CN114615692B - Apparatus and method for wireless communication - Google Patents

Abstract

An apparatus and method of wireless communication are provided. A method of a User Equipment (UE) includes configuring a Listen Before Talk (LBT) failure recovery procedure by a base station, detecting an LBT failure for each Uplink (UL) bandwidth part (BWP), and triggering UL LBT failure Medium Access Control (MAC) Control Elements (CEs) of one or more serving cells for triggering the LBT failure. This may solve the problems of the prior art, provide good communication performance for any serving cell triggering LBT failure triggering MAC CE of UL LBT failure, and/or provide high reliability.

Description

Apparatus and method for wireless communication

The present application is a divisional application filed by the chinese patent office at 11/18/2020 with application number 202080047286.2 entitled "device and method for wireless communication", the entire contents of which are incorporated herein by reference.

Technical Field

The present application relates to the field of communication systems, and more particularly, to an apparatus and method for wireless communication that can provide good communication performance and/or high reliability.

Background

Wireless communication systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These wireless communication systems may support communication with multiple users by sharing available system resources (e.g., time, frequency, and power). Examples of such multiplexed access systems include fourth generation (4G) systems, such as long term evolution (long term evolution, LTE) systems and fifth generation (5G) systems, which may be referred to as New Radio (NR) systems. A wireless multiplexed access communication system may include a number of base stations or network access nodes, each supporting communication for multiple communication devices, which may be referred to as User Equipment (UEs).

The wireless communication network may include base stations that may support UE communication. The UE may communicate with the base station over a downlink and an uplink. The downlink refers to a communication link from the base station to the UE, and the uplink refers to a communication link from the UE to the base station. In a wireless communication system operating in a high frequency band, paging (paging) transmission/reception may cause an increase in signaling overhead and power consumption of UEs.

Accordingly, there is a need for an apparatus (e.g., user Equipment (UE) and/or base station) and method of wireless communication that can address the problems of the prior art, trigger a media access control (medium access control, MAC) element (CE) for UL LBT failure for any serving cell that has triggered a listen before talk (listen before talk, LBT) failure event, provide good communication performance, and/or provide high reliability.

Disclosure of Invention

It is an object of the present disclosure to propose an apparatus (e.g., user Equipment (UE) and/or base station) and method of wireless communication that may solve the problems in the prior art, provide good communication performance for any serving cell that has triggered an LBT failure event triggering a MAC CE of UL LBT failure, and/or provide high reliability.

In a first aspect of the disclosure, a method of wireless communication by a User Equipment (UE) includes configuring a Listen Before Talk (LBT) failure recovery procedure by a base station; detecting LBT failure of each Uplink (UL) bandwidth part (BWP); and triggering a UL LBT failure Medium Access Control (MAC) Control Element (CE) for one or more serving cells for triggering LBT failure.

In a second aspect of the present disclosure, a method of wireless communication of a base station includes configuring a Listen Before Talk (LBT) failure recovery procedure to a User Equipment (UE); controlling the UE to detect a LBT failure of each Uplink (UL) bandwidth part (BWP); and controlling the UE to trigger UL LBT failure Medium Access Control (MAC) Control Elements (CEs) for one or more serving cells for triggering LBT failures.

In a third aspect of the present disclosure, a user equipment includes a memory, a transceiver, and a processor coupled to the memory and the transceiver. The processor is configured by the base station with a Listen Before Talk (LBT) failure recovery procedure. The processor is configured to detect LBT failure for each Uplink (UL) bandwidth part (BWP). The processor is configured to trigger a UL LBT failure Medium Access Control (MAC) Control Element (CE) for one or more serving cells for triggering LBT failure.

In a fourth aspect of the disclosure, a base station includes a memory, a transceiver, and a processor coupled to the memory and the transceiver. The processor is configured to configure a Listen Before Talk (LBT) failure recovery procedure to a User Equipment (UE). The processor is configured to control the UE to detect LBT failure for each Uplink (UL) bandwidth part (BWP). The processor is configured to control the UE to trigger a UL LBT failure Medium Access Control (MAC) Control Element (CE) for triggering one or more serving cells of LBT failure.

In a fifth aspect of the present disclosure, a non-transitory machine-readable storage medium has stored thereon instructions that, when executed by a computer, cause the computer to perform the above-described method.

In a sixth aspect of the present disclosure, a chip includes a processor configured to invoke and run a computer program stored in a memory to cause a device on which the chip is installed to perform the above method.

In a seventh aspect of the present disclosure, a computer-readable storage medium has a computer program stored therein to cause a computer to perform the above method.

In an eighth aspect of the present disclosure, a computer program product comprises a computer program and the computer program causes a computer to perform the above method.

In a ninth aspect of the present disclosure, a computer program causes a computer to perform the above method.

Drawings

In order to more clearly illustrate embodiments of the present disclosure or related art, drawings in the embodiments will be briefly described below. It is apparent that these figures are merely some embodiments of the present disclosure and that one of ordinary skill in the art can obtain other figures from these figures without the need for a precondition.

Fig. 1 is a block diagram of one or more User Equipments (UEs) and a wireless communication base station in a communication network system according to one embodiment of the present disclosure.

Fig. 2 is a flowchart of a method of wireless communication performed by a User Equipment (UE) according to one embodiment of the present disclosure.

Fig. 3 is a flowchart of a method of wireless communication performed by a base station according to one embodiment of the present disclosure.

Fig. 4 is a schematic diagram of an eight-bit group (octet) LBT failed MAC CE in accordance with one embodiment of the present disclosure.

Fig. 5 is a schematic diagram of a four octet LBT failed MAC CE according to one embodiment of the present disclosure.

Fig. 6 is a block diagram of a system for wireless communication according to one embodiment of the present disclosure.

Detailed Description

Technical matters, structural features, achieved objects and effects of the embodiments of the present disclosure are described in detail as follows with reference to the accompanying drawings. In particular, the terminology in the embodiments of the disclosure is for the purpose of describing particular embodiments only, and is not intended to be limiting of the disclosure.

Unlicensed spectrum is a shared spectrum. Communication devices of different communication systems may use unlicensed spectrum as long as the unlicensed spectrum meets regulatory requirements of a country or region for a certain spectrum. There is no need to apply for proprietary spectrum grants to the government.

In order for various communication systems using unlicensed spectrum for wireless communication to coexist in the spectrum in a friendly manner, some countries or regions prescribe regulatory requirements that must be met using unlicensed spectrum. For example, the communication device follows a Listen Before Talk (LBT) procedure, i.e. the communication device needs to perform channel sensing before transmitting a signal on a channel. When the LBT result shows that the channel is idle, the communication device can perform signal transmission; otherwise, the communication device is not capable of signal transmission. To ensure fairness, once a communication device successfully occupies a channel, the transmission time cannot exceed the maximum channel occupation time (maximum channel occupancy time, MCOT).

On an unlicensed carrier, for a channel occupation time obtained by a base station, it may share the channel occupation time to a User Equipment (UE) for transmitting an uplink signal or an uplink channel. In other words, when the base station shares its own channel occupation time with the UE, the UE may acquire the channel using an LBT mode having a higher priority than that used by the UE itself, thereby acquiring the channel with a greater probability. LBT is also known as a channel access procedure. The UE performs the channel access procedure prior to the transmission and starts to perform the transmission if the channel access procedure is successful, i.e. the channel is perceived as idle. If the channel access procedure is unsuccessful, i.e. the channel is perceived as non-idle, the UE cannot perform the transmission.

In the present discussion, the mechanism of handling Uplink (UL) LBT failure is agreed to be introduced: a mechanism is employed in the medium access control (medium access control, MAC) specification to handle so-called UL LBT failure, where "persistent UL LBT failure" is used for problem detection, at least for problem detection of UL transmissions of scheduling requests (scheduling request, SR), random access channels (random access channel, RACH) and physical uplink shared channels (physical uplink shared channel, PUSCH).

In the present discussion, a further protocol has been achieved for the UL LBT failure: the layer 2 (L2) LBT failure mechanism may take into account any LBT failure regardless of UL transmission type. The UL LBT failure mechanism, regardless of UL transmission type, may have the same recovery mechanism for all failures. The basic mechanism, further enhancements do not exclude: a "threshold" of maximum LBT failure number that triggers a "sustained" LBT failure event will be used. A timer and a counter are introduced, which is reset when the timer expires and which is incremented when a UL LBT failure occurs. The timer is started/restarted when the UL LBT failure occurs. Summary of the basic mechanisms: the mechanisms inspired by beam failure detection (Beam failure detection, BFD) appear to be supported by many but there are also some issues. It is agreed as a basic mechanism for further review at a later time to see if further improvement is required. UL LBT failure is detected per bandwidth part (BWP). The User Equipment (UE) will report persistent UL LBT failures that occur on one primary secondary cell (primary secondary cell, PSCell) and secondary cell (SCell). It is assumed that SCell failure reports for Beamforming (BF) are reused.

In addition, in the present discussion, there are agreements as follows. MAC relies on receiving UL LBT failure notification from the physical layer to detect persistent UL LBT failure. If there is another BWP with a configured RACH resource, one UE switches to another BWP and starts RACH when persistent LBT failure on primary cell (PCell) or PSCell is declared. If the persistent UL LBT failure is detected on the PCell and UL LBT failure is detected on "N" possible bwtps, the UE performs radio link failure (radio link failure, RLF) recovery. When a persistent uplink LBT failure is detected on the PSCell, the UE notifies a Master Node (MN) through a secondary cell group (secondary cell group, SCG) failure information procedure after detecting a persistent UL LBT failure on "N" bwtps. "N" is the number of configured BWP with configured physical random access channel (physical random access channel, PRACH) resources. If N is greater than 1, a decision is made by the UE as to which BWP to select. When a persistent uplink LBT failure is detected on one SCell, a new MAC Control Element (CE) is used to report the persistent uplink LBT failure to the node to which the SCell belongs. The further research issue (FFS) includes: whether the persistent uplink LBT failure on the PCell can be reported using the MAC CE.

Some current techniques are related to the field of UL LBT failure. More specifically, some of the current techniques are as follows.

UL LBT failure for SCell or multiple scells:

there are some further research (FFS) issues with regard to persistent UL LBT failure detection on SCell. FFS, what the priority of the MAC CE is in the logical channel priority handling (logical channel prioritization, LCP). FFS (FFS): whether we need to deal with the situation where no subsequent UL resources are available. FFS whether we need to restrict the transmission of MAC CE to other BWP than the BWP advertising LBT failure.

For the first FFS, in some aspects of some embodiments of the present disclosure, an SCell may have some problems if the UE detects a persistent UL LBT failure, similar to the case when the UE announces a beam failure of the SCell, so some aspects consider that the MAC CE for reporting the SCell LBT problem may have a similar priority as the beam failure recovery (beam failure recovery, BFR) MAC CE in question.

Proposal 1: in some embodiments of the present disclosure, the MAC CE for UL LBT problem may have a similar priority as the BFR MAC CE.

Regarding the second FFS, some views consider similar to the case of the BFR MAC CE, when no available UL resources are available, the UE needs to send a scheduling request SR to the network to request uplink resources, otherwise the network will not be aware of UL LBT problems.

Proposal 2: in some embodiments of the present disclosure, similar to the BFR MAC CE, if there are no UL resources available, the UE may trigger a scheduling request, SR, for transmitting a MAC CE regarding SCell UL LBT problem.

With respect to the third FFS, there is no need for a restriction that the MAC CE should be transmitted on a different serving cell outside the SCell with the UL LBT problem. The reason is that the persistent LBT failure reflects only one period of channel occupancy, and does not mean that the channel is always occupied.

Proposal 3 in some embodiments of the present disclosure, the MAC CE need not be restricted from transmitting on a different serving cell outside the SCell where the UL LBT problem exists.

The MAC CE should be used to indicate which SCell has the persistent UL LBT failure, and if there is already a MAC CE triggered but not sent to the network, the MAC CE need not be triggered again.

Proposal 4: in some embodiments of the present disclosure, if there is already a trigger MAC CE to indicate a persistent UL LBT failure for the SCell, there is no need to re-trigger the MAC CE.

Regarding MAC CE formats, there are several views to trigger the persistent UL LBT failure independently between different scells. It may be the case that if these scells have the persistent UL LBT failure, multiple MAC CEs are triggered for multiple different scells. From this point of view, it is beneficial to incorporate all the relevant multiple scells with the persistent UL LBT failure into one MAC CE format, that is, the MAC CE format should support multiple entries to represent multiple scells with the persistent UL LBT failure.

Proposal 5: in some embodiments of the present disclosure, the MAC CE format should support multiple entries to indicate all scells that have declared the persistent UL LBT failure.

UL LBT failure of SpCell:

in the present discussion, the following is agreed: if the PSCell detects persistent LBT failure, the UE may report the LBT failure to a Master Node (MN) through an SCG failure information procedure.

When a persistent uplink LBT failure is detected on the PSCell, the UE informs the master node MN through an SCG failure information procedure after detecting a persistent UL LBT failure on "N" bwtps.

Upon detection of persistent UL LBT failures on "N" BWPs, the LBT failures for PSCell are reported by means of SCG failure information. The network should be aware of LBT failure on PSCell, and at present, there are different conditions that can trigger SCG failure procedure. In order for the network to distinguish between the LBT failure and other situations, it is proposed to add a new failure type when reporting SCG failure information SCGFailureInformation.

Proposal 6: in some embodiments of the present disclosure, a new failure type of PSCell-persistent UL LBT failure is added to the SCG failure information SCGFailureInformation.

If proposal 6 is acknowledged, it is not necessary to trigger a MAC CE for the PSCell if there is a persistent UL LBT failure.

There remains in the present discussion an FFS, i.e. whether MAC CE is applied to PCell.

In some aspects, it is not considered necessary, i.e., MAC CE is not applied to PCell either. The reason is that the network may learn about the LBT failure problem on the PCell based on BWP handover, i.e., BWP handover to another non-initial BWP. Even though the PCell may have only a single initial BWP, some companies may consider that in this case the gNB may not distinguish the LBT failure problem from other causes. However, some views consider that the UE only initiates RLF procedure in case of PCell LBT problem, and there is no other special handling for this case. Thus, even though in some cases the gNB may not distinguish the situation from other situations, there should be no problem.

Proposal 7: in some embodiments of the present disclosure, the UE does not trigger the MAC CE when a persistent UL LBT failure on the SpCell is declared.

Regarding how to report the persistent UL LBT failure, the following is agreed: MAC CE is used for SCell. However, for SpCell (including PCell and PSCell), no conclusion has been made. A possible problem is that the network may not know how to trigger RACH if the UE fails to trigger UL LBT and switches UL BWP for SpCell.

Accordingly, some embodiments of the present disclosure propose an apparatus (e.g., a User Equipment (UE) and/or a base station) and a method of wireless communication that may solve the problems in the prior art, provide good communication performance for any serving cell that triggers LBT failure triggering MAC CE of UL LBT failure, and/or provide high reliability.

Fig. 1 illustrates, in some embodiments, one or more User Equipments (UEs) 10 and base stations (e.g., gnbs or enbs) 20 for wireless communications in a communication network system 30 according to one embodiment of the present disclosure. The communication network system 30 includes the one or more UEs 10 and the base station 20. The one or more UEs 10 may include a memory 12, a transceiver 13, and a processor 11 coupled with the memory 12 and the transceiver 13. The base station 20 may include a memory 22, a transceiver 23, and a processor 21 coupled with the memory 22 and the transceiver 23. The processor 11 or 21 may be configured to implement the proposed functions, procedures and/or methods described in this specification. The layers of the radio interface protocol may be implemented in the processor 11 or 21. The memory 12 or 22 is operatively coupled with the processor 11 or 21 and stores various information to operate the processor 11 or 21. The transceiver 13 or 23 is operatively coupled to the processor 11 or 21, the transceiver 13 or 23 transmitting and/or receiving radio signals.

The processor 11 or 21 may include an application-specific integrated circuit (ASIC), other chipset, logic circuit, and/or data processing device. The memory 12 or 22 may include read-only memory (ROM), random-access memory (random access memory, RAM), flash memory, memory cards, storage media, and/or other storage devices. The transceiver 13 or 23 may include baseband circuitry that processes radio frequency signals. When the present embodiments are implemented in software, the techniques described herein may be implemented with modules (e.g., procedures, functions, and so on) that perform the functions described herein. These modules may be stored in the memory 12 or 22 and executed by the processor 11 or 21. The memory 12 or 22 may be implemented within the processor 11 or 21 or external to the processor 11 or 21, in which case those can be communicatively coupled to the processor 11 or 21 via various means as is known in the art.

In some embodiments, the processor 11 is configured by the base station 20 to have a Listen Before Talk (LBT) failure recovery procedure. The processor 11 is configured to detect LBT failure of each Uplink (UL) bandwidth part (BWP). The processor 11 is configured for triggering a UL LBT failure Medium Access Control (MAC) Control Element (CE) for one or more serving cells for triggering LBT failure. This may solve the problems of the prior art, provide good communication performance for any serving cell triggering LBT failure triggering MAC CE of UL LBT failure, and/or provide high reliability.

In some embodiments, the processor 21 is configured to configure a Listen Before Talk (LBT) failure recovery procedure to the User Equipment (UE) 10. The processor 21 is configured to control the UE 10 to detect LBT failure of each Uplink (UL) bandwidth part (BWP). The processor 21 is configured to control the UE 10 to trigger UL LBT failure Medium Access Control (MAC) Control Elements (CEs) for triggering one or more serving cells of LBT failure. This may solve the problems of the prior art, provide good communication performance for any serving cell triggering LBT failure triggering MAC CE of UL LBT failure, and/or provide high reliability.

Fig. 2 illustrates a method 200 of wireless communication of a User Equipment (UE) in accordance with one embodiment of the present disclosure. In some embodiments, the method 200 includes: block 202, configured by the base station with Listen Before Talk (LBT) failure recovery procedures, block 204, for detecting LBT failures for each Uplink (UL) bandwidth portion (BWP), and block 206, for triggering UL LBT failure Medium Access Control (MAC) Control Elements (CEs) of one or more serving cells for triggering the LBT failures. This may solve the problems of the prior art, provide good communication performance for any serving cell triggering LBT failure triggering MAC CE of UL LBT failure, and/or provide high reliability.

Fig. 3 illustrates a method 300 of wireless communication of a base station according to one embodiment of the present disclosure. In some embodiments, the method 300 includes: block 302 for configuring a Listen Before Talk (LBT) failure recovery procedure to a User Equipment (UE), block 304 for controlling the UE to detect an LBT failure for each Uplink (UL) bandwidth portion (BWP), and block 306 for triggering UL LBT failure Medium Access Control (MAC) Control Elements (CEs) of one or more serving cells for triggering the LBT failure. This may solve the problems of the prior art, provide good communication performance for any serving cell triggering LBT failure triggering MAC CE of UL LBT failure, and/or provide high reliability.

In some embodiments, the method further comprises transmitting, by the UE, a MAC CE to the base station, the MAC CE having serving cell information of the MAC CE configured to trigger the UL LBT failure. In some embodiments, the UE cancels one or more triggered MAC CEs if the MAC CE has been transmitted on the one or more serving cells. In some embodiments, the serving cell information of the MAC CE includes at least one of: reporting of a failed cell; a MAC CE format configured to support an entry for indicating one or more cells announcing the LBT failure; one or more cell indexes of the UL LBT failed MAC CE where the LBT failure occurs; or BWP related information in the MAC CE. In some embodiments, the LBT failure comprises a persistent LBT failure. In some embodiments, if the UE declares persistent LBT failure for an activated UL BWP and if the one or more serving cells include one or more secondary cells (scells), the UE instructs a multiplexing and assembling entity to include the UL LBT failed MAC CE in a subsequent uplink transmission. In some embodiments, the uplink transmission does not occur on one or more scells that have declared the persistent LBT failure.

In some embodiments, the User Equipment (UE) triggers a Scheduling Request (SR) to request UL grant (UL grant) if no UL resources are available on one or more scells for which the persistent LBT failure has not been declared and/or on one or more special cells (spcells). In some embodiments, if the UE announces persistent LBT failure of the activated UL BWP and if one or more serving cells include one or more special cells (spcells), the UE performs at least one of: if the persistent LBT failure is declared in one or more UL BWPs configured with one or more Physical Random Access Channel (PRACH) occasions in the one or more special cells, the user equipment indicates the persistent LBT failure to one or more upper layers; a MAC CE that instructs the multiplexing and assembling entity to include the UL LBT failure in the subsequent uplink transmission; if there are no UL resources available on another or other serving cell for which the persistent LBT failure has not been declared, the user equipment triggers a Scheduling Request (SR) to request UL grant; in the one or more special cells, switching the activated UL BWP to one UL BWP configured with one or more PRACH occasions and not yet announcing the persistent LBT failure; or initiate a random access procedure.

In some embodiments, if a RACH procedure is successfully performed, the UE includes the LBT failed MAC CE in message 3 (msg 3) of the random access procedure. In some embodiments, if the UE successfully transmits the UL LBT failed MAC CE to the base station, the UE cancels one or more MAC CE triggers configured to trigger the one or more serving cells for the persistent LBT failure. In some embodiments, the one or more MAC CE triggers include one or more triggered MAC CEs of the UL BWP for the one or more special cells SpCell. In some embodiments, the format of the UL LBT failed MAC CE includes at least one of: a first format including a bitmap of a maximum number of serving cells equal in size to a Carrier Group (CG) and/or a bitmap of a maximum number of UL BWPs equal in size to the SpCell; or a second format including an SCell index for the user equipment to announce the persistent LBT failure and/or a BWP index for the user equipment to announce the persistent LBT failure. In some embodiments, the first format includes a bitmap having a size equal to a maximum number of PCell plus SCell for one Master Cell Group (MCG). In some embodiments, the first format includes a bitmap having a size equal to a PSCell of a Secondary Cell Group (SCG) plus a maximum number of scells. In some embodiments, if the corresponding serving cell declares that the persistent LBT fails, the corresponding bit field of the bitmap of the first format is set to 1.

In some embodiments, the first format including the bitmap of the maximum number of UL BWP of the size equal to the SpCell includes 4 UL BWP of PCell and 4 UL BWP of PSCell. In some implementations, if the respective UL BWP of the SpCell declares the persistent LBT failure, the respective bit field of the bitmap of the first format is set to 1. In some embodiments, the LBT failure recovery procedure comprises a persistent LBT failure recovery procedure, and the persistent LBT failure recovery procedure is configured to a MAC entity of the UE through a radio resource control (radio resource control, RRC) of the base station. In some embodiments, the persistent LBT failure for each UL BWP is detected by calculating an LBT failure indication for all UL transmissions from one or more lower layers of the user equipment to the MAC entity. In some embodiments, the RRC configures at least one of the following parameters in the persistent LBT failure recovery procedure: LBT failure event maximum count for persistent LBT failure detection LBT-FailureInstanceMaxCount; or an LBT failure detection timer LBT-failuredetection timer for persistent LBT failure detection. In some embodiments, the following UE variables are used for the persistent LBT failure detection: LBT COUNTER lbt_counter: the counter for LBT failure indication is initially set to 0.

In some embodiments, for each active serving cell configured with the LBT failure recovery procedure, the MAC entity performs at least one of: if the LBT failure indication has been received from the one or more lower layers, the MAC entity starts or restarts the LBT failure detection timer LBT-Failuredetection timer and/or increases LBT_COUNTER by 1. In some embodiments, the MAC entity declares the persistent LBT failure of the activated UL BWP if the lbt_counter is greater than or equal to an LBT failure event maximum count LBT-failureimxcount. In some embodiments, if the serving cell is an SCell, and if uplink synchronization channel (UL-SCH) resources are available for new transmissions on the serving cell for which the persistent LBT failed that has not been triggered, and the UL-SCH resources may accommodate the UL LBT failed MAC CE plus its sub-header, as a result of logical channel priority processing, the MAC entity instructs the multiplexing and assembling entity to generate the UL LBT failed MAC CE. In some embodiments, the MAC entity triggers a Scheduling Request (SR) for the persistent LBT failure if the serving cell is an SCell and if no UL-SCH resources are available for a new transmission on the serving cell that has not triggered the persistent LBT failure. In some embodiments, if the serving cell is a SpCell, and if the persistent LBT failure has been declared in all UL BWPs configured with PRACH occasions in the SpCell, the MAC entity indicates the persistent LBT failure to the one or more upper layers of the user equipment.

In some embodiments, if the serving cell is a SpCell, the MAC entity performs at least one of: in SpCell, the UL BWP to which the activated UL BWP is switched is configured with one PRACH occasion, and the persistent LBT failure for the UL BWP has not yet been declared; performing a BWP operation; or initiate a random access procedure. In some embodiments, if the serving cell is a SpCell, the MAC entity instructs the multiplexing and assembling entity to include the LBT failed MAC CE in msg3 transmission. In some embodiments, the MAC entity sets the lbt_counter to 0 if the LBT failure detection timer LBT-failuredetection timer or LBT failure event maximum count LBT-FailureInstanceMaxCount is reconfigured by the one or more upper layers. In some embodiments, the LBT failed MAC CE is identified by a MAC subheader with a logical channel identifier (logical channel identifier, LCID). In some embodiments, the LBT failed MAC CE has a variable size and includes the following fields: c corresponds to C0, C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14 and C15 of the serving cell of one CG; and B0, B1, B2, and B3 corresponding to BWP indexes of one PCell or PScell.

LBT operation:

in some embodiments, the lower layer may perform an LBT procedure according to which the lower layer does not perform transmission if the channel is identified as occupied. When the lower layer performs an LBT procedure before transmission and the transmission is not performed, an LBT failure indication is transmitted from the lower layer to the MAC entity. Unless otherwise specified, when the LBT procedure is performed for a transmission, the actions specified in the specification are performed regardless of whether an LBT failure indication is received from the lower layer. When the lower layer does not perform the LBT, no LBT failure indication is received from the lower layer.

In some embodiments, the UE may trigger a MAC CE for an uplink LBT failure for any serving cell (e.g., SCell and/or SpCell) that has triggered the uplink LBT failure. The UE may then transmit a MAC CE with at least serving cell information of the MAC CE that triggered the uplink LBT failure. If the MAC CEs have been transmitted on one serving cell, the UE will cancel all the triggered MAC CEs. This may solve the problems in the prior art, provide good communication performance for any serving cell that has triggered an LBT failure to trigger a MAC CE of UL LBT failure, and/or provide high reliability.

The transmitted MAC CE may include all information of the serving cell that has triggered an uplink LBT failure, e.g., the MAC CE may report multiple failed cells, and the MAC CE format should support multiple entries to indicate all of the cells that have declared a persistent UL LBT failure, where the UL LBT MAC CE includes one or more cell indexes where the UL LBT failure occurred. Further, since for SpCell (PCell and PSCell), when the UE declares the UL LBT failure of the activated UL BWP, the UE will switch the activated UL BWP to another UL BWP (this BWP configures RACH resources). Thus, the network may need to learn the UL BWP information of the SpCell that the UE announces the UL LBT failure. Thus, optionally, the UE may further include BWP related information in the MAC CE.

In some embodiments, the detailed procedure described above is as follows:

step 1: if the UE announces the persistent LBT failure of the activated UL BWP and if the serving cell is an SCell, the UE instructs a multiplexing and assembling entity to include the LBT failed MAC CE in a subsequent uplink transmission, which should not occur on the SCell that has announced the persistent LBT failure. If there are no UL resources available on the SCell for which the persistent LBT failure has not been declared or on the SpCell, the UE triggers a Scheduling Request (SR) to request UL grant.

Step 2, if the UE declares the persistent LBT failure of the activated UL BWP and the serving cell is SpCell:

step 2.1, if the persistent LBT failure is declared in all UL BWP configured with PRACH occasions in the serving cell: the UE indicates the persistent LBT failure to an upper layer.

Step 2.2, otherwise:

the UE instructs the multiplexing and assembling entity to include the LBT failed MAC CE in a subsequent uplink transmission. Optional behavior. If there are no UL resources available on other serving cells for which persistent LBT failure has not been declared, the UE triggers a scheduling request to request UL grant. Optionally, the UE switches the activated UL BWP to an occasion configured with PRACH in this serving cell and does not announce the persistent LBT failed UL BWP, the UE initiates a random access procedure. Alternatively, if the RACH procedure can be successfully performed, the UE includes the LBT failed MAC CE in message 3 (msg 3) of the random access procedure.

Step 3, if the UE successfully transmits the LBT failed MAC CE, the UE cancels all the MAC CE triggers triggering the persistent LBT failed serving cell, including those for UL BWP triggers of SpCell.

In some embodiments, the format of the LBT failed MAC CE may be at least one of:

format 1:

the MAC CE of the LBT failure includes a bitmap having a size equal to the maximum number of serving cells for one CG, e.g., pcell+multiple scells of MCG and/or pscell+multiple scells of SCG. The respective bit field of the bitmap is set to 1 if the respective serving cell declares the persistent LBT failure. The MAC CE of the LBT failure further includes a bitmap of a maximum UL BWP number equal to SpCell (i.e., 4 for PCell and 4 for PSCell), and if the corresponding UL BWP of the SpCell announces the persistent LBT failure, a corresponding bit field of the bitmap is set to 1.

Format 2:

the LBT failed MAC CE includes an SCell index for the UE to announce the persistent LBT failure. The LBT failed MAC CE includes a BWP index that the UE announces the persistent LBT failure.

In some embodiments, possible implementations of the procedure in the MAC specification are as follows:

LBT failure detection and recovery procedure:

the MAC entity may be RRC configured with persistent LBT failure recovery procedures. Persistent LBT failure per UL BWP is detected by calculating LBT failure indications for all UL transmissions from lower layers to the MAC entity.

The RRC configures the following parameters in lbt-FailureRecoveryConfig:

a maximum LBT failure event count LBT-failureimstancemaxcount for the persistent LBT failure detection;

using the LBT failure detection timer LBT-Failuredetection timer for persistent LBT failure detection;

the following UE variables are used for the persistent LBT failure detection procedure:

lbt_counter: the counter for LBT failure indication is initially set to 0.

For each active serving cell configured with lbt-FailureRecoveryConfig, the MAC entity should:

1> if LBT failure indication has been received from the lower layer:

2> starting or restarting the LBT failure detection timer LBT-failuredetection timer;

2> increment LBT_COUNTER by 1;

2> if lbt_counter > = LBT failure event maximum count LBT-FailureInstanceMaxCount:

3> declaring persistent LBT failure of the activated UL BWP;

3> if this serving cell is an SCell:

4> if UL-SCH resources are available for new transmission on a serving cell that has not triggered persistent LBT failure, and the UL-SCH resources can accommodate the MAC CE and its sub-header of the LBT failure as a result of logical channel priority handling:

5> indicates that the multiplexing and assembling procedure generates the MAC CE of the LBT failure.

4> otherwise:

3> triggers a scheduling request for persistent LBT failure.

3> otherwise (i.e. SpCell):

4> if persistent LBT failure is declared in all UL BWP configured with PRACH occasions in this serving cell:

the 5> upper layer indicates persistent LBT failure.

4> otherwise:

5> in the serving cell, switching the activated UL BWP to a UL BWP configured with PRACH occasions and having no persistent LBT failure announced;

5> performing the BWP operation specified in clause 5.15;

5> initiate a random access procedure (as specified in clause 5.1.1).

6> indicates to the multiplexing and assembling entity that the MAC CE that failed to generate the LBT is included in the msg3 transmission. (this may be implemented in the RACH procedure section).

The editor annotates: this expression conferencing protocol "if there is another BWP with configured RACH resources, the UE switches to another BWP and starts RACH after declaring a persistent LBT failure on PCell or PSCell. "

1> if the LBT failure detection timer LBT-failuredetection timer expires; or alternatively

1> if the LBT failure detection timer LBT-failuredetection timer or LBT-FailureInstanceMaxCount is reconfigured by the upper layer:

2> sets LBT_COUNTER to 0.

LBT failed MAC:

the MAC failed in LBT is identified by a MAC subheader with LCID. It has a variable size, consisting of the following fields, as shown in table 1:

table 1: SCell BFR MAC CE

C7

C6

C5

C4

C3

C2

C1

C0

C15

C14

C13

C12

C11

C10

C9

C8

R

R

R

R

B3

B2

B1

B0

C0 to C15 correspond to the serving cell of one CG. B0 to B3 correspond to the BWP index of the PCell or PScell.

The MAC CE of the LBT failure includes a bitmap of the maximum serving cell number equal to one CG, for example, pcell+multiple scells of MCG, pscell+multiple scells of SCG. The respective bit field of the bitmap is set to 1 if the respective serving cell declares persistent LBT failure. The MAC CE of LBT failure further includes a bitmap having a size equal to the maximum UL BWP number of SpCell (i.e., 4 for PCell and 4 for PSCell), and if the corresponding UL BWP of the SpCell declares persistent LBT failure, the corresponding bit field of the bitmap is set to 1.

Alternatively, table 2 is provided: SCell BFR MAC CE:

the LBT failed MAC CE includes an SCell index for the UE to announce the persistent LBT failure. The LBT failed MAC CE includes a BWP index that the UE announces the persistent LBT failure.

In some embodiments, a MAC CE is provided that fails LBT. The MAC CE for which the LBT of one octet (octet) failed is identified by a MAC subheader with LCID. It has a fixed size and consists of a single octet containing 8C fields, as shown in fig. 4. In some embodiments, the LBT failed MAC CE of four octets is identified by a MAC subheader with an LCID. It has a fixed size and consists of four octets containing 32C-fields as shown in fig. 5. When the highest ServCellIndex of the SCell of the MAC entity that detects LBT failure is less than 8, a single octet format is used, otherwise a four octet format is used.

Ci: if there is a serving cell with ServCellIndex I configured for the MAC entity and if a persistent LBT failure has been triggered in the serving cell and is not cancelled, the field is set to 1, otherwise the field is set to 0.

The commercial benefits of some embodiments are as follows. 1. Solves the problems in the prior art. 2. For any serving cell that has triggered LBT failure, the MAC CE that triggered UL LBT failure. 3. Providing a good communication performance. 4. Providing high reliability. 5. Some embodiments of the present disclosure are applied to 5G-NR chipset vendors, V2X communication system development vendors, automotive manufacturers, including automobiles, trains, trucks, buses, bicycles, motorcycles, helmets, etc., unmanned aerial vehicles (unmanned aerial vehicles), smart phone manufacturers, public safety use communication devices, AR/VR device manufacturers, such as games, conferences/seminars, educational objectives. Some embodiments of the present disclosure are a combination of "technologies/procedures" that may be employed in the 3GPP specifications to create the end product. Some embodiments of the present disclosure may be employed in 5G NR unlicensed band communications. Some embodiments of the present disclosure propose a technical mechanism.

Fig. 6 is a block diagram of an example system 700 for wireless communication according to one embodiment of the disclosure. The embodiments described herein may be implemented into a system using any suitably configured hardware and/or software. Fig. 6 illustrates that the system 700 includes Radio Frequency (RF) circuitry 710, baseband circuitry 720, application circuitry 730, memory/storage 740, display 750, camera 760, sensor 770, and input/output (input/output) interface 780, coupled to one another at least as shown. The application circuitry 730 may include a circuit such as, but not limited to, one or more single-core or multi-core processors. The processor may include any combination of general-purpose and special-purpose processors, such as graphics processors, application processors. The processor may be coupled to the memory/storage and configured to execute instructions stored in the memory/storage to cause various application programs and/or an operating system to run on the system.

The baseband circuitry 720 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The processor may comprise a baseband processor. The baseband circuitry may handle various radio control functions enabling it to communicate with one or more radio networks through the radio frequency circuitry. The radio control functions may include, but are not limited to, signal modulation, encoding, decoding, radio frequency transfer, and the like. In some implementations, the baseband circuitry may provide communications compatible with one or more radio technologies. For example, in some embodiments, the baseband circuitry may support communication with evolved universal terrestrial radio access networks (evolved universal terrestrial radio access network, EUTRAN) and/or other wireless metropolitan area networks (wireless metropolitan area network, WMAN), wireless local area networks (wireless local area network, WLAN), wireless personal area networks (wireless personal area network, WPAN). An implementation in which the baseband circuitry is configured to support radio communications for more than one wireless protocol may be referred to as a multi-mode baseband circuitry.

In various embodiments, baseband circuitry 720 may include circuitry that operates with signals that are not strictly considered baseband frequencies. For example, in some embodiments, the baseband circuitry may include circuitry that operates with signals having intermediate frequencies that lie between the baseband frequency and the radio frequency. The radio frequency circuitry 710 may enable communication with a wireless network using modulated electromagnetic radiation through a non-solid medium. In various embodiments, the radio frequency circuitry may include switches, filters, amplifiers, etc. to facilitate communication with the wireless network. In various embodiments, the radio frequency circuitry 710 may include circuitry for operating signals that are not strictly considered to be at radio frequencies. For example, in some embodiments, the radio frequency circuitry may include circuitry that operates on signals having an intermediate frequency that is between the baseband frequency and the radio frequency.

In various embodiments, the transmitter circuitry, control circuitry, or receiver circuitry discussed above with respect to the user equipment, eNB, or gNB may be embodied in whole or in part in one or more of radio frequency circuitry, baseband circuitry, and/or application circuitry. As used herein, "circuitry" may refer to, be part of, or include an application specific integrated circuit (Application Specific Integrated Circuit, ASIC), an electronic circuit, a processor (shared, dedicated, or group) and/or memory (shared, dedicated, or group) that execute one or more software or firmware programs, a combinational logic circuit, and/or other suitable hardware components that provide the described functionality. In some embodiments, the electronic device circuitry may be implemented in or functions associated with one or more software or firmware modules. In some embodiments, some or all of the baseband circuitry, application circuitry, and/or the memory/storage components may be implemented together On a System On a Chip (SOC). The memory/storage 740 may be used to load and store data and/or instructions, for example, for a system. The memory/storage for one embodiment may include any combination of suitable volatile memory, such as dynamic random access memory (Dynamic random access memory, DRAM), and/or non-volatile memory, such as flash memory.

In various embodiments, I/O interface 780 may include one or more user interfaces intended to enable a user to interact with the system and/or peripheral component interfaces intended to enable peripheral components to interact with the system. The user interface may include, but is not limited to, a physical keyboard or keypad, a touchpad, a speaker, a microphone, and the like. Peripheral component interfaces may include, but are not limited to, non-volatile memory ports, universal serial bus (Universal Serial Bus, USB) ports, audio jacks, and power interfaces. In various embodiments, the sensor 770 may include one or more sensing devices to determine environmental conditions and/or location information related to the system. In some embodiments, the sensor may include, but is not limited to, a gyroscopic sensor, an accelerometer, a proximity sensor, an ambient light sensor, and a positioning unit. The positioning unit may also be part of, or interact with, baseband circuitry and/or radio frequency circuitry to communicate with components of a positioning network, such as Global Positioning System (GPS) satellites.

In various embodiments, the display 750 may include a display, such as a liquid crystal display and a touch screen display. In various embodiments, the system 700 may be a mobile computing device, such as, but not limited to, a notebook computing device, a tablet computing device, a netbook, an ultrabook, a smartphone, AR/VR glasses, and the like. In various embodiments, the system may have more or fewer components, and/or different architectures. The methods described herein may be implemented as a computer program where appropriate. The computer program may be stored on a storage medium, such as a non-transitory storage medium.

Those of ordinary skill in the art will appreciate that each of the elements, algorithms, and steps described and disclosed in the embodiments of the disclosure are implemented using electronic hardware or a combination of computer and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the particular implementation. One of ordinary skill in the art may implement the functionality of each particular application in different ways without departing from the scope of the present disclosure. It will be appreciated by those of ordinary skill in the art that, since the operation of the systems, devices and units described above are substantially identical, reference may be made to the operation of the systems, devices and units in the above embodiments. For ease of description and simplicity, these operations will not be described in detail.

It is to be understood that the disclosed systems, devices, and methods in the embodiments of the present invention may be implemented in other ways. The embodiments described are only exemplary. The division of the units mentioned is based solely on the division of the logic functions, but other manners of division are possible when implemented. It is possible that multiple units or elements are combined or integrated into another system. It is also possible that some features may be omitted or skipped. On the other hand, mutual coupling, direct coupling or communicative coupling in the above description or discussion is achieved by some ports, devices or units, whether communicating indirectly or through electronic, mechanical or other kind of means.

The units mentioned above as separate elements for explanation may be physically separate or not physically separate elements. The units mentioned above may be physical units or not, that is to say may be arranged in one place or distributed over a plurality of network units. Some or all of the units may be used according to the purpose of the embodiment. Furthermore, each functional unit in each embodiment may be integrated into one processing unit, or physically separate, or integrated into one processing unit having two or more units.

If the software functional unit is implemented and used and sold as a product, it may be stored in a readable storage medium of a computer. Based on this understanding, the technical solutions proposed by the present disclosure may be implemented substantially or partly in the form of a software product. Alternatively, part of the technical solution beneficial to the conventional technology may be implemented as a software product. The software product in the computer is stored in a storage medium, including a plurality of instructions for a computing device (e.g., a personal computer, server, or network device) to perform all or part of the steps disclosed in embodiments of the present disclosure. The storage medium includes a USB disk, a removable hard disk, a read-only memory (ROM), a random-access memory (RAM), a floppy disk, or other type of medium capable of storing program code.

While the present disclosure has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the present disclosure is not to be limited to the disclosed embodiment, but is intended to cover various arrangements included within the scope of the invention without departing from the broadest interpretation of the appended claims.

Claims (32)

1. A method of wireless communication for a User Equipment (UE), comprising:

configuring a Listen Before Talk (LBT) failure recovery procedure by the base station;

detecting a LBT failure of each Uplink (UL) bandwidth portion (BWP); a kind of electronic device with high-pressure air-conditioning system

Triggering a UL LBT failure Medium Access Control (MAC) Control Element (CE) for one or more serving cells that trigger LBT failure;

wherein the MAC CE includes a format of the UL LBT failed MAC CE, and the format of the UL LBT failed MAC CE includes a bitmap having a size equal to a maximum serving cell number of a Carrier Group (CG) and/or a bitmap having a size equal to a maximum UL BWP number of a special cell (SpCell).

2. The method of claim 1, further comprising transmitting a MAC CE to the base station, the MAC CE having serving cell information configured as a MAC CE for triggering the UL LBT failure.

3. The method of claim 2, wherein the user device cancels one or more triggered MAC CEs if the MAC CE has been transmitted on the one or more serving cells.

4. The method of claim 2, wherein the serving cell information of the MAC CE comprises at least one of:

reporting of a failed cell;

a MAC CE format configured to support an entry for indicating one or more cells announcing the LBT failure;

one or more cell indexes of the UL LBT failed MAC CE where the LBT failure occurs; or (b)

BWP related information in the MAC CE.

5. The method of claim 1, wherein the uplink transmission does not occur on one or more scells that have declared the persistent LBT failure.

6. The method of claim 1, wherein the user equipment triggers a Scheduling Request (SR) to request UL grant if no UL resources are available on one or more scells for which the persistent LBT failure has not been declared and/or on one or more special cells (spcells).

7. The method according to claim 1, wherein the format of the UL LBT failed MAC CE comprises an SCell index in which the user equipment announces the persistent LBT failure and/or a BWP index in which the user equipment announces the persistent LBT failure.

8. The method of claim 7, wherein the corresponding serving cell declares the persistent LBT failure, and wherein the corresponding bit field of the bitmap is set to 1.

9. A method of wireless communication in a base station, comprising:

configuring a Listen Before Talk (LBT) failure recovery procedure to a User Equipment (UE);

controlling the user equipment to detect LBT failure of each Uplink (UL) bandwidth part (BWP); a kind of electronic device with high-pressure air-conditioning system

Controlling the user equipment to trigger UL LBT failure Medium Access Control (MAC) Control Elements (CEs) for one or more serving cells that trigger LBT failure;

wherein the MAC CE includes a format of the UL LBT failed MAC CE, and the format of the UL LBT failed MAC CE includes a bitmap having a size equal to a maximum serving cell number of a Carrier Group (CG) and/or a bitmap having a size equal to a maximum UL BWP number of a special cell (SpCell).

10. The method of claim 9, further comprising receiving a MAC CE from the user device, the MAC CE having serving cell information configured as a MAC CE for triggering the UL LBT failure.

11. The method of claim 10, wherein the user device cancels one or more triggered MAC CEs if the MAC CE has been transmitted on the one or more serving cells.

12. The method of claim 10, wherein the serving cell information of the MAC CE comprises at least one of:

reporting of a failed cell; or (b)

A MAC CE format configured to support an entry for indicating one or more cells announcing the LBT failure;

13. the method of claim 9, wherein the uplink transmission does not occur on one or more scells that have declared the persistent LBT failure.

14. The method of claim 13, wherein the user equipment triggers a Scheduling Request (SR) to request UL grant if no UL resources are available on one or more scells for which the persistent LBT failure has not been declared and/or on one or more special cells (spcells).

15. The method according to claim 9, wherein the format of the UL LBT failed MAC CE comprises an SCell index in which the user equipment announces the persistent LBT failure and/or a BWP index in which the user equipment announces the persistent LBT failure.

16. The method of claim 15, wherein the corresponding serving cell declares the persistent LBT failure, and wherein the corresponding bit field of the bitmap is set to 1.

17. A User Equipment (UE), comprising:

a memory;

a transceiver; a kind of electronic device with high-pressure air-conditioning system

A processor coupled to the memory and the transceiver;

wherein the processor is configured by a base station with a Listen Before Talk (LBT) failure recovery procedure;

wherein the processor is configured to detect LBT failure for each Uplink (UL) bandwidth part (BWP); a kind of electronic device with high-pressure air-conditioning system

Wherein the processor is configured to trigger a UL LBT failure Medium Access Control (MAC) Control Element (CE) for one or more serving cells that trigger LBT failure;

wherein the MAC CE includes a format of the UL LBT failed MAC CE, and the format of the UL LBT failed MAC CE includes a bitmap having a size equal to a maximum serving cell number of a Carrier Group (CG) and/or a bitmap having a size equal to a maximum UL BWP number of a special cell (SpCell).

18. The user equipment of claim 17, wherein the transceiver is configured to transmit a MAC CE to the base station, the MAC CE having serving cell information configured as a MAC CE for triggering the UL LBT failure.

19. The user equipment of claim 18, wherein the processor cancels one or more triggered MAC CEs if the MAC CE has been transmitted on the one or more serving cells.

20. The user equipment of claim 18, wherein the serving cell information of the MAC CE comprises at least one of:

reporting of a failed cell;

a MAC CE format configured to support an entry for indicating one or more cells announcing the LBT failure;

one or more cell indexes of the UL LBT failed MAC CE where the LBT failure occurs; or (b)

BWP related information in the MAC CE.

21. The user equipment of claim 17, wherein the uplink transmission does not occur on one or more scells that have declared the persistent LBT failure.

22. The user equipment of claim 17, wherein the processor triggers a Scheduling Request (SR) to request UL grant if no UL resources are available on one or more scells for which the persistent LBT failure has not been declared and/or on one or more special cells (spcells).

23. The user equipment of claim 17, wherein the format of the UL LBT failed MAC CE comprises an SCell index in which the user equipment announces the persistent LBT failure and/or a BWP index in which the user equipment announces the persistent LBT failure.

24. The user equipment of claim 23, wherein the corresponding serving cell declares the persistent LBT failure, and wherein the corresponding bit field of the bitmap is set to 1.

25. A base station, comprising:

a memory;

a transceiver; a kind of electronic device with high-pressure air-conditioning system

A processor coupled to the memory and the transceiver;

wherein the processor is configured to configure a Listen Before Talk (LBT) failure recovery procedure to a User Equipment (UE);

wherein the processor is configured to control the user equipment to detect LBT failure for each Uplink (UL) bandwidth part (BWP); a kind of electronic device with high-pressure air-conditioning system

Wherein the processor is configured to control the user equipment to trigger a UL LBT failure Medium Access Control (MAC) Control Element (CE) for triggering one or more serving cells of LBT failure;

wherein the MAC CE includes a format of the UL LBT failed MAC CE, and the format of the UL LBT failed MAC CE includes a bitmap having a size equal to a maximum serving cell number of a Carrier Group (CG) and/or a bitmap having a size equal to a maximum UL BWP number of a special cell (SpCell).

26. The base station of claim 25, wherein the transceiver is configured to receive a MAC CE from the user equipment, the MAC CE having serving cell information configured as a MAC CE for triggering the UL LBT failure.

27. The base station of claim 26, wherein the user device cancels one or more triggered MAC CEs if the MAC CE has been transmitted on the one or more serving cells.

28. The base station of claim 26, wherein the serving cell information of the MAC CE comprises at least one of:

reporting of a failed cell;

a MAC CE format configured to support an entry for indicating one or more cells announcing the LBT failure;

one or more cell indexes of the UL LBT failed MAC CE where the LBT failure occurs; or (b)

BWP related information in the MAC CE.

29. The base station of claim 25, wherein the uplink transmission does not occur on one or more scells that have declared the persistent LBT failure.

30. The base station of claim 25, wherein the user equipment triggers a Scheduling Request (SR) to request UL grant if no UL resources are available on one or more scells for which the persistent LBT failure has not been declared and/or on one or more special cells (spcells).

31. The base station according to claim 25, wherein the format of the UL LBT failed MAC CE comprises an SCell index in which the user equipment announces the persistent LBT failure and/or a BWP index in which the user equipment announces the persistent LBT failure.

32. The base station of claim 31, wherein the corresponding serving cell declares the persistent LBT failure, and wherein the corresponding bit field of the bitmap is set to 1.