Method executed by user device and user device

Abstract

Provided in the present invention are a method executed by a user device and a user device. The method comprises: a UE receives a message containing indication information, the indication information being used for indicating a change in a sidelink communication connection or a sidelink communication bearer corresponding to a certain target; according to the indication information, the UE triggers a process corresponding to the change; and the UE determines in the process the type of the sidelink communication connection or the sidelink communication bearer and / or an association condition with an RLC channel or an RLC entity, and correspondingly processes an RLC layer and / or an MAC layer according to the type of the sidelink communication connection or the sidelink communication bearer and / or the association condition with the RLC channel or the RLC entity. Therefore, when end-to-end connection and bearers between remote UEs change, the UEs can correctly process an RLC layer and an MAC layer between a remote UE and a relay UE, thereby avoiding the occurrence of anomaly, and accordingly reducing the impact on the service performance.

Description

Method performed by user equipment and user equipment Technical Field

[0001] The present invention relates to the field of wireless communication technology, and more particularly, to a communication method based on a UE-to-UE sideline communication relay architecture performed by a user equipment and a corresponding user equipment. Background Art

[0002] In March 2020, at the RAN#91 plenary meeting, a work item for NR sidelink relaying for Release 17 was proposed and approved (see non-patent document: RP-210904 New Study Item on NR Sidelink Relaying). The latest version of this work item can be found in non-patent document: RP-212601 reivised WID NR sidelink relay. One of the goals of this work item is to standardize sidelink control plane procedures, such as RRC connection management, reception of system messages, and reception of paging. The work item also aims to standardize the selection and reselection procedures for sidelink relay UEs.

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

[0004] When the end-to-end connection and bearer between the remote UEs change, how to handle the RLC layer and MAC layer between the remote UE and the relay UE is a problem that needs to be solved. Summary of the Invention

[0005] In order to solve at least part of the above problems, the present invention provides a method performed by a user equipment and the user equipment, wherein the UE processes the RLC layer and the MAC layer between the remote UE and the relay UE when the end-to-end connection and the bearer change.

[0006] According to a first aspect of the present invention, a method performed by a user equipment (UE) is provided, comprising: the UE receiving a message containing indication information, the indication information being used to indicate a change in a sideline communication connection or a sideline communication bearer corresponding to a certain target; the UE triggering a process corresponding to the change according to the indication information; the UE determining the type of the sideline communication connection or the sideline communication bearer and / or its association status with an RLC channel or an RLC entity in the process, and performing corresponding processing on the RLC layer and / or the MAC layer according to the type of the sideline communication connection or the sideline communication bearer and / or its association status with an RLC channel or an RLC entity.

[0007] According to a second aspect of the present invention, a user equipment is provided, comprising: a processor; and a memory storing instructions, wherein the instructions execute the above method when executed by the processor.

[0008] Effects of the Invention

[0009] According to the present invention, when the end-to-end connection and bearer between remote UEs change, the UE can correctly process the RLC layer and MAC layer between the remote UE and the relay UE, avoiding abnormalities and thus reducing the impact on service performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG1 is a schematic diagram showing relay forwarding between remote UEs via a relay UE.

[0011] FIG2 is a schematic diagram illustrating control plane protocol stacks of a remote UE and a relay UE in an L2 U2U sidelink communication relay architecture.

[0012] FIG3 is a schematic diagram illustrating user plane protocol stacks of a remote UE and a relay UE in an L2 U2U sidelink communication relay architecture.

[0013] FIG4 is a flow chart of a method executed by a user equipment according to the present invention.

[0014] FIG5 is a flowchart of a method executed by a user equipment according to embodiment 1 of the present invention.

[0015] FIG6 is a flowchart of a method executed by a user equipment according to embodiment 2 of the present invention.

[0016] FIG7 is a flowchart of a method executed by a user equipment according to embodiment 3 of the present invention.

[0017] FIG8 is a flowchart of a method executed by a user equipment according to embodiment 4 of the present invention.

[0018] FIG9 is a flowchart of a method executed by a user equipment according to embodiment 5 of the present invention.

[0019] FIG10 is a flowchart of a method executed by a user equipment according to embodiment 6 of the present invention.

[0020] FIG11 is a flowchart of a method executed by a user equipment according to Embodiment 7 of the present invention.

[0021] FIG12 is a simplified structural block diagram of a user equipment UE according to the present invention. DETAILED DESCRIPTION

[0022] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the present invention is not limited to the specific embodiments described below. In addition, for the sake of simplicity, detailed descriptions of known technologies that are not directly related to the present invention are omitted to prevent confusion in understanding the present invention.

[0023] The following describes some of the terms involved in this invention. The specific meanings of the terms can be found in the latest 3GPP standards.

[0024] UE: User Equipment

[0025] NR: New Radio, a new generation of wireless technology

[0026] PHY: physical layer, physical layer

[0027] MAC: Medium Access Control, multimedia access control

[0028] RLC: Radio Link Control

[0029] SDAP: Service Data Adaptation Protocol

[0030] PDCP: Packet Data Convergence Protocol, Packet Data Convergence Protocol

[0031] SRAP: Sidelink Relay Adaptation Protocol, Sidelink Relay Adaptation Protocol

[0032] RRC: Radio Resource Control

[0033] RRC_CONNECTED: RRC connected state

[0034] RRC_INACTIVE: RRC inactive state

[0035] RRC_IDLE: RRC idle state

[0036] RAN: Radio Access Network

[0037] NG-RAN: Next-generation radio access network

[0038] gNB: the next Generation Node B, next generation base station

[0039] Sidelink: Sidelink communication, sidelink

[0040] SL: Sidelink, side communication, side link

[0041] SCI: Sidelink Control Information, sidelink communication control information

[0042] AS: Access Stratum, access layer

[0043] IE: Information Element

[0044] CE: Control Element

[0045] MIB: Master Information Block

[0046] SIB: System Information Block

[0047] DCI: Downlink Control Information, downlink control information

[0048] RB: radio bearer

[0049] DRB: Data Radio Bearer

[0050] SRB: Signaling Radio Bearer

[0051] Uu: air interface

[0052] ProSe:Proximity based Services:Proximity services

[0053] V2X: Vehicle-to-Everything

[0054] NAS: Non-Access-Stratum

[0055] PC5-S: PC5 signalling, PC5 signaling

[0056] SL-SRB: Sidelink Signalling Radio Bearer

[0057] SL-DRB: Sidelink Data Radio Bearer, sidelink communication data radio bearer

[0058] U2U: UE-to-UE, UE to UE

[0059] U2N: UE-to-Network

[0060] L2: Layer 2, layer 2 architecture

[0061] RSRP: Reference Signal Received Power

[0062] SL-RSRP: Sidelink RSRP, sidelink communication reference signal received power

[0063] SD-RSRP: sidelink discovery RSRP, sidelink communication discovery message reference signal received power

[0064] SpCell: Special Cell, including PCell and PSCell

[0065] PCell: Primary Cell

[0066] PSCell: Primary SCG Cell, SCG main cell

[0067] L2-ID: Layer-2 ID (identity), layer 2 identification

[0068] 3GPP: 3rd Generation Partnership Project

[0069] In the present invention, network (network or NW), base station (base station or gNB or eNB) and RAN are used interchangeably. The network may be a Long Term Evolution LTE network, a New Radio Access Technology (New RAT, 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 invention may 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 may also be a cell under any of the above-mentioned types of base stations. Unless otherwise specified, the cell, beam, and transmission point (TRP) may be interchangeable, and the base station may also be a central unit (gNB-Central Unit, gNB-CU) or a distributed unit (gNB-Distributed Unit, gNB-DU) constituting the base station.

[0070] In the present invention, the user equipment UE may refer to the NR device supporting the NR Sidelink relay function described in the background technology, or the NR device supporting the L2 U2U relay function, or may refer to other types of NR devices or LTE devices.

[0071] In the present invention, sidelink, SL and PC5 can be used interchangeably.

[0072] In the present invention, unless otherwise specified, "Relay UE", "U2U Relay UE" and "L2 U2U Relay UE" can be used interchangeably. Unless otherwise specified, "Remote UE", "U2U Remote UE" and "L2 U2U Remote UE" can be used interchangeably.

[0073] In the present invention, "change" and "update" can be used interchangeably.

[0074] In the present invention, "configure", "set" and "present" can be used interchangeably.

[0075] In the present invention, “used,” “available,” “active,” “applied,” “performed,” and “enabled” may be used interchangeably.

[0076] In the present invention, “use,” “make available,” “apply,” “implement,” “enable,” “activate,” “perform,” “do,” etc. may be used interchangeably.

[0077] In the present invention, "feedback", "submit", "report", "send", "transmit or transport", "inform", "indicate" and "provide" can be used interchangeably.

[0078] In the present invention, "trigger" and "initiate" can be used interchangeably.

[0079] In the present invention, "associate", "correspond" and "map" can be used interchangeably.

[0080] In the present invention, the upper layer may refer to the ProSe layer, or the V2X layer, or the NAS layer, or the PC5-S protocol layer, or a layer above the RRC layer. In the present invention, the ProSe layer, the V2X layer, the NAS layer, and the PC5-S protocol layer may be used interchangeably.

[0081] In the present invention, "channel" may refer to one channel or multiple channels.

[0082] In the present invention, "PC5 RLC channel" and "PC5 Relay RLC channel" can be used interchangeably.

[0083] In the present invention, both “first hop” and “second hop” can be modified by “PC5”, that is, “first hop” and “second hop” are both based on the PC5 interface.

[0084] In the present invention, unless otherwise specified, "remote UE" may refer to a source-side remote UE and / or a target-side remote UE. "Target-side remote UE" and "opposite-side remote UE" may be used interchangeably.

[0085] It should be noted that in this specification, two things connected by "and", "or", or "and / or" may represent different ways of expressing the same meaning in different application scenarios. There may be a relationship of inclusion and being included between the two, and they do not necessarily refer to completely different content.

[0086] Hereinafter, a description is given of related technologies of the present invention.

[0087] PC5 interface

[0088] The PC5 interface is used for control and user plane sidelink communication between UEs. For sidelink unicast, a PC5-RRC connection is a logical connection at the AS layer between a source Layer 2 ID and a target Layer 2 ID. The upper layer establishes a PC5 unicast link for sidelink unicast communication. Each established PC5 unicast link corresponds to a corresponding PC5-RRC connection.

[0089] Uu interface

[0090] The Uu interface is the wireless communication interface between the UE and the base station. The UE can communicate with the gNB using NR over the Uu interface.

[0091] L2 Architecture

[0092] The L2 architecture is relative to the L3 architecture. In the L2 architecture, the access layer controls or participates in the selection and reselection of relays, as well as the communication between a UE and the network or another UE through relays. In the L3 architecture, the access layer is largely unaware of the existence of relays, or in other words, relays are transparent to the access layer.

[0093] Figure 1 shows a UE-to-UE relay, with remote UEs on the left and right and a relay UE in the middle. The remote UEs and relay UEs are connected via the PC5 interface. If the two remote UEs are far apart or the communication environment is poor, a relay UE is needed to relay signaling and data between them.

[0094] UE-to-UE relay scenarios include:

[0095] 1) Within coverage: Both remote UEs and the relay UE are within coverage;

[0096] 2) Out of coverage: Both remote UEs and the relay UE are out of coverage;

[0097] 3) Partial coverage: Among the two remote UEs and the relay UE, at least one UE is within the coverage area, and at least one UE is out of the coverage area.

[0098] For the NR Sidelink L2 U2U relay architecture, one of the two remote UEs can be called the source-side remote UE, and the other can be called the target-side remote UE; alternatively, one can be called the remote UE, and the other can be called the peer remote UE. When data / signaling is transmitted between two remote UEs, the remote UE that sends the data / signaling can be called the source-side remote UE, and the UE that receives the data / signaling can be called the target-side remote UE; alternatively, the remote UE that sends the data / signaling can be called the remote UE, and the UE that receives the data / signaling can be called the peer remote UE. The connection / link between the source-side remote UE and the relay UE, or the connection / link with the remote UE as the sender and the relay UE as the receiver, can be called the first hop. The connection / link between the relay UE and the peer remote UE (or target-side remote UE), or the connection / link with the relay UE as the sender and the remote UE as the receiver, can be called the second hop.

[0099] Two remote UEs each establish a PC5-RRC connection with the relay UE. The PC5-RRC connection between the remote UE and the relay UE can be called a per-hop PC5-RRC connection, that is, there are two per-hop PC5-RRC connections: the first hop PC5-RRC connection and the second hop PC5-RRC connection. A PC5-RRC connection is also established between the two remote UEs (via the relay UE), which can be called an end-to-end PC5-RRC connection.

[0100] In the L2 U2U relay architecture, the upper layer establishes a PC5 unicast link between two remote UEs (via the relay UE) (and the AS layer subsequently establishes a PC5-RRC connection), which can be called an end-to-end PC5 unicast link. The upper layer also establishes PC5 unicast links between the two remote UEs and the relay UE. The PC5 unicast link between the remote UE and the relay UE can be called a per-hop PC5 unicast link. When the upper layer releases the PC5 unicast link between the UE and the target UE, it requests the AS layer to release the PC5-RRC connection corresponding to the PC5 unicast link.

[0101] For the Layer 2 (L2) U2U sidelink communication relay architecture, the control plane protocol stacks of the remote UE and the relay UE are shown in FIG2 .

[0102] For the Layer 2 (L2) U2U sidelink communication relay architecture, the user plane protocol stacks of the remote UE and the relay UE are shown in FIG3 .

[0103] In order to carry the control plane signaling between remote UEs, an SL-SRB needs to be established between the remote UE and the peer remote UE. The SL-SRB between the remote UE and the peer remote UE (i.e., between two remote UEs) can be called an end-to-end SL-SRB. In order to carry the control plane signaling between the remote UE and the relay UE, an SL-SRB also needs to be established between the remote UE and the relay UE, which can be called a per-hop SL-SRB. In order to carry the user plane data between remote UEs, an SL-DRB needs to be established between the remote UE and the peer remote UE. The SL-DRB between the remote UE and the peer remote UE (i.e., between two remote UEs) can be called an end-to-end SL-DRB. In order to carry the user plane data between the remote UE and the relay UE, an SL-DRB also needs to be established between the remote UE and the relay UE, which can be called a per-hop SL-DRB.

[0104] A PC5 relay RLC channel (PC5 Relay RLC channel) refers to an RLC channel between a remote UE and a relay UE that transmits signaling and data for L2 U2U relay forwarding via a PC5 interface. In an L2 U2U relay architecture, when two remote UEs are connected through a relay UE, the PC5 relay RLC channel between the remote UE and the relay UE is used to carry data and signaling between the two remote UEs, namely, to carry end-to-end SL-SRBs and end-to-end SL-DRBs. The PC5 relay RLC channel on the first hop is referred to as the first-hop PC5 relay RLC channel (or the source-side PC5 relay RLC channel), and the PC5 relay RLC channel on the second hop is referred to as the second-hop PC5 relay RLC channel (or the target-side PC5 relay RLC channel). The remote UE configures the first-hop PC5 relay RLC channel for the relay UE, and the relay UE configures the second-hop PC5 relay RLC channel for the peer remote UE. Data / signaling sent from one remote UE to multiple peer remote UEs can be multiplexed on the same first-hop PC5 relay RLC channel, and data / signaling from multiple remote UEs sent to one peer remote UE can be multiplexed on the same second-hop PC5 relay RLC channel.

[0105] The PC5-SRAP entity refers to the SRAP entity used for PC5 interface communication. PC5-SRAP is an adaptation layer for the L2 U2U architecture. In the L2 U2U relay architecture, when two remote UEs are connected through a relay UE, the remote UE's PC5-SRAP determines the PC5 relay RLC channel corresponding to uplink data / signaling (data sent by the remote UE to the remote UE), and the PC5 relay RLC channel corresponding to downlink data from the remote UE and forwarded by the relay UE, based on the configured end-to-end bearer to PC5 relay RLC channel mapping. A PC5-SRAP entity also exists in the relay UE for data routing. The remote UE also has a PC5-SRAP, which functions identically to the PC5-SRAP in the source UE. In this document, the terms entity and layer are used interchangeably, for example, SRAP entity or SRAP layer.

[0106] When the sidelink communication RLC entity indicates that a certain target has reached the maximum number of retransmissions, or when the T400 timing for a certain target has expired, or the MAC entity indicates that the HARQ DTX for a certain target has reached the maximum number of retransmissions, or when the sidelink PDCP entity indicates that the SL-SRB2 or SL-SRB3 integrity check for a certain target has failed, the UE considers that a sidelink radio link failure (sidelink radio link failure) for the target has been detected and releases the PC5-RRC connection for the target.

[0107] The present invention discusses how to process the RLC layer and MAC layer between the remote UE and the relay UE when the end-to-end connection and bearer between the remote UEs change. FIG4 is a flowchart of the method performed by the user equipment involved in the present invention. As shown in FIG4 , in the first step, the UE receives a message containing indication information, and the indication information is used to indicate a change in the side communication connection or side communication bearer corresponding to a certain target; in the second step, the UE triggers a process corresponding to the change according to the indication information; in the third step, the UE determines the type of the side communication connection or side communication bearer and / or its association status with the RLC channel or RLC entity in the process, and performs corresponding processing on the RLC layer and / or MAC layer according to the type of the side communication connection or side communication bearer and / or its association status with the RLC channel or RLC entity. Through the present invention, the UE can correctly process the RLC layer and MAC layer between the remote UE and the relay UE, avoid abnormalities, and thus reduce the impact on service performance.

[0108] Hereinafter, several embodiments of the present invention for solving the above problems are described in detail.

[0109] Example 1

[0110] FIG5 is a flowchart of a method executed by a user equipment according to embodiment 1 of the present invention.

[0111] Optionally, in step 101, the UE receives a PC5-RRC message (sent by the opposite UE), such as an RRCReconfigurationSidelink message. Optionally, the RRCReconfigurationSidelink message includes SL-DRB release information, which is used to indicate the release of the SL-DRB.

[0112] Optionally, in step 103, according to the SL-DRB release information in the RRCReconfigurationSidelink message, the UE triggers the SL-DRB release process.

[0113] Optionally, in step 105, the UE processes the RLC layer in the SL-DRB release process.

[0114] Optionally, the UE determines at least one of the following first conditions:

[0115] - the SL-DRB is a per-hop SL-DRB;

[0116] - the SL-DRB is not an end-to-end SL-DRB;

[0117] - No (any) SL-DRB is associated with the RLC channel (or RLC entity) to which the SL-DRB is associated;

[0118] - No (any) other SL-DRB other than the SL-DRB is associated with the RLC channel (or RLC entity) to which the SL-DRB is associated.

[0119] Optionally, when at least one of the first conditions above is met, the UE releases the RLC entity and / or the corresponding logical channel associated with the SL-DRB. Optionally, the UE performs the first condition judgment only when the SL-DRB release is triggered by receiving an RRCReconfigurationSidelink message.

[0120] Optionally, the UE determines at least one of the following second conditions:

[0121] - the SL-DRB is an end-to-end SL-DRB;

[0122] - the SL-DRB is not a per-hop SL-DRB;

[0123] - There is no (any) end-to-end SL-DRB associated with the PC5 Relay RLC channel to which the SL-DRB is associated;

[0124] - No (any) other end-to-end SL-DRB other than the SL-DRB is associated with the PC5 Relay RLC channel associated with the SL-DRB;

[0125] Optionally, if at least one of the second conditions above is met, the UE performs a PC5 Relay RLC channel release (associated with the SL-DRB). Optionally, the PC5 Relay RLC channel release includes: releasing the RLC entity associated with the PC5 Relay RLC channel and / or the corresponding logical channel. Optionally, the UE performs the second condition judgment only when the SL-DRB release is triggered by receiving an RRCReconfigurationSidelink message.

[0126] Optionally, in this embodiment, if the UE is an L2 U2U remote UE, the opposite UE is a peer L2 U2U Remote UE or an L2 U2U Relay UE; if the UE is an L2 U2U Relay UE, the opposite UE is an L2 U2U remote UE or a peer L2 U2U Remote UE.

[0127] Example 2

[0128] FIG6 is a flowchart of a method executed by a user equipment according to embodiment 2 of the present invention.

[0129] Optionally, in step 201, the UE receives SL-DRB configuration information. The SL-DRB configuration information may be included in a system message (e.g., SIB12), or a dedicated RRC message (e.g., an RRCReconfiguration message), or NR sidelink pre-configuration information. Optionally, the SL-DRB configuration information is included in a sidelink communication NR dedicated configuration (sl-ConfigDedicatedNR) information element in the RRCReconfiguration message.

[0130] Optionally, in step 203, the UE determines whether the SL-DRB needs to be released. For example, if the sidelink QoS flow mapped to the SL-DRB configured by the SL-DRB configuration information has no data to be transmitted, it is determined that the SL-DRB needs to be released.

[0131] Optionally, in step 205, the UE sends an RRCReconfigurationSidelink message to the opposite UE, which includes SL-DRB release information for indicating the release of the SL-DRB.

[0132] Optionally, in step 207 , the UE receives an RRCReconfigurationCompleteSidelink message (sent by the opposite UE), triggering a release procedure of the SL-DRB that needs to be released as determined in step 203 .

[0133] Optionally, in step 209, the UE processes the RLC layer in the SL-DRB release process.

[0134] Optionally, the UE judges at least one of the first conditions, and when at least one of the first conditions is met, the UE releases the RLC entity and / or the corresponding logical channel associated with the SL-DRB. Optionally, after receiving the RRCReconfigurationCompleteSidelink message, if the SL-DRB release is triggered by the configuration in the system message (or proprietary RRC message, or NR sidelink pre-configuration information), the UE performs the first condition judgment.

[0135] Optionally, the UE determines at least one of the second conditions, and if at least one of the second conditions is met, the UE executes the release of the PC5 Relay RLC channel (associated with the SL-DRB). Optionally, the release of the PC5 Relay RLC channel includes: releasing the RLC entity and / or the corresponding logical channel associated with the PC5 Relay RLC channel. Optionally, after receiving the RRCReconfigurationCompleteSidelink message, if the SL-DRB release is triggered by the configuration in the system message (or proprietary RRC message, or NR sidelink pre-configuration information), the UE executes the second condition judgment.

[0136] The first condition is the same as the first condition in Example 1, and the second condition is the same as the second condition in Example 1.

[0137] Optionally, in this embodiment, if the UE is an L2 U2U remote UE, the opposite UE is a peer L2 U2U Remote UE or an L2 U2U Relay UE; if the UE is an L2 U2U Relay UE, the opposite UE is an L2 U2U remote UE or a peer L2 U2U Remote UE.

[0138] Example 3

[0139] FIG7 is a flowchart of a method executed by a user equipment according to embodiment 3 of the present invention.

[0140] Optionally, in step 301, if the UE (AS layer or RRC layer) is required by the upper layer(s) to release the PC5-RRC connection for a certain target (UE or layer 2 ID), and / or if the UE detects that the side communication radio link of a certain target fails, the UE releases the PC5-RRC connection corresponding to the target.

[0141] Optionally, in step 303, the UE triggers a release procedure of (one or more) SL-DRBs associated with the PC5-RRC connection.

[0142] Optionally, in step 305, the UE processes the RLC layer in the SL-DRB release process.

[0143] Optionally, for each SL-DRB of the target, the UE determines at least one of the first conditions, and when at least one of the first conditions is met, the UE releases the RLC entity and / or the corresponding logical channel associated with the SL-DRB of the target. Optionally, the UE performs the first condition judgment only when it detects that the sideline communication radio link of the target fails, and / or when the UE is required by the upper layer(s) to release the PCR-RRC connection for the target.

[0144] Optionally, for each SL-DRB of the target, the UE determines at least one of the second conditions, and when at least one of the second conditions is met, the UE performs a PC5 Relay RLC channel release (associated with the SL-DRB of the target). Optionally, the PC5 Relay RLC channel release includes: releasing the RLC entity and / or the corresponding logical channel associated with the PC5 Relay RLC channel. Optionally, the UE performs the second condition judgment only when it detects that the sidelink communication radio link of the target has failed, and / or when the UE is required by the upper layer(s) to release the PCR-RRC connection for the target.

[0145] The first condition is the same as the first condition in Example 1, and the second condition is the same as the second condition in Example 1.

[0146] Optionally, in this embodiment, if the UE is an L2 U2U remote UE, the opposite UE is a peer L2 U2U Remote UE or an L2 U2U Relay UE; if the UE is an L2 U2U Relay UE, the opposite UE is an L2 U2U remote UE or a peer L2 U2U Remote UE.

[0147] Example 4

[0148] FIG8 is a flowchart of a method executed by a user equipment according to embodiment 4 of the present invention.

[0149] Optionally, in step 401, the UE receives a PC5-RRC message (sent by the opposite UE), such as an RRCReconfigurationSidelink message. Optionally, the RRCReconfigurationSidelink message includes SL-DRB modification information, which is used to indicate modification of the SL-DRB.

[0150] Optionally, in step 403, according to the SL-DRB modification information in the RRCReconfigurationSidelink message, the UE triggers the SL-DRB modification process.

[0151] Optionally, in step 405, the UE processes the RLC layer in the SL-DRB modification process.

[0152] Optionally, the UE determines at least one of the first conditions, and if at least one of the first conditions is met, the UE reconfigures the RLC entity associated with the SL-DRB and / or the corresponding logical channel. Optionally, the UE performs the first condition determination only when the SL-DRB modification is triggered by receiving an RRCReconfigurationSidelink message.

[0153] Optionally, the UE determines at least one of the second conditions. If at least one of the second conditions is met, the UE performs a PC5 Relay RLC channel modification (associated with the SL-DRB). Optionally, the PC5 Relay RLC channel modification includes reconfiguring the RLC entity associated with the PC5 Relay RLC channel and the corresponding logical channel. Optionally, the UE performs the second condition determination only if the SL-DRB modification is triggered by receipt of an RRCReconfigurationSidelink message.

[0154] The first condition is the same as the first condition in Example 1, and the second condition is the same as the second condition in Example 1.

[0155] Optionally, in this embodiment, if the UE is an L2 U2U remote UE, the opposite UE is a peer L2 U2U Remote UE or an L2 U2U Relay UE; if the UE is an L2 U2U Relay UE, the opposite UE is an L2 U2U remote UE or a peer L2 U2U Remote UE.

[0156] Example 5

[0157] FIG9 is a flowchart of a method executed by a user equipment according to embodiment 5 of the present invention.

[0158] Optionally, in step 501, the UE receives SL-DRB configuration information. The SL-DRB configuration information may be included in a system message (e.g., SIB12), or a dedicated RRC message (e.g., an RRCReconfiguration message), or NR sidelink pre-configuration information. Optionally, the SL-DRB configuration information is included in a sidelink communication NR dedicated configuration (sl-ConfigDedicatedNR) information element in the RRCReconfiguration message.

[0159] Optionally, in step 503, the UE determines whether the SL-DRB needs to be modified. For example, if any parameters related to the established SL-DRB are modified (for example, modified by SL-DRB configuration information), it is determined that the SL-DRB needs to be modified.

[0160] Optionally, in step 505, the UE sends an RRCReconfigurationSidelink message to the opposite UE, which includes SL-DRB modification information for indicating modification of the SL-DRB.

[0161] Optionally, in step 507 , the UE receives an RRCReconfigurationCompleteSidelink message (sent by the opposite UE), triggering a modification procedure of the SL-DRB that needs to be modified as determined in step 503 .

[0162] Optionally, in step 509, the UE processes the RLC layer in the SL-DRB modification process.

[0163] Optionally, the UE judges at least one of the first conditions, and when at least one of the first conditions is met, the UE reconfigures the RLC entity associated with the SL-DRB and / or the corresponding logical channel. Optionally, after receiving the RRCReconfigurationCompleteSidelink message, the UE performs the first condition judgment only if the SL-DRB modification is triggered by the configuration in the system message (or proprietary RRC message, or NR sidelink pre-configuration information).

[0164] Optionally, the UE determines at least one of the second conditions, and if at least one of the second conditions is met, the UE performs modification of the PC5 Relay RLC channel (associated with the SL-DRB). Optionally, the PC5 Relay RLC channel modification includes: reconfiguring the RLC entity associated with the PC5 Relay RLC channel and / or the corresponding logical channel. Optionally, after receiving the RRCReconfigurationCompleteSidelink message, the UE performs the second condition judgment only if the SL-DRB modification is triggered by the configuration in the system message (or proprietary RRC message, or NR sidelink pre-configuration information).

[0165] The first condition is the same as the first condition in Example 1, and the second condition is the same as the second condition in Example 1.

[0166] Optionally, in this embodiment, if the UE is an L2 U2U remote UE, the opposite UE is a peer L2 U2U Remote UE or an L2 U2U Relay UE; if the UE is an L2 U2U Relay UE, the opposite UE is an L2 U2U remote UE or a peer L2 U2U Remote UE.

[0167] Example 6

[0168] FIG10 is a flowchart of a method executed by a user equipment according to embodiment 6 of the present invention.

[0169] Optionally, in step 601, if the UE (AS layer or RRC layer) is required by the upper layer(s) to release the PC5-RRC connection for a certain target (UE or layer 2 ID), and / or if the UE (AS layer or RRC layer) is required by the upper layer(s) to terminate the PC5-S transmission for a certain target (UE or layer 2 ID), and / or if the UE detects that the side communication radio link of a certain target fails, the UE releases the PC5-RRC connection corresponding to the target.

[0170] Optionally, in step 603, the UE triggers (one or more) SL-SRB release procedures for PC5-RRC messages, and / or triggers (one or more) SL-SRB release procedures for PC5-S messages.

[0171] Optionally, in step 605, the UE processes the RLC layer in the SL-SRB release procedure. Optionally, the SL-SRB is an SL-SRB for a PC5-RRC message, and / or the SL-SRB is an SL-SRB for a PC5-S message.

[0172] Optionally, the UE determines at least one of the following third conditions:

[0173] - the SL-SRB is a per-hop SL-SRB;

[0174] - the SL-SRB is not an end-to-end SL-SRB;

[0175] - No (any) SL-SRB is associated with the RLC channel (or RLC entity) to which the SL-SRB is associated;

[0176] - No (any) other SL-SRB other than the SL-SRB is associated with the RLC channel (or RLC entity) to which the SL-SRB is associated;

[0177] -The PC5-RRC connection is a per-hop PC5-RRC connection;

[0178] - the PC5-RRC connection is not an end-to-end PC5-RRC connection;

[0179] -The PC5-S message is a per-hop PC5-S message;

[0180] - The PC5-S message is not an end-to-end PC5-S message.

[0181] Optionally, when at least one of the third conditions above is met, the UE releases the RLC entity associated with the SL-SRB and / or the corresponding logical channel. Optionally, the UE performs the third condition judgment only when it detects that the sideline communication radio link of the target has failed, and / or when the UE is required by the upper layer(s) to release the PC5-RRC connection for the target, and / or when the UE (AS layer or RRC layer) is required by the upper layer(s) to terminate the PC5-S transmission for a certain target (UE or layer 2 ID).

[0182] Optionally, the UE determines at least one of the following fourth conditions:

[0183] - the SL-SRB is an end-to-end SL-SRB;

[0184] - the SL-SRB is not a per-hop SL-SRB;

[0185] - There is no (any) end-to-end SL-SRB associated with the PC5 RelayRLC channel to which the SL-SRB is associated;

[0186] - No (any) other end-to-end SL-SRB other than the SL-SRB is associated with the PC5 Relay RLC channel associated with the SL-SRB;

[0187] -The PC5-RRC connection is an end-to-end PC5-RRC connection;

[0188] - the PC5-RRC connection is not a per-hop PC5-RRC connection;

[0189] -The PC5-S message is an end-to-end PC5-S message;

[0190] -The PC5-S message is not a per-hop PC5-S message.

[0191] Optionally, when at least one of the fourth conditions above is met, the UE executes the release of the PC5 Relay RLC channel (associated with the SL-SRB). Optionally, the PC5 Relay RLC channel release includes: releasing the RLC entity associated with the PC5 Relay RLC channel and / or the corresponding logical channel. Or, optionally, when executing the PC5 Relay RLC channel release, the UE judges at least one of the fourth conditions, and releases the RLC entity associated with the PC5 Relay RLC channel and / or the corresponding logical channel when at least one of the fourth conditions is met. Optionally, the UE only executes the fourth condition judgment when it detects that the sidelink communication radio link of the target has failed, and / or when the UE is required by the upper layer(s) to release the PC5-RRC connection for the target, and / or when the UE (AS layer or RRC layer) is required by the upper layer(s) to terminate the PC5-S transmission for a certain target (UE or layer 2 ID).

[0192] Optionally, in this embodiment, if the UE is an L2 U2U remote UE, the opposite UE is a peer L2 U2U Remote UE or an L2 U2U Relay UE; if the UE is an L2 U2U Relay UE, the opposite UE is an L2 U2U remote UE or a peer L2 U2U Remote UE.

[0193] Example 7

[0194] FIG11 is a flowchart of a method executed by a user equipment according to Embodiment 7 of the present invention.

[0195] Optionally, in step 701, if the upper layer(s) requires transmission of a PC5-S message for a certain target on the SL-SRB, or if the upper layer(s) indicates establishment of a PC5-RRC connection, the UE adds (or establishes) the SL-SRB.

[0196] Optionally, in step 703, the UE processes the RLC layer in the SL-SRB addition (or establishment) process. Optionally, the SL-SRB is an SL-SRB for PC5-RRC messages and / or an SL-SRB for PC5-S messages.

[0197] Optionally, the UE determines at least one of the third conditions. If at least one of the third conditions is met, the UE establishes the associated RLC entity and / or corresponding logical channel for the SL-SRB used for the PC5-RRC message, and / or the UE establishes the associated RLC entity and / or corresponding logical channel for the SL-SRB used for the PC5-S message. Optionally, the UE determines the third condition only when the upper layer(s) requires the transmission of a PC5-S message for a certain target on the SL-SRB, or when the upper layer(s) indicates the establishment of a PC5-RRC connection.

[0198] Optionally, the UE determines at least one of the fourth conditions. If at least one of the fourth conditions is met, the UE performs PC5 Relay RLC channel establishment, or the UE applies the RLC configuration specified by the SL-U2U-RLC protocol. Optionally, the PC5 Relay RLC channel establishment includes: establishing the RLC entity associated with the PC5 Relay RLC channel and / or the corresponding logical channel. Optionally, the UE determines the fourth condition only when the upper layer(s) requires the transmission of a PC5-S message for a certain target on the SL-SRB, or when the upper layer(s) indicates the establishment of a PC5-RRC connection.

[0199] Among them, the third condition is the same as the third condition in Example 6, and the fourth condition is the same as the fourth condition in Example 6.

[0200] Example 8

[0201] Optionally, if the UE (AS layer or RRC layer) is required by the upper layer(s) to release the PC5-RRC connection for a target (UE or layer 2 ID), and / or if the UE detects that the sidelink communication radio link of a target has failed, and / or if the RRCReconfigurationSidelink message received from a target (UE or layer 2 ID) contains a sidelink communication reset configuration (sl-ResetConfig), the UE processes the MAC layer.

[0202] Optionally, when at least one of the following conditions is met, the processing performed by the UE on the MAC layer is resetting a sidelink specific MAC for the target:

[0203] - except that the (target) PC5-RRC connection is an end-to-end PC5-RRC connection;

[0204] - the (target) PC5-RRC connection is a per-hop PC5-RRC connection;

[0205] - The (target) PC5-RRC connection is not an end-to-end PC5-RRC connection.

[0206] Figure 12 is a simplified block diagram of the user equipment (UE) according to the present invention. As shown in Figure 12, the user equipment (UE) 1200 includes a processor 1201 and a memory 1202. The processor 1201 may include, for example, a microprocessor, a microcontroller, an embedded processor, etc. The memory 1202 may 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 memory. The memory 1202 stores program instructions. When executed by the processor 1201, these instructions may execute the above-described method performed by the user equipment as described in detail in the present invention.

[0207] The program running on the device according to the present invention can be a program that controls the central processing unit (CPU) to enable the computer to implement the functions of the embodiments of the present invention. The program or the 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 memory systems.

[0208] The program for realizing each embodiment of the present invention function can be recorded on a computer-readable recording medium. Can realize corresponding function by making a computer system read the program recorded on the recording medium and executing these programs. So-called "computer system" herein can be the computer system embedded in the device, can include operating system or hardware (such as peripheral device). "Computer-readable recording medium" can be a semiconductor recording medium, an optical recording medium, a magnetic recording medium, a short-term dynamic storage program recording medium or any other recording medium that is computer-readable.

[0209] The various features or functional modules of the devices used in the above embodiments can be implemented or executed by circuits (e.g., single-chip or multi-chip integrated circuits). The circuits designed to perform the functions described in this specification may include a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination of the above devices. The general-purpose processor may be a microprocessor, or any existing processor, controller, microcontroller, or state machine. The above circuits may be digital circuits or analog circuits. In the event that new integrated circuit technologies have emerged to replace existing integrated circuits due to advances in semiconductor technology, one or more embodiments of the present invention may also be implemented using these new integrated circuit technologies.

[0210] Furthermore, the present invention is not limited to the above-described embodiments. Although various examples of the embodiments have been described, the present invention 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 equipment, kitchen equipment, cleaning equipment, air conditioners, office equipment, vending machines, and other household appliances.

[0211] As described above, embodiments of the present invention have been described in detail with reference to the accompanying drawings. However, the specific structure is not limited to the above-described embodiments, and the present invention also includes any design changes that do not deviate from the main purpose of the present invention. In addition, various modifications can be made to the present invention within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. In addition, components with the same effect described in the above embodiments can be replaced with each other.

Claims

1. A method performed by a user equipment UE, comprising: When the UE is required by the upper layer to release the PC5-RRC connection for a certain target and / or detects that the side communication radio link of a certain target fails, the UE releases the PC5-RRC connection corresponding to the target, and the UE triggers the SL-DRB release process associated with the PC5-RRC connection; Alternatively, the UE receives a PC5-RRC message including SL-DRB release information indicating the release of the SL-DRB, and the UE triggers the SL-DRB release process associated with the PC5-RRC connection; In the SL-DRB release process, the UE determines the first condition, and when at least one of the first conditions is met, the UE releases the RLC entity and / or the corresponding logical channel associated with the SL-DRB; and the UE determines the second condition, and when at least one of the second conditions is met, the UE executes the release of the PC5 relay RLC channel associated with the SL-DRB.

2. The method according to claim 1, wherein: The first condition includes at least one of the following: -The SL-DRB is the SL-DRB of each hop; - the SL-DRB is not an end-to-end SL-DRB; - no SL-DRB is associated with the RLC channel or RLC entity to which the SL-DRB is associated; - no other SL-DRB other than the SL-DRB is associated with the RLC channel or RLC entity to which the SL-DRB is associated, The second condition includes at least one of the following: - the SL-DRB is an end-to-end SL-DRB; - the SL-DRB is not a per-hop SL-DRB; - No end-to-end SL-DRB is associated with the PC5 relay RLC channel to which the SL-DRB is associated; - No other end-to-end SL-DRB other than the SL-DRB is associated with the PC5 relay RLC channel to which the SL-DRB is associated.

3. The method according to claim 1, wherein: When the UE is required by the upper layer to release the PC5-RRC connection for a certain target, and / or detects that the side communication radio link of a certain target fails, and / or receives a side communication RRC reconfiguration message sent by a certain target containing a side communication reset configuration, the UE processes the MAC layer. When at least one of the following conditions is met, the processing performed by the UE on the MAC layer is to reset the MAC specific to the sideline communication of the target: - except that the PC5-RRC connection of the target is an end-to-end PC5-RRC connection; -The target PC5-RRC connection is a PC5-RRC connection for each hop; - The target's PC5-RRC connection is not an end-to-end PC5-RRC connection.

4. A user equipment, comprising: processor; as well as Memory, which stores instructions, Wherein, when the instructions are executed by the processor, the method according to any one of claims 1 to 3 is performed.

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