CN115623526A

CN115623526A - Method and user equipment for performing radio link monitoring

Info

Publication number: CN115623526A
Application number: CN202110806412.4A
Authority: CN
Inventors: 刘蕾; 刘仁茂
Original assignee: Sharp Corp
Current assignee: Sharp Corp
Priority date: 2021-07-16
Filing date: 2021-07-16
Publication date: 2023-01-17
Also published as: WO2023284831A1

Abstract

The invention provides a method for performing radio link monitoring performed by user equipment, comprising the following steps: for a user equipment configured with RLM relaxation, if a handover instruction instructing a handover of an RRC connection from a source side cell to a target side cell is received, an action is performed such that normal RLM is performed without performing the RLM relaxation in the source side cell for a predetermined period after the handover instruction is received.

Description

Method and user equipment for performing radio link monitoring

Technical Field

The present invention relates to the field of wireless communication technology, and more particularly, to a method for performing radio link monitoring by a user equipment and a corresponding user equipment.

Background

In 12.2019, on the third Generation Partnership project (3 rd Generation Partnership project:3 GPP) RAN #86 subcontract, a work project for the release 17 Power consumption Saving enhancement (see non-patent document: RP-193239New WID. The latest version of this work item is referred to non-patent literature: RP-200938Revised WID _UEPower Saving Enhancements for NR _Change. The work item mainly studies how the terminal saves power in the RRC idle state and the RRC inactive state. One of the goals of this work project is to study and evaluate wireless link monitoring of relaxed terminals in low mobility scenarios.

Radio Link Monitoring (RLM) is performed in the RRC connected state. For low mobility terminals, the radio link quality is generally relatively stable, and if such terminals are simultaneously configured with a short DRX cycle, the radio link may be monitored frequently with useless power consumption. In this case, after a certain criterion is determined, the terminal may relax the wireless link monitoring, for example, reduce the sampling times, lengthen the monitoring period, and so on. The criteria for the determination include a low-speed movement criterion and a good cell criterion, both of which are optionally configured by the network to the terminal.

The present invention discusses the relevant problem of how to perform radio link monitoring during handover.

Disclosure of Invention

An object of the present invention is to provide a method of performing radio link monitoring performed by a user equipment capable of avoiding power loss during RRC connection handover.

According to an aspect of the present invention, there is provided a method performed by a user equipment of performing radio link monitoring, comprising: for a user equipment configured with RLM relaxation, if a handover instruction instructing a handover of an RRC connection from a source side cell to a target side cell is received, an action is performed such that normal RLM is performed without performing the RLM relaxation in the source side cell for a predetermined period after the handover instruction is received.

Optionally, in the process that the RRC layer of the user equipment receives the out-of-synchronization indication to perform radio link failure detection, if the handover indication is received, an action of performing normal RLM without performing the RLM relaxation in the source cell may be performed.

Alternatively, when the RRC layer of the user equipment receives an out-of-synchronization indication to start performing radio link failure detection, if the handover indication has been received, a behavior may be performed such that the RLM relaxation is not performed in the source side cell and normal RLM is performed.

Optionally, the user equipment is configured to periodically perform radio link monitoring, and whenever the radio link monitoring starts to be performed, if the handover indication has been received, may perform an action such that the RLM relaxation is not performed within the source cell and normal RLM is performed.

Optionally, the method may further include: and if a handover instruction instructing a handover of the RRC connection from the source-side cell to the target-side cell is received, performing an action such that the RLM relaxation is not performed in the target-side cell and normal RLM is performed for a predetermined period after the handover instruction is received.

Optionally, the handover indication may include an RRC reconfiguration message carrying synchronization reconfiguration information.

Optionally, the handover indication may further include a DAPS handover indication indicating to perform a DAPS handover.

Alternatively, the predetermined period may be a period of execution of an RRC connection handover procedure indicated by the handover indication.

Optionally, the behavior comprises at least one of: exiting from the currently performing RLM relaxation and performing normal RLM; releasing the configured RLM relaxation criteria parameter; no RLM relaxation is performed even if the RLM relaxation criterion is met; the RLM relaxation criteria are ignored.

According to another aspect of the present invention, there is also provided a user equipment, including: a processor; and

a memory storing instructions, wherein the instructions, when executed by the processor, perform the method as described above.

According to the method of the invention, when RRC connection switching is carried out, RLM relaxation is not executed and normal RLM is executed, thereby avoiding that radio link monitoring is continued under the condition that radio link monitoring is unnecessary because radio link failure cannot be timely detected due to the RLM relaxation. Therefore, the waste of resources, unnecessary power loss and the like caused by unnecessary wireless link monitoring can be avoided.

Drawings

Fig. 1 is a flow diagram of a method of performing radio link monitoring according to one embodiment of the present invention.

Fig. 2 is a flowchart of a method of performing radio link monitoring according to another embodiment of the present invention.

Fig. 3 is a flow diagram of a method of performing radio link monitoring according to another embodiment of the present invention.

Fig. 4 is a flowchart of a method of performing radio link monitoring according to another embodiment of the present invention.

Fig. 5 is a block diagram schematically illustrating a user equipment UE according to the present invention.

Detailed Description

The invention is described in detail below with reference to the figures and the detailed description. It should be noted that the present invention should not be limited to the specific embodiments described below. In addition, for the sake of brevity, detailed descriptions of well-known technologies not directly related to the present invention are omitted so as to prevent the confusion of the understanding of the present invention.

Some terms are described below, and specific meanings of the terms are described in the latest 3GPP standard specification,

the UE: user Equipment

NR: new Radio New generation wireless technology

RRC: radio Resource Control

MAC: medium Access Control, medium Access Control

RRC _ CONNECTED: RRC connected state

RRC _ INACTIVE: RRC inactive state

RRC _ IDLE: RRC idle state

RAN: radio Access Network, radio Access stratum

Reference Signal Receiving Power, reference Signal Receiving Power

AS Access Stratum

PDCCH: physical downlink control channel, physical downlink control channel

Bandwidth Part, bandwidth fragment, BWP

DCI Downlink Control Information

DL: downlink, downlink

Information Element, information Element

And (3) CE: control Element, control Element

MIB Master Information Block, master Information Block

SIB System Information Block

RLM Radio Link Monitoring

BFD: beam Failure Detection, beam Failure Detection

RLF: radio Link Failure, radio Link Failure

BFR: beam Failure Recovery, beam Failure Recovery

BLER: block Error Rate, block Error Rate

RRM: radio Resource Management, radio Resource Management

Serving Cell A PCell, a PSCell, or an SCell, serving Cell, which may be PCell, PSCell or SCell

SpCell: the Special Cell may be a PCell or a PSCell.

A PCell: primary Cell, primary Cell

Primary SCG Cell, primary SCG Cell

SCell: secondary Cell, secondary Cell

SCG: secondary Cell Group, secondary Cell Group

C-RNTI Cell RNTI and Cell RNTI

RNTI: radio Network Temporary Identifier (RNTI)

HARQ: hybrid Automatic Repeat Request, hybrid Automatic Repeat Request retransmission

DAPS Dual Active Protocol Stack, dual Active Protocol Stack

SINR Signal to Noise and Interference Ratio

DRB (user) Data Radio Bearer

In the invention, a network, a base station and a RAN can be used interchangeably, and the network can 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 3 GPP.

In the present invention, the user equipment UE may refer to an NR device supporting an NR power consumption energy saving enhancement function described in the background art, may also refer to an NR device supporting relaxed radio link monitoring, and may also refer to another type of NR device or an LTE device.

In the present invention, "relaxed radio link monitoring relaxed RLM", "radio link monitoring relaxed mode RLM relaxation mode", and "radio link monitoring relaxation RLM relaxation" may be used interchangeably. In the present invention, "low mobility" may be replaced by "stationary", and "good serving cell quality" may be replaced by "non-cell-edge (not-at-cell-edge)" or "good cell (good cell)" or "good cell quality", and the like. "criterion/criterion", "evaluation" and "evaluation criterion/criterion" are mutually substituted. Also, these criteria/evaluation names may be modified by adding "RLM" and/or "parameter". "any DAPS radio bearer is configured" and "DAPS handover is configured", "DAPS handover is used" may be replaced with each other.

In the present invention, handover refers to a change of a primary cell initiated by a network side, where the change of the primary cell including inter-cell also includes a change of a primary cell in a cell, that is, a primary cell of a UE is changed from a source cell to a target cell, where the source cell and the target cell may be the same cell or different cells. The source Cell may also be called a source base station, or called a source beam (beam), a source Transmission point (TRP), a source Primary Cell (PCell), a source Special Cell (specific Cell, spCell), a source Primary Cell group MCG; the target cell may also be called a target base station, or a target beam, a target transmission point, a target primary cell PCell, a target special cell, a target cell group MCG. The source cell refers to a cell serving the UE, which is connected before the handover procedure is initiated, i.e., a cell that sends an RRC message containing a handover command to the UE. The target cell refers to a cell serving the UE to which the UE is connected after the handover procedure is successfully completed, or a cell indicated by the target cell identifier included in the handover command. The handover command of the present invention is used to trigger the UE to perform handover, and in the NR system, the handover command is an RRC reconfiguration message including a synchronization reconfiguration (synchronization width sync) Cell, and further, an RRC reconfiguration message including a synchronization reconfiguration (synchronization width sync) Cell for a Master Cell Group (MCG). At this time, the handover may also be referred to as a synchronous reconfiguration of the MCG. The synchronization reconfiguration cell may include configuration information of the target cell, such as a target cell identifier, a target cell frequency, a common configuration of the target cell, such as system information, a random access configuration used by the UE to access the target cell, a security parameter configuration of the UE in the target cell, a radio bearer configuration of the UE in the target cell, and the like. For convenience of description, the RRC reconfiguration message and the RRC connection reconfiguration message are equivalent in the present invention. The handover command is equivalent to an RRC message including the handover command, and refers to an RRC message or a configuration in the RRC message that triggers the UE to perform handover. The handover configuration refers to all or part of the configuration in the handover command. Cancellation, release, deletion, flush, and clear, etc. may be interchanged. Execution, use, adoption, and application are interchangeable. Configuration and reconfiguration may be alternative.

Hereinafter, a description will be given of the related art of the present invention.

RLM refers to a situation where a UE monitors the downlink radio link quality according to a reference signal configured by a network, in order to detect the downlink radio link quality of a special Cell SpCell (i.e., PCell, PSCell) or a serving Cell. The reference signals configured for the RLM procedure may be SSBs and/or CSI-RSs. The UE executes the RLM flow on the activated downlink BWP. To determine the quality of the downlink, the UE sets the BLER and Q of the downlink radio link based on the configured reference signals _out 、Q _in These two thresholds are compared. If the downlink radio link quality is lower than Q _out The physical layer sends out-of-sync indication to the upper layer; if the downlink radio link quality is higher than Q _in The physical layer sends an in-sync indication to the upper layer. Q _out Corresponding to an out-of-step BLER (e.g., 10%), indicating that the downlink cannot be reliably received; q _in Corresponding to a synchronous BLER (e.g., 2%), indicating that the downlink may be reliably received. When the RRC layer continuously receives the reports of N310 physical layers to the SThe out-of-sync indication of pCell then starts the T310 timer of the corresponding SpCell. During the operation of T310, when the RRC layer continuously receives the in-sync indication for the SpCell reported by the N311 physical layers, the T310 timer of the corresponding SpCell is stopped. When the T310 timer expires, the UE may consider that a radio link failure occurs, thereby triggering an RRC reestablishment procedure to recover the radio link.

For low mobility terminals, the radio link quality is generally relatively stable, and if such terminals are simultaneously configured with a short DRX cycle, the radio link may be monitored frequently with useless power consumption. In this case, after a certain criterion is determined, the terminal may relax the wireless link monitoring, such as reducing the sampling times, lengthening the monitoring evaluation period, lengthening the reporting indication period, and the like. In the RRC connected state, the RLM relaxation may be that the base station configures RLM relaxation criteria configuration parameters through system messages or RRC dedicated signaling, and the RLM relaxation criteria may include a low mobility criterion (low mobility) and a good serving cell quality criterion (good serving cell quality). The configuration parameters may include a switch of the criterion, a threshold of the criterion (SINR threshold, and/or RSRP threshold, and/or RSRQ threshold), a decision time parameter, and the like. The UE compares and evaluates the measurement result of SINR and/or RSRP/RSRQ of the SpCell or the serving cell with a threshold value in an RLM (radio link management) relaxation criterion, judges the mobility and the quality of the serving cell, and can adopt the relaxed RLM if the RLM relaxation criterion is met. The low-speed moving criterion and the good service cell quality criterion are configured optionally, if only the low-speed moving criterion is configured, the UE meets the low-speed moving criterion, namely RLM (or RLM relaxation for low-speed moving) can be carried out; if only the good serving cell quality criterion is configured, the UE satisfies the good serving cell quality criterion, i.e. RLM relaxation can be performed (or RLM relaxation of the good serving cell quality is performed); if the low-speed moving criterion and the good service cell quality criterion are configured, the UE detects the two criteria at the same time, and when the two criteria are met, RLM (or RLM relaxation at low speed moving and RLM relaxation at good service cell quality) are carried out; if both the low-speed mobility criterion and the good-serving cell quality criterion are configured, it is also possible that the UE satisfies one of the criteria, i.e., RLM relaxation is possible (or both RLM relaxation for low-speed mobility and RLM relaxation for good-serving cell quality are performed).

Release 16 introduced DAPS handover, which refers to a handover procedure in which a UE maintains a connection with a source base station after receiving an RRC message for handover, until a random access procedure to a target is successfully performed, and releases a source side connection. In the process, the UE continues to receive downlink data from the source base station until the source cell is released, and the UE continues to send uplink data to the source base station until the random access process to the target base station is successfully completed. The RRC message for handover, i.e. the RRC reconfiguration message containing the synchronization reconfiguration (synchronization within sync) information element, may configure the DRB as a DAPS bearer, and the UE may know whether to perform a DAPS handover procedure through the configuration. After receiving the RRC message for handover, the UE starts a T304 timer, which is stopped after the UE successfully completes random access at the target base station. In the process of DAPS handover, the UE continues to perform RLM on the source base station side, and if a radio link failure occurs on the source base station side, the UE suspends the transmission of DRBs of all source base stations and releases the source side connection. After the DAPS handover is completed, the UE receives an RRC reconfiguration message sent from the target base station, where the RRC reconfiguration message carries indication information (e.g., identified by a DAPS-SourceRelease information element) for indicating a release of the source base station, and after receiving the indication, the UE performs an operation of releasing the configuration of the source base station and the protocol stack.

One of the typical scenarios considered by the present invention is: the UE satisfies RLM relaxation criteria and performs RLM relaxation, and receives a handover command (e.g., a handover command with a DAPS bearer configuration) issued by the network side. In this scenario, the UE needs to exit from the relaxed RLM, that is, a normal RLM is used, otherwise if the relaxed RLM is continuously used, the UE cannot monitor the RLF in time, and continues to maintain data transmission and reception with the source base station under the condition that the link condition is not good, which wastes resources and consumes power.

First, the outline of the present invention will be described with reference to fig. 1 to 4. In the following description, substantially the same steps are not repeated in each embodiment, and only different points thereof will be described.

As shown in fig. 1, in S102, it is determined whether the user equipment is configured with RLM relaxation, and if the user equipment is not configured with RLM relaxation, the procedure is ended. S202, S302, and S402 in fig. 2 to 4, which will be described later, are all the same as S102, and will not be described repeatedly.

If the user equipment is configured with RLM relaxation, in S104, it is determined whether a handover instruction instructing a handover of an RRC connection from the source-side cell to the target-side cell is received for the user equipment configured with RLM relaxation. The handover indication may comprise, for example, an RRC reconfiguration message carrying the synchronization reconfiguration information. The handover indication may comprise, for example, a DAPS handover indication indicating that a DAPS handover is to be performed.

Upon receiving the switching instruction, in S106, it is determined whether a predetermined period of time after receiving the switching instruction has expired. The predetermined period may be, for example, the execution period of the RRC connection handover procedure indicated by the handover indication. Whether the predetermined period has expired may be determined, for example, by whether a T304 timer for indicating that a DAPS handover is in progress.

If the predetermined period has not expired, at S108, an action is performed such that no RLM relaxation is performed in the source side cell and normal RLM is performed. The behavior may include at least one of: exiting from the currently performing RLM relaxation and performing normal RLM; releasing the configured RLM relaxation criterion parameters; no RLM relaxation is performed even if the RLM relaxation criterion is met; the RLM relaxation criterion is ignored, i.e. no determination of the RLM relaxation criterion is made.

In another example, the behavior such that the RLM relaxation is not performed but the normal RLM is performed in the target side cell may also be performed within a predetermined period after the handover indication is received.

Fig. 2 is a flow diagram of a method of performing radio link monitoring according to another embodiment of the present invention.

The difference between the flow of fig. 2 and fig. 1 is that in 204, it is determined whether radio link failure detection is currently being performed. The "radio link failure detection is being performed" means that the RRC layer of the user equipment is in the process of receiving the out-of-synchronization indication and performing the radio link failure detection.

If it is in the process of performing radio link failure detection, it is determined whether a handover instruction is received at S206. The operations of S206 to S210 are the same as those of S104 to S108 described above, and the description is not repeated here.

The flow of fig. 3 is different from that of fig. 1 in that it is determined whether or not an out-of-sync instruction is received in S304. If the out-of-sync instruction is received, upon receiving the out-of-sync instruction, it is determined at S306 whether the user equipment has received the handover instruction (whether the handover instruction is past or received at the time when the out-of-sync instruction is received) at the time of receiving the out-of-sync instruction. If it is designated that the handover instruction is received, S308 to S310 are performed, i.e., the action of performing the RLM in the source cell without performing the RLM relaxation for a predetermined period and performing the normal RLM is performed. The execution of S308 to S310 is the same as the above-described S106 to S108, and the description is not repeated here.

Fig. 4 is a flow diagram of a method of performing radio link monitoring according to another embodiment of the present invention.

The embodiment of fig. 4 differs from that of fig. 1 in that in this embodiment the radio link monitoring is performed periodically. At S404, it is determined whether to start radio link monitoring. Each time radio link monitoring is started, at S406, it is determined whether a handover instruction has been received (whether the handover instruction has passed or whether the handover instruction was received at the time when the out-of-synchronization instruction was received). If the handover indication has been received, S408 to S410 are performed, i.e., the actions are performed within a predetermined period such that RLM relaxation is not performed in the source cell and normal RLM is performed. The execution of S408 to S410 is the same as S106 to S108 described above, and the description is not repeated here.

The embodiments described above with reference to fig. 1 to 4 may be combined with each other. For example, if it is determined in 306 that the handover indication is not received in the past in fig. 3, the schemes in fig. 2 may be combined, for example, the radio link failure detection may be started by receiving the out-of-synchronization indication for the first time, and in performing the radio link failure detection, if the handover indication is received, the behavior of performing the normal RLM without performing the RLM relaxation in the source cell is performed for a predetermined period. For another example, in fig. 4, if a handover instruction has not been received in the past every time radio link monitoring is started in S406, in the process of performing radio link monitoring next, if a handover instruction is received, the behavior of performing normal RLM without performing RLM relaxation in the source cell may be performed for a predetermined period.

Hereinafter, several specific embodiments of the present invention are described in detail.

Example 1

In this embodiment, the UE receives an RRC reconfiguration message, where the RRC reconfiguration message carries a reconfigurationWithSync cell.

Optionally, if any DAPS radio bearer is configured (any DAPS bearer is configured), the UE performs a first action, wherein the first action includes, but is not limited to, one or more of:

1) If the UE is in the RLM relay mode, the UE exits the RLM relay;

2) If the low mobility criterion parameter is configured, releasing the low mobility criterion parameter and/or not performing an RLM relax of low mobility;

3) If the good serving cell quality criterion parameter is configured, releasing the low mobility criterion parameter and/or not performing RLM relay of good serving cell quality;

4) Releasing the RLM relaxation criteria parameter if the RLM relaxation criteria parameter is configured;

5) Performing normal RLM, or not performing RLM relaxation, or performing RLM as if the low mobility criterion parameters and/or the good serving cell quality criterion were not configured;

6) The UE with the DAPS bearer performs normal RLM, or does not perform RLM relaxation, or performs RLM as if the low mobility criterion parameters and/or the good serving cell quality criterion were not configured;

7) The UE needs to meet the performance requirements (requirements) of the normal RLM.

The exit (exit) RLM replay can also be expressed as rollback (fallback) to normal RLM. The order of execution of the various actions described above is not limiting.

Further, if T304 is in operation, the UE performs a first action

Or, optionally, as long as the UE receives the RRC reconfiguration message and the message carries the reconfigurationWithSync element, the UE performs the first action.

Or, optionally, the UE receives an RRC reconfiguration message, and the RRC reconfiguration message carries a reconfigurationWithSync information element, and if T304 is in operation, the UE performs a first action.

Or, optionally, if any DAPS radio bearer is configured (any DAPS bearer is configured), the UE performs the first action in the source cell.

Or, optionally, as long as the UE receives the RRC reconfiguration message and the message carries the reconfigurationWithSync element, the UE performs the first action in the source cell.

Or, optionally, the UE receives an RRC reconfiguration message and carries a reconfigurationWithSync information element, and if T304 is in operation, the UE performs a first action in the source cell.

Or, alternatively, if any DAPS radio bearer is configured (any DAPS bearer is configured), the UE performs the first behavior at the target cell.

Or, optionally, as long as the UE receives the RRC reconfiguration message and the message carries the reconfigurationWithSync element, the UE performs the first action in the target cell.

Or, optionally, the UE receives an RRC reconfiguration message, and the RRC reconfiguration message carries a reconfigurationWithSync information element, and if T304 is in operation, the UE performs a first action in the target cell.

Example 2

In this embodiment, the UE performs radio link failure Detection (Detection of radio link failure), and in this process:

optionally, the UE determines that the UE performs a first action if any DAPS radio bearer is configured; or if T304 is in operation, the UE performs the first action.

Or, optionally, the UE determines that the UE performs the first action in the source cell if any DAPS radio bearer is configured; or if T304 is in operation, the UE performs a first action at the source cell.

Or, optionally, the UE determines that the UE performs the first action in the target cell if any DAPS radio bearer is configured; or if T304 is in operation, the UE performs a first action in the target cell.

Example 3

In this embodiment, the UE performs Radio Link Monitoring (Radio Link Monitoring), and in this process:

optionally, the UE determines that if any DAPS radio bearer is configured, the UE performs a first action; or if T304 is in operation, the UE performs the first action.

Or, optionally, the UE determines that the UE performs the first action in the source cell if any DAPS radio bearer is configured; or if T304 is in operation, the UE performs a first action in the source cell.

Example 4

The present embodiment is a method of transmitting an RRC reconfiguration message performed by a base station when triggering a UE to perform handover. Optionally, when configuring the UE with the handover indication for switching the RRC connection, the base station may not configure the RLM relaxation criterion parameter for the UE, or instruct the UE to release the RLM relaxation criterion parameter configured before. The handover indication may be, for example, an RRC reconfiguration message. Optionally, the RRC reconfiguration message carries a reconfigurationWithSync element, and if any bearer is configured as a DAPS bearer, the message does not configure RLM relaxation criterion parameters, or releases the RLM relaxation criterion parameters configured before in the message.

Or optionally, the message carries a reconfigurationWithSync information element, if the RLM release criterion parameter is configured in the message, no bearer is configured as a DAPS bearer, or if the RLM release criterion parameter is configured before the RRC reconfiguration message, no bearer is configured as a DAPS bearer.

Fig. 5 is a block diagram schematically illustrating a user equipment UE according to the present invention. As shown in fig. 5, the user equipment UE50 comprises a processor 51 and a memory 52. The processor 51 may comprise, for example, a microprocessor, microcontroller, embedded processor, or the like. The memory 52 may include, for example, volatile memory (e.g., random access memory RAM), a Hard Disk Drive (HDD), non-volatile memory (e.g., flash memory), or other memory, among others. The memory 52 has stored thereon program instructions. Which when executed by the processor 51 may perform the above-described method performed by the user equipment as detailed in the present invention.

The program running on the apparatus according to the present invention may be a program that causes a computer to realize the functions of the embodiments of the present invention by controlling a Central Processing Unit (CPU). The program or information processed by the program may be temporarily stored in a volatile memory (such as a random access memory RAM), a Hard Disk Drive (HDD), a nonvolatile memory (such as a flash memory), or other memory system.

A program for implementing the functions of the embodiments of the present invention may be recorded on a computer-readable recording medium. The corresponding functions can be realized by causing a computer system to read the programs recorded on the recording medium and execute the programs. The term "computer system" as used herein may be a computer system embedded in the device and may include an operating system or hardware (e.g., peripheral devices). The "computer-readable recording medium" may be a semiconductor recording medium, an optical recording medium, a magnetic recording medium, a recording medium that stores a program for short-term dynamics, or any other recording medium that is readable by a computer.

The various features or functional blocks of the devices used in the above embodiments may be implemented or performed by circuitry (e.g., a single or multi-chip integrated circuit). Circuitry designed to perform the functions described herein 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 device, discrete gate or transistor logic, discrete hardware components, or any combination thereof. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The circuit may be a digital circuit or an analog circuit. Where new integrated circuit technologies have emerged as a replacement for 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.

Further, the present invention is not limited to the above-described embodiments. While 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 may be used as terminal devices or communication devices, such as AV devices, kitchen devices, cleaning devices, air conditioners, office devices, vending machines, and other home appliances.

As above, the embodiments of the present invention have been described in detail with reference to the accompanying drawings. However, the specific configuration is not limited to the above embodiment, and the present invention includes any design modification without departing from the gist of the present invention. In addition, the present invention can be variously modified 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 invention. Further, components having the same effects described in the above embodiments may be substituted for each other.

Claims

1. A method performed by a user equipment of performing radio link monitoring, comprising:

for a user equipment configured with RLM relaxation, if a handover instruction instructing a handover of an RRC connection from a source side cell to a target side cell is received, an action is performed such that normal RLM is performed without performing the RLM relaxation in the source side cell for a predetermined period after the handover instruction is received.

2. The method of claim 1, wherein, if a handover indication is received indicating that an RRC connection is handed over from a source-side cell to a target-side cell, performing an action such that normal RLM is performed without performing the RLM relaxation in the source-side cell for a predetermined period after receiving the handover indication comprises:

in a process in which the RRC layer of the user equipment receives the out-of-synchronization indication to perform radio link failure detection, if the handover indication is received, a behavior is performed such that the RLM relaxation is not performed in the source side cell and normal RLM is performed.

3. The method of claim 1, wherein, if a handover indication is received indicating that an RRC connection is handed over from a source-side cell to a target-side cell, performing an action such that normal RLM is performed without performing the RLM relaxation in the source-side cell for a predetermined period after receiving the handover indication comprises:

when the RRC layer of the user equipment receives an out-of-synchronization indication to start performing radio link failure detection, if the handover indication has been received, performing an action such that the RLM relaxation is not performed in the source side cell and normal RLM is performed.

4. The method of claim 1, wherein the user equipment is configured to periodically perform radio link monitoring,

performing, within a predetermined period after receiving a handover instruction instructing a handover of an RRC connection from a source side cell to a target side cell, an action such that a normal RLM is performed without performing the RLM relaxation in the source side cell includes:

performing an action such that the RLM relaxation is not performed within the source cell and a normal RLM is performed, if the handover indication has been received, whenever the radio link monitoring starts to be performed.

5. The method of claim 1, further comprising:

and if a handover instruction instructing a handover of the RRC connection from the source-side cell to the target-side cell is received, performing an action such that the RLM relaxation is not performed in the target-side cell and normal RLM is performed for a predetermined period after the handover instruction is received.

6. The method of any of claims 1-5, wherein the handover indication comprises an RRC reconfiguration message carrying synchronized reconfiguration information.

7. The method of claim 6, wherein the handover indication further comprises a DAPS handover indication indicating that a DAPS handover is performed.

8. The method according to any of claims 1-5, wherein the predetermined period is a period of execution of an RRC connection handover procedure indicated by the handover indication.

9. The method of any of claims 1-5, wherein the behavior comprises at least one of:

exiting from the currently performing RLM relaxation and performing normal RLM;

releasing the configured RLM relaxation criterion parameters;

no RLM relaxation is performed even if the RLM relaxation criterion is satisfied;

ignoring the RLM relaxation criterion.

10. A user equipment, comprising:

a processor; and

a memory having stored therein instructions that, when executed,

wherein the instructions, when executed by the processor, perform the method of any of claims 1 to 9.