Report uplink listen-before-talk failure

Abstract

An exemplary embodiment relates to a user equipment (UE) that delivers an indication of one or more uplink listen-before-talk (LBT) failures to a network. The UE may identify a predetermined condition corresponding to one or more uplink listen-before-talk (LBT) failures associated with a special cell (SpCell). The UE is triggered based on the predetermined condition to provide an indication of an uplink LBT failure associated with the SpCell to the network. Next, the UE may determine a message type to be used to deliver the indication of the uplink LBT failure associated with the SpCell to the network. The UE may transmit to the network the message type including the indication of the uplink LBT failure associated with the SpCell. Subsequently, the UE may determine that the network has received the indication of the uplink LBT failure associated with the SpCell.

Description

Background Art

[0001] A user equipment (UE) may be connected to a network that supports communication in an unlicensed spectrum. When connected, the UE may utilize a listen-before-talk (LBT) procedure for uplink channel access. If one or more LBT procedures fail, the UE may report the one or more uplink LBT failures to the network. However, in a conventional scenario, the uplink resources allocated to the UE for reporting the one or more uplink LBT failures may not be large enough to accommodate information indicating the occurrence of the one or more uplink LBT failures. Summary of the Invention

[0002] According to an exemplary embodiment, a method is performed at a user equipment (UE) connected to a network. The method includes: identifying a predetermined condition corresponding to one or more uplink listen-before-talk (LBT) failures associated with a special cell (SpCell). The UE is triggered based on the predetermined condition to provide an indication of an uplink LBT failure associated with the SpCell to the network. The method further includes: determining a message type to be used for delivering the indication of the uplink LBT failure associated with the SpCell to the network; transmitting to the network the message type including the indication of the uplink LBT failure associated with the SpCell; and determining that the network has received the indication of the uplink LBT failure associated with the SpCell.

[0003] Another exemplary embodiment includes a user equipment (UE) that includes a transceiver and a processor. The transceiver is configured to communicate with a network. The processor is configured to perform operations that include: identifying a predetermined condition corresponding to one or more uplink listen-before-talk (LBT) failures associated with a special cell (SpCell). The UE is triggered based on the predetermined condition to provide an indication of an uplink LBT failure associated with the SpCell to the network. The operations further include: determining a message type to be used for delivering the indication of the uplink LBT failure associated with the SpCell to the network; transmitting to the network the message type including the indication of the uplink LBT failure associated with the SpCell; and determining that the network has received the indication of the uplink LBT failure associated with the SpCell.

[0004] Additional exemplary embodiments include an integrated circuit. The integrated circuit includes circuitry configured to identify a predetermined condition corresponding to one or more uplink listen-before-talk (LBT) failures associated with a special cell (SpCell). The UE is triggered based on the predetermined condition to provide an indication of the uplink LBT failure associated with the SpCell to the network. The integrated circuit further includes: circuitry configured to determine a message type to be used to deliver the indication of the uplink LBT failure associated with the SpCell to the network; circuitry configured to transmit to the network the message type including the indication of the uplink LBT failure associated with the SpCell; and circuitry configured to determine that the network has received the indication of the uplink LBT failure associated with the SpCell. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 An exemplary network arrangement is shown in accordance with various exemplary embodiments.

[0006] Figure 2 An exemplary UE is shown in accordance with various exemplary embodiments.

[0007] Figure 3 A method for delivering a SpCell uplink LBT failure MAC CE is shown in accordance with various exemplary embodiments.

[0008] Figure 4 A method for selecting between including a SpCell uplink LBT failure MAC CE in a RACH message or in a configured grant resource on a SpCell is shown in accordance with various exemplary embodiments.

[0009] Figure 5 A method for selecting between including a SpCell uplink LBT failure MAC CE in a RACH message or in a dynamic grant resource is shown in accordance with various exemplary embodiments. DETAILED DESCRIPTION

[0010] Exemplary embodiments may be further understood with reference to the following description and the related drawings, in which like elements are provided with the same reference numerals. Exemplary embodiments relate to a user equipment (UE) that delivers an indication of one or more uplink listen-before-talk (LBT) failures to a network.

[0011] Exemplary embodiments are described with respect to a UE. However, the reference to the UE is provided for illustrative purposes only. Exemplary embodiments may be used with any electronic component configured with hardware, software, and / or firmware for exchanging information (e.g., control information) and / or data with a network. Thus, the UE described herein is used to represent any suitable electronic device.

[0012] The UE may be configured to communicate with a network using unlicensed spectrum. To access the unlicensed spectrum, the UE may perform an LBT procedure. Those skilled in the art will understand that LBT generally refers to a mechanism for sensing whether a communication channel is idle before transmitting a signal over the communication channel. Channel sensing may include monitoring the energy levels on one or more sub-bands of the communication channel. However, the manner of performing the LBT procedure is outside the scope of the exemplary embodiments. Instead, the exemplary embodiments relate to reporting the occurrence of one or more uplink LBT failures to the network. Thus, any reference to the LBT procedure is used to denote any procedure in which the UE directly or indirectly determines whether the communication channel is available before transmitting a signal over the communication channel.

[0013] The UE may initiate an LBT procedure to transmit information and / or data to a cell of a corresponding network over an unlicensed band. However, when the UE initiates the LBT procedure, the unlicensed band may be filled with other traffic. Thus, the configured uplink communication channel may be busy and the UE cannot perform the transmission. This type of scenario may be referred to as an LBT failure. The above example is provided for illustrative purposes only. Throughout this specification, the term "LBT failure" may refer to any instance in which the UE initiates an LBT procedure but does not perform the corresponding transmission.

[0014] If the UE experiences one or more LBT failures, the UE may attempt to establish an uplink communication channel on a different bandwidth part (BWP) via a random access channel (RACH) procedure. Conventionally, the procedure for establishing an uplink communication channel on a different BWP may include reporting an indication of the one or more uplink LBT failures to the network. However, for any of a variety of different reasons, the uplink resources configured to be utilized by the UE for reporting the one or more uplink LBT failures may not be large enough to accommodate the information indicating the occurrence of the one or more uplink LBT failures.

[0015] As described above, the manner in which the LBT process is performed is beyond the scope of the exemplary embodiments. Similarly, the manner in which the UE determines to stop attempting the LBT process and / or release the corresponding uplink communication channel on a particular unlicensed frequency band is also beyond the scope of the exemplary embodiments. Instead, the exemplary embodiments relate to how the UE delivers an indication of one or more uplink LBT failures. Throughout this specification, any indexing of a particular set of circumstances that trigger the UE to report the one or more uplink LBT failures is provided for illustrative purposes only. The exemplary embodiments may apply to any suitable one or more factors that trigger the UE to deliver an indication of one or more uplink LBT failures to the network.

[0016] The exemplary embodiments are described with reference to a network being a fifth generation (5G) new radio (NR) network and the UE using a medium access control (MAC) control element (CE) to deliver an indication of one or more uplink LBT failures. Those skilled in the art will understand that the MAC CE can be used for MAC layer signaling between the UE and the cell of the network. However, any indexing of 5G NR and the MAC CE is provided for illustrative purposes only, and the exemplary embodiments may apply to any suitable network and utilize any suitable signaling mechanism.

[0017] Throughout this specification, the MAC CE may be described as being used to deliver an indication of a special cell (SpCell) uplink LBT failure. Those skilled in the art will understand that the SpCell is a type of cell used in carrier aggregation (CA) and / or multi-radio access technology dual connectivity (MRDC). Throughout this specification, MRDC generally may refer to a configuration in which the UE 110 can transmit and / or receive on multiple component carriers (CCs) corresponding to cells associated with different RATs.

[0018] In a first aspect, the exemplary embodiments will describe various mechanisms for delivering the MAC CE to the network, the MAC CE including an indication of one or more uplink LBT failures associated with the SpCell. In a second aspect, the exemplary embodiments relate to determining that the network has received the SpCell LBT failure MAC CE. However, the exemplary embodiments are not limited to delivering the SpCell uplink LBT failure MAC CE in a 5G NR network. The exemplary techniques described herein can be used in conjunction with currently implemented techniques for LBT failure reporting, future implementations of techniques for LBT failure reporting, or independently of other LBT failure reporting.

[0019] Figure 1FIG. 0 illustrates an exemplary network arrangement 100 in accordance with various exemplary embodiments. The exemplary network arrangement 100 includes a UE 110. Those skilled in the art will understand that the UE 110 can be any type of electronic component configured to communicate via a network, such as, for example, a mobile phone, a tablet computer, a desktop computer, a smart phone, a phablet, an embedded device, a wearable device, an Internet of Things (IoT) device, etc. It should also be understood that an actual network arrangement may include any number of UEs used by any number of users. Thus, for illustrative purposes, only an example with a single UE 110 is provided.

[0020] The UE 110 can be configured to communicate with one or more networks. In the example of network configuration 100, the networks with which the UE 110 can communicate wirelessly are a 5G New Radio (NR) Radio Access Network (5G NR-RAN) 120 and an LTE Radio Access Network (LTE-RAN) 122. However, it should be understood that the UE 110 can also communicate with other types of networks (e.g., traditional cellular networks, WLANs, etc.), and the UE 110 can also communicate with a network via a wired connection. Referring to the exemplary embodiments, the UE 110 can establish a connection with the 5G NR-RAN 120 and / or the LTE-RAN 122. Thus, the UE 110 can have both a 5G NR chipset for communicating with the 5G NR-RAN 120 and an LTE chipset for communicating with the LTE-RAN 122.

[0021] The 5G NR-RAN 120 and the LTE-RAN 122 can be part of cellular networks that can be deployed by cellular providers (e.g., Verizon, AT&T, Sprint, T-Mobile, etc.). These networks 120 and 122 can include, for example, cells or base stations (Node B, eNodeB, HeNB, eNB, gNB, gNodeB, macro cell base stations, micro cell base stations, small cell base stations, femto cell base stations, etc.) configured to send and receive traffic from UEs equipped with appropriate cellular chipsets.

[0022] As described above, the exemplary embodiments relate to CA and MRDC. Thus, in some embodiments, the UE 110 may be connected to both the 5G NR-RAN 120 and the LTE-RAN 122. However, the reference to the separate 5G NR-RAN 120 and LTE-RAN 122 is provided only for illustrative purposes. The actual network arrangement may include a radio access network that includes an architecture capable of providing both 5G NR RAT and LTE RAT services. For example, a next-generation radio access network (NG-RAN) (not shown) may include next-generation Node Bs (gNBs) that provide 5G NR services and next-generation evolved Node Bs (ng-eNBs) that provide LTE services. The NG-RAN may be connected to at least one of an evolved packet core (EPC) or a 5G core (5GC). Thus, in one exemplary configuration, the UE 110 may achieve MRDC by establishing connections to at least one cell corresponding to the 5G NR-RAN 120 and at least one cell corresponding to the LTE-RAN 122. In another exemplary configuration, the UE 110 may achieve MRDC by establishing connections to at least two cells corresponding to the NG-RAN or other types of similar RANs. Thus, the examples of the separate 5G NR-RAN 120 and LTE-RAN 122 are provided only for illustrative purposes.

[0023] Returning to the exemplary network arrangement 100, the UE 110 may be connected to the 5G NR-RAN 120 via at least one of the next-generation Node Bs (gNBs) 120A or gNB 120B. The UE 110 may be connected to the LTE-RAN 122 via at least one of the evolved Node Bs (eNBs) 122A or eNB 122B. Those skilled in the art will understand that any relevant processes for connecting the UE 110 to the 5G NR-RAN 120 or the LTE-RAN 122 may be performed. For example, as described above, the 5G NR-RAN 120 may be associated with a particular cellular provider at which the UE 110 and / or its user have protocol and credential information (e.g., stored on a SIM card). Upon detecting the presence of the 5G NR-RAN 120, the UE 110 may transmit the corresponding credential information in order to associate with the 5G NR-RAN 120. More specifically, the UE 110 may be associated with a particular cell (e.g., gNB 120A of the 5G NR-RAN 120). Similarly, in order to access LTE services, the UE 110 may be associated with the eNB 122A. However, as described above, the references to the 5G NR-RAN 120 and the LTE-RAN 122 are for illustrative purposes only, and any suitable type of RAN may be used.

[0024] In addition to RANs 120 and 122, network arrangement 100 further includes a cellular core network 130, the Internet 140, an IP Multimedia Subsystem (IMS) 150, and a network service backbone 160. The cellular core network 130 can be regarded as an interconnected set of components that manage the operations and traffic of a cellular network and can include an EPC and / or a 5GC. The cellular core network 130 also manages the traffic flowing between the cellular network and the Internet 140. The IMS 150 can generally be described as an architecture for delivering multimedia services to the UE 110 using IP protocols. The IMS 150 can communicate with the cellular core network 130 and the Internet 140 to provide multimedia services to the UE 110. The network service backbone 160 communicates directly or indirectly with the Internet 140 and the cellular core network 130. The network service backbone 160 can generally be described as a set of components (e.g., servers, network storage arrangements, etc.) that implement a set of services that can be used to extend the functions for the UE 110 to communicate with various networks.

[0025] Figure 2 An exemplary UE 110 is shown in accordance with various exemplary embodiments. The UE 110 will be described with reference to Figure 1 network arrangement 100. The UE 110 can represent any electronic device and can include a processor 205, a memory arrangement 210, a display device 215, an input / output (I / O) device 220, a transceiver 225, and other components 230. The other components 230 can include, for example, an audio input device, an audio output device, a battery, a data acquisition device, a port for electrically connecting the UE 110 to other electronic devices, a sensor for detecting the condition of the UE 110, etc.

[0026] The processor 205 can be configured to execute multiple engines of the UE 110. For example, the engines can include an LBT failure reporting engine 235. The LBT failure reporting engine 235 can be configured with various different mechanisms for delivering the SpCell uplink LBT failure MAC CE to the network. In a first aspect, when certain conditions exist, the LBT failure reporting engine 235 can trigger a specific exemplary mechanism. In a second aspect, when certain indications are recognized, the LBT failure reporting engine 235 can determine that the network has received the SpCell uplink LBT failure MAC CE.

[0027] The above engines, each as an application program (e.g., a program) executed by the processor 205, are merely exemplary. The functions associated with the engines can also be represented as separate integrated components of the UE 110 or can be modular components coupled to the UE 110, e.g., integrated circuits with or without firmware. For example, an integrated circuit can include an input circuit for receiving signals and a processing circuit for processing signals and other information. The engines can also be embodied as one application program or separate multiple application programs. Additionally, in some UEs, the functionality described for the processor 205 is shared between two or more processors such as a baseband processor and an application processor. The exemplary embodiments can be implemented in any of these or other configurations of the UE.

[0028] The memory 210 can be a hardware component configured to store data related to operations performed by the UE 110. The display device 215 can be a hardware component configured to display data to the user, while the I / O device 220 can be a hardware component that enables the user to make inputs. The display device 215 and the I / O device 220 can be separate components or can be integrated together (such as a touch screen). The transceiver 225 can be a hardware component configured to establish connections with the LTE-RAN 120, 5G NR-RAN 122, etc. Thus, the transceiver 225 can operate on multiple different frequencies or channels (e.g., a set of contiguous frequencies).

[0029] As described above, the exemplary embodiments relate to the UE 110 delivering a SpCell uplink LBT failure MAC CE to the network. The UE 110 can interact with the SpCell in the context of CA and / or MRDC. To provide a general example of the context in which the UE 110 and the SpCell can interact, various aspects of CA and / or MRDC will be described in more detail below. However, any reference to a particular type of RAT, core network, cell, or operating mode is for illustrative purposes only. The exemplary embodiments can be applicable to any scenario in which the UE 110 is to deliver an indication of one or more uplink LBT failures to the network.

[0030] The UE 110 may be configured to access 5G NR services when operating in the non-standalone (NSA) mode of 5G or the standalone (SA) mode of 5G. In the NSA mode, the UE 110 may establish connections with both the 5G NR RAT and the LTE RAT (e.g., MRDC). For example, when in the NSA mode of 5G, the UE 110 may implement MRDC via a secondary cell group (SCG) corresponding to the 5G NR and a secondary cell group (SCG) corresponding to LTE, and vice versa. Each cell group may include at least one cell for the corresponding RAT. In an exemplary scenario of MRDC, from the perspective of the protocol stack, the UE 110 may have a control plane and a user plane using the 5G NR network, while also having a control plane and a user plane using the LTE network. In another exemplary scenario of MRDC, the UE 110 may have a control plane using the LTE network and a user plane using the 5G NR network, and vice versa. Therefore, when operating in the NSA mode of 5G, the UE 110 may be connected to both 5G NR and LTE (e.g., MRDC) simultaneously. However, it should be noted that when operating in the NSA mode of 5G, the UE 110 may switch between instances connected to one RAT (e.g., 5G NR, LTE, legacy, etc.) and instances connected to multiple RATs (e.g., MRDC).

[0031] In the SA mode of 5G, the UE 110 may be connected to one RAT at a specific time. Therefore, when deployed, the network connection may switch between different RATs (e.g., 5G NR, LTE, legacy, etc.). For example, at a first time, the network connection may use the 5GC, and the UE 110 may communicate with the network via at least one NR cell (e.g., gNB 120A, gNB 120B). During operation, the UE 110 may experience a handover from 5G to LTE, where the network connection may then use the EPC, and the UE 110 may communicate with the network via at least one LTE cell (e.g., eNB 122A, eNB 122B).

[0032] The UE 110 may also be configured with a carrier aggregation (CA) function. Both CA and MRDC involve the UE 110 being configured with multiple component carriers (CCs). Each CC may represent a channel that facilitates communication between the UE 110 and the network over a specific frequency band. Therefore, in order to utilize CA or MRDC, the UE 110 may communicate with the network using multiple CCs corresponding to multiple cells.

[0033] CA may include a Primary Component Carrier (PCC) and at least one Secondary Component Carrier (SCC), where the PCC and the at least one SCC correspond to the same RAT used to facilitate communication with the network. The PCC may be partially used for control information such as scheduling requests, uplink grants, downlink grants, etc. The CA function enables the PCC and at least one SCC to combine bandwidths to exchange data with UE 110. Thus, with CA, the PCC may provide a first portion of the total bandwidth for the data to be exchanged, while the SCC may provide a second portion of the total bandwidth. To further increase the total available bandwidth for the data to be exchanged with UE 110, additional SCCs may be incorporated.

[0034] In the SA mode of 5G, UE 110 may be configured with the CA function. In the NSA mode, the UE may be configured with both MRDC and CA simultaneously. That is, the MCG may provide one or more CCs corresponding to the first RAT, and the SCG may provide one or more aggregated CCs corresponding to the second RAT.

[0035] In CA, the Primary Cell (PCell) may provide the PCC on one frequency band, and one or more Secondary Cells (SCells) may provide the SCCs allocated to other frequency bands. For example, in the exemplary network arrangement 100, the PCell may be gNB 120A, and the SCell may be gNB 120B, and vice versa. Generally speaking, the PCell refers to the cell that performs control procedures and provides Radio Resource Control (RRC) connection. In MRDC, independent of the PCell, the Primary Secondary Cell (PSCell) may also perform control procedures. The PCell may correspond to the MCG, and the PSCell may correspond to the SCG.

[0036] Those skilled in the art will understand that in the context of CA, the term "SpCell" may refer to the PCell. It should also be understood that in the context of MRDC, the term "SpCell" may refer to the PCell of the MCG or the PSCell of the SCG. Generally speaking, the SpCell refers to the cell that supports the Physical Uplink Control Channel (PUCCH) and / or the contention-based random access procedure.

[0037] The above descriptions of the SA mode and the NSA mode are not intended to limit the exemplary embodiments in any way. On the contrary, the above descriptions of the SA mode and the NSA mode are only intended to provide a general example of the context in which UE 110 and the exemplary SpCell may interact.

[0038] The SpCell can operate in unlicensed spectrum. Thus, for uplink communication to the SpCell, the UE 110 can utilize the LBT procedure. If one or more LBT failures occur in the case of the currently pre-empted SpCell, the UE 110 can be triggered to report the one or more uplink LBT failures to the network. In a first aspect, an exemplary implementation relates to delivering a MAC CE to the network, the MAC CE including an indication of one or more uplink LBT failures associated with the SpCell. In a second aspect, an exemplary implementation relates to determining that the network has received the SpCell LBT failure MAC CE.

[0039] Figure 3 Method 300 for delivering a SpCell uplink LBT failure MAC CE according to various exemplary implementations is shown. Method 300 will be described with reference to Figure 2 the UE 110 and Figure 1 the network arrangement 100.

[0040] First, consider the following exemplary scenario. The UE 110 is pre-empted on the gNB 120A of the 5G NR-RAN 120. In this scenario, the gNB 120A is a SpCell operating in unlicensed spectrum. The UE 110 is configured to perform the LBT procedure for uplink transmission to the gNB 120A. In some implementations, the UE 110 can be configured with CA and / or MRDC. Thus, the UE 110 can also be configured to communicate with other cells in the uplink and / or downlink (e.g., gNB 120B, eNB 122A, eNB 122B).

[0041] In 305, the UE 110 identifies a predetermined condition corresponding to one or more uplink LBT failures associated with the SpCell. The occurrence of the predetermined condition can indicate to the UE 110 that the BWP traffic currently utilized by the UE 110 for uplink transmission to the SpCell is overly congested and cannot serve as a viable communication channel for uplink transmission to the SpCell. As will be described below, the predetermined condition can trigger the UE 110 to switch to a different BWP and provide the network with an indication of the one or more uplink LBT failures associated with the SpCell (e.g., a SpCell uplink LBT failure MAC CE). In some implementations, the BWP switch and the delivery of the indication of the one or more uplink LBT failures associated with the SpCell can occur during the same procedure. In other implementations, the BWP switch and the delivery of the indication of the one or more uplink LBT failures associated with the SpCell can occur in different procedures.

[0042] The predetermined condition may include one or more instances of uplink LBT failure. For example, UE 110 may utilize a counter and a timer to track the occurrence of uplink LBT failure associated with the SpCell. When the first LBT failure occurs, UE 110 may start the timer and set the counter to one. If the timer expires before another LBT failure occurs, the counter is reset to zero. If another LBT failure occurs before the timer expires, the timer is reset and the counter is set to two. In this example, when the counter exceeds a threshold, the predetermined condition has occurred. Some entities may refer to this concept as consistent LBT failure. However, the above example is not intended to limit the exemplary embodiments in any way. As described above, any indexing of a particular set of circumstances that triggers the UE to report the one or more uplink LBT failures is provided for illustrative purposes only. The exemplary embodiments may apply to any suitable one or more factors that trigger the UE to deliver an indication of the one or more uplink LBT failures to the network.

[0043] In 310, UE 110 switches to a different BWP for uplink channel access. For example, if UE 110 is initially configured to utilize BWP(X) for uplink communication with the SpCell, UE 110 may switch to BWP(Y) in response to identifying the predetermined condition in 305. Switching to a different BWP may include performing a RACH procedure. As will be described in more detail below, in some embodiments, the SpCell uplink LBT failure MAC CE may be delivered by UE 110 to the network during the RACH procedure. In other embodiments, the SpCell uplink LBT failure MAC CE may be delivered by UE 110 to the network outside of the RACH procedure.

[0044] In 315, UE 110 selects a SpCell uplink LBT failure MAC CE delivery mechanism. For example, the SpCell uplink LBT failure MAC CE may be provided to the network in any one of a variety of different messages transmitted by UE 110 to the network (e.g., SpCell, PCell, SCell, etc.). In this example, UE 110 may select one of the following messages based on any suitable selection criteria. However, the exemplary embodiments are not limited to the messages or selection criteria described below and may apply to selecting between any suitable set of one or more messages using any suitable selection criteria.

[0045] Accordingly, an exemplary embodiment relates to a scenario where the UE 110 is performing two different procedures, such as i) BWP switching and ii) SpCell uplink LBT failure MAC CE delivery. Although the UE 110 may optionally select the message for SpCell uplink LBT failure MAC CE delivery that is included in the RACH procedure, these two procedures are performed independently of each other and do not need to occur in any particular time sequence.

[0046] An exemplary SpCell uplink LBT failure MAC CE delivery mechanism may involve a message that is included in the RACH procedure. For example, the SpCell uplink LBT failure MAC CE may be included in message 3 (Msg3) of the four-step RACH procedure. The four-step RACH procedure may include the UE 110 transmitting a RACH preamble to the network. Those skilled in the art will understand the type of information that may be included in the RACH preamble. In response, the network may transmit a random access response (RAR) that is transmitted to the UE 110. The RAR may include an uplink grant for the UE 110. According to the uplink grant, the UE 110 may then transmit MSG3 to the network. In some embodiments, the SpCell uplink LBT failure MAC CE may be included in this message. Those skilled in the art will understand other types of information that may be included in MSG3. In the fourth step, the network may transmit a contention resolution message indicating that the UE 110 and the network are synchronized on this BWP.

[0047] As another example, the SpCell uplink LBT failure MAC CE may be included in message A (MSGA) of the two-step RACH procedure. Those skilled in the art will understand that the two-step RACH procedure includes a first transmission from the UE 110 to the network. This first step may be the UE 110 transmitting MSGA to the network, and the MSGA may include information similar to the above-mentioned RACH preamble and MSG3. In some embodiments, the SpCell uplink LBT failure MAC CE may be included in this message. The second step may be the network transmitting message B (MSGB) to the UE 110, and the MSGB may include information similar to the above-mentioned RAR and contention resolution message.

[0048] Another exemplary SpCell uplink LBT failure MAC CE delivery mechanism may involve utilizing configured grants. Those skilled in the art will understand that configured grants involve the concept of grant-free scheduling. For example, a cell may reserve resources for uplink transmissions, and UE 110 may be aware of these reserved resources. To perform an uplink transmission, UE 110 may utilize one of the reserved resources without sending a scheduling request and waiting for a subsequent grant message from the cell. Configured grants provide low latency and may be utilized in use cases such as ultra-reliable low-latency communication (URLLC).

[0049] Throughout this specification, "configured grant resources" may refer to resources that are pre-allocated to UE 110 without UE 110 providing an explicit request for the resources used to perform the corresponding uplink transmission. As will be described below, in some embodiments, UE 110 may utilize configured grant resources on different BWPs (e.g., BWP(Y)) to deliver SpCell uplink LBT failure MAC CE. In other embodiments, UE 110 may utilize configured grant resources on different cells to deliver SpCell uplink LBT failure MAC CE.

[0050] Figure 4 A method 400 for selecting between including a SpCell uplink LBT failure MAC CE in a RACH message or in configured grant resources on a SpCell is shown according to various exemplary embodiments. Method 400 will be described with reference to Figure 3 method 300 of Figure 2 UE 110 of Figure 1 and network arrangement 100 of

[0051] In 405, UE 110 initiates a RACH procedure to synchronize with the network. As noted above in 310, the RACH procedure may be performed to switch from a first BWP (e.g., BWP(X)) to a different second BWP (e.g., BWP(Y)).

[0052] At 410, the UE 110 determines whether the RACH uplink resource can accommodate the SpCell uplink failure MAC CE. The size of the uplink resource and the information to be provided to the network during the RACH procedure can vary. Thus, in some scenarios, there may not be enough space to fit the SpCell uplink failure MAC CE in the RACH uplink resource. Accordingly, the UE 110 may utilize the configured grant resource on the SpCell to deliver the SpCell uplink LBT failure MAC CE instead of the RACH resource. However, the exemplary embodiments are not limited to the selection criteria including the size of the RACH uplink resource, and can select between the RACH uplink resource and the configured grant resource on the SpCell based on any suitable one or more factors.

[0053] To provide an example, in the context of a four-step RACH procedure, the UE 110 may receive an uplink grant in the RAR. The UE 110 is configured to use the uplink grant to transmit MSG 3 to the network. However, for any of a variety of different reasons, the uplink grant resource for MSG3 may not be able to accommodate the SpCell uplink failure MAC CE. Similarly, in the context of a two-step RACH procedure, the uplink grant resource for MSGA may not be able to accommodate the SpCell uplink failure MAC CE.

[0054] If the RACH uplink resource can accommodate the SpCell uplink failure MAC CE, method 400 may proceed to 415. At 415, as part of the RACH procedure, the UE 110 transmits the SpCell uplink failure MAC CE to the network.

[0055] If the RACH uplink resource cannot accommodate the SpCell uplink failure MAC CE, method 400 may proceed to 420. At 420, the UE 110 uses the configured grant resource on the SpCell to transmit the SpCell uplink failure MAC CE to the network. For example, after the UE 110 completes the RACH procedure, the configured grant type 1 may be available on the BWP(Y) of the SpCell. Thus, the RACH procedure can be completed before delivering the SpCell uplink failure MAC CE on the configured grant resource. Subsequently, method 400 ends.

[0056] Method 400 describes a scenario in which UE 110 can utilize the configured grant resources on the SpCell. However, if the configured grant resources are available on the SCell, UE 110 can transmit the SpCell uplink LBT failure MAC CE to the network via the configured grant resources corresponding to the SCell. This type of scenario can be applicable to CA or MRDC. In this example, since UE 110 utilizes the configured grant resources on the SCell, UE 110 does not have to wait for the RACH procedure using the SpCell to complete to transmit the SpCell uplink LBT failure MAC CE to the network.

[0057] Returning to method 300, another exemplary SpCell uplink LBT failure MAC CE delivery mechanism can involve utilizing dynamic grants. Dynamic grant resources can be allocated to UE 110 based on a service request (SR) transmitted from UE 110 to the serving cell. Thus, compared to configured grants, dynamic grants utilize an explicit signaling request.

[0058] Throughout this specification, "dynamic grant resources" can refer to resources that are allocated in response to a scheduling request (SR) or other similar type of indication. As will be described below, in some embodiments, UE 110 can utilize the dynamic grant resources on the SpCell to deliver the SpCell uplink LBT failure MAC CE. In other embodiments, UE 110 can utilize the dynamic grant resources on a different cell (e.g., SCell) to deliver the SpCell uplink LBT failure MAC CE.

[0059] Figure 5 Method 500 for selecting between including the SpCell uplink LBT failure MAC CE in a RACH message or in dynamic grant resources is shown. Method 500 will be described with reference to Figure 3 method 300 of Figure 2 UE 110 of Figure 1 and network arrangement 100 of

[0060] In 505, UE 110 initiates a RACH procedure to synchronize with the network. This is substantially similar to 405 of method 400.

[0061] At 510, the UE 110 determines whether a predetermined condition is met. The predetermined condition may indicate to the UE 110 whether a RACH message or a dynamic grant is to be used to deliver the SpCell uplink LBT failure MAC CE. Similar to 410 of method 400, the predetermined condition at 510 may consider whether the RACH uplink resource (e.g., the uplink grant included in the RAR) can accommodate the SpCell uplink failure MAC CE. The predetermined condition may also consider whether a dynamic grant on a different cell (e.g., SCell) has been received previously. However, the exemplary embodiments are not limited to the selection criteria including the size of the RACH uplink resource and whether a dynamic grant on a different cell has been received previously. The exemplary embodiments may select between the RACH uplink resource and the dynamic grant resource on the SpCell based on any suitable one or more factors.

[0062] If the RACH uplink resource can accommodate the SpCell uplink failure MAC CE and a dynamic grant on a different cell has not been received previously, method 500 proceeds to 515. At 515, as part of the RACH procedure, the UE 110 transmits the SpCell uplink failure MAC CE to the network.

[0063] If the RACH uplink resource cannot accommodate the SpCell uplink failure MAC CE and / or a dynamic grant resource on a different cell has been received previously, method 500 proceeds to 520. At 520, the UE 110 transmits an SR to the SpCell. For example, after the RACH procedure is completed and the UE 110 is synchronized with the network on a different BWP (Y), the UE 110 may transmit an SR to the SpCell to request an uplink grant for the dynamic grant resource.

[0064] At 525, the UE 110 receives an uplink grant in response to the scheduling request. At 530, the UE 110 uses the dynamic grant resource indicated in the uplink grant to transmit the SpCell uplink LBT failure MAC CE to the SpCell. Subsequently, method 500 ends.

[0065] Method 500 describes a scenario in which UE 110 can utilize dynamic grant resources on the SpCell. However, as pointed out above, if dynamic grant resources are available on the SCell, UE 110 can utilize the dynamic grant resources on the SCell to deliver the SpCell uplink LBT failure MAC CE to the network. This type of scenario can be applicable to CA or MRDC. In this example, since UE 110 utilizes the dynamic grant resources on the SCell, UE 110 does not have to wait for the RACH procedure using the SpCell to complete to transmit the SpCell uplink LBT failure MAC CE to the network.

[0066] Returning to method 300, after UE 110 selects the SpCell uplink LBT failure MAC CE delivery mechanism, method 300 proceeds to 320. At 320, UE 110 determines that the SpCell uplink LBT failure MAC CE has been successfully delivered.

[0067] In one embodiment, successful delivery can be assumed based on the RACH procedure. For example, consider a scenario in which UE 110 transmits the SpCell uplink LBT failure MAC CE to the network in MSG3 of the RACH procedure. MSG3 may also include a cell radio network temporary identifier (C-RNTI) used by the cell to distinguish between connected UEs. If MSG4 resolves UE 110 using the C-RNTI, UE 110 can assume that MSG3 has been successfully received, and thus, can consider that the SpCell uplink LBT failure MAC CE has been successfully received.

[0068] In another embodiment, successful delivery can be assumed based on a hybrid automatic repeat request (HARQ) acknowledgement (ACK). For example, consider a scenario in which UE 110 transmits the SpCell uplink LBT failure MAC CE to the network in a configured grant resource. When using a configured grant, UE 110 can be configured to receive an ACK / negative acknowledgement (NACK) via downlink feedback information (DFI). Therefore, if UE 110 receives an ACK indicating successful reception information transmitted via the configured grant resource, UE 110 can assume that the SpCell uplink LBT failure MAC CE has been successfully received.

[0069] In another embodiment, successful delivery may be assumed based on a timer. For example, consider a scenario where UE 110 transmits a SpCell uplink LBT failure MAC CE to the network in a dynamic grant resource. When the SpCell uplink LBT failure MAC CE is transmitted on the dynamic grant resource, UE 110 may start a timer. If UE 110 receives downlink control information (DCI) scheduling a retransmission on a PUSCH having the same HARQ process ID as the SpCell uplink LBT failure MAC CE, the timer may be configured to be reset. That is, if in response to a PUSCH transmission on the dynamic resource including the SpCell uplink LBT failure MACE CE, UE 110 receives DCI scheduling a retransmission, UE 110 may assume that the SpCell uplink LBT failure MACE CE has not been successfully received. If the timer expires, UE 110 may assume that the network has successfully received the SpCell uplink LBT failure MAC CE since no retransmission is scheduled. Subsequently, method 300 ends. However, the above example is provided for illustrative purposes only, and the exemplary embodiment is not limited to the above indication and may assume that the network has successfully received the SpCell uplink failure MAC CE based on any suitable indication.

[0070] Methods 300 to 500 describe the SpCell uplink LBT failure MAC CE delivery process, which is independent of but may consider aspects of the RACH process performed for BWP switching. However, considering the RACH process may introduce latency into the delivery of an indication of one or more uplink LBT failures. To avoid the latency that may be caused by the RACH process, UE 110 may alternatively indicate BWP switching via a SCell. For example, if UE 110 is configured with a SCell supporting uplink communication, UE 110 is able to use a BWP switching MAC CE instead of the RACH process to indicate BWP switching to the SCell. The content of the BWP switching MAC CE may include, but is not limited to, the identified local channel (LCID), the cell ID of the cell representing the BWP, the target BWP ID representing the BWP to which UE 110 switches, etc. If UE 110 receives an uplink grant scheduling a new transmission for the same HARQ process as the PUSCH carrying the BWP switching MAC CE, UE 110 may assume that the indication of BWP switching has been successfully received and the network is aware of the BWP switching.

[0071] Those skilled in the art will understand that the above-described exemplary embodiments can be implemented with any suitable software configuration or hardware configuration or a combination thereof. Exemplary hardware platforms for implementing the exemplary embodiments may include, for example, Intel x86-based platforms with compatible operating systems, Windows OS, Mac platforms and MAC OS, mobile devices with operating systems such as iOS, Android, etc. In other examples, the exemplary embodiments of the above methods may be embodied as a program including lines of code stored on a non-transitory computer-readable storage medium, which, when compiled, can be executed on a processor or microprocessor.

[0072] Although this patent application describes various combinations of various embodiments each having different features, those skilled in the art will understand that any feature of one embodiment can be combined with the features of other embodiments in any manner not negated by the disclosure or features that are not functionally or logically inconsistent with the operation of the devices of the embodiments disclosed in the present invention or the said functions.

[0073] It is well known that the use of personally identifiable information should follow privacy policies and practices that are recognized as meeting or exceeding industry or government requirements for maintaining user privacy. Specifically, personally identifiable information data should be managed and processed to minimize the risk of inadvertent or unauthorized access or use, and the nature of the authorized use should be clearly explained to the user.

[0074] It will be apparent to those skilled in the art that various modifications can be made to the present disclosure without departing from the essence or scope of the present disclosure. Accordingly, the present disclosure is intended to cover modifications and variations of the present disclosure provided that these modifications and variations are within the scope of the appended claims and their equivalents.

Claims

1. A method performed at a user equipment UE connected to a network, comprising: Identifying a predetermined condition corresponding to one or more uplink listen-before-talk LBT failures associated with a special cell SpCell, wherein the UE is triggered based on the predetermined condition to provide an indication of an uplink LBT failure associated with the SpCell to the network; Determining a message type to be used for delivering the indication of the uplink LBT failure associated with the SpCell to the network, wherein the message type is an indication of a bandwidth part BWP switch performed by the UE to be transmitted to a secondary cell SCell; Transmitting to the network the message type including the indication of the uplink LBT failure associated with the SpCell; And Determining that the network has received the indication of the uplink LBT failure associated with the SpCell.

2. The method according to claim 1, wherein determining the message type comprises: Determining whether an uplink grant received during a random access channel RACH procedure with the SpCell can accommodate the indication of the uplink LBT failure associated with the SpCell.

3. The method according to claim 2, further comprising: When the uplink grant received during the RACH procedure can accommodate the indication of the uplink LBT failure associated with the SpCell, transmitting, during the RACH procedure, the indication of the uplink LBT failure associated with the SpCell to the SpCell, wherein the message type is message 3 (MSG3).

4. The method according to claim 2, further comprising: When the uplink grant received during the RACH procedure cannot accommodate the indication of the uplink LBT failure associated with the SpCell, transmitting the indication of the uplink LBT failure associated with the SpCell on a configured grant resource allocated by the SpCell.

5. The method according to claim 4, wherein transmitting the indication of the uplink LBT failure associated with the SpCell is performed after the RACH procedure is completed.

6. The method according to claim 2, further comprising: When the uplink grant received during the RACH procedure cannot accommodate the indication of the uplink LBT failure associated with the SpCell, transmitting the indication of the uplink LBT failure associated with the SpCell on a dynamic grant resource allocated by the SpCell.

7. The method according to claim 1, wherein determining the message type comprises: Determining whether the UE has been allocated a dynamic grant resource by a secondary cell SCell, and when the UE has been allocated the dynamic grant resource by the SCell, transmitting the indication of the uplink LBT failure associated with the SpCell to the SCell on the dynamic grant resource allocated by the SCell.

8. The method according to claim 1, wherein determining that the network has received the indication is based on receiving an uplink grant for scheduling a new transmission for a Hybrid Automatic Repeat reQuest (HARQ) process.

9. The method according to claim 1, wherein determining that the network has received the indication is based on one of the following: i) a Cell Radio Network Temporary Identifier (C-RNTI) corresponding to the UE included in Message 4 (MSG4) of a Random Access Channel (RACH) process, ii) receiving a Hybrid Automatic Repeat reQuest (HARQ) Acknowledgement (ACK) via Downlink Feedback Information (DFI), or iii) expiration of a timer initiated with respect to transmission of the indication of the uplink LBT failure.

10. A User Equipment (UE) comprising: a transceiver configured to communicate with a network; and a processor configured to perform operations, the operations including: identifying a predetermined condition corresponding to one or more uplink Listen Before Talk (LBT) failures associated with a Special Cell (SpCell), wherein the UE is triggered based on the predetermined condition to provide an indication of the uplink LBT failure associated with the SpCell to the network; determining a message type to be used for delivering the indication of the uplink LBT failure associated with the SpCell to the network, wherein the message type is an indication of a Bandwidth Part (BWP) switch performed by the UE to be transmitted to a Secondary Cell (SCell); transmitting to the network the message type including the indication of the uplink LBT failure associated with the SpCell; and determining that the network has received the indication of the uplink LBT failure associated with the SpCell.

11. The UE according to claim 10, wherein determining the message type comprises: Determining whether an uplink grant received during a Random Access Channel (RACH) process with the SpCell can accommodate the indication of the uplink LBT failure associated with the SpCell, and when the uplink grant received during the RACH process cannot accommodate the indication of the uplink LBT failure associated with the SpCell, transmitting the indication of the uplink LBT failure associated with the SpCell on a configured grant resource allocated by the SpCell.

12. The UE according to claim 10, wherein determining the message type comprises: Determining whether an uplink grant received during a Random Access Channel (RACH) process with the SpCell can accommodate the indication of the uplink LBT failure associated with the SpCell, and when the uplink grant received during the RACH process cannot accommodate the indication of the uplink LBT failure associated with the SpCell, transmitting the indication of the uplink LBT failure associated with the SpCell on a dynamic grant resource allocated by the SpCell.

13. The UE according to claim 10, wherein determining the message type comprises: Determine whether the UE has been allocated dynamic grant resources by a secondary cell (SCell), and when the UE has been allocated the dynamic grant resources by the SCell, transmit the indication of the uplink Listen-Before-Talk (LBT) failure associated with the special cell (SpCell) on the dynamic grant resources allocated by the SCell.

14. The UE according to claim 10, wherein determining that the network has received the indication is based on one of the following: i) the cell radio network temporary identifier (C-RNTI) corresponding to the UE included in message 4 (MSG4) of a random access channel (RACH) procedure, or ii) receiving a hybrid automatic repeat request (HARQ) acknowledgement (ACK) via downlink feedback information (DFI).

15. An integrated circuit, comprising: a circuit configured to identify a predetermined condition corresponding to one or more uplink Listen-Before-Talk (LBT) failures associated with a special cell (SpCell), wherein a user equipment (UE) is triggered based on the predetermined condition to provide an indication of an uplink LBT failure associated with the SpCell to the network; a circuit configured to determine a message type to be used for delivering the indication of the uplink LBT failure associated with the SpCell to the network, wherein the message type is an indication of a bandwidth part (BWP) switch performed by the UE to be transmitted to a secondary cell (SCell); a circuit configured to transmit to the network the message type including the indication of the uplink LBT failure associated with the SpCell; and a circuit configured to determine that the network has received the indication of the uplink LBT failure associated with the SpCell.

16. The integrated circuit according to claim 15, wherein determining the message type includes: Determine whether the uplink grant received during a random access channel (RACH) procedure with the SpCell can accommodate the indication of the uplink LBT failure associated with the SpCell, and when the uplink grant received during the RACH procedure cannot accommodate the indication of the uplink LBT failure associated with the SpCell, transmit the indication of the uplink LBT failure associated with the SpCell on the configured grant resources allocated by the SpCell.

17. The integrated circuit according to claim 15, wherein determining the message type comprises: Determine whether the uplink grant received during a random access channel (RACH) procedure with the SpCell can accommodate the indication of the uplink LBT failure associated with the SpCell, and when the uplink grant received during the RACH procedure cannot accommodate the indication of the uplink LBT failure associated with the SpCell, transmit the indication of the uplink LBT failure associated with the SpCell on the dynamic grant resources allocated by the SpCell.

18. The integrated circuit according to claim 15, wherein determining the message type includes: Determine whether dynamic grant resources have been allocated by a secondary cell (SCell), and when the dynamic grant resources have been allocated by the SCell, transmit the indication of the uplink LBT failure associated with the SpCell on the dynamic grant resources allocated by the SCell.

19. The integrated circuit according to claim 15, wherein determining that the network has received the indication is based on the expiration of a timer initiated with respect to the transmission of the indication of the uplink LBT failure.

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