WO2023013028A1 - Terminal and wireless communication method - Google Patents

Abstract

A terminal according to the present invention receives a beam from a transmission/reception point and, without executing an initial access procedure, activates a secondary cell group in an inactive state according to generation of uplink data or an instruction from a network. The terminal detects a beam failure before expiration of a transmission timing adjustment timer, and when the number of times of the failures reaches a specified number of times, executes the initial access procedure.

Description

Terminal and wireless communication method

The present disclosure relates to a terminal and wireless communication method compatible with dual connectivity.

The 3rd Generation Partnership Project (3GPP) has specified the 5th generation mobile communication system (also called 5G, New Radio (NR) or Next Generation (NG)), and the next generation specification called Beyond 5G, 5G Evolution or 6G We are also proceeding with

In Release-17 of 3GPP, expansion of Multi-RAT Dual Connectivity (MR-DC) is being considered. activation/deactivation mechanism (which may be referred to as SCG activation/deactivation) has been studied (Non-Patent Document 1).

Also, when activating (which may be referred to as reactivating) a deactivated SCG, the UE does not perform the initial access procedure (random access channel (RACH)), and the primary It is proposed to monitor the downlink control channel (PDCCH: Physical Downlink Control Channel) in the secondary cell (PSCell), and that the UE supports constant beam monitoring for deactivated SCG (Non-Patent Document 2). .

　The above deactivated SCG activation without RACH (RACH-less SCG activation) is not necessarily appropriate in cases such as beam failure detection.

Therefore, the following disclosure is made in view of this situation, and aims to provide a terminal and a wireless communication method that can realize more appropriate deactivated SCG activation.

One aspect of the present disclosure is a receiving unit (radio communication unit 210) that receives a beam from a transmission/reception point, and an inactive secondary cell group in response to the generation of uplink data or an instruction from the network for initial access. A control unit (control unit 240) that activates without executing a procedure, the control unit detects failure of the beam before the transmission timing adjustment timer expires, and the number of failures reaches a specified number of times. , the terminal (UE 200) executes the initial access procedure.

One aspect of the present disclosure is a receiving unit (radio communication unit 210) that receives a message instructing deactivation of a secondary cell group, and a secondary cell in an inactive state in response to generation of uplink data or an instruction from the network a control unit (control unit 240) for activating the group without performing an initial access procedure, wherein the receiving unit receives a transmission timing adjustment command transmitted together with the message; A terminal (UE 200) that starts a transmission timing adjustment timer based on a transmission timing adjustment command, executes the initial access procedure, and activates the inactive secondary cell group when a specific condition is satisfied.

One aspect of the present disclosure is a transmission unit (RRC processing unit 220) that transmits a message requesting activation of an inactive secondary cell group, and an inactive state in response to the generation of uplink data or an instruction from the network a control unit (control unit 240) that performs an initial access procedure or activates the secondary cell group without performing the initial access procedure, and the transmission unit performs the initial access procedure or It is a terminal (UE 200) that transmits the message including information indicating whether or not.

One aspect of the present disclosure is the step of receiving beams from a transmit/receive point and activating an inactive secondary cell group without performing an initial access procedure in response to generation of uplink data or an indication from the network. and detecting failures in the beam before a transmission timing adjustment timer expires, and executing the initial access procedure when the number of failures reaches a specified number of times. be.

One aspect of the present disclosure includes the step of receiving a message instructing deactivation of a secondary cell group, and, in response to generation of uplink data or an indication from the network, deactivating the inactive secondary cell group in an initial access procedure. receiving a send timing adjustment command sent with said message; starting a send timing adjustment timer based on said send timing adjustment command; performing the initial access procedure and activating the inactive secondary cell group if so.

One aspect of the present disclosure is a step of transmitting a message requesting activation of an inactive secondary cell group, and initializing the inactive secondary cell group in response to generation of uplink data or an instruction from the network. A wireless communication method comprising: performing an access procedure or activating without performing said initial access procedure; and transmitting said message containing information indicating whether to perform said initial access procedure. be.

FIG. 1 is an overall schematic configuration diagram of a radio communication system 10. As shown in FIG. FIG. 2 is a functional block configuration diagram of the eNB100A. FIG. 3 is a functional block configuration diagram of UE200. FIG. 4 is a diagram illustrating a timing example (Case 1) of various events related to RACH-less SCG activation according to Operation Example 1. FIG. FIG. 5 is a diagram showing a timing example (Case 2) of various events related to RACH-less SCG activation according to Operation Example 1. As shown in FIG. FIG. 6 is a diagram showing a timing example (Case 3) of various events related to RACH-less SCG activation according to Operation Example 1. FIG. FIG. 7 is a diagram illustrating a timing example (Case 4) of various events related to RACH-less SCG activation according to Operation Example 1. FIG. FIG. 8 is a diagram illustrating a sequence example of SCGdeactivation and SCGactivation according to Operation Example 2. FIG. FIG. 9 is a diagram showing an example of the hardware configuration of eNB100A, gNB100B and UE200.

Hereinafter, embodiments will be described based on the drawings. The same or similar reference numerals are given to the same functions and configurations, and the description thereof will be omitted as appropriate.

(1) Overall Schematic Configuration of Radio Communication System FIG. 1 is an overall schematic configuration diagram of a radio communication system 10 according to the present embodiment. The radio communication system 10 is a radio communication system according to Long Term Evolution (LTE) and 5G New Radio (NR). Note that LTE may be called 4G, and NR may be called 5G. Also, the radio communication system 10 may be a radio communication system conforming to a scheme called Beyond 5G, 5G Evolution, or 6G.

LTE and NR may be interpreted as radio access technology (RAT), and in this embodiment, LTE may be referred to as the first radio access technology and NR may be referred to as the second radio access technology.

The wireless communication system 10 includes an Evolved Universal Terrestrial Radio Access Network 20 (hereinafter E-UTRAN 20) and a Next Generation-Radio Access Network 30 (hereinafter NG RAN 30). The wireless communication system 10 also includes a terminal 200 (hereafter UE 200, User Equipment).

　E-UTRAN20 includes eNB100A, which is a radio base station conforming to LTE. NG RAN30 includes gNB100B, a radio base station according to 5G (NR). Also, the NG RAN 30 may be connected to a User Plane Function (not shown) that is included in the 5G system architecture and provides user plane functions. Note that E-UTRAN 20 and NG RAN 30 (which may be eNB100A or gNB100B) may simply be referred to as networks.

The eNB100A, gNB100B, and UE200 can support carrier aggregation (CA) using multiple component carriers (CC), and dual connectivity that simultaneously transmits component carriers between multiple NG-RAN Nodes and UEs. .

The eNB100A and gNB100B (radio base stations) may transmit and receive radio signals via one or more transmission and reception points (TRP: Transmission and Reception Points). eNB100A and gNB100B can support single-user MIMO using one TRP, and coordinate two TRPs to support distributed MIMO transmission of a predetermined channel (eg, PDSCH: Physical Downlink Shared Channel).

　TRP may be read interchangeably as cell, radio base station, Node B, antenna port, antenna port group, antenna panel, panel, antenna element, transmission/reception point, etc.

eNB100A, gNB100B and UE200 perform radio communication via radio bearers, specifically Signaling Radio Bearer (SRB) or DRB Data Radio Bearer (DRB).

In this embodiment, eNB100A configures the master node (MN) and gNB100B configures the secondary node (SN) Multi-Radio Dual Connectivity (MR-DC), specifically E-UTRA-NR Dual Connectivity ( EN-DC) or NR-E-UTRA Dual Connectivity (NE-DC) in which the gNB 100B configures the MN and the eNB 100A configures the SN. Alternatively, NR-NR Dual Connectivity (NR-DC) may be implemented in which the gNB configures the MN and SN.

In this way, UE200 supports dual connectivity connecting to eNB100A and gNB100B.

eNB100A is included in the master cell group (MCG) and gNB100B is included in the secondary cell group (SCG). In other words, gNB100B is an SN included in the SCG.

The eNB100A and gNB100B may be called radio base stations or network devices.

In addition, the wireless communication system 10 may support addition or change (PSCell addition/change) of Primary SCell (PSCell). Note that the PSCell addition/change may include conditional PSCell addition/change.

A PSCell is a type of secondary cell. PSCell means Primary SCell (secondary cell), and may be interpreted as corresponding to any SCell among a plurality of SCells.

A secondary cell may be read as a secondary node (SN) or a secondary cell group (SCG).

(2) Functional Block Configuration of Radio Communication System Next, the functional block configuration of the radio communication system 10 will be described. Specifically, functional block configurations of eNB 100A and UE 200 will be described.

(2.1) eNB100A
FIG. 2 is a functional block configuration diagram of the eNB100A. As shown in FIG. 2, the eNB 100A includes a radio communication section 110, an RRC processing section 120, a DC processing section 130 and a control section 140. The gNB100B may also have the same functions as the eNB100A, although the gNB100B is different in that it supports NR.

The radio communication unit 110 transmits downlink signals (DL signals) according to LTE. Radio communication section 110 also receives an uplink signal (UL signal) according to LTE.

In addition, the radio communication unit 110 performs PDU/SDU assembly/ Perform disassembly, etc.

The RRC processing unit 120 executes various processes in the radio resource control layer (RRC). Specifically, RRC processing section 120 can transmit RRC Reconfiguration to UE 200 . Also, RRC processing section 120 can receive RRC Reconfiguration Complete, which is a response to RRC Reconfiguration, from UE 200 .

In addition, in this embodiment, the eNB 100A supports LTE, but in this case, the name of the RRC message may be RRC Connection Reconfiguration or RRC Connection Reconfiguration Complete.

In addition, RRC Reconfiguration (and RRC messages between MN and SN (inter-node RRC messages) may include reconfigurationWithSync regarding cell reconfiguration. reconfigurationWithSync is described in 3GPP TS38.331 5.3.5.5.2, etc. stipulated.

ReconfigurationWithSync may be interpreted as a common mechanism for activating cells (NR cells) (that is, adding NR cells) in non-standalone (NSA) including other RATs (such as LTE). UE200 can execute a random access procedure (RA procedure) and the like based on reconfigurationWithSync.

The DC processing unit 130 executes processing related to dual connectivity, specifically Multi-RAT Dual Connectivity (MR-DC). In this embodiment, the eNB 100A supports LTE and the gNB 100B supports NR, so DC processing section 130 may perform processing related to E-UTRA-NR Dual Connectivity (EN-DC). Note that the type of DC is not limited as described above, and may correspond to, for example, NR-E-UTRA Dual Connectivity (NE-DC) or NR-NR Dual Connectivity (NR-DC).

The DC processing unit 130 can transmit and receive messages defined in 3GPP TS37.340, etc., and execute processing related to DC setup and release between the eNB100A, gNB100B, and UE200.

The control unit 140 controls each functional block that configures the eNB 100A. In particular, in this embodiment, the control unit 140 performs control regarding addition or change of secondary cells (or secondary nodes).

Specifically, the control unit 140 can perform control related to activation/de-activation of the secondary cell group (SCG). Specifically, the control unit 140 activates (may be called activation) or deactivates (may be called inactivation) the SCG based on an instruction from the UE 200. You can More specifically, the control unit 140 may activate or deactivate one or more SCells (which may include PSCells; hereinafter the same) included in the SCG.

An active SCG (SCell) may be interpreted as a state in which the UE 200 can immediately use the SCG (SCell). An inactive SCG (SCell) may be interpreted as a state in which the UE 200 cannot immediately use the SCG (SCell), but configuration information is retained.

Note that in the present embodiment, channels include control channels and data channels. Control channels include PDCCH (Physical Downlink Control Channel), PUCCH (Physical Uplink Control Channel), PRACH (Physical Random Access Channel), and PBCH (Physical Broadcast Channel).

In addition, data channels include PDSCH (Physical Downlink Shared Channel) and PUSCH (Physical Uplink Shared Channel).

Reference signals include demodulation reference signal (DMRS), sounding reference signal (SRS), tracking reference signal (TRS), and channel state information-reference signal (CSI-RS). and a reference signal. Data may also refer to data transmitted over a data channel.

(2.2) UE200
FIG. 3 is a functional block configuration diagram of UE200. As shown in FIG. 3 , UE 200 includes radio communication section 210 , RRC processing section 220 , DC processing section 230 and control section 240 .

The radio communication unit 210 transmits an uplink signal (UL signal) according to LTE or NR. Also, radio communication section 210 receives a downlink signal (DL signal) according to LTE or NR. UL and DL signals may consist of one or more beams.

Specifically, the radio communication unit 210 can receive beams from one or more transmission/reception points (TRPs) and transmit beams toward radio base stations (TRPs). In this embodiment, the wireless communication unit 210 may constitute a receiving unit that receives beams from transmission/reception points.

In other words, UE200 can access eNB100A (E-UTRAN20) and gNB100B (NG RAN30), and can support dual connectivity (specifically, EN-DC). In this way, UE 200 can transmit and receive radio signals via MCG or SCG, specifically via cells included in MCG or cells included in SCG (SCell including PSCell).

Also, the radio communication unit 210 performs assembly/disassembly of PDU/SDU in MAC, RLC, PDCP, etc., like the radio communication unit 110 of the eNB100A (gNB100B).

The RRC processing unit 220 executes various processes in the radio resource control layer (RRC). Specifically, the RRC processing unit 220 can transmit and receive radio resource control layer messages.

The RRC processing unit 220 can receive RRC Reconfiguration from the network, specifically from the E-UTRAN 20 (or NG RAN 30). Also, the RRC processing unit 220 can transmit RRC Reconfiguration Complete, which is a response to RRC Reconfiguration, to the network.

The RRC processing unit 220 may transmit or receive other messages in the RRC layer. In particular, in this embodiment, the RRC processing unit 220 may receive a message instructing SCG deactivation (SCG deactivation) or a message for activation (SCG activation) from the network. In this embodiment, the RRC processing unit 220 may configure a receiving unit that receives a message instructing deactivation of SCG. Note that this message may be included in RRC Reconfiguration or the like.

Furthermore, the RRC processing unit 220 may transmit a message requesting activation of a deactivated SCG to the network. In this embodiment, the RRC processing unit 220 may configure a transmitting unit that transmits a message requesting activation of deactivated SCG.

The RRC processing unit 220 may transmit the message including information indicating whether to execute the initial access procedure. An initial access procedure is a procedure that is performed for UE 200 to access (or connect to) a network (specifically, eNB 100A or gNB 100B). In particular, in the present embodiment, the initial access procedure may be interpreted as a procedure performed for the idle state UE 200 to connect to a cell included in the SCG, and may be a random access (RA) procedure.

RA procedures may include contention-free random access procedures (CFRA) and contention-based random access procedures (CBRA).

Also, the RRC processing unit 220 may receive a transmission timing adjustment command (Timing Advance (TA) command) transmitted together with the message (SCGdeactivation). TA command is a command used to adjust UL transmission timing, and may be indicated by an offset value from the reference timing. By adjusting the UL transmission timings of multiple UEs 200 using the TA command, the network can keep the UL signal reception timings within a predetermined cyclic prefix (CP).

The DC processing unit 230 executes processing related to dual connectivity, specifically MR-DC. As described above, in this embodiment, the DC processing unit 230 may perform processing related to EN-DC, but may also support NE-DC and/or NR-DC.

DC processing unit 230 accesses each of eNB100A and gNB100B, and multiple layers including RRC (medium access control layer (MAC), radio link control layer (RLC), and packet data convergence protocol layer ( PDCP), etc.) can be performed.

The DC processing unit 230 can send a report regarding SCG deactivation. A report on deactivation may be interpreted in a broad sense, and may include settings related to SCG activation or deactivation, explicit or implicit display of active or de-active state, transition to that state, and the like. .

The DC processing unit 230 can also transmit SCG failure information to the network. Specifically, the DC processing unit 230 may transmit an SCGFailureInformation message (or a new RRC message) via the RRC processing unit 220. SCGFailureInformation is specified in 3GPP TS38.331.

Specifically, when a failure occurs in a deactivated SCG (deactivated SCG), the DC processing unit 230 may transmit failure information (SCGFailureInformation) including an information element indicating the cell state of the SCG.

A deactivated SCG cell may be interpreted as a cell included in the deactivated SCG, and typically may be interpreted as an SCell including a PSCell. An information element (IE) is an element that constitutes SCGFailureInformation, and may include letters, numbers, symbols, etc., and may be called fields.

The DC processing unit 230 may transmit SCGFailureInformation including reception quality in the serving cell and neighbor cells.

The reception quality may include RSRP (Reference Signal Received Power), RSRQ (Reference Signal Received Quality) and SINR (Signal-to-Interference plus Noise power Ratio). RSRP is the reception level of the reference signal measured by the UE 200, and RSRQ is the reception quality of the reference signal measured by the UE 200 (the ratio of the power of the cell-specific reference signal to the total power within the reception bandwidth). may be interpreted).

In addition, the DC processing unit 230 can perform processing related to beam failure detection (BFD) and recovery (BFR) based on reception quality measurement results for beams transmitted from the network.

Note that the serving cell may simply be interpreted as the cell to which the UE 200 is connected, but more precisely, in the case of an RRC_CONNECTED UE in which carrier aggregation (CA) is not set, the number of serving cells that constitute the primary cell is 1. Only one. For RRC_CONNECTED UEs configured with CA, the serving cell may be taken to refer to the set of one or more cells including the primary cell and all secondary cells.

It should be noted that the above-mentioned deactivated SCG information element may be included in the SCGFailureInformation in part or in its entirety.

The control unit 240 controls each functional block that configures the UE200. In particular, in this embodiment, the control unit 240 can perform control regarding activation/de-activation of secondary cell groups (SCGs).

Specifically, the control unit 240 can activate (reactivate) an inactive SCG (deactivated SCG) without executing an initial access procedure (RA procedure). Such procedures may be referred to as RACH-less SCG activation (or RACH-less SCG re-activation). RACH-less SCG activation may be performed on the assumption that the synchronous state between UE 200 and SCG (SN) can be maintained.

The control unit 240 may execute RACH-less SCG activation when uplink (UL) data is generated inside the UE 200. Alternatively, the control unit 240 may perform RACH-less SCG activation in response to explicit or implicit instructions from the network. That is, the control unit 240 may activate the deactivated SCG without executing RACH in response to generation of UL data or an instruction from the network.

In addition, the control unit 240 detects a beam failure (BFD) before the transmission timing adjustment timer expires, and when the number of failures reaches a specified number of times, the initial access procedure (RA procedure) is executed. good.

The transmission timing adjustment timer is a timer used to adjust the UL transmission timing, and specifically, it may be interpreted as a Time Alignment timer (TA timer). Also, the transmission timing adjustment may be interpreted as delaying or advancing the transmission timing of the UL signal based on a predetermined reference timing, and the TA timer is the time during which the same transmission timing may be applied to the UL transmission. may be interpreted as a timer that measures Also, the TA timer is a timer for measuring the valid time of the TA value received by the TA command, and may start when the TA command is received.

The control unit 240 starts the transmission timing adjustment timer based on the transmission timing adjustment command (TA command) received from the network, executes the initial access procedure (RA procedure) when a specific condition is satisfied, and activates the deactivated SCG. It may be activated (reactivated).

For example, when the TA timer expires or BFD is detected, the control unit 240 may transmit RACH and activate deactivated SCG.

It should be noted that the inactive state of the SCG may be at least one of the following states.

　　· PUSCH has not been sent in the deactivated SCG.

　　・PDCCH is not monitored in PSCell of deactivated SCG.

· SCell dormancy (dormant state) is not supported for SCells in deactivated SCG.

· UE200 maintains the DL synchronization state.

· The UE 200 performs restricted RRM measurement.

　　・PSCell mobility is supported.

· The UE 200 performs limited radio link monitoring (RLM) and/or does not perform beam management (beam failure detection and restoration), SRS (Sounding Reference Signal) transmission, CSI reporting.

(3) Operation of Radio Communication System Next, the operation of the radio communication system 10 will be described. Specifically, operations related to activation/de-activation of a secondary cell group (SCG) will be described. More specifically, an operation example regarding activation (reactivation) of a deactivated SCG (deactivated SCG) will be described.

(3.1) Operation example 1
In deactivated SCG, the UE 200 has a reception beam monitoring function (RLM, BFD), and there is no BFD before the Time Alignment timer (TA timer, TAT) expires (or the number of BFDs reaches the maximum value (beamFailureInstanceMaxCount). If not reached), the RACH-less SCG activation may be performed inside the UE 200 when there is UL data arrival or an SCG activation instruction from the network.

In this operation example, furthermore, the operation when the UE 200 has BFD in an inactive PSCell before the TA timer expires and the number of BFDs exceeds the maximum number (beamFailureInstanceMaxCount) will be explained.

Specifically, the UE 200 may operate according to at least one of the following.

(i) CandidateBeamRSList is set in advance by beamFailureRecoveryConfig from the network to UE 200, UE 200 counts BFD in PSCells in an inactive state, and BFR may be executed when the value of BFI_COUNTER≧beamFailureInstanceMaxCount.
That is, UE 200 may transmit RACH on PSCell using RACH resources specified by candidateBeamRSList (list of candidate beams).

(ii) At this time, if there is no UL data arrival for the SCG bearer (radio bearer) or there is no SCG activation instruction from the network, the UE 200 transmits RACH on the PSCell and establishes UL/DL synchronization, The state of deactivated SCG (for example, PDCCH is not monitored) may be retained.

After that, if UL data arrival for SCG bearer occurs, if UL data amount for MCG split bearer exceeds ULDataSplitThreshold and SCG is required, or if there is the next SCG activation indication from the network, SCG activation may be performed.

(iii) Alternatively, UE 200 may transmit RACH on PSCell even though UL data arrival for SCG bearer has not occurred or there is no SCG activation instruction from the network. UE 200 may deactivate SCG again if UL data arrival does not occur within a predetermined period of time (or while a predetermined timer is running) after activating SCG (for example, starting monitoring of PDCCH).

(iv) Alternatively, if the value of BFI_COUNTER≧beamFailureInstanceMaxCount, UE 200 does not transmit RACH on PSCell (or does not transmit RACH because there is no candidateBeamRSList or no good beam), beam failure (radio Link failure (RLF) information (eg, beam identity and quality) may be reported to the network. The beam failure (RLF information) may be reported to the network by SCGFailureInformationmessage.

Also, the UE 200 may request SCG activation (which may include a dedicated RACH resource) from the network when UL data arrival occurs. Alternatively, UE 200 may wait for an SCG activation indication from the network. The SCG activation indication from the network may include candidateBeam information and dedicated RACH resource.

4, 5, 6, and 7 respectively show timing examples (cases 1 to 4) of various events related to RACH-less SCG activation according to operation example 1 described above. Here, we assume the application of RACH-less SCG activation.

FIG. 4 (Case 1) shows an example in which RACH-less SCG activation is applied because the number of BFDs has reached the maximum value (3) in deactivated SCG, but RACH is transmitted to PSCell, but PDCCH is not monitored. .

Fig. 5 (Case 2) shows an example of transmitting RACH to PSCell and monitoring PDCCH, although RACH-less SCG activation is applied because the number of BFDs has reached the maximum value (3) in deactivated SCG. In this case, the SCG may be deactivated again if no UL data arrival occurs.

FIG. 6 (Case 3) shows an example where the value of BFI_COUNTER≧beamFailureInstanceMaxCount, but the UE 200 does not execute BFR.

FIG. 7 (Case 4) shows an example in which the UE 200 does not have reception beam monitoring functions (RLM, BFD).

(v) UE 200 may continue RLM after executing BFR. Specifically, RLM may be continued while TAT is in operation, RLM may be continued even if TAT has expired, or RLM may be stopped when TAT has expired. Alternatively, the UE 200 may continue RLM after executing BFR if Tracking Reference Signal (TRS) is set.

(vi) Before the expiration of TAT (or after BFR), if BFD/RLF is not detected and UL data arrival occurs, or if there is an SCG activation instruction from the network, UE 200 performs SCG activation without sending RACH. may

Also, UE200 does not send RRC Reconfiguration from the network to UE200 during SCGdeactivation state when TCI (Transmission Configuration Indication) state and SRI (SRS resource indicator)/SRS resource config are set in advance. may

Note that the TCI state may mean that the setting is explicitly instructed by the control element (MAC CE) of the radio resource control layer (RRC) or medium access control layer (MAC). QCL relationships may include both cases where the TCI state is explicitly set and cases where the TCI state is not set. QCL/TCI state/beam may be read interchangeably.

If the SRI/SRS resource config is not set during the SCGdeactivation state, the SRI/SRS resource config may be set by RRC Reconfiguration when the network instructs SCG activation.

(3.2) Operation example 2
In this operation example, the TA command may be transmitted from the network to the UE 200 in the deactivated SCG.

Also, as described above, when RACH-less SCG activation is set, UE 200 needs to perform RACH-based SCG activation after TAT expires. Alternatively, the UE 200 needs to perform RACH based SCG activation if the beam quality is bad even before the TAT expires.

In this operation example, whether the UE 200 executes RACH-less SCG activation or RACH-based SCG activation is surely shared between the UE 200 and the network.

FIG. 8 shows a sequence example of SCGdeactivation and SCGactivation according to Operation Example 2.

(3.2.1) Trigger by Network As shown in FIG. 8 , the network may include the TA command in the SCGdeactivation instruction and transmit it to the UE 200 .

Alternatively, the network may transmit the TA command in conjunction with the transmission timing of the SCG deactivation instruction to the UE 200. The TA command may be sent at the same time as the SCG deactivation instruction, immediately before, or immediately after.

In the case of MN initiated SCGdeactivation initiated by MN, MN may request SN to send TA command, and SN may send TA command to UE200. Alternatively, the SN may transmit the TA command on the SCG side to the MN, and the MN may transmit the TA command to the UE200.

In the case of SN initiated SCGdeactivation by SN, TA command may be sent from SN to UE200 immediately before SCG deactivation. Alternatively, the SN may send the TA command to the MN, and the MN may send the TA command to the UE200.

(3.2.2) Trigger by UE 200 As shown in FIG. 8, UE 200 notifies preference of RACH-less SCG activation or RACH based SCG activation in accordance with transmission of SCG activation request to MN. good. The preference may be included in the SCG activation request.

In addition, the UE 200 has not expired the TAT but the beam quality is poor (beam quality information may be reported), so the reason for requesting RACH-based SCG activation (or RACH-based SCG activation for TAT expiration) It may be sent to the network.

When the network receives a preference for RACH-less SCG activation or RACH-based SCG activation, it may include RACH resource and candidate beam in the SCG activation indication (RRC Reconfiguration).

Also, if the TAT has not expired and UE 200 can perform RACH-less SCG activation, but the SCG activation indication from the network includes dedicated RACH resource and candidate beam information, UE 200 gives priority to RACH based activation. You may

(4) Functions and Effects According to the above-described embodiment, the following functions and effects are obtained. Specifically, for RACH-less SCG activation in deactivated SCG, UE 200 detects a beam failure (BFD) before TA timer expires, and if the number of failures reaches a specified number (beamFailureInstanceMaxCount), RA procedure (ie RACH based activation) may be performed.

For this reason, even if RACH-less SCG activation is applied to deactivated SCGs, if RACH is assumed to be necessary, reactivation of deactivated SCGs accompanied by RACH can be reliably achieved. That is, the UE 200 can achieve more appropriate deactivated SCG activation.

The UE 200 may perform the RA procedure (that is, RACH based activation) and reactivate the deactivated SCG if certain conditions are met. Also, the UE 200 can transmit a message (SCG activation request) including information indicating whether to execute the RA procedure (that is, RACH based activation) to the network.

Therefore, the network can more reliably provide the TA command to the UE200, and the UE200 and the network can reliably share whether the UE200 will perform RACH-less SCG activation or RACH-based SCG activation. That is, the UE 200 and the network can realize more appropriate deactivated SCG activation.

(5) Other Embodiments Although the embodiments have been described above, it is obvious to those skilled in the art that the present invention is not limited to the description of the embodiments, and that various modifications and improvements are possible.

For example, in the above-described embodiment, the initial access procedure is intended to be the RA procedure, but it is not limited to the RA procedure and can be interchanged with RACH transmission (or simply RACH) as described above. may be interpreted as a procedure performed for the UE 200 to access (attach or connect to) the network.

Also, in the above description, configure, activate, update, indicate, enable, specify, and select may be read interchangeably. good. Similarly, link, associate, correspond, and map may be read interchangeably to allocate, assign, monitor. , map, may also be read interchangeably.

Furthermore, specific, dedicated, UE-specific, and UE-specific may be read interchangeably. Similarly, common, shared, group-common, UE common, and UE shared may be read interchangeably.

Also, the block configuration diagrams (FIGS. 2 and 3) used to describe the above-described embodiment show blocks in units of functions. These functional blocks (components) are realized by any combination of at least one of hardware and software. Also, the method of implementing each functional block is not particularly limited. That is, each functional block may be implemented using one device physically or logically coupled, or directly or indirectly using two or more physically or logically separate devices (e.g. , wired, wireless, etc.) and may be implemented using these multiple devices. A functional block may be implemented by combining software in the one device or the plurality of devices.

Functions include judging, determining, determining, calculating, calculating, processing, deriving, investigating, searching, checking, receiving, transmitting, outputting, accessing, resolving, selecting, choosing, establishing, comparing, assuming, expecting, assuming, Broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, assigning, etc. can't For example, a functional block (component) that performs transmission is called a transmitting unit or transmitter. In either case, as described above, the implementation method is not particularly limited.

Furthermore, the above-described eNB100A, gNB100B and UE200 (applicable device) may function as a computer that performs processing of the wireless communication method of the present disclosure. FIG. 9 is a diagram showing an example of the hardware configuration of the device. As shown in FIG. 9, the device may be configured as a computing device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, and the like.

In the following explanation, the term "apparatus" can be read as a circuit, device, unit, or the like. The hardware configuration of the device may be configured to include one or more of each device shown in the figure, or may be configured without some of the devices.

Each functional block of the device (see Fig. 2.3) is realized by any hardware element of the computer device or a combination of the hardware elements.

In addition, each function of the device is implemented by causing the processor 1001 to perform calculations, controlling communication by the communication device 1004, and controlling the It is realized by controlling at least one of data reading and writing in 1002 and storage 1003 .

A processor 1001, for example, operates an operating system and controls the entire computer. The processor 1001 may be configured by a central processing unit (CPU) including interfaces with peripheral devices, a control unit, an arithmetic unit, registers, and the like.

Also, the processor 1001 reads programs (program codes), software modules, data, etc. from at least one of the storage 1003 and the communication device 1004 to the memory 1002, and executes various processes according to them. As the program, a program that causes a computer to execute at least part of the operations described in the above embodiments is used. Further, the various processes described above may be executed by one processor 1001, or may be executed by two or more processors 1001 simultaneously or sequentially. Processor 1001 may be implemented by one or more chips. Note that the program may be transmitted from a network via an electric communication line.

The memory 1002 is a computer-readable recording medium, and is composed of at least one of Read Only Memory (ROM), Erasable Programmable ROM (EPROM), Electrically Erasable Programmable ROM (EEPROM), Random Access Memory (RAM), etc. may be The memory 1002 may also be called a register, cache, main memory (main storage device), or the like. The memory 1002 can store programs (program code), software modules, etc. capable of executing a method according to an embodiment of the present disclosure.

The storage 1003 is a computer-readable recording medium, for example, an optical disc such as a Compact Disc ROM (CD-ROM), a hard disk drive, a flexible disc, a magneto-optical disc (for example, a compact disc, a digital versatile disc, a Blu-ray disk), smart card, flash memory (eg, card, stick, key drive), floppy disk, magnetic strip, and/or the like. Storage 1003 may also be referred to as an auxiliary storage device. The recording medium described above may be, for example, a database, server, or other suitable medium including at least one of memory 1002 and storage 1003 .

The communication device 1004 is hardware (transmitting/receiving device) for communicating between computers via at least one of a wired network and a wireless network, and is also called a network device, a network controller, a network card, a communication module, or the like.

The communication device 1004 includes a high-frequency switch, duplexer, filter, frequency synthesizer, etc., for realizing at least one of frequency division duplex (FDD) and time division duplex (TDD). may consist of

The input device 1005 is an input device (for example, keyboard, mouse, microphone, switch, button, sensor, etc.) that receives input from the outside. The output device 1006 is an output device (eg, display, speaker, LED lamp, etc.) that outputs to the outside. Note that the input device 1005 and the output device 1006 may be integrated (for example, a touch panel).

Also, each device such as the processor 1001 and the memory 1002 is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses between devices.

In addition, the device includes hardware such as a microprocessor, digital signal processor (DSP), application specific integrated circuit (ASIC), programmable logic device (PLD), field programmable gate array (FPGA), etc. A part or all of each functional block may be implemented by the hardware. For example, processor 1001 may be implemented using at least one of these pieces of hardware.

In addition, notification of information is not limited to the aspects/embodiments described in the present disclosure, and may be performed using other methods. For example, the notification of information may include physical layer signaling (e.g., Downlink Control Information (DCI), Uplink Control Information (UCI), higher layer signaling (e.g., RRC signaling, Medium Access Control (MAC) signaling, broadcast information (Master Information Block (MIB), System Information Block (SIB), other signals, or combinations thereof, and RRC signaling may also be referred to as RRC messages, e.g., RRC Connection Setup ) message, RRC Connection Reconfiguration message, or the like.

Each aspect/embodiment described in this disclosure includes Long Term Evolution (LTE), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, 4th generation mobile communication system (4G), 5th generation mobile communication system ( 5G), Future Radio Access (FRA), New Radio (NR), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi (registered trademark)) , IEEE 802.16 (WiMAX®), IEEE 802.20, Ultra-WideBand (UWB), Bluetooth®, other suitable systems, and/or next-generation systems enhanced therefrom. may be applied to Also, a plurality of systems may be applied in combination (for example, a combination of at least one of LTE and LTE-A and 5G).

The order of the processing procedures, sequences, flowcharts, etc. of each aspect/embodiment described in the present disclosure may be changed as long as there is no contradiction. For example, the methods described in this disclosure present elements of the various steps using a sample order, and are not limited to the specific order presented.

A specific operation that is performed by a base station in the present disclosure may be performed by its upper node in some cases. In a network consisting of one or more network nodes with a base station, various operations performed for communication with a terminal may be performed by the base station and other network nodes other than the base station (e.g. MME or S-GW, etc., but not limited to). Although the case where there is one network node other than the base station is exemplified above, it may be a combination of a plurality of other network nodes (for example, MME and S-GW).

Information, signals (information, etc.) can be output from a higher layer (or a lower layer) to a lower layer (or a higher layer). It may be input and output via multiple network nodes.

Input/output information may be stored in a specific location (for example, memory) or managed using a management table. Input and output information may be overwritten, updated, or appended. The output information may be deleted. The entered information may be transmitted to other devices.

The determination may be made by a value represented by one bit (0 or 1), by a true/false value (Boolean: true or false), or by numerical comparison (for example, a predetermined value).

Each aspect/embodiment described in the present disclosure may be used alone, may be used in combination, or may be used by switching along with execution. In addition, the notification of predetermined information (for example, notification of “being X”) is not limited to being performed explicitly, but may be performed implicitly (for example, not notifying the predetermined information). good too.

Software, whether referred to as software, firmware, middleware, microcode, hardware description language or otherwise, includes instructions, instruction sets, code, code segments, program code, programs, subprograms, and software modules. , applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, and the like.

In addition, software, instructions, information, etc. may be transmitted and received via a transmission medium. For example, the Software uses wired technology (coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL), etc.) and/or wireless technology (infrared, microwave, etc.) to access websites, Wired and/or wireless technologies are included within the definition of transmission medium when sent from a server or other remote source.

The information, signals, etc. described in this disclosure may be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may refer to voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, light fields or photons, or any of these. may be represented by a combination of

The terms explained in this disclosure and terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, the channel and/or symbols may be signaling. A signal may also be a message. A component carrier (CC) may also be called a carrier frequency, a cell, a frequency carrier, or the like.

The terms "system" and "network" used in this disclosure are used interchangeably.

In addition, the information, parameters, etc. described in the present disclosure may be expressed using absolute values, may be expressed using relative values from a predetermined value, or may be expressed using other corresponding information. may be represented. For example, radio resources may be indexed.

The names used for the parameters described above are not restrictive names in any respect. Further, the formulas, etc., using these parameters may differ from those expressly disclosed in this disclosure. Since the various channels (e.g., PUCCH, PDCCH, etc.) and information elements can be identified by any suitable designation, the various designations assigned to these various channels and information elements are in no way restrictive designations. isn't it.

In the present disclosure, "base station (BS)", "radio base station", "fixed station", "NodeB", "eNodeB (eNB)", "gNodeB (gNB)", " "access point", "transmission point", "reception point", "transmission/reception point", "cell", "sector", "cell group", " Terms such as "carrier", "component carrier" may be used interchangeably. A base station may also be referred to by terms such as macrocell, small cell, femtocell, picocell, and the like.

A base station can accommodate one or more (eg, three) cells (also called sectors). When a base station accommodates multiple cells, the overall coverage area of the base station can be partitioned into multiple smaller areas, each smaller area corresponding to a base station subsystem (e.g., a small indoor base station (Remote Radio)). Head: RRH) can also provide communication services.

The term "cell" or "sector" refers to part or all of the coverage area of at least one of a base station and base station subsystem that provides communication services in this coverage.

In this disclosure, terms such as "Mobile Station (MS)", "user terminal", "User Equipment (UE)", "terminal" may be used interchangeably. .

A mobile station is defined by those skilled in the art as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless It may also be called a terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable term.

At least one of the base station and mobile station may be called a transmitting device, a receiving device, a communication device, or the like. At least one of the base station and the mobile station may be a device mounted on a mobile object, the mobile object itself, or the like. The mobile body may be a vehicle (e.g., car, airplane, etc.), an unmanned mobile body (e.g., drone, self-driving car, etc.), or a robot (manned or unmanned ). Note that at least one of the base station and the mobile station includes devices that do not necessarily move during communication operations. For example, at least one of the base station and mobile station may be an Internet of Things (IoT) device such as a sensor.

Also, the base station in the present disclosure may be read as a mobile station (user terminal, hereinafter the same). For example, communication between a base station and a mobile station is replaced with communication between multiple mobile stations (for example, Device-to-Device (D2D), Vehicle-to-Everything (V2X), etc.) Regarding the configuration, each aspect/embodiment of the present disclosure may be applied. In this case, the mobile station may have the functions that the base station has. Also, words such as "up" and "down" may be replaced with words corresponding to inter-terminal communication (for example, "side"). For example, uplink channels, downlink channels, etc. may be read as side channels.

Similarly, mobile stations in the present disclosure may be read as base stations. In this case, the base station may have the functions that the mobile station has.
A radio frame may consist of one or more frames in the time domain. Each frame or frames in the time domain may be referred to as a subframe. A subframe may also consist of one or more slots in the time domain. A subframe may be a fixed time length (eg, 1 ms) independent of numerology.

A numerology may be a communication parameter that applies to the transmission and/or reception of a signal or channel. Numerology, for example, subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame structure, transmission and reception specific filtering operations performed by the receiver in the frequency domain, specific windowing operations performed by the transceiver in the time domain, and/or the like.

A slot may consist of one or more symbols (Orthogonal Frequency Division Multiplexing (OFDM) symbols, Single Carrier Frequency Division Multiple Access (SC-FDMA) symbols, etc.) in the time domain. A slot may be a unit of time based on numerology.

A slot may contain multiple mini-slots. Each minislot may consist of one or more symbols in the time domain. A minislot may also be referred to as a subslot. A minislot may consist of fewer symbols than a slot. A PDSCH (or PUSCH) that is transmitted in time units larger than a minislot may be referred to as PDSCH (or PUSCH) mapping type A. PDSCH (or PUSCH) transmitted using minislots may be referred to as PDSCH (or PUSCH) mapping type B.

Radio frames, subframes, slots, minislots and symbols all represent time units when transmitting signals. Radio frames, subframes, slots, minislots and symbols may be referred to by other corresponding designations.

For example, one subframe may be called a transmission time interval (TTI), multiple consecutive subframes may be called a TTI, and one slot or one minislot may be called a TTI. That is, at least one of the subframe and TTI may be a subframe (1ms) in existing LTE, may be a period shorter than 1ms (eg, 1-13 symbols), or a period longer than 1ms may be Note that the unit representing the TTI may be called a slot, minislot, or the like instead of a subframe.

Here, TTI refers to, for example, the minimum scheduling time unit in wireless communication. For example, in the LTE system, a base station performs scheduling to allocate radio resources (frequency bandwidth, transmission power, etc. that can be used by each user terminal) to each user terminal on a TTI basis. Note that the definition of TTI is not limited to this.

The TTI may be a transmission time unit for channel-encoded data packets (transport blocks), code blocks, codewords, etc., or may be a processing unit for scheduling, link adaptation, etc. Note that when a TTI is given, the time interval (for example, the number of symbols) in which transport blocks, code blocks, codewords, etc. are actually mapped may be shorter than the TTI.

If one slot or one minislot is called a TTI, one or more TTIs (that is, one or more slots or one or more minislots) may be the minimum scheduling time unit. Also, the number of slots (the number of mini-slots) constituting the minimum time unit of the scheduling may be controlled.

A TTI with a time length of 1 ms may be called a normal TTI (TTI in LTE Rel.8-12), normal TTI, long TTI, normal subframe, normal subframe, long subframe, slot, etc. A TTI that is shorter than a regular TTI may also be called a shortened TTI, a short TTI, a partial or fractional TTI, a shortened subframe, a short subframe, a minislot, a subslot, a slot, and so on.

In addition, long TTI (for example, normal TTI, subframe, etc.) may be read as TTI having a time length exceeding 1 ms, and short TTI (for example, shortened TTI, etc.) is less than the TTI length of long TTI and 1 ms. A TTI having a TTI length greater than or equal to this value may be read as a replacement.

A resource block (RB) is a resource allocation unit in the time domain and frequency domain, and may include one or more consecutive subcarriers in the frequency domain. The number of subcarriers included in an RB may be the same regardless of neurology, and may be 12, for example. The number of subcarriers included in an RB may be determined based on neumerology.

Also, the time domain of an RB may include one or more symbols and may be 1 slot, 1 minislot, 1 subframe, or 1 TTI long. One TTI, one subframe, etc. may each consist of one or more resource blocks.

One or more RBs are physical resource blocks (Physical RB: PRB), sub-carrier groups (SCG), resource element groups (REG), PRB pairs, RB pairs, etc. may be called.

In addition, a resource block may be composed of one or more resource elements (Resource Element: RE). For example, 1 RE may be a radio resource region of 1 subcarrier and 1 symbol.

A Bandwidth Part (BWP) (which may also be called a Bandwidth Part) represents a subset of contiguous common resource blocks (RBs) for a neumerology in a carrier. good. Here, the common RB may be identified by an RB index based on the common reference point of the carrier. PRBs may be defined in a BWP and numbered within that BWP.

BWP may include BWP for UL (UL BWP) and BWP for DL (DL BWP). One or more BWPs may be configured in one carrier for a UE.

At least one of the configured BWPs may be active, and the UE may not expect to transmit or receive a given signal/channel outside the active BWP. Note that "cell", "carrier", etc. in the present disclosure may be read as "BWP".

The structures such as radio frames, subframes, slots, minislots and symbols described above are only examples. For example, the number of subframes included in a radio frame, the number of slots per subframe or radio frame, the number of minislots included in a slot, the number of symbols and RBs included in a slot or minislot, the number of Configurations such as the number of subcarriers and the number of symbols in a TTI, symbol length, cyclic prefix (CP) length, etc. can be varied.

The terms "connected," "coupled," or any variation thereof mean any direct or indirect connection or coupling between two or more elements, It can include the presence of one or more intermediate elements between two elements being "connected" or "coupled." Couplings or connections between elements may be physical, logical, or a combination thereof. For example, "connection" may be read as "access". As used in this disclosure, two elements are defined using at least one of one or more wires, cables and printed electrical connections and, as some non-limiting and non-exhaustive examples, in the radio frequency domain. , electromagnetic energy having wavelengths in the microwave and light (both visible and invisible) regions, and the like.

The reference signal can also be abbreviated as Reference Signal (RS), and may also be called Pilot depending on the applicable standard.

The term "based on" as used in this disclosure does not mean "based only on" unless otherwise specified. In other words, the phrase "based on" means both "based only on" and "based at least on."

"Means" in the configuration of each device described above may be replaced with "unit", "circuit", "device", or the like.

Any reference to elements using the "first," "second," etc. designations used in this disclosure does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, references to first and second elements do not imply that only two elements may be employed therein or that the first element must precede the second element in any way.

Where "include," "including," and variations thereof are used in this disclosure, these terms are inclusive, as is the term "comprising." is intended. Furthermore, the term "or" as used in this disclosure is not intended to be an exclusive OR.

In this disclosure, if articles are added by translation, such as a, an, and the in English, the disclosure may include that the nouns following these articles are plural.

The terms "determining" and "determining" used in this disclosure may encompass a wide variety of actions. "Judgement" and "determination" are, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, inquiring (eg, lookup in a table, database, or other data structure), ascertaining as "judged" or "determined", and the like. Also, "judgment" and "determination" are used for receiving (e.g., receiving information), transmitting (e.g., transmitting information), input, output, access (accessing) (for example, accessing data in memory) may include deeming that a "judgment" or "decision" has been made. In addition, "judgment" and "decision" are considered to be "judgment" and "decision" by resolving, selecting, choosing, establishing, comparing, etc. can contain. In other words, "judgment" and "decision" may include considering that some action is "judgment" and "decision". Also, "judgment (decision)" may be read as "assuming", "expecting", "considering", or the like.

In the present disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean that "A and B are different from C". Terms such as "separate," "coupled," etc. may also be interpreted in the same manner as "different."

Although the present disclosure has been described in detail above, it is clear to those skilled in the art that the present disclosure is not limited to the embodiments described in the present disclosure. The present disclosure can be practiced with modifications and variations without departing from the spirit and scope of the present disclosure as defined by the claims. Accordingly, the description of the present disclosure is for illustrative purposes and is not meant to be limiting in any way.

10 Radio communication system 20 E-UTRAN
30NG RAN
100A eNB
100B gNB
110 Radio communication unit 120 RRC processing unit 130 DC processing unit 140 Control unit 200 UE
210 wireless communication unit 220 RRC processing unit 230 DC processing unit 240 control unit 1001 processor 1002 memory 1003 storage 1004 communication device 1005 input device 1006 output device 1007 bus

Claims (6)

1. a receiving unit for receiving a beam from a transmitting/receiving point;
   a control unit that activates the inactive secondary cell group without executing an initial access procedure in response to the generation of uplink data or an instruction from the network;
   The terminal, wherein the control unit detects a failure of the beam before a transmission timing adjustment timer expires, and executes the initial access procedure when the number of failures reaches a specified number.
2. a receiver for receiving a message indicating deactivation of a secondary cell group;
   a control unit that activates the inactive secondary cell group without executing an initial access procedure in response to the generation of uplink data or an instruction from the network;
   The receiving unit receives a transmission timing adjustment command transmitted together with the message,
   The control unit
   starting a transmission timing adjustment timer based on the transmission timing adjustment command;
   A terminal that performs the initial access procedure and activates the inactive secondary cell group if a specific condition is met.
3. a transmitter for transmitting a message requesting activation of an inactive secondary cell group;
   a control unit that executes an initial access procedure or activates an inactive secondary cell group in response to the generation of uplink data or an instruction from the network, or without executing the initial access procedure;
   The terminal, wherein the transmission unit transmits the message including information indicating whether to perform the initial access procedure.
4. receiving a beam from a transmit/receive point;
   activating the inactive secondary cell group without performing an initial access procedure upon occurrence of uplink data or an indication from the network;
   and detecting a failure of the beam before a transmission timing adjustment timer expires, and executing the initial access procedure when the number of failures reaches a specified number.
5. receiving a message instructing deactivation of the secondary cell group;
   activating the inactive secondary cell group without performing an initial access procedure upon occurrence of uplink data or an indication from the network;
   receiving a transmit timing adjustment command transmitted with said message;
   starting a transmission timing adjustment timer based on the transmission timing adjustment command;
   performing the initial access procedure and activating the inactive secondary cell group if certain conditions are met.
6. sending a message requesting activation of the inactive secondary cell group;
   activating an inactive secondary cell group in response to generation of uplink data or an indication from the network, performing an initial access procedure or without performing said initial access procedure;
   and transmitting the message including information indicating whether to perform the initial access procedure.

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