Title of invention: Wireless terminal and method thereof
Technical field
[0001]
　The present disclosure relates to wireless communication systems, and more particularly to wireless communication systems that use one or more bandwidth parts configured within one carrier band.
Background technology
[0002]
　The 3rd Generation Partnership Project (3GPP) is working on standardization of the 5th generation mobile communication system (5G) for introduction after 2020. 5G is a combination of continuous improvement and evolution (enhancement/evolution) of LTE and LTE-Advanced and innovative improvement and development by introducing a new 5G air interface (new Radio Access Technology (RAT)). It is supposed to be done. The new RAT is, for example, a frequency band higher than the frequency band (eg, 6 GHz or less) targeted for continuous development of LTE/LTE-Advanced, for example, a centimeter wave band of 10 GHz or more and a millimeter wave band of 30 GHz or more. Support wave bands.
[0003]
　In this specification, the fifth-generation mobile communication system is also referred to as a 5G System or a Next Generation (NextGen) System (NG System). The new RAT for 5G System is called New Radio (NR), 5G RAT, or NG RAT. The new Radio Access Network (RAN) for 5G System is called 5G-RAN or NextGen RAN (NG RAN). The new base station in 5G-RAN is called NR NodeB (NR NB) or gNodeB (gNB). The new core network for 5G System is called 5G Core Network (5G-CN or 5GC) or NextGen Core (NG Core). A wireless terminal (User Equipment (UE)) connected to the 5G System is called a 5G UE, a NextGen UE (NG UE), or simply a UE. Formal names such as RAT, UE, radio access network, core network, network entities (nodes), and protocol layers for 5G System will be determined in the future as the standardization work progresses.
[0004]
　The term “LTE” used in the present specification includes improvements and developments of LTE and LTE-Advanced to enable interworking with 5G System, unless otherwise specified. Improvements and developments of LTE and LTE-Advanced for interworking with 5G System are also called LTE-Advanced Pro, LTE+, or enhanced LTE (eLTE). Further, as used herein, "Evolved Packet Core (EPC)", "Mobility Management Entity (MME)", "Serving Gateway (S-GW)", and "Packet Data Network (PDN) Gateway (P-GW )” and other terms relating to LTE networks or logical entities include these improvements and developments to enable interworking with 5G Systems unless otherwise noted. The improved EPC, MME, S-GW, and P-GW are, for example, enhanced EPC (eEPC), enhanced MME (eMME), enhanced S-GW (eS-GW), and enhanced P-GW (eP-GW). ) Is also called.
[0005]
　In LTE and LTE-Advanced, for quality of service (QoS) and packet routing, bearers for each QoS class and for each PDN connection are RAN (ie, Evolved Universal Terrestrial RAN (E-UTRAN)) and core network (ie, EPC) used both. That is, in the Bearer-based QoS (or per-bearer QoS) concept, one or more Evolved Packet System (EPS) bearers are set between the UE and the P-GW in the EPC, and a plurality of Evolved Packet System (EPS) bearers having the same QoS class are set. Service data flows (Service Data Flows (SDFs)) are transferred through one EPS bearer that satisfies these QoS.
[0006]
　On the other hand, in 5G System, although radio bearers may be used in NG-RAN, it is considered that bearers are not used in the 5GC and at the interface between 5GC and NG-RAN. Specifically, PDU flows are defined instead of EPS bearer, and one or more SDFs are mapped to one or more PDU flows. The PDU flow between the 5G UE and the user plane termination entity (ie, the entity corresponding to the P-GW in EPC) in the NG Core corresponds to the EPS bearer in the EPS Bearer-based QoS concept. PDU flow corresponds to the finest granularity of packet forwarding and treatment within a 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 on a PDU flow basis. The association between the 5G UE and the data network is called a PDU session. The PDU session is a term corresponding to PDN connection of LTE and LTE-Advanced. Multiple PDU flows can be configured within one PDU session. The 3GPP specification defines 5G QoS Indicator (5QI) corresponding to LTE QCI for 5G System.
[0007]
　The PDU flow is also called "QoS flow". The QoS flow is the finest granularity of the QoS treatment within the 5G system. User plane traffic with the same N3 marking value in the PDU session corresponds to the QoS flow. The N3 marking corresponds to the above PDU flow ID and is also called a QoS flow Identity (QFI), and is also called a Flow Identification Indicator (FII). Here, there is a one-to-one mapping between at least each 5QI specified in the specification and the corresponding QFI having the same value (number) as this (ie, one-to-one mapping).
[0008]
　Figure 1 shows the basic architecture of a 5G system. The UE establishes one or more signaling radio bearers (SRBs) and one or more data radio bearers (DRBs) with the gNB. 5GC and gNB establish the control plane interface and user plane interface for the UE. The control plane interface between 5GC and gNB (ie, RAN) is called N2 interface, NG2 interface, or NG-c interface. It transfers Non-Access Stratum (NAS) information and controls between 5GC and gNB. Used for information (eg, N2 AP Information Element). The user plane interface between the 5GC and the gNB (ie, RAN) is called N3 interface, NG3 interface, or NG-u interface, and packets of one or more PDU flows in the PDU session of the UE. Used to transfer.
[0009]
　It should be noted that the architecture shown in FIG. 1 is only one of multiple 5G architecture options (or deployment scenarios). The architecture shown in FIG. 1 is an architecture called "Standalone NR (in NextGen System)" or "Option 2." 3GPP is also exploring some network architectures for multi-connectivity operation using E-UTRA and NR radio access technologies. A typical example of multi-connection operation is a dual connection (Dual Connectivity (DC) in which one master node (Master node (MN)) and one secondary node (Secondary node (SN)) cooperate with each other to simultaneously communicate with one UE. )). Dual connection operation using E-UTRA and NR radio access technologies is called Multi-RAT Dual Connectivity (MR-DC). MR-DC is a dual connectivity between an E-UTRA node and an NR node (E-UTRA and NR nodes).
[0010]
　In MR-DC, one of E-UTRA node (ie, eNB) and NR node (ie, gNB) operates as a master node (Master node (MN)), and the other operates as a secondary node (Secondary node (SN)). , And at least the MN is connected to the core network. The MN provides the UE with one or more Master Cell Group (MCG) cells, and the SN provides the UE with one or more Secondary Cell Group (SCG) cells. MR-DC includes "MR-DC with the EPC" and "MR-DC with the 5GC".
[0011]
　MR-DC with the EPC includes E-UTRA-NR Dual Connectivity (EN-DC). In EN-DC, the UE is connected to the eNB that operates as the MN and the gNB that operates as the SN. Furthermore, eNB (ie, Master eNB) is connected to EPC, gNB (ie Secondary gNB) is connected to Master eNB via X2 interface.
[0012]
　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 NE-DC, UE is connected to gNB operating as MN and eNB operating as SN, gNB (ie, Master gNB) is connected to 5GC, eNB (ie Secondary eNB) is Master gNB via Xn interface. Connected. On the other hand, in NG-EN-DC, UE is connected to eNB operating as MN and gNB operating as SN, eNB (ie, Master eNB) is connected to 5GC, gNB (ie Secondary gNB) is via Xn interface. Connected to the Master eNB.
[0013]
　2, 3 and 4 respectively show network configurations of the three DC types mentioned above, namely EN-DC, NE-DC and NG-EN-DC. In addition, Secondary gNB (SgNB) in EN-DC of FIG. 2 is also called en-gNB, and Secondary eNB (SeNB) in NE-DC of FIG. 3 and Master eNB (MeNB) in NG-EN-DC of FIG. , Ng-eNB, but is referred to as gNB or eNB in ​​the present specification. In addition, the 5G System supports dual connectivity between two gNBs. Dual connectivity between two gNBs is referred to herein as NR-NR DC. FIG. 5 shows a network configuration of NR-NR DC.
[0014]
　NR is supposed to use different radio parameter sets for multiple frequency bands. Each wireless parameter set is called a "numerology". An OFDM numerology for an Orthogonal Frequency Division Multiplexing (OFDM) system is, for example, a subcarrier spacing, a system bandwidth, a Transmission Time Interval (TTI) length, a sub It includes a frame length (subframe duration), a cyclic prefix length (Cyclic prefix length), and a symbol duration (symbol duration). The 5G system includes various types of services with different service requirements such as broadband communication (enhanced Mobile Broad Band: eMBB), highly reliable and low latency communication (Ultra Reliable and Low Latency Communication: URLLC), and multi-connection M2M communication (massive). Machine Type Communication: mMTC) is included. The choice of Numerology depends on the service requirements.
[0015]
　UE and NR gNB of 5G system support aggregation of multiple NR carriers of different numerologies. In 3GPP, aggregation of multiple NR carriers (or NR cells) with different numerologies is a lower layer aggregation such as existing LTE Carrier Aggregation (CA) or a higher layer aggregation such as existing Dual Connectivity. (Upper layer aggregation) is being considered.
[0016]
　5G NR supports wider channel bandwidths (eg, 100s of MHz) than that of LTE. One channel band (ie, BW Channel ) is a radio frequency band (RF bandwidth) that supports one NR carrier. The channel band is also called the system band. LTE supports channel bands up to 20 MHz, while 5G NR supports channel bandwidths up to, for example, 500 MHz.
[0017]
　In order to efficiently support a plurality of 5G services, for example, a broadband service such as eMBB and a narrowband service such as the Internet of Things (IoT), it is preferable to be able to multiplex these services on one channel band. . Furthermore, if all 5G UEs have to support transmission and reception in the transmission bandwidth corresponding to the entire channel bandwidth, this is the low cost and low power consumption of UEs for narrowband IoT services. May interfere. Therefore, 3GPP allows one or more bandwidth parts (BWPs) to be set within the carrier band (ie, channel band or system band) of each NR component carrier. Multiple BWPs within one NR channel band may be used for frequency division multiplexing (FDM) of different numerologies (eg, subcarrier spacing (SCS)). The bandwidth part is also called the carrier bandwidth part.
[0018]
　One bandwidth part (BWP) is continuous in frequency (frequency-consecutive) and is composed of contiguous physical resource blocks (PRBs). The bandwidth of one BWP is at least as large as the synchronization signal (SS)/physical broadcast channel (PBCH) block bandwidth. The BWP may or may not include the SS/PBCH block (SSB). The BWP configuration includes, for example, numerology, frequency location, and bandwidth (eg, number of PRBs). Common PRB indexing is used for downlink (DL) BWP configuration in at least Radio Resource Control (RRC) connected state to specify the frequency location. Specifically, the offset from PRB 0 to the lowest PRB of the SSB accessed by the UE is set by higher layer signaling. The reference point "PRB 0" is common to all UEs sharing the same wideband component carrier.
[0019]
　One SS/PBCH block includes basic signals (primary signals) necessary for idle UE, such as NR synchronization signals (NR-SS) and NR physical broadcast channel (NR-PBCH). NR-SS is used by the UE to obtain DL synchronization. A Reference Signal (RS) is transmitted in the SS/PBCH block in order to enable a UE in idle to make a Radio Resource Management (RRM) measurement (eg, RSRP measurement). The RS may be the NR-SS itself or an additional RS. The NR-PBCH broadcasts a part of minimum system information (Minimum System Information (minimum SI)) (for example, Master Information Block (MIB)). The remaining minimum SI (remaining minimum SI (RMSI)) is transmitted on the Physical Downlink Shared Channel (PDSCH).
[0020]
　The network can transmit multiple SS/PBCH blocks in the channel band of one wideband component carrier. In other words, SS/PBCH blocks may be transmitted in multiple BWPs within the channel band. In the first proposal, all SS/PBCH blocks in one wideband carrier are NR-SS (eg, primary SS (PSS) and secondary SS (SSS) corresponding to the same physical-layer cell identity. ))based on. In the second alternative, different SS/PBCH blocks in one wideband carrier may be based on NR-SSs corresponding to different physical-layer cell identities.
[0021]
　From the UE perspective, a cell is associated with one SS/PBCH block. Therefore, for the UE, each serving cell has one associated SS/PBCH block in frequency. In addition, 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 SSB is called cell defining SS/PBCH block. The Cell defining SS/PBCH block has an associated RMSI. The Cell defining SS/PBCH block serves as a time reference or a timing reference of the serving cell. The Cell defining SS/PBCH block is used for SS/PBCH block (SSB) based RRM Measurements. The Cell defining SS/PBCH block is “synchronous reconfiguration” for PCell/PSCell (for example, reconfiguration of radio resource configuration information without handover using RRC Reconfiguration procedure) and for SCell “SCell release/ Can be changed by "add".
[0022]
　One or more BWP configurations for each component carrier are semi-statically signaled to the UE. Specifically, for each UE-specific serving cell, one or more DL BWPs and one or more UL BWPs can be configured for the UE by the dedicated RRC message. Moreover, one or more BWPs configured for the UE can be activated and deactivated. Activation/deactivation of BWP is determined not by the RRC layer but by lower layers (eg, Medium Access Control (MAC) layer, Physical (PHY) layer). The activated BWP is called an active BWP (active BWP).
[0023]
　Switching of the active BWP (active BWP) may be performed by, for example, downlink control information (Downlink Control Information (DCI)) (eg, scheduling DCI) transmitted by the NR Physical Downlink Control Channel (PDCCH). In other words, deactivation of the current active BWP and activation of the new active BWP may be performed by DCI of NR PDCCH. Therefore, the network can activate/deactivate the BWP depending on, for example, the data rate or the numerology required by the service and dynamically switch the active BWP for the UE. Activation/deactivation of BWP may be performed by MAC Control Element (CE).
[0024]
　6 and 7 show examples of using BWP. In the example shown in FIG. 6, the channel band of one component carrier is divided into BWP #1 and BWP #2, and these two BWPs are used for FDM with different numerologies (eg, different subcarrier spacing). . In the example shown in FIG. 7, the narrow band BWP #1 is arranged in the channel band of one component carrier, and the narrow band BWP #2 is further arranged than the BWP #1. When BWP #1 or BWP #2 is activated for a UE, the UE can reduce power consumption by not performing reception and transmission outside the active BWP (but within the channel band).
[0025]
　Non-Patent Documents 1 to 7 disclose the above-described BWP and cell defining SS/PBCH block.
[0026]
　Furthermore, 3GPP is examining the requirements of Radio Link Monitoring (RLM) related to the use of BWPs (see Non-Patent Document 8). Note that the RLM procedure uses the connected mode (ie, in order to measure the downlink radio quality of the serving cell for the purpose of detecting out of synchronization (out-of-sync) and detecting Radio Link Failure (RLF). , RRC_CONNECTED) UE.
[0027]
　Non-Patent Document 8 discloses the following items. NR supports RLM only in PCell and PSCell. The UE in the Connected mode can semi-statically set one or multiple BWPs per cell. The UE can switch the specific BWP for communication with the gNB among the set BWPs. This switching is done on a short time scale, such as some scheduling intervals. This particular BWP is the active BWP. The UE can only access one BWP at a time. The Active BWP has a Channel State Information Referrence Signal (CSI-RS) set for at least RRM. The UE is set as an RS that monitors one of the CSI-RS and SS/PBCH block (ie, NR-SS) RS type for RLM. Even if different types of RSs (ie CSI-RS and NR-SS) are configured in one BWP at the same time (simultaneously), only one RS type is selected for the RLM and is selected The parameters for RS are used for RLM. It is considered that the UE keeps the on-going L3 parameters related to the RLM when the DL active BWP is switched (or changed). In this case, even if the DL active BWP is switched, the UE does not reset the L3 parameters regarding the RLM to default values.
Prior art documents
Non-patent literature
[0028]
Non-Patent Document 1: 3GPP R1-1711795, Ericsson, “On bandwidth parts and “RF” requirements”, TSG RAN1 NR Ad-Hoc#2, Qingdao, PR China, June 2017
Non-Patent Document 2: 3GPP R2-1707624, “ LS on Bandwidth Part Operation in NR”, 3GPP TSG RAN WG2#99, Berlin, Germany, August 2017
Non-Patent Document 3: 3GPP R2-1710012, “LS on Further agreements for Bandwidth part operation”, 3GPP TSG RAN WG2 #99bis, Prague, Czech Republic, October 2017
Non-patent document 4: 3GPP R2-1710031, “Reply LS on multiple SSBs within a wideband carrier”, 3GPP TSG RAN WG2 #99bis, Prague, Czech Republic, October 2017
Non-patent document 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
Non-Patent Document 6: 3GPP R2-1711969, Ericsson, “Text Proposal for L1 parametrs for 38.331”, 3GPP TSG-RAN WG2 #99bis, Prague, Czech Republic, October 2017
Non-Patent Document 7: 3GPP R2-1709861, “LS on multiple SSBs within a wideband carrier”, 3GPP TSG RAN WG2#99, Berlin, Germany, August 2017
Non-Patent Document 8: 3GPP R2-1711404, Samsung, “RLM/RLF for bandwidth part”, 3GPP TSG RAN WG2 #99bis, Prague , Czech Republic, October 2017
Summary of the invention
Problems to be Solved by the Invention
[0029]
　As described above, in Non-Patent Document 8, only one RS is configured even when different types of RSs (that is, CSI-RS and SS/PBCH block) are simultaneously configured in one BWP. It discloses that the parameters selected for the RLM and associated with the selected RS are used for the RLM. Non-Patent Document 8 further discloses that, even if the DL active BWP is switched, the UE does not reset the L3 parameters related to the RLM to default values, as an example. However, when DL active BWP is switched, there is a problem that it is not clear which RS the UE should monitor for RLM measurement after switching. One of the objects to be achieved by the embodiments disclosed herein is to provide an apparatus, a method, and a program that contribute to solving the problem. It should be noted that this goal is only one of the goals that the embodiments disclosed herein seek to achieve. Other objects or problems and novel features will be apparent from the description of the present specification or the accompanying drawings.
Means for solving the problem
[0030]
　In a first aspect, a wireless terminal includes a memory and at least one processor coupled to the memory. Said at least one processor is a Radio Link Monitoring (RLM) if the downlink bandwidth part (BWP) is switched from the first BWP to the second BWP without modification of the cell specific synchronization signal block (SSB). If the reference signal type for is set to SSB type, then after switching the downlink BWP to the second BWP, the first SSB associated with the first BWP is used for RLM measurement. Configured for continued use.
[0031]
　In a second aspect, the method in a wireless terminal is the Radio if the downlink bandwidth part (BWP) is switched from a first BWP to a second BWP without changing the cell specific synchronization signal block (SSB). If the reference signal type for Link Monitoring (RLM) is set to SSB type, after switching the downlink BWP to the second BWP, the first SSB associated with the first BWP is switched to the first SSB. Continued use for RLM measurements.
[0032]
　In the third aspect, the program includes a group of instructions (software code) for causing the computer to perform the method according to the second aspect when read by the computer.
Effect of the invention
[0033]
　According to the above aspect, it is possible to provide an apparatus, a method, and a program that contribute to enabling the UE to monitor an appropriate RS for RLM measurement after switching the DL active BWP.
Brief description of the drawings
[0034]
FIG. 1 is a diagram showing a basic architecture of 5G System.
FIG. 2 is a diagram showing an EN-DC network configuration.
FIG. 3 is a diagram showing a network configuration of NE-DC.
FIG. 4 is a diagram showing a network configuration of NG-EN-DC.
FIG. 5 is a diagram showing a network configuration of NR-NR DC.
[Fig. 6] Fig. 6 is a diagram illustrating a usage example of a Bandwidth part (BWP).
[Fig. 7] Fig. 7 is a diagram illustrating a usage example of a Bandwidth part (BWP).
FIG. 8 is a diagram showing a setting example of BWP and SS/PBCH blocks.
FIG. 9 is a diagram showing a setting example of BWP and SS/PBCH block.
FIG. 10 is a diagram showing a configuration example of a wireless communication network according to some embodiments.
FIG. 11 is a flowchart showing an example of operation of the wireless terminal according to the first embodiment.
FIG. 12 is a flowchart showing an example of operation of the wireless terminal according to the first embodiment.
FIG. 13 is a sequence diagram showing an example of operations of a RAN node and a wireless terminal according to the first embodiment.
FIG. 14 is a flowchart showing an example of operation of the wireless terminal according to the second embodiment.
FIG. 15 is a flowchart showing an example of operation of the wireless terminal according to the second embodiment.
FIG. 16 is a sequence diagram showing an example of operations of a RAN node and a wireless terminal according to the second embodiment.
FIG. 17 is a sequence diagram showing an example of operations of a RAN node and a wireless terminal according to the third embodiment.
FIG. 18 is a block diagram showing a configuration example of a RAN node according to some embodiments.
FIG. 19 is a block diagram showing a configuration example of a wireless terminal according to some embodiments.
MODE FOR CARRYING OUT THE INVENTION
[0035]
　Hereinafter, specific embodiments will be described in detail with reference to the drawings. In each of the drawings, the same or corresponding elements are denoted by the same reference numerals, and repeated explanations will be omitted as necessary for the sake of clarity.
[0036]
　The plurality of embodiments described below may be implemented independently or may be implemented in combination as appropriate. These embodiments have novel features that are different from each other. Therefore, the plurality of embodiments contribute to solving different purposes or problems and contribute to different effects.
[0037]
　The embodiments described below are mainly described for the 3GPP 5G system. However, these embodiments may be applied to other wireless communication systems.
[0038]
　First, referring to FIGS. 8 and 9, the definition of terms relating to the case where one system band includes a plurality of BWPs will be described. 8 and 9 show setting examples of BWP and SS/PBCH blocks. In the example shown in FIGS. 8 and 9, one channel band includes three BWPs, that is, 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 SS/PBCH block.
[0039]
　From a network perspective, like the existing LTE, the entire band (ie, channel band or system band) of one component carrier corresponds to one cell. In the example of FIGS. 8 and 9, the Physical Cell Identity (PCI) associated with the cell corresponding to the channel band is “PCIx”.
[0040]
　In this specification, a cell from a network perspective is defined as a “logical cell (logcal cell)”. Furthermore, the PCI associated with the network viewpoint cell (ie, logical cell) is defined as the reference PCI. Note that the network viewpoint cell (ie, logical cell) may be associated with one Cell Identity. In this case, the Cell Identity of the network view cell (ie, logical cell) may be associated with (sub)PCIs of a plurality of physical cells described later.
[0041]
　On the other hand, as described above, in the UE perspective, a cell is associated with one SS/PBCH block. In this specification, a cell from the viewpoint of UE is defined as a "physical cell". Furthermore, the PCI associated with the UE viewpoint cell (ie, physical cell) is defined as sub PCI. That is, the plurality of BWPs included in one system band and each including the SS/PBCH block are a plurality of UE viewpoint cells (ie, a plurality of physical cells). The sub PCIs of the plurality of UE viewpoint cells (physical cells) are associated with one reference PCI or one Cell Identity of the network viewpoint cell (ie, logical cell). Furthermore, a BWP that does not include an SS/PBCH block may be defined as a UE viewpoint cell (physical cell), or a group of BWP that does not include an SS/PBCH block and a BWP that includes an SS/PBCH block that this refers to is a UE. It may be defined as a viewpoint cell (physical cell). Also from the network viewpoint, the unit system band actually used by the network (eg, RAN node) for communication with the UE is each UE viewpoint cell (physical cell).
[0042]
　In the example of FIG. 8, three BWPs support the same numerology (ie, numerology #1) and all SS/PBCH blocks (ie, SSB #1 and SSB #2) in one channel band are the same. Based on NR-SS corresponding to (sub)PCI (ie, PCIx). That is, FIG. 8 corresponds to the first scheme described above for the transmission of multiple SS/PBCH blocks in the channel band. In order for the UE to synchronize with BWP #3 that does not include SSB, SSB #1 or SSB #2 transmitted by other BWPs is referenced. At this time, the referenced SSB #1 or SSB #2 is called a reference SSB (reference SSB), and the UE may be notified of the reference SSB identifier (SSB index, eg, SSB #1 or #2) from the network. ..
[0043]
　In the example of FIG. 9, BWP #1 supports numerology #1, and BWP #2 and BWP #3 support numerology #2. Different SSBs #1 and #2 for different numerologies are based on NR-SS corresponding to different (sub)PCIs (ie, PCIx and PCIy). That is, FIG. 9 corresponds to the second scheme described above for the transmission of multiple SS/PBCH blocks in the channel band. In order for the UE to synchronize to BWP #3 that does not include SSB, for example, SSB #2 of BWP #2 that supports the same numerology as BWP #3 is referenced. Alternatively, the UE may refer to the SSB #1 of the BWP #1 that supports a different numerology from the numerology of the BWP #3, because the UE synchronizes to the BWP #3 that does not include the SSB.
[0044]
　In the example of FIG. 8, the reference PCI (ie, PCIx) or Cell Identity of one network viewpoint cell (ie, logical cell) has the sub-PCIs (ie, PCIx and PCIx) of two UE viewpoint cells (physical cells). Associated. In the example of FIG. 9, the reference PCI (ie, PCIx) or Cell Identity of one network viewpoint cell (ie, logical cell) has the sub-PCIs (ie, PCIx and PCIy) of two UE viewpoint cells (physical cells). Associated.
[0045]
　The network (eg, RAN node) may configure the UE with a BWP set including one or more BWPs. In other words, the UE receives the setting information of one or more BWPs (eg, SSB indexes, presence of SSBs, reference SSB indexes, Layer-1 parameters) from the network. The BWP set may be individually set for the downlink (DL) and the uplink (UL). That is, a BWP set may include a DL BWP set and a UL BWP set that are separate for DL ​​and UL. Alternatively, UL BWPs and DL BWPs may be associated in advance, and the BWP set in this case may be common to DL and UL. The UE can activate k (k <= K) BWPs among the K BWPs included in the (DL/UL) BWP set. In other words, up to K (DL/UL) BWP(s) can be activated at one time for a certain UE. In the following description, for simplification, it is assumed that one BWP (ie k=1) is activated. However, the present embodiment and the subsequent embodiments can be appropriately applied even when two or more (k>=2) BWPs are activated at one time.
[0046]
　In addition, this specification introduces the term "BWP group". BWP groups are included in BWP sets. The BWP group consists of one or more BWPs whose active BWP can be changed by the DCI sent on the NR PDCCH. Between one or more BWPs included in the BWP group, the active BWP can be changed without changing the Cell defining SSB. Therefore, a BWP group may be defined to be one or more BWPs associated with one cell defining SSB. A BWP group may include one BWP (eg, standard BWP, initial BWP, default BWP) that includes a cell defining SSB and one or more other BWPs. Each of the other one or more BWPs that are not the reference BWP (or initial BWP, default BWP) may or may not include SSB. The UE may explicitly specify/configure which SSB is the cell defining SSB, or implicitly that the UE is the cell defining SSB of the first BWP SSB when the relevant BWP group is configured ( implicitly).
[0047]
　The BWP group may be individually set for the downlink (DL) and the uplink (UL). That is, a BWP group may include a DL BWP group and a UL BWP group that are separate for DL ​​and UL. Alternatively, UL BWPs and DL BWPs may be associated in advance, and the BWP group in this case may be common to DL and UL.
[0048]
　In the example of FIG. 8, BWPs #1 to #3 are set in the UE as one BWP set. In the example of FIG. 8, the UE may refer to SSB #1 transmitted in BWP #1 in order to synchronize with BWP #3 (that is, in order to establish synchronization in BWP #3). In this case, BWP #1 and BWP #3 may correspond to one BWP group, and BWP #2 may correspond to another BWP group. That is, 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). Good. 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 is the cell defining SSB for the UE.
[0049]
　Also in the example of FIG. 9, BWPs #1 to #3 are set in the UE as one BWP set. In one example, BWP #1 of numerology #1 may correspond to one BWP group, and BWP #2 and BWP #3 of numerology #2 may correspond to another BWP group. That is, one BWP set (BWPs #1, #2, and #3) may include a first BWP group (BWPs #1) and a second BWP group (BWP #2 and #3). As described above, BWPs of different numerologies may be included in one BWP group. Therefore, in another example, one BWP set (BWPs #1, #2, and #3) has one BWP group (BWPs #1 and #3) and a second BWP group (BWP #2). May be included. 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 is the cell defining SSB for the UE.
[0050]
　As described above, activation/deactivation of the BWP may be performed by lower layers (eg, Medium Access Control (MAC) layer, Physical (PHY) layer) instead of the RRC layer. A timer (eg, BWP Inactivity Timer of MAC layer) may be used to activate/deactivate the DL BWP. The UE may switch the active BWP according to the timer based on the setting value transmitted by the gNB. The period (period or duration) indicated by the timer may be indicated in subframe units. For example, when the UE does not transmit or receive data in the active BWP for a predetermined period (that is, the expiration value of the timer), the active BWP of the predetermined BWP (eg, default BWP, BWP including cell defininig SSB) is changed. You may do it. The network (eg, RAN node) may also determine the active BWP change based on a similar timer.
[0051]

　FIG. 10 shows a configuration example of a wireless communication network according to some embodiments including this embodiment. In the example of FIG. 10, the wireless communication network includes a RAN node 11 and a wireless 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) (eg, gNB-CU) in a cloud RAN (C-RAN) deployment, or a Distributed Unit (DU) (eg, gNB-DU). Good. The Central Unit (CU) is also called Baseband Unit (BBU) or digital unit (DU). Distributed Unit (DU) is also called Radio Unit (RU), Remote Radio Head (RRH), Remote Radio Equipment (RRE), or Transmission and Reception Point (TRP or TRxP).
[0052]
　The UE 12 is connected to the RAN node 11 via the air interface 1001. Note that the UE 12 may be simultaneously connected to a plurality of RAN nodes for dual connectivity. The UE 12 in the Connected mod can semi-statically set one or multiple BWPs per cell. The UE 12 can switch the active BWP for communication with the RAN node 11 (eg, MgNB) or another RAN node (eg, SgNB) among a plurality of set BWPs. This switching takes place on a short time scale, for example several scheduling intervals.
[0053]
　The UE 12 executes the RLM procedure when in the connected mode (eg, NR RRC_CONNECTED). In the RLM procedure, the UE 12 performs RLM measurement. In other words, the UE 12 measures the downlink radio quality of the serving cell for the purpose of detecting out of synchronization (out-of-sync) and Radio Link Failure (RLF). For this reason, the UE 12 may be simultaneously connected to a plurality of RAN nodes in this case, in which case the UE 12 may simultaneously perform RLM in PCell and RLM in PSCell.
[0054]
　The radio quality may be, for example, RSRP, RSRQ, RSSI, or SINR, or any combination thereof. Furthermore, 5G NR employs a beam based system in which radio signals (data, control information, signaling, and RS) are beamformed. Therefore, in the measurement of cell radio quality, the UE 12 first performs measurement (ie, beam measurement) on the beam (eg, beamformed RS, pre-coded RS) of the RS transmitted in the target cell (ie, BWP), and then the RS Obtain the beam level measurement results for the beam. The measurement result for the beam of the RS is also called the radio quality of the beam. Then, the UE 12 derives the radio quality of the cell based on the measurement result of the RS beam (derive cell measurement results). In the following, when expressed as measurement for RLM (RLM measurement), measurement for RRM (RRM measurement), or simply measurement, these expressions are received from the specified RS type or RAN node from the RAN node. It means measuring or deriving at least one of the radio quality of the cell (cell quality) and the radio quality of the beam (beam quality) based on the RS setting information. The measurement of the beam quality corresponding to the RLM regarding the cell quality is called beam monitoring (BM) or beam link monitoring (BLM). Similarly, the quality deterioration of the radio link based on the beam quality corresponding to the RLF regarding the cell quality is also called beam failure.
[0055]
　In Active BWP, at least CSI-RS set for RRM is transmitted. Active BWP may or may not include SS/PBCH block (SSB). That is, the RAN node 11 may or may not transmit the NR-SS and PBCH in the active BWP. The UE 12 is designated by the RAN node 11 as an RS for which any one RS type of CSI-RS and SSB (ie, NR-SS) is measured for RLM. Even if different types of RSs (ie CSI-RS and SSB) are simultaneously transmitted in one BWP, only one RS type is selected for RLM and the selected RS type The measurement settings (measurement parameters) for are used for the RLM. The measurement settings for the selected RS type may include, for example, parameters corresponding to the thresholds "Q in " and "Q out " specified in 3GPP specifications TS 36.213 and TS 36.133 . In this case, different thresholds "Q in "and "Q out "equivalent parameters may be set for different RS types .
[0056]
　The RAN node 11 supplies the UE 12 with the RLM settings. The RLM settings include measurement settings (measurement parameters) for the RLM. The measurement settings (measurement parameters) for the RLM are, for example, a predetermined number of out-of-sync (eg N310 for PCell, N313 for PSCell), a predetermined number of in-sync (eg N311 for PCell, N314 for PSCell), And RLF timer (eg T310 for PCell, T313 for PSCell) expiration period (maximum time) is included. A predetermined number of out-of-syncs is a continuous “out-of-sync” indication received from lower layers before the UE initiates the radio link self-recovery process. The number of (indications). The predetermined number of in-syncs is the number of consecutive "in sync" indications received from the lower layers before the UE determines that the radio link has been recovered. The RLF timer is used to determine (or detect) RLF. The UE (eg, RRC layer) starts the RLF timer when it receives a certain number of consecutive out-of-sync (OOS) indications from lower layers, and if it receives a certain number of consecutive in-sync (IS) indications. Then stop the RLF timer. The expiration period (maximum time) of the RLF timer corresponds to the maximum time allowed for the recovery of the radio link dynamically performed by the UE. In response to the expiration of the RLF timer, the UE detects the RLF.
[0057]
　In the RLM procedure, the UE 12 may assess the radio link quality for each radio frame. In this case, the UE 12 may select the type of RS (eg CSI-RS or SS/PBCH block) used for RLM for each radio frame for assessing the radio link quality. Also, the UE 12 may select the RS type used for evaluation of radio link quality and RLM for each subframe, each slot, each OFDM symbol, or each TTI instead of each radio frame.
[0058]
　When the DL active BWP is changed from the first BWP to the second BWP without changing the Cell defining SSB, the UE 12 behaves as follows regarding the RLM measurement. If the RS type for the RLM of the first BWP received by the UE 12 is set to the SSB type (ie NR-SS), the UE 12 will continue to use the DL BWP after switching to the second BWP. , Continues to monitor the first SSB associated with the first BWP for RLM measurements. In other words, even if the second BWP includes SSB, when the UE 12 is instructed to measure SSB-based RLM, the UE 12 uses the SSB in the second BWP for measurement for RLM. do not do. At this time, the UE 12 may not measure the SSB in the second BWP or may measure it for RRM. It should be noted that the timing indicated by the expression "when changed" here and thereafter may be the timing of the radio frame level, or the timing of the subframe, slot, or OFDM symbol level. ..
[0059]
　The first SSB may be a cell defining SSB associated with the first BWP. The first SSB may be included in the first BWP or may be included in another BWP.
[0060]
　The UE 12 may continue to use the measurement setting (eg, Measurement Object) for the RLM before switching the active BWP in order to continue to use the first SSB for the RLM measurement. Further, the UE 12 may take over and use the value (or status) of the RLM-related parameter before switching the active BWP. In other words, the UE 12 may continue to measure the first SSB for the RLM based on the measurement settings and parameters (states) for the RLM before switching the active BWP. In other words, the UE 12 may consider (may be considered) that the measurement settings and parameters (states) for the RLM before the switching of the active BWP are used after the switching of the active BWP.
[0061]
　The RLM-related parameters include, for example, the count value of continuous out-of-sync display, the count value of continuous in-sync display, and the value of RLF timer. The RLM related parameters may include an in-sync threshold and an out-of-sync threshold. The UE 12 compares the estimated DL radio link quality with in-sync and out-of-sync thresholds for radio link monitoring (RLM). Each of the in-sync threshold value and the out-of-sync threshold value is, for example, an RSRP threshold value, and is expressed in terms of Block Error Rate (BLER) of a hypothetical PDCCH transmission from the serving cell. Specifically, for example, the out-of-sync threshold corresponds to 10% BLER of a hypothetical PDCCH transmission that considers transmission parameters for out-of-sync and Physical Control Format Indicator Channel (PCFICH) errors. Defined as a level. On the other hand, the in-sync threshold value is defined as a level corresponding to 2% BLER of a hypothetical PDCCH transmission in consideration of transmission parameter for in-sync and Physical Control Format Indicator Channel (PCFICH) error, for example.
[0062]
　As described above, the measurement settings for the RLM may include, for example, a predetermined number of out-of-syncs, a predetermined number of in-syncs, and an expiration period (maximum time) of the RLF timer. Furthermore, the measurement settings for RLM may include PDCCH/PCFICH transmission parameters for out-of-sync and PDCCH/PCFICH transmission parameters for in-sync. PDCCH/PCFICH transmission parameters are, for example, DCI format, number of control OFDM symbols, Aggregation level, ratio of PDCCH RE energy to average RS Resource Element (RE) energy (Ratio), and PCFICH to average RS Resource Element (RE) energy. The RE energy ratio (Ratio) may be included. Note that RS RE energy, PDCCH RE energy, and PCFICH RE energy indicate the energy of RS, PDCCH, and PCFICH per RE, respectively. These PDCCH/PCFICH transmission parameters may be set for each BWP, for each SSB, or for each CSI-RS. Further or alternatively, these PDCCH/PCFICH transmission parameters may be set/used for each radio frame, each subframe, each slot, each OFDM symbol, or each TTI.
[0063]
　FIG. 11 is a flowchart showing an example (process 1100) of the RLM-related operation performed by the UE 12. In step 1101, the UE 12 receives from the RAN node 11 an instruction to switch the DL active BWP from the first BWP to the second BWP without changing the Cell defining SSB. The instruction may, for example, indicate activation of the second BWP and further indicate deactivation of the first BWP. As described above, activation/deactivation of BWP is performed by, for example, DCI (eg, scheduling DCI) transmitted in NR PDCCH.
[0064]
　In step 1102, the UE 12 determines which RS type is used for the RLM of the first BWP before the DL active BWP switch. If the UE 12 is configured for SSB based RLM measurement, the UE 12 continues the RLM measurement on the first SSB associated with the first BWP after switching the DL active BWP to the second BWP. To do. In other words, if the RS type for the RLM of the first BWP received by the UE 12 is set to the SSB type (ie NR-SS), the UE 12 sends the first SSB associated with the first BWP. Continue to make measurements for RLM. Further, the UE 12 may use the measurement and the measurement result as the measurement and the measurement result of the adjacent cell (or adjacent BWP) for RRM.
[0065]
　As can be understood from the above description, the UE 12 has the DL active BWP of the first without the cell defining SSB change if the UE 12 has the SSB based RLM measurement configured for the first BWP. When the BWP is changed to the second BWP, it operates as follows. In other words, the UE 12 determines that if the RS type of the RLM measurement for the first BWP received by the UE 12 is set to SSB (ie NR-SS), the DL active BWP is set to the first by the NR PDCCH/DCI. When the BWP is switched to the second BWP, it operates as follows. That is, the UE 12 continues to perform the measurement for the first SSB associated with the first BWP for the RLM even after switching the DL BWP to the second BWP. The first SSB may be a cell defining SSB associated with the first BWP. The first SSB may be included in the first BWP or may be included in another BWP. As a result, the UE 12 can continue the RLM based on the same first SSB as that before the DL active BWP switching, even after the DL active BWP switching.
[0066]
　Since the RS (eg, first SSB) used for RLM measurement is not changed before and after the DL active BWP switching without changing the Cell defining SSB, the UE 12 can continuously measure the radio quality of the cell. it can. For example, the UE 12 can stably measure the radio quality of the cell even when the active BWP is dynamically switched in the BWP group, and can appropriately grasp (detect) the deterioration or improvement of the radio quality. .. Therefore, the control method is particularly effective for the operation in which the active BWP is switched at a relatively short time interval (interval).
[0067]
　On the other hand, if the UE 12 is configured for CSI-RS based RLM measurement, the UE 12 may change the DL active BWP from the first BWP to the second BWP without changing the Cell defining SSB. You may operate as follows. In other words, if the RS type for the RLM received by the UE 12 is set to CSI-RS, the UE 12 will change the DL active BWP from the first BWP to the second BWP by the NR PDCCH/DCI. May operate as follows. That is, the UE 12 may perform the RLM measurement on the second CSI-RS in the second BWP instead of the first CSI-RS in the first BWP. Although the UE 12 changes the CSI-RS used for RLM, it may take over the value (or status) of the RLM-related parameter before switching the active BWP and use it. The RLM related parameters may include a count value for continuous out-of-sync indications, a count value for consecutive in-sync indications, and a value for the RLF timer, as described above. The RLM related parameters may include an in-sync threshold and an out-of-sync threshold. Furthermore, although the UE 12 changes the CSI-RS used for the RLM, it may take over and use at least a part of the measurement settings for the RLM before switching the active BWP. The measurement settings for the RLM may include the predetermined number of out-of-syncs, the predetermined number of in-syncs, and the expiration period (maximum time) of the RLF timer, as described above. Furthermore, the measurement settings for RLM may include PDCCH/PCFICH transmission parameters.
[0068]
　FIG. 12 is a flowchart showing another example (process 1200) of the operation related to RLM performed by the UE 12. The process in step 1201 is the same as the process in step 1101. In step 1202, the UE 12 determines which RS type is used for the RLM of the first BWP before switching the DL active BWP. If the UE 12 is configured for CSI-RS based RLM measurement, the UE 12 will switch to the second CWP in the first BWP instead of the second CSI-RS in the first BWP after switching the DL active BWP to the second BWP. Use the second CSI-RS in the BWP for RLM measurements. That is, the UE 12 performs the RLM measurement on the second CSI-RS.
[0069]
　When the DL active BWP switching is performed, by changing the RS (eg, CSI-RS) used for the RLM to the RS transmitted in the DL active BWP after the switching, the UE 12 causes the stay cell (active cell) (active RLM based on BWP) radio quality. For example, when the active BWP is switched to semi-static (semi-static) in the BWP group, the UE 12 can appropriately measure the radio quality of the cell actually used, and the deterioration or improvement of the radio quality. Can be appropriately grasped (detected). Therefore, the control method is particularly effective for the operation in which the active BWP is switched at a relatively long time interval (interval).
[0070]
　As can be understood from the above description, in some implementations, the UE 12 may perform the following when the DL active BWP is changed from the first BWP to the second BWP without changing the Cell defining SSB. May work. That is, the UE 12 is monitored for the RLM after switching the DL active BWP depending on whether the SSB based RLM measurement is set for the first BWP or the CSI-RS based RLM measurement is set. Determine whether to change the reference signal (RS). In other words, whether the UE 12 changes the RS used for RLM measurement after DL active BWP switching depending on whether the RS type for RLM is SSB type or CSI-RS type. To decide. As a result, when the UE 12 receives an instruction (DCI) to switch the DL active BWP in the BWP group on the NR PDCCH, the UE 12 is appropriately used for RLM measurement without receiving the RRC message (eg, RRC Reconfiguration). RS can be changed. In other words, the RAN node 11 can cause the UE 12 to select the RS used for the RLM measurement only by transmitting the NR PDCCH without transmitting the RRC message. That is, it is expected to reduce the amount of radio signals (RRC signaling) and the delay in changing the setting of the RRC layer in the UE 12.
[0071]
　FIG. 13 is a sequence diagram showing an example (process 1300) of operations of the RAN node 11 and the UE 12 according to the present embodiment. The UE RRC layer 121 and the UE MAC layer 122 are included in the control plane protocol stack of the UE 12. The UE RRC layer 121 is a lower layer of the UE NAS layer (not shown), provides radio resource control (RRC), and manages the RRC state (eg, NR RRC_IDLE and NR RRC_CONNECTED) of the UE 12. The RRC state indicates, for example, whether or not a wireless connection (RRC connection) between the UE 12 and the RAN node 11 has been established.
[0072]
　The UE RRC layer 121 receives from the RAN node 11 one or more BWP configurations for each component carrier. The RAN node 11 transmits one or a plurality of BWP related control information (BWP configurations) for each component carrier to the UE RRC layer 121 using, for example, an RRC Reconfiguration message. One or more BWP configurations for each component carrier may include, for example, at least one Information Element (IE) of the following:
one or more associated with one or more downlink BWPs Information element indicating the above BWP index;
-Information element indicating one or more BWP indexes associated with one or more uplink BWPs ; -Carrier
frequency (eg, Absolute Radio Frequency Channel) associated with each BWP Information element indicating Number (ARFCN);
- Information element indicating whether or not each BWP includes SS/PBCH block (SSB);
-Reference SSB associated with BWP that does not include SSB or reference SSB is included Information element that indicates the reference BWP to be used;
-Information element that indicates the configuration of the SSB transmitted by each BWP (eg, SS series or PCI, SSB duration, numerical)-Reference
PRB (eg, PRB0) to lowest PRB of each SSB Information element indicating the offset of
An information element indicating the numerology set for each BWP; and
an information element indicating the configuration of a BWP set or BWP group (eg, information on the index of each BWP group and the list of BWP indexes included in it).
[0073]
　Furthermore, the UE RRC layer 121 receives the measurement configuration (MeasConfig) for RLM of each serving cell from the RAN node 11. The RAN node 11 transmits the measurement configuration for RLM of each serving cell to the UE RRC layer 121 using, for example, an RRC Reconfiguration message. The measurement settings include the measurement settings for RLM (eg, RS type).
[0074]
　Furthermore, the measurement settings for RLM of each serving cell may include the measurement settings for RLM described above. The measurement configuration (measurement parameter set) for one or more RLMs may be included in the corresponding one or more BWP configurations. Alternatively, the measurement configuration for RLM of each serving cell may be included in DCI or MAC CE transmitted on NR PDCCH.
[0075]
　The UE MAC layer 122 determines activation/deactivation of one or more BWPs set in the UE 12. As described above, switching of BWPs within a BWP group is performed by, for example, DCI transmitted on NR PDCCH. Further, at this time, the inactivation of the active BWP before the switching and the activation of the active BWP after the switching may be performed by the DCI.
[0076]
　In step 1301, the RAN node 11 transmits DCI for DL ​​active BWP switching to the UE 12 on the NR PDCCH. The DCI triggers the UE 12 to switch the DL active BWP. In step 1302, the UE MAC layer 122 switches the DL active BWP in response to receiving the DCI from the RAN node 11. In step 1303, the UE MAC layer 122 notifies the UE RRC layer 121 of DL active BWP switching. The notification of step 1303 may be given before step 1302.
[0077]
　In step 1304, the UE RRC layer 121 determines the RS type applied to the DL active BWP before switching in response to receiving the notification indicating the switching of the DL active BWP from the lower layer (MAC layer 122). To do. In other words, the UE RRC layer 121 determines whether the RS type used for RLM is the SSB type or the CSI-RS type.
[0078]
　In step 1305, the UE RRC layer 121 modifies the RLM measurement depending on whether the RS type for the RLM applied to the DL active BWP before switching is the SSB type or the CSI-RS type. Specifically, if the RS type for the RLM that was applied to the DL active BWP before switching is the SSB type, the UE RRC layer 121 is used for the RLM measurement after switching the DL active BWP. Do not change the signal (ie, SSB). That is, the UE RRC layer 121 continues to perform RLM based on the same SSB. On the other hand, if the RS type for the RLM applied to the DL active BWP before switching is the CSI-RS type, the UE RRC layer 121 determines the RLM based on the CSI-RS included in the DL active BWP after switching. To execute.
[0079]
　In addition, in the present embodiment, the UE 12 may perform the CSI measurement in addition to the RLM measurement. The CSI measurement means that when the UE 12 is in the connected mode (eg, NR RRC_CONNECTED), it sends a report including the Channel Quality Indicator (CQI) used for at least one of scheduling and link adaptation to the RAN node 11. It includes measuring the DL radio quality of the serving cell as the purpose. When the DL active BWP is switched from the first BWP to the second BWP without changing the cell defining SSB, the UE 12 replaces the first CSI-RS in the first BWP with the second BWP. The second CSI-RS of may be monitored for CSI measurements.
[0080]
　Also, in the above description, an example has been shown in which the UE MAC layer 122 notifies the UE RRC layer 121 of DL active BWP switching in response to receiving the DCI for DL ​​active BWP switching on the NR PDCCH. However, instead of the UE MAC layer 122, the UE PHY layer that receives the DCI may directly send the notification to the UE RRC layer 121 (and the UE MAC layer 122).
[0081]
Second Embodiment
　This embodiment provides an example of UE RLM measurement when the DL active BWP is switched with the change of the cell defining SSB. A configuration example of the wireless communication network according to this embodiment is the same as the example shown in FIG.
[0082]
　In the present embodiment, when the DL active BWP is changed from the first BWP to the second BWP with the change of Cell defining SSB, the UE 12 behaves as follows regarding RLM measurement. If the RS type for the RLM of the first BWP is set to the SSB type, the UE 12 may use the first SSB associated with the first BWP for the RLM measurement. Stop (or suspend). That is, the UE 12 suspends (or suspends) the RLM based on the first SSB. Additionally or alternatively, if the RS type for the RLM of the first BWP is set to the SSB type, the UE 12 may use the second SSB instead of the first SSB associated with the first BWP. A second SSB associated with the BWP may be used for RLM measurements.
[0083]
　When stopping (or suspending) using the first SSB associated with the first BWP for the RLM measurement, the UE 12 determines the value (or state) of the RLM-related parameter before switching the DL active BWP. ) May be reset to the default value (eg, zero) or set value (eg, expiry value). The RLM related parameters may include a continuous out-of-sync display count value, a continuous in-sync display count value, and an RLF timer value.
[0084]
　When the SSB is used for the RLM as in this embodiment, the DL radio qualities may be significantly different between a plurality of physical cells (BWPs) having different cell defining SSBs in one logical cell. .. For example, when multiple physical cells (BWPs) with different cell defining SSBs are used in one logical cell, the bandwidth of one logical cell is large (eg, 400 MHz), so the physical cells (BWPs) are There is a possibility that the frequency characteristics will differ greatly. Alternatively, by applying different numerology (eg, Subcarrier spacing) to a plurality of physical cells (BWPs), the radio propagation characteristics may be greatly different between the physical cells (BWPs). In other words, the reception qualities of the two cell defininig SSBs at the UE 12 before and after the switching of the DL active BWP may be significantly different. Therefore, if the UE 12 does not change the SSB used for the RLM before and after the switching of the DL active BWP accompanied by the change of the cell defininig SSB, it is expected that the RLM after the switching of the DL active BWP will not be optimal. Therefore, the UE 12 operates as described above to optimize the RLM after switching the DL active BWP.
[0085]
　Alternatively, when the SSB monitoring for the RLM measurement is stopped (or interrupted), the UE 12 resets the value (or state) of the RLM related parameters before switching the DL active BWP. Instead, it may be maintained (retained). Then, the UE 12 may start the RLM measurement in the second SSB associated with the second BWP after switching using the value of the RLM-related parameter that has been maintained (held). This is effective when the frequency characteristics and propagation characteristics of the DL active BWPs before and after switching are the same or similar even if the cell defining SSB is changed. Therefore, the RAN node 11 determines whether or not the value of the RLM-related parameter is reset (or the value (or state) of the RLM-related parameter is maintained in the switching of the DL active BWP accompanied by the change of the cell defining SSB. May be transmitted to the UE 12. The information may be transmitted from the RAN node 11 to the UE 12 together with an instruction to switch the DL active BWP.
[0086]
　FIG. 14 is a flowchart showing an example of the RLM-related operation (process 1400) performed by the UE 12. In step 1401, the UE 12 receives from the RAN node 11 an instruction to switch the DL active BWP from the first BWP to the second BWP with the change of Cell defining SSB. The instruction may, for example, indicate activation of the second BWP and further indicate deactivation of the first BWP. Since the Cell defining SSB is changed, the instruction may be sent from the RAN node 11 to the UE 12 by RRC signaling (eg, RRC Reconfiguration message).
[0087]
　In step 1402, if the UE 12 is configured for SSB based RLM measurement, the UE 12 aborts the first SSB based RLM associated with the first BWP. In step 1403, the UE 12 resets the value (or state) of the RLM-related parameter before switching the DL active BWP to the default value (eg, zero) or the set value (eg, expiration value). Step 1403 may not be performed.
[0088]
　FIG. 15 is a flowchart showing another example (process 1500) of the RLM-related operation performed by the UE 12. The processing performed in steps 1501 to 1503 is the same as the processing performed in steps 1401 to 1403.
[0089]
　In step 1504, if the UE 12 is configured for SSB based RLM measurement, the UE 12 is based on the second SSB associated with the second BWP instead of the first SSB associated with the first BWP. Start RLM.
[0090]
　On the other hand, if the RS type for the RLM is set to the CSI-RS type, the UE 12 may change the DL active BWP from the first BWP to the second regardless of whether or not the Cell defining SSB is changed. When changing to BWP, it may operate as follows. That is, the UE 12 may use the second CSI-RS in the second BWP instead of the first CSI-RS in the first BWP for the RLM measurement. Although the UE 12 changes the CSI-RS used for RLM, the UE 12 may continue to use the value (or status) of the RLM-related parameter before switching the active BWP. The RLM related parameters may include a count value for continuous out-of-sync indications, a count value for consecutive in-sync indications, and a value for the RLF timer, as described above. The RLM related parameters may include an in-sync threshold and an out-of-sync threshold.
[0091]
　FIG. 16 is a sequence diagram showing an example (process 1600) of operations of the RAN node 11 and the UE 12 according to the present embodiment. The UE RRC layer 121 and the UE MAC layer 122 are included in the control plane protocol stack of the UE 12.
[0092]
　In step 1601, the RAN node 11 transmits an RRC Reconfiguration message for BWP reconfiguration to the UE 12 (UE RRC layer 121). The BWP reconfiguration triggers the UE 12 to change the cell defining SSB and switch the DL active BWP.
[0093]
　In step 1602, the UE RRC layer 121 instructs the UE MAC layer 122 to switch the DL active BWP. In step 1603, the UE MAC layer 122 switches the DL active BWP according to the instruction from the UE RRC layer 121. At this time, the UE RRC layer 121 or the UE MAC layer 122 gives an instruction to switch the DL active BWP to the UE PHY layer (not shown), and the UE PHY layer switches the radio processing unit (eg, RF) according to the instruction. It may be adjusted to correspond to DL active BWP.
[0094]
　In step 1604, the RLM measurement is modified depending on the change of cell defining SSB and the switching of DL active BWP. Specifically, if the RS type for the RLM applied to the DL active BWP before switching is the SSB type (ie, NR-SS), the UE RRC layer 121 associates with the DL active BWP before switching. The SSB associated with the switched BWP is used for the RLM measurement instead of the assigned SSB. On the other hand, if the RS type for the RLM applied to the DL active BWP before switching is the CSI-RS type, the UE RRC layer 121 measures the CSI-RS included in the DL active BWP after switching by RLM. To use for.
[0095]
　Note that the UE 12 of the present embodiment may further perform the RLM-related operation of the UE when the DL active BWP is switched without changing the cell defining SSB described in the first embodiment. In other words, the UE 12 depends on whether the switching of the (DL) active BWP from the first BWP to the second BWP is accompanied by a change of the cell defining SSB and the first BWP associated with the first BWP. It may be determined whether or not the SSB of will continue to be used for the RLM measurement. As a result, the UE 12 includes not only the radio quality in the (DL) BWP corresponding to the physical cell (serving cell) to stay, but also the cell defining SSB (the SSB is transmitted) in the (DL) BWP. Can be appropriately understood. As described above, the DL BWP including the Cell defining SSB is a DL BWP that represents one of one or more physical cells included in the logical cell. Therefore, by grasping the radio quality of the (DL) BWP including the Cell defining SSB, the UE 12 can contribute to appropriately determining whether or not the UE 12 stays in the physical cell. In addition, the (DL) BWP including the Cell defining SSB includes all the BWPs included in the same logical cell if the (DL) BWP including the Cell defining SSB is not in the same logical cell (not set). It can also be considered the representative (DL) BWP. Therefore, by grasping the radio quality of the (DL) BWP including the Cell defining SSB, the UE 12 can contribute to appropriately determining whether or not it is appropriate for the UE 12 to stay in the logical cell.
[0096]
　Furthermore, also in this embodiment, the UE 12 may perform the CSI measurement in addition to the RLM measurement. When the DL active BWP is switched from the first BWP to the second BWP with the change of cell defining SSB, the UE 12 replaces the first CSI-RS in the first BWP with the second BWP in the second BWP. The second CSI-RS may be monitored for CSI measurement.
[0097]
The
　present embodiment provides a method of measurement setting for coping with switching of active BWPs among a plurality of BWPs included in one BWP group. A configuration example of the wireless communication network according to this embodiment is the same as the example shown in FIG. The measurement setting method described in the present embodiment can be used for setting the RLM measurement, the RRM measurement, and the CSI measurement in the above-described first and second embodiments.
[0098]
　In this embodiment, the RAN node 11 handles a serving cell (serving BWP) in order to handle switching of active BWPs (without changing cell defining SSB) among a plurality of DL BWPs included in one DL BWP group. , Active BWP) and neighboring cells (non-serving BWP, neighboring BWP) can be exchanged (swap) with measurement settings provided to the UE 12 in advance by RRC signaling (eg, RRC Reconfiguration message). UE12 responds to switching of active BWP for communication between UE12 and RAN between BWPs in a BWP group, and the measurement setting previously received is served to a serving cell (serving BWP, active BWP) and an adjacent cell ( Non-serving BWP, adjacent BWP) exchange and use.
[0099]
　For example, when one BWP group includes first and second BWPs, in the RAN node 11, the first BWP is a serving cell (serving BWP) and the second BWP is an adjacent cell (adjacent BWP, non-serving BWP). The measurement configuration corresponding to the situation is supplied to the UE 12 by RRC signaling (eg, RRC Reconfiguration message). The UE 12 executes measurement (eg, RLM measurement, RRM measurement, CSI measurement) according to the measurement setting when the active BWP is the first BWP. In addition, the UE 12 responds to the switching of the active BWP from the first BWP to the second BWP, and the serving cell (serving BWP) and the adjacent cell (neighboring BWP, non-serving BWP) of the measurement setting that have already been received. Exchange and use the relationship.
[0100]
　The RAN node 11 and the UE 12 of this embodiment do not require RRC signaling for updating measurement settings when switching active BWPs within a BWP group. Therefore, the RAN node 11 and the UE 12 of the present embodiment can promptly update the measurement setting in response to the switching of the active BWP in the BWP group, and follow the measurement setting corresponding to the active BWP after the switching. The measurement operation can be started quickly.
[0101]
　FIG. 17 is a sequence diagram showing an example of an operation (process 1700) of the RAN node 11 and the UE 12 according to this embodiment. Here, the BWP group consists of BWP #1 with SSB and BWP #2 without SSB, and UE12 first camps on BWP #1 (ie BWP #1 is the active BWP). Assumption.
[0102]
　In step 1701, the RAN node 11 sends an RRC Reconfiguration message to the UE 12. The RRC Reconfiguration message includes measurement settings corresponding to a situation in which BWP #1 is a serving cell (serving BWP) and BWP #2 is an adjacent cell (adjacent BWP).
[0103]
　The UE 12 uses the measurement settings received in step 1701 to perform measurement on BWP #1 (eg, RLM measurement, CSI measurement, RRM measurement) and measurement on adjacent cells including BWP #2 (eg, RRM measurement). Is executed (step 1702).
[0104]
　In step 1703, the RAN node 11 transmits, to the UE 12, control information indicating switching of active BWP from BWP #1 to BWP #2, that is, DCI on the NR PDCCH. The UE 12 switches the active BWP to BWP #2 in response to the reception of the control information (PDCCH/DCI). Further, in accordance with the switching of the active BWP, the UE 12 establishes the relationship between the serving cell (serving BWP, active BWP) and the adjacent cell (non-serving BWP, adjacent BWP) with the measurement settings received (that is, held) in advance. They are exchanged for use (step 1704). In other words, the UE 12 regards the serving cell (serving BWP) in the measurement setting that is already held as BWP #2, and performs the measurement according to at least a part of the measurement setting. Alternatively, the UE 12 assumes that the BWP #2 is the serving cell (serving BWP) and the BWP #1 is the adjacent cell (adjacent BWP), and performs the measurement according to at least a part of the measurement settings already held. May be.
[0105]
　The measurements of step 1704 may include SSB-based measurements and CSI-RS based measurements. If UE 12 is configured for SSB-based measurements, UE 12 may monitor SSB in BWP #1 for RLM measurements. In this case, the UE 12 may take over the setting related to the SSB-based measurement among the measurement settings corresponding to the BWP #1 for the SSB-based measurement after switching the active BWP from the BWP #1 to the BWP #2. In other words, the UE 12 has the serving cell (serving BWP) in the measurement setting that has been previously received (that is, already held) for the CSI-RS based measurement after switching the active BWP from BWP #1 to BWP #2. May be considered to be BWP #2. Alternatively, the UE 12 assumes that the BWP #2 is the serving cell (serving BWP) and the BWP #1 is the adjacent cell (adjacent BWP), and performs the measurement according to at least a part of the measurement settings already held. May be.
[0106]
　Additionally or alternatively, except for the measurement settings specific to BWP #1 and BWP #2, the measurement settings for the carrier frequency (measObject) may be the same measurement before and after switching the active BWP.
[0107]
　Additionally or alternatively, the RAN node 11 may transmit the “s-measure” setting to the UE in advance in the measurement setting. It should be noted that s-measure is an RSRP threshold value and is used to determine the measurement start of the adjacent cell. When the RSRP of the serving cell falls below s-measure, the UE 12 starts measuring the adjacent cell. Further, the UE 12 may be able to select the target of s-measure from SSB (ie ssb-rsrp) and CSI-RS (ie csi-rsrp). In this case, the RAN node 11 sends the UE 12 s-measure to SSB. It may be specified whether it is -based or CSI-RS based. UE12 determines the s-measure after switching the active BWP from BWP #1 to BWP #2 by measuring the measured value (eg, SSB-based RSRP or CSI-RS) for the serving BWP (ie, BWP #2) after switching. based RSRP). Instead of this, the UE 12 may determine the s-measure using the measurement value for the serving BWP (ie, BWP #1) before switching.
[0108]
　The RAN node 11 handles the s-measure after switching the active BWP (that is, which of the measured value for the active BWP before switching and the measured value for the active BWP after switching is used for the determination of s-measure after switching the active BWP). ) May be notified to the UE 12 in advance. The RAN node 11 may specify the handling of s-measure after switching the active BWP in the measurement setting or the setting information of the BWP set. Instead of this, the UE 12 is subject to s-measure after switching the active BWP according to the setting of the RS type (eg, SSB or CSI-RS) subject to the s-measure before switching the active BWP. You may decide the type. For example, when the RS type that is the target of the s-measure before switching the active BWP is SSB, the UE 12 may use the measurement value for the SSB to determine the s-measure after switching the active BWP. At this time, the UE 12 may perform measurement on the SSB in the active BWP before switching if the active BWP after switching does not include SSB, or after switching if the active BWP after switching includes SSB. Measurements may be performed on the SSB in the active BWP of.
[0109]
　For example, when the s-measure of the measurement setting defines the RSRP threshold of RS (eg, NR-SS) in SSB, the RAN node 11 uses the s-measure used after switching the active BWP in the BWP group in step 1701. The UE 12 may be notified in advance. For example, if the new active BWP (eg, active BWP #2) after switching the active BWP in the BWP group does not include SSB, the RAN node 11 uses the CSI-RS for the s-measure after switching the active BWP. The RSRP threshold of may be preset. Alternatively, if s-measure of the measurement setting defines the RSRP threshold of CSI-RS (and the CSI-RS setting in BWP #2 is sent from RAN node 11 to UE 12), UE12 After switching the active BWP from #1 to BWP #2, you may continue to use the s-measure settings before switching.
[0110]
　Subsequently, hereinafter, configuration examples of the RAN node 11 and the UE 12 according to the above-described embodiments will be described. FIG. 18 is a block diagram showing a configuration example of the RAN node 11 according to the above embodiment. Referring to FIG. 18, the RAN node 11 includes a Radio Frequency transceiver 1801, a network interface 1803, a processor 1804, and a memory 1805. The RF transceiver 1801 performs analog RF signal processing to communicate with NG UEs including the UE 12. The RF transceiver 1801 may include multiple transceivers. The RF transceiver 1801 is coupled with the antenna array 1802 and the processor 1804. The RF transceiver 1801 receives the modulation symbol data from the processor 1804, generates a transmission RF signal, and supplies the transmission RF signal to the antenna array 1802. The RF transceiver 1801 also generates a baseband received signal based on the received RF signal received by the antenna array 1802, and supplies this to the processor 1804. The RF transceiver 1801 may include an analog beamformer circuit for beamforming. The analog beamformer circuit includes, for example, a plurality of phase shifters and a plurality of power amplifiers.
[0111]
　The network interface 1803 is used to communicate with network nodes (eg, NG Core control node and transfer node). The network interface 1803 may include, for example, a network interface card (NIC) compliant with IEEE 802.3 series.
[0112]
　The processor 1804 performs digital baseband signal processing (data plane processing) and control plane processing for wireless communication. Processor 1804 may include multiple processors. For example, the processor 1804 includes a modem processor (eg, Digital Signal Processor (DSP)) that performs digital baseband signal processing and a protocol stack processor (eg, Central Processing Unit (CPU)) or Micro Processing Unit (CPU) that performs control plane processing. MPU)) may be included. Processor 1804 may include a digital beamformer module for beamforming. The digital beamformer module may include a Multiple Input Multiple Output (MIMO) encoder and precoder.
[0113]
　The memory 1805 is composed of a combination of a volatile memory and a non-volatile memory. The volatile memory is, for example, Static Random Access Memory (SRAM) or Dynamic RAM (DRAM), or a combination thereof. The non-volatile memory is a mask Read Only Memory (MROM), Electrically Erasable Programmable ROM (EEPROM), flash memory, hard disk drive, or any combination thereof. Memory 1805 may include storage located remotely from processor 1804. In this case, the processor 1804 may access the memory 1805 via the network interface 1803 or an I/O interface (not shown).
[0114]
　The memory 1805 may store one or more software modules (computer programs) 1806 including an instruction group and data for performing processing by the RAN node 11 described in the above-described embodiments. In some implementations, the processor 1804 may be configured to perform the processing of the RAN node 11 described in the above embodiments by reading the software module 1806 from the memory 1805 and executing it.
[0115]
　When the RAN node 11 is the gNB-CU, the RAN node 11 does not have to include the RF transceiver 1801 (and the antenna array 1802).
[0116]
　FIG. 19 is a block diagram showing a configuration example of the UE 12. The Radio Frequency (RF) transceiver 1901 performs analog RF signal processing for communicating with the RAN node 11. The RF transceiver 1901 may include multiple transceivers. The analog RF signal processing performed by the RF transceiver 1901 includes frequency up conversion, frequency down conversion, and amplification. The RF transceiver 1901 is coupled with the antenna array 1902 and the baseband processor 1903. The RF transceiver 1901 receives modulated symbol data (or OFDM symbol data) from the baseband processor 1903, generates a transmission RF signal, and supplies the transmission RF signal to the antenna array 1902. The RF transceiver 1901 also generates a baseband reception signal based on the reception RF signal received by the antenna array 1902, and supplies this to the baseband processor 1903. The RF transceiver 1901 may include an analog beamformer circuit for beamforming. The analog beamformer circuit includes, for example, a plurality of phase shifters and a plurality of power amplifiers.
[0117]
　The baseband processor 1903 performs digital baseband signal processing (data plane processing) and control plane processing for wireless communication. Digital baseband signal processing includes (a) data compression/decompression, (b) data segmentation/concatenation, (c) transmission format (transmission frame) generation/decomposition, and (d) transmission channel coding/decoding. , (E) modulation (symbol mapping)/demodulation, and (f) generation of OFDM symbol data (baseband OFDM signal) by Inverse Fast Fourier Transform (IFFT). On the other hand, the control plane processing includes layer 1 (eg, transmission power control), layer 2 (eg, radio resource management, and hybrid automatic repeat request (HARQ) processing), and layer 3 (eg, attach, mobility, and call management). Signaling management).
[0118]
　For example, the digital baseband signal processing performed by the baseband processor 1903 includes signal processing of Service Data Adaptation Protocol (SDAP) layer, Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer, MAC layer, and PHY layer. May be included. Further, the control plane processing by the baseband processor 1903 may include processing of Non-Access Stratum (NAS) protocol, RRC protocol, and MAC CE.
[0119]
　The baseband processor 1903 may perform MIMO encoding and precoding for beamforming.
[0120]
　The baseband processor 1903 may include a modem processor (eg, DSP) that performs digital baseband signal processing and a protocol stack processor (eg, CPU or MPU) that performs control plane processing. In this case, the protocol stack processor that performs the control plane process may be shared with the application processor 1904 described later.
[0121]
　The application processor 1904 is also called a CPU, MPU, microprocessor, or processor core. The application processor 1904 may include a plurality of processors (a plurality of processor cores). The application processor 1904 is a system software program (Operating System (OS)) read from the memory 1906 or a memory (not shown) and various application programs (for example, call application, WEB browser, mailer, camera operation application, music playback). Various functions of the UE 12 are realized by executing an application.
[0122]
　In some implementations, the baseband processor 1903 and the application processor 1904 may be integrated on a single chip, as indicated by the dashed line (1905) in FIG. In other words, the baseband processor 1903 and the application processor 1904 may be implemented as one System on Chip (SoC) device 1905. SoC devices are also referred to as system Large Scale Integration (LSI) or chipsets.
[0123]
　The memory 1906 is a volatile memory or a non-volatile memory or a combination thereof. Memory 1906 may include multiple physically independent memory devices. Volatile memory is, for example, SRAM or DRAM or a combination thereof. The non-volatile memory is MROM, EEPROM, flash memory, or hard disk drive, or any combination thereof. For example, the memory 1906 may include a baseband processor 1903, an application processor 1904, and an external memory device accessible by the SoC 1905. Memory 1906 may include embedded memory devices integrated within baseband processor 1903, application processor 1904, or SoC 1905. Further, the memory 1906 may include a memory within a Universal Integrated Circuit Card (UICC).
[0124]
　The memory 1906 may store one or more software modules (computer programs) 1907 including a command group and data for performing processing by the UE 12 described in the above-described embodiments. In some implementations, the baseband processor 1903 or the application processor 1904 is configured to read the software module 1907 from the memory 1906 and execute it to perform the processing of the UE 12 described in the above embodiments with reference to the drawings. May be done.
[0125]
　Note that the control plane processing and operation performed by the UE 12 described in the above embodiments are performed by other elements except the RF transceiver 1901 and the antenna array 1902, that is, at least one of the baseband processor 1903 and the application processor 1904, and the software module 1907. And a memory 1906 storing
[0126]
　As described with reference to FIGS. 17 and 18, each of the processors included in the RAN node 11 and the UE 12 according to the above-described embodiment includes an instruction group for causing a computer to execute the algorithm described with reference to the drawings. Execute one or more programs. This program can be stored using various types of non-transitory computer readable media, and can be supplied to a computer. Non-transitory computer readable media include various types of tangible storage media. Examples of non-transitory computer readable media are magnetic recording media (eg flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (eg magneto-optical disks), Compact Disc Read Only Memory (CD-ROM), CD- R, CD-R/W, semiconductor memory (for example, mask ROM, Programmable ROM (PROM), Erasable PROM (EPROM), flash ROM, Random Access Memory (RAM)) are included. In addition, the program may be supplied to the computer by various types of transitory computer readable media. Examples of transitory computer-readable media include electrical signals, optical signals, and electromagnetic waves. The temporary computer-readable medium can supply the program to the computer via a wired communication path such as an electric wire and an optical fiber, or a wireless communication path.
[0127]
The
　above-described embodiments may be implemented independently, or all or a part of the embodiments may be implemented in an appropriate combination.
[0128]
　In the above embodiment, switching of active BWP by DCI transmitted on NR PDCCH has been described. However, the switching of the active BWP in the above embodiment may be performed by the MAC CE or the timer (eg, BWP Inactivity Timer).
[0129]
　In the above-described embodiment, the explanation has been made mainly on the assumption that one BWP is activated for each UE (ie 1 active BWP per UE). However, it goes without saying that the method described in the above embodiments can be applied to the case where multiple BWPs are activated for each UE. For example, there may be multiple active BWPs in a BWP set. Further, there may be one active BWP corresponding to each of the plurality of BWP groups set in the BWP set, or there may be multiple active BWPs in the BWP group.
[0130]
　The 5G UE may be configured to measure beam quality in addition to cell quality and report these to RAN nodes (eg, gNB). In the above-described embodiment, the UE 12 may perform RLM and beam monitoring in combination. When the UE 12 detects a beam failure in a certain activated BWP and cannot perform beam recovery in the BWP (beam recovery failure), the UE 12 may operate as follows. That is, the layer 1 of the UE 12 is a beam in another BWP if the beam of another BWP (eg, another BWP in the BWP group) included in the same (physical) cell as the BWP is correctly detected. Notify layers 2 and 3 of the UE 12 of successful recovery (beam recovery successful). Although the layer 3 of the UE 12 has already detected the deterioration of the radio quality in the RLM, in the state before the RLF detection, the RLF timer and the counter are stopped based on the notification from the L1 and the normal RLM operation is started. You may come back.
[0131]
　The embodiments described above can also be applied to MR-DC (eg, EN-DC) and NR-NR DC. For example, active BWP in SCG may be switched by DCI transmitted in (NR) PDCCH. In this case, the RAN node (ie, SN) operating the SCG transmits the (NR) PDCCH in the DL active BWP of the SCG, and the UE 12 responds to the reception of the PDCCH (that is, DCI), and the above-described embodiment is performed. You may switch the DL active BWP according to either of the above. On the other hand, when the active BWP in SCG is switched with the change of cell defining SSB, the RAN node (ie, The MN) may send an active BWP switching instruction accompanied by a cell defining SSB change in the SCG in the MCG cell (or DL ​​active BWP). The UE 12 may switch the active BWP in the SCG according to any of the above-described embodiments in response to receiving the instruction. For example, in NR-NR DC, SgNB may transmit the control information including the active BWP switching instruction to the Master gNB (MgNB) in the SN MODIFICATION REQUEST ACKNOWLEDGE message in the SN Modification procedure. And MgNB may transmit the said control information to UE12 by a RRC Reconfiguration message. Alternatively, in (NG-)EN-DC, the SgNB may transmit the control information to the Master eNB (MeNB) with an SN MODIFICATION REQUEST ACKNOWLEDGE message in the SN Modification procedure. Then, the MeNB may transmit the control information to the UE 12 using an RRC Connection Reconfiguration message. Instead of this, the SgNB may directly transmit the control information to the UE 12 using a signaling bearer (eg, SRB3) in SCG.
[0132]
　In the above embodiment, the term cell defining SSB is used, but this refers to the BWP corresponding to the cell (physical cell) of the UE, or the SSB representing the BWP group corresponding to the set of the physical cells, May be called cell representative SSB. Alternatively, the cell defining SSB may be called a cell specifying SSB from the viewpoint of specifying a representative cell (physical cell) including the SSB. Further, the cell defining SSB may be referred to as a serving SSB because it is the SSB that the UE should monitor when staying in either the BWP or BWP group that contains it.
[0133]
　The sub PCI described in the above embodiment may be associated with the BWP index.
[0134]
　The reference BWP described in the above embodiments may be referred to as default BWP, initial BWP, reference BWP, primary BWP, anchor BWP, or master BWP. That is, the BWP staying first when the UE first accesses the RAN node (ie, when transitioning from Idle mode to Connected mode) is the reference BWP, default BWP, initial BWP, reference BWP, primary BWP, anchor BWP. , Or master BWP. Further or alternatively, among the plurality of BWPs included in the system band, the BWP that is not the reference BWP may be referred to as sub BWP, secondary BWP, and slave BWP.
[0135]
　Further, the above-described embodiment is merely an example regarding application of the technical idea obtained by the present inventor. That is, the technical idea is not limited to the above-described embodiment, and it goes without saying that various modifications can be made.
[0136]
　The whole or part of the exemplary embodiments disclosed above can be described as, but not limited to, the following supplementary notes.
[0137]
(Supplementary Note 1) A
　wireless terminal
　,
　comprising: a memory; and at least one processor coupled to the memory
,
　wherein the at least one processor is down without changing a cell-specific synchronization signal block (SSB). When the link bandwidth part (BWP) is switched from the first BWP to the second BWP, if the reference signal type for Radio Link Monitoring (RLM) is set to SSB type, then to the second BWP. A
wireless terminal configured to continue to use the first SSB associated with the first BWP for RLM measurements after switching the downlink BWP of .
[0138]
(Supplementary Note 2) The
　at least one processor is configured to perform the downlink depending on whether the reference signal type for the RLM is the SSB type or the Channel State Information Reference Signal (CSI-RS) type.
The wireless terminal of claim 1, configured to determine whether to change the reference signal used for the RLM measurement after switching BWP .
[0139]
(Supplementary note 3) The
　at least one processor, if the downlink BWP is switched from the first BWP to the second BWP without changing the cell specific SSB, the reference for the RLM If the signal type is set to Channel State Information Reference Signal (CSI-RS) type, then instead of the first CSI-RS in the first BWP, the second CSI-RS in the second BWP.
The wireless terminal according to claim 1 or 2, which is configured to be used for the RLM measurement .
[0140]
(Supplementary Note 4) The
　at least one processor is configured to take over the parameters related to the RLM when the downlink BWP is switched from the first BWP to the second BWP without changing the cell-specific SSB.
　4.
The wireless terminal according to any one of appendices 1 to 3 , wherein the parameter includes a count value of a timer that is started to determine the RLF in response to the out-of-sync continuation for a predetermined number of times .
[0141]
(Supplementary note 5) The
　at least one processor, if the downlink BWP is switched from the first BWP to the second BWP without changing the cell-specific SSB, 5. The
wireless terminal according to any one of appendices 1 to 4, configured to use the second CSI-RS in the second BWP instead of the one CSI-RS for CSI measurement .
[0142]
(Supplementary note 6) The
　at least one processor, if instructed to switch the downlink BWP from the first BWP to the second BWP with a change of the cell specific SSB, if for the RLM If the reference signal type is set to the SSB type, and the first of the first associated with the BWP of SSB to cease to use for the RLM measurement,
Appendix 1 5. The wireless terminal according to any one of 5 above.
[0143]
(Supplementary note 7) The
　at least one processor, if instructed to switch the downlink BWP from the first BWP to the second BWP with a change of the cell specific SSB, if for the RLM If the reference signal type is set to the SSB type, the second SSB associated with the second BWP is replaced with the second SSB associated with the second BWP instead of the first SSB associated with the first BWP.
The wireless terminal according to any one of appendices 1 to 6, which is configured to be used for .
[0144]
(Supplementary note 8) The
　at least one processor is dependent on whether the switching of the downlink BWP from the first BWP to the second BWP involves changing the cell-specific SSB. 8. The
wireless terminal of any one of appendices 1-7, configured to determine whether to continue to use the first SSB associated with the BWP for the RLM measurement .
[0145]
(Supplementary note 9) The
　at least one processor, if instructed to switch the downlink BWP from the first BWP to the second BWP with a change of the cell specific SSB, if for the RLM If the reference signal type is set to the SSB type, it is configured to reset a parameter for the RLM, the parameter
　being started to determine an RLF in response to a predetermined number of out-of-sync times. 9. The
wireless terminal according to any one of appendices 6 to 8, including a count value of a timer .
[0146]
(Supplementary Note 10) The
　RLM measurement measures downlink radio quality of a serving cell for the purpose of detecting out of synchronization and Radio Link Failure (RLF) when the radio terminal is in a connected mode.
8. The wireless terminal according to any one of appendices 1 to 7 , including:
[0147]
(Supplementary note 11) The
　CSI measurement transmits a report including a Channel Quality Indicator (CQI) used for at least one of scheduling and link adaptation to a radio access network node when the radio terminal is in a connected mode.
The wireless terminal according to appendix 5, comprising: measuring downlink radio quality of a serving cell for the purpose .
[0148]
(Supplementary note 12)
　A method in a wireless terminal, wherein
　when a downlink bandwidth part (BWP) is switched from a first BWP to a second BWP without changing a cell-specific synchronization signal block (SSB), Radio If the reference signal type for Link Monitoring (RLM) is set to SSB type, after switching the downlink BWP to the second BWP, the first SSB associated with the first BWP is switched to the first SSB. Continuing to use for RLM measurements
.
[0149]
(Appendix 13) The
　RLM measurement after switching the downlink BWP, depending on whether the reference signal type for the RLM is the SSB type or the Channel State Information Reference Signal (CSI-RS) type.
13. The method of claim 12, further comprising determining whether to change the reference signal used for the .
[0150]
(Supplementary Note 14) If the
　downlink BWP is switched from the first BWP to the second BWP without changing the cell specific SSB, the reference signal type for the RLM is Channel State Information Reference. If it is set to Signal (CSI-RS) type, instead of the first CSI-RS in the first BWP, the second CSI-RS in the second BWP is used for the RLM measurement.
The method of claim 12 or 13 , further comprising using.
[0151]
(Supplementary Note 15)
　When the downlink BWP is switched from the first BWP to the second BWP without changing the cell-specific SSB, further
　comprising taking over a parameter relating to the RLM, wherein the parameter: 15. The method according to
any one of appendices 12 to 14, including a count value of a timer that is started to determine the RLF in response to the out-of-synchronization having continued for a predetermined number of times .
[0152]
(Supplementary note 16)
　When the downlink BWP is switched from the first BWP to the second BWP without changing the cell specific SSB, the first CSI-RS in the first BWP is replaced. The method of any one of claims 12-15, further comprising: using a second CSI-RS in the second BWP for CSI measurements
.
[0153]
(Supplementary Note 17)
　If it is instructed to switch the downlink BWP from the first BWP to the second BWP with the change of the cell-specific SSB, if the reference signal type for the RLM is the SSB. if set to the type, the further comprising cease the first SSB associated with the first BWP used for the RLM measurement,
any one of appendices 12-16 The method described.
[0154]
(Supplementary Note 18)
　If it is instructed to switch the downlink BWP from the first BWP to the second BWP with the change of the cell specific SSB, if the reference signal type for the RLM is the SSB. If set to type, further comprising using a second SSB associated with the second BWP for the RLM measurement instead of the first SSB associated with the first BWP. comprising,
a method according to any one of appendices 12-17.
[0155]
(Supplementary note 19)
　Depending on whether switching of the downlink BWP from the first BWP to the second BWP involves a change of the cell-specific SSB, the one associated with the first BWP. 19.
The method of any one of appendices 12-18 , further comprising determining whether to continue to use a first SSB for the RLM measurement .
[0156]
(Supplementary Note 20)
　If it is instructed to switch the downlink BWP from the first BWP to the second BWP with the change of the cell-specific SSB, if the reference signal type for the RLM is the SSB. If set to type, further
　comprising resetting a parameter for said RLM, said parameter comprising a count value of a timer started to determine RLF in response to a predetermined number of out-of-sync times. ,
the method according to any one of appendices 17-19.
[0157]
(Supplementary note 21) The
　RLM measurement measures downlink radio quality of a serving cell for the purpose of detecting out of synchronization and detecting Radio Link Failure (RLF) when the radio terminal is in a connected mode.
21. The method according to any one of appendices 12 to 20 , which comprises:
[0158]
(Supplementary note 22) The
　CSI measurement transmits a report including a Channel Quality Indicator (CQI) used for at least one of scheduling and link adaptation to a radio access network node when the radio terminal is in a connected mode.
The method of claim 16 comprising measuring downlink radio quality of a serving cell for the purpose of:
[0159]
(Supplementary note 23)
　A program for causing a computer to perform the method in a wireless terminal, the method
　comprising a first BWP having a downlink bandwidth part (BWP) without changing a cell-specific synchronization signal block (SSB). From the second BWP to the second BWP, if the reference signal type for Radio Link Monitoring (RLM) is set to SSB type, after switching the downlink BWP to the second BWP, A
program comprising continuing to use a first SSB associated with one BWP for RLM measurements .
[0160]
　This application claims the priority on the basis of Japanese application Japanese Patent Application No. 2017-218040 for which it applied on November 13, 2017, and takes in those the indications of all here.
Explanation of symbols
[0161]
11 RAN node
12 UE
1804 processor
1805 memory
1903 baseband processor
1904 application processor
1906 memory

claims
[Claim 1]
　A wireless terminal,
　a memory,
　and at least one processor coupled to said memory,
comprising a
　at least one processor is cell-specific synchronization signal block (SSB) in the downlink without changing bandwidth part ( BWP) is switched from a first BWP to a second BWP, if the reference signal type for Radio Link Monitoring (RLM) is set to SSB type, the downlink to the second BWP. A
wireless terminal configured to continue to use the first SSB associated with the first BWP for RLM measurements after switching the BWP .
[Claim 2]
　The at least one processor, after switching the downlink BWP, depending on whether the reference signal type for the RLM is the SSB type or the Channel State Information Reference Signal (CSI-RS) type;
The wireless terminal according to claim 1, wherein the wireless terminal is configured to determine whether to change a reference signal used for the RLM measurement .
[Claim 3]
　The at least one processor is configured such that if the downlink BWP is switched from the first BWP to the second BWP without changing the cell specific SSB, the reference signal type for the RLM is Channel. If the State Information Reference Signal (CSI-RS) type is set, the second CSI-RS in the second BWP instead of the first CSI-RS in the first BWP is subjected to the RLM measurement. A
wireless terminal according to claim 1 or 2, configured for use for .
[Claim 4]
　Wherein the at least one processor is the case where the downlink BWP without changing the cell-specific SSB is switched from the first BWP to the second BWP, configured to take over the parameters relating to the RLM,
　the parameter
The wireless terminal according to any one of claims 1 to 3, wherein includes a count value of a timer that is started to determine the RLF in response to the out-of-synchronization being continued a predetermined number of times .
[Claim 5]
　The at least one processor may include a first CSI- in the first BWP if the downlink BWP is switched from the first BWP to the second BWP without changing the cell-specific SSB.
The wireless terminal according to any one of claims 1 to 4, which is configured to use a second CSI-RS in the second BWP instead of the RS for CSI measurement .
[Claim 6]
　The at least one processor is instructed to switch the downlink BWP from the first BWP to the second BWP with a modification of the cell specific SSB, if the reference signal type for the RLM is There the If set to SSB type, wherein associated with the first BWP said first SSB RLM configured to discontinue the use for measurement,
any of claims 1 to 5, The wireless terminal according to Item 1.
[Claim 7]
　The at least one processor is instructed to switch the downlink BWP from the first BWP to the second BWP with a modification of the cell specific SSB, if the reference signal type for the RLM is Is set to the SSB type, the second SSB associated with the second BWP is used for the RLM measurement instead of the first SSB associated with the first BWP.
The wireless terminal according to claim 1 , configured as described above.
[Claim 8]
　The at least one processor associates with the first BWP depending on whether switching the downlink BWP from the first BWP to the second BWP involves changing the cell-specific SSB.
The wireless terminal according to any one of claims 1 to 7, wherein the wireless terminal is configured to determine whether to continue to use the obtained first SSB for the RLM measurement .
[Claim 9]
　The at least one processor is instructed to switch the downlink BWP from the first BWP to the second BWP with a change of the cell specific SSB, if the reference signal type for the RLM is Is set to the SSB type, the
　parameter is configured to reset the parameters for the RLM, the parameter is a count value of a timer started to determine the RLF in response to a predetermined number of times out of synchronization.
The wireless terminal according to claim 6 , further comprising:
[Claim 10]
　The RLM measurement includes measuring downlink radio quality of a serving cell for the purpose of detecting out of synchronization and Radio Link Failure (RLF) when the wireless terminal is in a connected mode,
The wireless terminal according to any one of claims 1 to 7.
[Claim 11]
　The CSI measurement is intended to send a report including a Channel Quality Indicator (CQI) used for scheduling and/or link adaptation to a radio access network node when the radio terminal is in a connected mode.
The wireless terminal of claim 5, comprising measuring downlink radio quality of a serving cell .
[Claim 12]
　A method in a wireless terminal, wherein if the
　downlink bandwidth part (BWP) is switched from the first BWP to the second BWP without changing the cell specific synchronization signal block (SSB), if Radio Link Monitoring (RLM ) Is set to the SSB type, the first SSB associated with the first BWP for RLM measurement after switching the downlink BWP to the second BWP. And continuing to use
.
[Claim 13]
　Used for the RLM measurement after switching the downlink BWP depending on whether the reference signal type for the RLM is the SSB type or the Channel State Information Reference Signal (CSI-RS) type.
13. The method of claim 12, further comprising determining whether to modify the reference signal that is performed .
[Claim 14]
　If the downlink BWP is switched from the first BWP to the second BWP without changing the cell-specific SSB, the reference signal type for the RLM is Channel State Information Reference Signal (CSI- RS) type is set to use a second CSI-RS in the second BWP instead of the first CSI-RS in the first BWP for the RLM measurement.
The method according to claim 12 or 13 , further comprising :
[Claim 15]
　When the downlink BWP is switched from the first BWP to the second BWP without changing the cell-specific SSB, the method further
　comprises taking over a parameter for the RLM, the parameter being out of sync predetermined. The method according to
any one of claims 12 to 14, comprising a count value of a timer that is started to determine RLF in response to the number of consecutive times .
[Claim 16]
　When the downlink BWP is switched from the first BWP to the second BWP without changing the cell-specific SSB, the second CWP is replaced with the second CSI-RS in the first BWP.
16. The method according to any one of claims 12 to 15 , further comprising using a second CSI-RS in the BWP of the for CSI measurement .
[Claim 17]
　If instructed to switch the downlink BWP from the first BWP to the second BWP with a change of the cell specific SSB, the reference signal type for the RLM is set to the SSB type. If so,
the method of any one of claims 12-16, further comprising discontinuing using the first SSB associated with the first BWP for the RLM measurement. ..
[Claim 18]
　If instructed to switch the downlink BWP from the first BWP to the second BWP with a change of the cell specific SSB, the reference signal type for the RLM is set to the SSB type. If it has, further comprising using a second SSB associated with the second BWP instead of the said associated with the first BWP first SSB for the RLM measurement,
claim The method according to any one of 12 to 17.
[Claim 19]
　The first SSB associated with the first BWP depending on whether switching the downlink BWP from the first BWP to the second BWP involves changing the cell-specific SSB.
The method according to any one of claims 12-18 , further comprising determining whether to continue to use for the RLM measurement .
[Claim 20]
　If instructed to switch the downlink BWP from the first BWP to the second BWP with a change of the cell specific SSB, the reference signal type for the RLM is set to the SSB type. If it has, further comprising resetting the parameters relating to the RLM,
　the parameters include a count value of a timer is started to determine RLF according to the desynchronization has a predetermined number of times in succession,
according to claim 17 Item 20. The method according to any one of Items 1 to 19.
[Claim 21]
　The RLM measurement includes measuring downlink radio quality of a serving cell for the purpose of detecting out of synchronization and detecting Radio Link Failure (RLF) when the wireless terminal is in a connected mode,
The method according to any one of claims 12 to 20.
[Claim 22]
　The CSI measurement is intended to send a report including a Channel Quality Indicator (CQI) used for at least one of scheduling and link adaptation to a radio access network node when the radio terminal is in a connected mode. 17. The
method of claim 16, comprising measuring downlink radio quality of a serving cell .
[Claim 23]
　A non-transitory computer readable medium storing a program for causing a computer to perform a method in a wireless terminal, the method
　comprising a downlink bandwidth part (BWP) without modification of a cell specific synchronization signal block (SSB). ) Is switched from the first BWP to the second BWP, if the reference signal type for Radio Link Monitoring (RLM) is set to SSB type, the downlink BWP to the second BWP. A
non-transitory computer readable medium comprising continuing to use a first SSB associated with the first BWP for RLM measurements after switching .