Terminal device, method, and integrated circuit

Abstract

A terminal device according to the present invention communicates with a base station device and transmits a first message to the base station device, the first message including an information element indicating that the terminal device serves as an intermediate relay UE on the basis of a determination that the terminal device serves as the intermediate relay UE.

Description

Terminal device, method, and integrated circuit

[0001] The present invention relates to a terminal device, a method, and an integrated circuit. This application claims priority from Japanese Patent Application No. 2024-221626 filed in Japan on December 18, 2024, the content of which is incorporated herein by reference.

[0002] In the 3rd Generation Partnership Project (3GPP[registered trademark]), which is a standardization project for cellular mobile communication systems, technical studies and standard setting for cellular mobile communication systems, including radio access, core networks, services, etc., are being conducted.

[0003] For example, in 3GPP, E-UTRA (Evolved Universal Terrestrial Radio Access) was started for technical studies and standard setting as a radio access technology (RAT) for cellular mobile communication systems for the 3.9th generation and 4th generation. Even now, in 3GPP, technical studies and standard setting for extended technologies of E-UTRA are being conducted. Note that E-UTRA is also referred to as Long Term Evolution (LTE: registered trademark), and extended technologies may be referred to as LTE-Advanced (LTE-A), LTE-Advanced Pro (LTE-A Pro).

[0004] Also, in 3GPP, NR (New Radio, or NR Radio access) was started for technical studies and standard setting as a radio access technology (RAT) for cellular mobile communication systems for the 5th generation (5G). Even now, in 3GPP, technical studies and standard setting for extended technologies of NR are being conducted.

[0005] 3GPP TS 38.331 v18.2.0, "NR; Radio Resource Control (RRC) protocol specification" pp90-108,pp372-450, pp1493-15163GPP TS 38.300 v18.2.0, "NR; NR and NG-RAN Overall Description" pp50-52,pp166-176, pp187-207

[0006] Within 3GPP, as an extension of NR, a technology called sidelink (SL) is being considered, which allows terminal devices to communicate directly with each other without going through the core network. Furthermore, a technology called UE-to-Network relay (U2N Relay) is being considered, in which a relay terminal device provides sidelink communication, allowing terminal devices to communicate with base station devices via the relay terminal device, and improvements have been made to enhance service continuity in U2N Relay. In addition, consideration has begun for multi-hop relay, which enhances connectivity to remote terminal devices by connecting multiple relay terminal devices.

[0007] One aspect of the present invention has been made in view of the above circumstances, and one of its objectives is to provide a terminal device, a base station device, a method, and an integrated circuit that can efficiently perform communication control.

[0008] To achieve the above objective, one aspect of the present invention employs the following means.

[0009] (1) A first aspect of the present invention is a terminal device that communicates with a base station device, comprising a processing unit and a transmitting unit, wherein the processing unit determines that the terminal device is playing the role of an intermediate relay UE and includes an information element indicating that it is playing the role of an intermediate relay UE in a first message, and the transmitting unit transmits the first message to the base station device.

[0010] (2) A second aspect of the present invention is a method for a terminal device to communicate with a base station device, comprising the steps of: including an information element indicating that the terminal device is playing the role of an intermediate relay UE in a first message, based on the determination that the terminal device is playing the role of an intermediate relay UE; and transmitting the first message to the base station device.

[0011] (3) A third aspect of the present invention is an integrated circuit mounted on a terminal device that communicates with a base station device, which includes a function to include an information element indicating that the terminal device is playing the role of an intermediate relay UE in a first message, based on the terminal device's determination to play the role of an intermediate relay UE, and a function to transmit the first message to the base station device.

[0012] These comprehensive or specific embodiments may be implemented as systems, devices, methods, integrated circuits, computer programs, or recording media, or as any combination of systems, devices, methods, integrated circuits, computer programs, and recording media.

[0013] According to one aspect of the present invention, it is possible to provide a terminal device, a base station device, and a method for realizing efficient communication control processing.

[0014] A schematic diagram of the communication system according to this embodiment. A diagram showing an example of the protocol configuration in NR sidelink communication according to this embodiment. A diagram showing an example of the protocol configuration in NR sidelink communication according to this embodiment. A diagram showing an example of the protocol configuration in the discovery procedure according to this embodiment. A block diagram showing the configuration of the terminal device according to this embodiment. A block diagram showing the configuration of the base station device according to this embodiment. A diagram showing an example of the protocol configuration in NR according to this embodiment. A diagram showing an example of the protocol configuration of the control plane of the L2 U2N relay according to this embodiment. A diagram showing an example of the protocol configuration of the user plane of the L2 U2N relay according to this embodiment. An example of processing according to this embodiment. A diagram showing an example of the protocol configuration of the control plane of the multi-hop L2 U2N relay according to this embodiment.

[0015] This embodiment will now be described in detail with reference to the drawings.

[0016] In this embodiment, the names of each node and entity, and the processing at each node and entity, are described when the wireless access technology is NR, but this embodiment may be applied to other wireless access technologies. The names of each node and entity in this embodiment may be different.

[0017] Figure 1 is a schematic diagram of the communication system according to this embodiment. The functions of each node, wireless access technology, core network, interface, etc., described using Figure 1 are only some of the functions closely related to this embodiment, and other functions may also be present.

[0018] E-UTRA may be a wireless access technology. E-UTRA may also be an air interface between UE122 and ng-eNB100. The air interface 112 between UE122 and ng-eNB100 may be called the Uu interface. ng-eNB (ng E-UTRAN Node B)100 may be the base station equipment for E-UTRAN. ng-eNB100 may have the E-UTRA protocol described below. The E-UTRA protocol may consist of the E-UTRA User Plane (UP) protocol and the E-UTRA Control Plane (CP) protocol described below. ng-eNB100 may terminate the E-UTRA User Plane protocol and the E-UTRA Control Plane protocol to UE122. The wireless access network composed of eNBs may be called E-UTRAN.

[0019] NR may be a wireless access technology. NR may also be an air interface between UE122 and gNB102. The air interface 112 between UE122 and gNB102 may be called the Uu interface. gNB (g Node B) 102 may be the base station equipment for NR. gNB102 may have the NR protocol described below. The NR protocol may consist of the NR User Plane (UP) protocol and the NR Control Plane (CP) protocol described below. gNB102 may terminate the NR User Plane protocol and the NR Control Plane protocol to UE122.

[0020] The interface 110 between ng-eNB100 and gNB102 may be called the Xn interface. Furthermore, ng-eNB and gNB may be connected to 5GC via an interface called the NG interface (not shown). 5GC may be the core network. One or more base station devices may be connected to 5GC via the NG interface.

[0021] The state in which a base station device can be connected only via the Uu interface may be called Inside NG-RAN Coverage or In-Coverage (IC). Conversely, the state in which a base station device cannot be connected only via the Uu interface may be called Outside NG-RAN Coverage or Out-of-Coverage (OoC). The air interface 114 between UE122s may be called the PC5 interface. Communication between UE122s conducted via the PC5 interface may be called sidelink (SL) communication. Furthermore, a terminal device capable of performing sidelink communication may be called a sidelink-capable terminal device.

[0022] In the following description, ng-eNB100 and / or gNB102 will also be simply referred to as base station equipment, and UE122 will also be simply referred to as terminal equipment or UE. Furthermore, the PC5 interface will be simply referred to as PC5, and the Uu interface will be simply referred to as Uu.

[0023] Sidelink is a technology that enables direct communication between terminal devices via PC5, and sidelink transmission and reception on PC5 take place both inside and outside the NG-RAN coverage.

[0024] NR SL communication has three transmission modes, and SL communication is performed using a pair of Source Layer-2 (L2) IDs and Destination Layer-2 (L2) IDs in one of the transmission modes. The Source Layer-2 ID and Destination Layer-2 ID may also be referred to as Source L2ID and Destination L2ID, respectively. The three transmission modes are "Unicast transmission," "Groupcast transmission," and "Broadcast transmission." The transmission mode may also be referred to as Cast type, etc. Unicast transmission for direct communication is supported on PC5, and a PC5 unicast link between two UEs may be established for direct communication. Furthermore, the PC5 unicast link may be maintained, modified, or released according to the requirements or communication requirements of the application layer.

[0025] Unicast transmission is characterized by (1) support for a single PC5-RRC connection with a paired UE, (2) transmission and reception of control information and user traffic between UEs on the sidelink, (3) support for sidelink HARQ feedback, (4) transmit power control on the sidelink, (5) support for RLC AM, and (6) detection of radio link failure for the PC5-RRC connection.

[0026] Furthermore, groupcast transmission is characterized by (1) sending and receiving user traffic between UEs belonging to a group of sidelinks, and (2) support for sidelink HARQ feedback.

[0027] Furthermore, broadcast transmission is characterized by (1) sending and receiving user traffic between sidelink UEs.

[0028] Figures 2 and 3 show an example of the protocol architecture in NR sidelink communication according to this embodiment. The functions of each protocol described using Figures 2 and / or 3 are some of the functions closely related to this embodiment, and other functions may be present. In this embodiment, the sidelink (SL) may be a link between terminal devices.

[0029] Figure 2(A) is a diagram of the protocol stack of the control plane (CP) for SCCH using RRC, configured on the PC5 interface. As shown in Figure 2(A), the control plane protocol stack for SCCH using RRC may consist of the radio physical layer (PHY) 200, the medium access control layer (MAC) 202, the radio link control layer (RLC) 204, the packet data convergence protocol layer (PDCP) 206, and the radio resource control layer (RRC) 208. Figure 2(B) is a diagram of the protocol stack of the control plane for SCCH using PC5-S, configured on the PC5 interface. As shown in Figure 2(B), the control plane protocol stack for SCCH using PC5-S may consist of a radio physical layer (PHY) 200, a medium access control layer (MAC) 202, a radio link control layer (RLC) 204, a packet data convergence protocol layer (PDCP) 206, and a PC5 signaling layer (PC5-S) 210.

[0030] Figure 3(A) is a diagram of the control plane protocol stack for SBCCH configured on the PC5 interface. As shown in Figure 3(A), the control plane protocol stack for SBCCH may consist of a radio physical layer (PHY) 200, a medium access control layer (MAC) 202, a radio link control layer (RLC) 204, and a radio resource control layer (RRC) 208. Figure 3(B) is a diagram of the user plane (UP) protocol stack for STCH configured on the PC5 interface. As shown in Figure 3(B), the control plane protocol stack for STCH may consist of a PHY (Physical layer) 200, a MAC (Medium Access Control) 202, a Radio Link Control (RLC) 204, a Packet Data Convergence Protocol (PDCP) 206, and a Service Data Adaptation Protocol (SDAP) 310.

[0031] The AS (Access Stratum) layer may include some or all of PHY200, MAC202, RLC204, PDCP206, SDAP310, and RRC208. Furthermore, PC5-S210 and Discovery400 (described later) may be layers above the AS layer.

[0032] In this embodiment, the terms PHY (PHY layer), MAC (MAC layer), RLC (RLC layer), PDCP (PDCP layer), SDAP (SDAP layer), RRC (RRC layer), and PC5-S (PC5-S layer) may be used. In this case, PHY (PHY layer), MAC (MAC layer), RLC (RLC layer), PDCP (PDCP layer), SDAP (SDAP layer), RRC (RRC layer), and PC5-S (PC5-S layer) may be the PHY (PHY layer), MAC (MAC layer), RLC (RLC layer), PDCP (PDCP layer), SDAP (SDAP layer), RRC (RRC layer), and PC5-S (PC5-S layer) of the NR sidelink protocol, respectively. Note that when performing sidelink communication using E-UTRA technology, the SDAP layer may be omitted. Furthermore, to clearly indicate that a protocol is for sidelinking, for example, RLC may be expressed as sidelink RLC, and other protocols may also be indicated as sidelinking protocols by adding "sidelink," "SL," or "PC5" to their names.

[0033] Furthermore, in this embodiment, when distinguishing between the E-UTRA protocol and the NR protocol, PHY, MAC, RLC, PDCP, and RRC may be referred to as E-UTRA PHY or LTE PHY, E-UTRA MAC or LTE MAC, E-UTRA RLC or LTE RLC, E-UTRA PDCP or LTE PDCP, and E-UTRA RRC or LTE RRC, respectively. Also, PHY, MAC, RLC, PDCP, and RRC may be described as E-UTRA PHY or LTE PHY, E-UTRA MAC or LTE MAC, E-UTRA RLC or LTE RLC, E-UTRA PDCP or LTE PDCP, and E-UTRA RRC or LTE RRC, respectively. Furthermore, when distinguishing between the E-UTRA protocol, the sidelink protocol, and the NR protocol, PHY, MAC, RLC, PDCP, and RRC may be referred to as NR PHY, NR MAC, NR RLC, NR RLC, and NR RRC, respectively. Additionally, PHY, MAC, RLC, PDCP, and RRC may sometimes be written as NR PHY, NR MAC, NR RLC, NR PDCP, and NR RRC, respectively.

[0034] This section describes entities in the AS layer of E-UTRA, NR, and / or Sidelink. Entities that possess some or all of the functions of the physical layer may be called PHY entities. Entities that possess some or all of the functions of the MAC layer may be called MAC entities. Entities that possess some or all of the functions of the RLC layer may be called RLC entities. Entities that possess some or all of the functions of the PDCP layer may be called PDCP entities. Entities that possess some or all of the functions of the SDAP layer may be called SDAP entities. Entities that possess some or all of the functions of the RRC layer may be called RRC entities. PHY entities, MAC entities, RLC entities, PDCP entities, SDAP entities, and RRC entities may be replaced with PHY, MAC, RLC, PDCP, SDAP, and RRC, respectively. Furthermore, each entity in the AS layer may be a common entity in E-UTRA, NR, and / or Sidelink, or it may be an independent entity.

[0035] Furthermore, the data provided from MAC, RLC, PDCP, and SDAP to lower layers, and / or the data provided from lower layers to MAC, RLC, PDCP, and SDAP, may be referred to as MAC PDU (Protocol Data Unit), RLC PDU, PDCP PDU, and SDAP PDU, respectively. Also, the data provided from higher layers to MAC, RLC, PDCP, and SDAP, and / or the data provided from MAC, RLC, PDCP, and SDAP to higher layers, may be referred to as MAC SDU (Service Data Unit), RLC SDU, PDCP SDU, and SDAP SDU, respectively. In addition, a segmented RLC SDU may be referred to as an RLC SDU segment.

[0036] Here, the base station device and the terminal device exchange (send and receive) signals at the higher layer over the Uu interface. The higher layer may also be called the upper layer, and they are interchangeable. For example, the base station device and the terminal device may send and receive RRC messages (also called RRC message or RRC signalling) at the Radio Resource Control (RRC) layer. The base station device and the terminal device may also send and receive MAC control elements (MAC CE) at the MAC (Medium Access Control) layer. Furthermore, the RRC layer of the terminal device acquires system information broadcast from the base station device. Here, RRC messages, system information, and / or MAC control elements are also called higher layer signals (higher layer signaling) or higher layer parameters (higher layer parameters). Each of the parameters included in the higher layer signal received by the terminal device may also be called a higher layer parameter. For example, in the processing of the PHY layer, the upper layer refers to the layer above the PHY layer, and may refer to one or more of the MAC layer, RRC layer, RLC layer, PDCP layer, NAS (Non-Access Stratum) layer, etc. For example, in the processing of the MAC layer, the upper layer may refer to one or more of the RRC layer, RLC layer, PDCP layer, NAS layer, etc.

[0037] Furthermore, terminal devices also exchange signals (send and receive) at the higher layer over the PC5 interface. Terminal devices may also send and receive RRC messages (also called RRC signallings) at the Radio Resource Control (RRC) layer. In addition, terminal devices may send and receive MAC control elements (MAC CEs) at the MAC (Medium Access Control) layer. Here, RRC messages and / or MAC control elements are also called higher layer signals (higher layer signaling) or higher layer parameters (higher layer parameters). Each parameter included in the higher layer signal received by a terminal device may also be called a higher layer parameter. For example, in the processing of the PHY layer, the higher layer refers to the layer above the PHY layer, and may refer to one or more of the MAC layer, RRC layer, RLC layer, PDCP layer, PC5-S layer, Discovery layer, etc. For example, in MAC layer processing, the upper layers may refer to one or more of the RRC layer, RLC layer, PDCP layer, PC5-S layer, Discovery layer, etc.

[0038] In the following, the phrases "A is provided in the upper layer" or "A is provided by the upper layer" may mean that the upper layer of a terminal device (mainly the RRC layer or MAC layer, etc.) receives A from a base station device or other terminal device, and that received A is provided from the upper layer of the terminal device to the physical layer of the terminal device. For example, "being provided with upper layer parameters" in a terminal device may mean that the terminal device receives an upper layer signal from a base station device or other terminal device, and the upper layer parameters contained in the received upper layer signal are provided from the upper layer of the terminal device to the physical layer of the terminal device. Setting upper layer parameters in a terminal device may mean that the terminal device is provided with upper layer parameters. For example, setting upper layer parameters in a terminal device may mean that the terminal device receives an upper layer signal from a base station device or other terminal device and sets the received upper layer parameters in the upper layer. However, setting upper layer parameters in a terminal device may also include setting default parameters that are pre-assigned to the upper layer of the terminal device. When describing the transmission of RRC messages from a terminal device to a base station device or other terminal devices, the expression "submitting a message from the terminal device's RRC entity to a lower layer" may be used. In a terminal device, "submitting a message to a lower layer" from the RRC entity may mean submitting a message to the PDCP layer. In a terminal device, "submitting a message to a lower layer" from the RRC layer may mean submitting to the PDCP entity corresponding to each SRB (SRB0, SRB1, SRB2, SRB3, etc.), since RRC messages are transmitted using SRBs. When the terminal device's RRC entity receives an indication from a lower layer, that lower layer may mean one or more layers such as the PHY layer, MAC layer, RLC layer, PDCP layer, etc.

[0039] An example of the functions of the PHY will be described. The PHY of a terminal device may have the function of transmitting and receiving data transmitted via a sidelink (SL) physical channel with the PHY of another terminal device. The PHY may be connected to the upper-layer MAC via a transport channel. The PHY may deliver data to the MAC via the transport channel. Also, the PHY may be provided with data from the MAC via the transport channel. In the PHY, a Radio Network Temporary Identifier (RNTI) may be used to identify various control information.

[0040] Here, the physical channel will be described. The physical channels used for wireless communication between a terminal device and another terminal device may include the following physical channels.

[0041] Physical Sidelink Broadcast CHannel (PSBCH) Physical Sidelink Control CHannel (PSCCH) Physical Sidelink Shared CHannel (PSSCH) Physical Sidelink Feedback CHannel (PSFCH)

[0042] The PSBCH may be used to notify the system information required by the terminal device.

[0043] The PSCCH may be used to indicate resources and other transmission parameters related to the PSSCH.

[0044] The PSSCH may be used to transmit data and control information related to HARQ / CSI feedback to another terminal device.

[0045] The PSFCH may be used to carry HARQ feedback to another terminal device.

[0046] This section describes an example of MAC functionality. MAC may also be called a MAC sublayer. MAC may have the functionality to map various logical channels to corresponding transport channels. Logical channels may be identified by a Logical Channel Identity (Logical Channel ID). MAC may be connected to the higher-level RLC via logical channels. Logical channels may be divided into control channels that transmit control information and traffic channels that transmit user information, depending on the type of information being transmitted. MAC may have the functionality to multiplex MAC SDUs belonging to one or more different logical channels and provide them to the PHY. MAC may also have the functionality to demultiplex MAC PDUs provided from the PHY and provide them to the higher layer via the logical channel to which each MAC SDU belongs. MAC may also have the functionality to perform error correction through HARQ (Hybrid Automatic Repeat reQuest). MAC may also have the functionality to report scheduling information. MAC may have the functionality to prioritize between terminal devices using dynamic scheduling. MAC may also have the functionality to prioritize between logical channels within a single terminal device. MAC may also have the functionality to prioritize overlapping resources within a single terminal device. E-UTRA MAC may have the functionality to identify Multimedia Broadcast Multicast Services (MBMS). NR MAC may also have the functionality to identify Multicast Broadcast Service (MBS). MAC may have the functionality to select the transport format.The MAC may have functions such as discontinuous reception (DRX) and / or discontinuous transmission (DTX), a function to execute a random access (RA) procedure, a power headroom report (PHR) function to notify information on transmit power, a buffer status report (BSR) function to notify the data volume information of a transmit buffer, etc. The NR MAC may have a bandwidth adaptation (BA) function. Also, the MAC PDU format used in E-UTRA MAC and the MAC PDU format used in NR MAC may be different. Further, the MAC PDU may include a MAC control element (MAC CE), which is an element for control in the MAC.

[0047] Further, on the PC5 interface, the MAC sublayer may additionally provide services and functions such as radio resource selection to select radio resources for sidelink transmission, filtering of packets received in sidelink communication, prioritization between the uplink and sidelink, reporting of sidelink channel state information (Sidelink CSI), etc.

[0048] The mapping between the logical channel for sidelink (SL) used in E-UTRA and / or NR and the logical channel for sidelink and the transport channel will be described.

[0049] The SBCCH (Sidelink Broadcast Control Channel) may be a logical channel for sidelink for notifying sidelink system information from one terminal device to one or more terminal devices. Also, the SBCCH may be mapped to the SL-BCH, which is a sidelink transport channel.

[0050] SCCH (Sidelink Control Channel) may be a logical channel for sidelinks used to transmit control information, such as PC5-RRC messages and PC5-S messages, from one terminal device to one or more terminal devices. SCCH may also be mapped to SL-SCH, which is a sidelink transport channel.

[0051] STCH (Sidelink Traffic Control Channel) may be a logical channel for sidelinks used to transmit user information from one terminal device to one or more terminal devices. STCH may also be mapped to SL-SCH, which is a sidelink transport channel.

[0052] An example of RLC functionality is described below. RLC may also be called an RLC sublayer. E-UTRA RLC may have the functionality to segment and / or concatenate data provided from the upper layer PDCP and provide it to the lower layer. E-UTRA RLC may have the functionality to reassemble and reorder data provided from the lower layer and provide it to the upper layer. NR RLC may have the functionality to add a sequence number to data provided from the upper layer PDCP that is independent of the sequence number added by the PDCP. NR RLC may also have the functionality to segment the data provided from the PDCP and provide it to the lower layer. NR RLC may also have the functionality to reassemble data provided from the lower layer and provide it to the upper layer. RLC may also have a data retransmission function and / or an automatic repeat request function (ARQ). RLC may also have a function to perform error correction using ARQ. The control information sent from the receiver to the transmitter of RLC to perform ARQ, indicating data that needs to be retransmitted, may be called a status report. The instruction to send a status report sent from the transmitter to the receiver of RLC may be called a poll. RLC may also have a function to detect data duplication. RLC may also have a function to discard data. RLC may have three modes: Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode (AM). In TM, data received from the upper layer is not split, and an RLC header does not need to be added. A TM RLC entity is a unidirectional entity and may be configured as a transmitting TM RLC entity or a receiving TM RLC entity.UM performs tasks such as splitting and / or combining data received from higher layers and adding RLC headers, but does not need to control data retransmission. UM RLC entities may be unidirectional or bidirectional. If a UM RLC entity is unidirectional, it may be configured as a transmitting UM RLC entity or a receiving UM RLC entity. If a UM RLC entity is bidirectional, it may be configured as a UM RLC entity consisting of a transmitting side and a receiving side. AM may perform tasks such as splitting and / or combining data received from higher layers, adding RLC headers, and controlling data retransmission. AM RLC entities are bidirectional entities and may be configured as AM RLCs consisting of a transmitting side and a receiving side. Data provided to lower layers by TM, and / or data provided by lower layers, may be called TMD PDUs. Similarly, data provided to lower layers by UM, and / or data provided by lower layers, may be called UMD PDUs. Furthermore, data provided to lower layers by AM, or data provided by lower layers, may be called AMD PDUs. The RLC PDU format used in E-UTRA RLC and the RLC PDU format used in NR RLC may be different. Also, there may be data RLC PDUs and control RLC PDUs. Data RLC PDUs may be called RLC DATA PDUs (RLC Data PDUs). Control RLC PDUs may be called RLC CONTROL PDUs (RLC Control PDUs). Note that control RLC PDUs used to send status reports may be called status PDUs (STATUS PDUs).

[0053] In sidelinking, TM may be used for SBCCH, UM only is used for groupcast and broadcast transmissions, and UM and AM can be used for unicast transmissions. Furthermore, in sidelinking, UM for groupcast and broadcast transmissions supports unidirectional transmission only.

[0054] This section describes some examples of PDCP functionality. PDCP may be referred to as the PDCP sublayer. PDCP may have a function for maintaining sequence numbers. PDCP may also have a header compression / decompression function for efficiently transmitting user data such as IP packets and Ethernet frames over the wireless section. The protocol used for compressing and decompressing IP packet headers may be called the ROHC (Robust Header Compression) protocol. The protocol used for compressing and decompressing Ethernet frame headers may be called the EHC (Ethernet® Header Compression) protocol. PDCP may also have data encryption / decryption functions. PDCP may also have data integrity protection and integrity verification functions. PDCP may also have a re-ordering function. PDCP may also have a PDCP SDU retransmission function. PDCP may also have a data discard function using a discard timer. PDCP may also have a duplication function. PDCP may also have a function to discard duplicate received data. A PDCP entity is a bidirectional entity and may consist of a transmitting PDCP entity and a receiving PDCP entity. The PDCP PDU format used in E-UTRA PDCP and the PDCP PDU format used in NR PDCP may be different. Furthermore, there may be data PDCP PDUs and control PDCP PDUs. The data PDCP PDU may be called a PDCP DATA PDU (PDCP Data PDU). The control PDCP PDU may be called a PDCP CONTROL PDU (PDCP Control PDU).

[0055] Regarding sidelink, the following limitations exist regarding PDCP functionality and services: (1) Out-of-order delivery may only be supported via unicast transmission. (2) Duplication on the PC5 interface is not supported.

[0056] This section describes an example of SDAP functionality. SDAP is a Service Data Adaptive Protocol Layer (SPD). In a sidelink, SDAP may have the function of mapping the sidelink QoS flow (PC5 QoS flow) sent from one terminal device to another with the sidelink data radio bearer (DRB). SDAP may also have the function of storing mapping rule information. Furthermore, SDAP may have the function of marking QoS flow identifiers (QoS Flow ID: QFI) and PC5 QoS flow identifiers (PC5 QoS Flow ID: PQFI or PFI). Note that there may be data SDAP PDUs and control SDAP PDUs. The data SDAP PDU may be called an SDAP DATA PDU (SDAP Data PDU). The control SDAP PDU may be called an SDAP CONTROL PDU (SDAP Control PDU). In sidelinks, there may be one SDAP entity for each destination for any of the unicast, groupcast, or broadcast transmissions associated with that destination. Furthermore, reflective QoS is not supported on the PC5 interface.

[0057] An example of RRC functionality is described below. RRC may support services and functions on the PC5 interface such as forwarding PC5-RRC messages between peer UEs, maintaining and releasing PC5-RRC connections between two UEs, and detecting sidelink radio link failures for PC5-RRC connections. A PC5-RRC connection is a logical connection between two UEs corresponding to a source L2ID and destination L2ID pair, and is considered established after the corresponding PC5 unicast link has been established. There is a one-to-one correspondence between PC5-RRC connections and PC5 unicast links. A UE may have multiple PC5-RRC connections for one or more UEs for different pairs of source L2ID and destination L2ID. Individual PC5-RRC procedures and messages may be used by a UE to forward UE capability and sidelink configuration to a peer UE. Both peer UEs may also exchange their UE capability and sidelink configuration with each other using individual bidirectional procedures. The UE releases the PC5-RRC connection if it is not interested in sidelink transmission, if a sidelink wireless link failure is detected for the PC5-RRC connection, and if the Layer 2 link release procedure is completed.

[0058] A UE performing a sidelink transmission may transmit a PSCCH and a PSSCH in association. Sidelink transmission may involve transmitting a signal and / or data (message) via a physical channel for sidelinks (PSBCH, PSSCH, PSCCH, etc.), and sidelink reception may involve receiving a signal and / or data (message) via a physical channel for sidelinks. Communication using sidelink transmission and reception may also be referred to as sidelink communication. The UE may recognize the data (message) based on the signal. Each PSSCH transmission may be associated with a certain PSCCH (a PSCCH) transmission. A PSCCH transmission carries a first SCI (1st stage of the SCI) associated with the PSSCH transmission, and a second SCI (2nd stage of the SCI) may be carried within the resources of the PSSCH (the PSSCH). A PSCCH transmission may include the first SCI, and a PSSCH transmission may include the second SCI. Furthermore, PSCCH transmissions and PSSCH transmissions may be referred to as sidelink transmissions, and SCI may be Sidelink Control Information. The first SCI may contain information in a format called SCI format 1-A and may be used for scheduling the PSSCH and the second SCI on the PSSCH. SCI format 1-A may contain information such as data priority, frequency and time resources on which the PSSCH is transmitted, resource reservation period, DMRS arrangement pattern, format of the second SCI, beta offset indication value, number of DMRS ports, and information indicating the modulation and coding scheme, and may also contain other information. Furthermore, the SCI carried on the PSSCH may be the second SCI, and the second SCI may transport sidelink scheduling information and / or inter-UE coordination related information. The second SCI may contain information in a format referred to as SCI Format 2-A, SCI Format 2-B, or SCI Format 2-C, etc.SCI formats 2-A, 2-B, and 2-C may include information such as HARQ process-related information, information indicating whether the data is new, redundancy version, source ID identifying the source UE, destination ID identifying the destination UE, and information indicating whether HARQ feedback is possible. SCI format 2-A may also include information indicating the cast type and information indicating whether Channel State Information (CSI) is requested. SCI format 2-B may also include an identifier indicating the zone and request information regarding the communication range. SCI format 2-C may also include information indicating whether Channel State Information is requested and information indicating whether inter-UE coordination information is provided or requested. If SCI format 2-C includes information providing inter-UE coordination information, it may also include information indicating the resource combination, information indicating the initial resource location, reference slot location information, information indicating the type of resource set, the lowest subchannel index, and so on. If SCI format 2-C includes information requesting inter-UE coordination information, SCI format 2-C may also include additional information such as priority, number of subchannels, resource reservation interval, resource selection window position, and resource set type. Note that each SCI format may also include information other than that described above.

[0059] Next, we will describe the procedure for a UE receiving a PSSCH. When the UE detects SCI format 1-A on a PSCCH, it can decode the PSSCH according to the detected SCI format 2-A or SCI format 2-B, and the associated PSSCH resource settings configured by the upper layer. Note that the UE does not need to decode more than one PSCCH for each candidate PSCCH resource. Also, if the UE does not support the modulation and coding scheme shown in SCI format 1-A, it does not need to decode the corresponding SCI format 2-A and SCI format 2-B, and the PSSCH associated with SCI format 1-A.

[0060] Furthermore, if the parameter indicating whether the DMRS used for L1 RSRP measurement during sensing operations in the upper (RRC) layer is the DMRS for PSCCH or the DMRS for PSSCH is set to PSSCH, the UE may measure the PSSCH RSRP from the DMRS resource element for PSSCH associated with the received SCI format 1-A. If PSCCH is set, the UE may measure the PSCCH RSRP from the DMRS resource element for PSCCH associated with the received SCI format 1-A.

[0061] Terminal devices capable of sidelink communication may perform discovery. There may be two types of discovery: Model A and Model B. Figure 4 shows the protocol stack in the discovery procedure. Mode A uses a single discovery protocol message, while Model B may use two discovery protocol messages. The single discovery protocol message in Model A may be an announcement message, while the discovery protocol messages in Model B may be a solicitation message and a response message. Note that the announcement message, solicitation message, and response message may be collectively referred to as discovery messages, and other messages with different names used in the discovery procedure may also be referred to as discovery messages. The following outlines the procedures for Model A and Model B in ProSe Direct Discovery.

[0062] In Model A, the UE that sends an announcement message may be called the Announcing UE, and the UE that monitors the announcement message may be called the Monitoring UE. The announcement message may include information such as the type of discovery message, ProSe Application Code or ProSe Restricted Code, and security protection element, and may also include additional metadata information. The announcement message is sent using the Destination L2ID (Destination Layer-2 ID) and Source L2ID (Source Layer-2 ID), and the Monitoring UE determines the Destination L2ID in order to receive the announcement message. The Destination L2ID may be the Layer-2 identifier of the Destination UE, and the Source L2ID may be the Layer-2 identifier of the Source UE. The Destination UE may simply be referred to as the Destination.

[0063] In Model B, the UE that sends a solicitation message may be called the discoverer UE, and the UE that receives the solicitation message, and / or sends a response message to the discoverer UE, may be called the discoveree UE. The solicitation message may include information such as the type of discovery message, ProSe Query Code, and security protection elements. The solicitation message is sent using the destination L2ID and source L2ID, and the discoveree UE determines the destination L2ID to receive the solicitation message. Also, a discoveree UE that responds to a solicitation message sends a response message. The response message may include information such as the type of discovery message, ProSe Response Code, and security protection elements, and may also include additional metadata information. The response message is sent using the source L2ID, and the destination L2ID is set to the source L2ID of the received solicitation message.

[0064] Discovery may include types other than ProSe Direct Discovery, which discovers other UEs for direct communication with other UEs. Other types may include Group Member Discovery, which discovers one or more UEs for communication within a group using sidelinks, and 5G ProSe UE-to-Network Relay Discovery, which discovers candidate relay UEs for connecting to the network via relay UEs. The above-mentioned discovery is an example of discovery provided by an application called ProSe, but there may be other types of discovery depending on the application or service performing sidelink communication. Furthermore, the information included in the discovery protocol message may differ depending on the type of discovery, and additional messages may be sent to transmit additional information.

[0065] Figure 4 is a diagram of an example of a protocol configuration including the discovery protocol according to this embodiment. As shown in Figure 4, the discovery plane protocol stack, including the discovery protocol, may consist of a PHY (Physical layer) 200, which is the radio physical layer; a MAC (Medium Access Control) 202, which is the medium access control layer; an RLC (Radio Link Control) 204, which is the radio link control layer; a PDCP (Packet Data Convergence Protocol) 206, which is the packet data convergence protocol layer; and a Discovery 400, which is the discovery protocol layer. Discovery 400 may be a protocol used to process discovery procedures. The interface between UEs performing discovery may be referred to as PC5-D.

[0066] Multiple resource pools may be configured for sending messages used in discovery procedures (discovery messages), and one or more resource pools may be configured specifically for discovery. If a resource pool dedicated to discovery is configured, the UE may use the resource pool dedicated to discovery for sending discovery messages. If a resource pool dedicated to discovery is not configured, the UE may use the resource pool for sidelink communication for sending discovery messages. Note that multiple resource pools for sidelink communication and resource pools dedicated to discovery may be configured simultaneously. Each resource pool may be configured in UE-specific signaling or may be configured in advance.

[0067] The Direct Communication Request (DCR) message is also described. A Direct Communication Request message may be a message used to establish a unicast link. A DCR message may include at least the identifier of the source UE, and may also include the identifier of the target UE if the target UE identifier is provided by the application layer, as well as other information, such as security information or application information. A DCR message may also be transmitted by unicast or broadcast using the source L2ID and destination L2ID. Discovery messages and DCR messages may also be sidelink transmitted messages. A discovery message may also be integrated into a DCR message. If an integrated discovery message is used for a U2N relay or U2U relay, the DCR message may additionally include information indicating that it is a relay message (relay_indication), for example.

[0068] In each unicast PC5-RRC connection, a sidelink signaling radio bearer (SRB) may be configured. A sidelink SRB used to transmit PC5-S messages before PC5-S security is established may be referred to as SL-SRB0. A sidelink SRB used to transmit PC5-S messages to establish PC5-S security may be referred to as SL-SRB1. A sidelink SRB used to transmit protected PC5-S messages after PC5-S security is established may be referred to as SL-SRB2. A sidelink SRB used to transmit protected PC5-RRC signaling after PC5-S security is established may be referred to as SL-SRB3. A sidelink SRB used to transmit and / or receive discovery messages in NR may be referred to as SL-SRB4. Note that PC5-RRC signaling may be RRC signaling between UEs transmitted and received on PC5. PC5-RRC signaling may also be referred to as PC5-RRC messages.

[0069] Here, we will explain UE-to-Network (U2N) relays. A U2N relay may be a function that provides network connectivity to a remote terminal device (Remote UE). A remote terminal device that connects to the network using a U2N relay may be called a U2N Remote UE. A terminal device that provides network connectivity to a U2N Remote UE may be called a U2N relay terminal device (Relay UE), or simply a relay terminal device (Relay UE). A U2N Relay UE may use a Uu interface for communication with a base station device, or a PC5 interface for communication with a U2N Remote UE. Furthermore, there may be different types of U2N relays, such as Layer 2 (L2) U2N relays and Layer 3 (L3) U2N relays. A remote terminal device in an L2 U2N relay may be specifically called an L2 U2N Remote UE, and a relay terminal device in an L2 U2N relay may be specifically called an L2 U2N Relay UE. Furthermore, in an L2 U2N relay, a Sidelink Relay Adaptation Protocol (SRAP) layer, SRAP (SRAP layer) 800, may be present. Note that SRAP800 may simply be referred to as SRAP.

[0070] Figure 8 is a diagram showing an example of the protocol configuration of the control plane (C-plane) of an L2 U2N relay, including the SRAP layer (SRAP800) according to this embodiment. Figure 9 is a diagram showing an example of the protocol configuration of the user plane (U-plane) of an L2 U2N relay, including the SRAP layer according to this embodiment. As shown in Figures 8 and 9, the SRAP layer may be associated between the Remote UE and the Relay UE, or between the Relay UE and the gNB102. Note that the gNB102 shown in Figures 8 and 9 may be the ng-eNB100. The Remote UE or Relay UE may be the UE122. The Relay UE may also have the same configuration as the UE122.

[0071] The SRAP layer is described below. The SRAP layer may also be called the SRAP sublayer or simply SRAP. The SRAP sublayer may reside above the RLC sublayer for both the control plane and user plane of the PC5 interface and the Uu interface. The SRAP sublayer on PC5 may be used for bearer mapping purposes. In an L2 U2N Relay UE, the SRAP sublayer may contain one SRAP entity on the Uu interface and a separately collocated SRAP entity on the PC5 interface. In an L2 U2N Remote UE, the SRAP sublayer may contain only one SRAP entity on the PC5 interface. An SRAP entity associated between the Remote UE and the Relay UE via the PC5 interface may be specifically called PC5-SRAP, and an SRAP entity associated between the Relay UE and the gNB via Uu may be specifically called Uu-SRAP. Furthermore, when clarifying interface names, other entities may also be expressed in the same format as SRAP, such as (interface name)-(entity name). Each SRAP entity may have a transmitter and a receiver. On the PC5 interface, the transmitter of an L2 U2N Remote UE SRAP entity may be associated with the receiver of an L2 U2N Relay UE SRAP entity, and the receiver of an L2 U2N Remote UE SRAP entity may be associated with the transmitter of an L2 U2N Relay UE SRAP entity. Also, on the Uu interface, the transmitter of an L2 U2N Relay UE SRAP entity may be associated with the receiver of an SRAP entity of gNB102, and the receiver of an L2 U2N Relay UE SRAP entity may be associated with the transmitter of an SRAP entity of gNB102.

[0072] Furthermore, an SRAP entity may have functions for transferring data, determining the UE ID field and bearer ID field of the SRAP header to be attached to the data packet, determining the egress link, and determining the egress RLC channel.

[0073] Furthermore, in Figures 8 and 9, a PC5 Relay RLC channel may be set between the Remote UE and the Relay UE, and a Uu Relay RLC channel may be set between the Relay UE and the gNB102.

[0074] This section describes a multi-hop relay. A multi-hop relay may be a U2N relay in which multiple relay terminals intervene in a single path from a remote terminal device to gNB102. Figure 11 shows an example of the C-plane protocol stack in a multi-hop relay. For example, among the multiple relay terminals, the relay terminal directly connected to gNB102 via the Uu interface may be called the last relay terminal (MH U2N Last Relay UE in Figure 11), and among the multiple relay terminals, the relay terminals other than the last relay terminal (UEs belonging to the dotted line area, including MH U2N First Relay UE in Figure 11) may be called intermediate relay terminals. The intermediate relay terminals may be called the first relay terminal, second relay terminal, third relay terminal, etc., in order of hop proximity to the remote terminal device. The multiple relay terminals may be terminals that provide connectivity to the gNB from the remote terminal device. The names of the terminals described above are examples and are not limited to them. Note that Figure 11 is an example of the C-plane protocol stack, and the implementation method is not limited to this. A similar structure may also be used for the U-plane protocol stack. For example, the SDAP layer may be used instead of the RRC layer in the figure. In addition, in a multi-hop relay, if the node to which the link with the remote UE terminates is a base station device, as shown in Figure 11, it may be called a multi-hop U2N relay, and if the node to which the link with the remote UE terminates is a UE, it may be called a multi-hop U2U relay.

[0075] Next, the protocol configuration used between the base station equipment and the terminal equipment will be described. In communication conducted via the Uu interface between the relay terminal equipment and the base station equipment, and in communication conducted between the remote terminal equipment and the base station equipment via the relay terminal equipment, the protocol used between the base station equipment and the terminal equipment may be used. However, in communication conducted between the remote terminal equipment and the base station equipment via the relay terminal equipment, some protocols do not need to be associated between the remote terminal equipment and the base station equipment.

[0076] Figure 7 is a diagram showing an example of the NR protocol configuration according to this embodiment. The functions of each protocol described using Figure 7 are some of the functions closely related to this embodiment, and other functions may also be present. In this embodiment, the uplink (UL) may be a link from a terminal device to a base station device. Also in this embodiment, the downlink (DL) may be a link from a base station device to a terminal device.

[0077] Figure 7(A) is a diagram of the NR control plane (CP) protocol stack. As shown in Figure 7(A), the NR CP protocol may be a protocol between UE122 and gNB102. That is, the NR CP protocol may be a protocol that terminates at gNB102 on the network side. As shown in Figure 7(A), the NR control plane protocol stack may consist of the radio physical layer (PHY) 700, the medium access control layer (MAC) 702, the radio link control layer (RLC) 704, the packet data convergence protocol layer (PDCP) 706, and the radio resource control layer (RRC) 708. Figure 7(B) is a diagram of the NR user plane (UP) protocol stack. As shown in Figure 7(B), the NR UP protocol may be a protocol between UE122 and gNB102. That is, the NR UP protocol may be a protocol that terminates at gNB102 on the network side. As shown in Figure 7(B), the NR user plane protocol stack may consist of the wireless physical layer PHY700, the media access control layer MAC702, the wireless link control layer RLC704, the packet data convergence protocol layer PDCP706, and the service data adaptation protocol layer (service data adaptation protocol layer) SDAP (Service Data Adaptation Protocol)710.

[0078] The AS (Access Stratum) layer may be the layer that terminates between UE122 and gNB102. That is, the AS layer may be a layer that includes some or all of PHY700, MAC702, RLC704, PDCP706, and RRC708. Also, gNB102 may be ng-eNB100. Furthermore, although only the NR protocol is shown, the E-UTRA protocol may also be used. In the E-UTRA protocol, SDAP710 does not need to be present, and the E-UTRA protocol may have some functions that differ from the NR protocol.

[0079] In this embodiment, the terms PHY (PHY layer), MAC (MAC layer), RLC (RLC layer), PDCP (PDCP layer), and RRC (RRC layer) may be used without distinguishing between the E-UTRA protocol and the NR protocol. In this case, PHY (PHY layer), MAC (MAC layer), RLC (RLC layer), PDCP (PDCP layer), and RRC (RRC layer) may be the PHY (PHY layer), MAC (MAC layer), RLC (RLC layer), PDCP (PDCP layer), and RRC (RRC layer) of the E-UTRA protocol, or the PHY (PHY layer), MAC (MAC layer), RLC (RLC layer), PDCP (PDCP layer), and RRC (RRC layer) of the NR protocol, respectively. Also, SDAP (SDAP layer) may be the SDAP (SDAP layer) of the NR protocol.

[0080] Furthermore, in this embodiment, when distinguishing between the E-UTRA protocol and the NR protocol, PHY500, MAC502, RLC504, PDCP506, and RRC508 may also be referred to as E-UTRA PHY or LTE PHY, E-UTRA MAC or LTE MAC, E-UTRA RLC or LTE RLC, E-UTRA PDCP or LTE PDCP, and E-UTRA RRC or LTE RRC, respectively. Additionally, PHY500, MAC502, RLC504, PDCP506, and RRC508 may also be described as E-UTRA PHY or LTE PHY, E-UTRA MAC or LTEMAC, E-UTRA RLC or LTE RLC, E-UTRA PDCP or LTE PDCP, and E-UTRA RRC or LTE RRC, respectively. Furthermore, when distinguishing between the E-UTRA protocol and the NR protocol, PHY500, MAC502, RLC504, PDCP506, and RRC508 are sometimes referred to as NR PHY, NR MAC, NR RLC, NR RLC, and NR RRC, respectively. Additionally, PHY500, MAC502, RLC504, PDCP506, and RRC508 may be written as NR PHY, NR MAC, NR RLC, NR PDCP, and NR RRC, respectively.

[0081] This section describes entities in the AS layer of E-UTRA and / or NR. Entities that possess some or all of the functions of the physical layer may be called PHY entities. Entities that possess some or all of the functions of the MAC layer may be called MAC entities. Entities that possess some or all of the functions of the RLC layer may be called RLC entities. Entities that possess some or all of the functions of the PDCP layer may be called PDCP entities. Entities that possess some or all of the functions of the SDAP layer may be called SDAP entities. Entities that possess some or all of the functions of the RRC layer may be called RRC entities. PHY entities, MAC entities, RLC entities, PDCP entities, SDAP entities, and RRC entities may be replaced with PHY, MAC, RLC, PDCP, SDAP, and RRC, respectively.

[0082] Furthermore, the data provided from MAC, RLC, PDCP, and SDAP to lower layers, and / or the data provided from lower layers to MAC, RLC, PDCP, and SDAP, may be referred to as MAC PDU (Protocol Data Unit), RLC PDU, PDCP PDU, and SDAP PDU, respectively. Also, the data provided from higher layers to MAC, RLC, PDCP, and SDAP, and / or the data provided from MAC, RLC, PDCP, and SDAP to higher layers, may be referred to as MAC SDU (Service Data Unit), RLC SDU, PDCP SDU, and SDAP SDU, respectively. In addition, a segmented RLC SDU may be referred to as an RLC SDU segment.

[0083] Here, the base station equipment and the terminal equipment exchange (send and receive) signals at the higher layer. The higher layer may also be called the upper layer, and they are interchangeable. For example, the base station equipment and the terminal equipment may send and receive RRC messages (also called RRC message or RRC signalling) at the Radio Resource Control (RRC) layer. Also, the base station equipment and the terminal equipment may send and receive MAC control elements at the MAC (Medium Access Control) layer. Furthermore, the RRC layer of the terminal equipment acquires system information broadcast from the base station equipment. Here, RRC messages, system information, and / or MAC control elements are also called higher layer signals (higher layer signaling) or higher layer parameters (higher layer parameters). Each of the parameters included in the higher layer signal received by the terminal equipment may also be called a higher layer parameter. For example, in the processing of the PHY layer, the upper layer refers to the layer above the PHY layer, and may refer to one or more of the MAC layer, RRC layer, RLC layer, PDCP layer, NAS (Non-Access Stratum) layer, etc. For example, in the processing of the MAC layer, the upper layer may refer to one or more of the RRC layer, RLC layer, PDCP layer, NAS layer, etc.

[0084] In the following, the meaning of “A is provided at the upper layer” or “A is provided by the upper layer” may mean that the upper layer of the terminal device (mainly the RRC layer or MAC layer, etc.) receives A from the base station device, and that received A is provided from the upper layer of the terminal device to the physical layer of the terminal device. For example, “being provided with upper layer parameters” in a terminal device may mean that the terminal device receives an upper layer signal from the base station device, and the upper layer parameters included in the received upper layer signal are provided from the upper layer of the terminal device to the physical layer of the terminal device. Setting upper layer parameters in a terminal device may mean that the upper layer parameters are provided to the terminal device. For example, setting upper layer parameters in a terminal device may mean that the terminal device receives an upper layer signal from the base station device and sets the received upper layer parameters at the upper layer. However, setting upper layer parameters in a terminal device may also include setting default parameters that are pre-provided to the upper layer of the terminal device. When describing the transmission of an RRC message from a terminal device to a base station device, the expression “submitting a message from the RRC entity of the terminal device to the lower layer” may be used. In a terminal device, "submitting a message to a lower layer" from an RRC entity may mean submitting a message to the PDCP layer. In a terminal device, "submitting a message to a lower layer" from the RRC layer may mean submitting the message to the PDCP entity corresponding to each SRB (SRB0, SRB1, SRB2, SRB3, etc.), since RRC messages are transmitted using SRBs. When an RRC entity in a terminal device receives an indication from a lower layer, that lower layer may mean one or more layers such as the PHY layer, MAC layer, RLC layer, PDCP layer, etc.

[0085] An example of PHY functionality is described below. The terminal device's PHY may have the function of receiving data transmitted from the base station device's PHY via the Downlink (DL) physical channel. The terminal device's PHY may also have the function of transmitting data to the base station device's PHY via the Uplink (UL) physical channel. The PHY may be connected to a higher-level MAC via a Transport Channel. The PHY may transfer data to the MAC via the Transport Channel. The PHY may also receive data from the MAC via the Transport Channel. In the PHY, an RNTI (Radio Network Temporary Identifier) ​​may be used to identify various control information.

[0086] Now, let's explain physical channels. The following physical channels may be included in the physical channels used for wireless communication between terminal equipment and base station equipment.

[0087] PBCH (Physical Broadcast Channel), PDCCH (Physical Downlink Control Channel), PDSCH (Physical Downlink Shared Channel), PUCCH (Physical Uplink Control Channel), PUSCH (Physical Uplink Shared Channel), PRACH (Physical Random Access Channel)

[0088] PBCH may be used to broadcast system information required by terminal devices.

[0089] Furthermore, in NR, the PBCH may be used to announce the time index (SSB-Index) within the period of the Synchronization Signal Block (SSB).

[0090] PDCCH may be used to transmit (or carry) Downlink Control Information (DCI) in downlink wireless communication (wireless communication from base station equipment to terminal equipment). Here, one or more DCIs (which may also be called DCI formats) may be defined for the transmission of downlink control information. That is, fields for downlink control information may be defined as DCIs and mapped to information bits. PDCCH may be transmitted in PDCCH candidates. Terminal equipment may monitor a set of PDCCH candidates in a serving cell. Monitoring a set of PDCCH candidates may mean attempting to decode a PDCCH according to a certain DCI format. Terminal equipment may also monitor PDCCH candidates in configured monitoring occasions within one or more configured control resource sets (CORESET) set by the search space configuration. The DCI format may be used for scheduling PUSCHs in a serving cell. PUSCHs may be used for transmitting user data or RRC messages, as described later.

[0091] PDCCH repetition may be operated using two search space sets explicitly linked by a configuration provided by the upper layer (RRC layer). The two linked search space sets may also be associated with corresponding CORESETs. For PDCCH repetition, the two linked search space sets may be configured on the terminal device with the same number of PDCCH candidates. Two PDCCH candidates present in the two linked search space sets may be linked by the same candidate index. When PDCCH repetition is scheduled on the terminal device, inter-slot repetition may be permitted, and each repetition may have the same number of Control Channel Elements (CCEs), coded bits, and the same DCI payload.

[0092] PUCCH may be used to transmit Uplink Control Information (UCI) in uplink wireless communication (wireless communication from terminal equipment to base station equipment). Here, Uplink Control Information may include Channel State Information (CSI), which is used to indicate the state of the downlink channel. Furthermore, Uplink Control Information may include Scheduling Requests (SR), which are used to request UL-SCH (Uplink Shared Channel) resources. Furthermore, Uplink Control Information may include HARQ-ACK (Hybrid Automatic Repeat reQuest ACKnowledgement).

[0093] PDSCH may be used to transmit downlink data (DL-SCH: Downlink Shared Channel) from the MAC layer. In the case of downlinks, PDSCH may also be used to transmit system information (SI) and random access responses (RAR).

[0094] PUSCH may be used to transmit uplink data (UL-SCH: Uplink Shared Channel) from the MAC layer or HARQ-ACK and / or CSI along with uplink data. Alternatively, PUSCH may be used to transmit only CSI, or only HARQ-ACK and CSI. In other words, PUSCH may be used to transmit only UCI. Furthermore, PDSCH or PUSCH may be used to transmit RRC messages and MAC CE, which will be described later. Here, in PDSCH, the RRC message transmitted from the base station equipment may be a common signaling to multiple terminal devices within a cell. Alternatively, the RRC message transmitted from the base station equipment may be dedicated signaling to a particular terminal device. In other words, UE-specific information may be transmitted using dedicated signaling to a particular terminal device. Furthermore, PUSCH may be used to transmit UE Capability on the uplink.

[0095] PRACH may be used to send a random access preamble. PRACH may also be used to indicate the initial connection establishment procedure, handover procedure, connection re-establishment procedure, synchronization (timing adjustment) for uplink transmissions, and requests for UL-SCH resources.

[0096] An example of MAC functionality is described below. MAC may also be called a MAC sublayer. MAC may have the function of mapping various logical channels to corresponding transport channels. Logical channels may be identified by a Logical Channel Identity (Logical Channel ID). MAC may be connected to the higher-level RLC via logical channels. Logical channels may be divided into control channels that transmit control information and traffic channels that transmit user information, depending on the type of information being transmitted. Logical channels may also be divided into uplink logical channels and downlink logical channels. MAC may have the function of multiplexing MAC SDUs belonging to one or more different logical channels and providing them to the PHY. MAC may also have the function of demultiplexing MAC PDUs provided from the PHY and providing them to the higher layer via the logical channel to which each MAC SDU belongs. MAC may also have the function of performing error correction through HARQ (Hybrid Automatic Repeat reQuest). The MAC may also have a function to report scheduling information. The MAC may have a function to prioritize between terminal devices using dynamic scheduling. The MAC may also have a function to prioritize between logical channels within a single terminal device. The MAC may also have a function to prioritize overlapping resources within a single terminal device. The E-UTRA MAC may have a function to identify Multimedia Broadcast Multicast Services (MBMS). The NR MAC may also have a function to identify Multicast Broadcast Service (MBS). The MAC may have a function to select the transport format.A MAC may have functions for discontinuous reception (DRX) and / or discontinuous transmission (DTX), random access (RA) procedures, a power headroom report (PHR) function to notify information on available power, and a buffer status report (BSR) function to notify information on the amount of data in the transmit buffer. An NR MAC may have a bandwidth adaptation (BA) function. The MAC PDU format used in E-UTRA MACs and the MAC PDU format used in NR MACs may be different. A MAC PDU may also include MAC control elements (MAC CEs), which are elements for controlling the MAC.

[0097] This document describes the logical channels used for uplink (UL) and / or downlink (DL) in E-UTRA and / or NR.

[0098] BCCH (Broadcast Control Channel) may be a downlink logical channel for broadcasting control information, such as system information (SI).

[0099] A PCCH (Paging Control Channel) may be a downlink logical channel for carrying paging messages.

[0100] A Common Control Channel (CCCH) may be a logical channel for transmitting control information between a terminal device and a base station device. A CCCH may be used when a terminal device does not have an RRC connection. A CCCH may also be used between a base station device and multiple terminal devices.

[0101] A DCCH (Dedicated Control Channel) may be a logical channel for transmitting dedicated control information in a point-to-point, bidirectional manner between a terminal device and a base station device. Dedicated control information may be control information specific to each terminal device. A DCCH may be used when the terminal device has an RRC connection.

[0102] A Dedicated Traffic Channel (DTCH) may be a logical channel for transmitting user data point-to-point between a terminal device and a base station device. A DTCH may be a logical channel for transmitting dedicated user data. Dedicated user data may be user data specific to each terminal device. A DTCH may exist on both the uplink and downlink.

[0103] This section describes the mapping between logical channels and transport channels for uplinks in E-UTRA and / or NR.

[0104] CCCH may be mapped to UL-SCH (Uplink Shared Channel), which is an uplink transport channel.

[0105] DCCH may be mapped to UL-SCH (Uplink Shared Channel), which is an uplink transport channel.

[0106] DTCH may be mapped to UL-SCH (Uplink Shared Channel), which is an uplink transport channel.

[0107] This section describes the mapping between logical channels and transport channels for downlinks in E-UTRA and / or NR.

[0108] BCCH may be mapped to a downlink transport channel, BCH (Broadcast Channel), and / or DL-SCH (Downlink Shared Channel).

[0109] The PCCH may be mapped to the PCH (Paging Channel), which is a downlink transport channel.

[0110] CCCH may be mapped to DL-SCH (Downlink Shared Channel), which is a downlink transport channel.

[0111] DCCH may be mapped to DL-SCH (Downlink Shared Channel), which is a downlink transport channel.

[0112] DTCH may be mapped to DL-SCH (Downlink Shared Channel), which is a downlink transport channel.

[0113] An example of RLC functionality is described below. RLC may also be called an RLC sublayer. E-UTRA RLC may have the functionality to segment and / or concatenate data provided from the upper layer PDCP and provide it to the lower layer. E-UTRA RLC may have the functionality to reassemble and reorder data provided from the lower layer and provide it to the upper layer. NR RLC may have the functionality to add a sequence number to data provided from the upper layer PDCP that is independent of the sequence number added by the PDCP. NR RLC may also have the functionality to segment the data provided from the PDCP and provide it to the lower layer. NR RLC may also have the functionality to reassemble data provided from the lower layer and provide it to the upper layer. RLC may also have a data retransmission function and / or an automatic repeat request (ARQ) function. RLC may also have a function to perform error correction using ARQ. The control information sent from the receiver to the transmitter of RLC to perform ARQ, indicating data that needs to be retransmitted, may be called a status report. The instruction to send a status report sent from the transmitter to the receiver of RLC may be called a poll. RLC may also have a function to detect data duplication. RLC may also have a function to discard data. RLC may have three modes: Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode (AM). In TM, data received from the upper layer is not split, and an RLC header does not need to be added. A TM RLC entity is a unidirectional entity and may be configured as a transmitting TM RLC entity or a receiving TM RLC entity.UM performs tasks such as splitting and / or combining data received from higher layers and adding RLC headers, but does not need to control data retransmission. UM RLC entities may be unidirectional or bidirectional. If a UM RLC entity is unidirectional, it may be configured as a transmitting UM RLC entity or a receiving UM RLC entity. If a UM RLC entity is bidirectional, it may be configured as a UM RLC entity consisting of a transmitting side and a receiving side. AM may perform tasks such as splitting and / or combining data received from higher layers, adding RLC headers, and controlling data retransmission. AM RLC entities are bidirectional entities and may be configured as AM RLCs consisting of a transmitting side and a receiving side. Data provided to lower layers by TM, and / or data provided by lower layers, may be called TMD PDUs. Similarly, data provided to lower layers by UM, and / or data provided by lower layers, may be called UMD PDUs. Furthermore, data provided to lower layers by AM, or data provided by lower layers, may be called AMD PDUs. The RLC PDU format used in E-UTRA RLC and the RLC PDU format used in NR RLC may be different. Also, there may be data RLC PDUs and control RLC PDUs. Data RLC PDUs may be called RLC DATA PDUs (RLC Data PDUs). Control RLC PDUs may be called RLC CONTROL PDUs (RLC Control PDUs).

[0114] This section describes some examples of PDCP functionality. PDCP may be referred to as the PDCP sublayer. PDCP may have a function for maintaining sequence numbers. PDCP may also have a header compression / decompression function for efficiently transmitting user data such as IP packets and Ethernet frames over the wireless section. The protocol used for compressing and decompressing IP packet headers may be called the ROHC (Robust Header Compression) protocol. The protocol used for compressing and decompressing Ethernet frame headers may be called the EHC (Ethernet® Header Compression) protocol. PDCP may also have data encryption / decryption functions. PDCP may also have data integrity protection and integrity verification functions. PDCP may also have a re-ordering function. PDCP may also have a PDCP SDU retransmission function. PDCP may also have a data discard function using a discard timer. PDCP may also have a duplication function. PDCP may also have a function for discarding duplicate received data. A PDCP entity is a bidirectional entity and may consist of a transmitting PDCP entity and a receiving PDCP entity. The PDCP PDU format used in E-UTRA PDCP and the PDCP PDU format used in NR PDCP may be different. Furthermore, there may be data PDCP PDUs and control PDCP PDUs. The data PDCP PDU may be called a PDCP DATA PDU (PDCP Data PDU). The control PDCP PDU may be called a PDCP CONTROL PDU (PDCP Control PDU).

[0115] This section describes an example of SDAP functionality. SDAP is a Service Data Adaptive Protocol Layer (SPD). SDAP may have the functionality to map downlink QoS flows sent from 5GC to terminal devices via base station equipment to data radio bearers (DRBs), and / or to map uplink QoS flows sent from terminal devices to 5GC via base station equipment to DRBs. SDAP may also have the functionality to store mapping rule information. SDAP may also have the functionality to mark QoS flow identifiers (QoS Flow IDs: QFIs). Note that there may be data SDAP PDUs and control SDAP PDUs. Data SDAP PDUs may be called SDAP DATA PDUs (SDAP Data PDUs). Control SDAP PDUs may be called SDAP CONTROL PDUs (SDAP Control PDUs). Note that there may be one SDAP entity for each PDU session in a terminal device.

[0116] An example of RRC functionality is described below. RRC may have broadcast functionality. RRC may have paging functionality from 5GC. RRC may have paging functionality from gNB102 or ng-eNB100. RRC may also have RRC connection management functionality. RRC may also have wireless bearer control functionality. RRC may also have cell group control functionality. RRC may also have mobility control functionality. RRC may also have terminal device measurement reporting and terminal device measurement reporting control functionality. RRC may also have QoS management functionality. RRC may also have wireless link failure detection and recovery functionality. RRC may use RRC messages to perform broadcasting, paging, RRC connection management, wireless bearer control, cell group control, mobility control, terminal device measurement reporting and terminal device measurement reporting control, QoS management, wireless link failure detection and recovery, etc. Note that the RRC messages and parameters used in E-UTRA RRC may differ from those used in NR RRC. Furthermore, RRC messages may contain multiple information elements (IEs) for the control functions described above.

[0117] RRC messages may be sent using the logical channels BCCH, PCCH, CCCH, or DCCH. RRC messages sent using DCCH are referred to as dedicated RRC signaling or simply RRC signaling.

[0118] RRC messages sent using BCCH may include, for example, a Master Information Block (MIB), a System Information Block (SIB) of each type, or other RRC messages. RRC messages sent using PCCH may include, for example, a paging message or other RRC messages.

[0119] RRC messages sent in the uplink (UL) direction using CCCH may include, for example, RRC Setup Request, RRC Resume Request, RRC Reestablishment Request, and RRC System Info Request. They may also include, for example, RRC Connection Request, RRC Connection Resume Request, and RRC Connection Reestablishment Request. Other RRC messages may also be included.

[0120] RRC messages sent in the downlink (DL) direction using CCCH may include, for example, RRC Connection Reject messages, RRC Connection Setup messages, RRC Connection Reestablishment messages, and RRC Connection Reestablishment Reject messages. They may also include, for example, RRC Reject messages and RRC Setup messages. Other RRC messages may also be included.

[0121] RRC signaling sent in the uplink (UL) direction using DCCH may include, for example, a Measurement Report message, an RRC Connection Reconfiguration Complete message, an RRC Connection Setup Complete message, an RRC Connection Reestablishment Complete message, a Security Mode Complete message, and an UE Capability Information message. It may also include, for example, a Measurement Report message, an RRC Reconfiguration Complete message, an RRC Setup Complete message, an RRC Reestablishment Complete message, an RRC Resume Complete message, a Security Mode Complete message, and an UE Capability Information message. Other RRC signaling may also be included.

[0122] RRC signaling sent in the downlink (DL) direction using DCCH may include, for example, RRC Connection Reconfiguration messages, RRC Connection Release messages, Security Mode Command messages, and UE Capability Enquiry messages. It may also include, for example, RRC Reconfiguration messages, RRC Resume messages, RRC Release messages, RRC Reestablishment messages, Security Mode Command messages, and UE Capability Enquiry messages. Other RRC signaling may also be included.

[0123] The aforementioned PHY, MAC, RLC, PDCP, SDAP, and RRC functions are merely examples, and some or all of each function may not be implemented. Furthermore, some or all of the functions of each layer may be included in other layers.

[0124] This section describes radio bearers. When a terminal device communicates with a base station device, a radio connection may be established between the terminal device and the base station device by establishing a radio bearer (RB). A radio bearer used in CP may be called a signaling radio bearer (SRB). A radio bearer used in UP may be called a data radio bearer (DRB). Each radio bearer may be assigned a radio bearer identifier (Identity: ID). The radio bearer identifier for SRBs may be called an SRB identifier (SRB Identity, or SRB ID). The radio bearer identifier for DRBs may be called a DRB identifier (DRB Identity, or DRB ID). For E-UTRA, SRB0 to SRB2 may be defined, and other SRBs may also be defined. For NR, SRB0 to SRB3 may be defined, and other SRBs may also be defined. SRB0 may be an SRB for RRC messages, transmitted and / or received using the logical channel CCCH. SRB1 may be an SRB for RRC signaling and for NAS signaling before SRB2 is established. RRC signaling transmitted and / or received using SRB1 may include piggybacked NAS signaling. All RRC and NAS signaling transmitted and / or received using SRB1 may use the logical channel DCCH. SRB2 may be an SRB for NAS signaling and for RRC signaling including logged measurement information. All RRC and NAS signaling transmitted and / or received using SRB2 may use the logical channel DCCH. SRB2 may also have a lower priority than SRB1. SRB3 may be an SRB for transmitting and / or receiving specific RRC signaling when EN-DC, NGEN-DC, NR-DC, etc. are configured on the terminal device.The DCCH logical channel may be used for all RRC signaling and / or NAS signaling transmitted and / or received using SRB3. Other SRBs may be provided for other purposes. The DRB may be a radio bearer for user data. The DTCH logical channel may be used for RRC signaling transmitted and / or received using the DRB.

[0125] This section describes the radio bearer in a terminal device. The radio bearer may include an RLC bearer. An RLC bearer may consist of one or two RLC entities and a logical channel. If there are two RLC entities in an RLC bearer, the RLC entities may be a TM RLC entity and / or a unidirectional UM mode RLC entity, specifically a transmit RLC entity and a receive RLC entity. SRB0 may consist of one RLC bearer. The RLC bearer of SRB0 may consist of a TM RLC entity and a logical channel. SRB0 may always be established in a terminal device in all RRC states (RRC idle state, RRC connected state, and RRC inactive state, etc.). SRB1 may be established and / or set in a terminal device by RRC signaling received from the base station device when the terminal device transitions from the RRC idle state to the RRC connected state. SRB1 may consist of one PDCP entity and one or more RLC bearers. The RLC bearer of SRB1 may consist of an AM RLC entity and a logical channel. SRB2 may be established and / or configured on a terminal device by RRC signaling received from the base station device by a terminal device in an RRC connection state with AS security activated. SRB2 may consist of one PDCP entity and one or more RLC bearers. The RLC bearer of SRB2 may consist of an AM RLC entity and a logical channel. Note that the PDCP on the base station side of SRB1 and SRB2 may be located on the master node. SRB3 may be established and / or configured on a terminal device by RRC signaling received from the base station device by a terminal device in an RRC connection state with AS security activated when a secondary node is added or when a secondary node is changed in an EN-DC, NGEN-DC, or NR-DC. SRB3 may be a direct SRB between the terminal device and the secondary node. SRB3 may consist of one PDCP entity and one or more RLC bearers. The RLC bearer of SRB3 may consist of an AM RLC entity and a logical channel.The PDCP on the base station side of SRB3 may be located on a secondary node. One or more DRBs may be established and / or configured on a terminal device by RRC signaling received from the base station device by a terminal device in an RRC connection state with AS security activated. A DRB may consist of one PDCP entity and one or more RLC bearers. The RLC bearers of a DRB may consist of an AM or UM RLC entity and a logical channel.

[0126] For RLC bearers established and / or configured in cell groups composed of E-UTRA, the established and / or configured RLC entities may be E-UTRA RLC. Similarly, for RLC bearers established and / or configured in cell groups composed of NR, the established and / or configured RLC entities may be NR RLC. When EN-DC is configured on terminal equipment, the PDCP entities established and / or configured for MN (Master Node) terminated MCG bearers may be either E-UTRA PDCP or NR PDCP. Furthermore, when EN-DC is configured on terminal equipment, the PDCPs established and / or configured for other bearer types of wireless bearers, namely MN terminated split bearers, MN terminated SCG bearers, SN (Secondary Node) terminated MCG bearers, SN terminated split bearers, and SN terminated SCG bearers, may be NR PDCP. Furthermore, if NGEN-DC, NE-DC, or NR-DC is configured on the terminal device, the PDCP entities established and / or configured for wireless bearers of all bearer types may be NR PDCPs.

[0127] In NR, the DRB established and / or configured on the terminal device may be associated with one PDU session. One SDAP entity may be established and / or configured for one PDU session on the terminal device. The SDAP entities, PDCP entities, RLC entities, and logical channels established and / or configured on the terminal device may be established and / or configured by RRC signaling received by the terminal device from the base station device.

[0128] The Reference Signal Received Power (RSRP) measured in the sidelink may be, for example, one of the following RSRPs. Furthermore, the following RSRPs may be referred to as SL-RSRP. (a) PSBCH RSRP (b) PSSCH RSRP (c) PSCCH RSRP

[0129] PSBCH-RSRP (PSBCH RSRP) may be defined as the linear average of the power contributions of resource elements that transmit multiple Demodulation Reference Signals (DMRS) associated with a PSBCH. Similarly, PSSCH-RSRP (PSSCH RSRP) may be defined as the linear average of the power contributions of resource elements at an antenna port that transmits multiple DMRS associated with a PSSCH, and if there are multiple antenna ports, the RSRP values ​​for each antenna port may be summed up. PSCCH-RSRP (PSCCH RSRP) may be defined as the linear average of the power contributions of resource elements that transmit multiple DMRS associated with a PSCCH. Note that DMRS may be used, for example, to demodulate the signals of PSBCH, PSSCH, and PSCCH. Furthermore, a terminal device that performs side-link communication with other terminal devices may measure the RSRP of the side-link communication (SL-RSRP) using PSSCH or PSCCH transmitted from the other terminal device. Furthermore, the terminal device may measure the RSRP (SD-RSRP) of the discovery message using the power contribution of the resource element that transmits the DMRS associated with the discovery message.

[0130] Furthermore, in measurements at the sidelink, the UE122 may measure the following quantities in addition to SL-RSRP: (a) Sidelink received signal strength indicator (SL RSSI) (b) Sidelink channel occupancy ratio (SL CR) (c) Sidelink channel busy ratio (SL CBR)

[0131] The SL RSSI may be defined as the linear average of the power ([W]) observed in the configured subchannels within the OFDM symbols of the slots configured for PSCCH and PSSCH, starting from the second OFDM symbol. The SL CR in slot n may be defined as the sum of the number of subchannels used for sidelink transmission between slots [na] and [n-1] and the number of subchannels allocated between slots [n] and [n+b], divided by the total number of subchannels set between slots [na] and [n+b]. The SL CBR in slot n may be defined as the percentage of subchannels in the resource pool whose SL RSSI exceeds a threshold during the period set as the CBR measurement window (slots [na] to slots [n-1]).

[0132] An L2 U2N Remote UE may discover candidate L2 U2N Relay UEs, measure the RSRP of the candidate L2 U2N Relay UEs, and then report one or more candidate L2 U2N Relay UEs to the base station equipment. Before reporting one or more candidate L2 U2N Relay UEs to the base station equipment, the L2 U2N Remote UE may determine whether the measured RSRP of the candidate L2 U2N Relay UEs satisfies the selection criteria for L2 U2N relays. The L2 U2N Remote UE may report only candidate L2 U2N Relay UEs that satisfy the selection criteria and also conform to the criteria of the higher layer to the base station equipment. Furthermore, when reporting one or more candidate L2 U2N Relay UEs to the base station equipment, the L2 U2N Remote UE may include the identification information of the candidate L2 U2N Relay UE, the identification information of the serving cell of the candidate L2 U2N Relay UE, and the measurement results in its report to the base station equipment. The measurement results may include the RSRP (SD-RSRP) of the discovery message transmitted by the candidate L2 U2NRelay UE. The identification information may be an identifier (ID).

[0133] Furthermore, an L2 U2N Remote UE having a Serving L2 U2N Relay UE may use the RSRP (SL-RSRP) measured in sidelink communication with the Serving L2 U2N Relay UE in the measurement results. If SL-RSRP cannot be used in the measurement results, SD-RSRP may be used. The Serving L2 U2N Relay UE may be an L2 U2N Relay UE that provides connectivity to the base station equipment for the L2 U2N Remote UE.

[0134] Next, we will describe the Serving Cell. In a terminal device in the RRC_CONNECTED state with one Serving Cell configured, the Serving Cell may consist of one Primary Cell (PCell). In a terminal device in the RRC_CONNECTED state with multiple Serving Cells configured, the Serving Cell may mean a set of cells (set of cell(s)) consisting of one or more Special Cells (SpCell) and one or more all Secondary Cells (SCell). The SpCell may support PUCCH transmission and contention-based Random Access (CBRA). The PCell may be the cell used in the RRC connection establishment procedure when a terminal device in the RRC_IDLE state transitions to the RRC_CONNECTED state. The PCell may also be the cell used in the RRC connection re-establishment procedure when a terminal device re-establishes the RRC connection. Furthermore, the PCell may be the cell used in the random access procedure during handover. Furthermore, SpCell may be a cell used for purposes other than those mentioned above.

[0135] If a group of serving cells configured for a terminal device consists of a SpCell and one or more SCells, it may be considered that carrier aggregation (CA) is configured for the terminal device. Furthermore, for a terminal device with CA configured, a cell providing additional radio resources to a SpCell may mean an SCell.

[0136] This section describes a cell group, which is configured on a terminal device by a base station device. A cell group may consist of one SpCell. Alternatively, a cell group may consist of one SpCell and one or more SCells. In other words, a cell group may consist of one SpCell and, optionally, one or more SCells. A cell group may also be described as a set of cell(s).

[0137] UE122 may receive special cell (SpCell) settings from gNB102. For example, an RRC reconfiguration message may include a cell group setting (an information element named CellGroupConfig), and the cell group setting may include a special cell setting (an information element named spCellConfig). An information element named spCellConfigDedicated, included in the information element named spCellConfig, may be an information element indicating the cell setting for UE122 that is set by this SpCellConfig. The information element named spCellConfigDedicated may be rephrased as SpCellConfigDedicated or SpCell-specific setting. The information element named spCellConfigDedicated may include a parameter for the BWP identifier named firstActiveDownlinkBWP-Id, which will be described later. Furthermore, the special cell setting may include a reconfiguration with synchronization (an information element named reconfigurationWithSync). An information element named spCellConfigCommon, contained within an information element named reconfigurationWithSync, may be used to set cell-specific parameters of the serving cell (i.e., special cell) of the UE122. The term "IE" may be added to indicate that a certain statement is an information element. For example, a synchronized reconfiguration IE may be included in an RRC reconfiguration message, and the UE122, upon receiving the RRC reconfiguration message, may perform a synchronized reconfiguration (procedure) according to the RRC reconfiguration message.

[0138] The notification messages in a U2N relay are described below. The relay terminal device may send the notification message to the remote terminal device when it detects an RLF on the Uu interface, when it receives an RRC reset message containing a synchronous reset information element, when it initiates cell reselection, when it detects an RRC connection failure (including RRC connection rejection), when T300 expires, or when it fails the RRC restart procedure. The relay terminal device may include a notification type in the notification message. The notification type may be set to a different value depending on the reason for initiating the transmission of the notification message, for example, it may indicate a wireless link failure on the Uu, a wireless link failure on the PC5 link, a failure of RRC reset, a handover by the relay terminal device, a cell reselection by the relay terminal device, or other types. The remote terminal device that receives the notification message may initiate an RRC connection re-establishment procedure based on the RRC_CONNECCTED state, or may notify the upper layer of the release of the PC5 unicast link based on the determination to release the PC5 RRC connection with the relay terminal device, or may consider that cell reselection has been initiated based on the notification type being relayUE-HO. The notification message may be a message named NotificationMessageSidelink or a message with another name. The notification type may be a message named IndicationType or a message with another name.

[0139] UE122, which performs sidelink transmission, transmits using sidelink grants (SL grants). Sidelink grants are dynamically received by PDCCH transmitted by the base station equipment, semi-persistently set by RRC signaling transmitted by the base station equipment, or automatically selected by the MAC entity of the terminal equipment. The transmission mode in which sidelink grants are automatically selected by the MAC entity of the terminal equipment may be called Mode 2, and the transmission modes in which sidelink grants are dynamically allocated by PDCCH transmitted by the base station equipment and semi-persistently set by RRC signaling received from the base station equipment may be called Mode 1. Mode 1 and Mode 2 may each be modes of sidelink resource allocation.

[0140] Sidelink-enabled terminal devices may transmit a sidelink terminal information message to a base station device. The sidelink terminal information message may be a type of RRC message. Furthermore, terminal devices in the RRC_CONNECTED state that are capable of sending and receiving discovery messages, or terminal devices capable of U2N relay operations, U2U relay operations, sidelink positioning, or other operations may transmit the sidelink terminal information message to a base station device. The sidelink-enabled terminal devices may transmit the sidelink terminal information message to the base station device to indicate their interest in sending and receiving sidelink communications, sending and receiving discovery messages, U2N relay operations, U2U relay operations, sending and receiving SL-PRS, or other operations. The sidelink terminal information message may be a message used to notify the network of sidelink terminal information. The Sidelink terminal information message may be sent when the connection with the base station equipment is successfully established or re-established, when there is a change in interest, when the QoS profile changes, when sidelink-related capability information is received from the associated peer UE, when RLC mode information is updated from the associated peer UE, when the PCell providing SIB12 including sidelink common settings (sl-ConfigCommonNR) is changed, or when the PCell providing SIB23 including sidelink positioning common settings (sl-PosConfigCommonNR) is changed. A Sidelink-enabled terminal device may also send the Sidelink terminal information message to request the allocation of a dedicated sidelink DRB setting and to request the allocation of transmission resources for sidelink communication. A Sidelink-enabled terminal device may also send the Sidelink terminal information message to report to the network (the base station equipment) that a sidelink radio link failure, sidelink RRC reconfiguration failure, sidelink carrier failure, etc., has been declared.A terminal device capable of sending and receiving discovery messages may send the sidelink terminal information message to request the allocation of dedicated resources for sending and receiving discovery messages. A terminal device capable of U2N relay operation may send the sidelink terminal information message to report or update parameters for acting as a U2N relay UE or U2N remote UE. A terminal device capable of U2U relay operation may send the sidelink terminal information message to report or update parameters for acting as a U2U relay UE or U2U remote UE. A terminal device capable of sidelink positioning may send the sidelink terminal information message to request whether it is interested in or no longer interested in either sending or receiving SL-PRS.

[0141] The terminal device may send the sidelink terminal information message when PCell provides an SIB12 containing sidelink common settings. The terminal device may include several information elements in the sidelink terminal information message. The terminal device may include all relevant information (information elements) in the sidelink terminal information message regardless of the reason that triggered the transmission of the sidelink terminal information message. For example, it may include an information element indicating whether the terminal device is playing the role of a U2N relay UE or a U2N remote UE. The information element indicating whether the terminal device is playing the role of a U2N relay UE or a U2N remote UE may be an information element named ue-Type and may take the value of either relayUE or remoteUE. For example, the terminal device may include ue-Type in the sidelink terminal information message and set the value of ue-Type to relayUE based on the determination that the terminal device is playing the role of a U2N relay UE, given that the SIB12 includes L2U2N relay settings and is configured by the upper layer to transmit U2N relay communication. For example, the terminal device may have its SIB12 configured to include an L2U2N relay setting and send U2N relay communications via a higher layer. Based on the determination that the terminal device is acting as a U2N remote UE, the ue-Type may be included in the sidelink terminal information message, and the value of the ue-Type may be set to remoteUE. That is, the value of ue-Type, relayUE, may indicate that the terminal device is acting as a U2N relay UE, or the value of ue-Type, remoteUE, may indicate that the terminal device is acting as a U2N remote UE. In addition, the sidelink terminal information message may include information elements other than ue-Type.For example, the information elements may include an index of frequencies of interest for receiving sidelink communications, an index of a source L2ID used to establish a PC5 link with a target U2N relay UE, an information element containing parameters for requesting resources for transmitting sidelink communications (to the associated destination UE), an information element containing parameters for requesting resources for transmitting discovery messages, an information element containing parameters for requesting transmission resources for U2N relay communications, and other information elements. For example, parameters for requesting transmission resources for U2N relay communications may include information indicating the destination L2ID for sidelink communications, an index of one or more frequencies of interest for transmitting U2N relay communications, a list of synchronization types associated with each of the one or more frequency indexes, information requesting the local ID of a U2N remote UE that has transitioned to RRC_CONNECTED or is in the RRC_CONNECTED state, a paging identifier received from a peer U2N remote UE, and information indicating the capability in sidelink communications received from a peer UE.

[0142] The aforementioned SIB12 may be a type of System Information Block (SIB) and may be set specifically for the cell or area transmitted by DL-SCH. The SIB12 may also be a system information block that includes settings for sending and receiving sidelink communication and / or discovery messages. The SIB12 may include information such as sidelink common settings, L2U2N relay settings, and U2N discovery common settings, and may also include other information. The sidelink common settings may include settings for sidelink transmission by mode 2, the frequency to be used, and wireless bearer settings. The L2U2N relay settings may be settings indicating that the cell providing the SIB12 supports L2U2N relay operation. The U2N discovery common settings include setting information for U2N relay UEs and / or U2N remote UEs, and the setting information may include threshold settings used for making decisions during discovery transmission and reception.

[0143] Based on the above description, various embodiments will be explained. Note that any processes omitted in the following description may be replaced by the processes described above.

[0144] Figure 5 is a block diagram showing the configuration of the terminal device (UE122) in this embodiment. Note that, to avoid complicating the explanation, Figure 5 only shows the main components closely related to this embodiment.

[0145] The UE122 shown in Figure 5 comprises a receiving unit 500 that receives control information (SCI, MAC control elements, RRC signaling, etc.), discovery messages, user data, etc., from other terminal devices; a processing unit 502 that processes according to the parameters contained in the received control information, etc.; and a transmitting unit 504 that transmits control information (SCI, MAC control elements, RRC signaling, etc.), discovery messages, user data, etc., to other terminal devices. The receiving unit 500 may also receive control information (MAC control elements, RRC signaling, etc.), user data, etc., from a base station device (gNB102). The transmitting unit 504 may also transmit control information (MAC control elements, RRC signaling, etc.), user data, etc., to the base station device (gNB102). Furthermore, the processing unit 502 may include some or all of the functions of various layers (for example, the physical layer, MAC layer, RLC layer, PDCP layer, SDAP layer, RRC layer, PC5-S layer, Discovery layer, and application layer). In other words, the processing unit 502 may include some or all of the physical layer processing unit (PHY processing unit), MAC layer processing unit (MAC processing unit), RLC layer processing unit (RLC processing unit), PDCP layer processing unit (PDCP processing unit), SDAP processing unit (SDAP processing unit), RRC layer processing unit (RRC processing unit), PC5-S layer processing unit (PC5-S processing unit), Discovery layer processing unit (Discovery processing unit), and application layer processing unit.

[0146] Figure 6 is a block diagram showing the configuration of the base station device (gNB102) in this embodiment. To avoid a complicated explanation, Figure 6 shows only the main components closely related to this embodiment.

[0147] The base station device shown in Figure 6 consists of a transmitting unit 604 that transmits control information (DCI, MAC CE, RRC signaling, etc.) to the UE 122, a processing unit 602 that creates control information (DCI, MAC CE, RRC signaling, etc.) and transmits it to the UE 122, causing the processing unit 502 of the UE 122 to perform processing, and a receiving unit 600 that receives control information (UCI, MAC CE, RRC signaling, etc.) from the UE 122. Furthermore, the processing unit 602 may include some or all of the functions of various layers (for example, the physical layer, MAC layer, RLC layer, PDCP layer, SDAP layer, RRC layer, and NAS layer). That is, the processing unit 602 may include some or all of the physical layer processing unit, MAC layer processing unit, RLC layer processing unit, PDCP layer processing unit, SDAP layer processing unit, RRC layer processing unit, and NAS layer processing unit.

[0148] In a multi-hop U2N relay that provides connectivity to a base station device using multiple U2N relay UEs for a U2N remote UE, the U2N relay UE that has a direct path (Uu link) to the base station device may be called the last relay UE, or simply the U2N relay UE. In the multi-hop U2N relay, the U2N relay UE that does not have a direct path to the base station device may be called an intermediate relay UE to distinguish it from the last relay UE. The intermediate relay UE may establish a PC5 link (or unicast link, PC5-RRC) connection with an adjacent U2N remote UE or another adjacent intermediate relay UE, or an adjacent last relay UE. In the multi-hop U2N relay, the U2N remote UE may establish a PC5 link (or unicast link, PC5-RRC) connection with the intermediate relay UE. The aforementioned U2N relay UEs and U2N remote UEs may maintain an RRC connection with the base station device when they are in the RRC_CONNECTED state. Note that U2N relay UEs and relay UEs may be interchangeable. Note that U2N remote UEs and remote UEs may be interchangeable. Note that U2N intermediate UEs, intermediate UEs, and intermediate relay UEs may be interchangeable.

[0149] Figure 10 shows an example of an embodiment of one aspect of the present invention.

[0150] The UE122, which communicates with the base station equipment, makes a decision (step S1000) and operates based on the decision (step S1002).

[0151] In the determination in step S1000, for example, UE122 may determine that UE122 will act as an intermediate relay UE. Based on the determination by UE122 that UE122 will act as an intermediate relay UE, in the operation in step S1002, for example, UE122 may include an information element in the sidelink terminal information message indicating that UE122 will act as an intermediate relay UE. The information element may be included in the RRC message to indicate that UE122 will act as an intermediate relay UE, or alternatively, the information element may be a variable that can take multiple values ​​and be set to a specific value among the multiple values ​​to indicate that UE122 will act as an intermediate relay UE, or alternatively, the information element may be a parameter that can store multiple values ​​and be included in the information element to indicate that UE122 will act as an intermediate relay UE.

[0152] In addition to or instead of the above, in the determination in step S1000, for example, UE122 may determine that UE122 does not perform the role of an intermediate relay UE. Based on the determination by UE122 that UE122 does not perform the role of an intermediate relay UE, in the operation in step S1002, for example, UE122 may include an information element in the sidelink terminal information message indicating that UE122 is performing the role of a remote UE. In addition to or instead of the above, in the determination in step S1000, for example, UE122 may determine that UE122 does not perform the role of an intermediate relay UE. Based on the fact that UE122 has determined that it does not perform the role of an intermediate relay UE, and that UE122 has determined that it does not perform the role of a remote UE, in the operation in step S1002, for example, UE122 may include an information element in the sidelink terminal information message indicating that UE122 is performing the role of a remote UE.

[0153] In addition to or instead of the above, in the determination in step S1000, for example, the UE122 may determine that some of the following conditions are met: (C-1) SIB12 includes an L2U2N relay setting; (C-2) The upper layer has configured the transmission of U2N relay communication; (C-3) The UE122 is acting as a relay UE; (C-4) The UE122 is acting as a remote UE; (C-5) SIB12 includes an L2U2N multihop relay setting; (C-6) The UE122 is acting as an intermediate relay UE; (C-7) The upper layer has configured the transmission of U2N multihop relay communication; (C-8) The UE122 is not acting as an intermediate relay UE.

[0154] For example, based on the UE122's determination that (C-1), (C-2), and (C-3) are satisfied, in the operation in step S1002, the UE122 may include an information element in the sidelink terminal information message indicating that the UE122 is acting as a relay UE.

[0155] In addition to or instead of the above, based on the UE122's determination that, for example, (C-1) and (C-2), (C-4) are satisfied, in the operation in step S1002, for example, the UE122 may include an information element in the sidelink terminal information message indicating that the UE122 is playing the role of a remote UE. Alternatively, based on the UE122's determination that, for example, (C-1) and (C-2), (C-4), (C-8) are satisfied, in the operation in step S1002, for example, the UE122 may include an information element in the sidelink terminal information message indicating that the UE122 is playing the role of a remote UE.

[0156] In addition to or instead of the above, based on the UE122's determination that, for example, (C-1) and (C-2), (C-6) are satisfied, in the operation in step S1002, for example, the UE122 may include an information element in the sidelink terminal information message indicating that the UE122 is playing the role of an intermediate relay UE. Alternatively, based on the UE122's determination that, for example, (C-1) and (C-6), (C-7) are satisfied, in the operation in step S1002, for example, the UE122 may include an information element in the sidelink terminal information message indicating that the UE122 is playing the role of an intermediate relay UE. Alternatively, based on the UE122's determination that, for example, (C-5) and (C-2), (C-6) are satisfied, in the operation in step S1002, for example, the UE122 may include an information element in the sidelink terminal information message indicating that the UE122 is playing the role of an intermediate relay UE. Alternatively, based on the UE122's determination that, for example, (C-1), (C-7), and (C-6) are satisfied, in the operation in step S1002, the UE122 may, for example, include in the sidelink terminal information message an information element indicating that the UE122 is playing the role of an intermediate relay UE.

[0157] Furthermore, the information element indicating that UE122 is acting as an intermediate relay UE may be included in the sidelink terminal information message together with the information element indicating that UE122 is acting as a remote UE.

[0158] In addition to or instead of the above, UE122 may include the above-mentioned information elements in the sidelink terminal information message based on its determination of what type of UE to transmit the sidelink terminal information message. For example, based on its determination to transmit the sidelink terminal information message as a remote UE, UE122 may include an information element indicating that it is playing the role of a remote UE in the sidelink terminal information message; for example, based on its determination to transmit the sidelink terminal information message as a relay UE, UE122 may include an information element indicating that it is playing the role of a relay UE in the sidelink terminal information message; for example, based on its determination to transmit the sidelink terminal information message as an intermediate relay UE, UE122 may include an information element indicating that it is playing the role of an intermediate relay UE in the sidelink terminal information message.

[0159] The L2U2N multihop relay setting may also be a setting that indicates that the cell providing the SIB12 supports L2U2N multihop relay operation. The UE122 may transmit the aforementioned sidelink terminal information message to the base station device. The sidelink terminal information message may be an RRC message named SidelinkUEInformation or an RRC message with another name. In this embodiment, the SIB12, which is a system information block containing settings related to the sending and receiving of sidelink communication and / or discovery messages, is used as an example of the use of a system information block, but other system information blocks or RRC messages may be used instead of the SIB12.

[0160] The UE122 may determine that it is acting as a relay UE based on the fact that no threshold information for a relay UE has been set, or in addition to or instead, it may determine that it is acting as a relay UE based on the fact that it has determined that the RSRP measurement result in the cell where the UE122 is camping or in the PCell of the UE122 is within the range of the threshold set by the threshold information. In addition to or instead, the UE122 may determine that it is not acting as a relay UE based on the fact that it has determined that the RSRP measurement result in the cell where the UE122 is camping or in the PCell of the UE122 is outside the range of the threshold set by the threshold information. In addition to or instead, the UE122 may determine that it is acting as a remote UE based on the fact that no threshold information for a remote UE has been set, or in addition to or instead, it may determine that it is acting as a remote UE based on the fact that it has determined that the RSRP measurement result in the cell where the UE122 is camping or in the PCell of the UE122 is within the range of the threshold set by the threshold information, or in addition to or instead, it may determine that it is acting as a remote UE based on the fact that it has determined that the UE122 does not have a serving cell. In addition or alternatively, the UE122 may determine that it does not perform the role of a remote UE based on the determination that the RSRP measurement result in the cell where the UE122 is camped or in the PCell of the UE122 is outside the range of the threshold set by the threshold information. In addition or alternatively, the UE122 may determine that it performs the role of an intermediate UE based on the fact that no threshold information for an intermediate UE has been set, or in addition or alternatively, it may determine that it performs the role of an intermediate UE based on the determination that the RSRP measurement result in the cell where the UE122 is camped or in the PCell of the UE122 is within the range of the threshold set by the threshold information, or in addition or alternatively, it may determine that it performs the role of an intermediate UE based on the determination that it does not perform the role of a relay UE.In addition to or instead of the above, the UE122 may determine that it does not perform the role of an intermediate UE based on the determination that the RSRP measurement result in the cell where the UE122 is camping or in the PCell of the UE122 is outside the range of the threshold set by the threshold information; in addition to or instead of the above, the UE122 may determine that it does not perform the role of an intermediate UE based on the determination that the UE122 will perform the role of a relay UE.

[0161] In one example of this embodiment, the base station equipment can appropriately identify the type of UE that sent the RRC message in a multi-hop U2N relay.

[0162] Furthermore, in the above explanation, expressions such as "to be notified" and "to be pointed out" may be used interchangeably.

[0163] Furthermore, in the above explanation, expressions such as "link," "correspond," and "associate" may be used interchangeably.

[0164] Furthermore, in the above explanation, expressions such as "included," "included," and "was included" may be interchangeable.

[0165] Furthermore, in the above explanation, "the aforementioned..." may be replaced with "the aforementioned...".

[0166] Furthermore, in the above explanation, expressions such as "it has been confirmed that...", "it is set that...", and "it includes..." can be used interchangeably.

[0167] Furthermore, in the examples of processes or process flows described above, some or all of the steps may not be executed. Also, in the examples of processes or process flows described above, the order of the steps may differ. Also, in the examples of processes or process flows described above, some or all of the processes within each step may not be executed. Also, in the examples of processes or process flows described above, the order of the processes within each step may differ. Furthermore, in the above description, "perform B based on the fact that A is true" may be rephrased as "perform B." That is, "performing B" may be performed independently of "being true A."

[0168] Furthermore, in the above explanation, "A may be replaced with B" may include not only replacing A with B, but also replacing B with A. Also, in the above explanation, if it states "C may be D" and "C may be E", it may also include "D may be E". Also, in the above explanation, if it states "F may be G" and "G may be H", it may also include "F may be H".

[0169] Furthermore, in the above explanation, if condition "A" and condition "B" are contradictory, condition "B" may be expressed as an "other" condition of condition "A".

[0170] Furthermore, in the above explanation, "determining whether or not A is true" may also mean "determining that A is true," or "determining that A is not true." "Determining that A is not true" may also mean "not determining that A is true," and "determining that A is true" may also mean "not determining that A is not true."

[0171] The program running in the device according to this embodiment may be a program that controls the Central Processing Unit (CPU), etc., to make the computer function in order to realize the functions of this embodiment. The program or the information handled by the program is temporarily loaded into volatile memory such as Random Access Memory (RAM) during processing, or stored in non-volatile memory such as flash memory or a Hard Disk Drive (HDD), and read, modified, and written by the CPU as needed.

[0172] Furthermore, some parts of the apparatus in the above-described embodiment may be implemented using a computer. In that case, the program for implementing this control function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be loaded into a computer system and executed. The term "computer system" here refers to a computer system built into the apparatus, and includes hardware such as an operating system and peripheral devices. The "computer-readable recording medium" may be any of the following: a semiconductor recording medium, an optical recording medium, a magnetic recording medium, etc.

[0173] Furthermore, "computer-readable recording media" may include those that dynamically hold programs for a short period of time, such as communication lines used when transmitting programs via networks such as the Internet or communication lines such as telephone lines, as well as those that hold programs for a certain period of time, such as volatile memory inside computer systems that act as servers or clients in such cases. In addition, the above-mentioned programs may be for the purpose of realizing some of the functions described above, and may also be programs that can realize the above-mentioned functions in combination with programs already recorded in the computer system.

[0174] Furthermore, each functional block or feature of the apparatus used in the embodiments described above may be implemented or executed by an electrical circuit, typically an integrated circuit or a combination of integrated circuits. Electrical circuits designed to perform the functions described herein may include general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gates or transistor logic, discrete hardware components, or combinations thereof. The general-purpose processor may be a microprocessor, or alternatively, the processor may be a conventional processor, controller, microcontroller, or state machine. The general-purpose processor, or each of the aforementioned circuits, may consist of digital or analog circuits. Also, if advances in semiconductor technology lead to the emergence of integrated circuit technologies that replace current integrated circuits, it may be possible to use integrated circuits based on such technologies.

[0175] It should be noted that this embodiment is not limited to the embodiments described above. Although the embodiments describe an example of a device, this embodiment is not limited to this and can be applied to stationary or non-movable electronic devices installed indoors or outdoors, such as terminal devices or communication devices for AV equipment, kitchen equipment, cleaning and washing machines, air conditioning equipment, office equipment, vending machines, and other household appliances.

[0176] Although this embodiment has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like that do not depart from the gist of this embodiment are also included. Furthermore, this embodiment can be modified in various ways within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of this embodiment. In addition, configurations in which elements described in the above embodiment that produce similar effects are substituted for each other are also included.

[0177] One aspect of the present invention can be used, for example, in communication systems, communication equipment (e.g., mobile phone devices, base station devices, wireless LAN devices, or sensor devices), integrated circuits (e.g., communication chips), or programs.

[0178] 100 ng-eNB 102 gNB 110, 112, 114 Interface 122 UE 200, 700 PHY 202, 702 MAC 204, 704 RLC 206, 706 PDCP 208, 708 RRC 210 PC5-S 310, 710 SDAP 400 Discovery 500, 600 Receiver 502, 602 Processing Unit 504, 604 Transmitter 712 NAS 800 SRAP

Claims

1. A terminal device that communicates with a base station device, comprising a processing unit and a transmitting unit, wherein the processing unit includes an information element indicating that the terminal device is playing the role of an intermediate relay UE in a first message based on its determination that the terminal device is playing the role of an intermediate relay UE, and the transmitting unit transmits the first message to the base station device.

2. A method for a terminal device to communicate with a base station device, comprising the steps of: including an information element in a first message indicating that the terminal device is playing the role of an intermediate relay UE, based on the terminal device's determination to play the role of an intermediate relay UE; and transmitting the first message to the base station device.

3. An integrated circuit mounted on a terminal device that communicates with a base station device, having a function to include in a first message an information element indicating that the terminal device is playing the role of an intermediate relay UE, based on the terminal device's determination to play the role of an intermediate relay UE, and a function to transmit the first message to the base station device.

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