Method for transmitting / receiving uplink signal, and device therefor

Abstract

A method according to an embodiment of the present specification comprises the steps of: receiving configuration information related to a TAG; and transmitting an uplink signal on the basis of uplink time alignment related to a time alignment timer. The TAG includes two TAGs related to a serving cell. Operations for maintenance of the uplink time alignment are performed on the basis that the time alignment timer related to one of the two TAGs expires and the time alignment timer related to the other TAG is running. The operations include a flush operation for at least one HARQ buffer. The at least one HARQ buffer is related to the TAG of the time alignment timer that expired.

Description

Method and device for transmitting and receiving uplink signals

[0001] This specification relates to a method and device for transmitting and receiving an uplink signal.

[0002] Mobile communication systems were developed to provide voice services while ensuring user activity. However, they have expanded beyond voice to include data services. Currently, explosive growth in traffic is leading to resource shortages and users are demanding faster services, necessitating a more advanced mobile communication system.

[0003] Next-generation mobile communication systems must support explosive data traffic growth, dramatically increasing data rates per user, a vastly increased number of connected devices, ultra-low end-to-end latency, and high energy efficiency. To achieve these goals, various technologies are being studied, including dual connectivity, massive multiple input multiple output (MIMO), in-band full duplex, non-orthogonal multiple access (NOMA), super wideband support, and device networking.

[0004] In the existing LTE and NR standards, when setting / instructing uplink timing advance, a single TA value is supported for the Timing Advance Group (TAG) to which a specific cell or group of cells belongs.

[0005] Meanwhile, M-DCI-based Multiple-Transmission and Reception point (M-TRP) operations can be performed in environments where the distance between the UE and different TRPs is large. In such cases, propagation delay differences, slot boundary differences, and inter-UE panel delay differences may occur between target TRPs for uplink transmission within the CC / BWP. This phenomenon can be particularly significant in non-ideal backhaul operations where coordination between TRPs is not achieved.

[0006] To compensate for the timing differences or delays that occur between TRPs as described above, the uplink timing needs to be determined differently for each TRP. To this end, an operation has been agreed upon to associate / correspond TAGs with the TCI states of the unified TCI (e.g., joint TCI state, separate TCI state (DL TCI state or UL TCI state)). To support TRP-specific TAs (i.e., to support two TAs for two TRPs), two TAGs can be configured within a single serving cell.

[0007] In a specific CC / BWP, two TAGs are configured, and operations for maintenance of uplink time alignment (e.g., HARQ buffer flush operations) can be performed based on a Time Alignment Timer (TAT) for each TAG. According to the existing operation, when the TATs for both TAGs have expired, all HARQ buffers for all serving cells belonging to the two TAGs are flushed.

[0008] Meanwhile, the number of HARQ processes per serving cell is limited to a set / defined value (e.g., 16 or 32 for PUSCH), and each HARQ process is associated with a HARQ buffer. Considering the efficiency of operations related to these HARQ processes, a HARQ buffer flush operation must be performed even when the TAT for one of the two TAGs expires.

[0009] However, the existing method does not define the HARQ buffer flush operation and the range of HARQ buffer(s) to which the flush operation applies when some of the two TATs have expired. Considering that uplink transmission operations based on unexpired TATs can be performed, flushing all HARQ buffers in the same manner as when all TATs have expired may be inefficient.

[0010] The purpose of this specification is to propose a method to support HARQ buffer flush operation when the TAT for one of the two TAGs has expired.

[0011] The technical problems to be achieved in this specification are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which this specification pertains from the description below.

[0012] A method performed by a terminal according to one embodiment of the present disclosure includes the steps of receiving configuration information related to a Timing Advance Group (TAG), and transmitting an uplink signal based on uplink time alignment related to a time alignment timer.

[0013] Based on the above configuration information, a time alignment timer associated with the TAG is set. The TAG includes two TAGs associated with a serving cell.

[0014] Based on the time alignment timer associated with one of the two TAGs expiring and the time alignment timer associated with the other TAG being running: operations for maintenance of the uplink time alignment are performed.

[0015] The above operations include a flush operation for at least one HARQ buffer, characterized in that the at least one HARQ buffer is associated with a TAG of the expired time alignment timer.

[0016] The at least one HARQ buffer may be associated with at least one HARQ process identifier (HARQ process ID).

[0017] The at least one HARQ process ID may be associated with a Transmission Configuration Indicator (TCI) state. The TCI state may be associated with the TAG of the expired time alignment timer.

[0018] The HARQ process IDs based on the number of HARQ processes may include i) first HARQ process IDs associated with a first TCI state and ii) second HARQ process IDs associated with a second TCI state. The TCI state may be the first TCI state or the second TCI state.

[0019] The first TCI state may be associated with a first CORESET (COntrol REsource SET) pool index, and the second TCI state may be associated with a second CORESET pool index.

[0020] The above actions may include a clear action associated with the TAG of the expired time alignment timer.

[0021] The TAG of the above expired time alignment timer may be associated with a Transmission Configuration Indicator (TCI, state).

[0022] The above TCI state may be a UL TCI state configured to be associated with a DL TCI state. The DL TCI state may be associated with a configured downlink assignment.

[0023] The TAG of the expired time alignment timer may be associated with a header of a higher layer message. The removal operation may be performed for a configured downlink assignment based on the higher layer message.

[0024] The above removal operation may be related to at least one of i) a configured downlink assignment, ii) a configured uplink grant, and / or iii) a PUSCH resource for semi-persistent CSI reporting.

[0025] A terminal according to another embodiment of the present disclosure includes one or more transceivers, one or more processors, and one or more memories connected to the one or more processors and storing instructions.

[0026] The instructions are characterized in that, based on being executed by the one or more processors, the one or more processors are set to perform all steps of any one of the methods.

[0027] A device according to another embodiment of the present disclosure comprises one or more memories and one or more processors functionally connected to the one or more memories. The one or more memories are characterized in that they store instructions that, based on execution by the one or more processors, cause the one or more processors to perform all steps of any one of the above methods.

[0028] In another embodiment of the present disclosure, one or more non-transitory computer-readable media store instructions, the instructions being executable by one or more processors, characterized in that they cause the one or more processors to perform all steps of any one of the methods.

[0029] A method performed by a base station according to another embodiment of the present disclosure includes the steps of transmitting configuration information related to a Timing Advance Group (TAG) and receiving an uplink signal based on uplink time alignment related to a time alignment timer.

[0030] Based on the above configuration information, a time alignment timer associated with the TAG is set. The TAG includes two TAGs associated with a serving cell.

[0031] Based on the time alignment timer associated with one of the two TAGs expiring and the time alignment timer associated with the other TAG being running: operations for maintenance of the uplink time alignment are performed.

[0032] The above operations include a flush operation for at least one HARQ buffer, characterized in that the at least one HARQ buffer is associated with a TAG of the expired time alignment timer.

[0033] A base station according to another embodiment of the present disclosure includes one or more transceivers, one or more processors, and one or more memories coupled to the one or more processors and storing instructions.

[0034] The instructions are characterized in that they are executed by the one or more processors, and the one or more processors are set to perform all steps of the method.

[0035] In the existing method, HARQ buffers are flushed only after the two time alignment timers for the two TAGs expire. Therefore, if only one TAG's time alignment timer expires, the HARQ buffer(s) associated with that TAG remain unflushed, even though uplink transmission based on that TAG cannot be performed.

[0036] According to an embodiment of the present specification, a flush operation is performed for at least one HARQ buffer based on the expiration of a time alignment timer associated with one of two TAGs, wherein the at least one HARQ buffer is associated with the TAG of the expired time alignment timer.

[0037] Therefore, the efficiency of operations related to the HARQ process can be improved compared to existing operations. Specifically, uplink transmission based on the remaining TAGs associated with unexpired time alignment timers among the two TAGs can be additionally performed based on the HARQ buffer emptied by the flush operation.

[0038] The effects that can be obtained from this specification are not limited to the effects mentioned above, and other effects that are not mentioned can be clearly understood by a person having ordinary skill in the technical field to which this specification belongs from the description below.

[0039] Figure 1 illustrates a MAC RAR according to an embodiment of the present specification.

[0040] FIG. 2 illustrates a Timing Advance Command MAC CE according to an embodiment of the present specification.

[0041] FIG. 3 is a flowchart illustrating a method performed by a terminal according to one embodiment of the present specification.

[0042] FIG. 4 is a flowchart illustrating a method performed by a base station according to another embodiment of the present specification.

[0043] FIG. 5 is a drawing showing the configuration of a first device and a second device according to an embodiment of the present specification.

[0044] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The detailed description set forth below, together with the accompanying drawings, is intended to illustrate exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced. The following detailed description includes specific details to provide a thorough understanding of the present invention. However, one of ordinary skill in the art will appreciate that the present invention may be practiced without these specific details.

[0045] In some cases, to avoid obscuring the concept of the present invention, well-known structures and devices may be omitted or illustrated in block diagram form focusing on the core functions of each structure and device.

[0046] Hereinafter, downlink (DL) refers to communication from a base station to a terminal, and uplink (UL) refers to communication from a terminal to a base station. In downlink, a transmitter may be part of a base station, and a receiver may be part of a terminal. In uplink, a transmitter may be part of a terminal, and a receiver may be part of a base station. A base station may be expressed as a first communication device, and a terminal may be expressed as a second communication device. A base station (BS) may be replaced by terms such as a fixed station, Node B, eNB (evolved-NodeB), gNB (Next Generation NodeB), BTS (base transceiver system), access point (AP: Access Point), network (5G network), AI system, RSU (road side unit), vehicle, robot, drone (Unmanned Aerial Vehicle, UAV), AR (Augmented Reality) device, VR (Virtual Reality) device, etc. In addition, the terminal may be fixed or mobile, and may be replaced with terms such as UE (User Equipment), MS (Mobile Station), UT (user terminal), MSS (Mobile Subscriber Station), SS (Subscriber Station), AMS (Advanced Mobile Station), WT (Wireless terminal), MTC (Machine-Type Communication) device, M2M (Machine-to-Machine) device, D2D (Device-to-Device) device, vehicle, robot, AI module, drone (Unmanned Aerial Vehicle, UAV), AR (Augmented Reality) device, VR (Virtual Reality) device, etc.

[0047] Multi-TRP (Transmission / Reception Point) related operations

[0048] The M-TRP transmission method, in which M TRPs transmit data to one terminal (User equipment, UE), can be broadly divided into two types: eMBB M-TRP transmission, which is a method for increasing the transmission rate, and URLLC M-TRP transmission, which is a method for increasing the reception success rate and reducing latency.

[0049] UL MTRP-URLLC means that multiple TRPs receive the same data / UCI from a UE using different layer / time / frequency resources. For example, TRP 1 receives the same data / UCI from the UE on resource 1, and TRP 2 receives the same data / UCI from the UE on resource 2. Then, the received data / UCI is shared through the backhaul link connected between the TRPs. A UE configured with the UL MTRP-URLLC transmission method transmits the same data / UCI using different layer / time / frequency resources. At this time, the UE is instructed by the base station which Tx beam and which Tx power (i.e., UL TCI state) to use in the layer / time / frequency resource transmitting the same data / UCI. For example, if the same data / UCI is transmitted on resource 1 and resource 2, the UE is instructed on the UL TCI state used on resource 1 and the UL TCI state used on resource 2. This UL MTRP URLLC can be applied to PUSCH / PUCCH.

[0050] SDCI or MDCI based MTRP transmission

[0051] From the perspective of DCI (downlink control information) transmission, the M-TRP (multiple TRP) transmission method can be divided into i) M-DCI (multiple DCI) based M-TRP transmission in which each TRP transmits a different DCI, and ii) S-DCI (single DCI) based M-TRP transmission in which one TRP transmits DCI.

[0052] R16 NR MTRP Transmission

[0053] The R16 NR standard supports S-DCI based MTRP PDSCH and M-DCI based MTRP PDSCH transmission methods.

[0054] R16 M-DCI based MTRP PDSCH

[0055] M-DCI based MTRP PDSCH transmission Each TRP schedules and transmits PDSCH through DCI. That is, TRP 1 transmits PDSCH 1 through DCI 1, and TRP 2 transmits PDSCH 2 through DCI 2. When PDSCH 1 and PDSCH 2 overlap in the same frequency time resource, two PDSCHs are received for the same RE, which increases resource efficiency and increases transmission capacity. To this end, the R16 standard introduces a CORESET pool, which is a group of multiple CORESETs. TRP 1 transmits a PDCCH through a CORESET belonging to CORESET pool 0, and the PDSCH scheduled by the PDCCH is also transmitted by TRP 1. TRP 2 transmits a PDCCH through a CORESET belonging to CORESET pool 1, and the PDSCH scheduled by the PDCCH is also transmitted by TRP 2. PUSCH can also schedule PUSCH transmission to a specific TRP for the UE through a CORESET belonging to each COERSET pool. For PUCCH, some PUCCH resources are scheduled by TRP 1 to receive UCI, and the remaining PUCCH resources are scheduled by TRP 2 to receive UCI. In the case of PUSCH or PUCCH, the channels scheduled / used by each TRP are TDMed with each other, so there is no overlap, and thus no increase in transmission capacity is expected. However, the UE can transmit independent PUSCH / PUCCH for each TRP 1 and 2.

[0056] Additionally, the UE may recognize the PUSCH (or PUCCH) scheduled by the DCI received in different CORESETs (or CORESETs belonging to different CORESET groups) as a PUSCH (or PUCCH) transmitted in different TRPs or as a PUSCH (or PUCCH) of different TRPs. Furthermore, the method for UL transmissions (e.g. PUSCH / PUCCH) transmitted in different TRPs can be equally applied to UL transmissions (e.g. PUSCH / PUCCH) transmitted in different panels belonging to the same TRP.

[0057] The CORESET group ID (or COERSET pool index having the same meaning) described / mentioned in this specification may mean an index / identification information (e.g. ID) for distinguishing a CORESET for each TRP / panel. And the CORESET group may be a group / union of CORESETs distinguished by an index / identification information (e.g. ID) for distinguishing a CORESET for each TRP / panel / the CORESET group ID, etc. For example, the CORESET group ID may be specific index information defined in the CORSET configuration. For example, the CORESET group may be set / indicated / defined by an index defined in the CORESET configuration for each CORESET. And / or CORESET group ID may mean an index / identification information / indicator for distinguishing / identifying between CORESETs set / associated in each TRP / panel, and the CORESET group ID described / mentioned in this specification may be expressed by being replaced with a specific index / specific identification information / specific indicator for distinguishing / identifying between CORESETs set / associated in each TRP / panel. The CORESET group ID, i.e., the specific index / specific identification information / specific indicator for distinguishing / identifying between CORESETs set / associated in each TRP / panel, may be set / indicated through higher layer signaling (e.g. RRC siganling) / L2 signaling (e.g. MAC-CE) / L1 signaling (e.g. DCI), etc. For example, PDCCH detection may be set / indicated to be performed for each TRP / panel in units of the corresponding CORESET group, and / or uplink control information (e.g.CSI, HARQ-A / N, SR) and / or uplink physical channel resources (e.g. PUCCH / PRACH / SRS resources) can be configured / instructed to be managed / controlled separately, and / or HARQ A / N (process / retransmission) for PDSCH / PUSCH, etc. scheduled for each TRP / panel by CORESET group unit can be managed.

[0058] For example, the upper layer parameter ControlResourceSet information element (IE) is used to configure a time / frequency control resource set (CORESET). For example, the control resource set (CORESET) may be related to detection and reception of downlink control information. The ControlResourceSet IE may include a CORESET-related ID (e.g., controlResourceSetID) / an index of a CORESET pool for the CORESET (e.g., CORESETPoolIndex) / time / frequency resource configuration of the CORESET / TCI information related to the CORESET, etc. For example, the index of the CORESET pool (e.g., CORESETPoolIndex) may be set to 0 or 1. In the above description, a CORESET group may correspond to a CORESET pool, and a CORESET group ID may correspond to a CORESET pool index (e.g., CORESETPoolIndex). ControlResourceSet (i.e. CORESET) can be set via higher layer signaling (e.g. RRC).

[0059] <TCI state / beam indication의 의미>

[0060] In addition, in the methods proposed in this specification below, the meaning of using ( / mapping) a specific TCI state (or TCI) when receiving data / DCI / UCI for a certain frequency / time / space resource is as follows.

[0061] For DL, this can mean estimating a channel from DMRS using the QCL type and QCL RS indicated by the DL TCI state in the frequency / time / spatial resources, and receiving / demodulating data / DCI through the estimated channel.

[0062] For UL, this may mean transmitting / modulating DMRS and data / UCI using the Tx beam and / or Tx power indicated by the corresponding UL TCI state in that frequency / time / space resource.

[0063] The above UL TCI state contains Tx beam or Tx power information of the UE, and can be set to the UE through other parameters such as spatial relation info instead of the TCI state. The UL TCI state can be directly indicated in the UL grant DCI, or it can mean spatial relation info of the SRS resource indicated through the SRI field of the UL grant DCI.

[0064] Or it can mean OL Tx power control parameter ( j: index for open loop parameters Po & alpha (maximum 32 parameter value sets per cell), q_d: index of DL RS resource for PL measurement (maximum 4 measurements per cell), l: closed loop power control process index (maximum 2 processes per cell) ) linked to the value indicated through SRI field of UL grant DCI. Or in R17 NR, UL TCI can be indicated using DL grant DCI.

[0065] <TRP 구분 관련 확장 설명>

[0066] For convenience of explanation, the proposed method assumes cooperative transmission / reception between two TRPs. However, it can be expanded to multiple TRP environments with three or more TRPs, as well as multi-panel environments. Different TRPs can be recognized by the UE as having different TCI states (associated with different CORESET pool indices).

[0067] For example, if the UE receives data / DCI using the first TCI state associated with the first CORESET pool index, it means that the data / DCI has been received from TRP1. For example, if the UE transmits data / UCI using the first TCI state associated with the first CORESET pool index, it means that the data / UCI has been transmitted to TRP 1.

[0068] For example, if the UE receives data / DCI using the second TCI state associated with the second CORESET pool index, it means that the data / DCI was received from TRP2. For example, if the UE transmits data / UCI using the second TCI state associated with the second CORESET pool index, it means that the data / UCI was transmitted to TRP 2.

[0069] TA (Timing advance) related procedure

[0070] Transmission of uplink frame number i from a terminal (User Equipment, UE) is earlier than the start of the corresponding downlink frame from that terminal. You have to start earlier.

[0071] The uplink timing (e.g., uplink frame) associated with can be defined as follows:

[0072] Uplink timing

[0073] Uplink frame number for transmission from UE for transmission from the UE) before the start of the corresponding downlink frame from the UE. It should start from .

[0074] - and silver =0 is provided by clause 4.2 of [5, TS 38.213], except for msgA transmission over PUSCH where it must be used.

[0075] - given by clause 4.2 of [5, TS 38.213] is derived from the upper layer parameters TACommon, TACommonDrift, and TACommonDriftVariation (if these parameters are set). Otherwise =0;

[0076] - given by clause 4.2 of [5, TS 38.213] is calculated by the UE based on the UE position and serving-satellite-ephemeris-related higher-layers parameters (if these parameters are set). Otherwise, =0.

[0077] Above is N TA and N TA,offset can be calculated / determined based on N TA and N TA,offset can be set / applied as follows:

[0078] N TA : 1) Set via RAR (Random access response), 2) Set via Timing advance command (MAC-CE)

[0079] N TA,offset : 1) Set specific values ​​for each serving cell, 2) Apply predefined values ​​to each serving cell according to Duplex mode / FR

[0080] Below is the N described above TA,offset and N TA It specifically explains how to set / apply.

[0081] N TA,offset

[0082] Case 1) How to set specific values ​​for each serving cell

[0083] For example, the terminal is N TA,offsetConfiguration information (e.g., ServingCellConfigCommon Information) including information about can be received from the base station. The configuration information can be received based on RRC signaling. Table 1 below exemplifies the configuration information.

[0084]

[0085] Case 2) How to apply predefined values ​​to serving cells according to duplex mode / FR

[0086] For example, the terminal is predefined N according to Duplex mode (TDD / FDD) / FR. TA,offset The value of can be applied to the serving cell. Table 2 below shows N TA,offset exemplifies the value of .

[0087]

[0088] N TA

[0089] Case 1) How to set up using RAR (Random access response)

[0090] For example, in a random access procedure (e.g., a 2-step RACH procedure or a 4-step RACH procedure), the terminal may receive an RAR from the base station. Based on the RAR, N TA can be determined / set. Specifically, the RAR may include a timing advance command. The timing advance command indicates an index value (e.g., index value TA) related to timing adjustment. Based on the index value, N TA can be determined. The above RAR can be based on MAC RAR. This is described below with reference to FIG. 1.

[0091] Figure 1 illustrates a MAC RAR according to an embodiment of the present specification.

[0092] Referring to Figure 1, the MAC RAR may include an R (Reserved bit), a Timing Advance Command, a UL Grant, and a Temporary C-RNTI. The MAC payload of the MAC RAR will be examined in detail below.

[0093] 6.2.3 MAC Payload for Random Access Response

[0094] MAC RAR has a fixed size as shown in Figure 6.2.3-1 and consists of the following fields:

[0095] - R: Reserved bit, set to 0;

[0096] - TI: If two TAGs are configured for the Serving Cell where the Random Access procedure is performed, this field indicates which of the two TAGs the Timing Advance Command applies to. A field set to 0 indicates the first TAG ID, and a field set to 1 indicates the second TAG ID. If two TAGs are not configured for the Serving Cell where the Random Access procedure is performed, the R bit is present instead;

[0097] - Timing Advance Command: The Timing Advance Command field indicates the index value TA used to control the amount of timing adjustment that the MAC entity should apply in TS 38.213 [6]. The size of the Timing Advance Command field is 12 bits;

[0098] - UL Grant: The Uplink Grant field indicates the resources used for the uplink in TS 38.213[6]. The size of the UL Grant field is 27 bits;

[0099] - Temporary C-RNTI: The Temporary C-RNTI field indicates a temporary identifier used by the MAC entity during random access. The size of the Temporary C-RNTI field is 16 bits.

[0100] The MAC RAR is octet aligned.

[0101] Below, we examine transmission timing adjustments based on the Timing advance command.

[0102] 4.2 Adjusting transmission timing

[0103] The UE is informed of the timing advance offset for the serving cell by n-TimingAdvanceOffset for the serving cell. The values ​​can be provided. If the UE provides two coresetPoolIndex values ​​0 and 1 for the first and second CORESET for the serving cell, or does not provide a coresetPoolIndex value for the first CORESET and provides a coresetPoolIndex value 1 for the second CORESET, the UE can provide the first and second coresetPoolIndex values. You can get the values: first and second The values ​​are provided by n-TimingAdvanceOffset and n-TimingAdvanceOffset2 for transmissions of the TCI state associated with the first and second CORESET, respectively. The UE selects the first CORESET for transmissions based on the spatial domain filters corresponding to the TCI state associated with the physCellId of the serving cell. In addition to the value, a second one is provided for transmissions based on spatial domain filters corresponding to the physCellId for the serving cell and the TCI states associated with other physCellIds. You can get the values. First and second The values ​​correspond to the first and second joint TCI states provided by the dl-OrJointTCI-StateList or the first and second UL TCI states provided by the ul-TCI-State-List and the first and second TAGs [11, TS 38.321] having an association indicated by the tag-Id-ptr. If the UE is not provided with n-TimingAdvanceOffset for the serving cell, the UE defaults to the timing advance offset for the serving cell as described in [10, TS 38.133]. Decide.

[0104] When two UL carriers are configured for a serving cell in a UE, the same timing advance offset value is applied to both carriers for transmission in the serving cell associated with the same TAG. This applies. The UE has two I don't expect the values ​​to apply.

[0105] When a terminal receives a timing advance command for a TAG, the terminal expects the same for all serving cells within the TAG. Based on the value and the received timing advance command, the terminal adjusts the uplink timing for PUSCH / SRS / PUCCH transmission for all serving cells in the TAG. Here, the uplink timing for PUSCH / SRS / PUCCH transmission is the same for all serving cells in the TAG.

[0106] For a band having synchronous contiguous intra-band EN-DC in a band combination having a maximum transmission timing difference requirement that is not applicable as described in Note 1 of Table 7.5.3-1 of [10, TS 38.133], if the UE indicates ul-TimingAlignmentEUTRA-NR as 'mandatory' and the uplink transmission timing based on the timing adjustment indications for the TAG from the MCG and the TAG from the SCG are determined by the UE to be different, the UE adjusts the transmission timing for PUSCH / SRS / PUCCH transmissions for all serving cell portions of the band having synchronous contiguous intra-band EN-DC based on the timing adjustment indications for the TAG from the serving cell of the MCG in the band. The UE is not expected to transmit PUSCH / SRS / PUCCH in one CG if it overlaps in time, even partially, with a random access preamble transmitted in another CG.

[0107] For SCS, the timing advance command for TAG is Indicates a change in uplink timing relative to the current uplink timing for the TAG by a multiple of . The starting timing of the random access preamble is described in [4, TS 38.211].

[0108] For random access response or for cell transition command T_A for absolute timing advance command MAC CE or TAG, the timing advance command [11, TS 38.321] = with index values ​​of 0, 1,2, ..., 3846 The values ​​represent the time alignment amount of TAG where SCS is 2^μ15kHz. am. is defined in [4, TS 38.211] and relates to the SCS of the first uplink transmission from the UE after receiving a random access response or an absolute timing advance command MAC CE or a cell switching command.

[0109] In other cases, the timing advance command for TAG [11, TS 38.321], Is The index values ​​of = 0, 1, 2,.. 0, 1, 2,..., 63 are currently value, to new value Indicates that it is adjusted to . Here, for SCS of 2^μ15kHz, am.

[0110] If a UE has multiple active UL BWPs in the same TAG, including UL BWPs on two UL carriers of the serving cell, the timing advance command value is associated with the largest SCS among the multiple active UL BWPs, as described in Section 12. The SCS applicable to the UL BWP with the lowest SCS is The value may be rounded to match the timing advance granularity for the UL BWP with the lowest SCS while meeting the timing advance accuracy requirements of [10, TS 38.133].

[0111] Adjusting the value by a positive or negative amount means advancing or delaying the uplink transmission time for the TAG by the corresponding amount, respectively.

[0112] For transmissions other than PUSCH scheduled by a timing advance command received in uplink slot n and a RAR UL grant or fallbackRAR UL grant as described in Section 8.2A or 8.3, or PUCCH with HARQ-ACK information in response to a SuccessRAR as described in Section 8.2A, the timing of the corresponding uplink transmission is adjusted by the uplink slot It applies from the beginning. Here is the PDSCH processing time for UE processing capability 1 when additional PDSCH DM-RS is configured. is the duration of the symbols (msec), corresponds to the PUSCH preparation time for UE processing capability 1. The time in msec of the symbols is [6, TS 38.214], is the maximum timing advance value (in msec) that can be provided by the 12-bit TA command field, is the number of slots per subframe, is a subframe period of 1 msec, and Here is provided by cellSpecificKoffset is provided by the Differential Koffset MAC CE command [11, TS 38.321]. Otherwise, if not provided, =0 or =0. For the minimum SCS among the SCSs of all UL BWPs configured for all uplink carriers in the TAG and the SCSs of all DL BWPs configured for the corresponding downlink carriers. class is determined. If μ=0, the UE is [6, TS 38.214]. For slot n and the minimum SCS among the SCSs of all UL BWPs configured for all uplink carriers in the TAG, This is decided. is determined with respect to the minimum SCS among the SCSs of all UL BWPs configured for all uplink carriers in the TAG and the SCSs of all configured initial UL BWPs provided by initialUplinkBWP. Uplink slot n is =0, the last slot among the uplink slot(s) overlapping with the PDSCH reception slot(s), where the PDSCH provides a timing advance command. is defined in [4, TS 38.211].

[0113] If the UE changes the active UL BWP between the time it receives the timing advance command and the time it applies the adjustment to the corresponding uplink transmission timing, the UE determines the timing advance command value based on the SCS of the new active UL BWP. If the UE changes the active UL BWP after applying the uplink transmission timing adjustment, the UE assumes the same absolute timing advance command value before and after the active UL BWP change.

[0114] If the received downlink timing changes and is not compensated or only partially compensated by uplink timing adjustment without timing advance command as described in [10, TS 38.133], the UE changes N_TA accordingly. If the UE operates based on two TAGs in the active UL BWP of the serving cell, the UE expects that the difference between the first downlink timing associated with the first TAG and the second downlink timing associated with the second TAG will not be larger than the CP length for the active UL BWP, unless the UE indicates larger-thanCP-capability. If the UE indicates XYZ_capability, is provided with SRS-autonomousTAupdate [10, TS 38.133], and transmits SRS according to the configuration by SRS-PosResourceSet in SRS-PosRRC-InactiveConfig-ValidityArea in RRC_INACTIVE state, the UE shall change N_TA accordingly during cell reselection. can autonomously update; otherwise, if SRS-autonomousTAupdate is not provided to the UE, the UE shall update the last serving cell before the dedicated RRC connection is released. maintains [11, TS 38.321].

[0115] For the operation of a single TAG in a serving cell, if two adjacent slots overlap due to a TA command, the duration of the later slot is reduced compared to the earlier slot. The UE may transmit PUSCH or PUCCH during the actual transmission time window. [6, TS 38.214]. If a UE is not provided with the activated STx2PofMDCI and operates based on two TAGs in the serving cell, the UE shall not expect transmissions associated with different TAGs to overlap, unless the UE indicates XYZ. If the UE indicates XYZ, the UE shall reduce the duration of later transmissions using the first TAG to avoid overlapping with earlier transmissions using the second TAG.

[0116] Case 2) How to set using Timing advance command (MAC-CE)

[0117] For example, N TA can be set / determined based on MAC-CE. Specifically, N TA can be determined based on the Timing Advance Command MAC CE. The Timing Advance Command MAC CE may include a timing advance command. N based on the timing advance command TA Since the decision is the same as that described in Case 1, duplicate explanation is omitted (see Table 5). The Timing Advance Command MAC CE is described below with reference to FIG. 2.

[0118] FIG. 2 illustrates a Timing Advance Command MAC CE according to an embodiment of the present specification.

[0119] Referring to FIG. 2, the Timing Advance Command MAC CE may include a TAG ID and a Timing Advance Command. The payload of the Timing Advance Command MAC CE will be examined in detail below.

[0120] 6.1.3.4 Timing Advance Command MAC CE

[0121] Timing Advanced Commands MAC CE is identified by a MAC subheader with an LCID as specified in Table 6.2.1-1.

[0122] It has a fixed size and consists of a single octet defined as follows (Figure 6.1.3.4-1):

[0123] - TAG Identity (TAG ID): This field indicates the TAG ID of the addressed TAG. A TAG containing an SpCell has TAG ID 0. The field length is 2 bits;

[0124] - Timing Advance Command: This field indicates an index value TA (0, 1, 2...63) used to control the amount of timing adjustment that the MAC entity should apply (as specified in TS 38.213 [6]). The field is 6 bits long.

[0125] 6.1.3.4a Absolute Timing Advance Command MAC CE

[0126] An Absolute Timing Advance Command MAC CE is identified by a MAC subheader with an eLCID as specified in Table 6.2.1-1b.

[0127] It has a fixed size and consists of two octets defined as follows (Figure 6.1.3.4a-1):

[0128] - Timing Advance Command: This field indicates the index value TA used to control the amount of timing adjustment that the MAC entity should apply in TS 38.213 [6]. The field size is 12 bits;

[0129] - TI: If two TAGs are configured for the SpCell, this field indicates which of the two TAGs the Timing Advance Command applies to. A field set to 0 indicates the first TAG ID, and a field set to 1 indicates the second TAG ID. If two TAGs are not configured for the SpCell, the R bit is present instead;

[0130] - R: Reserved bit, set to 0.

[0131] TAG (Timing advance group)

[0132] A Timing Advance Group (TAG) is a group of serving cells that use the same Timing Advance value. Table 3 below illustrates the definition of a TAG and the associated configuration information.

[0133]

[0134] Procedure

[0135] Below, we will look specifically at the operations for uplink time alignment.

[0136] 5.2 Uplink Time Alignment Management

[0137] RRC configures the following parameters to manage UL time alignment:

[0138] - timeAlignmentTimer (per TAG) that controls the period during which the MAC entity considers the serving cell belonging to the relevant TAG to be uplink time aligned.

[0139] - inactivePosSRS-TimeAlignmentTimer, which controls the period during which the MAC entity considers positioning SRS transmissions in RRC_INACTIVE as uplink time aligned in section 5.26;

[0140] - cg-SDT-TimeAlignmentTimer, which controls the period during which the MAC entity considers uplink transmissions for CG-SDT to be uplink time aligned.

[0141] The MAC entity must:

[0142] 1> When a Timing Advance Command MAC CE is received and the TAG is maintained with NTA (defined in TS 38.211 [8]) indicated:

[0143] 2> Apply Timing Advance Command to the displayed TAG.

[0144] 2> If there is a Positioning SRS transmission in progress in RRC_INACTIVE as in section 5.26:

[0145] 3> Start or restart the inactivePosSRS-TimeAlignmentTimer associated with the indicated TAG.

[0146] 2> If a triggered CG-SDT procedure is in progress as in section 5.27:

[0147] 3> Start or restart the cg-SDT-TimeAlignmentTimer associated with the indicated TAG.

[0148] 2> Otherwise:

[0149] 3> Start or restart the timeAlignmentTimer associated with the indicated TAG.

[0150] 1> When a Random Access Response message for a Serving Cell belonging to a TAG or a Timing Advance Command is received in the MSGB for an SpCell:

[0151] 2> If the Random Access Preamble is not selected by the MAC entity during contention-based Random Access Preamble:

[0152] 3> Apply Timing Advance Command to this TAG.

[0153] 3> Start or restart the timeAlignmentTimer associated with this TAG.

[0154] 2> Otherwise, if the timeAlignmentTimer associated with this TAG is not running:

[0155] 3> Apply Timing Advance Command to this TAG.

[0156] 3> Start the timeAlignmentTimer associated with this TAG.

[0157] 3> If the contention resolution is deemed unsuccessful as described in Section 5.1.5, or

[0158] 3> If the Contention Resolution for the SI request is considered successful as described in Section 5.1.5, then after transmitting HARQ feedback for the MAC PDU containing the UE Contention Resolution Identity MAC CE:

[0159] 4> Stop the timeAlignmentTimer associated with this TAG.

[0160] 3> If the contention resolution is deemed unsuccessful as described in Section 5.1.5:

[0161] 4> If a CG-SDT procedure triggered as in Section 5.27 is in progress:

[0162] 5> Set the NTA value to the value before applying the received Timing Advance Command as in TS 38.211 [8].

[0163] 3> If the Contention Resolution for the Random Access procedure is deemed successful while the CG-SDT procedure is in progress:

[0164] 4> Stop the timeAlignmentTimer associated with this TAG.

[0165] 4> Start or restart the cg-SDT-TimeAlignmentTimer associated with this TAG.

[0166] 3> If Contention Resolution for Random Access procedure is considered successful while SRS transmission is in progress in RRC_INACTIVE:

[0167] 4> Start or restart the inactivePosSRS-TimeAlignmentTimer associated with this TAG.

[0168] 2>If not:

[0169] 3> Ignore the received timing advance command.

[0170] 1> When an Absolute Timing Advance Command is received in response to an MSGA transmission containing a C-RNTI MAC CE as specified in Section 5.1.4a:

[0171] 2> Apply Timing Advance Command to PTAG.

[0172] 2> If there is a Positioning SRS transmission in progress in RRC_INACTIVE as in section 5.26:

[0173] 3> Start or restart the inactivePosSRS-TimeAlignmentTimer associated with the indicated TAG.

[0174] 2> If the CG-SDT procedure is in progress:

[0175] 3> Start or restart the cg-SDT-TimeAlignmentTimer associated with PTAG.

[0176] 2> Otherwise:

[0177] 3> Start or restart the timeAlignmentTimer associated with the PTAG.

[0178] 1> When an indication to stop the inactivePosSRS-TimeAlignmentTimer is received from the upper layer:

[0179] 2> Stop inactivePosSRS-TimeAlignmentTimer.

[0180] 1> When an indication to start the inactivePosSRS-TimeAlignmentTimer is received from the upper layer:

[0181] 2> Start or restart the inactivePosSRS-TimeAlignmentTimer.

[0182] 1> When an upper layer instruction to start cg-SDT-TimeAlignmentTimer is received:

[0183] 2> Start cg-SDT-TimeAlignmentTimer.

[0184] 1> If an instruction is received from the upper layer to stop cg-SDT-TimeAlignmentTimer:

[0185] 2> cg-SDT-TimeAlignmentTimer is considered expired.

[0186] 1> When an instruction is received from the upper layer to start the TimeAlignmentTimer associated with the PTAG:

[0187] 2> Start the TimeAlignmentTimer associated with the PTAG.

[0188] 1> When timeAlignmentTimer expires:

[0189] 2> If timeAlignmentTimer is associated with PTAG:

[0190] 3> Flush all HARQ buffers for all serving cells.

[0191] 3> If configured, notify RRC to release PUCCH for all serving cells.

[0192] 3> If configured, notify RRC to release SRS for all serving cells.

[0193] 3> Delete all configured downlink assignments and configured uplink grants.

[0194] 3> Delete all PUSCH resources for semi-persistent CSI reporting.

[0195] 3> All running timeAlignmentTimers are considered expired.

[0196] 3> Maintain the NTA of all TAGs (as defined in TS 38.211 [8]).

[0197] 2> Otherwise, if timeAlignmentTimer is associated with a STAG, then for all serving cells belonging to this TAG:

[0198] 3> Flush all HARQ buffers.

[0199] 3> If configured, notify RRC to release PUCCH.

[0200] 3> Notifies RRC to release SRS if configured.

[0201] 3> Delete all configured downlink assignments and configured uplink grants.

[0202] 3> Delete all PUSCH resources for semi-persistent CSI reporting.

[0203] 3> Maintain the NTA of this TAG (as defined in TS 38.211 [8]).

[0204] 1> When inactivePosSRS-TimeAlignmentTimer expires:

[0205] 2> Notifies RRC to release positioning SRS for RRC_INACTIVE configuration(s).

[0206] 1> When cg-SDT-TimeAlignmentTimer expires:

[0207] 2> Clear all configured uplink authorizations.

[0208] 2> If no PDCCH addressed to the C-RNTI of the MAC entity is received after the initial transmission of the CG-SDT containing the CCCH message:

[0209] 3> The ongoing CG-SDT procedure is considered to have been concluded.

[0210] 3> Notifies upper layers of the expiration of cg-SDT-TimeAlignmentTimer.

[0211] 2> Flush all HARQ buffers.

[0212] 2> Maintain the NTA of this TAG (as defined in TS 38.211 [8]).

[0213] If a MAC entity stops uplink transmission for a SCell because the maximum uplink transmission timing difference between TAGs of the MAC entity or the maximum uplink transmission timing difference between TAGs of any MAC entity of the UE exceeds, the MAC entity considers the timeAlignmentTimer associated with the SCell to have expired.

[0214] The MAC entity shall not perform any uplink transmissions on the serving cell except for random access preamble and MSGA transmissions unless the timeAlignmentTimer associated with the TAG to which the serving cell belongs is running, unless a CG-SDT procedure is in progress, or unless an SRS transmission in RRC_INACTIVE is in progress as per clause 5.26.

[0215] Additionally, if the timeAlignmentTimer associated with PTAG is not running, the CG-SDT procedure is not in progress, and no SRS transmission is in progress in RRC_INACTIVE as in Section 5.26, the MAC entity shall not perform any uplink transmissions on any serving cell except for random access preamble and MSGA transmissions for SpCell.

[0216] The MAC entity shall not perform any uplink transmissions except for Random Access Preamble and MSGA transmissions when the cg-SDT-TimeAlignmentTimer is not running during an ongoing CG-SDT procedure as triggered in Section 5.27. The MAC entity shall not perform any uplink transmissions except for Random Access Preamble and MSGA transmissions when the inactivePosSRS-TimeAlignmentTimer is not running during a procedure for SRS transmission in RRC_INACTIVE as in Section 5.26.

[0217] The above-mentioned content can be applied in combination with the methods proposed in this specification, which will be described later, or can be supplemented to clarify the technical characteristics of the methods proposed in this specification. The methods described below are distinguished for convenience of explanation, and it is understood that certain components of one method may be substituted for or combined with other methods.

[0218] According to 3GPP standards up to NR Rel-17, the timing advance (TA) setting for uplink transmissions between base stations and terminals to compensate for propagation delay between the base station and terminals can be performed via higher-layer signaling. Furthermore, the concept / definition of a timing advance group (TAG) allows for separate TA settings and management for specific groups of cells.

[0219] Currently, support for multiple TA values ​​within a specific cell has not been provided. However, enhancements are planned to allow for setting / indicating multiple (two) TA values ​​for a specific CC / BWP, considering scenarios where the distances between different target TRPs differ significantly during M-TRP UL transmission.

[0220] In this case, it is necessary to discuss how the base station will configure / instruct the terminal to configure / instruct multiple TA values, and / or how the connection between the multiple TA values ​​and the terminal UL channel / RS will be performed. As described in the Rel-18 MIMO WID objective (RP-213598) in Table 4 below, the configuration of TA values ​​for multi-DCI (M-DCI) based M-TRP operation is being considered.

[0221]

[0222] Here, the above TA (TA value) may be based on the description of FIG. 2 and the contents described in the TA (Timing advance) related procedure described above.

[0223] In RAN1 and RAN2 standards prior to Rel-18, the base station must specify N for the terminal TA value. TA Wow NTA,offset It is managed through the value called . The base station is N TA can be set as follows: i) N via RAR MAC CE TA or ii) N through TA command MAC CE (Timing Advance Command MAC CE) TA In addition, the base station utilizes the concept of TAG (Timing Advance Group) to set up to 4 TAGs per terminal for a specific cell or cell combination, and N for each TAG. TA You can update / manage values.

[0224] A scenario that supports two TA values ​​as described in WID is an M-DCI based M-TRP operation. In an M-DCI based M-TRP operation, each TRP can be distinguished based on a CORESET pool index associated with a CORESET(s) existing in a BWP. Based on the CORESET pool index, each TRP can be distinguished as i) a TRP performing DL transmission (i.e., PDCCH, PDSCH) or / and ii) a target TRP for UL transmission. For example, CORESETs 0 and 1 with CORESET pool index 0 can correspond to TRP 1, and CORESETs 2 and 3 with CORESET pool index 1 can correspond to TRP 2.

[0225] Meanwhile, in Rel-18 MIMO, an agreement was reached regarding two TAs, as shown in Table 5 below.

[0226]

[0227] As described above, it was discussed that two TAGs can be set up to manage two TA values ​​in one serving cell, and it was also agreed that the reference timing to apply the TA values ​​managed in each TAG would support two DL reference timings in one serving cell.

[0228] In addition, it was agreed that the PDCCH ordered CFRA mechanism would be utilized for the above two TA acquisition, and discussions were held on the uplink resources regarding which uplink transmission the two acquired TAs (TAGs) should be utilized for and the connection relationship between the two TAs. As a result, it was agreed to associate the TAG ID with the UL and / or joint TCI state (via RRC signaling) for the association of the two TAGs set within a serving cell with the UL channel / RS as agreed upon above. The remaining issue is how to perform TRP / TAG-specific TAT management.

[0229] Specifically, as two TAGs are configured in a specific CC / BWP of a terminal, a Time Alignment Timer (TAT) can be managed for each TAG. According to the legacy TAT management operation, an out-of-synch operation can be performed for all cells of the terminal as a specific TAT is related to a PTAG / STAG, or an out-of-synch operation can be performed for all cells related to the corresponding STAG. This out-of-synch operation can include the operations according to Table 6 below. Specifically, the out-of-synch operation can include a flush operation of a HARQ buffer, a release operation for PUCCH / SRS, a clear operation for configured DL / UL assignments, etc.

[0230] However, in Rel-18, when two TATs are managed within a specific CC / BWP, ambiguity arises as to what actions a UE should take when a TAT associated with a specific TAG expires. In particular, issues arise regarding i) which HARQ buffers to flush, ii) which PUCCH / SRS resources to release, and iii) which PUSCH resources, including configured DL assignments, UL grants, and semi-pesrsistent CSI reporting, to clear.

[0231]

[0232] This document proposes a method for managing a TAG-specific TAT (Time Alignment Timer) of a terminal when multiple TAs are supported for a specific CC / BWP(s) of the terminal.

[0233] In this specification, ' / ' can be interpreted as 'and', 'or', or 'and / or' depending on the context.

[0234] Problem 1

[0235] When two TAGs are configured in a specific CC / BWP of a terminal and a Time Alignment Timer (TAT) is managed for each TAG, ambiguity arises as to which HARQ process number / ID (hereinafter referred to as HARQ ID) within the CC / BWP should a flush operation be performed upon expiration of a specific TAT. Below, we will examine in detail a method for resolving Problem 1.

[0236] Proposal 1

[0237] A method of setting / connecting / mapping a HARQ (Hybrid Automatic Repeat reQuest) ID and a specific TAG or / and CORESET pool index may be considered. This is described in detail below.

[0238] HARQ IDs may be determined based on a maximum number (e.g., nrofHARQ-Processes) set for a specific CC / BWP of the terminal. For example, in the case of a terrestrial network, up to 16 HARQ IDs may be determined. For example, in the case of a non-terrestrial network, up to 32 HARQ IDs may be determined. One or more HARQ IDs may be configured / connected / mapped with a specific TAG and / or CORESET pool index. For example, the one or more HARQ IDs may be associated with a TCI state. The TCI state may be associated with a specific TAG. The TCI state may be associated with one CORESET pool index.

[0239] The above setup / connection / mapping can be performed by upper layer signaling (e.g., RRC, MAC) of the base station.

[0240] For example, HARQ IDs 0 to 7 can be associated with TAG ID 0 or / and CORESET pool index 0, and HARQ IDs 8 to 15 can be associated with TAG 1 or / and CORESET pool index 1. As a specific example, HARQ IDs 0 to 7 can be associated with the first TCI state (associated with TAG ID 0), and HARQ IDs 8 to 15 can be associated with the second TCI state (associated with TAG ID 1).

[0241] For example, a HARQ ID may be set / determined / assigned based on a TAG or / and a CORESET pool index. That is, a HARQ ID may not be set / determined for a specific CC / BWP. Specifically, a HARQ ID may be set / assigned separately for a specific TAG or / and a CORESET pool index. Accordingly, an explicit link relationship between a TAG or / and a CORESET pool index and a HARQ ID may be established. In this case, only the HARQ ID associated with a specific CORESET pool index may be indicated based on the 4-bit HARQ process number field of the DCI (e.g., the 5-bit HARQ process number field in the case of NTN) related / associated with the specific CORESET pool index. That is, the interpretation of the HARQ process number field of a specific DCI may vary depending on which CORESET pool index and which CORESET the DCI is transmitted in. Accordingly, up to 16 HARQ IDs can be utilized for each CORESET pool, based on up to 4-bit fields associated with each CORESET pool. For NTN, up to 32 HARQ IDs can be utilized for each CORESET pool, based on up to 5-bit fields.

[0242] For example, it may be assumed that only a maximum of 16 HARQ IDs (up to 32 HARQ IDs for NTN) are utilized within a specific CC / BWP as per the existing legacy standard. In this case, a method of dividing the HARQ IDs into CORESET pools and utilizing them may be considered. Specifically, 8 HARQ IDs (16 HARQ IDs for NTN) may be utilized in each CORESET pool. According to this embodiment, the HARQ process number field of the DCI can be configured with 3 bits (4 bits for NTN) to save the DCI payload.

[0243] According to the above embodiments, when the TAT of a specific TAG among the two TAGs set in the CC / BWP expires, the terminal may perform a flush operation for the HARQ ID set / connected / mapped with the corresponding TAG ID (or / and the CORESET pool index implicitly associated / related with the corresponding TAG). That is, in the above example, when the TAT for TAG ID 0 expires, the terminal may perform a flush operation for HARQ IDs 0 to 7.

[0244] According to the above-described embodiments, the following effects are obtained.

[0245] If a UE enters an out-of-synch phase with a particular TAG / TRP due to TAT expiration associated with that TAG / TRP, the UE may (explicitly) flush the HARQ ID associated with that TAG / TRP without ambiguity.

[0246] Problem 2

[0247] When two TAGs are configured in a specific CC / BWP of a UE and a Time Alignment Timer (TAT) is managed separately for each TAG, ambiguity may arise regarding the actions performed upon expiration of a specific TAT. For example, it may be unclear which PUCCH / SRS resources within the CC / BWP the UE should perform a release for. For example, it may be unclear which configured DL assignments and UL grants within the CC / BWP the UE should clear. For example, it may be unclear which PUSCH resources for semi-pesrsistent CSI reporting within the CC / BWP the UE should clear. Below, we will examine in detail the method for resolving Problem 2.

[0248] Proposal 2

[0249] When the TAT of a specific TAG among the two TAGs set in the CC / BWP expires, the above-described release / clear operation can be performed as follows.

[0250] For example, a release / clear operation may be performed on UL resources (e.g., PUCCH / SRS, configured UL grant, PUSCH including semi-pesrsistent CSI reporting) related / associated with the TCI state associated with the specific TAG. The TCI state associated with the specific TAG may mean a TCI state in which the ID of the specific TAG is set via RRC signaling. The TCI state may include a DL / UL joint TCI state and / or a UL TCI state.

[0251] The UL resources related / associated with the above TCI state may refer to UL resources (i.e., PUCCH / PUSCH / SRS resources) for which the TCI state is configured / activated / indicated by RRC / MAC CE / DCI. The TCI state indicated by DCI may include the first / second indicated TCI state related to the first / second CORESETPoolIndex in the extended unified TCI framework for Rel-18 M-TRP operation.

[0252] For example, when the TAT of a specific TAG among two TAGs configured in CC / BWP expires, a clear operation may be performed on DL resources (e.g., configured DL assignment) related / associated with the TCI state associated with the specific TAG. The TCI state associated with the specific TAG may mean a TCI state in which the ID of the specific TAG is configured through RRC signaling. The TCI state may include a DL / UL joint TCI state and / or a UL TCI state.

[0253] The DL resources related / associated with the above TCI state may refer to DL resources (i.e., PDCCH / PDSCH / CSI-RS resources) for which the TCI state is set / activated / indicated by RRC / MAC CE / DCI. To support the above operation, the following methods may be considered.

[0254] In one embodiment, in separate DL / UL TCI state setup, a TAG ID (associated with two TAs) may be set (via RRC / MAC CE signaling) for the DL TCI state.

[0255] In one embodiment, in setting up separate DL / UL TCI states, the connection relationship between the DL TCI state and the UL TCI state can be defined / established by upper layer signaling (e.g., RRC, MAC). That is, since the TAG ID is not set for the DL TCI state, the above-described clear operation can be performed depending on which TAG ID is set for the UL TCI state that is in a connection relationship with the corresponding DL TCI state.

[0256] Specifically, when the TAT associated with a specific TAG expires, a DL TCI state may be determined based on the UL TCI state in which the corresponding TAG ID is set. The DL TCI state may be a DL TCI state related / associated with the UL TCI state. DL resources related / associated with the DL TCI state may be cleared.

[0257] The connection relationship between the DL TCI state and the UL TCI state may include a connection relationship between DL / UL TCI states. Specifically, two DL TCI states and two UL TCI states (for M-TRP purposes) may be updated based on DCI for separate DL / UL TCI state management. The connection relationship may be defined / established between the two DL TCI states and the two UL TCI states. For example, the connection relationship may be defined / established as follows.

[0258] The first indicated DL TCI state can be linked to the first indicated UL TCI state. The second indicated DL TCI state can be linked to the second indicated UL TCI state.

[0259] According to the above-described embodiments, the following effects are obtained.

[0260] When a UE enters an out-of-synch phase with a specific TAG / TRP due to TAT expiration associated with that TAG / TRP, the UE can (explicitly) release / clear the DL / UL resources associated with that TAG / TRP without ambiguity.

[0261] In one embodiment, the following method may be considered as another example of a method for linking DL resources and TAG IDs of Proposal 2.

[0262] Rather than defining the association of TAG or / and DL / UL TCI state and DL physical channel(s) / signal(s) from a layer 1 perspective, a method of distinguishing 'DL assignment' from a layer 2 or higher layer perspective may be considered.

[0263] Specifically, the base station can perform the following operations when performing DL assignment for PDSCH scheduling. The base station can include the TRP ID, CORESET pool index, and / or TAG ID in the header (e.g., MAC, PDCP, RLC header, etc.) of the user plain DL data packet, which is a higher layer message. Through this, the UE can determine which TRP / TAG ID a specific DL assignment is associated / related with. Based on the association between the DL assignment and the TRP / TAG ID, the UE can perform a clear operation on the 'configured downlink assignments' related to the TAG / TRP when the TAT of the specific TAG expires.

[0264] Considering the previously defined operations (e.g., Table 6), the operations of the above proposals 1 and 2 can be applied as follows 1) to 3).

[0265] 1) When the configuration of two TAGs within a specific CC / BWP is PTAG + STAG, and the TAT associated with the PTAG expires, the UE can operate as follows. Since the PTAG has expired, the UE can perform out-of-sync operations for all serving cells. Specifically, the UE can operate based on the following Table 7.

[0266]

[0267] 2) When the configuration of two TAGs within a specific CC / BWP is PTAG + PTAG, and the TAT associated with the PTAG expires, the UE can operate as follows. Since another PTAG within the CC / BWP is maintained, the UE does not perform out-of-sync operation for all serving cells. That is, the UE performs out-of-sync operation for some DL / UL resources. Specifically, the UE can operate based on Table 8.

[0268]

[0269] 3) When the configuration of two TAs within a specific CC / BWP is PTAG + STAG / STAG + STAG, and the TAT associated with STAG expires, the UE can operate as follows. Since other TAGs within the CC / BWP are maintained, the UE does not perform out-of-sync operations for all serving cells associated with the STAG. That is, the UE performs out-of-sync operations for some DL / UL resources. Specifically, the UE can operate based on Table 9.

[0270]

[0271] For example, the above proposals 1 and 2 can be extended to a baseline feature that clearly shows a one-to-one correspondence between the COREST pool index and the TAG ID during two TA operations. According to the baseline feature, the terminal expects that the UL / joint TCI state of a UL signal / channel associated with one CORESET Pool Index corresponds to one TAG. As a specific example, considering the correlation between the TAG and the TCI state, the configuration / connection / mapping of proposal 1 can be performed based on the TCI state associated with one CORESET Pool Index.

[0272] For example, the above proposals 1 and 2 can be extended to an optional feature that manages two TAGs for a specific CORESET pool index. According to the optional feature, a terminal can support and report that the UL / joint TCI state of a UL signal / channel associated with one CORESET Pool Index corresponds to both TAGs.

[0273] The above embodiments may be operated by a combination of specific embodiments.

[0274] An example of a terminal (or base station) operation based on at least one of the embodiments described above (e.g., at least one of Proposals 1 to 2 and an additional embodiment) is as follows.

[0275] 1) The terminal (base station) receives (transmits) settings related to two TAGs (two TAs) within a specific serving cell.

[0276] The above settings may include a connection relationship between a TAG ID and a UL resource.

[0277] Two TA acquisitions (using PDCCH ordered CFRA) for each TAG can be performed before / after the above setup.

[0278] 2) The terminal (base station) receives (transmits) a message scheduling uplink transmission related to the two TAGs.

[0279] The above message may be based on an RRC message, MAC CE or DCI.

[0280] 3) The terminal (base station) transmits (receives) an uplink signal based on the above message.

[0281] 4) Based on the expiration of the TAT associated with a specific TAG among the two TAGs, an out-of-synch operation (e.g., TRP-level or cell-level operation) based on the proposals 1 to 2 and additional embodiments may be performed.

[0282] The above terminal / base station operations are only an example, and each operation (or step) is not necessarily required, and depending on the terminal / base station implementation method, an operation may be omitted or added when the TAT related to a specific TAG among the two TAGs of the terminal according to the above-described embodiments expires.

[0283] In terms of implementation, the operations of the base station / terminal according to the embodiments described above (e.g., operations based on at least one of Proposals 1 to 2 and additional embodiments) can be processed by the device of FIG. 5 described below (e.g., processor (110, 210) of FIG. 5).

[0284] In addition, the operations of the base station / terminal according to the above-described embodiments (e.g., operations based on at least one of proposals 1 to 2 and additional embodiments) may be stored in a memory (e.g., 140, 240 of FIG. 5) in the form of commands / programs (e.g., instructions, executable codes) for driving at least one processor (e.g., 110, 210 of FIG. 5).

[0285] The embodiments described below are specifically described with reference to FIGS. 3 and 4 in terms of the operation of the terminal and base station. The methods described below are distinguished for convenience of explanation, and it is understood that some components of one method may be substituted for or combined with some components of another method.

[0286] FIG. 3 is a flowchart illustrating a method performed by a terminal according to one embodiment of the present specification.

[0287] Referring to FIG. 3, a method performed by a terminal according to one embodiment of the present specification includes a step of receiving configuration information related to a TAG (S310) and a step of transmitting an uplink signal based on uplink time alignment (S320).

[0288] In step S310, the terminal receives configuration information related to a Timing Advance Group (TAG) from the base station. A time alignment timer related to the TAG may be set based on the configuration information. For example, the TAG may include multiple TAGs (e.g., two TAGs associated with a serving cell). The time alignment timer may be set for each of the multiple TAGs. For example, the configuration information may be based on a higher layer parameter TAG-Config.

[0289] In S320, the terminal transmits an uplink signal to the base station based on uplink time alignment associated with the time alignment timer.

[0290] For example, the uplink signal may be a physical uplink shared channel (PUSCH), a physical uplink control channel (PUCCH), or a sounding reference signal (SRS).

[0291] For example, the TAG may include two TAGs associated with a serving cell.

[0292] Based on the expiration of the time alignment timer associated with one of the two TAGs and the running of the time alignment timer associated with the other TAG: operations for maintenance of the uplink time alignment may be performed. The operations may be based on at least one of Table 8, Proposals 1 and 2. This will be described in detail below.

[0293] In one embodiment, the operations may include a flush operation for at least one HARQ buffer. This embodiment may be based on Proposal 1. The at least one HARQ buffer may be associated with a TAG of the expired time alignment timer.

[0294] For example, the at least one HARQ buffer may be associated with at least one HARQ process identifier (HARQ process ID).

[0295] For example, the at least one HARQ process ID may be associated with a Transmission Configuration Indicator (TCI) state. The TCI state may be associated with the TAG of the expired time alignment timer.

[0296] For example, HARQ process IDs based on the number of HARQ processes (e.g., 16) may include i) first HARQ process IDs associated with a first TCI state (e.g., HARQ process ID 0 to 7) and ii) second HARQ process IDs associated with a second TCI state (e.g., HARQ process ID 8 to 15). The TCI state may be the first TCI state or the second TCI state. The first TCI state may be associated with a first CORESET (COntrol REsource SET) pool index. The second TCI state may be associated with a second CORESET pool index.

[0297] In one embodiment, the above operations may include a clear operation associated with the TAG of the expired time alignment timer. This embodiment may be based on Proposal 2.

[0298] For example, the TAG of the expired time alignment timer may be associated with a Transmission Configuration Indicator (TCI) state. As a specific example, the TCI state may be a UL TCI state configured to be associated with a DL TCI state. The DL TCI state may be associated with a configured downlink assignment.

[0299] For example, the TAG of the expired time alignment timer may be associated with the header of a higher layer message. The removal operation may be performed for a configured downlink assignment based on the higher layer message. The higher layer message may refer to the user plain DL data packet described above.

[0300] For example, the removal operation may be associated with at least one of i) a configured downlink assignment, ii) a configured uplink grant, and / or iii) a PUSCH resource for semi-persistent CSI reporting.

[0301] The operations based on S310 to S320 described above can be implemented by the device of FIG. 5. For example, the terminal (200) can control one or more transceivers (230) and / or one or more memories (240) to perform the operations based on S310 to S320.

[0302] The embodiments described below are specifically described in terms of base station operation.

[0303] S410 to S420 described below correspond to S310 to S320 described in FIG. 3. Considering the above correspondence, redundant descriptions are omitted. That is, the specific description of the base station operation described below may be replaced with the description / example of FIG. 3 corresponding to the operation.

[0304] FIG. 4 is a flowchart illustrating a method performed by a base station according to another embodiment of the present specification.

[0305] Referring to FIG. 4, a method performed by a base station according to another embodiment of the present specification includes a step of transmitting configuration information related to TAG (S410) and a step of receiving an uplink signal based on uplink time alignment (S420).

[0306] In step S410, the base station transmits configuration information related to a Timing Advance Group (TAG) to the terminal. A time alignment timer related to the TAG may be set based on the configuration information. For example, the TAG may include multiple TAGs (e.g., two TAGs associated with a serving cell). The time alignment timer may be set for each of the multiple TAGs. For example, the configuration information may be based on a higher layer parameter TAG-Config.

[0307] In S420, the base station receives an uplink signal from the terminal based on uplink time alignment associated with the time alignment timer.

[0308] The operations based on S410 to S420 described above can be implemented by the device of FIG. 5. For example, the base station (100) can control one or more transceivers (130) and / or one or more memories (140) to perform the operations based on S410 to S420.

[0309] Hereinafter, a device to which an embodiment of the present specification can be applied (a device that implements a method / operation according to an embodiment of the present specification) is described with reference to FIG. 5.

[0310] FIG. 5 is a drawing showing the configuration of a first device and a second device according to an embodiment of the present specification.

[0311] The first device (100) may include a processor (110), an antenna unit (120), a transceiver (130), and a memory (140).

[0312] The processor (110) performs baseband-related signal processing and may include a higher layer processing unit (111) and a physical layer processing unit (115). The higher layer processing unit (111) may process operations of a MAC layer, an RRC layer, or higher layers. The physical layer processing unit (115) may process operations of a PHY layer. For example, when the first device (100) is a base station device in base station-terminal communication, the physical layer processing unit (115) may perform uplink reception signal processing, downlink transmission signal processing, etc. For example, when the first device (100) is a first terminal device in terminal-to-terminal communication, the physical layer processing unit (115) may perform downlink reception signal processing, uplink transmission signal processing, sidelink transmission signal processing, etc. In addition to performing baseband-related signal processing, the processor (110) may also control the overall operation of the first device (100).

[0313] The antenna unit (120) may include one or more physical antennas, and when it includes multiple antennas, it may support MIMO transmission and reception. The transceiver (130) may include an RF (Radio Frequency) transmitter and an RF receiver. The memory (140) may store information processed by the processor (110), and software, an operating system, applications, etc. related to the operation of the first device (100), and may also include components such as a buffer.

[0314] The processor (110) of the first device (100) may be configured to implement the operation of the base station in the base station-to-terminal communication (or the operation of the first terminal device in the terminal-to-terminal communication) in the embodiments described in the present disclosure.

[0315] The second device (200) may include a processor (210), an antenna unit (220), a transceiver (230), and a memory (240).

[0316] The processor (210) performs baseband-related signal processing and may include a higher layer processing unit (211) and a physical layer processing unit (215). The higher layer processing unit (211) may process operations of a MAC layer, an RRC layer, or higher layers. The physical layer processing unit (215) may process operations of a PHY layer. For example, when the second device (200) is a terminal device in base station-terminal communication, the physical layer processing unit (215) may perform downlink reception signal processing, uplink transmission signal processing, etc. For example, when the second device (200) is a second terminal device in terminal-to-terminal communication, the physical layer processing unit (215) may perform downlink reception signal processing, uplink transmission signal processing, sidelink reception signal processing, etc. In addition to performing baseband-related signal processing, the processor (210) may also control the overall operation of the second device (210).

[0317] The antenna unit (220) may include one or more physical antennas, and when it includes multiple antennas, it may support MIMO transmission and reception. The transceiver (230) may include an RF transmitter and an RF receiver. The memory (240) may store information processed by the processor (210), software, an operating system, applications, etc. related to the operation of the second device (200), and may also include components such as a buffer.

[0318] The processor (210) of the second device (200) may be configured to implement operations of the terminal in base station-to-terminal communication (or operations of the second terminal device in terminal-to-terminal communication) in the embodiments described in the present disclosure.

[0319] In the operation of the first device (100) and the second device (200), the same explanations given for the base station and the terminal (or the first terminal and the second terminal in the terminal-to-terminal communication) in the examples of the present disclosure may be applied, and redundant explanations are omitted.

[0320] Here, the wireless communication technology implemented in the device (100, 200) of the present disclosure may include not only LTE, NR, and 6G, but also Narrowband Internet of Things (NB-IoT) for low-power communication. For example, NB-IoT technology may be an example of LPWAN (Low Power Wide Area Network) technology, and may be implemented in standards such as LTE Cat NB1 and / or LTE Cat NB2, and is not limited to the above-described names.

[0321] Additionally or alternatively, the wireless communication technology implemented in the device (100, 200) of the present disclosure may perform communication based on LTE-M technology. For example, LTE-M technology may be an example of LPWAN technology and may be called by various names such as eMTC (enhanced Machine Type Communication). For example, LTE-M technology may be implemented by at least one of various standards such as 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-BL (non-Bandwidth Limited), 5) LTE-MTC, 6) LTE Machine Type Communication, and / or 7) LTE M, and is not limited to the above-described names.

[0322] Additionally or alternatively, the wireless communication technology implemented in the device (100, 200) of the present disclosure may include at least one of ZigBee, Bluetooth, and Low Power Wide Area Network (LPWAN) that take low-power communication into account, and is not limited to the above-described names. For example, ZigBee technology can create personal area networks (PANs) related to small / low-power digital communication based on various standards such as IEEE 802.15.4, and may be called by various names.

Claims

1. In a method performed by a terminal, A step of receiving configuration information related to a Timing Advance Group (TAG), wherein a time alignment timer related to the TAG is set based on the configuration information; and A step of transmitting an uplink signal based on uplink time alignment associated with the above time alignment timer; comprising: The above TAG includes two TAGs associated with the serving cell, Based on the time alignment timer associated with one of the two TAGs expiring and the time alignment timer associated with the other TAG being running: Operations for maintenance of the above uplink time alignment are performed, The above operations include a flush operation for at least one HARQ buffer, A method characterized in that said at least one HARQ buffer is associated with a TAG of said expired time alignment timer.

2. In paragraph 1, A method characterized in that at least one HARQ buffer is associated with at least one HARQ process identifier (HARQ process ID).

3. In paragraph 2, At least one of the above HARQ process IDs is associated with a Transmission Configuration Indicator (TCI) state, A method characterized in that the TCI state is related to the TAG of the expired time alignment timer.

4. In paragraph 3, HARQ process IDs based on the number of HARQ processes include i) first HARQ process IDs associated with the first TCI state and ii) second HARQ process IDs associated with the second TCI state, A method characterized in that the TCI state is the first TCI state or the second TCI state.

5. In paragraph 4, A method characterized in that the first TCI state is related to the first CORESET (COntrol REsource SET) pool index, and the second TCI state is related to the second CORESET pool index.

6. In paragraph 1, A method characterized in that the above operations include a clear operation associated with the TAG of the expired time alignment timer.

7. In paragraph 6, A method characterized in that the TAG of the expired time alignment timer is associated with a Transmission Configuration Indicator (TCI, state).

8. In paragraph 7, The above TCI state is a UL TCI state set to be associated with the DL TCI state, A method characterized in that the above DL TCI state is related to a configured downlink assignment.

9. In paragraph 6, The TAG of the above expired time alignment timer is related to the header of the higher layer message, A method characterized in that the removal operation is performed for a configured downlink assignment based on the upper layer message.

10. In paragraph 6, A method characterized in that the above removal operation is related to at least one of i) a configured downlink assignment, ii) a configured uplink grant, and / or iii) a PUSCH resource for semi-persistent CSI reporting.

11. In the terminal, One or more transmitters and receivers; one or more processors; and One or more memories connected to said one or more processors and storing instructions, A terminal characterized in that the instructions are set to cause the one or more processors to perform all steps of the method according to any one of claims 1 to 10, based on being executed by the one or more processors.

12. In a device comprising one or more memories and one or more processors functionally connected to the one or more memories, A device characterized in that said one or more memories store instructions that cause said one or more processors to perform all steps of a method according to any one of claims 1 to 10, based on being executed by said one or more processors.

13. In one or more non-transitory computer-readable media storing instructions, One or more non-transitory computer-readable media characterized in that the instructions executable by one or more processors cause the one or more processors to perform all steps of the method according to any one of claims 1 to 10.

14. In a method performed by a base station, A step of transmitting configuration information related to a Timing Advance Group (TAG), wherein a time alignment timer related to the TAG is set based on the configuration information; and A step of receiving an uplink signal based on uplink time alignment associated with the above time alignment timer; comprising: The above TAG includes two TAGs associated with the serving cell, Based on the time alignment timer associated with one of the two TAGs expiring and the time alignment timer associated with the other TAG being running: Operations for maintenance of the above uplink time alignment are performed, The above operations include a flush operation for at least one HARQ buffer, A method characterized in that said at least one HARQ buffer is associated with a TAG of said expired time alignment timer.

15. At the base station, One or more transmitters and receivers; one or more processors; and One or more memories connected to said one or more processors and storing instructions, A base station characterized in that the instructions are set to cause the one or more processors to perform all steps of the method according to claim 14, based on the instructions being executed by the one or more processors.

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