Terminal device, method, and integrated circuit

Abstract

To provide a terminal device, a method, and an integrated circuit that control communication with a base station device using a direct path and a non-direct path.SOLUTION: In a communication system, a terminal device determines whether a signaling radio bearer is set to a non-direct path to a base station device when a radio link failure is detected on a direct path to the base station device. If the terminal device determines that the signaling radio bearer is set to the non-direct path, the terminal device sends, via the signaling radio bearer, information indicating that the radio link failed on the direct path.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a terminal device, a method, and an integrated circuit. [Background technology]

[0002] The 3rd Generation Partnership Project (3GPP), a standardization project for cellular mobile communication systems, is conducting technical studies and formulating standards for cellular mobile communication systems, including radio access, core networks, and services.

[0003] For example, technical studies and standardization of E-UTRA (Evolved Universal Terrestrial Radio Access) have begun in 3GPP as a radio access technology (RAT) for 3.9G and 4G cellular mobile communication systems. 3GPP is currently conducting technical studies and standardization of E-UTRA extension technologies. E-UTRA is also called Long Term Evolution (LTE: registered trademark), and the extension technologies are sometimes called LTE-Advanced (LTE-A) and LTE-Advanced Pro (LTE-A Pro).

[0004] Additionally, 3GPP has begun technical studies and standardization of NR (New Radio, or NR Radio access) as a radio access technology (RAT) for 5th Generation (5G) cellular mobile communication systems. 3GPP is currently conducting technical studies and standardization of NR extension technologies. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] 3GPP TS 38.331 v17.0.0,"Evolved Universal Terrestrial Radio Access (E-UTRA);Radio Resource Control (RRC);Protocol specifications" pp37-1107 [Non-patent document 2] 3GPP TS 38.321 v17.0.0, "NR;Medium Access Control (MAC) protocol specification" pp17-104 [Non-patent document 3] 3GPP TS 38.213 v17.2.0, "NR; Physical layer procedures for control" pp14-20 [Non-patent document 4] 3GPP TS 38.215 v17.1.0, "NR; Physical layer measurements" pp16-18 [Non-Patent Document 5] 3GPP TS 23.304 v17.1.0, "Proximity based Services (ProSe) in the 5G System (5GS)" pp12-97 [Non-patent document 6] 3GPP TS 38.300 v17.0.0, "NR; NR and NG-RAN Overall Description" pp31-170 [Non-Patent Document 7] RP-221262, "Revised WID on NR sidelink relay enhancements" Summary of the Invention [Problem to be solved by the invention]

[0006] 3GPP has been studying a technology called sidelink (SL), which allows terminal devices to communicate directly with each other without going through a core network, as an extension technology of NR, and a technology called UE-to-Network Relay (U2N Relay), which allows terminal devices to communicate with a base station device via a relay terminal device by providing sidelink communications. Furthermore, they have begun studying a technology called multi-path relaying, which allows communication with a base station device using two (or more) paths: a non-direct path for communication with a base station device using U2N Relay, and a direct path for communication with a base station device directly without using U2N Relay.

[0007] One aspect of the present invention has been made in consideration of the above-mentioned circumstances, and one of its objects is to provide a terminal device, a base station device, a communication method, and an integrated circuit that can efficiently perform communication control. [Means for solving the problem]

[0008] In order to achieve the above object, one aspect of the present invention provides the following: That is, one aspect of the present invention provides a terminal device that communicates with a base station device using a direct path and a non-direct path, the terminal device comprising: a processing unit; and a transmission unit; wherein the direct path is a path through which the terminal device communicates directly with the base station device via a Uu interface, and the non-direct path is a path through which the terminal device communicates with the base station device via a relay terminal device; and when a radio link failure is detected on the direct path and a split bearer is not set for a signaling radio bearer, the processing unit determines whether the signaling radio bearer is set for the non-direct path, and when it is determined that the signaling radio bearer is set for the non-direct path, the transmission unit transmits information indicating a radio link failure on the direct path via the signaling radio bearer.

[0009] Another aspect of the present invention is a method for a terminal device to communicate with a base station device using a direct path and a non-direct path, wherein the direct path is a path through which the terminal device communicates directly with the base station device via a Uu interface, and the non-direct path is a path through which the terminal device communicates with the base station device via a relay terminal device, and when a radio link failure is detected on the direct path and a split bearer is not set on a signaling radio bearer, the method determines whether the signaling radio bearer is set on the non-direct path, and when it is determined that the signaling radio bearer is set on the non-direct path, transmits information indicating a radio link failure on the direct path via the signaling radio bearer.

[0010] Another aspect of the present invention is an integrated circuit implemented in a terminal device that communicates with a base station device using a direct path and a non-direct path, wherein the direct path is a path through which the terminal device communicates directly with the base station device via a Uu interface, and the non-direct path is a path through which the terminal device communicates with the base station device via a relay terminal device, and when a radio link failure is detected on the direct path and a split bearer is not set on a signaling radio bearer, the integrated circuit determines whether the signaling radio bearer is set on the non-direct path, and when it is determined that the signaling radio bearer is set on the non-direct path, transmits information indicating a radio link failure on the direct path via the signaling radio bearer.

[0011] These comprehensive or specific aspects may be realized as a system, an apparatus, a method, an integrated circuit, a computer program, or a recording medium, or may be realized as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium. [Effects of the Invention]

[0012] According to one aspect of the present invention, a terminal device, a method, and an integrated circuit can realize efficient communication control processing. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram of a communication system according to an embodiment of the present invention. [Figure 2] FIG. 10 is a diagram illustrating an example of a protocol configuration of a side link according to the present embodiment. [Figure 3] FIG. 10 is a diagram illustrating an example of a protocol configuration of a side link according to the present embodiment. [Figure 4] FIG. 10 is a diagram illustrating an example of a protocol configuration of a side link according to the present embodiment. [Figure 5] FIG. 2 is a diagram illustrating an example of a protocol configuration of a terminal device according to the embodiment. [Figure 6] FIG. 10 is a diagram illustrating an example of a protocol configuration of a sidelink relay according to the embodiment. [Figure 7] FIG. 1 is a diagram illustrating an example of a protocol configuration of a sidelink relay according to the present embodiment. [Figure 8] FIG. 2 is a block diagram showing the configuration of a terminal device according to the embodiment. [Figure 9] FIG. 4 is a diagram illustrating an example of processing performed by a terminal device according to the present embodiment. [Figure 10] FIG. 4 is a diagram illustrating an example of processing performed by a terminal device according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, this embodiment will be described in detail with reference to the drawings.

[0015] In this embodiment, the names of the nodes and entities and the processes in the nodes and entities when the radio access technology is NR will be described, but this embodiment may be applied to other radio access technologies. The names of the nodes and entities in this embodiment may be different names.

[0016] Fig. 1 is a schematic diagram of a communication system according to this embodiment. Note that the functions of each node, radio access technology, core network, interface, etc. described using Fig. 1 are only some of the functions closely related to this embodiment, and the system may have other functions.

[0017] E-UTRA may be a radio access technology. E-UTRA may also be the air interface between the UE 122 and the ng-eNB 100. The air interface 112 between the UE 122 and the ng-eNB 100 may be referred to as the Uu interface. The ng-eNB (ng E-UTRAN Node B) 102 may be an E-UTRA base station device. The ng-eNB 100 may have the E-UTRA protocol described below. The E-UTRA protocol may be composed of the E-UTRA User Plane (UP) protocol described below and the E-UTRA Control Plane (CP) protocol described below. The ng-eNB 100 may terminate the E-UTRA user plane protocol and the E-UTRA control plane protocol for the UE 122. A radio access network composed of eNBs may be referred to as E-UTRAN.

[0018] NR may be a radio access technology. NR may also be an air interface between the UE 122 and the gNB 102. The air interface 112 between the UE 122 and the gNB 102 may be referred to as a Uu interface. The gNB (g Node B) 102 may be an NR base station device. The gNB 102 may have the NR protocol described below. The NR protocol may be composed of an NR user plane (User Plane: UP) protocol described below and an NR control plane (Control Plane: CP) protocol described below. The gNB 102 may terminate the NR user plane protocol and the NR control plane protocol for the UE 122.

[0019] The interface 110 between the ng-eNB 100 and the gNB 102 may be referred to as an Xn interface. The ng-eNB and the gNB may connect to the 5GC via an interface called an NG interface (not shown). The 5GC may be a core network. One or more base station devices may connect to the 5GC via the NG interface.

[0020] A state in which a base station device can be connected via only the Uu interface may be referred to as Inside NG-RAN Coverage or In-Coverage (IC). A state in which a base station device cannot be connected via only the Uu interface may be referred to as Outside NG-RAN Coverage or Out-of-Coverage (OOC). The air interface 114 between UEs 122 may be referred to as a PC5 interface. Communication between UEs 122 via the PC5 interface may be referred to as sidelink (SL) communication.

[0021] In the following description, the ng-eNB 100 and / or the gNB 102 will also be referred to simply as a base station device, and the UE 122 will also be referred to simply as a terminal device or a UE. The PC5 interface will also be referred to simply as PC5, and the Uu interface will also be referred to simply as Uu.

[0022] Sidelink is a technology that enables direct communication between terminal devices, and sidelink transmission and reception on PC5 is performed inside and outside the NG-RAN coverage.

[0023] There are three transmission modes for NR SL communication, and SL communication is performed in one of the transmission modes by a pair of a source Layer-2 identifier (Source Layer-2 ID) and a destination Layer-2 identifier (Destination Layer-2 ID). The source Layer-2 identifier and destination Layer-2 identifier may be referred to as a source L2ID and a destination L2ID, respectively. The three transmission modes are "unicast transmission," "groupcast transmission," and "broadcast transmission."

[0024] Unicast transmission is characterized by (1) support for one PC5-RRC connection between a pair of UEs, (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) radio link failure detection for the PC5-RRC connection.

[0025] Groupcast transmission is characterized by (1) transmitting and receiving user traffic between UEs belonging to a sidelink group, and (2) supporting sidelink HARQ feedback.

[0026] Broadcast transmission is also characterized as (1) transmission and reception of user traffic between UEs on the sidelink.

[0027] 2 and 3 are diagrams illustrating an example of a protocol architecture for NR sidelink communication according to this embodiment. Note that the functions of each protocol described using FIG. 2 and / or FIG. 3 are only some of the functions closely related to this embodiment, and other functions may also be included. Note that in this embodiment, a sidelink (SL) may be a link between terminal devices.

[0028] Figure 2(A) is a diagram of a protocol stack of a control plane (CP) for an SCCH using RRC configured on a PC5 interface. As shown in Figure 2(A), the control plane protocol stack for an SCCH using RRC may be composed of a PHY (Physical layer) 200, which is a radio physical layer, a MAC (Medium Access Control) 202, which is a medium access control layer, a RLC (Radio Link Control) 204, which is a radio link control layer, a PDCP (Packet Data Convergence Protocol) 206, which is a packet data convergence protocol layer, and an RRC (Radio Resource Control) 208, which is a radio resource control layer. Figure 2(B) is a diagram of a protocol stack of a control plane for an SCCH using PC5-S configured on a PC5 interface. As shown in FIG. 2(B), the control plane protocol stack for SCCH using PC5-S may be composed of PHY (Physical layer) 200, which is a wireless physical layer, MAC (Medium Access Control) 202, which is a medium access control layer, RLC (Radio Link Control) 204, which is a radio link control layer, PDCP (Packet Data Convergence Protocol) 206, which is a packet data convergence protocol layer, and PC5-S (PC5 Signalling) 210, which is a PC5 signaling layer.

[0029] Figure 3(A) is a diagram of a protocol stack of a control plane for SBCCH configured on a PC5 interface. As shown in Figure 3(A), the control plane protocol stack for SBCCH may be configured with a PHY (Physical layer) 200, which is a radio physical layer, a MAC (Medium Access Control) 202, which is a medium access control layer, a RLC (Radio Link Control) 204, which is a radio link control layer, and an RRC (Radio Resource Control) 208, which is a radio resource control layer. Figure 3(B) is a diagram of a protocol stack of a user plane (UP) for STCH configured on a PC5 interface. As shown in FIG. 3(B), the control plane protocol stack for the STCH may be composed of a PHY (Physical layer) 200, which is a radio physical layer, a MAC (Medium Access Control) 202, which is a medium access control layer, a RLC (Radio Link Control) 204, which is a radio link control layer, a PDCP (Packet Data Convergence Protocol) 206, which is a packet data convergence protocol layer, and an SDAP (Service Data Adaptation Protocol) 310, which is a service data adaptation protocol layer.

[0030] The AS (Access Stratum) layer may be a layer including some or all of the PHY 200, MAC 202, RLC 204, PDCP 206, SDAP 310, and RRC 208. The PC5-S 210 and Discovery 400 described later may be layers higher than the AS layer.

[0031] 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 respectively refer to 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. Note that when sidelink communication is performed using E-UTRA technology, the SDAP layer may not be required. In order to clarify that it is a protocol for sidelink, for example, PDCP may be expressed as sidelink PDCP, and for other protocols, the term "sidelink" may be added to the beginning to indicate that they are protocols for sidelink.

[0032] In this embodiment, when distinguishing between E-UTRA protocols and NR protocols, 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. 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. When distinguishing between E-UTRA protocols and NR protocols, PHY, MAC, RLC, PDCP, and RRC may be referred to as NR PHY, NR MAC, NR RLC, NR RLC, and NR RRC, respectively. PHY, MAC, RLC, PDCP, and RRC may also be referred to as NR PHY, NR MAC, NR RLC, NR PDCP, and NR RRC, respectively.

[0033] This section describes entities in the AS layer of E-UTRA and / or NR. An entity having some or all of the physical layer functions may be referred to as a PHY entity. An entity having some or all of the MAC layer functions may be referred to as a MAC entity. An entity having some or all of the RLC layer functions may be referred to as an RLC entity. An entity having some or all of the PDCP layer functions may be referred to as a PDCP entity. An entity having some or all of the SDAP layer functions may be referred to as an SDAP entity. An entity having some or all of the RRC layer functions may be referred to as an RRC entity. The PHY entity, MAC entity, RLC entity, PDCP entity, SDAP entity, and RRC entity may be referred to as PHY, MAC, RLC, PDCP, SDAP, and RRC, respectively.

[0034] Note that data provided from MAC, RLC, PDCP, and SDAP to lower layers, and / or 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. Data provided from higher layers to MAC, RLC, PDCP, and SDAP, and / or 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. A segmented RLC SDU may be referred to as an RLC SDU segment.

[0035] Here, the base station apparatus and the terminal apparatus exchange (transmit and receive) signals in a higher layer on the Uu interface. The higher layer may be referred to as the upper layer, and the terms may be interchangeable. For example, the base station apparatus and the terminal apparatus may transmit and receive RRC messages (also referred to as RRC signaling) in a Radio Resource Control (RRC) layer. The base station apparatus and the terminal apparatus may also transmit and receive MAC Control Elements (MAC CEs) in a Medium Access Control (MAC) layer. The RRC layer of the terminal apparatus acquires system information broadcast from the base station apparatus. Here, the RRC messages, system information, and / or MAC control elements are also referred to as higher layer signals (higher layer signaling) or higher layer parameters (higher layer parameters). Each of the parameters included in the higher layer signals received by the terminal apparatus may be referred to as a higher layer parameter. For example, in PHY layer processing, an upper layer means a layer higher than the PHY layer, and therefore may mean one or more of a MAC layer, an RRC layer, an RLC layer, a PDCP layer, an NAS (Non Access Stratum) layer, etc. For example, in MAC layer processing, an upper layer may mean one or more of an RRC layer, an RLC layer, a PDCP layer, an NAS layer, etc.

[0036] Furthermore, base station devices also exchange (transmit and receive) signals in higher layers over the PC5 interface. Terminal devices may transmit and receive RRC messages (also referred to as RRC signaling) in the Radio Resource Control (RRC) layer. Furthermore, base station devices and terminal devices may transmit and receive MAC Control Elements (MAC CEs) in the Medium Access Control (MAC) layer. Here, RRC messages and / or MAC Control Elements are also referred to as higher layer signals (higher layer signaling) or higher layer parameters (higher layer parameters). Each of the parameters included in higher layer signals received by a terminal device may be referred to as a higher layer parameter. For example, in PHY layer processing, the higher layer refers to a layer higher than the PHY layer, and may therefore 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 layer may refer to one or more of the RRC layer, RLC layer, PDCP layer, PC5-S layer, Discovery layer, etc.

[0037] Hereinafter, the meaning of "A is given (provided) by an upper layer" or "A is given (provided) by an upper layer" may mean that an upper layer (mainly an RRC layer, a MAC layer, etc.) of a terminal device receives A from a base station device or another terminal device, and the received A is given (provided) to a physical layer of the terminal device from the upper layer of the terminal device. For example, in a terminal device, "being provided with an upper layer parameter" may mean receiving an upper layer signal from a base station device or another terminal device, and providing an upper layer parameter included in the received upper layer signal from the upper layer of the terminal device to the physical layer of the terminal device. Setting an upper layer parameter in a terminal device may mean that the upper layer parameter is given (provided) to the terminal device. For example, setting an upper layer parameter in a terminal device may mean that the terminal device receives an upper layer signal from a base station device or another terminal device, and setting the received upper layer parameter in the upper layer. However, setting an upper layer parameter in a terminal device may also include setting a default parameter that is given in advance to an upper layer of the terminal device. When describing transmission of an RRC message from a terminal device to a base station device or another terminal device, the expression "submitting a message from the RRC entity of the terminal device to a lower layer" may be used. In the terminal device, "submitting a message to a lower layer" from the RRC entity may mean submitting a message to the PDCP layer. In the terminal device, "submitting a message to a lower layer" from the RRC layer may mean submitting to a PDCP entity corresponding to each SRB, since RRC messages are transmitted using SRBs (SRB0, SRB1, SRB2, SRB3, etc.). When the RRC entity of the terminal device receives an indication from a lower layer, the lower layer may mean one or more of the PHY layer, MAC layer, RLC layer, PDCP layer, etc.

[0038] An example of the function of the PHY will be described. The PHY of a terminal device may have a 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 a higher MAC via a transport channel. The PHY may pass data to the MAC via the transport channel. The PHY may also receive 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.

[0039] Here, the physical channels will be described. The physical channels used for wireless communication between a terminal device and another terminal device may include the following physical channels.

[0040] PSBCH (Physical Sidelink Broadcast CHannel) PSCCH (Physical Sidelink Control CHannel) PSSCH (Physical Sidelink Shared Channel) PSFCH (Physical Sidelink Feedback CHannel)

[0041] The PSBCH may be used to broadcast system information required by the terminal device.

[0042] The PSCCH may be used to indicate resources and other transmission parameters for the PSSCH.

[0043] The PSSCH may be used to transmit data and control information related to HARQ / CSI feedback to other terminal devices.

[0044] The PSFCH may be used to carry HARQ feedback to other terminal devices.

[0045] An example of the MAC function will be described. The MAC may be referred to as a MAC sublayer. The MAC may have the function of mapping various logical channels to corresponding transport channels. A logical channel may be identified by a logical channel identity (or logical channel ID). The MAC may be connected to the higher-level RLC via a logical channel. Depending on the type of information to be transmitted, the logical channel may be divided into a control channel for transmitting control information and a traffic channel for transmitting user information. The MAC may have the function of multiplexing MAC SDUs belonging to one or more different logical channels and providing them to the PHY. The MAC may also have the function of demultiplexing MAC PDUs provided by the PHY and providing them to the higher layer via the logical channel to which each MAC SDU belongs. The MAC may also have the function of performing error correction through HARQ (Hybrid Automatic Repeat reQuest). The MAC may also have the function of reporting scheduling information. The MAC may have the function of prioritizing between terminal devices using dynamic scheduling. The MAC may also have the function of prioritizing between logical channels within one terminal device. The MAC may have the function of prioritizing overlapping resources within one terminal device. The E-UTRA MAC may have the function of identifying Multimedia Broadcast Multicast Services (MBMS). The NR MAC may have the function of identifying Multicast / Broadcast Services (MBS). The MAC may have the function of selecting a transport format.The MAC may have functions such as discontinuous reception (DRX) and / or discontinuous transmission (DTX), a random access (RA) procedure, a power headroom report (PHR) function that notifies information about available transmission power, and a buffer status report (BSR) function that notifies information about the amount of data in the transmission buffer. The NR MAC may have a bandwidth adaptation (BA) function. The MAC PDU format used in the E-UTRA MAC may differ from that used in the NR MAC. The MAC PDU may also include a MAC control element (MAC CE), which is an element for controlling the MAC.

[0046] In addition, the MAC sublayer may provide additional services and functions over the PC5 interface, such as radio resource selection for selecting radio resources for sidelink transmission, filtering of packets received in sidelink communication, priority processing between uplink and sidelink, and reporting of sidelink channel state information (Sidelink CSI).

[0047] This section describes the sidelink (SL) logical channels used in E-UTRA and / or NR, and the mapping between the sidelink logical channels and transport channels.

[0048] The SBCCH (Sidelink Broadcast Control Channel) may be a logical channel for sidelink broadcasting sidelink system information from one terminal device to one or more terminal devices, and may be mapped to the SL-BCH, which is a sidelink transport channel.

[0049] The SCCH (Sidelink Control Channel) may be a sidelink logical channel for transmitting control information such as a PC5-RRC message or a PC5-S message from one terminal device to one or more terminal devices. The SCCH may also be mapped to the SL-SCH, which is a sidelink transport channel.

[0050] The STCH (Sidelink Traffic Control Channel) may be a sidelink logical channel for transmitting user information from one terminal device to one or more terminal devices, and may be mapped to the SL-SCH, which is a sidelink transport channel.

[0051] An example of the RLC function will be described. The RLC may also be called an RLC sublayer. The E-UTRA RLC may have the function of segmenting and / or concatenating data provided by the PDCP in the upper layer and providing it to the lower layer. The E-UTRA RLC may have the function of reassembling and reordering data provided by the lower layer and providing it to the upper layer. The NR RLC may have the function of adding a sequence number independent of the sequence number added by PDCP to data provided by the PDCP in the upper layer. The NR RLC may also have the function of segmenting data provided by PDCP and providing it to the lower layer. The NR RLC may also have the function of reassembling data provided by the lower layer and providing it to the upper layer. The RLC may also have the function of data retransmission and / or retransmission request (Automatic Repeat reQuest: ARQ). RLC may also have the function of performing error correction using ARQ. The control information sent from the receiving side of RLC to the transmitting side to indicate data that needs to be retransmitted in order to perform ARQ may be called a status report. The status report transmission instruction sent from the transmitting side of RLC to the receiving side may be called a poll. RLC may also have the function of detecting data duplication. RLC may also have the function of discarding 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 segmented, and an RLC header does not need to be added. The TM RLC entity is a unidirectional entity and may be configured as a transmitting TM RLC entity or a receiving TM RLC entity.In UM, the UM RLC entity performs functions such as segmenting and / or concatenating data received from a higher layer and adding an RLC header, but does not require data retransmission control. The UM RLC entity may be a unidirectional or bidirectional entity. If the UM RLC entity is a unidirectional entity, it may be configured as a transmitting UM RLC entity or a receiving UM RLC entity. If the UM RLC entity is a bidirectional entity, the UM RRC entity may be configured as a UM RLC entity consisting of a transmitting side and a receiving side. In AM, the UM RLC entity may perform functions such as segmenting and / or concatenating data received from a higher layer, adding an RLC header, and controlling data retransmission. The AM RLC entity is a bidirectional entity and may be configured as an AM RLC consisting of a transmitting side and a receiving side. Note that data provided to a lower layer in TM and / or data provided from a lower layer may be referred to as a TMD PDU. Data provided to a lower layer in UM and / or data provided from a lower layer may be referred to as a UMD PDU. Furthermore, data provided to or from a lower layer in AM may be referred to as an AMD PDU. The RLC PDU format used in E-UTRA RLC may differ from the RLC PDU format used in NR RLC. RLC PDUs may include data RLC PDUs and control RLC PDUs. Data RLC PDUs may be referred to as RLC DATA PDUs (RLC Data PDUs). Control RLC PDUs may be referred to as RLC CONTROL PDUs (RLC Control PDUs).

[0052] In the sidelink, TM may be used for SBCCH, only UM is used for groupcast and broadcast transmission, and UM and AM are available for unicast transmission. In the sidelink, UM for groupcast and broadcast transmission supports only unidirectional transmission.

[0053] An example of PDCP functionality is described below. PDCP may be called a 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 wireless interfaces. The protocol used for IP packet header compression / decompression may be called the ROHC (Robust Header Compression) protocol. The protocol used for Ethernet frame header compression / decompression may be called the EHC (Ethernet (registered trademark) Header Compression) protocol. PDCP may also have a data encryption / decryption function. PDCP may also have data integrity protection / verification functions. PDCP may also have a reordering 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 duplicated data. PDCP entities are bidirectional entities and may consist of a transmitting PDCP entity and a receiving PDCP entity. The PDCP PDU format used in E-UTRA PDCP may differ from that used in NR PDCP. PDCP PDUs may include data PDCP PDUs and control PDCP PDUs. A data PDCP PDU may be called a PDCP DATA PDU (PDCP Data PDU). A control PDCP PDU may be called a PDCP CONTROL PDU (PDCP Control PDU).

[0054] In addition, the following restrictions apply to PDCP functions and services in Sidelink: (1) Out-of-order delivery may only be supported with unicast transmission. (2) Duplication on the PC5 interface is not supported.

[0055] An example of SDAP functionality will be described. SDAP is a service data adaptation protocol layer. In the sidelink, the SDAP may perform mapping between sidelink QoS flows transmitted from a terminal device to another terminal device and sidelink data radio bearers (DRBs). The SDAP may also store mapping rule information. The SDAP may also perform QoS flow ID (QFI) marking. SDAP PDUs may include data SDAP PDUs and control SDAP PDUs. The data SDAP PDU may be called SDAP DATA PDU (SDAP Data PDU). The control SDAP PDU may be called SDAP CONTROL PDU (SDAP Control PDU). In the sidelink, a terminal device may have one SDAP entity for each destination for unicast transmission, groupcast transmission, or broadcast transmission associated with the destination. Also, reflective QoS is not supported on PC5 interfaces.

[0056] An example of RRC functionality will be described. RRC may support services and functions such as the transfer of PC5-RRC messages between peer UEs over the PC5 interface, the maintenance and release of PC5-RRC connections between two UEs, and the detection of sidelink radio link failures for PC5-RRC connections. A PC5-RRC connection is a logical connection between two UEs corresponding to a pair of source L2ID and destination L2ID, and is considered established after the corresponding PC5 unicast link is established. A PC5-RRC connection and a PC5 unicast link have a one-to-one correspondence. A UE may have multiple PC5-RRC connections with one or more UEs for different pairs of source L2ID and destination L2ID. Separate PC5-RRC procedures and messages may be used by a UE to transfer UE capabilities and sidelink configurations to a peer UE. Both peer UEs may exchange their UE capabilities and sidelink configurations with each other using separate bidirectional procedures. The UE releases the PC5-RRC connection if it is not interested in sidelink transmission, if a sidelink radio link failure is detected for the PC5-RRC connection, and if the Layer 2 link release procedure is completed.

[0057] A terminal device capable of sidelink communication may perform discovery. Discovery may be performed in Model A or Model B. Figure 4 shows the protocol stack for the discovery procedure. Mode A uses a single discovery protocol message, while Model B uses 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. The procedures for Model A and Model B in ProSe Direct Discovery are outlined below.

[0058] In Model A, a UE that transmits an announce message may be referred to as an announcing UE, and a UE that monitors the announce message may be referred to as a monitoring UE. The announce message may include information such as a discovery message type, a ProSe Application Code or a ProSe Restricted Code, and a security protection element, and may also include metadata information. The announce message is transmitted using a destination layer-2 ID (L2ID) and a source layer-2 ID (L2ID), and the monitoring UE determines the destination layer-2 ID to receive the announce message. Note that the destination layer-2 ID may be the Layer-2 identifier of the destination UE, and the source layer-2 ID may be the Layer-2 identifier of the source UE. The destination UE may simply be referred to as the destination.

[0059] In Model B, a UE that sends an INVITE message may be referred to as a discoverer UE, and a UE that receives the INVITE message and / or sends a response message to the discoverer UE may be referred to as a discoveree UE. The INVITE message may include information such as a discovery message type, a ProSe Query Code, and a security protection element. The INVITE message is sent using a destination L2 ID and a source L2 ID, and the discoveree UE determines the destination L2 ID to receive the INVITE message. The discoveree UE responding to the INVITE message sends a response message. The response message may include information such as a discovery message type, a ProSe Response Code, and a security protection element, and may also include metadata information. The response message is sent using a source L2 ID, and the destination L2 ID is set to the source L2 ID of the received INVITE message.

[0060] Discovery may include types other than ProSe Direct Discovery, which discovers other UEs for direct communication with them, such as Group Member Discovery, which discovers one or more UEs for intragroup communication using a sidelink, and 5G ProSe UE-to-Network Relay Discovery, which discovers candidate relay UEs for connecting to a network via a relay UE. Note that the above-described discovery is an example of discovery provided by an application called ProSe, but other than the above-described types, different types of discovery may exist 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.

[0061] 4 is a diagram showing an example of a protocol configuration including a discovery protocol according to this embodiment. As shown in FIG. 4, the control plane protocol stack for SBCCH may be composed of a PHY (Physical layer) 200, which is a radio physical layer, a MAC (Medium Access Control) 202, which is a medium access control layer, a RLC (Radio Link Control) 204, which is a radio link control layer, and a Discovery 400, which is a discovery protocol layer. Discovery 400 may be a protocol used to process discovery-related procedures. The interface between UEs performing discovery may be referred to as PC5-D.

[0062] Multiple resource pools for transmitting discovery messages may be configured, or one or more resource pools may be configured exclusively for discovery. If a resource pool dedicated to discovery is configured, the UE may use the resource pool dedicated to discovery as the resource pool for transmitting discovery messages. If a resource pool dedicated to discovery is not configured, the UE may use the resource pool for sidelink communication as the resource pool for transmitting discovery messages. Note that multiple resource pools for sidelink communication and multiple resource pools dedicated to discovery may be configured simultaneously. Each resource pool may be configured by UE-dedicated signaling or may be configured in advance.

[0063] A sidelink signaling radio bearer (SRB) may be configured for each unicast PC5-RRC connection. 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 for establishing 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 over PC5.

[0064] Multi-path relay (also referred to as multi-path relaying) will now be described. Multi-path relay may be a technology in which a terminal device communicates with a base station device using two paths, a direct path and an indirect path. The direct path may be a path in which the terminal device communicates directly with the base station device via a Uu interface. Furthermore, the indirect path may be a path in which the terminal device communicates with the base station device via a relay terminal device. The interface between the terminal device and the relay terminal device may be a PC5 interface, or may be a different interface. Furthermore, the relay terminal device may be a terminal device that plays the role of a U2N Relay UE.

[0065] In multipath relaying, a bearer that is mapped to a direct path may be called a direct bearer, a bearer that is mapped to an indirect path may be called an indirect bearer, and a bearer that is mapped to both a direct path and an indirect path may be called a multi-path split bearer (MP (Multi-path) split bearer) or simply a split bearer.

[0066] In a multi-path split bearer, an RLC channel for the Uu interface and an RLC channel for the indirect path may be established for a PDCP entity of a terminal device having two paths, a direct path and an indirect path. Furthermore, if the interface between the terminal device and the relay terminal device on the indirect path is a PC5 interface, the RLC channel for the indirect path may be an RLC channel for the PC5 interface. When PDCP duplication is established for a multi-path split bearer and activated, the PDCP entity may duplicate a PDCP DATA PDU to be submitted to a lower layer and submit data to both of the multiple RLC channels established for the PDCP entity. A multi-path split bearer may be referred to as a bearer on which a multi-path split bearer is established. Furthermore, a multi-path split bearer may be established as either a data radio bearer or a signaling radio bearer. Furthermore, if PDCP replication is not configured for a bearer for which a split bearer is configured (or if PDCP replication is configured but not activated) and a preferred path is configured, the PDCP DATA PDU may be submitted to the primary RLC entity configured for the preferred path, and if a split secondary RLC entity is configured and the amount of data to be submitted to the primary RLC entity and the split secondary RLC entity is equal to or greater than a threshold, the PDCP DATA PDU may be submitted to either the primary RLC entity or the split secondary RLC entity.

[0067] Here, we will explain a UE-to-Network (U2N) relay used in communication on a non-direct path. A U2N relay may be a function that provides network connectivity for a remote terminal device (Remote UE). A remote terminal device that connects to a network using a U2N relay may be referred to as a U2N Remote UE. A terminal device that provides network connectivity for a U2N Remote UE may be referred to as a U2N relay terminal device (Relay UE) or simply as 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. A U2N relay may be classified into types such as a Layer 2 (L2) U2N relay and a Layer 3 (L3) U2N relay. A remote terminal device in an L2 U2N relay may be particularly referred to as an L2 U2N Remote UE, and a relay terminal device in an L2 U2N relay may be particularly referred to as an L2 U2N Relay UE. Furthermore, the L2 U2N relay may include a Sidelink Relay Adaptation Protocol (SRAP) layer, SRAP 600. Note that SRAP 600 may be simply referred to as SRAP.

[0068] FIG. 6 is a diagram showing an example of a protocol configuration of a control plane (C-plane) including an SRAP layer according to this embodiment. Also, FIG. 7 is a diagram showing an example of a protocol configuration of a user plane (U-plane) including an SRAP layer according to this embodiment. As shown in FIGS. 6 and 7, the SRAP layer may be associated between a Remote UE and a Relay UE, or may be associated between a Relay UE and a gNB 102. Note that the gNB 102 shown in FIGS. 6 and 7 may be an ng-eNB 100. Also, the Remote UE or the Relay UE may be a UE 122.

[0069] Here, the SRAP will be described. The SRAP may be referred to as the SRAP sublayer. The SRAP sublayer may reside above the RLC sublayer for the control plane and user plane of both the PC5 interface and the Uu interface. The SRAP sublayer on the PC5 interface may be used for bearer mapping. In an L2 U2N Relay UE, the SRAP sublayer may include one SRAP entity on the Uu interface and a separate collocated SRAP entity on the PC5 interface. In an L2 U2N Remote UE, the SRAP sublayer may include only one SRAP entity on the PC5 interface. The SRAP entity associated between the Remote UE and the Relay UE via the PC5 interface may be specifically referred to as a PC5-SRAP, and the SRAP entity associated between the Relay UE and the gNB via the Uu interface may be specifically referred to as a Uu-SRAP. Each SRAP entity may have a transmitter and a receiver. On the PC5 interface, a transmitter of the SRAP entity of the L2 U2N Remote UE may be associated with a receiver of the SRAP entity of the L2 U2N Relay UE, and a receiver of the SRAP entity of the L2 U2N Remote UE may be associated with a transmitter of the SRAP entity of the L2 U2N Relay UE. Also, on the Uu interface, a transmitter of the SRAP entity of the L2 U2N Relay UE may be associated with a receiver of the SRAP entity of the gNB102, and a receiver of the SRAP entity of the L2 U2N Relay UE may be associated with a transmitter of the SRAP entity of the gNB102.

[0070] The SRAP entity may also have the functions of forwarding data, determining the UE ID field and bearer ID field of the SRAP header to be added to the data packet, determining the egress link, and determining the egress RLC channel.

[0071] Also, in Figures 6 and 7, a PC5 Relay RLC channel may be established between the Remote UE and the Relay UE, and a Uu Relay RLC channel may be established between the Relay UE and the gNB102.

[0072] Next, a protocol configuration used between a base station device and a terminal device will be described. The protocol used between the base station device and the terminal device may be used in communication performed over the Uu interface between the terminal device and the base station device, i.e., communication over a direct path, communication performed via a relay terminal device set to a non-direct path, and communication performed over the Uu interface between the relay terminal device and the base station device.

[0073] FIG. 5 is a diagram illustrating an example of an NR protocol configuration according to this embodiment. The functions of each protocol described using FIG. 5 are some of the functions closely related to this embodiment, and other functions may also be included. In this embodiment, an uplink (UL) may be a link from a terminal device to a base station device. Also, in this embodiment, a downlink (DL) may be a link from a base station device to a terminal device.

[0074] FIG. 5A is a diagram of the NR control plane (CP) protocol stack. As shown in FIG. 5A, the NR CP protocol may be a protocol between the UE 122 and the gNB 102. That is, the NR CP protocol may be a protocol terminated at the gNB 102 on the network side. As shown in FIG. 5A, the NR control plane protocol stack may be composed of a PHY (Physical layer) 500, a MAC (Medium Access Control) 502, a RLC (Radio Link Control) 504, a PDCP (Packet Data Convergence Protocol) 506, and a RRC (Radio Resource Control) 508. FIG. 5B is a diagram of the NR user plane (UP) protocol stack. As shown in Figure 5(B), the NR UP protocol may be a protocol between the UE 122 and the gNB 102. That is, the NR UP protocol may be a protocol that terminates at the gNB 102 on the network side. As shown in Figure 5(B), the NR user plane protocol stack may be composed of a radio physical layer PHY 500, a medium access control layer MAC 502, a radio link control layer RLC 504, a packet data convergence protocol layer PDCP 506, and a service data adaptation protocol layer SDAP (Service Data Adaptation Protocol) 510.

[0075] The AS (Access Stratum) layer may be a layer that terminates between the UE 122 and the gNB 102. In other words, the AS layer may be a layer that includes some or all of the PHY 500, MAC 502, RLC 504, PDCP 506, and RRC 508. The gNB 102 may also be an ng-eNB 100. Although only the NR protocol is shown, the E-UTRA protocol may also be used. In the E-UTRA protocol, the SDAP 510 may not exist, and the E-UTRA protocol may have some functions that differ from those of the NR protocol.

[0076] In the present 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 respectively refer to 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. Furthermore, SDAP (SDAP layer) may refer to the SDAP (SDAP layer) of the NR protocol.

[0077] In this embodiment, when distinguishing between E-UTRA protocols and NR protocols, the PHY 500, MAC 502, RLC 504, PDCP 506, and RRC 508 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. The PHY 500, MAC 502, RLC 504, PDCP 506, and RRC 508 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. Furthermore, when distinguishing between E-UTRA protocols and NR protocols, PHY 500, MAC 502, RLC 504, PDCP 506, and RRC 508 may be referred to as NR PHY, NR MAC, NR RLC, NR RLC, and NR RRC, respectively. PHY 500, MAC 502, RLC 504, PDCP 506, and RRC 508 may also be referred to as NR PHY, NR MAC, NR RLC, NR PDCP, and NR RRC, respectively.

[0078] This section describes entities in the AS layer of E-UTRA and / or NR. An entity having some or all of the physical layer functions may be referred to as a PHY entity. An entity having some or all of the MAC layer functions may be referred to as a MAC entity. An entity having some or all of the RLC layer functions may be referred to as an RLC entity. An entity having some or all of the PDCP layer functions may be referred to as a PDCP entity. An entity having some or all of the SDAP layer functions may be referred to as an SDAP entity. An entity having some or all of the RRC layer functions may be referred to as an RRC entity. The PHY entity, MAC entity, RLC entity, PDCP entity, SDAP entity, and RRC entity may be referred to as PHY, MAC, RLC, PDCP, SDAP, and RRC, respectively.

[0079] Note that data provided from MAC, RLC, PDCP, and SDAP to lower layers, and / or 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. Data provided from higher layers to MAC, RLC, PDCP, and SDAP, and / or 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. A segmented RLC SDU may be referred to as an RLC SDU segment.

[0080] Here, the base station apparatus and the terminal apparatus exchange (transmit and receive) signals in a higher layer. The higher layer may be referred to as an upper layer, and the terms may be interchangeable. For example, the base station apparatus and the terminal apparatus may transmit and receive RRC messages (also referred to as RRC signaling) in a Radio Resource Control (RRC) layer. The base station apparatus and the terminal apparatus may also transmit and receive MAC control elements in a Medium Access Control (MAC) layer. The RRC layer of the terminal apparatus acquires system information broadcast from the base station apparatus. Here, the RRC messages, system information, and / or MAC control elements are also referred to as higher layer signals (higher layer signaling) or higher layer parameters (higher layer parameters). Each of the parameters included in the higher layer signals received by the terminal apparatus may be referred to as a higher layer parameter. For example, in PHY layer processing, an upper layer means a layer higher than the PHY layer, and therefore may mean one or more of a MAC layer, an RRC layer, an RLC layer, a PDCP layer, an NAS (Non Access Stratum) layer, etc. For example, in MAC layer processing, an upper layer may mean one or more of an RRC layer, an RLC layer, a PDCP layer, an NAS layer, etc.

[0081] Hereinafter, the meaning of "A is given (provided) by an upper layer" or "A is given (provided) by an upper layer" may mean that an upper layer (mainly an RRC layer, a MAC layer, etc.) of a terminal device receives A from a base station device, and the received A is given (provided) to a physical layer of the terminal device from the upper layer of the terminal device. For example, in a terminal device, "being provided with upper layer parameters" may mean receiving an upper layer signal from a base station device, and providing upper layer parameters included in the received upper layer signal 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 given (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 a base station 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 given in advance to the upper layer of the terminal device. When describing 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 a 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 a PDCP layer. In a terminal device, "submitting a message to a lower layer" from an RRC layer may mean submitting to a PDCP entity corresponding to each SRB, since RRC messages are transmitted using SRBs (SRB0, SRB1, SRB2, SRB3, etc.). When the RRC entity of the terminal device receives an indication from a lower layer, the lower layer may mean one or more of a PHY layer, a MAC layer, an RLC layer, a PDCP layer, etc.

[0082] An example of the functions of the PHY will be described. The PHY of the terminal device may have a function to receive data transmitted from the PHY of the base station device via a downlink (DL) physical channel. The PHY of the terminal device may have a function to transmit data to the PHY of the base station device via an uplink (UL) physical channel. The PHY may be connected to a higher MAC via a transport channel. The PHY may pass data to the MAC via the transport channel. The PHY may also be provided with 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.

[0083] Here, the physical channels will be described. The physical channels used for wireless communication between a terminal device and a base station device may include the following physical channels.

[0084] 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)

[0085] The PBCH may be used to broadcast system information required by a terminal device.

[0086] In addition, in NR, the PBCH may be used to broadcast a time index (SSB-Index) within a synchronization signal block (SSB) period.

[0087] The PDCCH may be used to transmit (or carry) downlink control information (DCI) in downlink wireless communication (wireless communication from a base station device to a terminal device). Here, one or more DCIs (which may also be referred to as DCI formats) may be defined for transmitting the downlink control information. That is, a field for the downlink control information may be defined as DCI and mapped to information bits. The PDCCH may be transmitted in PDCCH candidates. The terminal device may monitor a set of PDCCH candidates in a serving cell. Monitoring the set of PDCCH candidates may mean attempting to decode the PDCCH according to a certain DCI format. Furthermore, the terminal device may monitor the PDCCH candidates at configured monitoring occasions in one or more configured control resource sets (CORESETs) configured by search space configuration. The DCI format may be used for scheduling the PUSCH in the serving cell. The PUSCH may be used for transmitting user data, transmitting RRC messages (described later), and the like.

[0088] PDCCH repetition may be operated by using two search space sets that are explicitly linked by a configuration provided by a higher layer (RRC layer). The two linked search space sets may also be associated with a corresponding CORESET. For PDCCH repetition, the two linked search space sets may be configured in the terminal device with the same number of PDCCH candidates. Two PDCCH candidates in the two linked search space sets may be linked by the same candidate index. When PDCCH repetition is scheduled in the terminal device, inter-slot repetition may be allowed, and each repetition may have the same number of control channel elements (CCEs) and coded bits, and the same DCI payload.

[0089] The PUCCH may be used to transmit uplink control information (UCI) in uplink wireless communication (wireless communication from a terminal device to a base station device). Here, the uplink control information may include channel state information (CSI) used to indicate the state of a downlink channel. The uplink control information may also include a scheduling request (SR) used to request an uplink shared channel (UL-SCH) resource. The uplink control information may also include a hybrid automatic repeat reQuest ACKnowledgement (HARQ-ACK).

[0090] The PDSCH may be used to transmit downlink data (DL-SCH: Downlink Shared CHannel) from the MAC layer, and may also be used to transmit system information (SI) and random access responses (RAR) in the downlink.

[0091] The PUSCH may be used to transmit uplink data from the MAC layer (UL-SCH: Uplink Shared CHannel) or HARQ-ACK and / or CSI together with uplink data. The PUSCH may also be used to transmit only CSI, or only HARQ-ACK and CSI. That is, the PUSCH may be used to transmit only UCI. The PDSCH or PUSCH may also be used to transmit RRC messages and MAC CE (described later). Here, in the PDSCH, an RRC message transmitted from a base station apparatus may be signaling common to multiple terminal apparatuses within a cell. The RRC message transmitted from a base station apparatus may also be signaling dedicated to a certain terminal apparatus. That is, terminal apparatus-specific information may be transmitted using signaling dedicated to a certain terminal apparatus. The PUSCH may also be used to transmit UE capabilities in the uplink.

[0092] The PRACH may be used to transmit a random access preamble and may be used to indicate initial connection establishment procedures, handover procedures, connection re-establishment procedures, synchronization (timing adjustment) for uplink transmissions, and requests for UL-SCH resources.

[0093] An example of the MAC function will be described. The MAC may be referred to as a MAC sublayer. The MAC may have the function of mapping various logical channels to corresponding transport channels. The logical channels may be identified by a logical channel identity (or logical channel ID). The MAC may be connected to the higher-level RLC via logical channels. Depending on the type of information to be transmitted, the logical channels may be divided into control channels that transmit control information and traffic channels that transmit user information. The logical channels may also be divided into uplink logical channels and downlink logical channels. The MAC may have the function of multiplexing MAC SDUs belonging to one or more different logical channels and providing them to the PHY. The MAC may also have the function of demultiplexing MAC PDUs provided by the PHY and providing them to the higher layer via the logical channel to which each MAC SDU belongs. The MAC may also have the function of performing error correction through HARQ (Hybrid Automatic Repeat reQuest). The MAC may also have the function of reporting scheduling information. The MAC may also have the function of prioritizing processing between terminal devices using dynamic scheduling. The MAC may also have the function of prioritizing processing between logical channels within one terminal device. The MAC may also have the function of prioritizing processing of overlapping resources within one terminal device. The E-UTRA MAC may have the function of identifying Multimedia Broadcast Multicast Services (MBMS). The NR MAC may also have the function of identifying Multicast / Broadcast Services (MBS). The MAC may have the function of selecting a transport format.The MAC may have functions such as discontinuous reception (DRX) and / or discontinuous transmission (DTX), a random access (RA) procedure, a power headroom report (PHR) function that notifies information about available transmission power, and a buffer status report (BSR) function that notifies information about the amount of data in the transmission buffer. The NR MAC may have a bandwidth adaptation (BA) function. The MAC PDU format used in the E-UTRA MAC may differ from that used in the NR MAC. The MAC PDU may also include a MAC control element (MAC CE), which is an element for controlling the MAC.

[0094] This section describes logical channels for uplink (UL) and / or downlink (DL) used in E-UTRA and / or NR.

[0095] The BCCH (Broadcast Control Channel) may be a downlink logical channel for broadcasting control information such as system information (SI).

[0096] A PCCH (Paging Control Channel) may be a downlink logical channel for carrying paging messages.

[0097] A CCCH (Common Control Channel) may be a logical channel for transmitting control information between a terminal device and a base station device. The CCCH may be used when the terminal device does not have an RRC connection. The CCCH may also be used between a base station device and multiple terminal devices.

[0098] A DCCH (Dedicated Control Channel) may be a logical channel for transmitting dedicated control information bidirectionally, point-to-point, between a terminal device and a base station device. The dedicated control information may be control information dedicated to each terminal device. The DCCH may be used when the terminal device has an RRC connection.

[0099] A DTCH (Dedicated Traffic Channel) 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 dedicated to each terminal device. A DTCH may exist in both uplink and downlink.

[0100] This section describes the mapping of logical channels and transport channels for the uplink in E-UTRA and / or NR.

[0101] The CCCH may be mapped to an uplink shared channel (UL-SCH), which is an uplink transport channel.

[0102] The DCCH may be mapped to an uplink shared channel (UL-SCH), which is an uplink transport channel.

[0103] The DTCH may be mapped to an uplink shared channel (UL-SCH), which is an uplink transport channel.

[0104] This section describes the mapping of logical channels and transport channels for the downlink in E-UTRA and / or NR.

[0105] The BCCH may be mapped to a downlink transport channel, a Broadcast Channel (BCH) and / or a Downlink Shared Channel (DL-SCH).

[0106] The PCCH may be mapped to a PCH (Paging Channel), which is a downlink transport channel.

[0107] The CCCH may be mapped to a DL-SCH (Downlink Shared Channel), which is a downlink transport channel.

[0108] The DCCH may be mapped to a DL-SCH (Downlink Shared Channel), which is a downlink transport channel.

[0109] The DTCH may be mapped to a DL-SCH (Downlink Shared Channel), which is a downlink transport channel.

[0110] An example of the RLC function will be described. The RLC may also be called an RLC sublayer. The E-UTRA RLC may have the function of segmenting and / or concatenating data provided by the PDCP in the upper layer and providing it to the lower layer. The E-UTRA RLC may have the function of reassembling and reordering data provided by the lower layer and providing it to the upper layer. The NR RLC may have the function of adding a sequence number independent of the sequence number added by PDCP to data provided by the PDCP in the upper layer. The NR RLC may also have the function of segmenting data provided by PDCP and providing it to the lower layer. The NR RLC may also have the function of reassembling data provided by the lower layer and providing it to the upper layer. The RLC may also have the function of data retransmission and / or retransmission request (Automatic Repeat reQuest: ARQ). RLC may also have the function of performing error correction using ARQ. The control information sent from the receiving side of RLC to the transmitting side to indicate data that needs to be retransmitted in order to perform ARQ may be called a status report. The status report transmission instruction sent from the transmitting side of RLC to the receiving side may be called a poll. RLC may also have the function of detecting data duplication. RLC may also have the function of discarding 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 segmented, and an RLC header does not need to be added. The TM RLC entity is a unidirectional entity and may be configured as a transmitting TM RLC entity or a receiving TM RLC entity.In UM, the UM RLC entity performs functions such as segmenting and / or concatenating data received from a higher layer and adding an RLC header, but does not require data retransmission control. The UM RLC entity may be a unidirectional or bidirectional entity. If the UM RLC entity is a unidirectional entity, it may be configured as a transmitting UM RLC entity or a receiving UM RLC entity. If the UM RLC entity is a bidirectional entity, the UM RRC entity may be configured as a UM RLC entity consisting of a transmitting side and a receiving side. In AM, the UM RLC entity may perform functions such as segmenting and / or concatenating data received from a higher layer, adding an RLC header, and controlling data retransmission. The AM RLC entity is a bidirectional entity and may be configured as an AM RLC consisting of a transmitting side and a receiving side. Note that data provided to a lower layer in TM and / or data provided from a lower layer may be referred to as a TMD PDU. Data provided to a lower layer in UM and / or data provided from a lower layer may be referred to as a UMD PDU. Furthermore, data provided to or from a lower layer in AM may be referred to as an AMD PDU. The RLC PDU format used in E-UTRA RLC may differ from the RLC PDU format used in NR RLC. RLC PDUs may include data RLC PDUs and control RLC PDUs. Data RLC PDUs may be referred to as RLC DATA PDUs (RLC Data PDUs). Control RLC PDUs may be referred to as RLC CONTROL PDUs (RLC Control PDUs).

[0111] An example of PDCP functionality is described below. PDCP may be called a 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 wireless interfaces. The protocol used for IP packet header compression / decompression may be called the ROHC (Robust Header Compression) protocol. The protocol used for Ethernet frame header compression / decompression may be called the EHC (Ethernet (registered trademark) Header Compression) protocol. PDCP may also have a data encryption / decryption function. PDCP may also have data integrity protection / verification functions. PDCP may also have a reordering 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 duplicated data. PDCP entities are bidirectional entities and may consist of a transmitting PDCP entity and a receiving PDCP entity. The PDCP PDU format used in E-UTRA PDCP may differ from that used in NR PDCP. PDCP PDUs may include data PDCP PDUs and control PDCP PDUs. A data PDCP PDU may be called a PDCP DATA PDU (PDCP Data PDU). A control PDCP PDU may be called a PDCP CONTROL PDU (PDCP Control PDU).

[0112] An example of SDAP functionality will be described. SDAP is a service data adaptation protocol layer. SDAP may have the function of mapping a downlink QoS flow sent from 5GC to a terminal device via a base station device to a data radio bearer (DRB), and / or mapping an uplink QoS flow sent from the terminal device via a base station device to a DRB. SDAP may also have the function of storing mapping rule information. SDAP may also have the function of marking a QoS flow identifier (QoS Flow ID: QFI). SDAP PDUs may include 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). There may be one SDAP entity in a terminal device for each PDU session.

[0113] An example of the functions of the RRC will be described. The RRC may have a broadcast function. The RRC may have a paging function from the 5GC. The RRC may have a paging function from the gNB 102 or the ng-eNB 100. The RRC may also have an RRC connection management function. The RRC may also have a radio bearer control function. The RRC may also have a cell group control function. The RRC may also have a mobility control function. The RRC may also have terminal device measurement reporting and terminal device measurement reporting control functions. The RRC may also have a QoS management function. The RRC may also have a radio link failure detection and recovery function. The RRC may use RRC messages to perform broadcasting, paging, RRC connection management, radio bearer control, cell group control, mobility control, terminal device measurement reporting and terminal device measurement reporting control, QoS management, radio link failure detection and recovery, etc. Note that the RRC messages and parameters used in E-UTRA RRC may be different from the RRC messages and parameters used in NR RRC.

[0114] RRC messages may be sent using the logical channel BCCH, the logical channel PCCH, the logical channel CCCH, or the logical channel DCCH, and RRC messages sent using the DCCH are referred to as dedicated RRC signaling, or RRC signaling.

[0115] The RRC messages sent using the BCCH may include, for example, a Master Information Block (MIB), various types of System Information Blocks (SIBs), or other RRC messages.The RRC messages sent using the PCCH may include, for example, paging messages or other RRC messages.

[0116] RRC messages transmitted in the uplink (UL) direction using the CCCH may include, for example, an RRC setup request message (RRC Setup Request), an RRC resume request message (RRC Resume Request), an RRC reestablishment request message (RRC Reestablishment Request), an RRC system information request message (RRC System Info Request), etc. Also, for example, an RRC connection request message (RRC Connection Request), an RRC connection resume request message (RRC Connection Resume Request), an RRC connection reestablishment request message (RRC Connection Reestablishment Request), etc. Other RRC messages may also be included.

[0117] The RRC message transmitted in the downlink (DL) direction using the CCCH may include, for example, an RRC connection reject message (RRC Connection Reject), an RRC connection setup message (RRC Connection Setup), an RRC connection reestablishment message (RRC Connection Reestablishment Reject), an RRC connection reestablishment reject message (RRC Connection Reestablishment Reject), etc. Also, for example, an RRC reject message (RRC Reject), an RRC setup message (RRC Setup), etc. Also, other RRC messages may be included.

[0118] The RRC signaling sent in the uplink (UL) direction using the 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, a UE Capability Information message, etc. Also, 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, a UE Capability Information message, etc. Also, other RRC signaling may be included.

[0119] The RRC signaling sent in the downlink (DL) direction using the DCCH may include, for example, an RRC connection reconfiguration message, an RRC connection release message, a security mode command message, a UE capability inquiry message, etc. Also, for example, an RRC reconfiguration message, an RRC resume message, an RRC release message, an RRC reestablishment message, a security mode command message, a UE capability inquiry message, etc. Also, other RRC signaling may be included.

[0120] The above-mentioned functions of PHY, MAC, RLC, PDCP, SDAP, and RRC are merely examples, and some or all of the functions may not be implemented. Also, some or all of the functions of each layer may be included in other layers.

[0121] Next, state transitions of the UE 122 in LTE and NR will be described. When the UE 122 connected to EPC or 5GC has an established RRC connection, the UE 122 may be in an RRC_CONNECTED state. The state in which the RRC connection is established may include a state in which the UE 122 holds some or all of the UE context described below. The state in which the RRC connection is established may also include a state in which the UE 122 can transmit and / or receive unicast data. The UE 122 may be in an RRC_INACTIVE state when the RRC connection is suspended. The UE 122 may be in the RRC_INACTIVE state when the UE 122 is connected to 5GC and the RRC connection is suspended. When the UE 122 is neither in the RRC_CONNECTED state nor in the RRC_INACTIVE state, the UE 122 may be in an RRC_IDLE state.

[0122] Note that when UE 122 is connected to the EPC, it does not have the RRC_INACTIVE state, but the E-UTRAN may initiate suspension of the RRC connection. When UE 122 is connected to the EPC, when the RRC connection is suspended, UE 122 may transition to the RRC_IDLE state while retaining the UE AS context and an identifier (resumeIdentity) used for resuming. A layer above the RRC layer of UE 122 (e.g., the NAS layer) may initiate the resumption of the suspended RRC connection when UE 122 retains the UE AS context, the E-UTRAN has permitted resumption of the RRC connection, and UE 122 needs to transition from the RRC_IDLE state to the RRC_CONNECTED state.

[0123] The definition of dormancy may be different for UE 122 connected to EPC 104 and UE 122 connected to 5GC 110. In addition, some or all of the procedures for UE 122 to return from dormancy may be different when UE 122 is connected to EPC (when UE 122 is dormant in RRC_IDLE state) and when UE 122 is connected to 5GC (when UE 122 is dormant in RRC_INACTIVE state).

[0124] The RRC_CONNECTED state, RRC_INACTIVE state, and RRC_IDLE state may be referred to as the connected state (connected mode), the inactive state (inactive mode), and the idle state (idle mode), respectively, or as the RRC connected state (RRC connected mode), the RRC inactive state (RRC inactive mode), and the RRC idle state (RRC idle mode).

[0125] The UE AS context held by the UE 122 may be information including all or some of the following: a current RRC configuration, a current security context, a PDCP state including a ROHC (Robust Header Compression) state, a C-RNTI (Cell Radio Network Temporary Identifier) ​​used in the source PCell, a cell identifier (cellIdentity), and a physical cell identifier of the source PCell. Note that the UE AS context held by one or all of the eNB 102 and the gNB 108 may include the same information as the UE AS context held by the UE 122, or may include information different from the information included in the UE AS context held by the UE 122.

[0126] The security context may be information that includes all or part of the following: encryption keys at the AS level, the Next Hop parameter (NH), the Next Hop Chaining Counter parameter (NCC) used to derive the next hop access key, an identifier for the selected AS level encryption algorithm, and a counter used for replay protection.

[0127] Radio bearers will now be described. When a terminal device communicates with a base station device, a radio connection may be established by establishing a radio bearer (RB) between the terminal device and the base station device. A radio bearer used for CP may be called a signaling radio bearer (SRB). A radio bearer used for UP may be called a data radio bearer (DRB). Each radio bearer may be assigned a radio bearer identity (ID). A radio bearer identifier for an SRB may be called an SRB identity (SRB ID). A radio bearer identifier for a DRB may be called a DRB identity (DRB ID). SRB0 to SRB2 may be defined for the SRB of E-UTRA, or other SRBs may be defined. SRB0 to SRB3 may be defined for the SRB of NR, or other SRBs may 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 the establishment of SRB2. The RRC signaling transmitted and / or received using SRB1 may include piggybacked NAS signaling. The logical channel DCCH may be used for all RRC and NAS signaling transmitted and / or received using SRB1. SRB2 may be an SRB for NAS signaling and RRC signaling including logged measurement information. The logical channel DCCH may be used for all RRC and NAS signaling transmitted and / or received using SRB2. 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 in the terminal device.All RRC and NAS signaling transmitted and / or received using SRB3 may use the logical channel DCCH. Other SRBs may also be provided for other uses. DRBs may be radio bearers for user data. RRC signaling transmitted and / or received using DRBs may use the logical channel DTCH.

[0128] The following describes radio bearers in a terminal device. A radio bearer may include an RLC bearer. An RLC bearer may consist of one or two RLC entities and logical channels. If an RLC bearer has two RLC entities, the RLC entities may be a TM RLC entity and / or a transmitting RLC entity and a receiving RLC entity in a unidirectional UM mode 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 states (such as RRC idle state, RRC connected state, and RRC inactive state). SRB1 may be established and / or configured in the 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 in a terminal device in an RRC connected state with AS security activated by RRC signaling received from a base station device. 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 device side of SRB1 and SRB2 may be placed in the master node. SRB3 may be established and / or configured in a terminal device in an RRC connected state with AS security activated by RRC signaling received from a base station device when a secondary node in EN-DC, NGEN-DC, or NR-DC is added or when the secondary node is changed. 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 the SRB3 may be placed in a secondary node. One or more DRBs may be established and / or configured in a terminal device by RRC signaling received from the base station when the terminal device is in an RRC connected state with AS security activated. A DRB may consist of one PDCP entity and one or more RLC bearers. An RLC bearer of a DRB may consist of an AM or UM RLC entity and a logical channel.

[0129] For an RLC bearer established and / or configured in a cell group configured with E-UTRA, the RLC entity established and / or configured may be an E-UTRA RLC. For an RLC bearer established and / or configured in a cell group configured with NR, the RLC entity established and / or configured may be an NR RLC. When an EN-DC is configured in the terminal device, the PDCP entity established and / or configured for an MN-terminated MCG bearer may be either an E-UTRA PDCP or an NR PDCP. When an EN-DC is configured in the terminal device, the PDCP entity established and / or configured for radio bearers of other bearer types, i.e., MN-terminated split bearers, MN-terminated SCG bearers, SN-terminated MCG bearers, SN-terminated split bearers, and SN-terminated SCG bearers, may be an NR PDCP. When an NGEN-DC, NE-DC, or NR-DC is configured in the terminal device, the PDCP entity established and / or configured for radio bearers of all bearer types may be an NR PDCP.

[0130] In NR, a DRB established and / or configured in a terminal device may be associated with one PDU session. One SDAP entity may be established and / or configured for one PDU session in the terminal device. The SDAP entity, PDCP entity, RLC entity, and logical channels established and / or configured in the terminal device may be established and / or configured by RRC signaling received by the terminal device from the base station device.

[0131] The reference signal received power (RSRP) measured in the sidelink may be, for example, the following RSRP: Furthermore, the following RSRP may be referred to as SL-RSRP. (a) PSBCH RSRP (b) PSSCH RSRP (c) PSCCH RSRP

[0132] The PSBCH-RSRP (PSBCH RSRP) may be defined as a linear average of the power contributions of resource elements transmitting multiple Demodulation Reference Signals (DMRSs) associated with the PSBCH. Furthermore, the PSSCH-RSRP (PSSCH RSRP) may be defined as a linear average of the power contributions of resource elements of antenna ports transmitting multiple DMRSs associated with the PSSCH. In the case of multiple antenna ports, the RSRP values ​​for each antenna port may be summed. The PSCCH-RSRP (PSCCH RSRP) may be defined as a linear average of the power contributions of resource elements transmitting multiple DMRSs associated with the PSCCH. The DMRSs may be used, for example, to demodulate the PSBCH, PSSCH, and PSCCH signals. Furthermore, the terminal device may measure the RSRP (SD-RSRP) of a discovery message using, for example, the power contributions of resource elements transmitting DMRSs associated with the discovery message.

[0133] In addition to the SL-RSRP, the UE 122 may measure the following quantities in the sidelink measurements: (a) Sidelink received signal strength indicator (SL RSSI) (b) Sidelink channel occupancy ratio (SL CR) (c) Sidelink channel busy ratio(SL CBR)

[0134] There are two resource allocation modes for NR sidelink communication: Mode 1, in which the UE performs sidelink transmission using resources scheduled by the base station, and Mode 2, in which the UE automatically selects resources for sidelink transmission. In Mode 1, the UE must be RRC_CONNECTED. In Mode 2, the UE can perform sidelink transmission regardless of the RRC state or whether it is inside or outside NG-RAN. In Mode 2, the UE automatically selects resources available for sidelink transmission from one or more resource pools configured before the sidelink transmission.

[0135] Next, a radio link failure in the sidelink will be described. A terminal device performing sidelink communication may determine that a sidelink radio link failure has been detected if any of the following conditions is satisfied: (a) The sidelink RLC indicates that the maximum number of retransmissions for a particular destination has been reached. (b) The T400 for a particular destination has expired. (c) The MAC entity has notified that the maximum number of consecutive HARQ DTXs for a particular destination has been reached. (d) A consistency check failure is reported by the sidelink PDCP entity for SL-SRB2 or SL-SRB3 for a particular destination.

[0136] Next, we will explain Radio Link Monitoring (RLM) in Uu.

[0137] In the RRC connected state, the terminal device may perform RLM in an active BWP (described later) or a BWP designated as a BWP performing radio link monitoring. RLM may be performed based on a reference signal (e.g., CRS in E-UTRA, SSB / CSI-RS in NR) and a signal quality threshold. The reference signal may include an SSB. The signal quality threshold may be configured by the network or a default threshold may be used. SSB-based RLM may be performed based on an SSB associated with an initial DL BWP (described later). SSB-based RLM may be configured for the initial DL BWP and one or more DL BWPs including the SSB associated with the initial DL BWP. CSI-RS-based RLM may be performed for other DL BWPs.

[0138] In RLM, the terminal device may declare a Radio Link Failure (RLF) based on any of the following criteria (A) to (D) being met: (A) The radio problem timer, which starts based on in-sync and out-of-sync notifications from the PHY, expires. (B) A timer that starts based on a measurement report of a specific measurement identifier being triggered while the radio problem timer is running expires. (C) The random access procedure failed. (D) RLC failure detected

[0139] A terminal device that has declared RLF in the MCG may remain in the RRC connected state, select the best cell, and initiate a re-establishment procedure. Also, if DC is configured, a terminal device that has declared RLF may remain in the RRC connected state and notify the network of RLF.

[0140] The terminal device may be configured with reference signals used for RLM by the network through RRC signaling. A radio link monitoring configuration (RadioLinkMonitoringConfig) may be used for the RRC signaling. The terminal device may perform RLM using one or more reference signals (referred to as RLM-RS) configured by the radio link monitoring configuration. Furthermore, if an RLM-RS is not specified, the terminal device may perform RLM using a default reference signal. The radio link monitoring configuration may be configured in the terminal device for each DL BWP. The radio link monitoring configuration may be configured for the DL BWP of the PCell and / or PSCell. The PHY of the terminal device may notify the higher layer (RRC layer) that it is in sync when the condition for being in sync is met. The PHY of the terminal device may notify the higher layer (RRC, etc.) that it is out of sync when the condition for being out of sync is met.

[0141] The radio link monitoring configuration may include information indicating a monitoring purpose and identifier information indicating a reference signal. For example, the monitoring purpose may include a purpose of monitoring a radio link failure, a purpose of monitoring a beam failure, or both purposes. Furthermore, for example, the identifier information indicating the reference signal may include information indicating an SSB-Index of an SSB of a cell. Furthermore, for example, the identifier information indicating the reference signal may include information indicating an identifier linked to a channel state information reference signal (CSI-RS) configured in the terminal device.

[0142] If the terminal device is not provided with an RLM-RS and is provided with (multiple) TCI states for PDCCH reception including one or more CSI-RS, the terminal device performs some or all of the following (A) to (B). (A) If the activated TCI state for PDCCH reception includes only one reference signal, the reference signal provided in that activated TCI state is used for radio link monitoring. (B) If the activated TCI state for PDCCH reception includes two reference signals, it is expected that the QCL type of one reference signal is set to type D, and the reference signal whose QCL type is set to type D is used for radio link monitoring.

[0143] If multiple downlink BWPs (described later) are configured in a serving cell, the terminal device may perform RLM using a reference signal corresponding to the RLM-RS in the active downlink BWPs (described later). If multiple downlink BWPs (described later) are configured in a serving cell and the active downlink BWPs (described later) do not provide an RLM-RS, the terminal device may perform RLM using reference signals provided in an activated TCI state for receiving a PDCCH in the CORESET of the active downlink BWPs. The terminal device performing RLM may be expressed as the PHY of the terminal device assessing radio link quality. If the measured radio link quality becomes worse than a configured threshold, the PHY may report out-of-sync to a higher layer (such as RRC).

[0144] Based on the above description, various embodiments of the present invention will be described. Note that the above-described processes may be applied to processes that are omitted in the following description.

[0145] Fig. 8 is a block diagram showing the configuration of a terminal device (UE 122) in this embodiment. To avoid complicating the explanation, Fig. 8 shows only the main components closely related to this embodiment.

[0146] 8 includes a receiver 800 that receives control information (SCI, MAC control element, RRC signaling, etc.), discovery messages, information including user data, etc. from other terminal devices, a processor 802 that performs processing according to parameters included in the received control information, etc., and a transmitter 804 that transmits the control information (SCI, MAC control element, RRC signaling, etc.), discovery messages, information including user data, etc. to other terminal devices. The processor 802 may also include some or all of the functions of various layers (e.g., a physical layer, a MAC layer, an RLC layer, a PDCP layer, an SDAP layer, an RRC layer, a PC5-S layer, a discovery layer, and an application layer). That is, the processing unit 802 may include some or all of a physical layer processing unit (PHY processing unit), a MAC layer processing unit (MAC processing unit), an RLC layer processing unit (RLC processing unit), a PDCP layer processing unit (PDCP processing unit), an SDAP processing unit (SDAP processing unit), an RRC layer processing unit (RRC processing unit), a PC5-S layer processing unit (PC5-S processing unit), a Discovery layer processing unit (Discovery processing unit), and an application layer processing unit.

[0147] An example of an embodiment of the present invention will be described with reference to FIG.

[0148] When a UE 122 that communicates with a base station device using a direct path and a non-direct path detects a radio link failure on the direct path, the UE 122 determines the path in step S900, and performs an operation based on the determination in step S902.

[0149] If a split bearer is not configured for the signaling radio bearer (SRB), in step S900, the path determination may be determining whether the signaling radio bearer is configured on a direct path. The determination that the signaling radio bearer is configured on a direct path may be determining that the signaling radio bearer is not configured on a non-direct path, and the determination that the signaling radio bearer is not configured on a direct path may be determining that the signaling radio bearer is configured on a non-direct path. If the UE 122 determines that the signaling radio bearer is configured on a direct path, in step S902, the action may be initiating an RRC reestablishment procedure. Additionally or alternatively, if the UE 122 determines that the signaling radio bearer is configured on a direct path, in step S902, the action may be transmitting first information to a relay terminal device configured on a non-direct path. Transmitting the first information to a relay terminal device set on a non-direct path may be expressed as transmitting the first information by PC5-RRC signaling using a PC5-RRC connection between UE 122 and the relay terminal device, or transmitting the first information using a sidelink signaling radio bearer 3 (SL-SRB3) between UE 122 and the relay terminal device. Furthermore, if it is determined that the signaling radio bearer is not set on a direct path, in step S902, the operation may be transmitting the first information using the signaling radio bearer. The signaling radio bearer may be a bearer for transmitting the first information, or may be SRB1 in addition to or instead of the signaling radio bearer.

[0150] Furthermore, if a split bearer is set for the signaling radio bearer, in step S900, the determination of the path may be a determination of whether some or all of the following conditions are satisfied: (a) PDCP duplication is not configured for the signaling radio bearer. (b) The primary path of the signaling radio bearer is set to a direct path.

[0151] If it is determined that (a) and (b) are satisfied, the action in step S902 may be to set the preferred path to a non-direct path and to transmit the first information using the signaling radio bearer.Also, if it is determined that (a) is not satisfied, the action in step S902 may be to transmit the first information using the signaling radio bearer.Also, if it is determined that (a) is satisfied but (b) is not satisfied, the action in step S902 may be to transmit the first information using the signaling radio bearer.

[0152] The first information may be information indicating a radio link failure of a direct path. The first information may include some or all of the following information: (I-1) Information indicating the type of failure. (I-2) Information indicating measurement results regarding frequencies that the base station device has configured the UE 122 to measure. (I-3) A remote terminal identifier (remote UE ID) set in the UE 122. (I-4) A relay terminal identifier (relay UE ID) set in the relay terminal device.

[0153] FIG. 9 shows another example of an embodiment of the present invention.

[0154] When UE 122, which communicates with a base station device using a direct path and an indirect path, detects a radio link failure on the indirect path, it determines the path in step S900 and performs an operation based on the determination in step S902.

[0155] The UE 122 detecting a radio link failure on a non-direct path may be a case where a sidelink radio link failure is detected on a link between the UE 122 and a relay terminal apparatus set on the non-direct path, or may be a case where the UE 122 receives a notification from the relay terminal apparatus indicating that a radio link failure is detected between the relay terminal apparatus and a base station apparatus. The notification may be not only a notification indicating that a radio link failure is detected between the relay terminal apparatus and the base station apparatus, but also a notification indicating that the relay terminal apparatus has failed to establish or resume Uu RRC, a notification indicating that the relay terminal apparatus will perform reconfiguration with sync, or a notification indicating that the relay terminal apparatus will perform cell reselection.

[0156] If a split bearer is not configured for the signaling radio bearer, in step S900, the path determination may be determining whether the signaling radio bearer is configured on a non-direct path. The determination that the signaling radio bearer is configured on a non-direct path may be determining that the signaling radio bearer is not configured on a direct path, and the determination that the signaling radio bearer is not configured on a non-direct path may be determining that the signaling radio bearer is configured on a direct path. If it is determined in step S902 that the signaling radio bearer is configured on a non-direct path, the action may be initiating an RRC connection reestablishment procedure. Furthermore, if it is determined in step S902 that the signaling radio bearer is not configured on a non-direct path, the action may be transmitting first information via the signaling radio bearer. The signaling radio bearer may be a bearer for transmitting the first information, or may additionally or alternatively be an SRB1.

[0157] Furthermore, if a split bearer is set for the signaling radio bearer, in step S900, the determination of the path may be a determination of whether some or all of the following conditions are satisfied: (a) PDCP duplication is not configured for the signaling radio bearer. (b) The primary path of the signaling radio bearer is set to a non-direct path.

[0158] If it is determined that (a) and (b) are satisfied, the operation in step S902 may be to set the preferred path to a direct path and to transmit the first information using the signaling radio bearer.Also, if it is determined that (a) is not satisfied, the operation in step S902 may be to transmit the first information using the signaling radio bearer.Also, if it is determined that (a) is satisfied but (b) is not satisfied, the operation in step S902 may be to transmit the first information using the signaling radio bearer.

[0159] The first information may be information indicating a radio link failure of a non-direct path. The first information may include some or all of the following information: (I-1) Information indicating the type of failure. (I-2) Information indicating measurement results regarding frequencies that the base station device has configured the UE 122 to measure. (I-3) A remote terminal identifier (remote UE ID) set in the UE 122. (I-4) A relay terminal identifier (relay UE ID) set in the relay terminal device.

[0160] An example of an embodiment of the present invention will be described with reference to FIG.

[0161] A UE 122 communicating with a remote terminal device interprets signaling received from the remote terminal device in step S1000 and performs an action in step S1002.

[0162] In step S1000, the UE 122 determines whether the signaling received from the remote terminal device is first information, and if it determines that the signaling received from the remote terminal device is the first information, the operation in step S1002 may be to forward the first information to the base station device. Also, the UE 122 may be a terminal device that plays the role of a relay terminal device.

[0163] The first information may be information set in a remote terminal device indicating a wireless link failure of a direct path. The first information may include some or all of the following information: (I-1) Information indicating the type of failure. (I-2) Information indicating measurement results regarding frequencies that the base station device has configured the UE 122 to measure. (I-3) An identifier set in the remote terminal device to identify the remote terminal. (I-4) An identifier set in the UE 122 to identify the relay terminal.

[0164] In step S1002, UE122 may transmit an identifier identifying the remote terminal set in the remote terminal device to the base station device together with the first information, and in addition to or instead of that, may transmit an identifier identifying the relay terminal set in UE122 to the base station device together with the first information.

[0165] In each embodiment, the link between the remote terminal device and the relay terminal device may be a link via a PC5 interface, or may be another link having a similar function. The identifier for identifying the remote terminal may be a source L2ID, a destination L2ID, a C-RNTI (Cell-Radio Network Temporary Identifier) ​​set in the remote terminal device, a local identifier set in the L2 U2N Remote UE, or another identifier capable of identifying the remote terminal device. The identifier for identifying the relay terminal may be a source L2ID, a destination L2ID, a C-RNTI set in the relay terminal device, a local identifier set in the L2 U2N Relay UE, or another identifier capable of identifying the remote terminal device.

[0166] In each embodiment, transmitting the first information using a (sidelink) signaling radio bearer may be rephrased as submitting the first information to a lower layer via a (sidelink) signaling radio bearer, or may be rephrased as another expression that achieves a similar function. In each embodiment, the UE 122 transmits the first information using a (sidelink) signaling radio bearer, thereby enabling the UE 122 to transmit the first information to the base station device. The embodiments may be combined with each other, and a combination of the embodiments is also included in the technical scope of the present invention.

[0167] In a multipath relay, a radio link failure may be detected in a direct path and / or an indirect path. According to the exemplary embodiments of the present invention, it becomes possible to notify a base station device that a radio link failure has been detected in any path.

[0168] In the above description, expressions such as "to be notified" and "to be pointed out" may be interchangeable.

[0169] In the above description, expressions such as "link," "associate," and "link" may be interchangeable.

[0170] In addition, in the above description, expressions such as "included," "included," and "was included" may be used interchangeably.

[0171] In the above description, "the above-mentioned" may be replaced with "the above-mentioned."

[0172] In the above description, expressions such as "confirmed to be...", "is set to...", and "includes..." may be interchangeable.

[0173] Furthermore, in each example of processing or each example of processing flow in the above description, some or all of the steps may not be executed. Furthermore, in each example of processing or each example of processing flow in the above description, the order of the steps may be different. Furthermore, in each example of processing or each example of processing flow in the above description, some or all of the processing within each step may not be executed. Furthermore, in each example of processing or each example of processing flow in the above description, the order of the processing within each step may be different. Furthermore, in the above description, "doing B based on A being true" may be rephrased as "doing B." In other words, "doing B" may be executed independently of "A being true."

[0174] In the above explanation, "A may be replaced with B" may mean replacing A with B, as well as replacing B with A. Also, in the above explanation, when it is written that "C may be D" and "C may be E", it may also mean that "D may be E". Also, in the above explanation, when it is written that "F may be G" and "G may be H", it may also mean that "F may be H".

[0175] In the above explanation, if the conditions "A" and "B" are contradictory conditions, the condition "B" may be expressed as the "other" condition of the condition "A."

[0176] A program running on an apparatus according to the present embodiment may be a program that controls a central processing unit (CPU) or the like to cause a computer to function so as to realize the functions of the present embodiment. The program or information handled by the program is temporarily loaded into a volatile memory such as a random access memory (RAM) during processing, or stored in a nonvolatile memory such as a flash memory or a hard disk drive (HDD), and is read, modified, or written by the CPU as necessary.

[0177] Note that a part of the device in the above-described embodiment may be realized by a computer. In this case, a program for realizing this control function may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read and executed by a computer system. The "computer system" here refers to a computer system built into the device, including hardware such as an operating system and peripheral devices. Furthermore, the "computer-readable recording medium" may be any of a semiconductor recording medium, an optical recording medium, a magnetic recording medium, etc.

[0178] Furthermore, the term "computer-readable recording medium" may also include a medium that dynamically stores a program for a short period of time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, or a medium that stores a program for a certain period of time, such as a volatile memory within a computer system that serves as a server or client in such cases. The program may also be one that realizes part of the above-mentioned functions, or one that can realize the above-mentioned functions in combination with a program already stored in the computer system.

[0179] Furthermore, each functional block or feature of the device used in the above-described embodiments may be implemented or performed by an electrical circuit, typically an integrated circuit or multiple integrated circuits. The electrical circuit designed to perform the functions described herein may include a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or a combination 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 be composed of digital circuits or analog circuits. Furthermore, if advances in semiconductor technology result in the emergence of integrated circuit technology that replaces current integrated circuits, integrated circuits based on that technology may also be used.

[0180] It should be noted that the present embodiment is not limited to the above-described embodiment. In the embodiment, an example of a device is described, but the present embodiment is not limited to this, and can be applied to terminal devices or communication devices such as stationary or non-movable electronic devices installed indoors or outdoors, for example, AV equipment, kitchen equipment, cleaning / washing equipment, air conditioning equipment, office equipment, vending machines, and other household appliances.

[0181] Although this embodiment has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment and includes design modifications within the scope of the gist of this embodiment. 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. Furthermore, configurations in which elements described in the above embodiment are substituted with elements that achieve the same effect are also included. [Explanation of symbols]

[0182] 100 ng-eNB 102 gNB 110, 112, 114 Interface 122UE 200 PHY 202 MAC 204 RLC 206 PDCP 208 RRC 210 PC5-S 310 SDAP 400 Discovery 500 PHY 502 MAC 504 RLC 506 PDCP 508 RRC 510 SDAP 600 SRAP 800 Receiver 802 Processing section 804 Transmitter

Claims

1. A terminal device that communicates with a base station device using a direct path and an indirect path, a processing unit; a transmitter unit, The direct path is a path through which the terminal device communicates with the base station device via a Uu interface, The non-direct path is a path through which the terminal device communicates with the base station device via a relay terminal device, When the processing unit detects a radio link failure on the direct path and a split bearer is set on a signaling radio bearer (SRB), the processing unit sets the preferred path to the non-direct path based on the determination that a packet data control protocol (PDCP) duplication is not set on the SRB and that a preferred path of the SRB is set on the direct path, and the transmission unit transmits information indicating a radio link failure on the direct path via the SRB. Terminal device.

2. A method for a terminal device to communicate with a base station device using a direct path and an indirect path, comprising: The direct path is a path through which the terminal device communicates with the base station device via a Uu interface, The non-direct path is a path through which the terminal device communicates with the base station device via a relay terminal device, When a radio link failure is detected on the direct path and a split bearer is set on a signaling radio bearer (SRB), set the preferred path to the non-direct path based on determining that a packet data control protocol (PDCP) duplication is not set on the SRB and that a preferred path of the SRB is set on the direct path, and transmit information indicating a radio link failure on the direct path via the SRB. method.

3. An integrated circuit implemented in a terminal device that communicates with a base station device using a direct path and an indirect path, The direct path is a path through which the terminal device communicates with the base station device via a Uu interface, The non-direct path is a path through which the terminal device communicates with the base station device via a relay terminal device, When a radio link failure is detected on the direct path and a split bearer is set on a signaling radio bearer (SRB), set the preferred path to the non-direct path based on determining that a packet data control protocol (PDCP) duplication is not set on the SRB and that a preferred path of the SRB is set on the direct path, and transmit information indicating a radio link failure on the direct path via the SRB. Integrated circuit.

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