CN109644361B

CN109644361B - Method and equipment for monitoring RLM (radio link management) by radio link

Info

Publication number: CN109644361B
Application number: CN201880003067.7A
Authority: CN
Inventors: 史志华; 陈文洪
Original assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2018-02-14
Filing date: 2018-02-14
Publication date: 2020-09-29
Anticipated expiration: 2038-02-14
Also published as: WO2019157750A1; CN109644361A

Abstract

The embodiment of the application discloses a method and equipment for monitoring RLM measurement by a wireless link, wherein terminal equipment receives a plurality of reference signals with a first quasi co-located QCL relation on a plurality of bandwidth parts BWP; the terminal device determines a target reference signal for RLM measurement in the plurality of reference signals; and the terminal equipment carries out RLM measurement based on the target reference signal.

Description

Method and equipment for monitoring RLM (radio link management) by radio link

Technical Field

The embodiments of the present application relate to the field of communications, and more particularly, to a method and apparatus for radio link monitoring RLM.

Background

In a New wireless (NR) system Of 5G, a concept Of BandWidth Part (BWP) IS introduced, a plurality Of BWPs can be configured on a terminal device, only one BWP IS activated at a time, the terminal device performs Radio Link Monitoring (RLM) measurement only on the activated BWPs, and specifically, the terminal device can perform RLM measurement on Radio Link monitoring Reference signals (RLM-RS) on the BWPs, determine Link conditions, and then report the Link conditions, such as In Synchronization (IS) or Out-Of-Synchronization (OOS), to a network device.

However, the RLM-RS configuration parameters, such as period, time offset, etc., on multiple BWPs may be different, and how to perform RLM measurement is an urgent problem to be solved.

Disclosure of Invention

The embodiment of the application provides a method and a device for monitoring RLM measurement of a wireless link, which can perform RLM measurement according to reference signals satisfying QCL relationship on a plurality of BWPs.

In a first aspect, a method for radio link monitoring, RLM, measurement is provided, including:

a terminal device receives a plurality of reference signals with a first quasi co-located QCL relationship over a plurality of bandwidth portions BWP; the terminal device determines a target reference signal for RLM measurement in the plurality of reference signals; and the terminal equipment carries out RLM measurement based on the target reference signal.

Optionally, in this embodiment of the present application, the Reference Signal (RS) may be a demodulation Reference Signal (DMRS) for demodulating a Physical Broadcast Channel (PBCH), or a Channel State Information Reference Signal (CSI-RS), or a synchronization Signal block, or a synchronization Signal, or a synchronization Channel, or another downlink Signal, which is not limited in this embodiment of the present application.

In one possible implementation, the reference signals in the target reference signal are from the same transmission beam.

Alternatively, the reference signals in the target reference signals may also be from the same antenna port, that is, the reference signals from the same beam or port may be considered as the reference signals satisfying the QCL.

In one possible implementation, the determining, by the terminal device, a target reference signal for RLM measurement in the plurality of reference signals includes:

the terminal device determines one or more of the plurality of reference signals as the target reference signal.

In one possible implementation, the determining, by the terminal device, one or more reference signals of the plurality of reference signals as the target reference signal includes:

and the terminal equipment determines one reference signal as the target reference signal in the plurality of reference signals according to the period of the reference signal.

In a possible implementation manner, the one reference signal is a reference signal with a shortest period among the plurality of reference signals.

the terminal device determines a Kth reference signal in the plurality of reference signals as the target reference signal, wherein K is a positive integer.

In one possible implementation, K is predefined or determined by the terminal device.

the terminal device determines all the reference signals in the plurality of reference signals to be the target reference signal.

In one possible implementation manner, the performing, by the terminal device, RLM measurement based on the target reference signal includes:

and the terminal equipment carries out RLM measurement on the plurality of reference signals in sequence from the first received reference signal.

In a possible implementation manner, the performing, by the terminal device, RLM measurement on the plurality of reference signals sequentially starting from a first received reference signal includes:

if the measurement result of the L-th received reference signal IS greater than the block error rate (BLER) threshold of the synchronous state IS, the terminal equipment stops RLM measurement and reports the IS to the network equipment, wherein L IS a positive integer; or

And if the measurement result of the L-th received reference signal is smaller than the OOS block error rate BLER threshold in the asynchronous state, the terminal equipment performs RLM measurement on the L + 1-th received reference signal.

Therefore, the end condition for RLM measurement of a target reference signal in a set of reference signals that satisfy the QCL relationship is that the measurement result of a certain reference signal satisfies a first condition, or that the measurement results of all reference signals in the first QCL set satisfy a second condition.

Optionally, if the measurement result of the target reference signal in the first QCL group IS greater than the IS BLER, the terminal device may stop measuring the target reference signal in the subsequent QCL group, and report the IS to the network device.

Optionally, if the measurement results of all the target reference signals in the first QCL group are less than the OOS BLER, the terminal device may continue to perform RLM measurement on the target reference signals in other non-measured QCL groups, and when the measurement results of the target reference signals in all the QCL groups satisfy the second condition, the terminal device may report the OOS to the network device, and if the measurement results of the target reference signals in one QCL group in the plurality of QCL groups satisfy the first condition, the terminal device may determine to report the IS to the network device.

Optionally, the reporting conditions for IS and OOS are only examples, and the terminal device may also report the IS to the terminal device IS when the measurement results of the target reference signals of at least two QCL groups satisfy the first condition, or may also report the IS to the terminal device when the measurement results of the target reference signals of all QCL groups satisfy the first condition, and the like.

In a second aspect, there is provided an apparatus for radio link monitoring, RLM, measurement, configured to perform the method of the first aspect or any possible implementation manner of the first aspect. In particular, the apparatus comprises means configured to perform the method of the first aspect or any possible implementation manner of the first aspect.

In a third aspect, there is provided an apparatus for radio link monitoring, RLM, measurement, the apparatus comprising: memory, processor, input interface and output interface. The memory, the processor, the input interface and the output interface are connected through a bus system. The memory is configured to store instructions, and the processor is configured to execute the instructions stored by the memory and is configured to perform the method of the first aspect or any possible implementation manner of the first aspect.

In a fourth aspect, there is provided a computer storage medium configured to store computer software instructions for executing the method of the first aspect or any possible implementation manner of the first aspect, and comprising a program configured to execute the above aspects.

In a fifth aspect, there is provided a computer program product comprising instructions which, when run on a computer, cause the computer to perform the method of the first aspect or any of the alternative implementations of the first aspect.

Drawings

Fig. 1 is a schematic diagram of a communication system to which embodiments of the present application are applicable;

fig. 2 is a schematic flow chart of a method of radio link monitoring, RLM, measurement according to an embodiment of the present application;

fig. 3 is a schematic diagram of an apparatus for radio link monitoring RLM measurement according to an embodiment of the present application;

fig. 4 is a schematic diagram of an apparatus for radio link monitoring RLM measurement according to another embodiment of the present application.

Detailed Description

The technical scheme of the embodiment of the application can be applied to various communication systems, for example: a global system for Mobile communications (GSM) system, a Code Division Multiple Access (CDMA) system, a Wideband Code Division Multiple Access (WCDMA) system, a General Packet Radio Service (GPRS), a Long Term Evolution (Long Term Evolution, LTE) system, a Frequency Division Duplex (FDD) system, a Time Division Duplex (TDD), a Universal Mobile Telecommunications System (UMTS), a Worldwide Interoperability for microwave Access (WiMAX) communication system, or a future 5G system.

Fig. 1 illustrates a wireless communication system 100 to which an embodiment of the present application is applied. The wireless communication system 100 may include a network device 110. Network device 100 may be a device that communicates with a terminal device. Network device 100 may provide communication coverage for a particular geographic area and may communicate with terminal devices (e.g., UEs) located within the coverage area. Optionally, the Network device 100 may be a Base Transceiver Station (BTS) in a GSM system or a CDMA system, a Base Station (NodeB, NB) in a WCDMA system, an evolved node B (eNB or eNodeB) in an LTE system, or a wireless controller in a Cloud Radio Access Network (CRAN), or a Network device in a relay Station, an Access point, a vehicle-mounted device, a wearable device, a Network-side device in a future 5G Network, or a Network device in a future evolved Public Land Mobile Network (PLMN), or the like.

The wireless communication system 100 also includes at least one terminal device 120 located within the coverage area of the network device 110. The terminal device 120 may be mobile or stationary. Alternatively, terminal Equipment 120 may refer to an access terminal, User Equipment (UE), subscriber unit, subscriber station, mobile station, remote terminal, mobile device, User terminal, wireless communication device, User agent, or User Equipment. An access terminal may be a cellular telephone, a cordless telephone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA), a handheld device having Wireless communication capabilities, a computing device or other processing device connected to a Wireless modem, a vehicle mounted device, a wearable device, a terminal device in a future 5G network or a terminal device in a future evolved PLMN, etc.

Fig. 2 is a schematic flow chart of a method 200 for radio link monitoring RLM measurement provided in an embodiment of the present application, where the method 200 may be performed by a terminal device in the communication system 100 shown in fig. 1, and as shown in fig. 2, the method 200 may include the following:

s210, a terminal device receives a plurality of reference signals with a first quasi co-located QCL relationship on a plurality of bandwidth parts BWP;

s220, the terminal equipment determines a target reference signal for RLM measurement in the plurality of reference signals;

s230, the terminal equipment carries out RLM measurement based on the target reference signal.

Therefore, according to the RLM measurement method in the embodiment of the present application, the terminal device may perform RLM measurement based on a group of reference signals that satisfy the QCL relationship on multiple BWPs, which is beneficial to reducing the number of RLM measurements performed by the terminal device, and thus can reduce the signaling overhead of the terminal device.

Alternatively, in this embodiment of the present application, the Reference Signal (RS) may be a demodulation Reference Signal (DMRS) for demodulating a Physical Broadcast Channel (PBCH), or a Channel State Information Reference Signal (CSI-RS), or a synchronization Signal block, or a synchronization Signal, or a synchronization Channel, or another downlink Signal, which is not limited in this embodiment.

Optionally, in this embodiment of the present application, if two reference signals are from the same beam, or from the same antenna port, etc., the two reference signals may be considered to be Quasi Co-located (QCL).

In this embodiment, the terminal device may receive multiple reference signals on multiple BWPs, where the multiple reference signals may satisfy a same QCL relationship or may satisfy different QCL relationships, for example, a part of the multiple reference signals may satisfy a first QCL relationship, another part of the multiple reference signals may satisfy a second QCL relationship, or the multiple reference signals may also satisfy more QCL relationships, which is not limited in this embodiment.

For the purpose of distinction and description, the reference signals received on the BWPs are divided into QCL groups according to the satisfied QCL relationship, i.e., each QCL group is a group of reference signals satisfying a certain QCL relationship, e.g., the QCL groups include a first QCL group and a second QCL group, the first QCL group is a group of reference signals satisfying the first QCL relationship among the reference signals, and the second QCL group is a group of reference signals satisfying the second QCL relationship among the reference signals.

In this embodiment, the terminal device may determine one or more reference signals in the first QCL group as the target reference signals corresponding to the first QCL group, and determine one or more reference signals in the second QCL group as the target reference signals corresponding to the second QCL group. Optionally, if the plurality of reference signals include more QCL groups, the terminal device may further determine target reference signals corresponding to other QCL groups, which is not limited in this embodiment of the present application.

For example, the multiple reference signals may include multiple reference signals from the same transmission beam (beam), e.g., RS1 and RS2 from transmission beam1, and RS3 and RS4 from transmission beam2, it may be determined that RS1 and RS2 satisfy the QCL relationship, and RS3 and RS4 satisfy the QCL relationship, and further, the RS1 and RS2 may be determined as a first QCL packet, and the RS3 and RS4 may be determined as a second QCL packet. I.e., the set of reference signals satisfying the QCL relationship may be reference signals from the same transmit beam.

Optionally, the periods of the multiple reference signals in the set of reference signals that satisfy the QCL relationship may be the same or different, which is not limited in this embodiment of the present application.

In this embodiment, the terminal device may determine a target reference signal for RLM measurement In the plurality Of reference signals, and specifically, the terminal device may determine one or more reference signals as the target reference signal for RLM In each QCL packet satisfying a QCL relationship In the plurality Of reference signals, and further, the terminal device may perform RLM measurement based on the target reference signal In each QCL packet In the plurality Of QCL packets, determine a radio link state, and perform reporting Of an In-Synchronization state (IS) or an Out-Of-Synchronization state (OOS).

It should be understood that the measurement of the terminal device on the target reference signal in the plurality of reference signals may be periodic, and the period may be referred to as an RLM measurement period, alternatively, the RLM measurement period may be determined according to the period of the reference signal, the number of reference signals, and other information, which is not limited in this embodiment of the present application.

Hereinafter, how to determine the target reference signal corresponding to the first QCL group will be described by taking the first QCL group satisfying the first QCL relationship among the plurality of reference signals as an example.

Example 1: all reference signals in the first QCL group may be taken as target reference signals to which the first QCL group corresponds.

Further, the terminal device may perform RLM measurement on all reference signals in the first QCL group, for example, the terminal device may perform RLM measurement on the reference signals in the first QCL group sequentially from a reference signal received by a first one of the first QCL group, and when a measurement result of a certain reference signal satisfies a first condition, stop performing RLM measurement on subsequent reference signals, and report the IS to the network device.

Here, when it needs to be described, the fact that the measurement result of the reference signal satisfies the first condition may be that the measurement result of the reference signal IS greater than an IS Block Error Rate (BLER) threshold, or may also be other determination conditions that can be used for determining that the link quality IS better, which IS not limited in this embodiment of the present application.

Optionally, if the measurement result of the kth received reference signal in the first QCL group satisfies the second condition, the terminal device continues to perform RLM measurement on other reference signals in the first QCL group until all reference signals are traversed, or if the measurement result of a certain reference signal satisfies the first condition, stops performing RLM measurement on subsequent reference signals.

Here, when it needs to be described, the second condition that the measurement result of the reference signal satisfies may be that the measurement result of the reference signal is smaller than the OSS BLER threshold, or may also be other determination conditions that can be used for determining that the link quality is poor, which is not limited in this embodiment of the present application.

In summary, in this embodiment, the end condition of RLM measurement on the target reference signals corresponding to the first QCL group is that the measurement result of a certain reference signal satisfies the first condition, or that the measurement results of all reference signals in the first QCL group satisfy the second condition.

Example 2: a particular reference signal in the first QCL group may be taken as a corresponding target reference signal for the first QCL group.

It should be understood that the specific reference signal may be the kth reference signal in the first QCL set, or may also be a reference signal satisfying other conditions, which is not limited in the embodiment of the present application.

Optionally, K may be predefined, or may also be determined by the terminal device itself, which is not limited in this embodiment of the application.

Further, the terminal device may perform RLM measurement on the specific reference signals in the first QCL group.

Optionally, if the measurement result of the specific reference signal meets the first condition, the terminal device may determine to stop processing the target reference signals in the other QCL groups, and report the IS to the network device, or if the measurement result of the specific reference signal meets the second condition, the terminal device may continue to perform RLM measurement on the target reference signals in the other QCL groups.

Example 3: the terminal device may also determine the target reference signal in the first QCL packet according to the period of the reference signal.

For example, the terminal device may determine the reference signal with the shortest period in the first QCL packet as the target reference signal, or may also determine the reference signal with the period satisfying other conditions, which is not limited in this embodiment of the present invention.

Further, the terminal device may perform RLM measurement on the target reference signal determined in the first QCL group, and the specific implementation process may refer to the relevant descriptions in embodiment 1 and embodiment 2, which are not described herein again.

Therefore, according to the descriptions of embodiment 1 to embodiment 3, the measurement result of the target reference signal in the first QCL packet can be obtained. Further, the terminal device may determine whether to continue RLM measurement for the target reference signals in other QCL packets according to the measurement result for the target reference signals in the first QCL packet.

For example, if there IS a measurement result satisfying the first condition in the measurement results of the target reference signals in the first QCL group, the terminal device may stop measuring the target reference signals in the subsequent QCL group, and report the IS to the network device.

Or, if the measurement results of all the target reference signals in the first QCL group satisfy the second condition, the terminal device may continue to perform RLM measurement on the target reference signals in other non-measured QCL groups, and when the measurement results of the target reference signals in all the QCL groups satisfy the second condition, the terminal device may report OOS to the network device, and if the measurement results of the target reference signals in one QCL group in the plurality of QCL groups satisfy the first condition, the terminal device may determine to report IS to the network device.

While method embodiments of the present application are described in detail above with reference to fig. 2, apparatus embodiments of the present application are described in detail below with reference to fig. 3-4, it being understood that apparatus embodiments correspond to method embodiments and that similar descriptions may refer to method embodiments.

Fig. 3 shows a schematic block diagram of an apparatus 300 for radio link monitoring, RLM, measurements according to an embodiment of the application. As shown in fig. 3, the apparatus 300 includes:

a communication module 310 configured to receive a plurality of reference signals having a first quasi co-located QCL relationship over a plurality of bandwidth portions BWP;

a determining module 320 configured to determine a target reference signal for RLM measurement among the plurality of reference signals;

a measurement module 330 configured to perform RLM measurements based on the target reference signal.

Optionally, in some embodiments, the reference signals in the target reference signals are from the same transmit beam.

Optionally, in some embodiments, the determining module 320 is specifically configured to:

determining one or more of the plurality of reference signals as the target reference signal.

and determining one reference signal as the target reference signal in the plurality of reference signals according to the period of the reference signal.

Optionally, in some embodiments, the one reference signal is a reference signal with a shortest period among the plurality of reference signals.

determining a Kth reference signal of the plurality of reference signals as the target reference signal, wherein K is a positive integer.

Optionally, in some embodiments, the K is predefined or determined by the terminal device.

determining that all of the plurality of reference signals are determined to be the target reference signal.

Optionally, in some embodiments, the measurement module is specifically configured to:

if the measurement result of the L-th received reference signal IS greater than the block error rate (BLER) threshold of the synchronous state IS, stopping RLM measurement, and reporting the IS to network equipment, wherein L IS a positive integer; or

And if the measurement result of the L-th received reference signal is smaller than the OOS block error rate BLER threshold in the asynchronous state, performing RLM measurement on the L + 1-th received reference signal.

It should be understood that the apparatus 300 for radio link monitoring RLM measurement according to the embodiment of the present application may correspond to a terminal device in the embodiment of the method of the present application, and the above and other operations and/or functions of each unit in the apparatus 300 are respectively for implementing a corresponding flow of the terminal device in the method 200 shown in fig. 2, and are not described herein again for brevity.

As shown in fig. 4, an apparatus 400 for radio link monitoring RLM measurement is further provided in the embodiments of the present application, where the apparatus 400 may be the apparatus 300 in fig. 3, which can be used to execute the contents of the terminal apparatus corresponding to the method 200 in fig. 2. The apparatus 400 comprises: an input interface 410, an output interface 420, a processor 430 and a memory 440, the input interface 410, the output interface 420, the processor 430 and the memory 440 may be connected by a bus system. The memory 440 is configured to store programs, instructions or code. The processor 430 is configured to execute the program, instructions or code in the memory 440 to control the input interface 410 to receive signals, control the output interface 420 to transmit signals, and perform the operations in the foregoing method embodiments.

It should be understood that, in the embodiment of the present application, the processor 430 may be a Central Processing Unit (CPU), and the processor 430 may also be other general processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), ready-to-use programmable gate arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, and the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

The memory 440 may include both read-only memory and random access memory, and provides instructions and data to the processor 430. A portion of memory 440 may also include non-volatile random access memory. For example, memory 440 may also store device type information.

In implementation, the various aspects of the methods described above may be performed by instructions in the form of hardware, integrated logic circuits, or software in processor 430. The contents of the method disclosed in connection with the embodiments of the present application may be directly embodied as a hardware processor, or may be implemented by a combination of hardware and software modules in a processor. The software module may be located in ram, flash memory, rom, prom, or eprom, registers, etc. storage media as is well known in the art. The storage medium is located in the memory 440, and the processor 430 reads the information in the memory 440 and implements the content of the above method in combination with its hardware. To avoid repetition, it is not described in detail here.

In a specific embodiment, the determining module 320 and the measuring module 320 included in the apparatus 300 in fig. 3 may be implemented by the processor 430 in fig. 4, and the communicating module 310 included in the apparatus 300 in fig. 3 may be implemented by the input interface 410 and the output interface 420 in fig. 4.

Embodiments of the present application also provide a computer-readable storage medium storing one or more programs, the one or more programs comprising instructions, which when executed by a portable electronic device comprising a plurality of application programs, enable the portable electronic device to perform the method of the embodiment shown in fig. 2.

The embodiment of the present application also provides a computer program, which includes instructions, when the computer program is executed by a computer, the computer may execute the corresponding flow of the method of the embodiment shown in fig. 2.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus, and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application may be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the methods described in the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method of radio link monitoring, RLM, comprising:

a terminal device receives a plurality of reference signals with a first quasi co-located QCL relationship over a plurality of bandwidth portions BWP;

the terminal device determines a target reference signal for RLM measurement in the plurality of reference signals;

and the terminal equipment carries out RLM measurement based on the target reference signal.

2. The method of claim 1, wherein reference signals in the target reference signals are from a same transmit beam.

3. The method of claim 1 or 2, wherein the terminal device determining a target reference signal for RLM measurements among the plurality of reference signals comprises:

4. The method of claim 3, wherein the terminal device determining one or more of the plurality of reference signals as the target reference signal comprises:

5. The method of claim 4, wherein the one reference signal is a reference signal with a shortest period among the plurality of reference signals.

6. The method of claim 3, wherein the terminal device determining one or more of the plurality of reference signals as the target reference signal comprises:

7. The method of claim 6, wherein the K is predefined or determined by a terminal device.

8. The method of claim 3, wherein the terminal device determining one or more of the plurality of reference signals as the target reference signal comprises:

9. The method of claim 8, wherein the terminal device performs RLM measurements based on the target reference signal, comprising:

10. The method of claim 9, wherein the terminal device performing RLM measurements on the plurality of reference signals sequentially from a first received reference signal comprises:

11. An apparatus for radio link monitoring, RLM, comprising:

a communication module configured to receive a plurality of reference signals having a first quasi co-located QCL relationship over a plurality of bandwidth portions BWP;

a determining module configured to determine a target reference signal for RLM measurement among the plurality of reference signals;

a measurement module configured to perform RLM measurements based on the target reference signal.

12. The device of claim 11, wherein reference signals in the target reference signals are from a same transmit beam.

13. The device according to claim 11 or 12, wherein the determining module is specifically configured to:

14. The device of claim 13, wherein the determination module is specifically configured to:

15. The apparatus of claim 14, wherein the one reference signal is a reference signal with a shortest period among the plurality of reference signals.

16. The device of claim 13, wherein the determination module is specifically configured to:

17. The device of claim 16, wherein K is predefined or determined by a terminal device.

18. The device of claim 13, wherein the determination module is specifically configured to:

19. The device of claim 18, wherein the measurement module is specifically configured to:

RLM measurements are performed on the plurality of reference signals sequentially starting with a first received reference signal.

20. The device of claim 19, wherein the measurement module is specifically configured to: