U.S. patent application number 16/447961 was filed with the patent office on 2019-12-26 for method for nr radio link monitoring (rlm) and evaluation period determination.
The applicant listed for this patent is MEDIATEK INC.. Invention is credited to Hsuan-Li Lin, Kuhn-Chang Lin.
Application Number | 20190393980 16/447961 |
Document ID | / |
Family ID | 68980865 |
Filed Date | 2019-12-26 |
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United States Patent
Application |
20190393980 |
Kind Code |
A1 |
Lin; Hsuan-Li ; et
al. |
December 26, 2019 |
Method for NR Radio Link Monitoring (RLM) and Evaluation Period
Determination
Abstract
Methods are proposed to define UE behavior for performing
synchronization signal block (SSB) based radio link monitoring
(RLM) and channel state information reference signal (CSI-RS) based
RLM. In a first novel aspect, if CSI-RS based RLM-RS is not QCLed
to any CORESET, then UE determines that CSI-RS RLM configuration is
error and does not perform RLM accordingly. In a second novel
aspect, SSB for RLM and RLM CSI-RS resources are configured with
different numerologies. UE perform SSB based RLM and CSI-RS based
RLM based on whether the SSB and CSI-RS resources are TDMed
configured by the network. In a third novel aspect, when multiple
SMTC configurations are configured to UE, UE determines an SMTC
period and whether SMTC and RLM-RS are overlapped for the purpose
of RLM evaluation period determination.
Inventors: |
Lin; Hsuan-Li; (Hsin-Chu,
TW) ; Lin; Kuhn-Chang; (Hsin-Chu, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MEDIATEK INC. |
Hsin-Chu |
|
TW |
|
|
Family ID: |
68980865 |
Appl. No.: |
16/447961 |
Filed: |
June 21, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62688450 |
Jun 22, 2018 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C02F 2209/225 20130101;
A01K 63/065 20130101; A01G 2031/006 20130101; A01M 31/002 20130101;
C02F 2209/02 20130101; A01K 63/042 20130101; A01K 63/047 20130101;
A01K 63/045 20130101; H04B 7/01 20130101; H04W 56/005 20130101;
C02F 2103/20 20130101; H04L 5/005 20130101; C02F 2209/42 20130101;
C02F 2209/245 20130101; H04L 1/0026 20130101; A01G 31/02 20130101;
C02F 2101/16 20130101; H04L 5/22 20130101; H04L 27/261 20130101;
C02F 2201/009 20130101; C02F 3/006 20130101; H04L 5/0091 20130101;
H04L 5/0094 20130101; H04L 27/2607 20130101; H04W 56/001 20130101;
H04L 5/0007 20130101; C02F 3/327 20130101; H04W 24/10 20130101;
C12P 5/023 20130101; C02F 2209/06 20130101; H02S 10/10 20141201;
H04W 24/08 20130101; A01G 33/00 20130101 |
International
Class: |
H04L 1/00 20060101
H04L001/00; H04L 5/00 20060101 H04L005/00; H04W 24/10 20060101
H04W024/10; H04W 24/08 20060101 H04W024/08; H04W 56/00 20060101
H04W056/00; H04B 7/01 20060101 H04B007/01; H04L 27/26 20060101
H04L027/26 |
Claims
1. A method comprising: receiving core resource set (CORESET)
configuration by a user equipment (UE) in a new radio (NR) network,
wherein the CORESET configuration comprises one or more CORESETs
for the UE; receiving radio link monitoring (RLM) configuration
comprising resource information of a plurality of channel state
information reference signals (CSI-RSs) for RLM; determining
whether a configured CSI-RS for RLM is Quasi-Co-Located (QCLed) to
any CORESET according to the resource information of the CSI-RSs;
and performing RLM measurements using the configured CSI-RS for RLM
only when the configured CSI-RS for RLM is QCLed to at least one
CORESET.
2. The method of claim 1, wherein the determining of whether the
configured CSI-RS for RLM is QCLed to any CORESET is according to
time, frequency resource location, and QCL information for CSI-RS
based RLM included in the resource information.
3. The method of claim 1, wherein the determining of whether the
configured CSI-RS for RLM is QCLed to any CORESET comprises
determining whether receiving a CORESET with reference to at least
one of Doppler shift, Doppler spread, average delay and delay
spread of the configured CSI-RS for RLM in a first frequency range
(FR1) as defined in a 3rd-Generation Partnership Project (3GPP)
specification.
4. The method of claim 3, wherein the FR1 as defined in a
3rd-Generation Partnership Project (3GPP) specification includes
sub7 GHz band.
5. The method of claim 1, wherein the determining of whether the
configured CSI-RS for RLM is QCLed to any CORESET comprises
determining whether receiving a CORESET with reference to at least
one of Doppler shift, Doppler spread, average delay, delay spread
and spatial RX parameters of the configured CSI-RS for RLM in a
second frequency range (FR2) as defined in a 3rd-Generation
Partnership Project (3GPP) specification.
6. The method of claim 5, wherein the FR2 as defined in a
3rd-Generation Partnership Project (3GPP) specification includes
millimeter Wave band.
7. A method, comprising: receiving synchronization signal block
(SSB) configuration for radio link monitoring (RLM) by a user
equipment (UE) in a new radio (NR) network, wherein the SSB
occupies a first OFDM symbol having a first numerology; receiving
channel state information reference signal (CSI-RS) configuration
for RLM by the UE, wherein the configured CSI-RS resource is
allocated over a second OFDM symbol having a second numerology;
determining whether the SSB and the configured CSI-RS resource are
Time Division Multiplexed (TDMed) responsive to the first
numerology and the second numerology being different; and
performing SSB based RLM and CSI-RS based RLM using the SSB and
CSI-RS configuration for RLM based on whether the SSB and the
configured CSI-RS resource are TDMed.
8. The method of claim 7, wherein the first numerology and the
second numerology being different includes the first numerology and
the second numerology having different subcarrier spacing (SCS)
values.
9. The method of claim 7, wherein the first numerology and the
second numerology being different includes the first numerology and
the second numerology having different cyclic-shift prefix (CP)
lengths.
10. The method of claim 7, wherein the performing SSB based RLM and
CSI-RS based RLM based on whether the SSB and the configured CSI-RS
resource are TDMed includes performing SSB based RLM and CSI-RS
based RLM only when the SSB and the configured CSI-RS resource are
TDMed.
11. The method of claim 7, wherein the performing SSB based RLM and
CSI-RS based RLM is further based on whether the UE supports
simultaneous reception over different numerologies.
12. The method of claim 11, wherein the performing SSB based RLM
and CSI-RS based RLM based on whether the UE supports simultaneous
reception over different numerologies includes performing SSB based
RLM and CSI-RS based RLM only when the UE does NOT support
simultaneous reception over different numerologies.
13. The method of claim 7, wherein the determining of whether the
SSB and the configured CSI-RS resource are TDMed includes
determining whether the SSB and the configured CSI-RS resource are
completely not overlapped in time domain.
14. A method, comprising: receiving synchronization signal block
(SSB) measurement timing configuration (SMTC) for radio link
monitoring (RLM) by a user equipment (UE) in a new radio (NR)
network; determining an RLM evaluation period according to the SMTC
configuration for RLM based at least on an SMTC periodicity; and
performing RLM using the determined RLM evaluation period.
15. The method of claim 14, wherein the SMTC configuration
comprises an SMTC periodicity, an SMTC window duration, and a
timing offset.
16. The method of claim 15, wherein a first smtc1 and a second
smtc2 are configured by the network, and wherein the RLM evaluation
period is determined based on the shortest SMTC periodicity.
17. The method of claim 16, wherein the shortest SMTC periodicity
is the smtc2 periodicity.
18. The method of claim 15, wherein a first smtc1 and a second
smtc2 are configured by the network, and wherein the RLM evaluation
period is determined based on the smtc2 periodicity.
19. The method of claim 14, wherein the determining the RLM
evaluation period is further based on an RLM evaluation scaling
factor for channel state information reference signal (CSI-RS)
based RLM, and the RLM evaluation scaling factor is associated with
whether CSI-RS resources and SMTC window durations are
overlapped.
20. The method of claim 19, wherein a CSI-RS resource and an SMTC
window duration are considered overlapped as long as the CSI-RS
resource is allocated within the SMTC window duration.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C. .sctn. 119
U.S. provisional application 62/688,450 entitled "Method for NR RLM
and Evaluation Determination" filed on Jun. 22, 2018, the subject
matter of which is incorporated herein by reference.
TECHNICAL FIELD
[0002] The disclosed embodiments relate generally to wireless
communication, and, more particularly, to method and apparatus for
radio link monitoring (RLM) based on Channel State Information
reference signal (CSI-RS) in new radio (NR) systems.
BACKGROUND
[0003] The wireless communications network has grown exponentially
over the years. A Long-Term Evolution (LTE) system offers high peak
data rates, low latency, improved system capacity, and low
operating cost resulting from simplified network architecture. LTE
systems, also known as the 4G system, also provide seamless
integration to older wireless network, such as GSM, CDMA and
Universal Mobile Telecommunication System (UMTS). In LTE systems,
an evolved universal terrestrial radio access network (E-UTRAN)
includes a plurality of evolved Node-Bs (eNodeBs or eNBs)
communicating with a plurality of mobile stations, referred to as
user equipments (UEs). The 3.sup.rd generation partner project
(3GPP) network normally includes a hybrid of 2G/3G/4G systems. The
Next Generation Mobile Network (NGMN) board, has decided to focus
the future NGMN activities on defining the end-to-end requirements
for 5G new radio (NR) systems.
[0004] For radio link monitoring (RLM) in NR, UE can be configured
to measure synchronization signal (SS) blocks (SSB) and/or channel
state information (CSI) reference signals (CSI-RS) to monitor radio
link quality. In NR, SMTC (SSB measurement timing configuration) is
provided for SSB RLM evaluation period determination. If multiple
SMTC are present, how to determine the evaluation period for the
overlap between RLM-RS and SMTC is ambiguous. How to map CSI-RS
based RLM-RS into to one COntrol REsource SET (CORESET) for
Physical downlink control channel (PDCCH) parameters determination
is undefined. How to handle RLM when SSB for RLM and RLM CSI-RS
resources are configured with different numerologies is undefined.
Finally, the definition of overlapping between CSI-RS resource and
SMTC window duration is ambiguous so that RLM measurement behavior
is also ambiguous.
[0005] A solution is sought to define UE behavior for performing NR
RLM.
SUMMARY
[0006] Methods are proposed to define UE behavior for performing
synchronization signal block (SSB) based radio link monitoring
(RLM) and channel state information reference signal (CSI-RS) based
RLM. In a first novel aspect, if CSI-RS based RLM-RS is not QCLed
to any CORESET, then UE determines that CSI-RS RLM configuration is
error and does not perform RLM accordingly. In a second novel
aspect, SSB for RLM and RLM CSI-RS resources are configured with
different numerologies. UE perform SSB based RLM and CSI-RS based
RLM based on whether the SSB and CSI-RS resources are TDMed
configured by the network. In a third novel aspect, when multiple
SMTC configurations are configured to UE, UE determines an SMTC
period and whether SMTC and RLM-RS are overlapped for the purpose
of RLM evaluation period determination.
[0007] In one embodiment, a UE receives core resource set (CORESET)
configuration in a new radio (NR) network. The CORESET
configuration comprises one or more CORESETs for the UE. The UE
receives radio link monitoring (RLM) configuration comprising
resource information of a plurality of channel state information
reference signals (CSI-RSs) for RLM. The UE determines whether a
configured CSI-RS for RLM is Quasi-Co-Located (QCLed) to any
CORESET according to the resource information of the CSI-RSs. The
UE performs RLM measurements using the configured CSI-RS for RLM
only when the configured CSI-RS for RLM is QCLed to at least one
CORESET.
[0008] In another embodiment, UE receives synchronization signal
block (SSB) configuration for radio link monitoring (RLM) in a new
radio (NR) network. The SSB occupies a first OFDM symbol having a
first numerology. The UE receives channel state information
reference signal (CSI-RS) configuration for RLM. The configured
CSI-RS resource is allocated over a second OFDM symbol having a
second numerology. The UE determines whether the SSB and the
configured CSI-RS resource are TDMed responsive to the first
numerology and the second numerology being different. The UE
performs SSB based RLM and CSI-RS based RLM using the SSB and
CSI-RS configuration for RLM and based on whether the SSB and the
configured CSI-RS resource are TDMed.
[0009] In another embodiment, UE receives synchronization signal
block (SSB) measurement timing configuration (SMTC) for radio link
monitoring (RLM) in a new radio (NR) network. The UE determines an
RLM evaluation period according to the SMTC configuration based at
least on an SMTC periodicity. The UE performs CSI-RS based RLM
using the determined RLM evaluation period.
[0010] Other embodiments and advantages are described in the
detailed description below. This summary does not purport to define
the invention. The invention is defined by the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The accompanying drawings, where like numerals indicate like
components, illustrate embodiments of the invention.
[0012] FIG. 1 illustrates a system diagram of a new radio (NR)
wireless system with SSB and CSI-RS configured for radio link
monitoring (RLM) in accordance with embodiments of the current
invention.
[0013] FIG. 2 shows simplified block diagrams of a UE and a BS in
accordance with embodiments of the current invention.
[0014] FIG. 3 illustrates control resource set (CORESET)
configuration and CSI-RS configuration for RLM and their
relationship in accordance with one novel aspect of the present
invention.
[0015] FIG. 4 illustrates SSB based RLM-RS and CSI-RS based RLM-RS
configured with different numerologies and corresponding RLM
mechanism.
[0016] FIG. 5 illustrates RLM evaluation period determination based
on SMTC configuration in accordance with one novel aspect of the
present invention.
[0017] FIG. 6 illustrates one embodiment of determining whether
SMTC and RLM-RS are overlapped for determining RLM evaluation
period length.
[0018] FIG. 7 is a flow chart of a method for CSI-RS based RLM
measurements and in accordance with embodiments of the current
invention.
[0019] FIG. 8 is a flow chart of a method for SSB based and CSI-RS
based RLM measurements in accordance with embodiments of the
current invention.
[0020] FIG. 9 is a flow chart of a method for RLM and RLM
evaluation period determination in accordance with embodiments of
the current invention.
DETAILED DESCRIPTION
[0021] Reference will now be made in detail to some embodiments of
the invention, examples of which are illustrated in the
accompanying drawings.
[0022] FIG. 1 illustrates a system diagram of a new radio (NR)
wireless system 100 with synchronization signal block (SSB) and
channel state information reference signal (CSI-RS) configured for
radio link monitoring (RLM) in accordance with embodiments of the
current invention. Wireless communication system 100 comprises one
or more wireless networks having fixed base infrastructure units,
such as receiving wireless communications devices or base units 102
103, and 104, forming wireless radio access networks (RANs)
distributed over a geographical region. The base units may also be
referred to as an access point (AP), an access terminal, a base
station (BS), a Node-B, an eNodeB, an eNB, a gNodeB, a gNB, or by
other terminology used in the art. Each of the base unit 102, 103,
and 104 serves a geographic area and connects to a core network 109
e.g., via links 116, 117, and 118 respectively. The base unit
performs beamforming in the NR system, e.g., in both FR1 (sub7 GHz
spectrum) or FR2 (Millimeter Wave frequency spectrum). Backhaul
connections 113, 114 and 115 connect the non-co-located receiving
base units, such as 102, 103, and 104. These backhaul connections
can be either ideal or non-ideal.
[0023] A wireless communications device UE 101 in wireless system
100 is served by base station 102 via uplink 111 and downlink 112.
Other UEs 105, 106, 107, and 108 are served by different base
stations. UEs 105 and 106 are served by base station 102. UE 107 is
served by base station 104. UE 108 is served by base station 103.
Each UE may be a smart phone, a wearable device, an Internet of
Things (IoT) device, a tablet, etc. For radio link monitoring (RLM)
in NR, each UE can be configured to measure synchronization signal
(SS) blocks (SSB) and/or channel state information (CSI) reference
signal (CSI-RS). With explicit signaling, after UE is connected to
a cell, the RLM RS configuration parameters can be configured
through radio resource control (RRC) signaling via
RadioLinkMonitoringRS, including RS type (SSB or CSI-RS) and RS ID.
For CSI-RS, the parameters include CSI-RS Index that is linked to
CSI-RS resource configuration, which further includes resource
location in time and frequency domain and quasi-co-location (QCL)
info through beam indication or transmission configuration
indication (TCI) state. For SSB, the parameters include SSB Index
that is used to derive SSB location in time domain. There is no QCL
info for SSB. RLM RS configuration parameters can also be
configured via implicit signaling, e.g., using the RS in TCI state
of a COntrol REsource SET (CORESET) when no dedicated signaling for
RLM in RRC is available (i.e., RadioLinkMonitoringRS is
missing).
[0024] There are certain issues for SSB based RLM and CSI-RS based
RLM in NR systems. First, SMTC (SSB measurement timing
configuration) is provided for SSB RLM evaluation period
determination. If multiple SMTC are present, how to determine the
evaluation period for the overlap between RLM-RS and SMTC is
ambiguous. Second, how to map CSI-RS based RLM-RS to one COntrol
REsource SET (CORESET) for PDCCH parameter determination is
undefined. Third, how to handle RLM when SSB for RLM and RLM CSI-RS
resources are configured with different numerologies is undefined.
Fourth, the definition of overlapping between CSI-RS resource and
SMTC window duration is ambiguous so that RLM behavior, e.g., how
to determine the RLM evaluation period is also ambiguous.
[0025] In accordance with one novel aspect, methods are proposed to
define UE behavior for performing SSB based RLM and CSI-RS based
RLM. In a first novel aspect, if CSI-RS based RLM-RS is not QCLed
to any CORESET, then UE determines that CSI-RS RLM configuration is
error and does not perform RLM accordingly. In a second novel
aspect, SSB for RLM and RLM CSI-RS resources are configured with
different numerologies (i.e., different SCS, CP). UE will perform
SSB based RLM and CSI-RS based RLM only when the SSB and the
configured CSI-RS resource are TDMed configured by the network. In
a third novel aspect, when multiple SMTC configurations are
configured to UE, UE determines an SMTC period for the purpose of
RLM evaluation period. UE also determines whether SMTC window
duration and RLM-RS resource are overlapped for the purpose of
determining the RLM evaluation period.
[0026] FIG. 2 shows simplified block diagrams of a wireless
devices, e.g., UE 201 and base station 202 in accordance with the
current invention. Base station 202 has an antenna 226, which
transmits and receives radio signals. A RF transceiver module 223,
coupled with the antenna, receives RF signals from antenna 226,
converts them to baseband signals and sends them to processor 222.
RF transceiver 223 also converts received baseband signals from
processor 222, converts them to RF signals, and sends out to
antenna 226. Processor 222 processes the received baseband signals
and invokes different functional modules to perform features in
base station 202. Memory 221 stores program instructions and data
224 to control the operations of base station 202. Base station 202
also includes a set of control modules and circuits, such as an RLM
circuit 281 that performs RLM and an RLM configuration circuit 282
that configures RLM for UEs and communicates with UEs to implement
the RLM functions.
[0027] Similarly, UE 201 has an antenna 235, which transmits and
receives radio signals. A RF transceiver module 234, coupled with
the antenna, receives RF signals from antenna 235, converts them to
baseband signals and sends them to processor 232. RF transceiver
234 also converts received baseband signals from processor 232,
converts them to RF signals, and sends out to antenna 235.
Processor 232 processes the received baseband signals and invokes
different functional modules to perform features in mobile station
201. Memory 231 stores program instructions and data 236 to control
the operations of mobile station 201. Suitable processors include,
by way of example, a special purpose processor, a digital signal
processor (DSP), a plurality of micro-processors, one or more
micro-processor associated with a DSP core, a controller, a
microcontroller, application specific integrated circuits (ASICs),
file programmable gate array (FPGA) circuits, and other type of
integrated circuits (ICs), and/or state machines.
[0028] UE 201 also includes a set of control modules and circuits
that carry out functional tasks. These functions can be implemented
in software, firmware and hardware. A processor in associated with
software may be used to implement and configure the functional
features of UE 201. For example, an SSB based RLM configuration
circuit 291 that configures SSB and SMTC windows for RLM; a CSI-RS
based RLM configuration circuit 292 that configures CSI-RS resource
for RLM; an RLM control and handling circuit 293 that determines
whether and how to perform RLM based on the RLM configuration; an
RLM report circuit 294 transmits RLM related reports to the
network.
[0029] FIG. 3 illustrates control resource set (CORESET)
configuration and CSI-RS configuration for RLM and their
relationship in accordance with one novel aspect of the present
invention. As shown in FIG. 3, a base station can configure more
than one CORESET for one UE, e.g., CORESET1 (610) and CORESET2
(620). The CORESETs are configured by the network through RRC
signaling after UE is connected to a cell (i.e., UE only knows SMTC
of the serving cell). The configuration parameters for CORESET
include TCI state and CORESET ID. A TCI state indicates RS ID
(i.e., CSI-RS ID or SSB index) and associated QCL type. A CORESET
ID indicates the frequency domain resource location, duration,
precoder, mapping type etc. of the CORESET. UE can determine
CORESET based on different priority rules, e.g., based on CORESET
index QCLed with the CSI-RS based RLM-RS.
[0030] In general, determining whether CSI-RS for RLM is QCLed to
any CORESET requires time, frequency resource location, and QCL
information. However, in some situations, UE may find that the
CSI-RS based RLM-RS is not QCLed to any CORESET. Under such
condition, UE can determine that the CSI-RS RLM configuration is
error and does not perform the corresponding RLM functionality.
This is because if the CSI-RS based RLM-RS is not QCLed to any
CORESET, then the UE does not know how to receive control
parameters over PDCCH. The 3GPP specification defines a first
frequency range (FR1) and a second frequency range (FR2). In FR1
(e.g., sub7 GHz), QCL information comprises the reference for
Doppler shift, Doppler spread, average delay and delay spread of
the configured CSI-RS for RLM. In FR2 (e.g., mmWave), QCL
information further includes spatial RX parameters, e.g. the RX
beam. Therefore, QCL information in FR2 may be called spatial QCL
information, and QCLed means the same RX beam.
[0031] FIG. 4 illustrates SSB based RLM-RS and CSI-RS based RLM-RS
configured with different numerologies and corresponding RLM
mechanism. In NR, different numerologies are supported with
different OFDM frame format, e.g., different subcarrier spacing
(SCS), and cyclic prefix (CP) length. Different SCS may include 60
KHz, 120 KHz, 240 KHz, 480 KHz, etc. CSI-RS based RLM-RS and SSB
based RLM-RS are configurable over the same or different OFDM
symbols having the same or different numerologies. As shown in FIG.
4, CSI-RS based RLM-RS and SSB based RLM-RS are multiplexed in the
same OFDM symbol but do not have the same SCS, and UE may not
support simultaneous receiving over different numerologies. For
example, in the same OFDM symbol, CSI-RS based RLM-RS is configured
with SCS=60 KHz, and SSB based RLM-RS is configured with SCS=120
kHz.
[0032] When UE does not support simultaneous reception over
different numerologies (e.g., different SCS or different CP
length), SSB for RLM and RLM CSI-RS resources should be TDMed
configured to UE. UE will not perform SSB based RLM and CSI-RS
based RLM simultaneously. Instead, UE performs SSB based RLM or
CSI-RS based RLM one at a time. Note the definition for TDMed
configuration means that the configured SSB and CSI-RS resources
should be completely not overlapped in time domain, e.g., they do
not have any overlapping in time domain. In other words, the
configured SSB and CSI-RS resources should not have any overlapping
and should not have any partial overlapping, especially when the
OFDM symbol lengths for SSB and CSI-RS resources are different.
[0033] For RLM, UE needs to evaluate whether the downlink radio
link quality on the configured RLM-RS resource estimated over a
first evaluation period becomes worse than a first threshold within
the first evaluation period T.sub.EVALUATE_out_SSB. UE also needs
to evaluate whether the downlink radio link quality on the
configured RLM-RS resource estimated over a second evaluation
period becomes better than a second threshold within the second
evaluation period T.sub.EVALUATE_in_SSB For FR1 and FR2, the length
of the evaluation period depends on N (RX beam scaling factor) and
P (evaluation scaling factor), which in turn depends on how RLM-RS
resources and SMTC occasions are configured for UE. SMTC is
configured by the network through System Information or RRC
signaling after UE is connected to the network (i.e., UE can know
SMTC of other cells. The configuration parameters for SMTC include
offset, duration, and periodicity. In general, SSBs inside SMTC are
used for L3 measurements, and SSBs outside SMTC are used for L1
measurements (e.g., RLM).
[0034] Both T.sub.EVALUATE_out_SSB and T.sub.EVALUATE_in_SSB are
defined for FR1 and FR2 in the 3GPP specification. For FR1,
P=1/(1-T.sub.SSB/MGRP), when in the monitored cell there are
measurement gaps configured for intra-frequency, inter-frequency or
inter-RAT measurements, which are overlapping with some but not all
occasions of the SSB; P=1, when the monitored cell there are no
measurement gaps overlapping with any occasion of the SSB. For FR2,
P=1/(1-T.sub.SSB/T.sub.SMTCperiod), when RLM-RS is not overlapped
with measurement gap and RLM-RS is partially overlapped with SMTC
occasion (T.sub.SSB<T.sub.SMTCperiod); P=3, when RLM-RS is not
overlapped with measurement gap and RLM-RS is fully overlapped with
SMTC period (T.sub.SSB=T.sub.SMTCperiod);
P=1/(1-T.sub.SSB/MGRP-T.sub.SMTCperiod), when RLM-RS is partially
overlapped with measurement gap and RLM-RS is partially overlapped
with SMTC occasion (T.sub.SSB<T.sub.SMTCperiod) and SMTC
occasion is not overlapped with measurement gap and
(T.sub.SMTperiod.noteq.MGRP) or (T.sub.SMTCperiod=MGRP and
TSSB<0.5*T.sub.SMTCperiod); P=1/(1-T.sub.SSB/MGRP)*3, when
RLM-RS is partially overlapped with measurement gap and partially
overlapped with SMTC occasion (T.sub.SSB<T.sub.SMTCperiod) and
SMTC occasion is not overlapped with measurement gap and
T.sub.SMTCperiod=MGRP and T.sub.SSB=0.5*T.sub.SMTCperiod;
P=1/{1-T.sub.SSB/min (T.sub.SMTCperiod, MGRP)}, when RLM-RS is
partially overlapped with measurement gap and RLM-RS is partially
overlapped with SMTC occasion (T.sub.SSB<T.sub.SMTCperiod) and
SMTC occasion is partially or fully overlapped with measurement
gap; P=1/(1-T.sub.SSB/MGRP)*3, when RLM-RS is partially overlapped
with measurement gap and RLM-RS is fully overlapped with SMTC
occasion (T.sub.SSB=T.sub.SMTCperiod) and SMTC occasion is
partially overlapped with measurement gap
(T.sub.SMTCperiod<MGRP). Similarly, the above definition also
works for CSI-RS based RLM, it reuses the evaluation time by
replacing T.sub.SSB.fwdarw.T.sub.CSI-RS.
[0035] FIG. 5 illustrates RLM evaluation period determination based
on RLM-RS and SMTC configuration in accordance with one novel
aspect of the present invention. As explained above, when RLM-RS
collides with SMTC occasion in FR2, the evaluation scaling factor P
is introduced and it depends on the measurement gap (MGRP), the
RLM-RS (SSB) periodicity (T.sub.SSB), and the SMTC periodicity
(T.sub.SMTCperiod). As depicted in 510, RLM-RS are fully overlapped
with SMTC2; while as depicted in 520, RLM-RS are partially
overlapped with SMTC1. However, multiple SMTC may be configured.
For example, smtc1 is the primary measurement timing configuration.
In addition, smtc2 is the secondary measurement timing
configuration, for SS corresponding to a measurement object with
PCI listed in PCI-List. For these SS, the periodicity is indicated
by periodicity in smtc2 and the timing offset is equal to the
offset indicated by periodicityAndOffset modulo periodicity. The
periodicity in smtc2 can only be set to a value strictly shorter
than the periodicity indicated by periodicityAndOffset in smtc1
(e.g. if periodicityAndOffset indicates sf10, periodicity can only
be set of sf5, if periodicityAndOffset indicates sf5, smtc2 cannot
be configured). If smtc2 is present, UE is configured with two SMTC
configurations. These two SMTCs, smtc1 and smtc2, must have same
Duration and Offset but they may have different Periodicity values.
Accordingly, if smtc2 is present, to avoid ambiguity on deriving
the evaluation scaling factor P in FR2, the T.sub.SMTCperiod is set
to be equal to min (smtc1 Periodicity, smtc2 Periodicity). In one
preferred embodiment, SMTC2 is always shorter than SMTC1, e.g. min
(smtc1 Periodicity, smtc2 Periodicity)=smtc2 Periodicity. In
another preferred embodiment, the T.sub.SMTCperiod is simply set to
be equal to smtc2 Periodicity, regardless of the Periodicity values
of smtc1 and smtc2. This way, if both smtc1 and smtc2 are present,
then the periodicity of smtc2 can simply be chosen as the
T.sub.SMTCperiod.
[0036] FIG. 6 illustrates one embodiment of determining whether
SMTC and CSI-RS based RLM-RS are overlapped for determining RLM
evaluation period length. The evaluation scaling factor P depends
on whether SMTC occasion and CSI-RS based RLM-RS are overlapped or
not. However, the definition on overlap between CSI-RS based RLM-RS
and SMTC occasion is ambiguous so that determination of CSI-RS
based RLM evaluation period remains ambiguous. There can be
different scenarios of how RLM CSI-RS and SMTC are overlapped. In a
first scenario, as depicted by CSI-RS 610, the CSI-RS resource is
located within the SMTC window duration. In a second scenario,
CSI-RS 620 resource is located within the SMTC window duration and
also within an SSB. In a third scenario, CSI-RS 630 resource is
located within the SMTC window duration, but also within a
scheduling availability. Accordingly, UE determines that the SMTC
window duration and the CSI-RS based RLM-RS are overlapped as long
as the RLM CSI-RS resource is within the SMTC window duration,
regardless whether the RLM CSI-RS is located within an SSB or
located within a scheduling availability inside SMTC occasion.
[0037] FIG. 7 is a flow chart of a method for CSI-RS based RLM
measurements and in accordance with embodiments of the current
invention. In step 701, a UE receives core resource set (CORESET)
configuration in a new radio (NR) network. The CORESET
configuration comprises one or more CORESETs for the UE. In step
702, the UE receives radio link monitoring (RLM) configuration
comprising resource information of a plurality of channel state
information reference signals (CSI-RSs) for RLM. In step 703, the
UE determines whether a configured CSI-RS for RLM is
Quasi-Co-Located (QCLed) to any CORESET according to the resource
information of the CSI-RSs. In step 704, the UE performs RLM
measurements using the configured CSI-RS for RLM only when the
configured CSI-RS for RLM is QCLed to at least one CORESET.
[0038] FIG. 8 is a flow chart of a method for SSB based and CSI-RS
based RLM measurements in accordance with embodiments of the
current invention. In step 801, a UE receives synchronization
signal block (SSB) configuration for radio link monitoring (RLM) in
a new radio (NR) network. The SSB occupies a first OFDM symbol
having a first numerology. In step 802, the UE receives channel
state information reference signal (CSI-RS) configuration for RLM.
The configured CSI-RS resource is allocated over a second OFDM
symbol having a second numerology. In step 803, the UE determines
whether the SSB and the configured CSI-RS resource are time
division multiplexed (TDMed) responsive to the first numerology and
the second numerology being different. In step 804, the UE performs
SSB based RLM and CSI-RS based RLM using the SSB and CSI-RS
configuration for RLM and based on whether the SSB and the CSI-RS
resource are TDMed.
[0039] FIG. 9 is a flow chart of a method for RLM and RLM
evaluation period determination in accordance with embodiments of
the current invention. In step 901, a UE receives synchronization
signal block (SSB) measurement timing configuration (SMTC) for
radio link monitoring (RLM) in a new radio (NR) network. In step
902, the UE determines an RLM evaluation period according to the
SMTC configuration based at least on an SMTC periodicity. In step
903, the UE performs CSI-RS based RLM using the determined RLM
evaluation period.
[0040] Although the present invention has been described in
connection with certain specific embodiments for instructional
purposes, the present invention is not limited thereto.
Accordingly, various modifications, adaptations, and combinations
of various features of the described embodiments can be practiced
without departing from the scope of the invention as set forth in
the claims.
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