Terminal device, method, and integrated circuit

Abstract

A terminal device capable of performing sidelink communication is provided with: a processing unit; a reception unit that receives the discovery message from the first terminal device; and a transmission unit in which a processing unit determines information to be provided to a second terminal device on the basis of the reference signal received power (RSRP) of the discovery message received from the first terminal device, and the transmission unit transmits the discovery message including the information to the second terminal device.

Description

Technical Field

[0001] The present invention relates to a terminal device, a method and an integrated circuit. This application claims priority to Japanese Patent Application No. 2022-122522 filed in Japan on August 1, 2022, the contents of which are incorporated herein by reference. Background Art

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

[0003] For example, 3GPP has started technical research and standardization of E-UTRA (Evolved Universal Terrestrial Radio Access) as a radio access technology (Radio Access Technology: RAT) for cellular mobile communication systems for 3.9 and 4 generations. Currently, 3GPP is also conducting technical research and standardization of extended technologies for E-UTRA. It should be noted that E-UTRA is also called Long Term Evolution (LTE: registered trademark, Long Term Evolution), and sometimes the extended technology is also called LTE-Advanced (LTE-A) and LTE-Advanced Pro (LTE-A Pro).

[0004] In addition, 3GPP has started technical research 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 also conducting technical research and standardization of NR extension technologies. Prior art literature 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 38.321v17.0.0, "NR; Medium Access Control (MAC) protocol specification" pp17-104 Non-patent document 3: 3GPP TS 38.213v17.2.0, “NR; Physical layer procedures for control” pp14-20 Non-patent document 4: 3GPP TS 38.215v17.1.0, “NR; Physical layer measurements” pp16-18 Non-patent document 5: 3GPP TS23.304v17.1.0, "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 that the invention aims to solve

[0006] In 3GPP, as an extension technology of NR, the sidelink technology that allows terminal devices to communicate directly with each other without going through the core network is studied, and research has begun on the technology of adding other terminal devices between terminal devices to support communication between terminal devices (UE-to-UE relay: UE to UE relay).

[0007] An aspect of the present invention has been made in view of the above-mentioned situation, and one of its objects is to provide a terminal device, a base station device, a communication method, and an integrated circuit that can efficiently perform communication control. Technical Solution

[0008] In order to achieve the above-mentioned purpose, one scheme of the present invention adopts the following scheme. That is, one scheme of the present invention is a terminal device capable of sidelink communication, the terminal device comprising: a processing unit; a receiving unit, a discovery message for UE-to-UE relay is received by a first terminal device; and a sending unit, the processing unit determines information to be provided to a second terminal device based on a reference signal received power (RSRP) of the discovery message received by the first terminal device, and the sending unit sends a discovery message including the information to the second terminal device.

[0009] In addition, an embodiment of the present invention is a method for a terminal device capable of sidelink communication, the method comprising the following steps: receiving, by a first terminal device, a discovery message for UE-to-UE relay; determining information to be provided to a second terminal device based on a reference signal received power (Reference Signal Received Power: RSRP) of the discovery message received by the first terminal device; and sending a discovery message including the information to the second terminal device.

[0010] In addition, one embodiment of the present invention is an integrated circuit installed in a terminal device capable of sidelink communication, the integrated circuit including the following functions: receiving a discovery message for UE-to-UE relay by a first terminal device; determining information to be provided to a second terminal device based on a reference signal received power (Reference Signal Received Power: RSRP) of the discovery message received by the first terminal device; and sending a discovery message including the information to the second terminal device.

[0011] It should be noted that these inclusive or specific solutions can be implemented through systems, devices, methods, integrated circuits, computer programs or recording media, or through any combination of systems, devices, methods, integrated circuits, computer programs and recording media. Beneficial Effects

[0012] According to one aspect of the present invention, a terminal device, a method, and an integrated circuit can implement efficient communication control processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the communication system according to this embodiment. Figure 2 This is a diagram showing an example of the protocol configuration of the side link according to the present embodiment. Figure 3This is a diagram showing an example of the protocol configuration of the side link according to the present embodiment. Figure 4 This is a diagram showing an example of the protocol configuration of the side link according to the present embodiment. Figure 5 This is a block diagram showing the configuration of a terminal device according to this embodiment. Figure 6 This is an example of the discovery-related processing of this embodiment. Figure 7 This is an example of the discovery-related processing of this embodiment. DETAILED DESCRIPTION

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

[0015] It should be noted that in this embodiment, the names of each node and entity and the processing in each node and entity are described when the radio access technology is NR and E-UTRA, but this embodiment can also be applied to other radio access technologies. The names of each node and entity in this embodiment can also be other names.

[0016] Figure 1 is a schematic diagram of the communication system of this embodiment. Figure 1 The functions of each node, wireless access technology, core network, interface, etc. described above are some functions closely related to this embodiment, and may also have other functions.

[0017] E-UTRA can be a radio access technology. In addition, E-UTRA can also be the air interface between UE122 and ng-eNB100. The air interface 112 between UE122 and ng-eNB100 can be called Uu interface. ng-eNB (ng E-UTRAN Node B: ng E-UTRAN node B) 102 can be a base station device of E-UTRA. ng-eNB100 can have the E-UTRA protocol described later. The E-UTRA protocol can also be composed of the E-UTRA user plane (User Plane: UP) protocol described later and the E-UTRA control plane (Control Plane: CP) protocol described later. ng-eNB100 can terminate the E-UTRA user plane protocol and the E-UTRA control plane protocol for UE122. The radio access network composed of eNB can also be called E-UTRAN.

[0018] NR can be a wireless access technology. In addition, NR can also be the air interface between UE122 and gNB102. The air interface 112 between UE122 and gNB102 can be called Uu interface. gNB (g Node B: g node B) 102 can be a base station device of NR. gNB102 can have the NR protocol described later. The NR protocol can be composed of the NR user plane (User Plane: UP) protocol described later and the NR control plane (Control Plane: CP) protocol described later. gNB102 can terminate the NR user plane protocol and the NR control plane protocol for UE122.

[0019] It should be noted that the interface 110 between the ng-eNB 100 and the gNB 102 may be referred to as an Xn interface. In addition, the ng-eNB and the gNB may be connected to the 5GC via an interface referred to as 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] The state in which the base station device can be connected only via the Uu interface may be referred to as Inside NG-RAN Coverage or In-Coverage (IC). In addition, the state in which the base station device cannot be connected only via the Uu interface may be referred to as Outside NG-RAN Coverage or Out-of-Coverage (OOC). The air interface 114 between UE122 and UE122 may be referred to as a PC5 interface. Communication between UE122 via the PC5 interface may be referred to as sidelink (SL) communication. In addition, a terminal device capable of sidelink communication may be referred to as a terminal device capable of sidelink communication.

[0021] It should be noted that in the following description, ng-eNB100 and / or gNB102 are also referred to as base station devices only, and UE122 is also referred to as terminal devices or UEs only. In addition, the PC5 interface is also referred to as PC5 only, and the Uu interface is also referred to as Uu only.

[0022] Sidelink refers to a technology for direct communication between terminal devices. Sidelink transmission and reception on PC5 are performed inside and outside the NG-RAN coverage area.

[0023] NR SL communication has three transmission modes, and SL communication is performed in any transmission mode through a pair of a second source layer identifier (Source Layer-2ID) and a second destination layer identifier (Destination Layer-2 ID). The second source layer identifier and the second destination layer identifier may also be referred to as source L2ID and destination L2ID, respectively. The three transmission modes are "Unicast transmission", "Groupcast transmission" and "Broadcast transmission".

[0024] The characteristics of unicast transmission are: (1) supporting one PC5-RRC connection between paired UEs, (2) sending and receiving control information and user services between UEs in the side link, (3) supporting side link HARQ (Hybrid Automatic Repeat reQuest) feedback, (4) transmitting power control in the side link, (5) supporting RLCAM, and (6) detecting wireless link failure for PC5-RRC connection.

[0025] In addition, the characteristics of multicast transmission are: (1) transmission and reception of user traffic between UEs belonging to a sidelink group, and (2) support of sidelink HARQ feedback.

[0026] In addition, broadcast transmission is characterized by: (1) user traffic is transmitted and received between UEs on the side link.

[0027] Figure 2 and Figure 3 This is a diagram of an example of a protocol architecture in NR sidelink communication according to this embodiment. Figure 2 and / or Figure 3 The functions of each protocol described above are some functions closely related to this embodiment, and may have other functions. It should be noted that in this embodiment, the sidelink (SL) may be a link between terminal devices.

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

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

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

[0031] It should be noted that 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) are sometimes 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) can 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. It should be noted that when the E-UTRA technology is used for sidelink communication, the SDAP layer may not be present.

[0032] In addition, in the present embodiment, hereinafter, when distinguishing between the protocol of E-UTRA and the protocol of NR, PHY, MAC, RLC, PDCP, and RRC are sometimes 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. In addition, PHY, MAC, RLC, PDCP, and RRC are sometimes described as E-UTRA PHY or LTE PHY, E-UTRA MAC or LTEMAC, E-UTRA RLC or LTE RLC, E-UTRA PDCP or LTE PDCP, and E-UTRA RRC or LTE RRC, respectively. In addition, when distinguishing between the protocol of E-UTRA and the protocol of NR, PHY, MAC, RLC, PDCP, and RRC are sometimes referred to as PHY for NR, MAC for NR, RLC for NR, RLC for NR, and RRC for NR, respectively. In addition, PHY, MAC, RLC, PDCP and RRC are sometimes recorded as NR PHY, NR MAC, NR RLC, NR PDCP, NR RRC, etc.

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

[0034] It should be noted that the data provided from MAC, RLC, PDCP, SDAP to the lower layer and / or the data provided from the lower layer to MAC, RLC, PDCP, SDAP may be referred to as MAC PDU (Protocol Data Unit), RLC PDU, PDCP PDU, SDAP PDU, respectively. In addition, the data provided from the upper layer to MAC, RLC, PDCP, SDAP and / or the data provided from MAC, RLC, PDCP, SDAP to the upper layer may be referred to as MAC SDU (Service Data Unit), RLC SDU, PDCP SDU, SDAP SDU, respectively. In addition, the segmented RLC SDU may be referred to as an RLC SDU segment.

[0035] Here, the base station device and the terminal device exchange (transmit and receive) signals at the upper layer (upper layer: higher layer) on the Uu interface. The higher layer may also be referred to as the upper layer, and may also be interchangeable with each other. For example, the base station device and the terminal device may transmit and receive RRC messages (also referred to as RRCmessage, RRC signalling: RRC signaling) in the radio resource control (RRC: Radio Resource Control) layer. In addition, the base station device and the terminal device may also transmit and receive MAC control elements (MAC Control Element: MAC CE) in the MAC (Medium Access Control) layer. In addition, the RRC layer of the terminal device obtains system information broadcast from the base station device. Here, the RRC message, system information and / or MAC control element are also referred to as upper layer signals (upper layer signals: higher layer signaling) or upper layer parameters (upper layer parameters: higher layer parameter). The parameters included in the upper layer signal received by the terminal device may be referred to as upper layer parameters, respectively. For example, in the processing of the PHY layer, the upper layer means the upper layer observed from the PHY layer, and therefore, may mean one or more of the MAC layer, the RRC layer, the RLC layer, the PDCP layer, the NAS (Non Access Stratum) layer, etc. For example, the upper layer in the processing of the MAC layer may refer to one or more of the RRC layer, the RLC layer, the PDCP layer, the NAS layer, etc.

[0036] In addition, terminal devices also exchange (transmit and receive) signals at the upper layer (upper layer: higher layer) on the PC5 interface. Terminal devices can also send and receive RRC messages (also called RRC message, RRC signalling) at the radio resource control (RRC: Radio Resource Control) layer. In addition, terminal devices can also send and receive MAC control elements (MAC Control Element: MAC CE) at the MAC (Medium Access Control) layer. Here, RRC messages and / or MAC control elements are also referred to as upper layer signals (upper layer signals: higher layer signaling) or upper layer parameters (upper layer parameters: higher layer parameters). The parameters included in the upper layer signals received by the terminal device can also be referred to as upper layer parameters. For example, in the processing of the PHY layer, the upper layer means the upper layer observed from the PHY layer, and therefore, it can mean one or more of the MAC layer, RRC layer, RLC layer, PDCP layer, PC5-S layer, discovery layer, etc. For example, the upper layer in the processing of the MAC layer may refer to one or more of an RRC layer, an RLC layer, a PDCP layer, a PC5-S layer, a discovery layer, and the like.

[0037] In the following, "A is given (provided) by the upper layer" and "A is given (provided) by the upper layer" may mean that the upper layer of the terminal device (mainly the RRC layer, MAC layer, etc.) receives A from the base station device or other terminal devices, and gives (provides) the received A from the upper layer of the terminal device to the physical layer of the terminal device. For example, in the terminal device, "providing upper layer parameters" may mean receiving an upper layer signal from the base station device or other terminal devices, and providing the upper layer parameters included in the received upper layer signal from the upper layer of the terminal device to the physical layer of the terminal device. Setting upper layer parameters for the terminal device may mean giving (providing) upper layer parameters to the terminal device. For example, setting upper layer parameters for the terminal device may mean that the terminal device receives an upper layer signal from the base station device or other terminal devices, and sets the received upper layer parameters in the upper layer. Among them, setting upper layer parameters for the terminal device may include setting default parameters for the upper layer given to the terminal device in advance. When explaining the sending of an RRC message from a terminal device to a base station device or other terminal device, the expression that the RRC entity of the terminal device submits a message to the lower layer (lower layer) is sometimes used. In the terminal device, "proposing a message to the lower layer" from the RRC entity may also mean proposing a message to the PDCP layer. Since SRBs (SRB0, SRB1, SRB2, SRB3, etc.) are used to send RRC messages, "proposing (submitting) a message to the lower layer" from the RRC layer in the terminal device may also mean proposing an RRC message to the PDCP entity corresponding to each SRB. When the RRC entity of the terminal device receives a notification (indication) from the lower layer, the lower layer may also mean one or more of the PHY layer, MAC layer, RLC layer, PDCP layer, etc.

[0038] An example of the function of PHY is described. The PHY of a terminal device may have the function of transmitting and receiving data transmitted via a sidelink (SL) physical channel with the PHY of other terminal devices. PHY can be connected to the upper MAC via a transport channel. PHY can deliver data to MAC via a transport channel. In addition, PHY can provide data from MAC via a transport channel. RNTI (Radio Network Temporary Identifier) ​​can be used in PHY to identify various control information.

[0039] Here, the physical channels are described. The physical channels used for wireless communication between a terminal device and other terminal devices 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] PSBCH may be used to broadcast system information required by terminal devices.

[0042] PSCCH can be used to indicate resources and other transmission parameters related to PSSCH.

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

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

[0045] An example of the function of MAC is described. MAC can also be called a MAC sublayer (sublayer). MAC can have the function of mapping multiple logical channels (logical channels: Logical Channel) to corresponding transmission channels. Logical channels can be identified by logical channel identifiers (Logical Channel Identity or Logical Channel ID). MAC can be connected to the upper RLC through logical channels (Logical Channel). Logical channels can be divided into control channels for transmitting control information and service channels for transmitting user information according to the type of information transmitted. MAC can have the function of multiplexing MAC SDUs belonging to one or more different logical channels and providing them to PHY. In addition, MAC can have the function of demultiplexing MAC PDUs provided from PHY and providing them to the upper layer via the logical channels to which each MAC SDU belongs. In addition, MAC can have the function of performing error correction through HARQ (Hybrid Automatic Repeat reQuest). In addition, MAC can have the function of reporting scheduling information. MAC can have the function of using dynamic scheduling to perform priority processing between terminal devices. In addition, MAC may have a function of performing priority processing between logical channels within a terminal device. MAC may have a function of performing priority processing of overlapping resources within a terminal device. E-UTRA MAC may have a function of identifying Multimedia Broadcast Multicast Services (MBMS). In addition, NR MAC may have a function of identifying Multicast / Broadcast Services (MBS). MAC may have a function of selecting a transmission format. MAC may have a function of performing discontinuous reception (DRX) and / or discontinuous transmission (DTX), a function of performing a random access (RA) process, a power headroom report (PHR) function that notifies information on the transmittable power, a buffer status report (BSR) function that notifies information on the amount of data in the transmit buffer, and the like. NR MAC may have a bandwidth adaptation (BA) function.In addition, the MAC PDU format used in the E-UTRA MAC and the MAC PDU format used in the NR MAC may be different. In addition, the MAC PDU may include a MAC control element (MAC Control Element: MAC CE) which is an element for controlling in the MAC.

[0046] In addition, the MAC sublayer can 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 communications, priority processing between uplink and sidelink, and reporting of sidelink channel state information (Sidelink Channel State Information: Sidelink CSI).

[0047] The following describes the mapping of sidelink (SL) logical channels and sidelink logical channels and transport channels used in E-UTRA and / or NR.

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

[0049] SCCH (Sidelink Control Channel) can be a sidelink logical channel for transmitting control information such as PC5-RRC messages and PC5-S messages from one terminal device to one or more terminal devices. In addition, SCCH can be mapped to SL-SCH as a sidelink transmission channel.

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

[0051] An example of the function of RLC is described. RLC may also be referred to as an RLC sublayer (sublayer). E-UTRA RLC may have a function of segmenting and / or concatenating data provided from the upper layer PDCP and providing it to the lower layer. E-UTRA RLC may have a function of reassembling and reordering data provided from the lower layer and providing it to the upper layer. NR RLC may have a function of attaching a sequence number independent of the sequence number attached in the PDCP to the data provided from the upper layer PDCP. In addition, NR RLC may have a function of segmenting data provided from the PDCP and providing it to the lower layer. In addition, NR RLC may have a function of reassembling data provided from the lower layer and providing it to the upper layer. In addition, RLC may have a data retransmission function and / or a retransmission request function (Automatic Repeat reQuest: ARQ). In addition, RLC may have a function of performing error correction through ARQ. The control information indicating the data that needs to be retransmitted and sent from the receiving side to the sending side of the RLC for ARQ can be called a status report. In addition, the status report sending indication sent from the sending side of the RLC to the receiving side can be called a poll. In addition, the RLC can have a function of detecting data duplication. In addition, the RLC can have a function of discarding data. There can be three modes in the RLC, namely, a transparent mode (TM), an unacknowledged mode (UM), and an acknowledged mode (AM). Under TM, the data received from the upper layer may not be segmented, and the RLC header may not be attached. The TM RLC entity may be a uni-directional entity, set as a transmitting TM RLC entity or a receiving TM RLC entity. Under UM, the data received from the upper layer may be segmented and / or concatenated, the RLC header may be attached, etc., but the retransmission control of the data may not be performed. The UM RLC entity may be a uni-directional entity or a bi-directional entity. When 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. When the UM RLC entity is a bidirectional entity, the UM RLC entity may be configured as a UM RLC entity consisting of a transmitting side and a receiving side.Under AM, segmentation and / or concatenation of data received from the upper layer, attachment of RLC headers, data retransmission control, etc. can be performed. The AM RLC entity can be a bidirectional entity, set as an AM RLC consisting of a transmitting side and a receiving side. It should be noted that the data provided to the lower layer and / or the data provided from the lower layer under TM can be referred to as TMDPDU. In addition, the data provided to the lower layer and / or the data provided from the lower layer under UM can be referred to as UMD PDU. In addition, the data provided to the lower layer or the data provided from the lower layer under AM can be referred to as AMD PDU. The RLC PDU format used in E-UTRA RLC and the RLC PDU format used in NR RLC can be different. In addition, the RLC PDU can include RLC PDU for data and RLC PDU for control. The RLC PDU for data can be referred to as RLC DATA PDU (RLC Data PDU, RLC data PDU). In addition, the control RLC PDU can be called RLC CONTROL PDU (RLC Control PDU, RLC control PDU, RLC control PDU).

[0052] It should be noted that, on the sidelink, TM can be used for SBCCH, only UM is used in multicast transmission and broadcast transmission, and UM and AM can be used in unicast transmission. In addition, on the sidelink, UM in multicast transmission and broadcast transmission only supports unidirectional transmission.

[0053] An example of the function of PDCP is described. PDCP can be called a PDCP sublayer (sublayer). PDCP can have a function of maintaining a sequence number. In addition, PDCP can also have a header compression / decompression function for efficiently transmitting user data such as IP packets (IPPackets) and Ethernet frames in wireless intervals. The protocol for header compression / decompression of IP packets can be called the ROHC (Robust Header Compression) protocol. In addition, the protocol for Ethernet frame header compression / decompression can be called the EHC (Ethernet (registered trademark) Header Compression: Ethernet Header Compression) protocol. In addition, PDCP can also have a data encryption / decoding function. In addition, PDCP can also have a data integrity protection / integrity verification function. In addition, PDCP can also have a reordering function. In addition, PDCP can also have a PDCP SDU retransmission function. In addition, PDCP can also have a data discarding function using a discard timer. In addition, PDCP can also have a multiplexing function. In addition, PDCP can also have a function of discarding duplicated received data. The PDCP entity can be a bidirectional entity, consisting of a transmitting PDCP entity and a receiving PDCP entity. In addition, the PDCP PDU format used in E-UTRA PDCP and the PDCP PDU format used in NR PDCP may be different. In addition, the PDCP PDU may include a PDCP PDU for data and a PDCP PDU for control. The PDCP PDU for data may be referred to as a PDCP DATA PDU (PDCPData PDU, PDCP data PDU). In addition, the PDCP PDU for control may be referred to as a PDCP CONTROL PDU (PDCPControl PDU, PDCP control PDU, PDCP control PDU).

[0054] It should be noted that on the sidelink, there are the following restrictions on the functions and services of PDCP. (1) Out-of-order transmission can be supported only in unicast transmission. (2) Duplication on the PC5 interface is not supported.

[0055] An example of the function of SDAP is described. SDAP is a service data adaptation protocol layer. On the side link, SDAP may have the function of establishing a correspondence (mapping: mapping) between the QoS flow of the side link sent from the terminal device to other terminal devices and the side link data radio bearer (DRB). In addition, SDAP may have the function of storing mapping rule information. In addition, SDAP may have the function of marking the QoS flow identifier (QoS Flow ID: QFI). It should be noted that there may be SDAP PDU for data and SDAP PDU for control in the SDAP PDU. The SDAP PDU for data may be referred to as SDAP DATA PDU (SDAP Data PDU, SDAP data PDU). In addition, the SDAP PDU for control may be referred to as SDAP CONTROL PDU (SDAP Control PDU, SDAP control PDU, SDAP control PDU). It should be noted that on the side link, the SDAP entity of the terminal device may exist for each destination for any of unicast transmission, multicast transmission, and broadcast transmission associated with the destination (destination). Additionally, reflective QoS is not supported on the PC5 interface.

[0056] An example of the functions of RRC is described. RRC can support services and functions such as the transmission of PC5-RRC messages between peer UEs, the maintenance and release of PC5-RRC connections between two UEs, and the detection of sidelink radio link failure for PC5-RRC connections on the PC5 interface. The 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. In addition, there is a one-to-one correspondence between the PC5-RRC connection and the PC5 unicast link. In addition, the UE has multiple PC5-RRC connections for one or more UEs, for different pairs with different source L2IDs and destination L2IDs. Separate PC5-RRC processes and messages can be used for the UE to transmit UE capabilities and sidelink configurations to peer UEs. In addition, the peer UEs of both parties can use a separate two-way process to exchange their own UE capabilities and sidelink configurations with each other. In the case of no interest in sidelink transmission, when a sidelink radio link failure is detected for the PC5-RRC connection and the second layer link release procedure is completed, the UE releases the PC5-RRC connection.

[0057] Terminal devices capable of sidelink communication can be discovered. Model A and Model B can exist in the discovery. Figure 4 The protocol stack used in discovery is recorded in . It can be that model A uses a single discovery protocol message and model B uses two discovery protocol messages. The single discovery protocol message in model A can be an announcement message, and the discovery protocol message in model B can be an invitation message and a response message. The following shows an overview of the process of model A and model B in ProSe Direct Discovery.

[0058] In model A, the UE that sends the announcement message may also be called the announcing UE, and the UE that monitors the announcement message may also be called the monitoring UE. The announcement message may include information such as the type of discovery message, ProSe application code (ProSe Application Code) or ProSe restriction code (ProSe Restricted Code), security protection element (security protection element), and may also include metadata information. The announcement message is sent using the destination L2ID (Destination Layer-2 ID) and the source L2ID (Source Layer-2 ID), and the monitoring UE determines the destination L2ID for receiving the announcement message. It should be noted that the destination L2ID can be the second layer (Layer-2) identifier of the destination UE, and the source L2ID can be the second layer identifier of the source UE.

[0059] In model B, the UE that sends the invitation message can be called a discoverer UE, and the UE that receives the invitation message and / or sends a response message to the discoverer UE can be called a discoveree UE. The invitation message may include information such as the type of discovery message, ProSe Query Code, and security protection element. The invitation message is sent using the destination L2ID and the source L2ID, and the discoverer UE determines the destination L2ID for receiving the invitation message. In addition, the discoverer UE that responds to the invitation message sends a response message. The response message may include information such as the type of discovery message, ProSe response code, and security protection element, and may also include metadata information in addition. The response message is sent using the source L2ID, and the destination L2ID is set to the source L2ID of the received invitation message.

[0060] There may also be types other than ProSe direct discovery in discovery for discovering other UEs in order to communicate directly with other UEs, and there may also be group member discovery (Group member Discovery) for discovering one or more UEs for communication within a group using a side link, and 5G ProSe UE-to-Network Relay Discovery (5G ProSe UE-to-Network Relay Discovery) for discovering candidate relay UEs in order to connect to the network via a relay UE. It should be noted that the above discovery is an example of discovery provided by an application called ProSe, but in addition to the above types, there are also different types of discovery depending on the application or service performing sidelink communication. In addition, the information included in the discovery protocol message may also vary depending on the type of discovery, and additional messages may be sent to send additional information.

[0061] Figure 4 FIG. 1 is a diagram showing an example of a protocol structure including a discovery protocol according to the present embodiment. Figure 4As shown, the protocol stack of the discovery plane including the discovery protocol can be composed of PHY (Physical layer) 200 as a radio physical layer (Radio physical layer), MAC (Medium Access Control) 202 as a medium access control layer (Medium access control layer), RLC (Radio Link Control) 204 as a radio link control layer (Radio link control layer), PDCP (Packet Data Convergence Protocol) 206 as a packet data convergence protocol layer (Packet data convergence protocol layer) and discovery 400 as a discovery protocol layer (Discovery protocol layer). Discovery 400 can be a protocol for processing processes related to discovery. In addition, the interface between UEs performing discovery can be called PC5-D.

[0062] Multiple resource pools for sending discovery messages can be set, and one or more resource pools can be set specifically for discovery. The UE can also use the resource pool dedicated to discovery as the resource pool for sending discovery messages when the resource pool dedicated to discovery is set, and use the resource pool for sidelink communication as the resource pool for sending discovery messages when the resource pool dedicated to discovery is not set. It should be noted that multiple resource pools for sidelink communication and resource pools dedicated to discovery can also be set at the same time. Each resource pool can be set by UE-specific signaling or can be set in advance.

[0063] UE-to-UE relay on the sidelink is explained. UE-to-UE relay refers to a technology that communicates with a source UE (Source UE) and a destination UE (Destination UE) via a sidelink communication with a relay UE (Relay UE). The source UE, destination UE, and relay UE may also be referred to by different names. In addition, the phrase UE-to-UE relay may also be referred to as U2U relay (U2U relay).

[0064] The reference signal received power (RSRP) measured on the sidelink may refer to, 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

[0065] PSBCH-RSRP (PSBCH RSRP) can be defined as the linear average of the power contributions of resource elements that transmit multiple demodulation reference signals (DMRS) associated with PSBCH. In addition, PSSCH-RSRP (PSSCH RSRP) can be defined as the linear average of the power contributions of resource elements of antenna ports that transmit multiple DMRS associated with PSSCH. When there are multiple antenna ports, the RSRP value of each antenna port can be summed up. PSCCH-RSRP (PSCCH RSRP) can be defined as the linear average of the power contributions of resource elements that transmit multiple DMRS associated with PSCCH. It should be noted that DMRS can be used to demodulate PSBCH, PSSCH and PSCCH signals, for example. In addition, the terminal device can measure the RSRP (SD-RSRP) of the discovery message using the power contribution of resource elements that transmit DMRS associated with the discovery message.

[0066] Furthermore, in the sidelink measurements, 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)

[0067] There are two resource allocation modes in the sidelink communication of NR. The mode in which the UE uses the resources scheduled by the base station to perform sidelink transmission is called mode 1, and the mode in which the UE automatically selects resources to perform sidelink transmission is called mode 2. In mode 1, the UE needs to be in RRC_CONNECTED. In mode 2, the UE can perform sidelink transmission regardless of the RRC state or the inside or outside of the NG-RAN. It should be noted that in mode 2, the UE automatically selects resources that can perform sidelink transmission from one or more resource pools set before performing sidelink transmission.

[0068] Based on the above description, various embodiments of the present invention are described. It should be noted that the above-described processes can be applied to the processes omitted in the following description.

[0069] Figure 5 1 is a block diagram showing the configuration of the terminal device (UE122) according to the present embodiment. Figure 5 Only the main components closely related to this embodiment are shown.

[0070] Figure 5 The UE 122 shown has: a receiving unit 500, which receives control information (SCI, MAC control element, RRC signaling, etc.), discovery messages, and information including user data, etc. from other terminal devices; a processing unit 502, which processes according to parameters included in the received control information, etc.; and a sending unit 504, which sends control information (SCI, MAC control element, RRC signaling, etc.), discovery messages, and information including user data, etc. to other terminal devices. In addition, the processing unit 502 may include some or all of the functions of various layers (for example, physical layer, MAC layer, RLC layer, PDCP layer, SDAP layer, RRC layer, PC5-S layer, discovery layer, and application layer). That is, the processing unit 502 may include part 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.

[0071] use Figure 6 An example of an embodiment of one aspect of the present invention is shown.

[0072] When the UE 122 capable of sidelink communication receives a discovery message from the first terminal device in step S600 , it determines information to be sent to the second terminal device based on the received discovery message in step S602 , and provides the information to the second terminal device in step S604 .

[0073] The information sent by UE122 to the second terminal device based on the discovery message in step S602 may, for example, refer to the RSRP (SD-RSRP) measured in the received discovery message, or may, for example, refer to an offset value determined based on the RSRP (SD-RSRP) measured in the received discovery message. In addition or instead, the information sent by UE122 to the second terminal device based on the discovery message in step S602 may, for example, refer to the RSRP (SL-RSRP) measured in the sidelink communication in the case of sidelink communication with the first terminal device, or may, for example, refer to an offset value determined based on the RSRP (SL-RSRP) measured in the sidelink communication in the case of sidelink communication with the first terminal device. In addition or instead, the information sent by UE122 to the second terminal device based on the discovery message in step S602 may, for example, refer to the path loss measured in the received discovery message, or may, for example, refer to an offset value determined based on the path loss measured in the received discovery message. It should be noted that even in the case of sidelink communication with the first terminal device, SD-RSRP or path loss may be used instead of SL-RSRP.

[0074] In step S604, UE122 providing the information to the second terminal device may, for example, refer to sending a discovery message including the information to the second terminal device. The information is provided from the AS layer to a layer higher than the AS layer, and the layer higher than the AS layer may send the information to the second terminal device by including the information in the discovery message, or may send the information to the second terminal device as a MAC control element (MAC CE: MAC Control Element).

[0075] In addition, when the second terminal device receives a discovery message including the information from one or more terminal devices, the second terminal device may use the information and the RSRP (SD-RSRP) of the received discovery message to determine which terminal device to select as the relay terminal (Relay UE) in the U2U relay to the first terminal device, or the second terminal device may use the RSRP (SL-RSRP) of the sidelink communication or the path loss of the received discovery message when performing sidelink communication with the terminal device that sends the discovery message to determine which terminal device to select as the relay terminal (Relay UE) in the U2U relay to the first terminal device. For example, when the second terminal device is provided with an offset value of the SD-RSRP as the information, the second terminal device may evaluate the RSRP (SD-RSRP) of the received discovery message by taking into account the provided offset value.

[0076] It should be noted that, instead of delivering the information to the second terminal device, UE122 may select a resource pool for sending a discovery message to the second terminal device based on SD-RSRP, SL-RSRP, path loss or offset value. For example, it may be that, in the case of using SD-RSRP, when the SD-RSRP is in the first range, the first resource pool is used to send the discovery message, and when the SD-RSRP is in the second range, the second resource pool is used to send the discovery message. In addition, when UE122 uses the first resource pool to send a discovery message, and the second terminal device receives a discovery message in the resource pool corresponding to the first resource pool, it can be determined that the SD-RSRP is in the first range. In addition, in order to determine whether to select UE122 as the relay UE in the U2U relay, the second terminal device can evaluate the RSRP of the received discovery message based on the judgment.

[0077] In addition, use Figure 7 An example of another embodiment of one aspect of the present invention is shown.

[0078] When the UE 122 capable of sidelink communication receives a discovery message from the first terminal device in step S700 , it makes a judgment based on the received discovery message in step S702 , and takes action based on the judgment in step S704 .

[0079] In step S702, the judgment may, for example, refer to judging whether the RSRP (SD-RSRP) of the received discovery message is better than a threshold. Additionally or alternatively, in step S702, the judgment may, for example, refer to judging whether the path loss of the received discovery message is better than a threshold. Additionally or alternatively, in step S702, the judgment may, for example, refer to judging whether the RSRP (SL-RSRP) in the sidelink communication is better than a threshold in the case of sidelink communication with the first terminal device. It should be noted that the SD-RSRP being better than the threshold may mean that the SD-RSRP is above the threshold, and the SD-RSRP being worse than the threshold may mean that the SD-RSRP is less than the threshold. In addition, the path loss being better than the threshold may mean that the path loss is below the threshold, and the path loss being worse than the threshold may mean that the path loss is greater than the threshold. In addition, the SL-RSRP being better than the threshold may mean that the SL-RSRP is above the threshold, and the SL-RSRP being worse than the threshold may mean that the SL-RSRP is less than the threshold. It should be noted that the determination of whether the value is above the threshold or below the threshold may be replaced by the determination of whether the value is above the threshold or below the threshold.

[0080] In a case where it is determined in step S702 that the SD-RSRP, the path loss or the SL-RSRP is better than a threshold value, in step S704, for example, the action may refer to sending a discovery message based on the received discovery message to the second terminal device. In addition or instead of this, for example, the action may refer to transmitting the received discovery message to an upper layer (discovery). In addition, in a case where it is determined in step S702 that the SD-RSRP, the path loss or the SL-RSRP is worse than a threshold value, in step S704, the action may refer to not sending a discovery message based on the received discovery message to the second terminal device. In addition or instead of this, for example, the action may refer to not transmitting the received discovery message to an upper layer (discovery).

[0081] It should be noted that the threshold for UE122 to determine whether the SD-RSRP, the path loss or the SL-RSRP is good can be set by the network in advance for UE122, or the threshold can be determined by the first terminal device and sent through signaling of the upper layer (RRC, application layer, etc.), or can also be sent together with the discovery message by including it in MAC CE, etc. In the case where the determined threshold is sent by the application layer, the threshold can be sent as information included in the discovery message.

[0082] It should be noted that the discovery message in each embodiment may be a discovery message for U2U relay. For example, the discovery message sent from the first terminal device may include information related to the first terminal device and information related to the second terminal device. In addition, for example, the discovery message sent from UE122 may include information related to the first terminal device, information related to UE122, and information related to the second terminal device. The information related to UE122 and each terminal device may be an identifier for identifying each terminal, and may include other information in addition to or instead of this. In addition, the discovery message may include information related to the type of discovery message.

[0083] It should be noted that in each embodiment, the first terminal device, the second terminal device and the other multiple terminal devices can be terminal devices capable of sidelink communication like UE122, that is, they can be terminal devices having a structure including a receiving unit, a processing unit and a sending unit.

[0084] When the relay UE selection in UE-to-UE relay is performed using the actions shown in non-patent documents 1, 5, and 6, the UE can only evaluate the quality of the link with the directly connected UE. However, according to each embodiment, the UE can evaluate the relay path including the quality of the link between the relay UE and other UEs in addition to the quality of the link between itself and the relay UE, and select a more suitable relay UE.

[0085] Furthermore, in the above description, expressions such as "notify", "accept the blame", etc. can be used interchangeably.

[0086] Furthermore, in the above description, expressions such as “associated with”, “establishing correspondence”, and “establishing association” can be interchangeable.

[0087] Furthermore, in the above description, expressions such as “include”, “including”, and “comprising” can be replaced with each other.

[0088] Furthermore, in the above description, "the" may be replaced by "the above-mentioned".

[0089] Furthermore, in the above description, expressions such as "determined to be ...", "set to be ...", and "including ..." can be replaced with each other.

[0090] In addition, in the examples of each processing or the examples of the processes of each processing in the above description, some or all of the steps may not be executed. In addition, in the examples of each processing or the examples of the processes of each processing in the above description, the order of the steps may be different. In addition, in the examples of each processing or the examples of the processes of each processing in the above description, some or all of the processing in each step may not be executed. In addition, in the examples of each processing or the examples of the processes of each processing in the above description, the order of the processing in each step may be different. In addition, in the above description, "based on A, perform B" may also be renamed as "perform B". That is, "perform B" may also be performed independently of "is A".

[0091] It should be noted that in the above description, "A may be renamed as B" includes not only the meaning of renaming A as B, but also the meaning of renaming B as A. In addition, in the above description, when "C may be D" and "C may be E" are recorded, the case of "D may be E" may also be included. In addition, in the above description, when "F may be G" and "G may be H" are recorded, the case of "F may be H" may also be included.

[0092] Furthermore, in the above description, when the condition “A” and the condition “B” are opposite conditions, the condition “B” can be expressed as an “other” condition of the condition “A”.

[0093] The program that operates through the device of this embodiment can be a program that controls the central processing unit (CPU) and the like to make the computer function to realize the functions of this embodiment. The program or the information processed by the program is temporarily read into a volatile memory such as a random access memory (RAM) or stored in a non-volatile memory such as a flash memory or a hard disk drive (HDD) during processing, and is read, modified, or written by the CPU as needed.

[0094] It should be noted that a part of the device in the above-mentioned embodiment can also be implemented by a computer. In this case, the program for implementing the control function can be recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed. The "computer system" mentioned here refers to a computer system built into the device, and includes a computer system of hardware such as an operating system and peripherals. In addition, the "computer-readable recording medium" can be any one of a semiconductor recording medium, an optical recording medium, a magnetic recording medium, etc.

[0095] Furthermore, "computer-readable recording medium" may also include: a recording medium that stores a program dynamically for a short period of time, such as a communication line when the program is transmitted via a network such as the Internet or a communication line such as a telephone line; and a recording medium that stores a program for a fixed period of time, such as a volatile memory inside a computer system that serves as a server or client in this case. In addition, the above-mentioned program may be a program for realizing a part of the functions described, or may be a program that can realize the functions described by combining with a program already recorded in a computer system.

[0096] In addition, each functional block or each feature of the device used in the above-mentioned embodiments can be implemented or executed by a circuit, that is, typically by an integrated circuit or multiple integrated circuits. Circuits designed in a manner to perform the functions described in this specification may include: a general-purpose processor, a digital signal processor (DSP), an integrated circuit for a specific purpose (ASIC), a field programmable gate array (FPGA) or other programmable logic elements, discrete gates or transistor logic, discrete hardware parts, or a combination thereof. The general-purpose processor may be a microprocessor, and the processor may also be replaced by an existing processor, controller, microcontroller or state machine. The general-purpose processor or the circuits described may be composed of digital circuits or analog circuits. In addition, in the case of an integrated circuit technology that replaces existing integrated circuits as semiconductor technology advances, integrated circuits based on this technology may also be used.

[0097] It should be noted that the present embodiment is not limited to the above-mentioned embodiment. In the embodiment, an example of a device is described, but the present embodiment is not limited thereto and can be applied to fixed or non-movable electronic devices set up indoors and outdoors, such as AV equipment, kitchen equipment, cleaning / washing equipment, air conditioning equipment, office equipment, vending machines, and other terminal devices or communication devices such as other living equipment.

[0098] The present embodiment has been described in detail with reference to the accompanying drawings, but the specific configuration is not limited to the present embodiment, and also includes design changes within the scope of the gist of the present embodiment. In addition, the present embodiment can be modified in various ways within the scope indicated by the claims, and the embodiment obtained by appropriately combining the technical solutions disclosed in different embodiments is also included in the technical scope of the present embodiment. In addition, it also includes a configuration obtained by replacing elements that have the same effect as the elements described in the above embodiments with each other. Industrial Applicability

[0099] One aspect of the present invention can be used for example in a communication system, a communication device (such as a mobile phone device, a base station device, a wireless LAN device, or a sensor device), an integrated circuit (such as a communication chip), a program, or the like. Description of Reference Numerals 100: ng-eNB; 102: gNB; 110, 112, 114: interface; 122:UE; 200: PHY; 202: MAC; 204: RLC; 206: PDCP; 208:RRC; 210: PC5-S; 310: SDAP; 400: Found; 500: receiving unit; 502: Processing department; 504: Sending unit.

Claims

1. A terminal device capable of sidelink communication, wherein: The terminal device comprises: Processing Department; a receiving unit, receiving a discovery message from the first terminal device; and Sending Department, The processing unit determines information to be provided to the second terminal device based on the reference signal received power RSRP of the discovery message received from the first terminal device, The transmitting unit transmits a discovery message including the information to the second terminal device.

2. A method of a terminal device, which is a method of a terminal device capable of sidelink communication, wherein: The method comprises the following steps: receiving a discovery message from a first end device; determining information to be provided to a second terminal device based on a reference signal received power (RSRP) of the discovery message received from the first terminal device; and The transmitting unit transmits a discovery message including the information to the second terminal device.

3. An integrated circuit installed in a terminal device capable of sidelink communication, wherein: The integrated circuit performs the following functions: receiving a discovery message from a first end device; The device further comprises: determining information to be provided to a second terminal device based on a reference signal received power RSRP of the discovery message received from the first terminal device; and a transmitting unit transmitting a discovery message including the information to the second terminal device.

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