Method executed by user equipment and user equipment

Abstract

Provided in the present invention are a method executed by a user equipment and a user equipment. The method comprises: receiving a measurement configuration sent by a network; if a UE is configured with the measurement configuration, executing a measurement associated with a connected relay UE, or executing a measurement associated with a next-hop UE; and reporting a measurement report to the network, wherein the measurement report includes a measurement result of the connected relay UE or the next-hop UE.

Description

Method performed by a user equipment and user equipment TECHNICAL FIELD

[0001] The present invention relates to the field of wireless communication technology, and more specifically, to a communication method based on multi-hop U2N relay architecture performed by a user equipment and a corresponding user equipment. BACKGROUND

[0002] In March 2020, at RAN#91 plenary, a work item on NR sidelink relaying for Release 17 was proposed (see non-patent literature: RP-210904 New Study Item on NR Sidelink Relaying) and approved. The latest version of this work item can be found in the non-patent literature: RP-212601 revised WID NR sidelink relay. One of the objectives of this work item is to standardize the procedures for sidelink U2N (UE-to-Network) relay architecture. In U2N relay architecture, the remote UE and the network communicate through a relay UE.

[0003] In December 2021, at RAN#94 plenary, a work item on NR sidelink relay enhancements for Release 18 was proposed (see non-patent literature: RP-213585 New WID on NR sidelink relay enhancements) and approved. The latest version of this work item can be found in the non-patent literature: RP-221262 Revised WID on NR sidelink relay enhancements. One of the objectives of this work item is to standardize the control plane procedures for U2U (UE-to-UE) relay architecture. In U2U relay architecture, two remote UEs communicate through a relay UE.

[0004] In June 2024, at RAN#104 plenary, a work item on NR sidelink multi-hop relay for Release 19 was proposed (see non-patent literature: RP-241609 NR sidelink multi-hop relay) and approved. The objective of this work item is to standardize multi-hop L2 U2N relay. SUMMARY

[0005] To solve at least one of the above problems, the present application provides a method performed by a user equipment and a user equipment, which can realize measurement and measurement result reporting for a relay UE connected by the UE, and effectively perform connection establishment with a target side relay UE and connection release with a source side relay UE.

[0006] According to the present application, a method performed by a user equipment UE is provided, comprising: receiving a measurement configuration sent by a network; if the UE is configured with the measurement configuration, performing measurement associated with a connected relay UE, or performing measurement associated with a next hop UE; and reporting a measurement report to the network, wherein the measurement report contains measurement results of the connected relay UE or the next hop UE.

[0007] Preferably, in the step of reporting the measurement report to the network, the UE performs at least one of the following operations:

[0008] - setting a connected relay UE identifier, indicating an identifier of a relay UE connected by the UE;

[0009] - setting a next hop UE identifier, indicating an identifier of a next hop UE;

[0010] - setting a measurement result, containing a SL-RSRP or a SD-RSRP of the relay UE connected by the UE; and

[0011] - setting a measurement result, containing a SL-RSRP or a SD-RSRP of the next hop UE.

[0012] Further, according to the present application, a method performed by a user equipment UE is provided, comprising: receiving a dedicated RRC message sent by a network, wherein the RRC message contains synchronization reconfiguration and / or sidelink path switching configuration; and triggering connection establishment with a target side relay UE according to the received RRC message.

[0013] Preferably, the sidelink path switching configuration contains at least one of the following information:

[0014] - a multi-hop indication;

[0015] - a target side relay UE identifier;

[0016] - a target side relay UE list;

[0017] - a target side last relay UE identifier;

[0018] a target side intermediate relay UE identifier; and

[0019] a target side intermediate relay UE list.

[0020] Preferably, in the step of triggering and target side relay UE to establish connection, the UE judges at least one of the following conditions:

[0021] -the UE is a remote UE or is acting as a remote UE at the source side;

[0022] -the RRC message contains a sidelink path switch configuration;

[0023] -the UE is directly connected to the network at the source side;

[0024] -the UE is indirectly connected to the network with single hop at the source side; and

[0025] -the multi-hop indication indicates that the target side path is multi-hop indirect connection,

[0026] In the case that the UE meets at least one of the above conditions, the PC5 unicast link establishment between the upper layer trigger and the target side relay UE is instructed.

[0027] Preferably, in the step of triggering and target side relay UE to establish connection, the UE judges at least one of the following conditions:

[0028] -the UE is an intermediate relay UE or is acting as an intermediate relay UE at the source side;

[0029] -the RRC message contains a sidelink path switch configuration;

[0030] -the UE is directly connected to the network at the source side;

[0031] -the UE is indirectly connected to the network with single hop at the source side; and

[0032] -the multi-hop indication indicates that the target side path is multi-hop indirect connection,

[0033] In the case that the UE meets at least one of the above conditions, the PC5 unicast link establishment between the upper layer trigger and the target side relay UE is instructed.

[0034] In addition, according to the present application, a method performed by a user equipment UE is proposed, comprising: receiving a dedicated RRC message sent by a network, the RRC message containing a synchronization reconfiguration and / or a sidelink path switch configuration; and triggering and source side relay UE to release connection according to the received RRC message.

[0035] Preferably, in the step of triggering and source side relay UE to release connection, the UE judges at least one of the following conditions:

[0036] -the UE is a remote UE or is acting as a remote UE at the source side;

[0037] -the RRC message contains a sidelink path switch configuration;

[0038] - the UE is multi-hop indirectly connected to the network at the source side; and

[0039] - the multi-hop indication indicates that the target path is single-hop indirectly connected,

[0040] In case the UE meets at least one of the above conditions, the UE performs at least one of the following operations:

[0041] - indicating the upper layer to trigger the release of the PC5 unicast link between the UE and a serving relay UE connected at the source side;

[0042] - indicating the upper layer to trigger the release of the PC5 unicast link between the UE and a first relay UE at the source side;

[0043] - indicating the upper layer to trigger the release of the PC5 unicast link between the UE and a relay UE or an intermediate relay UE connected at the source side; and

[0044] - indicating the upper layer to trigger the release of the PC5 unicast link between the UE and a next-hop UE at the source side.

[0045] Preferably, in the step of triggering the release of the connection of the relay UE at the source side, the UE judges at least one of the following conditions:

[0046] - the UE is an intermediate relay UE or is acting as an intermediate relay UE at the source side;

[0047] - the RRC message contains a sidelink communication path switch configuration;

[0048] - the UE is multi-hop indirectly connected to the network at the source side; and

[0049] - the multi-hop indication indicates that the target path is single-hop indirectly connected,

[0050] In case the UE meets at least one of the above conditions, the UE performs at least one of the following operations:

[0051] - indicating the upper layer to trigger the release of the PC5 unicast link between the UE and a serving relay UE connected at the source side;

[0052] - indicating the upper layer to trigger the release of the PC5 unicast link between the UE and a second relay UE at the source side;

[0053] - indicating the upper layer to trigger the release of the PC5 unicast link between the UE and a last relay UE connected at the source side;

[0054] - indicating the upper layer to trigger the release of the PC5 unicast link between the UE and a relay UE or an intermediate relay UE connected at the source side; and

[0055] - Instructs the upper layer to trigger the release of the PC5 unicast link between the UE and the source-side next-hop UE.

[0056] Furthermore, according to the present invention, a user equipment is provided, comprising: a processor; and a memory storing instructions, wherein the instructions, when executed by the processor, perform the methods described above.

[0057] According to the present invention, it is possible to perform measurements and report measurement results for the relay UEs connected to the UE, and effectively perform connection establishment with the target relay UE and connection release with the source relay UE. Attached Figure Description

[0058] Figure 1 is a schematic diagram of the U2N relay architecture.

[0059] Figure 2 is a schematic diagram of a multi-hop U2N relay architecture.

[0060] Figure 3 is a schematic diagram of method one executed by the UE according to one or more embodiments.

[0061] Figure 4 is a schematic diagram of method two executed by the UE according to one or more embodiments.

[0062] Figure 5 is a schematic diagram of method three executed by the UE according to one or more embodiments.

[0063] Figure 6 is a schematic diagram of method four executed by the UE according to one or more embodiments.

[0064] Figure 7 is a schematic diagram of method five executed by the UE according to one or more embodiments.

[0065] Figure 8 is a schematic diagram of method six performed by the UE according to one or more embodiments.

[0066] Figure 9 is a schematic diagram of method seven executed by the UE according to one or more embodiments.

[0067] Figure 10 is a schematic diagram of method eight performed by the UE according to one or more embodiments.

[0068] Figure 11 is a simplified structural block diagram of the user equipment (UE) involved in this invention. Detailed Implementation

[0069] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should be noted that the present invention should not be limited to the specific embodiments described below. Furthermore, for the sake of simplicity, detailed descriptions of well-known technologies not directly related to the present invention have been omitted to prevent confusion in understanding the present invention.

[0070] The following describes some of the terms involved in this invention. For the specific meanings of these terms, please refer to the latest 3GPP standard specifications.

[0071] UE: User Equipment

[0072] NR: New Radio

[0073] PHY: physical layer

[0074] MAC: Medium Access Control

[0075] RLC: Radio Link Control

[0076] SDAP: Service Data Adaptation Protocol

[0077] PDCP: Packet Data Convergence Protocol

[0078] SRAP: Sidelink Relay Adaptation Protocol

[0079] RRC: Radio Resource Control

[0080] RRC_CONNECTED: RRC connected state

[0081] RRC_INACTIVE: RRC inactive state

[0082] RRC_IDLE: RRC idle state

[0083] RAN: Radio Access Network

[0084] NG-RAN: NG Radio Access Network

[0085] gNB: the next Generation Node B

[0086] Sidelink: sidelink

[0087] SL: Sidelink

[0088] SCI: Sidelink Control Information, sidelink control information

[0089] AS: Access Stratum, access stratum

[0090] IE: Information Element, information element

[0091] CE: Control Element, control element

[0092] MIB: Master Information Block, master information block

[0093] SIB: System Information Block, system information block

[0094] DCI: Downlink Control Information, downlink control information

[0095] RB: radio bearer, radio bearer

[0096] DRB: Data Radio Bearer, data radio bearer

[0097] SRB: Signalling Radio Bearer, signalling radio bearer

[0098] Uu: air interface

[0099] ProSe: Proximity based Services: proximity-based services

[0100] V2X: Vehicle-to-Everything, vehicle-to-everything

[0101] NAS: Non-Access-Stratum, non-access stratum

[0102] PC5-S: PC5 signalling, pc5 signaling

[0103] SL-SRB: Sidelink Signalling Radio Bearer, sidelink signalling radio bearer

[0104] SL-DRB: Sidelink Data Radio Bearer, sidelink data radio bearer

[0105] U2U: UE-to-UE, ue-to-ue

[0106] U2N: UE-to-Network, UE to network

[0107] L2: Layer 2, Layer two architecture

[0108] RSRP: Reference Signal Received Power, Reference signal received power

[0109] SL-RSRP: Sidelink RSRP, Sidelink reference signal received power

[0110] SD-RSRP: sidelink discovery RSRP, Sidelink discovery message reference signal received power

[0111] SpCell: Special Cell, Special cell, including PCell and PSCell

[0112] PCell: Primary Cell, Primary cell

[0113] PSCell: Primary SCG Cell, Primary scg cell

[0114] L2-ID: Layer-2 ID (identity), Layer two identity

[0115] 3GPP: 3rd Generation Partnership Project, Third generation partnership project

[0116] RLF: radio link failure, Radio link failure

[0117] In the present application, network (network or NW), base station (base station or gNB or eNB) and RAN can be used interchangeably, and the network can be a long term evolution (LTE) network, a new radio access technology (NR) network, an enhanced long term evolution (eLTE) network, or other networks defined in subsequent evolution versions of 3GPP. The base station in the present application can be any type of base station, including Node B, enhanced base station (eNB), 5G communication system base station (gNB), or micro base station, pico base station, macro base station, home base station, etc. The network generally refers to a base station or a cell. The cell can also be a cell under any type of base station described above. If not otherwise specified, cell, beam, transmission point (TRP) can be used interchangeably, and the base station can be a central unit (gNB-CU) or a distributed unit (gNB-DU) of the base station.

[0118] In the present application, user equipment (UE) can refer to an NR device supporting NR Sidelink Relay function as described in the background art, or an NR device supporting L2 U2N Relay function, or an NR device supporting multi-hop L2 U2N Relay function, or other types of NR devices or LTE devices.

[0119] In the present application, Sidelink, SL and PC5 can be used interchangeably.

[0120] In the present application, "change" and "update" can be used interchangeably.

[0121] In the present application, "configure", "set", "present" can be used interchangeably.

[0122] In the present application, "used", "available", "active", "applied", "performed", "enabled" can be used interchangeably.

[0123] In the present application, "use", "make available", "apply", "implement", "enable", "activate", "perform", "do" and the like can be used interchangeably.

[0124] In the present disclosure, “associate”, “correspond”, “map” can be used interchangeably.

[0125] In the present disclosure, “receive”, “detect”, “monitor”, “acquire”, “derive” can be replaced with each other.

[0126] In the present disclosure, “feedback”, “submit”, “report”, “send”, “transmit”, “inform”, “indicate”, “provide”, “forward” can be used interchangeably.

[0127] In the present disclosure, “trigger” and “initiate” can be used interchangeably.

[0128] In the present disclosure, “upper layer” can refer to ProSe layer, or V2X layer, or NAS layer, or PC5-S protocol layer. In the present disclosure, ProSe layer, V2X layer, NAS layer and PC5-S protocol layer can be used interchangeably.

[0129] In the present disclosure, “channel” can refer to one channel, or multiple channels.

[0130] In the present disclosure, “first hop”, “second hop” and “third hop” can all be modified by “PC5”, that is, “first hop”, “second hop” and “third hop” are all based on PC5 interface.

[0131] In the present disclosure, “relay UE”, “U2N relay UE” and “L2 U2N relay UE” can be used interchangeably, and “NR Sidelink” can be added as a prefix before these names.

[0132] In the present disclosure, “remote UE”, “U2N remote UE” and “L2 U2N remote UE” can be used interchangeably, and “NR Sidelink” can be added as a prefix before these names.

[0133] It should be noted that in the present specification, two connected by "and", "or", "and / or" can represent different expressions of the same intention in different application scenarios, and there may be a relationship between inclusion and inclusion, not necessarily referring to completely different content.

[0134] The related art of the present application is described below.

[0135] PC5 interface

[0136] The PC5 interface is an interface for control plane and user plane Sidelink communication between UEs. Upper layer establishes a PC5 unicast link for Sidelink unicast communication, and one PC5 unicast link establishment corresponds to one PC5-RRC connection establishment. For Sidelink unicast, the PC5-RRC connection is an AS layer logical connection between a pair of source L2 ID and destination L2 ID.

[0137] Uu interface

[0138] The Uu interface is a wireless communication interface between a UE and a base station. The UE can communicate with the gNB on the Uu interface using NR.

[0139] L2 architecture

[0140] The L2 architecture is relative to the L3 architecture. In the L2 architecture, the selection and reselection of relays and the communication of UEs through relays and networks or another UE need to be controlled or participated by the access layer. In the L3 architecture, the access layer is basically unaware of the existence of the relay, or the relay is transparent to the access layer.

[0141] U2N (UE-to-Network) relay

[0142] The UE-to-Network relay is shown in FIG. 1, with the Remote UE on the left, the Relay UE in the middle, and the network on the right. The Remote UE and the Relay UE are connected by the PC5 interface, and the Relay UE and the network are connected by the Uu interface. Because the Remote UE is far away from the network or the communication environment is poor, the Relay UE is needed to relay and forward the signaling and data between the two.

[0143] For U2N relay architecture, U2N Remote UE refers to a UE that communicates with the network through a U2N Relay UE. L2 U2N Remote UE refers to a U2N Remote UE in L2 architecture. U2N Relay UE refers to a UE that provides functions to support a U2N Remote UE to connect to the network. L2 U2N Relay UE refers to a U2N Relay UE in L2 architecture.

[0144] After the Remote UE selects a Relay UE to provide relay service for itself, the Remote UE establishes a PC5-RRC connection with the Relay UE to communicate with the network through the Relay UE. The Remote UE can establish an air interface RRC connection with the network through the Relay UE for data transmission between the Remote UE and the network.

[0145] The L2 U2N architecture shown in FIG. 1 is a one-hop U2N relay, i.e., the Remote UE communicates with the network through one Relay UE.

[0146] Multi-hop U2N relay

[0147] In one-hop U2N relay, there is only one U2N Relay UE, and its coverage is limited. Multi-hop U2N relay is shown in FIG. 2, in which the Remote UE communicates with the network through multiple Relay UEs. Multi-hop U2N relay can expand the coverage. The U2N Relay UE that is directly connected to the network is called the “last U2N Relay UE”. As shown in FIG. 2, the first U2N Relay UE and the second U2N Relay UE can both be called “intermediate U2N Relay UE”. In multi-hop U2N relay architecture, the number of intermediate U2N Relay UEs can be one or more. For example, in a multi-hop U2N relay architecture with two intermediate U2N Relay UEs, the Remote UE is connected to the first U2N Relay UE through a PC5 interface, the first U2N Relay UE is connected to the second U2N Relay UE through a PC5 interface, the second U2N Relay UE is connected to the last U2N Relay UE through a PC5 interface, and the last U2N Relay UE is connected to the network through a Uu interface.

[0148] The Remote UE establishes a (Uu) RRC connection with the network, a Uu SRB for transmitting signaling, and a Uu DRB for transmitting data.

[0149] PC5 Relay RLC channel is an RLC channel between L2 U2N Remote UE and L2 U2N Relay UE, or between two L2 U2N Relay UEs, or between L2 U2N Relay UE and L2 U2N Relay UE, for L2 U2N relay to transmit packets over PC5 interface. For PC5 Relay RLC channel between two L2 U2N Relay UEs, both of the two L2 U2N Relay UEs are intermediate U2N Relay UEs, or one of the two L2 U2N Relay UEs is last U2N Relay UE and the other is intermediate U2N Relay UE.

[0150] Uu Relay RLC channel is an RLC channel between L2 U2N Relay UE and base station, or between last L2 U2N Relay UE and base station, for L2 U2N relay to transmit packets over Uu interface.

[0151] PC5 Relay RLC channel for sending and receiving messages on SRB0 of Remote UE is referred to as SL-RLC0; or PC5 Relay RLC channel for sending and receiving messages on SRB0 of Remote UE adopts a protocol specified RLC configuration, PC5 Relay RLC channel adopting such RLC configuration is referred to as SL-RLC0.

[0152] PC5 Relay RLC channel for sending and receiving messages on SRB1 of Remote UE is referred to as SL-RLC1; PC5 Relay RLC channel for sending and receiving messages on SRB1 of Remote UE can adopt a default RLC configuration, PC5 Relay RLC channel adopting such RLC configuration is referred to as SL-RLC1.

[0153] Path switch

[0154] The connection established by the UE and the network for data transmission can be considered as a data path or a data connection. The connection of the UE to the network through the Uu interface can be considered as a direct path. The connection of the UE to the network through a Relay UE can be considered as an indirect path. The connection of the UE to the network through different Relay UEs can be considered as different data paths. The change of the data path can be referred to as path switch. The UE in the RRC_CONNECTED state can perform path switch, which is initiated by the network. The data path before path switch is the source side path, and the data path after path switch is the target side path. Path switch includes direct-to-indirect path switch, indirect-to-direct path switch, and indirect-to-indirect path switch.

[0155] For direct-to-indirect path switch and indirect-to-indirect path switch, the network configures the Remote UE in the RRC_CONNECTED state with measurement parameters, and the Remote UE reports a measurement report to the network. The network determines whether to switch the Remote UE to be connected to the network through a Relay UE according to the measurement report. After determining a target Relay UE, the network prepares to initiate path switch, and configures the Remote UE related parameters for the target side Relay UE through an RRCReconfiguration message. The network sends the RRCReconfiguration message to the Remote UE, initiates path switch by including the sl-PathSwitchConfig field in the message, and includes the information of the target side Relay UE. The Remote UE initiates PC5 connection establishment to the target side Relay UE, and sends an RRCReconfigurationComplete message to the network after the PC5 connection is established. The message is forwarded to the network through the Relay UE, and the path switch process is completed.

[0156] For indirect-to-direct path switch, the network sends a RRCReconfiguration message to the Remote UE, which contains a synchronization reconfiguration but does not contain the sl-PathSwitchConfig field. The Remote UE releases the PC5 connection between the Remote UE and the source-side Relay UE, and sends a RRCReconfigurationComplete message to the network.

[0157] The present application discusses the control plane procedures of Remote UE and Relay UE in multi-hop U2N relay architecture, and the related processing of path switch. Through the present application, the control plane procedures of UE can be correctly executed to realize sidelink communication through relay, and the related procedures of path switch can be correctly and timely executed to switch to a suitable path, so as to maintain the continuity of service.

[0158] Hereinafter, several embodiments of the present application for solving the above problems will be described in detail.

[0159] In the following several embodiments, the same nouns can represent the same meanings, and the same parameter names represent the same meanings.

[0160] It is self-evident that the present application also includes other implementation methods not mentioned herein, which can achieve other effects not mentioned herein.

[0161] The following several embodiments are described taking multi-hop U2N relay architecture as an example.

[0162] First, the expressions in the embodiments are explained.

[0163] The "last U2N Relay UE" refers to a UE (or U2N Relay UE) that is connected to the network through a Uu interface (directly) and provides functions to support the connection of a U2N Remote UE to the network. In the present application, the "last U2N Relay UE", "root U2N Relay UE", "parent U2N Relay UE", "father U2N Relay UE", "last L2 U2N Relay UE", "root L2 U2N Relay UE", "parent L2 U2N Relay UE" and "father L2 U2N Relay UE" can be used interchangeably.

[0164] “Intermediate U2N Relay UE” refers to a UE that has no direct connection with the network, is connected (directly) with the last U2N Relay UE or another (or other) intermediate U2N Relay UE through PC5 interface, and provides functions to support a U2N Remote UE to connect to the network. In a multi-hop U2N architecture, the number of intermediate U2N Relay UEs can be one or more. In this invention, “intermediate (or middle, etc.) U2N Relay UE”, “child U2N Relay UE”, “son U2N Relay UE”, “leave U2N Relay UE”, “intermediate L2 U2N Relay UE”, “child L2 U2N Relay UE”, “son L2 U2N Relay UE”, and “leave L2 U2N Relay UE” can be used interchangeably.

[0165] “Last U2N Relay UE” and “Intermediate U2N Relay UE” are both U2N Relay UEs, i.e., a U2N Relay UE includes “Last U2N Relay UE” and “Intermediate U2N Relay UE”.

[0166] “First U2N Relay UE” refers to a UE that is connected (directly) with a U2N Remote UE through PC5 interface, is connected (directly) with the last U2N Relay UE or (other) intermediate U2N Relay UE through PC5 interface, and provides functions to support a U2N Remote UE to connect to the network (or a U2N Relay UE, or an intermediate U2N Relay UE). Alternatively, the first U2N Relay UE refers to an intermediate U2N Relay UE (or a U2N Relay UE) that is connected (directly) with a U2N Remote UE through PC5 interface.

[0167] “Second U2N Relay UE” refers to a UE that is connected (directly) with the first U2N Relay UE through PC5 interface, is connected (directly) with the last U2N Relay UE or (other) intermediate U2N Relay UE through PC5 interface, and provides functions to support a U2N Remote UE to connect to the network (or a U2N Relay UE, or an intermediate U2N Relay UE). Alternatively, the second U2N Relay UE refers to an intermediate U2N Relay UE (or a U2N Relay UE) that is connected (directly) with the first U2N Relay UE through PC5 interface.

[0168] By analogy, the n-th U2N Relay UE is connected (directly) with the (n-1)-th U2N Relay UE through PC5 interface, and the last U2N Relay UE is connected (directly) with the last U2N Relay UE through PC5 interface, providing functions to support the U2N Remote UE to connect to the network UE (or U2N Relay UE, or intermediate U2N Relay UE). Alternatively, the n-th U2N Relay UE is connected (directly) with the (n-1)-th U2N Relay UE through PC5 interface, and the last U2N Relay UE is connected (directly) with the last U2N Relay UE through PC5 interface, providing functions to support the U2N Remote UE to connect to the network UE (or U2N Relay UE, or intermediate U2N Relay UE).

[0169] The first U2N Relay UE, the second U2N Relay UE, and by analogy, the n-th U2N Relay UE are all intermediate U2N Relay UEs. The “first U2N Relay UE” and the “first L2 U2N Relay UE” can be used interchangeably, and the “second U2N Relay UE” and the “second L2 U2N Relay UE” can be used interchangeably.

[0170] The “previous-hop UE” refers to the UE that is closer to the U2N Remote UE (for a certain U2N Remote UE or for a certain multi-hop indirect path) and is directly connected to the current UE in the multi-hop L2N relay architecture. The “previous-hop UE” is an (intermediate) U2N Relay UE or a U2N Remote UE or a first / second U2N Relay UE.

[0171] The “next-hop UE” refers to the UE that is closer to the network (for a certain U2N Remote UE or for a certain multi-hop indirect path) and is directly connected to the current UE in the multi-hop L2N relay architecture. The “next-hop UE” is an (intermediate) U2N Relay UE or a last U2N Relay UE or a first / second U2N Relay UE.

[0172] Alternatively, the meaning of “previous-hop UE” or “next-hop UE” is interchangeable, then all “previous-hop UEs” in the following embodiments need to be changed to “next-hop UEs”, and all “next-hop UEs” need to be changed to “previous-hop UEs”.

[0173] Embodiments

[0174] FIG. 3 is a schematic diagram of a method one performed by a UE according to one or more embodiments. The UE can perform one or more steps in FIG. 3. FIG. 3 includes steps S101-S103.

[0175] The network can determine whether and how to perform path switching according to the measurement report reported by the UE.

[0176] Optionally, in step S101, the UE receives the measurement configuration sent by the network. Optionally, the measurement configuration is contained in a dedicated RRC message (for example: RRC reconfiguration message).

[0177] Optionally, in step S102, if the UE is configured with the measurement configuration, the UE performs the measurement associated with the connected L2 U2N Relay UE, or the UE performs the measurement associated with the next hop UE.

[0178] Optionally, when the UE is a L2 U2N Remote UE (and / or the UE has the capability of L2 U2N Remote UE, and / or the UE is acting as a L2 U2N Remote UE, and / or the UE supports L2 U2N Remote UE operation), the connected L2 U2N Relay UE (or the next hop UE) is the first U2N Relay UE, or is the intermediate U2N Relay UE.

[0179] Optionally, when the UE is a L2 U2N Relay UE (and / or the UE has the capability of L2 U2N Relay UE, and / or the UE is acting as a L2 U2N Relay UE, and / or the UE supports L2 U2N Relay UE operation), the connected L2 U2N Relay UE (or the next hop UE) is the last U2N Relay UE, or is the second U2N Relay UE, or is the intermediate U2N Relay UE.

[0180] Optionally, in step S103, the UE reports the measurement report to the network. Optionally, the measurement report contains the measurement result of the connected L2 U2N Relay UE (or the next hop UE).

[0181] Optionally, the UE performs at least one of the following operations:

[0182] - setting the connected Relay UE identity, indicating the identity of the L2 U2N Relay UE connected by the UE (identity: L2 ID, or source L2 ID, or target L2 ID);

[0183] - set next hop UE identity, indicating the identity of the next hop UE (identity e.g. L2 ID, or source L2 ID, or target L2 ID);

[0184] - set measurement result, containing SL-RSRP (or SD-RSRP) of the L2 U2N Relay UE that the UE is connected to;

[0185] - set measurement result, containing SL-RSRP (or SD-RSRP) of the next hop UE.

[0186] Figure 4 is a schematic diagram of a method two performed by a UE according to one or more embodiments. The UE can perform one or more steps in Figure 4. Figure 4 includes steps S201-S202.

[0187] Figure 4 is for the path switching scenario of direct connection to multi-hop indirect connection, or single-hop indirect connection to multi-hop indirect connection.

[0188] Optionally, in step S201, the UE receives a dedicated RRC message (e.g. RRCReconfiguration) sent by the network. Optionally, the RRC message contains reconfigurationWithSync, and / or Sidelink path switch configuration. Optionally, the Sidelink path switch configuration is contained in reconfigurationWithSync.

[0189] Optionally, the Sidelink path switch configuration contains at least one of the following information:

[0190] - multi-hop indication;

[0191] - target side Relay UE identity (identity e.g. source L2 ID, or target L2 ID);

[0192] - target side Relay UE list;

[0193] - target side last U2N Relay UE identity (identity e.g. source L2 ID, or target L2 ID);

[0194] - target side intermediate U2N Relay UE identity (identity e.g. source L2 ID, or target L2 ID);

[0195] - target side intermediate U2N Relay UE list.

[0196] Wherein, optionally, the multi-hop indication is used to indicate whether the switched target side path is multi-hop.

[0197] Optionally, the target side Relay UE identity indicates an identity of the target side Relay UE for indicating the path switch.

[0198] Optionally, the target side Relay UE list indicates target side path U2N Relay UE information, including one or more target side Relay UE identities (identity e.g. source L2 ID, or target L2 ID). Optionally, the first entry (i.e. first target side Relay UE identity) in the target side Relay UE list indicates the U2N Relay UE or next hop UE (e.g. first U2N Relay UE) connected to the UE, the second entry (i.e. second target side Relay UE identity) indicates the U2N Relay UE or next hop UE (e.g. second U2N Relay UE, or last U2N Relay UE) connected to the U2N Relay UE indicated by the first target side Relay UE identity, and so on.

[0199] Optionally, the target side intermediate U2N Relay UE identity indicates an intermediate U2N Relay UE (e.g. first U2N Relay UE) connected to the UE.

[0200] Optionally, the target side intermediate U2N Relay UE list indicates target side path intermediate U2N Relay UE information, including one or more target side intermediate U2N Relay UE identities. Optionally, the first entry (i.e. first target side intermediate U2N Relay UE identity) in the target side Relay UE list indicates the target side intermediate U2N Relay UE (e.g. first U2N Relay UE) connected to the UE, the second entry (i.e. second target side intermediate U2N Relay UE identity) indicates the intermediate U2N Relay UE (e.g. second U2N Relay UE, or last U2N Relay UE) connected to the U2N Relay UE indicated by the first target side intermediate U2N Relay UE identity, and so on.

[0201] Optionally, the target side last U2N Relay UE identity indicates the path switch target side last U2N Relay UE. The target side intermediate U2N Relay UE identity indicates the path switch target side intermediate U2N Relay UE.

[0202] Optionally, in step S202, the UE triggers and the target side U2N Relay UE establishes a connection.

[0203] Optionally, the UE judges at least one of the following conditions:

[0204] - the UE is (or: is being) a L2 U2N Remote UE at the source side;

[0205] - the RRC message contains a Sidelink Path Switching Configuration;

[0206] - the UE is directly connected to the network at the source side;

[0207] - the UE is indirectly connected to the network with single hop at the source side;

[0208] - the multi-hop indication indicates that the target side path is indirectly connected with multiple hops.

[0209] Optionally, in case that the UE meets at least one of the above conditions, the UE indicates the upper layer to trigger the establishment of the PC5 unicast link between the UE and the target side U2N Relay UE. Optionally, the target side U2N Relay UE is indicated by the first entry in a target side Relay UE list, or is indicated by a target side intermediate U2N Relay UE identity, or is indicated by the first entry in a target side intermediate U2N Relay UE list.

[0210] Alternatively, optionally, the UE judges at least one of the following conditions:

[0211] - the UE is (or: is being) an intermediate U2N Relay UE (or U2N Relay UE) at the source side;

[0212] - the RRC message contains a Sidelink Path Switching Configuration;

[0213] - the UE is directly connected to the network at the source side;

[0214] - the UE is indirectly connected to the network with single hop at the source side;

[0215] - the multi-hop indication indicates that the target side path is indirectly connected with multiple hops.

[0216] Optionally, the PC5 unicast link between the UE and the target side U2N Relay UE is established upon the upper layer trigger, in case that the UE satisfies at least one of the above conditions. Wherein, optionally, the target side U2N Relay UE is indicated by the target side Relay UE identity, or the first entry in the target side Relay UE list, or the target side intermediate U2N Relay UE identity, or the first entry in the target side intermediate U2N Relay UE list, or the target side last U2N Relay UE identity.

[0217] FIG. 5 is a schematic diagram of a method three performed by a UE according to one or more embodiments. The UE can perform one or more steps in FIG. 5. FIG. 5 includes steps S301-S302.

[0218] FIG. 5 is for the path switching scenario of multi-hop indirect connection to direct connection, or the path switching scenario of multi-hop indirect connection to single-hop indirect connection.

[0219] Optionally, in step S301, the UE receives a dedicated RRC message (e.g., RRCReconfiguration) sent by the network. Optionally, the RRC message contains reconfigurationWithSync, and / or SidelinkPathSwitchConfig. Optionally, the SidelinkPathSwitchConfig is contained in the reconfigurationWithSync.

[0220] Optionally, in step S302, the UE triggers the connection release with the source side U2N Relay UE.

[0221] Optionally, the UE judges at least one of the following conditions:

[0222] - the UE is (or: is being) a L2 U2N Remote UE at the source side;

[0223] - the RRC message contains SidelinkPathSwitchConfig;

[0224] - the UE is multi-hop indirectly connected to the network at the source side;

[0225] - the multi-hop indication indicates that the target path is single-hop indirect connection.

[0226] Optionally, in case that the UE satisfies at least one of the above conditions, the UE performs at least one of the following operations:

[0227] - indicates the upper layer to trigger the PC5 unicast link release between the UE and the connected service U2N Relay UE at the source side;

[0228] - indicating upper layer to trigger the UE and the (source side) first U2N Relay UE between the PC5 unicast link release;

[0229] - indicating upper layer to trigger the UE and the (source side) connected U2N Relay UE (or intermediate U2N Relay UE) between the PC5 unicast link release;

[0230] - indicating upper layer to trigger the UE and the (source side) next hop UE between the PC5 unicast link release.

[0231] Alternatively, the UE judges at least one of the following conditions:

[0232] - the UE is (or: is acting as) an intermediate U2N Relay UE (or U2N Relay UE, or first U2N Relay UE, or second U2N Relay UE) on the source side;

[0233] - the RRC message contains a Sidelink Path Switch configuration;

[0234] - the UE is indirectly connected to the network by multiple hops on the source side;

[0235] - the multi-hop indication indicates that the target path is a single-hop indirect connection.

[0236] Optionally, in the case where the UE meets at least one of the above conditions, the UE performs at least one of the following operations:

[0237] - indicating upper layer to trigger the UE and the (source side) connected service U2N Relay UE between the PC5 unicast link release;

[0238] - indicating upper layer to trigger the UE and the (source side) second U2N Relay UE between the PC5 unicast link release;

[0239] - indicating upper layer to trigger the UE and the (source side) connected last U2N Relay UE between the PC5 unicast link release;

[0240] - indicating upper layer to trigger the UE and the (source side) connected U2N Relay UE (or intermediate U2N Relay UE) between the PC5 unicast link release;

[0241] - indicating upper layer to trigger the UE and the (source side) next hop UE between the PC5 unicast link release.

[0242] FIG. 6 is a schematic diagram of a method four performed by a UE according to one or more embodiments. The UE can perform one or more steps in FIG. 6. FIG. 6 includes steps S401-S403.

[0243] In multi-hop U2N relay architecture, U2N Remote UE and network are connected through Relay UE, U2N Remote UE in RRC_IDLE / RRC_INACTIVE state needs to inform the last U2N Relay UE which system information it requests and its paging related information, the last U2N Relay UE and intermediate U2N Relay UE forward the system information and paging information of the network to the U2N Remote UE.

[0244] Optionally, the UE is a L2 U2N Remote UE, and / or the UE has a capability of a L2 U2N Remote UE, and / or the UE is operating as a L2 U2N Remote UE, and / or the UE is a UE supporting L2 U2N Remote UE operation. Optionally, steps S401-S403 and the judgment and operation in each step are optionally performed in the case of judging that the UE is a UE with the above characteristics.

[0245] Optionally, in step S401, when any information in Remote UE Information Sidelink message changes, the UE sends the Remote UE Information Sidelink message to the connected intermediate U2N Relay UE (or the connected first U2N Relay UE, or the connected U2N Relay UE, or the next hop UE). Optionally, the Remote UE Information Sidelink message is a PC5-RRC message used to request SIB(s), or provide paging related information, or provide remote UE information.

[0246] Optionally, in step S402, the UE sets the content of the Remote UE Information Sidelink message.

[0247] Optionally, the Remote UE Information Sidelink message contains at least one of the following information:

[0248] - the identity of the U2N Remote UE (the identity is, for example, an L2 ID, or a source L2 ID, or a target L2 ID);

[0249] - an identity of the U2N Remote UE (identity e.g. L2 ID, or source L2 ID, or target L2 ID);

[0250] The UE sets at least one of the above information.

[0251] The identity of the U2N Remote UE is used to indicate the U2N Remote UE (i.e. the UE), and the identity of the last U2N Relay UE is used to indicate the last U2N Relay UE.

[0252] Optionally, in step S403, the UE submits the RemoteUEInformationSidelink message to lower layer(s) for transmission.

[0253] Figure 7 is a schematic diagram of a method five performed by a UE according to one or more embodiments. The UE can perform one or more steps in Figure 7. Figure 7 comprises steps S501-S503.

[0254] Optionally, the UE is a L2 U2N Relay UE capable UE, the UE is an intermediate U2N Relay UE capable UE, and / or the UE is an intermediate U2N Relay UE, and / or the UE is operating as an intermediate U2N Relay UE, and / or the UE is a UE supporting intermediate U2N Relay UE operation, and / or the UE is a first U2N Relay UE, and / or the UE is a second U2N Relay UE. Optionally, steps S501-S503 and the judgements and operations in the steps are optionally performed in the case where the UE is a UE having the above characteristics.

[0255] Optionally, in step S501, the UE receives a PC5-RRC message (e.g. RemoteUEInformationSidelink message). Optionally, the PC5-RRC message is received from a L2 U2N Remote UE, or from an intermediate U2N Relay UE, or from a first U2N Relay UE, or from a second U2N Relay UE, or from a previous hop UE. Optionally, the PC5-RRC message contains at least one of the following information:

[0256] - an identity of the U2N Remote UE (identity e.g. L2 ID, or source L2 ID, or target L2 ID);

[0257] - an identity of the last U2N Relay UE (identity e.g. L2 ID, or source L2 ID, or target L2 ID).

[0258] The identity of the U2N Remote UE is used to indicate the U2N Remote UE (i.e. the UE) and the identity of the last U2N Relay UE is used to indicate the last U2N Relay UE.

[0259] Optionally, in step S502, the UE initiates a procedure to forward / send the PC5-RRC message (e.g. RemoteUEInformationSidelink message).

[0260] Optionally, the UE performs at least one of the following operations:

[0261] - forwards / sends the PC5-RRC message to the last U2N Relay UE;

[0262] - forwards / sends the PC5-RRC message to an intermediate U2N Relay UE.

[0263] - forwards / sends the PC5-RRC message to the next hop UE;

[0264] - forwards / sends the PC5-RRC message to the next hop UE associated with the U2N Remote UE.

[0265] wherein, optionally, the last U2N Relay UE is the last U2N Relay UE indicated in the PC5-RRC message received by the UE, in particular the last U2N Relay UE indicated by the identity of the last U2N Relay UE in the PC5-RRC message received.

[0266] wherein, optionally, the intermediate U2N Relay UE refers to an intermediate U2N Relay UE comprising at least one of the following features:

[0267] - is an intermediate U2N Relay UE directly connected to the UE;

[0268] - is the next hop intermediate U2N Relay UE (e.g. for the first U2N Reley UE, the next intermediate U2N Relay UE is the second U2N Reley UE);

[0269] - is an intermediate U2N Relay UE associated with the U2N Remote UE.

[0270] Among them, optionally, the U2N Remote UE is the U2N Remote UE indicated in the PC5-RRC message received by the UE, in particular the U2N Remote UE indicated by the identity of the U2N Remote UE in the received PC5-RRC message.

[0271] Optionally, the PC5-RRC message (for example, RemoteUEInformationSidelink message) forwarded / sent by the UE contains at least one of the following information:

[0272] -Identity of the U2N Remote UE (identity, for example: L2 ID, or source L2 ID, or target L2 ID);

[0273] -Identity of the last U2N Relay UE (identity, for example: L2 ID, or source L2 ID, or target L2 ID);

[0274] -Message forwarding container.

[0275] Among them, optionally, the identity of the U2N Remote UE is one or more, and if it is more than one, it can be a list of identities of the U2N Remote UE. The identity of the U2N Remote UE is used to indicate the U2N Remote UE, and the identity of the last U2N Relay UE is used to indicate the last U2N Relay UE.

[0276] The UE sets at least one of the above information. Alternatively, if the UE initiates PC5-RRC message transmission is due to receiving the PC5-RRC message sent by the U2N Remote UE (or intermediate U2N Relay UE, or first U2N Relay UE, or second U2N Relay UE, or last hop UE), the UE sets at least one of the above information.

[0277] Optionally, when the UE sets at least one of the above information, it performs at least one of the following operations:

[0278] -Set the identity of the U2N Remote UE as the identity of the U2N Remote UE carried in the PC5-RRC message received in step S501;

[0279] -Set the identity of the last U2N Relay UE as the identity of the last U2N Relay UE carried in the PC5-RRC message received in step S501;

[0280] - the PC5-RRC message received in step S501 is packed in a message forwarding container.

[0281] Optionally, in step S503, the UE submits the PC5-RRC message to lower layer(s) for transmission.

[0282] Figure 8 is a schematic diagram of a method six performed by a UE according to one or more embodiments. The UE can perform one or more steps in Figure 8. Figure 8 includes steps S601-S602.

[0283] Optionally, the UE is a last U2N Relay UE capable, and / or the UE is a last U2N Relay UE, and / or the UE is operating as a last U2N Relay UE, and / or the UE is a UE supporting last U2N Relay UE operation. Optionally, steps S601-S602 and the judgements and operations in the steps are optionally performed in the case that the UE is a UE having the above characteristics.

[0284] Optionally, in step S601, the UE and an intermediate U2N Relay UE (or next hop UE) establish a PC5-RRC connection.

[0285] Optionally, in step S602, when the PC5-RRC connection between the UE and the intermediate U2N Relay UE (or next hop UE) is established, the UE performs at least one of the following operations:

[0286] - establishes an SRAP entity if the SRAP entity has not been established;

[0287] - applies the protocol specified RLC configuration of SL-RLC0;

[0288] - applies the RLC default configuration of SL-RLC1 if the UE is in RRC_IDLE state or RRC_INACTIVE state.

[0289] Optionally, when the PC5-RRC connection between the UE and the intermediate U2N Relay UE (or next hop UE) is established, the intermediate U2N Relay UE (or next hop UE) performs at least one of the following operations:

[0290] - establishes an SRAP entity if the SRAP entity has not been established;

[0291] - applies the protocol specified RLC configuration of SL-RLC0;

[0292] - if the intermediate U2N Relay UE (or next hop UE) is in RRC_IDLE state or RRC_INACTIVE state, apply the RLC default configuration of SL-RLC1.

[0293] wherein optionally the SL-RLC0 is for SRB0 of a U2N Remote UE, and / or the SL-RLC0 is for SRB0 of the UE. Optionally the SL-RLC1 is for SRB1 of a U2N Remote UE, and / or the SL-RLC1 is for SRB1 of the UE.

[0294] Figure 9 is a schematic diagram of a method seven performed by a UE according to one or more embodiments. The UE can perform one or more steps in Figure 9. Figure 9 includes steps S701-S702.

[0295] Optionally, the UE is L2 U2N Relay UE capable, and / or the UE is intermediate U2N Relay UE capable, and / or the UE is an intermediate U2N Relay UE, and / or the UE is operating as an intermediate U2N Relay UE, and / or the UE is a UE supporting intermediate U2N Relay UE operation, and / or the UE is a first U2N Relay UE, and / or the UE is a second U2N Relay UE. Optionally, in the case where the UE is determined to be a UE with the above characteristics, steps S701-S702 and the determinations and operations in the steps are optionally performed.

[0296] Optionally, at step S701, the UE initiates a RRC connection resume procedure, or the UE initiates a RRC connection establishment procedure.

[0297] Optionally, at step S702, when the UE initiates a RRC connection resume procedure, or when the UE initiates a RRC connection establishment procedure, the UE performs at least one of the following:

[0298] - if the SRAP entity has not been established, establish the SRAP entity;

[0299] - apply the protocol specified RLC configuration of SL-RLC0;

[0300] - if the UE is in RRC_IDLE state or RRC_INACTIVE state, apply the RLC default configuration of SL-RLC1.

[0301] Optionally, the SL-RLC0 is for SRB0 of a U2N Remote UE, and / or the SL-RLC0 is for SRB0 of the UE. Optionally, the SL-RLC1 is for SRB1 of a U2N Remote UE, and / or the SL-RLC1 is for SRB1 of the UE.

[0302] Figure 10 is a schematic diagram of a method eight performed by a UE according to one or more embodiments. The UE can perform one or more steps in Figure 10. Figure 10 includes steps S801-S802.

[0303] The UE in RRC CONNECTED state can receive network configuration, the network configures the UE with L2 U2N Relay UE(s) connected to it, mainly including the configuration of SRAP.

[0304] Optionally, in step S801, the UE receives the L2 Relay UE configuration (and / or intermediate U2N Relay UE configuration, and / or next hop UE configuration) sent by the network.

[0305] The L2 Relay UE configuration (and / or the intermediate U2N Relay UE configuration, and / or the next hop UE configuration) is contained in a dedicated RRC message (such as RRC Reconfiguration RRCReconfiguration message, or RRC Setup RRCSetup message, or RRC Resume RRCResume message, or RRC Reestablishment RRCRestablishment message), or in a system message, or in a MAC CE, or in a pre-configuration. Optionally, the L2 Relay UE configuration (and / or the intermediate U2N Relay UE configuration, and / or the next hop UE configuration) is used for the relevant configuration of the L2 Relay UE and / or intermediate U2N Relay UE and / or next hop UE used by the UE for L2 U2N relay operation.

[0306] Optionally, the L2 Relay UE configuration (and / or the intermediate U2N Relay UE configuration, and / or the next hop UE configuration) contains at least one of the following information:

[0307] - Intermediate U2N Relay UE addition modification list;

[0308] - Intermediate U2N Relay UE release list;

[0309] - Last U2N Relay UE addition modification list;

[0310] - first U2N Relay UE addition / modification list;

[0311] - second U2N Relay UE addition / modification list;

[0312] - previous hop (intermediate) U2N Relay UE addition / modification list;

[0313] - next hop (intermediate) U2N Relay UE addition / modification list;

[0314] - previous hop UE addition / modification list;

[0315] - next hop UE addition / modification list.

[0316] Optionally, in step S802, the UE performs configuration operation(s) according to the L2 Relay UE configuration (and / or intermediate U2N Relay UE configuration, and / or next hop UE configuration).

[0317] Optionally, in case the UE is (or: is acting as) a U2N Remote UE, the UE performs at least one of the following operations:

[0318] - if the L2 Relay UE configuration (and / or intermediate U2N Relay UE configuration, and / or next hop UE configuration) contains an intermediate U2N Relay UE addition / modification list, the UE performs addition / modification operation(s) of an intermediate U2N Relay UE;

[0319] - if the L2 Relay UE configuration (and / or intermediate U2N Relay UE configuration, and / or next hop UE configuration) contains a first U2N Relay UE addition / modification list, the UE performs addition / modification operation(s) of a first U2N Relay UE.

[0320] Optionally, in case the UE is (or: is acting as) a last U2N Relay UE, the UE performs at least one of the following operations:

[0321] - if the L2 Relay UE configuration (and / or intermediate U2N Relay UE configuration, and / or next hop UE configuration) contains an intermediate U2N Relay UE addition / modification list, the UE performs addition / modification operation(s) of an intermediate U2N Relay UE;

[0322] - if the L2 Relay UE configuration (and / or intermediate U2N Relay UE configuration, and / or next-hop UE configuration) contains a first U2N Relay UE addition / modification list, the UE performs addition / modification operation of the first U2N Relay UE;

[0323] - if the L2 Relay UE configuration (and / or intermediate U2N Relay UE configuration, and / or next-hop UE configuration) contains a second U2N Relay UE addition / modification list, the UE performs addition / modification operation of the second U2N Relay UE.

[0324] Optionally, in case the UE is (or: is acting as) an intermediate U2N Relay UE (or a first U2N Relay UE, or a second U2N Relay UE), the UE performs at least one of the following operations:

[0325] - if the L2 Relay UE configuration (and / or intermediate U2N Relay UE configuration, and / or next-hop UE configuration) contains an upper-hop (intermediate) U2N Relay UE addition / modification list, the UE performs addition / modification operation of the upper-hop (intermediate) U2N Relay UE;

[0326] - if the L2 Relay UE configuration (and / or intermediate U2N Relay UE configuration, and / or next-hop UE configuration) contains a lower-hop (intermediate) U2N Relay UE addition / modification list, the UE performs addition / modification operation of the lower-hop (intermediate) U2N Relay UE;

[0327] - if the L2 Relay UE configuration (and / or intermediate U2N Relay UE configuration, and / or next-hop UE configuration) contains a last U2N Relay UE addition / modification list, the UE performs addition / modification operation of the last U2N Relay UE.

[0328] wherein, in case the UE is (or: is acting as) an intermediate U2N Relay UE, if the UE is a first U2N Relay UE, the lower-hop (intermediate) U2N Relay UE (or next-hop UE) is a second U2N Relay UE; if the UE is a second U2N Relay UE, the upper-hop (intermediate) U2N Relay UE (or upper-hop UE) is a first U2N Relay UE.

[0329] Unless otherwise specified, the order of judgment, operation and execution in each step in the embodiments is irrelevant, i.e. the order of judgment and operation can be changed.

[0330] FIG. 11 is a brief structural block diagram of a user equipment UE to which the present application is applied. As shown in FIG. 11, the user equipment UE 1100 includes a processor 1101 and a memory 1102. The processor 1101 can include, for example, a microprocessor, a microcontroller, an embedded processor, etc. The memory 1102 can include, for example, a volatile memory (such as a random access memory (RAM)), a hard disk drive (HDD), a non-volatile memory (such as a flash memory), or other storage devices. The memory 1102 stores program instructions therein. The program instructions, when executed by the processor 1101, can perform the above-described method executed by the user equipment in detail.

[0331] A program running on the apparatus according to the present application can be a program for causing a computer to implement the functions of the embodiments of the present application by controlling a central processing unit (CPU). The program or information processed by the program can be temporarily stored in a volatile memory (such as a random access memory (RAM)), a hard disk drive (HDD), a non-volatile memory (such as a flash memory), or other storage systems.

[0332] A program for implementing the functions of the embodiments of the present application can be recorded on a computer-readable recording medium. The corresponding functions can be implemented by causing a computer system to read the program recorded on the recording medium and execute the program. The so-called "computer system" herein can be a computer system embedded in the apparatus and can include an operating system or hardware (such as a peripheral device). The "computer-readable recording medium" can be a semiconductor recording medium, an optical recording medium, a magnetic recording medium, a short-time dynamic storage program recording medium, or any other computer-readable recording medium.

[0333] The various features or functional modules of the apparatus used in the above-described embodiments can be implemented or executed by a circuit (for example, a single-chip or multi-chip integrated circuit). The circuit designed to perform the functions described in the specification can include a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gates or transistor logic, discrete hardware components, or any combination thereof. The general-purpose processor can be a microprocessor, or any existing processor, controller, microcontroller, or state machine. The above-mentioned circuit can be a digital circuit, or an analog circuit. In the case of the emergence of new integrated circuit technologies that replace existing integrated circuit technologies due to advances in semiconductor technologies, one or more embodiments of the present application can also be implemented using these new integrated circuit technologies.

[0334] Furthermore, the present application is not limited to the above-described embodiments. Although various examples of the embodiments have been described, the present application is not limited thereto. Fixed or non-mobile electronic devices installed indoors or outdoors can be used as terminal devices or communication devices, such as AV devices, kitchen devices, cleaning devices, air conditioners, office devices, automatic vending machines, and other home appliances.

[0335] As described above, the embodiments of the present application have been described in detail with reference to the accompanying drawings. However, the specific configuration is not limited to the above-described embodiments, and the present application includes any design modification without departing from the gist of the present application. In addition, various modifications can be made to the present application within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in the different embodiments are also included in the technical scope of the present application. Furthermore, components described in the above-described embodiments having the same effect can be substituted for each other.

Claims

1. A method performed by a user equipment (UE), comprising: receiving a first remote UE sidelink information message, and sending a second remote UE sidelink information message to a second UE if the first remote UE sidelink information message is received from a first UE, the first UE is a UE closer to a remote UE connected to the intermediate relay UE, and the second UE is a UE closer to a network connected to the intermediate relay UE. 2.A method performed by a user equipment (UE), comprising: receiving a measurement configuration sent by a network; performing a measurement associated with a connected relay UE or a measurement associated with a next hop UE if the UE is configured with the measurement configuration; and reporting a measurement report to the network, the measurement report containing a measurement result of the connected relay UE or the next hop UE. 3.The method of claim 2, wherein in the step of reporting the measurement report to the network, the UE performs at least one of the following operations: setting a connected relay UE identity indicating an identity of a relay UE connected to the UE; setting a next hop UE identity indicating an identity of a next hop UE; setting a measurement result containing a SL-RSRP or a SD-RSRP of the relay UE connected to the UE; and setting a measurement result containing a SL-RSRP or a SD-RSRP of the next hop UE. 4.A method performed by a user equipment (UE), comprising: receiving a dedicated RRC message sent by a network, the RRC message containing a synchronization reconfiguration and / or a sidelink path switch configuration; and triggering a connection establishment with a target side relay UE according to the received RRC message. 5.The method of claim 4, wherein the sidelink path switch configuration contains at least one of the following information: a multi-hop indication; a target side relay UE identity; a target side relay UE list; a target side last relay UE identity; a target side intermediate relay UE identity; and a target side intermediate relay UE list. 6.The method of claim 4, wherein in the step of triggering the connection establishment with the target side relay UE, the UE judges at least one of the following conditions: the UE is a remote UE or is acting as a remote UE at a source side; the RRC message contains a sidelink path switch configuration; the UE is directly connected to a network at the source side; the UE is single-hop indirectly connected to the network at the source side; and a multi-hop indication indicates that a target side path is a multi-hop indirect connection, if the UE meets at least one of the above conditions, indicating a higher layer to trigger a PC5 unicast link establishment between the UE and the target side relay UE. 7.The method of claim 4, wherein in the step of triggering the connection establishment with the target side relay UE, the UE judges at least one of the following conditions: the UE is an intermediate relay UE or is acting as an intermediate relay UE at a source side; the RRC message contains a sidelink path switch configuration; the UE is directly connected to a network at the source side; the UE is single-hop indirectly connected to the network at the source side; and a multi-hop indication indicates that a target side path is a multi-hop indirect connection, if the UE meets at least one of the above conditions, indicating a higher layer to trigger a PC5 unicast link establishment between the UE and the target side relay UE. - the multi-hop indication indicates that the target side path is a multi-hop indirect connection, in case the UE fulfills at least one of the above conditions, the UE indicates to the upper layer to trigger the PC5 unicast link release between the UE and the source side connected relay UE.

8. A method performed by a user equipment (UE), comprising: receiving a dedicated RRC message sent by a network, the RRC message containing a synchronization reconfiguration and / or a sidelink path switch configuration; and triggering a connection release with a source side relay UE according to the received RRC message.

9. The method of claim 8, wherein, in the step of triggering the connection release with the source side relay UE, the UE judges at least one of the following conditions: - the UE is a remote UE at the source side or is acting as a remote UE; - the RRC message contains a sidelink path switch configuration; - the UE is a multi-hop indirect connection to the network at the source side; and - the multi-hop indication indicates that the target path is a single-hop indirect connection, in case the UE fulfills at least one of the above conditions, the UE performs at least one of the following operations: - indicating to the upper layer to trigger a PC5 unicast link release between the UE and a serving relay UE connected at the source side; - indicating to the upper layer to trigger a PC5 unicast link release between the UE and a first relay UE at the source side; - indicating to the upper layer to trigger a PC5 unicast link release between the UE and a relay UE or an intermediate relay UE connected at the source side; and - indicating to the upper layer to trigger a PC5 unicast link release between the UE and a next hop UE at the source side.

10. A user equipment (UE), comprising: a processor; and a memory storing instructions, wherein the instructions, when executed by the processor, perform the method of any one of claims 1 to 9.

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