U.S. patent application number 16/276777 was filed with the patent office on 2019-06-13 for radio terminal, radio access networ node, and method therefor.
This patent application is currently assigned to NEC Corporation. The applicant listed for this patent is NEC Corporation. Invention is credited to Hisashi FUTAKI.
Application Number | 20190182000 16/276777 |
Document ID | / |
Family ID | 66438281 |
Filed Date | 2019-06-13 |
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United States Patent
Application |
20190182000 |
Kind Code |
A1 |
FUTAKI; Hisashi |
June 13, 2019 |
RADIO TERMINAL, RADIO ACCESS NETWOR NODE, AND METHOD THEREFOR
Abstract
A radio terminal (12) transmits, to a radio access network (RAN)
node (11) in a radio access network (RAN), an indication indicating
whether a measurement gap for inter-bandwidth part (BWP)
measurement among BWPs included in a plurality of downlink BWPs is
required. The downlink BWPs are included within one system
bandwidth. Further, the radio terminal (12) receives, from the RAN
node (11), a measurement configuration including a measurement gap
configuration for one or more BWPs included in the downlink BWPs.
It is thus, for example, possible to allow a radio terminal to be
configured with a proper measurement gap for inter-BWP measurement
within one carrier bandwidth.
Inventors: |
FUTAKI; Hisashi; (Tokyo,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NEC Corporation |
Tokyo |
|
JP |
|
|
Assignee: |
NEC Corporation
Tokyo
JP
|
Family ID: |
66438281 |
Appl. No.: |
16/276777 |
Filed: |
February 15, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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PCT/JP2018/030311 |
Aug 14, 2018 |
|
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16276777 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 36/0088 20130101;
H04W 36/06 20130101; H04L 5/0092 20130101; H04L 5/0046 20130101;
H04L 5/0039 20130101; H04L 5/005 20130101; H04W 24/10 20130101;
H04W 76/27 20180201; H04L 1/0693 20130101; H04W 72/0453 20130101;
H04W 48/12 20130101; H04L 5/0053 20130101; H04W 36/165
20130101 |
International
Class: |
H04L 5/00 20060101
H04L005/00; H04W 24/10 20060101 H04W024/10; H04L 1/06 20060101
H04L001/06; H04W 76/27 20060101 H04W076/27; H04W 36/16 20060101
H04W036/16; H04W 72/04 20060101 H04W072/04 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 13, 2017 |
JP |
2017-218039 |
Claims
1. A method for a User Equipment (UE), the method comprising:
receiving a Radio Resource Control (RRC) Reconfiguration message
that includes first configuration information corresponding to a
first bandwidth part and second configuration information
corresponding to a second bandwidth part; monitoring a radio link
on the first bandwidth part based on first Radio Link Monitoring
(RLM) configuration information included in the received first
configuration information if an active bandwidth part of the UE is
the first bandwidth part; receiving Downlink Control Information
(DCI) on Physical Downlink Control Channel (PDCCH); switching,
based on the received DCI, the active bandwidth part of the UE from
the first bandwidth part to the second bandwidth part; and
monitoring a radio link on the second bandwidth part based on
second RLM configuration information included in the received
second configuration information if the active bandwidth part of
the UE is the second bandwidth part.
2. The method according to claim 1, wherein each of the first and
the second RLM configuration information includes information of a
reference signal that the UE uses for the RLM, wherein the
reference signal is either Synchronization Signal/Physical
Broadcast Channel block (SSB) or Channel State Information
Reference Signal (CSI-RS).
3. The method according to claim 1, wherein either the first or the
second bandwidth part is an initial bandwidth part,
4. A method for a base station, the method comprising:
transmitting, to a User Equipment (UE), a Radio Resource Control
(RRC) Reconfiguration message that includes first configuration
information corresponding to a first bandwidth part and second
configuration information corresponding to a second bandwidth part,
wherein the first configuration information includes first Radio
Link Monitoring (RLM) configuration information which is used by
the UE to monitor a radio link on the first bandwidth part if an
active bandwidth part of the UE is the first bandwidth part, and
the second configuration information includes second RLM
configuration information which is used by the UE to monitor a
radio link on the second bandwidth part if the active bandwidth
part of the UE is the second bandwidth part; and transmitting, to
the UE, Downlink Control Information (DCI) on Physical Downlink
Control Channel (PDCCH), the DCI causing the UE to switch the
active bandwidth part of the UE from the first bandwidth part to
the second bandwidth part.
5. The method according to claim 4, wherein each of the first and
the second RLM configuration information includes information of a
reference signal that the UE uses for the RLM, wherein the
reference signal is either Synchronization Signal/Physical
Broadcast Channel block (SSB) or Channel State Information
Reference Signal (CSI-RS).
6. The method according to claim 4, wherein either the first or the
second bandwidth part is an initial bandwidth part.
7. A User Equipment comprising: a transceiver; and a processor
configured to: receive, via the transceiver, a Radio Resource
Control (RRC) Reconfiguration message that includes first
configuration information corresponding to a first bandwidth part
and second configuration information corresponding to a second
bandwidth part, monitor a radio link on the first bandwidth part
based on first Radio Link Monitoring (RLM) configuration
information included in the received first configuration
information if an active bandwidth part of the UE is the first
bandwidth part, receive, via the transceiver, Downlink Control
Information (DCI) on Physical Downlink Control Channel (PDCCH),
switch, based on the received DCI, the active bandwidth part of the
UE from the first bandwidth part to the second bandwidth part, and
monitor a radio link on the second bandwidth part based on second
RLM configuration information included in the received second
configuration information if the active bandwidth part of the UE is
the second bandwidth part.
8. A base station comprising: a transceiver; and a processor
configured to: transmit, to a User Equipment (UE) via the
transceiver, a Radio Resource Control (RRC) Reconfiguration message
that includes first configuration information corresponding to a
first bandwidth part and second configuration information
corresponding to a second bandwidth part, wherein the first
configuration information includes first Radio Link Monitoring
(RLM) configuration information which is used by the UE to monitor
a radio link on the first bandwidth part if an active bandwidth
part of the UE is the first bandwidth part, and the second
configuration information includes second RLM configuration
information which is used by the UE to monitor a radio link on the
second bandwidth part if the active bandwidth part of the UE is the
second bandwidth part; and transmit, to the UE via the transceiver,
Downlink Control Information (DCI) on Physical Downlink Control
Channel (PDCCH), the DCI causing the UE to switch the active
bandwidth part of the UE from the first bandwidth part to the
second bandwidth part.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation application of
International Application No. PCT/JP2018/030311 filed on Aug. 14,
2018, which claims the benefit of priority from Japanese Patent
Application No. 2017-218039 filed on Nov. 13, 2017, the disclosures
of each of which are incorporated herein by reference.
TECHNICAL FIELD
[0002] The present disclosure relates to a radio communication
system and, in particular, to a radio communication system using
one or more bandwidth parts configured within one carrier
bandwidth.
BACKGROUND ART
[0003] The 3rd Generation Partnership Project (3GPP) has been
working on the standardization for the fifth generation mobile
communication system (5G) to make 5G a commercial reality in 2020
or later. 5G is expected to be realized by continuous
enhancement/evolution of LTE and LTE-Advanced and an innovative
enhancement/evolution by an introduction of a new 5G air interface
(i.e., a new Radio Access Technology (RAT)). The new RAT supports,
for example, frequency bands higher than the frequency bands (e.g.,
6 GHz or lower) supported by LTE/LTE-Advanced and its continuous
evolution. For example, the new RAT supports centimeter-wave bands
(10 GHz or higher) and millimeter-wave bands (30 GHz or
higher).
[0004] In this specification, the fifth generation mobile
communication system is referred to as a 5G System or a Next
Generation (NextGen) System (NG System). The new RAT for the 5G
System is referred to as a New Radio (NR), a 5G RAT, or a NG RAT. A
new Radio Access Network (RAN) for the 5G System is referred to as
a 5G-RAN or a NextGen RAN (NG RAN). A new base station in the
NG-RAN is referred to as a NR NodeB (NR NB) or a gNodeB (gNB). A
new core network for the 5G System is referred to as a 5G Core
Network (5G-CN or 5GC) or a NextGen Core (NG Core). A radio
terminal (i.e., User Equipment (UE)) capable of being connected to
the 5G System is referred to as 5G UE or NextGen UE (NG UE), or
simply referred to as UE. The official names of the RAT, UE, radio
access network, core network, network entities (nodes), protocol
layers and the like for the NG System will be determined in the
future as standardization work progresses.
[0005] The term "LTE" used in this specification includes
enhancement/evolution of LTE and LTE-Advanced to provide
interworking with the 5G System, unless otherwise specified. The
enhancement/evolution of LTE and LTE-Advanced for the interworking
with the 5G System is referred to as LTE-Advanced Pro, LTE+, or
enhanced LTE (eLTE). Further, terms related to LTE networks and
logical entities used in this specification, such as "Evolved
Packet Core (EPC)", "Mobility Management Entity (MME)", "Serving
Gateway (S-GW)", and "Packet Data Network (PDN) Gateway (P-GW))",
include their enhancement/evolution to provide interworking with
the 5G System, unless otherwise specified. Enhanced EPC, enhanced
MME, enhanced S-GW, and enhanced P-GW are referred to, for example,
as enhanced EPC (eEPC), enhanced MME (eMME), enhanced S-GW (eS-GW),
and enhanced P-GW (eP-GW), respectively.
[0006] In LTE and LTE-Advanced, for achieving Quality of Service
(QoS) and packet routing, a bearer per QoS class and per PDN
connection is used in both a RAN (i.e., an Evolved Universal
Terrestrial RAN (E-UTRAN)) and a core network (i.e., EPC). That is,
in the Bearer-based QoS (or per-bearer QoS) concept, one or more
Evolved Packet System (EPS) bearers are configured between a UE and
a P-GW in an EPC, and a plurality of Service Data Flows (SDFs)
having the same QoS class are transferred through one EPS bearer
satisfying this QoS.
[0007] In contrast, with regard to the 5G System, it is discussed
that although radio bearers may be used in the NG RAN, no bearers
are used in the 5GC or in the interface between the 5GC and the
NG-RAN. Specifically, PDU flows are defined instead of an EPS
bearer, and one or more SDFs are mapped to one or more PDU flows. A
PDU flow between a 5G UE and a user-plane terminating entity in an
NG Core (i.e., an entity corresponding to a P-GW in the EPC)
corresponds to an EPS bearer in the EPS Bearer-based QoS concept.
The PDU flow corresponds to the finest granularity of the packet
forwarding and treatment in the 5G system. That is, the 5G System
adopts the Flow-based QoS (or per-flow QoS) concept instead of the
Bearer-based QoS concept. In the Flow-based QoS concept, QoS is
handled per PDU flow. Association between a 5G UE and a data
network is referred to as a "PDU session". The term "PDU session"
corresponds to the term "PDN connection" in LTE and LTE-Advanced. A
plurality of PDU flows can be configured in one PDU session. The
3GPP specifications define a 5G QoS Indicator (5QI) corresponding
to the QCI of the LTE for the 5G system.
[0008] The PDU flow is also referred to as a "QoS flow". The QoS
flow is the finest granularity in QoS treatment in the 5G system.
User plane traffic having the same N3 marking value in a PDU
session corresponds to a QoS flow. The N3 marking corresponds to
the above-described PDU flow ID, and it is also referred to as a
QoS flow Identity (QFI) or a Flow Identification Indicator (FII).
There is one-to-one relationship (i.e., one-to-one mapping) at
least between each 5QI defined in the specification and a
corresponding QFI having the same value (or number) as this
5QI.
[0009] FIG. 1 shows a basic architecture of the 5G system. A UE
establishes one or more Signalling Radio Bearers (SRBs) and one or
more Data Radio Bearers (DRBs) with a gNB. The 5GC and the gNB
establish a control plane interface and a user plane interface for
the UE. The control plane interface between the 5GC and the gNB
(i.e., RAN) is referred to as an N2 interface, an NG2 interface or
an NG-c interface, and is used for transfer of Non-Access Stratum
(NAS) information and for transfer of control information (e.g., N2
AP Information Element) between the 5GC and the gNB. The user plane
interface between the 5GC and the gNB (i.e., RAN) is referred to as
an N3 interface, an NG3 interface or an NG-u interface, and is used
for transfer of packets of one or more PDU flows in a PDU session
of the UE.
[0010] Note that, the architecture shown in FIG. 1 is merely one of
the 5G architecture options (or deployment scenarios). The
architecture shown in FIG. 1 is referred to as "Standalone NR (in
NextGen System)" or "Option 2". The 3GPP further discusses network
architectures for multi-connectivity operations using the E-UTRA
and NR radio access technologies. A representative example of the
multi-connectivity operations is Dual Connectivity (DC) in which
one Master node (MN) and one Secondary node (SN) cooperate with
each other and simultaneously communicate with one UE. The Dual
Connectivity operation using the E-UTRA and NR radio access
technologies is referred to as Multi-RAT Dual Connectivity (MR-DC).
The MR-DC is dual connectivity between E-UTRA and NR nodes.
[0011] In the MR-DC, one of the E-UTRA node (i.e., eNB) and the NR
node (i.e., gNB) operates as a Master node (MN), while the other
one operates as a Secondary node (SN), and at least the MN is
connected to the core network. The MN provides one or more Master
Cell Group (MCG) cells to the UE, while the SN provides one or more
Secondary Cell Group (SCG) cells to the UE. The MR-DC includes
"MR-DC with the EPC" and "MR-DC with the 5GC".
[0012] The MR-DC with the EPC includes E-UTRA-NR Dual Connectivity
(EN-DC). In the EN-DC, the UE is connected to an eNB operating as
the MN and a gNB operating as the SN. Further, the eNB (i.e.,
Master eNB) is connected to the EPC, while the gNB (i.e. Secondary
gNB) is connected to the Master eNB through the X2 interface.
[0013] The MR-DC with the 5GC includes NR-E-UTRA Dual Connectivity
(NE-DC) and NG-RAN E-UTRA-NR Dual Connectivity (NG-EN-DC). In the
NE-DC, the UE is connected to a gNB operating as the MN and an eNB
operating as the SN, the gNB (i.e., Master gNB) is connected to the
5GC, and the eNB (i.e. Secondary eNB) is connected to the Master
gNB through the Xn interface. On the other hand, in the NG-EN-DC,
the UE is connected to an eNB operating as the MN and a gNB
operating as the SN, and the eNB (i.e., Master eNB) is connected to
the 5GC, and the gNB (i.e. Secondary gNB) is connected to the
Master eNB through the Xn interface.
[0014] FIGS. 2, 3 and 4 show the network configurations of the
above-described three DC types: EN-DC, NE-DC and NG-EN-DC,
respectively. Note that, although the Secondary gNB (SgNB) in the
EN-DC of FIG. 2 is also referred to as en-gNB, and the Secondary
eNB (SeNB) in the NE-DC of FIG. 3 and the Master eNB (MeNB) in the
NG-EN-DC of FIG. 4 are also referred to as ng-eNB, they are simply
referred to as gNB or eNB in this specification. The 5G System
further supports dual connectivity between two gNBs. In this
specification, dual connectivity between two gNBs is referred to as
NR-NR DC. FIG. 5 shows the network configuration of NR-NR DC.
[0015] The NR is expected to use different sets of radio parameters
in multiple frequency bands. Each radio parameter set is referred
to as "numerology". OFDM numerology for an Orthogonal Frequency
Division Multiplexing (OFDM) system includes, for example,
subcarrier spacing, system bandwidth, Transmission Time Interval
(TTI) length, subframe duration, cyclic prefix length, and symbol
duration. The 5G system supports various types of services having
different service requirements, including, for example, enhanced
Mobile Broad Band (eMBB), Ultra Reliable and Low Latency
Communication (URLLC), and M2M communication with a large number of
connections (e.g., massive Machine Type Communication (mMTC)).
Numerology selection depends on service requirements.
[0016] The UE and the NR gNB in the 5G system support aggregation
of multiple NR carriers with different numerologies. The 3GPP
discusses achievement of aggregation of multiple NR carriers (or NR
cells) with different numerologies by lower layer aggregation, such
as the existing LTE Carrier Aggregation (CA), or higher layer
aggregation, such as the existing Dual Connectivity.
[0017] The 5G NR supports channel bandwidths wider than those of
the LTE (e.g., 100 s of MHz). One channel bandwidth (i.e., a
BW.sub.Channel) is a radio frequency (RF) bandwidth supporting one
NR carrier. The channel bandwidth is also referred to as a system
bandwidth. While the LTE supports channel bandwidths up to 20 MHz,
the 5G NR supports channel bandwidths, for example, up to 500
MHz.
[0018] In order to effectively support multiple 5G services, such
as wideband services like eMBB and narrow-bandwidth services like
Internet of Things (IoT), it is preferable to multiplex these
services onto a single channel bandwidth. Further, if every 5G UE
needs to support transmission and reception in a transmission
bandwidth corresponding to the entire channel bandwidth, this may
hinder achievement of lower cost and lower power consumption of UEs
for narrow-bandwidth IoT services. Thus, the 3GPP allows one or
more bandwidth parts (BWPs) to be configured in the carrier
bandwidth (i.e., channel bandwidth or system bandwidth) of each NR
component carrier. Multiple BWPs in one NR channel bandwidth may be
used for different frequency division multiplexing (FDM) schemes
using different numerologies (e.g., subcarrier spacing (SCS)). The
bandwidth part is also referred to as carrier bandwidth part.
[0019] One bandwidth part (BWP) is frequency-consecutive and
consists of contiguous physical resource blocks (PRBs). The
bandwidth of one BWP is at least as large as a synchronization
signal (SS)/physical broadcast channel (PBCH) block. The BWP may or
may not include a SS/PBCH block (SSB). A BWP configuration
includes, for example, numerology, a frequency location, and a
bandwidth (e.g., the number of PRBs). In order to specify the
frequency location, common PRB indexing is used at least for a
downlink (DL) BWP configuration in a Radio Resource Control (RRC)
connected state. Specifically, an offset from PRB 0 to the lowest
PRB of the SSB to be accessed by a UE is configured by higher layer
signaling. The reference point "PRB 0" is common to all the UEs
that share the same wideband component carrier.
[0020] One SS/PBCH block includes primary signals necessary for an
idle UE, such as NR synchronization signals (NR-SS) and an NR
physical broadcast channel (NR-PBCH). The NR-SS is used by the UE
for DL synchronization. A Reference Signal (RS) is transmitted in
the SS/PBCH block to enable an idle UE to perform Radio Resource
Management (RRM) measurement (e.g., RSRP measurement). This RS may
be the NR-SS itself or may be an additional RS. The NR-PBCH
broadcasts part of the minimum System Information (SI), for example
a Master Information Block (MIB). The remaining minimum SI (RMSI)
is transmitted on a Physical Downlink Shared Channel (PDSCH).
[0021] A network can transmit multiple SS/PBCH blocks within the
channel bandwidth of one wideband component carrier. In other
words, SS/PBCH blocks may be transmitted in a plurality of BWPs
within the channel bandwidth. In a first scheme, all the SS/PBCH
blocks within one broadband carrier are based on NR-SS (e.g., a
primary SS (PSS) and a secondary SS (SSS)) corresponding to the
same physical-layer cell identity. In a second scheme, different
SS/PBCH blocks within one broadband carrier may be based on NR-SS
corresponding to different physical-layer cell identities.
[0022] From a UE perspective, a cell is associated with one SS/PBCH
block. Therefore, for UEs, each serving cell has a single
associated SS/PBCH block in frequency domain. Note that, each
serving cell is a primary cell (PCell) in carrier aggregation (CA)
and dual connectivity (DC), a primary secondary cell (PSCell) in
DC, or a secondary cell (SCell) in CA and DC. Such an SSB is
referred to as a cell defining SS/PBCH block. The Cell defining
SS/PBCH block has an associated RMSI. The Cell defining SS/PBCH
block is used as the time reference or the timing reference of the
serving cell. Further, the Cell defining SS/PBCH block is used for
SS/PBCH block (SSB) based RRM Measurements. The Cell defining
SS/PBCH block can be changed for the PCell/PSCell by "synchronous
reconfiguration" (e.g., reconfiguration of radio resource
configuration information using an RRC Reconfiguration procedure
and not involving a handover), while it can be changed for SCells
by "SCell release/add".
[0023] One or more BWP configurations for each component carrier
are semi-statically signaled to the UE. To be specific, for each
UE-specific serving cell, one or more DL BWPs and one or more UL
BWPs can be configured for the UE via a dedicated RRC message.
Further, each of the one or more BWPs configured for the UE can be
activated and deactivated. Activation/deactivation of a BWP is
determined not by an RRC layer but by a lower layer (e.g., Medium
Access Control (MAC) layer or Physical (PHY) layer). The activated
BWP is referred to as active BWP.
[0024] Switching of the active BWP may be performed, for example,
by Downlink Control Information (DCI) (e.g., scheduling DCI)
transmitted on a NR Physical Downlink Control Channel (PDCCH). In
other words, deactivation of the current active BWP and activation
of a new active BWP may be performed by the DCI in the NR PDCCH.
Thus, the network can activate/deactivate a BWP depending, for
example, on a data rate, or on numerology required by a service,
and can thereby dynamically switch the active BWP for the UE.
Activation/deactivation of the BWP may be performed by a MAC
Control Element (CE).
[0025] FIGS. 6 and 7 show usage examples of BWPs. In the example
shown in FIG. 6, the channel bandwidth of one component carrier is
divided into BWP #1 and BWP #2, and these two BWPs are used for FDM
schemes using different numerologies (e.g., different subcarrier
spacing). In the example shown in FIG. 7, narrowband BWP #1 is set
in a channel bandwidth of one component carrier and narrowband BWP
#2 narrower than BWP #1 is further set within the BWP #1. When BWP
#1 or BWP #2 is activated for the UE, this UE can reduce its power
consumption by refraining from performing reception and
transmission within the channel bandwidth except the active
BWP.
[0026] Non Patent Literatures 1 to 7 disclose the above-described
BWP and cell defining SS/PBCH block.
[0027] Further, the 3GPP discusses the requirements for Radio Link
Monitoring (RLM) related to the use of BWPs (see Non Patent
Literature 8). The RLM procedure is used by the UE in connected
mode (i.e., RRC_CONNECTED) in order to measure downlink radio
quality of the serving cell for the purpose of detecting out of
synchronization (out-of-sync) and detecting Radio Link Failure
(RLF).
[0028] Non Patent Literature 8 discloses the following matters. NR
supports RLM in the PCell and the PSCell only. One or more BWPs can
be configured per cell for a UE in connected mode semi-statically.
The UE can switch a specific BWP for the communication with the gNB
among the configured BWPs. This switching is carried out in shorter
time scale, such as several scheduling intervals. This specific BWP
is called the active BWP. The UE can only access one BWP at a time.
The active BWP has at least a Channel State Information Reference
Signal (CSI-RS) configured for RLM. A single RS type between CSI-RS
and SS/PBCH block is configured to be monitored for RLM at a time.
Even when different types of RS (i.e., CSI-RS and SS/PBCH block)
are simultaneously configured in one BWP, only single RS is chosen
for RLM and its related parameter is used for RLM. It is discussed
that, when the DL active BWP is switched (or changed), the UE keeps
on-going L3 parameters related to RLM. In this case, even when the
DL active BWP is switched, the UE does not reset L3 parameters
related to RLM to their default values.
[0029] Further, Non Patent Literature 9 discloses the following
matters as to the case where the SS/PBCH block (SSB) is monitored
for RRM measurements (i.e., SS/PBCH block (SSB) based RRM
Measurements). The (SSB-based) Intra-frequency Measurement is
defined as a measurement when the center frequency of the (cell
defining) SSB of the serving cell and the center frequency of the
(cell defining) SSB of the neighbor cell are the same and the
subcarrier spacings of the two SSBs are also the same. On the other
hand, the (SSB-based) inter-frequency measurement is defined as a
measurement when the center frequency of the (cell defining) SSB of
the serving cell and the center frequency of the (cell defining)
SSB of the neighbor cell are different, or the subcarrier spacings
of the two SSBs are different.
[0030] Further, the 3GPP discusses the necessity of measurement
gaps in radio frequency (RF) measurements (see Non Patent
Literature 10). Non Patent Literature 10 discloses that a UE
performs a measurement outside of its active BWP during a
measurement gap.
[0031] Note that, the 3GPP Release 14 and previous releases include
the following regulations related to measurement gaps for
inter-frequency measurements. According to the 3GPP Release 13 and
previous releases, in the case of CA and DC, measurements in
activated CCs are performed without measurement gaps. Whether or
not measurement gaps are needed for Inter-frequency measurements
and Inter-RAT measurements depends on UE capabilities (e.g.,
whether a UE has multiple receivers or not). UE capability
signaling is used to notify the eNodeB of the necessity of
measurement gaps for each supported and measured band.
[0032] Further, in the 3GPP Release 14, the eNB can configure
per-CC (or per-serving cell) measurement gaps for a UE. The
secondary cell (SCell) is activated or deactivated by a MAC Control
Element (CE). Note that, however, the PCell and the PSCell are not
changed by MAC CEs. In the situation where the PCell and the PSCell
are not changed, the UE can measure other CCs different from the
activated CC by using per-CC measurement gaps configured by a RRC
Connection reconfiguration.
CITATION LIST
Non Patent Literature
[0033] Non Patent Literature 1: 3GPP R1-1711795, Ericsson, "On
bandwidth parts and "RF" requirements", TSG RAN1 NR Ad-Hoc#2,
Qingdao, P.R. China, June 2017 [0034] Non Patent Literature 2: 3GPP
R2-1707624, "LS on Bandwidth Part Operation in NR", 3GPP TSG RAN
WG2#99, Berlin, Germany, August 2017 [0035] Non Patent Literature
3: 3GPP R2-1710012, "LS on Further agreements for Bandwidth part
operation", 3GPP TSG RAN WG2 #99bis, Prague, Czech Republic,
October 2017 [0036] Non Patent Literature 4: 3GPP R2-1710031,
"Reply LS on multiple SSBs within a wideband carrier", 3GPP TSG RAN
WG2 #99bis, Prague, Czech Republic, October 2017 [0037] Non Patent
Literature 5:3GPP R2-1711640, ZTE Corporation, Sane Chips, "Initial
discussion on the impacts of BWP on RAN2", 3GPP TSG-RAN WG2 Meeting
#99bis, Prague, Czech Republic, October 2017 [0038] Non Patent
Literature 6: 3GPP R2-1711969, Ericsson, "Text Proposal for L1
parametrs for 38.331", 3GPP TSG-RAN WG2 #99bis, Prague, Czech
Republic, October 2017 [0039] Non Patent Literature 7: 3GPP
R2-1709861, "LS on multiple SSBs within a wideband carrier", 3GPP
TSG RAN WG2#99, Berlin, Germany, August 2017 [0040] Non Patent
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part", 3GPP TSG RAN WG2 #99bis, Prague, Czech Republic, October
2017 [0041] Non Patent Literature 9: 3GPP R2-1710051, "LS on
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R2-1711187, Samsung, "Framework to support bandwidth parts in NR",
3GPP TSG RAN WG2 #99bis, Prague, Czech Republic, October 2017
SUMMARY OF INVENTION
Technical Problem
[0043] The present inventor has conducted studies on RF measurement
(e.g., RLM measurement and CSI measurement) when multiple BWPs are
configured within a single channel bandwidth and found several
problems. For example, consider a case where a UE in connected mode
(e.g., NR RRC_CONNECTED) monitors, for RLM measurement and CSI
measurement, another BWP belonging to the same component carrier
bandwidth (i.e., the channel bandwidth) as its active BWP. In this
case, whether or not a measurement gap is needed is considered to
be dependent on UE Capabilities. However, there is a problem that,
when one carrier bandwidth includes multiple BWPs, it is unclear
how the UE and the gNB configure a measurement gap for inter-BWP
measurement of those BWPs. One of the objects to be attained by
embodiments disclosed herein is to provide an apparatus, a method,
and a program that contribute to solving this problem. It should be
noted that this object is merely one of the objects to be attained
by the embodiments disclosed herein. Other objects or problems and
novel features will be made apparent from the following description
and the accompanying drawings.
Solution to Problem
[0044] In a first aspect, a radio terminal includes a memory and at
least one processor coupled to the memory. The at least one
processor is configured to transmit, to a radio access network
(RAN) node in a radio access network (RAN), an indication
indicating whether a measurement gap for inter-bandwidth part (BWP)
measurement among BWPs included in a plurality of downlink BWPs is
required. The downlink BWPs are included within one system
bandwidth. The at least one processor is further configured to
receive, from the RAN node, a measurement configuration including a
measurement gap configuration for one or more BWPs included in the
downlink BWPs.
[0045] In a second aspect, a radio access network (RAN) node
includes a memory and at least one processor coupled to the memory.
The at least one processor is configured to receive, from a radio
terminal, an indication indicating whether a measurement gap for
inter-bandwidth part (BWP) measurement among BWPs included in a
plurality of downlink BWPs is required. The downlink BWPs are
included within one system bandwidth. The at least one processor is
further configured to transmit, to the radio terminal, a
measurement configuration including a measurement gap configuration
for one or more BWPs included in the downlink BWPs.
[0046] In a third aspect, a method for a radio terminal includes:
transmitting, to a radio access network (RAN) node in a radio
access network (RAN), an indication indicating whether a
measurement gap for inter-bandwidth part (BWP) measurement among
BWPs included in a plurality of downlink BWPs is required, the
downlink BWPs being included within one system bandwidth; and
receiving, from the RAN node, a measurement configuration including
a measurement gap configuration for one or more BWPs included in
the downlink BWPs.
[0047] In a fourth aspect, a method for a radio access network
(RAN) node includes: receiving, from a radio terminal, an
indication indicating whether a measurement gap for inter-bandwidth
part (BWP) measurement among BWPs included in a plurality of
downlink BWPs is required, the downlink BWPs being included within
one system bandwidth; and transmitting, to the radio terminal, a
measurement configuration including a measurement gap configuration
for one or more BWPs included in the downlink BWPs.
[0048] In a fifth aspect, a program includes instructions (software
codes) that, when loaded into a computer, cause the computer to
perform the method according to the above-described third or fourth
aspect.
Advantageous Effects of Invention
[0049] According to the above-deceived aspects, it is possible to
provide an apparatus, a method, and a program that allow a radio
terminal to be configured with a proper measurement gap for
inter-BWP measurement within one carrier bandwidth.
BRIEF DESCRIPTION OF DRAWINGS
[0050] FIG. 1 is a diagram showing a basic architecture of a 5G
System;
[0051] FIG. 2 is a diagram showing a network configuration of
EN-DC;
[0052] FIG. 3 is a diagram showing a network configuration of
NE-DC;
[0053] FIG. 4 is a diagram showing a network configuration of
NG-EN-DC;
[0054] FIG. 5 is a diagram showing a network configuration of NR-NR
DC;
[0055] FIG. 6 is a diagram showing an example of use of Bandwidth
parts (BWPs);
[0056] FIG. 7 is a diagram showing an example of use of Bandwidth
parts (BWPs);
[0057] FIG. 8 is a diagram showing a configuration example of BWPs
and SS/PBCH blocks;
[0058] FIG. 9 is a diagram showing a configuration example of BWPs
and SS/PBCH blocks;
[0059] FIG. 10 is a diagram showing a configuration example of a
radio communication network according to several embodiments;
[0060] FIG. 11 is a flowchart showing an example of an operation of
a radio terminal according to a first embodiment;
[0061] FIG. 12 is a flowchart showing an example of an operation of
a RAN node according to the first embodiment;
[0062] FIG. 13A is a diagram showing an example of use of Bandwidth
parts (BWPs);
[0063] FIG. 13B is a diagram showing an example of use of Bandwidth
parts (BWPs);
[0064] FIG. 13C is a diagram showing an example of use of Bandwidth
parts (BWPs);
[0065] FIG. 14A is a diagram showing an example of signaling
indicating necessity of measurement gaps;
[0066] FIG. 14B is a diagram showing an example of signaling
indicating necessity of measurement gaps;
[0067] FIG. 14C is a diagram showing an example of signaling
indicating necessity of measurement gaps;
[0068] FIG. 15A is a diagram showing an example of signaling
indicating necessity of measurement gaps;
[0069] FIG. 15B is a diagram showing an example of signaling
indicating necessity of measurement gaps;
[0070] FIG. 15C is a diagram showing an example of signaling
indicating necessity of measurement gaps;
[0071] FIG. 16 is a sequence diagram showing an example of
operations of a radio terminal and a RAN node according to a second
embodiment;
[0072] FIG. 17 is a sequence diagram showing an example of
operations of a radio terminal and a RAN node according to a third
embodiment;
[0073] FIG. 18 is a sequence diagram showing an example of
operations of a radio terminal and a RAN node according to a fourth
embodiment;
[0074] FIG. 19 is a block diagram showing a configuration example
of a RAN node according to some embodiments; and
[0075] FIG. 20 is a block diagram showing a configuration example
of a radio terminal according to some embodiments.
DESCRIPTION OF EMBODIMENTS
[0076] Specific embodiments will be described hereinafter in detail
with reference to the drawings. The same or corresponding elements
are denoted by the same symbols throughout the drawings, and
duplicated explanations are omitted as necessary for the sake of
clarity.
[0077] Each of the embodiments described below may be used
individually, or two or more of the embodiments may be
appropriately combined with one another. These embodiments include
novel features different from each other. Accordingly, these
embodiments contribute to attaining objects or solving problems
different from one another and also contribute to obtaining
advantages different from one another.
[0078] The following descriptions on the embodiments mainly focus
on the 3GPP 5G systems. However, these embodiments may be applied
to other radio communication systems.
[0079] First, the definition of terms used in cases where one
system bandwidth includes multiple BWPs is described with reference
to FIGS. 8 and 9. FIGS. 8 and 9 show configuration examples of BWPs
and SS/PBCH blocks. In the examples shown in FIGS. 8 and 9, one
channel bandwidth includes three BWPs: BWP #1, BWP #2 and BWP #3.
BWP #1 and BWP #2 include SS/PBCH block (SSB) #1 and SSB #2,
respectively, while BWP #3 does not include any SS/PBCH blocks.
[0080] From a network perspective, the entire bandwidth (i.e.,
channel bandwidth or system bandwidth) of one component carrier
corresponds to one cell, just like in the existing LTE. In the
examples of FIGS. 8 and 9, Physical Cell Identity (PCI) associated
with a cell corresponding to the channel bandwidth is "PCIx".
[0081] In this specification, a cell from the network perspective
is defined as a "logical cell." Further, a PCI associated with the
cell from the network perspective (i.e., logical cell) is defined
as a reference PCI. Note that, the cell from the network
perspective (i.e., logical cell) may be associated with one Cell
Identity. In this case, the Cell Identity of the cell from the
network perspective (i.e., logical cell) may be associated with
(sub-)PCIs of a plurality of physical cells, which are described
later.
[0082] On the other hand, as described earlier, from a UE
perspective, a cell is associated with one SS/PBCH block. In this
specification, a cell from the UE perspective is defined as a
"physical cell." Further, a PCI associated with the cell from the
UE perspective (i.e., physical cell) is defined as a sub-PCI.
Specifically, multiple BWPs that are included in the same system
bandwidth and include their respective SS/PBCH blocks are multiple
cells from the UE perspective (i.e., multiple physical cells).
Sub-PCIs of these cells from the UE perspective (i.e., physical
cells) are associated with one reference PCI or one Cell Identity
of the cell from the network perspective (i.e., logical cell).
Further, a BWP not including any SS/PBCH blocks may be defined as a
cell from the UE perspective (i.e., physical cell), or a group of
BWPs including a BWP without SS/PBCH block and a BWP with SS/PBCH
block, which is referred to by the former one, may be defined as a
cell from the UE perspective (i.e., physical cell). Note that, also
in the network perspective, a unit system bandwidth that is
actually used by the network (e.g., RAN node) for communication
with the UE is each cell from the UE perspective (i.e., physical
cell).
[0083] In the example of FIG. 8, the three BWPs support the same
numerology (i.e., numerology #1), and all the SS/PBCH blocks (i.e.,
SSB #1 and SSB #2) within the channel bandwidth are based on NR-SS
corresponding to the same (sub-)PCI (i.e., PCIx). Thus, FIG. 8
corresponds to the first scheme, which is described above in
relation to transmission of multiple SS/PBCH blocks in one channel
bandwidth. To synchronize with BWP #3 not including any SSBs, the
UE monitors one of SSB #1 and SSB #2 transmitted in other BWPs. SSB
#1 or SSB #2 to be monitored is referred to as a reference SSB, and
the UE may receive a notification of the identifier of the
reference SSB (SSB index, e.g., SSB #1 or #2) from the network.
[0084] In the example of FIG. 9, BWP #1 supports numerology #1,
while BWP #2 and BWP #3 support numerology #2. Different SSBs #1
and #2 with different numerologies are based on NR-SSs
corresponding to different (sub-)PCIs (i.e., PCIx and PCIy). Thus,
FIG. 9 corresponds to the second scheme, which is described above
in relation to transmission of multiple SS/PBCH blocks in one
channel bandwidth. To synchronize with BWP #3 not including any
SSBs, the UE monitors, for example, SSB #2 of BWP #2 that supports
the same numerology as BWP #3. Alternatively, to synchronize with
BWP #3 not including any SSBs, the UE may monitor SSB #1 of BWP #1
that supports numerology different from that of BWP #3.
[0085] In the example of FIG. 8, sub-PCIs (i.e., PCIx and PCIx) of
two cells from the UE perspective (i.e., physical cells) are
associated with the reference PCI (i.e., PCIx) or Cell Identity of
one cell from the network perspective (i.e., logical cell).
Meanwhile, in the example of FIG. 9, sub-PCIs (i.e., PCIx and PCIy)
of two cells from the UE perspective (i.e., physical cells) are
associated with the reference PCI (i.e., PCIx) or Cell Identity of
one cell from the network perspective (i.e., logical cell).
[0086] The network (e.g., RAN node) may configure the UE with a BWP
set including one or more BWPs. In other words, the UE receives,
from the network, configuration information of one or more BWPs
(e.g., SSB indexes, presence of SSBs, reference SSB indexes,
Layer-1 parameters). The BWP set may be configured individually for
each of downlink (DL) and uplink (UL). Thus, the BWP set may
include a DL BWP set for DL and an UL BWP set for UL.
Alternatively, an UL BWP and a DL BWP may be associated in advance
with each other, and in this case the BWP set may be common to DL
and UL. The UE can activate k (k<=K) BWPs among K BWPs included
in the (DL/UL) BWP set. Stated differently, for certain UE, up to K
(DL/UL) BWP(s) can be activated at a time. In the following
description, it is assumed for the sake of simplification that one
BWP (i.e. k=1) is activated. Note that, however, this embodiment
and the subsequent embodiments are applicable also to the cases
where two or more (k>=2) BWPs are activated at a time.
[0087] Further, in this specification, the term "BWP group" is
employed. A BWP group is contained in a BWP set. One BWP group
consists of one or more BWPs among which the active BWP can be
changed by DCI transmitted on a NR PDCCH. Among one or more BWPs
included in the same BWP group, the active BWP can be changed
without change of the Cell defining SSB. Thus, the BWP group may be
defined as one or more BWPs associated with the same cell defining
SSB. One BWP group may include one BWP including the cell defining
SSB (e.g., base BWP, initial BWP, or default BWP) and one or more
other BWPs. Each of one or more other BWPs, which are not the base
BWP (or initial BWP, default BWP), may or may not include a SSB.
The UE may be explicitly informed (or may be configured as to)
which SSB is the cell defining SSB. Alternatively, the UE may
implicitly consider that the cell defining SSB is the SSB of the
initial BWP when the UE has been configured with the BWP group.
[0088] The BWP group may be configured individually for each of
downlink (DL) and uplink (UL). Thus, the BWP group may include a DL
BWP group for DL and an UL BWP group for UL. Alternatively, an UL
BWP and a DL BWP may be associated in advance with each other, and
the BWP group in this case may be common to DL and UL.
[0089] In the example of FIG. 8, the UE is configured with one BWP
set including BWP #1 to #3. In the example of FIG. 8, the UE may
monitor SSB #1 transmitted in BWP #1 to synchronize with BWP #3
(i.e., to achieve synchronization in BWP #3). In this case, BWP #1
and BWP #3 may correspond to one BWP group, while BWP #2 may
correspond to another one BWP group. Thus, one BWP set (BWPs #1,
#2, and #3) may include a first BWP group (BWPs #1 and #3) and a
second BWP group (BWP #2). Alternatively, one BWP set (BWPs #1, #2,
and #3) may include a first BWP group (BWP #1) and a second BWP
group (BWPs #2 and #3). Further alternatively, one BWP set (BWPs
#1, #2, and #3) may correspond to one BWP group (BWPs #1, #2, and
#3). In this case, one of SSB #1 and SSB #2 serves as the cell
defining SSB for the UE.
[0090] In the example of FIG. 9 also, the UE is configured with one
BWP set including BWP #1 to #3. In one example, BWP #1 with
numerology #1 may correspond to one BWP group, while BWP #2 and BWP
#3 with numerology #2 may correspond to another one BWP group.
Thus, one BWP set (BWPs #1, #2, and #3) may include a first BWP
group (BWP #1) and a second BWP group (BWPs #2 and #3). Note that,
as described earlier, BWPs with different numerologies may be
included in one BWP group. Thus, in another example, one BWP set
(BWPs #1, #2, and #3) may include a first BWP group (BWPs #1 and
#3) and a second BWP group (BWP #2). Further alternatively, one BWP
set (BWPs #1, #2, and #3) may correspond to one BWP group (BWPs #1,
#2, and #3). In this case, one of SSB #1 and SSB #2 serves as the
cell defining SSB for the UE.
[0091] As described earlier, activation/deactivation of a BWP may
be performed by a lower layer (e.g., Medium Access Control (MAC)
layer, or Physical (PHY) layer), rather than by the RRC layer. A
timer (e.g., BWP Inactivity Timer in the MAC layer) may be used for
activation/deactivation of a DL BWP. The UE may switch the active
BWP according to a timer based on a set value provided by the gNB.
This timer may represent a period or duration in the unit of
subframes. For example, when the UE transmit or receive no data for
a predetermined period (i.e., expiration of the timer value) in the
active BWP, it switches the active BWP to a predetermined BWP
(e.g., default BWP, or BWP including the cell defining SSB). Such
determination of the change of the active BWP based on the timer
may be made also in the network (e.g., RAN node).
First Embodiment
[0092] FIG. 10 shows a configuration example of a radio
communication network according to several embodiments including
this embodiment. In the example of FIG. 10, the radio communication
network includes a RAN node 11 and a radio terminal (UE) 12. The
RAN node 11 is, for example, a gNB, or an eNB in MR-DC. The RAN
node 11 may be a Central Unit (CU) (e.g., gNB-CU) or a Distributed
Unit (DU) (e.g., gNB-DU) in the cloud RAN (C-RAN) deployment. The
Central Unit (CU) is also referred to as a Baseband Unit (BBU) or a
digital unit (DU). The Distributed Unit (DU) is also referred to as
a Radio Unit (RU), a Remote Radio Head (RRH), a Remote Radio
Equipment (RRE), or a Transmission and Reception Point (TRP or
TRxP).
[0093] The UE 12 is connected to the RAN node 11 through an air
interface 1001. The UE 12 may be simultaneously connected to a
plurality of RAN nodes for dual connectivity. The UE 12 in
connected mode can be semi-statically configured with one or more
BWPs per cell. The UE 12 can switch its active BWP, used for
communication with the RAN node 11 (e.g., MgNB) or another RAN node
(e.g., SgNB), among the configured BWPs. This switching is done in
a short time, e.g., several scheduling intervals.
[0094] The UE 12 performs an RLM procedure when it is in connected
mode (e.g., NR RRC_CONNECTED). The UE 12 performs RLM measurement
in the RLM procedure. Specifically, the UE 12 measures downlink
radio quality of the serving cell for the purpose of detecting out
of synchronization (out-of-sync) and detecting Radio Link Failure
(RLF). The UE 12 may be simultaneously connected to a plurality of
RAN nodes for dual connectivity. In this case, the UE 12 may
perform RLM in the PCell and RLM in the PS Cell simultaneously.
[0095] Further, the UE 12 may perform CSI measurement when it is in
connected mode (e.g., NR RRC_CONNECTED). The CSI measurement
includes, when the UE 12 is in connected mode (e.g., NR
RRC_CONNECTED), measuring the DL radio quality of the serving cell
for the purpose of transmitting to the RAN node 11 a report
including Channel Quality Indicator (CQI) to be used for one or
both of scheduling and link adaptation. The UE 12 may be
simultaneously connected to a plurality of RAN nodes for dual
connectivity. In this case, the UE 12 may simultaneously perform
CSI measurement in the MCG and CSI measurement in the SCG.
[0096] Furthermore, the UE 12 may perform RRM measurement when it
is in connected mode (e.g., NR RRC_CONNECTED). For example, in the
RRM measurement in connected mode, the UE 12 measures the RSRP and
RSRQ of the serving cell and those of the neighbor cell, and
transmits to the RAN node 11 an RRM reporting event for triggering
a handover.
[0097] Each BWP has at least CSI-RS that can be used for RLM
measurement, RRM measurement and CSI measurement. The active BWP
may or may not contain an SS/PBCH block (SSB). Either type, i.e.,
CSI-RS or SS/PBCH block, is configured to be monitored for RLM at a
time. Even when different types of RS (i.e., CSI-RS and SS/PBCH
block) are simultaneously configured in one BWP, only one RS is
selected for RLM, and accordingly parameters related to the
selected RS are used for RLM.
[0098] The RAN node 11 provides a measurement configuration to the
UE 12. This measurement configuration relates to RF measurement to
be performed by the UE 12. The RF measurement includes at least one
of RLM measurement, CSI measurement and RRM measurement. Thus, this
measurement configuration includes at least one of an RLM
measurement configuration, a CSI measurement configuration and an
RRM measurement configuration.
[0099] The RLM measurement configuration may be referred to as an
RLF-related configuration. The RLM measurement configuration
includes, for example, parameters for RLM. The parameters for RLM
include, for example, a specified number of out-of-sync, a
specified number of in-sync, and an expiration period (or the
maximum time) of an RLF timer. The specified number of out-of-sync
is the number of consecutive "out-of-sync" indications received
from lower layers before the UE starts the radio link self-recovery
process. The specified number of in-sync is the number of
consecutive "in-sync" indications received from lower layers before
the UE determines that the radio link has recovered. The RLF timer
is used to determine (or detect) RLF. The UE starts the RLF timer
upon receiving the specified number of consecutive out-of-sync
indications, and stops the RLF timer upon receiving the specified
number of consecutive in-sync indications. The expiration period
(or the maximum time) of the RLF timer is equivalent to the maximum
time allowed for the recovery of the radio link which is performed
dynamically by the UE. The UE detects RLF upon expiry of the RLF
timer.
[0100] The CSI measurement configuration indicates, for example, a
sub-frame set where CSI measurement is to be performed.
[0101] The RRM measurement configuration includes, for example, an
RRM reporting configuration (ReportConfig). The RRM reporting
configuration indicates parameters (e.g., threshold, or offset, or
both) to be used for determination on each of one or more RRM
reporting events. As one example, the RRM reporting event related
to BWPs may indicate that a BWP in a neighbor cell becomes amount
of offset better than the active BWP in the serving cell
(PCell/PSCell). The RRM reporting event related to BWPs may be
defined by modifying the existing reporting events (e.g., events A1
to A6, C1 and C2) related to handover, CA and DC.
[0102] For example, the RRM reporting events related to BWPs may be
defined by replacing the term"Serving" in the existing reporting
events with "active BWP" (or "default BWP"). Further, the RRM
reporting events related to BWPs may be defined by replacing the
term "Neighbour" in the existing reporting events with "BWP"
(configured in MeasObject). The RRM reporting events related to
BWPs may include the following: [0103] Event D1: Serving BWP
becomes better than absolute threshold; [0104] Event D2: Serving
BWP becomes worse than absolute threshold; [0105] Event D3:
Neighbour BWP becomes amount of offset better than Primary BWP (or
default BWP); [0106] Event D4: Neighbour BWP becomes better than
absolute threshold; [0107] Event D5: Primary BWP (or default BWP)
becomes worse than absolute threshold 1 AND Neighbour BWP becomes
better than another absolute threshold 2; [0108] Event D6:
Neighbour BWP becomes amount of offset better than Secondary
BWP.
[0109] Note that, a cell list (e.g., cellToAddModList) for
measurement indicated in MeasObject includes identifiers of cells
to be measured (e.g., Cell Index, or PCI). However, a BWP not
including any SSBs does not have its specific (sub-)PCI. Therefore,
instead of measurement for the BWP not including any SSBs,
measurement for the cell defining SSB may be performed.
Alternatively, in order to indicate the BWP not including any SSBs,
the PCI of the BWP including the cell defining SSB associated
therewith (i.e., the PCI designated by the cell defining SSB), or a
virtual PCI may be assigned to it. Alternatively, a BWP index may
be used as an alternative (or substitute) identifier.
[0110] The UE 12 can be configured by the RAN node 11 with one or
more DL BWPs included in one component carrier bandwidth (i.e.,
system bandwidth or channel bandwidth). The UE 12 handles inter-BWP
measurement within the system bandwidth as inter-frequency
measurement. This measurement may be RLM measurement or RRM
measurement within the BWP set (or the BWP group) corresponding to
the serving cell from the UE perspective (i.e., physical cell)
configured in the UE 12. In addition, or alternatively, this
measurement may be RRM measurement between any BWPs in the BWP set
corresponding to the serving cell from the UE perspective (physical
cell) configured in the UE 12 and a BWP(s) outside the BWP set
(i.e., BWP(s) corresponding to a neighbor cell (physical cell)
within the system bandwidth). Note that, the configuration for
measuring a BWP(s) outside the BWP set at least includes
information needed for measurement (e.g., RRM measurement), and it
does not necessarily include normal BWP-related information (e.g. a
configuration information about a BWP needed for the UE to camp on
this BWP). The term "measurement BWP set" may be defined to
collectively refer to those BWPs (and BWP sets).
[0111] FIG. 11 is a flowchart showing a process 1100 that is an
example of an operation performed by the UE 12. In Step 1101, the
UE 12 transmits, to the RAN node 11, indication indicating whether
a measurement gap is required or not. This indication indicates
whether a measurement gap is required for inter-BWP measurement
among BWPs included in multiple DL BWPs (i.e., DL BWPs with
different frequencies or different numerologies or both). In Step
1102, the UE 12 receives, from the RAN node 11, a measurement
configuration (e.g., an RRM measurement configuration) including a
measurement gap configuration for measurement of one or more BWPs
included in these DL BWPs.
[0112] The measurement gap is a time period in which UE uplink and
downlink transmission is not scheduled, and accordingly the UE can
perform measurements. In other words, the measurement gap defines a
period which the UE is allowed to use for measurements.
[0113] FIG. 12 is a flowchart showing a process 1200 that is an
example of an operation performed by the RAN node 11. In Step 1201,
the RAN node 11 receives, from the UE 12, indication indicating
whether a measurement gap for inter-BWP measurement among BWPs
included in multiple DL BWPs is required. In Step 1202, the RAN
node 11 transmits, to the UE 12, a measurement configuration
including a measurement gap configuration for measurement of one or
more BWPs included in these DL BWPs.
[0114] In some implementations, the indication indicating whether a
measurement gap for inter-BWP measurement is required may indicate
whether the UE 12 needs a measurement gap for measurement of one or
more BWPs that are included in the DL BWPs but are different from
the BWP to be activated for the UE 12. The BWP to be activated for
the UE 12 is the BWP corresponding to the serving cell (physical
cell). In other words, this indication may indicate whether, when
one BWP is activated for the UE 12, the UE 12 needs a measurement
gap for measurement of other BWPs different from this active BWP.
For example, this indication may indicate that, when BWP #1 is
activated for the UE 12, a measurement gap is required for
measurement of at least one of BWP #2 and BWP #3. BWP #1, BWP #2
and BWP #3 are included in the same component carrier bandwidth
(i.e., system bandwidth or channel bandwidth).
[0115] In some implementations, the indication indicating whether a
measurement gap for inter-BWP measurement is required may indicate,
per BWP, whether the UE 12 needs a measurement gap for one or more
BWPs that are included in the multiple DL BWPs but are different
from the BWP to be activated for the UE 12. In other words, this
indication may indicate whether the UE 12 needs a measurement gap
for measurement of a specific BWP(s) included in the multiple DL
BWPs but different from the BWP to be activated for the UE 12. For
example, this indication may indicate that, when BWP #1 is
activated for the UE 12, a measurement gap is needed for
measurement of BWP #2 while a measurement gap is not needed for
measurement of BWP #3.
[0116] In some implementations, the indication indicating whether a
measurement gap for inter-BWP measurement is required may include
information regarding all BWP pairs included in the multiple DL
BWPs (or a specific BWP pair indicated by the RAN node). To be more
specific, this indication may indicate whether, when one BWP of
each BWP pair is activated for the UE 12, the UE 12 needs a
measurement gap for measurement of the other BWP of each BWP pair.
Further, this method may be applied to a combination of three or
more BWPs (BWP combination (BwC)) included in the multiple DL BWPs.
For example, this indication may indicate whether, when one BWP of
each BWP combination is activated for the UE 12, the UE 12 needs
measurement gaps for measurement of each remaining BWPs of this BWP
combination.
[0117] The measurement gap configuration, which is transmitted from
the RAN node 11 to the UE 12, indicates the configuration regarding
a measurement gap to be used by the UE 12 to measure one or more
BWPs different from the activated BWP when one of the multiple DL
BWPs is activated for the UE 12. The measurement gap configuration
indicates, for example, at least one of: the presence or absence of
a measurement gap; the length of a measurement gap; and the pattern
of a measurement gap. For example, this measurement gap
configuration may indicate the presence or absence of a measurement
gap when BWP #1 is activated for the UE 12. When a measurement gap
for BWP #1 is configured, the UE 12 may perform measurement of one
or both of BWP #2 and BWP #3 in this measurement gap.
[0118] The UE 12 may determine the indication, which indicates
whether a measurement gap for inter-BWP measurement is required,
depending on the RF receiver configuration of the UE 12 and the
number of BWPs configured simultaneously (in other words, the
number of BWPs included in the configured BWP group). To be
specific, to generate this indication, the UE 12 may take into
account the number of RF receivers in the UE 12. The RF receivers
are also referred to as RF chains.
[0119] The following provides examples of the indication indicating
need or no need of a measurement gap for inter-BWP measurement,
which is transmitted from the UE 12 to the RAN node 11, with
reference to FIGS. 13A to 13C, FIGS. 14A to 14C, and FIGS. 15A to
15C. Consider as an example the case where the UE 12 is equipped
with two RF chains (i.e., RF chain #1 and RF chain #2). Further, it
is assumed in this example that the bandwidth that can be covered
by each RF chain of the UE 12 (which is also referred to as RF
bandwidth) is larger than the bandwidth of one BWP but smaller than
the total bandwidth of two BWPs. Accordingly, in the case of
measuring multiple BWPs with one RF chain, the UE 12 needs to
sequentially receive signals in each of these BWPs, while changing
the RF (frequency) of this RF chain as appropriate.
[0120] FIGS. 13A to 13C show three examples of one or more BWPs
(i.e. a BWP set) configured in one component carrier bandwidth. In
the example of FIG. 13A, three BWP groups are configured in one
component carrier bandwidth (i.e., channel bandwidth or system
bandwidth). Each BWP group consists of one BWP. Specifically, BWP
#1, BWP #2, and BWP #3 shown in FIG. 13A include SSB #1, SSB #2,
and SSB #3, respectively. According to the definition of the terms
in this specification, one cell from the network perspective (i.e.,
logical cell) includes three cells from the UE perspective (i.e.,
physical cells) in the example of FIG. 13A. Switching of the active
BWP among those three BWPs (i.e., among three physical cells)
corresponds to switching of the active BWP among BWP groups (i.e.,
among physical cells), which is accordingly performed by RRC
signaling (e.g., a RRC Reconfiguration message). For example, the
UE 12 receives signals sequentially in BWP #1 and BWP #2 with RF
chain #1, while it receives signals in BWP #3 with RF chain #2.
[0121] In the example of FIG. 13B, two BWP groups are configured in
one component carrier bandwidth (i.e., channel bandwidth or system
bandwidth). One of the two BWP groups includes BWP #1 and BWP #2,
while the other one includes BWP #3. BWP #1 and BWP #2 are
associated with (cell defining) SSB #1 in BWP #1. BWP #3 is
associated with (cell defining) SSB #3 in BWP #3. According to the
definition of the terms in this specification, one logical cell
includes two physical cells in the example of FIG. 13B. Switching
of the active BWP between BWP #1 and BWP #2 corresponds to
switching of the active BWP within one BWP group (i.e., one
physical cell), which is accordingly performed by PDCCH/DCI (i.e.,
DCI transmitted on a NR PDCCH). On the other hand, switching of the
active BWP between BWP #1 and BWP #3 and between BWP #2 and BWP #3
corresponds to switching of the active BWP between BWP groups
(i.e., between physical cells), which is accordingly performed by
RRC signaling (e.g., a RRC Reconfiguration message). For example,
the UE 12 receives signals sequentially in BWP #1 and BWP #2 with
RF chain #1, while it receives signals in BWP #3 with RF chain
#2.
[0122] In the example of FIG. 13C, one BWP group is configured in
one component carrier bandwidth (i.e., channel bandwidth or system
bandwidth). This BWP group includes BWP #1, BWP #2 and BWP #3.
Those three BWPs are associated with (cell defining) SSB #1 in BWP
#1. According to the definition of the terms in this specification,
one logical cell includes one physical cell in the example of FIG.
13C. Switching of the active BWP among these three BWPs (i.e.,
three physical cells) corresponds to switching of the active BWP
within one BWP group (i.e., one physical cell), which is
accordingly performed by PDCCH/DCI. For example, the UE 12 receives
signals in BWP #1 with RF chain #1, while it receives signals
sequentially in BWP #2 and BWP #3 with RF chain #2.
[0123] FIGS. 14A to 14C show one example of the indication of need
or no need of measurement gaps by the UE 12. In the example of
FIGS. 14A to 14C, the UE 12 notifies the RAN node 11 of whether the
UE 12 needs a measurement gap for inter-BWP measurement of one or
more BWPs that are included in the three DL BWPs but are different
from the BWP to be activated for the UE 12.
[0124] FIG. 14A is related to the BWP configuration of FIG. 13A.
When the active BWP is BWP #1, the UE 12 transmits, to the RAN node
11, the indication indicating that it needs a measurement gaps for
measurement of BWP #2 while it does not need a measurement gap for
measurement of BWP #3. When the active BWP is BWP #2, the UE 12
transmits, to the RAN node 11, the indication indicating that it
needs a measurement gap for measurement of BWP #1 while it does not
need a measurement gap for measurement of BWP #3. When the active
BWP is BWP #3, the UE 12 transmits, to the RAN node 11, the
indication indicating that it needs no measurement gaps for
measurement of BWP #1 and BWP #2.
[0125] FIG. 14B is related to the BWP configuration of FIG. 13B. In
the case of FIG. 14B, the UE 12 transmits, to the RAN node 11, the
indication about need or no need of measurement gaps which is the
same as that in the case of FIG. 14A.
[0126] FIG. 14C is related to the BWP configuration of FIG. 13C.
When the active BWP is BWP #1, the UE 12 transmits, to the RAN node
11, the indication indicating that it needs no measurement gaps for
measurement of BWP #2 and BWP #3. When the active BWP is BWP #2,
the UE 12 transmits, to the RAN node 11, the indication indicating
that it needs a measurement gap for measurement of BWP #3 while it
does not need a measurement gap for measurement of BWP #1. When the
active BWP is BWP #3, the UE 12 transmits, to the RAN node 11, the
indication indicating that it needs a measurement gaps for
measurement of BWP #2 while it does not need a measurement gap for
measurement of BWP #1.
[0127] FIGS. 15A to 15C show another example of the indication of
need or no need of measurement gaps by the UE 12. In the example of
FIGS. 15A to 15C, the UE 12 sends, to the RAN node 11, information
about three different BWP pairs included in the three DL BWPs. To
be more specific, the UE 12 notifies the RAN node 11 of whether,
when one BWP of each BWP pair is activated for the UE 12, the UE 12
needs a measurement gap for measurement of the other BWP of this
BWP pair.
[0128] FIG. 15A is related to the BWP configuration of FIG. 13A.
The UE 12 transmits, to the RAN node 11, the indication indicating
that a measurement gap is needed for the pair of BWP #1 and BWP #2.
This indication means that, when one of BWP #1 and BWP #2 (e.g.,
BWP #1) is the active BWP, a measurement gap is needed for
measurement of the other BWP (e.g., BWP #2). The UE 12 transmits,
to the RAN node 11, the indication indicating that a measurement
gap is not needed for the pair of BWP #1 and BWP #3. This
indication means that, when one of BWP #1 and BWP #3 (e.g., BWP #1)
is the active BWP, no measurement gap is needed for measurement of
the other BWP (e.g., BWP #3). Likewise, the UE 12 transmits, to the
RAN node 11, indication indicating that a measurement gap is not
needed for the pair of BWP #2 and BWP #3.
[0129] FIG. 15B is related to the BWP configuration of FIG. 13B. In
the case of FIG. 15B, the UE 12 transmits, to the RAN node 11,
indication about need or no need of measurement gaps which is the
same as that in the case of FIG. 15A.
[0130] FIG. 15C is related to the BWP configuration of FIG. 13C.
The UE 12 transmits, to the RAN node 11, the indication indicating
that no measurement gap is needed for the pair of BWP #1 and BWP
#2. Likewise, the UE 12 transmits, to the RAN node 11, the
indication indicating that no measurement gap is needed for the
pair of BWP #1 and BWP #3. Meanwhile, the UE 12 transmits, to the
RAN node 11, the indication indicating that a measurement gap is
needed for the pair of BWP #2 and BWP #3.
[0131] The RAN node 11 may transmit, to the UE 12, a measurement
gap configuration that is determined in consideration of the
necessity of measurement gaps in the UE 12. To be specific, for
example, in response to receiving the information shown in FIG. 14A
from the UE 12, the RAN node 11 may configure the UE 12 with a
measurement gap to be used for measurement between BWP #1 and BWP
#2 when the BWP #1 is the active BWP. Alternatively, the RAN node
11 may operate so as to configure the UE 12 with no measurement gap
for measurement between BWP #1 and BWP #2 when the BWP #1 is the
active BWP.
[0132] The above-described description with reference to FIGS. 13A
to 13C, FIGS. 14A to 14C, and FIGS. 15A to 15C refers to the case
where the UE 12 is equipped with two RF chains and one system
bandwidth includes three BWPs as an example for the sake of
simplification. However, the above-described description is
applicable also to the case where the UE 12 is equipped with only
one RF chain, the case where the UE 12 is equipped with at least
three RF chains, the case where one system bandwidth includes two
BWPs, and the case where one system bandwidth includes at least
four BWPs as a matter of course.
[0133] As can be understood from the above description, the RAN
node 11 and the UE 12 operate as follows when one carrier bandwidth
includes multiple BWPs. The UE 12 transmits, to the RAN node 11, an
indication indicating whether a measurement gap is required for
inter-BWP measurement among BWPs included in multiple DL BWPs
within one carrier bandwidth. Further, the UE 12 receives, from the
RAN node 11, a measurement configuration including a measurement
gap configuration for one or more BWPs included in these multiple
DL BWPs. Meanwhile, the RAN node 11 receives from the UE 12 the
indication regarding need or no need of a measurement gap, and
transmits to the UE 12 the measurement configuration including the
measurement gap configuration. Thus, the RAN node 11 can be aware
of whether or not the UE 12 needs a measurement gap for measurement
between multiple DL BWPs within one carrier bandwidth. Further, the
RAN node 11 can transmit, to the UE 12, the measurement gap
configuration that is determined in consideration of the necessity
of measurement gaps in the UE 12. Thus, the RAN node 11 and the UE
12 allow the UE 12 to be configured with a proper measurement gap
for measurement between multiple DL BWPs within one carrier
bandwidth.
Second Embodiment
[0134] This embodiment provides a specific example of the sequence
(or procedure) in which the UE 12 transmits, to the RAN node 11,
the indication indicating, per BWP, whether the UE 12 needs a
measurement gap or not, which is described in the first embodiment.
A configuration example of a radio communication network according
to this embodiment is similar to that shown in FIG. 10.
[0135] FIG. 16 is a sequence diagram showing a process 1600 that is
an example of operations of the RAN node 11 and the UE 12 according
to this embodiment. In Step 1601, the UE 12 transmits UE NR radio
capability information to the RAN node 11 (e.g., gNB). The UE NR
radio capability information includes information indicating that a
measurement gap is needed for inter-frequency (inter-BWP)
measurement and information indicating that the UE 12 supports
indication of need or no need of a measurement gap per-BWP (per-BWP
Gap Indication). The UE NR radio capability information may be
transmitted using a UE Capability Information message.
[0136] In Step 1602, the RAN node 11 transmits, to the UE 12, a BWP
configuration and a per-UE measurement gap configuration (e.g.,
MeasGapConfig). The RAN node 11 further transmits, to the UE 12, a
request for transmitting an indication indicating need or no need
of a per-BWP measurement gap. The information element (IE)
corresponding to this request may be a
"PerBWP-GapIndicationRequest" IE. These configuration and request
may be transmitted using an RRC Reconfiguration message.
[0137] The UE 12 performs required internal configuration according
to the received BWP configuration, and configures a per-UE
measurement gap according to the received per-UE measurement gap
configuration (MeasGapConfig).
[0138] In Step 1603, the UE 12 transmits, to the RAN node 11,
indication indicating need or no need of a measurement gap per BWP
in the BWP set designated by the BWP configuration. The information
element (IE) corresponding to this indication may be a
"PerBWP-GapIndicationList" IE. This indication may be transmitted
using an RRC Reconfiguration Complete message.
[0139] In Step 1604, the RAN node 11 transmits, to the UE 12, a
per-BWP measurement gap configuration in response to (or in
accordance with) the received indication (perBWP-GapIndication).
The per-BWP measurement gap configuration may be "BWP specific
measurement gap configuration". The information element (IE)
corresponding to the per-BWP measurement gap configuration may be a
"measGapConfigPerBWP" IE or a "measGapConfigPerBWP-List" IE.
[0140] According to the sequence described in this embodiment, the
RAN node 11 and the UE 12 allows the UE 12 to be configured with
per-BWP measurement gaps.
Third Embodiment
[0141] This embodiment provides a method for measurement
configuration in order to deal with switching of the active BWP
among multiple BWPs included in one BWP group. A configuration
example of a radio communication network according to this
embodiment is similar to that shown in FIG. 10.
[0142] In this embodiment, in order to deal with switching of the
active BWP (not involving a change of the cell defining SSB) among
multiple
[0143] DL BWPs included in one DL BWP group, the RAN node 11
provides the UE 12, in advance, via RRC signaling (e.g., a RRC
Reconfiguration message), with multiple measurement configurations
respectively corresponding to the cases where a respective one of
the multiple DL BWPs is the active BWP. In response to switching of
the active BWP among BWPs within the BWP group for communication
between the UE 12 and the RAN, the UE 12 selects and uses a
measurement configuration corresponding to the active BWP from
among the previously received measurement configurations.
[0144] For example, when one BWP group includes first and second
BWPs, the RAN node 11 provides the UE 12, via RRC signaling (e.g.,
RRC Reconfiguration message), with a first measurement
configuration to be used when the first BWP is the active BWP and a
second measurement configuration to be used when the second BWP is
the active BWP. The UE 12 selects the first measurement
configuration when the active BWP is the first BWP, and uses it for
measurements (e.g., RLM measurement, RRM measurement, and CSI
measurement). Further, in response to switching of the active BWP
from the first BWP to the second BWP, the UE 12 autonomously
switches measurement configuration from the first measurement
configuration to the second measurement configuration. Then, the UE
12 uses, for measurements, the second measurement configuration
corresponding to the active BWP after switching.
[0145] As described earlier, switching of the active BWP within the
BWP group can be done by lower-layer signaling, such as DCI on NR
PDCCH, without using RRC signaling. Switching of the active BWP in
the BWP group is, in other words, switching of the active BWP
without change of the cell defining SSB. Specifically, the RAN node
11 and the UE 12 according to this embodiment do not need to use
RRC signaling to update the measurement configuration when
switching the active BWP within the BWP group. Thus, the RAN node
11 and the UE 12 according to this embodiment can quickly switch
the measurement configuration in response to switching of the
active BWP within the BWP group, and accordingly can quickly start
the measurement operation in accordance with the measurement
configuration corresponding to the active BWP after switching.
[0146] The multiple measurement configurations with which the RAN
node 11 provides the UE 12 in advance may include measurement gap
configurations as described in the first embodiment. In addition,
or alternatively, the multiple measurement configurations with
which the RAN node 11 provides the UE 12 in advance may include
other measurement configurations different from the measurement gap
configurations. For example, each of the multiple measurement
configurations may include a measurement configuration for RLM
(e.g., RS type, parameters for RLM (e.g., the expiration period of
an RLF timer)). Each of the multiple measurement configurations may
include a measurement configuration for RRM (e.g., RS type,
parameters for RRM reporting events, neighbor cells to be measured
(neighbor BWPs)).
[0147] To be specific, the measurement configuration (e.g.
MeasConfig IE) may include any one or combination of the following
information: [0148] Configuration regarding measurement objects
(measurement object (e.g., MeasObject IE)); [0149] Configuration
regarding measurement reporting (measurement report configuration
(e.g., ReportConfig IE)); [0150] Identifiers of respective
measurement configurations (measurement identity (e.g., Measld
IE)); [0151] Configuration regarding measurement criteria
(s-measure configuration (e.g., s-MeasureCnfig IE)); and [0152]
Configuration regarding measurement gaps (measurement gap
configuration (e.g., MeasGapConfig IE)).
[0153] The configuration regarding measurement objects (measurement
object (e.g., MeasObject IE)) may include any one or combination
of: carrier frequency information (e.g., NR ARFCN); configuration
information regarding reference signals (e.g.,
ReferenceSignalConfig IE), a list of cells to be measured; and an
offset regarding radio quality for a specific measurement reporting
event (e.g., offsetFreq). The configuration information regarding
reference signals may include at least one of: information about
measurement timing used for SSB-based measurement (e.g., SSB
measurement timing configuration (SMTC)); presence of SSB in a cell
(physical cell, BWP) to be measured (e.g., SSB presence); and
information about CSI-RS radio resources used for CSI-RS-based
measurement. Further, the offset regarding radio quality may be
indicated by a combination of an RS type to be measured and a type
of radio quality (e.g., rsrpOffsetSSB, rsrqOffsetSSB,
rsrpOffsetCSl-RS, rsrqOffsetCSI-RS).
[0154] The configuration regarding measurement reporting (e.g.,
ReportConfig IE) may include, for example, a reporting type (e.g.,
periodical, event triggered), event configuration (e.g.,
eventTriggerConfig), or periodical reporting configuration (e.g.,
peridocialReportConfig). It may further include an RS type (e.g.,
SSB (i.e. NR-SS), CSI-RS).
[0155] The identifier of each measurement configuration (e.g.,
Measld IE) may be indicated (or configured) by a combination of
configuration information regarding a measurement object and
configuration information regarding a measurement reporting.
[0156] The configuration regarding measurement criteria (e.g.,
s-MeasureCnfig IE) may include, for example, a threshold (e.g.,
RSRP threshold) that serves as a basis for determining whether to
start measurement of a neighbor cell. It may further include
information about an RS type (e.g., SSB (i.e. NR-SS), CSI-RS) to be
used for the determination, and include thresholds per RS type.
[0157] The configuration regarding measurement gaps (e.g.,
MeasGapConfig IE) may include, for example, a measurement gap for
each UE based on the serving cell (i.e. per-UE measurement gap), a
measurement gap controlled by the network (e.g. RAN node) (i.e.
network controlled small gap (NCSG)), or a measurement gap for each
component carrier in carrier aggregation (i.e. per-CC measurement
gap). In addition, or alternatively, the configuration regarding
measurement gaps may include a measurement gaps for each BWP (i.e.
per-BWP measurement gap). The per-BWP measurement gap may include
information indicating, per BWP, any one of normal measurement gap
(i.e., per UE means gap), network controlled measurement gap (i.e.,
NCSG), and no need of any measurement gaps (e.g., no gap and no
NCSG).
[0158] FIG. 17 is a sequence diagram showing a process 1700 that is
an example of operations of the RAN node 11 and the UE 12 according
to this embodiment. It is assumed in this example that a BWP group
consists of BWP #1 including an SSB and BWP #2 not including any
SSBs, and that the UE 12 first camps on BWP #1 (i.e., BWP #1 is the
active BWP). In other words, BWP #1 is the serving cell (i.e.,
physical cell) of the UE 12.
[0159] In Step 1701, the RAN node 11 transmits an RRC
Reconfiguration message to the UE 12. This RRC Reconfiguration
message includes multiple measurement configurations corresponding
to respective multiple BWPs within the BWP group. Each measurement
configuration indicates a measurement configuration to be used when
the active BWP is the corresponding BWP among the multiple BWPs
within the BWP group. This RRC Reconfiguration message may include
a request for transmitting an indication indicating need or no need
of a per-BWP measurement gap. The information element (IE)
corresponding to this request may be a
"PerBWP-GapIndicationRequest" IE.
[0160] In Step 1702, the UE 12 transmits an RRC Reconfiguration
Complete message to the RAN node 11. This RRC Reconfiguration
Complete message may include an indication indicating whether a
per-BWP measurement gap is required. The information element (IE)
corresponding to this indication may be "PerBWP-GapIndicationList"
IE. In Step 1703, the RAN node 11 transmits an RRC Reconfiguration
message including a per-BWP measurement gap configuration to the UE
12. The information element (IE) corresponding to this measurement
gap configuration may be "measGapConfigPerBWP-List" IE. The
indication in Step 1702 may be the same as the indication
indicating whether a measurement gap is required described in the
first embodiment. The measurement gap configuration in Step 1703
may be the same as the measurement gap configuration described in
the first embodiment. Note that, in this embodiment Steps 1702 and
1703 may be omitted.
[0161] The UE 12 uses the measurement configuration corresponding
to BWP #1 received in Step 1701, and performs measurement in BWP #1
(e.g., RLM measurement, CSI measurement, RRM measurement) and
measurement in BWP #2 (e.g., RRM measurement) (Step 1704).
[0162] In Step 1705, the RAN node 11 transmits control information
indicating switching of the active BWP from BWP #1 to BWP #2, i.e.,
DCI on a NR PDCCH, to the UE 12. In response to receiving this
control information (PDCCH/DCI), the UE 12 switches the active BWP
to BWP #2. Thus, BWP #2 becomes the serving cell (physical cell) of
the UE 12. Further, upon switching of the active BWP, the UE 12
switches from the measurement configuration corresponding to BWP #1
to the measurement configuration corresponding to BWP #2, and
performs measurement in BWP #2 (e.g., RLM measurement, CSI
measurement, RRM measurement) and measurement in BWP #1 (e.g., RRM
measurement) in accordance with the measurement configuration
corresponding to BWP #2 (Step 1706).
[0163] The measurement in Step 1706 may include SSB-based
measurement and CSI-RS based measurement. If the UE 12 is
configured with SSB-based measurement, the UE 12 may monitor the
SSB in BWP #1 for RLM measurement. In this case, the UE 12 may
continuously use the configuration regarding SSB-based measurement
in the measurement configuration corresponding to BWP #1 for
SSB-based measurement after switching of the active BWP from BWP #1
to BWP #2. In other words, after switching the active BWP from BWP
#1 to BWP #2, the UE 12 may use the measurement configuration
corresponding to BWP #2 in CSI-RS based measurement.
[0164] In addition, or alternatively, measurement configurations
for the component carrier frequency (measObject) may be commonly
used for measurements before and after switching of the active BWP,
except for measurement configurations specific to BWP #1 and BWP
#2.
[0165] In addition, or alternatively, after switching the active
BWP from BWP #1 to BWP #2, the UE 12 may fall back to the default
measurement gap configuration (e.g., a per-UE measurement gap
independent of the BWPs).
Fourth Embodiment
[0166] This embodiment provides a method for measurement
configuration in order to deal with switching of the active BWP
among multiple BWPs included in one BWP group. A configuration
example of a radio communication network according to this
embodiment is similar to that shown in FIG. 10.
[0167] In this embodiment, in order to deal with switching of the
active BWP (not involving a change of the cell defining SSB) among
multiple DL BWPs included in one DL BWP group, the RAN node 11
provides the UE 12, in advance, via RRC signaling (e.g., a RRC
Reconfiguration message), with a measurement configuration which
enables to replace (swap) the relationship between the serving cell
(serving BWP, active BWP) and the neighbor cell (non-serving BWP,
neighbor BWP). Upon switching of the active BWP among BWPs within
the BWP group for communication between the UE 12 and the RAN, the
UE 12 uses the previously received measurement configuration by
replacing the relationship between the serving cell (serving BWP,
active BWP) and the neighbor cell (non-serving BWP, neighbor
BWP).
[0168] For example, when one BWP group includes first and second
BWPs, the RAN node 11 provides the UE 12, via RRC signaling (e.g.,
RRC Reconfiguration message), with the measurement configuration
corresponding to the situation where the first BWP is the serving
cell (serving BWP) and the second BWP is the neighbor cell
(neighbor BWP, non-serving BWP). When the active BWP is the first
BWP, the UE 12 performs measurements (e.g., RLM measurement, RRM
measurement, CSI measurement) in accordance with this measurement
configuration. Further, upon switching of the active BWP from the
first BWP to the second BWP, the UE 12 uses the already received
measurement configuration by replacing the relationship between the
serving cell (serving BWP) and the neighbor cell (neighbor BWP,
non-serving BWP) in this measurement configuration.
[0169] The RAN node 11 and the UE 12 according to this embodiment
do not need RRC signaling for updating the measurement
configuration when switching the active BWP within the BWP group.
Thus, the RAN node 11 and the UE 12 according to this embodiment
can quickly update the measurement configuration in response to
switching of the active BWP within the BWP group, and accordingly
can quickly start the measurement operation in accordance with the
measurement configuration corresponding to the active BWP after
switching.
[0170] FIG. 18 is a sequence diagram showing a process 1800 that is
an example of operations of the RAN node 11 and the UE 12 according
to this embodiment. It is assumed in this example that a BWP group
consists of BWP #1 including a SSB and BWP #2 not including any
SSBs, and that the UE 12 first camps on BWP #1 (i.e., BWP #1 is the
active BWP).
[0171] In Step 1801, the RAN node 11 transmits an RRC
Reconfiguration message to the UE 12. This RRC Reconfiguration
message includes a measurement configuration corresponding to the
situation where BWP #1 is the serving cell (serving BWP) and BWP #2
is the neighbor cell (neighbor BWP).
[0172] Steps 1802 and 1803 are similar to Steps 1602 and 1603 of
FIG. 16. Steps 1802 and 1803 may be omitted in this embodiment
also.
[0173] The UE 12 uses the measurement configuration received in
Step 1801, and performs measurement in BWP #1 (e.g., RLM
measurement, CSI measurement, RRM measurement) and measurement in
the neighbouring cell including BWP #2 (e.g., RRM measurement)
(Step 1804).
[0174] In Step 1805, the RAN node 11 transmits control information
indicating switching of the active BWP from BWP #1 to BWP #2, i.e.,
DCI on a NR PDCCH, to the UE 12. In response to receiving this
control information (PDCCH/DCI), the UE 12 switches the active BWP
to BWP #2. Further, upon switching of the active BWP, the UE 12
uses the previously received (i.e., already stored) measurement
configuration by replacing the relationship between the serving
cell (serving BWP, active BWP) and the neighbor cell (non-serving
BWP, neighbor BWP) (Step 1806). Specifically, the UE 12 regards the
serving cell (serving BWP) in the already stored measurement
configuration as BWP #2, and performs measurement in accordance
with at least part of this measurement configuration. Stated
differently, the UE 12 regards BWP #2 as the serving cell (serving
BWP) and regards BWP #1 as the neighbor cell (neighbor BWP), and
performs measurement in accordance with at least part of the
already stored measurement configuration.
[0175] The measurement in Step 1806 may include SSB-based
measurement and CSI-RS based measurement. If the UE 12 is
configured with SSB-based measurement, the UE 12 may monitor the
SSB in BWP #1 for RLM measurement. In this case, the UE 12 may
continuously use the configuration regarding SSB-based measurement
in the measurement configuration corresponding to BWP #1 for
SSB-based measurement after switching of the active BWP from BWP #1
to BWP #2. In other words, the UE 12 may regard the serving cell
(serving BWP) in the previously received (i.e., already stored)
measurement configuration as BWP #2 for CSI-RS based measurement
after switching of the active BWP from BWP #1 to BWP #2. Stated
differently, the UE 12 regards BWP #2 as the serving cell (serving
BWP) and regards BWP #1 as the neighbor cell (neighbor BWP), and
performs measurements in accordance with at least part of the
already stored measurement configuration.
[0176] In addition, or alternatively, measurement configurations
for the carrier frequency (measObject) may be commonly used for
measurements before and after switching of the active BWP, except
for measurement configurations specific to BWP #1 and BWP #2.
[0177] In addition, or alternatively, after switching the active
BWP from BWP #1 to BWP #2, the UE 12 may fall back to the default
measurement gap configuration (e.g., a per-UE measurement gap
independent of the BWPs).
[0178] In addition, or alternatively, the RAN node 11 may transmit
a configuration of "s-measure" to the UE beforehand, using the
measurement configuration. The s-measure is an RSRP threshold and
used for determining the start of measurement of the neighbor cell.
When the RSRP of the serving cell falls below the s-measure, the UE
12 starts measurement of the neighbor cell. Further, the UE 12 may
select the target of the s-measure between the SSB (i.e. ssb-rsrp)
and the CSI-RS (i.e. csi-rsrp), and in this case, the RAN node 11
may indicate, to the UE 12, which of SSB-based and CSI-RS based the
s-measure is. The UE 12 may make determination on the s-measure
after switching of the active BWP from BWP #1 to BWP #2 by using a
measured value (e.g., SSB-based RSRP or CSI-RS based RSRP) for the
serving BWP after switching (i.e., BWP #2). Alternatively, the UE
12 may make determination on the s-measure by using a measured
value for the serving BWP before switching (i.e., BWP #1).
[0179] The RAN node 11 may notify in advance the UE 12 of the way
of treating the s-measure after switching of the active BWP (i.e.,
which of a measured value for the active BWP before switching and a
measured value for the active BWP after switching is to be used for
determination on the s-measure after switching of the active BWP).
The RAN node 11 may indicate, in the measurement configuration or
the configuration information of the BWP set, the way of treating
s-measure after switching of the active BWP. Alternatively, the UE
12 may determine the RS type of the target of the s-measure after
switching the active BWP, according to the configuration of the RS
type (e.g., SSB or CSI-RS) of the target of the s-measure before
switching the active BWP. For example, when the RS type of the
target of the s-measure before switching the active BWP is the SSB,
the UE 12 may use a measured value for the SSB for determination of
the s-measure after switching the active BWP. Not that, the UE 12
may perform measurement on the SSB in the active BWP before
switching when the active BWP after switching does not include any
SSBs, or may perform measurement on the SSB in the active BWP after
switching when the active BWP after switching includes the SSB.
[0180] For example, when the s-measure in the measurement
configuration defines an RSRP threshold for the RS (e.g., NR-SS) in
the SSB, the RAN node 11 may notify in advance the UE 12 of the
s-measure to be used after switching of the active BWP within the
BWP group in Step 1801. For example, when the new active BWP (e.g.,
active BWP #2) after switching of the active BWP within the BWP
group does not include the SSB, the RAN node 11 may configure in
advance an RSRP threshold for the CSI-RS to be used for the
s-measure after switching of the active BWP. Alternatively, when
the s-measure in the measurement configuration defines an RSRP
threshold for the CSI-RS (and when the configuration of CSI-RS in
BWP #2 is transmitted from the RAN node 11 to the UE 12), the UE 12
may continuously use the configuration of the s-measure before
switching, even after switching the active BWP from BWP #1 to BWP
#2.
[0181] The following provides configuration examples of the RAN
node 11 and the UE 12 according to the above embodiments. FIG. 19
is a block diagram showing a configuration example of the RAN node
11 according to the above embodiments. Referring to FIG. 19, the
RAN node 11 includes a Radio Frequency transceiver 1901, a network
interface 1903, a processor 1904, and a memory 1905. The RF
transceiver 1901 performs analog RF signal processing to
communicate with NG UEs including the UE 12. The RF transceiver
1901 may include a plurality of transceivers. The RF transceiver
1901 is coupled to an antenna array 1902 and the processor 1904.
The RF transceiver 1901 receives modulated symbol data from the
processor 1904, generates a transmission RF signal, and supplies
the transmission RF signal to the antenna array 1902. Further, the
RF transceiver 1901 generates a baseband reception signal based on
a reception RF signal received by the antenna array 1902, and
supplies the baseband reception signal to the processor 1904. The
RF transceiver 1901 may include an analog beamformer circuit for
beam forming. The analog beamformer circuit includes, for example,
a plurality of phase shifters and a plurality of power
amplifiers.
[0182] The network interface 1903 is used to communicate with a
network node (e.g., a control node and a transfer node of NG Core).
The network interface 1903 may include, for example, a network
interface card (NIC) conforming to the IEEE 802.3 series.
[0183] The processor 1904 performs digital baseband signal
processing (i.e., data-plane processing) and control-plane
processing for radio communication. The processor 1904 may include
a plurality of processors. The processor 1904 may include, for
example, a modem processor (e.g., a Digital Signal Processor (DSP))
that performs digital baseband signal processing and a protocol
stack processor (e.g., a Central Processing Unit (CPU) or a Micro
Processing Unit (MPU)) that performs the control-plane processing.
The processor 1904 may include a digital beamformer module for beam
forming. The digital beamformer module may include a Multiple Input
Multiple Output (MIMO) encoder and a pre-coder.
[0184] The memory 1905 is composed of a combination of a volatile
memory and a non-volatile memory. The volatile memory is, for
example, a Static Random Access Memory (SRAM), a Dynamic RAM
(DRAM), or any combination thereof. The non-volatile memory is, for
example, a mask Read Only Memory (MROM), an Electrically Erasable
Programmable ROM (EEPROM), a flash memory, a hard disc drive, or
any combination thereof. The memory 1905 may include a storage
located apart from the processor 1904. In this case, the processor
1904 may access the memory 1905 via the network interface 1903 or
an I/O interface (not shown).
[0185] The memory 1905 may store one or more software modules
(computer programs) 1906 including instructions and data to perform
processing by the RAN node 11 described in the above embodiments.
In some implementations, the processor 1904 may be configured to
load the software modules 1906 from the memory 1905 and execute the
loaded software modules, thereby performing processing of the RAN
node 11 described in the above embodiments.
[0186] Note that, if the RAN node 11 is a gNB-CU, the RAN node 11
does not need to include the RF transceiver 1901 (and the antenna
array 1902).
[0187] FIG. 20 is a block diagram showing a configuration example
of the UE 12. A Radio Frequency (RF) transceiver 2001 performs
analog RF signal processing to communicate with the NR NB 1. The RF
transceiver 2001 may include a plurality of transceivers. The
analog RF signal processing performed by the RF transceiver 2001
includes frequency up-conversion, frequency down-conversion, and
amplification. The RF transceiver 2001 is coupled to an antenna
array 2002 and a baseband processor 2003. The RF transceiver 2001
receives modulated symbol data (or OFDM symbol data) from the
baseband processor 2003, generates a transmission RF signal, and
supplies the transmission RF signal to the antenna array 2002.
Further, the RF transceiver 2001 generates a baseband reception
signal based on a reception RF signal received by the antenna array
2002, and supplies the baseband reception signal to the baseband
processor 2003. The RF transceiver 2001 may include an analog
beamformer circuit for beam forming. The analog beamformer circuit
includes, for example, a plurality of phase shifters and a
plurality of power amplifiers.
[0188] The baseband processor 2003 performs digital baseband signal
processing (i.e., data-plane processing) and control-plane
processing for radio communication. The digital baseband signal
processing includes (a) data compression/decompression, (b) data
segmentation/concatenation, (c) composition/decomposition of a
transmission format (i.e., transmission frame), (d) channel
coding/decoding, (e) modulation (i.e., symbol
mapping)/demodulation, and (f) generation of OFDM symbol data
(i.e., baseband OFDM signal) by Inverse Fast Fourier Transform
(IFFT). Meanwhile, the control-plane processing includes
communication management of layer 1 (e.g., transmission power
control), layer 2 (e.g., radio resource management and hybrid
automatic repeat request (HARQ) processing), and layer 3 (e.g.,
signaling regarding attach, mobility, and call management).
[0189] The digital baseband signal processing by the baseband
processor 2003 may include, for example, signal processing of a
Service Data Adaptation Protocol (SDAP) layer, a Packet Data
Convergence Protocol (PDCP) layer, a Radio Link Control (RLC)
layer, a MAC layer, and a PHY layer. Further, the control-plane
processing performed by the baseband processor 2003 may include
processing of a Non-Access Stratum (NAS) protocol, an RRC protocol,
and MAC CEs.
[0190] The baseband processor 2003 may perform MIMO encoding and
pre-coding for beam forming.
[0191] The baseband processor 2003 may include a modem processor
(e.g., DSP) that performs the digital baseband signal processing
and a protocol stack processor (e.g., a CPU or an MPU) that
performs the control-plane processing. In this case, the protocol
stack processor, which performs the control-plane processing, may
be integrated with an application processor 2004 described in the
following.
[0192] The application processor 2004 is also referred to as a CPU,
an MPU, a microprocessor, or a processor core. The application
processor 2004 may include a plurality of processors (processor
cores). The application processor 2004 loads a system software
program (Operating System (OS)) and various application programs
(e.g., a call application, a WEB browser, a mailer, a camera
operation application, and a music player application) from a
memory 2006 or from another memory (not shown) and executes these
programs, thereby providing various functions of the UE 12.
[0193] In some implementations, as represented by a dashed line
(2005) in FIG. 20, the baseband processor 2003 and the application
processor 2004 may be integrated on a single chip. In other words,
the baseband processor 2003 and the application processor 2004 may
be implemented in a single System on Chip (SoC) device 2005. An SoC
device may be referred to as a system Large Scale Integration (LSI)
or a chipset.
[0194] The memory 2006 is a volatile memory, a non-volatile memory,
or a combination thereof. The memory 2006 may include a plurality
of memory devices that are physically independent from each other.
The volatile memory is, for example, an SRAM, a DRAM, or any
combination thereof. The non-volatile memory is, for example, an
MROM, an EEPROM, a flash memory, a hard disc drive, or any
combination thereof. The memory 2006 may include, for example, an
external memory device that can be accessed from the baseband
processor 2003, the application processor 2004, and the SoC 2005.
The memory 2006 may include an internal memory device that is
integrated in the baseband processor 2003, the application
processor 2004, or the SoC 2005. Further, the memory 2006 may
include a memory in a Universal Integrated Circuit Card (UICC).
[0195] The memory 2006 may store one or more software modules
(computer programs) 2007 including instructions and data to perform
the processing by the UE 12 described in the above embodiments. In
some implementations, the baseband processor 2003 or the
application processor 2004 may load these software modules 2007
from the memory 2006 and execute the loaded software modules,
thereby performing the processing of the UE 12 described in the
above embodiments with reference to the drawings.
[0196] Note that, the control plane processes and operations
described in the above embodiments can be achieved by the elements
other than the RF transceiver 2001 and the antenna array 2202,
i.e., achieved by the memory storing the software modules 2007 and
at least one of the baseband processor 2003 and the application
processor 2004.
[0197] As described above with reference to FIGS. 19 and 20, each
of the processors included in the RAN node 11 and the UE 2
according to the above embodiments executes one or more programs
including instructions to cause a computer to perform an algorithm
described with reference to the drawings. The program(s) can be
stored and provided to a computer using any type of non-transitory
computer readable media. Non-transitory computer readable media
include any type of tangible storage media. Examples of
non-transitory computer readable media include magnetic storage
media (such as flexible disks, magnetic tapes, hard disk drives,
etc.), optical magnetic storage media (e.g., magnetooptical disks),
Compact Disc Read Only Memory (CD-ROM), CD-R, CD-R/W, and
semiconductor memories (such as mask ROM, Programmable ROM (PROM),
Erasable PROM (EPROM), flash ROM, Random Access Memory (RAM),
etc.). The program(s) may be provided to a computer using any type
of transitory computer readable media. Examples of transitory
computer readable media include electric signals, optical signals,
and electromagnetic waves. Transitory computer readable media can
provide the program to a computer via a wired communication line
(e.g., electric wires, and optical fibers) or a wireless
communication line.
OTHER EMBODIMENTS
[0198] Each of the above-described embodiments may be used
individually, or two or more embodiments may be appropriately
combined with one another.
[0199] In the above embodiments, switching of the active BWP by DCI
transmitted on a NR PDCCH is described. Note that, however,
switching of the active BWP in the above-described embodiments may
be done by a MAC CE or a timer (e.g., BWP Inactivity Timer).
[0200] The above embodiments are described mainly based on the
assumption that only one BWP is activated for each UE (i.e. 1
active BWP per UE). However, the methods described in the above
embodiments are also applicable to the case where multiple BWPs are
simultaneously activated for a UE as a matter of course. For
example, there are multiple active BWPs in a BWP set. Further,
there are multiple active BWPs each corresponding to a respective
one of multiple BWP groups configured in a BWP set, or there are
multiple active BWPs in a BWP group.
[0201] The above embodiments may be applied also to MR-DC (e.g.,
EN-DC) and NR-NR DC. For example, in EN-DC, the MeNB, the SgNB and
the UE may operate as follows. First, the UE transmits its NR
capability (e.g., UE NR radio capability information) to the MeNB
via RRC signaling (e.g., UE Capability Information message), and
the MeNB forwards the NR capability to the SgNB. Further, the MeNB
transmits to the UE, via an LTE RRC Connection Reconfiguration
message, a request for transmitting an indication of need or no
need of a measurement gap for each BWP in the SCG of NR (e.g.,
"PerBWP-GapIndicationRequest" IE). The SgNB may trigger the MeNB to
transmit this request by using an X2 message. In response to
receiving this request, the UE transmits an indication indicating
need or no need of a per-BWP measurement gap (e.g.,
"perBWP-GapIndicationList" IE) to the MeNB via an LTE RRC
Connection Reconfiguration Complete message. The MeNB forwards this
indication (e.g., "perBWP-GapIndicationList" IE) received from the
UE to the SgNB. Then, the SgNB sends a configuration of a per-BWP
measurement gap (e.g., "measGapConfigPerBWP-List" IE) to the MeNB,
and the MeNB transmits this configuration to the UE via an LTE RRC
Connection Reconfiguration message. The information transmitted by
the UE and the SgNB may be encoded by NR RRC.
[0202] Alternatively, in EN-DC, the MeNB, the SgNB and the UE may
operate as follows. The SgNB may use a transparent RRC container to
transmit a "PerBWP-GapIndicationRequest" and a
"measGapConfigPerBWP-List" to the UE through the MeNB. To be
specific, the SgNB includes an NR RRC Reconfiguration message
containing a "PerBWP-GapIndicationRequest" in a transparent RRC
container, and sends this transparent RRC container to the MeNB.
The MeNB sends the transparent RRC container (which contains the
"PerBWP-GapIndicationRequest") received from the SgNB to the UE via
an LTE RRC Connection Reconfiguration message. The UE sends an NR
RRC Reconfiguration Complete message, which contains a
"perBWP-GapIndicationList", to the MeNB via an LTE RRC Connection
Reconfiguration Complete message. The MeNB forwards to the SgNB the
NR RRC Reconfiguration Complete message containing the
"perBWP-GapIndicationList". After that, the SgNB includes a NR RRC
Reconfiguration message containing a "measGapConfigPerBWP-List" in
a transparent RRC container, and send this transparent RRC
container to the MeNB. The MeNB sends the transparent RRC container
(which contains the "measGapConfigPerBWP-List") received from the
SgNB to the UE via an LTE RRC Connection Reconfiguration message.
Note that, to achieve this, X2 messages (i.e., an SN MODIFICATION
REQUIRED, an SN MODIFICATION REQUEST, an SN MODIFICATION REQUEST
ACKNOWLEDGEMENT, and an SN MODIFICATION COMPLETE, respectively) in
the SN (i.e. SgNB) Initiated SN Modification procedure may be
used.
[0203] Further alternatively, in EN-DC, the SgNB and the UE may use
a direct radio bearer between the SgNB and the UE established in
the SCG to transmit a request for an indication of a per-BWP
measurement gap, transmit an indication of need or no need of a
per-BWP measurement gap, and transmit a per-BWP measurement gap
configuration. This radio bearer may be a Signalling Radio Bearer 3
(SRB3). To be specific, the SgNB transmits a
"PerBWP-GapIndicationRequest" to the UE via an NR RRC
Reconfiguration message on the SRB3. The UE transmits a
"perBWP-GapIndicationList" to the SgNB via an NR RRC
Reconfiguration Complete message on the SRB3. The SgNB then
transmits a "measGapConfigPerBWP-List" to the UE via an NR RRC
Reconfiguration message on the SRB3.
[0204] Although the term "cell defining SSB" is used in the above
embodiments, it may be referred to as a cell representative SSB
because it is an SSB that is representative of a BWP corresponding
to the cell from the UE perspective (i.e., physical cell) or of a
BWP group corresponding to a set of the physical cells.
Alternatively, the cell defining SSB may be referred to as a
cell-specific SSB because it specifies a representative cell
(physical cell) including this SSB. Further, the cell defining SSB
may be referred to as a serving SSB because it is an SSB to be
monitored when the UE camps on a BWP or BWP group including this
SSB.
[0205] The sub-PCI described in the above embodiments may be
associated with a BWP index.
[0206] The base BWP described in the above embodiments may be
referred to as a default BWP, an initial BWP, a reference BWP, a
primary BWP, an anchor BWP, or a master BWP. Specifically, the BWP
on which the UE first camps when accessing the RAN node for the
first time (i.e., when transitioning from Idle mode to Connected
mode) may be referred to as a base BWP, a default BWP, an initial
BWP, a reference BWP, a primary BWP, an anchor BWP, or a master
BWP. In addition, or alternatively, a BWP which is not the base BWP
among multiple BWPs included in one system bandwidth may be
referred to as a sub-BWP, a secondary BWP, or a slave BWP.
[0207] Further, the above-described embodiments are merely examples
of applications of the technical ideas obtained by the inventor.
These technical ideas are not limited to the above-described
embodiments and various modifications can be made thereto.
[0208] For example, the whole or part of the above embodiments can
be described as, but not limited to, the following supplementary
notes.
(Supplementary Note 1)
[0209] A radio terminal comprising:
[0210] a memory; and
[0211] at least one processor coupled to the memory and configured
to: [0212] transmit, to a radio access network (RAN) node in a
radio access network (RAN), an indication indicating whether a
measurement gap for inter-bandwidth part (BWP) measurement among
BWPs included in a plurality of downlink BWPs is required, the
downlink BWPs being included within one system bandwidth; and
[0213] receive, from the RAN node, a measurement configuration
including a measurement gap configuration for one or more BWPs
included in the downlink BWPs.
(Supplementary Note 2)
[0214] The radio terminal according to Supplementary note 1,
wherein the indication indicates whether, when one of the downlink
BWPs is activated for the radio terminal, the radio terminal needs
a measurement gap for measurement of one or more BWPs different
from the activated BWP.
(Supplementary Note 3)
[0215] The radio terminal according to Supplementary note 1,
wherein the indication indicates, per BWP, whether the radio
terminal needs a measurement gap for one or more BWPs that are
included in the downlink BWPs but are different from a BWP
activated for the radio terminal.
(Supplementary Note 4)
[0216] The radio terminal according to Supplementary note 1,
wherein
[0217] the indication includes information about a BWP combination
indicating a combination of two or more BWPs included in the
downlink BWPs, and
[0218] the indication indicates whether, when one BWP of each BWP
combination is activated for the radio terminal, the radio terminal
needs a measurement gap for measurement of each remaining BWP of
the BWP combination.
(Supplementary Note 5)
[0219] The radio terminal according to any one of Supplementary
notes 1 to 4, wherein the at least one processor is configured to,
in response to switching of an active BWP for communication between
the radio terminal and the RAN among the downlink BWPs, use a
measurement gap configuration corresponding to the active BWP in
accordance with the measurement gap configuration.
(Supplementary Note 6)
[0220] The radio terminal according to any one of Supplementary
notes 1 to 5, wherein the measurement gap configuration indicates a
configuration regarding a measurement gap to be used by the radio
terminal to measure one or more BWPs different from an
activated
[0221] BWP when one of the downlink BWPs is activated for the radio
terminal.
(Supplementary Note 7)
[0222] The radio terminal according to Supplementary note 6,
wherein the measurement gap configuration indicates at least one
of: presence or absence of the measurement gap; a length of the
measurement gap; and a pattern of the measurement gap.
(Supplementary Note 8)
[0223] The radio terminal according to any one of Supplementary
notes 1 to 7, wherein the downlink BWPs are associated with one
cell-defining signal block (SSB).
(Supplementary Note 9)
[0224] The radio terminal according to Supplementary note 8,
wherein
[0225] the measurement gap configuration includes a first
measurement gap configuration and a second measurement gap
configuration respectively for a first downlink BWP and a second
downlink BWP included in the downlink BWPs,
[0226] the at least one processor is configured to receive the
first and second measurement gap configurations from the RAN node
via Radio Resource Control (RRC) signaling, and
[0227] the at least one processor is further configured to: [0228]
when the first downlink BWP is activated for communication with the
RAN, use the first measurement gap configuration to measure another
downlink BWP; [0229] receive, from the RAN node, control
information indicating switching of an active BWP from the first
downlink BWP to the second downlink BWP without change of the
cell-defining SSB, and [0230] in response to receiving the control
information, switch the active BWP from the first downlink BWP to
the second downlink BWP for communication with the RAN, and use the
second measurement gap configuration instead of the first
measurement gap configuration to measure another downlink BWP.
(Supplementary Note 10)
[0231] The radio terminal according to Supplementary note 9,
wherein the control information is a non-RRC message.
(Supplementary Note 11)
[0232] A radio access network (RAN) node placed in a radio access
network (RAN), the RAN node comprising:
[0233] a memory; and
[0234] at least one processor coupled to the memory and configured
to: [0235] receive, from a radio terminal, an indication indicating
whether a measurement gap for inter-bandwidth part (BWP)
measurement among BWPs included in a plurality of downlink BWPs is
required, the downlink BWPs being included within one system
bandwidth; and [0236] transmit, to the radio terminal, a
measurement configuration including a measurement gap configuration
for one or more BWPs included in the downlink BWPs.
(Supplementary Note 12)
[0237] The RAN node according to Supplementary note 11, wherein the
indication indicates whether, when one of the downlink BWPs is
activated for the radio terminal, the radio terminal needs a
measurement gap for measurement of one or more BWPs different from
the activated BWP.
(Supplementary Note 13)
[0238] The RAN node according to Supplementary note 11, wherein the
indication indicates, per BWP, whether the radio terminal needs a
measurement gap for one or more BWPs that are included in the
downlink BWPs but are different from a BWP activated for the radio
terminal.
(Supplementary Note 14)
[0239] The RAN node according to Supplementary note 11, wherein
[0240] the indication includes information about a BWP combination
indicating a combination of two or more BWPs included in the
downlink BWPs, and
[0241] the indication indicates whether, when one BWP of each BWP
combination is activated for the radio terminal, the radio terminal
needs a measurement gap for measurement of each remaining BWP of
the BWP combination.
(Supplementary Note 15)
[0242] The RAN node according to any one of Supplementary notes 11
to 14, wherein the measurement gap configuration indicates a
configuration regarding a measurement gap to be used by the radio
terminal to measure one or more BWPs different from an activated
BWP when one of the downlink BWPs is activated for the radio
terminal.
(Supplementary Note 16)
[0243] The RAN node according to Supplementary note 15, wherein the
measurement gap configuration indicates at least one of: presence
or absence of the measurement gap; a length of the measurement gap;
and a pattern of the measurement gap.
(Supplementary Note 17)
[0244] The RAN node according to any one of Supplementary notes 11
to 16, wherein the downlink BWPs are associated with one
cell-defining synchronization signal block (SSB).
(Supplementary Note 18)
[0245] The RAN node according to Supplementary note 17, wherein
[0246] the measurement gap configuration includes a first
measurement gap configuration and a second measurement gap
configuration respectively for a first downlink BWP and a second
downlink BWP included in the downlink BWPs,
[0247] the at least one processor is configured to transmit the
first and second measurement gap configurations to the radio
terminal via Radio Resource Control (RRC) signaling,
[0248] the at least one processor is further configured to: [0249]
when the first downlink BWP is activated for communication with the
RAN, communicate with the radio terminal while taking into account
that the first measurement gap configuration is used by the radio
terminal to measure another downlink BWP, and [0250] transmit, to
the radio terminal, control information indicating switching of an
active BWP from the first downlink BWP to the second downlink BWP
without change of the cell-defining SSB,
[0251] wherein the control information triggers the radio terminal
to switch the active BWP from the first downlink BWP to the second
downlink BWP for communication with the RAN, and triggers the radio
terminal to use the second measurement gap configuration instead of
the first measurement gap configuration to measure another downlink
BWP.
(Supplementary Note 19)
[0252] The RAN node according to Supplementary note 18, wherein the
control information is a non-RRC message.
(Supplementary Note 20)
[0253] A method for a radio terminal, the method comprising:
[0254] transmitting, to a radio access network (RAN) node in a
radio access network (RAN), an indication indicating whether a
measurement gap for inter-bandwidth part (BWP) measurement among
BWPs included in a plurality of downlink BWPs is required, the
downlink BWPs being included within one system bandwidth; and
[0255] receiving, from the RAN node, a measurement configuration
including a measurement gap configuration for one or more BWPs
included in the downlink BWPs.
(Supplementary Note 21)
[0256] A method for a radio access network (RAN) node placed in a
radio access network (RAN), the method comprising:
[0257] receiving, from a radio terminal, an indication indicating
whether a measurement gap for inter-bandwidth part (BWP)
measurement among BWPs included in a plurality of downlink BWPs is
required, the downlink BWPs being included within one system
bandwidth; and
[0258] transmitting, to the radio terminal, a measurement
configuration including a measurement gap configuration for one or
more BWPs included in the downlink BWPs.
(Supplementary Note 22)
[0259] A program for causing a computer to perform a method for a
radio terminal, wherein the method comprises:
[0260] transmitting, to a radio access network (RAN) node in a
radio access network (RAN), an indication indicating whether a
measurement gap for inter-bandwidth part (BWP) measurement among
BWPs included in a plurality of downlink BWPs is required, the
downlink BWPs being included within one system bandwidth; and
[0261] receiving, from the RAN node, a measurement configuration
including a measurement gap configuration for one or more BWPs
included in the downlink BWPs.
(Supplementary Note 23)
[0262] A program for causing a computer to perform a method for a
radio access network (RAN) node placed in a radio access network
(RAN), wherein the method comprises:
[0263] receiving, from a radio terminal, an indication indicating
whether a measurement gap for inter-bandwidth part (BWP)
measurement among BWPs included in a plurality of downlink BWPs is
required, the downlink BWPs being included within one system
bandwidth; and
[0264] transmitting, to the radio terminal, a measurement
configuration including a measurement gap configuration for one or
more BWPs included in the downlink BWPs.
(Supplementary Note 24)
[0265] A radio terminal comprising:
[0266] a memory; and
[0267] at least one processor coupled to the memory and configured
to: [0268] receive from a radio access network (RAN) node in a
radio access network (RAN), via Radio Resource Control (RRC)
signaling, a first measurement configuration and a second
measurement configuration respectively for a first downlink
bandwidth part (BWP) and a second downlink BWP, the first and
second downlink BWPs being included in one system bandwidth and
being associated with one cell-defining synchronization signal
block (SSB); [0269] use the first measurement configuration when
the first downlink BWP is activated for communication with the RAN;
[0270] receive, from the RAN node, control information indicating
switching of an active BWP from the first downlink BWP to the
second downlink BWP without change of the cell-defining SSB; and
[0271] in response to receiving the control information, switch the
active BWP from the first downlink BWP to the second downlink BWP
for communication with the RAN, and use the second measurement
configuration instead of the first measurement configuration.
(Supplementary Note 25)
[0272] The radio terminal according to Supplementary note 24,
wherein the control information is a non-RRC message.
(Supplementary Note 26)
[0273] The radio terminal according to Supplementary note 24 or 25,
wherein each of the first and second measurement configurations
includes a measurement gap configuration.
(Supplementary Note 27)
[0274] A radio access network (RAN) node comprising:
[0275] a memory; and
[0276] at least one processor coupled to the memory and configured
to: [0277] transmit to a radio terminal, via Radio Resource Control
(RRC) signaling, a first measurement configuration and a second
measurement configuration respectively for a first downlink
bandwidth part (BWP) and a second downlink BWP, the first and
second downlink BWPs being included in one system bandwidth and
being associated with one cell-defining synchronization signal
block (SSB); [0278] when the first downlink BWP is activated for
communication with a radio access network (RAN), communicate with
the radio terminal while taking into account that the first
measurement configuration is used by the radio terminal; and [0279]
transmit, to the radio terminal, control information indicating
switching of an active BWP from the first downlink BWP to the
second downlink BWP without change of the cell-defining SSB,
[0280] wherein the control information triggers the radio terminal
to switch the active BWP from the first downlink BWP to the second
downlink BWP for communication with the RAN, and triggers the radio
terminal to use the second measurement configuration instead of the
first measurement configuration.
(Supplementary Note 28)
[0281] The RAN node according to Supplementary note 27, wherein the
control information is a non-RRC message.
(Supplementary Note 29)
[0282] The RAN node according to Supplementary note 27 or 28,
wherein each of the first and second measurement configurations
includes a measurement gap configuration.
(Supplementary Note 30)
[0283] A method for a radio terminal, the method comprising:
[0284] receiving from a radio access network (RAN) node in a radio
access network (RAN), via Radio Resource Control (RRC) signaling, a
first measurement configuration and a second measurement
configuration respectively for a first downlink bandwidth part
(BWP) and a second downlink BWP, the first and second downlink BWPs
being included in one system bandwidth and being associated with
one cell-defining synchronization signal block (SSB);
[0285] using the first measurement configuration when the first
downlink BWP is activated for communication with the RAN;
[0286] receiving, from the RAN node, control information indicating
switching of an active BWP from the first downlink BWP to the
second downlink BWP without change of the cell-defining SSB;
and
[0287] in response to receiving the control information, switching
the active BWP from the first downlink BWP to the second downlink
BWP for communication with the RAN, and using the second
measurement configuration instead of the first measurement
configuration.
(Supplementary Note 31)
[0288] A method for a radio access network (RAN) node, the method
comprising:
[0289] transmitting to a radio terminal, via Radio Resource Control
(RRC) signaling, a first measurement configuration and a second
measurement configuration respectively for a first downlink
bandwidth part (BWP) and a second downlink BWP, the first and
second downlink BWPs being included in one system bandwidth and
being associated with one cell-defining synchronization signal
block (SSB);
[0290] when the first downlink BWP is activated for communication
with a radio access network (RAN), communicating with the radio
terminal while taking into account that the first measurement
configuration is used by the radio terminal; and
[0291] transmitting, to the radio terminal, control information
indicating switching of an active BWP from the first downlink BWP
to the second downlink BWP without change of the cell-defining
SSB,
[0292] wherein the control information triggers the radio terminal
to switch the active BWP from the first downlink BWP to the second
downlink BWP for communication with the RAN, and triggers the radio
terminal to use the second measurement configuration instead of the
first measurement configuration.
(Supplementary Note 32)
[0293] A program for causing a computer to perform a method for a
radio terminal, wherein the method comprises:
[0294] receiving from a radio access network (RAN) node in a radio
access network (RAN), via Radio Resource Control (RRC) signaling, a
first measurement configuration and a second measurement
configuration respectively for a first downlink bandwidth part
(BWP) and a second downlink BWP, the first and second downlink BWPs
being included in one system bandwidth and being associated with
one cell-defining synchronization signal block (SSB);
[0295] using the first measurement configuration when the first
downlink BWP is activated for communication with the RAN;
[0296] receiving, from the RAN node, control information indicating
switching of an active BWP from the first downlink BWP to the
second downlink BWP without change of the cell-defining SSB;
and
[0297] in response to receiving the control information, switching
the active BWP from the first downlink BWP to the second downlink
BWP for communication with the RAN, and using the second
measurement configuration instead of the first measurement
configuration.
(Supplementary Note 33)
[0298] A non-transitory computer readable medium storing a program
for causing a computer to perform a method for a radio access
network (RAN) node, wherein the method comprises:
[0299] transmitting to a radio terminal, via Radio Resource Control
(RRC) signaling, a first measurement configuration and a second
measurement configuration respectively for a first downlink
bandwidth part (BWP) and a second downlink BWP, the first and
second downlink BWPs being included in one system bandwidth and
being associated with one cell-defining synchronization signal
block (SSB);
[0300] when the first downlink BWP is activated for communication
with a radio access network (RAN), communicating with the radio
terminal while taking into account that the first measurement
configuration is used by the radio terminal; and
[0301] transmitting, to the radio terminal, control information
indicating switching of an active BWP from the first downlink BWP
to the second downlink BWP without change of the cell-defining SSB,
wherein the control information triggers the radio terminal to
switch the active BWP from the first downlink BWP to the second
downlink BWP for communication with the RAN, and triggers the radio
terminal to use the second measurement configuration instead of the
first measurement configuration.
(Supplementary Note 34)
[0302] A radio terminal comprising:
[0303] a memory; and
[0304] at least one processor coupled to the memory and configured
to: [0305] receive, from a radio access network (RAN) node in a
radio access network (RAN), via Radio Resource Control (RRC)
signaling, a measurement configuration for a first downlink
bandwidth part (BWP) and a second downlink BWP, the first and
second downlink BWPs being included in one system bandwidth and
being associated with one cell-defining synchronization signal
block (SSB); [0306] use the measurement configuration when the
first downlink BWP is activated for communication with the RAN;
[0307] receive, from the RAN node, control information indicating
switching of an active BWP from the first downlink BWP to the
second downlink BWP without change of the cell-defining SSB; and
[0308] in response to receiving the control information, switch the
active BWP from the first downlink BWP to the second downlink BWP
for communication with the RAN, and use the measurement
configuration by replacing a relationship between a serving cell
and a neighbor cell in the measurement configuration.
(Supplementary Note 35)
[0309] The radio terminal according to Supplementary note 34,
wherein the control information is a non-RRC message.
(Supplementary Note 36)
[0310] A method for a radio terminal, the method comprising:
[0311] receiving, from a radio access network (RAN) node in a radio
access network (RAN), via Radio Resource Control (RRC) signaling, a
measurement configuration for a first downlink bandwidth part (BWP)
and a second downlink BWP, the first and second downlink BWPs being
included in one system bandwidth and being associated with one
cell-defining synchronization signal block (SSB);
[0312] using the measurement configuration when the first downlink
BWP is activated for communication with the RAN;
[0313] receiving, from the RAN node, control information indicating
switching of an active BWP from the first downlink BWP to the
second downlink BWP without change of the cell-defining SSB;
and
[0314] in response to receiving the control information, switching
the active BWP for communication with the RAN from the first
downlink BWP to the second downlink BWP, and using the measurement
configuration by replacing a relationship between a serving cell
and a neighbor cell in the measurement configuration.
(Supplementary Note 37)
[0315] A program for causing a computer to perform a method for a
radio terminal, wherein the method comprises:
[0316] receiving, from a radio access network (RAN) node in a radio
access network (RAN), via Radio Resource Control (RRC) signaling, a
measurement configuration for a first downlink bandwidth part (BWP)
and a second downlink BWP, the first and second downlink BWPs being
included in one system bandwidth and being associated with one
cell-defining synchronization signal block (SSB);
[0317] using the measurement configuration when the first downlink
BWP is activated for communication with the RAN;
[0318] receiving, from the RAN node, control information indicating
switching of an active BWP from the first downlink BWP to the
second downlink BWP without change of the cell-defining SSB;
and
[0319] in response to receiving the control information, switching
the active BWP for communication with the RAN from the first
downlink BWP to the second downlink BWP, and using the measurement
configuration by replacing a relationship between a serving cell
and a neighbor cell in the measurement configuration.
[0320] This application is based upon and claims the benefit of
priority from Japanese Patent Application No. 2017-218039, filed on
Nov. 13, 2017, the disclosure of which is incorporated herein in
its entirety by reference.
REFERENCE SIGNS LIST
[0321] 11 RAN NODE [0322] 12 UE [0323] 1904 PROCESSOR [0324] 1905
MEMORY [0325] 2003 BASEBAND PROCESSOR [0326] 2004 APPLICATION
PROCESSOR
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