Uplink listen-before-talk failure recovery

Abstract

To provide methods, systems, and devices for wireless communications.SOLUTION: User equipment (UE) 115-a may identify a BWP to be switched after identifying consistent uplink listen-before-talk (LBT) failures on a first band width part (BWP) based on parameters indicated by a base station 105-a. For example, the base station may transmit a switching parameter to the UE. The UE then uses the switching parameter to switch to a second BWP based on identifying the consistent uplink LBT failures on the first BWP. Subsequently, after selecting the second BWP, the UE may attempt to use the second BWP for uplink transmissions (e.g., after performing a random access procedure). The UE may indicate the consistent uplink LBT failures to a base station associated with the failed BWP based on a type of cell that is using that failed BWP.SELECTED DRAWING: Figure 2

Description

Priority claims

[0001] cross reference

[0001] This patent application claims the benefit of U.S. Provisional Patent Application No. 62 / 932,321, entitled "Uplink Listen-Before-Talk Failure Recovery," filed November 7, 2019, by Ozturk et al., and U.S. Patent Application No. 17 / 090,641, entitled "Uplink Listen-Before-Talk Failure Recovery," filed November 5, 2020, by Ozturk et al., each of which is assigned to the assignee of the present application. [Technical Field]

[0002] The following relates generally to wireless communications, and more particularly to uplink listen-before-talk (LBT) failure recovery. [Background technology]

[0003] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, and broadcasts. These systems may be capable of supporting communication with multiple users by sharing available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include fourth-generation (4G) systems, such as Long Term Evolution (LTE), LTE-Advanced (LTE-A), or LTE-A Pro systems, and fifth-generation (5G) systems, sometimes referred to as New Radio (NR) systems. These systems may employ technologies such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), or discrete Fourier transform spread orthogonal frequency division multiple access (DFT-S-OFDM). A wireless multiple-access communication system may include one or more base stations or one or more network access nodes, each simultaneously supporting communication for multiple communication devices, sometimes known as user equipment (UE).

[0004] In some cases, a UE and a base station may communicate over resources in an unlicensed band (e.g., an NR-unlicensed (NR-U) frequency band). For example, resources in an unlicensed band may be shared among multiple UEs (and, e.g., multiple base stations), and thus, a UE may contend for one or more of these shared resources to communicate with a base station (e.g., implementing a contention-based procedure such as a contention-based random access procedure). Thus, a UE may check whether a channel in an unlicensed band (e.g., a set of frequency resources) is clear before attempting to communicate with a base station. In some cases, this check for channel clear may include a listen-before-talk (LBT) procedure, in which the UE listens to the channel to determine whether any ongoing transmissions have occurred prior to transmitting an uplink message to the base station (e.g., whether the channel is occupied or unoccupied prior to transmitting). Summary of the Invention

[0005] The described techniques relate to improved methods, systems, devices, and apparatuses that support uplink listen-before-talk (LBT) failure recovery. Generally, the described techniques provide for a user equipment (UE) receiving from a base station switching parameters indicating how the UE should react when a consistent LBT failure is identified for a first bandwidth portion (BWP). For example, the UE may use information conveyed in the switching parameters to switch to a second BWP based on identifying a consistent LBT failure on the first BWP. In some cases, the switching parameters may indicate one or more of the following: the number of BWP switches for the UE (e.g., a maximum number of switches the UE can perform, a minimum number of switches, a fixed number of switches, etc.), whether a BWP can be switched after the failure of another BWP, a priority order in which BWPs will be switched, subband constraints for switching BWPs, whether the same BWP can be switched multiple times, a maximum time between switches to the same BWP, or a combination thereof.

[0006] Based on the information indicated in the switching parameters by the base station, the UE may select or identify a second BWP and attempt to communicate with the base station using the second BWP. For example, the UE may perform a random access procedure (e.g., a random access channel (RACH) procedure) with the base station on the second BWP to establish a connection with the base station for subsequent communication. However, if the random access procedure fails or the UE experiences another consistent LBT failure on the second BWP, the UE may declare a radio link failure (RLF), switch to a third BWP, abort the random access procedure, or a combination thereof. Additionally or alternatively, if the UE identifies a consistent LBT failure on the first BWP or the second BWP or both, the UE may report an indication of the LBT failure (e.g., via a medium access control (MAC) control element (CE), a dedicated cause value message, a recovery procedure message, etc.) based on the type of cell in which the LBT failure occurs (e.g., primary cell (PCell), secondary cell (SCell), primary SCell (PSCell), etc.).

[0007] A method of wireless communication in a UE is described. The method may include receiving, from a base station, a BWP switch configuration message including switching parameters, performing a set of LBT procedures for a first BWP, and switching to a second BWP for uplink communication with the base station based on the switching parameters and a number of failures associated with the set of LBT procedures for the first BWP.

[0008] An apparatus for wireless communication in a UE is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to receive a BWP switch configuration message from a base station, the BWP switch configuration message including switching parameters, implement a set of LBT procedures for a first BWP, and switch to a second BWP for uplink communication with the base station based on the switching parameters and a number of failures associated with the set of LBT procedures for the first BWP.

[0009] Another apparatus for wireless communication in a UE is described, which may include means for receiving a BWP switch configuration message from a base station, the BWP switch configuration message including a switch parameter, means for implementing a set of LBT procedures for a first BWP, and means for switching to a second BWP for uplink communication with the base station based on the switch parameter and a number of failures associated with the set of LBT procedures for the first BWP.

[0010] A non-transitory computer-readable medium storing code for wireless communication in a UE is described, which may include instructions executable by a processor to receive, from a base station, a BWP switch configuration message including switching parameters, implement a set of LBT procedures for a first BWP, and switch to a second BWP for uplink communication with the base station based on the switching parameters and a number of failures associated with the set of LBT procedures for the first BWP.

[0011]

[0011] Some examples of the methods, apparatus, and non-transitory computer-readable media described in this specification may further include operations, features, means, or instructions for determining the number of BWP switches based on switching parameters, where switching to a second BWP is based on the number of BWP switches.

[0012]

[0012] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the switching parameters may include an upper threshold number of BWP switching, a lower threshold number of BWP switching, a fixed number of BWP switching, or a combination thereof.

[0013]

[0013] Some examples of the methods, apparatus, and non-transitory computer-readable media described in this specification may further include operations, features, means, or instructions for selecting a second BWP based on switching parameters.

[0014]

[0014] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the switching parameters may include an indication of a priority order of the BWPs, wherein selecting the second BWP is based on the priority order of the BWPs.

[0015]

[0015] In some examples of the methods, apparatus, and non-transitory computer-readable media described in this specification, the switching parameters may include an indication of a subband constraint for the second BWP, where selecting the second BWP is based on the subband constraint.

[0016]

[0016] In some examples of the methods, apparatus, and non-transitory computer-readable media described in this specification, the second BWP may be entirely in a second subband different from the first subband of the first BWP, a subset of the second BWP may be in a second subband different from the first subband of the first BWP, or a combination thereof.

[0017]

[0017] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the switching parameters may include an indication that switching to the same BWP multiple times is permitted, where selecting a second BWP is based on the indication.

[0018]

[0018] Some examples of the methods, apparatus, and non-transitory computer-readable media described in this specification may further include operations, features, means, or instructions for determining a time threshold for switching to the same BWP, where selecting a second BWP is based on the time between successive switches to the second BWP satisfying the time threshold.

[0019]

[0019] Some examples of the methods, apparatus, and non-transitory computer-readable media described in this specification may further include operations, features, means, or instructions for performing a random access procedure on the second BWP based on switching to the second BWP.

[0020]

[0020] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, means, or instructions for transmitting a first message of a random access procedure, determining that a threshold number of attempts to transmit the first message have been met, and declaring an RLF or switching to a third BWP or a combination thereof based on the threshold number of attempts to transmit the first message having been met.

[0021]

[0021] Some examples of the methods, apparatus, and non-transitory computer-readable media described in this specification may further include operations, features, means, or instructions for determining that the number of uplink LBT failures for the second BWP exceeds a threshold, switching to a third BWP based on the number of uplink LBT failures for the second BWP exceeding the threshold, and aborting the random access procedure on the second BWP.

[0022]

[0022] Some examples of the methods, apparatuses, and non-transitory computer-readable media described in this specification may further include operations, features, means, or instructions for determining that uplink LBT failures for a number of first BWPs occur in a PSCell and transmitting a dedicated cause value for the number of uplink LBT failures for the first BWPs in a secondary cell group (SCG) failure message.

[0023] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the dedicated reason value may include the number of switched BWPs attempted.

[0024]

[0024] Some examples of the methods, apparatuses, and non-transitory computer-readable media described in this specification may further include operations, features, means, or instructions for determining that an uplink LBT failure for a number of first BWPs occurs on an SCell and transmitting a MAC CE indicating the uplink LBT failure on a PCell or an additional SCell.

[0025]

[0025] In some examples of the methods, apparatus, and non-transitory computer-readable media described in this specification, transmitting a MAC CE may include operations, features, means, or instructions for determining that an SCell includes a set of BWPs including a first BWP, and transmitting a MAC CE on an additional BWP in a subband for an SCell different from the first BWP.

[0026]

[0026] Some examples of the methods, apparatus, and non-transitory computer-readable media described in this specification may further include operations, features, means, or instructions for determining to switch to a second BWP based on the number of failures associated with the set of LBT procedures for the first BWP meeting a threshold.

[0027]

[0027] Some examples of the methods, apparatus, and non-transitory computer-readable media described in this specification may further include an operation, feature, means, or instruction for performing a master cell group (MCG) recovery procedure via a secondary node (SN) based on a determination that the number of uplink LBT failures for the second BWPs meets a threshold and that uplink LBT failures for that number of second BWPs occur on the PCell.

[0028]

[0028] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, performing an MCG recovery procedure via the SN may include an operation, feature, means, or instruction for sending to the SN an indication of a failure for the PCell based on the number of uplink LBT failures for the second BWP exceeding a threshold.

[0029]

[0029] Some examples of the methods, apparatus, and non-transitory computer-readable media described in this specification may further include operations, features, means, or instructions for performing one or more LBT procedures for the second BWP and switching to a third BWP in accordance with a BWP switching configuration and switching parameters based on the number of failures associated with the one or more LBT procedures for the second BWP.

[0030] A method of wireless communication in a base station is described, and may include transmitting a BWP switch configuration message to a UE, the BWP switch configuration message including switching parameters, receiving a first uplink transmission in the first BWP from the UE, and receiving an uplink transmission in a second BWP from the UE based on the switching parameters and an uplink LBT failure.

[0031] An apparatus for wireless communication in a base station is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to: send a BWP switch configuration message to a UE, the BWP switch configuration message including switching parameters; receive a first uplink transmission in the first BWP from the UE; and receive an uplink transmission in a second BWP from the UE based on the switching parameters and an uplink LBT failure.

[0032] Another apparatus for wireless communication in a base station is described, which may include means for transmitting a BWP switch configuration message to a UE, the BWP switch configuration message including switching parameters, means for receiving a first uplink transmission in a first BWP from the UE, and means for receiving an uplink transmission in a second BWP from the UE based on the switching parameters and an uplink LBT failure.

[0033] A non-transitory computer-readable medium storing code for wireless communications in a base station is described, and may include instructions executable by a processor to: send a BWP switch configuration message to a UE, the BWP switch configuration message including switch parameters; receive a first uplink transmission in the first BWP from the UE; and receive an uplink transmission in a second BWP from the UE based on the switch parameters and an uplink LBT failure.

[0034]

[0034] Some examples of the methods, apparatuses, and non-transitory computer-readable media described in this specification may further include an operation, feature, means, or instruction for receiving from the UE a dedicated reason value for the number of uplink LBT failures for the first BWP in an SCG failure message, where the dedicated reason value includes the number of switched BWPs attempted.

[0035]

[0035] Some examples of the methods, apparatuses, and non-transitory computer-readable media described in this specification may further include an operation, feature, means, or instruction for receiving a MAC CE from the UE indicating the number of uplink LBT failures for the first BWP on the PCell or SCell.

[0036]

[0036] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the MAC CE may be received on an additional BWP in a subband for a SCell different from the first BWP.

[0037]

[0037] Some examples of the methods, apparatus, and non-transitory computer-readable media described in this specification may further include an operation, feature, means, or instruction for receiving, from the SN, an indication of a failure for the PCell based on the number of uplink LBT failures for the first BWP exceeding a threshold.

[0038]

[0038] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the switching parameters may include the number of BWP switches, an indication of which BWP may be switched to after a failure of another BWP, a priority order for a set of BWPs in a BWP switching configuration message, an indication to switch to a BWP in a different subband, an indication that the same BWP may be used multiple times for switching, a threshold time between switching to the same BWP, or a combination thereof. [Brief explanation of the drawings]

[0039] [Figure 1]

[0039] FIG. 1 illustrates an example of a system for wireless communication supporting uplink listen-before-talk (LBT) failure recovery, according to aspects of the present disclosure. [Figure 2]

[0040] FIG. 1 illustrates an example of a bandwidth portion (BWP) switching configuration supporting uplink LBT failure recovery, according to aspects of the present disclosure. [Figure 3]

[0041] FIG. 1 illustrates an example of a wireless communication system that supports uplink LBT failure recovery, according to aspects of the present disclosure. [Figure 4]

[0042] FIG. 1 illustrates an example process flow for supporting uplink LBT failure recovery, according to aspects of the present disclosure. [Figure 5]

[0043] 1 is a block diagram of a device supporting uplink LBT failure recovery according to an aspect of the present disclosure. [Figure 6] 1 is a block diagram of a device supporting uplink LBT failure recovery according to an aspect of the present disclosure. [Figure 7]

[0044] 1 is a block diagram of a user equipment (UE) communications manager supporting uplink LBT failure recovery, according to an aspect of the present disclosure. [Figure 8]

[0045] FIG. 1 illustrates a diagram of a system including a device that supports uplink LBT failure recovery, according to an aspect of the present disclosure. [Figure 9]

[0046] 1 is a block diagram of a device supporting uplink LBT failure recovery according to an aspect of the present disclosure. [Figure 10] 1 is a block diagram of a device supporting uplink LBT failure recovery according to an aspect of the present disclosure. [Figure 11]

[0047] 1 is a block diagram of a base station communication manager supporting uplink LBT failure recovery according to an aspect of the present disclosure. [Figure 12]

[0048] FIG. 1 illustrates a diagram of a system including a device that supports uplink LBT failure recovery, according to an aspect of the present disclosure. [Figure 13]

[0049] 10 is a flowchart illustrating a method for supporting uplink LBT failure recovery according to an aspect of the present disclosure. [Figure 14] 10 is a flowchart illustrating a method for supporting uplink LBT failure recovery according to an aspect of the present disclosure. [Figure 15]10 is a flowchart illustrating a method for supporting uplink LBT failure recovery according to an aspect of the present disclosure. [Figure 16] 10 is a flowchart illustrating a method for supporting uplink LBT failure recovery according to an aspect of the present disclosure. [Figure 17] 10 is a flowchart illustrating a method for supporting uplink LBT failure recovery according to an aspect of the present disclosure. [Figure 18] 10 is a flowchart illustrating a method for supporting uplink LBT failure recovery according to an aspect of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0040]

[0050] In some wireless communication systems (e.g., New Radio Unlicensed (NR-U) bands), a UE may perform a listen-before-talk (LBT) procedure to determine whether the channel is unoccupied for uplink transmission and may transmit an uplink transmission after determining that the LBT procedure is successful (e.g., the channel is clear). In the case of a dual connectivity configuration (e.g., or carrier aggregation configuration), if the UE detects consistent failures for the LBT procedure (e.g., a number of failed LBT procedures exceeding a configured number of attempts) on a current uplink bandwidth portion (BWP) on a primary cell (PCell) (e.g., or primary-secondary cell (PSCell)), the UE may switch to another BWP for recovery. However, some techniques for switching to another BWP may not include parameters for switching. For example, the UE may attempt to switch to a BWP in the same subband as the failed BWP, may attempt to switch to a BWP in a subband adjacent to the failed BWP, or may attempt to switch to the same BWP that was previously attempted and already failed. Thus, the UE may inefficiently try different BWPs before finding a clear channel to use for uplink transmission, which may unnecessarily increase latency and delay uplink transmission.

[0041]

[0051] As described herein, a base station (or network) may indicate different parameters (e.g., switching parameters) for a UE to switch between different BWPs based on identifying consistent LBT failures for the BWP. For example, the base station may indicate the number of BWP switches for the UE (e.g., the maximum number of switches the UE can perform, the minimum number of switches, a fixed number of switches, etc.), whether a BWP can be switched after another BWP failure, the priority order in which BWPs are to be switched, switching to a BWP in a different subband from the failed BWP, whether the same BWP can be switched multiple times, the maximum time between switches to the same BWP, or a combination thereof. Thus, based on the information indicated using the switching parameters from the base station, the UE may select or identify a second BWP and attempt to communicate with the base station using the second BWP.

[0042]

[0052] In some cases, the UE may then perform a random access procedure (e.g., a random access channel (RACH) procedure) for the second BWP (e.g., the BWP to which the UE switches). If a RACH failure occurs in the second BWP, the UE may declare a radio link failure (RLF) or switch to a different BWP (e.g., a third BWP). Furthermore, if the UE identifies a consistent LBT failure on the second BWP, the UE may switch to a different BWP and abort the RACH for the second BWP. In some cases, if a consistent LBT failure occurs in a PSCell, the UE may signal a dedicated cause value (e.g., including the number of switched BWPs) in a secondary cell group (SCG) failure message for the PSCell. Additionally or alternatively, if a consistent LBT failure occurs in a BWP in a secondary cell (SCell) (e.g., in the case of a dual connectivity or carrier aggregation configuration), the UE may transmit a medium access control (MAC) control element (CE) on the PCell, the additional SCell, or the additional BWP for the SCell. Additionally or alternatively, if a consistent LBT failure occurs in the PCell, the UE may perform master cell group (MCG) recovery through a secondary node (SN) (e.g., a secondary base station) that forwards the recovery to the base station (e.g., a master node (MN), PCell, etc.).

[0043]

[0053] Aspects of the present disclosure are initially described in the context of a wireless communication system. Further, aspects of the present disclosure are illustrated through BWP switching configurations, additional wireless communication systems, and process flows. Aspects of the present disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts relating to uplink LBT failure recovery.

[0044]

[0054] 1 illustrates an example of a wireless communication system 100 supporting uplink LBT failure recovery according to an aspect of the present disclosure. The wireless communication system 100 may include one or more base stations 105, one or more UEs 115, and a core network 130. In some cases, the wireless communication system 100 may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. In some examples, the wireless communication system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission-critical) communications, low-latency communications, communications using low-cost and low-complexity devices, or any combination thereof.

[0045]

[0055] The base stations 105 may be dispersed throughout a geographic area to form the wireless communication system 100 and may be devices of different forms or with different capabilities. The base stations 105 and the UEs 115 may communicate wirelessly via one or more communication links 125. Each base station 105 may provide a coverage area 110 over which the UEs 115 and the base stations 105 may establish one or more communication links 125. The coverage area 110 may be an example of a geographic area over which the base stations 105 and the UEs 115 may support communication of signals according to one or more radio access technologies.

[0046]

[0056] The UEs 115 may be dispersed throughout the coverage area 110 of the wireless communication system 100, and each UE 115 may be fixed, or mobile, or both at different times. The UEs 115 may be devices of different forms or with different capabilities. Some example UEs 115 are shown in FIG. 1. The UEs 115 described herein may be able to communicate with various types of devices, such as other UEs 115, base stations 105, or network equipment (e.g., core network nodes, relay devices, integrated access and backhaul (IAB) nodes, or other network equipment), as shown in FIG. 1.

[0047]

[0057] The base stations 105 may communicate with the core network 130, with each other, or both. For example, the base stations 105 may interface with the core network 130 through one or more backhaul links 120 (e.g., via an S1, N2, N3, or other interface). The base stations 105 may communicate with each other directly (e.g., directly between the base stations 105), or indirectly (e.g., via the core network 130), or both via the backhaul links 120 (e.g., via an X2, Xn, or other interface). In some examples, the backhaul links 120 may be or include one or more wireless links.

[0048]

[0058] One or more of the base stations 105 described herein may include or be referred to by those skilled in the art as a base transceiver station, radio base station, access point, radio transceiver, Node B, eNode B (eNB), Next Generation Node B or Giga Node B (both may be referred to as gNB), Home Node B, Home eNode B, or other suitable terminology.

[0049]

[0059] The UE 115 may include or be referred to as a mobile device, wireless device, remote device, handheld device, or subscriber device, or some other suitable terminology, where a “device” may also be referred to as a unit, station, terminal, or client, among other examples. The UE 115 may also include or be referred to as a personal electronic device, such as a cellular phone, a personal digital assistant (PDA), a tablet computer, a laptop computer, or a personal computer. In some examples, the UE 115 may include or be referred to as a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a machine-type communication (MTC) device, among other examples, which may be implemented in various objects such as an appliance, a vehicle, or a meter, among other examples.

[0050]

[0060] The UEs 115 described herein may be capable of communicating with various types of devices, such as other UEs 115, which may act as relays at times, as well as base stations 105 and network equipment, including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, among other examples, as shown in FIG. 1.

[0051]

[0061] The UE 115 and the base station 105 may communicate wirelessly with each other by one or more communication links 125 via one or more carriers. The term “carrier” may refer to a set of radio frequency spectrum resources having a defined physical layer structure for supporting the communication link 125. For example, a carrier used for the communication link 125 may include a portion of a radio frequency spectrum band (e.g., BWP) operated according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR). Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information), control signaling that coordinates the operation of the carrier, user data, or other signaling. The wireless communication system 100 may support communication with the UE 115 using carrier aggregation or multi-carrier operation. The UE 115 may be configured with multiple downlink component carriers and one or more uplink component carriers according to a carrier aggregation configuration. Carrier aggregation can be used with both frequency division duplex (FDD) and time division duplex (TDD) component carriers.

[0052]

[0062] In some examples (e.g., in carrier aggregation configurations), a carrier may also have acquisition or control signaling that coordinates the operation of other carriers. Carriers may be associated with frequency channels (e.g., Evolved Universal Mobile Telecommunications System Terrestrial Radio Access Network (E-UTRA) Absolute Radio Frequency Channel Numbers (EARFCNs)) and may be arranged according to a channel raster for discovery by UEs 115. A carrier may operate in a standalone mode, where initial acquisition and connection may be made by UEs 115 over the carrier, or the carrier may operate in a non-standalone mode, where a connection is established using a different carrier (e.g., of the same or different radio access technology).

[0053]

[0063] The communication links 125 shown in the wireless communication system 100 may include uplink transmissions from the UE 115 to the base station 105 or downlink transmissions from the base station 105 to the UE 115. A carrier may carry downlink or uplink communications (e.g., in FDD mode) or may be configured to carry downlink and uplink communications (e.g., in TDD mode).

[0054]

[0064] A carrier may be associated with a particular bandwidth of the radio frequency spectrum, and in some examples, the carrier bandwidth may be referred to as the carrier or the “system bandwidth” of the wireless communication system 100. For example, the carrier bandwidth may be one of several predetermined bandwidths (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 megahertz (MHz)) for a carrier of a particular radio access technology. The devices of the wireless communication system 100 (e.g., the base station 105, the UE 115, or both) may have a hardware configuration that supports communication over a particular carrier bandwidth or may be configurable to support communication over one of a set of carrier bandwidths. In some examples, the wireless communication system 100 may include a base station 105 or a UE 115 that supports simultaneous communication over carriers associated with multiple carrier bandwidths. In some examples, each served UE 115 may be configured to operate over a portion (e.g., a sub-band, BWP) or all of the carrier bandwidth.

[0055]

[0065] A signal waveform transmitted over a carrier may be composed of multiple subcarriers (e.g., using a multicarrier modulation (MCM) technique such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform extended OFDM (DFT-S-OFDM)). In a system utilizing MCM techniques, a resource element may be composed of one symbol period (e.g., the duration of one modulation symbol) and one subcarrier, where the symbol period and subcarrier spacing have an inverse relationship. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the coding rate of the modulation scheme, or both). Thus, the more resource elements and the higher the order of the modulation scheme that the UE 115 receives, the higher the data rate of the UE 115 may be. Wireless communication resources may refer to a combination of radio frequency spectrum resources, time resources, and spatial resources (e.g., spatial layers or beams), and the use of multiple spatial layers may further increase the data rate or data integrity for communications with the UE 115.

[0056]

[0066] The time interval for the base station 105 or the UE 115 may be, for example, T s =1 / (Δf max N f ) seconds, where Δf max may represent the maximum supported subcarrier spacing, and N f may represent the maximum supported discrete Fourier transform (DFT) size. The communication resource time intervals may be organized according to radio frames, each having a specified duration (e.g., 10 milliseconds (ms)). Each radio frame may be identified by a system frame number (SFN) (e.g., ranging from 0 to 1023).

[0057]

[0067] Each frame may include multiple consecutively numbered subframes or slots, and each subframe or slot may have the same duration. In some examples, a frame may be divided into subframes (e.g., in the time domain), and each subframe may be further divided into several slots. Alternatively, each frame may include a variable number of slots, and the number of slots may depend on the subcarrier spacing. Each slot may include several symbol periods (e.g., depending on the length of a cyclic prefix prepended to each symbol period). In some wireless communication systems 100, a slot may be further divided into multiple minislots containing one or more symbols. Excluding the cyclic prefix, each symbol period may include one or more (e.g., N f ) sampling period. The duration of a symbol period may depend on the subcarrier spacing or frequency operating band.

[0058]

[0068] A subframe, slot, minislot, or symbol may be the smallest scheduling unit (e.g., in the time domain) of the wireless communication system 100 and may be referred to as a transmission time interval (TTI). In some examples, the TTI duration (e.g., the number of symbol periods in a TTI) may be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communication system 100 may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs)).

[0059]

[0069] Physical channels may be multiplexed on carriers according to various techniques. Physical control channels and physical data channels may be multiplexed on downlink carriers using, for example, one or more of time division multiplexing (TDM), frequency division multiplexing (FDM), or hybrid TDM-FDM techniques. A control region (e.g., a control resource set (CORESET)) for a physical control channel may be defined by several symbol periods and may span the entire system bandwidth of a carrier or a subset of the system bandwidth. One or more control regions (e.g., CORESET) may be configured for a set of UEs 115. For example, one or more of the UEs 115 may monitor or search the control region for control information according to one or more search space sets, and each search space set may include one or more control channel candidates within one or more aggregation levels configured in a cascaded manner. The aggregation level for the control channel candidates may refer to several control channel resources (e.g., control channel elements (CCEs)) associated with coded information for a control information format having a given payload size. The search space sets may include a common search space set configured for sending control information to multiple UEs 115 and a UE-specific search space set for sending control information to a particular UE 115.

[0060]

[0070] Each base station 105 may provide communication coverage via one or more cells, e.g., macro cells, small cells, hot spots, or other types of cells, or any combination thereof. The term “cell” may refer to a logical communication entity used for communication with the base station 105 (e.g., over a carrier) and may be associated with an identifier (e.g., a physical cell identifier (PCID), a virtual cell identifier (VCID), or other) for distinguishing neighboring cells. In some examples, a cell may also refer to a geographic coverage area 110 or a portion (e.g., a sector) of a geographic coverage area 110 in which the logical communication entity operates. Such a cell may range from a smaller area (e.g., a structure, a subset of a structure) to a larger area, depending on various factors such as the capabilities of the base station 105. For example, a cell may be or include a building, a subset of a building, or an exterior space between or overlapping with the geographic coverage area 110, among other examples.

[0061]

[0071] A macro cell generally covers a relatively large geographic area (e.g., a few kilometers in radius) and may allow unrestricted access by UEs 115 with a service subscription with the network provider that supports the macro cell. Small cells may be associated with lower-power base stations 105 compared to macro cells, and the small cells may operate within the same or different (e.g., licensed, unlicensed) frequency bands as the macro cell. A small cell may provide unrestricted access to UEs 115 with a service subscription with the network provider, or may provide restricted access to UEs 115 that have an association with the small cell (e.g., UEs 115 in a closed subscriber group (CSG), UEs 115 associated with users at home or in the office). A base station 105 may support one or more cells and may also support communication via one or more cells using one or more component carriers.

[0062]

[0072] In some cases, the wireless communication system 100 may utilize both licensed and unlicensed radio frequency spectrum bands. For example, the wireless communication system 100 may employ license-assisted access (LAA), LTE-unlicensed (LTE-U), or NR technology in an unlicensed band, such as the 5 GHz ISM band. When operating in an unlicensed radio frequency spectrum band, wireless devices, such as the base station 105 and the UE 115, may employ LBT procedures to ensure that the frequency channel is clear before transmitting data. In some cases, operation in the unlicensed band may be based on a carrier aggregation configuration with component carriers operating in a licensed band (e.g., LAA). Operation in the unlicensed spectrum may include downlink transmission, uplink transmission, peer-to-peer transmission, or a combination thereof. Duplexing in the unlicensed spectrum may be based on FDD, TDD, or a combination of both.

[0063]

[0073] In some cases, the base stations 105 are mobile and may therefore provide communication coverage to moving geographic coverage areas 110. In some cases, different geographic coverage areas 110 associated with different technologies may overlap, but the different geographic coverage areas 110 may be supported by the same base station 105. In other examples, overlapping geographic coverage areas 110 associated with different technologies may be supported by different base stations 105. The wireless communication system 100 may include a heterogeneous network in which different types of base stations 105 provide coverage to various geographic coverage areas 110, for example, using the same or different radio access technologies.

[0064]

[0074] The wireless communication system 100 may be configured to support ultra-reliable or low-latency communications, or various combinations thereof. For example, the wireless communication system 100 may be configured to support ultra-reliable low-latency communications (URLLC) or mission-critical communications. The UE 115 may be designed to support ultra-reliable, low-latency, or critical functions (e.g., mission-critical functions). Ultra-reliable communications may include private or group communications and may be supported by one or more mission-critical services, such as mission-critical push-to-talk (MCPTT), mission-critical video (MCVideo), or mission-critical data (MCData). Support for mission-critical functions may include service prioritization, and the mission-critical services may be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, mission-critical, and ultra-reliable low-latency may be used interchangeably herein.

[0065]

[0075] In some examples, the UE 115 may also be able to communicate directly with other UEs 115 via a device-to-device (D2D) communication link 135 (e.g., using a peer-to-peer (P2P) or D2D protocol). One or more UEs 115 utilizing D2D communication may be within the geographic coverage area 110 of the base station 105. Other UEs 115 in such a group may be outside the geographic coverage area 110 of the base station 105 or otherwise unable to receive transmissions from the base station 105. In some examples, a group of UEs 115 communicating via D2D communication may utilize a one-to-many (1:M) system in which each UE 115 transmits to every other UE 115 in the group. In some examples, the base station 105 facilitates scheduling of resources for D2D communication. In other cases, D2D communication is performed between UEs 115 without the involvement of the base station 105.

[0066]

[0076] The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 may be an evolved packet core (EPC) or 5G core (5GC) that may include at least one control plane entity (e.g., a mobility management entity (MME), an access and mobility management function (AMF)) that manages access and mobility, and at least one user plane entity (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), or a user plane function (UPF)) that routes packets or interconnections to external networks. The control plane entity may manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management, for the UEs 115 served by the base stations 105 associated with the core network 130. User IP packets may be forwarded through the user plane entity, which may provide IP address allocation and other functions. The user plane entity may be connected to a network operator's IP services 150. The operator's IP services 150 may include access to the Internet, an intranet, an IP Multimedia Subsystem (IMS), or packet-switched streaming services.

[0067]

[0077] Some of the network devices, such as the base station 105, may include sub-components such as an access network entity 140, which may be an example of an access node controller (ANC). Each access network entity 140 may communicate with the UE 115 through one or more other access network transmitting entities 145, which may be referred to as a radio head, a smart radio head, or a transmit / receive point (TRP). Each access network transmitting entity 145 may include one or more antenna panels. In some configurations, various functions of each access network entity 140 or base station 105 may be distributed across various network devices (e.g., radio heads and ANCs) or integrated into a single network device (e.g., the base station 105).

[0068]

[0078] The wireless communication system 100 may operate using one or more frequency bands typically ranging from 300 megahertz (MHz) to 300 gigahertz (GHz). The 300 MHz to 3 GHz region is generally known as the ultra-high frequency (UHF) region or decimeter band because wavelengths range in length from approximately 1 decimeter to 1 meter. Although UHF waves may be blocked or redirected by buildings and environmental features, these waves may penetrate structures sufficiently for a macrocell to serve UEs 115 located indoors. Transmission of UHF waves may be associated with smaller antennas and shorter distances (e.g., less than 100 kilometers) compared to transmissions using smaller frequencies and longer waves in the high frequency (HF) or very high frequency (VHF) portions of the spectrum below 300 MHz.

[0069]

[0079] The wireless communication system 100 may utilize both licensed and unlicensed radio frequency spectrum bands. For example, the wireless communication system 100 may employ Licensed Assisted Access (LAA), LTE Unlicensed (LTE-U), or NR technology in an unlicensed band, such as the 5 GHz Industrial, Scientific, and Medical (ISM) band. Devices such as the base station 105 and the UE 115 may employ carrier sensing for collision detection and avoidance when operating in the unlicensed radio frequency spectrum band. In some examples, operation in the unlicensed band may be based on a carrier aggregation configuration with component carriers operating in a licensed band (e.g., LAA). Operation in the unlicensed spectrum may include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, among other examples.

[0070]

[0080] The base station 105 or the UE 115 may be equipped with multiple antennas that can be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. The antennas of the base station 105 or the UE 115 may be arranged in one or more antenna arrays or antenna panels that can support MIMO operation or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located in an antenna assembly such as an antenna tower. In some examples, antennas or antenna arrays associated with the base station 105 may be located in various geographic locations. The base station 105 may have an antenna array with several rows and columns of antenna ports that the base station 105 can use to support beamforming of communications with the UE 115. Similarly, the UE 115 may have one or more antenna arrays that can support various MIMO or beamforming operations. Additionally or alternatively, the antenna panel may support radio frequency beamforming of signals transmitted through the antenna ports.

[0071]

[0081] Beamforming, sometimes referred to as spatial filtering, directional transmission, or directional reception, is a signal processing technique that may be used at a transmitting or receiving device (e.g., base station 105, UE 115) to shape or steer an antenna beam (e.g., transmit beam, receive beam) along a spatial path between the transmitting and receiving devices. Beamforming may be achieved by combining signals communicated via antenna elements of an antenna array such that some signals propagating in a particular orientation relative to the antenna array experience constructive interference, while others experience destructive interference. Adjusting signals communicated via antenna elements may include the transmitting or receiving device applying an amplitude offset, a phase offset, or both to signals carried via antenna elements associated with the device. The adjustment associated with each of the antenna elements may be defined by a beamforming weight set associated with a particular orientation (e.g., relative to the antenna array of the transmitting or receiving device, or to some other orientation).

[0072]

[0082] The wireless communication system 100 may be a packet-based network operating according to a layered protocol stack. In the user plane, communications at the bearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based. The Radio Link Control (RLC) layer may perform packet segmentation and reassembly for communications on logical channels. The MAC layer may perform priority handling and multiplexing of logical channels onto transport channels. The MAC layer may also use error detection, error correction, or both to support retransmissions at the MAC layer to improve link efficiency. In the control plane, the Radio Resource Control (RRC) protocol layer may establish, configure, and maintain an RRC connection between the UE 115 and the base station 105 or core network 130, which supports radio bearers for user plane data. In the physical layer, transport channels may be mapped to physical channels.

[0073]

[0083] In some wireless communication systems, the UE 115 may support carrier aggregation or dual connectivity, or both, where the UE 115 communicates with multiple cells simultaneously. For example, the UE may communicate with a first base station 105 (e.g., a PCell) and a second base station 105 (e.g., an SCell) simultaneously. Additionally or alternatively, a single base station 105 may include multiple cells (e.g., both a PCell and an SCell), where the UE 115 communicates with two or more cells simultaneously on the single base station 105. In some cases, one or more of the cells may be grouped into a PCell group (e.g., an MCG), which may include a PCell and one or more SCells. Furthermore, one or more SCells may be grouped into an SCell group (e.g., an SCG). In some cases, a PSCell may be configured for one or more SCells. Communications on each cell group may be unrelated to one another.

[0074]

[0084] In communication between the UE 115 and the base station 105, the available bandwidth of a frequency for communication may be divided into BWPs, which are subsets of the available bandwidth of a frequency. A BWP may be a bandwidth over which the UE 115 can transmit and receive information. In conventional systems, a maximum number of four BWPs may be configured for the UE 115. In some cases, the UE 115 may monitor a single active BWP at a time (e.g., on a PCell). Additionally, on an SCell, the UE 115 may have multiple active BWPs at a given time.

[0075]

[0085] In some cases, a carrier may be divided into one or more BWPs based on the size of the carrier exceeding a bandwidth threshold (e.g., greater than 20 MHz). Each of the BWPs may further include one or more subchannels (e.g., subbands), where each subchannel is of the same bandwidth (e.g., 20 MHz). Thus, each BWP may vary in size (e.g., in multiples of 20 MHz) based on the number of subchannels located therein. The BWPs and corresponding subchannels may be portions of a shared radio frequency (RF) spectrum (e.g., unlicensed or shared licensed spectrum, such as NR-U) in which one or more wireless devices (e.g., base station 105 and UE 115) compete. A wireless device (e.g., base station 105, UE 115, etc.) may determine which subchannels are available for communication with other wireless devices based on an LBT procedure that indicates whether ongoing communication exists on each of the subchannels.

[0076]

[0086] For example, prior to transmitting one or more uplink signals, the UE 115 may perform an LBT (e.g., an LBT procedure, clear channel assessment (CCA), etc.) based on communicating with the base station 105 in an unlicensed band (e.g., an unlicensed frequency band, NR-U, etc.). In some cases, the LBT may include the UE 115 listening to uplink resources (e.g., indicated by an uplink grant from the base station 105) for transmitting one or more uplink signals to determine whether the channel is clear before attempting to transmit on the uplink resources. Thus, if the UE 115 detects a signal (e.g., above a threshold power value) on the uplink resource during the LBT, the UE 115 may refrain from transmitting the uplink signal. Alternatively, if the UE 115 does not detect a signal, the UE 115 may determine that the LBT was successful and may proceed to transmit the uplink signal.

[0077]

[0087] Thus, in some wireless communication systems (e.g., NR-U), the UE 115 may perform an LBT for an uplink transmission and may transmit the uplink transmission after the LBT is successful. In some cases, a detection and recovery mechanism may be used by the UE 115 when a consistent uplink LBT failure occurs. The consistent uplink LBT failure may be considered a trigger event for the UE 115 based on the number of consecutive LBT failures occurring in succession (e.g., a configurable number of consecutive LBT failures indicated to the UE 115 by the base station 105, etc., via RRC signaling or pre-configured in the UE 115). For example, in the case of a primary cell (e.g., a PCell or PSCell), if the UE 115 detects a consistent LBT failure on an existing uplink BWP that is being monitored or intended to be used by the UE 115, the UE 115 may switch to another BWP for recovery.

[0078]

[0088] As part of this detection and recovery mechanism, the MAC layer (e.g., and additional higher layers) may rely on receiving a notification of an uplink LBT failure from the physical layer to detect a consistent uplink LBT failure. The UE 115 may then switch to another BWP and, if there is another BWP with configured RACH resources (e.g., physical RACH (PRACH) resources), initiate a RACH procedure (e.g., a random access procedure) upon declaration of a consistent LBT failure on the PCell or PSCell. In some cases, if a consistent uplink LBT failure is detected on the PCell and uplink LBT failure is detected on N possible BWPs, the UE shall perform RLF recovery. Additionally or alternatively, when a consistent uplink LBT failure is detected on the PSCell, the UE 115 may notify the MN (e.g., base station 105) of the consistent uplink LBT failure via an SCG Failure Information procedure after detecting consistent uplink LBT failures on N BWPs. In some cases, N may represent the number of configured BWPs with configured PRACH resources for the UE 115 to use. For example, N may be indicated to the UE 115 by the base station 105 (e.g., the MN, the scheduling base station 105, etc.). If N is greater than 1, the UE 115 may select the next BWP to switch to based on the UE implementation. Furthermore, when a consistent uplink LBT failure is detected on an SCell, the UE 115 may send a MAC CE to report the consistent uplink LBT failure to the node to which the SCell belongs (e.g., a secondary base station, an SN, etc.).

[0079]

[0089] However, with the detection and recovery mechanisms described previously, no parameters are indicated to the UE 115 for switching BWPs, and it is up to the UE 115 to decide which BWP to switch to. For example, the UE 115 may attempt to switch to a BWP in the same subband as the failed BWP, or to a BWP in a subband adjacent to the failed BWP, or to switch to the same BWP that was previously attempted and already failed. Thus, the UE may inefficiently attempt different BWPs that also have a higher probability of failing before finding a clear channel to use for uplink transmission, which may unnecessarily increase latency and delay uplink transmission.

[0080]

[0090] The wireless communication system 100 may include efficient techniques for identifying a BWP to switch to after the UE 115 identifies a consistent uplink LBT failure on a first BWP based on parameters indicated by the base station 105. For example, the base station 105 may transmit to the UE 115 switching parameters that the UE 115 then uses to switch to a second BWP based on identifying a consistent uplink LBT failure on the first BWP. In some cases, the switching parameters may indicate the number of BWP switches for the UE (e.g., a maximum number of switches the UE can perform, a minimum number of switches, a fixed number of switches, etc.), whether a BWP can be switched after the failure of another BWP, a priority order in which BWPs are to be switched, switching to a BWP in a different subband from the failed BWP, whether the same BWP can be switched to multiple times, a maximum time between switches to the same BWP, or a combination thereof. Thereafter, after selecting the second BWP, the UE 115 may attempt to use the second BWP to send an uplink transmission to the base station 105 (e.g., after performing a RACH procedure). Additionally, the UE 115 may send a consistent uplink LBT failure indication to the base station 105 associated with the failed BWP based on the type of cell using that failed BWP.

[0081]

[0091] 2 illustrates an example of a BWP switching configuration 200 supporting uplink LBT failure recovery according to aspects of the present disclosure. In some examples, the BWP switching configuration 200 may implement aspects of the wireless communication system 100. For example, the BWP switching configuration 200 may include a base station 105-a and a UE 115-a, which may be examples of the corresponding base station 105 and UE 115, respectively, described with reference to FIG. 1. In some cases, the base station 105-a and the UE 115-a may communicate over resources of a carrier 205. Furthermore, the carrier 205 may include resources in an unlicensed band (e.g., NR-U communication), which may be divided into one or more BWPs 220 as described herein.

[0082]

[0092] In some cases, based on communicating in an unlicensed band, the UE 115-a may perform the LBT 210 in an initial attempt to determine whether resources are available in the first BWP 220-a of the carrier 205 before transmitting an uplink message to the base station 105-a. However, the resources may be occupied and may be used by another UE 115, the base station 105, or an additional wireless device. For example, the UE 115-a may determine that a consistent uplink LBT failure has occurred in the first BWP 220-a based on the number of consecutive LBT failures satisfying a threshold. In some cases, this threshold for the number of consecutive LBT failures to be considered a consistent uplink LBT failure is configurable and may be indicated to the UE 115-a by the base station 105-a (e.g., via RRC signaling) or may be pre-configured in the UE 115-a. Thus, after identifying a consistent LBT failure on a first BWP 220-a, the UE 115-a may switch to a different BWP 220 and attempt a subsequent LBT 225 on this different BWP 220.

[0083]

[0093] Rather than leaving it up to the UE implementation to decide which BWP 220 to switch to, the base station 105-a may send switching parameters 215 to the UE 115-a. The UE 115-a may then use the information included in the switching parameters 215 to perform a BWP switch 230, determine the next BWP 220 to switch to, and attempt to communicate with the base station 105-a. In some cases, the number (N) of BWPs 220 available for the UE 115-a to switch to may be indicated by the base station 105-a to the UE 115-a. As described herein, N may represent the number of configured BWPs 220 with configured PRACH resources for the UE 115 to use. 2 shows five BWPs 220 (e.g., N=5 with a first BWP 220-a, a second BWP 220-b, a third BWP 220-c, a fourth BWP 220-d, and a fifth BWP 220-e), the number of BWPs 220 may be more or less than five. Furthermore, while the five BWPs 220 are shown as being contiguous in the frequency domain (e.g., each BWP 220 appears adjacent to another BWP 220), it should be understood that the BWPs 220 may be spread among the resources of the unlicensed band of the carrier 205.

[0084]

[0094] In some cases, the switch parameters 215 may indicate a configured number of BWP switches 230 for the UE 115-a. For example, the number of BWP switches 230 may represent a maximum number of BWP switches 230 that the UE 115-a can perform (e.g., before determining an RLF) (e.g., an upper threshold), a minimum number of BWP switches 230 that the UE 115-a will perform (e.g., a lower threshold), or a fixed number of BWP switches 230 for the UE 115-a. If the number of BWP switches 230 is not included (e.g., not configured) in the switch parameters 215, the UE 115-a may determine the number of BWP switches 230 to perform, which may be performed autonomously. As shown in the example of FIG. 2, the number of BWP switches 230 may be three (e.g., a first BWP switch 230-a, a second BWP switch 230-b, and a third BWP switch 230-c).

[0085]

[0095] Additionally or alternatively, switching parameters 215 may indicate whether BWPs 220 can be switched after a consistent uplink LBT failure is identified on another BWP 220. For example, switching parameters 215 may indicate that UE 115-a can use a third BWP 220-c after a consistent uplink LBT failure is identified on a first BWP 220-a. Additionally or alternatively, switching parameters 215 may indicate multiple BWPs 220 that UE 115-a can use after a consistent uplink LBT failure is identified on the first BWP 220-a, and UE 115-a may then select one of the multiple BWPs 220 to use (e.g., based on additional information included in switching parameters 215, based on the UE implementation, etc.). For example, the switching parameters 215 may indicate that the UE 115-a can use the third BWP 220-c, the fourth BWP 220-d, or the fifth BWP 220-e after a consistent uplink LBT failure is identified on the first BWP 220-a, and the UE 115-a may select the fourth BWP 220-d for use as part of the first BWP switching 230-a.

[0086]

[0096] In some cases, the switching parameters 215 may indicate one or more BWPs 220 that the UE 115-a cannot use after a consistent uplink LBT failure is identified on another BWP 220, and the UE 115-a may decide to switch to the unindicated BWP 220. Additionally or alternatively, the switching parameters 215 may indicate, for each of the N BWPs 220, whether each BWP 220 can be switched to after a failure of another BWP 220. In some cases, the switching parameters 215 may include a configuration of a priority order to use for each BWP 220. Thus, the UE 115-a may switch to a BWP 220 based on which BWP 220 has the highest priority.

[0087]

[0097] Additionally or alternatively, the switching parameters 215 may include an indication of a subband constraint for the BWP switch 230. For example, the indication may include a constraint that the BWP 220 selected for the BWP switch 230 be in a different subband than the BWP 220 in which a consistent uplink LBT failure was identified. For example, after identifying a consistent uplink LBT failure in a first BWP 220-a that is part of a first subband, the UE 115-a may select a BWP 220 for the BWP switch 230 that is in a different subband than the first subband of which the first BWP 220-a is part. In some cases, the subband constraint may indicate that the UE 115-a starts from the subband farthest away from the first subband (e.g., the UE 115-a may select the fifth BWP 220-e for the first BWP switch 230-a based on the fifth BWP 220-e being in the subband farthest away from the subband of the first BWP 220-a). Furthermore, either the entire BWP 220 used for the BWP switch 230 or a subset of the BWPs 220 used for the BWP switch 230 may be in a different subband than the subband of the first BWP 220-a in which the consistent uplink BWP failure occurred.

[0088]

[0098] Additionally or alternatively, switching parameters 215 may include a configuration of whether BWPs 220 or a particular BWP 220 can be switched multiple times (e.g., an indication that switching to the same BWP 220 multiple times is permitted). For example, after performing a first BWP switch 230-a, UE 115-a may attempt to access the first BWP 220-a again during a subsequent BWP switch (e.g., second BWP switch 230-b, third BWP switch 230-c, etc.) based on the indication that the first BWP 220-a can be switched multiple times. Additionally or alternatively, UE 115-a may refrain from switching to a BWP 220 that was already previously switched to or monitored based on this indication. In some cases, switching parameters 215 may further include a configuration of a maximum time (e.g., a time threshold) between switches to the same BWP. For example, UE 115-a may select BWP 220 for BWP switch 230 based on the time between successive switches to BWP 220 satisfying a time threshold. That is, the time threshold may represent the amount of time UE 115-a must wait before attempting to switch to the same BWP 220 again after a previous attempt to switch to the same BWP 220 was unsuccessful.

[0089]

[0099] As shown, after performing a BWP switch 230, the UE 115-a may perform an LBT 225 for the selected (e.g., switched to) BWP 220 to determine whether the selected BWP 220 is available for subsequent communication with the base station 105-a. If the LBT 225 is unsuccessful for the selected BWP 220, the UE 115-a may perform a subsequent BWP switch 230 (e.g., based on the number of BWP switches 230 included in the switch parameters 215 or determined by the UE 115-a). In addition to or instead of performing an LBT 225 for the selected BWP 220, the UE 115-a may attempt to access the selected BWP 220 for communication with the base station 105-a (e.g., via a random access or RACH procedure).

[0090]

[0100] 3 illustrates an example of a wireless communication system 300 supporting uplink LBT failure recovery according to aspects of the present disclosure. In some examples, the wireless communication system 300 may implement aspects of the wireless communication system 100 and BWP switching configuration 200. For example, the wireless communication system 300 may include a base station 105-b and a UE 115-b, which may be examples of the corresponding base station 105 and UE 115, respectively, described with reference to FIGS. 1 and 2. In some cases, the base station 105-b and the UE 115-b may communicate over resources of a carrier 305. Furthermore, the carrier 305 may include resources in an unlicensed band (e.g., NR-U communication), which may be divided into one or more BWPs as described with reference to FIGS. 1 and 2.

[0091]

[0101] 2, the base station 105-b may transmit switching parameters 310 to the UE 115-b for the UE 115-b to determine and select a BWP to switch to based on identifying consistent uplink LBT failures on the first BWP. For example, the UE 115-b may perform one or more LBT procedures 315 for the first BWP and determine that the first BWP is unavailable based on the identified consistent uplink LBT failures (e.g., the number of failures associated with the set of LBT procedures 315 for the first BWP meets a threshold). Accordingly, the UE 115-b may then perform one or more BWP switches 320 based on the information in the switching parameters 310 to select a new BWP (e.g., a switched-to BWP) to attempt to connect with the base station 105-b.

[0092]

[0102] In some cases, if the failed BWP is within or on a PCell or PSCell (e.g., in a dual connectivity or carrier aggregation configuration), the UE 115-b may perform a RACH procedure 325 (e.g., a random access procedure) for a new BWP. For example, the RACH procedure 325 may include the UE 115-b transmitting a RACH preamble (e.g., message 1 (Msg1) in a four-step RACH or random access procedure) to the base station 105-b. In some cases, the RACH preamble may be randomly selected from a set of 64 predetermined sequences. This random selection may allow the base station 105-b to distinguish between multiple UEs 115 attempting to simultaneously access the system. The base station 105-b may respond with a random access response (RAR) (e.g., a second message (Msg2)) providing an uplink resource grant, a timing advance, and a temporary cell radio network temporary identifier (C-RNTI). The UE 115-b may then send an RRC connection request (e.g., a third message (Msg3)) along with a Temporary Mobile Subscriber Identity (TMSI) or a random identifier (if the UE 115 was previously connected to the same wireless network). The RRC connection request may also indicate the reason the UE 115-b is connecting to the network (e.g., an emergency, signaling, data exchange, etc.). The base station 105-b may respond to the connection request with a contention resolution message (e.g., a fourth message (Msg4)) addressed to the UE 115-b, which may provide a new C-RNTI. If the UE 115-b receives the contention resolution message with the correct identification information, the UE 115-b may proceed with RRC setup. If the UE 115-b does not receive the contention resolution message (e.g., there is a conflict with another UE 115), the UE 115-b may repeat the RACH procedure by sending a new RACH preamble (e.g., on a different BWP).Such an exchange of messages between the UE 115-b and the base station 105-b for random access may be referred to as a four-step random access procedure or a four-step RACH procedure.

[0093]

[0103] In other examples, a two-step random access procedure or a two-step RACH procedure may be implemented for random access. For example, a wireless device operating in a licensed or unlicensed spectrum within the wireless communication system 300 may initiate a two-step RACH procedure to reduce delay in establishing communication with the base station 105-b (e.g., compared to a four-step RACH procedure). In some cases, the two-step RACH procedure may operate regardless of whether the wireless device (e.g., the UE 115-b) has a valid timing advance (TA). For example, the UE 115-b may use a valid TA to coordinate the timing of its transmissions to the base station 105-b (e.g., to account for propagation delay) and may receive a valid TA as part of the two-step RACH procedure. Furthermore, the two-step RACH procedure may be applicable to any cell size, may work regardless of whether the RACH procedure is contention-based or contention-free, and may combine multiple RACH messages from a four-step RACH procedure. For example, a two-step RACH procedure may include a first message (e.g., Message A (MsgA)) that combines Msg1 and Msg3 of the four-step RACH procedure, and a second message (e.g., Message B (MsgB), successful RAR, etc.) that combines Msg2 and Msg4 of the four-step RACH procedure.

[0094]

[0104] However, in some cases, if a maximum number of Msg1 or MsgA attempts (e.g., a threshold number of attempts to transmit the first message) results in a RACH failure when UE 115-b attempts to perform BWP switch 320, UE 115-b may declare an RLF, or UE 115-b may switch to another BWP. Additionally or alternatively, if a consistent uplink LBT failure is identified before the RACH failure, UE 115-b may switch to another BWP and abort the RACH procedure.

[0095] Additionally or alternatively, the UE 115-b may send an LBT failure indication 330 to the base station 105-b to indicate a consistent LBT uplink failure on a BWP. For example, when a consistent uplink LBT failure occurs in a PSCell, the LBT failure indication 330 may include a dedicated cause value for this event (e.g., consistent uplink LBT failure) in the SCG failure message (e.g., rather than an indication of a RACH failure). In some cases, the dedicated cause value may include the number of switched BWPs used by the UE 115-b. Additionally or alternatively, when a consistent uplink LBT failure occurs in a BWP within an SCell, the LBT failure indication 330 may include a MAC CE for this indication on the PCell or another SCell. In some cases, if multiple active BWPs are in the SCell where the consistent uplink LBT failure occurs, the LBT failure indication 330 may include an indication on a different BWP in this SCell in a different subband. Additionally or alternatively, when a consistent uplink LBT failure occurs on a PCell (e.g., after all BWP switches and attempts to these) in the case of a dual connectivity configuration (e.g., or carrier aggregation configuration), the UE 115-b may perform MCG recovery through the SN (e.g., the secondary base station 105), and the LBT failure indication 330 may include an indication of the consistent uplink LBT failure that the UE 115-b sends to the SN, which then forwards the LBT failure indication 330 to the base station 105-b (e.g., the MN).

[0096] 4 illustrates an example process flow 400 for supporting uplink LBT failure recovery in accordance with aspects of the present disclosure. In some examples, process flow 400 may implement aspects of wireless communication system 100, BWP switching configuration 200, and wireless communication system 300. For example, process flow 400 may include base station 105-c and UE 115-c, which may be examples of corresponding base station 105 and UE 115, respectively, described with reference to FIGS. 1-3.

[0097]

[0105] In the following description of process flow 400, operations between UE 115-c and base station 105-c may be performed in a different order or at different times. Some operations may also be omitted from process flow 400, or other operations may be added to process flow 400. Although UE 115-c and base station 105-c are shown performing some operations of process flow 400, it should be understood that any wireless device may perform the operations shown.

[0098]

[0106] At 405, the UE 115-c may receive from the base station 105-c a BWP switch configuration message including switching parameters. In some cases, the switching parameters may include a number of BWP switches, an indication of which BWP may be switched to after the failure of another BWP, a priority order for multiple BWPs in the BWP switch configuration message, an indication to switch to a BWP in a different subband, an indication that the same BWP may be used multiple times for switching, a threshold time between switching to the same BWP, or a combination thereof. Additionally or alternatively, the switching parameters may include an indication of one or more of an upper threshold number of BWP switches, a lower threshold number of BWP switches, a fixed number of BWP switches, or a combination thereof.

[0099]

[0107] At 410, the UE 115-c may perform a set of LBT procedures for the first BWP.

[0100]

[0108] At 415, UE 115-c may select a second BWP based on the switching parameters. In some cases, the switching parameters may include an indication of a priority order of the BWPs, where selecting the second BWP is based on the priority order of the BWPs. Additionally or alternatively, the switching parameters may include an indication of a subband constraint for the second BWP, where selecting the second BWP is based on the subband constraint. In some cases, the second BWP may be entirely in a second subband that is different from the first subband of the first BWP, a subset of the second BWP may be in a second subband that is different from the first subband of the first BWP, or a combination thereof.

[0101]

[0109] In some cases, UE 115-c may determine the number of BWP switches based on a switching parameter, where switching to the second BWP is based on the number of BWP switches. Additionally or alternatively, the switching parameter may include an indication that switching to the same BWP multiple times is allowed (e.g., an indication that the same BWP may be used multiple times for switching), where selecting the second BWP is based on the indication. In some cases, UE 115-c may determine a time threshold for switching to the same BWP, where selecting the second BWP is based on the time between successive switches to the second BWP satisfying the time threshold.

[0102]

[0110] At 420, the UE 115-c may switch to the second BWP for uplink communication with the base station 105-c based on the switching parameters and the number of failures associated with the set of LBT procedures for the first BWP. In some cases, the UE 115-c may determine to switch to the second BWP based on the number of failures associated with the set of LBT procedures for the first BWP satisfying a threshold.

[0103]

[0111] Further, in some cases, UE 115-c may perform one or more LBT procedures for the second BWP and may switch to a third BWP in accordance with the BWP switching configuration and switching parameters based on the number of failures associated with the one or more LBT procedures for the second BWP (e.g., meeting a threshold).

[0104]

[0112] At 425, UE 115-c may perform a random access procedure (e.g., a RACH procedure) for the second BWP based on switching to the second BWP. For example, UE 115-c may transmit a first message (e.g., Msg1, MsgA, etc.) of the random access procedure. In some cases, UE 115-c may determine that a threshold number of attempts to transmit the first message has been met and may declare an RLF based on the threshold number of attempts to transmit the first message being met, or may switch to a third BWP, or a combination thereof. Additionally or alternatively, UE 115-c may determine that the number of uplink LBT failures for the second BWP exceeds a threshold, and may switch to the third BWP based on the number of uplink LBT failures for the second BWP exceeding the threshold and abort the random access procedure for the second BWP.

[0105]

[0113] At 430, the UE 115-c may determine that the number of uplink LBT failures for the first BWP occurs on the PSCell and may transmit a dedicated reason value for the number of uplink LBT failures for the first BWP in the SCG failure message. In some cases, the dedicated reason value may include the number of attempted switched BWPs. Additionally or alternatively, the UE 115-c may determine that the number of uplink LBT failures for the first BWP occurs on the SCell and may transmit a MAC CE indicating the uplink LBT failure on the PCell or an additional SCell. In some cases, the UE 115-c may determine that the SCell includes a set of BWPs that includes the first BWP and may transmit a MAC CE on the additional BWP in a subband for a different SCell than the first BWP.

[0106]

[0114] Additionally or alternatively, the UE 115-c may perform an MCG recovery procedure via the SN based on determining that the number of uplink LBT failures for the second BWP meets a threshold and that the number of uplink LBT failures for the second BWP occurs on the PCell. In some cases, the UE 115-c may send an indication of failure for the PCell to the SN based on the number of uplink LBT failures for the second BWP exceeding a threshold.

[0107]

[0115] At 435, the base station 105-c may receive the first uplink transmission in the first BWP from the UE 115-c. Additionally or alternatively, the base station 105-c may receive the uplink transmission in the second BWP from the UE 115-c based on the switching parameters and the uplink LBT failure.

[0108]

[0116] 5 shows a block diagram 500 of a device 505 supporting uplink LBT failure recovery according to an aspect of the present disclosure. The device 505 may be an example of an aspect of a UE 115 described herein. The device 505 may include a receiver 510, a UE communications manager 515, and a transmitter 520. The device 505 may also include a processor. Each of these components may be in communication with each other (e.g., via one or more buses).

[0109]

[0117] The receiver 510 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to uplink LBT failure recovery, etc.). The information may be passed to other components of the device 505. The receiver 510 may be an example of an aspect of the transceiver 820 described with reference to FIG. 8. The receiver 510 may utilize a single antenna or a set of antennas.

[0110]

[0118] The UE communications manager 515 may receive a BWP switch configuration message from the base station, the BWP switch configuration message including the switch parameters. Additionally, the UE communications manager 515 may implement a set of LBT procedures for the first BWP. In some cases, the UE communications manager 515 may switch to a second BWP for uplink communications with the base station based on the switch parameters and the number of failures associated with the set of LBT procedures for the first BWP. The UE communications manager 515 may be an example of an aspect of the UE communications manager 810 described herein.

[0111]

[0119] Based on actions performed by the UE communications manager 515, the UE 115 may efficiently identify a BWP to switch to when a first BWP generates a consistent uplink BWP failure. Thus, the UE 115 may save power by not having to attempt to use a non-ideal BWP to switch to. Furthermore, the UE 115 may reduce latency associated with attempting and failing other non-ideal BWPs to switch to.

[0112]

[0120] The UE communications manager 515, or any subcomponents thereof, may be implemented in hardware, in code executed by a processor (e.g., software or firmware), or any combination thereof. If implemented in code executed by a processor, the functions of the UE communications manager 515, or any subcomponents thereof, may be performed by a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in this disclosure.

[0113]

[0121] The UE communications manager 515 or subcomponents thereof may be physically located in various locations, including being distributed such that portions of the functionality are implemented at different physical locations by one or more physical components. In some examples, the UE communications manager 515 or subcomponents thereof may be separate and distinct components according to various aspects of the present disclosure. In some examples, the UE communications manager 515 or subcomponents thereof may be combined with one or more other hardware components, including, but not limited to, an input / output (I / O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof according to various aspects of the present disclosure.

[0114]

[0122] The transmitter 520 may transmit signals generated by other components of the device 505. In some examples, the transmitter 520 may be co-located with the receiver 510 in a transceiver module. For example, the transmitter 520 may be an example of an aspect of the transceiver 820 described with reference to FIG. 8. The transmitter 520 may utilize a single antenna or a set of antennas.

[0115]

[0123] 6 shows a block diagram 600 of a device 605 supporting uplink LBT failure recovery according to an aspect of the present disclosure. The device 605 may be an example of an aspect of the device 505 or UE 115 described herein. The device 605 may include a receiver 610, a UE communications manager 615, and a transmitter 635. The device 605 may also include a processor. Each of these components may be in communication with each other (e.g., via one or more buses).

[0116]

[0124] The receiver 610 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to uplink LBT failure recovery, etc.). The information may be passed to other components of the device 605. The receiver 610 may be an example of an aspect of the transceiver 820 described with reference to FIG. 8. The receiver 610 may use a single antenna or a set of antennas.

[0117]

[0125] The UE communications manager 615 may be an example of an aspect of the UE communications manager 515 described herein. The UE communications manager 615 may include a switching parameter receiver 620, an LBT procedure component 625, and a BWP switching component 630. The UE communications manager 615 may be an example of an aspect of the UE communications manager 810 described herein.

[0118]

[0126] The switching parameter receiver 620 may receive a BWP switching configuration message from a base station that includes switching parameters.

[0119]

[0127] The LBT procedure component 625 may implement a set of LBT procedures for the first BWP.

[0120]

[0128] The BWP switching component 630 may switch to the second BWP for uplink communication with the base station based on the switching parameters and the number of failures associated with the set of LBT procedures for the first BWP.

[0121]

[0129] Based on receiving the switching parameters, a processor of the UE 115 (e.g., controlling the receiver 610, the transmitter 635, or the transceiver 820 described with reference to FIG. 8) may identify a BWP that has a higher likelihood of successfully switching after identifying a consistent uplink LBT failure in the first BWP. Thus, the processor may have reduced computational complexity because the information included in the switching parameters is used to identify and select a BWP to switch to rather than having to solely determine which BWP to switch to.

[0122]

[0130] The transmitter 635 may transmit signals generated by other components of the device 605. In some examples, the transmitter 635 may be co-located with the receiver 610 in a transceiver module. For example, the transmitter 635 may be an example of an aspect of the transceiver 820 described with reference to FIG. 8. The transmitter 635 may utilize a single antenna or a set of antennas.

[0123]

[0131] 7 shows a block diagram 700 of a UE communications manager 705 supporting uplink LBT failure recovery according to an aspect of the present disclosure. The communications manager 705 may be an example of an aspect of the UE communications manager 515, 615, or 810 described herein. The UE communications manager 705 may include a switching parameter receiver 710, an LBT procedure component 715, a BWP switching component 720, a BWP selector 725, a RACH component 730, a dedicated cause value transmitter 735, a MAC CE transmitter 740, and a consistent LBT failure determination component 745. Each of these modules may communicate with one another directly or indirectly (e.g., via one or more buses).

[0124]

[0132] The switching parameter receiver 710 may receive a BWP switching configuration message from the base station, the BWP switching configuration message including the switching parameters. In some examples, the switching parameter receiver 710 may determine the number of BWP switches based on the switching parameters, where switching to the second BWP is based on the number of BWP switches. In some cases, the number of BWP switches may include an upper threshold number of BWP switches, a lower threshold number of BWP switches, a fixed number of BWP switches, or a combination thereof.

[0125]

[0133] The LBT procedures component 715 may implement a set of LBT procedures for the first BWP.

[0126]

[0134] The BWP switching component 720 may switch to a second BWP for uplink communication with the base station based on switching parameters and the number of failures associated with the set of LBT procedures for the first BWP. In some examples, the BWP switching component 720 may implement one or more LBT procedures for the second BWP and switch to a third BWP in accordance with the BWP switching configuration and switching parameters based on the number of failures associated with the one or more LBT procedures for the second BWP.

[0127]

[0135] The BWP selector 725 may select the second BWP based on the switching parameters. In some cases, the switching parameters may include an indication of a priority order of the BWPs, where selecting the second BWP is based on the priority order of the BWPs. Additionally or alternatively, the switching parameters may include an indication of a subband constraint for the second BWP, where selecting the second BWP is based on the subband constraint. In some cases, the second BWP may be entirely in a second subband different from the first subband of the first BWP, a subset of the second BWP may be in a second subband different from the first subband of the first BWP, or a combination thereof. Additionally or alternatively, the switching parameters may include an indication that switching to the same BWP multiple times is allowed, where selecting the second BWP is based on the indication. Thus, the BWP selector 725 may determine a time threshold for switching to the same BWP, where selecting a second BWP is based on the time between successive switches to the second BWP satisfying the time threshold.

[0128]

[0136] The RACH component 730 may perform a random access procedure for the second BWP based on switching to the second BWP. In some examples, the RACH component 730 may transmit a first message of the random access procedure, determine that a threshold number of attempts to transmit the first message has been met, declare an RLF based on the threshold number of attempts to transmit the first message being met, switch to a third BWP, or perform a combination thereof. Additionally or alternatively, the RACH component 730 may determine that the number of uplink LBT failures for the second BWP exceeds a threshold, switch to the third BWP based on the number of uplink LBT failures for the second BWP exceeding the threshold, and abort the random access procedure for the second BWP.

[0129]

[0137] The dedicated cause value transmitter 735 may determine that an uplink LBT failure for the first BWP of the number occurs on the PCell. Accordingly, the dedicated cause value transmitter 735 may transmit a dedicated cause value for the number of uplink LBT failures for the first BWP in the SCG failure message. In some cases, the dedicated cause value may include the number of switched BWPs attempted.

[0130]

[0138] The MAC CE transmitter 740 may determine that an uplink LBT failure for the first BWP of the number occurs on the SCell and may transmit a MAC CE indicating the uplink LBT failure on the PCell or the additional SCell. In some examples, the MAC CE transmitter 740 may determine that the SCell includes a set of BWPs that includes the first BWP and may transmit a MAC CE on the additional BWP in a subband for a different SCell than the first BWP.

[0131]

[0139] The consistent LBT failure determination component 745 may determine to switch to the second BWP based on the number of failures associated with the set of LBT procedures for the first BWP meeting a threshold. In some examples, the consistent LBT failure determination component 745 may perform an MCG recovery procedure via the SN based on determining that the number of uplink LBT failures for the second BWP meets a threshold and that uplink LBT failures for that number of second BWPs occur on the PCell. Further, the consistent LBT failure determination component 745 may send an indication of failure for the PCell to the SN based on the number of uplink LBT failures for the second BWP exceeding a threshold.

[0132]

[0140] 8 shows a diagram of a system 800 including a device 805 supporting uplink LBT failure recovery according to an aspect of the present disclosure. The device 805 may be an example of or may include components of the device 505, device 605, or UE 115 described herein. The device 805 may include components for two-way voice and data communication, including components for transmitting and receiving communications, including a UE communications manager 810, an I / O controller 815, a transceiver 820, an antenna 825, a memory 830, and a processor 840. These components may be in electronic communication via one or more buses (e.g., bus 845).

[0133]

[0141] The UE communications manager 810 may receive a BWP switch configuration message from the base station, the BWP switch configuration message including the switch parameters. Additionally, the UE communications manager 810 may implement a set of LBT procedures for the first BWP. In some cases, the UE communications manager 810 may switch to a second BWP for uplink communications with the base station based on the switch parameters and the number of failures associated with the set of LBT procedures for the first BWP.

[0134]

[0142] The I / O controller 815 may manage input and output signals for the device 805. The I / O controller 815 may also manage peripherals not built into the device 805. In some cases, the I / O controller 815 may represent a physical connection or port to an external peripheral. In some cases, the I / O controller 815 may utilize an operating system such as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS / 2®, UNIX®, LINUX®, or another known operating system. In other cases, the I / O controller 815 may represent or interact with a modem, keyboard, mouse, touchscreen, or similar device. In some cases, the I / O controller 815 may be implemented as part of the processor. In some cases, a user may interact with the device 805 through the I / O controller 815 or through hardware components controlled by the I / O controller 815.

[0135]

[0143] The transceiver 820 may communicate bidirectionally via one or more antennas, wired links, or wireless links as described herein. For example, the transceiver 820 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. The transceiver 820 may also include a modem for modulating packets and providing the modulated packets to an antenna for transmission, and for demodulating packets received from the antenna.

[0136]

[0144] In some cases, a wireless device may include a single antenna 825. However, in some cases, the device may have two or more antennas 825 that may be capable of simultaneously transmitting or receiving multiple wireless transmissions.

[0137]

[0145] The memory 830 may include random access memory (RAM) and read-only memory (ROM). The memory 830 may store computer-readable computer-executable code 835, which includes instructions that, when executed, cause the processor to perform various functions described herein. In some cases, the memory 830 may include a basic I / O system (BIOS), which may control basic hardware or software operations, such as interaction with peripheral components or devices, among other things.

[0138]

[0146] Processor 840 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a central processing unit (CPU), a microcontroller, an ASIC, an FPGA, a programmable logic device, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some cases, processor 840 may be configured to operate a memory array using a memory controller. In other cases, the memory controller may be incorporated into processor 840. Processor 840 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 830) to cause device 805 to perform various functions (e.g., functions or tasks supporting uplink LBT failure recovery).

[0139]

[0147] The code 835 may include instructions for implementing aspects of the present disclosure, including instructions for supporting wireless communication. The code 835 may be stored in a non-transitory computer-readable medium, such as system memory or other type of memory. In some cases, the code 835 may not be directly executable by the processor 840, but may (e.g., when compiled and executed) cause a computer to perform functions described herein.

[0140]

[0148] 9 shows a block diagram 900 of a device 905 supporting uplink LBT failure recovery according to an aspect of the present disclosure. The device 905 may be an example of an aspect of a base station 105 described herein. The device 905 may include a receiver 910, a base station communications manager 915, and a transmitter 920. The device 905 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0141]

[0149] The receiver 910 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to uplink LBT failure recovery, etc.). The information may be passed to other components of the device 905. The receiver 910 may be an example of an aspect of the transceiver 1220 described with reference to FIG. 12. The receiver 910 may utilize a single antenna or a set of antennas.

[0142]

[0150] The base station communications manager 915 may send a BWP switch configuration message to the UE, including the switch parameters. In some cases, the base station communications manager 915 may receive a first uplink transmission in the first BWP from the UE. Additionally, the base station communications manager 915 may receive an uplink transmission in a second BWP from the UE based on the switch parameters and the uplink LBT failure. The base station communications manager 915 may be an example of an aspect of the base station communications manager 1210 described herein.

[0143]

[0151] The base station communications manager 915, or subcomponents thereof, may be implemented in hardware, code executed by a processor (e.g., software or firmware), or any combination thereof. If implemented in code executed by a processor, the functions of the base station communications manager 915, or subcomponents thereof, may be performed by a general-purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in this disclosure.

[0144]

[0152] The base station communications manager 915, or subcomponents thereof, may be physically located in various locations, including being distributed such that portions of its functionality are implemented at different physical locations by one or more physical components. In some examples, the base station communications manager 915, or subcomponents thereof, may be separate and distinct components according to various aspects of the present disclosure. In some examples, the base station communications manager 915, or subcomponents thereof, may be combined with one or more other hardware components, including, but not limited to, an I / O component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof, according to various aspects of the present disclosure.

[0145]

[0153] The transmitter 920 may transmit signals generated by other components of the device 905. In some cases, the transmitter 920 may be co-located with the receiver 910 in a transceiver module. For example, the transmitter 920 may be an example of an aspect of the transceiver 1220 described with reference to FIG. 12. The transmitter 920 may utilize a single antenna or a set of antennas.

[0146]

[0154] 10 shows a block diagram 1000 of a device 1005 supporting uplink LBT failure recovery according to an aspect of the present disclosure. The device 1005 may be an example of an aspect of the device 905 or base station 105 described herein. The device 1005 may include a receiver 1010, a base station communications manager 1015, and a transmitter 1035. The device 1005 may also include a processor. Each of these components may be in communication with each other (e.g., via one or more buses).

[0147]

[0155] The receiver 1010 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to uplink LBT failure recovery, etc.). The information may be passed to other components of the device 1005. The receiver 1010 may be an example of an aspect of the transceiver 1220 described with reference to FIG. 12. The receiver 1010 may utilize a single antenna or a set of antennas.

[0148]

[0156] The base station communications manager 1015 may be an example of an aspect of the base station communications manager 915 described herein. The base station communications manager 1015 may include a switching parameter transmitter 1020, a first BWP receiver 1025, and a switched BWP receiver 1030. The base station communications manager 1015 may be an example of an aspect of the base station communications manager 1210 described herein.

[0149]

[0157] The switching parameter transmitter 1020 may send a BWP Switch Configuration message including the switching parameters to the UE.

[0150]

[0158] The first BWP receiver 1025 may receive a first uplink transmission in the first BWP from the UE.

[0151]

[0159] The switched BWP receiver 1030 may receive an uplink transmission in the second BWP from the UE based on the switching parameters and the uplink LBT failure.

[0152]

[0160] The transmitter 1035 may transmit signals generated by other components of the device 1005. In some examples, the transmitter 1035 may be co-located with the receiver 1010 in a transceiver module. For example, the transmitter 1035 may be an example of an aspect of the transceiver 1220 described with reference to FIG. 12. The transmitter 1035 may utilize a single antenna or a set of antennas.

[0153]

[0161] 11 shows a block diagram 1100 of a base station communications manager 1105 supporting uplink LBT failure recovery according to an aspect of the present disclosure. The base station communications manager 1105 may be an example of an aspect of the base station communications manager 915, the base station communications manager 1015, or the base station communications manager 1210 described herein. The base station communications manager 1105 may include a switching parameter transmitter 1110, a first BWP receiver 1115, a switched BWP receiver 1120, and an LBT failure indication receiver 1125. Each of these modules may communicate with each other directly or indirectly (e.g., via one or more buses).

[0154]

[0162] The switching parameter transmitter 1110 may transmit a BWP switch configuration message including switching parameters to the UE. In some cases, the switching parameters may include a number of BWP switches, an indication of which BWP can be switched to after a failure of another BWP, a priority order for the set of BWPs in the BWP switch configuration message, an indication to switch to a BWP in a different subband, an indication that the same BWP can be used multiple times for switching, a threshold time between switching to the same BWP, or a combination thereof.

[0155]

[0163] The first BWP receiver 1115 may receive a first uplink transmission in the first BWP from the UE.

[0156]

[0164] The switched BWP receiver 1120 may receive an uplink transmission in the second BWP from the UE based on the switching parameters and the uplink LBT failure.

[0157]

[0165] The LBT failure indication receiver 1125 may receive from the UE a dedicated reason value for the number of uplink LBT failures for the first BWP in an SCG failure message, where the dedicated reason value includes the number of attempted switched BWPs. Additionally or alternatively, the LBT failure indication receiver 1125 may receive from the UE a MAC CE indicating the number of uplink LBT failures for the first BWP on the PCell or SCell. Additionally or alternatively, the LBT failure indication receiver 1125 may receive from the SN an indication of failure for the PCell based on the number of uplink LBT failures for the first BWP exceeding a threshold. In some cases, the MAC CE may be received on an additional BWP in a subband for a secondary cell different from the first BWP.

[0158]

[0166] 12 shows a diagram of a system 1200 including a device 1205 supporting uplink LBT failure recovery according to an aspect of the present disclosure. The device 1205 may be an example of, or may include, the components of, the device 905, the device 1005, or the base station 105 described herein. The device 1205 may include components for two-way voice and data communication, including components for transmitting and receiving communications, including a base station communications manager 1210, a network communications manager 1215, a transceiver 1220, an antenna 1225, a memory 1230, a processor 1240, and an inter-station communications manager 1245. These components may be in electronic communication via one or more buses (e.g., bus 1250).

[0159]

[0167] The base station communications manager 1210 may send a BWP switch configuration message including the switch parameters to the UE. In some cases, the base station communications manager 1210 may receive a first uplink transmission in the first BWP from the UE. Additionally, the base station communications manager 1210 may receive an uplink transmission in a second BWP from the UE based on the switch parameters and the uplink LBT failure.

[0160]

[0168] The network communications manager 1215 may manage communications with the core network (e.g., via one or more wired backhaul links). For example, the network communications manager 1215 may manage the forwarding of data communications for client devices, such as one or more UEs 115.

[0161]

[0169] The transceiver 1220 may communicate bidirectionally via one or more antennas, wired links, or wireless links as described herein. For example, the transceiver 1220 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. The transceiver 1220 may also include a modem for modulating packets and providing the modulated packets to an antenna for transmission, and for demodulating packets received from the antenna.

[0162]

[0170] In some cases, a wireless device may include a single antenna 1225. However, in some cases, the device may have two or more antennas 1225 that may be capable of simultaneously transmitting or receiving multiple wireless transmissions.

[0163]

[0171] The memory 1230 may include RAM, ROM, or a combination thereof. The memory 1230 may store computer-readable code 1235 including instructions that, when executed by a processor (e.g., processor 1240), cause the device to perform various functions described herein. In some cases, the memory 1230 may include a BIOS, which may control basic hardware or software operations, such as interaction with peripheral components or devices, among other things.

[0164]

[0172] Processor 1240 may include intelligent hardware devices (e.g., general-purpose processors, DSPs, CPUs, microcontrollers, ASICs, FPGAs, programmable logic devices, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some cases, processor 1240 may be configured to operate a memory array using a memory controller. In some cases, the memory controller may be incorporated into processor 1240. Processor 1240 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 1230) to cause device 1205 to perform various functions (e.g., functions or tasks supporting uplink LBT failure recovery).

[0165]

[0173] The inter-station communications manager 1245 may manage communications with other base stations 105 and may include a controller or scheduler for controlling communications with the UE 115 in cooperation with the other base stations 105. For example, the inter-station communications manager 1245 may coordinate scheduling for transmissions to the UE 115 for various interference mitigation techniques, such as beamforming or joint transmission. In some examples, the inter-station communications manager 1245 may provide an X2 interface within the LTE / LTE-A wireless communications network technology for communicating between the base stations 105.

[0166]

[0174] Code 1235 may include instructions for implementing aspects of the present disclosure, including instructions for supporting wireless communication. Code 1235 may be stored in a non-transitory computer-readable medium, such as system memory or other type of memory. In some cases, code 1235 may not be directly executable by processor 1240, but may (e.g., when compiled and executed) cause a computer to perform functions described herein.

[0167]

[0175] FIG. 13 shows a flowchart illustrating a method 1300 for supporting uplink LBT failure recovery according to an aspect of the present disclosure. The operations of method 1300 may be implemented by the UE 115 or components thereof described herein. For example, the operations of method 1300 may be performed by the UE communications manager described with reference to FIGS. 5-8. In some examples, the UE may execute a set of instructions to control functional elements of the UE to perform the described functionality. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the described functionality.

[0168]

[0176] At 1305, the UE may receive a BWP Switch Configuration message from the base station, the BWP Switch Configuration message including the switching parameters. The operations of 1305 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1305 may be performed by a switching parameter receiver described with reference to FIGS. 5-8.

[0169]

[0177] At 1310, the UE may perform a set of LBT procedures for the first BWP. The operations of 1310 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1310 may be performed by LBT procedure components described with reference to FIGS. 5-8.

[0170]

[0178] At 1315, the UE may switch to the second BWP for uplink communication with the base station based on the switching parameters and the number of failures associated with the set of LBT procedures for the first BWP. The operations of 1315 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1315 may be performed by a BWP switching component described with reference to FIGS. 5-8.

[0171]

[0179] FIG. 14 shows a flowchart illustrating a method 1400 for supporting uplink LBT failure recovery according to an aspect of the present disclosure. The operations of method 1400 may be implemented by the UE 115 or components thereof described herein. For example, the operations of method 1400 may be performed by the UE communications manager described with reference to FIGS. 5-8. In some examples, the UE may execute a set of instructions to control functional elements of the UE to perform the described functionality. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the described functionality.

[0172]

[0180] At 1405, the UE may receive a BWP Switch Configuration message from the base station, the BWP Switch Configuration message including the switching parameters. The operations of 1405 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1405 may be performed by a switching parameter receiver described with reference to FIGS. 5-8.

[0173]

[0181] At 1410, the UE may perform a set of LBT procedures for the first BWP. The operations of 1410 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1410 may be performed by LBT procedure components described with reference to FIGS. 5-8.

[0174]

[0182] At 1415, the UE may determine a number of BWP switches based on the switching parameters, where switching to the second BWP is based on the number of BWP switches. The operations of 1415 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1415 may be performed by a switching parameter receiver described with reference to FIGS. 5-8.

[0175]

[0183] At 1420, the UE may switch to a second BWP for uplink communication with the base station based on the switching parameters and the number of failures associated with the set of LBT procedures for the first BWP. The operations of 1420 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1420 may be performed by a BWP switching component described with reference to FIGS. 5-8.

[0176]

[0184] FIG. 15 shows a flowchart illustrating a method 1500 for supporting uplink LBT failure recovery according to an aspect of the present disclosure. The operations of method 1500 may be implemented by the UE 115 or components thereof described herein. For example, the operations of method 1500 may be performed by the UE communications manager described with reference to FIGS. 5-8. In some examples, the UE may execute a set of instructions to control functional elements of the UE to perform the described functionality. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the described functionality.

[0177]

[0185] At 1505, the UE may receive a BWP Switch Configuration message from the base station, the BWP Switch Configuration message including the switching parameters. The operations of 1505 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1505 may be performed by a switching parameter receiver described with reference to FIGS. 5-8.

[0178]

[0186] At 1510, the UE may perform a set of LBT procedures for the first BWP. The operations of 1510 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1510 may be performed by LBT procedure components described with reference to FIGS. 5-8.

[0179]

[0187] At 1515, the UE may select a second BWP based on the switching parameters. The operations of 1515 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1515 may be performed by a BWP selector described with reference to FIGS. 5-8.

[0180]

[0188] At 1520, the UE may switch to the second BWP for uplink communication with the base station based on the switching parameters and the number of failures associated with the set of LBT procedures for the first BWP. The operations of 1520 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1520 may be performed by a BWP switching component described with reference to FIGS. 5-8.

[0181]

[0189] FIG. 16 shows a flowchart illustrating a method 1600 for supporting uplink LBT failure recovery according to an aspect of the present disclosure. The operations of method 1600 may be implemented by the UE 115 or components thereof described herein. For example, the operations of method 1600 may be performed by the UE communications manager described with reference to FIGS. 5-8. In some examples, the UE may execute a set of instructions to control functional elements of the UE to perform the described functionality. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the described functionality.

[0182]

[0190] At 1605, the UE may receive a BWP Switch Configuration message from the base station, the BWP Switch Configuration message including the switching parameters. The operations of 1605 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1605 may be performed by a switching parameter receiver described with reference to FIGS. 5-8.

[0183]

[0191] At 1610, the UE may perform a set of LBT procedures for the first BWP. The operations of 1610 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1610 may be performed by LBT procedure components described with reference to FIGS. 5-8.

[0184]

[0192] At 1615, the UE may switch to the second BWP for uplink communication with the base station based on the switching parameters and the number of failures associated with the set of LBT procedures for the first BWP. The operations of 1615 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1615 may be performed by a BWP switching component described with reference to FIGS. 5-8.

[0185]

[0193] At 1620, the UE may perform a random access procedure for the second BWP based on the RACH component 730 switching to the second BWP. The operation of 1620 may be performed according to methods described herein. In some examples, aspects of the operation of 1620 may be performed by the RACH component described with reference to FIGS. 5-8.

[0186]

[0194] FIG. 17 shows a flowchart illustrating a method 1700 for supporting uplink LBT failure recovery according to an aspect of the present disclosure. The operations of method 1700 may be implemented by the UE 115 or components thereof described herein. For example, the operations of method 1700 may be performed by the UE communications manager described with reference to FIGS. 5-8. In some examples, the UE may execute a set of instructions to control functional elements of the UE to perform the described functionality. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the described functionality.

[0187]

[0195] At 1705, the UE may receive a BWP Switch Configuration message from the base station, the BWP Switch Configuration message including the switching parameters. The operations of 1705 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1705 may be performed by a switching parameter receiver described with reference to FIGS. 5-8.

[0188]

[0196] At 1710, the UE may perform a set of LBT procedures for the first BWP. The operations of 1710 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1710 may be performed by LBT procedure components described with reference to FIGS. 5-8.

[0189]

[0197] At 1715, the UE may determine to switch to the second BWP based on the number of failures associated with the set of LBT procedures for the first BWP satisfying a threshold. The operations of 1715 may be performed according to methods described herein. In some examples, aspects of the operations of 1715 may be performed by a consistent LBT failure determination component described with reference to FIGS. 5-8.

[0190]

[0198] At 1720, the UE may switch to a second BWP for uplink communication with the base station based on the switching parameters and the number of failures associated with the set of LBT procedures for the first BWP. The operations of 1720 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1720 may be performed by a BWP switching component described with reference to FIGS. 5-8.

[0191]

[0199] FIG. 18 shows a flowchart illustrating a method 1800 for supporting uplink LBT failure recovery according to an aspect of the present disclosure. The operations of method 1800 may be implemented by the base station 105 described herein or components thereof. For example, the operations of method 1800 may be performed by the base station communications manager described with reference to FIGS. 9-12. In some examples, the base station may execute a set of instructions to control functional elements of the base station to perform the described functionality. Additionally or alternatively, the base station may use dedicated hardware to perform aspects of the described functionality.

[0192]

[0200] At 1805, the base station may send a BWP Switch Configuration message including the switching parameters to the UE. The operations of 1805 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1805 may be performed by the switching parameter transmitter described with reference to FIGS. 9-12.

[0193]

[0201] At 1810, the base station may receive a first uplink transmission in a first BWP from the UE. The operations of 1810 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1810 may be performed by a first BWP receiver described with reference to FIGS. 9-12.

[0194]

[0202] At 1815, the base station may receive an uplink transmission in a second BWP from the UE based on the switching parameters and the uplink LBT failure. The operations of 1815 may be performed in accordance with methods described herein. In some examples, aspects of the operations of 1815 may be performed by a switched BWP receiver described with reference to FIGS. 9-12.

[0195]

[0203] It should be noted that the methods described herein represent possible implementations, and that acts and steps may be rearranged or possibly modified, and that other implementations are possible. Furthermore, aspects from two or more of the methods may be combined.

[0196]

[0204] The following provides a summary of aspects of the present disclosure.

[0197]

[0205] Aspect 1: A method for wireless communication in a UE, comprising: receiving a bandwidth portion switching configuration message from a base station, the bandwidth portion switching configuration message comprising switching parameters; performing multiple listen-before-talk procedures for a first bandwidth portion; and switching to a second bandwidth portion for uplink communication with the base station based at least in part on the switching parameters and a number of failures associated with the multiple listen-before-talk procedures for the first bandwidth portion.

[0198]

[0206] Aspect 2: The method of aspect 1, further comprising performing a random access procedure on the second bandwidth portion based at least in part on switching to the second bandwidth portion.

[0199]

[0207] Aspect 3: The method of aspect 2, further comprising: transmitting a first message of a random access procedure; determining that a threshold number of attempts to transmit the first message has been met; and declaring a radio link failure or switching to a third bandwidth portion, or a combination thereof, based at least in part on the threshold number of attempts to transmit the first message having been met.

[0200]

[0208] Aspect 4: The method of any of aspects 2 to 3, further comprising: determining that a number of uplink listen-before-talk failures for the second bandwidth portion exceeds a threshold; switching to a third bandwidth portion based at least in part on the number of uplink listen-before-talk failures for the second bandwidth portion exceeding the threshold; and aborting the random access procedure on the second bandwidth portion.

[0201]

[0209] Aspect 5: The method of any one of aspects 1 to 4, further comprising: determining that a number of uplink listen-before-talk failures for the first bandwidth portion occur in the primary-secondary cell; and transmitting a dedicated cause value for the number of uplink listen-before-talk failures for the first bandwidth portion in a secondary cell group failure message.

[0202]

[0210] Aspect 6: The method of aspect 5, wherein the dedicated reason value comprises a number of attempted switched bandwidth portions.

[0203]

[0211] Aspect 7: The method of any of aspects 1 to 6, further comprising: determining that an uplink listen-before-talk failure for a number of first bandwidth portions occurs in a secondary cell; and transmitting a medium access control (MAC) control element indicating the uplink listen-before-talk failure on the primary cell or an additional secondary cell.

[0204]

[0212] Aspect 8: The method of aspect 7, wherein transmitting the MAC control element comprises determining that the secondary cell comprises a plurality of bandwidth portions including the first bandwidth portion, and transmitting the MAC control element on an additional bandwidth portion in a subband for the secondary cell that is different from the first bandwidth portion.

[0205]

[0213] Aspect 9: The method of any of aspects 1 to 8, further comprising determining to switch to the second bandwidth portion based at least in part on a number of failures associated with multiple listen-before-talk procedures for the first bandwidth portion meeting a threshold.

[0206]

[0214] Aspect 10: The method of aspect 9, further comprising: implementing a master cell group recovery procedure via the secondary node based at least in part on determining that the number of uplink listen-before-talk failures for the second bandwidth portion meets a threshold and that the number of uplink listen-before-talk failures for the second bandwidth portion occur in the primary cell.

[0207]

[0215] Aspect 11: The method described in aspect 10, wherein performing a master cell group recovery procedure via the secondary node comprises sending to the secondary node an indication of failure for the primary cell based at least in part on the number of uplink listen-before-talk failures for the second bandwidth portion exceeding a threshold.

[0208]

[0216] Aspect 12: The method of any of aspects 1 to 11, further comprising determining a number of bandwidth portion switches based at least in part on the switching parameters, wherein the switching to the second bandwidth portion is based at least in part on the number of bandwidth portion switches.

[0209]

[0217] Aspect 13: The method of aspect 12, wherein the switching parameters comprise one or more indications of an upper threshold number of bandwidth portion switching, a lower threshold number of bandwidth portion switching, a fixed number of bandwidth portion switching, or a combination thereof.

[0210]

[0218] Aspect 14: The method of any of aspects 1 to 13, further comprising selecting the second bandwidth portion based at least in part on a switching parameter.

[0211]

[0219] Aspect 15: The method of aspect 14, wherein the switching parameters comprise an indication of a priority order of the bandwidth portions, and selecting the second bandwidth portion is based at least in part on the priority order of the bandwidth portions.

[0212]

[0220] Aspect 16: The method of any of aspects 14 to 15, wherein the switching parameters comprise an indication of a subband constraint for the second bandwidth portion, and selecting the second bandwidth portion is based at least in part on the subband constraint.

[0213]

[0221] Aspect 17: The method of aspect 16, wherein the second bandwidth portion is entirely in a second subband different from the first subband of the first bandwidth portion, a subset of the second bandwidth portion is in a second subband different from the first subband of the first bandwidth portion, or a combination thereof.

[0214]

[0222] Aspect 18: The method of any of aspects 14 to 17, wherein the switching parameters comprise an indication that switching to the same bandwidth portion multiple times is allowed, and selecting the second bandwidth portion is based at least in part on the indication.

[0215]

[0223] Aspect 19: The method of aspect 18, further comprising determining a time threshold for switching to the same bandwidth portion, wherein selecting the second bandwidth portion is based at least in part on the time between successive switches to the second bandwidth portion satisfying the time threshold.

[0216]

[0224] Aspect 20: A method according to any of aspects 1 to 19, further comprising: implementing one or more listen-before-talk procedures for the second bandwidth portion; and switching to the third bandwidth portion in accordance with the bandwidth portion switching configuration message and the switching parameters based at least in part on a number of failures associated with the one or more listen-before-talk procedures for the second bandwidth portion.

[0217]

[0225] Aspect 21: A method for wireless communication in a base station, comprising: transmitting a bandwidth portion switching configuration message to a UE, the bandwidth portion switching configuration message comprising switching parameters; receiving a first uplink transmission in the first bandwidth portion from the UE; and receiving an uplink transmission in the second bandwidth portion from the UE based at least in part on the switching parameters and an uplink listen-before-talk failure.

[0218]

[0226] Aspect 22: The method of aspect 21, further comprising receiving from the UE a dedicated reason value for the number of uplink listen-before-talk failures for the first bandwidth portion in a secondary cell group failure message, wherein the dedicated reason value comprises the number of attempted switched bandwidth portions.

[0219]

[0227] Aspect 23: The method of any of aspects 21 to 22, further comprising receiving, from the UE, a medium access control (MAC) control element indicating a number of uplink listen-before-talk failures on the primary cell or the secondary cell.

[0220]

[0228] Aspect 24: The method of aspect 23, wherein the MAC control element is received on an additional bandwidth portion in a subband for the secondary cell that is different from the first bandwidth portion.

[0221]

[0229] Aspect 25: The method of any of aspects 21 to 24, further comprising receiving, from the secondary node, an indication of a failure for the primary cell based at least in part on a number of uplink listen-before-talk failures for the first bandwidth portion exceeding a threshold.

[0222]

[0230] Aspect 26: A method according to any of aspects 21 to 25, wherein the switching parameters comprise a number of bandwidth portion switches, an indication of which bandwidth portion may be switched to after a failure of another bandwidth portion, a priority order for multiple bandwidth portions in the bandwidth portion switching configuration message, an indication for switching to a bandwidth portion in a different subband, an indication that the same bandwidth portion may be used multiple times for switching, a threshold time between switches to the same bandwidth portion, or a combination thereof.

[0223]

[0231] Aspect 27: An apparatus for wireless communication in a UE, comprising: a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform a method described in any of aspects 1 to 20.

[0224]

[0232] Aspect 28: An apparatus for wireless communication in a UE, comprising at least one means for performing the method of any of aspects 1 to 20.

[0225]

[0233] Aspect 29: A non-transitory computer-readable medium storing code for wireless communication in a UE, the code comprising instructions executable by a processor to perform a method described in any of aspects 1 to 20.

[0226]

[0234] Aspect 30: An apparatus for wireless communication in a base station, comprising: a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform a method as described in any of aspects 21 to 26.

[0227]

[0235] Aspect 31: An apparatus for wireless communication in a base station, the apparatus comprising at least one means for performing the method of any of aspects 21 to 26.

[0228]

[0236] Aspect 32: A non-transitory computer-readable medium storing code for wireless communication in a base station, the code comprising instructions executable by a processor to perform a method described in any of aspects 21 to 26.

[0229]

[0237] Although aspects of an LTE, LTE-A, LTE-A Pro, or NR system may be described as examples, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used throughout much of the description, the techniques described herein may be applicable to networks other than LTE, LTE-A, LTE-A Pro, or NR. For example, the described techniques may be applied to various other wireless communication systems, such as Ultra Mobile Broadband (UMB), IEEE (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash OFDM, and other systems and radio technologies not explicitly mentioned herein.

[0230]

[0238] The information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0231]

[0239] The various example blocks and components described in connection with the disclosure herein may be implemented or performed using a general-purpose processor, a DSP, an ASIC, a CPU, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but alternatively, the processor may be any processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

[0232]

[0240] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted via a computer-readable medium as one or more instructions or code. Other examples and implementations are within the scope of this disclosure and the appended claims. For example, due to the nature of software, the functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or any combination thereof. Features implementing the functions may also be physically located in various locations, including being distributed such that portions of the functions are implemented in different physical locations.

[0233]

[0241] Computer-readable media includes both non-transitory computer storage media and communication media, including any medium that facilitates transfer of a computer program from one place to another. Non-transitory storage media may be any available medium that can be accessed by a general-purpose or special-purpose computer. By way of example, and not limitation, non-transitory computer-readable media may include RAM, ROM, Electrically Erasable Programmable Read Only Memory (EEPROM), Flash memory, Compact Disc (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included within the definition of computer-readable media. As used herein, disk and disc include CDs, laser discs, optical discs, digital versatile discs (DVDs), floppy discs, and Blu-ray discs, where disks typically reproduce data magnetically and discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

[0234]

[0242] As used herein, including in the claims, "or" used in a list of items (e.g., a list of items ending with a phrase such as "at least one of" or "one or more of") indicates an inclusive list, such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also, the phrase "based on" as used herein is not to be construed as a reference to a closed set of conditions. For example, an example step described as "based on condition A" could be based on both condition A and condition B without departing from the scope of the present disclosure. In other words, the phrase "based on" as used herein is to be construed similarly to the phrase "based at least in part on."

[0235]

[0243] In the accompanying figures, similar components or features may have the same reference label. Furthermore, various components of the same type may be distinguished by following the reference label with a dash and a second label that distinguishes between the similar components. If only a first reference label is used herein, the description is applicable to any of the similar components having the same first reference label, regardless of a second reference label or other subsequent reference label.

[0236]

[0244] The description set forth herein with reference to the accompanying drawings describes exemplary configurations and does not necessarily represent every example that may be implemented or that is within the scope of the claims. As used herein, the term "example" means "serving as an example, instance, or illustration" and does not mean "preferred" or "advantageous over other examples." The detailed description includes specific details for the purpose of providing an understanding of the described techniques. However, these techniques may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

[0237]

[0245] The description herein is provided to enable any person skilled in the art to make or use the disclosure. Various modifications of the disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. 1. A method for wireless communication in a user equipment (UE), comprising: receiving a bandwidth portion switch configuration message from a base station comprising switching parameters; performing a plurality of listen-before-talk procedures for the first bandwidth portion; switching to a second bandwidth portion for uplink communication with the base station based at least in part on the switching parameter and a number of failures associated with the plurality of listen-before-talk procedures for the first bandwidth portion; A method comprising:

2. performing a random access procedure on the second bandwidth portion based at least in part on switching to the second bandwidth portion; The method of claim 1 further comprising:

3. transmitting a first message of the random access procedure; determining that a threshold number of attempts to transmit the first message has been met; declaring a radio link failure or switching to a third bandwidth portion, or a combination thereof, based at least in part on the threshold number of attempts to transmit the first message being met; The method of claim 2 further comprising:

4. determining that a number of uplink listen-before-talk failures for the second bandwidth portion exceeds a threshold; switching to a third bandwidth portion based at least in part on the number of uplink listen-before-talk failures for the second bandwidth portion exceeding the threshold; and 3. The method of claim 2, further comprising: aborting the random access procedure on the second bandwidth portion.

5. determining that an uplink listen-before-talk failure for a number of the first bandwidth portions occurs in a primary-secondary cell; transmitting in a secondary cell group failure message a dedicated cause value for the number of uplink listen-before-talk failures for the first bandwidth portion; The method of claim 1 further comprising:

6. The method of claim 5 , wherein the dedicated reason value comprises a number of switched bandwidth portions attempted.

7. determining that an uplink listen-before-talk failure for a number of the first bandwidth portions occurs in a secondary cell; transmitting a Medium Access Control (MAC) control element indicating the uplink listen-before-talk failure on a primary cell or an additional secondary cell; The method of claim 1 further comprising:

8. transmitting the MAC control element determining that the secondary cell comprises a plurality of bandwidth portions including the first bandwidth portion; transmitting the MAC control element on an additional bandwidth portion in a subband for the secondary cell that is different from the first bandwidth portion; The method of claim 7, comprising:

9. determining to switch to the second bandwidth portion based at least in part on the number of failures associated with the plurality of listen-before-talk procedures for the first bandwidth portion meeting a threshold; The method of claim 1 further comprising:

10. performing a master cell group recovery procedure via the secondary node based at least in part on determining that a number of uplink listen-before-talk failures for the second bandwidth portion meets the threshold and that the number of uplink listen-before-talk failures for the second bandwidth portion occur in the primary cell; The method of claim 9 further comprising:

11. Performing the master cell group recovery procedure via the secondary node includes: sending to the secondary node an indication of failure for the primary cell based at least in part on the number of uplink listen-before-talk failures for the second bandwidth portion exceeding the threshold; The method of claim 10, comprising:

12. determining a number of bandwidth portion switches based at least in part on the switch parameter, wherein the switch to the second bandwidth portion is based at least in part on the number of bandwidth portion switches; The method of claim 1 further comprising:

13. 13. The method of claim 12, wherein the switching parameters comprise an indication of one or more of an upper threshold number of bandwidth portion switching, a lower threshold number of bandwidth portion switching, a fixed number of bandwidth portion switching, or a combination thereof.

14. selecting the second bandwidth portion based at least in part on the switching parameter; The method of claim 1 further comprising:

15. 15. The method of claim 14, wherein the switching parameters comprise an indication of a priority order of bandwidth portions, and selecting the second bandwidth portion is based at least in part on the priority order of the bandwidth portions.

16. 15. The method of claim 14, wherein the switching parameters comprise an indication of a subband constraint for the second bandwidth portion, and selecting the second bandwidth portion is based at least in part on the subband constraint.

17. 17. The method of claim 16, wherein the second bandwidth portion is entirely in a second sub-band that is different from a first sub-band of the first bandwidth portion, or a subset of the second bandwidth portion is in the second sub-band that is different from the first sub-band of the first bandwidth portion, or a combination thereof.

18. 15. The method of claim 14, wherein the switching parameters comprise an indication that switching to the same bandwidth portion multiple times is permitted, and selecting the second bandwidth portion is based at least in part on the indication.

19. determining a time threshold for switching to the same bandwidth portion, wherein selecting the second bandwidth portion is based at least in part on a time between successive switches to the second bandwidth portion satisfying the time threshold.

20. The method of claim 18.

20. performing one or more listen-before-talk procedures for the second bandwidth portion; and switching to a third bandwidth portion in accordance with the bandwidth portion switching configuration message and the switching parameters based at least in part on a number of failures associated with the one or more listen-before-talk procedures for the second bandwidth portion; The method of claim 1 further comprising:

21. 1. A method for wireless communication in a base station, comprising: sending a bandwidth fraction switching configuration message to the UE, the bandwidth fraction switching configuration message comprising switching parameters; receiving a first uplink transmission in a first bandwidth portion from the UE; receiving an uplink transmission in a second bandwidth portion from the UE based at least in part on the switching parameter and an uplink listen-before-talk failure; A method comprising:

22. 22. The method of claim 21, further comprising: receiving, from the UE, in a secondary cell group failure message, a dedicated reason value for a number of uplink listen-before-talk failures for the first bandwidth portion, wherein the dedicated reason value comprises a number of attempted switched bandwidth portions.

23. receiving a medium access control (MAC) control element from the UE indicating a number of uplink listen-before-talk failures for the first bandwidth portion on a primary cell or a secondary cell; 22. The method of claim 21 further comprising:

24. 24. The method of claim 23, wherein the MAC control element is received on an additional bandwidth portion in a subband for the secondary cell that is different from the first bandwidth portion.

25. receiving, from a secondary node, an indication of failure for the primary cell based at least in part on a number of uplink listen-before-talk failures for the first bandwidth portion exceeding a threshold; 22. The method of claim 21 further comprising:

26. 22. The method of claim 21, wherein the switching parameters comprise a number of bandwidth portion switches, an indication of which bandwidth portion may be switched to after a failure of another bandwidth portion, a priority order for multiple bandwidth portions in the bandwidth portion switching configuration message, an indication to switch to a bandwidth portion in a different subband, an indication that the same bandwidth portion may be used multiple times for switching, a threshold time between switches to the same bandwidth portion, or a combination thereof.

27. 1. An apparatus for wireless communication in a user equipment (UE), comprising: means for receiving, from a base station, a bandwidth portion switch configuration message comprising switching parameters; means for implementing a plurality of listen-before-talk procedures for the first bandwidth portion; means for switching to a second bandwidth portion for uplink communication with the base station based at least in part on the switching parameter and a number of failures associated with the plurality of listen-before-talk procedures for the first bandwidth portion; An apparatus comprising:

28. means for performing a random access procedure on the second bandwidth portion based at least in part on switching to the second bandwidth portion; 28. The apparatus of claim 27, further comprising:

29. means for transmitting a first message of the random access procedure; means for determining that a threshold number of attempts to transmit the first message has been met; means for declaring a radio link failure or switching to a third bandwidth portion, or a combination thereof, based at least in part on the threshold number of attempts to transmit the first message being met; 30. The apparatus of claim 28, further comprising:

30. means for determining that a number of uplink listen-before-talk failures for the second bandwidth portion exceeds a threshold; means for switching to a third bandwidth portion based at least in part on the number of uplink listen-before-talk failures for the second bandwidth portion exceeding the threshold; and means for aborting the random access procedure on the second bandwidth portion; 30. The apparatus of claim 28, further comprising:

31. means for determining that an uplink listen-before-talk failure for a number of the first bandwidth portions occurs in a primary / secondary cell; means for transmitting in a secondary cell group failure message a dedicated cause value for the number of uplink listen-before-talk failures for the first bandwidth portion; 28. The apparatus of claim 27, further comprising:

32. 32. The apparatus of claim 31, wherein the dedicated reason value comprises a number of switched bandwidth portions attempted.

33. means for determining that an uplink listen-before-talk failure for a number of the first bandwidth portions occurs in a secondary cell; means for transmitting a Medium Access Control (MAC) control element indicating said uplink Listen-Before-Talk failure on a primary cell or an additional secondary cell; 28. The apparatus of claim 27, further comprising:

34. means for determining that the secondary cell comprises a plurality of bandwidth portions including the first bandwidth portion; means for transmitting the MAC control element on an additional bandwidth portion in a subband for the secondary cell that is different from the first bandwidth portion; 34. The apparatus of claim 33, further comprising:

35. means for determining to switch to the second bandwidth portion based at least in part on the number of failures associated with the plurality of listen-before-talk procedures for the first bandwidth portion meeting a threshold; 28. The apparatus of claim 27, further comprising:

36. means for implementing a master cell group recovery procedure via a secondary node based at least in part on determining that a number of uplink listen-before-talk failures for the second bandwidth portion meets the threshold and that said number of uplink listen-before-talk failures for the second bandwidth portion occur in a primary cell; 36. The apparatus of claim 35, further comprising:

37. The means for performing the master cell group recovery procedure via the secondary node comprises: means for transmitting, to the secondary node, an indication of failure for the primary cell based at least in part on the number of uplink listen-before-talk failures for the second bandwidth portion exceeding the threshold; 37. The apparatus of claim 36, comprising:

38. means for determining a number of bandwidth portion switches based at least in part on the switch parameters, wherein the switch to the second bandwidth portion is based at least in part on the number of bandwidth portion switches; 28. The apparatus of claim 27, further comprising:

39. 39. The apparatus of claim 38, wherein the switching parameters comprise an indication of one or more of an upper threshold number of bandwidth portion switching, a lower threshold number of bandwidth portion switching, a fixed number of bandwidth portion switching, or a combination thereof.

40. means for selecting the second bandwidth portion based at least in part on the switching parameters; 28. The apparatus of claim 27, further comprising:

41. 41. The apparatus of claim 40, wherein the switching parameters comprise an indication of a priority order of bandwidth portions, and wherein selecting the second bandwidth portion is based at least in part on the priority order of the bandwidth portions.

42. 41. The apparatus of claim 40, wherein the switching parameters comprise an indication of a subband constraint for the second bandwidth portion, and wherein selecting the second bandwidth portion is based at least in part on the subband constraint.

43. 43. The apparatus of claim 42, wherein the second bandwidth portion is entirely in a second sub-band that is different from a first sub-band of the first bandwidth portion, or a subset of the second bandwidth portion is in the second sub-band that is different from the first sub-band of the first bandwidth portion, or a combination thereof.

44. 41. The apparatus of claim 40, wherein the switching parameters comprise an indication that switching to the same bandwidth portion multiple times is permitted, and selecting the second bandwidth portion is based at least in part on the indication.

45. means for determining a time threshold for switching to the same bandwidth portion; selecting the second bandwidth portion is based at least in part on a time between successive switches to the second bandwidth portion satisfying the time threshold.

45. The apparatus of claim 44.

46. means for implementing one or more listen-before-talk procedures for the second bandwidth portion; 28. The apparatus of claim 27, further comprising: means for switching to a third bandwidth portion in accordance with the bandwidth portion switching configuration message and the switching parameters based at least in part on a number of failures associated with the one or more listen-before-talk procedures for the second bandwidth portion.

47. 1. An apparatus for wireless communication at a base station, comprising: means for transmitting, to the UE, a bandwidth portion switch configuration message comprising switching parameters; means for receiving a first uplink transmission in a first bandwidth portion from the UE; means for receiving an uplink transmission in a second bandwidth portion from the UE based at least in part on the switching parameter and an uplink listen-before-talk failure; An apparatus comprising:

48. means for receiving, from the UE, in a secondary cell group failure message, a dedicated reason value for a number of uplink listen-before-talk failures for the first bandwidth portion, wherein the dedicated reason value comprises a number of attempted switched bandwidth portions; 48. The apparatus of claim 47, further comprising:

49. means for receiving, from the UE, a Medium Access Control (MAC) control element indicating a number of uplink listen-before-talk failures for the first bandwidth portion on a primary cell or a secondary cell; 48. The apparatus of claim 47, further comprising:

50. 50. The apparatus of claim 49, wherein the MAC control element is received on an additional bandwidth portion in a subband for the secondary cell that is different from the first bandwidth portion.

51. means for receiving, from a secondary node, an indication of a failure for the primary cell based at least in part on a number of uplink listen-before-talk failures for the first bandwidth portion exceeding a threshold; 48. The apparatus of claim 47, further comprising:

52. 48. The apparatus of claim 47, wherein the switching parameters comprise a number of bandwidth portion switches, an indication of which bandwidth portion may be switched to after a failure of another bandwidth portion, a priority order for multiple bandwidth portions in the bandwidth portion switching configuration message, an indication to switch to a bandwidth portion in a different subband, an indication that the same bandwidth portion may be used multiple times for switching, a threshold time between switches to the same bandwidth portion, or a combination thereof.

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