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 detects a radio link failure on a non-direct path to a base station device and determines whether a signaling radio bearer is set to a direct path to the base station if no split bearer is set for the signaling radio bearer. If the terminal device determines that the signaling radio bearer is set to the direct path, the terminal device sends information indicating that the radio link failed on the non-direct path via the signaling radio bearer of 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 currently examining technologies and formulating standards for cellular mobile communication systems, including wireless access, core networks, and services.

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

[0004] In addition, 3GPP has begun technical studies and standardization of NR (New Radio, or NR Radio access) as a radio access technology (Radio Access Technology: RAT) for cellular mobile communication systems for the 5th Generation (5G). Currently, 3GPP is continuing 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] In 3GPP, as an extension technology of NR, a technology called sidelink (SL) in which terminal devices communicate directly with each other without going through a core network has been considered, and a technology called UE-to-Network Relay (U2N Relay) in which a relay terminal device provides communication by sidelink so that the terminal device communicates with a base station device via the relay terminal device has also been considered. Furthermore, a technology called multi-path relaying has been started, which communicates with a base station device using two (or more) paths: a non-direct path for communicating with a base station device using a U2N Relay, and a direct path for communicating with a base station device directly without using a U2N Relay.

[0007] One aspect of the present invention has been made in consideration of the above-mentioned circumstances, and an object of the present invention 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 takes the following measures. That is, one aspect of the present invention is 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, the direct path being a path where the terminal device communicates directly with the base station device via a Uu interface, the non-direct path being a path where the terminal device communicates with the base station device via a relay terminal device, the processing unit determining whether the signaling radio bearer is set on the direct path when a radio link failure is detected on the non-direct path and a split bearer is not set on a signaling radio bearer, and when it is determined that the signaling radio bearer is set on the direct path, the transmission unit transmits information indicating a radio link failure on the non-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 non-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 direct path, and when it is determined that the signaling radio bearer is set on the direct path, transmits information indicating a radio link failure on the non-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 non-direct path and a split bearer is not set on a signaling radio bearer, the integrated circuit performs the function of determining whether the signaling radio bearer is set on the direct path, and when it is determined that the signaling radio bearer is set on the direct path, transmitting information indicating a radio link failure on the non-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. Effect 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 description of the drawings]

[0013] [Figure 1] 1 is a schematic diagram of a communication system according to an embodiment of the present invention. [Diagram 2] FIG. 1 is a diagram illustrating an example of a protocol configuration of a side link according to the present embodiment. [Diagram 3] FIG. 1 is a diagram illustrating an example of a protocol configuration of a side link according to the present embodiment. [Figure 4] FIG. 1 is a diagram illustrating an example of a protocol configuration of a side link according to the present embodiment. [Diagram 5] FIG. 4 is a diagram showing an example of a protocol configuration of a terminal device according to the embodiment; [Figure 6] FIG. 1 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 showing an example of processing of a terminal device according to the embodiment. [Figure 10] FIG. 4 is a diagram showing an example of processing of a terminal device according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, the present 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 are described when the radio access technology is NR, 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 an 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 a Uu interface. The ng-eNB (ng E-UTRAN Node B) 102 may be a base station device of E-UTRA. The ng-eNB 100 may have an E-UTRA protocol, which will be described later. The E-UTRA protocol may be composed of an E-UTRA User Plane (UP) protocol, which will be described later, and an E-UTRA Control Plane (CP) protocol, which will be described later. 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 an 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 an NR protocol, which will be described later. The NR protocol may be composed of an NR user plane (User Plane: UP) protocol, which will be described later, and an NR control plane (Control Plane: CP) protocol, which will be described later. 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 called an Xn interface. The ng-eNB and the gNB may be connected 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 be connected to the 5GC via the NG interface.

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

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

[0022] Sidelink is a technology for 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 the 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 of one PC5-RRC connection between a paired UE; (2) transmission and reception of control information and user traffic between UEs on the sidelink; (3) support for sidelink HARQ feedback; (4) transmit power control on the sidelink; (5) support for RLC AM; and (6) 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] In addition, broadcast transmission can be characterized as (1) transmission and reception of user traffic between UEs on the sidelink.

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

[0028] Fig. 2(A) is a diagram of a protocol stack of a control plane (CP) for SCCH using RRC configured on a PC5 interface. As shown in Fig. 2(A), the control plane protocol stack for SCCH using RRC may be composed of PHY (Physical layer) 200, which is a radio physical layer, MAC (Medium Access Control) 202, 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 RRC (Radio Resource Control) 208, which is a radio resource control layer. Also, Fig. 2(B) is a diagram of a protocol stack of a control plane for 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] Fig. 3(A) is a diagram of a protocol stack of a control plane for SBCCH configured on a PC5 interface. As shown in Fig. 3(A), the control plane protocol stack for SBCCH may be configured 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 an RRC (Radio Resource Control) 208 which is a radio resource control layer. Fig. 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. 3B, the control plane protocol stack for the STCH may be composed of PHY (Physical layer) 200, which is a radio 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 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. Also, 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 be PHY (PHY layer), MAC (MAC layer), RLC (RLC layer), PDCP (PDCP layer), SDAP (SDAP layer), RRC (RRC layer), and PC5-S (PC5-S layer) of the NR sidelink protocol, respectively. In addition, when sidelink communication is performed using the 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 addition, in this embodiment, when distinguishing between the E-UTRA protocol and the NR protocol, PHY, MAC, RLC, PDCP, and RRC may be referred to as PHY for E-UTRA or PHY for LTE, MAC for E-UTRA or MAC for LTE, RLC for E-UTRA or RLC for LTE, PDCP for E-UTRA or PDCP for LTE, and RRC for E-UTRA or RRC for LTE, respectively. Also, PHY, MAC, RLC, PDCP, and RRC may be described as E-UTRA PHY or LTE PHY, E-UTRA MAC or LTE MAC, E-UTRA RLC or RLC for LTE, E-UTRA PDCP or LTE PDCP, and E-UTRA RRC or RRC for LTE, respectively. Also, when distinguishing between the E-UTRA protocol and the NR protocol, PHY, MAC, RLC, PDCP, and RRC may be referred to as PHY for NR, MAC for NR, RLC for NR, RLC for NR, and RRC for NR, 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] The following 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 called MAC PDU (Protocol Data Unit), RLC PDU, PDCP PDU, and SDAP PDU, respectively. Also, 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 called MAC SDU (Service Data Unit), RLC SDU, PDCP SDU, and SDAP SDU, respectively. Also, a segmented RLC SDU may be called an RLC SDU segment.

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

[0036] Moreover, base station devices also exchange (transmit and receive) signals in a higher layer on the PC5 interface. Terminal devices may transmit and receive RRC messages (also referred to as RRC signaling) in a Radio Resource Control (RRC) layer. Furthermore, a base station device and a terminal device may transmit and receive MAC Control Elements (MAC CEs) in a Medium Access Control (MAC) layer. Here, an RRC message and / or a MAC control element are also referred to as a higher layer signal (higher layer signaling) or a higher layer parameter (higher layer parameter). Each of the parameters included in a higher layer signal received by a terminal device may be referred to as a higher layer parameter. For example, in the processing of the PHY layer, a higher layer means a higher layer as viewed from the PHY layer, and may mean one or more of a MAC layer, an RRC layer, an RLC layer, a PDCP layer, a PC5-S layer, a Discovery layer, and the like. For example, in MAC layer processing, the higher layer may mean one or more of the RRC layer, the RLC layer, the PDCP layer, the PC5-S layer, the Discovery layer, and the like.

[0037] Hereinafter, the meaning of "A is given (provided) by the upper layer" or "A is given (provided) by the upper layer" may mean that the upper layer (mainly the RRC layer, the MAC layer, etc.) of the terminal device receives A from the base station device or another terminal device, and the received A is given (provided) to the 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 or another terminal device, and providing the upper layer parameters included in the received upper layer signal to the physical layer of the terminal device from the upper 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 sets the received upper layer parameter in the upper layer. However, setting an upper layer parameter in a terminal device may include setting a default parameter that is given in advance to the upper layer of the terminal device. When describing the transmission of an RRC message from a terminal device to a base station device 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 be provided with data from the MAC via the transport channel. In the PHY, a Radio Network Temporary Identifier (RNTI) may be used to identify various control information.

[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 a 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 regarding 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 functions of the MAC will be described. The MAC may be called a MAC sublayer. The MAC may have a 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 upper RLC via a logical channel. The logical channels may be divided into a control channel for transmitting control information and a traffic channel for transmitting user information depending on the type of information to be transmitted. The MAC may have a function of multiplexing MAC SDUs belonging to one or more different logical channels and providing them to the PHY. The MAC may also have a function of demultiplexing MAC PDUs provided from the PHY and providing them to the upper layer via the logical channel to which each MAC SDU belongs. The MAC may also have a function of performing error correction through HARQ (Hybrid Automatic Repeat reQuest). The MAC may also have a function of reporting scheduling information. The MAC may have a function to perform priority processing between terminal devices using dynamic scheduling. The MAC may also have a function to perform priority processing between logical channels within one terminal device. The MAC may have a function to perform priority processing of overlapping resources within one terminal device. The E-UTRA MAC may have a function to identify Multimedia Broadcast Multicast Services (MBMS). The NR MAC may have a function to identify Multicast / Broadcast Services (MBS). The MAC may have a function to select a transport format.The MAC may have a function of performing discontinuous reception (DRX) and / or discontinuous transmission (DTX), a function of executing a random access (RA) procedure, a power headroom report (PHR) function for notifying information on available transmission power, a buffer status report (BSR) function for notifying information on the amount of data in the transmission buffer, and the like. The NR MAC may have a bandwidth adaptation (BA) function. The MAC PDU format used in the E-UTRA MAC may differ from the MAC PDU format used in the NR MAC. The MAC PDU may include a MAC control element (MAC CE), which is an element for performing control in the MAC.

[0046] In addition, the MAC sublayer may provide additional services and functions on 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 for broadcasting sidelink system information from one terminal device to one or more terminal devices. The SBCCH may be mapped to the SL-BCH, which is a sidelink transport channel.

[0049] The SCCH (Sidelink Control Channel) may be a logical channel for sidelink 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 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. The STCH may be mapped to the SL-SCH, which is a sidelink transport channel.

[0051] An example of the function of the RLC will be described. The RLC may be called an RLC sublayer. The E-UTRA RLC may have a function of segmenting and / or concatenating data provided from the PDCP of the upper layer and providing it to a lower layer. The E-UTRA RLC may have a function of reassembling and reordering data provided from the lower layer and providing it to the upper layer. The NR RLC may have a function of adding a sequence number independent of the sequence number added by the PDCP to data provided from the PDCP of the upper layer. The NR RLC may also have a function of segmenting data provided from the PDCP and providing it to the lower layer. The NR RLC may also have a function of reassembling data provided from the lower layer and providing it to the upper layer. The RLC may also have a function of retransmitting data and / or a function of requesting retransmission (Automatic Repeat reQuest: ARQ). RLC may also have a function for performing error correction by ARQ. The control information, which is sent from the receiving side of RLC to the transmitting side to perform ARQ and indicates the data that needs to be retransmitted, may be called a status report. The status report transmission instruction, which is sent from the transmitting side of RLC to the receiving side, may be called a poll. RLC may also have a function for detecting data duplication. RLC may also have a function for 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 divided, and an RLC header does not need to be added. The TM RLC entity is a uni-directional entity and may be configured as a transmitting TM RLC entity or a receiving TM RLC entity.In UM, the division and / or concatenation of data received from a higher layer, the addition of an RLC header, etc. are performed, but the retransmission control of data is not required. The UM RLC entity may be a unidirectional entity or a bi-directional entity. If the UM RLC entity is a unidirectional entity, the UM RLC entity may be configured as a transmitting UM RLC entity or a receiving UM RLC entity. If the UM RLC entity is a bi-directional 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 division and / or concatenation of data received from a higher layer, the addition of an RLC header, the retransmission control of data, etc. are performed. The AM RLC entity is a bi-directional 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 called a TMD PDU. Also, data provided to a lower layer in UM and / or data provided from a lower layer may be called a UMD PDU. Data provided to a lower layer in AM or data provided from a lower layer may be called 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 called RLC DATA PDUs (RLC Data PDUs). Control RLC PDUs may be called RLC CONTROL PDUs (RLC Control PDUs).

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

[0053] An example of the function of PDCP will be described. PDCP may be called a PDCP sublayer. PDCP may have a function of 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 sections. A protocol used for header compression / decompression of IP packets may be called ROHC (Robust Header Compression) protocol. A protocol used for header compression / decompression of Ethernet frames may be called EHC (Ethernet (registered trademark) Header Compression) protocol. PDCP may also have a function of data encryption / decryption. PDCP may also have a function of data integrity protection / integrity verification. PDCP may also have a re-ordering function. PDCP may also have a function of retransmitting PDCP SDUs. PDCP may also have a function of discarding data using a discard timer. PDCP may also have a duplication function. PDCP may also have a function to discard duplicated data. The PDCP entity is a bidirectional entity and may be composed of a transmitting PDCP entity and a receiving PDCP entity. The PDCP PDU format used in E-UTRA PDCP may differ from the PDCP PDU format used in NR PDCP. PDCP PDUs may include data PDCP PDUs and control PDCP PDUs. The data PDCP PDU may be called PDCP DATA PDU (PDCP Data PDU). The control PDCP PDU may be called 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 the function of the SDAP will be described. The SDAP is a service data adaptation protocol layer. In the sidelink, the SDAP may have a function of mapping a sidelink QoS flow sent from a terminal device to another terminal device with a sidelink data radio bearer (DRB). The SDAP may also have a function of storing mapping rule information. The SDAP may also have a function of marking a QoS flow identifier (QoS Flow ID: QFI). The SDAP PDU may include a data SDAP PDU and a control SDAP PDU. The data SDAP PDU may be called an SDAP DATA PDU (SDAP Data PDU). The control SDAP PDU may be called an SDAP CONTROL PDU (SDAP Control PDU). In the sidelink, the SDAP entity of the terminal device may exist for each destination for any of unicast transmission, groupcast transmission, and broadcast transmission associated with the destination. Additionally, reflective QoS is not supported on PC5 interfaces.

[0056] An example of the functionality of RRC will be described. RRC may support services and functions such as transfer of PC5-RRC messages between peer UEs on the PC5 interface, maintenance and release of PC5-RRC connection between two UEs, and detection of sidelink radio link failure for PC5-RRC connection. A PC5-RRC connection is a logical connection between two UEs corresponding to a pair of source L2ID and destination L2ID, and is considered to be established after the corresponding PC5 unicast link is established. There is a one-to-one correspondence between the PC5-RRC connection and the PC5 unicast link. A UE may have multiple PC5-RRC connections to one or multiple UEs for different pairs of source L2ID and destination L2ID. Separate PC5-RRC procedures and messages may be used by the UE to transfer UE capabilities and sidelink configuration to the peer UE. Both peer UEs may also exchange their UE capabilities and sidelink configuration with each other using separate bidirectional procedures. The UE releases the PC5-RRC connection if there is no interest 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 in the discovery procedure. Mode A may use a single discovery protocol message, and Model B may use two discovery protocol messages. The single discovery protocol message in Model A may be an Announcement message, and the discovery protocol messages in Model B may be a Solicitation message and a Response message. Below is an overview of the procedures of Model A and Model B in ProSe Direct Discovery.

[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 additionally include metadata information. The announce message is transmitted using a destination layer-2 ID (D2ID) and a source layer-2 ID (S2ID), and the monitoring UE determines a destination layer-2 ID to receive the announce message. The destination layer-2 ID may be a layer-2 identifier of the destination UE, and the source layer-2 ID may be a layer-2 identifier of the source UE. The destination UE may simply be referred to as a destination.

[0059] In Model B, a UE that sends an invitation message may be referred to as a discoverer UE, and a UE that receives the invitation message and / or sends a response message to the discoverer UE may be referred to as a discoveree UE. The invitation message may include information such as a discovery message type, a ProSe Query Code, and a security protection element. The invitation message is sent using a destination L2ID and a source L2ID, and the discoveree UE determines a destination L2ID to receive the invitation message. In addition, the discoveree UE responding to the invitation 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 additionally include metadata information. The response message is sent using a source L2ID, and the destination L2ID is set to the source L2ID of the received invitation message.

[0060] Discovery may include types other than ProSe Direct Discovery, which discovers other UEs to communicate directly with other UEs, and may include Group member Discovery, which discovers one or more UEs to communicate within a group using a sidelink, and 5G ProSe UE-to-Network Relay Discovery, which discovers candidate relay UEs to connect to a network via a relay UE. The above-mentioned discovery is an example of discovery provided by an application called ProSe, but in addition to the above-mentioned types, there may be different types of discovery depending on the application or service that performs sidelink communication. Also, the information included in the discovery protocol message may differ depending on the type of discovery, and an additional message may be transmitted to transmit additional information.

[0061] FIG. 4 is a diagram of 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 PHY (Physical layer) 200, which is a radio 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, and Discovery 400, which is a discovery protocol layer. Discovery 400 may be a protocol used to process procedures related to discovery. In addition, the interface between UEs performing discovery may be referred to as PC5-D.

[0062] A plurality of resource pools for transmitting discovery messages may be configured, or one or a plurality of resource pools may be configured exclusively for discovery. When a resource pool dedicated to discovery is configured, the UE may use the resource pool dedicated to discovery as a resource pool for transmitting discovery messages, and when a resource pool dedicated to discovery is not configured, the UE may use a resource pool for sidelink communication as a resource pool for transmitting discovery messages. Note that a plurality of resource pools for sidelink communication and a resource pool dedicated to discovery may be configured at the same time. 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 a PC5-S message before PC5-S security is established may be referred to as SL-SRB0. A sidelink SRB used to transmit a PC5-S message for establishing PC5-S security may be referred to as SL-SRB1. A sidelink SRB used to transmit a protected PC5-S message after PC5-S security is established may be referred to as SL-SRB2. A sidelink SRB used to transmit a 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. The PC5-RRC signaling may be RRC signaling between UEs transmitted and received on PC5.

[0064] Multi-path relay (or Multi-path relaying) will be described. Multi-path relaying 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. 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 a different interface. The relay terminal device may be a terminal device that plays the role of a U2N Relay UE.

[0065] In multi-path 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 direct and indirect paths may be called a multi-path split bearer (MP) or simply a split bearer.

[0066] In the multi-path split bearer, an RLC channel for the Uu interface and an RLC channel for the non-direct path may be set for a PDCP entity of a terminal device having two paths, a direct path and a non-direct path. Also, when an interface between a terminal device and a relay terminal device in the non-direct path is a PC5 interface, the RLC channel for the non-direct path may be an RLC channel for the PC5 interface. When PDCP duplication is set for the multi-path split bearer and PDCP duplication is 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 set for the PDCP entity. The multi-path split bearer may be referred to as a bearer on which the multi-path split bearer is set. Also, the multi-path split bearer may be set for both a data radio bearer and a signaling radio bearer. In addition, if PDCP replication is not configured for a bearer for which a split bearer is configured (or PDCP replication is configured but not activated) and a preferred path is configured, the PDCP DATA PDU may be submitted to a 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, a UE-to-Network (U2N) relay used in communication in a non-direct path will be described. The U2N relay may be a function that provides connectivity to a network 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 connectivity to a network 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). The U2N Relay UE may use a Uu interface for communication with a base station device, or may use a PC5 interface for communication with a U2N Remote UE. The U2N relay may be of a type 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, in the L2 U2N relay, there may be a Sidelink Relay Adaptation Protocol (SRAP) layer, SRAP 600. Note that the SRAP 600 may simply be expressed as a SRAP.

[0068] FIG. 6 is a diagram of an example of a protocol configuration of a control plane (C-plane) including a SRAP layer according to the present embodiment. FIG. 7 is a diagram of an example of a protocol configuration of a user plane (U-plane) including a SRAP layer according to the present embodiment. As shown in FIG. 6 and FIG. 7, the SRAP layer may be associated between a Remote UE and a Relay UE, and may be associated between a Relay UE and a gNB 102. Note that the gNB 102 shown in FIG. 6 and FIG. 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 called a SRAP sublayer. The SRAP sublayer may exist above the RLC sublayer for the control plane and the user plane of both the PC5 interface and the Uu interface. The SRAP sublayer on the PC5 may be used for bearer mapping purposes. 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 a function of forwarding data, a function of determining the UE ID field and the bearer ID field of the SRAP header to be added to the data packet, a function of determining an egress link, and a function of determining an 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 gNB102.

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

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

[0074] FIG. 5(A) is a diagram of an NR control plane (CP) protocol stack. As shown in FIG. 5(A), 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 that terminates at the gNB 102 on the network side. As shown in FIG. 5(A), 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 Packet Data Convergence Protocol (PDCP) 506, and a Radio Resource Control (RRC) 508. Also, FIG. 5(B) is a diagram of an NR user plane (UP) protocol stack. As shown in FIG. 5B, 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 FIG. 5B, 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, the MAC 502, the RLC 504, the PDCP 506, and the RRC 508. The gNB 102 may be an ng-eNB 100. Although only the NR protocol is shown, the E-UTRA protocol may be used. In the E-UTRA protocol, the SDAP 510 may not exist, and the E-UTRA protocol may have a function that is partially different from that of the NR protocol.

[0076] In the present embodiment, the E-UTRA protocol and the NR protocol may not be distinguished from each other, and the terms PHY (PHY layer), MAC (MAC layer), RLC (RLC layer), PDCP (PDCP layer), and RRC (RRC layer) may be used. In this case, PHY (PHY layer), MAC (MAC layer), RLC (RLC layer), PDCP (PDCP layer), and RRC (RRC layer) may be the PHY (PHY layer), MAC (MAC layer), RLC (RLC layer), PDCP (PDCP layer), and RRC (RRC layer) of the E-UTRA protocol, and may be the PHY (PHY layer), MAC (MAC layer), RLC (RLC layer), PDCP (PDCP layer), and RRC (RRC layer) of the NR protocol. In addition, SDAP (SDAP layer) may be the SDAP (SDAP layer) of the NR protocol.

[0077] In addition, in this embodiment, when distinguishing between the E-UTRA protocol and the NR protocol, the PHY 500, the MAC 502, the RLC 504, the PDCP 506, and the RRC 508 may be referred to as the PHY for E-UTRA or the PHY for LTE, the MAC for E-UTRA or the MAC for LTE, the RLC for E-UTRA or the RLC for LTE, the PDCP for E-UTRA or the PDCP for LTE, and the RRC for E-UTRA or the RRC for LTE, respectively. The PHY 500, the MAC 502, the RLC 504, the PDCP 506, and the RRC 508 may be referred to as the E-UTRA PHY or the LTE PHY, the E-UTRA MAC or the LTE MAC, the E-UTRA RLC or the LTE RLC, the E-UTRA PDCP or the LTE PDCP, and the E-UTRA RRC or the 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 PHY for NR, MAC for NR, RLC for NR, RLC for NR, and RRC for NR, respectively. Also, PHY 500, MAC 502, RLC 504, PDCP 506, and RRC 508 may be referred to as NR PHY, NR MAC, NR RLC, NR PDCP, and NR RRC, respectively.

[0078] The following 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 called MAC PDU (Protocol Data Unit), RLC PDU, PDCP PDU, and SDAP PDU, respectively. Also, 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 called MAC SDU (Service Data Unit), RLC SDU, PDCP SDU, and SDAP SDU, respectively. Also, a segmented RLC SDU may be called an RLC SDU segment.

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

[0081] Hereinafter, the meaning of "A is given (provided) by the upper layer" or "A is given (provided) by the upper layer" may mean that the upper layer (mainly the RRC layer, the MAC layer, etc.) of the terminal device receives A from the base station device, and the received A is given (provided) to the physical layer of the terminal device from the upper layer of the terminal device. For example, in a terminal device, "upper layer parameters are provided" may mean that an upper layer signal is received from the base station device, and the upper layer parameters included in the received upper layer signal are provided to the physical layer of the terminal device from the upper layer of the terminal device. Setting of upper layer parameters in the terminal device may mean that the upper layer parameters are given (provided) to the terminal device. For example, setting of upper layer parameters in the terminal device may mean that the terminal device receives an upper layer signal from the base station device, and the received upper layer parameters are set in the upper layer. However, setting of upper layer parameters in the terminal device may include setting of default parameters that are given in advance to the upper layer of the terminal device. When describing transmission of an RRC message from the terminal device to the base station device, an expression of submitting a message from the RRC entity of the terminal device to a lower layer (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, the MAC layer, the RLC layer, the PDCP layer, etc.

[0082] An example of the function of the PHY will be described. The PHY of the terminal device may have a function of receiving 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 of transmitting 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, a Radio Network Temporary Identifier (RNTI) 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 period of a synchronization signal block (SSB).

[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 be referred to as DCI formats) may be defined for the transmission of the downlink control information. That is, a field for the downlink control information may be defined as a 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 a set of PDCCH candidates may mean attempting to decode the PDCCH according to a certain DCI format. In addition, the terminal device may monitor the PDCCH candidates in 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 an RRC message to be 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. The two PDCCH candidates present 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. In addition, the PDSCH may be used to transmit system information (SI: System Information) and random access response (RAR: Random Access Response) in the downlink.

[0091] The PUSCH may be used to transmit HARQ-ACK and / or CSI together with uplink data (UL-SCH: Uplink Shared CHannel) from the MAC layer or uplink data. The PUSCH may 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 be used to transmit an RRC message and MAC CE, which will be described later. Here, in the PDSCH, an RRC message transmitted from a base station device may be common signaling for a plurality of terminal devices in a cell. The RRC message transmitted from a base station device may be dedicated signaling for a certain terminal device. That is, terminal device-specific (UE specific) information may be transmitted using dedicated signaling for a certain terminal device. The PUSCH may be used to transmit UE capability 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 function of the MAC will be described. The MAC may be called a MAC sublayer. The MAC may have a 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 upper RLC via a logical channel. The logical channels may be divided into a control channel for transmitting control information and a traffic channel for transmitting user information according to the type of information to be transmitted. The logical channels may also be divided into an uplink logical channel and a downlink logical channel. The MAC may have a function of multiplexing MAC SDUs belonging to one or more different logical channels and providing them to the PHY. The MAC may also have a function of demultiplexing MAC PDUs provided by the PHY and providing them to a higher layer via the logical channel to which each MAC SDU belongs. The MAC may also have a function of performing error correction through HARQ (Hybrid Automatic Repeat reQuest). The MAC may also have a function to report scheduling information. The MAC may have a function to perform priority processing between terminal devices using dynamic scheduling. The MAC may also have a function to perform priority processing between logical channels within one terminal device. The MAC may have a function to perform priority processing of overlapping resources within one terminal device. The E-UTRA MAC may have a function to identify Multimedia Broadcast Multicast Services (MBMS). The NR MAC may have a function to identify Multicast / Broadcast Services (MBS). The MAC may have a function to select a transport format.The MAC may have a function of performing discontinuous reception (DRX) and / or discontinuous transmission (DTX), a function of executing a random access (RA) procedure, a power headroom report (PHR) function for notifying information on available transmission power, a buffer status report (BSR) function for notifying information on the amount of data in the transmission buffer, and the like. The NR MAC may have a bandwidth adaptation (BA) function. The MAC PDU format used in the E-UTRA MAC may differ from the MAC PDU format used in the NR MAC. The MAC PDU may include a MAC control element (MAC CE), which is an element for performing control in the MAC.

[0094] This section describes logical channels for the 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 Paging Control Channel (PCCH) may be a downlink logical channel for carrying paging messages.

[0097] A Common Control Channel (CCCH) 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 in a point-to-point bi-directional manner 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 Dedicated Traffic Channel (DTCH) may be a logical channel for transmitting user data point-to-point between a terminal device and a base station device. A DTCH may be a logical channel for transmitting dedicated user data. The dedicated user data may be user data dedicated to each terminal device. A DTCH may exist in both uplink and downlink.

[0100] This article 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 article 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 Downlink Shared Channel (DL-SCH), which is a downlink transport channel.

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

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

[0110] An example of the function of the RLC will be described. The RLC may be called an RLC sublayer. The E-UTRA RLC may have a function of segmenting and / or concatenating data provided from the PDCP of the upper layer and providing it to a lower layer. The E-UTRA RLC may have a function of reassembling and reordering data provided from the lower layer and providing it to the upper layer. The NR RLC may have a function of adding a sequence number independent of the sequence number added by the PDCP to data provided from the PDCP of the upper layer. The NR RLC may also have a function of segmenting data provided from the PDCP and providing it to the lower layer. The NR RLC may also have a function of reassembling data provided from the lower layer and providing it to the upper layer. The RLC may also have a function of retransmitting data and / or a function of requesting retransmission (Automatic Repeat reQuest: ARQ). RLC may also have a function for performing error correction by ARQ. The control information, which is sent from the receiving side of RLC to the transmitting side to perform ARQ and indicates the data that needs to be retransmitted, may be called a status report. The status report transmission instruction, which is sent from the transmitting side of RLC to the receiving side, may be called a poll. RLC may also have a function for detecting data duplication. RLC may also have a function for 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 divided, and an RLC header does not need to be added. The TM RLC entity is a uni-directional entity and may be configured as a transmitting TM RLC entity or a receiving TM RLC entity.In UM, the division and / or concatenation of data received from a higher layer, the addition of an RLC header, etc. are performed, but the retransmission control of data is not required. The UM RLC entity may be a unidirectional entity or a bi-directional entity. If the UM RLC entity is a unidirectional entity, the UM RLC entity may be configured as a transmitting UM RLC entity or a receiving UM RLC entity. If the UM RLC entity is a bi-directional 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 division and / or concatenation of data received from a higher layer, the addition of an RLC header, the retransmission control of data, etc. are performed. The AM RLC entity is a bi-directional 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 called a TMD PDU. Also, data provided to a lower layer in UM and / or data provided from a lower layer may be called a UMD PDU. Data provided to a lower layer in AM or data provided from a lower layer may be called 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 called RLC DATA PDUs (RLC Data PDUs). Control RLC PDUs may be called RLC CONTROL PDUs (RLC Control PDUs).

[0111] An example of the function of PDCP will be described. PDCP may be called a PDCP sublayer. PDCP may have a function of 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 sections. A protocol used for header compression / decompression of IP packets may be called ROHC (Robust Header Compression) protocol. A protocol used for header compression / decompression of Ethernet frames may be called EHC (Ethernet (registered trademark) Header Compression) protocol. PDCP may also have a function of data encryption / decryption. PDCP may also have a function of data integrity protection / integrity verification. PDCP may also have a re-ordering function. PDCP may also have a function of retransmitting PDCP SDUs. PDCP may also have a function of discarding data using a discard timer. PDCP may also have a duplication function. PDCP may also have a function to discard duplicated data. The PDCP entity is a bidirectional entity and may be composed of a transmitting PDCP entity and a receiving PDCP entity. The PDCP PDU format used in E-UTRA PDCP may differ from the PDCP PDU format used in NR PDCP. PDCP PDUs may include data PDCP PDUs and control PDCP PDUs. The data PDCP PDU may be called PDCP DATA PDU (PDCP Data PDU). The control PDCP PDU may be called PDCP CONTROL PDU (PDCP Control PDU).

[0112] An example of the function of SDAP will be described. SDAP is a service data adaptation protocol layer. SDAP may have a function of mapping a downlink QoS flow sent from 5GC to a terminal device via a base station device with a data radio bearer (DRB), and / or a function of mapping an uplink QoS flow sent from the terminal device to 5GC via a base station device with a DRB. SDAP may also have a function of storing mapping rule information. SDAP may also have a function of marking a QoS flow identifier (QoS Flow ID: QFI). Note that the SDAP PDU may include a data SDAP PDU and a control SDAP PDU. The data SDAP PDU may be called an SDAP DATA PDU (SDAP Data PDU, SDAP Data PDU). The control SDAP PDU may be called an SDAP CONTROL PDU (SDAP Control PDU, SDAP Control PDU, SDAP Control PDU). Note that one SDAP entity of the terminal device may exist 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 function of detecting and recovering radio link failures. 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, and the like. In addition, the RRC messages and parameters used in E-UTRA RRC may be different from the RRC messages and parameters used in NR RRC.

[0114] The RRC messages may be sent using the logical channel BCCH, the logical channel PCCH, the logical channel CCCH, or the logical channel DCCH, and the 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), and other RRC messages. The RRC messages sent using the PCCH may include, for example, paging messages, and other RRC messages.

[0116] The RRC message sent 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. Also, other RRC messages may be included.

[0117] The RRC message sent 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), 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 another layer.

[0121] Next, state transition of the UE 122 in LTE and NR will be described. When the UE 122 connected to the EPC or 5GC has an RRC connection established, 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 a part or all of the UE context described below. The state in which the RRC connection is established may include a state in which the UE 122 can transmit and / or receive unicast data. When the RRC connection is suspended, the UE 122 may be in an RRC_INACTIVE state. The UE 122 may be in the RRC_INACTIVE state when the UE 122 is connected to the 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] In addition, when UE 122 is connected to EPC, it does not have RRC_INACTIVE state, but E-UTRAN may initiate suspension of RRC connection. When UE 122 is connected to EPC, UE 122 may transition to RRC_IDLE state while retaining UE AS context and an identifier (resumeIdentity) used for resume when RRC connection is suspended. An upper layer (e.g., NAS layer) of the RRC layer of UE 122 may initiate restoration of the suspended RRC connection when UE 122 retains UE AS context, E-UTRAN has permitted restoration of RRC connection, and UE 122 needs to transition from RRC_IDLE state to RRC_CONNECTED state.

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

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

[0125] The UE AS context held by the UE 122 may be information including all or a part of the following: a current RRC setting, 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, and a physical cell identifier of the source PCell. Note that the UE AS context held by any 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 including all or part of the encryption key 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] The radio bearer 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. The radio bearer used for CP may be called a signaling radio bearer (SRB). The radio bearer used for UP may be called a data radio bearer (DRB). Each radio bearer may be assigned a radio bearer identity (ID). The radio bearer identifier for SRB may be called an SRB identifier (SRB Identity, or SRB ID). The radio bearer identifier for DRB may be called a DRB identifier (DRB Identity, or 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 for 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 be of 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. A DRB may be a radio bearer for user data. RRC signaling transmitted and / or received using a DRB may use the logical channel DTCH.

[0128] A radio bearer in a terminal device will be described. The radio bearer may include an RLC bearer. The RLC bearer may be composed of one or two RLC entities and logical channels. When there are two RLC entities in an RLC bearer, 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 be composed of one RLC bearer. The RLC bearer of SRB0 may be composed of a TM RLC entity and a logical channel. SRB0 may be always established in a terminal device in all states (such as an RRC idle state, an RRC connected state, and an RRC inactive state). SRB1 may be established and / or configured in the terminal device by RRC signaling received from a base station device when the terminal device transitions from an RRC idle state to an RRC connected state. SRB1 may be composed of one PDCP entity and one or more RLC bearers. The RLC bearer of SRB1 may be composed of an AM RLC entity and a logical channel. SRB2 may be established and / or configured in the terminal device by RRC signaling received from the base station device by the terminal device in the RRC connected state with AS security activated. SRB2 may be composed of one PDCP entity and one or more RLC bearers. The RLC bearer of SRB2 may be composed of an RLC entity of AM and a logical channel. The PDCP of SRB1 and SRB2 on the base station device side may be placed in the master node. SRB3 may be established and / or configured in the terminal device by RRC signaling received from the base station device by the terminal device in the RRC connected state with AS security activated when a secondary node is added in EN-DC, NGEN-DC, or NR-DC, or when the secondary node is changed. SRB3 may be a direct SRB between the terminal device and the secondary node. SRB3 may be composed of one PDCP entity and one or more RLC bearers. The RLC bearer of SRB3 may be composed of an RLC entity of AM 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 the terminal device by RRC signaling received from the base station device by the terminal device in an RRC connected state with AS security activated. The DRB may consist of one PDCP entity and one or more RLC bearers. The RLC bearer of the 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 bearer, MN terminated SCG bearer, SN terminated MCG bearer, SN terminated split bearer, and SN terminated SCG bearer, 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 addition, 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] Reference signal received power (RSRP) measured in the sidelink may be, for example, the following RSRP. In addition, 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 power contributions of resource elements that transmit multiple demodulation reference signals (DMRSs) associated with the PSBCH. The PSSCH-RSRP (PSSCH RSRP) may be defined as a linear average of power contributions of resource elements of antenna ports that transmit multiple DMRSs associated with the PSSCH, and 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 power contributions of resource elements that transmit multiple DMRSs associated with the PSCCH. Note that the DMRSs may be used to demodulate signals of the PSBCH, PSSCH, and PSCCH, for example. The terminal device may also measure the RSRP (SD-RSRP) of the discovery message using the power contributions of resource elements that transmit the DMRSs associated with the discovery message, for example.

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

[0134] There are two resource allocation modes for NR sidelink communication. Mode 1 is a mode in which the UE performs sidelink transmission using resources scheduled by the base station, and Mode 2 is a mode in which the UE automatically selects resources for sidelink transmission. In Mode 1, the UE must be RRC_CONNECTED, and 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 that have been configured before performing 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 when 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 the user that the maximum number of consecutive HARQ DTXs to a particular destination has been reached. (d) A consistency check failure is indicated by the sidelink PDCP entity for SL-SRB2 or SL-SRB3 for a particular destination.

[0136] Next, Radio Link Monitoring (RLM) in Uu will be explained.

[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 set 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 set 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, a 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 is started based on which a measurement report for a particular measurement identifier is 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 an RRC connected state, select an optimal cell and initiate a re-establishment procedure. Also, if DC is configured, a terminal device that has declared RLF may remain in an RRC connected state and notify the network of RLF.

[0140] The terminal device may be configured with a reference signal 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 the PSCell. When the PHY of the terminal device satisfies the condition for being in-sync, the PHY may notify the higher layer (RRC layer) of being in-sync. When the PHY of the terminal device satisfies the condition for being out-of-sync, the PHY may notify the higher layer (RRC, etc.) of being out-of-sync.

[0141] The radio link monitoring configuration may include information indicating a purpose of monitoring and identifier information indicating a reference signal. For example, the purpose of monitoring may include a purpose of monitoring a radio link failure, a purpose of monitoring a beam failure, or both purposes. For example, the identifier information indicating the reference signal may include information indicating an SSB-Index of an SSB of a cell. 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) set in a 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 an activated TCI state for PDCCH reception includes only one reference signal, the reference signal provided in the 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 with the QCL type set to type D is used for radio link monitoring.

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

[0144] Various embodiments of the present invention will be described based on the above description. 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. Note that, in order to avoid complicating the explanation, Fig. 8 shows only 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 control information (SCI, MAC control element, RRC signaling, etc.), discovery messages, information including user data, etc. to other terminal devices. The processor 802 may include some or all of the functions of various layers (for example, 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] FIG. 9 shows an example of an embodiment of the present invention.

[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 set for a signaling radio bearer (SRB), in step S900, the determination of the path may be determining whether the signaling radio bearer is set to a direct path. The determination that the signaling radio bearer is set to a direct path may be determining that the signaling radio bearer is not set to a non-direct path, and the determination that the signaling radio bearer is not set to a direct path may be determining that the signaling radio bearer is set to a non-direct path. If the UE 122 determines that the signaling radio bearer is set to 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 set to a direct path, in step S902, the action may be transmitting first information to a relay terminal device set to a non-direct path. Transmitting the first information to the relay terminal device set in the non-direct path may be expressed as transmitting the first information by PC5-RRC signaling using a PC5-RRC connection between the UE 122 and the relay terminal device, transmitting the first information using a sidelink signaling radio bearer 3 (SL-SRB3) between the UE 122 and the relay terminal device, etc. Also, when it is determined that the signaling radio bearer is not set in the 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 it.

[0150] In addition, when a split bearer is set for the signaling radio bearer, in step S900, the determination of the path may be to determine whether or not 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 a preferred path to a non-direct path and to transmit first information using the signaling radio bearer. If it is determined that (a) is not satisfied, the action in step S902 may be to transmit first information using the signaling radio bearer. If it is determined that (a) is satisfied and (b) is not satisfied, the action in step S902 may be to transmit 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 UE 122 is configured to measure by the base station device. (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 a UE 122 that communicates with a base station device using a direct path and a non-direct path detects a radio link failure in the non-direct path, the UE 122 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 in a non-direct path may be a sidelink radio link failure detected in a link between the UE 122 and a relay terminal device set in the non-direct path, or may be a UE 122 receiving a notification from the relay terminal device indicating that a radio link failure has been detected between the relay terminal device and a base station device. The notification may be not only a notification indicating that a radio link failure has been detected between the relay terminal device and the base station device, but also a notification indicating that the relay terminal device has failed in Uu RRC establishment or Uu RRC resume, or a notification indicating that the relay terminal device will perform reconfiguration with sync, or a notification indicating that the relay terminal device will perform cell reselection.

[0156] If a split bearer is not set for the signaling radio bearer, in step S900, the determination of the path may be a determination of whether the signaling radio bearer is set for a non-direct path. The determination that the signaling radio bearer is set for a non-direct path may be a determination that the signaling radio bearer is not set for a direct path, and the determination that the signaling radio bearer is not set for a non-direct path may be a determination that the signaling radio bearer is set for a direct path. If it is determined in step S902 that the signaling radio bearer is set for a non-direct path, the operation may be to initiate a reestablishment procedure of an RRC connection. Also, if it is determined in step S902 that the signaling radio bearer is not set for a non-direct path, the operation may be to transmit first information via the signaling radio bearer. The signaling radio bearer may be a bearer for transmitting the first information, or may be an SRB1 in addition to or instead of the SRB1.

[0157] In addition, when a split bearer is set for the signaling radio bearer, in step S900, the determination of the path may be to determine whether or not 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 a preferred path to a direct path and to transmit first information using the signaling radio bearer. If it is determined that (a) is not satisfied, the operation in step S902 may be to transmit first information using the signaling radio bearer. If it is determined that (a) is satisfied and (b) is not satisfied, the operation in step S902 may be to transmit 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 UE 122 is configured to measure by the base station device. (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] FIG. 10 shows an example of an embodiment of the present invention.

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

[0162] In step S1000, the UE 122 judges whether the signaling received from the remote terminal device is the first information, and when it is judged that the signaling received from the remote terminal device is the first information, in step S1002, the operation may be to transfer 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 UE 122 is configured to measure by the base station device. (I-3) An identifier that identifies a remote terminal and is set in a remote terminal device. (I-4) An identifier configured in UE 122 to identify a 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 L2 ID, a destination L2 ID, 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 that can identify the remote terminal device. The identifier for identifying the relay terminal may be a source L2 ID, a destination L2 ID, a C-RNTI set in the relay terminal device, a local identifier set in the L2 U2N Relay UE, or another identifier that can identify the remote terminal device.

[0166] In each embodiment, transmitting the first information using the (side link) signaling radio bearer may be rephrased as submitting the first information to a lower layer via the (side link) signaling radio bearer, or may be rephrased as another expression that exerts a similar function. In each embodiment, the UE 122 transmits the first information using the (side link) signaling radio bearer, so that the UE 122 can transmit the first information to the base station device. In addition, each embodiment may be combined with each other, and an embodiment combining each embodiment 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 a non-direct 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 addition, in the above description, expressions such as "to be notified" and "to be pointed out" may be interchangeable.

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

[0170] In addition, in the above description, expressions such as "includes," "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 addition, in the above description, expressions such as "determined to be...", "is set to...", "includes...", etc. may be interchangeable.

[0173] Furthermore, in each of the process examples or process flow examples in the above description, some or all of the steps may not be executed. Furthermore, in each of the process examples or process flow examples in the above description, the order of the steps may be different. Furthermore, in each of the process examples or process flow examples in the above description, some or all of the processing within each step may not be executed. Furthermore, in each of the process examples or process flow examples 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 "being A".

[0174] In the above explanation, "A may be replaced with B" may mean replacing A with B, as well as replacing B with A. 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". 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, when condition "A" and condition "B" are contradictory conditions, condition "B" may be expressed as the "other" condition of condition "A."

[0176] The program that runs on the device according to this embodiment may be a program that controls a Central Processing Unit (CPU) or the like to make a computer function so as to realize the functions of this 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 is stored in a non-volatile memory such as a flash memory or a Hard Disk Drive (HDD), and is read, modified, and written by the CPU as necessary.

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

[0178] Furthermore, the term "computer-readable recording medium" may 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, and a medium that stores a program for a certain period of time, such as a volatile memory inside a computer system that serves as a server or client in such a case. The above program may be one that realizes part of the above-mentioned functions, or may be one that can realize the above-mentioned functions in combination with a program already recorded in the computer system.

[0179] Also, each functional block or feature of the device used in the above-mentioned embodiment may be implemented or executed by an electric circuit, i.e., typically an integrated circuit or a plurality of integrated circuits. The electric circuit designed to execute 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. Also, when an integrated circuit technology that replaces the current integrated circuits appears due to the progress of semiconductor technology, it is possible to use an integrated circuit according to that technology.

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

[0181] Although this embodiment has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes within the scope of the gist of this embodiment are also included. In addition, this embodiment can be modified in various ways within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of this embodiment. In addition, configurations in which elements described in the above embodiment are replaced with elements that have 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 310SDAP 400 Discovery 500 PHY 502 MAC 504 RLC 506 PDCP 508 RRC 510SDAP 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, comprising a processing unit, and a transmission unit, wherein the direct path is a path through which the terminal device communicates with the base station device via the Uu interface, the indirect path is a path through which the terminal device communicates with the base station device via a relay terminal device, based on receiving, from the relay terminal device, a notification indicating that the processing unit has detected a radio link failure between the base station device and the relay terminal device, the transmission unit transmits, via a signaling radio bearer, information indicating the failure of the indirect path to the base station device, including an identifier for identifying the relay terminal device in the information, a terminal device.

2. A method for a terminal device that communicates with a base station device using a direct path and an indirect path, wherein the direct path is a path through which the terminal device communicates with the base station device via the Uu interface, the indirect path is a path through which the terminal device communicates with the base station device via a relay terminal device, based on receiving, from the relay terminal device, a notification indicating that a radio link failure has been detected between the base station device and the relay terminal device, information indicating the failure of the indirect path is transmitted to the base station device via a signaling radio bearer, including an identifier for identifying the relay terminal device in the information, a 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, wherein the direct path is a path through which the terminal device communicates with the base station device via the Uu interface, the indirect path is a path through which the terminal device communicates with the base station device via a relay terminal device, based on receiving, from the relay terminal device, a notification indicating that a radio link failure has been detected between the base station device and the relay terminal device, the integrated circuit transmits, via a signaling radio bearer, information indicating the failure of the indirect path to the base station device, exhibiting a function of including an identifier for identifying the relay terminal device in the information, an integrated circuit.

Images