initially selects a carrier, the V2X terminal may select a candidate resource pool by considering the selection indicator. Further, the V2X terminal may select the candidate resource pool by reselecting the indicator after selection of the carrier.

The embodiments of tables 28 to 41 may be used alone or as a combination thereof. Examples using the embodiments of tables 28 to 41 as combinations thereof are as follows. The V2X terminal may use table 31 as the carrier selection criteria. First, the V2X terminal filters the carrier selection candidates that can be used for the conditions of table 31. Thereafter, the V2X terminal may filter it again according to the conditions of tables 40 and 41 to finally determine the available candidate carrier resources.

The selection indicator or reselection indicator in tables 28 to 41 in the above-described embodiments may be indicator information allocated to each carrier or indicator information common to all carriers.

The candidate resource pool may be selected in the MAC layer using events according to the embodiments of fig. 8, 10 to 12, 15, 16 and 19 or using tables 28 to 41. In this case, for the comparison group, according to various embodiments of the present disclosure, (i) a previous CBR value of the currently used carrier (e.g., a CBR result 100ms before the current time or a CBR value at a previous resource selection time) may be compared with a current CBR value of the currently used carrier (i.e., a CBR value at the current time or a CBR value at the current resource selection time) to determine carrier selection or reselection, or (ii) the current CBR value of the currently used carrier and the current CBR value of the candidate carrier may be used to determine carrier selection or reselection.

According to various embodiments of the present disclosure, a method for operating a terminal in a wireless communication system is provided. The method comprises the following steps: obtaining information about a first threshold and a second threshold of a Channel Busy Rate (CBR); measuring a first CBR of a first carrier configured by an upper layer and a plurality of second CBRs of a plurality of second carriers; and determining at least one transmission carrier from the first carrier and the plurality of second CBRs based on the first threshold, the second threshold, the first CBR, and the plurality of second CBRs. In some embodiments, wherein determining at least one transmission carrier comprises: the at least one transmission carrier is determined to be at least one of the plurality of second carriers having at least one lowest CBR if the first CBR is above a first threshold and the plurality of second CBRs are below a second threshold. In some embodiments, wherein determining at least one transmission carrier comprises: determining the at least one transmission carrier as the first carrier if the first CBR is below a first threshold or the plurality of second CBRs is above a second threshold. In some embodiments, wherein the information on the first threshold and the second threshold is acquired from an upper layer through Radio Resource Control (RRC) reconfiguration. In some embodiments, wherein the information on the first threshold and the second threshold is obtained from an upper layer through a system information block. In some embodiments, the method further comprises: available resources of at least one transmission carrier are sensed. In some embodiments, the method further comprises: transmitting a request for resource allocation using at least one transmission carrier; and receiving a resource allocation message of available resources of at least one transmission carrier. In some embodiments, the method further comprises: data is transmitted based on the available resources.

According to various embodiments of the present disclosure, a terminal in a wireless communication system is provided. The terminal includes a transceiver; and a processor operatively coupled to the transceiver and configured to: the method includes acquiring information on a first threshold and a second threshold of a Channel Busy Rate (CBR), measuring a first CBR of a first carrier configured by an upper layer and a plurality of second CBRs of a plurality of second carriers, and determining at least one transmission carrier from the first carrier and the plurality of second CBRs based on the first threshold, the second threshold, the first CBR, and the plurality of second CBRs. In some embodiments, wherein the processor is further configured to: the at least one transmission carrier is determined to be at least one of the plurality of second carriers having at least one lowest CBR if the first CBR is above a first threshold and the plurality of second CBRs are below a second threshold. In some embodiments, wherein the processor is further configured to: determining the at least one transmission carrier as the first carrier if the first CBR is below a first threshold or the plurality of second CBRs is above a second threshold. In some embodiments, wherein the information on the first threshold and the second threshold is acquired from an upper layer through Radio Resource Control (RRC) reconfiguration. In some embodiments, wherein the information on the first threshold and the second threshold is obtained from an upper layer through a system information block. In some embodiments, wherein the processor is further configured to sense available resources of the at least one transmission carrier. In some embodiments, wherein the processor is further configured to: the control transceiver sends a request for resource allocation using at least one transmission carrier and receives a resource allocation message of available resources of the at least one transmission carrier. In some embodiments, wherein the processor is further configured to control the transceiver to transmit data based on the sensed available resources.

According to various embodiments of the present disclosure, a method for operating a base station in a wireless communication system is provided. The method comprises the following steps: transmitting information on a first threshold value and a second threshold value of a channel busy rate to a terminal; receiving a request for resource allocation using at least one transmission carrier determined based on a first threshold, a second threshold, a first CBR of a first carrier, and a plurality of second CBRs of a plurality of second carriers; and transmitting a resource allocation message for available resources of at least one transmission carrier. In some embodiments, wherein the at least one transmission carrier is determined to be at least one of the plurality of second carriers having at least one lowest CBR if the first CBR is above a first threshold and the plurality of second CBRs are below a second threshold. In some embodiments, wherein the at least one transmission carrier is determined to be the first carrier if the first CBR is below a first threshold or the plurality of second CBRs is above a second threshold. In some embodiments, wherein the information regarding the first threshold and the second threshold is transmitted by a Radio Resource Control (RRC) reconfiguration or a system information block.

The method according to the embodiments set forth in the claims and/or the description of the present disclosure may be implemented in hardware, software, or a combination of hardware and software.

When the method is implemented by software, a computer-readable storage medium for storing one or more programs (software modules) may be provided. One or more programs stored in the computer-readable storage medium may be configured to be executed by one or more processors in the electronic device. The at least one program may include instructions that cause the electronic device to perform methods in accordance with various embodiments defined by the appended claims and/or the disclosure herein.

The program (software module or software) may be stored in non-volatile Memory including random access Memory and flash Memory, Read Only Memory (ROM), Electrically Erasable Programmable Read Only Memory (EEPROM), magnetic disk storage devices, optical disk ROM (CD-ROM), Digital Versatile Disks (DVD), or other types of optical storage devices or cartridges. Alternatively, any combination of some or all of them may form a memory in which the program is stored. Furthermore, a plurality of such memories may be included in an electronic device.

Further, the program may be stored in an attachable storage device accessible through a communication network such as the internet, an intranet, a Local Area Network (LAN), a Wide Area Network (WAN), and a Storage Area Network (SAN), or a combination thereof. Such a storage device may access the electronic device via an external port. In addition, a separate storage device on the communication network may access the portable electronic device.

In the above detailed embodiments of the present disclosure, components included in the present disclosure are expressed in the singular or plural according to the presented detailed embodiments. However, the singular or plural forms are chosen for ease of description as appropriate to the circumstances presented, and the various embodiments of the disclosure are not limited to a single element or multiple elements thereof. Further, a plurality of elements expressed in the specification may be configured as a single element, or a single element in the specification may be configured as a plurality of elements.

While the disclosure has been shown and described with reference to certain embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the disclosure. Therefore, the scope of the present disclosure should not be defined as limited to the embodiments, but should be defined by the appended claims and equivalents thereof.

While the present disclosure has been described with various embodiments, various changes and modifications may be suggested to one skilled in the art. The present disclosure is intended to embrace such alterations and modifications as fall within the scope of the appended claims.

Claims

1. A method for operating a terminal in a wireless communication system, the method comprising:

obtaining information about a first threshold and a second threshold of a channel busy rate CBR;

measuring a first CBR of a first carrier configured by an upper layer and a plurality of second CBRs of a plurality of second carriers;

determining at least one transmission carrier from the first carrier and the plurality of second CBRs based on the first threshold, the second threshold, the first CBR, and the plurality of second CBRs.

2. The method of claim 1, wherein the first and second light sources are selected from the group consisting of,

wherein determining the at least one transmission carrier comprises:

determining the at least one transmission carrier as at least one of the plurality of second carriers having at least one lowest CBR if the first CBR is above the first threshold and the plurality of second CBRs is below the second threshold.

3. The method of claim 1, wherein the first and second light sources are selected from the group consisting of,

wherein determining the at least one transmission carrier comprises:

determining the at least one transmission carrier as the first carrier if the first CBR is below the first threshold or the plurality of second CBRs is above the second threshold.

4. The method of claim 1, wherein the information on the first threshold and the second threshold is acquired from an upper layer through Radio Resource Control (RRC) reconfiguration or a system information block.

5. The method of claim 1, further comprising:

available resources of the at least one transmission carrier are sensed.

6. The method of claim 1, further comprising:

transmitting a request for resource allocation using the at least one transmission carrier; and

receiving a resource allocation message of available resources of the at least one transmission carrier.

7. The method of claim 5 or 6, further comprising:

and transmitting data based on the available resources.

8. A terminal in a wireless communication system, the terminal comprising:

a transceiver; and

a processor operatively coupled to the transceiver and configured to:

acquiring information on a first threshold value and a second threshold value of a channel busy rate CBR,

measuring a first CBR of a first carrier configured by an upper layer and a plurality of second CBRs of a plurality of second carriers,

9. The terminal according to claim 8, wherein,

wherein the processor is further configured to:

10. The terminal according to claim 8, wherein,

wherein the processor is further configured to:

11. The terminal of claim 8, wherein the information on the first and second thresholds is acquired from an upper layer through Radio Resource Control (RRC) reconfiguration or a system information block.

12. The terminal of claim 8, wherein the processor is further configured to sense available resources of the at least one transmission carrier.

13. The terminal according to claim 8, wherein,

wherein the processor is further configured to:

control the transceiver to send a request for resource allocation using the at least one transmission carrier, an

Control the transceiver to receive a resource allocation message of available resources of the at least one transmission carrier.

14. A terminal as claimed in claim 12 or 13, wherein the processor is further configured to control the transceiver to transmit data based on the sensed available resources.

15. A method for operating a base station in a wireless communication system, the method comprising:

transmitting information on a first threshold value and a second threshold value of a channel busy rate CBR to a terminal;

receiving a request for resource allocation using at least one transmission carrier determined based on the first threshold, the second threshold, a first CBR of a first carrier and a plurality of second CBRs of a plurality of second carriers; and

transmitting a resource allocation message for available resources of the at least one transmission carrier.