AU2018314063B2

AU2018314063B2 - Method and apparatus for handling radio link failure in system using multiple reference signals

Info

Publication number: AU2018314063B2
Application number: AU2018314063A
Authority: AU
Inventors: June Hwang; Byounghoon JUNG; Hyunjeong Kang; Jungmin Moon; Seunghoon Park
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2017-08-10
Filing date: 2018-08-10
Publication date: 2022-12-22
Anticipated expiration: 2038-08-10
Also published as: CN111034295A; AU2018314063A1; KR20190017620A; EP3653009A4; EP3653009A1; CN111034295B

Abstract

A communication method and a system for converging a 5th-generation (5G) communication system for supporting higher data rates beyond a 4th-generation (4G) system with a technology for internet of things (IoT) are provided. The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. The method includes receiving a radio resource control (RRC) message including first information associated with a reference signal for a radio link monitoring (RLM) and second information associated with a threshold for the RLM, monitoring a radio link quality of at least one reference signal indicated by the first information, comparing the radio link quality of the at least one reference signal with the threshold and indicating an in-sync or an out-of-sync to a higher layer of the terminal based on the comparison result.

Description

METHOD AND APPARATUS FOR HANDLING RADIO LINK FAILURE IN SYSTEM USING MULTIPLE REFERENCE SIGNALS

Technical Field

The disclosure relates to an event for detecting a radio link failure in the mmWave

system.

Background

To meet the demand for wireless data traffic having increased since deployment of

4th-generation (4G) communication systems, efforts have been made to develop an improved

5th-generation (5G) or pre-5G communication system. Therefore, the 5G or pre-5G

communication system is also called a 'Beyond 4G Network' or a 'Post long term evolution

(LTE) System'. The 5G communication system is considered to be implemented in higher

frequency (mmWave) bands, e.g., 60GHz bands, so as to accomplish higher data rates. To

decrease propagation loss of the radio waves and increase the transmission distance, the

beamforming, massive multiple-input multiple-output (MIMO), full dimensional MIMO

(FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques are

discussed in 5G communication systems. In addition, in 5G communication systems,

development for system network improvement is under way based on advanced small cells,

cloud radio access networks (RANs), ultra-dense networks, device-to-device (D2D)

communication, wireless backhaul, moving network, cooperative communication, coordinated

multi-points (CoMP), reception-end interference cancellation and the like. In the 5G system,

hybrid frequency-shift keying (FSK) and quadrature amplitude modulation (QAM) modulation

(FQAM) and sliding window superposition coding (SWSC) as an advanced coding modulation

19220702_1 (GHMatters) P112443.AU

(ACM), and filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and

sparse code multiple access (SCMA) as an advanced access technology have been developed.

The internet, which is a human centered connectivity network where humans generate

and consume information, is now evolving to the internet of things (IoT) where distributed

entities, such as things, exchange and process information without human intervention. The

internet of everything (IoE), which is a combination of the IoT technology and the Big Data

processing technology through connection with a cloud server, has emerged. As technology

elements, such as "sensing technology", "wired/wireless communication and network

infrastructure", "service interface technology", and "Security technology" have been demanded

for IoT implementation, a sensor network, a machine-to-machine (M2M) communication,

machine type communication (MTC), and so forth have been recently researched. Such an IoT

environment may provide intelligent internet technology services that create a new value to

human life by collecting and analyzing data generated among connected things. IoT may be

applied to a variety of fields including smart home, smart building, smart city, smart car or

connected cars, smart grid, health care, smart appliances and advanced medical services through

convergence and combination between existing information technology (IT) and various

industrial applications.

In line with this, various attempts have been made to apply 5G communication systems

to IoT networks. For example, technologies such as a sensor network, machine type

communication (MTC), and machine-to-machine (M2M) communication may be implemented

by beamforming, MIMO, and array antennas. Application of a cloud radio access network

(RAN) as the above-described big data processing technology may also be considered to be as an

19220702_1 (GHMatters) P112443.AU example of convergence between the 5G technology and the IoT technology.

Meanwhile, a radio link failure (RLF) may be found as follows. In the case of LTE,

the downlink (DL) signal is monitored based on the cell-specific reference signal (CRS). The

signal strength corresponding to the time-frequency location of the cell-specific reference signal

is measured for a preset time and is averaged over the preset time. If the average value is less

than a given signal-to-interference-plus-noise ratio (SINR) or signal-to-noise-ratio (SNR),

occurrence of a DL radio link problem is notified to the higher layers.

In radio link failure handling, unlike radio resource management (RRM) beam

management for scheduling fast beam tracking and cell mobility, whether the state of a link to

the corresponding cell is acceptable is determined in a more extended period of time, and if the

link state is not acceptable, the process of attaching to the cell itself is retried. In general, as the

process of reattaching to the cell requires performing cell search and random access channel

(RACH) and security related operations again, both radio processing and core network (CN)

processing are required. It is also necessary to exchange data between the newly attached cell

and the previous cell having caused a failure. Considering the cost of the radio resource control

(RRC) reestablishment process, it is common to give a long monitoring time as possible.

In the case of omnidirectional radiation, when measuring the strength of the

time-frequency resource of the CRS, the effects of multipath are all taken into account. When

the signal strength is measured, factors affecting directionality have already been considered.

Hence, only time factors (measurement duration, arithmetic mean, or moving average) may

affect the measurement variation.

The above information is presented as background information only to assist with an

19220702_1 (GHMatters) P112443.AU understanding of the disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the disclosure.

Summary of Invention

In the case of the mmWave system, as all terminals in the cell coverage should perform

radio link measurement, the reference signal (RS) should be transmitted through an analog beam

instead of omnidirectional transmission. Depending on the situation of the system, multiple

analog beams can be transmitted simultaneously, or one analog beam can be transmitted at a

time. There may be an RS in the scheduled beam, and there may be a measurement time slot

containing a separate measurement signal. Compared with the case of omnidirectional

radiation, the directionality is another parameter affecting radio link failure (RLF) determination.

Accordingly, an embodiment of the disclosure newly defines an event for notifying a

radio link problem to the higher layer through a combination of the directionality parameter

indicated by a specific analog beam and the time parameter.

Aspects will be set forth in part in the description which follows and, in part, will be

apparent from the description, or may be learned by practice of the presented embodiments.

In accordance with an aspect of the disclosure, a method performed by a terminal in a

wireless communication system is provided. The method includes:

transmitting, to a base station, capability information for identifying a number of

reference signals for a radio link monitoring (RLM);

receiving, from the base station, a radio resource control (RRC) message for a primary

cell (PCell) configuration including configuration information of a reference signal for the RLM

and threshold information for the RLM, wherein the reference signal for the RLM is configured

19220702_1 (GHMatters) P112443.AU for each active bandwidth part (BWP) of a cell; monitoring a radio link quality of the reference signal in an active BWP of the cell, wherein the radio link quality relates to a reception strength of the reference signal; comparing the radio link quality of the reference signal with a first threshold for an in-sync or a second threshold for an out-of-sync, wherein the first threshold and the second threshold are identified based on the threshold information for the RLM, wherein the threshold information includes a block error rate (BLER) threshold pair index corresponding to the first threshold for the in-sync and the second threshold for the out-of-sync; indicating the in-sync to a higher layer of the terminal, in case that the radio link quality of the reference signal is greater than the first threshold during afirst predetermined duration based on the configuration information of the reference signal for the RLM; and indicating the out-of-sync to the higher layer of the terminal in case that all radio link quality of the reference signal is lower than the second threshold during a second predetermined duration based on the configuration information of the reference signal for the RLM, wherein the number of reference signals for the RLM that can be simultaneously monitored by the terminal are indicated by the capability information.

In accordance with another aspect of the disclosure, a method performed by a base

station in a wireless communication system is provided. The method includes:

receiving, from a terminal, capability information for identifying a number of reference

signals for a radio link monitoring (RLM);

transmitting, to the terminal, a radio resource control (RRC) message for a primary cell

(PCell) configuration including configuration information of a reference signal for the RLM and

19220702_1 (GHMatters) P112443.AU threshold information for the RLM, wherein the reference signal for the RLM is configured for each active bandwidth part (BWP) of a cell; and transmitting the reference signal including at least one of: a synchronization signal block

(SSB); a channel state information - reference signal (CSI-RS),

wherein a first threshold for an in-sync and a second threshold for an out-of-sync are

identified based on the threshold information for the RLM, wherein the threshold information

includes a block error rate (BLER) threshold pair index corresponding to the first threshold for

the in-sync and the second threshold for the out-of-sync,

wherein, in case that a radio link quality of the reference signal is greater than the first

threshold during a first predetermined duration based on the configuration information of the

reference signal for the RLM, the in-sync is indicated to the higher layer of the terminal,

wherein, in case that all radio link quality of the reference signal are lower than the

second threshold during a second predetermined duration based on the configuration information

of the reference signal for the RLM, the out-of-sync is indicated to the higher layer of the

terminal, and

wherein the number of reference signals for the RLM that can be simultaneously

monitored by the terminal are indicated by the capability information.

In accordance with another aspect of the disclosure, a terminal in a wireless

communication system is provided. The terminal includes:

a transceiver; and

at least one processor configured to control the terminal to:

transmit, to a base station via the transceiver, capability information for

19220702_1 (GHMatters) P112443.AU identifying a number of reference signals for a radio link monitoring (RLM), receive, from the base station via the transceiver, a radio resource control (RRC) message for a primary cell (PCell) configuration including configuration information of a reference signal for the RLM and threshold information for the RLM, wherein the reference signal for the RLM is configured for each active bandwidth part (BWP) of a cell, monitor a radio link quality of the reference signal in an active BWP of the cell, wherein the radio link quality relates to a reception strength of the reference signal, compare the radio link quality of the reference signal with a first threshold for an in-sync or a second threshold for an out-of-sync, wherein the first threshold and the second threshold are identified based on the threshold information for the RLM, wherein the threshold information includes a block error rate (BLER) threshold pair index corresponding to the first threshold for the in-sync and the second threshold for the out-of-sync, indicate the in-sync to a higher layer of the terminal, in case that the radio link quality of the reference signal is greater than the first threshold during afirst predetermined duration based on the configuration information of the reference signal for the RLM, and indicate the out-of-sync to the higher layer of the terminal in case that all radio link quality of the reference signal is lower than the second threshold during a second predetermined duration based on the configuration information of the reference signal for the

RLM,

wherein the number of reference signals for the RLM that can be simultaneously

monitored by the terminal are indicated by the capability information.

In accordance with another aspect of the disclosure, a base station in a wireless

19220702_1 (GHMatters) P112443.AU communication system is provided. The base station includes: a transceiver; and at least one processor configured to control the base station to: receive, from a terminal via the transceiver, capability information for identifying a number of reference signals for a radio link monitoring (RLM), transmit, to the terminal via the transceiver, a radio resource control (RRC) message for a primary cell (PCell) configuration including configuration information of a reference signal for the RLM and threshold information for the RLM, wherein the reference signal for the RLM is configured for each active bandwidth part (BWP) of a cell, and transmit the reference signal including at least one of: a synchronization signal block (SSB); a channel state information - reference signal (CSI-RS), wherein a first threshold for an in-sync and a second threshold for an out-of-sync are identified based on the threshold information for the RLM, wherein the threshold information includes a block error rate (BLER) threshold pair index corresponding to the first threshold for the in-sync and the second threshold for the out-of-sync, wherein, in case that a radio link quality of the reference signal is greater than the first threshold during a first predetermined duration based on the configuration information of the reference signal for the RLM, the in-sync is indicated to the higher layer of the terminal, wherein, in case that all radio link quality of the reference signal are lower than the second threshold during a second predetermined duration based on the configuration information of the reference signal for the RLM, the out-of-sync is indicated to the higher layer of the terminal, and

19220702_1 (GHMatters) P112443.AU wherein the number of reference signals for the RLM that can be simultaneously monitored by the terminal are indicated by the capability information.

Advantageous Effects of Invention

In a feature of the disclosure, it is possible to define an event notifying a radio link

problem by use of a scheme for out-of-sync and in-sync determination based on a reference

signal (RS).

Other aspects, advantages, and salient features of the disclosure will become apparent to

those skilled in the art from the following detailed description, which, taken in conjunction with

the annexed drawings, discloses various embodiments of the disclosure.

Brief Description of Drawings

The above and other aspects, features, and advantages of certain embodiments of the

disclosure will be more apparent from the following description taken in conjunction with the

accompanying drawings, in which:

FIG. 1 illustrates a measurement slot according to an embodiment of the disclosure;

FIG. 2 illustrates a case where a measurement value for a beam scheduled in addition to

the measurement in the measurement slot is added as a sample for a given time duration

according to an embodiment of the disclosure;

FIG. 3 illustrates transmission of a synchronization signal (SS) simultaneously using

multiple data TX beams according to an embodiment of the disclosure;

FIG. 4 illustrates a case where, for the report of the sequential SS measurement results,

the base station configures a separate reference signal for the data TX beams constituting the

corresponding SS and transmits the reference signal together with the configuration information

19220702_1 (GHMatters) P112443.AU to the terminal according to an embodiment of the disclosure;

FIG. 5 illustrates the difference in radio link monitoring (RLM) operation between long

term evolution (LTE) and new radio (NR) operating beams according to an embodiment of the

disclosure;

FIG. 6 depicts signaling between the terminal and the base station to utilize the xSS for

radio link monitoring according to an embodiment of the disclosure;

FIG. 7 depicts a case where the Tin value is adaptively managed with respect to the

number of operating beams according to an embodiment of the disclosure;

FIG. 8 depicts a case where the base station transmits information on the offset value set

for a specific DL TX beam as system information and the terminal uses this information

whenever a DL TX beam set is configured according to an embodiment of the disclosure;

FIG. 9 depicts a case where beam offset information is transmitted through a radio

resource control (RRC) dedicated message according to an embodiment of the disclosure;

FIG. 10 depicts a case where related offset information is transmitted through a

physical-layer control channel according to an embodiment of the disclosure;

FIG. 11 depicts a case where related offset information is transmitted through a medium

access control (MAC) control element (CE) according to an embodiment of the disclosure;

FIG. 12 illustrates a scheme where the physical layer provides a per-RS indication or an

aggregate indication to the higher layer (RRC) according to an embodiment of the disclosure;

FIG. 13 illustrates a case where the channel state information-reference signal (CSI-RS)

is in-sync (IS) for the terminal but the related SS is not in-sync according to an embodiment of

the disclosure;

19220702_1 (GHMatters) P112443.AU

FIG. 14 illustrates a policy that, when the CSI-RS is configured at a specific point in

time while performing RLM through the SS, RLM is performed with priority given to the

CSI-RS according to an embodiment of the disclosure;

FIG. 15 illustrates a policy that, when the CSI-RS is configured at a specific point in

CSI-RS according to an embodiment of the disclosure;

FIG. 16 depicts a case where the base station configures a specific bandwidth part

(BWP) on the basis of the capabilities and service requirements of the terminal according to an

embodiment of the disclosure;

FIG. 17 depicts a case where user equipment (UE) beamforming related capability

information, requested service related information, and preferred bandwidth part information are

transmitted via a separate RRC messages after connection setup according to an embodiment of

the disclosure;

FIG. 18 illustrates a case where the RLM-RS is present only in one frequency range

according to an embodiment of the disclosure;

FIG. 19 depicts RLM-RS signaling when the active bandwidth part has an RLM-RS or

does not have an RLM-RS according to an embodiment of the disclosure;

FIG. 20 illustrates a case where the RLM-RS is present in multiple frequency ranges

according to an embodiment of the disclosure;

FIG. 21 is a block diagram of a base station according to an embodiment of the

disclosure.

FIG. 22 is a block diagram of a terminal according to an embodiment of the disclosure;

19220702_1 (GHMatters) P112443.AU

FIG. 23 depicts a case where RLM/RLF parameters are set differently according to the

type of a service received by the terminal according to an embodiment of the disclosure; and

FIG. 24 depicts a handover situation where the target cell receives service information of

the terminal from the serving cell and transmits correspondingly configuration information about

the RLM RS, block error rate (BLER), and RLF parameters to the serving cell according to an

embodiment of the disclosure.

Throughout the drawings, it should be noted that like reference numbers are used to

depict the same or similar elements, features, and structures.

Detailed Description of Embodiments of the Invention

The following description with reference to the accompanying drawings is provided to

assist in a comprehensive understanding of various embodiments of the disclosure as defined by

the claims and their equivalents. It includes various specific details to assist in that understanding

but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art

will recognize that various changes and modifications of the various embodiments described

herein can be made without departing from the scope and spirit of the disclosure. In addition,

descriptions of well-known functions and constructions may be omitted for clarity and

conciseness.

The terms and words used in the following description and claims are not limited to the

bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent

understanding of the disclosure. Accordingly, it should be apparent to those skilled in the art that

the following description of various embodiments of the disclosure is provided for illustration

purpose only and not for the purpose of limiting the disclosure as defined by the appended

19220702_1 (GHMatters) P112443.AU claims and their equivalents.

It is to be understood that the singular forms "a "an," and "the" include plural referents

unless the context clearly dictates otherwise. Thus, for example, reference to "a component

surface" includes reference to one or more of such surfaces.

The aspects, features and advantages of certain embodiments of the disclosure will be

more apparent from the following detailed description taken in conjunction with the

accompanying drawings. The description of the various embodiments does not describe every

possible instance of the disclosure. It should be apparent to those skilled in the art that the

following description of various embodiments is provided for illustration purpose only and not

for the purpose of limiting the present disclosure as defined by the appended claims and their

equivalents. The same reference symbols are used throughout the description to refer to the

same parts.

In the following description, the terms "base station", "enhanced node B (eNB)", and "g

node B (gNB)" may be interchangeably used. The terms "terminal" and "user equipment (UE)"

may be interchangeably used.

As a measurement source, it is possible to measure the RS in the measurement slot,

measure the reference signal (RS) of the scheduled beam, and measure the demodulation

reference signal (DMRS) on the physical downlink control channel (PDCCH). These

measurement values can be considered together. In the description, the beam measurement

reference signal (BRS) is different from the cell-specific reference signal (CRS) in that it is a

measurement RS carried by an analog beam and is used when two or more analog beams

disjointly cover the cell coverage to serve one cell. The BRS may be carried by such beams

19220702_1 (GHMatters) P112443.AU and may be used to measure the reference signal received power (RSRP), the reference signal received quality (RSRQ), or the received signal strength indication (RSSI).

[Embodiment 1: considering only the RS in the measurement slot (only the SS is

configured)]

FIG. 1 illustrates a measurement slot according to an embodiment of the disclosure.

Referring to FIG. 1, a measurement slot. In the beam sweeping slot, the gNB TX

transmits beams each including the BRS while sweeping the beam in sequence. While the gNB

is TX sweeping, the RX receives a specific beam and measures the BRS. Alternatively, when

the gNB TX repeatedly transmits a beam including the BRS, the UE may sweep the RX beam.

This method applies to the case of RS source variations proposed herein and to the case of

in-sync determination. In any case, the term during which measurement can be performed for

all combinations of TX beams and RX beams is referred to as term 1, and the specific time

below can be multiple terms.

A. [Calculation for each pair of 1 TX beam and 1 RX beam] counting the values in

different terms separately: when the N best measurement values among the measurement values

for all TX-RX beam pairs measured during a specific time are less than a preset threshold, it is

determined to be out-of-sync (OOS). Here, the measurement value in term 1 for a TX-RX

beam pair and the measurement value in term 2 for the same TX-RX beam pair are regarded as

different, and the measurement values in all terms for every beam pair are treated separately. If

the N best measurement values are less than the out-of-sync (OOS) threshold, it is determined to

be OOS.

B. [Calculation for each combination of 1 TX beam and M RX beams] counting the

19220702_1 (GHMatters) P112443.AU values in different terms separately: for each TX beam, M RX beams are selected first and the average (or linear combination) of the measurement values for the M RX beams is computed for a specific time. Here, the average value (or linear combination value) in term 1 for a TX-beam and the average value in term 2 for the same TX beam are regarded as different. If the N best values among the average values for all TX beams are less than the OOS threshold, it is determined to be OOS. Here, the value of M may be given or may be selected for each terminal based on a specific metric.

C. [Calculation for each pair of 1 TX beam and 1 RX beam] counting the values in

different terms separately: in "A" case, the average (or linear combination) of the measurement

values for the N selected beams is computed. If the average value (or linear combination value)

is less than the OOS threshold, it is determined to be OOS.

D. [Calculation for each combination of 1 TX beam and M RX beams] counting the

values in different terms separately: in "B" case, the average (or linear combination) of the N

selected values is computed. If the average value (or linear combination value) is less than the

OOS threshold, it is determined to be OOS. Here, the value of M may be given or may be

selected for each terminal based on a specific metric.

E. [Calculation for each pair of 1 TX beam and 1 RX beam] using the term-wise

average: a linear combination value of measurement values for all TX-RX beam pairs is

calculated for each term during a specific time. If none of the N best values among the

term-wise linear combination values is greater than the OOS threshold, it is determined to be

OOS. Here, the value of M may be given or may be selected for each terminal based on a

specific metric.

19220702_1 (GHMatters) P112443.AU

F. [Calculation for each combination of 1 TX beam and M RX beams] using the

term-wise average: for each TX beam, M RX beams are selected first. A linear combination of

the measurement values for the M RX beams is computed for each term during a specific time.

If none of the N best values among the term-wise linear combination values is greater than the

selected for each terminal based on a specific metric.

G. [Calculation for each pair of 1 TX beam and 1 RX beam]: in "E" case, a linear

combination of the N best values is computed. If the linear combination value is less than the

selected for each terminal based on a specific metric.

H. [Calculation for each combination of 1 TX beam and M RX beams]: in "F" case, a

linear combination of the N best values is computed. If the linear combination value is less

than the OOS threshold, it is determined to be OOS. Here, the value of M may be given or may

be selected for each terminal based on a specific metric.

[Embodiment 2: the RS is present in the scheduled analog beam in addition to the

measurement slot (the CSI-RS is configured)]

In this case, information on the RS resource location at the scheduled TX beam should

be shared in advance.

according to an embodiment of the disclosure.

Referring to FIG. 2, for a given time, the measurement value for a beam scheduled in

19220702_1 (GHMatters) P112443.AU addition to the measurement in the existing measurement slot is added as a sample. In the remaining part, the above cases (A to H) described in thefirst embodiment are directly applied.

The measurement value for the scheduled TX beam and associated RX beam and the

measurement result for the BRS are added to the case of thefirst embodiment. When

performing the calculation, the measurement value for the added pair of the TX beam and RX

beam is added to the previous calculation result.

For example, a plurality of BRSs can be simultaneously transmitted and act as a

synchronization signal (SS). A subset of the data TX beams of the base station canbe

simultaneously radiated for one SS transmission. In this case, the SS can be measured and the

measurement result can be used to find a refined TX beam, and the control and data can be

transmitted via the refined TX beam. Here, the reference signal indicating the PDCCH

hypothesis transmission may be either the SS itself or the data TX beams constituting the SS.

multiple data TX beams according to an embodiment of the disclosure.

Referring to FIG. 3, the SS is transmitted as a composite beam using multiple data TX

beams (e.g., three) simultaneously. The same synchronization signal is transmitted through

these beams, and the terminal sees the same synchronization signal in the beam coverage. By

measuring the SS transmitted through the composite beam, the terminal achieves timing

synchronization with the cell. At the same time, the terminal performs measurement to find the

data TX beam needed thereby in the composite beam.

19220702_1 (GHMatters) P112443.AU corresponding SS and transmits the reference signal together with the configuration information to the terminal according to an embodiment of the disclosure.

Referring to FIG. 4, the terminal 405 measures the SS in sequence (at operations 421,

422, 423), and reports the measurement result (e.g., the SS with the strongest received signal

strength) to the base station 410 (at operation 425). The base station 410 configures a separate

reference signal (referred to as an additional RS, abbreviated as "aRS") in the data TX beams

forming the SS and transmits this information to the terminal 405 (at operation 431). Upon

receiving the information, the terminal 405 measures the aRS in the SS (at operations 433, 434,

435) (operation 441), and reports the measurement result to the base station (at operation 443).

The base station 410 determines the beam for data/control transmission (at operation 451).

When the base station 410 transmits the determined beam indication to the terminal 405 (at

operation 453), the terminal identifies the DL TX beam indicated by the beam indication. Then,

the terminal 405 receives data/control information via the identified beam. In this process, one

or both of the SS and the aRS may be used as a reference signal for in-sync (IS)/out-of-sync

(OOS) determination. In the description, the terms "aRS" and "CSI-RS" may be

interchangeably used.

If only the SS is configured, the SS can be used instead of the BRS in OOS

determination in the first embodiment of the disclosure. The following shows the signaling of

the required information when only the SS is used.

Next, the per-beam measurement is described in another perspective.

In LTE radio link monitoring, if the Q_out threshold is not exceeded for a duration

T_out (= 200ms), an OOS indication is generated. In this case, since the RS is generated on a

19220702_1 (GHMatters) P112443.AU symbol basis in each subframe, the reception strength will be measured at different points in time and have different values measured for 200ms. Since it is a UE implementation issue to have a certain value as the representative value, various options may be possible, but most of them will assume the average value for each symbol as the representative value. In the case of in-sync, an

IS indication is generated if the Q_in threshold is exceeded for a duration Tin (= OOms).

If the xSS is set as the target for RLM, the symbol position (time and frequency) of the

xSS may be known in advance or may be notified by the network through a broadcast channel or

a dedicated signal. Based on this information, the reception strength of the xSS is measured for

each symbol. If it is known through the network information that the xSS symbols are

transmitted via one specific beam, instead of unconditionally comparing the average value of the

xSS symbols during Tout with the threshold, considering only the symbols transmitted via the

corresponding beam, the terminal may regard it as an in-sync decision element if its value is

larger than Q_in, and regard it as an out-of-sync decision element if its value is smaller than

Q out.

FIG. 5 illustrates the difference in radio link monitoring (RLM) operation between LTE

and NR (new radio) operating beams according to an embodiment of the disclosure.

Referring to FIG. 5, the difference in RLM operation between LTE and NR operating

beams is illustrated. Reference symbol 510 indicates OOS determination in LTE, and reference

symbol 520 indicates OOS determination in NR. Whether the terminal can identify the beam

carrying the xSS is examined. If the terminal cannot identify such a beam, the base station

should provide necessary information enabling the terminal to identify the beam. Here, xSSs

transmitted by one xSS block or one xSS block set may be referred to as "per-beam xSSs".

19220702_1 (GHMatters) P112443.AU

[Embodiment 2-1: only the SS is the RLM target]

More specifically, the received signal strength of the xSSs transmitted by one beam is

referred to as "reception strength of the per-beam xSSs". Here, the reception strength of the

per-beam xSSs may be the average of reception strengths of the xSSs transmitted by one beam, a

linear combination of reception strengths with specific weights, or an implementation-dependent

value. To issue an out-of-sync (OOS) indication, the terminal determines whether the reception

strength of the per-beam xSSs is greater or less than Q_out in consideration of all xSSs

transmitted during Tout. If the reception strength of the per-beam xSSs is less than Q_out for

all beams transmitted during Tout, the terminal issues an OOS indication to the higher layer.

As another example, the network may set the value of N separately to issue an OOS indication if

the reception strength of the per-beam xSSs is less than Q_out for N beams. Here,asthe

number of beams carrying the xSS may be different in different base stations, it is necessary to

more flexibly perform OOS determination. In this regard, the base station can adaptively

determine the value of T_out in relation to the number of operating beams.

Likewise, it is possible to issue an in-sync (IS) indication by use of the reception

strength of the per-beam xSSs. To issue an IS indication, the terminal determines whether the

reception strength of the per-beam xSSs is greater or less than Q_in in consideration of all xSSs

transmitted during T_in. If the reception strength of the per-beam xSSs is greater than Q_in for

any beam transmitted during Tin, the terminal issues an IS indication to the higher layer. As

another example, the network may set the value of N separately to issue an IS indication if the

reception strength of the per-beam xSSs is greater than Q_in for N beams. Here, as the number

of beams carrying the xSS may be different in different base stations, it is necessary to more

19220702_1 (GHMatters) P112443.AU flexibly perform IS determination. In this regard, the base station can adaptively determine the value of T_in in relation to the number of operating beams.

radio link monitoring according to an embodiment of the disclosure.

FIG. 6 depicts signaling of the base station to transmit parameters needed for utilizing

the xSS for radio link monitoring.

At operation 620, the base station 610 may transmit parameters needed for RLM to the

terminal605. The base station 610 may notify the terminal 605 of SS configuration

information and RLM/RLF parameters (number of beams needed for OOS and IS determination,

threshold information needed for OOS and IS determination, duration required for generating

one OOS indication (Tout), duration required for generating one IS indication (Tin), RLF

timer value, number of consecutive OOS and IS indications required to start and stop the RLF

timer). The base station 610 may notify the terminal 605 of the RLM/RLF parameters through

system information, broadcast signaling, or UE dedicated signaling. The terminal 605 may

have in advance at least one of the RLM/RLF parameters as a default value. For a RLM/RLF

parameter that is not configured by the base station 610, the terminal 605 can use the

corresponding default value. When a RLM/RLF parameter is newly configured, the terminal

605 can use the updated parameter.

The xSS configuration information may include the beam ID of a beam carrying an SS

to be measured for RLM (or corresponding time, frequency, and resource information), or the SS

location information on the time and frequency of the SS resource to be measured in the

corresponding beam. Tout or T_in is the time duration required for generating one OOS or IS

19220702_1 (GHMatters) P112443.AU indication. N is used to specify the number of beams for a case where the measurement result is higher than the threshold among the per-beam measurement results during one Tout or T_in.

That is, in the case of OOS determination, if the measurement result is above the threshold for N

or more beams, this is not OOS. In the case of IS determination, if the measurement result is

above the threshold for N or more beams, this is IS. The RLF timer value, and the number of

consecutive OOS and IS indications required to start and stop the RLF timer may also be

transmitted as a parameter. If the xSSs belong to a band of one numerology, the necessary

information can be transmitted at once without additional configuration in the connected state as

shown in FIG. 6. When the xSSs span a band with multiple numerologies with respect to the

cell, if the terminal 605 can access a limited number of bandwidth parts (BWP) at a time and the

BWPs can have different numerologies, the parameters described above for the active BWP

assigned to the terminal 605 may be transmitted via a UE dedicated message. The base station

610 transmits xSSblock signals to the terminal 605 (at operations 631, 632, 633, 634).

Specifically for the thresholds, the base station can transmit the terminal a threshold

value (RSRP, RSRQ, signal-to-interference-plus-noise ratio (SINR), or RSSI) corresponding to a

given BLER for the measurement result of the RS to measure the xSSblock signals specified for

hypothetical PDCCH transmission at the physical layer. Alternatively, the target BLER for a

hypothetical PDCCH transmission can be delivered to the terminal. Upon receiving this value,

as the terminal is aware of the relationship between the xSSblock signal measurement value and

the given BLER, the terminal measures the xSSblock with respect to the given BLER to generate

an OOS or IS indication (at operation 640). Additionally, the base station may deliver a

randomly selected threshold or BLER value, or may deliver a value selected from a pre-defined

19220702_1 (GHMatters) P112443.AU set of threshold or BLER values.

In this case, the OOS indication and the IS indication can be generated independently

according to their conditions. There may be a minimum time gap between OOS/IS indications

due to UE signaling overhead or implementation difficulty.

[Embodiment 2-2: the CSI-RS becomes the RLM target]

If the CSI-RS is used for radio link monitoring, the received signal strength of the

CSI-RSs included in the beam carrying the CSI-RS instead of the xSS is compared with the

threshold for OOS or IS determination. Here, the CSI-RS may be terminal specific or cell

specific. In any case, the base station must transmit the CSI-RS configuration information to

the terminal. The CSI-RS configuration may be periodic or aperiodic event driven. The

terminal should know whether the configured CSI-RS belongs to a specific beam. If the

terminal knows the mapping between the beam and the CSI-RS, the terminal may consider the

reception strength of the per-beam CSI-RSs as in the case of the xSS described before. Here,

the reception strength of the per-beam CSI-RSs corresponds to the average (or, linear

combination) of the received signal strengths of the CSI-RSs transmitted by the corresponding

beam.

To issue an out-of-sync (OOS) indication, the terminal determines whether the reception

strength of the per-beam CSI-RSs is greater or less than Q_out in consideration of all CSI-RSs

transmitted during Tout. If the reception strength of the per-beam CSI-RSs is less than Q_out

for all beams transmitted during Tout, the terminal issues an OOS indication to the higher layer.

the reception strength of the per-beam CSI-RSs is less than Q_out for N beams. Here,asthe

19220702_1 (GHMatters) P112443.AU number of beams carrying the CSI-RS may be different in different base stations, it is necessary to more flexibly perform OOS determination. In this regard, the base station can adaptively determine the value of T_out in relation to the number of operating beams.

strength of the per-beam CSI-RSs. To issue an IS indication, the terminal determines whether

the reception strength of the per-beam CSI-RSs is greater or less than Q_in in consideration of

all CSI-RSs transmitted during Tin. If the reception strength of the per-beam CSI-RSs is

greater than Q_in for any beam transmitted during Tin, the terminal issues an IS indication to

the higher layer. As another example, the network may set the value of N separately to issue an

IS indication if the reception strength of the per-beam CSI-RSs is greater than Q_in for N beams.

Here, as the number of beams carrying the CSI-RS may be different in different base stations, it

is necessary to more flexibly perform IS determination. In this regard, the base station can

adaptively determine the value of Tin in relation to the number of operating beams as shown in

FIG. 7. To this end, information on the RLF timer value and the number of consecutive OOS

and IS indications required to start and stop the RLF timer may be delivered as a parameter.

number of operating beams according to an embodiment of the disclosure. In particular,

whenever the UE specific CSI-RS is newly configured, the base station may notify the

RLM-related parameters together with the CSI-RS configuration information. At operation 720,

the base station 710 may transmit parameters needed for RLM to the terminal 705.

Referring to FIG. 7, when the CSI-RS is configured, the base station 710 notifies the

terminal 705 of the CSI-RS configuration information (ID of configured CSI-RS, or beam

19220702_1 (GHMatters) P112443.AU time-frequency information and resource location information) and RLM/RLF parameters

(number of beams needed for OOS and IS determination, threshold information needed for OOS

and IS determination, duration required for generating one OOS indication (Tout), duration

required for generating one IS indication (Tin), RLF timer value, number of consecutive OOS

and IS indications required to start and stop the RLF timer). The base station 710 may notify

the terminal 705 of the RLM/RLF parameters through system information, broadcast signaling,

or UE dedicated signaling. The terminal 705 may have in advance at least one of the

RLM/RLF parameters as a default value. For a RLM/RLF parameter that is not configured by

the base station 710, the terminal 705 can use the corresponding default value. Whena

RLM/RLF parameter is newly configured, the terminal 705 can use the updated parameter. If

the terminal 705 can access a limited number of bandwidth parts (BWP) at a time, the BWPs can

have different numerologies, and different CSI-RS settings may be given accordingly. The

parameters described above for the active BWP assigned to the terminal 705 may be transmitted

via a UE dedicated message. That is, in FIG. 7, if the CSI-RS configuration changes in the

same BWP, it may be applied at the time of reconfiguration. If the CSI-RS is configured to use

another BWP, the information given in FIG. 7 may be carried by a message notifying the

corresponding BWP. Alternatively, if the CSI-RS is configured to use another BWP, the

information given in FIG. 7 may be carried by a dedicated message after the terminal accesses

the corresponding BWP. The base station 710 transmits CSI-RSs to the terminal 705 (at

operations 731, 732, 733, 734).

Specifically for the thresholds, the base station 710 can transmit the terminal 705 a

threshold value (RSRP, RSRQ, SINR, or RSSI) corresponding to a given BLER for the

19220702_1 (GHMatters) P112443.AU measurement result of the RS to measure the CSI-RS signals specified for hypothetical PDCCH transmission at the physical layer. Alternatively, the target BLER for a hypothetical PDCCH transmission can be delivered to the terminal 705. Upon receiving this value, as the terminal

705 is aware of the relationship between the CSI-RS measurement value and the given BLER,

the terminal measures the CSI-RSs with respect to the given BLER to generate an OOS or IS

indication (740). Additionally, the base station 710 may deliver a randomly selected threshold

or BLER value, or may deliver a value selected from a pre-defined set of threshold or BLER

values.

In the case where only the aRS is used, since the aRS does not occur for a uniform

period of time, the aRS is measured when downlink transmission occurs and the corresponding

beam is received. Regardless of the number of samples, if the time-average reception strength

during the most recent time period does not exceed the OOS threshold, an OOS indication is

issued; and if it exceeds the IS threshold, an IS indication is issued.

[Embodiment 2-2: both SS and CSI-RS are used for RLM]

- The RLM/RLF parameters may be different for RSs

For the SS, since OOS/IS must be determined through beam sweeping with a wide beam

in all directions, the T_out/Tin time window will be larger than that for the CSI-RS using a

narrow beam. The CSI-RS beam is not any available narrow beam but is a small number of

beams allocated by the base station to the data and control channels, so that T_out/Tin for the

CSI-RS is often small depending on the number of beams. As an opportunity to check whether

the current situation is in-sync or out-of-sync, the T_out/T-in time window can be different for

the SS and the CSI-RS during the same time period. When the channel condition becomes poor,

19220702_1 (GHMatters) P112443.AU considering the same number of times of waiting for the SS or the CSI-RS, the RLF time value will be large for the SS and be small for the CSI-RS.

- When the two RSs issues the same indication to the RRC (i.e., N is considered only

between RSs of the same type):

Both the xSS and the CSI-RS may be used for radio link monitoring at the same time.

In this case, RS configuration information and the OO/IS threshold can be set separately for the

xSS and the CSI-RS. The values of T_out, T_in, and N in OO/IS determination may be set

separately or may be set as one value for the xSS and the CSI-RS. The timer value or the

number of consecutive indications can also be set separately for the xSS and the CSI-RS. If all

parameter values are set separately for the xSS and the CSI-RS, the OO/IS indication can be

generated independently of the RS. Here, when the RLF timer is activated in the RRC, this

indication is recognized as the same indication regardless of the RS. In other words, if an OOS

indication is generated first from the xSS and another OOS indication is generated next from the

CSI-RS, the RRC may regard the two OOS indications as the same type of indication and

recognize them as consecutive OOS indications as in the case of LTEN310. Likewise,evenif

IS indications occur from separate settings, the RRC may recognize them as the same type of

indication.

- When the two RSs issues a unified indication to the RRC (i.e., N is considered from a

unified RS perspective):

For OOS handling, the values of T_out, T_in, and N in OOS/IS determination may be

set in a unified way for the xSS and the CSI-RS. In this case, considering both the CSI-RS

beam and the xSS beam received during Tout, if the reception strength of the per-beam RSs

19220702_1 (GHMatters) P112443.AU

(here, RS can be xSS or CSI-RS) for N beams is less than Q_out, an OOS indication is generated.

Here, the OOS threshold can be set separately for the xSS and the CSI-RS, and the values of N

and T_out are the same regardless of the RS type.

For IS handling, the values of T_out, T_in, and N in OOS/IS determination may be set in

a unified way for the xSS and the CSI-RS. In this case, considering both the CSI-RS beam and

the xSS beam received during Tin, if the reception strength of the per-beam RSs (here, RS can

be xSS or CSI-RS) for N beams is greater than Q_in, an IS indication is generated. Here, the IS

threshold can be set separately for the xSS and the CSI-RS, and the values of N and Tin are the

same regardless of the RS type.

a. Averaging measurement values of two RSs before OOS/IS determination

If both the SS and the aRS are used, the SS sample is accumulated using the BRS OOS

determination method of the disclosure, and the aRS sample is further accumulated to the

cumulative SS value when the aRS is transmitted and measured. Here, for accumulation, the

measurement value for the aRS is linearly combined with the cumulative value for the SS.

- Prioritization when multiple RSs are configured simultaneously

If two RSs are configured for RLM, the network can signal which RS has priority.

Then, an OOS or IS indication can be sent to the RRC according to the measurement result for

the RS having priority at the time of signaling. Alternatively, without giving priority to a

particular RS, it is possible to send an OOS or IS indication to the RRC by referring to the

measurement result for one RS depending upon the measurement result for the other RS. Such

a hierarchical scheme is described below.

1) Giving priority to OOS determination for SS

19220702_1 (GHMatters) P112443.AU

As another way to use the SS and the aRS together, it is possible to make a hierarchical

decision. If it is determined to be OOS on the basis of measurement values for the SS only, an

OOS indication is sent to the RRC without further consideration of the aRS. If it is determined

to be IS on the basis of measurement values for the SS only, measurement values for the aRS are

further considered. That is, if the measurement result for the aRS is less than or equal to the

given threshold, an OOS indication is sent to the RRC and otherwise an IS indication is sent to

the RRC. In this case, the measurement values for the aRS are linearly combined with each

other, and the measurement values for the SS are accumulated between the SS measurement

values as in the first BRS OOS determination scheme of the disclosure.

2) Giving priority to IS determination for SS

If it is determined to be IS on the basis of measurement values for the SS only, an IS

indication is sent to the RRC without further consideration of the aRS. If it is determined to be

OOS on the basis of measurement values for the SS only, measurement values for the aRS are

values as in the first BRS OOS determination scheme of the disclosure.

3) Giving priority to OOS determination for CSI-RS

If it is determined to be OOS on the basis of measurement values for the CSI-RS only,

an OOS indication is sent to the RRC without further consideration of the SS. If it is

determined to be IS on the basis of measurement values for the CSI-RS only, measurement

19220702_1 (GHMatters) P112443.AU values for the SS are further considered. That is, if the measurement result for the SS is less than or equal to the given threshold, an OOS indication is sent to the RRC and otherwise an IS indication is sent to the RRC. In this case, the measurement values for the aRS are linearly combined with each other, and the measurement values for the SS are accumulated between the

SS measurement values as in the first BRS OOS determination scheme of the disclosure.

4) Giving priority to IS determination for CSI-RS

If it is determined to be IS on the basis of measurement values for the CSI-RS only, an

IS indication is sent to the RRC without further consideration of the SS. If it is determined to

be OOS on the basis of measurement values for the CSI-RS only, measurement values for the SS

are further considered. That is, if the measurement result for the SS is less than or equal to the

values as in the first BRS OOS determination scheme of the disclosure.

5) Indexing scheme

For the hierarchical method described above, an index may be assigned to each

combination in advance and the network may specify a corresponding rule. Such an example is

shown in Table 1 below.

[table 1]

Index Result 1st check 2nd check Example 1 OOS SSOOS CSI-RS 5-1 oS 2 IS SSIS CSI-RS IS 5-2

19220702_1 (GHMatters) P112443.AU

If the 1st check for a particular RS produces the indicated outcome, an OOS indication is

unconditionally generated. If the 1st check does not produce the indicated outcome, the 2nd

check is considered. If the 2nd check produces the indicated outcome, an OOS indication is

generated again. Otherwise, the complementary result of being OOS is generated. When the

base station delivers this information, the terminal determines the cell-wise RLM result based on

the RLM results of the two RSs by use of the received information and notifies the cell-wise

RLM result to the RRC.

6) Delivering offset as threshold when two RSs simultaneously configured

When two RSs are used simultaneously, the threshold for each RS may be an absolute

value. However, it is also possible that one threshold is an absolute value and the other

threshold is an offset value.

When the base station transmits the terminal a parameter set corresponding to each RS,

thresholds may be given as an absolute value. If the threshold for one RS is already given, the

threshold for the other RS may be provided as an offset relative to the threshold already given.

For example, when the aRS and the SS are used simultaneously, they are different in beam width

and number of component beams. Hence, to add a measurement value for the aRS reception

beam to a measurement value for the SS reception beam, or to make a determination based on a

specific threshold, an offset to be added to the received signal strength may be needed. This

offset can be added to a measurement value for the aRS to generate a received signal strength

value for the SS serving as a unified metric. This unified metric may be compared with the

given threshold. To this end, the base station may deliver a necessary offset value to the

terminal.

19220702_1 (GHMatters) P112443.AU

whenever a DL TX beam set is configured according to an embodiment of the disclosure.

Referring to FIG. 8, an offset value is set for a specific DL TX beam, the base station

810 transmits the offset information as system information, and the terminal 805 applies this

information whenever a DL TX beam set is configured. The base station 810 transmits the

offset value as system information to the terminal 805 (at operation 821), and the base station

810 transmits the SSs in time or frequency sequence in always-on mode (at operation 823).

When the terminal 805 measures the SSs and reports the best SS to the base station 810, the base

station 810 configures an aRS at the DL TX beams constituting the best SS and transmits aRS

location information to the terminal 805 (at operation 825). The terminal 805 performs

measurement based on this information and transmits the measurement result to the base station

810. Then, the base station selects the DL TX beam (at operation 827). Here,whenthe

number of beams selected for DL transmission and the corresponding beam IDs are known, it is

possible to identify the offset value to be applied when a particular beam is measured. After

finding a new beam (at operation 829), if the DL TX beam is changed (at operation 831) while

calculating the aRS metric, based on the corresponding indication, the target for aRS metric

calculation should be changed from beam set 1 to beam set 2 (at operation 833).

19220702_1 (GHMatters) P112443.AU

Table 2 below shows an example of representing such related information.

[table 2]

xSS1 xSS2 The number 1 2 3 4 of selected Tx beams/beam ID 1 -1OdBm -1OdBm -1OdBm -1OdBm 2 -5dBm -5dBm -5dBm -5dBm 3 -3dBm -3dBm -3dBm -3dBm 4 OdBm OdBm OdBm OdBm

When two DL TX beams (beam 1 and beam 2) are selected, the value obtained by

adding -5dBM to a measurement value for beam 1 or beam 2 may be linearly combined with a

measurement value for the SS.

As another example of signaling, the above information can be delivered through an

RRC dedicated message.

FIG. 9 depicts a case where beam offset information is transmitted through an RRC

dedicated message according to an embodiment of the disclosure.

The base station 910 may transmit the offset information, which is transmitted via

system information in FIG. 8, via an RRC dedicated message, and the terminal 905 applies this

information. Since the best SS has already been determined, offset values for the DL TX

beams corresponding to the best SS can be transmitted. For example, if SS1 is selected and

reported as the best SS, the base station may provide offset values for the DL TX beams

corresponding to SS1 as shown in Table 3 below. For operations 921 to 931 except for

operation 925, refer to the corresponding operations in FIG. 8.

19220702_1 (GHMatters) P112443.AU

[table 3]

xSS1 The number of 1 2 selected Tx beams/ beam ID 1 -lOdBm -lOdBm 2 -5dBm -5dBm 3 -3dBm -3dBm 4 OdBm OdBm

physical-layer control channel according to an embodiment of the disclosure.

Referring to FIG. 10, this embodiment can send offset information faster than other

layers. For example, the base station 1010 may notify the terminal 1005 of the selected DL TX

beam through the PDCCH, and may further transmit an offset for each beam (at operation 1023).

In this case, since the base station may know the selected DL TX beams, it does not have to

transmit the offset information through downlink transmissions related to other SSs. In

addition, if the DL TX beam set is changed, the base station can quickly transmit necessary

offset information (at operation 1027). For operations 1021, 1025 and 1029, refer to the

corresponding operations in FIG. 8.

As another option, FIG. 11 depicts a case where related offset information is transmitted

through a MAC (medium access control) CE (control element) according to an embodiment of

the disclosure.

Referring to FIG. 11, the base station 1110 transmits related offset information to the

terminal 1105 through a MAC CE (at operations 1123, 1127). When notifying the DL TX

beam, the offset value associated with the number and IDs of the selected DL TX beams can be

19220702_1 (GHMatters) P112443.AU notified via a MAC CE. For operations 1121, 1125 and 1129, refer to the corresponding operations in FIG. 8.

When only one of the SS and the CSI-RS is the target of RLM, the parameter set for

each RS can be transmitted through system information or through dedicated signaling. When

most terminals can perform RLM using the CSI-RS and the SS and their terminal capabilities

can support the two RSs, information transmission overhead can be reduced by use of system

information.

However, a particular terminal may report a measurement result for only one of the two

RSs. If a particular bandwidth part can carry only the CSI-RS (without the SS), a terminal

operating in that bandwidth part may need information only about the CSI-RS. The CSI-RS

configuration information assigned to the active bandwidth part and the threshold information

required for RLM can also be changed by different numerologies. The bandwidth part used by

a terminal may change with time. In these cases, the base station may use UE dedicated

signaling to transmit the CSI-RS configuration information at the time when the corresponding

bandwidth part is used as described in subsection 2) and information regarding the value of N in

OOS/IS determination, thresholds (absolute value or offset), Tout, T_in, RLF timer value, and

the number of consecutive indications.

7) Applying RLF parameters when the RSs are simultaneously configured

The RLF timer can be started or stopped when consecutive OOS or IS indications are

sent from the physical layer (PHY) to the RRC. If only one RS is configured, or if only one RS

has priority over time without change although two RSs are configured, RLM and RLF

operations may be performed by inheriting the RLF parameters of the corresponding RS.

19220702_1 (GHMatters) P112443.AU

However, when plural RSs are configured, if the RLM RS is changed from the previous RS to a

new RS, it is necessary to determine whether to apply the RLF parameters associated with the

new RS after inheriting the state of the RLF parameters associated with the previous RS, or

whether to apply the RLF parameters associated with the new RS after resetting the state of the

RLF parameters associated with the previous RS.

To this end, the RRC needs to know the RS causing the OOS or IS indication. As one

option, the PHY may send an OOS or IS indication having a RS mark. That is, the PHY may

transmit a SS OOS or IS indication to the RRC, and when the CSI-RS is configured, it may

transmit a CSI-RS OOS or IS indication to the RRC. As another option, without a RS mark, the

RRC may recognize the OOS or IS indication, which is received from the PHY after the time

when the RS having priority is configured according to a preset prioritization rule, as being

associated with the RS with priority.

aggregate indication to the higher layer (RRC) according to an embodiment of the disclosure.

Referring to FIG. 12, the physical layer may provide a per-RS indication or an aggregate

indication to the higher layer (RRC). When the per-RS indication is used, the PHY performs

RLM for all RSs regardless of priority and sends each indication with a RS mark to the higher

layer, and the RRC checks the RS mark and applies the RLF parameters associated with the RS

with priority. When the aggregate indication is used, the PHY performs RLM only for the RS

with priority, and the RRC may recognize the indication, which is received after the time when

the RS having priority is configured, and applies the RLF parameters associated with the RS

with priority.

19220702_1 (GHMatters) P112443.AU

If the RRC distinguishes the indication in the above method, the corresponding RLF

parameters can be applied as follows.

- Condition for applying different RLF parameters

In the terminal, there may be a case where the CSI-RS is IS and the associated SS is not

always IS.

FIG. 13 illustrates a case where the CSI-RS is IS for the terminal but the related SS is

not IS according to an embodiment of the disclosure.

Referring to FIG. 13, although most of the wide beam 1305 carrying the SS is blocked

by the building 1320, one narrow beam 1310 of the wide beam may be not blocked by the

building 1320. In such a case, the reception strength of the SS may be quite low, but CSI-RS

beam 1 may not have a problem at all. Hence, it is necessary to examine the channel state

independently for each RS. This case will be solved by resetting the parameters between RSs.

On the other hand, the remaining CSI-RS beams share the same channel state (OOS) as

the SS, and T_IS for SS IS determination will be longer than T_IS for CSI-RS IS determination.

Hence, it is meaningful to make an in-sync determination if the required number of IS

indications is met. Upon determining that the correlation between the received signal strengths

of the SS beam and the CSI-RS beam is high based on the existing beam measurement values,

the network may instruct the terminal to inherit the state of the existing parameters. Upon

determining that the above correlation is not high and the service is not delay sensitive, the

network may instruct the terminal to reset the state of the existing parameters.

- Number of consecutive indications

There is the number of consecutive indications among the RLF parameters for each RS.

19220702_1 (GHMatters) P112443.AU

When the CSI-RS is configured at a specific point in time while performing RLM with respect to

the SS, it can be assumed that a policy for giving priority to the CSI-RS is set at that point in

time.

CSI-RS according to an embodiment of the disclosure.

Referring to FIG. 14, for the scenario indicated by indicia 1410, assume that three

consecutive OOS indications for the SS are needed to start the RLF timer and two consecutive

OOS indications for the CSI-RS are needed to start the RLF timer. Assume that two

consecutive OOS indications for the SS are generated before the CSI-RS is configured. When

the RLM state (cumulative number of existing indications) is inherited, even if only one OOS

indication for the CSI-RS occurs after CSI-RS configuration, the RRC knows that the cumulative

number of OOS indications is three and starts the RLF timer. When the RLM state is reset, the

RRC starts the RLF timer when receiving two consecutive OOS indications for the CSI-RS after

CSI-RS configuration.

For the scenario indicated by indicia 1420 in FIG. 14, the RLF timer may be started after

the CSI-RS is configured, and when the CSI-RS is released while the IS indication is being

generated based on the CSI-RS, RLM may be performed based on the SS again. To stop the

RLF timer, the RLM state (cumulative number of existing indications) may be inherited or be

reset. When inherited, the number of existing IS indications for the CSI-RS is kept, and when

SS indications for the SS occur, the RLF timer is stopped according to the cumulative number of

consecutive IS indications regardless of the RS type. When reset, the number of existing IS

19220702_1 (GHMatters) P112443.AU indications for the CSI-RS is ignored, and the number of consecutive IS indications is counted for the SS to stop the RLF timer.

- Timer value

There is a timer value among the RLF parameters for each RS. When the CSI-RS is

configured at a specific point in time while performing RLM based on the SS, it can be assumed

that a policy for giving priority to the CSI-RS is set at that point in time. In FIG. 15, for the

scenario indicated by indicia 1510, the terminal has started the RLF timer according to the OOS

indications for the SS. Thereafter, when the CSI-RS is configured, the RLM state (timer value)

may be inherited or be reset. When the timer value is inherited, the RLF timer is run until the

CSI-RS generates a given number of IS indications by continuously applying the SS RLF timer

value or until the timer value expires.

In another embodiment, when the CSI-RS is configured, only the timer value is changed

for the CSI-RS and the elapsed timer value can be inherited as it is. When the parameter is to

be reset, the previous timer is reset at the time when the CSI-RS is configured. If the CSI-RS

measurement generates an IS indication, the timer is stopped, and if the CSI-RS measurement

generates a preset number of consecutive OOS indications, the timer is started.

CSI-RS according to an embodiment of the disclosure.

Referring to FIG. 15, for the scenario indicated by indicia 1520, the CSI-RS is

configured, the RLF timer for the CSI-RS is run, the CSI-RS measurement generates IS

indications, and the CSI-RS is released or unconfigured. In this case, the timer for the CSI-RS

19220702_1 (GHMatters) P112443.AU may be reset, and the RLF timer for the SS may be newly applied. Alternatively, the CSI-RS timer value may be inherited, and the SS timer can be run until the SS measurement generates a preset number of consecutive IS indications or until the timer value expires. Or, the elapsed timer value may be inherited, and the remaining timer value can be used for the SS timer.

When the SS timer value is used, SS, if the elapsed time has already passed the SS timer value,

the timer is stopped immediately and a RLF is declared. Otherwise, the SS timer is run until

the remaining timer value expires.

- Signaling RLF parameter application option

For the above two parameters, a static rule may be used, or the network may

dynamically set a rule and notify it to the terminal. In this case, the network may attach a

reset/inherit indication to each of the two parameters and transmit this configuration information

via, e.g., a RRC connection reconfiguration message.

FIG. 16 depicts a case where the base station configures a specific bandwidth part on the

basis of the capabilities and service requirements of the terminal according to an embodiment of

the disclosure.

If one type of RS is configured in the currently active bandwidth part, the terminal 1605

operates according to the RLM/RLF parameters and rules for that RS. If two or more types of

RS are configured in the active bandwidth part, the terminal 1605 determines an RS type having

priority in the bandwidth part according to the priority information between RS types set in

advance or configured by the base station 1610, and operates according to the RLM/RLF

parameters and rules for the determined RS type.

The base station 1610 permits the use of a specific bandwidth part, and, if the SS is

19220702_1 (GHMatters) P112443.AU present in the bandwidth part, it transmits the SS configuration information and corresponding parameters via dedicated signaling (at operation 1621). If the CSI-RS is tobe configured, the base station 1610 transmits the CSI-RS configuration information and corresponding parameters.

If two RSs are to be configured (that is, the SS is transmitted via the bandwidth part and the

CSI-RS transmitted via a narrow band beam is required for data transmission and reception of

the terminal 1605), the base station transmits the corresponding configuration information,

parameters, and a prioritization rule for RLM. In addition, the base station can attach an

inherit/reset indication to the parameter whose value is being counted at the time of RLF

parameter switching.

Referring to FIG. 16, the SS-related configuration information and RLM/RLF parameter

set may be transmitted via a broadcast channel or shared channel through which system

information is transmitted (option 1). Or, the initial SS-related RLM/RLF parameters are given

to the terminal 1605, and the SS-related configuration information and RLM/RLF parameter set

may be transmitted via dedicated signaling using a RRCconnectionReconfiguration message

after RRC connection establishment (option 2).

The terminal 1605 transmits its capability information (beamforming, preferred

bandwidth and frequency) and service information (delay sensitiveness) to the base station 1610

(at operation 1623). Based on the service information, the base station 1610 assigns a

bandwidth part having a numerology matching enhanced mobile broadband (eMBB),

ultra-reliable low latency communications (URLLC), or massive machine type communications

(mMTC) to the terminal 1605 (at operation 1625). In addition, the base station 1610 checks

whether the SS is present in the assigned bandwidth part, and if present, it transmits the

19220702_1 (GHMatters) P112443.AU

SS-related configuration in and corresponding RLM/RLF parameters (at operation 1627).

Thereafter, the terminal 1605 measures the SS in the assigned bandwidth part (at

operation 1629), and feeds the measurement result back to the base station 1610 (at operation

1631). The base station 1610 may configure the CSI-RS (at operation 1633). IfthereisnoSS

in the assigned bandwidth part, the terminal may measure the SS in the cell or bandwidth part

associated with initial RRCConnection and send the measurement information to the base station.

Alternatively, the base station can configure the CSI-RS without referring to SS measurement

feedback. This CSI-RS will be used in the assigned bandwidth part.

When the CSI-RS is configured, the base station 1610 notifies the terminal 1605 of the

corresponding configuration information and parameters, and notifies the RS prioritization index

(at operation 1635). Upon determining that the correlation between the received signal

strengths of the CSI-RS beam and the SS beam is strong on the basis of the service information

received from the terminal 1605 and the beam feedback received from other terminals, the base

station 1610 transmits the terminal 1605 an inherit indication for applying the RLF parameters.

Otherwise, the base station 1610 transmits the terminal 1605 a reset indication for applying the

RLF parameters.

Upon receiving the above information, the terminal 1605 communicates via the assigned

bandwidth part, and performs RLM according to the given prioritization rule (at operation 1637).

If there is no SS in the corresponding bandwidth part, RLM/RLF can be performed using

only CSI-RS configuration information and parameter information. As another option, the

information (frequency, cell ID, or bandwidth part ID) on the bandwidth part in which the SS is

present, measurement gap information for measuring the SS, SS configuration information of the

19220702_1 (GHMatters) P112443.AU bandwidth part, RLF parameter information, prioritization rule information, and reset indication information can be sent to the terminal 1605, and the terminal 1605 can measure both the SS and the CSI-RS while observing the two bandwidth parts in a time division manner and perform RLF operations according to the prioritization rule and the reset indication. If the bandwidth part where the SS is present and the bandwidth part where only the CSI-RS is present are physically separated rather than quasi co-located or co-located sites, the correlation between the received signal strengths of the SS and the CSI-RS maybe weak. In this case, the base station 1610 may provide a reset indication for applying the RLF parameters.

FIG. 17 depicts a case where UE beamforming related capability information, requested

service related information, and preferred bandwidth part information are transmitted via a

separate RRC messages after connection setup according to an embodiment of the disclosure.

Referring to FIG. 17, the terminal 1705 may transmit the beamforming capability

information, required service related information, and preferred bandwidth part information to

the base station 1710 after connection setup via a separate RRC message (at operation 1729), not

via a RRCConnectionSetup message. Upon receiving the above information before configuring

the CSI-RS, the base station 1710 transmits the prioritization rule and the RLF parameter

inherit/reset indication to the terminal 1705 based on the received information (at operation

1733).

If the beamforming capability information, required service related information, and

preferred bandwidth part information are received after configuring the CSI-RS, the base station

1710 transmits the prioritization rule and the RLF parameter inherit/reset indication that are set

to the preset default values.

19220702_1 (GHMatters) P112443.AU

As another option, the terminal 1705 may have present default values for the

prioritization rule and the RLF parameter inherit/reset indication. If the base station 1710 does

not provide specific values, the terminal 1705 may apply the preset default values.

For operations 1721 to 1735, refer to the corresponding operations in FIG. 16.

As another embodiment, if an RLF is declared owing to the RLM operation performed

for each active bandwidth part (BWP) or other causes, the terminal switches itself to a preset

BWP and attempts to access the preset BWP. If the connection is successful, the terminal does

not declare an RLF. If the connection is unsuccessful, the terminal can declare an RLF and

search for a new cell. Here, the preset BWP can be a default BWP or another configured BWP.

Access to the preset BWP may be made through the RACH or through the physical uplink

control channel (PUCCH) using a dedicated preamble such as a reconnection indication or a

scheduling request.

In particular, when the terminal performs switching on a BWP basis, the following

embodiments may be added with respect to the RLM/RLF operation.

(1) The network may configure a radio link monitoring reference signal (RLM-RS) to

the terminal. The RLM-RS may be a SS (synchronization signal), CRS (cell specific reference

signal), SRS (sounding reference signal), or CSI-RS (channel state information reference signal),

or a combination thereof. When a RLM-RS is configured to the terminal, the base station may

transmit RS information on the time-frequency resource location and code (if code is used).

When a specific pattern is agreed between the terminal and the network, the pattern information

can be transmitted. Upon receiving this configuration information, the terminal refers to the

time-frequency resource of the RLM-RS and applies the RLM parameters associated with the RS,

19220702_1 (GHMatters) P112443.AU where the physical layer may transmit an IS (in-sync) indication or an OOS (out-of-sync) indication to the higher layer.

The RLM parameters may include an IS threshold (RSRP, RSRQ, RSSI, or BLER in

consideration of hypothetical PDCCH transmission) to generate an IS indication if the reception

power is higher than the IS threshold, the number of RSs or beams that should be higher than the

IS threshold, an OOS threshold to generate an OOS indication if the reception power is lower

than the OOS threshold, the number of RSs or beams that should be lower than the OOS

threshold, the time window for IS and OOS measurement, and the interval between IS or OOS

indications. This parameter information can be notified through dedicated signaling when the

RS such as SS or CSI-RS is configured, or can be notified via broadcast signaling using system

information.

(2) When the network configures the RLM-RS to the terminal, this RS may be present or

may be not present in all the assigned bandwidth parts (BWP). In particular, when the terminal

uses a scheduled BWP (active BWP), if there is no RLM-RS in the BWP, the terminal may

temporally switch to the BWP including a frequency location where the RLM-RS exists and

receive and measure the RLM-RS to generate a periodic indication.

[Fallback to RLM-RS BWP or gap for active BWP] In the above description, switching

from the originally scheduled active BWP to a BWP having a RLM-RS is referred to as fallback.

The network can provide the terminal with information such as fallback time, stay time at the

fallback BWP, return time to switch back to the originally scheduled active BWP, and repetition

period of a fallback pattern. When the network schedules a configured BWP not including a

RLM-RS for the terminal based on the time information of the RLM-RS, the network can

19220702_1 (GHMatters) P112443.AU configure a measurement gap for RLM, during which the terminal does not have to monitor the scheduled active BWP. This measurement gap can be specified by information such as the start point of the gap, the duration of the gap, and the repetition period.

When a measurement gap for RLM is configured for the terminal, the terminal monitors

the currently scheduled active BWP, switches to the BWP where the RLM-RS is configured at

the start time of the gap, receives the RLM-RS for the duration of the gap, and switches back to

the original active BWP to perform communication.

according to an embodiment of the disclosure.

Referring to FIG. 18, if only one RLM-RS exists, the base station can provide the

terminal with an RLM-RS configuration independent of the active BWP currently monitored by

the terminal (i.e., absolute RLM-RS information). When scheduling an active BWP for the

terminal, the base station determines whether the active BWP has an RLM-RS (at operation

1905). If the active BWP has an RLM-RS, the base station may skip transmitting the fallback

information or the RLM-RS measurement gap information for a separate RLM-RS BWP (at

operation1910). In this case, the terminal performs RLM without switching to another BWP

(at operation 1915).

If the scheduled active BWP has no RLM-RS (at operation 1920), the base station

transmits the fallback information and the RLM-RS measurement gap information for the

RLM-RS BWP (at operation 1925). Upon receiving this information, the terminal can monitor

the active BWP, switch to the RLM-RS fallback BWP or receive and measure the RLM-RS

based on the gap information, and return to the original active BWP (at operation 1930).

19220702_1 (GHMatters) P112443.AU

FIG. 19 depicts RLM-RS signaling when the active BWP has a RLM-RS and when the

active BWP does not have a RLM-RS according to an embodiment of the disclosure.

according to an embodiment of the disclosure.

If there are multiple RLM-RSs referring to FIG. 20, different types of RLM-RSs may be

used for the active BWPs, and different types of RLM BWPs may be used accordingly.

For example, the RLM-RS close to the active BWP in the frequency domain can be

selected and used. In the case of option 2 of FIG. 19, instead of the initially configured

RLM-RS, a new RLM-RS can be configured based on the active BWP. In addition, a RLM

fallback BWP may be configured based on the newly configured RLM-RS. When an active

BWP is configured, the base station can selectively notify this information to the terminal.

For example, if the active BWP is BWP3, the RLM-RS at this time may be the RLM-RS

present in BWP4 and the RLM fallback BWP may be BWP4. This configuration may be set as

a new configuration where the active BWP is BWP1, the fallback BWP is BWPO, and the

RLM-RS is the RLM-RS present in BWPO. In FIG. 19, this is represented as "RLM-RS

configuration" and "RLM fallback BWP based on scheduled BWP". The RLM-RS

configuration (second signaling in FIG. 19) may refer to all information about the RLM-RS

existing in the corresponding cell. The RLM-RS configuration after the active BWP is

determined is limited to the information about the RLM-RS to be used when the active BWP is

used. The latter information takes precedence over the former information.

(3) As indicated in subsection (2), the RLM-RS may be present in all BWPs. In this

case, instead of switching to a specific BWP to measure the RLM-RS, the terminal measures the

19220702_1 (GHMatters) P112443.AU

RLM-RS present in each scheduled active BWP and applies the corresponding RLM parameters

to generate an OO/IS indication.

In the first diagram of FIG. 19 where all RLM-RS information is given, since the base

station knows that the RLM-RS is present in all BWPs, it does not provide RLM-RS information

specific to the active BWP. The terminal compares the location information of the RLM-RS

with the frequency information of the active BWP, recognizes that the RLM-RS is present in the

active BWP, and performs RLM operation in the active BWP without performing fallback or

measurement gap operations.

(4) If there is an RLM fallback BWP or RLM measurement gap configuration, the

terminal measures the RLM-RS at the indicated time to generate an indication and operates the

RLF timer by applying the layer 3 parameters based on the indication. However, when an

active BWP is scheduled (or switched) and an indication is received owing to the RLM-RS

present in each active BWP as described in subsection (3), there is a choice of whether to inherit

or reset the current state when applying the L3 parameters.

If the channel correlation between BWPs is not large, the reset option can be applied;

and if the channel correlation is large, the inherit option can be applied. For the number of

consecutive IS or OOS indications used to start or stop the RLF timer among theL3 parameters,

the terminal inherits the RLF parameter state of the previous active BWP (the number of

consecutive IS indications generated in the previous active BWP and the number of consecutive

OOS indications generated in the previous active BWP) and uses the same in the switched active

BWP.

When the RLF timer has been started in the previous active BWP, if a preset number of

19220702_1 (GHMatters) P112443.AU consecutive IS indications (including inherited ones) are generated from the switched active

BWP, the terminal stops the timer. If a preset number of consecutive OOS indications

(including inherited ones) are generated from the switched active BWP, the terminal keeps the

timer running.

If the channel correlation between BWPs is not large, the reset option can be applied.

In this case, at the time when the active BWP is switched (or scheduled) to another BWP, the

terminal resets the number of consecutive IS indications generated in the previous active BWP to

zero and resets the number of consecutive OOS indications generated in the previous active

BWP to zero. If the RLF timer has been started in the previous active BWP, the terminal resets

the timer value to the initial value and stops the timer. Thereafter, if a preset number of

consecutive IS or OOS indications are generated from the switched active BWP, the terminal

operates the timer accordingly.

(5) Since the various RSs can be used as the RLM-RS as described in subsection (1),

different RLF parameter sets may be set for different BWPs. When a new active BWP is

scheduled, the base station may transmit the terminal at least some of the following values as

RLF parameters: the IS threshold (RSRP, RSRQ, RSSI, SINR, or BLER in consideration of

hypothetical PDCCH transmission) to generate an IS indication if the reception power is higher

than the IS threshold, the OOS threshold (RSRP, RSRQ, RSSI, SINR, or BLER in consideration

of hypothetical PDCCH transmission) to generate an OOS indication if the reception power is

lower than the OOS threshold, the time window for IS and OOS measurement, the interval

between IS or OOS indications sent to the higher layer, the number of RSs or beams that should

be higher than the IS threshold for IS indication generation, the number of RSs or beams that

19220702_1 (GHMatters) P112443.AU should be lower than the OOS threshold for OOS indication generation, the RLF timer value, the number of consecutive OOS indications to start the RLF timer, and the number of consecutive IS indications to stop the running RLF timer.

FIG. 21 is a block diagram of a base station according to an embodiment of the

disclosure.

Referring to FIG. 21, the base station may include a transceiver 2110, a controller 2120

(e.g., at least one processor), and a storage 2130 (e.g., memory).

In the disclosure, the controller 2120 may be a circuit, an application specific integrated

circuit, or at least one processor.

The transceiver 2110 can transmit and receive signals to and from other network entities.

For example, the transceiver 2110 can transmit system information, synchronization signals, or

reference signals to a terminal.

The controller 2120 can control the overall operation of the base station according to the

embodiments of the disclosure. For example, the controller 2120 may control the signal flow

between blocks to perform the operations described in the above sequence diagrams.

Specifically, the controller 2120 may control the proposed operations to report a radio

link problem to the higher layer according to the embodiments of the disclosure.

The storage 2130 may store at least one of information transmitted or received through

the transceiver 2110 and information generated by the controller 2120.

For example, the storage 2130 may store information related to an event that is defined

to report a radio link problem.

FIG. 22 is a block diagram of a terminal according to an embodiment of the disclosure.

19220702_1 (GHMatters) P112443.AU

Referring to FIG. 22, the terminal may include a transceiver 2210, a controller 2220 (e.g.,

at least one processor), and a storage 2230 (e.g., memory).

In the disclosure, the controller 2220 may be a circuit, an application specific integrated

circuit, or at least one processor.

The transceiver 2210 can transmit and receive signals to and from other network entities.

For example, the transceiver 2210 can receive system information, synchronization signals, or

reference signals from the base station.

The controller 2220 can control the overall operation of the terminal according to the

embodiments of the disclosure. For example, the controller 2220 may control the signal flow

Specifically, the controller 2220 can control the operation of measuring the SS, the BRS,

or the like in connection to the radio link according to the embodiments of the disclosure.

The storage 2230 may store at least one of information transmitted or received through

the transceiver 2210 and information generated by the controller 2220.

For example, the storage 2230 may store information needed for radio link monitoring

according to an embodiment of the disclosure.

As described above, the RLM/RLF parameters can be configured differently according

to the types of RS. The RLM/RLF parameters can also be configured differently according to

the types of service.

type of a service received by the terminal according to an embodiment of the disclosure. When

the base station 2310 knows the service desired by the terminal 2305, it configures the RLM-RS

19220702_1 (GHMatters) P112443.AU suitable for the service and configures the RLM/RLF parameters associated with the RLM-RS.

Upon receiving the configuration information, the terminal 2305 may perform RLM based on

this information and operate the timer according to IS/OOS indications using the RLF

parameters to declare anRLF. Here, the RLM parameters sent by the base station 2310 may

include the RLM-RS configuration information (RS type, RS time-frequency location, threshold

to be compared with a measurement value for each RS), and RLF parameters (RLF timer value,

the number of consecutive IS indications, the number of consecutive OOS indications). Upon

receiving this information, the terminal 2305 may identify the location of the corresponding RS

and transmit a periodic IS or OOS indication to the RRC based on the given RLM parameters.

The RRC layer can stop or start the RLF timer when it receives a preset number of consecutive

IS or OOS indications.

The base station may identify the service type of the terminal in various ways. When a

bearer is set for the terminal, the IP address and port of the corresponding server can be known

from the five tuple of IP packets of the E-UTRAN radio access bearer (E-RAB) or flow, and the

type of traffic can be identified from the quality of service (QoS) flow information. The base

station may know the service type for each bearer from the identified traffic type. If the

terminal has multiple bearers for different types of services, the base station can configure the

RLM/RLF configuration based on a service with stricter constraints. For example, when a

voice over internet protocol (VoIP) service and an ordinary eMBB data service coexist in the

terminal, the base station can provide the RLM/RLF configuration based on the failure-sensitive

VoIP service due to the characteristics of voice traffic.

The following embodiment can be considered as a structure that can be contained in

19220702_1 (GHMatters) P112443.AU

ASN.1oftheRRC. Since the Pcell or Pscell performs the RLM/RLF operation, the following

IE can be carried by the container for the Pcell/Pscell configuration in an RRC message. The

following IEs may also be carried by the measConfig IE with the RS configuration for mobility.

PCellConfig or measConfig >

RLM-config

- List of RLM-RS

* List of RLM-resource-config-SS ex. {SSB1,SSB2,SSB5}

* List of RLM-resource-config-CSIRS ex. {1-2 (for 2 level) or 1-1-3 (for 3 level)

etc.}

- Threshold info

0 PairofBLERID ex. {0 or 1}

List of RLM-resource-config-SS may include a list of SSB indexes used for the

RLM-RS, time-frequency location information, or repeated pattern information. List of

RLM-resource-config-CSIRS may include a list of pointers to the CSIRS resources

corresponding to some or all of the CSI-RSs currently configured in the Pcell or Pscell, or a list

of resources of a newly added CSI-RS (time-frequency location information, repeated pattern

information). PairofBLERID indicates the ID of a pair of hypothetical PDCCH BLER

values used for IS and OOS determination among preset pairs of target hypothetical PDCCH

BLER values of the received signal for each RS. This indication may indicate both the BLER

to be used and the service mapped with the BLER. For example, "0" may indicate the pair of

BLER values used in LTE and indicate a general service. "1" may indicate aneMBB orVoIP

service and a pair of preset BLER values associated the service. This service-specific threshold

19220702_1 (GHMatters) P112443.AU

(or BLER value) information can be provided by the base station to the terminal via dedicated

signaling. The threshold information may be specified for each service (not for each terminal)

in the specification. An RRC message or MAC CE may be used to deliver the threshold

information specified for each terminal. In another embodiment, if the BLER value is not set, a

preset default BLER value may be applied. For example, when the default BLER is a LTE

BLER, if the terminal in connected state receives an RS configuration through RLM-config but

does not receive a Pair-ofBLERID configuration, it may apply the LTE BLER by default.

Later, if a PairofBLERID configuration is provided, it may override the default BLER.

Here, the terminal may regard the service type associated with the default BLER as the default

service type.

For RLF parameter signaling related to the service type, it is possible to configure the

RLF parameters for each service type identified by the system, such as the number of

consecutive IS or OOS indications for timer operation, timer value, RS measurement time

window (or interval) for OOS determination, and RS measurement time window (or interval) for

IS determination. These parameters can be delivered via RLF-TimersandConstants signaling of

the CellGroup configuration container among the RRC messages, and the parameters can be

configured and transmitted for each service. Among the parameter values configured for each

service, the terminal can select and use the RLF parameter corresponding to the service type

mapped with the BLER value selected according to a value indicated by Pair ofBLERID of

RLM-config.

For example, the RLF parameters corresponding to normal service and VoIP can be

delivered at one time in advance as follows.

19220702_1 (GHMatters) P112443.AU

RLF-TimersAndConstants C:=IC { release NULL, setup CHOICE For normalserviceparam SEQUENCE{ t310 ENRATED { msO, ma50, =100, m9200, ma500, as1000, ms2000}, n310 ENU:RATED

( ni, n2, n3, n, n6, n8, n10, n20), t311 ENUMERATED

( malOOO, ms3000, =s5000, msO0000, =s15000, ms20000, ms30000), n311 ENUMERATED { ni, n2, n3, n4, n5, nS, n8, n10},

ForVoIP SEQUENCE t310 ENUN!RATED { msO, mas5O, malO), n310 ENNIERATED

( ni, n2, n3, n), t311 ENUMERATED { m91000, m3000, s5000, m910000, =15000}, n311 ENUMERATED

( ni, n2, n3, n4),

The base station can transmit the RLM configuration information when the terminal

transitions from idle state to connected state or when the terminal makes the initial RRC

connection. In the case of handover to another cell as shown in FIG. 24, the target cell 2415

receives the service information of the corresponding terminal from the serving cell 2410, and

transmits the RLM-RS configuration, the BLER setting information, and the RLF parameters to

the serving cell 2410 based on the received service information. The serving cell 2410 may

forward this information via an RRC message. In addition, when the serving cell recognizes

that the service type of the terminal 2405 in connected state has changed as described above, the

serving cell 2410 may transmit new BLER information via a RRC reconfiguration message or

transmit both new BLER information and information on the newly configured RLM-RS.

Upon receiving the above configuration information, the terminal checks the RLM-RS

configuration information, and measures the received signal strength (RSRQ, RSRP, or SINR) of

each RS for a specific time period to generate a preset number of samples, and converts the

sample values into a representative value. For a preset number of RSs or more, if the

19220702_1 (GHMatters) P112443.AU corresponding representative value exceeds the BLER threshold, the terminal sends an IS indication to the RRC, and otherwise it sends an OOS indication to the RRC. When a number of consecutive IS or OOS indications indicated by the RLF parameters are received from the physical layer, the RRC starts or stops the RLF timer indicated by the RLF parameters.

In another embodiment, the base station may transmit a command message indicating a

subset of pre-configured RSs to instruct the terminal to monitor only the RLM-RS included in

the subset. Here, the command message may be an RRC message, a MAC-CE message, or a

downlink control information (DCI) message. The command message may also include an

absolute or relative indicator to the pre-configured RS.

The command message may instruct the terminal to perform radio link monitoring using

the RLM-RS indicated by the command message. In this case, although the terminal may

measure and monitor both the indicated RLM-RS and other RSs, the terminal may perform radio

link monitoring (e.g., generating an out-of-sync indication or an in-sync indication and sending it

to the higher layer) by using only the RLM-RS indicated by the command message.

In another embodiment, instead of monitoring all RSs pre-configured as the RLM-RS,

the base station may transmit a command message to instruct the terminal to monitor, when a

specific BWP is configured for the terminal, only the RS corresponding to the frequency range

of the configured BWP or the RSs dedicated to the configured BWP among the RSs set as the

RLM-RS. Here, the command message may be an RRC message, a MAC-CE message, or a

DCI message. The command message may also include an absolute or relative indicator to the

pre-configured RS.

19220702_1 (GHMatters) P112443.AU the RLM-RS indicated by the command message. In this case, although the terminal may measure and monitor both the indicated RLM-RS and other RSs, the terminal may perform radio link monitoring (e.g., generating an out-of-sync indication or an in-sync indication and sending it to the higher layer) by using only the RLM-RS indicated by the command message.

The command message may instruct the terminal to, when the terminal switches the

BWP, find and monitor the RLM-RS suitable for the switched BWP so as to generate an

out-of-sync indication or an in-sync indication and send it to the higher layer by using the

suitable RLM-RS.

In another embodiment, the base station may transmit a command message containing a

numeric value to instruct the terminal to perform RLM. Here, the command message may be

an RRC message, a MAC-CE message, or a DCI message. Upon receiving the command

message, the terminal may measure the available RLM-RSs, list the measurement values and RS

IDs in order of performance, and perform radio link monitoring (e.g., generating an out-of-sync

indication or an in-sync indication and sending it to the higher layer) by using the same number

of RSs as the received value.

In the above embodiments, when signaling the RLF timer and constants for each

threshold corresponding to a particular service, the base station may configure the timer and

constants for each service threshold and send them to the terminal via ue-TimersAndConstants

IE or rlf-TimersAndConstants IE. Thereafter, when the base station detects a change in the

service type and transmits only an indication to a changed BLER threshold pair for IS/OOS

determination, it may not transmit the RLF timer and constant values together with the threshold

pair indication signaling. In this case, signaling overhead can be reduced since the base station

19220702_1 (GHMatters) P112443.AU does not have to transmit again all the changed values of the other RLF parameters according to the service type change. The timer and constants configuration per threshold described above can be applied to all timers that are affected by the service change. For example, this is applicable to T301, T310, T313, T311, N310, N311, N313, and N314.

In the above embodiments, instead of monitoring all RSs configured as the RLM-RS, the

base station may transmit a command message to instruct the terminal to monitor, when a

RLM-RS. This signaling is described in more detail. When the base station configures the

RLM-RS for the terminal, it can indicate an association between the RS and a bandwidth part

(BWP). Based on the RS-BWP association the terminal can use only the RLM-RS associated

with the currently active BWP for the RLM operation. ASN.1 level signaling for this is as

follows. The RLM-RS list created by the base station is a set of RLM-RSs, and each RLM-RS

can indicate the RS type (SSB or CSI-RS).

Each RLM-RS may include an index of the BWP where the RLM-RS is to be activated.

If the SSB is used for RLM, the RS can be specified by the index of the SSB operated by the

serving cell. If the CSI-RS is used for RLM, some of the CSI-RSs configured for beam

management of the SpCell can be used as the CSI-RS for RLM. To refer to this, the predefined

CSI-RS resource ID may be used to designate the CSI-RS for RLM. The CSI-RS designation

can be transmitted together with the time-frequency location information and repeated

information of the corresponding CSI-RS. In addition, the base station may transmit thresholds

serving as a criterion for determining the level of the reception strength of the RSs for IS or OOS

19220702_1 (GHMatters) P112443.AU indications. In this case, a threshold pair index associated with preset thresholds can be delivered instead of the thresholds themselves. Based on the threshold pair index, the terminal may select one of the threshold pairs predefined in the standard and apply the selected threshold pair to RLM.

These parameters can be delivered via a RRC message, MAC CE, or DCI. The

following shows a case where the parameters are included in SpCell configuration of a RRC

message.

SpCellConfig:: = SEQUENCE{

-- Parameters for the synchronous reconfiguration to the target SpCell:

reconfigurationWithSync SEQUENCE{

spCellConfigCommon ServingCellConfigCommon,

newUE-Identity RNTI-Value,

t304 ENUMERATED {ms50, ms1O0, ms150,

ms200, ms500, ms1000, ms2000, msI0000-v1310},

rach-ConfigDedicated RACH-ConfigDedicated

OPTIONAL -- Need M

} OPTIONAL,

-- Cond SpCellChange

rlm-config RLM-RSConfig

OPTIONAL, -- Need M

19220702_1 (GHMatters) P112443.AU spCellConfigDedicated ServingCellConfigDedicated

OPTIONAL -- Need M

}

SCellToReleaseList:= SEQUENCE (SIZE (1..maxNrofSCells)) OF

SCellIndex

SCellToAddModList::= SEQUENCE (SIZE (1..maxNrofSCells)) OF

SCellConfig

SCellConfig:: = SEQUENCE{

sCellIndex SCellIndex,

sCellConfigCommon ServingCellConfigCommon

OPTIONAL, -- Cond SCellAdd

sCellConfigDedicated ServingCellConfigDedicated OPTIONAL-- Cond

SCellAddMod

}

RLM-RSConfig::= SEQUENCE{

rlmInSyncOutOfSyncThrehold INTEGER (0..1)

OPTIONAL, -- Need M

rlmRSList SEQUENCE (SIZE (1..8)) OF RLM-RS

}

RLM-RS::= CHOICE{

RLM-SSB INTEGER (0..63)

19220702_1 (GHMatters) P112443.AU

RLM-CSIRS INTEGER

(O..NZP-CSI-RS-ResourceMax - 1)

}

RLM-RS is an IE that sets properties of individual RLM-RSs included in rlmRSList.

Each RLM-RS may be either an SSB or a CSI-RS. The SSB can be specified using the SSB

index used in the corresponding cell. The CSI-RS can be specified using the CSI-RS resource

index set for beam management or RRM in the corresponding cell. In this case, each SSB or

CSI-RS may further include information on which RSs are assigned to which BWPs. For

example, the base station may include the bandwidth part ID for which the SSB or CSI-RS is

used and the RS index in this signaling IE. In case of CSI-RS, time related information of the

RS may be further included. For example, periodicity information and a slot offset indicating

the position of the reference subframe at which a repetition pattern starts may be further

included.

The network can assign a maximum number of RLM-RSs and a minimum number of

RLM-RSs to each configured BWP, and the terminal can monitor only the RLM-RS assigned to

the currently active BWP. Here, the maximum and minimum number of RLM-RSs may be

specified by the standard specification or the base station. The base station may identify the

number of RSs that can be simultaneously monitored by the terminal based on the capability

information received from the terminal. Currently, to perform the RLM operation of the active

BWP, the minimum number of RLM-RSs may be one or more.

19220702_1 (GHMatters) P112443.AU

While the disclosure has been shown and described with reference to various

embodiments thereof, it will be understood by those skilled in the art that various changes in

form and details may be made therein without departing from the spirit and scope of the

disclosure as defined by the appended claims and their equivalents.

In the claims which follow and in the preceding description of the invention, except

where the context requires otherwise due to express language or necessary implication, the word

"comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e.

to specify the presence of the stated features but not to preclude the presence or addition of

further features in various embodiments of the invention. It is to be understood that, if any

prior art publication is referred to herein, such reference does not constitute an admission that the

publication forms a part of the common general knowledge in the art, in Australia or any other

country.

19220702_1 (GHMatters) P112443.AU

Claims

1. A method performed by a terminal in a wireless communication system, the

method comprising:

reference signals for a radio link monitoring (RLM);

for each active bandwidth part (BWP) of a cell;

monitoring a radio link quality of the reference signal in an active BWP of the cell,

wherein the radio link quality relates to a reception strength of the reference signal;

comparing the radio link quality of the reference signal with a first threshold for an

in-sync or a second threshold for an out-of-sync, wherein the first threshold and the second

threshold are identified based on the threshold information for the RLM, wherein the threshold

information includes a block error rate (BLER) threshold pair index corresponding to the first

threshold for the in-sync and the second threshold for the out-of-sync;

indicating the in-sync to a higher layer of the terminal, in case that the radio link quality

of the reference signal is greater than the first threshold during afirst predetermined duration

based on the configuration information of the reference signal for the RLM; and

indicating the out-of-sync to the higher layer of the terminal in case that all radio link

quality of the reference signal is lower than the second threshold during a second predetermined

duration based on the configuration information of the reference signal for the RLM,

2. The method of claim 1,

wherein the configuration information of the reference signal for the RLM includes at

least one of: a synchronization signal block (SSB) index; a channel state information - reference

signal (CSI-RS) index.

3. The method of claim 1,

wherein the cell corresponds to a PCell,

wherein the BLER threshold pair index is 0 or 1, and

wherein the BLER threshold pair index indicates the ID of a pair of hypothetical BLER

values used for out-of-sync and in-sync indication.

4. The method of claim 1,

wherein the configuration information of the reference signal for the RLM includes a

number of beams needed for a determination of the out-of-sync and the in-sync.

5. A method performed by a base station in a wireless communication system, the

method comprising:

signals for a radio link monitoring (RLM);

19220702_1 (GHMatters) P112443.AU transmitting, to the terminal, a radio resource control (RRC) message for a primary cell

threshold information for the RLM, wherein the reference signal for the RLM is configured for

each active bandwidth part (BWP) of a cell; and

transmitting the reference signal including at least one of: a synchronization signal block

(SSB); a channel state information - reference signal (CSI-RS),

the in-sync and the second threshold for the out-of-sync,

terminal, and

wherein the number of reference signals for the RLM that can be simultaneously

monitored by the terminal are indicated by the capability information.

6. The method of claim 5,

19220702_1 (GHMatters) P112443.AU least one of: an SSB index; a CSI-RS index.

7. The method of claim 5,

wherein the cell corresponds to a PCell,

wherein the BLER threshold pair index is 0 or 1, and

values used for out-of-sync and in-sync indication.

8. The method of claim 5,

number of beams needed for a determination of the out-of-sync and the in-sync.

9. A terminal in a wireless communication system, the terminal comprising:

a transceiver; and

at least one processor configured to control the terminal to:

transmit, to a base station via the transceiver, capability information for

identifying a number of reference signals for a radio link monitoring (RLM),

receive, from the base station via the transceiver, a radio resource control (RRC)

message for a primary cell (PCell) configuration including configuration information of a

reference signal for the RLM and threshold information for the RLM, wherein the reference

signal for the RLM is configured for each active bandwidth part (BWP) of a cell,

monitor a radio link quality of the reference signal in an active BWP of the cell,

19220702_1 (GHMatters) P112443.AU wherein the radio link quality relates to a reception strength of the reference signal, compare the radio link quality of the reference signal with a first threshold for an in-sync or a second threshold for an out-of-sync, wherein the first threshold and the second threshold are identified based on the threshold information for the RLM, wherein the threshold information includes a block error rate (BLER) threshold pair index corresponding to the first threshold for the in-sync and the second threshold for the out-of-sync, indicate the in-sync to a higher layer of the terminal, in case that the radio link quality of the reference signal is greater than the first threshold during afirst predetermined duration based on the configuration information of the reference signal for the RLM, and indicate the out-of-sync to the higher layer of the terminal in case that all radio link quality of the reference signal is lower than the second threshold during a second predetermined duration based on the configuration information of the reference signal for the

RLM,

wherein the number of reference signals for the RLM that can be simultaneously

monitored by the terminal are indicated by the capability information.

10. The terminal of claim 9,

signal (CSI-RS) index.

11. The terminal of claim 9,

19220702_1 (GHMatters) P112443.AU wherein the cell corresponds to a PCell, wherein the BLER threshold pair index is 0 or 1, and wherein the BLER threshold pair index indicates the ID of a pair of hypothetical BLER values used for out-of-sync and in-sync indication.

12. The terminal of claim 9,

number of beams needed for a determination of the out-of-sync and the in-sync.

13. A base station in a wireless communication system, the base station comprising:

a transceiver; and

at least one processor configured to control the base station to:

receive, from a terminal via the transceiver, capability information for identifying

a number of reference signals for a radio link monitoring (RLM),

transmit, to the terminal via the transceiver, a radio resource control (RRC)

signal for the RLM is configured for each active bandwidth part (BWP) of a cell, and

transmit the reference signal including at least one of: a synchronization signal

block (SSB); a channel state information - reference signal (CSI-RS),

19220702_1 (GHMatters) P112443.AU includes a block error rate (BLER) threshold pair index corresponding to the first threshold for the in-sync and the second threshold for the out-of-sync, wherein, in case that a radio link quality of the reference signal is greater than the first threshold during a first predetermined duration based on the configuration information of the reference signal for the RLM, the in-sync is indicated to the higher layer of the terminal, wherein, in case that all radio link quality of the reference signal are lower than the second threshold during a second predetermined duration based on the configuration information of the reference signal for the RLM, the out-of-sync is indicated to the higher layer of the terminal, and wherein the number of reference signals for the RLM that can be simultaneously monitored by the terminal are indicated by the capability information.

14. The base station of claim 13,

least one of: an SSB index; a CSI-RS index.

15. The base station of claim 13,

wherein the cell corresponds to a PCell,

wherein the BLER threshold pair index is 0 or 1, and

values used for out-of-sync and in-sync indication.

19220702_1 (GHMatters) P112443.AU

16. The base station of claim 13,

number of beams needed for a determination of the out-of-sync and the in-sync.

19220702_1 (GHMatters) P112443.AU