Method and apparatus for handling retransmissions on configured uplink granted resources

Abstract

A user equipment (UE) includes a processor coupled to one or more non-transitory computer-readable media. The processor is configured to execute the computer-executable instructions to determine that the transmission of a media access control MAC protocol data unit PDU using a first physical uplink shared channel PUSCH resource was not successfully performed, the first PUSCH resource is associated with a first configuration authorization CG configuration, the first PUSCH resource is associated with a first hybrid automatic repeat request HARQ process, and the MAC PDU is acquired for the first HARQ process; receive a second CG configuration; determine that a second PUSCH resource associated with the second CG configuration can be used for another transmission, the second PUSCH resource is associated with a second HARQ process; if one or more specific conditions are met, determine that the second PUSCH resource can be used to transmit the MAC PDU; and when it is determined that the second PUSCH resource can be used to transmit the MAC PDU, transmit the MAC PDU on the second PUSCH resource.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims the benefit of and priority to U.S. Provisional Patent Application Serial No. 62 / 909,950, filed on October 3, 2019, entitled “Method and Apparatus to Handle Uplink Transmission in Unlicensed Spectrum” (hereinafter “‘950 Provisional”). The disclosure of the ‘950 Provisional is hereby incorporated by reference into this disclosure in its entirety. Technical Field

[0003] The present disclosure relates to wireless communications, and more particularly, to methods and apparatus for handling (re)transmissions on configured uplink grant resources. Background Art

[0004] The 3rd Generation Partnership Project (3GPP) has agreed to include New Radio (NR) based unlicensed spectrum access as one of the work items (WI) for Release 16. This WI specifies NR enhancements for a single global solution framework for accessing unlicensed spectrum, enabling NR to operate in unlicensed bands (e.g., 5 GHz and 6 GHz bands) while taking into account regional regulatory requirements. Unlicensed NR (NR-U) design should enable fair coexistence between deployed Wireless Fidelity (Wi-Fi) generations and NR-U, NR-U and Long Term Evolution - License Assisted Access (LTE-LAA), different NR-U systems, etc.

[0005] NR has defined Type 1 and Type 2 configuration grant mechanisms. These two configuration grant mechanisms are also included in NR-U operation. For retransmissions of HARQ processes that were originally transmitted via configured uplink grant resources, retransmissions via the same configured uplink grant resources and retransmissions of resources scheduled via UL grants are supported. However, there is a need for further improvement in the art. Summary of the invention

[0006] The present disclosure relates to methods and apparatus for SL operations.

[0007] According to a first aspect of the present disclosure, a user equipment (UE) is provided, wherein the UE includes one or more non-transitory computer-readable media including computer-executable instructions contained therein, and at least one processor coupled to the one or more non-transitory computer-readable media. The at least one processor is configured to execute computer-executable instructions to determine that transmission of a media access control MAC protocol data unit (PDU) using a first physical uplink shared channel (PUSCH) resource was not successfully performed, the first PUSCH resource being associated with a first configuration authorization CG configuration, the first PUSCH resource being associated with a first hybrid automatic repeat request (HARQ) process, and the MAC PDU being acquired for use in the first HARQ process; receiving a second CG configuration; determining that a second PUSCH resource associated with the second CG configuration is available for another transmission, the second PUSCH resource being associated with a second HARQ process; determining that the second PUSCH resource is available for transmission of the MAC PDU if one or more specific conditions are met; and transmitting the MAC PDU on the second PUSCH resource when it is determined that the second PUSCH resource is available for transmission of the MAC PDU, the one or more specific conditions including one or more of: the second PUSCH resource available for the other transmission is used for a new transmission; and the second PUSCH resource is scheduled on the same bandwidth part (BWP) as the first PUSCH resource.

[0008] In an embodiment of the first aspect, the one or more specific conditions further include at least one of the following conditions: the first HARQ process and the second HARQ process have the same HARQ process identification ID; the second PUSCH resource and the first PUSCH resource have the same size; the second CG configuration and the first CG configuration are the same; and the second PUSCH resource is a prioritized PUSCH resource.

[0009] In another embodiment of the first aspect, the at least one processor is further configured to execute the computer executable instructions to: if the one or more specific conditions are not met, determine that the second PUSCH resource is not available for transmitting the MAC PDU; and when it is determined that the second PUSCH resource is not available for transmitting the MAC PDU, generate a new MAC PDU and transmit the new MAC PDU on the second PUSCH resource.

[0010] In another embodiment of the first aspect, the second PUSCH resource available for the other transmission is used for the new transmission if at least one of the following conditions is met: the configuration authorization timer for the second HARQ process is not running; and repetition is not configured for the second CG configuration.

[0011] In another embodiment of the first aspect, the transmission of the MAC PDU using the first PUSCH resource associated with the first CG configuration is not successfully performed because the first PUSCH resource associated with the first CG configuration is de-prioritized.

[0012] In another embodiment of the first aspect, when the transmission of the MAC PDU using the first PUSCH resource associated with the first CG configuration is not successfully performed, the MAC PDU is retained in a HARQ buffer associated with the first HARQ process.

[0013] In another embodiment of the first aspect, the transmission of the MAC PDU using the first PUSCH resource associated with the first CG configuration is not successfully performed due to UL listen-before-talk (LBT) failure.

[0014] In another embodiment of the first aspect, the at least one processor is further configured to execute the computer executable instructions to: increase the LBT counter based on the UL LBT failure; and when the LBT counter reaches a threshold configured on the BWP, the first PUSCH resource is scheduled on the BWP, and the BWP belongs to a primary secondary cell PSCell, transmit a secondary cell group SCG failure report.

[0015] In another implementation of the first aspect, when consistent UL LBT failure is detected on all BWPs configured with physical random access channel PRACH resources on the PSCell, the SCG failure report is transmitted.

[0016] In another embodiment of the first aspect, the SCG failure report includes a failure type information element IE, and the failure type IE indicates the failure type as SCG-LBT failure.

[0017] According to the second aspect of the present disclosure, a method for wireless communication performed by a UE is provided. The method includes determining that the transmission of a media access control MAC protocol data unit PDU using a first physical uplink shared channel PUSCH resource is not successfully performed, the first PUSCH resource is associated with a first configuration authorization CG configuration, the first PUSCH resource is associated with a first hybrid automatic repeat request HARQ process, and the MAC PDU is acquired for the first HARQ process; receiving a second CG configuration; determining that a second PUSCH resource associated with the second CG configuration can be used for another transmission, the second PUSCH resource is associated with a second HARQ process; if one or more specific conditions are met, determining that the second PUSCH resource can be used to transmit the MAC PDU; and when determining that the second PUSCH resource can be used to transmit the MAC PDU, transmitting the MAC PDU on the second PUSCH resource, the one or more specific conditions including one or more: the second PUSCH resource that can be used for the other transmission is used for a new transmission; and the second PUSCH resource and the first PUSCH resource are scheduled on the same bandwidth part BWP.

[0018] In an embodiment of the second aspect, the one or more specific conditions further include at least one of the following conditions: the first HARQ process and the second HARQ process have the same HARQ process identification ID; the second PUSCH resource and the first PUSCH resource have the same size; the second CG configuration and the first CG configuration are the same; and the second PUSCH resource is a prioritized PUSCH resource.

[0019] In another embodiment of the second aspect, the method also includes determining that the second PUSCH resource is not available for transmitting the MAC PDU if the one or more specific conditions are not met; and when it is determined that the second PUSCH resource is not available for transmitting the MAC PDU, generating a new MAC PDU and transmitting the new MAC PDU on the second PUSCH resource.

[0020] In another embodiment of the second aspect, the second PUSCH resource available for the other transmission is used for the new transmission if at least one of the following conditions is met: the configuration authorization timer for the second HARQ process is not running; and repetition is not configured for the second CG configuration.

[0021] In another embodiment of the second aspect, the transmission of the MAC PDU using the first PUSCH resource associated with the first CG configuration is not successfully performed because the first PUSCH resource associated with the first CG configuration is de-prioritized.

[0022] In another embodiment of the second aspect, when the transmission of the MAC PDU using the first PUSCH resource associated with the first CG configuration is not successfully performed, the MAC PDU is retained in a HARQ buffer associated with the first HARQ process.

[0023] In another embodiment of the second aspect, the transmission of the MAC PDU using the first PUSCH resource associated with the first CG configuration is not successfully performed due to UL listen-before-talk (LBT) failure.

[0024] In another embodiment of the second aspect, the method also includes: increasing the LBT counter based on the UL LBT failure; and when the LBT counter reaches a threshold configured on the BWP, the first PUSCH resource is scheduled on the BWP, and the BWP belongs to the primary secondary cell PSCell, transmitting a secondary cell group SCG failure report.

[0025] In another embodiment of the second aspect, when a consistent UL LBT failure is detected on all BWPs configured with physical random access channel PRACH resources on the PSCell, the SCG failure report is transmitted.

[0026] In another embodiment of the second aspect, the SCG failure report includes a failure type information element IE, and the failure type IE indicates the failure type as SCG-LBT failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Various aspects of the present disclosure are best understood from the following detailed disclosure when read with the accompanying drawings. Various features are not drawn to scale. The dimensions of various features may be arbitrarily increased or decreased for clarity of discussion.

[0028] Figure 1 The configuration of the authorization timer operation in NR is shown.

[0029] Figure 2 is a diagram showing a method for processing retransmissions on configured uplink granted resources according to an exemplary embodiment of the present disclosure.

[0030] Figure 3 is a diagram showing conditional processing of retransmissions on configured uplink granted resources according to an exemplary embodiment of the present disclosure.

[0031] Figure 4 is a diagram showing a timer-based processing of retransmissions on configured uplink granted resources according to an exemplary embodiment of the present disclosure.

[0032] Figure 5 is a diagram showing processing of retransmission on configured uplink granted resources based on state variables according to an exemplary embodiment of the present disclosure.

[0033] Figure 6 is a diagram showing counter-based processing of retransmissions on configured uplink grant resources according to an exemplary embodiment of the present disclosure.

[0034] Figure 7 is a flowchart of a method for LBT recovery and reporting process performed by a UE according to an exemplary embodiment of the present disclosure.

[0035] Figure 8 is a diagram illustrating UE behavior when an LBT recovery process is initiated according to an exemplary embodiment of the present disclosure.

[0036] Fig. 9 is a block diagram of a node for wireless communication according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0037] The following disclosure contains specific information related to exemplary embodiments of the present disclosure. The accompanying drawings and the detailed disclosures therewith are directed to exemplary embodiments. However, the present disclosure is not limited to these exemplary embodiments. Other variations and embodiments of the present disclosure will occur to those skilled in the art.

[0038] Unless otherwise indicated, similar or corresponding components in the drawings may be indicated by similar or corresponding reference numerals. Furthermore, the drawings and illustrations are generally not drawn to scale and are not intended to correspond to actual relative sizes.

[0039] For the purpose of consistency and ease of understanding, similar features (although not shown in some examples) are indicated by the same numbers in the exemplary drawings. However, the features in different embodiments may be different in other aspects, and therefore should not be narrowly limited to the features shown in the drawings.

[0040] The terms "in one embodiment" or "in some embodiments" may refer to one or more of the same or different embodiments, respectively. The term "coupled" is defined as connected directly or indirectly through intermediate components, and is not necessarily limited to physical connections. The term "comprising" may mean "including but not necessarily limited to," and specifically indicates open inclusion or membership in the disclosed combinations, groups, series, and equivalents. The expression "at least one of A, B, and C" or "at least one of the following: A, B, and C" means "only A, or only B, or only C, or any combination of A, B, and C."

[0041] The terms "system" and "network" can be used interchangeably. The term "and / or" is used only to describe the association relationship of associated objects, and indicates that three relationships can exist, so that A and / or B can indicate that A exists alone, A and B exist at the same time, or B exists alone. The character " / " usually indicates that the associated objects are in an "or" relationship.

[0042] For the purpose of non-limiting explanation, specific details such as functional entities, technologies, protocols, standards, etc. are set forth to provide an understanding of the disclosed technology. In other examples, detailed disclosures of well-known methods, technologies, systems, and architectures are omitted to avoid obscuring the disclosure with unnecessary details.

[0043] Those skilled in the art will recognize that any (one or more) disclosed network functions or (one or more) algorithms can be implemented by hardware, software, or a combination of software and hardware. The disclosed functions can correspond to modules, which can be software, hardware, firmware, or any combination thereof.

[0044] Software implementations may include computer executable instructions stored on a computer readable medium such as a memory or other type of storage device. One or more microprocessors or general-purpose computers with communication processing capabilities may be programmed with corresponding executable instructions and execute the disclosed (one or more) network functions or (one or more) algorithms.

[0045] The microprocessor or general-purpose computer may be composed of an application-specific integrated circuit (ASIC), a programmable logic array, and / or one or more digital signal processors (DSP). Although some of the disclosed embodiments relate to software installed and executed on computer hardware, alternative embodiments as firmware or hardware or a combination of hardware and software are also within the scope of the present disclosure. Computer-readable media may include, but are not limited to, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, compact disc (CD) read-only memory (CD-ROM), cassettes, magnetic tapes, disk storage devices, or any other equivalent medium capable of storing computer-readable instructions.

[0046] A radio communication network architecture, such as a Long Term Evolution (LTE) system, an LTE-Advanced (LTE-A) system, an LTE-Pro system, or a 5G NR New Radio Access Network (NR Radio Access Network, RAN) may typically include at least one base station (BS), at least one UE, and one or more optional network components that provide a connection to the network. The UE may communicate with a network, such as a Core Network (CN), an Evolved Packet Core (EPC) network, an Evolved Universal Terrestrial Radio Access Network (E-UTRAN), a Next-Generation Core (NGC), a 5G Core (5G Core, 5GC), or the Internet via a Radio Access Network (RAN) established by one or more BSs.

[0047] UE may include but is not limited to a mobile base station, a mobile terminal or device or a user communication radio terminal. For example, UE may be a portable radio device, including but not limited to a mobile phone, a tablet computer, a wearable device, a sensor or a personal digital assistant (PDA) with wireless communication capabilities. UE may be configured to receive and send signals to one or more cells in the RAN over an air interface.

[0048] The BS may be configured to provide communication services according to at least one of the following Radio Access Technologies (RATs): Worldwide Interoperability for Microwave Access (WiMAX), GSM (commonly referred to as 2G), GERAN, General Packet Radio Service (GPRS), UMTS based on basic Wideband Code Division Multiple Access (W-CDMA) (commonly referred to as 3G), High-Speed ​​Packet Access (HSPA), LTE, LTE-A, evolved LTE (eLTE) connected to 5GC, NR (commonly referred to as 5G), and / or LTE-A Pro. However, the scope of the present disclosure is not limited to these protocols.

[0049] The BS may include, but is not limited to, a node B (NB) in a Universal Mobile Telecommunication System (UMTS), an evolved node B (eNB) in LTE or LTE-A, a radio network controller (RNC) in UMTS, a base station controller (BSC) in a global system for mobile communications (GSM) / GSM enhanced GSM Evolution Data Rates RAN (GERAN), a next-generation eNB (ng-eNB) in an Evolved Universal Terrestrial Radio Access (E-UTRA) BS connected to a 5GC, a next-generation Node B (gNB) in a 5G-RAN, or any other device capable of controlling radio communications and managing radio resources within a cell. The BS may serve one or more UEs through a radio interface.

[0050] The BS may be operable to provide radio coverage to a specific geographical area using a plurality of cells forming a RAN. The BS may support the operation of the cells. Each cell may be operable to provide service to at least one UE within its radio coverage area.

[0051] The BS may be operable to provide radio coverage to a specific geographic area using a plurality of cells forming a RAN. The BS may support the operation of cells. Each cell may be operable to provide services to at least one UE within its radio coverage. More specifically, each cell (commonly referred to as a serving cell) may provide services to one or more UEs within its radio coverage (e.g., each cell schedules downlink (DL) resources and optional uplink (UL) resources to at least one UE within its radio coverage for DL ​​and optional UL packet transmission). The BS may communicate with one or more UEs in a radio communication system through a plurality of cells.

[0052] The cell can allocate sidelink (SL) resources to support proximity service (ProSe) or vehicle-to-everything (V2X) services. Each cell may have a coverage area that overlaps with other cells.

[0053] As discussed previously, the frame structure of NR supports flexible configuration to accommodate various next-generation (e.g., 5G) communication requirements, such as eMBB, mMTC, and URLLC, while meeting high reliability, high data rate, and low latency requirements. The Orthogonal Frequency-Division Multiplexing (OFDM) technology in the 3rd Generation Partnership Project (3GPP) can be used as a baseline for the NR waveform. Scalable OFDM parameter sets such as adaptive subcarrier spacing, channel bandwidth, and cyclic prefix (CP) can also be used.

[0054] Two coding schemes are considered for NR, specifically, Low-Density Parity-Check (LDPC) and polar codes. Coding scheme adaptability can be configured based on channel conditions and / or service applications.

[0055] When the transmission time interval (TTI) of a single NR frame includes DL transmission data, protection period and UL transmission data, the corresponding parts of DL transmission data, protection period and UL transmission data can be configured based on the network dynamics of NR. SL resources can also be provided in the NR frame to support ProSe services or V2X services.

[0056] Given below are illustrative descriptions of some selected terms used in this disclosure.

[0057] Primary Cell (PCell): For dual connectivity (DC) operation, PCell is a Master Cell Group (MCG) cell, operating on the primary frequency, where the UE performs an initial connection establishment procedure or initiates a connection re-establishment procedure.

[0058] Primary SCG Cell (PSCell): For DC operation, PSCell is the Secondary Cell Group (SCG) cell where the UE performs random access when performing reconfiguration using the Sync procedure.

[0059] Special cell: For DC operation, the term special cell (SpCell) refers to the PCell of the MCG or the PSCell of the SCG, otherwise the term special cell refers to the PCell.

[0060] Secondary cell: A cell that provides additional radio resources on top of a special cell for a UE configured with carrier aggregation (CA).

[0061] Serving cell: For a UE in RRC_CONNECTED without CA / DC configured, there is only one serving cell, which can be called the primary cell. For a UE in RRC_CONNECTED with CA / DC configured, the term "serving cell" can be used to refer to a cell group including the SpCell and all secondary cells.

[0062] Listen before talk (LBT) is a feature available in Wi-Fi that allows coexistence with other Wi-Fi nodes. LBT is a mechanism by which a device applies a Clear Channel Assessment (CCA) before using a channel. The 3rd Generation Partnership Project (3GPP) chose to specify a conservative LBT scheme similar to that used by Wi-Fi nodes to ensure that Licensed Assisted Access (LAA) coexists with Wi-Fi. LAA uses carrier aggregation in the DL to combine LTE in unlicensed spectrum (e.g., 5GHz) with LTE in licensed bands. In NR, when operating on unlicensed spectrum, LBT is required before any transmission is made.

[0063] In NR Release-15, the Configuration Grant Timer was introduced. This timer is maintained per HARQ Process ID. Whenever the UE performs a specific (re)transmission (e.g. on resources indicated by an uplink grant addressed to the C-RNTI and the identified HARQ process is configured for a configuration uplink grant configuration, on configured UL resources or on resources indicated by an uplink grant addressed to the CS-RNTI), the Configuration Grant Timer corresponding to the HARQ Process ID of the (re)transmission is (re)started. Figure 1 FIG. 2 shows the configuration of the authorization timer operation in NR. Figure 1 As shown, when the configuration grant timer is running, the UE is prohibited from performing new transmissions (e.g., generating new TBs for transmission) on the configured uplink grant resources (e.g., PUSCH) using the same HARQ process ID as the configuration grant timer. For example, the latest PUSCH resource cannot be used for new transmissions.

[0064] In unlicensed spectrum, the UE can perform channel access before performing a transmission to ensure that no other device occupies the channel where the transmission is intended to be performed. For the channel access mechanism in NR-U operation, the LTE-LAA LBT mechanism can be adopted as a baseline for the 5GHz band and a design starting point for the 6GHz band. At least for bands where it cannot be guaranteed (for example, by regulation) that Wi-Fi does not exist, LBT can be performed in units of 20MHz. In general, there are 4 LBT categories. An introduction to each LBT category can be found below. For NR-U operation, the UE can perform LBT using one of the 4 LBT categories before performing UL transmissions for different transmissions in the COT (defined below) and different channels / signals to be transmitted. Specifically, the UE can perform LBT using different LBT categories before performing RACH, PUCCH, PUSCH, and SRS transmissions.

[0065] Category 1: Transmission immediately after a short switching gap

[0066] This can be used for the transmitter to transmit immediately after the switching gap within the COT. More specifically, the switching gap from reception to transmission is to accommodate the turnaround time of the transceiver and does not exceed 16μs.

[0067] Category 2: LBT without random fallback

[0068] The duration that the channel (where the transmission is intended to be performed) is sensed as idle before the transmitting entity transmits is deterministic.

[0069] Category 3: LBT with random backoff with fixed-size contention window

[0070] The LBT process has the following as one of its components. The transmission entity draws a random number N within the contention window. The size of the contention window is specified by the minimum and maximum values ​​of N. The size of the contention window is fixed. The random number N is used in the LBT process to determine the duration of time that the channel (where the transmission is intended to be performed) is sensed as idle before the transmission entity transmits on the channel.

[0071] Category 4: LBT with random backoffs with contention windows of variable size

[0072] The LBT process has the following as one of its components. The transmission entity draws a random number N within the contention window. The size of the contention window is specified by the minimum and maximum values ​​of N. The transmission entity can change the size of the contention window when drawing the random number N. The random number N is used in the LBT process to determine the duration of the channel (where the transmission is intended to be performed) that the transmission entity is sensed as idle before transmitting on the channel.

[0073] For example, as explained in each LBT category discussed above, transmission can be performed by the UE only when LBT is successful. In addition, the maximum continuous transmission time (in case of successful LBT) can be predetermined by the COT value. Based on the concept of the LBT mechanism, RAN Working Group 2 (WG2) has agreed to assume that if a transmission is not performed on the PUSCH resources due to an LBT failure (e.g., LBT is not successful), the configured grant timer corresponding to the HARQ process of the PUSCH resources of the configured uplink grant is not (re)started. RAN WG2 also assumes that pending transport blocks (TB) that were not transmitted on the configured uplink grant resources due to LBT failure can be retransmitted in the (subsequent) configured uplink grant resources (using the same HARQ process).

[0074] If LBT Category 2 / 3 / 4 is performed, during the LBT process, if the channel is sensed as idle (e.g., the power detected by the UE intending to perform UL transmission is less than a predetermined / configured power threshold) for a predetermined / configured duration, the LBT may be considered successful. If the UE performs LBT Category 1, the LBT may be considered successful. Otherwise, the LBT is considered to have failed. Upon one / multiple LBT failures, the UE's MAC entity may receive an LBT failure indication from the UE's PHY layer.

[0075] In various embodiments of the present disclosure, the term "UL-LBT" may refer to an LBT process performed by a UE prior to an UL transmission. The term "DL-LBT" may refer to an LBT process performed by a network prior to a DL transmission. Various embodiments of the present disclosure describe mechanisms for handling "consistent" UL-LBT failures.

[0076] UL LBT failure may delay UL transmissions because it means that the UE has to (re)transmit data on subsequent UL resources. In addition, some UL transmissions may be initiated by the UE (e.g., CBRA, SR, transmission on configured uplink granted resources, etc.). Therefore, if the UE fails to perform UL transmission due to suffering a UL-LBT failure, the network is not aware of it. In order to address the given problem, 3GPP RAN WG2 has agreed to introduce a UL-LBT failure mechanism that handles (consistent) UL-LBT failures in NR-U systems. Therefore, in the event of a (consistent) UL-LBT failure, the UE can initiate an LBT recovery procedure to prevent the UE from suffering a UL-LBT failure, which may cause further delays in UL transmissions.

[0077] Counters (e.g., LBT counters), timers (e.g., LBT timers), and thresholds (e.g., maximum values ​​or MaxLBT thresholds) may be introduced into the UL-LBT failure mechanism. In addition, the LBT counter, LBT timer, and MaxLBT threshold may be configured and / or maintained per BWP, cell, cell group (Cell Group, CG), or a subset of CG. The LBT counter may be initially set to zero during configuration, and may be incremented by the UE each time a UL LBT failure occurs. For example, a UL LBT failure may occur when the MAC entity of the UE receives an LBT failure indication from the PHY layer. For example, a UL LBT failure may be caused by any (or specific) UL transmission type. That is, the LBT counter may be increased when any (or specific) type of UL transmission cannot be performed due to a UL LBT failure being detected. In one example, the LBT counter may be increased by one for a UE detecting one (or more) UL LBT failures. In addition, the time window may be configured by the network so that the LBT counter may be increased by a specific value only within the time window.

[0078] In one embodiment, the network may configure an LBT timer to the UE. In one embodiment, when any (or specific) type of UL transmission cannot be performed due to UL LBT failure, the LBT timer may be (re)started. In another embodiment, the UE may (re)start the LBT timer as long as the LBT counter increases. When the LBT timer expires, the LBT counter may be reset.

[0079] Whenever the LBT counter reaches the MaxLBT threshold, a continuous or consistent UL LBT failure is detected (on the corresponding BWP, cell, CG or CG subset, where the LBT counter, LBT timer and / or LBT threshold are maintained and / or configured). Therefore, the UE can initiate a recovery process (e.g., an LBT recovery process). In one example, when the LBT counter reaches the MaxLBT threshold, the UE can declare a radio link failure (Radio Link Failure, RLF). In one example, the UE can initiate a random access (Random Access, RA) process on the same frequency range as the frequency range where the continuous or consistent UL LBT failure is detected. In one example, the UE can initiate a RA process on a different frequency range where continuous or consistent UL LBT failure is detected (e.g., by BWP switching). In various embodiments of the present disclosure, the same frequency range may be referred to as the same BWP, sub-band, cell, CG, a subset of CG, etc.

[0080] In one example, a common LBT recovery process may be applied to both PCell and SCell. In another example, different LBT recovery processes may be applied to different cells. For example, if continuous or consistent UL LBT failures are detected on PCell, the UE may declare RLF, and if continuous or consistent UL LBT failures are detected on SCell, the UE may initiate a RA process on the same or different frequency ranges.

[0081] Continuous or consistent UL LBT failures may be detected per BWP, cell, CG, or CG subset. For example, a parameter set for a UL LBT failure mechanism (e.g., LBT counter, LBT timer, MaxLBT, etc.) may be configured and / or maintained per BWP, cell, CG, or CG subset. Thus, an LBT recovery procedure may be initiated on each of a BWP, cell, CG, or CG subset.

[0082] Retransmission handling on configured uplink granted resources

[0083] As described above, 3GPP RAN WG2 has agreed to assume that if no transmission is performed on the PUSCH resource due to LBT failure, the configuration grant timer corresponding to the HARQ process ID of the PUSCH resource of the configuration uplink grant is not (re) initiated. In addition, 3GPP RAN WG2 also assumes that the pending TB can be (re)transmitted in the (subsequent) configured uplink grant resource (with the same HARQ process ID), where the pending TB was not transmitted on the configured uplink grant resource due to LBT failure. However, based on the current MAC specification, if the configuration grant timer for the corresponding HARQ process is not running / configured, the configured uplink grant resource of the activated configured uplink grant can only be used for new transmissions (for example, the UE believes that the NDI of the HARQ process ID of the configured uplink grant resource has been switched). For example, if the HARQ process ID of the configured uplink grant resource is determined to be 1, then if the configuration grant timer with HARQ process ID 1 is not running / configured, the configured uplink grant resource is used for new transmissions. Therefore, a new mechanism is needed to allow retransmission on the configured uplink grant resources even if the configuration grant timer of the corresponding HARQ process ID is not running / configured (for example, the UE believes that the NDI of the HARQ process ID of the configured uplink grant resources has not been switched).

[0084] Figure 2 is a diagram showing a method for processing retransmissions on configured uplink granted resources according to various embodiments of the present disclosure.

[0085] As shown in Figure 200, at time T201, the UE generates TB1 for transmission on configured uplink grant resource 1 (e.g., CGPUSCH1). At time T202, the UE attempts to send TB1 on CG PUSCH1, but fails due to LBT failure or intra-UE prioritization (e.g., CG PUSCH1 is de-prioritized as a result of intra-UE prioritization). At time T203, another configured uplink grant resource (CG PUSCH2) is available. It should be noted that CG PUSCH2 is intended for new transmission of another TB. That is, the UE generates a new TB for transmission on CG PUSCH2. Note that the configured uplink grant resource may be referred to as a UL resource (e.g., PUSCH), which corresponds to / associated with the configured grant configuration in the present disclosure.

[0086] Embodiments of the present disclosure describe various methods for determining whether CG PUSCH2 may be used for transmission of TB1. For example, various methods may allow a UE to send TB1 on CG PUSCH2, which TB1 was not sent due to LBT failure or due to being de-prioritized as a result of intra-UE prioritization, while a configured grant timer corresponding to the HARQ process ID of CG PUSCH2 is not running / configured. As discussed below, the method that may be used to determine whether CG PUSCH2 may be used for transmission of TB1 may be at least one of the following: condition-based, timer-based, state variable-based, counter-based.

[0087] Conditional handling of retransmissions on configured uplink granted resources

[0088] In various embodiments of the present disclosure, even if the configuration grant timer corresponding to the HARQ process of the configuration uplink grant resource is not running / configured, a new condition may be introduced to conditionally allow retransmission on the configuration uplink grant resource (e.g., the UE considers that the NDI is not switched). Here, retransmission may be referred to as transmitting a MAC PDU / TB that has been generated / obtained.

[0089] Therefore, a TB that is not transmitted on the configured uplink grant resources due to a specific reason (e.g., LBT failure) can be (re)transmitted on the configured uplink grant resources (assuming that the configured uplink grant resources of the transmitted TB belong to the same or different configured grant configuration as the configured uplink grant resources of the non-transmitted TB).

[0090] Figure 3 300 is a diagram illustrating conditional processing of retransmissions on configured uplink grant resources (e.g., PUSCHs corresponding to configured grant configurations) according to an exemplary embodiment of the present disclosure. As shown in FIG. 300 , at time T301, the UE generates TB1 for transmission on configured uplink grant resources 1 (e.g., CG PUSCH1). At time T302, the UE attempts to transmit TB1 on CGPUSCH1, but fails due to LBT failure or intra-UE prioritization (e.g., CG PUSCH1 is de-prioritized as a result of intra-UE prioritization). At time T303, the UE may perform (re)transmission of TB1 on configured uplink grant resources 2 (e.g., CG PUSCH2) if at least one of the following characteristics is present:

[0091] • If the configuration grant timer of the HARQ process ID configuring uplink grant resource 2 (eg, CG PUSCH2) is not running / configured, i.e., CG PUSCH2 is used for new transmissions.

[0092] If the configured grant timer of the HARQ process ID configured with uplink grant resource 2 (eg, CG PUSCH2) is running, i.e., CG PUSCH2 is used for retransmission.

[0093] If uplink grant resource 2 (eg, CG PUSCH2) is configured not to overlap with other UL resources in the time domain.

[0094] If, as a result of intra-UE prioritization, uplink grant resource 2 (eg, CG PUSCH2) is configured with priority over other UL resources that it overlaps in the time domain.

[0095] If the configured uplink grant resource 1 (eg, CG PUSCH1) and the configured uplink grant resource 2 (eg, CG PUSCH2) correspond to the same HARQ process ID.

[0096] If the configured uplink grant resource 1 (e.g., CG PUSCH1) and the configured uplink grant resource 2 (e.g., CG PUSCH2) belong to the same frequency range (e.g., scheduled / configured on the same BWP, cell, CG, or subset of CGs). It should be noted that under this condition, the configured uplink grant resource 2 (e.g., CG PUSCH2) and the configured uplink grant resource 1 (e.g., CG PUSCH1) may belong to different configured grant configurations.

[0097] If there is a TB in the HARQ buffer, the HARQ buffer corresponds to the HARQ process ID configured with uplink grant resource 1 (eg, CG PUSCH1).

[0098] If the size of the configured uplink grant resource 1 (eg, CG PUSCH1) matches the size of the configured uplink grant resource 2 (eg, CG PUSCH2).

[0099] If the configured uplink grant resource 1 (eg, CG PUSCH1) and the configured uplink grant resource 2 (eg, CG PUSCH2) correspond to different HARQ process IDs, and the HARQ buffer corresponding to the configured uplink grant resource 2 (eg, CGPUSCH2) does not contain a TB.

[0100] If the configured uplink grant resource 2 (eg, CG PUSCH2) is the first (or next) configured uplink grant resource that appears after the configured uplink grant resource 1 (eg, CG PUSCH1).

[0101] If the configured uplink grant resource 2 (eg, CG PUSCH2) is the first (or next) configured uplink grant resource that occurs after the backoff time interval when the LBT corresponding to the configured uplink grant resource 1 (eg, CG PUSCH1) fails.

[0102] ·If uplink grant resource 2 (e.g., CG PUSCH2) is configured by configuration grant configuration 2, which is the next configuration received by the UE after configuration grant configuration 1, and the configuration grant configuration 1 configures uplink grant resource 1 (e.g., CG PUSCH1).

[0103] If the configured uplink grant resource 2 (e.g., CG PUSCH2) and the configured uplink grant resource 1 (e.g., CG PUSCH1) belong to the same configured grant configuration. More specifically, when an ACK for the HARQ process ID (e.g., HARQ ID=i) is received from the network and / or when the configured grant timer using the HARQ process ID (e.g., HARQ ID=i) expires, this condition may work under the assumption that the UE may clear the HARQ buffer corresponding to the HARQ process ID (e.g., HARQ ID=i).

[0104] If the size of the TB in the HARQ buffer corresponding to the HARQ process ID configuring uplink grant resource 1 (eg, CG PUSCH1) is smaller than the size of the TB in the HARQ buffer configuring uplink grant resource 2 (eg, CG PUSCH2).

[0105] If configuring uplink grant resource 1 (e.g., CG PUSCH1) and configuring uplink grant resource 2 (e.g., CG PUSCH2) belong to two configuration grant configurations, and some specific parameters for the two configuration grant configurations are the same. Here, the specific parameters may be repK, periodicity, MCS-table, repK-RV, etc.

[0106] If the configuration grant configuration to which the uplink grant resource 1 (eg, CG PUSCH1) belongs is configured with a repetition count of 1, for example, repK[3] configured in the configuration grant configuration is 1.

[0107] If the UE does not receive a dynamic grant from the network for retransmitting the configured uplink grant resource 1 (e.g., CG PUSCH1) within a specific period after configuring the uplink grant resource 1. Such a specific period may be configured by the network via specific signaling (e.g., via RRC / DCI / MAC CE configuration).

[0108] If the LBT counter (configured on the frequency range to which uplink grant resource 1 (eg, CG PUSCH1) is configured) does not reach MaxLBT (configured on the frequency range to which uplink grant resource 1 is configured). A frequency range may refer to a BWP, a cell, a CG, or a subset of a CG.

[0109] If the configuration grant configuration to which the configuration uplink grant resource 1 belongs has not been cleared / deactivated / reconfigured / suspended.

[0110] • If the transmission fails the retry state variable (corresponding to the HARQ process configured with uplink grant resource 1 (eg, CGPUSCH1)) (described below) is set to FALSE.

[0111] • If the transmission failure timer (corresponding to the HARQ process configured with uplink grant resource 1) (described below) is still running.

[0112] If the transmission_attempt_counter (corresponding to the HARQ process configured with uplink grant resource 1 (eg, CG PUSCH1)) (described below) has not reached the maximum transmission attempts (described below).

[0113] Note that CG PUSCH1 and CG PUSCH2 may belong to / associated with the same or a single configured grant configuration, or be configured by the same or a single configured grant configuration. Note that CG PUSCH1 and CG PUSCH2 may belong to different bundles of the same configured grant configuration. Note that if parameter repK is configured as a configured grant configuration, a bundle may include multiple configured uplink grant resources, and the number may be defined by repK. In addition, after a new transmission, repK–1 HARQ retransmissions (repetitions) may appear in the bundle.

[0114] In one aspect, CG PUSCH1 may belong to a configuration grant type 1 configuration (where retransmission is allowed on the corresponding configured uplink grant resources), a configuration grant type 2 configuration (where retransmission is allowed on the corresponding configured uplink grant resources), etc.

[0115] In one aspect, CG PUSCH2 may belong to configuration grant type 1 (where retransmission is allowed on the corresponding configured uplink grant resources), configuration grant type 2 (where retransmission is allowed on the corresponding configured uplink grant resources), etc.

[0116] In one example, multiple configuration grant configurations may be activated on the same BWP. Thus, if the UE fails to perform a transmission on CGPUSCH1 (e.g. due to LBT failure or due to CG PUSCH1 being de-prioritized as a result of intra-UE prioritization), the UE may perform a (re)transmission on CG PUSCH2 even if CG PUSCH1 and CG PUSCH2 belong to different configuration grant configurations, as long as they belong to the same BWP (and the same HARQ process ID). In this embodiment, it is assumed that the configuration grant timer for the HARQ process ID of CG PUSCH2 is not running / configured and that CG PUSCH2 does not overlap with other UL resources in the time domain.

[0117] In one example, if the UE fails to perform transmission of TB1 on CG PUSCH1 (for example, due to LBT failure or because CG PUSCH1 is de-prioritized as a result of prioritization within the UE), the UE can perform (re)transmission on CGPUSCH2 only if CG PUSCH1 is not configured for repetition (repK[3] is 1 in the configured grant configuration to which uplink grant resource 1 belongs). That is, if CG PUSCH1 is configured as repK>1, LBT can succeed on the repetition resources of configured uplink grant resource 1. Therefore, there is no need to rely on CG PUSCH2 for retransmission. In this implementation, it is assumed that the grant timer configured for the HARQ process ID of CG PUSCH2 is not running / configured and that CG PUSCH2 does not overlap with other UL resources in the time domain.

[0118] In one example, the UE may detect an LBT failure, which leads to the conclusion that transmission on CG PUSCH1 is not allowed. However, when the LBT failure is detected, TB1 corresponding to CG PUSCH1 may not be generated. Therefore, the UE may perform (re)transmission on another configured uplink grant resource (e.g., CG PUSCH2) only when the TB corresponding to CG PUSCH1 (e.g., TB1) has been generated, for example, when the HARQ buffer corresponding to CG PUSCH1 is not empty. Alternatively, the UE may always complete / perform the generation of a TB (e.g., TB1) even if the transmission of the TB (e.g., TB1) cannot be performed due to an LBT failure, which may be detected before or during the UE generates the TB (e.g., TB1). In another example, the UE may perform LBT after the TB corresponding to the UL transmission (e.g., TB1) is completely generated. Specifically, the example may work under the following assumption: when an ACK with a HARQ process ID of i is received from the network and / or when the configured grant timer with the HARQ process ID of i expires, the UE may clear the HARQ buffer corresponding to the HARQ process ID of i.

[0119] In one example, if the UE fails to perform transmission of a TB (e.g., TB1) on CG PUSCH1 (e.g., due to LBT failure or because CG PUSCH1 is de-prioritized as a result of prioritization within the UE), when CG PUSCH2 may be the same HARQ process ID as CG PUSCH1, the UE may attempt to perform (re)transmission of the TB (e.g., TB1 included in the HARQ buffer) on CG PUSCH2. Therefore, if a TB (e.g., TB1) has been generated (and not transmitted due to LBT failure), the UE may not perform a new transmission (e.g., a dynamic uplink grant scheduled by the gNB) using the same HARQ process ID as that of the TB until the TB (e.g., TB1) is (re)transmitted (e.g., via CG PUSCH2).

[0120] In one example, if the UE fails to perform transmission of a TB (e.g., TB1) on CG PUSCH1 (e.g., due to LBT failure or because CG PUSCH1 is de-prioritized as a result of prioritization within the UE), the UE can perform (re)transmission of a TB (e.g., TB1) on CG PUSCH2 only if CG PUSCH2 is used for new transmissions (e.g., the configured grant timer corresponding to the HARQ process ID of CG PUSCH2 is not running / configured) has the same HARQ process ID as CG PUSCH1 and both CG PUSCH1 and CG PUSCH2 are configured in the same (UL) BWP.

[0121] For example, the UE may ignore any (dynamic) scheduling of new transmissions (or retransmissions) with the same HARQ process ID as a TB until the TB is (re)transmitted (e.g., via CG PUSCH2). In another example, before the TB is (re)transmitted (e.g., via CG PUSCH2), the UE may consider the NDI of any (dynamic) scheduling of new transmissions (or retransmissions) with the same HARQ process ID as the TB and no switching will be performed regardless of the value of the NDI.

[0122] In one example, if the UE fails to perform transmission of a TB (e.g., TB1) on CG PUSCH1 (e.g., because CG PUSCH1 is de-prioritized as a result of prioritization within the UE or due to LBT failure), if CG PUSCH2 has at least one of the above characteristics, the UE may perform (re)transmission of the TB (e.g., TB1) on CG PUSCH2. In this example, CG PUSCH2 may be used for new transmissions (e.g., the configured grant timer for the HARQ process ID of CG PUSCH2 is not running / configured). Therefore, if a TB (e.g., TB1) cannot be (re)transmitted on CG PUSCH2, a new MAC PDU / TB may be generated for transmission on CG PUSCH2.

[0123] Timer-based handling of retransmissions on configured uplink granted resources

[0124] In various embodiments of the present disclosure, a timer (e.g., a transmission failure timer) may be configured by the network to the UE. The timer may be maintained per HARQ process. The transmission failure timer defines a period for retransmissions (e.g., considering that the NDI is not switched) of a TB (not transmitted due to LBT failure), the retransmission of which corresponds to a HARQ process for which a timer is allowed on a configured uplink grant resource, even if the configured uplink grant resource is determined to be used for a new transmission, according to the current MAC specification. (e.g., the configured grant timer corresponding to the HARQ process for which the uplink grant resource is configured is not running / configured).

[0125] In one example, if the transmission failure timer of HARQ process A is running, the UE may use the configured uplink grant resources for retransmissions of TBs (corresponding to LBT failures of HARQ process A that were not transmitted) (e.g., considering the untriggered NDI), the retransmissions of which correspond to HARQ process A (e.g., the TBs are stored in the HARQ buffer corresponding to HARQ process A). On the other hand, if the transmission failure timer of HARQ process A is not configured or is not running, the UE may only use the configured uplink grant resources for new transmissions. For example, if the configured grant timer with HARQ process A is not running / configured, the UE may not use the configured uplink grant resources together with HARQ process A for retransmissions of TBs that were not transmitted due to LBT failures.

[0126] In one example, if the transmission failure timer for HARQ process A is running, the UE may not use HARQ process A for any new transmissions (e.g., considering that the NDI has been switched). When the transmission failure timer for HARQ process A is running, the UE may ignore dynamic grants for new transmissions using HARQ process A. In another example, when the transmission failure timer for HARQ process A is running, the UE may consider any (dynamically) scheduled NDI for new transmissions (or retransmissions) with HARQ process A not to be switched regardless of the value of the NDI.

[0127] In some embodiments of the present disclosure, a transmission failure timer may be configured for a BWP, a cell, a CG, or a subset of CGs. In some embodiments of the present disclosure, a transmission failure timer may be configured via RRC signaling (e.g., included in a ConfiguredGrantConfig IE). In some embodiments of the present disclosure, a transmission failure timer may be configured in units of symbols / slots / milliseconds / multiples of a configured uplink grant periodicity.

[0128] Figure 4400 is a diagram illustrating timer-based processing of retransmissions on configured uplink granted resources according to an exemplary embodiment of the present disclosure. As shown in FIG400 , at time T401, the UE generates TB1 for transmission on configured granted (CG) PUSCH1. For example, at time T402, when the UE attempts but fails to transmit TB1 on CG PUSCH1 due to LBT failure or intra-UE prioritization (e.g., CG PUSCH1 is de-prioritized as a result of intra-UE prioritization), the transmission failure timer starts. At time 403, while the transmission failure timer is running, if both CG PUSCH1 and CG PUSCH2 have the same HARQ ID (e.g., HARQ ID=1), the UE may perform (re)transmission of TB1 on configured uplink granted resources (e.g., CG PUSCH2).

[0129] In various embodiments of the present disclosure, the transmission failure timer (corresponding to a specific HARQ process ID) may be (re)started when one or more of the following conditions are met:

[0130] When a configured uplink grant resource (corresponding to the HARQ process ID of the transmission failure timer) is configured and activated (and the configured grant configuration to which the configured uplink grant resource belongs can be used for retransmission), and the configured grant timer corresponds to the HARQ process of the configured uplink grant resource is not running / configured.

[0131] When a TB (HARQ process ID corresponding to the transmission failure timer) is not transmitted on UL resources due to LBT failure.

[0132] • When the TB (corresponding to the HARQ process ID of the transmission failure timer) is not transmitted on the UL resources due to intra-UE prioritization (eg, the UL resources are de-prioritized as a result of intra-UE prioritization).

[0133] When a TB (HARQ process ID corresponding to the transmission failure timer) does not transmit on UL resources due to LBT failure, and the LBT counter (configured on the same frequency range as the TB) does not reach MaxLBT (configured on the same frequency range as the TB). The frequency range may refer to a BWP, a cell, a CG, or a subset of a CG.

[0134] When the TB (HARQ process ID corresponding to the transmission failure timer) is not transmitted on UL resources due to intra-UE prioritization (e.g., UL resources are de-prioritized as a result of intra-UE prioritization), and the LBT counter (configured on the same frequency range as the TB) has not reached MaxLBT (configured on the same frequency range as the TB). The frequency range may refer to a BWP, a cell, a CG, or a subset of a CG.

[0135] • When a (new) transmission of a HARQ process is not successfully transmitted on a configured grant due to LBT failure.

[0136] • When starting or restarting a configuration grant timer, wherein the configuration grant timer may be associated with the same HARQ process as the transmission failure timer.

[0137] Specifically, the UL resources may be configured by the gNB via RRC. For example, a grant type 1 configuration (where retransmission is allowed on the corresponding configured uplink grant resources) or a grant type 2 configuration (where retransmission is allowed on the corresponding configured uplink grant resources) may be configured. In another example, the UL resources may be scheduled by the gNB via DCI.

[0138] In various embodiments of the present disclosure, the transmission failure timer (corresponding to a specific HARQ process ID) may be stopped when one or more of the following conditions are met:

[0139] When the TB that started this transmission failure timer has been (re)transmitted on the configured uplink granted resources (the same HARQ process ID corresponding to the transmission failure timer).

[0140] For example, configuring uplink grant resources may belong to configuring grant type 1 configuration (where retransmission is allowed on corresponding configured uplink grant resources), configuring grant type 2 configuration (where retransmission is allowed on corresponding configured uplink grant resources), and the like.

[0141] When the TB that started this transmission failure timer has been (re)transmitted on a UL resource, this UL resource is scheduled by the network for dynamic retransmission (same as the HARQ process ID corresponding to the transmission failure timer).

[0142] • When a retransmission of a HARQ process is successfully transmitted on a configured grant, where a transmission failure timer is associated with the HARQ process.

[0143] When the serving cell corresponding to the TB that started this transmission failure timer has been deactivated.

[0144] After a MAC reset / reconfiguration.

[0145] • The BWP (corresponding to the TB that started this transmission failure timer) is deactivated.

[0146] ·Perform BWP switching.

[0147] • BFR is detected on the serving cell (corresponding to the TB that started this transmission failure timer).

[0148] If the LBT counter (configured in the same frequency range as the TB that initiated this transmission failure timer) has reached MaxLBT (configured in the same frequency range as the TB that initiated this transmission failure timer). A frequency range may refer to a BWP, a cell, a CG, or a subset of a CG.

[0149] • If a RA procedure initiated by the UE due to consistent UL LBT failure (eg, LBT counter is equal to or greater than MaxLBT) has been initiated.

[0150] • If the RA procedure initiated by the UE has been completed due to consistent UL LBT failure (eg, LBT counter is equal to or greater than MaxLBT).

[0151] If the configuration authorization configuration corresponding to the TB that started this transfer failure timer has been deactivated / cleared.

[0152] If the HARQ buffer corresponding to the TB that started this transmission failure timer has been cleared / overwritten by another TB.

[0153] If the configuration grant corresponding to the transmission failure timer is (re)activated, deactivated and / or released. For example, when a transmission failure occurs on a configuration grant due to an LBT failure, the transmission failure timer (re)starts.

[0154] Handling retransmissions on configured uplink grant resources based on state variables

[0155] In various embodiments of the present disclosure, a new state variable (e.g., transmission failure retry) may be maintained per HARQ process. This state variable may indicate a FALSE state or a TRUE state. When transmission failure retry is set to FALSE, according to the current MAC specification (e.g., the configured grant timer corresponding to the HARQ process for which the uplink grant resources are configured is not running / configured), retransmission of a TB (not transmitted due to LBT failure) corresponding to the HARQ process for which the uplink grant resources are configured is allowed on the uplink grant resources even if the uplink grant resources are determined to be used for new transmissions.

[0156] For example, if the transmission failure retry for HARQ process A is set to FALSE, the UE may use the configured uplink grant resources with HARQ process A to retransmit the TB (which was not transmitted due to LBT failure) when the configured grant timer with HARQ process A is not running / configured. On the other hand, if the transmission failure retry for HARQ process A is set to TRUE, the UE may only use the configured uplink grant resources with HARQ process A for new transmissions if the configured grant timer with HARQ process A is not running / configured (e.g., considering that NDI has been switched).

[0157] In one example, if transmission failure retry for HARQ process A is set to FALSE, the UE may not use HARQ process A for any new transmission. When transmission failure retry for HARQ process A is set to FALSE, the UE may ignore dynamic grants for new transmissions using HARQ process A. In another example, when transmission failure retry for HARQ process A is set to FALSE, the UE may consider any (dynamically) scheduled NDI for new transmissions (or retransmissions) with HARQ process A, regardless of the value of the NDI, not toggled.

[0158] Figure 5 500 is a diagram illustrating state variable-based processing of retransmissions on configured uplink grant resources according to an exemplary embodiment of the present disclosure. As shown in Figure 500, at time T501, the UE generates TB1 for transmission on configured grant (CG) PUSCH1. For example, at time T502, the UE attempts but fails to transmit TB1 on CG PUSCH1 due to LBT failure or intra-UE prioritization (e.g., CG PUSCH1 is de-prioritized as a result of intra-UE prioritization). The transmission failure retry stable variable of HARQ ID=1 is set to FALSE. At time T503, when the transmission failure retry stable variable of HARQ ID=1 is set to FALSE, if both CG PUSCH1 and CG PUSCH2 have the same HARQ ID (e.g., HARQ ID=1), the UE can perform (re)transmission of TB1 on configured uplink grant resources (e.g., CG PUSCH2).

[0159] In various embodiments of the present disclosure, the UE may set a transmission failure retry state variable (corresponding to a specific HARQ process ID) to FALSE if one or more of the following conditions are met:

[0160] When a configured uplink grant resource (corresponding to the HARQ process ID for transmission failure retry) is configured and / or activated (and the configured grant configuration to which the configured uplink grant resource belongs can be used for retransmission), and the configured grant timer corresponding to the HARQ process of the configured uplink grant resource is not running / configured.

[0161] When a TB (HARQ process ID corresponding to the transmission failure retry state variable) is not transmitted on UL resources due to LBT failure.

[0162] • When a TB (corresponding to the HARQ process ID of the transmission failure retry state variable) is not transmitted on the UL resources due to intra-UE prioritization (eg, the UL resources are de-prioritized as a result of intra-UE prioritization).

[0163] When a TB (corresponding to the HARQ process ID of the transmission failure retry state variable) is not transmitted on UL resources due to LBT failure, and the LBT counter (configured on the same serving cell that maintains the transmission failure retry) does not reach MaxLBT (configured on the same serving cell that maintains the transmission failure retry).

[0164] When a TB (corresponding to the HARQ process ID of the transmission failure retry state variable) is not transmitted on UL resources due to intra-UE prioritization (e.g., UL resources are de-prioritized as a result of intra-UE prioritization), and the LBT counter (configured on the same serving cell that maintains the transmission failure retry) does not reach MaxLBT (configured on the same serving cell that maintains the transmission failure retry).

[0165] When the MAC is reset / reconfigured.

[0166] When the serving cell that maintains transmission failure retry is deactivated.

[0167] • When a (new) transmission of a HARQ process is not successfully transmitted on a configured grant due to LBT failure.

[0168] Specifically, the UL resources may be configured by the gNB via RRC. For example, a grant type 1 configuration (where retransmission is allowed on the corresponding configured uplink grant resources) and a grant type 2 configuration (where retransmission is allowed on the corresponding configured uplink grant resources).

[0169] Specifically, UL resources can be scheduled by gNB via DCI.

[0170] In various embodiments of the present disclosure, the UE may set a transmission failure retry state variable (corresponding to a specific HARQ process ID) to TRUE when one or more of the following conditions are met:

[0171] When (re)transmitting a TB on the configured uplink granted resources (with the same HARQ process ID as that corresponding to the retry of failed transmission).

[0172] More specifically, the configured uplink grant resources may belong to a configured grant type 1 configuration (where retransmission is allowed on the corresponding configured uplink grant resources), a configured grant type 2 configuration (where retransmission is allowed on the corresponding configured uplink grant resources), and the like.

[0173] • When the TB has been retransmitted on UL resources scheduled by the network for dynamic transmission (same HARQ process ID as corresponding to the transmission failure retry).

[0174] When the MAC is reset / reconfigured.

[0175] When the serving cell that maintains transmission failure retry is deactivated.

[0176] If the LBT counter (configured on the same serving cell that maintains the transmission failure retry) has reached MaxLBT (configured on the same serving cell that maintains the transmission failure retry).

[0177] • If a RA procedure initiated by the UE due to consistent UL LBT failure (eg, LBT counter is equal to or greater than MaxLBT) has been initiated.

[0178] • If the RA procedure initiated by the UE has been completed due to consistent UL LBT failure (eg, LBT counter is equal to or greater than MaxLBT).

[0179] If the HARQ buffer corresponding to the TB that started this transmission failure timer has been cleared / overwritten by another TB.

[0180] When the serving cell that maintains transmission failure retry is deactivated.

[0181] If the configuration grant corresponding to the transfer failure timer is (re)activated, deactivated and / or released. For example, when a transfer failure occurs on a configuration grant due to an LBT failure, TransferFailureRetry is set to FALSE.

[0182] Counter-based handling of retransmissions on configured uplink grant resources

[0183] In various embodiments of the present disclosure, a new counter (e.g., transmission_attempt_counter) may be maintained per HARQ process. The counter may be used to count the number of UL transmission attempts for a HARQ process. If the UE fails to transmit on a (configured granted) UL resource, the transmission_attempt_counter may be incremented, and the UL resource corresponds to the HARQ process ID of the transmission_attempt_counter.

[0184] The network may configure a new threshold (e.g., maximum transmission attempts). The threshold may be defined as the maximum number of (configured granted) UL transmission attempts that the UE may perform. If transmission_attempt_counter is less than the configured maximum transmission attempts, retransmissions of TBs (not transmitted due to LBT failure) are allowed to use the same HARQ process ID as transmission_attempt_counter on configured uplink grant resources, even if this configured uplink grant resource is determined to be used for new transmissions according to the current MAC specification (e.g., the configured grant timer corresponding to the HARQ process of the configured uplink grant resource is not running / configured). Conversely, if the value of transmission_attempt_counter reaches the maximum transmission attempts (e.g., transmission_attempt_counter is equal to or greater than the maximum transmission attempts), retransmissions of TBs (not transmitted due to LBT failure) are not allowed to use the configured uplink grant resources with the same HARQ process ID as transmission_attempt_counter according to the current MAC specification if the configured uplink grant resource is determined to be used for new transmissions (e.g., the configured grant timer corresponding to the HARQ process of the configured uplink grant resource is not running / configured).

[0185] For example, if the transmission_attempt_counter for HARQ process A has not reached the maximum transmission attempt, the UE may use the configured uplink grant resources with HARQ process A for the retransmission of the TB (which was not transmitted due to LBT failure). In another example, if the transmission failure retry for HARQ process A has reached the maximum transmission attempt, the UE may only use the configured uplink grant resources with HARQ process A for new transmission. In addition, the UE may use the configured uplink grant resources with HARQ process A for new transmission only when the configured grant timer for HARQ process A is not running.

[0186] In one example, if the transmission_attempt_counter for HARQ process A has not reached the maximum transmission attempt, the UE may not use HARQ process A for any new transmission. When the transmission_attempt_counter for HARQ process A has not reached the maximum transmission attempt, the UE may ignore the dynamic grant for new transmission using the HARQ process A. In another example, although the transmission_attempt_counter for HARQ process A has not reached the maximum transmission attempt, the UE may consider the NDI of any (dynamic) scheduling of new transmissions (or retransmissions) with HARQ process A, regardless of the value of the NDI, not toggled.

[0187] In some embodiments of the present disclosure, transmission_attempt_counter is configured per BWP, cell, CG, or a subset of CG.

[0188] In some embodiments of the present disclosure, transmission_attempt_counter may be configured via RRC signaling, for example, included in ConfiguredGrantConfig IE.

[0189] In some embodiments of the present disclosure, the maximum transmission attempt is configured per BWP, cell, CG, or a subset of CG.

[0190] In some embodiments of the present disclosure, the maximum transmission attempt may be configured via RRC signaling, for example, included in the ConfiguredGrantConfig IE.

[0191] Figure 6 600 is a diagram illustrating counter-based processing of retransmissions on configured uplink granted resources according to an exemplary embodiment of the present disclosure. As shown in Figure 600, at time T601, the UE generates TB1 for transmission on configured granted (CG) PUSCH1. At time T602, the transmission attempt counter increases by 1, such as when the UE attempts but fails to transmit TB1 on CG PUSCH1 due to LBT failure or because CG PUSCH1 is de-prioritized as a result of prioritization within the UE. At time T603, when the transmission attempt counter is less than the maximum transmission attempt, if both CG PUSCH1 and CG PUSCH2 have the same HARQ ID (e.g., HARQ ID=1), the UE can perform (re)transmission of TB1 on configured uplink granted resources (e.g., CG PUSCH2).

[0192] In various embodiments of the present disclosure, the transmission_attempt_counter (corresponding to a particular HARQ process ID) may be incremented by (1) if one or more of the following conditions are met:

[0193] When a configured uplink grant resource (corresponding to the HARQ process ID of transmission_attempt_counter) is configured and activated (and the configured grant configuration to which the configured uplink grant resource belongs is available for retransmission), and the configured grant timer of the HARQ process corresponding to the configured uplink grant resource is not running / configured.

[0194] When a TB (corresponding to the HARQ process ID of transmission_attempt_counter) is not transmitted on UL resources due to LBT failure.

[0195] • When a TB (corresponding to the HARQ process ID of the transmission_attempt_counter) is not transmitted on the UL resources because the UL resources are de-prioritized as a result of intra-UE priority.

[0196] When a TB (corresponding to the HARQ process ID of transmission_attempt_counter) is not transmitted on UL resources due to LBT failure, and the LBT counter (configured on the same serving cell that maintains transmission_attempt_counter) does not reach MaxLBT (configured on the same serving cell that maintains transmission_attempt_counter).

[0197] When a TB (corresponding to the HARQ process ID of the transmission_attempt_counter state variable) is not transmitted on UL resources because the TB is de-prioritized as a result of intra-UE priority, and the LBT counter (configured on the same serving cell where the transmission_attempt_counter is maintained) has not reached MaxLBT (configured on the same serving cell where the transmission_attempt_counter is maintained).

[0198] · UL resources due to LBT failure.

[0199] Specifically, the UL resources may be configured by the gNB via RRC. For example, a grant type 1 configuration (where retransmission is allowed on the corresponding configured uplink grant resources) or a grant type 2 configuration (where retransmission is allowed on the corresponding configured uplink grant resources) may be configured. Alternatively, the UL resources may be scheduled by the gNB via DCI.

[0200] Specifically, if the transmission attempt counter reaches a maximum time, the UE may clear the HARQ buffer corresponding to the transmission attempt counter.

[0201] In various embodiments of the present disclosure, the transmission_attempt_counter (corresponding to a specific HARQ process ID) may be reset if one or more of the following conditions are met:

[0202] When (re)transmitting a TB on the configured uplink granted resources (same as the HARQ process ID corresponding to transmission_attempt_counter).

[0203] More specifically, configuring uplink grant resources may belong to configuring grant type 1 configuration (where retransmission is allowed on corresponding configured uplink grant resources), configuring grant type 2 configuration (where retransmission is allowed on corresponding configured uplink grant resources), and the like.

[0204] • When a TB has been retransmitted on UL resources scheduled by the network for dynamic transmission (corresponding to the same HARQ process ID as transmission_attempt_counter).

[0205] When the MAC is reset / reconfigured.

[0206] When the serving cell maintaining the transmission_attempt_counter is deactivated.

[0207] If the LBT counter (configured on the same serving cell where the transmission_attempt_counter is maintained) has reached MaxLBT (configured on the same serving cell where the transmission_attempt_counter is maintained).

[0208] • If a RA procedure initiated by the UE due to consistent UL LBT failure (eg, LBT counter is equal to or greater than MaxLBT) has been initiated.

[0209] • If the RA procedure initiated by the UE has been completed due to consistent UL LBT failure (eg, LBT counter is equal to or greater than MaxLBT).

[0210] · The BWP (corresponding to the TB that initiated this transmission_attempt_counter) is deactivated.

[0211] ·Perform BWP switching.

[0212] • BFR is detected on the serving cell (corresponding to TB maintaining transmission_attempt_counter).

[0213] If the HARQ buffer corresponding to the transmission_attempt_counter has been cleared / overwritten by another TB.

[0214] If the configuration grant corresponding to the transmission_attempt_counter is (re)activated, deactivated and / or released. For example, when a transmission failure occurs on a configuration grant due to an LBT failure, the transmission attempt counter is (re)initiated.

[0215] Impact of LBT recovery process on configuring uplink granted resource retransmission

[0216] As described above, when one or more specific conditions are met, for example, whenever the LBT counter reaches MaxLBT (and if LBT fails on all subbands within the UE's current BWP), the UE may initiate an LBT recovery procedure. For example, the LBT recovery procedure may include, but is not limited to, at least one of the following procedures:

[0217] BWP switches to a specific BWP. For example, the UE may switch to its initial / default / indicated BWP. The network may provide such an indication to the UE via RRC signaling / MAC CE / DCI signaling.

[0218] The UE switches the active DL and / or UL BWP to the BWP indicated by firstActiveDownlinkBWP-Id and firstActiveUplinkBWP-Id, respectively. The gNB configures firstActiveDownlinkBWP-Id and firstActiveUplinkBWP-Id via DL RRC signaling.

[0219] · BWP switches to any BWP except the current BWP.

[0220] • Declare RLF (if consecutive or consistent UL LBT failures are detected on serving cells belonging to the MCG).

[0221] In one example, if the LBT counter maintained by the serving cell belonging to the MCG reaches MaxLBT, the UE may initiate an RRC connection reestablishment procedure. Specifically, this procedure may be performed if consistent UL LBT failure is detected in all BWPs configured with PRACH resources on the PCell.

[0222] If continuous or consistent UL LBT failures are detected on a serving cell belonging to an SCG, the procedure for reporting SCG failure is initiated.

[0223] In one example, if the LBT counter maintained by the serving cell belonging to the SCG reaches MaxLBT, the UE may initiate a procedure to report an SCG failure. Specifically, if continuous or consistent UL LBT failures are detected on the PSCell, the procedure may be performed on the MCG. Specifically, if continuous or consistent UL LBT failures are detected on a serving cell other than the PSCell, the procedure may be performed on the PSCell. Specifically, if consistent UL LBT failures are detected in all BWPs configured with PRACH resources on the PSCell, the procedure may be performed.

[0224] Initiate RA procedure (on PCell / PSCell).

[0225] • Transmit a failure report corresponding to the serving cell that detected consecutive or consistent UL LBT failures.

[0226] In one example, if the LBT counter maintained by the serving cell with ID=2 reaches MaxLBT (configured in the serving cell with ID=2), the UE may transmit a failure report to the network (on another serving cell) including information related to the service (e.g., indicating cell ID=2).

[0227] In one example, if the LBT counter maintained by the PSCell (in a DC scenario) reaches MaxLBT (configured in the PSCell), the UE may transmit a failure report to the network, which includes information related to the PSCell.

[0228] In one example, if the LBT counter maintained by the PSCell (in a DC scenario) reaches the MaxLBT of the UE's currently active BWP (configured in the PSCell), the UE may transmit an SCG failure report including PSCell-related information to the network only when consistent ULLBT failure is detected on all BWPs configured with PRACH resources on the PSCell.

[0229] When continuous or consistent UL LBT failures are detected (eg, the LBT counter reaches the MaxLBT of the serving cell), the serving cell is deactivated.

[0230] In one example, if the LBT counter maintained by the serving cell of ID=2 reaches MaxLBT (configured in the serving cell of ID=2), the serving cell of ID=2 is deactivated.

[0231] In various embodiments of the present disclosure, it is assumed that if a pending TB is not transmitted on a configured uplink grant resource (due to LBT failure), it can be (re)transmitted in a (subsequent) configured uplink grant resource (with the same HARQ process ID). However, before (re)transmitting the TB in another configured uplink grant resource (with the same HARQ process), the conditions for initiating the LBT recovery procedure may also be met (e.g., the LBT counter reaches the configured MaxLBT). If the UE behavior is to not allow (re)transmission in a (subsequent) configured uplink grant resource (with the same HARQ process) when initiating the LBT recovery procedure, at least one of the candidate UE behaviors listed below may be performed:

[0232] If certain conditions are met to initiate the LBT recovery procedure, the UE clears all HARQ buffers (configured for the configured grant configuration).

[0233] Specifically, the specific condition may be that the LBT counter is equal to or greater than the configured MaxLBT. Specifically, the UE may clear all HARQ buffers (configured for configuring the grant configuration) corresponding to the serving cell where the LBT failure problem is detected (e.g., the LBT counter maintained for the serving cell reaches MaxLBT).

[0234] · The UE clears all HARQ buffers (configured as configured grant configuration) upon BWP switching (if BWP switching is performed as part of LBT recovery procedure).

[0235] Specifically, the UE may clear all HARQ buffers (configured for configuring the grant configuration) corresponding to the serving cell in which the LBT failure problem is detected (eg, the LBT counter maintained for the serving cell reaches MaxLBT).

[0236] When the RA procedure is initiated (if the RA procedure is initiated as part of the LBT recovery procedure), the UE clears all HARQ buffers (configured as the grant configuration).

[0237] Specifically, the UE may clear all HARQ buffers (configured for configuring the grant configuration) corresponding to the serving cell in which the LBT failure problem is detected (eg, the LBT counter maintained for the serving cell reaches MaxLBT).

[0238] • Upon completion of the RA procedure (if the RA procedure was initiated as part of the LBT recovery procedure), the UE clears all HARQ buffers (configured as configured for the grant configuration).

[0239] Specifically, the UE may clear all HARQ buffers (configured for configuring the grant configuration) corresponding to the serving cell in which the LBT failure problem is detected (eg, the LBT counter maintained for the serving cell reaches MaxLBT).

[0240] If certain conditions for initiating the LBT recovery procedure are met, the UE clears a specific HARQ buffer.

[0241] Specifically, the specific condition may be that the LBT counter is equal to or greater than the configured MaxLBT. In one embodiment, if the LBT counter configured for the serving cell is equal to or greater than the configured MaxLBT, the UE may clear the specific HARQ buffer corresponding to the serving cell.

[0242] Specifically, the UE may clear a specific HARQ buffer corresponding to a serving cell where an LBT failure problem is detected, for example, the LBT counter maintained for the serving cell reaches MaxLBT.

[0243] • The UE clears the specific HARQ buffer upon BWP switching (if BWP switching is performed as part of the LBT recovery procedure).

[0244] Specifically, the UE may clear a specific HARQ buffer corresponding to a serving cell in which an LBT failure problem is detected (eg, an LBT counter maintained for the serving cell reaches MaxLBT).

[0245] The UE clears the specific HARQ buffer when the RA procedure is initiated (if the RA procedure is initiated as part of the LBT recovery procedure).

[0246] Specifically, the UE may clear a specific HARQ buffer corresponding to a serving cell where an LBT failure problem is detected, for example, the LBT counter maintained for the serving cell reaches MaxLBT.

[0247] • The UE clears the specific HARQ buffer upon completion of the RA procedure (if the RA procedure was initiated as part of the LBT recovery procedure).

[0248] Specifically, the UE may clear a specific HARQ buffer corresponding to a serving cell where an LBT failure problem is detected, for example, the LBT counter maintained for the serving cell reaches MaxLBT.

[0249] If the specific conditions of the LBT recovery procedure are met, the UE considers that all timeAlignmentTimers have expired.

[0250] Specifically, the specific condition may be that the LBT counter is equal to or greater than the configured MaxLBT.

[0251] • The UE takes into account all timeAlignmentTimers that expire at the time of BWP switching (if BWP switching is performed as part of the LBT recovery procedure).

[0252] ·The UE considers all timeAlignmentTimers as expired when the RA procedure is initiated (if the RA procedure is initiated as part of the LBT recovery procedure).

[0253] The UE considers all timeAlignmentTimers expired upon completion of the RA procedure (if the RA procedure was initiated as part of the LBT recovery procedure).

[0254] If certain conditions for initiating the LBT recovery procedure are met, the UE considers a certain timeAlignmentTimer as expired.

[0255] Specifically, the specific condition may be that the LBT counter is equal to or greater than the configured MaxLBT.

[0256] The UE considers that a specific timeAlignmentTimer expires at the time of BWP switching (if BWP switching is performed as part of the LBT recovery procedure).

[0257] The UE considers that the specific timeAlignmentTimer expires when the RA procedure is initiated (if the RA procedure is initiated as part of the LBT recovery procedure).

[0258] The UE considers the specific timeAlignmentTimer to be expired when the RA procedure is completed (if the RA procedure was initiated as part of the LBT recovery procedure).

[0259] In some embodiments of the present disclosure, the specific HARQ buffer may be any HARQ buffer having a pending TB.

[0260] In some embodiments of the present disclosure, a specific HARQ buffer may be a HARQ buffer having a pending TB due to unsuccessful transmission on UL resources. Specifically, the transmission may be unsuccessful due to detection of an LBT failure, intra-UE prioritization (e.g., UL resources are de-prioritized as a result of intra-UE prioritization), etc. Specifically, the UL resources may be configured via RRC signaling (e.g., configuring grant type 1) (where retransmission is allowed on corresponding configured uplink grant resources), configuring grant type 2 (where retransmission is allowed on corresponding configured uplink grant resources), etc.) or scheduled via DCI signaling (e.g., dynamic grant).

[0261] In case continuous or consistent UL LBT failure is detected on the SCell (for example, LBT-related parameters and counters such as LBT timer, MaxLBT, LBT counter, etc. are maintained / configured on the SCell), the specific timeAlignmentTimer may be referred to as the timeAlignmentTimer associated with the STAG to which the SCell belongs.

[0262] In case continuous or consistent UL LBT failures are detected on the SpCell (e.g., LBT-related parameters and counters such as LBT timer, MaxLBT, LBT counter, etc. are maintained / configured on the SpCell), the specific timeAlignmentTimer may be referred to as the timeAlignmentTimer associated with the PTAG.

[0263] In one example, when the LBT counter reaches the configured MaxLBT (LBT counter is equal to or greater than MaxLBT), the UE may perform the following actions in order:

[0264] • Clear the HARQ buffer using pending TBs due to unsuccessful transmission on the configured uplink grant resources.

[0265] Initiate the LBT recovery process, which involves initiating the RA process at the time of BWP switching.

[0266] In various embodiments of the present disclosure, when the LBT counter reaches the MaxLBT configured for the SCell (the LBT counter is equal to or greater than MaxLBT) (assuming that LBT-related parameters and counters, such as LBT timer, MaxLBT, LBT counter, etc., are maintained / configured on the SCell), the UE may perform the following actions in sequence:

[0267] The timeAlignmentTimer associated with the STAG to which this SCell belongs is considered expired.

[0268] In this sense, all HARQ buffers of the serving cells belonging to the STAG may be cleared.

[0269] Initiate the LBT recovery process, which involves initiating the RA process at the time of BWP switching.

[0270] Report UL LBT failure

[0271] In one embodiment of the present disclosure, if the conditions for initiating the LBT recovery process are met (e.g., continuous or consistent UL LBT failures), and the LBT recovery process (at least) includes an RLF declaration (e.g., consistent UL LBT failures are detected on the PCell), the UE may initiate an RRC connection reestablishment process and transmit an RRCReestablishmentRequest message (in the SpCell and / or after BWP switching) to report the UL LBT problem to the network.

[0272] In one embodiment, if consistent UL LBT failure is detected on all BWPs configured with PRACH resources on the PCell, the LBT recovery procedure may include (at least) a RLF declaration.

[0273] In another embodiment of the present disclosure, a new entry may be added to the ReestablishmentCause IE in the RRCReestablishmentRequest message to explicitly indicate the presence of a UL LBT problem. Specifically, if a UL LBT problem is detected on a serving cell belonging to an SCG, the ReestablishmentCause IE may explicitly indicate the presence of an SCG-UL LBT problem (e.g., the configured LBT counter on the serving cell reaches the configured MaxLBT). This may be achieved by introducing a new entry in the ReestablishmentCause IE. For example, if a UL LBT problem is detected on a serving cell belonging to an MCG, the ReestablishmentCause IE may explicitly indicate the presence of an MCG UL LBT problem (e.g., the configured LBT counter on the serving cell reaches the configured MaxLBT). This may be achieved by introducing a new entry in the ReestablishmentCause IE, which may be represented in Table 1.

[0274] Table 1 - Introduction of new entry for ReestablishmentCause IE in RRCReestablishmentRequest message (UL-LBT-Problem-MCG)

[0275]

[0276] In one embodiment of the present disclosure, if the conditions for initiating the LBT recovery process are met (e.g., continuous or consistent UL LBT failures), and the LBT recovery process (at least) includes an SCG failure report (e.g., a process for reporting SCG failure), the UE may transmit an SCGFailureInformation message (via a cell belonging to the MCG or via the PSCell) to the network to report the UL LBT problem in the SCG (in the DC). In another embodiment of the present disclosure, a new entry may be added to the failureType IE in the message to explicitly indicate that there is a UL LBT problem in the SCG. An example may be found in Table 2.

[0277] In one embodiment, if consistent UL LBT failure is detected on all BWPs configured with PRACH resources on the PSCell, the LBT recovery process may (at least) include an SCG failure report (e.g., a process for reporting an SCG failure).

[0278] Table 2 - New entry introduced in failureType IE in SCGFailureInformation message (UL-LBT-Problem-SCG)

[0279]

[0280] In one embodiment of the present disclosure, the master gNB / master eNB may transmit a CG-ConfigInfo message to the secondary gNB / secondary eNB to request the establishment / modification / or release of the SCG. In another embodiment of the present disclosure, a new entry may be added to the failureType IE in the message to explicitly indicate that there is a UL LBT problem in the SCG. An example may be found in Table 3.

[0281] Table 3 - Introduction of new entries to the failureType IE in the CG-ConfigInfo message (UL-LBT-Problem-SCG)

[0282]

[0283] In one embodiment of the present disclosure, if the conditions for initiating the LBT recovery process are met (e.g., continuous or consistent UL LBT failures), and the process (at least) includes a RA process, the UE may transmit a dedicated preamble. In addition, the dedicated preamble may be transmitted on a dedicated PRACH resource. For example, the dedicated preamble and the dedicated PRACH resource may be configured by the network via RRC signaling / DCI signaling.

[0284] In one example, if the conditions for initiating the LBT recovery procedure are met (e.g., continuous or consistent UL LBT failures), and the procedure (at least) includes BWP switching, the UE may trigger a MAC CE generation / report / transmission / confirmation. Subsequently, if the MAC CE generation / report / transmission / confirmation has been triggered, the UE may transmit the MAC CE to the network in the scheduled / configured UL resources (e.g., PUSCH resources). The purpose of the MAC CE may be to inform the network that the LBT recovery procedure has been initiated due to one or more specific conditions (e.g., continuous or consistent UL LBT failures).

[0285] Specifically, the MAC CE may include (but not limited to) one or more of the following information:

[0286] • The BWP identification (eg, BWP ID) that detected consecutive or consistent UL LBT failures (or other conditions that led to initiation of the LBT recovery process).

[0287] • Identity (e.g., BWP ID) of the serving cell where consecutive or consistent UL LBT failures were detected UL LBT failures (or other conditions leading to initiation of the LBT recovery procedure).

[0288] Identification of the CG (such as MCG or SCG) that detected continuous or consistent UL LBT failures (or other conditions that led to the initiation of the LBT recovery process).

[0289] The BWP identifier (such as BWP ID) that initiates the LBT recovery process (such as the RA process).

[0290] The identity of the serving cell (eg, BWP ID) that initiates the LBT recovery procedure (eg, RA procedure).

[0291] • Identity of the BWP (e.g. BWP ID) to which the UE switches (as part of the LBT resumption procedure).

[0292] • The identity of the serving cell (e.g., serving cell ID) that the UE deactivated (as part of the LBT recovery procedure).

[0293] Figure 7 FIG. 7 is a flowchart 700 showing a method for LBT recovery and reporting process performed by a UE according to an exemplary embodiment of the present disclosure. Figure 7As shown, in action 702, the UE may detect a consistent UL LBT failure on a serving cell (e.g., cell 1). For example, the LBT counter maintained for the serving cell reaches the MaxLBT threshold. In action 704, the UE may trigger a consistent UL LBT failure for a BWP (BWP1) on the serving cell (e.g., cell 1). In action 706, the UE may determine whether the serving cell is a SpCell or a SCell. In action 708, if the serving cell is a SpCell, the UE may determine whether a consistent UL LBT failure is triggered in all UL BWPs with PRACH on the serving cell.

[0294] In action 710, if a consistent UL LBT failure is triggered in all UL BWPs with PRACH on the serving cell, the UE may indicate a consistent UL LBT failure to the RRC layer. For example, the RRC layer may initiate a procedure to report a secondary cell group (SCG) failure information (on a primary cell group (MCG)) for a primary secondary cell (PSCell) or a radio link failure (RLF) for a primary cell (PCell). In action 712, if a consistent UL LBT failure is not triggered in all UL BWPs with PRACH on the serving cell, the UE may switch to a new BWP on the serving cell (e.g., cell 1) with PRACH resources and initiate a random access procedure, and report the LBT failure in a MAC CE in the new BWP during the RA procedure. Figure 7 As shown, flowchart 700 proceeds from act 712 to act 702 .

[0295] In action 714, if the serving cell is an SCell, the UE may determine whether UL-SCH resources are available. In action 716, if UL-SCH resources are not available, the UE may report LBT failure using a scheduling request (SR). In action 718, if UL-SCH resources are available, the UE may report LBT failure using a MAC CE that uses available UL-SCH resources. Figure 7 As shown, flowchart 700 proceeds from act 718 to act 702 .

[0296] Figure 8is a diagram showing UE behavior when an LBT recovery procedure is initiated according to an exemplary embodiment of the present disclosure. As shown in Figure 800, at time T801, the UE generates TB1 for transmission on configured grant (CG) PUSCH1. At time T802, the UE attempts to transmit TB1 on CG PUSCH1, but fails due to LBT failure or intra-UE prioritization (for example, CG PUSCH1 is de-prioritized as a result of intra-UE prioritization). At time T803, the UE initiates an LBT recovery procedure on the cell that schedules the CG PUSCH. In this embodiment, it is assumed that (re)transmission in (subsequent) configured uplink grant resources (with the same HARQ process) is not allowed at the initiation of the LBT recovery procedure. The UE may clear all HARQ buffers and consider the expiration of the time alignment timer.

[0297] Fig. 9 is a block diagram of a node for wireless communication according to various aspects of the present disclosure. Fig. 9 As shown, the node 900 may include a transceiver 920, a processor 928, a memory 934, one or more presentation components 938, and at least one antenna 936. The node 900 may also include a radio frequency (RF) band module, a BS communication module, a network communication module, a system communication management module, an input / output (I / O) port, an I / O component, and a power supply ( Fig. 9 not shown).

[0298] Each component can communicate with each other directly or indirectly via one or more buses 940. Node 900 can be an execution Fig. 9 Various functions of a UE or BS are disclosed.

[0299] The transceiver 920 may include a transmitter 922 (e.g., a transmission / transmission circuit) and a receiver 924 (e.g., a reception / reception circuit), and may be configured to send and / or receive time and / or frequency resource partitioning information. The transceiver 920 may be configured to send in different types of subframes and time slots, including but not limited to available, unavailable, and flexibly usable subframe and time slot formats. The transceiver 920 may be configured to receive data and control channels.

[0300] Node 900 may include a variety of computer-readable media. Computer-readable media may be any media that can be accessed by node 900 and includes both volatile and nonvolatile media and removable and non-removable media.

[0301] Computer readable media may include computer storage media and communication media. Computer storage media may include volatile and nonvolatile, and removable and non-removable media implemented in accordance with any method or technology for storing information such as computer readable media.

[0302] Computer storage media may include RAM, ROM, EPROM, EEPROM, flash memory or other memory technology, CD-ROM, Digital Versatile Disk (DVD) or other optical disk storage devices, magnetic cassettes, magnetic tapes, magnetic disk storage devices or other magnetic storage devices, etc. Computer storage media does not include propagated data signals. Communication media may generally be embodied as computer-readable instructions, data structures, program modules or other data in a modulated data signal (such as a carrier wave or other transport mechanism), and include any information delivery media.

[0303] The term "modulated data signal" may refer to a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. Communication media may include wired media (such as a wired network or direct-wired connection) and wireless media (such as acoustic, RF, infrared and other wireless media). Any combination of the above media should be included within the scope of computer-readable media.

[0304] The memory 934 may include computer storage media in the form of volatile and / or non-volatile memory. The memory 934 may be removable, non-removable, or a combination thereof. For example, the memory may include solid-state memory, a hard drive, an optical drive, etc. Fig. 9 As shown, the memory 934 may store computer-readable, computer-executable instructions 932 (e.g., software code) that are configured to cause the processor 928 to perform various disclosed functions when executed. Alternatively, the instructions 932 may not be directly executed by the processor 928, but may be configured to cause the node 900 (e.g., when compiled and executed) to perform various disclosed functions.

[0305] The processor 928 (e.g., having a processing circuit) may include an intelligent hardware device, a central processing unit (CPU), a microcontroller, an ASIC, etc. The processor 928 may include a memory. The processor 928 may process data 930 and instructions 932 received from the memory 934, as well as information received through the transceiver 920, the baseband communication module, and / or the network communication module. The processor 928 may also process information to be sent to the transceiver 920 for transmission via the antenna 936 and / or information to be sent to the network communication module for transmission to the core network.

[0306] One or more presentation components 938 can present data to a person or other device. Examples of presentation components 938 can include a display device, a speaker, a printing component, a vibration component, etc.

[0307] In various embodiments of the present disclosure, the CC may be a PCell, a PSCell and / or a SCell.

[0308] In various embodiments of the present disclosure, SpCell may include PCell and PSCell.

[0309] In various embodiments of the present disclosure, the UL resources may be RACH resources, PUCCH resources and / or PUSCH resources. The UL resources may be scheduled via dynamic grant (e.g., via PDCCH) and / or configured via RRC (e.g., type 1 / type 2 configured UL grant or pre-configured in RRC configuration). When a beam failure (of an SCell) is detected, the UE may trigger a BFR process (for the SCell).

[0310] In various embodiments of the present disclosure, the MAC entity may be referred to as a UE.

[0311] In various embodiments of the present disclosure, if two or more UL resources (scheduled / configured in the same serving cell) overlap in the time domain, the UE may require intra-UE prioritization. As a result of the intra-UE prioritization, the UE may select one of the overlapping UL resources for transmission. The selected UL resource may be referred to as a prioritized UL resource, and the MAC PDU / TB to be transmitted on the UL resource may be referred to as a prioritized MAC PDU / TB. Conversely, the unselected UL resource may be referred to as a non-prioritized UL resource, and the MAC PDU / TB to be transmitted on the non-prioritized UL resource may be referred to as a non-prioritized MAC PDU / TB.

[0312] In various embodiments of the present disclosure, overlapping of resources may mean partial overlapping and / or complete overlapping.

[0313] In various implementations of the present disclosure, the configuration authorization configuration may be (but is not limited to) configuration authorization type 1 or configuration authorization type 2.

[0314] In various embodiments of the present disclosure, there are two transmission types without dynamic grants: configured grant type 1, in which the uplink grant is provided by RRC and stored as a configured uplink grant; and configured grant type 2, in which the uplink grant is provided by PDCCH and is stored or cleared as a configured uplink grant based on L1 signaling indicating activation or deactivation of the configured uplink grant.

[0315] According to the present disclosure, it is apparent that various techniques may be utilized to implement the disclosed concepts without departing from the scope of these concepts. In addition, although these concepts have been disclosed with specific reference to particular embodiments, those of ordinary skill in the art will recognize that changes may be made in form and detail without departing from the scope of these concepts. Thus, the embodiments of the present disclosure will be considered illustrative and not restrictive in all respects. It should also be understood that the present disclosure is not limited to specific disclosed methods, and that many rearrangements, modifications, and substitutions of these embodiments are possible without departing from the scope of the present disclosure.

Claims

1. A user equipment UE, the UE comprising: one or more non-transitory computer-readable media containing computer-executable instructions; as well as at least one processor coupled to the one or more non-transitory computer-readable media, the at least one processor configured to execute the computer-executable instructions to: determining that transmission of a media access control MAC protocol data unit (PDU) using a first physical uplink shared channel (PUSCH) resource was not successfully performed, the first PUSCH resource being associated with a first configuration grant (CG) configuration, the first PUSCH resource being associated with a first hybrid automatic repeat request (HARQ) process, and the MAC PDU being acquired for the first HARQ process; receiving a second CG configuration; Determining that a second PUSCH resource associated with the second CG configuration can be used for another transmission, the second PUSCH resource being associated with a second HARQ process; If multiple first conditions are met, determining that the second PUSCH resource can be used to transmit the MAC PDU; as well as When it is determined that the second PUSCH resource can be used to transmit the MAC PDU, the MAC PDU is transmitted on the second PUSCH resource, and the multiple first conditions include: the second PUSCH resource available for the other transmission is used for the new transmission if at least one second condition is satisfied, the at least one second condition comprising that a configured grant timer for the second HARQ process is not running; and The second PUSCH resources and the first PUSCH resources are scheduled on the same bandwidth part BWP.

2. The UE according to claim 1, characterized in that The plurality of first conditions further include at least one of the following conditions: The first HARQ process and the second HARQ process have the same HARQ process identifier ID; The second PUSCH resource has the same size as the first PUSCH resource; The second CG configuration is the same as the first CG configuration; and The second PUSCH resource is a prioritized PUSCH resource.

3. The UE according to claim 1, characterized in that The at least one processor is further configured to execute the computer executable instructions to: If at least one of the plurality of first conditions is not satisfied, determining that the second PUSCH resource is not available for transmitting the MAC PDU; as well as When it is determined that the second PUSCH resource is not available for transmitting the MAC PDU, a new MAC PDU is generated and the new MAC PDU is transmitted on the second PUSCH resource.

4. The UE according to claim 1, characterized in that The at least one second condition further comprises: Repetition is not configured for the second CG configuration.

5. The UE according to claim 1, characterized in that Since the first PUSCH resource associated with the first CG configuration is de-prioritized, the transmission of the MAC PDU using the first PUSCH resource associated with the first CG configuration is not successfully performed.

6. The UE according to claim 1, characterized in that: When the transmission of the MAC PDU using the first PUSCH resources associated with the first CG configuration is not successfully performed, the MAC PDU is retained in a HARQ buffer associated with the first HARQ process.

7. The UE according to claim 1, characterized in that Due to UL listen-before-talk (LBT) failure, the transmission of the MAC PDU using the first PUSCH resource associated with the first CG configuration was not successfully performed.

8. The UE according to claim 7, characterized in that: The at least one processor is further configured to execute the computer executable instructions to: Increasing a LBT counter based on the UL LBT failure; and When the LBT counter reaches a threshold configured on the BWP, the first PUSCH resource is scheduled on the BWP, and the BWP belongs to a primary secondary cell PSCell, a secondary cell group SCG failure report is transmitted.

9. The UE according to claim 8, characterized in that The SCG failure report is transmitted when consistent UL LBT failure is detected on all BWPs configured with physical random access channel PRACH resources on the PSCell.

10. The UE of claim 8, characterized in that The SCG failure report includes a failure type information element IE, and the failure type IE indicates the failure type as SCG-LBT failure.

11. A method performed by a user equipment UE, the method comprising: determining that transmission of a media access control MAC protocol data unit (PDU) using a first physical uplink shared channel (PUSCH) resource was not successfully performed, the first PUSCH resource being associated with a first configuration grant (CG) configuration, the first PUSCH resource being associated with a first hybrid automatic repeat request (HARQ) process, and the MAC PDU being acquired for the first HARQ process; receiving a second CG configuration; Determining that a second PUSCH resource associated with the second CG configuration can be used for another transmission, the second PUSCH resource being associated with a second HARQ process; If multiple first conditions are met, determining that the second PUSCH resource can be used to transmit the MAC PDU; as well as When it is determined that the second PUSCH resource can be used to transmit the MAC PDU, the MAC PDU is transmitted on the second PUSCH resource, and the multiple first conditions include: the second PUSCH resource available for the other transmission is used for the new transmission if at least one second condition is satisfied, the at least one second condition comprising that a configured grant timer for the second HARQ process is not running; and The second PUSCH resources and the first PUSCH resources are scheduled on the same bandwidth part BWP.

12. The method according to claim 11, characterized in that The plurality of first conditions further include at least one of the following conditions: The first HARQ process and the second HARQ process have the same HARQ process identifier ID; The second PUSCH resource has the same size as the first PUSCH resource; The second CG configuration is the same as the first CG configuration; and The second PUSCH resource is a prioritized PUSCH resource.

13. The method according to claim 11, characterized in that The method further comprises: If at least one of the plurality of first conditions is not satisfied, determining that the second PUSCH resource is not available for transmitting the MAC PDU; and When it is determined that the second PUSCH resource is not available for transmitting the MAC PDU, a new MAC PDU is generated and the new MAC PDU is transmitted on the second PUSCH resource.

14. The method according to claim 11, characterized in that The at least one second condition further comprises: Repetition is not configured for the second CG configuration.

15. The method according to claim 11, characterized in that Since the first PUSCH resource associated with the first CG configuration is de-prioritized, the transmission of the MAC PDU using the first PUSCH resource associated with the first CG configuration is not successfully performed.

16. The method according to claim 11, characterized in that When the transmission of the MAC PDU using the first PUSCH resources associated with the first CG configuration is not successfully performed, the MAC PDU is retained in a HARQ buffer associated with the first HARQ process.

17. The method according to claim 11, characterized in that Due to UL listen-before-talk (LBT) failure, the transmission of the MAC PDU using the first PUSCH resource associated with the first CG configuration was not successfully performed.

18. The method according to claim 17, characterized in that The method further comprises: Increasing a LBT counter based on the UL LBT failure; and When the LBT counter reaches a threshold configured on the BWP, the first PUSCH resource is scheduled on the BWP, and the BWP belongs to a primary secondary cell PSCell, a secondary cell group SCG failure report is transmitted.

19. The method according to claim 18, characterized in that The SCG failure report is transmitted when consistent UL LBT failure is detected on all BWPs configured with physical random access channel PRACH resources on the PSCell.

20. The method according to claim 18, characterized in that The SCG failure report includes a failure type information element IE, and the failure type IE indicates the failure type as SCG-LBT failure.

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