Method and apparatus for transmitting / receiving wireless signal in wireless communication system

Abstract

In the present disclosure, a method performed by a first user equipment (UE) in a wireless communication system may comprise the steps of: receiving information on a second UE from the second UE through a second RAT connection between the first UE and the second UE; transmitting, to a base station (BS), a first RAT-based signal including information on the second UE received through the second RAT connection; and receiving configuration information for an indirect path between the first UE and the BS from the BS, in which information on the second UE received over the second RAT connection may include a UE identifier of the second UE allocated by the BS based on the first RAT.

Description

Technical Field

[0001] The present disclosure relates to a wireless communication system, and more particularly, to a method and an apparatus for transmitting / receiving a wireless signal. Background Art

[0002] Wireless communication systems have been widely deployed to provide various types of communication services, such as voice or data. Generally, a wireless communication system is a multiple access system that supports communication of multiple users by sharing available system resources (bandwidth, transmission power, etc.). Examples of multiple access systems include CDMA systems, FDMA systems, TDMA systems, OFDMA systems, SC-FDMA systems, and MC-FDMA systems.

[0003] A sidelink (SL) refers to a communication scheme in which a direct link is established between user equipment (UE) and UE and UEs directly exchange voice or data without the intervention of a base station (BS). SL is considered a solution to relieve the rapidly growing data traffic constraint of the BS.

[0004] Vehicle-to-everything (V2X) is a communication technology in which a vehicle exchanges information with another vehicle, a pedestrian, and an infrastructure through wired / wireless communication. V2X can be divided into four types: vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-network (V2N), and vehicle-to-pedestrian (V2P). V2X communication can be provided via a PC5 interface and / or a Uu interface.

[0005] As more and more communication devices require greater communication capacity, enhanced mobile broadband communication relative to existing RATs is needed. Accordingly, communication systems that consider services or UEs sensitive to reliability and latency are being discussed. A next-generation RAT that considers eMBB, MTC, and URLLC is called a new RAT or NR. In NR, V2X communication can also be supported.

[0006] Figure 1 is a diagram contrastively illustrating V2X communication based on a pre-NR-RAT and V2X communication based on NR.

[0007] For V2X communication, in a pre-NR RAT, techniques for providing a security service based on V2X messages such as basic safety messages (BSM), cooperative awareness messages (CAM), and decentralized environmental notification messages (DENM) have been mainly discussed. V2X messages may include location information, dynamic information, and attribute information. For example, a UE may transmit a CAM of a periodic message type and / or a DENM of an event trigger type to another UE.

[0008] For example, the CAM may include basic vehicle information, including dynamic state information such as direction and speed, vehicle static data such as size, external lighting state, path details, etc. For example, the UE may broadcast the CAM, and the waiting time of the CAM may be less than 100 ms. For example, when an unexpected event such as vehicle damage or an accident occurs, the UE may generate a DENM and send the DENM to another UE. For example, all vehicles within the transmission range of the UE may receive the CAM and / or the DENM. In this case, the priority of the DENM may be higher than that of the CAM.

[0009] Regarding V2X communication, various V2X scenarios have been proposed in NR. For example, the V2X scenarios include vehicle platooning, advanced driving, extended sensors, and remote driving.

[0010] For example, vehicles can be dynamically grouped and made to travel together based on vehicle platooning. For example, in order to perform platooning operations based on vehicle platooning, the vehicles in the group may receive periodic data from the leading vehicle. For example, the vehicles in the group may widen or narrow their gaps based on the periodic data.

[0011] For example, based on advanced driving, the vehicle can be semi-automatic or fully automatic. For example, each vehicle can adjust its trajectory or maneuver based on data obtained from nearby vehicles and / or nearby logical entities. For example, each vehicle can also share its driving intention with nearby vehicles.

[0012] For example, based on extended sensors, raw or processed data or real-time video data obtained through local sensors can be exchanged between vehicles, logical entities, pedestrian terminals, and / or V2X application servers. Therefore, the vehicle can perceive a high-level environment relative to the environment that can be sensed by the vehicle's sensors.

[0013] For example, based on remote driving, a remote driver or a V2X application can operate or control a remote vehicle on behalf of a person who is unable to drive or is in a dangerous environment. For example, when the path can be predicted as in public transportation, cloud-based driving can be used to operate or control the remote vehicle. For example, access to a cloud-based backend service platform can also be used for remote driving.

[0014] In NR-based V2X communication, solutions for specifying service requirements for various V2X scenarios including vehicle platooning, advanced driving, extended sensors, and remote driving have been discussed. Summary of the Invention

[0015] Technical Problem

[0016] An object of the present disclosure is to provide a method and an apparatus for accurately and efficiently performing a wireless signal transmission / reception process.

[0017] Those skilled in the art will appreciate that the objectives that can be achieved using the present disclosure are not limited to those specifically described above, and the above and other objectives that can be achieved by the present disclosure will be more clearly understood from the following detailed description.

[0018] Technical solution

[0019] In one aspect of the present disclosure, a method performed by a first user equipment (UE) in a wireless communication system supporting one or more radio access technologies (RATs) including a first RAT may include the following steps: receiving information about the second UE from the second UE via a second RAT connection between the first UE and the second UE; sending a first-RAT-based signal including the information about the second UE received via the second RAT connection to a base station (BS); and receiving configuration information for an indirect path via the second UE between the first UE and the BS. The information about the second UE received via the second RAT connection may include a UE identifier of the second UE assigned by the BS based on the first RAT.

[0020] Preferably, the UE identifier of the second UE may be a cell-radio network temporary identifier (C-RNTI) of the second UE.

[0021] Preferably, the C-RNTI of the second UE is sent to the BS to report to the BS that the second UE may be in a radio resource control (RRC) connected state based on the first RAT.

[0022] Preferably, the second UE may be a candidate for a relay UE configured for the indirect path.

[0023] Preferably, the configuration information for the indirect path may include information about the relay UE.

[0024] Preferably, the relay UE may be determined based on the first-RAT-based signal sent by the first UE.

[0025] Preferably, the first UE may be a remote UE configured with a direct path to the BS. The direct path may be configured by performing a random access procedure with the BS.

[0026] Preferably, the indirect path may include a first RAT connection between the second UE and the BS and the second RAT connection between the first UE and the second UE.

[0027] Preferably, the first RAT may be a 3rd Generation Partnership Project (3GPP) RAT, and the second RAT may be a non-3GPP RAT.

[0028] Preferably, the second RAT connection may be different from the 3GPP sidelink connection.

[0029] In another aspect of the present disclosure, a computer-readable storage medium storing instructions is provided, and when the instructions are executed by a processor, the processor is caused to execute the above method.

[0030] In another aspect of the present disclosure, a first UE configured to execute the method is provided.

[0031] In another aspect of the present disclosure, a processing device configured to control a first UE is provided, and the UE is configured to execute the method.

[0032] In another aspect of the present disclosure, a method performed by a base station (BS) in a wireless communication system supporting one or more radio access technologies (RATs) including a first RAT may include the following steps: receiving, from a first user equipment (UE), a second RAT-based signal including information about one or more UEs; determining configuration information for an indirect path between the first UE and the BS via a second UE; and sending the configuration information for the indirect path to the first UE. The information about one or more UEs may include information about a second UE having a second RAT connection with the first UE. The information about the second UE may include a UE identifier assigned to the second UE by the BS based on the first RAT.

[0033] In another aspect of the present disclosure, a BS configured to execute the method is provided.

[0034] Advantageous Effects

[0035] According to an embodiment of the present disclosure, a wireless signal transmission / reception process can be accurately and efficiently performed.

[0036] Those skilled in the art will understand that the effects that the present disclosure can achieve are not limited to the content specifically described above, and other advantages of the present disclosure will be more clearly understood from the following detailed description in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a diagram contrastively illustrating vehicle-to-everything (V2X) communication based on a legacy New Radio (NR) RAT and V2X communication based on NR.

[0038] Figure 2Illustrates the structure of an LTE system to which the applicable embodiments can be applied.

[0039] Figure 3 Illustrates the structure of an NR system to which the applicable embodiments can be applied.

[0040] Figure 4 Illustrates the structure of an NR radio frame to which the applicable embodiments can be applied.

[0041] Figure 5 Illustrates the slot structure of an NR frame to which the applicable embodiments can be applied.

[0042] Figure 6 Illustrates the radio protocol architecture for SL communication.

[0043] Figure 7 Illustrates a UE that performs V2X or SL communication.

[0044] Figure 8 Illustrates a resource unit for V2X or SL communication.

[0045] Figure 9 Illustrates the UE - to - UE coordination information MAC CE.

[0046] Figure 10 Illustrates the UE - to - UE coordination request MAC CE.

[0047] Figure 11 Illustrates (a) the user plane protocol stack and (b) the control plane protocol stack for L2 UE - to - network relay.

[0048] Figure 12 Illustrates the protocol stack for the discovery message of UE - to - network relay.

[0049] Figure 13 Illustrates the procedure for L2 U2N remote UE connection establishment.

[0050] Figure 14 Illustrates the procedure for U2N remote UE to switch to a direct Uu cell.

[0051] Figure 15 Illustrates the procedure for U2N remote UE to switch to an indirect path.

[0052] Figure 16 Illustrates an example of U2N bearer establishment for L2 U2N remote UE and L2 U2N relay UE.

[0053] Figure 17 Illustrates an example of gNB - initiated Uu addition / modification.

[0054] Figure 18Illustrates a first example of the U2N addition process based on Uu.

[0055] Figure 19 Illustrates a second example of the U2N addition process based on Uu.

[0056] Figure 20 Illustrates a third example of the U2N addition process based on Uu.

[0057] Figure 21 Illustrates a remote UE sending remote UE information to a relay UE.

[0058] Figure 22 Illustrates a method performed by a user equipment (UE) in an embodiment of the present disclosure.

[0059] Figure 23 Illustrates a method performed by a base station (BS) in an embodiment of the present disclosure.

[0060] Figure 24 Illustrates a communication system to which the present disclosure is applied.

[0061] Figure 25 Illustrates a wireless device applicable to the present disclosure.

[0062] Figure 26 Illustrates another example of a wireless device to which the present disclosure is applied.

[0063] Figure 27 Illustrates a vehicle or autonomous driving vehicle to which the present disclosure is applied. Detailed implementation

[0064] A wireless communication system is a multi-access system that supports communication of multiple users by sharing available system resources (bandwidth, transmission power, etc.). Examples of multi-access systems include CDMA systems, FDMA systems, TDMA systems, OFDMA systems, SC-FDMA systems, and MC-FDMA systems.

[0065] Details of the background, terms, abbreviations, etc. used herein can be found in the following documents.

[0066] 3GPP LTE

[0067] - 3GPP TS 36.211: Physical Channels and Modulation

[0068] - 3GPP TS 36.212: Multiplexing and Channel Coding

[0069] - 3GPP TS 36.213: Physical Layer Procedures

[0070] - 3GPP TS 36.214: Physical Layer; Measurements

[0071] - 3GPP TS 36.300: General Description

[0072] - 3GPP TS 36.304: User Equipment (UE) Procedures in Idle Mode

[0073] - 3GPP TS 36.314: Layer 2 - Measurements

[0074] - 3GPP TS 36.321: Medium Access Control (MAC) Protocol

[0075] - 3GPP TS 36.322: Radio Link Control (RLC) Protocol

[0076] - 3GPP TS 36.323: Packet Data Convergence Protocol (PDCP)

[0077] - 3GPP TS 36.331: Radio Resource Control (RRC) Protocol

[0078] 3GPP NR

[0079] - 3GPP TS 38.211: Physical Channels and Modulation

[0080] - 3GPP TS 38.212: Multiplexing and Channel Coding

[0081] - 3GPP TS 38.213: Physical Layer Procedures for Control

[0082] - 3GPP TS 38.214: Physical Layer Procedures for Data

[0083] - 3GPP TS 38.215: Physical Layer Measurements

[0084] - 3GPP TS 38.300: General Description

[0085] - 3GPP TS 38.304: User Equipment (UE) Procedures in Idle Mode and RRC Inactive State

[0086] - 3GPP TS 38.321: Medium Access Control (MAC) Protocol

[0087] - 3GPP TS 38.322: Radio Link Control (RLC) Protocol

[0088] - 3GPP TS 38.323: Packet Data Convergence Protocol (PDCP)

[0089] - 3GPP TS 38.331: Radio Resource Control (RRC) Protocol

[0090] - 3GPP TS 37.324: Service Data Adaptation Protocol (SDAP)

[0091] - 3GPP TS 37.340: Multi-Connection; Overall Description

[0092] A sidelink (SL) is a communication scenario in which a direct link is established between user equipment (UE) and UE, and the UEs directly exchange voice or data without the intervention of a base station (BS). SL is considered a solution to relieve the rapidly growing data traffic constraint on the BS.

[0093] Vehicle-to-Everything (V2X) is a communication technology in which a vehicle exchanges information with another vehicle, a pedestrian, and infrastructure via wired / wireless communication. V2X can be classified into four types: Vehicle-to-Vehicle (V2V), Vehicle-to-Infrastructure (V2I), Vehicle-to-Network (V2N), and Vehicle-to-Pedestrian (V2P). V2X communication can be provided via the PC5 interface and / or the Uu interface.

[0094] As more and more communication devices require greater communication capacity, enhanced mobile broadband communication relative to existing RATs is needed. Therefore, communication systems that take into account services or UEs sensitive to reliability and latency are being discussed. The next-generation RAT that takes into account eMBB, MTC, and URLLC is called the new RAT or NR. In NR, V2X communication can also be supported.

[0095] The techniques described herein can be used in various wireless access systems such as Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier Frequency Division Multiple Access (SC-FDMA), etc. CDMA can be implemented as radio technologies such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA can be implemented as radio technologies such as Global System for Mobile Communications (GSM) / General Packet Radio Service (GPRS) / Enhanced Data Rates for GSM Evolution (EDGE). OFDMA can be implemented as radio technologies such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Evolved UTRA (E-UTRA), etc. IEEE 802.16m is an evolution of IEEE 802.16e, providing backward compatibility with systems based on IEEE 802.16e. UTRA is part of the Universal Mobile Telecommunications System (UMTS). The 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is part of the Evolved UMTS (E-UMTS) that uses Evolved UTRA (E-UTRA). 3GPP LTE employs OFDMA for the downlink (DL) and SC-FDMA for the uplink (UL). LTE-Advanced (LTE-A) is an evolution of 3GPP LTE. 3GPP New Radio (NR) (New Radio or New Radio Access Technology) is an evolved version of 3GPP LTE / LTE-A / LTE-A pro.

[0096] The successor of LTE-A, the 5th Generation (5G) New Radio Access Technology (NR), is a new clean-state mobile communication system characterized by high performance, low latency, and high availability. 5G NR can utilize all available spectrum resources, including low-frequency bands below 1 GHz, intermediate-frequency bands between 1 GHz and 10 GHz, and high-frequency (millimeter) bands of 24 GHz or above.

[0097] Although the following description is mainly given in the context of LTE-A or 5G NR for clarity of description, the technical concepts of the embodiments of the present disclosure are not limited thereto.

[0098] Figure 2 Illustrates the structure of an LTE system according to an embodiment of the present disclosure. This can also be referred to as the Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) or the LTE / LTE-A system.

[0099] Refer to Figure 2, the E-UTRAN includes evolved Node Bs (eNBs) 20 that provide a control plane and a user plane to the UE 10. The UE 10 can be fixed or mobile and can also be referred to as a mobile station (MS), user terminal (UT), subscriber station (SS), mobile terminal (MT), or wireless device. The eNB 20 is a fixed station that communicates with the UE 10 and can also be referred to as a base station (BS), base transceiver system (BTS), or access point.

[0100] The eNBs 20 can be connected to each other via the X2 interface. The eNB 20 is connected to the evolved packet core (EPC) 39 via the S1 interface. More specifically, the eNB 20 is connected to the mobility management entity (MME) via the S1-MME interface and to the serving gateway (S-GW) via the S1-U interface.

[0101] The EPC 30 includes the MME, S-GW, and packet data network gateway (P-GW). The MME has access information or capability information about the UE, which is mainly used for the mobility management of the UE. The S-GW is a gateway with the E-UTRAN as an endpoint, and the P-GW is a gateway with the packet data network (PDN) as an endpoint.

[0102] Based on the lowest three layers of the well-known Open Systems Interconnection (OSI) reference model in a communication system, the radio protocol stack between the UE and the network can be divided into layer 1 (L1), layer 2 (L2), and layer 3 (L3). These layers are defined in pairs between the UE and the evolved UTRAN (E-UTRAN) for data transmission via the Uu interface. The physical (PHY) layer at L1 provides an information transfer service on physical channels. The radio resource control (RRC) layer at L3 is used to control the radio resources between the UE and the network. For this purpose, the RRC layer exchanges RRC messages between the UE and the eNB.

[0103] Figure 3 Illustrates the structure of an NR system according to an embodiment of the present disclosure.

[0104] Refer to Figure 3 , the next-generation radio access network (NG-RAN) can include next-generation Node Bs (gNBs) and / or eNBs that provide user plane and control plane protocol termination to the UE. In Figure 4 , for example, the NG-RAN is shown as including only gNBs. The gNBs and eNBs are connected to each other via the Xn interface. The gNBs and eNBs are connected to the 5G core network (5GC) via the NG interface. More specifically, the gNBs and eNBs are connected to the access and mobility management function (AMF) via the NG-C interface and to the user plane function (UPF) via the NG-U interface.

[0105] Figure 4 Illustrates the radio frame structure in NR to which embodiments of the present disclosure are applicable.

[0106] Referring to Figure 4 , the radio frame can be used for UL transmission and DL transmission in NR. The length of the radio frame is 10 ms and can be defined by two 5-ms half-frames. A HF can include five 1-ms subframes. A subframe can be divided into one or more time slots, and the number of time slots in the SF can be determined according to the subcarrier spacing (SCS). Each time slot can include 12 or 14 OFDM(A) symbols according to the cyclic prefix (CP).

[0107] In the case of normal CP (NCP), each time slot can include 14 symbols, while in the case of extended CP (ECP), each time slot can include 12 symbols. Herein, a symbol can be an OFDM symbol (or CP-OFDM symbol) or an SC-FDMA symbol (or DFT-s-OFDM symbol).

[0108] Table 1 below lists the number of symbols N per time slot, the number of time slots N per frame slot symb , and the number of time slots N per subframe frame,u slot in the case of NCP according to the SCS configuration μ. subframe,u slot .

[0109] [Table 1]

[0110] <![CDATA[SCS(15*2 u )]]> <![CDATA[N slot symb > <![CDATA[N frame,u slot > <![CDATA[N subframe,u slot > 15 kHz (u = 0) 14 10 1 30 kHz (u = 1) 14 20 2 60 kHz (u = 2) 14 40 4 120 kHz (u = 3) 14 80 8 240 kHz (u = 4) 14 160 16

[0111] Table 2 below lists the number of symbols per time slot, the number of time slots per frame, and the number of time slots per subframe according to the SCS in the case of ECP.

[0112] [Table 2]

[0113] SCS (15 * 2^u) <![CDATA[N slot symb > <![CDATA[N frame,u slot > <![CDATA[N subframe,u slot > 60 kHz (u = 2) 12 40 4

[0114] In an NR system, different OFDM(A) parameter sets (e.g., SCS, CP length, etc.) can be configured for multiple cells aggregated for one UE. Thus, the (absolute time) duration of a time resource (e.g., subframe, time slot, or TTI) including the same number of symbols (collectively referred to as a time unit (TU) for convenience) can be configured to be different for the aggregated cells.

[0115] In NR, various parameter sets or SCS can be supported to support various 5G services. For example, with an SCS of 15 kHz, a wide area in the traditional cellular band can be supported, while with an SCS of 30 kHz / 60 kHz, dense urban areas, lower latency, and wide carrier bandwidth can be supported. With an SCS of 60 kHz or higher, a bandwidth greater than 24.25 GHz can be supported to overcome phase noise.

[0116] NR bands can be defined by two types of frequency ranges, FR1 and FR2. The values in each frequency range can be changed. For example, two types of frequency ranges can be given in Table 3. In the NR system, FR1 can be the "range below 6 GHz", and FR2 can be the "range above 6 GHz" known as millimeter wave (mmW).

[0117] [Table 3]

[0118]

[0119]

[0120] As mentioned above, in the NR system, the values in the frequency range can be changed. For example, as listed in Table 4, the range of FR1 can be from 410 MHz to 7125 MHz. That is, FR1 can include bands of 6 GHz (or 5850, 5900, and 5925 MHz) or above. For example, bands of 6 GHz (or 5850, 5900, and 5925 MHz) or above can include unlicensed bands. Unlicensed bands can be used for various purposes, such as vehicle communication (e.g., autonomous driving).

[0121] [Table 4]

[0122] Frequency Range Name Corresponding Frequency Range Subcarrier Spacing (SCS) FR1 410 MHz - 7125 MHz 15, 30, 60 kHz FR2 24250 MHz - 52600 MHz 60, 120, 240 kHz

[0123] Figure 5 Illustrated is the slot structure in an NR frame according to an embodiment of the present disclosure.

[0124] Refer to Figure 5 , a slot includes multiple symbols in the time domain. For example, one slot can include 14 symbols in the NCP case and 12 symbols in the ECP case. Alternatively, one slot can include 7 symbols in the NCP case and 6 symbols in the ECP case.

[0125] A carrier includes multiple sub - carriers in the frequency domain. An RB can be defined by multiple (e.g., 12) consecutive sub - carriers in the frequency domain. A bandwidth part (BWP) can be defined by multiple consecutive (physical) RBs ((P)RBs) in the frequency domain and corresponds to a parameter set (e.g., SCS, CP length, etc.). A carrier can include up to N (e.g., 5) BWPs. Data communication can be performed in the activated BWP. Each element can be referred to as a resource element (RE) in the resource grid, and one complex symbol can be mapped to an RE.

[0126] The radio interface between UEs or between a UE and the network can include L1, L2, and L3. In various embodiments of the present disclosure, L1 can refer to the PHY layer. For example, L2 can refer to at least one of the MAC layer, RLC layer, PDCH layer, or SDAP layer. For example, L3 can refer to the RRC layer.

[0127] Now, a description of V2X or sidelink (SL) communication will be given.

[0128] Figure 6 Illustrated is the radio protocol architecture for SL communication. Specifically, Figure 6 (a) of shows the user - plane protocol stack of NR, and Figure 6 (b) of shows the control - plane protocol stack of NR.

[0129] Next, the sidelink synchronization signal (SLSS) and synchronization information will be described.

[0130] The SLSS, as an SL - specific sequence, can include a primary sidelink synchronization signal (PSSS) and a secondary sidelink synchronization signal (SSSS). The PSSS can be referred to as the sidelink primary synchronization signal (S - PSS), and the SSSS can be referred to as the sidelink secondary synchronization signal (S - SSS). For example, an M - sequence of length 127 can be used for the S - PSS, and a Gold sequence of length 127 can be used for the S - SSS. For example, a UE can detect the initial signal and obtain synchronization by using the S - PSS. For example, a UE can obtain fine synchronization and detect the synchronization signal ID by using the S - PSS and the S - SSS.

[0131] The Physical Sidelink Broadcast Channel (PSBCH) can be a (broadcast) channel that carries the basic (system) information that a UE needs to know first before transmitting and receiving SL signals. For example, the basic information can include information related to SLSS, duplex mode (DM) information, time division duplex (TDD) UL / DL (UL / DL) configuration information, resource pool related information, information about the type of application related to SLSS, subframe offset information, broadcast information, etc. For example, the payload size of the PSBCH can be 56 bits, including 24-bit cyclic redundancy check (CRC), to evaluate the PSBCH performance in NR V2X.

[0132] S-PSS, S-SSS, and PSBCH can be included in a block format that supports periodic transmission (e.g., SL Synchronization Signal (SLSS) / PSBCH block, hereinafter referred to as Sidelink Synchronization Signal Block (S-SSB)). The S-SSB can have the same parameter set (i.e., SCS and CP length) as the Physical Sidelink Control Channel (PSCCH) / Physical Sidelink Shared Channel (PSSCH) in the carrier, and the transmission bandwidth of the S-SSB can be within the (pre-)configured SL BWP. For example, the bandwidth of the S-SSB can be 11 RBs. For example, the PSBCH can span 11 RBs. The frequency position of the S-SSB can be (pre-)set. Therefore, the UE does not need to perform hypothesis detection of the frequency to discover the S-SSB in the carrier.

[0133] In the NR SL system, multiple parameter sets including different SCSs and / or CP lengths can be supported. As the SCS increases, the length of the time resource for S-SSB transmission by the UE can be shortened. Therefore, to ensure the coverage of the S-SSB, the transmitting UE can send one or more S-SSBs to the receiving terminal within one S-SSB transmission period according to the SCS. For example, the number of S-SSBs that the transmitting UE sends to the receiving terminal within one S-SSB transmission period can be pre-configured or configured for the transmitting UE. For example, the S-SSB transmission period can be 160 ms. For example, for all SCSs, an S-SSB transmission period of 160 ms can be supported.

[0134] For example, when the SCS is 15 kHz in FR1, the transmitting UE can send one or two S-SSBs to the receiving UE within one S-SSB transmission period. For example, when the SCS is 30 kHz in FR1, the transmitting UE can send one or two S-SSBs to the receiving UE within one S-SSB transmission period. For example, when the SCS is 60 kHz in FR1, the transmitting UE can send one, two, or four S-SSBs to the receiving UE within one S-SSB transmission period.

[0135] For example, when the SCS in FR2 is 60 kHz, the transmitting UE may send 1, 2, 4, 8, 16, or 32 S-SSBs to the receiving UE within one S-SSB transmission period. For example, when the SCS in FR2 is 120 kHz, the transmitting UE may send 1, 2, 4, 8, 16, 32, or 64 S-SSBs to the receiving UE within one S-SSB transmission period.

[0136] When the SCS is 60 kHz, two types of CPs can be supported. Additionally, the structure of the S-SSB sent from the transmitting UE to the receiving UE may vary according to the CP type. For example, the CP type can be NCP or ECP. Specifically, for example, when the CP type is NCP, the number of symbols to which the PSBCH in the S-SSB sent by the transmitting UE is mapped can be 9 or 8. On the other hand, for example, when the CP type is ECP, the number of symbols to which the PSBCH in the S-SSB sent by the transmitting UE is mapped can be 7 or 6. For example, the PSBCH can be mapped to the first symbol of the S-SSB sent by the transmitting UE. For example, after receiving the S-SSB, the receiving UE may perform an automatic gain control (AGC) operation during the first symbol period of the S-SSB.

[0137] Figure 7 UEs performing V2X or SL communication are illustrated.

[0138] Referring to Figure 7 , in V2X or SL communication, the term "UE" may mainly refer to the user's terminal. However, when a network device such as a BS transmits and receives signals according to the UE-UE communication scheme, the BS can also be regarded as a type of UE. For example, the first UE (UE 1) can be the first device 100, and the second UE (UE 2) can be the second device 200.

[0139] For example, UE 1 may select a resource unit corresponding to a specific resource from a resource pool as a set of resources. Then, UE1 may send an SL signal in the resource unit. For example, UE2 as the receiving UE may be configured with the resource pool in which UE1 can send signals and detect signals from UE1 in the resource pool.

[0140] When UE1 is within the coverage area of the BS, the BS may indicate the resource pool to UE1. Conversely, when UE1 is outside the coverage area of the BS, another UE may indicate the resource pool to UE1, or UE1 may use a predetermined resource pool.

[0141] Generally, the resource pool may include multiple resource units, and each UE may select one or more resource units and send an SL signal in the selected resource units.

[0142] Figure 8 Illustrates resource units for V2X or SL communication.

[0143] Referring Figure 8 , the total frequency resources of the resource pool can be divided into NF frequency resources, and the total time resources of the resource pool can be divided into NT time resources. Therefore, a total of NF×NT resource units can be defined in the resource pool. Figure 8 Illustrates an example in which the resource pool is repeated with a period of NT subframes.

[0144] As Figure 8 illustrated in, a resource unit (e.g., unit #0) can appear periodically and repeatedly. Alternatively, in order to achieve a diversity effect in the time domain or frequency domain, the index of the physical resource unit to which a logical resource unit is mapped can change over time according to a predetermined pattern. In this resource unit structure, the resource pool can refer to the set of resource units available for a UE to send SL signals.

[0145] The resource pool can be divided into several types. For example, each resource pool is classified as follows according to the content of the SL signal transmitted in the resource pool.

[0146] (1) A scheduling assignment (SA) can include information such as the location of the resources for a transmitting UE to send an SL data channel, the modulation and coding scheme (MCS) or multiple-input multiple-output (MIMO) transmission scheme required for data channel demodulation, and the timing advance (TA). The SA can be multiplexed with the SL data in the same resource unit for transmission. In this case, the SA resource pool can refer to the resource pool in which the SA and the SL data are multiplexed for transmission. The SA can be referred to as the SL control channel.

[0147] (2) The SL data channel (PSSCH) can be the resource pool for a transmitting UE to send user data. When the SA and the SL data are multiplexed in the same resource unit for transmission, only the SL data channel other than the SA information can be transmitted in the resource pool for the SL data channel. In other words, the resource elements (REs) used to send the SA information in the individual resource units in the SA resource pool can still be used to send the SL data in the resource pool for the SL data channel. For example, a transmitting UE can send the PSSCH by mapping it to consecutive physical resource blocks (PRBs).

[0148] (3) The discovery channel can be the resource pool for a transmitting UE to send information such as its ID. The transmitting UE can enable neighboring UEs to discover itself on the discovery channel.

[0149] Even when the SL signal has the same content as described above, different resource pools can be used according to the transmission / reception nature of the SL signal. For example, although the SL data channel or discovery message is the same, different resource pools are used for the SL signal according to the SL signal transmission timing determination scheme (e.g., whether the SL signal is transmitted at the reception time of the synchronization reference signal (RS) or at the time obtained by applying a predetermined TA to the reception time), the SL signal resource allocation scheme (e.g., whether the BS allocates the transmission resources of an individual signal to a UE or whether the individual transmitting UE selects its own individual signal transmission resources in the resource pool), the SL signal format (e.g., the number of symbols occupied by each SL signal in a subframe or the number of subframes used to transmit an SL signal), the strength of the signal from the BS, the transmission power of the SL UE, etc.

[0150] SL DRX (Sidelink Discontinuous Reception)

[0151] SideLink supports SL DRX for unicast, multicast, and broadcast. Similar parameters (ON duration, Inactivity timer, Retransmission timer, Period) defined for Uu are defined for SL to determine the SL active time for SL DRX. During the SL active time, the UE performs SCI monitoring for data reception (i.e., the second-stage SCI on the PSCCH and PSSCH). The UE can skip the monitoring of the SCI for data reception during the SL DRX Inactivity time.

[0152] The actual parameters supported for each broadcast type (unicast, multicast, broadcast) are specified in the following subsections.

[0153] The SL active time of the RX UE includes the time when any applicable SL ON duration timer, SL Inactivity timer, or SL Retransmission timer (for any of unicast, multicast, or broadcast) is running. In addition, the time slots associated with the periodic transmissions announced by the TX UE and the time when the UE is expecting a CSI report (for unicast) after a CSI request are also considered as the SL active time of the RX UE.

[0154] The TX UE maintains a set of timers corresponding to the SL DRX timers in the RX UE for each source / destination L2 ID pair for unicast or the destination L2 ID for multicast / broadcast. When data is available for transmission to one or more RX UEs configured with SL DRX, the TX UE selects resources considering the active time of the RX UE determined by the timers maintained at the TX UE.

[0155] For unicast, SL DRX is configured per source L2 ID and destination L2 ID pair.

[0156] The UE maintains a set of SL DRX timers for each direction of each pair of source L2 ID and destination L2 ID. The SL DRX configuration for a pair of source / destination L2 IDs in one direction can be negotiated between UEs at the AS layer. For the SL DRX configuration in each direction, one UE is the TX UE and the other is the RX UE:

[0157] - The RX UE can send auxiliary information to the TX UE, which includes its desired on-duration timer, SL DRX start offset, and SL DRX period, and the mode 2 TX UE can use it to determine the SL DRX configuration of the RX UE.

[0158] - Regardless of whether the auxiliary information is provided, the TX UE in RRC_IDLE / RRC_INACTIVE / OOC or in RRC_CONNECTED and using mode 2 resource allocation determines the SL DRX configuration of the RX UE. For the TX UE in RRC_CONNECTED and using mode 1 resource allocation, the SL DRX configuration of the RX UE is determined by the serving gNB of the TX UE.

[0159] - The TX UE sends the SL DRX configuration to be used by the RX UE.

[0160] - The RX UE can accept or reject the SL DRX configuration.

[0161] The default SL DRX configuration for multicast / broadcast can be used for DCR messages.

[0162] When the TX UE is in RRC_CONNECTED, the TX UE can report the received auxiliary information to its serving gNB, and after receiving the SL DRX configuration in the dedicated RRC signaling from the gNB, send the SL DRX configuration to the RX UE. When the RX UE is in RRC_CONNECTED, the RX UE can report the received SL DRX configuration to its serving gNB, e.g., for the alignment of Uu and SL DRX configurations.

[0163] The SL on-duration timer, SL inactivity timer, SL HARQ RTT timer, and SL HARQ retransmission timer are supported in unicast. At the RX UE, the SL HARQ RTT timer and SL HARQ retransmission timer are maintained per SL process. In addition to the (pre)-configured values for each of these timers, when the SCI indicates more than one transmission resource, the SL HARQ RTT timer value can be derived based on the retransmission resource timing.

[0164] The SL DRX MAC CE is introduced only for SL DRX operation in unicast.

[0165] For multicast / broadcast, the SL DRX is configured jointly among multiple UEs based on the QoS profile and the destination L2 ID. Multiple SL DRX configurations can be supported for each multicast / broadcast.

[0166] For multicast, the SL on-duration timer, SL inactivity timer, SL HARQ RTT, and SL retransmission timer are supported. For broadcast, only the SL on-duration timer is supported. The SL DRX period, SL on-duration, and SL inactivity timer (only for multicast) are configured per QoS profile. The start offset and slot offset of the SL DRX period are determined based on the destination L2 ID. The SL HARQ RTT timer (only for multicast) and SL HARQ retransmission timer (only for multicast) are not configured per QoS profile or per destination L2 ID. For multicast, the RX UE maintains the SL inactivity timer for each destination L2 ID, and if multiple SL inactivity timer values associated with different QoS profiles are configured for that L2 ID, the maximum SL inactivity timer value is selected. For multicast and broadcast, when multiple QoS profiles are configured for each destination L2 ID, the RX UE maintains a single SL DRX period (selected as the minimum SL DRX period of any QoS profile for that L2 ID) and a single SL on-duration (selected as the maximum SL on-duration of any QoS profile for that L2 ID).

[0167] For multicast, at the RX UE, the SL HARQ RTT timer and SL retransmission timer are maintained per SL process. The SL HARQ RTT timer can be set to different values to support both HARQ-enabled transmissions and HARQ-disabled transmissions.

[0168] For QoS profiles not mapped to any non-default SL DRX configuration, the common default SL DRX configuration between multicast and broadcast can be used.

[0169] The TX UE and RX UE within the coverage in RRC_IDLE / RRC_INACTIVE obtain their SL DRX configuration from the SIB. The UE (TX or RX) in RRC_CONNECTED can obtain the SL DRX configuration from the SIB or from dedicated RRC signaling during handover. For out-of-coverage scenarios, the SL DRX configuration is obtained from pre-configuration.

[0170] For multicast, when the TX UE receives new data with the same destination L2 ID, it restarts the timer corresponding to the SL inactive timer for that destination L2 ID (for determining the allowable transmission time).

[0171] A TX profile is introduced to ensure compatibility of multicast and broadcast transmissions between UEs that support / do not support the SL DRX feature. The TX profile is provided by the upper layer to the AS layer and identifies one or more sidelink function groups. The TX UE assumes SL DRX for the RX UE only if the associated TX profile corresponds to support for SL DRX. If all destination L2 IDs of interest have an associated TX profile corresponding to support for SL DRX, the RX UE determines to use SL DRX.

[0172] For unicast, multicast, and broadcast, alignment of Uu DRX and SL DRX for UEs in RRC_CONNECTED is supported. Alignment of Uu DRX and SL DRX at the same UE is supported. In addition, for mode 1 scheduling, alignment of Uu DRX of the TX UE and SL DRX of the RX UE is supported.

[0173] The alignment may include full or partial temporal overlap between Uu DRX and SL DRX. For an SL RX UE in RRC_CONNECTED, the alignment is implemented by the gNB.

[0174] The MAC entity can be configured via RRC to have an SL DRX feature that controls the SCI (i.e., first-phase SCI and second-phase SCI) monitoring activity of the UE for unicast, multicast, and broadcast. When operating with SL DRX, the MAC entity shall also monitor the SCI (i.e., first-phase SCI and second-phase SCI) according to the requirements found in other clauses of this specification.

[0175] RRC controls sidelink DRX operation by configuring the following parameters:

[0176] - sl-drx-onDurationTimer: The duration at the start of the SL DRX cycle;

[0177] - sl-drx-SlotOffset: The delay before starting the sl-drx-onDurationTimer;

[0178] -sl-drx-InactivityTimer (except for broadcast transmissions): The duration after the first time slot in which an SCI (i.e., the first-phase SCI and the second-phase SCI) is received (where the SCI indicates a new SL transmission for the MAC entity);

[0179] -sl-drx-RetransmissionTimer (for each sidelink procedure except for broadcast transmissions): The maximum duration until an SL retransmission is received;

[0180] -sl-drx-StartOffset: The time slot at which the SL DRX cycle starts;

[0181] -sl-drx-Cycle: The sidelink DRX cycle;

[0182] -sl-drx-HARQ-RTT-Timer (for each sidelink procedure except for broadcast transmissions): The minimum duration before the MAC entity expects an SL HARQ retransmission.

[0183] When SL DRX is configured, the active time includes the following times:

[0184] - The sl-drx-onDurationTimer or the sl-drx-InactivityTimer is running; or

[0185] - The sl-drx-RetransmissionTimer is running; or

[0186] - The period of sl-LatencyBoundCSI-Report configured by RRC in the case where an SL-CSI report MAC CE is not received; or

[0187] - The time between the transmission of an SL-CSI report request and the reception of an SL-SCI report MAC CE in the case where an SL-CSI report MAC CE is received; or

[0188] - The time slots associated with the periodic transmissions announced by the UE that transmits SL-SCH data.

[0189] When one or more SL DRXs are configured, the MAC entity shall:

[0190] 1> If multiple SL DRX cycles are mapped to multiple SL-QoS-profiles of the destination layer-2 ID and the concerned broadcast types are associated with multicast and broadcast:

[0191] 2> Select sl-drx-Cycle, where the length of the sl-drx-Cycle is the shortest among multiple SL DRX cycles mapped to multiple SL-QoS-Profiles associated with the destination layer-2 ID:

[0192] 2> Select sl-drx-onDurationTimer, where the length of the sl-drx-onDurationTimer is the longest among multiple SL DRX on-duration timers mapped to multiple SL-QoS-Profiles associated with the destination layer-2 ID.

[0193] 1> If the sl-drx-HARQ-RTT-Timer expires:

[0194] 2> If the data of the corresponding sidelink process is not successfully decoded, or if HARQ feedback (i.e., negative acknowledgment) is not sent for unicast due to UL / SL prioritization:

[0195] 3> Start the sl-drx-RetransmissionTimer for the corresponding sidelink process in the first slot after the sl-drx-HARQ-RTT-Timer expires.

[0196] When the broadcast type is multicast or broadcast as indicated by the upper layer, sl-drx-StartOffset and sl-drx-SlotOffset are obtained according to the following formula:

[0197] sl-drx-StartOffset (ms) = destination layer-2 ID modulo sl-drx-Cycle (ms).

[0198] sl-drx-SlotOffset (ms) = destination layer-2 ID modulo sl-drx-onDurationTimer (ms).

[0199] 1> If the SL DRX cycle is used and [(DFNX10) + subframe number] modulo (sl-drx-Cycle) = sl-drx-StartOffset:

[0200] 2> Start the sl-drx-onDurationTimer after sl-drx-SlotOffset from the start of the subframe.

[0201] 1> If the SL DRX is in the active time:

[0202] 2> Monitor SCI (i.e., the first-phase SCI and the second-phase SCI) in this SL DRX.

[0203] 2> If the SCI indicates a new SL transmission:

[0204] 3> If the source layer-1 ID of the SCI is equal to the 8 LSBs of the expected destination layer-2 ID and the destination layer-1 ID of the SCI is equal to the 8 LSBs of the expected source layer-2 ID, and the broadcast type indicator in the SCI is set to unicast:

[0205] 4> After the first time slot of the SCI reception, start or restart the sl-drx-InactivityTimer for the corresponding source layer-2 ID and destination layer-2 ID.

[0206] 3> If the destination layer-1 ID of the SCI (i.e., the second-phase SCI) is equal to the 8 LSBs of the expected destination layer-1 ID, and the broadcast type indicator in the SCI is set to multicast:

[0207] 4> Select the sl-drx-InactivityTimer, where the length of the sl-drx-InactivityTimer is the largest one among the multiple SL DRX inactivity timers mapped to the multiple SL-QoS-Profile of the destination layer-2 ID associated with the destination layer-1 ID of the SCI; and

[0208] 4> After the first time slot of the SCI reception, start or restart the sl-drx-InactivityTimer for the corresponding destination layer-2 ID.

[0209] 2> If the SCI indicates an SL transmission:

[0210] 3> If the PSFCH resource is not configured for the SL grant associated with the SCI:

[0211] 4> Start the sl-drx-HARQ-RTT-Timer for the corresponding sidelink process in the time slot after the end of the PSSCH transmission (i.e., the currently received PSSCH).

[0212] 3> If the PSFCH resource is configured for the SL grant associated with the SCI:

[0213] 4> If HARQ feedback is enabled by the SCI and the broadcast type indicator in the SCI is set to unicast; or 4> If HARQ feedback is enabled by the SCI and the broadcast type indicator in the SCI is set to multicast, and an acknowledgement-nack is selected;

[0214] 5> Start the sl-drx-HARQ-RTT-Timer for the corresponding sidelink process in the first time slot after the transmission of the corresponding PSFCH carrying the SL HARQ feedback; or

[0215] 5> When the SL HARQ feedback is not sent due to UL / SL prioritization, start the sl-drx-HARQ-RTT-Timer for the corresponding sidelink process in the first time slot after the corresponding PSFCH resource for the SL HARQ feedback ends;

[0216] 4> If HARQ feedback is enabled by SCI and the broadcast type indicator in the SCI is set to multicast, and only negative acknowledgments are selected;

[0217] 5> Start the sl-drx-HARQ-RTT-Timer for the corresponding sidelink process in the first time slot after the transmission of the corresponding PSFCH carrying the SL HARQ feedback; or

[0218] 5> When the SL HARQ feedback is not sent due to UL / SL prioritization, start the sl-drx-HARQ-RTT-Timer for the corresponding sidelink process in the first time slot after the corresponding PSFCH resource for the SL HARQ feedback ends; or

[0219] 5> When the SL HARQ feedback is a positive acknowledgment, start the sl-drx-HARQ-RTT-Timer for the corresponding sidelink process in the first time slot after the corresponding PSFCH resource for the SL HARQ feedback ends.

[0220] 4> If HARQ feedback is disabled by SCI and resources for one or more retransmission opportunities are not scheduled in the SCI:

[0221] 5> Start the sl-drx-HARQ-RTT-Timer for the corresponding sidelink process in the time slot after the PSFCH resource ends.

[0222] 4> If HARQ feedback is disabled by SCI and resources for one or more retransmission opportunities are scheduled in the SCI:

[0223] 5> Start the sl-drx-HARQ-RTT-Timer for the corresponding sidelink process in the time slot after the PSSCH transmission (i.e., the currently received PSSCH) ends.

[0224] Note: When the SCI indicates the next retransmission resource, the sl-drx-HARQ-RTT-Timer is derived based on the retransmission resource timing (i.e., the next immediate retransmission resource indicated in the SCI). When the SCI does not indicate the next retransmission resource, the UE uses the configured sl-drx-HARQ-RTT-Timer.

[0225] 3> Stop the sl-drx-RetransmissionTimer for the corresponding sidelink process.

[0226] 1> If an SL DRX command MAC CE for a unicast source layer-2 ID and destination layer-2 ID pair is received:

[0227] 2> Stop the sl-drx-onDurationTimer for the unicast source layer-2 ID and destination layer-2 ID pair;

[0228] 2> Stop the sl-drx-InactivityTimer for the unicast source layer-2 ID and destination layer-2 ID pair.

[0229] UE-to-UE coordination (IUC)

[0230] The SL UE can support UE-to-UE coordination (IUC) in mode 2, whereby UE-A sends information about resources to UE-B, and then UE-B uses this information for resource (re)selection. The following UE-to-UE coordination schemes are supported:

[0231] - IUC scheme 1, where the coordination information sent from UE-A to UE-B is the preferred and / or non-preferred resources for UE-B's transmission, and

[0232] - IUC scheme 2, where the coordination information sent from UE-A to UE-B is the existence of an expected / potential resource conflict on the resources indicated by UE-B's SCI.

[0233] In Solution 1, the IUC can be triggered by an explicit request from UE-B or by a condition at UE-A. UE-A determines the set of resources reserved by other UEs or the time slots in which UE-A does not expect to perform SL reception from UE-B due to half-duplex operation when UE-A is the intended receiver of UE-B. UE-A uses these resources as a set of non-preferred resources or excludes these resources to determine the set of preferred resources, and sends the preferred / non-preferred resources to UE-B. The resources for (re)selection at UE-B can be based on both the sensing result of UE-B (if available) and the coordination information received from UE-A, or it can be based only on the coordination information received from UE-A. For Solution 1, MAC CE and the second-phase SCI, or only MAC CE can be used to send the IUC. Support for explicit requests and reports for the IUC in unicast mode is provided.

[0234] In Solution 2, UE-A determines the expected / potential resource conflicts within the resources indicated by the SCI of UE-B as the resources reserved by other UEs and identified by UE-A as fully / partially overlapping with the resources indicated by the SCI of UE-B, or as the time slots in which UE-A is the intended receiver of UE-B and does not expect to perform SL reception on those time slots due to half-duplex operation. UE-B uses the conflict resources to determine the resources to be reselected and excludes the conflict resources from the reselected resources. For Solution 2, the PSFCH is used to send the IUC.

[0235] The sidelink UE-to-UE coordination request (SL-IUC Req) transmission procedure is used to trigger a peer UE to send sidelink UE-to-UE coordination information.

[0236] The sidelink UE-to-UE coordination information (SL-IUC Info) reporting procedure is used to provide UE-to-UE coordination information to a peer UE.

[0237] -sl-LatencyBoundIUC-Report, which is maintained for each PC5-RRC connection.

[0238] The MAC entity maintains the sl-IUC-ReportTimer for each pair of source layer-2 ID and destination layer-2 ID corresponding to a PC5-RRC connection. The sl-IUC-ReportTimer is used for the SL-IUC information reporting UE to follow the latency requirement triggered by the IUC-Information signaling. The value of the sl-IUC-ReportTimer is the same as the latency requirement of the SL-IUC information in the sl-LatencyBoundIUC-Report configured through RRC.

[0239] The MAC entity shall, for each pair of source layer-2 ID and destination layer-2 ID corresponding to a PC5-RRC connection that has been established by the upper layer:

[0240] 1> If the SL-IUC information report has been triggered by an SL-IUC request MAC CE (and / or SCI) and has not been cancelled:

[0241] 2> If the sl-IUC-ReportTimer for the triggered SL-IUC information report is not running:

[0242] 3> Start the sl-IUC-ReportTimer.

[0243] 2> If the sl-IUC-ReportTimer for the triggered SL-IUC information report expires:

[0244] 3> Cancel the triggered SL-IUC information report.

[0245] 2> Otherwise, if the MAC entity has SL resources allocated for new transmissions and, due to logical channel prioritization, the SL-SCH resources can accommodate the SL-IUC information MAC CE and its sub-header:

[0246] 3> Indicate the multiplexing and assembly process to generate the sidelink UE-to-UE coordination information MAC CE, as defined in clause 6.1.3.35;

[0247] 3> Stop the sl-IUC-ReportTimer for the triggered SL-IUC information report;

[0248] 3> Cancel the triggered SL-IUC information report.

[0249] Figure 9 The UE-to-UE coordination information MAC CE is illustrated.

[0250] The UE-to-UE coordination information MAC CE is identified by a MAC sub-header with an LCID as specified in Table 5.

[0251] [Table 5]

[0252]

[0253] The priority of the UE-to-UE coordination information MAC CE is fixed at '1'. It has a variable size and has the following fields:

[0254] - RT: This field indicates the resource set type, i.e., the preferred resource set or the non-preferred resource set, as the codepoint value of the SCI format 2 - CresourceSetType field.

[0255] -RSL: This field indicates the position of the reference time slot as the code point value of the referenceSlotLocation field in SCI format 2-C. The length of this field is 17 bits. If the length of the referenceSlotLocation field in SCI format 2-C is shorter than 17 bits, this field contains the referenceSlotLocation field using the LSB bits;

[0256] -LSIi: This field indicates the lowest subchannel index of the first resource position of each TRIV as the code point value of the lowest index field in SCI format 2-C. LSI0 indicates the lowest subchannel index of the first resource position of the TRIV within the first resource combination, LSI1 indicates the lowest subchannel index of the first resource position of the TRIV within the second resource combination, and so on. The length of this field is 5 bits. If the length of the lowest index field in SCI format 2-C is shorter than 5 bits, this field contains the lowest index field using the LSB bits;

[0257] -RCi: This field indicates the resource combination as the code point value of the resourceCombination field in SCI format 2-C. RC0 indicates the first resource combination, RC1 indicates the second resource combination, and so on. [The maximum number of included resource combinations is 8]. The length of this field is 26 bits. If the length of the resourceCombination field in SCI format 2-C is shorter than 26 bits, this field contains the resourceCombination field using the LSB bits;

[0258] -First resource position i - 1: This field indicates the first resource position as the code point value of the firstResourceLocation field in SCI format 2-C. First resource position 0 indicates the first resource position of the second resource combination, first resource position 1 indicates the first resource position of the third resource combination, and so on. The length of this field is 13 bits. If the length of the firstResourceLocation field in SCI format 2-C is shorter than 13 bits, this field contains the firstResourceLocation field using the LSB bits;

[0259] -R: Reserved bit, set to 0.

[0260] Figure 10 Illustrates the inter-UE coordination request MAC CE.

[0261] The inter-UE coordination request MAC CE is identified by the MAC subheader with the LCID specified in Table 5. The priority of the inter-UE coordination request MAC CE is fixed at '1'. It has a variable size and has the following fields:

[0262] - RT: This field indicates the resource set type, i.e., the preferred resource set or the non-preferred resource set, as the code point value of the SCI format 2-C resourceSetType field.

[0263] - RP: This field indicates the resource reservation period, as the code point value of the SCI format 2-C resourceReservationPeriod field. The length of this field is 4 bits. If the length of the resourceReservationPeriod field in SCI format 2-C is shorter than 4 bits, then this field contains the resourceReservationPeriod field using the LSB bits;

[0264] - Priority: This field indicates the priority, as the code point value of the SCI format 2-C priority field. The length of this field is 3 bits;

[0265] - RSWL: This field indicates the resource selection window location, as the code point value of the SCI format 2-C resourceSelectionWindowLocation field. The length of this field is 34 bits. If the length of the resourceSelectionWindowLocation field in SCI format 2-C is shorter than 34 bits, then this field contains the resourceSelectionWindowLocation field using the LSB bits;

[0266] - Number of subchannels: This field indicates the number of subchannels, as the code point value of the SCI format 2-C numberOfSubchannel field. The length of this field is 5 bits. If the length of the numberOfSubchannel field in SCI format 2-C is shorter than 5 bits, then this field contains the numberOfSubchannel field using the LSB bits;

[0267] - R: Reservation bit, set to 0.

[0268] Sidelink Relay

[0269] Side link relay is introduced to support the 5G ProSe UE-to-network relay (U2N relay) function, thus providing a connection to the network for U2N remote UEs. Both L2 and L3 U2N relay architectures are supported. The L3 U2N relay architecture is transparent to the serving RAN of the U2N relay UE, except for controlling the side link resources.

[0270] Relay discovery: The AS function enables 5G ProSe UE-to-network relay discovery, using NR technology without traversing any network nodes.

[0271] U2N Relay UE: A UE that provides the function of supporting the connection of a U2N remote UE to the network.

[0272] U2N Remote UE: A UE that communicates with the network via a U2N Relay UE.

[0273] Uplink: The direction towards the parent node in the IAB topology.

[0274] Uu Relay RLC Channel: The RLC channel between the L2 U2N Relay UE and the gNB, which is used to transmit packets for L2 UE-to-network relay over the Uu.

[0275] The U2N Relay UE shall be in RRC_CONNECTED to perform the relay of unicast data.

[0276] For L2 U2N relay operation, the following RRC state combinations are supported:

[0277] - Both the U2N Relay UE and the U2N Remote UE shall be in RRC_CONNECTED to perform the sending / receiving of unicast data for relay.

[0278] - The U2N Relay UE can be in RRC_IDLE, RRC_INACTIVE, or RRC_CONNECTED as long as all U2N Remote UEs connected to the U2N Relay UE are in RRC_INACTIVE or RRC_IDLE.

[0279] For L2 U2N relay, the U2N Remote UE can only be configured to use resource allocation mode 2 for the data to be relayed.

[0280] A single unicast link is established between an L2 U2N Relay UE and an L2 U2N Remote UE. The traffic of the U2N Remote UE via a given U2N Relay UE and the traffic of the U2N Relay UE shall be separated in different Uu RLC channels over the Uu.

[0281] Protocol Stack for SL Relay

[0282] Figure 11 Illustrated are (a) the user plane protocol stack and (b) the control plane protocol stack for L2 UE-to-network relay.

[0283] In Figure 11 of (a) and Figure 11The protocol stacks for the user plane and control plane of the L2 U2N relay architecture are presented in (b). The SRAP sublayer is placed above the RLC sublayer of both the CP and UP at both the PC5 interface and the Uu interface. UuSDAP, PDCP, and RRC are terminated between the L2 U2N remote UE and the gNB, while SRAP, RLC, MAC, and PHY are terminated in each hop (i.e., the link between the L2 U2N remote UE and the L2 U2N relay UE and the link between the L2 U2N relay UE and the gNB).

[0284] For L2 U2N relay, the SRAP sublayer on the PC5 hop is only for the purpose of bearer mapping. The SRAP sublayer does not exist on the PC5 hop for relaying messages of the L2 U2N remote UE on the BCCH and PCCH. For messages of the L2 U2N remote UE regarding SRB0, the SRAP sublayer does not exist on the PC5 hop, but the SRAP sublayer exists on the Uu hop for both DL and UL.

[0285] For L2 U2N relay, for the uplink:

[0286] - The Uu SRAP sublayer supports UL bearer mapping between the ingress PC5 relay RLC channel for relay and the egress Uu relay RLC channel on the Uu interface of the L2 U2N relay UE. For uplink relay traffic, different end-to-end RBs (SRB or DRB) of the same remote UE and / or different remote UEs can be multiplexed on the same Uu relay RLC channel.

[0287] - The Uu SRAP sublayer supports the identification of the L2 U2N remote UE for UL traffic. The identification information of the L2 U2N remote UE Uu radio bearer and the local remote UE ID are included in the Uu SRAP header at UL so that the gNB can associate the received packets with the correct PDCP entity associated with the Uu radio bearer of the remote UE.

[0288] - The PC5 SRAP sublayer at the L2 U2N remote UE supports UL bearer mapping between the remote UE Uu radio bearer and the egress PC5 relay RLC channel.

[0289] For L2 U2N relay, for the downlink:

[0290] - The Uu SRAP sublayer supports DL bearer mapping at the gNB to map the end-to-end radio bearers (SRBs, DRBs) of the remote UE to the Uu relay RLC channels via the relay UE Uu interface. The Uu SRAP sublayer supports DL bearer mapping and data multiplexing between one L2 U2N remote UE and / or multiple end-to-end radio bearers (SRBs or DRBs) of different L2 U2N remote UEs and one Uu relay RLC channel on the relay UE Uu interface.

[0291] - The Uu SRAP sublayer supports remote UE identification for DL traffic. The identification information of the remote UE Uu radio bearer and the local remote UE ID are included by the gNB in the DL Uu SRAP header so that the relay UE can map the packets received from the remote UE Uu radio bearer to its associated PC5 relay RLC channel.

[0292] - The PC5 SRAP sublayer at the relay UE supports DL bearer mapping between the ingress Uu relay RLC channel and the egress PC5 relay RLC channel.

[0293] - The PC5 SRAP sublayer at the remote UE associates the received packets of a specific PDCP entity associated with the correct Uu radio bearer of the remote UE based on the identification information included in the Uu SRAP header.

[0294] The local remote UE ID is included in both the PC5 SRAP header and the Uu SRAP header. The L2 U2N relay UE is configured by the gNB with the local remote UE ID to be used in the SRAP header. The remote UE obtains the local remote ID from the gNB via Uu RRC messages (including RRCSetup, RRCReconfiguration, RRCResume, and RRCReestablishment). Uu DRBs and Uu SRBs are mapped to different PC5 relay RLC channels and Uu relay RLC channels in both the PC5 hop and the Uu hop.

[0295] The gNB is responsible for avoiding conflicts in the use of the local remote UE ID. The gNB can update the local remote UE ID by sending an updated local remote ID to the relay UE via the RRCReconfiguration message. The serving gNB can perform local remote UE ID updates independently of the PC5 unicast link L2 ID update process.

[0296] Figure 12 The protocol stack for the discovery message for UE-to-network relay is illustrated.

[0297] Support is provided for using the Model A discovery model and the Model B discovery model for U2N relay discovery. InFigure 12 The protocol stack for discovery is presented.

[0298] The U2N remote UE can perform relay discovery message transmission and can monitor relay discovery messages on the sidelink when in RRC_IDLE, RRC_INACTIVE, or RRC_CONNECTED. The network can broadcast a threshold, which is used by the U2N remote UE to determine whether it can send a relay discovery solicitation message to the U2N relay UE.

[0299] The U2N relay UE can perform relay discovery message transmission and can monitor relay discovery messages on the sidelink when in RRC_IDLE, RRC_INACTIVE, or RRC_CONNECTED. The network can broadcast a maximum Uu RSRP threshold, a minimum Uu RSRP threshold, or both, which the U2N relay UE uses to determine whether it can send a relay discovery message to the U2N remote UE.

[0300] The network can use broadcast or dedicated signaling to provide relay discovery configuration for relay discovery. In addition, the U2N remote UE and the U2N relay UE can use pre-configuration for relay discovery.

[0301] The resource pool for NR sidelink communication can be used for relay discovery, or the network can configure a resource pool dedicated to relay discovery. The resource pool dedicated to relay discovery can be configured simultaneously with the resource pool for NR sidelink communication in system information, dedicated signaling, and / or pre-configuration. Whether to configure a resource pool dedicated to relay discovery is based on network implementation. If a resource pool dedicated to relay discovery is configured, only those resource pools dedicated to relay discovery should be used for relay discovery. If only the resource pool for NR sidelink communication is configured, all configured transmission resource pools can be used for relay discovery and sidelink communication.

[0302] For U2N remote UEs that are already connected to the network via the U2N relay UE (including both in-coverage and out-of-coverage cases), only resource allocation mode 2 is used for discovery message transmission.

[0303] Relay discovery reuses the NR sidelink resource allocation principle for in-coverage U2N relay UEs and for both in-coverage and out-of-coverage U2N remote UEs.

[0304] The sidelink power control for transmitting relay discovery messages is the same as that for NR sidelink communication.

[0305] No encryption or integrity protection in the PDCP layer is applied to relay discovery messages.

[0306] The UE can determine whether the gNB supports relay discovery, non-relay discovery, or both from SIB12.

[0307] Relay Selection / Reselection

[0308] The U2N remote UE performs radio measurements at the PC5 interface and uses them together with higher layer criteria for U2N relay selection and reselection. When there is no unicast PC5 connection between the U2N relay UE and the U2N remote UE, the U2N remote UE uses the SD-RSRP measurement to evaluate whether the PC5 link quality towards the U2N relay UE meets the relay selection criteria.

[0309] For relay reselection, when there is data transmission from the U2N relay UE to the U2N remote UE, the U2N remote UE uses the SL-RSRP measurement towards the serving U2N relay UE for relay reselection trigger evaluation, and in the case of no data transmission from the U2N relay UE to the U2N remote UE, whether to use SL-RSRP or SD-RSRP for relay reselection trigger evaluation depends on the UE implementation.

[0310] If the PC5 link quality towards the U2N relay UE measured by the U2N remote UE exceeds the configured threshold (pre-configured or provided by the gNB), then this U2N relay UE is considered suitable in terms of radio criteria. The U2N remote UE searches for suitable U2N relay UE candidates that meet all AS layer and higher layer criteria (see TS23.304[xx]). If there are multiple such suitable U2N relay UEs, one U2N relay UE is selected among them depending on the U2N remote UE implementation. For L2 U2N relay (re)selection, the PLMN ID and cell ID can be used as additional AS criteria.

[0311] The U2N remote UE triggers U2N relay selection in the following cases:

[0312] - The direct Uu signal strength of the current serving cell of the U2N remote UE is lower than the configured signal strength threshold;

[0313] - Indicated by the upper layer of the U2N remote UE.

[0314] The U2N remote UE can trigger U2N relay reselection in the following cases:

[0315] - The PC5 signal strength of the current U2N relay UE is lower than the (pre)-configured signal strength threshold;

[0316] - Cell (re)selection, handover, or Uu RLF has been indicated by the U2N relay UE via PC5-RRC signaling;

[0317] - When the remote UE receives a PC5-S link release message from the U2N relay UE;

[0318] - When the U2N remote UE detects a PC5 RLF;

[0319] - Indicated by the upper layer.

[0320] For L2 U2N remote UEs and L3 U2N remote UEs in RRC_IDLE / INACTIVE, the cell (re)selection process and the relay (re)selection process run independently. If both a suitable cell and a suitable U2N relay UE are available, the selection of the cell or the U2N relay UE depends on the UE implementation. The L3 U2N remote UE can select both a cell and a U2N relay UE simultaneously, and this depends on the implementation of the L3 U2N remote UE.

[0321] For both L2 and L3 U2N relay UEs in RRC_IDLE / INACTIVE, PC5-RRC messages are used to notify their connected remote UEs when the U2N relay UE selects a new cell. When the L2 / L3 U2N relay UE performs a handover or detects a Uu RLF, the PC5-RRC message is also used to notify its connected L2 or L3 U2N remote UE. After receiving the PC5 RRC message for notification, whether to release or maintain the unicast PC5 link depends on the U2N remote UE implementation. If the U2N remote UE decides to release the unicast PC5 link, it triggers the L2 release process and can perform relay reselection.

[0322] Control Plane Procedures for L2 U2N Relay

[0323] 1) RRC connection management

[0324] The U2N remote UE needs to establish its own PDU session / DRB with the network before user plane data transmission.

[0325] Before the U2N remote UE establishes a Uu RRC connection with the network via the U2N relay UE, the NR V2X PC5 unicast link establishment process can be reused to establish a secure unicast link between the U2N remote UE and the U2N relay UE.

[0326] The establishment of the Uu SRB1 / SRB2 and DRB of the U2N remote UE is subject to the Uu configuration process of the L2 UE to the network relay.

[0327] Figure 13 Illustrates the process for L2 U2N remote UE connection establishment. Figure 13 The following high-level connection establishment process in applies to L2 U2N relay:

[0328] 1. The U2N remote and U2N relay UEs perform the discovery process and establish a PC5-RRC connection using the NR V2X process.

[0329] 2. The U2N remote UE uses the specified PC5 relay RLC channel configuration to send the first RRC message (i.e., RRCSetupRequest) via the relay UE for its connection establishment with the gNB. If the U2N relay UE is not in RRC_CONNECTED, it needs to perform its own connection establishment after receiving the message on the specified PC5 relay RLC channel. During the RRC connection establishment process of the relay UE, the gNB can configure the SRB0 relay Uu relay RLC channel for the U2N relay UE. The gNB responds to the U2N remote UE with an RRCSetup message. The RRCSetup message is sent to the U2N remote UE using the SRB0 relay channel on Uu and the specified PC5 relay RLC channel on PC5.

[0330] 3. The gNB and the U2N relay UE perform the relay channel establishment process on Uu. According to the configuration from the gNB, the U2N relay / remote UE establishes the PC5 relay RLC channel for relaying SRB1 towards the U2N remote / relay UE on PC5.

[0331] 4. The RRCSetupComplete message is sent by the U2N remote UE to the gNB via the U2N relay UE using the SRB1 relay channel on PC5 and the SRB1 relay channel configured for the U2N relay UE on Uu. Then, the U2N remote UE makes an RRC connection on Uu.

[0332] 5. The U2N remote UE and the gNB establish security following the Uu process, and the security messages are forwarded by the U2N relay UE.

[0333] 6. The gNB sends an RRCReconfiguration message to the U2N remote UE via the U2N relay UE to configure SRB2 / DRB for relay purposes. The U2N remote UE sends an RRCReconfigurationComplete message to the gNB via the U2N relay UE as a response. In addition, the gNB configures additional Uu relay RLC channels between the gNB and the U2N relay UE and PC5 relay RLC channels between the U2N relay UE and the U2N remote UE for relaying traffic.

[0334] 2) Radio Link Failure

[0335] When the U2N remote UE is connected to the gNB via the U2N relay UE, the U2N remote UE in RRC_CONNECTED suspends Uu RLM.

[0336] The U2N relay UE declares a radio link failure (RLF) following the same criteria.

[0337] After declaring the RLF, the U2N relay UE also takes the following actions on top of the actions:

[0338] - The PC5-RRC message can be used to send an indication to the connected U2N remote UE, which can trigger RRC connection re-establishment for the U2N remote UE.

[0339] After detecting a PC5 RLF, the U2N remote UE can trigger connection re-establishment.

[0340] 3) RRC connection re-establishment

[0341] The U2N remote UE can perform the following actions during the RRC connection re-establishment process:

[0342] - If only suitable cells are available, the U2N remote UE initiates the RRC re-establishment process towards the suitable cell;

[0343] - If only suitable U2N relay UEs are available, the U2N remote UE initiates the RRC re-establishment process towards the serving cell of the suitable relay UE;

[0344] - If both suitable cells and suitable relays are available, the U2N remote UE can choose either one based on the implementation to initiate the RRC re-establishment process.

[0345] 4) RRC connection recovery

[0346] The RRC connection recovery mechanism is applied to the U2N remote UE.

[0347] 5) System information

[0348] The U2N remote UE within the coverage area is allowed to obtain any necessary SIBs through the Uu interface, regardless of its PC5 connection to the relay UE. The U2N remote UE can also receive system information from the relay UE after the PC5 connection with the U2N relay UE is established.

[0349] A U2N remote UE in the RRC_CONNECTED state can request SIBs via a U2N relay UE using the on-demand SIB framework. A U2N remote UE in the RRC_IDLE or RRC_INACTIVE state can notify the U2N relay UE of the types of SIBs it requests via a PC5-RRC message. The U2N relay UE then triggers an on-demand SI / SIB acquisition process according to its own RRC state (if necessary) and sends the acquired SI / SIBs to the U2N remote UE via PC5-RRC.

[0350] A U2N remote UE in the RRC_IDLE or RRC_INACTIVE state can request any SIBs that the U2N remote UE is required to use (e.g., for relay purposes) (from the U2N relay UE or the network). For the SIBs that the U2N remote UE has requested from the U2N relay UE, the U2N relay UE forwards them again in case of any updates to the requested SIBs. In the case of a U2N remote UE in the RRC_CONNECTED state, the network is responsible for sending updated SIBs to the U2N remote UE when the SIBs are updated. The U2N remote UE cancels the SI request to the U2N relay UE when entering the RRC_CONNECTED state.

[0351] For SIB1 forwarding, for a U2N remote UE, the U2N relay UE supports both request-based delivery (i.e., the SIB1 request of the U2N remote UE) and unsolicited forwarding, and which one to use depends on the U2N relay UE implementation. If SIB1 changes, for a U2N remote UE in the RRC_IDLE or RRC_INACTIVE state, the U2N relay UE always forwards SIB1.

[0352] For an L2 U2N remote UE in the RRC_IDLE or RRC_INACTIVE state, the L2 U2N relay UE does not forward short messages on the Uu interface to the L2 U2N remote UE. The L2 U2N relay UE can forward PWS SIBS to the connected L2 U2N remote UE.

[0353] The L2 U2N relay UE supports RAN sharing. In particular, before establishing a PC5-RRC connection, the L2 U2N relay UE can forward cell access-related information via discovery messages.

[0354] 6) Paging

[0355] When both the U2N relay UE and the U2N remote UE are in RRC IDLE or RRC INACTIVE, the U2N relay UE monitors the paging occasions of the U2N remote UE to which it is connected. When the U2N relay UE needs to monitor the paging of the U2N remote UE, the U2N relay UE shall monitor all the POs of the U2N remote UE.

[0356] When the U2N relay UE is in RRC CONNECTED and the U2N remote UE is in RRC_IDLE or RRC_INACTIVE, there are two options for paging transfer:

[0357] - If the active DL BWP of the U2N relay UE is configured with a CORESET and a paging search space, the U2N relay UE monitors the PO of the U2N remote UE to which it is connected.

[0358] - The transfer of the paging of the U2N remote UE can be performed via a dedicated RRC message from the gNB to the U2N relay UE. The dedicated RRC message for transferring the paging of the remote UE to the relay UE in RRC_CONNECTED may contain one or more remote UE IDs (5G-S-TMSI or I-RNTI).

[0359] Deciding which of the above two options to use depends on the network implementation. If configured with a paging search space, the U2N relay UE in RRC CONNECTED can determine whether to monitor the PO for the U2N remote UE based on the PC5-RRC signaling received from the U2N remote UE.

[0360] The U2N remote UE in RRC_IDLE provides the 5G-S-TMSI and the UE-specific DRX cycle (configured by the upper layer) to the U2N relay UE to request the U2N relay UE to perform PO monitoring. The U2N remote UE in RRC_INACTIVE provides the minimum value of the two UE-specific DRX cycles (configured by the upper layer and configured by the RAN), the 5G-S-TMSI and the I-RNTI for PO monitoring. The L2 U2N relay UE can notify the gNB of the remote UE information (i.e., 5G-S-TMSI / I-RNTI) via the SidelinkUEInformationNR message for paging transfer purposes. The U2N relay UE receives the paging message to check the 5G-S-TMSI / I-RNTI and sends the relevant paging record to the remote UE accordingly.

[0361] The U2N relay UE can use unicast signaling to send paging to the U2N remote UE via PC5.

[0362] 7) Access control

[0363] The U2N remote UE performs unified access control. The U2N relay UE in RRC-CONNECTED does not perform UAC for the data of the U2N remote UE.

[0364] 8) Mobility registration update and RAN area update

[0365] When the L2 U2N remote UE is connected to the L2 U2N relay UE, it performs mobility registration update / RNAU based on the serving cell of the L2 U2N relay UE. If the serving cell changes (due to cell change of the U2N relay UE) and the new serving cell is outside the configured RNA / TA of the U2N remote UE, the L2 U2N remote UE in RRC_IDLE or RRC_INACTIVE initiates the mobility registration update / RNAU procedure.

[0366] Service Continuity for L2 U2N Relay

[0367] 1) Handover from indirect to direct path

[0368] Figure 14 The process of the U2N remote UE handing over to a direct Uu cell is illustrated.

[0369] For the service continuity of the L2 U2N relay, in the case of the U2N remote UE handing over to the direct path, the following process is used:

[0370] 1. Perform the Uu measurement configuration and measurement reporting signaling procedure to evaluate both the relay link measurement and the Uu link measurement. When the configured measurement reporting criteria are met, report the measurement results from the U2N remote UE. The sidelink relay measurement report shall include at least the source L2 ID of the U2N relay UE, the serving cell ID (i.e., NCGI), and the sidelink measurement quantity information. The sidelink measurement quantity can be the SL-RSRP of the serving U2N relay UE, and if the SL-RSRP is not available, SD-RSRP is used.

[0371] 2. The gNB decides to hand over the U2N remote UE to the direct Uu path.

[0372] 3. The gNB sends an RRCReconfiguration message to the U2N remote UE. The U2N remote UE stops the UP and CP transmissions via the U2N relay UE after receiving the RRCReconfiguration message from the gNB.

[0373] 4. The U2N remote UE synchronizes with the gNB and performs random access.

[0374] 5. The UE (i.e., the U2N remote UE in the previous step) sends RRCReconfigurationComplete to the gNB via the direct path using the configuration provided in the RRCReconfiguration message. According to this step, the UE (i.e., the U2N remote UE in the previous step) uses the RRC connection via the direct path to the gNB.

[0375] 6. The gNB sends an RRCReconfiguration message to the U2N relay UE to reconfigure the connection between the U2N relay UE and the gNB. The RRCReconfiguration message to the U2N relay UE can be sent at any time after step 3 based on the gNB implementation (e.g., to release the Uu and PC5 relay RLC channel configurations for relay, and the bearer mapping configuration between PC5 RLC and Uu RLC).

[0376] 7. The U2N relay UE or the U2N remote UE can initiate a PC5 unicast link release (PC5-S). The timing of performing the link release depends on the UE implementation. After receiving the RRC reconfiguration from the gNB in step 6, the U2N relay UE can perform a PC5 connection reconfiguration to release the PC5 relay RLC channel for relay, or after receiving the RRC reconfiguration from the gNB in step 3, the UE (i.e., the previous U2N remote UE) can perform a PC5 connection reconfiguration to release the PC5 relay RLC channel for relay.

[0377] 8. The data path is switched from the indirect path between the UE (i.e., the previous U2N remote UE) and the gNB to the direct path. The DL / UL lossless transfer during the path switch is completed according to the PDCP data recovery process.

[0378] Note: Step 8 can be performed at any time after step 4. Step 8 is independent of steps 6 and 7.

[0379] 2) Switching from direct to indirect path

[0380] Figure 15 Illustrates the process of the U2N remote UE switching to the indirect path.

[0381] The gNB can select a U2N relay UE in any RRC state (i.e., RRC_IDLE, RRC_INACTIVE, or RRC_CONNECTED) as the target U2N relay UE for the direct-to-indirect path switch.

[0382] For the service continuity of the L2 U2N remote UE, when the L2 U2N remote UE switches to an indirect path via a U2N relay UE in the RRC_CONNECTED state, the following procedure is used:

[0383] 1. After the U2N remote UE measures / finds candidate U2N relay UEs, the U2N remote UE reports one or more candidate U2N relay UEs and Uu measurements.

[0384] - The UE may filter appropriate U2N relay UEs according to relay selection criteria before reporting. The UE shall only report candidate U2N relay UEs that meet the higher layer criteria.

[0385] - The report may at least include the U2N relay UE ID, the serving cell ID of the U2N relay UE, and sidelink measurement quantity information. The sidelink measurement quantity may be the SL-RSRP of the candidate U2N relay UE, and if the SL-RSRP is not available, the SD-RSRP is used.

[0386] 2. The gNB decides to switch the U2N remote UE to the target U2N relay UE. Then, the gNB sends an RRCReconfiguration message to the target U2N relay UE, which may at least include the local ID and L2ID of the remote UE, the Uu and PC5 relay RLC channel configurations for the relay, and the bearer mapping configuration.

[0387] 3. The gNB sends an RRCReconfiguration message to the U2N remote UE. The content in the RRCReconfiguration message may at least include the U2N relay UE ID, the PC5 relay RLC channel configuration for the relay service, and the associated end-to-end radio bearer. After receiving the RRCReconfiguration message from the gNB, the U2N remote UE stops the UP and CP transmissions via the Uu.

[0388] 4. The U2N remote UE establishes a PC5 connection with the target U2N relay UE.

[0389] 5. The U2N remote UE completes the path switching process by sending an RRCReconfigurationComplete message to the gNB via the relay UE.

[0390] 6. The data path is switched from the direct path between the U2N remote UE and the gNB to the indirect path.

[0391] In the case where the selected U2N relay UE for direct-to-indirect path switching is in RRC_IDLE or RRC_INACTIVE, after receiving the path switching command, the U2N remote UE establishes a PC5 link with the U2N relay UE and sends an RRCReconfigurationComplete message via the U2N relay UE, which will trigger the U2N relay UE to enter the RRC_CONNECTED state. Figure 15 The process of the U2N remote UE switching to the indirect path in Figure 15 can also be applied to the case where the selected U2N relay UE for direct-to-indirect path switching is in RRC_IDLE or RRC_INACTIVE, except that step 4 is performed before step 2.

[0392] Sidelink Discovery

[0393] The UE can perform NR sidelink discovery when it is within or outside the coverage area for non-relay operations.

[0394] The relay discovery mechanism (except for the discovery message transmission based on the U2N relay specific threshold) is also applied to sidelink discovery.

[0395] Signaling for Path Addition between UEs

[0396] According to the prior art, when the relay UE and the remote UE are configured with the UE-to-network relay (U2N relay) function, the relay UE provides a connection to the network for the U2N remote UE. In this case, the remote UE does not have a direct connection to the network and maintains an indirect connection based on the U2N relay function.

[0397] At the same time, it is beneficial for the remote UE to support multi-path (MP) operation by only maintaining a direct connection on Uu and an indirect connection based on both PC5 and Uu. The remote UE configured with MP operation can select one or both of the connections for data transmission towards the network to achieve more reliable transmission and / or higher throughput.

[0398] For MP operation, while having a direct connection, the remote UE should be able to configure the indirect connection. Or, while having an indirect connection, the remote UE should be able to configure the direct connection. However, according to the prior art, configuring or releasing the indirect connection based on the direct connection or configuring or releasing the direct connection based on the indirect connection is not supported.

[0399] To solve this problem, the UE can perform one or more of the following operations:

[0400] - When receiving an RRC reconfiguration for adding a direct path to a remote UE that already has an indirect path, the remote UE may trigger a RACH procedure and send a MAC CE and / or an RRC reconfiguration complete message via the added direct path on the target cell indicated by the RRC reconfiguration message.

[0401] The MAC CE or the RRC reconfiguration complete message may include the UE ID of the remote UE (e.g., C-RNTI, s-TMSI, or I-RNTI).

[0402] Alternatively, the UE may trigger a RACH procedure and send a MAC CE with the UE ID of the remote UE directly to the gNB while sending an RRC reconfiguration complete message without the UE ID of the remote UE via the indirect path.

[0403] - After receiving an RRC reconfiguration for adding an indirect path of a relay UE to a remote UE that already has a direct path, the remote UE may send an RRC reconfiguration complete message on the direct path to the gNB while sending (sidelink) signaling to the relay UE under RRC_IDLE or RRC_INACTIVE.

[0404] The signaling may include the UE ID of the remote UE (e.g., C-RNTI, s-TMSI, or I-RNTI).

[0405] Upon receiving the signaling, the relay UE may initiate an RRC connection establishment or restoration procedure to the gNB and, after entering RRC_CONNECTED, for example, after the security mode command is completed between the relay UE and the gNB or after the relay UE successfully receives the first RRC reconfiguration message from the gNB, notify the gNB of the UE ID of the remote UE.

[0406] The remote UE does not send signaling to the relay UE under RRC_CONNECTED.

[0407] Alternatively, the remote UE sends an RRC reconfiguration complete message on the indirect path via the relay UE after establishing a unicast link with the relay UE.

[0408] The RRC reconfiguration complete message may include the UE ID of the remote UE (e.g., C-RNTI, s-TMSI, or I-RNTI).

[0409] Figure 16 An example of U2N bearer establishment for L2 U2N remote UE and L2 U2N relay UE is illustrated.

[0410] Refer to Figure 16, the remote UE and the relay UE perform PC5 connection establishment.

[0411] The remote UE may send an RRC reconfiguration sidelink message to the relay UE and receive an RRC reconfiguration sidelink complete message from the relay UE (1).

[0412] The remote UE sends an RRC establishment request message to the gNB and receives an RRC establishment message from the gNB (2).

[0413] The remote / relay UE and the gNB prepare the PC5 and Uu RLC channels for SRB1 (3).

[0414] The remote UE sends an RRC establishment complete message to the gNB (4).

[0415] The remote UE receives a security mode command from the gNB and sends a security mode complete to the gNB (5).

[0416] The relay UE may send sidelink UE information NR for the remote UE to the gNB (6).

[0417] The remote UE receives an RRC reconfiguration message and sends an RRC reconfiguration complete message (7).

[0418] The relay UE may perform an RRC reconfiguration procedure with the remote UE and the gNB (8A, 8).

[0419] Figure 17 An example of gNB-initiated Uu addition / modification is illustrated.

[0420] Refer to Figure 17 , the remote UE may perform U2N bearer establishment (e.g., Figure 16 ). And the gNB may send user data to the remote UE through the relay UE on the indirect path.

[0421] The relay UE may send sidelink UE information (1). The sidelink UE information may be sent to indicate that the remote UE requires multi-path. And the gNB may decide to configure multi-path for the remote UE.

[0422] The remote UE may receive RAN paging from the gNB and perform RRC connection establishment (2).

[0423] The remote UE may send sidelink UE information (3). The sidelink UE information may be sent to indicate that the remote UE requires multi-path.

[0424] The remote UE may receive an RRC reconfiguration message through the relay UE on the indirect path (5) and send an RRC reconfiguration complete message (6).

[0425] And a PDU session modification procedure (7, 8, 9) can be performed in the network.

[0426] Figure 18 Illustrates a first example of the Uu-based U2N addition procedure (Alternative 1-1).

[0427] Referring Figure 18 , the remote UE can perform RRC connection establishment (0) with the gNB.

[0428] The remote UE can perform a discovery procedure and PC5 establishment (1) with the relay UE.

[0429] The remote UE can send a measurement report (2) to the gNB. The measurement report can include a measurement report for the relay UE.

[0430] The gNB can make a multi-path decision.

[0431] The relay UE can receive RAN paging (3A) from the gNB and a request for RRC connection establishment for the relay UE (3B) from the remote UE.

[0432] The relay UE can perform RRC connection establishment (4) with the gNB.

[0433] The gNB can send an RRC reconfiguration message (5) for the two UEs to the relay UE, and the relay UE can forward the RRC reconfiguration message for the remote UE (5A) to the remote UE.

[0434] The gNB can receive RRC reconfiguration complete messages (6, 6A) from the two UEs.

[0435] And a PDU session modification procedure (7, 8, 9) can be performed in the network.

[0436] Figure 19 Illustrates a second example of the Uu-based U2N addition procedure (Alternative 1-2).

[0437] Referring Figure 19 , the remote UE can perform a discovery procedure and PC5 establishment (0) with the relay UE.

[0438] The remote UE can perform RRC connection establishment (1) with the gNB.

[0439] The remote UE can send sidelink UE information (2) to the gNB. The sidelink UE information can include information about the unicast link with the relay UE.

[0440] The gNB can make a multi-path decision.

[0441] The relay UE can receive RAN paging (3A) from the gNB and a request for RRC connection establishment for the relay UE from the remote UE (3B).

[0442] The relay UE can perform RRC connection establishment (4) with the gNB.

[0443] The gNB can send an RRC reconfiguration message for both UEs to the relay UE (5), and the relay UE can forward the RRC reconfiguration message for the remote UE to the remote UE (5A).

[0444] The gNB can receive RRC reconfiguration complete messages from both UEs (6, 6A).

[0445] And the PDU session modification procedure can be performed in the network (7, 8, 9).

[0446] Figure 20 A third example (Alternative 1-3) of the Uu-based U2N addition procedure is illustrated.

[0447] Refer to Figure 20 , the remote UE can perform RRC connection establishment (0) with the gNB.

[0448] The remote UE can perform a discovery procedure and PC5 establishment (1) with the relay UE.

[0449] The remote UE can send a request for RRC connection establishment for the relay UE to the gNB (2).

[0450] The gNB can perform RRC connection establishment (3) with the relay UE.

[0451] The gNB can receive sidelink UE information from the relay UE (4). The sidelink UE information can include information about the unicast link with the remote UE.

[0452] The gNB can make a multipath decision.

[0453] The gNB can send an RRC reconfiguration message for both UEs to the relay UE (5), and the relay UE can forward the RRC reconfiguration message for the remote UE to the remote UE (5A).

[0454] The gNB can receive RRC reconfiguration complete messages from both UEs (6, 6A).

[0455] And the PDU session modification procedure can be performed in the network (7, 8, 9).

[0456] Upon receiving an RRC reconfiguration for adding a direct path to a remote UE that already has an indirect path, the remote UE triggers a RACH to send a MAC CE and / or an RRC reconfiguration complete message on the target cell indicated by the RRC reconfiguration message as follows:

[0457] (1) Option 1: The remote UE directly sends the C-RNTI MAC CE in MSG3 / MSGA to the gNB, but sends the RRC reconfiguration complete message to the gNB indirectly via the relay UE.

[0458] - The C-RNTI is given by the RRC reconfiguration message.

[0459] - The C-RNTI MAC CE can indicate "direct path" or "indirect path" or "multi-path".

[0460] - The C-RNTI MAC CE can indicate the UE ID of the relay UE (e.g., layer-2 source or destination ID, C-RNTI or s-TMSI).

[0461] (2) Option 2: The remote UE directly sends both the RRC reconfiguration complete message and the C-RNTI MAC CE in MSG3 / MSGA to the gNB.

[0462] - The RRC reconfiguration complete message can indicate "direct path" or "indirect path" or "multi-path".

[0463] - The RRC reconfiguration complete message can indicate the UE ID of the relay UE (e.g., layer-2 source or destination ID, C-RNTI or s-TMSI).

[0464] (3) Option 3: The remote UE sends an RRC reconfiguration complete message with the remote UE ID (C-RNTI or s-TMSI) in MSG3 / MSGA.

[0465] - The RRC reconfiguration complete message can indicate "direct path" or "indirect path" or "multi-path".

[0466] - The RRC reconfiguration complete message can indicate the UE ID of the relay UE (e.g., layer-2 source or destination ID, C-RNTI or s-TMSI).

[0467] Upon detecting a RACH failure or expiration of the reconfiguration timer, the remote UE performs one of the following alternatives:

[0468] (1) Alternative 1: The remote UE triggers an RRC reconstruction procedure (e.g., directly or indirectly).

[0469] (2) Alternative 2: The remote UE notifies the gNB of the failure of the RRC reconfiguration by, for example, indirectly sending MCG or SCG or SL failure information to the gNB via a relay UE.

[0470] Upon receiving an RRC reconfiguration for adding an indirect path to a remote UE that already has a direct path, the remote UE sends an RRC reconfiguration complete message as follows:

[0471] If the remote UE does not have a unicast link with the target relay UE indicated by the RRC reconfiguration message,

[0472] - The remote UE triggers the establishment of a PC5 unicast link with the target relay UE

[0473] - If the remote UE successfully establishes a PC5 unicast link with the target relay UE,

[0474] (i) Alternative 1: The remote UE directly sends an RRC reconfiguration complete message to the gNB after successfully sending SL signaling (e.g., upon receiving an SL RLC ACK or an SL HARQ ACK).

[0475] If the RRC state of the relay UE has been notified to the remote UE (e.g., via a discovery signal or PC5-S signaling or a PC5-RRC message from the relay UE), then

[0476] If the relay UE is not in RRC_CONNECTED, before sending an RRC reconfiguration complete message to the gNB, the remote UE notifies the target relay UE of the establishment of the indirect path via SL signaling (using the RRC connection establishment of the relay UE).

[0477] The SL signaling can be one of a discovery message, sidelink control information, an SL MAC control element, a PC5-RRC message, and PC5-S signaling.

[0478] If the relay UE is in RRC_CONNECTED, the remote UE does not send SL signaling to the relay UE.

[0479] If an SL failure is detected on the PC5 unicast link before sending an RRC reconfiguration complete message to the gNB, the remote UE does not send an RRC reconfiguration complete message to the gNB and performs one of the following alternatives:

[0480] 1) Alternative 1: The remote UE triggers an RRC reconstruction procedure (e.g., directly or indirectly).

[0481] 2) Alternative 2: The remote UE notifies the gNB of the failure of the RRC reconfiguration by, for example, directly sending MCG or SCG or SL failure information to the gNB.

[0482] (ii) Alternative 2: The remote UE indirectly sends an RRC reconfiguration complete message with the remote UE ID (C-RNTI or s-TMSI) to the gNB via the relay UE.

[0483] If the relay UE is in RRC_IDLE or RRC_INACTIVE, when receiving SL signaling, or when receiving the RRC reconfiguration complete message, or when receiving a PDU on the PC5 relay RLC channel for SRB1 (i.e., SL-RLC1), the relay UE sends an RRC establishment request or an RRC resume request to enter RRC_CONNECTED.

[0484] The RRC establishment request or the RRC resume request may indicate one or more of the following:

[0485] - Establishment of, for example, "multi-path" or "indirect path" as the establishment cause.

[0486] - The UE ID of the remote UE (e.g., layer-2 source or destination ID, C-RNTI or s-TMSI).

[0487] - The UE ID of the relay UE (e.g., layer-2 source or destination ID, C-RNTI or s-TMSI).

[0488] If the relay UE fails to enter RRC_CONNECTED, the relay UE notifies the remote UE of the failure of the indirect path.

[0489] When receiving the failure of the indirect path, the remote UE performs the following alternative:

[0490] 1) Alternative 1: The remote UE triggers an RRC reconstruction process (e.g., the remote UE performs RACH).

[0491] 2) Alternative 2: The remote UE notifies the gNB of the failure of the RRC reconfiguration, for example, by directly sending MCG or SCG or SL failure information to the gNB.

[0492] If the relay UE is in RRC_CONNECTED, the relay UE performs the following operations:

[0493] When the RRC reconfiguration message from the gNB configures an indirect path for the remote UE,

[0494] - If SL signaling has been received from the remote UE, the relay UE applies the RRC reconfiguration message and sends an RRC reconfiguration complete message to the gNB.

[0495] - If the SL signaling has not been received from the remote UE, the relay UE does not apply the RRC reconfiguration message, considers the RRC reconfiguration not to be successfully completed, and triggers an RRC reconstruction procedure or notifies the gNB of the failure of the RRC reconfiguration, for example, by sending MCG or SCG or SL failure information to the gNB.

[0496] Alternatively, upon receiving the SL signaling, the relay UE ignores the SL signaling.

[0497] - If the remote UE fails to establish a unicast link with the target relay UE, the remote UE performs the following alternative:

[0498] (i) Alternative 1: The remote UE triggers an RRC reconstruction procedure (e.g., the remote UE performs RACH).

[0499] (ii) Alternative 2: The remote UE notifies the gNB of the failure of the RRC reconfiguration, for example, by directly sending MCG or SCG or SL failure information to the gNB.

[0500] This embodiment can be used in Scenario 1 or Scenario 2.

[0501] For multi-path relay scenario - 1, the relay UE and the remote UE are connected by a 3GPP side link.

[0502] For multi-path relay scenario 2, the relay UE and the remote UE are connected by a non-3GPP link (e.g., an ideal link or WiFi) and can be semi-statically associated.

[0503] - In Scenario 2, a bearer identifier other than the LCID is not required in the L2 PDU on the Uu link. For the indirect path, only 1:1 bearer mapping is supported on the Uu link. FFS how to configure the mapping.

[0504] - In the case of no adaptation layer on the Uu link in Scenario 2, the PDCP PDU can be delivered to the intended PDCP entity or RLC entity to support more than one RB on the Uu link (e.g., by configuring 1:1 bearer mapping and different Uu RLC channels for the relay UE's local traffic and the relay traffic for PDU delivery).

[0505] - Ensure a 1:1 mapping between one receive / transmit PDCP entity of the remote UE and one LCID value of the DL / UL MAC PDU from the relay UE through the configuration of the gNB.

[0506] For multi-path relay scenario - 2, RAN2 assumes that the CN is not aware of the semi-static relationship between the remote UE and the relay UE.

[0507] For multi-path relay scenario - 2, the UE notifies the gNB of the semi-static relationship between the remote UE and the relay UE by using the C-RNTI according to one of the following options:

[0508] (1) Option 1: After entering RRC_CONNECTED, the relay UE notifies the gNB of the C-RNTI of the remote UE while both UEs are in RRC_CONNECTED. Additionally, the relay UE may notify the remote UE that the relay UE has notified the gNB of the C-RNTI of the remote UE.

[0509] (2) Option 2: After the relay UE enters RRC_CONNECTED, the relay UE notifies the remote UE of the relay UE's C-RNTI. Then, the remote UE notifies the gNB of the relay UE's C-RNTI.

[0510] (3) Option 3: When the relay UE enters RRC_CONNECTED, the relay UE sends an initial UE NAS message to the AMF. Based on the semi-static relationship between the remote UE and the relay UE, the initial UE NAS message includes the UE ID of the remote UE and the UE ID of the relay UE. For this operation, the remote UE may notify the relay UE of the remote UE's UE ID (e.g., s-TMSI). Then, the AMF notifies the gNB of the semi-static relationship between the remote UE and the relay UE based on the UE IDs of the two UEs.

[0511] Figure 21 An example shows the remote UE sending remote UE information to the relay UE.

[0512] The remote UE information transmission process is used by the L2 U2N remote UE in RRC_IDLE / RRC_INACTIVE to notify the required SIBs and provide paging-related information to the connected L2 U2N relay UE. The L2 U2N remote UE does not require the MIB.

[0513] Actions Related to the Transmission of RemoteUEInformationSidelink Message

[0514] When entering RRC_IDLE or RRC_INACTIVE, or when any information in RemoteUEInformationSidelink changes while in RRC_IDLE or RRC_INACTIVE, the L2 U2N remote UE shall:

[0515] 1> If the UE has not previously stored a valid version of the SIBs of one or more required SIBs and the requested SIBs have not been indicated in the RemoteUEInformationSidelink message to the L2 U2N relay UE, then:

[0516] 2> Include sl-RequestedSIB-List in RemoteUEInformationSidelink to indicate the requested SIB;

[0517] 1> If the UE has not previously sent sl-PagingInfo-RemoteUE in the RemoteUEInformationSidelink message to the L2 U2N relay UE, set sl-PagingInfo-RemoteUE as follows:

[0518] 2> If the L2 U2N remote UE is in RRC_IDLE, then:

[0519] 3> Include ng-5G-S-TMSI in sl-PagingIdentityRemoteUE;

[0520] 3> If the UE-specific DRX cycle is configured by the upper layer, set sl-PagingCycleRemoteUE to the value of the UE-specific Uu DRX cycle configured by the upper layer;

[0521] 2> Otherwise, if the L2 U2N remote UE is in RRC_INACTIVE:

[0522] 3> Include ng-5G-S-TMSI and fullI-RNTI in sl-PagingIdentityRemoteUE;

[0523] 3> If the UE-specific DRX cycle is configured by the upper layer,

[0524] 4> Set sl-PagingCycleRemoteUE to the minimum value of the UE-specific Uu DRX cycle (configured by the upper layer and configured by RRC);

[0525] 3> Otherwise:

[0526] 4> Set sl-PagingCycleRemoteUE to the value of the UE-specific DRX cycle configured by RRC;

[0527] 1> Submit the RemoteUEInformationSidelink message to the lower layer for transmission;

[0528] When entering RRC_CONNECTED, if the L2 U2N remote UE without multi-path operation configured has sent sl-RequestedSIB-List and / or sl-PagingInfo-RemoteUE; or

[0529] If the RRCReconfiguration message includes a pagingSearchSpace, if the L2 U2N remote UE is configured with an active BWP of the pagingSearchSpace at the cell on the direct path of the multipath operation, and if the L2 U2N remote UE has sent an sl-RequestedSIB-List and / or sl-PagingInfo-RemoteUE to the U2N relay UE on the indirect path, then when the RRCReconfiguration message includes a configuration for multipath operation (e.g., when adding a direct path to a U2N remote UE having an indirect path via a U2N relay UE, or when adding an indirect path of a U2N relay UE to a U2N remote UE having a direct path); or

[0530] If the RRCReconfiguration message includes a searchSpaceSIB1 and / or a searchSpaceOtherSystemInformation, if the L2 U2N remote UE is configured with an active BWP of the searchSpaceSIB1 and / or the searchSpaceOtherSystemInformation at the cell on the direct path of the multipath operation, and if the L2 U2N remote UE has sent an sl-RequestedSIB-List and / or sl-PagingInfo-RemoteUE to the U2N relay UE on the indirect path, then when the RRCReconfiguration message includes a configuration for multipath operation (e.g., when adding a direct path to a U2N remote UE having an indirect path via a U2N relay UE, or when adding an indirect path of a U2N relay UE to a U2N remote UE having a direct path); or

[0531] If multipath operation has been configured, and if the L2 U2N remote UE switches from a BWP that does not have a pagingSearchSpace to a BWP that is configured with a pagingSearchSpace at the cell on the direct path of the multipath operation; or

[0532] If multipath operation has been configured, and if the L2 U2N remote UE switches from a BWP that does not have a searchSpaceSIB1 and / or a searchSpaceOtherSystemInformation to a BWP that is configured with a searchSpaceSIB1 and / or a searchSpaceOtherSystemInformation at the cell on the direct path of the multipath operation, then:

[0533] The L2 U2N remote UE shall:

[0534] 1> Set the sl-RequestedSIB-List to the value Release if it has been requested before;

[0535] 1> Set the sl-PagingInfo-RemoteUE to the value Release if it has been sent before;

[0536] 1> Submit the RemoteUEInformationSidelink message to the lower layer for transmission;

[0537] If the RemoteUEInformationSidelink message has been successfully sent (e.g., upon receiving a HARQ ACK or an RLC ACK for sending the RemoteUEInformationSidelink message), then:

[0538] 1> If the UuMessageTransferSidelink message received from the relay UE includes a paging message containing the ue-Identity of the L2 U2N remote UE:

[0539] 2> (Alternative 1) The remote UE discards the paging message (because the remote UE receives paging directly from the gNB or is in RRC_CONNECTED).

[0540] 2> (Alternative 2) The remote UE triggers a RACH on the cell of the direct path as follows (when the gNB pages the remote UE on the indirect path via the relay UE to trigger a RACH on the (added) direct path):

[0541] [Table 6]

[0542]

[0543] 1> If the UuMessageTransferSidelink message received from the relay UE includes sl-SIB1-Delivery: 2> (Alternative 1), if any condition for initiating the Uu message transfer procedure related to SIB1 is met, the remote UE updates SIB1 according to sl-SIB1-Delivery (i.e., overwrites any SIB1 that the remote UE has received directly from the gNB). Otherwise, the remote UE discards sl-SIB1-Delivery.

[0544] 2> (Alternative 2) The remote UE always discards sl-SIB1-Delivery regardless of whether any condition for initiating the Uu message transfer procedure related to SIB1 is met.

[0545] 1> If the UuMessageTransferSidelink message received from the relay UE includes sl-SystemInformationDelivery:

[0546] 2> (Alternative 1) If any condition for initiating the Uu message transfer procedure related to system information is satisfied, the remote UE updates the SIB according to sl-SystemInformationDelivery (i.e., if sl-SystemInformationDelivery includes an SIB type, it overwrites any SIB type that the remote UE has received directly from the gNB). Otherwise, the remote UE discards sl-SystemInformationDelivery.

[0547] 2> (Alternative 2) The remote UE always discards sl-SystemInformationDelivery, regardless of whether any condition for initiating the Uu message transfer procedure related to system information is satisfied.

[0548] 1> If the UuMessageTransferSidelink message received from the relay UE includes the short message in Table x,

[0549] 2> If the remote UE is on an active BWP that does not have a common search space for SIB1 and / or other SI, or if the common search space for SIB1 and / or other SI is not configured, the remote UE discards the short message.

[0550] 2> If the common search space for SIB1 and / or system information (for other SIBs) is configured, the remote UE receives SIB1 and / or the updated SIB from the cell on the direct path as follows:

[0551] [Table 7]

[0552]

[0553] [Table 8]

[0554]

[0555]

[0556] If an RRCReconfiguration message including a configuration for multipath operation is received (e.g., when adding a direct path to a U2N remote UE having an indirect path via a U2N relay UE or when adding an indirect path of a U2N relay UE to a U2N remote UE having a direct path), the L2 U2N remote UE in RRC_CONNECTED shall:

[0557] 1> If the pagingSearchSpace is not configured after receiving the RRCReconfiguration message and if the UE has not previously sent the sl-RequestedSIB-List and / or sl-PagingInfo-RemoteUE in the RemoteUEInformationSidelink message to the L2 U2N relay UE; or

[0558] 1> If the searchSpaceSIB1 and / or searchSpaceOtherSystemInformation are not configured after receiving the RRCReconfiguration message and if the UE has not previously sent the sl-RequestedSIB-List and / or sl-PagingInfo-RemoteUE in the RemoteUEInformationSidelink message to the L2 U2N relay UE; or

[0559] 1> If the L2 U2N remote UE has sent the sl-RequestedSIB-List and / or sl-PagingInfo-RemoteUE to the U2N relay UE of the indirect path and if the sl-RequestedSIB-List and / or sl-PagingInfo-RemoteUE need to be updated; or

[0560] 1> If the L2 U2N remote UE switches from a BWP having a pagingSearchSpace to a BWP without a pagingSearchSpace at a cell of the direct path for multipath operation; or

[0561] 1> If the L2 U2N remote UE switches from a BWP having the searchSpaceSIB1 and / or searchSpaceOtherSystemInformation to a BWP without the searchSpaceSIB1 and / or searchSpaceOtherSystemInformation configured at a cell of the direct path for multipath operation, then:

[0562] 2> Set the sl-RequestedSIB-List to any requested SIB in the RemoteUEInformationSidelink message;

[0563] 2> Set the sl-PagingInfo-RemoteUE in the RemoteUEInformationSidelink message as follows:

[0564] 3> (Alternative 1) Include the ng-5G-S-TMSI and C-RNTI in the sl-PagingIdentityRemoteUE;

[0565] 3> (Alternative 2) Indicate "empty" or "none" or a specific value or any value in the sl-PagingIdentityRemoteUE; (used to avoid including any UE ID)

[0566] 3> (Alternative 3) Do not include the sl-PagingIdentityRemoteUE in the RemoteUEInformationSidelink;

[0567] 3> If the UE-specific DRX cycle is configured by the upper layer or RRC, then

[0568] 4> Set the sl-PagingCycleRemoteUE to the minimum value of the UE-specific Uu DRX cycle (configured by the upper layer and configured by RRC) or the value of the UE-specific DRX cycle configured by RRC;

[0569] 2> Submit the RemoteUEInformationSidelink message to the lower layer for transmission;

[0570] L2 U2N Relay UE Receives RemoteUEInformationSidelink Message

[0571] The L2 U2N relay UE shall:

[0572] 1> If the RemoteUEInformationSidelink includes the sl-PagingInfo-RemoteUE, then:

[0573] 2> If the UE is in RRC_CONNECTED on the active BWP that is configured to include the pagingSearchSpace in the common search space; or

[0574] 2> If the UE is in RRC_IDLE or RRC_INACTIVE:

[0575] 3> If sl-PagingInfo-RemoteUE is set to establish:

[0576] 4> Monitor for paging messages at the paging occasion of the L2 U2N remote UE calculated according to the sl-PagingIdentityRemoteUE and sl-PagingCycleRemoteUE included in sl-PagingInfo-RemoteUE;

[0577] [Table 9]

[0578]

[0579]

[0580] 3> Otherwise (sl-PagingInfo-RemoteUE is set to release): 4> Stop monitoring for paging messages at the paging occasion of the L2 U2N remote UE;

[0581] 4> Release the received paging information in sl-PagingInfo-RemoteUE;

[0582] 2> Otherwise (the UE is in RRC_CONNECTED on an active BWP without a configured pagingSearchSpace):

[0583] 3> If sl-PagingInfo-RemoteUE is set to establish:

[0584] 4> Include the received sl-PagingIdentityRemoteUE in the SidelinkUEInformationNR message and perform sidelink UE information transmission according to Table 10;

[0585] 3> Otherwise (sl-PagingInfo-RemoteUE is set to release):

[0586] 4> Initiate the transmission of the SidelinkUEInformationNR message according to Table 10 to release the sl-PagingIdentityRemoteUE in the SidelinkUEInformationNR message;

[0587] [Table 10]

[0588]

[0589] 4> Release the received paging information in sl-PagingInfo-RemoteUE; 1> If sl-RequestedSIB-List is included in RemoteUEInformationSidelink, then:

[0590] 2> If sl-RequestedSIB-List is set to establish, then:

[0591] 3> If the L2 U2N relay UE has not stored a valid version of the SIB indicated in sl-RequestedSIB-List, then:

[0592] 4> Perform the acquisition of the system information indicated in sl-RequestedSIB-List;

[0593] 3> Otherwise:

[0594] 4> Perform the Uu message transfer procedure;

[0595] 2> If sl-RequestedSIB-List is set to release:

[0596] 3> Release the received SIB request in sl-RequestedSIB-List.

[0597] Using the disclosed embodiments, the network can configure direct paths and indirect paths for multipath operation for relay UEs and remote UEs according to the present invention, especially when UEs can exchange signaling.

[0598] The disclosed embodiments are beneficial because the system can appropriately provide the configuration of additional paths (i.e., indirect links or direct links via U2N relays for multipath operation). In the prior art, there is no mechanism to configure additional paths for multipath operation with relay UEs.

[0599] Figure 22 Illustrates a method performed by a first user equipment (UE) in one embodiment of the present disclosure. The first UE may operate in a wireless communication system supporting one or more radio access technologies (RATs) including a first RAT.

[0600] Refer to Figure 22 , the first UE may receive information (A05) about the second UE from the second UE via a second RAT connection between the first UE and the second UE.

[0601] The first UE may send a first RAT-based signal (A10) including the information about the second UE received via the second RAT connection to a base station (BS).

[0602] The first UE may receive, from the BS, configuration information (A15) for an indirect path between the first UE and the BS via a second UE.

[0603] Information about the second UE received via a second RAT connection may include a UE identifier of the second UE assigned by the BS based on a first RAT.

[0604] Preferably, the UE identifier of the second UE may be a cell-radio network temporary identifier (C-RNTI) of the second UE.

[0605] Preferably, the C-RNTI of the second UE is sent to the BS to report to the BS that the second UE may be in a radio resource control (RRC) connected state based on the first RAT.

[0606] Preferably, the second UE may be a candidate for a relay UE configured for an indirect path.

[0607] Preferably, the configuration information for the indirect path may include information about a relay UE.

[0608] Preferably, the relay UE may be determined based on a signal based on the first RAT sent by the first UE.

[0609] Preferably, the first UE may be a remote UE configured with a direct path to the BS. The direct path may be configured by performing a random access procedure with the BS.

[0610] Preferably, the indirect path may include a first RAT connection between the second UE and the BS and a second RAT connection between the first UE and the second UE.

[0611] Preferably, the first RAT may be a 3rd Generation Partnership Project 3GPP RAT, and the second RAT may be a non-3GPP RAT.

[0612] Preferably, the second RAT connection may be different from a 3GPP side link connection.

[0613] Figure 23 An example of a method performed by a base station (BS) in one embodiment of the present disclosure is illustrated. The BS may operate in a wireless communication system supporting one or more radio access technologies (RATs) including a first RAT.

[0614] Referring to Figure 23 , the BS may receive, from a first user equipment (UE), a signal based on a second RAT (B05) including information about one or more UEs.

[0615] The BS may determine configuration information (B10) for an indirect path between the first UE and the BS.

[0616] The BS may send configuration information (B15) for an indirect path to the first UE.

[0617] The information about one or more UEs may include information about a second UE having a second RAT connection with the first UE.

[0618] The information about the second UE may include a UE identifier of the second UE assigned by the BS based on the first RAT.

[0619] Preferably, the UE identifier of the second UE may be a cell-radio network temporary identifier (C-RNTI) of the second UE.

[0620] Preferably, the BS may determine that the second UE is in a radio resource control (RRC) connected state based on the first RAT based on receipt of the C-RNTI of the second UE.

[0621] Preferably, the second UE may be a candidate for a relay UE configured for an indirect path.

[0622] Preferably, the configuration information for the indirect path may include information about the relay UE.

[0623] Preferably, the relay UE may be determined based on a signal based on the first RAT sent by the first UE.

[0624] Preferably, the first UE may be a remote UE configured with a direct path to the BS. The direct path may be configured based on a random access procedure between the first UE and the BS.

[0625] Preferably, the indirect path may include a first RAT connection between the second UE and the BS and a second RAT connection between the first UE and the second UE.

[0626] Preferably, the first RAT may be a 3rd Generation Partnership Project 3GPP RAT, and the second RAT may be a non-3GPP RAT.

[0627] Preferably, the second RAT connection may be different from a 3GPP side link connection.

[0628] Although not limited thereto, the various descriptions, functions, processes, proposals, methods, and / or operation flowcharts of the present disclosure described herein may be applied to various fields requiring wireless communication / connection (e.g., 5G) between devices.

[0629] Hereinafter, a description will be given in more detail with reference to the drawings. In the following drawings / description, unless otherwise described, the same reference numerals may denote the same or corresponding hardware blocks, software blocks, or functional blocks.

[0630] Figure 24 illustrates a communication system to which the present disclosure is applied.

[0631] Referring to Figure 24 , the communication system 1 to which the present disclosure is applied includes a wireless device, a BS, and a network. Herein, the wireless device represents a device that performs communication using a RAT (e.g., 5G NR or LTE), and may be referred to as a communication / radio / 5G device. The wireless device may include, but is not limited to, a robot 100a, vehicles 100b-1 and 100b-2, an extended reality (XR) device 100c, a handheld device 100d, a household appliance 100e, an Internet of Things (IoT) device 100f, and an artificial intelligence (AI) device / server 400. For example, the vehicle may include a vehicle having a wireless communication function, an autonomous driving vehicle, and a vehicle capable of performing vehicle-to-vehicle communication. Herein, the vehicle may include an unmanned aerial vehicle (UAV) (e.g., a drone). The XR device may include an augmented reality (AR) / virtual reality (VR) / mixed reality (MR) device and may be implemented in the form of a head-mounted device (HMD), a head-up display (HUD) mounted in a vehicle, a TV, a smart phone, a computer, a wearable device, a household appliance device, a digital sign, a vehicle, a robot, etc. The handheld device may include a smart phone, a smart board, a wearable device (e.g., a smart watch or smart glasses), and a computer (e.g., a notebook). The household appliance may include a TV, a refrigerator, and a washing machine. The IoT device may include sensors and smart meters. For example, the BS and the network may be implemented as wireless devices, and a specific wireless device 200a may operate as a BS / network node with respect to other wireless devices.

[0632] The wireless devices 100a to 100f may be connected to the network 300 via the BS 200. AI technology may be applied to the wireless devices 100a to 100f, and the wireless devices 100a to 100f may be connected to the AI server 400 via the network 300. The network 300 may be configured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g., NR) network. Although the wireless devices 100a to 100f may communicate with each other via the BS 200 / network 300, the wireless devices 100a to 100f may perform direct communication (e.g., sidelink communication) with each other without going through the BS / network. For example, vehicles 100b-1 and 100b-2 may perform direct communication (e.g., V2V / V2X communication). The IoT device (e.g., a sensor) may perform direct communication with other IoT devices (e.g., sensors) or other wireless devices 100a to 100f.

[0633] Wireless communication / connections 150a, 150b, or 150c can be established between wireless devices 100a to 100f / BS200 or BS200 / BS200. Herein, the wireless communication / connections can be established through various RATs (e.g., 5G NR) such as UL / DL communication 150a, sidelink communication 150b (or D2D communication), or inter-BS communication (e.g., relay, integrated access backhaul (IAB)). The wireless devices and the BS / wireless devices can transmit / receive radio signals to / from each other through the wireless communication / connections 150a and 150b. For example, the wireless communication / connections 150a and 150b can transmit / receive signals through various physical channels. To this end, based on various proposals of the present disclosure, at least a part of various configuration information configuration processes, various signal processing processes (e.g., channel encoding / decoding, modulation / demodulation, and resource mapping / demapping), and resource allocation processes for transmitting / receiving radio signals can be performed.

[0634] Figure 25 Illustrates a wireless device applicable to the present disclosure.

[0635] Refer to Figure 25 , the first wireless device 100 and the second wireless device 200 can transmit radio signals through various RATs (e.g., LTE and NR). Herein, {the first wireless device 100 and the second wireless device 200} can correspond to Figure 24 {wireless device 100x and BS200} and / or {wireless device 100x and wireless device 100x} in

[0636] The first wireless device 100 may include one or more processors 102 and one or more memories 104, and may further include one or more transceivers 106 and / or one or more antennas (antenna units) 108. The processor 102 may control the memory 104 and / or the transceiver 106, and may be configured to implement the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed herein. For example, the processor 102 may process the information in the memory 104 to generate first information / signals, and then transmit radio signals including the first information / signals through the transceiver 106. The processor 102 may receive radio signals including second information / signals through the transceiver 106, and then store the information obtained by processing the second information / signals in the memory 104. The memory 104 may be connected to the processor 102 and may store various information related to the operation of the processor 102. For example, the memory 104 may store software code, which includes commands for performing part or all of the processes controlled by the processor 102 or for performing the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed herein. Herein, the processor 102 and the memory 104 may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). The transceiver 106 may be connected to the processor 102 and transmit and / or receive radio signals through one or more antennas 108. Each of the transceivers 106 may include a transmitter and / or a receiver. The transceiver 106 may be used interchangeably with the (one or more) radio frequency (RF) units. In the present disclosure, the wireless device may represent a communication modem / circuit / chip.

[0637] Specifically, the UE may include a processor 102 connected to an RF transceiver and a memory 104. The memory 104 may include at least one program for performing operations related to the embodiments described above Figures 11 to 27 in reference.

[0638] Alternatively, a chipset including a processor 102 and a memory 104 may be configured. The chipset may include: at least one processor; and at least one memory, the at least one memory being operatively connected to the at least one processor and configured to cause the at least one processor to perform operations when executed.

[0639] The second wireless device 200 may include one or more processors 202 and one or more memories 204, and may additionally include one or more transceivers 206 and / or one or more antennas 208. The processor 202 may control the memory 204 and / or the transceiver 206, and may be configured to implement the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed herein. For example, the processor 202 may process the information within the memory 204 to generate third information / signals, and then transmit radio signals including the third information / signals through the transceiver 206. The processor 202 may receive radio signals including fourth information / signals through the transceiver 106, and then store the information obtained by processing the fourth information / signals in the memory 204. The memory 204 may be connected to the processor 202 and may store various information related to the operation of the processor 202. For example, the memory 204 may store software code, which includes commands for performing part or all of the processing controlled by the processor 202 or for performing the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed herein. Herein, the processor 202 and the memory 204 may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). The transceiver 206 may be connected to the processor 202 and transmit and / or receive radio signals through one or more antennas 208. Each of the transceivers 206 may include a transmitter and / or a receiver. The transceiver 206 may be used interchangeably with the RF unit. In the present disclosure, the wireless device may represent a communication modem / circuit / chip.

[0640] In the following, the hardware components of wireless devices 100 and 200 will be described in more detail. One or more protocol layers can be implemented by one or more processors 102 and 202, without limitation. For example, one or more processors 102 and 202 can implement one or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP, RRC, and SDAP). One or more processors 102 and 202 can generate one or more protocol data units (PDUs) and / or one or more service data units (SDUs) according to the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed herein. One or more processors 102 and 202 can generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed herein. One or more processors 102 and 202 can generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed herein, and provide the generated signals to one or more transceivers 106 and 206. One or more processors 102 and 202 can receive signals (e.g., baseband signals) from one or more transceivers 106 and 206 and obtain PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed herein.

[0641] One or more processors 102 and 202 can be referred to as a controller, microcontroller, microprocessor, or microcomputer. One or more processors 102 and 202 can be implemented by hardware, firmware, software, or a combination thereof. As an example, one or more application specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processor devices (DSPDs), one or more programmable logic devices (PLDs), or one or more field programmable gate arrays (FPGAs) can be included in one or more processors 102 and 202. The descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed herein can be implemented using firmware or software, and the firmware or software can be configured to include modules, procedures, or functions. The firmware or software configured to execute the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed herein can be included in one or more processors 102 and 202 or stored in one or more memories 104 and 204 to be driven by one or more processors 102 and 202. The descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed herein can be implemented using firmware or software in the form of code, commands, and / or command sets.

[0642] One or more memories 104 and 204 may be connected to one or more processors 102 and 202, and store various types of data, signals, messages, information, programs, code, instructions, and / or commands. One or more memories 104 and 204 may be constituted by read-only memory (ROM), random access memory (RAM), electrically erasable programmable read-only memory (EPROM), flash memory, hard disk drive, register, cache memory, computer-readable storage medium, and / or a combination thereof. One or more memories 104 and 204 may be located inside and / or outside one or more processors 102 and 202. One or more memories 104 and 204 may be connected to one or more processors 102 and 202 through respective technologies such as wired or wireless connections.

[0643] One or more transceivers 106 and 206 may transmit user data, control information, and / or radio signals / channels mentioned in the methods and / or operational flowcharts herein to one or more other devices. One or more transceivers 106 and 206 may receive user data, control information, and / or radio signals / channels mentioned in the descriptions, functions, processes, proposals, methods, and / or operational flowcharts disclosed herein from one or more other devices. For example, one or more transceivers 106 and 206 may be connected to one or more processors 102 and 202 and transmit and receive radio signals. For example, one or more processors 102 and 202 may perform control such that one or more transceivers 106 and 206 may transmit user data, control information, or radio signals to one or more other devices. One or more processors 102 and 202 may perform control such that one or more transceivers 106 and 206 may receive user data, control information, or radio signals from one or more other devices. One or more transceivers 106 and 206 may be connected to one or more antennas 108 and 208, and one or more transceivers 106 and 206 may be configured to transmit and receive user data, control information, and / or radio signals / channels mentioned in the descriptions, functions, processes, proposals, methods, and / or operational flowcharts disclosed herein via one or more antennas 108 and 208. In this document, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers 106 and 206 may transform received radio signals / channels, etc. from RF band signals into baseband signals in order to process received user data, control information, radio signals / channels, etc. using one or more processors 102 and 202. One or more transceivers 106 and 206 may transform user data, control information, radio signals / channels, etc. processed using one or more processors 102 and 202 from baseband signals into RF band signals. To this end, one or more transceivers 106 and 206 may include (analog) oscillators and / or filters.

[0644] Figure 26 Another example applied to the wireless devices of the present disclosure is illustrated. The wireless devices may be implemented in various forms according to use cases / services (refer to Figure 24 ).

[0645] Refer to Figure 26 , the wireless devices 100 and 200 may correspond to Figure 25Wireless devices 100 and 200, and can be composed of various components, parts, units / sections, and / or modules. For example, each of the wireless devices 100 and 200 may include a communication unit 110, a control unit 120, a memory unit 130, and additional components 140. The communication unit may include a communication circuit 112 and one or more transceivers 114. For example, the communication circuit 112 may include Figure 25 one or more processors 102 and 202 and / or one or more memories 104 and 204. For example, the transceiver 114 may include Figure 25 one or more transceivers 106 and 206 and / or one or more antennas 108 and 208. The control unit 120 is electrically connected to the communication unit 110, the memory 130, and the additional components 140, and controls the overall operation of the wireless device. For example, the control unit 120 may control the electrical / mechanical operations of the wireless device based on programs / codes / commands / information stored in the memory unit 130. The control unit 120 may send the information stored in the memory unit 130 to the outside (e.g., other communication devices) via the communication unit 110 through a wireless / wired interface, or store the information received from the outside (e.g., other communication devices) via the communication unit 110 through a wireless / wired interface in the memory unit 130.

[0646] The additional components 140 can be configured in various ways according to the type of the wireless device. For example, the additional components 140 may include at least one of a power unit / battery, an input / output (I / O) unit, a drive unit, and a computing unit. The wireless device can be implemented in the following forms without limitation: a robot ( Figure 24 100a), a vehicle ( Figure 24 100b-1 and 100b-2), an XR device ( Figure 24 100c), a handheld device ( Figure 24 100d), a household appliance ( Figure 24 100e), an IoT device ( Figure 24 100f), a digital broadcast terminal, a holographic device, a public safety device, an MTC device, a medical device, a FinTech device (or financial device), a security device, a climate / environment device, an AI server / device ( Figure 24 400), a BS ( Figure 24 200), a network node, etc. According to use cases / services, the wireless device can be used in a mobile or fixed location.

[0647] In Figure 26Among them, various components, parts, units / sections, and / or modules in the wireless devices 100 and 200 can all be connected to each other through wired interfaces, or at least a part of them can be wirelessly connected through the communication unit 110. For example, in each of the wireless devices 100 and 200, the control unit 120 and the communication unit 110 can be connected by wire, and the control unit 120 and the first units (e.g., 130 and 140) can be wirelessly connected through the communication unit 110. Each component, part, unit / section, and / or module within the wireless devices 100 and 200 can also include one or more elements. For example, the control unit 120 can be composed of a set of one or more processors. As an example, the control unit 120 can be composed of a set of a communication control processor, an application processor, an electronic control unit (ECU), a graphics processing unit, and a memory control processor. As another example, the memory 130 can be composed of RAM, DRAM, ROM, flash memory, volatile memory, non-volatile memory, and / or a combination thereof.

[0648] Figure 27 Illustrates a vehicle or an autonomous driving vehicle to which the present disclosure is applied. The vehicle or the autonomous driving vehicle can be implemented by a mobile robot, an automobile, a train, a manned / unmanned aerial vehicle (AV), a ship, etc.

[0649] Referring to Figure 27 , the vehicle or the autonomous driving vehicle 100 can include an antenna unit 108, a communication unit 110, a control unit 120, a driving unit 140a, a power supply unit 140b, a sensor unit 140c, and an autonomous driving unit 140d. The antenna unit 108 can be configured as a part of the communication unit 110. Blocks 110 / 130 / 140a to 140d respectively correspond to Figure 26 blocks 110 / 130 / 140 of

[0650] The communication unit 110 can transmit signals (e.g., data and control signals) to external devices such as other vehicles, BSs (e.g., gNBs and roadside units), and servers, and receive the signals from the external devices. The control unit 120 can perform various operations by controlling elements of the vehicle or autonomous driving vehicle 100. The control unit 120 can include an ECU. The driving unit 140a can cause the vehicle or autonomous driving vehicle 100 to travel on a road. The driving unit 140a can include an engine, a motor, a powertrain, wheels, brakes, a steering device, etc. The power supply unit 140b can supply power to the vehicle or autonomous driving vehicle 100 and includes a wired / wireless charging circuit, a battery, etc. The sensor unit 140c can acquire vehicle state, surrounding environment information, user information, etc. The sensor unit 140c can include an inertial measurement unit (IMU) sensor, a collision sensor, a wheel sensor, a speed sensor, a slope sensor, a weight sensor, a heading sensor, a position module, a vehicle forward / backward sensor, a battery sensor, a fuel sensor, a tire sensor, a steering sensor, a temperature sensor, a humidity sensor, an ultrasonic sensor, an illuminance sensor, a pedal position sensor, etc. The autonomous driving unit 140d can implement technologies for keeping the lane on which the vehicle is driving, technologies for automatically adjusting speed such as adaptive cruise control, technologies for autonomously driving along a determined path, technologies for driving by automatically setting a path when a destination is set, etc.

[0651] For example, the communication unit 110 can receive map data, traffic information data, etc. from an external server. The autonomous driving unit 140d can generate an autonomous driving path and a driving plan from the obtained data. The control unit 120 can control the driving unit 140a so that the vehicle or autonomous driving vehicle 100 can move along the autonomous driving path according to the driving plan (e.g., speed / direction control). During autonomous driving, the communication unit 110 can obtain the latest traffic information data from the external server irregularly / regularly, and can obtain surrounding traffic information data from neighboring vehicles. During autonomous driving, the sensor unit 140c can acquire vehicle state and / or surrounding environment information. The autonomous driving unit 140d can update the autonomous driving path and the driving plan based on the newly obtained data / information. The communication unit 110 can transmit information about the vehicle position, the autonomous driving path, and / or the driving plan to the external server. The external server can predict traffic information data using AI technology, etc. based on the information collected from the vehicle or autonomous driving vehicle, and provide the predicted traffic information data to the vehicle or autonomous driving vehicle.

[0652] Here, the wireless communication technologies implemented in the wireless devices (XXX, YYY) of this specification may include LTE, NR, and 6G, as well as narrowband Internet of Things for low-power communication. At this time, for example, the NB-IoT technology may be an example of a low-power wide area network (LPWAN) technology, and may be implemented in standards such as LTE Cat NB1 and / or LTE Cat NB2, and is not limited to the above names. Additionally or alternatively, the wireless communication technologies implemented in the wireless devices (XXX, YYY) of this specification may perform communication based on the LTE-M technology. In this case, as an example, the LTE-M technology may be an example of an LPWAN technology, and may be referred to by various names such as eMTC (enhanced machine type communication). For example, the LTE-M technology may be implemented in at least one of various standards, such as: 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-BL (non-bandwidth limited), 5) LTE-MTC, 6) LTE machine type communication, and / or 7) LTE M, and is not limited to the above names. Additionally or alternatively, the wireless communication technologies implemented in the wireless devices (XXX, YYY) of this specification are at least one of ZigBee, Bluetooth, and low-power wide area network (LPWAN) considering low-power communication, and are not limited to the above names. As an example, the ZigBee technology may generate a personal area network (PAN) related to small / low-power digital communication based on various standards such as IEEE 802.15.4, and may be called various names.

[0653] The above-described embodiments are embodiments in which the components and features of the present disclosure are combined in a predetermined form. Unless otherwise clearly stated, each component or feature should be considered optional. Each component or feature may be implemented in a form that does not combine with other components or features. In addition, embodiments of the present disclosure may also be constituted by combining some components and / or features. The operation order described in the embodiments of the present disclosure may be changed. Some configurations or features of one embodiment may be included in other embodiments, or may be replaced with corresponding configurations or features of other embodiments. Obviously, embodiments may be configured by combining claims that do not have an explicit citation relationship, or may be included as new claims by modification after submission.

[0654] In this document, embodiments of the present disclosure are mainly described based on the signal transmission / reception relationship between a terminal and a base station. This transmission / reception relationship is extended to the signal transmission / reception between a terminal and a repeater or between a base station and a repeater in the same / similar manner. In some cases, specific operations described in this document as being performed by a base station may be performed by its upper-level node. That is, it is obvious that various operations for communicating with a terminal in a network including multiple network nodes including a base station may be performed by the base station or a network node other than the base station. The base station may be replaced with terms such as a fixed station, Node B, eNode B (eNB), access point, etc. In addition, the terminal may be replaced with terms such as user equipment (UE), mobile station (MS), mobile subscriber station (MSS), etc.

[0655] In terms of hardware configuration, embodiments of the present disclosure may be implemented by one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, etc.

[0656] In terms of firmware or software configuration, the method according to embodiments of the present disclosure may be implemented in the form of modules, processes, functions, etc. The software code may be stored in a memory unit and executed by a processor. The memory unit is located inside or outside the processor and may send data to and receive data from the processor via various known means.

[0657] As described above, a detailed description of the preferred embodiments of the present disclosure has been given so that those skilled in the art can implement and execute the present disclosure. Although the above has referred to the preferred embodiments of the present disclosure, those skilled in the art will understand that various modifications and changes can be made to the present disclosure within the scope of the present disclosure. For example, those skilled in the art can use the components described in the foregoing embodiments in combination. Therefore, the above embodiments are to be construed as illustrative in all aspects and not restrictive. The scope of the present disclosure should be determined by the appended claims and their legal equivalents, rather than by the above description, and all changes falling within the meaning and equivalent scope of the appended claims are intended to be included therein.

[0658] Industrial Applicability

[0659] The present disclosure is applicable to UEs, BSs, or other devices in a wireless mobile communication system.

Claims

1. A method performed by a first user equipment (UE) in a wireless communication system supporting one or more radio access technologies (RATs) including a first RAT, the method comprising the steps of: receiving information about a second UE from the second UE via a second RAT connection between the first UE and the second UE; sending a first-RAT-based signal including the information about the second UE received via the second RAT connection to a base station (BS); and receiving, from the BS, configuration information for an indirect path between the first UE and the BS via the second UE, wherein the information about the second UE received via the second RAT connection includes a UE identifier assigned to the second UE by the BS based on the first RAT.

2. The method according to claim 1, wherein the UE identifier of the second UE is a cell-radio network temporary identifier (C-RNTI) of the second UE.

3. The method according to claim 2, wherein the C-RNTI of the second UE is sent to the BS to report to the BS that the second UE is in a radio resource control (RRC) connection state based on the first RAT.

4. The method according to claim 1, wherein the second UE is a candidate for a relay UE configured for the indirect path.

5. The method according to claim 4, wherein the configuration information for the indirect path includes information about the relay UE.

6. The method according to claim 4, wherein the relay UE is determined based on the first-RAT-based signal sent by the first UE.

7. The method according to claim 1, wherein the first UE is a remote UE configured with a direct path to the BS, and wherein the direct path is configured by performing a random access procedure with the BS.

8. The method according to claim 1, wherein the indirect path includes a first RAT connection between the second UE and the BS and the second RAT connection between the first UE and the second UE.

9. The method according to claim 1, wherein the first RAT is a 3rd Generation Partnership Project (3GPP) RAT and the second RAT is a non-3GPP RAT, and wherein the second RAT connection is different from a 3GPP sidelink connection.

10. A computer-readable medium storing instructions that, when executed by a processor, cause the processor to perform the method according to claim 1.

11. A method performed by a base station (BS) in a wireless communication system supporting one or more radio access technologies (RATs) including a first RAT, the method comprising the steps of: receiving a second-RAT-based signal including information about one or more UEs from a first user equipment (UE); determining configuration information for an indirect path between the first UE and the BS via a second UE; and and Send the configuration information for the indirect path to the first UE. wherein the information about one or more UEs includes information about a second UE having a second RAT connection with the first UE, and wherein the information about the second UE includes a UE identifier assigned to the second UE by the BS based on the first RAT.

12. A first device in a wireless communication system supporting one or more radio access technologies (RATs) including a first radio access technology (RAT), the first device comprises: a memory configured to store instructions; and a processor configured to perform operations by executing the instructions, wherein the operations performed by the processor include: receiving, via a second RAT connection between the first device and a second device, information about the second device; sending a first-RAT-based signal including the information about the second device received via the second RAT connection to a base station (BS); and receiving, from the BS, configuration information for an indirect path via a second UE between the first device and the BS, wherein the information about the second device received via the second RAT connection includes a device identifier assigned to the second device by the BS based on the first RAT.

13. The first device according to claim 12, the first device further comprises: a transceiver, wherein the first device is a user equipment (UE) in a wireless communication system.

14. The first device according to claim 12, wherein the first device is a processing device configured to control a user equipment (UE) in a wireless communication system.

15. A base station (BS) in a wireless communication system supporting one or more radio access technologies (RATs) including a first radio access technology (RAT), the BS comprises: a memory configured to store instructions; and a processor configured to perform operations by executing the instructions, wherein the operations performed by the processor include: receiving, from a first user equipment (UE), a second-RAT-based signal including information about one or more UEs; determining configuration information for an indirect path via a second UE between the first UE and the BS; and sending the configuration information for the indirect path to the first UE, wherein the information about one or more UEs includes information about a second UE having a second RAT connection with the first UE, and wherein the information about the second UE includes a UE identifier assigned to the second UE by the BS based on the first RAT.

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