TECHNICAL FIELD

This application relates to the communications field, and more specifically, to a radio link monitoring method and apparatus in the communications field.

BACKGROUND

In a wireless communications technology, radio link quality (or channel quality) is an important parameter for ensuring normal data transmission. To enable a system to learn of radio link quality in time, a terminal device may perform radio link monitoring (RLM) in a bandwidth. Simply, the terminal device may periodically measure the bandwidth by using a reference signal used for the RLM, and generate a measurement result used to indicate the radio link quality, to report the measurement result to a higher layer of the terminal device. The measurement result may include a quantity of out of synchronization (OOS) states or a quantity of in synchronization (IS) states.

In addition, in a 5G system, a bandwidth part (BWP) is proposed, and the BWP is a part of a system bandwidth. A network device may configure a plurality of BWPs for the terminal device, and the terminal device may perform RLM in an active BWP in the plurality of BWPs.

In an application scenario, in a first time period, the terminal device performs RLM in a BWP #A, to generate a corresponding measurement result #A. In a second time period, the terminal device needs to switch from the BWP #A to a BWP #B, and when performing RLM in the BWP #B, the terminal device continues to perform RLM based on the measurement result #A.

In this case, the measurement result #A generated by the terminal device by performing RLM in the BWP #A cannot accurately reflect a radio link status in the BWP #B. Consequently, accuracy of the RLM performed by the terminal device in the BWP #B is reduced, and communication quality is affected.

Therefore, a technology needs to be provided to improve the accuracy of the RLM performed in a process in which the terminal device performs RLM after switching the BWP, thereby improving the communication quality.

SUMMARY

This application provides a radio link monitoring method and apparatus, to improve accuracy of RLM and further improve communication quality.

According to a first aspect, a radio link monitoring method is provided. The method includes:

performing, by a terminal device, radio link monitoring RLM in a second bandwidth part BWP;

receiving, by the terminal device, first switching information sent by a network device, where the first switching information is used to indicate that an active bandwidth part BWP includes a first BWP;

switching, by the terminal device, from the second BWP to the first BWP based on the first switching information:

removing, by the terminal device, a measurement result obtained by performing RLM in the second BWP, where the measurement result includes a quantity N1 of at least some out of synchronization OOS states or a quantity N2 of at least some in synchronization IS states; and

performing, by the terminal device, RLM in the first BWP.

Therefore, according to the radio link monitoring method provided in this embodiment of this application, after switching from the second BWP in which the RLM is currently performed to the first BWP, the terminal device removes the measurement result obtained by performing RLM in the second BWP, where the measurement result is all or some of measurement results obtained by performing RLM in the second BWP, so that the terminal device does not use the measurement result in a process of performing RLM in the first BWP, to avoid a problem in the prior art that accuracy of the RLM is relatively low because all the measurement results are used in the process of performing RLM in the first BWP, thereby effectively improving accuracy of the RLM performed by the terminal device in the first BWP that is switched to, and further improving communication quality.

In a possible implementation, the removing, by the terminal device, a measurement result obtained by performing RLM in the second BWP includes:

counting, by the terminal device starting from P1, a quantity of consecutive OOS states, where the measurement result includes the quantity N1 of at least some OOS states, P1=Q1−N1. Q1 is a quantity of consecutive OOS states that is counted by the terminal device by performing RLM in the second BWP, and N1 is less than or equal to Q1; or

counting, by the terminal device starting from P2, a quantity of consecutive IS states, where the measurement result includes the quantity N2 of at least some IS states, P2=Q2-N2, Q2 is a quantity of consecutive IS states that is counted by the terminal device by performing RLM in the second BWP, and N2 is less than or equal to Q2.

In a possible implementation, the measurement result further includes at least partial duration T1 of total duration recorded from a time at which an RLM timer is enabled to a time at which the RLM timer is stopped; and

the removing, by the terminal device, a measurement result obtained by performing RLM in the second BWP includes:

starting, by the terminal device, timing from T2, where T2=T-T1, T is the total duration recorded from the time at which the RLM timer is enabled to the time at which the RLM timer is stopped, and T1 is less than or equal to T.

In a possible implementation, the first BWP and the second BWP do not overlap at all or partially overlap.

In a possible implementation, the method further includes:

receiving, by the terminal device, indication information sent by the network device, where the indication information is used to indicate the terminal device to remove the measurement result in the process of performing RLM in the first BWP.

In a possible implementation, the method further includes:

storing, by the terminal device, the measurement result;

receiving, by the terminal device, second switching information, where the second switching information is used to indicate the second BWP:

switching, by the terminal device, from the first BWP to the second BWP based on the second switching information; and

performing, by the terminal device, RLM in the second BWP based on the measurement result.

In a possible implementation, the performing, by the terminal device, RLM in the second BWP based on the measurement result includes:

counting, by the terminal device starting from N1, a quantity of consecutive OOS states, where the measurement result includes the quantity N1 of OOS states; or

counting, by the terminal device starting from N2, a quantity of consecutive IS states, where the measurement result includes the quantity N2 of IS states.

In a possible implementation, the measurement result further includes at least partial duration T1 of total duration recorded from a time at which an RLM timer is enabled to a time at which the RLM timer is stopped; and

the performing, by the terminal device. RLM in the second BWP based on the measurement result includes:

starting, by the terminal device, timing from T1.

According to a second aspect, a radio link monitoring method is provided. The method includes:

performing, by a terminal device, radio link monitoring RLM in a second bandwidth part BWP;

receiving, by the terminal device, first switching information sent by a network device, where the first switching information is used to indicate that an active bandwidth part BWP includes a first BWP;

switching, by the terminal device, from the second BWP to the first BWP based on the first switching information;

receiving, by the terminal device, indication information sent by the network device, where the indication information is used to indicate the terminal device to continue to use, in a process of performing RLM in the first BWP, a measurement result obtained by performing RLM in the second BWP; and the measurement result includes a quantity N1 of at least some out of synchronization OOS states or a quantity N2 of at least some in synchronization IS states; and

performing, by the terminal device, RLM in the first BWP based on the measurement result.

Therefore, according to the radio link monitoring method provided in this embodiment of this application, the network device sends, to the terminal device, the indication information used to indicate the terminal device to continue to use, in the process of performing RLM in the first BWP, the measurement result obtained by performing RLM in the second BWP, where the measurement result is all or some of measurement results obtained by performing RLM in the second BWP, so that the terminal device may continue to use the measurement result in the process of performing RLM in the first BWP, thereby improving RLM efficiency.

In a possible implementation, the first BWP and the second BWP partially overlap, or the first BWP and the second BWP do not overlap.

In a possible implementation, the performing, by the terminal device, RLM in the first BWP based on the measurement result includes:

counting, by the terminal device starting from N1, a quantity of consecutive OOS states, where the measurement result includes the quantity N1 of at least some OOS states; or

counting, by the terminal device starting from N2, a quantity of consecutive IS states, where the measurement result includes the quantity N2 of at least some IS states.

In a possible implementation, the measurement result further includes at least partial duration T1 of total duration recorded from a time at which an RLM timer is enabled to a time at which the RLM timer is stopped; and

the performing, by the terminal device, RLM in the first BWP based on the measurement result includes:

starting, by the terminal device, timing from T1.

According to a third aspect, a radio link monitoring method is provided. The method includes:

performing, by a terminal device, radio link monitoring RLM in a second bandwidth part BWP;

receiving, by the terminal device, first switching information sent by a network device, where the first switching information is used to indicate that an active BWP includes a first BWP;

switching, by the terminal device, from the second BWP to the first BWP based on the first switching information;

storing, by the terminal device, a measurement result obtained by performing RLM in the second BWP, where the measurement result includes a quantity N1 of at least some out of synchronization OOS states or a quantity N2 of at least some in synchronization IS states:

performing, by the terminal device. RLM in the first BWP;

receiving, by the terminal device, second switching information sent by the network device, where the second switching information is used to indicate that the active BWP includes the second BWP:

switching, by the terminal device, from the first BWP to the second BWP based on the second switching information; and

performing, by the terminal device, RLM in the second BWP based on the measurement result.

Therefore, according to the radio link monitoring method provided in this application, after switching from the second BWP in which the RLM is currently performed to the first BWP, the terminal device may store the measurement result obtained by performing RLM in the second BWP, where the measurement result is all or some of measurement results obtained by performing RLM in the second BWP, so that after subsequently switching from the first BWP to the second BWP, the terminal device may continue to perform RLM in the second BWP by continuing to use the measurement result, thereby reducing implementation complexity.

In a possible implementation, the performing, by the terminal device, RLM in the second BWP based on the measurement result includes:

counting, by the terminal device starting from N1, a quantity of consecutive OOS states, where the measurement result includes the quantity N1 of at least some OOS states; or

counting, by the terminal device starting from N2, a quantity of consecutive IS states, where the measurement result includes the quantity N2 of at least some IS states.

In a possible implementation, the measurement result further includes at least partial duration T1 of total duration recorded from a time at which an RLM timer is enabled to a time at which the RLM timer is stopped; and

the performing, by the terminal device, RLM in the second BWP based on the measurement result includes:

starting, by the terminal device, timing from T1.

According to a fourth aspect, a radio link monitoring method is provided. The method includes:

receiving, by a terminal device, first indication information sent by a network device, where the first indication information is used to indicate that active bandwidth parts BWPs include M BWPs, and M is an integer greater than 1:

performing, by the terminal device, RLM in K BWPs of the M BWPs based on the first indication information, where K is an integer greater than 1, and K is less than or equal to M; and

reporting, by the terminal device, a measurement result to a higher layer of the terminal device, where the measurement result includes an out of synchronization OOS state or an in synchronization IS state.

Therefore, according to the radio link monitoring method provided in this embodiment of this application, when the terminal device can perform wireless communication by using the M BWPs, the terminal device can determine a radio link status of the terminal device by performing RLM in the K BWPs of the M BWPs, thereby effectively reducing complexity of the RLM.

In a possible implementation, the reporting, by the terminal device, a measurement result to a higher layer of the terminal device includes:

averaging, by the terminal device, K measurement values that are obtained by performing RLM in the K BWPs in a first time period, to obtain a first average measurement value, where the K BWPs correspond one-to-one to the K measurement values; and

if a bit error rate obtained based on the first average measurement value is greater than a preset threshold, reporting, by the terminal device, the OOS state.

In a possible implementation, the reporting, by the terminal device, a measurement result to a higher layer of the terminal device includes:

averaging, by the terminal device, K measurement values that are obtained by performing RLM in the K BWPs in a second time period, to obtain a second average measurement value, where the K BWPs correspond one-to-one to the K measurement values; and

if a bit error rate obtained based on the second average measurement value is less than a preset threshold, reporting, by the terminal device, the IS state.

In a possible implementation, the reporting, by the terminal device, a measurement result to a higher layer of the terminal device includes:

performing, by the terminal device, RLM in the K BWPs in a third time period, to obtain K bit error rates that correspond one-to-one to the K BWPs; and

if L1 bit error rates of the K bit error rates are all greater than a preset threshold, reporting, by the terminal device, the OOS state, where L1 is an integer greater than or equal to 1, and L1 is less than or equal to K.

In a possible implementation, the reporting, by the terminal device, a measurement result to a higher layer of the terminal device includes:

performing, by the terminal device, RLM in the K BWPs in a fourth time period, to obtain K bit error rates that correspond one-to-one to the K BWPs; and

if L2 bit error rates of the K bit error rates are less than a preset threshold, reporting, by the terminal device, the IS state, where L2 is an integer greater than or equal to 1, and L2 is less than or equal to K.

In a possible implementation, the method further includes:

receiving, by the terminal device, second indication information sent by the network device, where the second indication information is used to indicate the K BWPs, and K is less than M; and

the performing, by the terminal device, RLM in K BWPs of the M BWPs based on the first indication information includes:

performing, by the terminal device, RLM in the K BWPs of the M BWPs based on the first indication information and the second indication information.

According to a fifth aspect, a radio link monitoring method is provided. The method includes:

performing, by a terminal device, radio link monitoring RLM in S second bandwidth parts BWPs, where S is an integer greater than 1;

receiving, by the terminal device, first switching information sent by a network device, where the first switching information is used to indicate that active BWPs include M first BWPs, and M is an integer greater than 1;

switching, by the terminal device, from the S second BWPs to the M first BWPs based on the first switching information;

removing, by the terminal device, a measurement result obtained by performing RLM in the S second BWPs, where the measurement result includes a quantity N3 of at least some out of synchronization OOS states or a quantity N4 of at least some in synchronization IS states; and

performing, by the terminal device, RLM in K first BWPs of the M first BWPs, where K is an integer greater than 1, and K is less than or equal to M.

In a possible implementation, the removing, by the terminal device, a measurement result obtained by performing RLM in the S second BWPs includes:

counting, by the terminal device starting from P3, a quantity of consecutive OOS states, where the measurement result includes the quantity N3 of at least some OOS states, P3=Q3−N3. Q3 is a quantity of consecutive OOS states that is counted by the terminal device by performing RLM in the S second BWPs, and N3 is less than or equal to Q3; or

counting, by the terminal device starting from P4, a quantity of consecutive IS states, where the measurement result includes the quantity N4 of at least some IS states, P4=Q4−N4, Q4 is a quantity of consecutive IS states that is counted by the terminal device by performing RLM in the S second BWPs. and N4 is less than or equal to Q4.

In a possible implementation, the measurement result further includes at least partial duration T3 of total duration recorded from a time at which an RLM timer is enabled to a time at which the RLM timer is stopped; and the removing, by the terminal device, a measurement result obtained by performing RLM in the S second BWPs includes:

starting, by the terminal device, timing from T4, where T4=T−T3, T is the total duration recorded from the time at which the RLM timer is enabled to the time at which the RLM timer is stopped, and T3 is less than or equal to T.

In a possible implementation, the M first BWPs and the S second BWPs do not overlap at all or partially overlap.

In a possible implementation, the method further includes:

receiving, by the terminal device, indication information sent by the network device, where the indication information is used to indicate the terminal device to remove the measurement result in a process of performing RLM in the M first BWPs.

In a possible implementation, the performing, by the terminal device. RLM in K first BWPs of the M first BWPs includes:

averaging, by the terminal device, K measurement values that are obtained by performing RLM in the K BWPs in a first time period, to obtain a first average measurement value, where the K BWPs correspond one-to-one to the K measurement values; and

if a bit error rate obtained based on the first average measurement value is greater than a preset threshold, reporting, by the terminal device, the OOS state.

In a possible implementation, the performing, by the terminal device, RLM in K first BWPs of the M first BWPs includes:

averaging, by the terminal device, K measurement values that are obtained by performing RLM in the K BWPs in a second time period, to obtain a second average measurement value, where the K BWPs correspond one-to-one to the K measurement values; and

if a bit error rate obtained based on the second average measurement value is less than a preset threshold, reporting, by the terminal device, the IS state.

In a possible implementation, the performing, by the terminal device, RLM in K first BWPs of the M first BWPs includes:

performing, by the terminal device, RLM in the K BWPs in a third time period, to obtain K bit error rates that correspond one-to-one to the K BWPs; and

if L1 bit error rates of the K bit error rates are all greater than a preset threshold, reporting, by the terminal device, the OOS state, where L1 is an integer greater than or equal to 1, and L1 is less than or equal to K.

In a possible implementation, the performing, by the terminal device, RLM in K first BWPs of the M first BWPs includes:

performing, by the terminal device, RLM in the K BWPs in a fourth time period, to obtain K bit error rates that correspond one-to-one to the K BWPs; and

if L2 bit error rates of the K bit error rates are all less than a preset threshold, reporting, by the terminal device, the IS state, where L2 is an integer greater than or equal to 1, and L2 is less than or equal to K.

In a possible implementation, the method further includes:

receiving, by the terminal device, second indication information sent by the network device, where the second indication information is used to indicate the K BWPs, and K is less than M; and

the performing, by the terminal device, RLM in K first BWPs of the M first BWPs includes:

performing, by the terminal device, RLM in the K BWPs based on the second indication information.

According to a sixth aspect, a radio link monitoring method is provided. The method includes:

performing, by a terminal device, radio link monitoring RLM in S second bandwidth parts BWPs, where S is an integer greater than 1;

receiving, by the terminal device, first switching information sent by a network device, where the first switching information is used to indicate that active bandwidth parts BWPs include M first BWPs, and M is an integer greater than 1;

switching, by the terminal device, from the S second BWPs to the M first BWPs based on the first switching information;

receiving, by the terminal device, indication information sent by the network device, where the indication information is used to indicate the terminal device to continue to use, in a process of performing RLM in the M first BWPs, a measurement result obtained by performing RLM in the S second BWPs; and the measurement result includes a quantity N3 of at least some out of synchronization OOS states or a quantity N4 of at least some in synchronization IS states; and

performing, by the terminal device. RLM in the M first BWPs based on the measurement result.

In a possible implementation, the M first BWPs and the S second BWPs partially overlap, or the M first BWPs and the S second BWPs do not overlap.

In a possible implementation, the performing, by the terminal device, RLM in the M first BWPs based on the measurement result includes:

counting, by the terminal device starting from N3, a quantity of consecutive OOS states, where the measurement result includes the quantity N3 of at least some OOS states; or

counting, by the terminal device starting from N4, a quantity of consecutive IS states, where the measurement result includes the quantity N4 of at least some IS states.

In a possible implementation, the measurement result further includes at least partial duration T3 of total duration recorded from a time at which an RLM timer is enabled to a time at which the RLM timer is stopped; and

the performing, by the terminal device, RLM in the M first BWPs based on the measurement result includes:

starting, by the terminal device, timing from T3.

According to a seventh aspect, a radio link monitoring method is provided. The method includes:

performing, by a terminal device, radio link monitoring RLM in S second bandwidth parts BWPs, where S is an integer greater than 1:

receiving, by the terminal device, first switching information sent by a network device, where the first switching information is used to indicate that active BWPs include M first BWPs, and M is an integer greater than 1:

switching, by the terminal device, from the S second BWPs to the M first BWPs based on the first switching information;

storing, by the terminal device, a measurement result obtained by performing RLM in the S second BWPs, where the measurement result includes a quantity N3 of at least some out of synchronization OOS states or a quantity N4 of at least some in synchronization IS states;

performing, by the terminal device, RLM in the M first BWPs:

receiving, by the terminal device, second switching information sent by the network device, where the second switching information is used to indicate S1 second BWPs of the S second BWPs, and S1 is an integer greater than or equal to 1;

switching, by the terminal device, from the M first BWPs to the S1 second BWPs based on the second switching information; and

performing, by the terminal device, RLM in the S1 second BWPs based on the measurement result.

In a possible implementation, the performing, by the terminal device, RLM in the S second BWPs based on the measurement result includes:

counting, by the terminal device starting from N3, a quantity of consecutive OOS states, where the measurement result includes the quantity N3 of at least some OOS states; or

counting, by the terminal device starting from N4, a quantity of consecutive IS states, where the measurement result includes the quantity N4 of at least some IS states.

In a possible implementation, the measurement result further includes at least partial duration T3 of total duration recorded from a time at which an RLM timer is enabled to a time at which the RLM timer is stopped; and

the performing, by the terminal device, RLM in the S1 second BWPs based on the measurement result includes:

starting, by the terminal device, timing from T3.

According to an eighth aspect, a radio link monitoring method is provided. The method includes:

sending, by a network device, indication information to a terminal device, where the indication information is used to indicate the terminal device to remove, in a process of performing RLM in a first BWP included in an active bandwidth part, a measurement result obtained by the terminal device by performing RLM in a second BWP; and the measurement result includes a quantity N1 of at least some out of synchronization OOS states or a quantity N2 of at least some in synchronization IS states.

According to a ninth aspect, a radio link monitoring method is provided. The method includes:

sending, by a network device, first switching information to a terminal device, where the first switching information is used to indicate that an active bandwidth part BWP includes a first BWP; and

sending, by the network device, indication information to the terminal device, where the indication information is used to indicate the terminal device to continue to use, in a process of performing RLM in the first BWP, a measurement result obtained by performing RLM in a second BWP; and the measurement result includes a quantity N1 of at least some out of synchronization OOS states or a quantity N2 of at least some in synchronization IS states.

According to a tenth aspect, a radio link monitoring method is provided. The method includes:

sending, by a network device, first indication information to a terminal device, where the first indication information is used to indicate that active bandwidth parts BWPs include M BWPs, and M is an integer greater than 1.

In a possible implementation, the method further includes:

sending, by the network device, second indication information to the terminal device, where the second indication information is used to indicate K BWPs, and K is less than M.

According to an eleventh aspect, a radio link monitoring apparatus is provided. The apparatus may be configured to perform operations of the terminal device according to any one of the first aspect to the seventh aspect or the possible implementations of the first aspect to the seventh aspect. Specifically, the apparatus may include modules or units configured to perform the operations of the terminal device according to any one of the possible implementations of the first aspect to the seventh aspect.

According to a twelfth aspect, a radio link monitoring apparatus is provided. The apparatus may be configured to perform operations of the network device according to any one of the eighth aspect to the tenth aspect or the possible implementations of the eighth aspect to the tenth aspect. Specifically, the apparatus may include modules or units configured to perform the operations of the network device according to any one of the possible implementations of the eighth aspect to the tenth aspect.

According to a thirteenth aspect, a terminal device is provided. The terminal device includes a processor, a transceiver, and a memory. The processor, the transceiver, and the memory communicate with each other through an internal connection path. The memory is configured to store an instruction, and the processor is configured to execute the instruction stored in the memory. When the processor executes the instruction stored in the memory, the execution enables the terminal device to perform the method according to any one of the possible implementations of the first aspect to the seventh aspect, or the execution enables the terminal device to implement the apparatus according to the eleventh aspect.

According to a fourteenth aspect, a network device is provided. The network device includes a processor, a transceiver, and a memory. The processor, the transceiver, and the memory communicate with each other through an internal connection path. The memory is configured to store an instruction, and the processor is configured to execute the instruction stored in the memory. When the processor executes the instruction stored in the memory, the execution enables the network device to perform the method according to any one of the possible implementations of the eighth aspect to the tenth aspect, or the execution enables the network device to implement the apparatus according to the twelfth aspect.

According to a fifteenth aspect, a chip system is provided. The chip system includes a memory and a processor. The memory is configured to store a computer program, and the processor is configured to invoke the computer program from the memory and run the computer program, so that a communications device in which the chip system is installed performs the method according to any one of the first aspect to the tenth aspect or the possible implementations of the first aspect to the tenth aspect.

According to a sixteenth aspect, a computer program product is provided. The computer program product includes computer program code. When the computer program code is run by a communications unit, a processing unit, a transceiver, or a processor of a communications device (for example, a network device or a terminal device), the communications device is enabled to perform the method according to any one of the first aspect to the tenth aspect or the possible implementations of the first aspect to the tenth aspect.

According to a seventeenth aspect, a computer-readable storage medium is provided. The computer-readable storage medium stores a program, and the program enables a communications device (for example, a network device or a terminal device) to perform the method according to any one of the first aspect to the tenth aspect or the possible implementations of the first aspect to the tenth aspect.

According to an eighteenth aspect, a computer program is provided. When the computer program is executed on a computer, the computer is enabled to implement the method according to any one of the first aspect to the tenth aspect or the possible implementations of the first aspect to the tenth aspect.

In some of the foregoing implementations, the method further includes:

receiving, by the terminal device, third indication information sent by the network device, where the third indication information is used to indicate L1.

In some of the foregoing implementations, the method further includes: receiving, by the terminal device, third indication information sent by the network device, where the third indication information is used to indicate L2.

