Terminal device, method, and integrated circuit

Abstract

To provide a terminal device, a base station device, a communication method, and an integrated circuit that efficiently perform communication control of a technique (UE-to-UE relay) in which another terminal device is added between terminal devices and supports communication between the terminal devices.SOLUTION: In a communication system, a terminal device 122 capable of sidelink communication includes a processing unit, a receiving unit that receives a discovery message for UE-to-UE relay from a first terminal device, and a transmitting unit. The processing unit determines information to be provided to a second terminal device based on 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.SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

[0002] The 3G Partnership Project, a standardization project for cellular mobile communication systems, In the 3rd Generation Partnership Project (3GPP), Technical studies and standardization of cellular mobile communication systems, including services, are currently underway.

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

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

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

[0006] 3GPP is considering a technology called sidelink, which allows terminal devices to communicate directly with each other without going through the core network, as an extension technology of NR. In addition, research has begun on a technology (UE-to-UE relay) that allows other terminal devices to be added between terminal devices and supports communication between terminal devices.

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

[0008] In order to achieve the above object, one aspect of the present invention provides the following means: That is, one aspect of the present invention provides a terminal device capable of sidelink communication, comprising: a processing unit; a receiving unit that receives a discovery message for UE-to-UE Relay from a device, and a transmitting unit, and a processing unit that receives the discovery message from the first terminal device The transmitter determines information to be provided to the second terminal device based on the reference signal received power (RSRP), and the transmitter transmits a discovery message including the information to the second terminal device. Send a message to Barry.

[0009] Another aspect of the present invention is a method for a terminal device capable of sidelink communication, comprising: receiving a discovery message for UE-to-UE Relay from the first terminal device; and determining information to be provided to a second terminal device based on Reference Signal Received Power (RSRP) of the discovery message received from the first terminal device. and transmitting a discovery message including the information to the second terminal device. The method includes the step of:

[0010] Another aspect of the present invention is an integrated circuit implemented in a terminal device capable of sidelink communication, the integrated circuit having a function of receiving a discovery message for UE-to-UE Relay from a first terminal device. and a reference signal reception power of the discovery message received from the first terminal device. a function of determining information to be provided to a second terminal device based on Reference Signal Received Power (RSRP); and a function of transmitting a discovery message including the information to the second terminal device. Includes the ability to send.

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

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

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

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

[0015] In this embodiment, the names of the nodes and entities and the processes performed by the nodes and entities when the radio access technologies are NR and E-UTRA will be described, but this embodiment may be applied to other radio access technologies. The names of the nodes and entities in this embodiment may be different names.

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

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

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

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

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

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

[0022] Sidelink is a technology that allows direct communication between terminal devices. Reception occurs inside NG-RAN coverage and outside 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 Source Layer-2 ID and Destination Layer-2 ID. The source layer 2 identifier and the destination layer 2 identifier may be referred to as source L2ID and destination L2ID, respectively. The three transmission modes are "Unicast transmission" , "Groupcast transmission," and "Broadcast transmission."

[0024] Unicast transmission supports (1) one PC5-RRC connection between a pair of UEs; It is characterized by (2) sending and receiving control information and user traffic between UEs on the sidelink, (3) supporting sidelink HARQ feedback, (4) transmit power control on the sidelink, (5) supporting RLC AM, and (6) detecting radio link failures for PC5-RRC connections.

[0025] Groupcast transmission is also performed between UEs belonging to a sidelink group. (1) Support for sidelink HARQ feedback. do.

[0026] In addition, broadcast transmission is performed for (1) sending and receiving user traffic between UEs on the sidelink. It is characterized by faith.

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

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

[0029] Figure 3(A) is a diagram of the control plane protocol stack for SBCCH configured on the PC5 interface. As shown in Figure 3(A), the control plane protocol stack for SBCCH The network may be configured from a PHY (Physical layer) 200, which is a wireless 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. 3B is a diagram of a protocol stack of a user plane (UP) for the STCH configured on the PC5 interface. As shown in FIG. 3B, the control plane protocol stack for the STCH 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, a PDCP (Packet Data Convergence Protocol) 206, which is a packet data convergence protocol layer, and an SDAP (Service Data Adaptation Protocol) 310, which is a service data adaptation protocol layer.

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

[0031] In this embodiment, the terms PHY (PHY layer), MAC (MAC layer), RLC (RLC layer), PDCP (PDCP layer), SDAP (SDAP layer), RRC (RRC layer), and PC5-S (PC5-S layer) may be used. In this case, PHY (PHY layer), MAC (MAC layer), RLC (RLC layer), PDCP (PDCP layer), SDAP (SDAP layer), RRC (RRC layer), and PC5-S (PC5-S layer) may respectively refer to the PHY (PHY layer), MAC (MAC layer), RLC (RLC layer), PDCP (PDCP layer), SDAP (SDAP layer), RRC (RRC layer), and PC5-S (PC5-S layer) of the NR sidelink protocol. Note that when sidelink communication is performed using E-UTRA technology, the SDAP layer may not be required.

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

[0033] Describes the entities in the AS layer of E-UTRA and / or NR. An entity having some or all of the layer functionality may be referred to as a PHY entity. An entity having some or all of the MAC layer functionality may be referred to as a MAC entity. An entity having some or all of the RLC layer functionality may be referred to as an RLC entity. An entity having some or all of the PDCP layer functionality may be referred to as a PDCP entity. An entity having some or all of the SDAP layer functionality may be referred to as an SDAP entity. An entity having some or all of the RRC layer functionality 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 to lower layers by MAC, RLC, PDCP, and SDAP, and / or MAC, RLC The data provided to MAC, RLC, PDCP, and SDAP from lower layers may be called MAC PDU (Protocol Data Unit), RLC PDU, PDCP PDU, and SDAP PDU, respectively. Also, the data provided to MAC, RLC, PDCP, and SDAP from higher layers and / or data provided from MAC, RLC, PDCP, and SDAP to higher layers may be called RLC PDU (Protocol Data Unit), PDCP PDU (PDCP PDU), and SDAP PDU (SDAP PDU). These data are called MAC SDU (Service Data Unit), RLC SDU, PDCP SDU, and SDAP SDU, respectively. A segmented RLC SDU may be referred to as an RLC SDU segment.

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

[0036] Furthermore, terminal devices also exchange (transmit and receive) signals at higher layers on the PC5 interface. Terminal devices may also transmit and receive RRC messages (also referred to as RRC signaling) at a Radio Resource Control (RRC) layer. Terminal devices may also transmit and receive RRC messages at a Medium Access Control (MAC) layer. In this case, MAC Control Element (MAC CE) may be transmitted and received. Here, RRC messages and / or MAC control elements are 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, PHY In layer processing, the upper layer refers to the upper layer from the perspective of the PHY layer, and may refer to one or more of the MAC layer, RRC layer, RLC layer, PDCP layer, PC5-S layer, Discovery layer, etc. For example, MAC In the layer processing, the upper layer may refer to one or more of the RRC layer, the RLC layer, the PDCP layer, the PC5-S layer, the Discovery layer, etc.

[0037] Hereinafter, the meaning of "A is given (provided) by an upper layer" or "A is given (provided) by an upper layer" may mean that an upper layer (mainly an RRC layer, a MAC layer, etc.) of a terminal device receives A from a base station device or another terminal device, and the received A is given (provided) to a physical layer of the terminal device from the upper layer of the terminal device. For example, in a terminal device, "being provided with an upper layer parameter" may mean receiving an upper layer signal from a base station device or another terminal device, and providing an upper layer parameter included in the received upper layer signal from the upper layer of the terminal device to the physical layer of the terminal device. Setting an upper layer parameter in a terminal device may mean that the upper layer parameter is given (provided) to the terminal device. For example, setting an upper layer parameter in a terminal device may mean that the terminal device receives an upper layer signal from a base station device or another terminal device, and setting the received upper layer parameter in the upper layer. However, setting an upper layer parameter in a terminal device may also include setting a default parameter that is given in advance to an upper layer of the terminal device. When describing 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" is sometimes used. This may mean submitting a message to the PDCP layer. In this context, "submitting a message to a lower layer" may mean submitting the message to a PDCP entity corresponding to each SRB, since the RRC message is transmitted using an SRB (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 PHY function will be explained. The PHY of a terminal device can communicate with the PHY of other terminal devices. Sends and receives data transmitted via the sidelink (SL) physical channel The PHY may have a function to transmit data to the MAC via a transport channel. The PHY may be connected to a higher MAC via a transport channel. The PHY may transmit data to the MAC via the transport channel. The PHY may also receive data from the MAC via the transport channel. The PHY may use a Radio Network Temporary Identifier (RNTI) to identify various control information.

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

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

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

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

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

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

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

[0046] The MAC sublayer also performs radio resource selection on the PC5 interface to select the radio resources for sidelink transmission, and performs sidelink communication on the PC5 interface. Additional services and functions may be provided, such as packet filtering, 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] SBCCH (Sidelink Broadcast Control Channel) transmits sidelink system information in one The SBCCH may be a sidelink logical channel for broadcasting from a terminal device to one or more terminal devices. The SBCCH may be mapped to the SL-BCH, which is a sidelink transport channel. It may be tagged.

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

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

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

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

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

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

[0055] An example of the SDAP function is explained below. SDAP is a service data adaptation protocol layer (SDAP). In the sidelink, SDAP is a data adaption protocol layer (SDAP). The SDAP may have a function to map sidelink QoS flows sent from one end device to another end device with sidelink data radio bearers (DRBs). The SDAP may also have a function to store mapping rule information. The SDAP may also have a function to mark QoS flow identifiers (QFIs). SDAP PDUs may include data SDAP PDUs and control SDAP PDUs. The data SDAP PDU may be called SDAP DATA PDU (SDAP Data PDU). The control SDAP PDU may be called SDAP CONTROL PDU (SDAP Control PDU). In the sidelink, there may be one SDAP entity in the end device for each destination associated with unicast transmission, groupcast transmission, or broadcast transmission. Reflective QoS is not supported on the PC5 interface.

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

[0057] A terminal device capable of sidelink communication may perform discovery. Discovery may be performed using Model A or Model B. Figure 4 shows the protocols used in discovery. The protocol stack for Model A is described below. Mode A uses 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 outline of the procedures for Model A and Model B in ProSe Direct Discovery.

[0058] In Model A, a UE that transmits an announcement message may be called an announcing UE, and a UE that monitors the announcement message may be called a monitoring UE. The announce message may include information such as the discovery message type, ProSe Application Code or ProSe Restricted Code, and security protection element, and may additionally include metadata information. The announce message is sent using a destination Layer-2 ID (D2ID) and a source Layer-2 ID (S2ID), and the monitoring UE determines the destination L2ID to receive the announce message. Note that the destination L2ID may be the Layer-2 identifier of the destination UE, and the source L2ID may be the Layer-2 identifier of the source UE.

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

[0060] Discovery may include types other than ProSe Direct Discovery, which discovers other UEs for direct communication with them, such as Group Member Discovery, which discovers one or more UEs for intragroup communication using a sidelink, and 5G ProSe UE-to-Network Relay Discovery, which discovers candidate relay UEs for connecting to a network via a relay UE. Note that the above-described discovery is an example of discovery provided by an application called ProSe, but other than the above-described types, different types of discovery may exist depending on the application or service performing sidelink communication. Furthermore, the information included in the discovery protocol message may differ depending on the type of discovery, and additional messages may be sent to transmit additional information.

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

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

[0063] This section explains UE-to-UE relay in sidelink. UE-to-UE relay is a method in which a source UE communicates with a destination UE through a relay UE. The term "UE-to-UE relay" may be referred to as "U2U relay."

[0064] The reference signal received power (RSRP) measured in the sidelink may be, for example, the following RSRP: Furthermore, the following RSRP may be referred to as SL-RSRP. (a) PSBCH RSRP (b) PSSCH RSRP (c) PSCCH RSRP

[0065] PSBCH-RSRP (PSBCH RSRP) is a set of multiple demodulation reference signals (DRSs) associated with the PSBCH. The power distribution of resource elements that transmit the DMRS (Division Multiplexing Reference Signal) is The PSSCH-RSRP (PSSCH RSRP) may be defined as the linear average of the power contributions of the resource elements of the antenna ports transmitting the 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 the linear average of the power contributions of the resource elements of the antenna ports transmitting the multiple DMRSs associated with the PSSCH. It may be defined as the linear average of the power contributions of resource elements carrying multiple associated DMRSs, e.g., for demodulating PSBCH, PSSCH, and PSCCH signals. The terminal device may also measure the RSRP (SD-RSRP) of the discovery message using, for example, the power contribution of the resource element that transmits the DMRS associated with the discovery message.

[0066] In addition to the SL-RSRP, the UE 122 may measure the following quantities in the sidelink measurements: (a) Sidelink received signal strength indicator (SL RSSI) (b) Sidelink channel occupancy ratio (SL CR) (c) Sidelink channel busy ratio(SL CBR)

[0067] There are two resource allocation modes for NR sidelink communication, Therefore, the mode in which the UE performs sidelink transmission using scheduled resources is called Mode 1, and the mode in which the UE automatically selects resources for sidelink transmission is called Mode 2. 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. Therefore, the UE automatically selects resources available for sidelink transmission from one or more resource pools configured before the sidelink transmission.

[0068] Based on the above description, various embodiments of the present invention will be described. Note that the above-described processes may be applied to processes that are omitted in the following description.

[0069] 5 is a block diagram showing the configuration of a terminal device (UE 122) in this embodiment. In order to avoid a complicated explanation, FIG. 5 shows only the main components closely related to this embodiment. Show only.

[0070] 5 includes a receiver 500 that receives control information (SCI, MAC control element, RRC signaling, etc.), discovery messages, information including user data, etc. from other terminal devices, a processor 502 that performs processing according to parameters included in the received control information, etc., and a transmitter 504 that transmits the control information (SCI, MAC control element, RRC signaling, etc.), discovery messages, information including user data, etc. to other terminal devices. In addition, the processor 502 may include some or all of the functions of various layers (e.g., a physical layer, a MAC layer, an RLC layer, a PDCP layer, an SDAP layer, an RRC layer, a PC5-S layer, a discovery layer, and an application layer). That is, the processing unit 502 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.

[0071] An example of an embodiment of the present invention will be described with reference to FIG.

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

[0073] In step S602, the information transmitted from UE 122 to the second terminal device based on the discovery message may be, for example, RSRP (SD-RSRP) measured in the received discovery message, or may be, for example, an offset value determined based on RSRP (SD-RSRP) measured in the received discovery message. Additionally or alternatively, in step S602, the information transmitted from UE 122 to the second terminal device based on the discovery message may be, for example, RSRP (SL-RSRP) measured in sidelink communication when UE 122 is performing sidelink communication with the first terminal device, or may be, for example, an offset value determined based on RSRP (SL-RSRP) measured in sidelink communication when UE 122 is performing sidelink communication with the first terminal device. Additionally or alternatively, in step S602, the information transmitted by the UE 122 to the second terminal device based on the discovery message may be, for example, a path loss measured in the received discovery message, or an offset value determined based on the path loss measured in the received discovery message. Note that even when sidelink communication with the first terminal device is being performed, SD-RSRP, path loss, or the like may be used instead of SL-RSRP.

[0074] In step S604, the UE 122 provides the information to the second terminal device by, for example, transmitting a discovery message including the information to the second terminal device. The information may be provided from the AS layer to a layer higher than the AS layer, and the layer higher than the AS layer may include the information in a discovery message and transmit it to the second terminal device. or may be configured as a MAC Control Element (MAC CE) for the second terminal device. may be transmitted as

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

[0076] Instead of passing the information to the second terminal device, the UE 122 determines the discovery message to be transmitted to the second terminal device according to the SD-RSRP, SL-RSRP, path loss, or offset value. For example, when using SD-RSRP, if the SD-RSRP is in a first range, a first resource pool may be used to transmit discovery messages, and if the SD-RSRP is in a second range, a second resource pool may be used to transmit discovery messages. Furthermore, when the UE 122 transmits a discovery message using a first resource pool and the second terminal device receives a discovery message in a resource pool corresponding to the first resource pool, the second terminal device may determine that the SD-RSRP is within the first range. Furthermore, the second terminal device may determine that the UE 122 is a relay UE in U2U relay. The RSRP of the received discovery message may be evaluated based on the determination to determine whether to select the discovery message.

[0077] FIG. 7 shows another embodiment of the present invention.

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

[0079] In step S702, the determination may be, for example, determining whether the RSRP (SD-RSRP) of the received discovery message is better than a threshold. Additionally or alternatively, in step S702, the determination may be, for example, determining whether the path loss of the received discovery message is better than a threshold. Additionally or alternatively, in step S702, the determination may be, for example, determining whether the RSRP (SL-RSRP) in the sidelink communication is better than a threshold when sidelink communication is being performed with the first terminal device. Note that the SD-RSRP being better than a threshold may mean that the SD-RSRP is equal to or greater than a threshold, and the SD-RSRP being worse than a threshold may mean that the SD-RSRP is less than a threshold. Furthermore, the path loss being better than a threshold may mean that the path loss is equal to or less than a threshold, and the path loss being worse than a threshold may mean that the path loss is greater than a threshold. Furthermore, the SL-RSRP being better than a threshold may mean that the SL-RSRP is equal to or greater than the threshold, and the SL-RSRP being worse than the threshold may mean that the SL-RSRP is less than the threshold. Note that the determination of whether the SL-RSRP is equal to or greater than the threshold may be replaced with a determination of whether the SL-RSRP is greater than the threshold or less than the threshold.

[0080] In step S702, if it is determined that the SD-RSRP, the path loss, or the SL-RSRP is better than a threshold, in step S704, for example, the operation is, for example, to the second terminal device. In response to the received discovery message, the action may be to transmit a discovery message based on the received discovery message. Additionally or alternatively, the action may be to forward the received discovery message to an upper layer (Discovery). In addition, if it is determined in step S702 that the SD-RSRP, the path loss, or the SL-RSRP is worse than a threshold, the operation in step S704 is, for example, to the second terminal device. In response to the received discovery message, the action may be to not send a discovery message. Additionally or alternatively, the action may be to not forward the received discovery message to an upper layer (Discovery). good.

[0081] It should be noted that the UE 122 determines whether the SD-RSRP, the path loss, or the SL-RSRP is good. The threshold for the UE 122 to receive the data may be preset by the network or may be set by the network. The first terminal device may determine a threshold value and transmit the determined threshold value by signaling of a higher layer (such as an RRC or application layer), or may transmit the determined threshold value together with a discovery message by being included in a MAC CE, etc. When the determined threshold value is transmitted in the application layer, the threshold value may be transmitted as information included in a discovery message.

[0082] The discovery message in each embodiment is used for U2U relay. It may be a discovery message. For example, a discovery message sent from the first terminal device. The discovery message may include information about the first terminal device and information about the second terminal device. Also, for example, a discovery message transmitted from UE 122 may include information about the first terminal device, information about UE 122, and information about the second terminal device. The information about UE 122 and each terminal device may be an identifier that identifies each terminal. Additionally or alternatively, other information may be included. The discovery message may also include information about the type of discovery message.

[0083] In each embodiment, the first terminal device, the second terminal device, and the other terminal devices are terminal devices capable of sidelink communication, similar to the UE 122, and include a receiving unit, a processing unit, and The terminal device may be configured to include a transmitting unit.

[0084] Relay UE selection in UE-to-UE relay using the operations shown in Non-Patent Documents 1, 5, and 6 However, in each embodiment, the UE can evaluate the relay path including not only the link quality between itself and the relay UE but also the link quality between the relay UE and other UEs, and select a more suitable relay UE.

[0085] In the above description, expressions such as "notified" and "indicated" may be interchangeable.

[0086] In the above description, expressions such as "link," "associate," and "link" may be interchangeable.

[0087] In addition, in the above description, expressions such as "included," "included," and "was included" may be used interchangeably.

[0088] In the above description, "the above-mentioned" may be replaced with "the above-mentioned."

[0089] In the above explanation, "confirmed to be...", "set to be...", "includes..." Expressions such as these may be interchangeable.

[0090] Furthermore, in each example of processing or each example of processing flow in the above description, some or all of the steps may not be executed. Furthermore, in each example of processing or each example of processing flow in the above description, the order of the steps may be different. Furthermore, in each example of processing or each example of processing flow in the above description, some or all of the processing within each step may not be executed. Furthermore, in each example of processing or each example of processing flow in the above description, the order of the processing within each step may be different. Furthermore, in the above description, "doing B based on A being true" may be rephrased as "doing B." In other words, "doing B" may be executed independently of "A being true."

[0091] In the above explanation, "A may be replaced with B" may mean replacing A with B, as well as replacing B with A. Also, in the above explanation, when it is written that "C may be D" and "C may be E", it may also mean that "D may be E". Also, in the above explanation, when it is written that "F may be G" and "G may be H", it may also mean that "F may be H".

[0092] In the above explanation, if the conditions "A" and "B" are contradictory conditions, the condition "B" may be expressed as the "other" condition of the condition "A."

[0093] A program running on an apparatus according to the present embodiment may be a program that controls a central processing unit (CPU) or the like to cause a computer to function so as to realize the functions of the present embodiment. The program or information handled by the program is temporarily loaded into a volatile memory such as a random access memory (RAM) during processing, or stored in a nonvolatile memory such as a flash memory or a hard disk drive (HDD), and is read, modified, or written by the CPU as necessary.

[0094] Note that a part of the device in the above-described embodiment may be realized by a computer. In this case, a program for realizing this control function may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read and executed by a computer system. The "computer system" here refers to a computer system built into the device, including hardware such as an operating system and peripheral devices. Furthermore, the "computer-readable recording medium" may be any of a semiconductor recording medium, an optical recording medium, a magnetic recording medium, etc.

[0095] Furthermore, the term "computer-readable recording medium" may also include a medium that dynamically stores a program for a short period of time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, or a medium that stores a program for a certain period of time, such as a volatile memory within a computer system that serves as a server or client in such cases. The program may also be one that realizes part of the above-mentioned functions, or one that can realize the above-mentioned functions in combination with a program already stored in the computer system.

[0096] Furthermore, each functional block or feature of the device used in the above-described embodiments may be implemented or performed by an electric circuit, typically an integrated circuit or a plurality of integrated circuits. The electric circuit designed to perform the functions described herein may be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable logic circuit (FPLC), a microprocessor (MCU), a microcomputer (CPU ... The general-purpose processor may include 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. Additionally, if advances in semiconductor technology result in the emergence of integrated circuit technologies that can replace current integrated circuits, integrated circuits based on those technologies may also be used.

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

[0098] Although this embodiment has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment and includes design modifications within the scope of the gist of this embodiment. Furthermore, this embodiment can be modified in various ways within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of this embodiment. Furthermore, configurations in which elements described in the above embodiment are substituted with elements that achieve the same effect are also included. [Explanation of symbols]

[0099] 100 ng-eNB 102 gNB 110, 112, 114 Interface 122UE 200 PHY 202 MAC 204 RLC 206 PDCP 208 RRC 210 PC5-S 310 SDAP 400 Discovery 500 Receiver 502 Processing section 504 Transmission Unit

Claims

1. A terminal device capable of sidelink communication, a processing unit; Receiving a discovery message for UE-to-UE Relay from the first terminal device Department and a transmitter unit, The processing unit receives a reference signal of the discovery message from the first terminal device. determining information to be provided to the second terminal device based on received power (Reference Signal Received Power: RSRP); The transmission unit transmits a discovery message including the information to the second terminal device. Send, Terminal device.

2. A method for a terminal device capable of sidelink communication, comprising: receiving a discovery message for UE-to-UE Relay from a first terminal device; determining information to be provided to a second terminal device based on Reference Signal Received Power (RSRP) of the discovery message received from the first terminal device; The transmission unit transmits a discovery message including the information to the second terminal device. and transmitting the method.

3. An integrated circuit implemented in a terminal device capable of sidelink communication, A function of receiving a discovery message for UE-to-UE Relay from a first terminal device. and, a function of determining information to be provided to a second terminal device based on Reference Signal Received Power (RSRP) of the discovery message received from the first terminal device; The transmission unit transmits a discovery message including the information to the second terminal device. It demonstrates the functionality and reliability of Integrated circuit.

Images