Wireless Terminal and Its Method

Abstract

A wireless terminal (1A) generates a buffer state report or traffic pattern information in consideration of the transmission situation of transmission on a second sidelink carrier. The wireless terminal (1A) transmits the generated buffer state report or traffic pattern information to a wireless access network node (2). This can contribute, for example, to, when a first sidelink carrier, to which a first resource assignment mode is applied in which a resource is assigned by the wireless access network node, is aggregated with a second sidelink carrier, to which a second resource assignment mode is applied in which the wireless terminal autonomously selects a resource, avoiding the wireless terminal obtaining an excessive grant exceeding an amount actually required for transmission on the first sidelink carrier.

Description

Technical Field

[0001] The present disclosure relates to direct communication between wireless terminals (device-to-device (D2D) communication), and more particularly to the use of multiple carriers in direct communication.

Background Art

[0002] A form in which a wireless terminal directly communicates with another wireless terminal without going through an infrastructure network such as a base station is generally called device-to-device (D2D) communication. D2D communication can be integrated with or supported by a cellular network. Proximity-based services (ProSe) defined in Third Generation Partnership Project (3GPP (registered trademark)) Release 12 and later provide a system architecture for D2D communication supported by a cellular network. In addition, the cellular Vehicle-to-Everything (V2X) service defined since 3GPP Release 14 refers to ProSe and uses D2D communication between wireless terminals. D2D communication supported by a cellular network can also be used for other applications and services (e.g., public safety applications) other than V2X services.

[0003] The interface between 3GPP radio terminals (i.e., User Equipments (UEs)) used for the control plane and user plane of D2D communication is called the PC5 interface (or reference point). D2D communication on the PC5 interface is called sidelink communication. The PC5 interface can be based on the Evolved Universal Terrestrial Radio Access (E-UTRA) sidelink capabilities and can further be based on the 5G New Radio (NR) sidelink capabilities. D2D communication (or sidelink communication) on the E-UTRA-PC5 (or Long Term Evolution (LTE) based PC5) interface is connectionless, i.e., in broadcast mode in the Access Stratum (AS) layer. In contrast, sidelink communication on the NR PC5 interface supports unicast mode, groupcast mode, and broadcast mode in the AS layer.

[0004] Side-link communication on the E-UTRA-PC5 interface is, for example, called LTE side-link communication. Side-link communication on the NR PC5 interface is, for example, called NR side-link communication. The 3GPP specifications define enhancements to the architecture to facilitate vehicular communications for cellular V2X services (see, for example, Non-Patent Documents 1, 2, and 3). LTE side-link communication and NR side-link communication play important roles in the realization of cellular V2X communication. The AS functionality using E-UTRA technology including LTE side-link communication to enable V2X communication between UEs, or V2X communication on the E-UTRA-PC5 interface, is called V2X side-link communication or LTE V2X side-link communication. The AS functionality using NR technology including NR side-link communication to enable V2X communication between UEs, or V2X communication on the NR PC5 interface, is called NR V2X side-link communication or simply NR side-link communication.

[0005] 3GPP Release 15 supports carrier aggregation (CA) and multi-carrier operation for LTE side-link communication (see Non-Patent Documents 1 and 4). For 3GPP Release 18, 3GPP plans to discuss Sidelink Evolution. This includes support for carrier aggregation for NR side-link communication and support for side-link on unlicensed spectrum (see Non-Patent Document 5).

[0006] Patent Documents 1, 2, and 3 disclose sidelink (SL) carrier aggregation, that is, carrier aggregation for SL communication, and in particular disclose the signaling between UEs and between a UE and a radio access network (e.g., a base station) regarding SL carrier aggregation.

[0007] Patent Document 1 describes that the UE may send SL carrier aggregation settings related to the addition, release, and modification of secondary SLs to a peer UE (see, for example, FIGS. 3, 4, 5, and 10 of Patent Document 1). The SL carrier aggregation settings may be related to the addition, release, and modification of secondary SLs and may include carrier frequency settings and deactivation timer information. The SL carrier aggregation settings may include Rx or Tx indication, primary SL or secondary SL indication, type of carrier aggregation (e.g., data replication or data splitting), V2X service type, synchronization type, index of the primary SL (carrier index), index of the secondary SL (carrier index), resource allocation information for SL transmission or reception, etc.

[0008] Patent Document 1 describes that after PC5 carrier aggregation is set, the UE may notify the base station of this (see, for example, FIG. 6 of Patent Document 1). The notification message may include at least one of a set of carrier frequency information, a deactivation timer, and a peer UE identifier. For each SL component carrier, the notification message may further include Rx or Tx indication, primary SL or secondary SL indication, type of carrier aggregation (e.g., data replication or data splitting), V2X service type, synchronization type, index of the primary SL (carrier index), index of the secondary SL (carrier index), resource allocation information for SL transmission or reception, etc.

[0009] Patent Document 1 describes that a UE may send a request for SL carrier aggregation configuration between the UE and a peer UE to the base station, or the base station may generate the configuration and provide it to the UE (see, for example, FIG. 9 of Patent Document 1). Further, Patent Document 1 describes that the request message is optional, and the base station may provide the SL carrier aggregation configuration to the UE regardless of receiving a request message from the UE.

[0010] Patent Document 1 describes that before setting SL carrier aggregation, UEs may directly exchange information regarding their respective SL carrier aggregation capabilities with each other (see, for example, FIG. 13 of Patent Document 1). The SL carrier aggregation capability includes one or both of SL band combination information and SL band and Uu band combination information. Uu is the air interface between the UE and the base station. The UE's band combination information indicates a list of carriers that the UE can operate simultaneously and the bandwidth of each carrier. The UE may indicate whether it supports both transmission (Tx) and reception (Rx) on each carrier, or only one of transmission (Tx) and reception (Rx).

[0011] Patent Document 2 describes that a UE receives a Radio Resource Control (RRC) signal (e.g., RRC Connection Reconfiguration message) including an additional or release command for a component carrier of V2X carrier aggregation from a wireless wide area network (WAN) (see, for example, FIGS. 2 and 3 of Patent Document 2).

[0012] Patent Document 3 describes that a first wireless terminal receives a sidelink message including sidelink capability information of a second wireless terminal from the second wireless terminal via a sidelink channel, and transmits an uplink message including the sidelink capability information to a base station (see, for example, FIG. 25 of Patent Document 3). The sidelink capability information of the second wireless terminal may indicate whether the second wireless terminal supports sidelink multiple carrier operations (e.g., sidelink carrier aggregation, sidelink multiple carriers, sidelink multi-carrier), the sidelink it supports / operates on (e.g., LTE, 5G, etc.), available bands, whether the second wireless terminal supports an unlicensed band (or unlicensed spectrum), and so on. The base station may determine setting parameters for sidelink communication between the first and second wireless terminals based on the sidelink capability information of the second wireless terminal, and send the setting parameters to the first wireless terminal. The setting parameters may be transmitted in an RRC message, a Medium Access Control (MAC) Control Element (CE), or a Physical Downlink Control Channel (PDCCH) transmission (e.g., Downlink Control Information (DCI)).

[0013] Patent Document 3 describes that a first wireless terminal receives from a second wireless terminal, via a sidelink channel, a sidelink message including the band combination information of the second wireless terminal, and transmits an uplink message (e.g., an RRC message) including the band combination information to a base station (see, for example, FIG. 26 of Patent Document 3). The band combination information of the second wireless terminal may indicate one or more bands that are permitted to be used simultaneously for sidelink communication in the second wireless terminal. The band combination information of the second wireless terminal may indicate whether the second wireless terminal supports a plurality of (multiple) sidelink carriers (e.g., multi-carrier operation, sidelink carrier aggregation). For example, when the band combination information indicates that the second wireless terminal supports a plurality of sidelink carriers, the base station may determine or assign resources corresponding to the plurality of carriers. The base station sends to the first wireless terminal setting parameters for sidelink communication between the first and second wireless terminals. The setting parameters may indicate a sidelink resource assignment. More specifically, the wireless resource assignment may indicate a first sidelink wireless resource of a first carrier and a second sidelink wireless resource of a second carrier. The first wireless terminal may transmit a first transport block to the second wireless terminal via the first sidelink wireless resource and transmit a second transport block to the second wireless terminal via the second sidelink wireless resource.

Prior Art Documents

Patent Documents

[0014]

Patent Document 1

Patent Document 2

Patent Document 3

Non-Patent Document

[0015]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Non-Patent Document 4

Non-Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0016] The inventor has considered carrier aggregation for D2D communication including NR sidelink communication and found various problems. Carrier aggregation on the D2D interface or sidelink interface (e.g., PC5 interface) between wireless terminals can also be called multi-carrier operation.

[0017] One of these problems relates to how to support cases where different resource allocation modes are applied among a plurality of sidelink carriers to be aggregated. NR sidelink communication supports two resource allocation modes, namely mode 1 and mode 2. In resource allocation mode 1, the radio access network (e.g., gNB) performs resource allocation. In contrast, in resource allocation mode 2, the UE autonomously selects resources from the resource pool based on sensing by the UE. The carrier aggregation of LTE sidelink communication defined in 3GPP Release 15 does not stipulate such a mixture of resource allocation modes. The above non-patent documents and patent documents do not provide solutions regarding such a mixture of resource allocation modes.

[0018] Another one of these problems relates to how a UE coordinates or prioritizes between transmissions on carriers to which resource allocation mode 1 is applied and transmissions on carriers to which resource allocation mode 2 is applied. The above-mentioned non-patent documents and patent documents do not provide a solution to this problem.

[0019] One of the objects to be achieved by the embodiments disclosed in this specification is to provide an apparatus, a method, and a program that contribute to solving at least one of a plurality of problems including the above-mentioned problems related to carrier aggregation in a D2D interface between wireless terminals. It should be noted that this object is only one of the plurality of objects to be achieved by the plurality of embodiments disclosed in this specification. Other objects or problems and novel features will be apparent from the description of this specification or the accompanying drawings.

Means for Solving the Problems

[0020] In a first aspect, a wireless terminal includes at least one wireless transceiver and at least one processor coupled to the at least one wireless transceiver. The at least one processor is configured to use, for sidelink communication with a peer wireless terminal, a first sidelink carrier to which a first resource allocation mode in which resources are allocated by a radio access network node is applied and a second sidelink carrier to which a second resource allocation mode in which the wireless terminal autonomously selects resources is applied. The at least one processor is configured to generate one or both of a buffer status report and traffic pattern information in consideration of a transmission status of a transmission on the second sidelink carrier. The at least one processor is configured to transmit one or both of the buffer status report and the traffic pattern information to the radio access network node.

[0021] In a second aspect, a method performed by a wireless terminal includes the following steps: (a) Use a first sidelink carrier to which a first resource allocation mode in which resources are allocated by a radio access network node is applied and a second sidelink carrier to which a second resource allocation mode in which the wireless terminal autonomously selects resources is applied for sidelink communication with a peer wireless terminal, (b) Generate one or both of a buffer status report and traffic pattern information in consideration of a transmission status of transmission on the second sidelink carrier, (c) Transmit one or both of the buffer status report and the traffic pattern information to the radio access network node.

[0022] In a third aspect, a wireless terminal includes at least one radio transceiver and at least one processor coupled to the at least one radio transceiver. The at least one processor is configured to use a first sidelink carrier to which a first resource allocation mode in which resources are allocated by a radio access network node is applied and a second sidelink carrier to which a second resource allocation mode in which the wireless terminal autonomously selects resources is applied for sidelink communication with a peer wireless terminal. The at least one processor is configured to transmit to the radio access network node one or both of a buffer status report for obtaining a dynamic grant of the first sidelink carrier and traffic pattern information for obtaining a configured grant of the first sidelink carrier. The at least one processor is configured to transmit to the radio access network node assistance information used by the radio access network node to estimate a transmission status of transmission on the second sidelink carrier.

[0023] In a fourth aspect, a method performed by a wireless terminal includes the following steps: (a) A first sidelink carrier to which a first resource allocation mode in which resources are allocated by a radio access network node is applied and a second sidelink carrier to which a second resource allocation mode in which the wireless terminal autonomously selects resources is applied are used for sidelink communication with a peer wireless terminal, (b) Transmit one or both of a buffer status report for obtaining a dynamic grant of the first sidelink carrier and traffic pattern information for obtaining a configured grant of the first sidelink carrier to the radio access network node, (c) Transmit assistance information used by the radio access network node to estimate the transmission status of transmissions on the second sidelink carrier to the radio access network node.

[0024] In a fifth aspect, a radio access network node includes at least one memory and at least one processor coupled to the at least one memory. The at least one processor is configured to receive from a wireless terminal one or both of a buffer status report for obtaining a dynamic grant of a first sidelink carrier to which a first resource allocation mode in which resources are allocated by the radio access network node is applied and traffic pattern information for obtaining a configured grant of the first sidelink carrier. The at least one processor is configured to receive from the wireless terminal assistance information regarding a second sidelink carrier to which a second resource allocation mode in which the wireless terminal autonomously selects resources is applied. The at least one processor is configured to generate one or both of a dynamic grant and a configured grant in consideration of the transmission status of transmissions on the second sidelink carrier obtained based on the assistance information. The at least one processor is configured to transmit one or both of the generated dynamic grant and the generated configured grant to the wireless terminal.

[0025] In a sixth aspect, the method performed by a radio access network node includes the following steps: (a) Receive, from a wireless terminal, one or both of a buffer status report for obtaining a dynamic grant of a first sidelink carrier to which a first resource allocation mode in which resources are allocated by the radio access network node is applied, and traffic pattern information for obtaining a configured grant of the first sidelink carrier, (b) Receive, from the wireless terminal, assistance information regarding a second sidelink carrier to which a second resource allocation mode in which the wireless terminal autonomously selects resources is applied, (c) Generate one or both of a dynamic grant and a configured grant in consideration of a transmission status of transmission on the second sidelink carrier obtained based on the assistance information, (d) Transmit one or both of the generated dynamic grant and the generated configured grant to the wireless terminal.

[0026] In a seventh aspect, a wireless terminal includes at least one radio transceiver and at least one processor coupled to the at least one radio transceiver. The at least one processor is configured to use, for sidelink communication with a peer wireless terminal, a first sidelink carrier to which a first resource allocation mode in which resources are allocated by a radio access network node is applied and a second sidelink carrier to which a second resource allocation mode in which the wireless terminal autonomously selects resources is applied. The at least one processor is configured to determine, according to a predetermined rule, on which of the first sidelink carrier and the second sidelink carrier to transmit the data when resources of the second sidelink carrier are also available in a time slot of the first sidelink carrier in which there is data to be transmitted and a dynamic grant or a configured grant has been obtained.

[0027] In an eighth aspect, the method performed by a wireless terminal includes the following steps: (a) A first sidelink carrier to which a first resource allocation mode in which resources are allocated by a radio access network node is applied and a second sidelink carrier to which a second resource allocation mode in which the wireless terminal autonomously selects resources is applied are used for sidelink communication with a peer wireless terminal. (b) When there is data to be transmitted and resources of the second sidelink carrier are also available in a time slot of the first sidelink carrier for which a dynamic grant or a configured grant has been obtained, it is determined which of the first sidelink carrier and the second sidelink carrier to transmit the data according to a predetermined rule.

[0028] In a ninth aspect, the program includes an instruction group (software code) for causing a computer to perform the method according to the second, fourth, sixth, or eighth aspect described above when loaded into the computer.

Advantages of the Invention

[0029] According to the above aspect, an apparatus, a method, and a program can be provided that contribute to solving at least one of a plurality of problems related to carrier aggregation at a D2D interface between wireless terminals.

Brief Description of the Drawings

[0030]

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DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, specific embodiments will be described in detail with reference to the drawings. In each drawing, the same or corresponding elements are denoted by the same reference numerals, and redundant descriptions may be omitted as necessary for clarity of explanation.

[0032] The following multiple embodiments can be implemented independently or in appropriate combination. These multiple embodiments have different novel features. Therefore, these multiple embodiments contribute to solving different objectives or problems and achieving different effects.

[0033] The following multiple embodiments are mainly described with respect to the 3GPP 5th generation mobile communication system (5G system). However, these embodiments may also be applied to other wireless communication systems that support D2D communication technologies similar to 3GPP's NR sidelink communication.

[0034] As used herein, depending on the context, "(if)~then" may be interpreted to mean "when", "at or around the time", "after", "upon", "in response to determining", "in accordance with a determination", or "in response to detecting". These expressions may be interpreted to have the same meaning depending on the context.

[0035] First, the configuration and operation of a plurality of network elements common to the multiple embodiments are described. FIG. 1 shows a configuration example of a wireless communication system according to the multiple embodiments. Each element (network function) shown in FIG. 1 can be implemented, for example, as a network element on dedicated hardware, as a software instance running on dedicated hardware, or as a virtualized function instantiated on an application platform.

[0036] A Radio Access Network (RAN) node (e.g., gNB) 2 manages cell 21 and can perform cellular communication (101 and 102) with a plurality of wireless terminals (UEs) 1 including UE1A and UE1B using cellular communication technology (i.e., NR Radio Access Technology). Cellular communication 101 uses an air interface (e.g., Uu interface) between RAN node 2 and UE1A. Similarly, cellular communication 102 uses an air interface (e.g., Uu interface) between RAN node 2 and UE1B. In the example of FIG. 1, for simplicity of explanation, a situation where UE1A and 1B are located within the same cell 21 is shown, but such an arrangement is merely an example. For example, UE1A may be located within one of two adjacent cells managed by different RAN nodes 2, and UE1B may be located within the other cell. Alternatively, at least one of UE1A and UE1B may be located outside the coverage by one or more RAN nodes 2 (i.e., partial coverage, out-of-coverage).

[0037] Each of UE1A and UE1B has at least one wireless transceiver, is configured to perform cellular communication (101 or 102) with RAN node 2, and to perform D2D communication (i.e., sidelink communication) on a UE - to - UE direct interface (i.e., NR PC5 interface or NR sidelink) 103. The sidelink communication includes unicast - mode communication (sidelink - unicast) and may further include one or both of group - cast - mode communication and broadcast - mode communication.

[0038] The interface between 3GPP wireless terminals (i.e., UEs) used for the control plane and user plane for D2D communication is called the PC5 interface (or reference point). D2D communication over the PC5 interface is called sidelink communication. The PC5 interface can be based on E-UTRA sidelink capabilities and can further be based on 5G NR sidelink capabilities. D2D communication (or sidelink communication) over the E-UTRA-PC5 (or LTE-based PC5) interface is connectionless, i.e., in broadcast mode at the AS layer. In contrast, sidelink communication over the NR PC5 interface supports unicast mode, groupcast mode, and broadcast mode at the AS layer.

[0039] In some implementations, sidelink communication between UE1A and UE1B may be used for cellular V2X services and V2X communication. In other words, UEs1A and 1B and RAN node 2 shown in FIG. 1 may be used in a 5G system that provides V2X communication over PC5. FIG. 2 shows an example of a non-roaming 5G system architecture for V2X communication over PC5. Each element (network function) shown in FIG. 2 can be implemented, for example, as a network element on dedicated hardware, as a software instance running on dedicated hardware, or as a virtualized function instantiated on an application platform. The main reference points (or interfaces) shown in FIG. 2 are described below.

[0040] In the following description, when describing matters common to a plurality of UEs including UE1A and 1B, UE1 is simply referred to using the reference numeral 1.

[0041] The V1 reference point is a reference point between the V2X application (e.g., V2X application 11A or V2X application 11B) within the UE1 (e.g., UE1A or UE1B) and the V2X application within the V2X application server 61. The V2X application server 61 is disposed in the data network (DN) 50.

[0042] The V5 reference point is a reference point between the V2X applications of two UEs1 (e.g., UE1A and UE1B). The PC5 reference point is a reference point between UEs (e.g., UE1A and UE1B) and includes NR based PC5. The Uu reference point is a reference point between the UE (e.g., UE1A) and the NG-RAN 20. Although not illustrated in FIG. 2, as already described, UE1B may also communicate with the NG-RAN 20 via the Uu reference point.

[0043] The N1 reference point is a reference point between UE1 (e.g., UE1A) and the Access and Mobility management Function (AMF) 41 within the 5G Core Network (5GC) 40. The N1 reference point may be used to send V2X policies and parameters from the AMF 41 to UE1, and to send the V2X capability and PC5 capability of UE1 for V2X communication from UE1 to the AMF 41. The N2 reference point is a reference point between the NG-RAN 20 and the AMF 41. The N2 reference point may be used to send V2X policies and parameters from the AMF 41 to the NG-RAN 20. The AMF 41 is one of the network function nodes within the control plane of the 5GC 40. The AMF 41 terminates one (single) signalling connection (i.e., N1 NAS signalling connection) with UE1 (e.g., UE1A) and provides registration management, connection management, and mobility management. The AMF 41 provides network function (NF) services to NF consumers (e.g., Session Management Function (SMF) 42) on a service-based interface (i.e., Namf interface). The NF services provided by the AMF 41 include the communication service (Namf_Communication). The communication service enables an NF consumer (e.g., SMF 42) to communicate with UE1 or the NG-RAN 20 via the AMF 41.

[0044] The N3 reference point is the reference point between the NG-RAN 20 and the User Plane Function (UPF) 43 within the 5GC. The N6 reference point is the reference point between the UPF 43 and the DN 50. The UPF 43 is one of the network function nodes within the user plane of the 5GC 40. The UPF 43 processes and forwards user data. The functionality of the UPF 43 is controlled by the SMF 42 via the N4 reference point. The UPF 43 may include a plurality of UPFs interconnected via the N9 reference point. For example, in order to enable the V2X application 11B within the UE 1A to communicate with the V2X application within the V2X application server 61, the UE 1A uses a path, association, session, or connection via the Uu reference point, the N3 reference point, and the N6 reference point.

[0045] The 5G system of FIG. 2 may provide a Network Exposure Function (NEF) service to enable communication between one or more network functions within 5GC 40 and the V2X application server 61. The NEF 46 is one of the network function nodes within the control plane of 5GC 40. The NEF 46 supports the exposure of services and capabilities from the 5G system to application functions and network functions inside and outside the operator network. The N33 reference point is the reference point between the NEF 46 and the application function (e.g., the V2X application server 61). The NEF 46 provides NF services to NF consumers (e.g., the V2X application server 61) on a service-based interface (i.e., the Nnef interface). In the case of the V2X service, the service provided by the NEF 46 may be used by the V2X application server 61 to update the V2X service-related information of 5GC 40. The NEF 46 may store the V2X service-related information in the Unified Data Repository (UDR) 45 directly via the N37 reference point or via the Policy Control Function (PCF) 44.

[0046] Figures 3, 4, and 5 show the AS protocol stacks of the PC5 interface 103. As shown in Figure 3, the control plane Access Stratum (AS) protocol stack for the Sidelink Control Channel (SCCH) for Radio Resource Control (RRC) (i.e., PC5-RRC) includes the RRC, Packet Data Convergence Protocol (PDCP), Radio Link Control (RLC), and Medium Access Control (MAC) sublayers as well as the Physical (PHY) layer. The SCCH is a sidelink logical channel for transmitting control information (i.e., PC5-RRC and PC5-S messages) from a UE (e.g., UE1A) to other UEs 1 (e.g., UE1B).

[0047] The PC5 interface 103 supports the PC5 Signalling (PC5-S) protocol. As shown in FIG. 4, in the control plane AS protocol stack for the SCCH for PC5-S, PC5-S is located on top of the PDCP, RLC, and MAC sublayers as well as the physical layer. PC5-S is used for control plane signalling on the PC5 interface 103 for a secure unicast layer 2 link (or PC5 unicast link). Specifically, PC5-S provides signalling for establishing, modifying, and releasing the PC5 unicast link. The PC5 unicast link between UE1A and UE1B is associated with the Application Layer ID and Layer-2 ID of UE1A and the Application Layer ID and Layer-2 ID of UE1B. The PC5 unicast link is bi-directional. Therefore, UE1A can transmit application data (e.g., V2X service data, public safety service data) to UE1B over the PC5 unicast link with UE1B, and UE1B can also transmit application data to UE1A over the said PC5 unicast link.

[0048] There is a one-to-one correspondence between a PC5 unicast link and a PC5-RRC connection. The PC5-RRC connection is a logical connection between two UEs1 for a pair of Source Layer-2 ID and Destination Layer-2 ID. The PC5-RRC connection is considered to be established after the corresponding PC5 unicast link is established. In other words, the PC5-RRC connection is established in response to the establishment of the corresponding PC5 unicast link. Specifically, if the transmission of a PC5-S message to a specific destination is requested by upper layers of the sidelink signalling radio bearer (SL SRB), UE1 (RRC layer) establishes a PDCP entity, an RLC entity, and an SCCH of the SL SRB for the PC5-S message based on a predefined SCCH configuration, and considers that the PC5-RRC connection to the destination is established. Alternatively, if the establishment of a PC5-RRC connection for a specific destination is indicated by upper layers, UE1 (RRC layer) establishes a PDCP entity, an RLC entity, and an SCCH of the SL SRB for the PC5-RRC message of the destination based on a predefined SCCH configuration, and considers that the PC5-RRC connection is established.

[0049] Figure 5 shows the AS user plane protocol stack for the Sidelink Traffic Channel (STCH). The STCH is a sidelink logical channel for transmitting user data (e.g., V2X service data, public safety service data) from UE1 (e.g., UE1A) to other UE(s) 1 (e.g., UE1B). The protocol stack includes the Service Data Adaptation Protocol (SDAP), PDCP, RLC, and MAC sublayers as well as the physical layer.

[0050] NR side link communication over the NR PC5 interface 103 supports two resource allocation modes, namely mode 1 and mode 2.

[0051] In resource allocation mode 1, the RAN node 2 (e.g., gNB) performs resource allocation. For example, the RAN node 2 allocates or schedules SL radio resources to UE1 using the NR Uu interface 101. Resource allocation by mode 1 includes dynamic grant and configured grant.

[0052] In the case of a dynamic grant, UE1 needs to request resources from RAN Node 2 for the transmission of every single transport block. More specifically, UE1 transmits a MAC Control Element (CE) indicating a Sidelink Buffer Status Report (BSR) (i.e., Sidelink BSR MAC CE) to RAN Node 2 via the Uplink Shared Channel (UL-SCH) and the Physical Uplink Shared Channel (PUSCH), and RAN Node 2 transmits Downlink Control Information (DCI) indicating a dynamic sidelink grant to UE1 via the Physical Downlink Control Channel (PDCCH). The dynamic sidelink grant provides resource allocation for the transmission (and retransmission) of every single transport block. Note that when sidelink carrier aggregation described later is configured, the dynamic sidelink grant may provide resource allocation for one transport block per sidelink (component) carrier.

[0053] In the case of a configured grant, RAN Node 2 permits UE1 to use periodic sidelink resources semi-statically configured by RRC. More specifically, UE1 can send UE assistance information regarding the traffic pattern of sidelink communication to RAN Node 2. Such UE assistance information, or the sidelink traffic pattern information sent with the UE assistance information, may be referred to as configured grant assistance information. The sidelink traffic pattern information (or configured grant assistance information) may indicate, for example, the maximum transport block size based on the observed traffic pattern, the estimated timing of packet arrival in the sidelink logical channel, and the estimated data arrival period in the sidelink logical channel. UE1 sends UE assistance information including the sidelink traffic pattern information using an RRC message (e.g., UEassistanceinformation message). RAN Node 2 may generate a configured grant considering the sidelink traffic pattern information received from UE1. RAN Node 2 sends the configured grant to UE1 using an RRC message (e.g., RRCReconfiguration message). The configured grant indicates the allocation of time and frequency resources and the period of the resource allocation. There are two types of configured grants for Mode 1. In the case of Configured Grant Type 1, the configured grant is set or released to UE1 by RRC signaling or a message (e.g., RRCReconfiguration message) and can be used immediately. In the case of Configured Grant Type 2, RAN Node 2 sets the configured grant to UE1 via RRC signaling or a message (e.g., RRCReconfiguration message) and activates or deactivates the configured grant via DCI signaling.UE1 can use the periodic resources allocated by the configured grant only after they are activated by RAN Node 2 and can use them until they are deactivated.

[0054] On the other hand, in resource allocation mode 2, UE1 autonomously selects resources based on sensing by UE1. The sensing is performed in a pre-configured resource pool. UE1 can select these resources for sidelink transmission and retransmission if the resources are not being used by other UEs for high-priority traffic. UE1 can perform a certain number of transmissions and retransmissions on the selected resources until the cause for resource reselection is triggered.

[0055] UE1A and UE1B support carrier aggregation (CA) on the NR PC5 interface (or NR sidelink) 103. In other words, UE1A and UE1B support NR sidelink carrier aggregation, i.e., carrier aggregation for NR sidelink communication. Sidelink carrier aggregation can also be referred to as multi-carrier operation. Sidelink carrier aggregation enables UE1A and UE1B to communicate with each other over multiple sidelink carriers. Similar to the terminology used for the Uu interface, the multiple sidelink carriers used in sidelink carrier aggregation may be referred to as component carriers. In one example, one or more of the multiple sidelink carriers may belong to a licensed spectrum (licensed band) licensed to RAN Node 2 (or NG-RAN 20) or its operator, and the other one or more may belong to unlicensed spectrum. The unlicensed spectrum may be ITS spectrum for intelligent transportation systems (ITS).

[0056] UE1A and UE1B support side - link carrier aggregation in unicast transmission. UE1A and UE1B may support side - link carrier aggregation in group - cast transmission. UE1A and UE1B may support side - link carrier aggregation in broadcast transmission.

[0057] In side - link carrier aggregation, one or both of UE1A and UE1B do not necessarily have to be unable to transmit simultaneously on multiple side - link carriers. In other words, one or both of UE1A and UE1B do not have to support transmission within the same time slot on multiple side - link carriers. A UE with such a restricted transmission function may be called a limited Tx capability UE. For example, the limited Tx capability may be due to the number of transmission chains of UE1 being smaller than the number of configured transmission side - link carriers. Alternatively, the limited Tx capability may be due to UE1 not supporting the band combination of the configured transmission side - link carriers. Alternatively, the limited Tx capability may be due to the time required for switching the transmission chains of UE1. Alternatively, the limited Tx capability may be due to UE1 being unable to meet the Radio Frequency (RF) requirements due to, for example, an imbalance in power spectral density (PSD).

[0058] Similarly, in side - link carrier aggregation, one or both of UE1A and UE1B do not necessarily have to be unable to receive simultaneously on multiple side - link carriers. In other words, one or both of UE1A and UE1B do not have to support reception within the same time slot on multiple side - link carriers. A UE1 with such a restricted reception function may be called a limited Rx capability UE.

[0059] FIG. 6 shows an example of the structure of NR sidelink layers 2 and 1 with carrier aggregation configured. The sidelink layer 2 includes a MAC sublayer 601, an RLC sublayer 602, a PDCP sublayer 603, and an SDAP sublayer 604. Basically, sidelink carrier aggregation is a concept of the MAC sublayer 601 and the physical layer 620, and is not applied to layers above the RLC sublayer 602. However, as will be described later, a PC5-RRC message regarding sidelink carrier aggregation may be introduced.

[0060] The physical layer 620 supports a plurality of sidelink carriers. If the UE supports transmission within the same time slot on a plurality of sidelink carriers, the physical layer 620 can transmit one transport block (or MAC Protocol Data Unit (PDU)) on each sidelink carrier in one time slot. The physical layer 620 offers transport channels to the MAC sublayer 601.

[0061] The MAC sublayer 601 provides one MAC entity for transmission and reception on a plurality of sidelink carriers. The MAC entity provides a hybrid automatic repeat request (HARQ) entity for each sidelink carrier. One HARQ entity maintains a plurality of HARQ processes, thereby enabling continuous transmission on the sidelink carrier corresponding to the HARQ feedback regarding the success or failure of the previous transmission while waiting for the HARQ feedback.

[0062] The MAC sublayer 601 provides logical channels to the RLC sublayer 602. The MAC sublayer 601 provides a mapping between logical channels and transport channels, and multiplexes MAC Service Data Units (SDUs) belonging to one or different logical channels. The transport channels used in the NR side link include the Sidelink Shared Channel (SL-SCH) and the Sidelink Broadcast Channel (SL-BCH). The logical channels used in the NR side link include the Sidelink Control Channel (SCCH), the Sidelink Traffic Channel (STCH), and the Sidelink Broadcast Control Channel (SBCCH). The SCCH is a control channel and is mapped to the SL-SCH. The STCH is a traffic channel and is mapped to the SL-SCH in the same way as the SCCH. The SBCCH is a control channel and is mapped to the SL-BCH.

[0063] The MAC sublayer 601 provides scheduling for the NR side link. The scheduling includes priority handling among multiple logical channels by logical channel prioritization.

[0064] If the UE supports transmission within the same time slot on multiple sidelink carriers and has grants on each of the multiple sidelink carriers, the MAC sublayer provides multiple transport blocks (MAC PDUs) to the physical layer 620 via multiple transport channels (i.e., SL-SCH) associated with each of the multiple sidelink carriers for transmission on the multiple sidelink carriers in the same time slot. Each grant may be a dynamic or configured grant in resource allocation mode 1. Alternatively, if the sidelink resource allocation mode 2 is set for the MAC entity to transmit using a resource pool, the MAC entity may generate a sidelink grant selected based on random selection or sensing in the resource pool.

[0065] The RLC sublayer 602 provides RLC channels to the PDCP sublayer 603. The RLC sublayer 602 supports three transmission modes, Acknowledged Mode (AM), Unacknowledged Mode (UM), and Transparent Mode (TM). In AM and UM, the RLC sublayer 602 provides segmentation of RLC SDUs. In AM, the RLC sublayer 602 provides ARQ (retransmission of RLC SDUs or RLC SDU segments).

[0066] The PDCP sublayer 603 provides Data Radio Bearers (DRBs) to the SDAP sublayer 604. The PDCP sublayer 603 receives user plane data of DRBs from the SDAP sublayer 604 and provides functions such as header compression, integrity protection, and ciphering.

[0067] In addition, the PDCP sublayer 603 provides Signalling Radio Bearers (SRBs) to the upper layers (i.e., the PC5-S layer, the PC-5 RRC layer). The PDCP sublayer 603 receives the control plane data of the SRBs (i.e., PC5-S messages and PC5-RRC messages) from the PC5-S layer and the PC-5 RRC layer, and provides integrity protection, ciphering, etc.

[0068] The SDAP sublayer 604 provides handling of Quality of Service (QoS) flows. The QoS flow may be an Internet Protocol (IP) flow, i.e., IP packets. Alternatively, the QoS flow may be a non-IP flow, i.e., non-IP packets. The SDAP sublayer 604 provides mapping between the QoS flow and the SL DRB. There is one SDAP entity for each destination for one of the unicast, groupcast, and broadcast associated with the destination.

[0069] The receiving UE (e.g., UE1B) performs Physical Sidelink Feedback Channel (PSFCH) transmission in response to the PSSCH received several slots ago. Whether a UE that has received a PSSCH transmission in a certain slot can transmit HARQ feedback for the PSSCH transmission in the PSFCH symbol several slots later depends on the period of the PSFCH symbol and further depends on the minimum time gap between the slot having the PSSCH transmission and the slot including the PSFCH for the HARQ feedback. Within a resource block, the resources for the PSFCH are periodically set, for example, with a period of 1, 2, or 4 slots. In other words, within the resource pool, there are slots with PSFCH every 1, 2, or 4 slots. Further, for each resource pool, the minimum number of slots (i.e., the minimum time gap) between the slot having the PSSCH transmission and the slot including the PSFCH for the HARQ feedback for the PSSCH transmission is set. The minimum time gap is, for example, 2 or 3.

[0070] Specifically, the configuration of PSFCH (e.g., SL-PSFCH-Config) including the configuration of PRBs used for PSFCH transmission and reception (e.g., sl-PSFCH-RB-Set), the configuration of the PSFCH period (e.g., sl-PSFCH-Period), and the configuration of the minimum time gap (e.g., sl-MinTimeGapPSFCH) can be included in the configuration of the sidelink resource pool. The configuration of the sidelink resource pool (e.g., SL-BWP-PoolConfigCommon) can be included in the sidelink common configuration (e.g., SL-BWP-ConfigCommon within SL-ConfigCommonNR) broadcast in the system information (e.g., System Information Block 12 (SIB12)). Alternatively, the configuration of the sidelink resource pool (e.g., SL-BWP-PoolConfig) can be included in the sidelink configuration (e.g., SL-BWP-PoolConfig within sl-ConfigDedicatedNR) transmitted in the UE-specific RRC message (e.g., RRCReconfiguration message). Alternatively, the configuration of the sidelink resource pool (e.g., SL-BWP-PoolConfigCommon) can be included in the sidelink configuration pre-configured for the UE (e.g., SL-BWP-PoolConfig within SL-PreconfigurationNR).

[0071] The receiving UE transmits the PSFCH in the first slot that includes the PSFCH resource and is located more than the number of slots specified by the minimum time gap configuration (e.g., sl-MinTimeGapPSFCH) of the resource pool from the last slot of the PSSCH reception. Therefore, if the PSFCH period is 4 slots, the HARQ feedback for the PSSCH transmission in 4 PSSCH slots can be transmitted in multiple PRBs within 1 PSFCH symbol in 1 slot.

[0072] <The First Embodiment> This embodiment provides an improvement regarding carrier aggregation in NR side link. Specifically, this embodiment relates to carrier aggregation using a first side link carrier to which resource allocation mode 1 is applied and a second side link carrier to which resource allocation mode 2 is applied. The configuration and operation of the wireless communication system and network element (or device, node, device, or network function) according to this embodiment may be the same as the examples described with reference to FIGS. 1 to 6.

[0073] FIG. 7 shows an example of the operation of UE1A. In step 701, UE1A uses a first side link carrier to which resource allocation mode 1 is applied and a second side link carrier to which resource allocation mode 2 is applied for side link communication with UE1B. Hereinafter, UE1B is called a peer UE, which means that UE1B is a communication partner or partner for the side link communication of UE1A. UE1B may be called a receiving UE. The side link communication may be unicast. The first side link carrier may belong to a licensed spectrum, and the second side link carrier may belong to an unlicensed spectrum. The unlicensed spectrum may be an ITS spectrum.

[0074] In step 702, UE1A generates a side link buffer status report (BSR) (i.e., Sidelink BSR MAC CE) to be transmitted to RAN node 2 in order to obtain a dynamic grant for the first side link carrier in consideration of the transmission status of transmission on the second side link carrier. In step 703, UE1A transmits the generated side link BSR to RAN node 2. The transmission status of transmission on the second side link carrier may be a transmission status estimated by UE1A. In other words, the transmission status of transmission on the second side link carrier may be a predicted future transmission status.

[0075] Specifically, it may not be preferable for UE1A to generate a sidelink BSR corresponding to the total data volume buffered in UE1A for transmission to peer UE1B. This is because such a sidelink BSR may obtain an excessive dynamic grant as it does not consider the data volume that can be offloaded to the second sidelink carrier. This may lead to a situation where the resources of the first sidelink carrier are consumed excessively or the resources of the second sidelink carrier cannot be utilized effectively. To address this problem, instead of generating a sidelink BSR corresponding to the total data volume, UE1A may subtract the estimated data volume that can be transmitted on the second sidelink carrier from the total data volume, thereby obtaining an appropriately sized dynamic grant.

[0076] The generation of the sidelink BSR in step 702 may be performed as follows. UE1A may estimate the data size, data rate, or traffic pattern of transmission on the second sidelink carrier. Then, UE1A may generate a sidelink BSR for obtaining a dynamic grant for transmission on the first sidelink carrier in consideration of the estimated data size, data rate, or traffic pattern.

[0077] UE1A may generate a sidelink BSR by reducing the total data volume buffered in UE1A for transmission to peer UE1B based on the estimated transmission situation (e.g., data size, data rate, or traffic pattern) of transmission on the second sidelink carrier.

[0078] UE1A may generate a sidelink BSR by excluding the estimated data volume that can be transmitted on the second sidelink carrier from the total data volume buffered in UE1A for transmission to peer UE1B.

[0079] UE1A may generate a sidelink BSR to obtain a dynamic grant for transmitting on the first sidelink carrier, considering the size (or bandwidth) of the transmission resource pool of the first sidelink carrier and the size (or bandwidth) of the transmission resource pool of the second sidelink carrier. Specifically, UE1A may consider the ratio of the size of the transmission resource pool of the first sidelink carrier to the sum of the sizes of the transmission resource pools of the first and second sidelink carriers. As an example, UE1A may calculate an adjusted or modified total data volume D2 based on the following formula (1):

Number

[0080] UE1A may generate a sidelink BSR to obtain a dynamic grant for transmitting on the first sidelink carrier, considering the Channel Busy Ratio (CBR) of the first sidelink carrier and the CBR of the second sidelink carrier. UE1A may correct the size W1 of the transmission resource pool of the first sidelink carrier using the CBR value CBR1 of the first sidelink carrier. Similarly, UE1A may correct the size W2 of the transmission resource pool of the second sidelink carrier using the CBR value CBR2 of the second sidelink carrier. As an example, UE1A may calculate an adjusted or modified total data volume D2 based on the following formula (2):

Number

[0081] UE1A may generate a sidelink BSR to obtain a dynamic grant for transmission on the first sidelink carrier, considering the Sidelink Reference Signal Received Power (SL-RSRP) of the first sidelink carrier and the SL-RSRP of the second sidelink carrier. The SL-RSRP measurements for multiple candidate carrier frequencies may be performed by UE1 itself. Alternatively, UE1 may receive SL-RSRP measurement results from one or more other UEs. UE1A may correct the size W1 of the transmission resource pool for the first sidelink carrier using the Modulation and Coding Scheme (MCS) value MCS1 of the first sidelink carrier. Similarly, UE1A may correct the size W2 of the transmission resource pool for the second sidelink carrier using the MCS value MCS2 of the second sidelink carrier. The MCS is selected based on the measurement results of the SL-RSRP. As an example, UE1A may calculate the total data volume D2 adjusted or modified based on the following formula (3):

Number

[0082] According to the operation of UE1 described with reference to FIG. 7, UE1 can generate a sidelink BSR to obtain a dynamic grant for transmission on the first sidelink carrier to which resource allocation mode 1 is applied, considering transmission on the second sidelink carrier to which resource allocation mode 2 is applied. This can contribute to avoiding, for example, UE1 obtaining an excessive dynamic grant that exceeds the actual amount required for transmission on the first sidelink carrier.

[0083] <Second Embodiment> This embodiment provides an improvement related to carrier aggregation in NR side links. Specifically, this embodiment relates to carrier aggregation using a first side link carrier to which resource allocation mode 1 is applied and a second side link carrier to which resource allocation mode 2 is applied. The configuration and operation of the wireless communication system and network element (or device, node, device, or network function) according to this embodiment may be the same as the example described with reference to FIGS. 1 to 6.

[0084] FIG. 8 shows an example of the operation of UE1A. The operation shown in FIG. 8 is similar to that shown in FIG. 7. However, FIG. 7 relates to the transmission of a side link BSR to obtain a dynamic grant, while FIG. 8 relates to the transmission of side link traffic pattern information to obtain a configured grant.

[0085] Step 801 in FIG. 8 is the same as step 701 in FIG. 7. Specifically, UE1A uses a first side link carrier to which resource allocation mode 1 is applied and a second side link carrier to which resource allocation mode 2 is applied for side link communication with peer UE1B. The side link communication may be unicast. The first side link carrier may belong to a licensed spectrum, and the second side link carrier may belong to an unlicensed spectrum. The unlicensed spectrum may be an ITS spectrum.

[0086] In step 802, UE1A generates sidelink traffic pattern information to be transmitted to RAN node 2 to obtain a configured grant for the first sidelink carrier, considering the transmission status of transmissions on the second sidelink carrier. The sidelink traffic pattern information may be referred to as configured grant assistance information. The sidelink traffic pattern information may indicate the maximum transport block size based on the observed traffic pattern. Additionally or alternatively, the sidelink traffic pattern information may indicate the estimated arrival timing of packets in the sidelink logical channel. Additionally or alternatively, the sidelink traffic pattern information may indicate the estimated data arrival period in the sidelink logical channel. In step 803, UE1A transmits UE assistance information including the generated sidelink traffic pattern information to RAN node 2 using an RRC message. The RRC message may be a UEassistanceinformation message.

[0087] Specifically, when obtaining the configured grant for the first sidelink carrier, UE1A may preferably generate the sidelink traffic pattern information by excluding traffic that can be periodically transmitted on the second sidelink carrier. This can contribute to avoiding UE1A from obtaining an excessive configured grant.

[0088] The generation of the sidelink traffic pattern information in step 802 may be performed as follows. UE1A may estimate the data size, data rate, or traffic pattern of transmissions on the second sidelink carrier. Then, UE1A may generate sidelink traffic pattern information for obtaining a configured grant for the transmission of the first sidelink carrier, considering the estimated data size, data rate, or traffic pattern.

[0089] UE1A may generate sidelink traffic pattern information to indicate the estimated traffic pattern of transmissions on the first sidelink carrier, except for the estimated traffic pattern of transmissions on the second sidelink carrier.

[0090] According to the operation of UE1 described with reference to FIG. 8, UE1 can generate sidelink traffic pattern information for obtaining a configured grant for transmissions on the first sidelink carrier, taking into account transmissions on the second sidelink carrier. This can contribute to, for example, avoiding UE1 from obtaining an excessive configured grant that exceeds the amount actually required for transmissions on the first sidelink carrier.

[0091] <The Third Embodiment> This embodiment provides an improvement related to carrier aggregation in NR sidelink. Specifically, this embodiment relates to carrier aggregation using a first sidelink carrier to which resource allocation mode 1 is applied and a second sidelink carrier to which resource allocation mode 2 is applied. The configuration and operation of the wireless communication system and network element (or device, node, device, or network function) according to this embodiment may be the same as the example described with reference to FIGS. 1 to 6.

[0092] FIG. 9 shows an example of the operation of UE1A. The operation shown in FIG. 9 is similar to that shown in FIG. 7. However, FIG. 7 relates to the generation of an adjusted or modified sidelink BSR by UE1A, while FIG. 9 is different from FIG. 7 in that FIG. 9 relates to the transmission of assistance information for assisting the RAN node 2 in estimating the transmission status of transmissions on the second sidelink carrier.

[0093] Step 901 is the same as step 701 in FIG. 7. Specifically, UE1A uses a first sidelink carrier to which resource allocation mode 1 is applied and a second sidelink carrier to which resource allocation mode 2 is applied for sidelink communication with peer UE1B. The sidelink communication may be unicast. The first sidelink carrier may belong to licensed spectrum, and the second sidelink carrier may belong to unlicensed spectrum. The unlicensed spectrum may be ITS spectrum.

[0094] In step 902, UE1A transmits a sidelink BSR (i.e., Sidelink BSR MAC CE) to RAN node 2 to obtain a dynamic grant for the first sidelink carrier. UE1 may generate a sidelink BSR corresponding to the total data volume buffered in UE1A for transmission to peer UE1B.

[0095] In step 903, UE1A transmits assistance information used to obtain the transmission status of transmission on the second sidelink carrier to RAN node 2. The order of the transmission in step 902 and the transmission in step 903 shown in FIG. 9 is an example and is not limited thereto. The assistance information in step 903 may be transmitted before, simultaneously with, or after the sidelink BSR in step 902. The assistance information in step 903 may be transmitted using an RRC message or a MAC CE. This RRC message may be a MeasurementReport message, a UEassistanceinformation message, or a SIdelinkUEinformationNR message.

[0096] The assistance information in step 903 may indicate the size (or bandwidth) of the transmission resource pool of the second sidelink carrier. Further or alternatively, the assistance information may indicate one or any combination of the CBR, SL-RSRP, and Sidelink Channel State Information (SL-CSI) of the second sidelink carrier.

[0097] Figure 10 shows an example of the operation of RAN node 2. In step 1001, RAN node 2 receives a sidelink BSR (i.e., Sidelink BSR MAC CE) from UE1A to obtain a dynamic grant for the first sidelink carrier to which resource allocation mode 1 is applied.

[0098] In step 1002, RAN node 2 receives assistance information regarding the second sidelink carrier to which resource allocation mode 2 is applied from UE1A. The order of the reception in step 1001 and the reception in step 1002 shown in Figure 10 is an example and is not limited thereto. The assistance information in step 1002 may be received before, simultaneously with, or after the sidelink BSR in step 1001. The assistance information in step 1002 may be transmitted using an RRC message or a MAC CE. This RRC message may be a MeasurementReport message, a UEassistanceinformation message, or a SIdelinkUEinformationNR message.

[0099] The assistance information in step 1002 may indicate the size (or bandwidth) of the transmission resource pool of the second sidelink carrier. Further or alternatively, the assistance information may indicate one or any combination of the CBR, SL-RSRP, and SL-CSI of the second sidelink carrier.

[0100] In step 1003, RAN node 2 generates a dynamic grant considering the transmission status of transmissions on the second sidelink carrier obtained based on the assistance information. In step 1004, RAN node 2 transmits the generated dynamic grant to UE1A. The transmission status of transmissions on the second sidelink carrier may be the transmission status estimated by RAN node 2 based on the assistance information. In other words, the transmission status of transmissions on the second sidelink carrier may be the predicted future transmission status.

[0101] RAN node 2 may consider the estimated transmission status of transmissions on the second sidelink carrier in the same manner as the operation of UE1A described with reference to FIG. 7. Specifically, instead of generating a dynamic grant directly based on the sidelink BSR, RAN node 2 may subtract the estimated data volume that can be transmitted on the second sidelink carrier from the total data volume, thereby generating a dynamic grant of an appropriate size.

[0102] The generation of the dynamic grant in step 1003 may be performed as follows. RAN node 2 may estimate the data size, data rate, or traffic pattern of transmissions on the second sidelink carrier. Then, RAN node 2 may generate a dynamic grant for the transmission on the first sidelink carrier considering the estimated data size, data rate, or traffic pattern.

[0103] RAN node 2 may generate a dynamic grant by reducing the total data volume indicated in the sidelink BSR based on the estimated transmission status (e.g., data size, data rate, or traffic pattern) of transmissions on the second sidelink carrier.

[0104] RAN node 2 may generate a dynamic grant by excluding the estimated data volume that can be transmitted on the second sidelink carrier from the total data volume indicated in the sidelink BSR.

[0105] The method for adjusting or modifying the total data volume indicated by the sidelink BSR may be the same as any of the plurality of examples described in the first embodiment.

[0106] According to the operations of the UE1 and the RAN node 2 described with reference to FIGS. 9 and 10, the RAN node 2 can generate a dynamic grant for transmission on the first sidelink carrier in consideration of transmission on the second sidelink carrier. This can contribute to, for example, avoiding the UE1 from obtaining an excessive dynamic grant that exceeds the amount actually required for transmission on the first sidelink carrier.

[0107] <Fourth Embodiment> This embodiment provides an improvement related to carrier aggregation in NR sidelink. Specifically, this embodiment relates to carrier aggregation using a first sidelink carrier to which resource allocation mode 1 is applied and a second sidelink carrier to which resource allocation mode 2 is applied. The configuration and operations of the wireless communication system and network element (or apparatus, node, device, or network function) according to this embodiment may be the same as the examples described with reference to FIGS. 1 to 6.

[0108] FIG. 11 shows an example of the operation of the UE1A. The operation shown in FIG. 11 is similar to that shown in FIG. 9. However, FIG. 9 relates to the transmission of the sidelink BSR to obtain a dynamic grant, while FIG. 11 relates to the transmission of sidelink traffic pattern information to obtain a configured grant.

[0109] Step 1101 in FIG. 11 is the same as step 901 in FIG. 9. Specifically, UE1A uses, for sidelink communication with peer UE1B, a first sidelink carrier to which resource allocation mode 1 is applied and a second sidelink carrier to which resource allocation mode 2 is applied. The sidelink communication may be unicast. The first sidelink carrier may belong to licensed spectrum, and the second sidelink carrier may belong to unlicensed spectrum. The unlicensed spectrum may be ITS spectrum.

[0110] In step 1101, UE1A transmits sidelink traffic pattern information for obtaining the configured grant of the first sidelink carrier to RAN node 2. Specifically, UE1A transmits UE assistance information including the sidelink traffic pattern information to RAN node 2 using an RRC message. The RRC message may be a UEassistanceinformation message. The sidelink traffic pattern information may be referred to as configured grant assistance information. The sidelink traffic pattern information may indicate the maximum transport block size based on the observed traffic pattern. Additionally or alternatively, the sidelink traffic pattern information may indicate the estimated timing of packet arrival in the sidelink logical channel. Additionally or alternatively, the sidelink traffic pattern information may indicate the estimated data arrival period in the sidelink logical channel.

[0111] In step 1103, UE1A transmits to RAN node 2 the assistance information used to obtain the transmission status of transmissions on the second sidelink carrier. The order of the transmission in step 1102 and the transmission in step 1103 shown in FIG. 11 is an example and is not limited thereto. The assistance information in step 1103 may be transmitted before, simultaneously with, or after the sidelink traffic pattern information in step 1102. The assistance information in step 1103 may be transmitted using an RRC message or a MAC CE. This RRC message may be a MeasurementReport message, a UEassistanceinformation message, or a SIdelinkUEinformationNR message.

[0112] The assistance information in step 1103 may indicate the size (or bandwidth) of the transmission resource pool of the second sidelink carrier. Further or alternatively, the assistance information may indicate one or any combination of CBR, SL-RSR, and SL-CSI of the second sidelink carrier.

[0113] FIG. 12 shows an example of the operation of RAN node 2. The operation shown in FIG. 12 is similar to that shown in FIG. 10. However, FIG. 10 relates to the generation of dynamic grants, while FIG. 12 relates to the generation of configured grants.

[0114] In step 1201, RAN node 2 receives from UE1A the sidelink traffic pattern information for obtaining the configured grant of the first sidelink carrier to which resource allocation mode 1 is applied. Specifically, RAN node 2 receives, via an RRC message, the UE assistance information including the sidelink traffic pattern information. The RRC message may be a UEassistanceinformation message.

[0115] In step 1202, the RAN node 2 receives assistance information regarding the second sidelink carrier to which the resource allocation mode 2 is applied from the UE1A. The order of the reception in step 1201 and the reception in step 1202 shown in FIG. 12 is an example and is not limited thereto. The assistance information in step 1202 may be received before, simultaneously with, or after the sidelink traffic pattern information in step 1201. The assistance information in step 1202 may be transmitted using an RRC message or a MAC CE. This RRC message may be a MeasurementReport message, a UEassistanceinformation message, or a SIdelinkUEinformationNR message.

[0116] The assistance information in step 1202 may indicate the size (or bandwidth) of the transmission resource pool of the second sidelink carrier. Further or alternatively, the assistance information may indicate one or any combination of the CBR, SL-RSRP, and SL-CSI of the second sidelink carrier.

[0117] In step 1203, the RAN node 2 generates a configured grant in consideration of the transmission status of transmission on the second sidelink carrier obtained based on the assistance information. In step 1204, the RAN node 2 transmits the generated configured grant to the UE1A.

[0118] The RAN node 2 may consider the (estimated) transmission status of transmission on the second sidelink carrier in the same manner as the operation of the UE1A described with reference to FIG. 8. Specifically, the RAN node 2 may generate a configured grant by excluding the estimated traffic pattern of transmission on the second sidelink carrier from the traffic pattern indicated by the sidelink traffic pattern information.

[0119] According to the operations of UE1 and RAN Node 2 described with reference to FIGS. 11 and 12, RAN Node 2 can generate a configured grant for transmission on a first sidelink carrier in consideration of transmission on a second sidelink carrier. This can contribute to, for example, avoiding UE1 from obtaining an excessive configured grant that exceeds the amount actually required for transmission on the first sidelink carrier.

[0120] <Fifth Embodiment> This embodiment provides an improvement regarding carrier aggregation in NR sidelink. Specifically, this embodiment relates to carrier aggregation using a first sidelink carrier to which resource allocation mode 1 is applied and a second sidelink carrier to which resource allocation mode 2 is applied. The configuration and operation of the wireless communication system and network element (or apparatus, node, device, or network function) according to this embodiment may be the same as the example described with reference to FIGS. 1 to 6.

[0121] FIG. 13 shows an example of the operation of UE1A. The operation in FIG. 13 relates to the coordination or prioritization between transmission on a first sidelink carrier to which resource allocation mode 1 is applied and transmission on a second sidelink carrier to which resource allocation mode 2 is applied.

[0122] In step 1301, UE1A uses a first sidelink carrier to which resource allocation mode 1 is applied and a second sidelink carrier to which resource allocation mode 2 is applied for sidelink communication with peer UE1B. The sidelink communication may be unicast. The first sidelink carrier may belong to licensed spectrum, and the second sidelink carrier may belong to unlicensed spectrum. The unlicensed spectrum may be ITS spectrum.

[0123] In step 1302, when there is data to be transmitted and the resources of the second sidelink carrier are also available in the time slot of the first sidelink carrier for which a dynamic grant or a configured grant has been obtained, UE1A determines, according to a predetermined rule, whether to transmit the data on the first sidelink carrier or the second sidelink carrier. This process may be performed by the MAC sublayer 601 (MAC entity) of UE1A.

[0124] The said predetermined rule may be referred to as, for example, a coordination rule, a coordination policy, a prioritization rule, a prioritization policy, a carrier selection rule, or a carrier selection policy.

[0125] The predetermined rule or one or more parameters for defining the predetermined rule may be preconfigured in UE1A. UE1A may store the predetermined rule or one or more parameters for defining the predetermined rule in a non-volatile memory in the Mobile Equipment (ME) or the Universal Subscriber Identity Module (USIM). UE1A may receive the predetermined rule or one or more parameters for defining the predetermined rule from a core network node (e.g., AMF41, PCF44) via the N1 reference point between AMF41 and UE1. Alternatively, UE1A may receive these via the V1 reference point between UE1 and the V2X application server 61 from the V2X application server 61.

[0126] As shown in FIG. 14, UE1A may receive signaling indicating the predetermined rule or one or more parameters for defining the predetermined rule from the RAN node 2 (step 1401). This signaling may be UE-non-specific signaling (e.g., broadcast of system information) or UE-specific signaling (e.g., RRC signaling).

[0127] An example of the determination based on a predetermined rule in step 1302 will be described below. The examples shown below may be combined as appropriate.

[0128] The first example relates to the case where the radio transceiver of UE1A can simultaneously perform transmissions on the first and second sidelink carriers in the time domain. In other words, the first example relates to the case where UE1A does not have limited Tx capability. The same applies to the second to sixth examples below. In the first example, the predetermined rule includes preferentially transmitting data on the first sidelink carrier. In other words, UE1A preferentially transmits data on the first sidelink carrier.

[0129] The second example is a variation of the first example. In the second example, the predetermined rule includes, if there is remaining data that cannot be included in the first transport block transmitted on the first sidelink carrier in a time slot based on a dynamic grant or a configured grant, including the remaining data in the second transport block transmitted on the second sidelink carrier. In other words, if there is remaining data that cannot be included in the first transport block transmitted on the first sidelink carrier in a time slot based on a dynamic grant or a configured grant, UE1A (MAC sublayer 601 or MAC entity) includes the remaining data in the second transport block transmitted on the second sidelink carrier.

[0130] The third example relates to the case where the radio transceiver of UE1A can simultaneously perform transmissions on the first and second sidelink carriers in the time domain. In the third example, the predetermined rule includes selecting the carrier with the lower CBR among the two carriers if the difference between the CBR of the first sidelink carrier and the CBR of the second sidelink carrier exceeds a threshold, and otherwise selecting both carriers. In other words, if the difference between the CBR of the first sidelink carrier and the CBR of the second sidelink carrier exceeds a threshold, UE1A selects the carrier with the lower CBR among the two carriers, and otherwise selects both carriers.

[0131] The fourth example relates to the case where the radio transceiver of UE1A can simultaneously perform transmissions on the first and second sidelink carriers in the time domain. In the fourth example, the predetermined rule includes selecting the carrier with the better SL-RSRP among the two carriers if the difference between the SL-RSRP of the first sidelink carrier and the SL-RSRP of the second sidelink carrier exceeds a threshold, and otherwise selecting both carriers. In other words, if the difference between the SL-RSRP of the first sidelink carrier and the SL-RSRP of the second sidelink carrier exceeds a threshold, UE1A selects the carrier with the better SL-RSRP among the two carriers, and otherwise selects both carriers.

[0132] The fifth example relates to the case where the radio transceiver of UE1A can simultaneously perform transmissions on the first and second sidelink carriers in the time domain. In the fifth example, the predetermined rule includes selecting one or both of the first and second sidelink carriers whose CBR is lower than a threshold. In other words, UE1A selects one or both of the first and second sidelink carriers whose CBR is lower than a threshold.

[0133] The sixth example relates to the case where the radio transceiver of UE1A can simultaneously perform transmissions on the first and second sidelink carriers in the time domain. In the sixth example, the predetermined rule includes selecting one or both of the first and second sidelink carriers whose CBR is lower than a threshold. In other words, if UE1A can simultaneously perform transmissions on the first and second sidelink carriers in the time domain, UE1A selects one or both of the first and second sidelink carriers whose SL-RSRP is better than a threshold. In other words, if UE1A can simultaneously perform transmissions on the first and second sidelink carriers in the time domain, UE1A selects one or both of the first and second sidelink carriers whose SL-RSRP is better than a threshold.

[0134] The seventh example relates to the case where the radio transceiver of UE1A cannot simultaneously perform transmissions on the first and second sidelink carriers in the time domain. In other words, the seventh example relates to the case where UE1A has a limited Tx capability. The same applies to the following eighth to eleventh examples. In the seventh example, the predetermined rule includes preferentially transmitting data on the first sidelink carrier. In other words, UE1A preferentially transmits data on the first sidelink carrier.

[0135] The eighth example relates to the case where the radio transceiver of UE1A cannot simultaneously perform transmissions on the first and second sidelink carriers in the time domain. In the eighth example, the predetermined rule includes selecting the second sidelink carrier if the CBR of the second sidelink carrier is lower than the threshold by more than the CBR of the first sidelink carrier, and otherwise selecting the first sidelink carrier. In other words, UE1A selects the second sidelink carrier if the CBR of the second sidelink carrier is lower than the threshold by more than the CBR of the first sidelink carrier, and otherwise selects the first sidelink carrier.

[0136] Example 9 relates to the case where the radio transceiver of UE1A cannot simultaneously perform transmissions on the first and second sidelink carriers in the time domain. In Example 9, the predetermined rule includes selecting the second sidelink carrier if the SL-RSRP of the second sidelink carrier may exceed the threshold than the SL-RSRP of the first sidelink carrier, and otherwise selecting the first sidelink carrier. In other words, UE1A selects the second sidelink carrier if the SL-RSRP of the second sidelink carrier may exceed the threshold than the SL-RSRP of the first sidelink carrier, and otherwise selects the first sidelink carrier.

[0137] Example 10 relates to the case where the radio transceiver of UE1A cannot simultaneously perform transmissions on the first and second sidelink carriers in the time domain. In Example 10, the predetermined rule includes selecting the one of the first sidelink carrier and the second sidelink carrier whose CBR is lower than the other. In other words, UE1A selects the one of the first sidelink carrier and the second sidelink carrier whose CBR is lower than the other.

[0138] Example 11 relates to the case where the radio transceiver of UE1A cannot simultaneously perform transmissions on the first and second sidelink carriers in the time domain. In Example 11, the predetermined rule includes selecting the one of the first sidelink carrier and the second sidelink carrier whose SL-RSRP is better than the other. In other words, UE1A selects the one of the first sidelink carrier and the second sidelink carrier whose SL-RSRP is better than the other.

[0139] According to the operation of UE1 described in this embodiment, UE1 can coordinate or prioritize between transmissions on carriers to which resource allocation mode 1 is applied and transmissions on carriers to which resource allocation mode 2 is applied.

[0140] Next, a configuration example of the UE1, RAN node 2, core network nodes such as the AMF 41, and the V2X application server 61 according to the above-described plurality of embodiments will be described below. FIG. 15 is a block diagram showing a configuration example of the UE1. The Radio Frequency (RF) transceiver **********

[0141] It seems there is some text missing in the translation of ID=1. Please check and provide the complete original text if needed.The baseband processor 1503 performs digital baseband signal processing (data plane processing) and control plane processing for wireless communication. The digital baseband signal processing includes (a) data compression / decompression, (b) data segmentation / concatenation, (c) generation / decomposition of a transmission format (transmission frame), (d) channel coding / decoding, (e) modulation (symbol mapping) / demodulation, and (f) generation of OFDM symbol data (baseband OFDM signal) by Inverse Fast Fourier Transform (IFFT), etc. On the other hand, the control plane processing includes communication management of layer 1 (e.g., transmission power control), layer 2 (e.g., radio resource management, and hybrid automatic repeat request (HARQ) processing), and layer 3 (e.g., signaling related to attachment, mobility, and call management).

[0142] For example, the digital baseband signal processing by the baseband processor 1503 may include signal processing of the Service Data Adaptation Protocol (SDAP) layer, Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer, Medium Access Control (MAC) layer, and Physical (PHY) layer. Also, the control plane processing by the baseband processor 1503 may include processing of the Non-Access Stratum (NAS) protocol, Radio Resource Control (RRC) protocol, MAC Control Elements (CEs), and Downlink Control Information (DCIs). The control plane processing may include processing of PC5-S signaling and PC5-RRC signaling.

[0143] The baseband processor 1503 may perform Multiple Input Multiple Output (MIMO) encoding and precoding for beamforming.

[0144] The baseband processor 1503 may include a modem processor (e.g., Digital Signal Processor (DSP)) that performs digital baseband signal processing and a protocol stack processor (e.g., Central Processing Unit (CPU) or Micro Processing Unit (MPU)) that performs control plane processing. In this case, the protocol stack processor that performs control plane processing may be shared with the application processor 1504 described later.

[0145] The application processor 1504 is also referred to as a CPU, MPU, microprocessor, or processor core. The application processor 1504 may include a plurality of processors (a plurality of processor cores). The application processor 1504 realizes various functions of the UE1 by executing a system software program (Operating System (OS)) and various application programs (e.g., call application, WEB browser, mailer, camera operation application, music playback application) read from the memory 1506 or other memory.

[0146] In some implementations, as shown by the dashed line (1505) in FIG. 15, the baseband processor 1503 and the application processor 1504 may be integrated on one chip. In other words, the baseband processor 1503 and the application processor 1504 may be implemented as one System on Chip (SoC) device 1505. The SoC device may also be referred to as a system Large Scale Integration (LSI) or a chipset.

[0147] The memory 1506 is a volatile memory, a non-volatile memory, or a combination thereof. The memory 1506 may include a plurality of physically independent memory devices. The volatile memory is, for example, Static Random Access Memory (SRAM), Dynamic RAM (DRAM), or a combination thereof. The non-volatile memory is a mask Read Only Memory (MROM), Electrically Erasable Programmable ROM (EEPROM), flash memory, or a hard disk drive, or any combination thereof. For example, the memory 1506 may include an external memory device accessible from the baseband processor 1503, the application processor 1504, and the SoC 1505. The memory 1506 may include an embedded memory device integrated within the baseband processor 1503, within the application processor 1504, or within the SoC 1505. Further, the memory 1506 may include a memory within a Universal Integrated Circuit Card (UICC).

[0148] The memory 1506 may store one or more software modules (computer programs) 1507 including instruction groups and data for performing the processing by the UE1 described in the above-described embodiments. In some implementations, the baseband processor 1503 or the application processor 1504 may be configured to perform the processing of the UE1 described with reference to the drawings in the above-described embodiments by reading and executing the software module 1507 from the memory 1506.

[0149] Note that the control plane processing and operations performed by the UE1 described in the above-described embodiments can be realized by other elements excluding the RF transceiver 1501 and the antenna array 1502, that is, at least one of the baseband processor 1503 and the application processor 1504 and the memory 1506 storing the software module 1507.

[0150] FIG. 16 is a block diagram showing a configuration example of the RAN node 2 according to the above-described embodiment. Referring to FIG. 16, the RAN node 2 includes a Radio Frequency transceiver 1601, a network interface 1603, a processor 1604, and a memory 1605. The RF transceiver 1601 performs analog RF signal processing to communicate with UEs1 and other UEs. The RF transceiver 1601 may include a plurality of transceivers. The RF transceiver 1601 is coupled to the antenna array 1602 and the processor 1604. The RF transceiver 1601 receives modulation symbol data from the processor 1604, generates a transmission RF signal, and supplies the transmission RF signal to the antenna array 1602. Also, the RF transceiver 1601 generates a baseband reception signal based on the reception RF signal received by the antenna array 1602 and supplies this to the processor 1604. The RF transceiver 1601 may include an analog beamformer circuit for beamforming. The analog beamformer circuit includes, for example, a plurality of phase shifters and a plurality of power amplifiers.

[0151] The network interface 1603 is used to communicate with network nodes (e.g., other RAN nodes, as well as control nodes and transfer nodes of the core network). The network interface 1603 may include, for example, a network interface card (NIC) compliant with the IEEE 802.3 series.

[0152] Processor 1604 performs digital baseband signal processing (data plane processing) and control plane processing for wireless communication. Processor 1604 may include a plurality of processors. For example, Processor 1604 may include a modem processor (e.g., Digital Signal Processor (DSP)) that performs digital baseband signal processing and a protocol stack processor (e.g., Central Processing Unit (CPU) or Micro Processing Unit (MPU)) that performs control plane processing. Processor 1604 may include a digital beamformer module for beamforming. The digital beamformer module may include a Multiple Input Multiple Output (MIMO) encoder and a precoder.

[0153] Memory 1605 is composed of a combination of volatile memory and non-volatile memory. The volatile memory is, for example, Static Random Access Memory (SRAM) or Dynamic RAM (DRAM) or a combination thereof. The non-volatile memory is a mask Read Only Memory (MROM), Electrically Erasable Programmable ROM (EEPROM), flash memory, or a hard disk drive, or any combination thereof. Memory 1605 may include storage located remotely from Processor 1604. In this case, Processor 1604 may access Memory 1605 via Network Interface 1603 or another I / O interface.

[0154] Memory 1605 may store one or more software modules (computer programs) 1606 containing instruction groups and data for performing the processing by the RAN node 2 described in the above-described embodiments. In some implementations, the processor 1604 may be configured to read and execute the software module 1606 from the memory 1605 to perform the processing of the RAN node 2 described in the above-described embodiments.

[0155] Note that when the RAN node 2 is a Central Unit (CU) (e.g., gNB-CU) or a CU Control Plane Unit (CU-CP) (e.g., gNB-CU-CP), the RAN node 2 may not include the RF transceiver 1601 (and the antenna array 1602).

[0156] FIG. 17 shows a configuration example of the AMF 41. Other core network nodes within the 5GC 40 and the V2X application server 61E may also have a configuration similar to that shown in FIG. 17. Referring to FIG. 17, the AMF 41 includes a network interface 1701, a processor 1702, and a memory 1703. The network interface 1701 is used, for example, to communicate with other network functions (NFs) or nodes. The network interface 1701 may include, for example, a network interface card (NIC) compliant with the IEEE 802.3 series.

[0157] The processor 1702 may be, for example, a microprocessor, a Micro Processing Unit (MPU), or a Central Processing Unit (CPU). The processor 1702 may include a plurality of processors.

[0158] Memory 1703 is composed of volatile memory and non-volatile memory. Memory 1703 may physically include a plurality of independent memory devices. The volatile memory is, for example, Static Random Access Memory (SRAM), Dynamic RAM (DRAM), or a combination thereof. The non-volatile memory is Mask Read Only Memory (MROM), Electrically Erasable Programmable ROM (EEPROM), flash memory, or a hard disk drive, or any combination thereof. Memory 1703 may include storage located away from processor 1702. In this case, processor 1702 may access memory 1703 via network interface 1701 or other I / O interface.

[0159] Memory 1703 may store one or more software modules (computer programs) 1704 including instruction groups and data for performing the processing by AMF41 described in the above-described embodiments. In some implementations, processor 1702 may be configured to perform the processing of AMF41 described in the above embodiments by reading and executing the software module 1704 from memory 1703.

[0160] As described with reference to FIGS. 15, 16, and 17, each of the processors included in the UE 1, the RAN node 2, the core network nodes such as the AMF 41, and the V2X application server 61 according to the above-described embodiments can execute one or more programs including a set of instructions for causing a computer to perform the algorithms described with reference to the drawings. The program includes a set of instructions (or software code) for causing a computer to perform one or more functions described in the embodiments when loaded into the computer. The program may be stored in a non-transitory computer-readable medium or a tangible storage medium. By way of example and not limitation, the computer-readable medium or tangible storage medium includes random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD), or other memory technologies, CD-ROM, digital versatile disk (DVD), Blu-ray (registered trademark) disk, or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage, or other magnetic storage devices. The program may be transmitted on a transient computer-readable medium or a communication medium. By way of example and not limitation, the transient computer-readable medium or communication medium includes electrical, optical, acoustic, or other forms of propagated signals.

[0161] The above-described embodiments are merely examples of the application of the technical idea obtained by the present inventor. That is, the technical idea is not limited to the above-described embodiments, and various modifications are of course possible.

[0162] For example, some or all of the above embodiments may be described as follows in the appended claims, but are not limited thereto.

[0163] (Appended Claim 1) A wireless terminal, at least one wireless transceiver, at least one processor coupled to the at least one wireless transceiver, The at least one processor uses a first sidelink carrier to which a first resource allocation mode in which resources are allocated by a radio access network node is applied and a second sidelink carrier to which a second resource allocation mode in which the wireless terminal autonomously selects resources is applied for sidelink communication with a peer wireless terminal, generates one or both of a buffer status report and traffic pattern information in consideration of a transmission status of transmission on the second sidelink carrier, and transmits one or both of the buffer status report and the traffic pattern information to the radio access network node. is configured as a wireless terminal. (Appendix 2) The at least one processor is configured to generate the buffer status report by reducing a total data volume buffered in the wireless terminal for transmission to the peer wireless terminal based on a transmission status of transmission on the second sidelink carrier. The wireless terminal according to Appendix 1. (Appendix 3) The at least one processor is configured to generate the buffer status report by excluding an estimated data volume that can be transmitted on the second sidelink carrier from a total data volume buffered in the wireless terminal for transmission to the peer wireless terminal. The wireless terminal according to Appendix 1 or 2. (Appendix 4) The at least one processor is configured to generate the traffic pattern information so as to indicate an estimated traffic pattern of transmission on the first sidelink carrier excluding an estimated traffic pattern of transmission on the second sidelink carrier. The wireless terminal according to any one of Appendices 1 to 3. (Appendix 5) The traffic pattern information includes one or both of an estimated data arrival periodicity and a maximum transport block size. 5. The wireless terminal according to any one of Supplementary notes 1 to 4. (Appendix 6) the at least one processor is configured to generate the buffer status report and / or the traffic pattern information using a Channel Busy Ratio (CBR) of the second sidelink carrier or a Sidelink Reference Signal Received Power (SL-RSRP) of the second sidelink carrier. 6. The wireless terminal according to any one of Supplementary notes 1 to 5. (Appendix 7) the first sidelink carrier belongs to a licensed spectrum of the radio access network node and the second sidelink carrier belongs to an unlicensed spectrum; 7. The wireless terminal according to claim 1. (Appendix 8) the transmission status of the transmission on the second sidelink carrier is a transmission status estimated by the wireless terminal; 8. The wireless terminal according to any one of Supplementary notes 1 to 7. (Appendix 9) the buffer status report is sent to the radio access network node for obtaining a dynamic grant for the first sidelink carrier; the traffic pattern information is transmitted to the radio access network node to obtain a configured grant for the first sidelink carrier. 9. The wireless terminal according to any one of Supplementary notes 1 to 8. (Appendix 10) 1. A method performed by a wireless terminal, comprising: A first sidelink carrier to which a first resource allocation mode in which resources are allocated by a radio access network node is applied and a second sidelink carrier to which a second resource allocation mode in which the radio terminal autonomously selects resources is applied are used for sidelink communication with a peer radio terminal, generate one or both of a buffer status report and traffic pattern information in consideration of a transmission status of transmission on the second sidelink carrier, transmit one or both of the buffer status report and the traffic pattern information to the radio access network node, A method comprising the steps of: (Appendix 11) A program for causing a computer to perform a method for a radio terminal, wherein the method comprises: A first sidelink carrier to which a first resource allocation mode in which resources are allocated by a radio access network node is applied and a second sidelink carrier to which a second resource allocation mode in which the radio terminal autonomously selects resources is applied are used for sidelink communication with a peer radio terminal, generate one or both of a buffer status report and traffic pattern information in consideration of a transmission status of transmission on the second sidelink carrier, transmit one or both of the buffer status report and the traffic pattern information to the radio access network node, A program comprising the steps of: (Appendix 12) A radio terminal, at least one radio transceiver, and at least one processor coupled to the at least one radio transceiver, wherein the at least one processor is A first sidelink carrier to which a first resource allocation mode in which resources are allocated by a radio access network node is applied and a second sidelink carrier to which a second resource allocation mode in which the wireless terminal autonomously selects resources are applied are used for sidelink communication with a peer wireless terminal, transmit one or both of a buffer status report and traffic pattern information to the radio access network node, transmit assistance information used by the radio access network node to obtain a transmission status of transmission on the second sidelink carrier to the radio access network node, configured as such, wireless terminal. (Appendix 13) The assistance information indicates one or any combination of the size of a transmission resource pool of the second sidelink carrier, the bandwidth of the transmission resource pool, the Channel Busy Ratio (CBR) of the second sidelink carrier, the Sidelink Reference Signal Received Power (SL-RSRP) of the second sidelink carrier, and the Sidelink Channel State Information (SL-CSI) of the second sidelink carrier. The wireless terminal according to Appendix 12. (Appendix 14) The at least one processor is configured to transmit the assistance information using a Radio Resource Control (RRC) message. The wireless terminal according to Appendix 12 or 13. (Appendix 15) The RRC message is a MeasurementReport message, a UEassistanceinformation message, or a SIdelinkUEinformationNR message. The wireless terminal according to Appendix 14. (Appendix 16) The first sidelink carrier belongs to the licensed spectrum of the radio access network node, and the second sidelink carrier belongs to the unlicensed spectrum. The wireless terminal according to any one of Appendices 12 to 15. (Appendix 17) The assistance information is used by the radio access network node to estimate the transmission status of transmission on the second sidelink carrier. The wireless terminal according to any one of Appendices 12 to 16. (Appendix 18) The buffer status report is transmitted to the radio access network node to obtain a dynamic grant for the first sidelink carrier. The traffic pattern information is transmitted to the radio access network node to obtain a configured grant for the first sidelink carrier. The wireless terminal according to any one of Appendices 12 to 17. (Appendix 19) A method performed by a wireless terminal, using a first sidelink carrier to which a first resource allocation mode in which resources are allocated by a radio access network node is applied and a second sidelink carrier to which a second resource allocation mode in which the wireless terminal autonomously selects resources is applied for sidelink communication with a peer wireless terminal, transmitting one or both of a buffer status report and traffic pattern information to the radio access network node, transmitting assistance information used by the radio access network node to obtain a transmission status of transmission on the second sidelink carrier to the radio access network node, comprising the above. (Appendix 20) A program for causing a computer to perform a method for a wireless terminal, wherein the method is A first sidelink carrier to which a first resource allocation mode in which resources are allocated by a radio access network node is applied and a second sidelink carrier to which a second resource allocation mode in which a wireless terminal autonomously selects resources is applied are used for sidelink communication with a peer wireless terminal, transmit one or both of a buffer status report and traffic pattern information to the radio access network node, transmit to the radio access network node assistance information used by the radio access network node to obtain a transmission status of a transmission on the second sidelink carrier, A program comprising the above. (Appendix 21) A radio access network node, at least one memory, at least one processor coupled to the at least one memory, The at least one processor, receives from a wireless terminal one or both of a buffer status report and traffic pattern information regarding a first sidelink carrier to which a first resource allocation mode in which resources are allocated by the radio access network node is applied, receives from the wireless terminal assistance information regarding a second sidelink carrier to which a second resource allocation mode in which the wireless terminal autonomously selects resources is applied, generates one or both of a dynamic grant and a configured grant in consideration of a transmission status of a transmission on the second sidelink carrier obtained based on the assistance information, transmits one or both of the generated dynamic grant and the generated configured grant to the wireless terminal, configured as such, A radio access network node. (Appendix 22) The at least one processor is configured to generate the dynamic grant by reducing the total data volume buffered in the wireless terminal for sidelink transmission to the peer wireless terminal indicated in the buffer status report based on the estimated transmission status of transmission on the second sidelink carrier. The radio access network node according to appendix 21. (Appendix 23) The at least one processor is configured to generate the dynamic grant by excluding the estimated data volume transmissible on the second sidelink carrier from the total data volume buffered in the wireless terminal for sidelink transmission to the peer wireless terminal indicated in the buffer status report. The radio access network node according to appendix 21 or 22. (Appendix 24) The at least one processor is configured to generate the configured grant by excluding the estimated traffic pattern of transmission on the second sidelink carrier from the traffic pattern indicated in the traffic pattern information. The radio access network node according to any one of appendices 21 to 23. (Appendix 25) The traffic pattern information includes one or both of an estimated data arrival periodicity and a maximum transport block size. The radio access network node according to any one of appendices 21 to 24. (Appendix 26) The support information indicates one or any combination of the size of the transmission resource pool of the second sidelink carrier, the bandwidth of the transmission resource pool, the Channel Busy Ratio (CBR) of the second sidelink carrier, the Sidelink Reference Signal Received Power (SL-RSRP) of the second sidelink carrier, and the Sidelink Channel State Information (SL-CSI) of the second sidelink carrier. The radio access network node according to any one of Appendices 21 to 25. (Appendix 27) The at least one processor is configured to receive the support information using a Radio Resource Control (RRC) message. The radio access network node according to any one of Appendices 21 to 26. (Appendix 28) The RRC message is a MeasurementReport message, a UEassistanceinformation message, or a SIdelinkUEinformationNR message. The radio access network node according to Appendix 27. (Appendix 29) The first sidelink carrier belongs to the licensed spectrum of the radio access network node, and the second sidelink carrier belongs to the unlicensed spectrum. The radio access network node according to any one of Appendices 21 to 28. (Appendix 30) The at least one processor is configured to estimate the transmission status of transmission on the second sidelink carrier based on the support information. The radio access network node according to any one of Appendices 21 to 29. (Appendix 31) The buffer status report is transmitted by the wireless terminal to the radio access network node to obtain a dynamic grant for the first sidelink carrier. The traffic pattern information is transmitted by the wireless terminal to the radio access network node to obtain a configured grant for the first sidelink carrier. The radio access network node according to any one of Appendices 21 to 30. (Appendix 32) A method performed by a radio access network node, receiving, from a wireless terminal, one or both of a buffer status report and traffic pattern information regarding a first sidelink carrier to which a first resource allocation mode in which resources are allocated by the radio access network node is applied; receiving, from the wireless terminal, assistance information regarding a second sidelink carrier to which a second resource allocation mode in which the wireless terminal autonomously selects resources is applied; generating one or both of a dynamic grant and a configured grant in consideration of a transmission status on the second sidelink carrier obtained based on the assistance information; transmitting one or both of the generated dynamic grant and the generated configured grant to the wireless terminal. A method comprising the above. (Appendix 33) A program for causing a computer to perform a method for a radio access network node, wherein the method receives, from a wireless terminal, one or both of a buffer status report and traffic pattern information regarding a first sidelink carrier to which a first resource allocation mode in which resources are allocated by the radio access network node is applied; receives, from the wireless terminal, assistance information regarding a second sidelink carrier to which a second resource allocation mode in which the wireless terminal autonomously selects resources is applied; Generate one or both of a dynamic grant and a configured grant in consideration of the transmission status of transmission on the second sidelink carrier obtained based on the support information, Transmit one or both of the generated dynamic grant and the generated configured grant to the wireless terminal, A program comprising the above. (Appendix 34) A wireless terminal, At least one wireless transceiver, At least one processor coupled to the at least one wireless transceiver, The at least one processor, Uses a first sidelink carrier to which a first resource allocation mode in which resources are allocated by a radio access network node is applied and a second sidelink carrier to which a second resource allocation mode in which the wireless terminal autonomously selects resources are applied for sidelink communication with a peer wireless terminal, When there is data to be transmitted and the resources of the second sidelink carrier are also available in the time slot of the first sidelink carrier for which a dynamic grant or a configured grant has been obtained, determine whether to transmit the data on the first sidelink carrier or the second sidelink carrier according to a predetermined rule. Wireless terminal. (Appendix 35) The at least one processor is configured to receive from the radio access network node signaling indicating the predetermined rule or one or more parameters for defining the predetermined rule. The wireless terminal according to Appendix 34. (Appendix 36) If the wireless transceiver can perform sidelink transmission on the first sidelink carrier and sidelink transmission on the second sidelink carrier simultaneously in the time domain, the predetermined rule includes preferentially transmitting the data on the first sidelink carrier. The wireless terminal described in Supplementary Note 34 or 35. (Supplementary Note 37) If there is remaining data that cannot be included in the first transport block transmitted on the first sidelink carrier in the time slot based on the dynamic grant or the configured grant, the predetermined rule includes including the remaining data in the second transport block transmitted on the second sidelink carrier. The wireless terminal described in Supplementary Note 36. (Supplementary Note 38) If the wireless transceiver can perform sidelink transmission on the first sidelink carrier and sidelink transmission on the second sidelink carrier simultaneously in the time domain, the predetermined rule includes selecting the carrier with the lower CBR among the two carriers if the difference between the Channel Busy Ratio (CBR) of the first sidelink carrier and the CBR of the second sidelink carrier exceeds a threshold, and otherwise selecting both carriers. The wireless terminal described in Supplementary Note 34 or 35. (Supplementary Note 39) If the wireless transceiver can perform sidelink transmission on the first sidelink carrier and sidelink transmission on the second sidelink carrier simultaneously in the time domain, the predetermined rule includes selecting the carrier with the better Sidelink Reference Signal Received Power (SL-RSRP) among the two carriers if the difference between the SL-RSRP of the first sidelink carrier and the SL-RSRP of the second sidelink carrier exceeds a threshold, and otherwise selecting both carriers. The wireless terminal described in Supplementary Note 34 or 35. (Supplementary Note 40) If the wireless transceiver can simultaneously perform sidelink transmission on the first sidelink carrier and sidelink transmission on the second sidelink carrier in the time domain, the predetermined rule includes selecting one or both of the first sidelink carrier and the second sidelink carrier whose Channel Busy Ratio (CBR) is lower than a threshold. The wireless terminal according to Appendix 34 or 35. (Appendix 41) If the wireless transceiver can simultaneously perform sidelink transmission on the first sidelink carrier and sidelink transmission on the second sidelink carrier in the time domain, the predetermined rule includes selecting one or both of the first sidelink carrier and the second sidelink carrier whose Sidelink Reference Signal Received Power (SL-RSRP) is better than a threshold. The wireless terminal according to Appendix 34 or 35. (Appendix 42) If the wireless transceiver cannot simultaneously perform sidelink transmission on the first sidelink carrier and sidelink transmission on the second sidelink carrier in the time domain, the predetermined rule includes preferentially transmitting the data on the first sidelink carrier. The wireless terminal according to Appendix 34 or 35. (Appendix 43) If the wireless transceiver cannot simultaneously perform sidelink transmission on the first sidelink carrier and sidelink transmission on the second sidelink carrier in the time domain, the predetermined rule includes selecting the second sidelink carrier if the Channel Busy Ratio (CBR) of the second sidelink carrier is lower than the threshold by more than the CBR of the first sidelink carrier, and otherwise selecting the first sidelink carrier. The wireless terminal according to Appendix 34 or 35. (Appendix 44) If the wireless transceiver cannot simultaneously perform sidelink transmission on the first sidelink carrier and sidelink transmission on the second sidelink carrier in the time domain, the predetermined rule includes selecting the second sidelink carrier if the Sidelink Reference Signal Received Power (SL-RSRP) of the second sidelink carrier may exceed a threshold compared to the SL-RSRP of the first sidelink carrier, and otherwise selecting the first sidelink carrier. The wireless terminal according to Appendix 34 or 35. (Appendix 45) If the wireless transceiver cannot simultaneously perform sidelink transmission on the first sidelink carrier and sidelink transmission on the second sidelink carrier in the time domain, the predetermined rule includes selecting the one of the first sidelink carrier and the second sidelink carrier with a lower Channel Busy Ratio (CBR) than the other. The wireless terminal according to Appendix 34 or 35. (Appendix 46) If the wireless transceiver cannot simultaneously perform sidelink transmission on the first sidelink carrier and sidelink transmission on the second sidelink carrier in the time domain, the predetermined rule includes selecting the one of the first sidelink carrier and the second sidelink carrier with a better Sidelink Reference Signal Received Power (SL-RSRP) than the other. The wireless terminal according to Appendix 34 or 35. (Appendix 47) A method performed by a wireless terminal, using a first sidelink carrier to which a first resource allocation mode in which resources are allocated by a wireless access network node is applied and a second sidelink carrier to which a second resource allocation mode in which the wireless terminal autonomously selects resources is applied for sidelink communication with a peer wireless terminal. When there is data to be transmitted and the resources of the second sidelink carrier are also available in the time slot of the first sidelink carrier for which a dynamic grant or a configured grant has been obtained, determine which of the first sidelink carrier and the second sidelink carrier to transmit the data according to a predetermined rule. A method comprising the above. (Appendix 48) A program for causing a computer to perform a method for a wireless terminal, wherein the method uses a first sidelink carrier to which a first resource allocation mode in which resources are allocated by a radio access network node is applied and a second sidelink carrier to which a second resource allocation mode in which the wireless terminal autonomously selects resources is applied for sidelink communication with a peer wireless terminal, When there is data to be transmitted and the resources of the second sidelink carrier are also available in the time slot of the first sidelink carrier for which a dynamic grant or a configured grant has been obtained, determine which of the first sidelink carrier and the second sidelink carrier to transmit the data according to a predetermined rule. A program comprising the above.

[0164] This application claims priority based on Japanese Patent Application No. 2022-038088 filed on March 11, 2022, and incorporates the entire disclosure thereof herein.

Explanation of Signs

[0165] 1A, 1B UE 2 RAN node 21 Cell 41 AMF 44 PCF 61 V2X application server 103 UE - to - UE direct interface 1503 Baseband processor 1504 Application Processor 1506 Memory 1507 Modules 1604 Processor 1605 Memory 1606 Modules 1702 Processor 1703 Memory 1704 Modules

Claims

1. A wireless terminal, means for using a first sidelink carrier to which a first resource allocation mode in which resources are allocated by a wireless access network node is applied and a second sidelink carrier to which a second resource allocation mode in which the wireless terminal autonomously selects resources is applied for sidelink communication with a peer wireless terminal; means for generating one or both of a buffer status report and traffic pattern information in consideration of a transmission status of transmission on the second sidelink carrier; means for transmitting one or both of the buffer status report and the traffic pattern information to the wireless access network node; comprising a wireless terminal.

2. The generating means is configured to generate the buffer status report by reducing a total data volume buffered in the wireless terminal for transmission to the peer wireless terminal based on a transmission status of transmission on the second sidelink carrier. The wireless terminal according to claim 1.

3. The generating means is configured to generate the buffer status report by excluding an estimated data volume transmissible on the second sidelink carrier from a total data volume buffered in the wireless terminal for transmission to the peer wireless terminal. The wireless terminal according to claim 1 or 2.

4. The generating means is configured to generate the traffic pattern information so as to indicate an estimated traffic pattern of transmission on the first sidelink carrier excluding an estimated traffic pattern of transmission on the second sidelink carrier. The wireless terminal according to claim 1 or 2.

5. The traffic pattern information includes one or both of an estimated data arrival periodicity and a maximum transport block size. The wireless terminal according to claim 1 or 2.

6. The generating means is configured to generate one or both of the buffer status report and the traffic pattern information using a Channel Busy Ratio (CBR) of the second sidelink carrier or a Sidelink Reference Signal Received Power (SL-RSRP) of the second sidelink carrier. The wireless terminal according to claim 1 or 2.

7. The first sidelink carrier belongs to the licensed spectrum of the radio access network node, and the second sidelink carrier belongs to the unlicensed spectrum. The wireless terminal according to claim 1 or 2.

8. The transmission status of the transmission on the second sidelink carrier is the transmission status estimated by the wireless terminal. The wireless terminal according to claim 1 or 2.

9. A method performed by a wireless terminal, comprising: using a first sidelink carrier to which a first resource allocation mode in which resources are allocated by a radio access network node is applied and a second sidelink carrier to which a second resource allocation mode in which the wireless terminal autonomously selects resources is applied for sidelink communication with a peer wireless terminal; generating one or both of a buffer status report and traffic pattern information in consideration of the transmission status of the transmission on the second sidelink carrier; transmitting one or both of the buffer status report and the traffic pattern information to the radio access network node. A method comprising the above.

10. A program for causing a computer to perform a method for a wireless terminal, the method comprising: using a first sidelink carrier to which a first resource allocation mode in which resources are allocated by a radio access network node is applied and a second sidelink carrier to which a second resource allocation mode in which the wireless terminal autonomously selects resources is applied for sidelink communication with a peer wireless terminal; generating one or both of a buffer status report and traffic pattern information in consideration of the transmission status of the transmission on the second sidelink carrier; transmitting one or both of the buffer status report and the traffic pattern information to the radio access network node. A program comprising the above. A program comprising the above.

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