Patent Description:
The subject matter disclosed herein relates generally to wireless communications and more particularly relates to directional listen-before-talk ("LBT") procedures, especially for autonomous uplink communications using unlicensed spectrum. There is disclosed herein a method at a user equipment and a user equipment.

In certain wireless communication systems, service is supplemented by operation on unlicensed spectrum. However, operation on unlicensed spectrum requires Clear Channel Assessment ("CCA") prior to transmission, for example involving a LBT procedure.

In NR-U, channel access in both downlink and uplink relies on the CCA (e.g., LBT procedure) to gain channel access. Prior to any transmission, the gNB and/or UE must first sense the channel to find out whether there are ongoing communications on the channel. No beamforming is considered for LBT in NR-U in Rel. <NUM> and only omni-directional LBT is assumed.

<CIT> describes a wireless device that increments a listen before talk counter based on a listen before talk procedure indicating a busy channel for an uplink transmission via a first bandwidth part. Based on the listen before talk counter reaching a first value, an active bandwidth part is switched from the first bandwidth part to a second bandwidth part.

<CIT> describes a wireless device performing a random access procedure may select two or more random access resource occasions based on received downlink reference signals. Using a listen before talk procedure, the wireless device may select a first available random access resource occasion from the two or more random access resource occasions that are determined to be clear.

Claim <NUM> defines a method at a user equipment and claim <NUM> defines a user equipment. In the following, any method and/or apparatus referred to as embodiments but nevertheless do not fall within the scope of the appended claims are to be understood as examples helpful in understanding the invention.

Disclosed are procedures for beam switching after LBT procedure. Said procedures may be implemented by apparatus, systems, methods, or computer program products.

One method of a User Equipment device ("UE") includes performing a Listen-Before-Talk ("LBT") procedure prior to a first occasion of configured-grant ("CG") resources and performing uplink ("UL") transmission of a first transport block ("TB") during the first occasion and using a first beam in response to successful LBT. The method includes starting a timer in response to the UL transmission, determining that failure of the UL transmission has occurred if no Hybrid Automatic Repeat Request ("HARQ") Acknowledgement ("ACK") feedback is received within the duration of timer, and switching to a second beam for subsequent UL transmission of the first TB in response to determining that failure of the UL transmission has occurred.

Another method of a UE includes performing a first LBT procedure using omni-directional sensing to acquire a first Channel Occupancy Time ("COT") and performing a first UL transmission of a first TB during the first COT and using a first beam in response to successful LBT, wherein the first UL transmission uses a first portion of the first COT. The second method includes performing a directional LBT procedure for a second beam to acquire a remaining portion of the first COT.

Code for carrying out operations for embodiments may be any number of lines and may be written in any combination of one or more programming languages including an object-oriented programming language such as Python, Ruby, Java, Smalltalk, C++, or the like, and conventional procedural programming languages, such as the "C" programming language, or the like, and/or machine languages such as assembly languages. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network ("LAN"), wireless LAN ("WLAN"), or a wide area network ("WAN"), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider ("ISP")).

The code may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the code which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart diagrams and/or block diagrams.

Generally, the present disclosure describes systems, methods, and apparatus for beam switching after LBT procedure. The present disclosure deals with the channel access mechanism in unlicensed band for high frequency range (namely FR2 or FR4), but not limited to that. More specifically, as beam-based operation is assumed for unlicensed spectrum in FR2 and beyond, it is crucial to perform listen-before-talk ("LBT") in a specific beam direction(s) rather than omni-directional LBT.

The present disclosure describes panel switching during LBT failures at the UE side in connected mode and provide solutions to on how to allow faster channel access for AUL by switching beam/panel based LBT failures at the UE in connected state also considering interference/LBT failures at gNB side. Basically, if there is an LBT failure at UE in specific panel/beam direction, then how to facilitate the UE to autonomously switch to from one panel/beam to another for performing faster LBT. Alternatively, how to allow parallel LBT using multiple panels at the same time for AUL.

In NR-U, channel access in both downlink and uplink relies on the LBT; however, no beamforming is considered for LBT in NR-U in Rel. <NUM> and only omni-directional LBT is assumed. The NR-U LBT procedures for channel access can be summarized as follows:.

Both gNB-initiated and UE-initiated COTs use Category <NUM> ("Cat-<NUM>") LBT where the start of a new transmission burst always perform LBT with exponential back-off. Only with exception, when the DRS must be at most one ms in duration and is not multiplexed with unicast PDSCH. As used herein, a Cat-<NUM> LBT procedure refers to LBT with a random back-off and with a variable size contention window.

UL transmission within a gNB initiated COT or a subsequent DL transmission within a UE or gNB initiated COT can transmit immediately without sensing only if the gap from the end of the previous transmission is not more than <NUM>, otherwise Category <NUM> ("Cat-<NUM>") LBT must be used and the gap cannot exceed <NUM>. As used herein, a Cat-<NUM> LBT procedure refers to LBT without random back-off.

In various embodiments, a UE may include multiple antenna panels. An identifier (ID) that can be used at least for indicating panel-specific UL transmission is supported. The ID may be defined considering the possibility to reuse/modification of Rel-<NUM> specification support or introducing new ID. In certain embodiments, the UE is not required to explicitly disclose its UL antenna panel implementation. In other embodiments, UE capability signaling may be used for panel-specific UL transmission.

A panel identifier (panel ID) to be used at least for indicating panel-specific UL transmission may include one of the following: <NUM>) an SRS resource set ID; <NUM>) an ID, which is directly associated to a reference RS resource and/or resource set; <NUM>) an ID, which can be assigned for a target RS resource or resource set; and <NUM>) an ID which is additionally configured in spatial relation information. The panel ID (not excluding to reuse existing ID) may be used for panel-selection-based transmission of PUSCH, PUCCH and SRS, among multiple activated panels.

In some embodiments, multiple panels are implemented on a UE and only one panel can be activated at a time, with a predetermined panel switching/activation delay. In some embodiments, multiple panels are implemented on a UE and multiple panels can be activated at a time and one or more panels can be used for transmission. In some embodiments, multiple panels are implemented on a UE and multiple panels can be activated at a time but only one panel can be used for transmission. Note that this does not require a UE to always activate multi-panels simultaneously. Also note that the UE can control the panel activation/deactivation.

In other embodiments, a new panel-ID may be used, which can be implicitly/explicitly applied to the transmission for a target RS resource or resource set, for PUCCH resource, for SRS resource. In such embodiments, a panel specific signaling is performed using the new panel-ID implicitly (e.g., by DL beam reporting enhancement) or explicitly. If explicitly signaled, the ID can be configured in the target RS/channel or reference RS (e.g., in the DL RS resource configuration or in spatial relation info).

As used herein, a "UE panel" refers to a logical entity that may be mapped to physical UE antennas. For certain condition(s), the gNB can assume the mapping between the UE's physical antennas to the logical entity "UE panel" activated for transmission will not be changed. Depending on the UE's own implementation, a "UE panel" can have at least the following functionality as an operational role of Unit of antenna group to control its Tx beam independently.

A first problem addressed by the present disclosure relates to how to handle UL Tx failure during multi-panel operation with spatial LBT. The disclosure provides several solutions involving on panel switching during LBT failures at the UE side in connected mode and provide solutions to on how to allow faster channel access for autonomous uplink ("AUL") transmission by switching beam/panel based LBT failures at the UE in connected state also considering interference/LBT failures at gNB side.

The disclosure provides solutions for how to facilitate the UE to autonomously switch to from one panel/beam to another for performing faster LBT if there is an LBT failure at UE in specific panel/beam direction. The disclosure provides solutions for how to allow parallel LBT using multiple panels at the same time for AUL.

A second problem addressed by the present disclosure relates to UE-initiated beam/panel switching during the same Channel Occupancy Time ("COT"). The disclosure provides solutions for how to acquire a remaining portion of the COT during multi-panel operation with spatial LBT.

<FIG> depicts a wireless communication system <NUM> for beam switching after LBT procedure, according to embodiments of the disclosure. In one embodiment, the wireless communication system <NUM> includes at least one remote unit <NUM>, a radio access network ("RAN") <NUM>, and a mobile core network <NUM>. The RAN <NUM> and the mobile core network <NUM> form a mobile communication network. The RAN <NUM> may be composed of a base unit <NUM> with which the remote unit <NUM> communicates using wireless communication links <NUM>. Even though a specific number of remote units <NUM>, base units <NUM>, wireless communication links <NUM>, RANs <NUM>, and mobile core networks <NUM> are depicted in <FIG>, one of skill in the art will recognize that any number of remote units <NUM>, base units <NUM>, wireless communication links <NUM>, RANs <NUM>, and mobile core networks <NUM> may be included in the wireless communication system <NUM>.

In one implementation, the RAN <NUM> is compliant with the <NUM> system specified in the 3GPP specifications. For example, the RAN <NUM> may be a NG-RAN, implementing NR RAT and/or LTE RAT. In another example, the RAN <NUM> may include non-3GPP RAT (e.g., Wi-Fi® or Institute of Electrical and Electronics Engineers ("IEEE") <NUM>-family compliant WLAN). In another implementation, the RAN <NUM> is compliant with the LTE system specified in the 3GPP specifications. More generally, however, the wireless communication system <NUM> may implement some other open or proprietary communication network, for example Worldwide Interoperability for Microwave Access ("WiMAX") or IEEE <NUM>-family standards, among other networks.

In one embodiment, the remote units <NUM> may include computing devices, such as desktop computers, laptop computers, personal digital assistants ("PDAs"), tablet computers, smart phones, smart televisions (e.g., televisions connected to the Internet), smart appliances (e.g., appliances connected to the Internet), set-top boxes, game consoles, security systems (including security cameras), vehicle on-board computers, network devices (e.g., routers, switches, modems), or the like. Moreover, the remote units <NUM> may be referred to as the UEs, subscriber units, mobiles, mobile stations, users, terminals, mobile terminals, fixed terminals, subscriber stations, user terminals, wireless transmit/receive unit ("WTRU"), a device, or by other terminology used in the art. In various embodiments, the remote unit <NUM> includes a subscriber identity and/or identification module ("SIM") and the mobile equipment ("ME") providing mobile termination functions (e.g., radio transmission, handover, speech encoding and decoding, error detection and correction, signaling and access to the SIM). In certain embodiments, the remote unit <NUM> may include a terminal equipment ("TE") and/or be embedded in an appliance or device (e.g., a computing device, as described above).

The remote units <NUM> may communicate directly with one or more of the base units <NUM> in the RAN <NUM> via uplink ("UL") and downlink ("DL") communication signals. Furthermore, the UL and DL communication signals may be carried over the wireless communication links <NUM>. Here, the RAN <NUM> is an intermediate network that provides the remote units <NUM> with access to the mobile core network <NUM>. As described in greater detail below, the RAN <NUM> may send a measurement and reporting configuration <NUM> to the remote unit <NUM>, wherein the remote unit <NUM> sends a measurement report <NUM> to the RAN <NUM>.

In some embodiments, the remote units <NUM> communicate with an application server <NUM> via a network connection with the mobile core network <NUM>. For example, an application <NUM> (e.g., web browser, media client, telephone and/or Voice-over-Internet-Protocol ("VoIP") application) in a remote unit <NUM> may trigger the remote unit <NUM> to establish a protocol data unit ("PDU") session (or other data connection) with the mobile core network <NUM> via the RAN <NUM>. The mobile core network <NUM> then relays traffic between the remote unit <NUM> and the application server <NUM> in the packet data network <NUM> using the PDU session. The PDU session represents a logical connection between the remote unit <NUM> and the User Plane Function ("UPF") <NUM>.

In order to establish the PDU session (or PDN connection), the remote unit <NUM> must be registered with the mobile core network <NUM> (also referred to as "attached to the mobile core network" in the context of a Fourth Generation ("<NUM>")system). Note that the remote unit <NUM> may establish one or more PDU sessions (or other data connections) with the mobile core network <NUM>. As such, the remote unit <NUM> may have at least one PDU session for communicating with the packet data network <NUM>. The remote unit <NUM> may establish additional PDU sessions for communicating with other data networks and/or other communication peers.

In the context of a <NUM> system ("5GS"), the term "PDU Session" refers to a data connection that provides end-to-end ("E2E") user plane ("UP") connectivity between the remote unit <NUM> and a specific Data Network ("DN") through the UPF <NUM>. A PDU Session supports one or more Quality of Service ("QoS") Flows. In certain embodiments, there may be a one-to-one mapping between a QoS Flow and a QoS profile, such that all packets belonging to a specific QoS Flow have the same <NUM> QoS Identifier ("5QI").

In the context of a <NUM>/LTE system, such as the Evolved Packet System ("EPS"), a Packet Data Network ("PDN") connection (also referred to as EPS session) provides E2E UP connectivity between the remote unit and a PDN. The PDN connectivity procedure establishes an EPS Bearer, i.e., a tunnel between the remote unit <NUM> and a Packet Gateway ("PGW", not shown) in the mobile core network <NUM>. In certain embodiments, there is a one-to-one mapping between an EPS Bearer and a QoS profile, such that all packets belonging to a specific EPS Bearer have the same QoS Class Identifier ("QCI").

The base units <NUM> may be distributed over a geographic region. In certain embodiments, a base unit <NUM> may also be referred to as an access terminal, an access point, a base, a base station, a Node-B ("NB"), an Evolved Node B (abbreviated as eNodeB or "eNB," also known as Evolved Universal Terrestrial Radio Access Network ("E-UTRAN") Node B), a <NUM>/NR Node B ("gNB"), a Home Node-B, a relay node, a RAN node, or by any other terminology used in the art. The base units <NUM> are generally part of a RAN, such as the RAN <NUM>, that may include one or more controllers communicably coupled to one or more corresponding base units <NUM>. These and other elements of radio access network are not illustrated but are well known generally by those having ordinary skill in the art. The base units <NUM> connect to the mobile core network <NUM> via the RAN <NUM>.

The base units <NUM> may serve a number of remote units <NUM> within a serving area, for example, a cell or a cell sector, via a wireless communication link <NUM>. The base units <NUM> may communicate directly with one or more of the remote units <NUM> via communication signals. Generally, the base units <NUM> transmit DL communication signals to serve the remote units <NUM> in the time, frequency, and/or spatial domain. Furthermore, the DL communication signals may be carried over the wireless communication links <NUM>. The wireless communication links <NUM> may be any suitable carrier in licensed or unlicensed radio spectrum. The wireless communication links <NUM> facilitate communication between one or more of the remote units <NUM> and/or one or more of the base units <NUM>. Note that during NR-U operation, the base unit <NUM> and the remote unit <NUM> communicate over unlicensed radio spectrum.

In one embodiment, the mobile core network <NUM> is a 5GC or an Evolved Packet Core ("EPC"), which may be coupled to a packet data network <NUM>, like the Internet and private data networks, among other data networks. A remote unit <NUM> may have a subscription or other account with the mobile core network <NUM>. Each mobile core network <NUM> belongs to a single PLMN.

The mobile core network <NUM> includes several network functions ("NFs"). As depicted, the mobile core network <NUM> includes at least one UPF <NUM>. The mobile core network <NUM> also includes multiple control plane ("CP") functions including, but not limited to, an Access and Mobility Management Function ("AMF") <NUM> that serves the RAN <NUM>, a Session Management Function ("SMF") <NUM>, a Policy Control Function ("PCF") <NUM>, and a Unified Data Management function ("UDM"). In some embodiments, the UDM is co-located with a User Data Repository ("UDR"), depicted as combined entity "UDM/UDR" <NUM>. In various embodiments, the mobile core network <NUM> may also include an Authentication Server Function ("AUSF"), a Network Repository Function ("NRF") (used by the various NFs to discover and communicate with each other over Application Programming Interfaces ("APIs")), or other NFs defined for the 5GC. In certain embodiments, the mobile core network <NUM> may include an authentication, authorization, and accounting ("AAA") server.

In various embodiments, the mobile core network <NUM> supports different types of mobile data connections and different types of network slices, wherein each mobile data connection utilizes a specific network slice. Here, a "network slice" refers to a portion of the mobile core network <NUM> optimized for a certain traffic type or communication service. A network instance may be identified by a single-network slice selection assistance information ("S-NSSAI") while a set of network slices for which the remote unit <NUM> is authorized to use is identified by network slice selection assistance information ("NSSAI"). Here, "NSSAI" refers to a vector value including one or more S-NSSAI values. In certain embodiments, the various network slices may include separate instances of network functions, such as the SMF <NUM> and UPF <NUM>. In some embodiments, the different network slices may share some common network functions, such as the AMF <NUM>. The different network slices are not shown in <FIG> for ease of illustration, but their support is assumed.

Although specific numbers and types of network functions are depicted in <FIG>, one of skill in the art will recognize that any number and type of network functions may be included in the mobile core network <NUM>. Moreover, in an LTE variant where the mobile core network <NUM> is an EPC, the depicted network functions may be replaced with appropriate EPC entities, such as a Mobility Management Entity ("MME"), a Serving Gateway ("SGW"), a PGW, a Home Subscriber Server ("HSS"), and the like. For example, the AMF <NUM> may be mapped to an MME, the SMF <NUM> may be mapped to a control plane portion of a PGW and/or to an MME, the UPF <NUM> may be mapped to an SGW and a user plane portion of the PGW, the UDM/UDR <NUM> may be mapped to an HSS, etc..

While <FIG> depicts components of a <NUM> RAN and a <NUM> core network, the described embodiments for beam switching after LBT procedure apply to other types of communication networks and RATs, including IEEE <NUM> variants, Global System for Mobile Communications ("GSM", i.e., a <NUM> digital cellular network), General Packet Radio Service ("GPRS"), Universal Mobile Telecommunications System ("UMTS"), LTE variants, CDMA <NUM>, Bluetooth, ZigBee, Sigfox, and the like.

The remote unit <NUM> is configured with multiple UE panels either during initial access or in the connected mode using SRI. As used herein, a "UE panel" refers to a logical entity that may be mapped to physical UE antennas. For certain condition(s), the gNB can assume the mapping between UE's physical antennas to the logical entity "UE panel" activated for transmission will not be changed. Depending on the remote unit <NUM> implementation, a "UE panel" can have at least the functionality as an operational role of Unit of antenna group to control its Tx beam independently.

According to a first solution, the remote unit <NUM> handles UL Tx failure by switching to a different panel/beam and using the same configured grant resources.

According to a second solution, the remote unit <NUM> handles UL Tx failure by switching to a different panel/beam, where the different panels/beams have different configured grant resources.

According to a third solution, the remote unit <NUM> handles UL Tx failure by performing LBT on multiple panels/beams and selecting only one panel/beam for UL transmission. Here, the multiple panels/beams use the same configured grant resources.

According to a third solution, the remote unit <NUM> handles UL Tx failure by performing LBT on multiple panels/beams and selecting only one panel/beam for UL transmission. Here, the multiple panels/beams use different configured grant resources. Moreover, the remote unit <NUM> selects multiple panels/beams for UL transmission.

In the following descriptions, the term "RAN node" is used for the base station but it is replaceable by any other radio access node, e.g., gNB, eNB, Base Station ("BS"), Access Point ("AP"), etc. Further, the operations are described mainly in the context of <NUM> NR. However, the proposed solutions/methods are also equally applicable to other mobile communication systems supporting measurement reporting in non-public networks.

<FIG> depicts a NR protocol stack <NUM>, according to embodiments of the disclosure. While <FIG> shows a UE <NUM>, a RAN node <NUM> and an AMF <NUM> in a <NUM> core network ("5GC"), these are representative of a set of remote units <NUM> interacting with a base unit <NUM> and a mobile core network <NUM>. As depicted, the protocol stack <NUM> comprises a User Plane protocol stack <NUM> and a Control Plane protocol stack <NUM>. The User Plane protocol stack <NUM> includes a physical ("PHY") layer <NUM>, a Medium Access Control ("MAC") sublayer <NUM>, the Radio Link Control ("RLC") sublayer <NUM>, a Packet Data Convergence Protocol ("PDCP") sublayer <NUM>, and Service Data Adaptation Protocol ("SDAP") layer <NUM>. The Control Plane protocol stack <NUM> includes a physical layer <NUM>, a MAC sublayer <NUM>, a RLC sublayer <NUM>, and a PDCP sublayer <NUM>. The Control Plane protocol stack <NUM> also includes a Radio Resource Control ("RRC") layer <NUM> and a Non-Access Stratum ("NAS") layer <NUM>.

The AS layer (also referred to as "AS protocol stack") for the User Plane protocol stack <NUM> consists of at least SDAP, PDCP, RLC and MAC sublayers, and the physical layer. The AS layer for the Control Plane protocol stack <NUM> consists of at least RRC, PDCP, RLC and MAC sublayers, and the physical layer. The Layer-<NUM> ("L2") is split into the SDAP, PDCP, RLC and MAC sublayers. The Layer-<NUM> ("L3") includes the RRC sublayer <NUM> and the NAS layer <NUM> for the control plane and includes, e.g., an Internet Protocol ("IP") layer or PDU Layer (not depicted) for the user plane. L1 and L2 are referred to as "lower layers," while L3 and above (e.g., transport layer, application layer) are referred to as "higher layers" or "upper layers.

The physical layer <NUM> offers transport channels to the MAC sublayer <NUM>. The physical layer <NUM> may perform CCA/LBT procedure as described herein. In certain embodiments, the physical layer <NUM> may send a notification of UL LBT failure to a MAC entity at the MAC sublayer <NUM>. The MAC sublayer <NUM> offers logical channels to the RLC sublayer <NUM>. The RLC sublayer <NUM> offers RLC channels to the PDCP sublayer <NUM>. The PDCP sublayer <NUM> offers radio bearers to the SDAP sublayer <NUM> and/or RRC layer <NUM>. The SDAP sublayer <NUM> offers QoS flows to the core network (e.g., 5GC). The RRC layer <NUM> provides for the addition, modification, and release of Carrier Aggregation and/or Dual Connectivity. The RRC layer <NUM> also manages the establishment, configuration, maintenance, and release of Signaling Radio Bearers ("SRBs") and Data Radio Bearers ("DRBs").

The NAS layer <NUM> is between the UE <NUM> and the 5GC <NUM>. NAS messages are passed transparently through the RAN. The NAS layer <NUM> is used to manage the establishment of communication sessions and for maintaining continuous communications with the UE <NUM> as it moves between different cells of the RAN. In contrast, the AS layer is between the UE <NUM> and the RAN carries information over the wireless portion of the network.

<FIG> depicts a scenario <NUM> for directional LBT, according to embodiments of the disclosure. The scenario <NUM> may involve a UE <NUM>, a RAN node <NUM> with which the UE <NUM> desires to send a UL transmission, and an access point ("AP") <NUM> which is representative of a potential user of the same communication frequencies as the UE <NUM> and RAN node <NUM>. The UE <NUM> may be one implementation of the remote unit <NUM> and the RAN node <NUM> may be one implementation of the base unit <NUM>. The UE <NUM> has generated a UL TB for transmission to the RAN node <NUM> and thus performs performing a LBT procedure for a configured set of Tx panels/beams corresponding to the UL transmission.

As depicted, the UE <NUM> performs an LBT procedure on at least beam #<NUM> at time 't1,' i.e., in preparation for UL transmission using CG resources. Note that the LBT procedure determines whether the RAN node <NUM>, the AP <NUM>, or another device is using the channel (i.e., radio frequencies) that the UE <NUM> is to use for the UL transmission. Here, it is assumed that beam #<NUM> is a sensing beam that corresponds to a first UE panel and that the UE <NUM> supports multiple panels. As depicted, LBT is successful for sensing Beam #<NUM>. Where the LBT procedure includes assessing multiple beams, here is it assumed that a Tx beam and/or UE panel corresponding to the sensing Beam #<NUM> is selected.

The UE <NUM> performs UL transmission on CG resources using Tx Beam #<NUM> and begins a UL failure timer. However, there is uplink transmission failure and thus the RAN node <NUM> either does not receive the UL transmission or is unable to decode the UL transmission. Because the UE does not receive a HARQ-ACK from the RAN node <NUM> before expiry of the failure timer, the UE determines that the UL transmission failed. As used herein, "HARQ-ACK" may represent collectively the Positive Acknowledge ("ACK") and the Negative Acknowledge ("NACK"). ACK means that a TB is correctly received while NACK (or NAK) means a TB is erroneously received.

In response to determining UL Tx failure for Tx Beam #<NUM>, the UE <NUM> switches to a second sensing beam/UE panel and performs LBT on at least beam #<NUM> at time 't2,' i.e., in preparation for UL transmission using a second occasion of CG resources. Here, it is assumed that LBT is successful for the sensing panel/beam #<NUM>. Thus, the UE <NUM> performs UL transmission on the corresponding Tx panel/beam #<NUM>. However, if LBT fails for Rx panel/beam #<NUM>, then the UE <NUM> continues performing a LBT procedure for the configured set of Tx panels/beams until LBT success or until LBT fails for all configured panels/beams.

<FIG> depicts an LBT procedure <NUM> for a radio frame <NUM> for unlicensed communication, according to embodiments of the disclosure. When a communication channel is a wide bandwidth unlicensed carrier <NUM> (e.g., several hundred MHz, the CCA/LBT procedure relies on detecting the energy level on multiple sub-bands <NUM> of the communications channel as shown in <FIG>. The LBT parameters (such as type/duration, clear channel assessment parameters, etc.) are configured in the UE <NUM> by the RAN node <NUM>. In one embodiment, the LBT procedure is performed at the PHY layer <NUM>.

<FIG> also depicts frame structure of the radio frame <NUM> for unlicensed communication between the UE <NUM> and RAN node <NUM>. The radio frame <NUM> may be divided into subframes (indicated by subframe boundaries <NUM>) and may be further divided into slots (indicated by slot boundaries <NUM>). The radio frame <NUM> uses a flexible arrangements where uplink and downlink operations are on the same frequency channel but are separated in time. However, the subframes are not configured as a downlink subframe or an uplink subframe and a particular subframe may be used by either the UE <NUM> or RAN node <NUM>. As discussed previously, LBT is performed prior to a transmission. Where LBT does not coincide with a slot boundary <NUM>, a reservation signal <NUM> may be transmitted to reserve the channel until the slot boundary is reached and data transmission begins.

As discussed above, according to a first solution the UE <NUM> is configured with the same CG resource for different panels/beams. When the UE <NUM> performs CCA/LBT in one of the configured sensing beams and transmits a TB in one of the configured Tx beams after the success of LBT, the UE <NUM> initiates (i.e., starts) a timer. The UE <NUM> detects (i.e., declares) UL Tx failure if it does not receive HARQ feedback within a specified time, e.g., at the expiry of the timer. In one embodiment, this timer is the CG retransmission timer. In another embodiment, this timer is a new timer introduced for the purpose of detecting UL Tx failure.

Note that the CG retransmission timer is implicitly associated with the decoding failure at the RAN node due to interference or channel condition or short LBT failure at the transmission of the RAN node. However, in another implementation of the first solution, a new timer - different than the CG retransmission timer - is introduced which may be an LBT/CCA specific timer that can be associated with a certain channel access priority class. Regardless of implementation, the timer is started after the transmission of the TB in the uplink and stops after receiving corresponding HARQ feedback. Additionally, expiry of the timer triggers autonomous panel/beam switching, as discussed below.

As used herein, UE autonomous behavior refers to a UE-initiated behavior, where the UE performs the behavior in response to an internal trigger and without waiting for (and receiving) instructions from the network (e.g., RAN and/or CN). Thus, the UE <NUM> autonomously switching to a different panel/beam refers to a UE-initiated switch to a different panel/beam, wherein the UE <NUM> performs with switch without receiving instructions from the network to switch the panel/beam.

Upon detecting (i.e., determining) UL Tx failure, the UE <NUM> is allowed to autonomously switch to a different panel/beam to perform CCA/LBT for the (re)-transmission of the same TB in the same CG resource. In one embodiment, the UE <NUM> autonomously switches to a different sensing beam - from among the configured sensing beams - for performing CCA/LBT. In another embodiment, the UE <NUM> autonomously switches to a different Tx beam - from among the configured Tx beams - for retransmitting the TB.

In embodiments of the first solution, the RAN node <NUM> (e.g., gNB) reports the HARQ feedback with the same spatial filter used for the CG transmission. Aperiodic Uplink Control Information ("A-UCI") indicates the panel/beam ID used by the UE <NUM> in the CG resource. Here, the UE <NUM> may choose the first panel for LBT-UL transmission from a set of configured panels/beams based on the DL channel signal strength, where the selection may be based on the measurement on SSB, CSI-RS, etc..

According to the second solution, the UE <NUM> is configured with different CG resource for different panels/beams. As in the first solution, the UE <NUM> performs CCA/LBT for each TX panel/beam and transmits a TB after the success of LBT. If the UE <NUM> does not receive HARQ feedback within a specified time period (i.e., at the expiry of the CG retransmission timer or the new LBT/CCA specific timer, discussed above), then the UE <NUM> declares UL Tx failure.

Again, the RAN node <NUM> reports the HARQ feedback with the same spatial filter used for the CG transmission, A-UCI indicates the panel/beam ID used by the UE in the CG resource. Upon detecting/declaring UL Tx failure, the UE <NUM> may autonomously switch to a different panel/beam to perform CCA/LBT for the transmission of same TB in the different CG resources. However, in the second solution each CG resource is associated with a TX panel/beam of the UE <NUM>.

In one embodiment of the second solution, the UE <NUM> starts the CG retransmission timer after transmission of the TB and declares UL Tx failure upon expiry of the CG retransmission timer. As described above, the CG retransmission timer may be used is implicitly associated with the decoding failure at the RAN node due to interference or channel condition or short LBT failure at the transmission of the RAN node.

In another embodiment of the second solution, the UE <NUM> starts a new timer - different than the CG retransmission timer - after transmission of the TB and declares UL Tx failure upon expiry of the CG retransmission timer. As described above, the new timer may be an LBT/CCA specific timer that can be associated with a certain channel access priority class. Alternatively, the new timer may be a CG-specific timer. Regardless of implementation, the timer is started after the transmission of the TB in the uplink and stops after receiving corresponding HARQ feedback. Expiry of the timer triggers autonomous panel/beam switching.

According to the second solution, the UE <NUM> may choose the first panel for LBT-UL transmission from the set of panels/beams based on the DL channel signal strength. Here, the selection may be based on the measurement on SSB, CSI-RS, etc. The UE <NUM> then chooses the CG resource which has same TBS for the retransmission. Alternatively, the UE <NUM> may first choose the CG resource which has same TBS and then choose the UE panel for UL transmission. The UE <NUM> may choose to use the same HARQ process for transmitting in different CG resource as long as the TBS is same.

According to the third solution, the UE <NUM> may be configured with the same CG resources for multiple panels/beams. Moreover, the UE <NUM> performs LBT on a plurality of panels/beams, where only one panel/beam is selected for UL transmission.

The UE <NUM> performs first LBT/CCA with one panel/beam and transmit a TB after the successful LBT/CCA procedure. Then, after the expiry of the CG retransmission timer (or the new LBT/CCA specific timer introduced above) without receiving HARQ-ACK, the UE <NUM> performs second LBT with another set of panels/beams on the same CG resource. In some embodiments, the second LBT may be performed using plurality of panels/beams simultaneously on the same CG resource. After the successful completion of LBT/CCA procedure, the UE <NUM> performs UL transmission on panel/beam based on LBT-ED, i.e., where ED is compared for different panels/beams and a panel/beam is selected based on the least ED value.

In another implementation, the first LBT may be performed on one panel/beam and when it fails, then the second LBT may be performed on two panels/beams simultaneously from the configured set of panels/beams and when it fails, then the third LBT may be performed on three panels/beams simultaneously from the configured set of panels/beams, and so on.

According to the fourth solution, the UE <NUM> may be configured with different CG resources for the different panels/beams. The UE <NUM> performs LBT on a plurality of panels/beams. Moreover, the UE may select a plurality of panels/beams for UL transmission on different CG resources.

The UE <NUM> may perform LBT/CCA simultaneously on configured set of panels/beams simultaneously and same TB is repeated across different CG resources after the success of the LBT. Here, CG resources are assigned to each TX panel/beam separately. The RAN node provides HARQ feedback in the same spatial filter that is used for receiving the CG resources. The UE <NUM> stops the retransmission of the initial transmission in all CG resources after it receives at least one HARQ-ACK feedback and also flushes the HARQ buffer of all HARQ process. In one implementation, HARQ feedback may be transmitted from one or plurality of panels from the RAN node after short LBT.

The above strategies for handling directional LBT and UL failure can be extended to other channels used in the wireless communication system.

According to a fifth solution, the UE <NUM> may perform RACH preamble transmission using another panel/beam when LBT fails for a first panel/beam. When the UE <NUM> fails to transmit a RACH preamble from the panel associated with the highest DL signal reception quality of SSB due to LBT failure, then the UE <NUM> may autonomously switch to another panel/beam for the RACH preamble transmission. Here, the UE <NUM> may choose the panel/beam chosen based on the next best DL signal reception quality of SSB. In certain embodiments, the UE <NUM> does not increment the preamble transmission counter and preamble ramping counters when autonomously switching to another panel/beam for the RACH preamble transmission.

In an alternate implementation, CCA/LBT may be performed simultaneously using plurality of panels/beams and RACH preamble transmission is performed only using one panel/beam where the panel/beam is chosen for RACH preamble transmission based on the DL signal strength reception quality. In another implementation, the RACH preamble transmission + MsgA is performed on plurality of panels after the CCA/LBT success using where MsgA (i.e., the first message of a <NUM>-step random access procedure) contains the UE identity and panel ID/beam ID and the RAN node <NUM> may transmit only one RAR based on the reception quality of the RACH preamble.

According to a sixth solution, the UE <NUM> performs CCA for omni-directional transmissions and performs short LBT for directional transmissions. Here, the UE <NUM> may perform "first LBT" for, e.g., CAT-<NUM> LBT like counter-based access with exponential back off in an omni-directional manner and it successfully or fails (both cases) to acquire the channel or want to switch to other panel/beam for directional transmission. Then, UE <NUM> may perform "second LBT" using a CAT-<NUM> LBT type using shorter LBT like energy sensing either for <NUM> or <NUM>. The sixth solution is applicable to data channel, control channel, RACH/SRS transmission. In another implementation of the sixth solution, the second LBT may also be performed simultaneously using a plurality of panels/beams.

According to a seventh solution, the group-common Downlink Control Information ("DCI") from the RAN node <NUM> (e.g., gNB) indicates plurality of panels/beams where the CCA/LBT is successful as part of DL COT sharing information. Here, the RAN node <NUM> may indicate in DCI a plurality of panels/beams information in the "from panel/beam ID" element or "CSI-RS configuration" element or "SSB configuration" element or in the form of Transmission Configuration Indicator ("TCI") states or QCL-Type D, where the CCA/LBT are successfully performed for the DL initiated COT sharing. In such case, a COT sharing field in the DCI contains plurality of COT sharing indicator each represented by a TCI state or a QCL-Type D relationship with one or more transmission beam(s) configured semi-statically. The UE <NUM>, after receiving this DCI information containing DL COT sharing indicator, may then choose to perform CCA/LBT in any of the indicated beam/panel or all simultaneously using shorter LBT (e.g., CAT-<NUM> LBT type) for UL transmission. The UL transmission could be performed using one or plurality of beam/panels which could be further scheduled by the DCI or by autonomous uplink in the configured CG resource as explained in the previous embodiments.

Regarding Quasi-Co-Location ("QCL") assumptions, in certain embodiments the UE <NUM> is configured with a list of up to M TCI-State configurations within the higher layer parameter PDSCH-Config to decode PDSCH according to a detected PDCCH with DCI intended for the UE and the given serving cell, where the value of M depends on the UE capability maxNumberConfiguredTCIstatesPerCC.

Each TCI-State configuration contains parameters for configuring a QCL relationship between one or two downlink reference signals and the DM-RS ports of the PDSCH, the DM-RS port of PDCCH or the CSI-RS port(s) of a CSI-RS resource. The QCL relationship is configured by the higher layer parameter 'qcl-Type1' for the first DL RS, and the higher layer parameter 'qcl-Type2' for the second DL RS (if configured). For the case of two DL RSs, the QCL types are not the same, regardless of whether the references are to the same DL RS or different DL RSs. The quasi co-location types corresponding to each DL RS are given by the higher layer parameter qcl-Type in QCL-Info and may take one of the following values:.

In some embodiments, the UE <NUM> receives an activation command used to map up to eight TCI states to the codepoints of the DCI field 'Transmission Configuration Indication' in one CC/DL BWP or in a set of CCs/DL BWPs, respectively. When a set of TCI state IDs are activated for a set of CCs/DL BWPs, where the applicable list of Component Carriers ("CCs") is determined by indicated CC in the activation command, the same set of TCI state IDs are applied for all DL BWPs in the indicated CCs.

When a UE <NUM> supports two TCI states in a codepoint of the DCI field 'Transmission Configuration Indication' the UE <NUM> may receive an activation command, then the activation command is used to map up to eight combinations of one or two TCI states to the codepoints of the DCI field 'Transmission Configuration Indication'.

When the UE <NUM> is to transmit a PUCCH with HARQ-ACK information in slot n corresponding to the PDSCH carrying the activation command, the indicated mapping between TCI states and codepoints of the DCI field 'Transmission Configuration Indication' should be applied starting from the first slot that is after slot <MAT> where µ is the SCS configuration for the PUCCH. If parameter tci-PresentInDCI is set to "enabled" or tci-PresentInDCI-ForFormat1_2 is configured for the Control Resource Set ("CORESET") scheduling the PDSCH, and the time offset between the reception of the DL DCI and the corresponding PDSCH is equal to or greater than timeDurationForQCL if applicable, after a UE <NUM> receives an initial higher layer configuration of TCI states and before reception of the activation command, the UE <NUM> may assume that the DM-RS ports of PDSCH of a serving cell are quasi co-located with the SS/PBCH block determined in the initial access procedure with respect to 'QCL-TypeA', and when applicable, also with respect to 'QCL-TypeD'.

If a UE <NUM> is configured with the higher layer parameter tci-PresentInDCI that is set as 'enabled' for the CORESET scheduling the PDSCH, the UE <NUM> assumes that the TCI field is present in the DCI format 1_1 of the PDCCH transmitted on the CORESET. If a UE is configured with the higher layer parameter tci-PresentInDCI-ForFormat1_2 for the CORESET scheduling the PDSCH, the UE assumes that the TCI field with a DCI field size indicated by tci-PresentInDCI-ForFormat1_2 is present in the DCI format 1_2 of the PDCCH transmitted on the CORESET. If the PDSCH is scheduled by a DCI format not having the TCI field present, and the time offset between the reception of the DL DCI and the corresponding PDSCH is equal to or greater than a threshold timeDurationForQCL if applicable, where the threshold is based on reported UE capability for determining PDSCH antenna port quasi co-location, the UE <NUM> assumes that the TCI state or the QCL assumption for the PDSCH is identical to the TCI state or QCL assumption whichever is applied for the CORESET used for the PDCCH transmission.

If the PDSCH is scheduled by a DCI format having the TCI field present, the TCI field in DCI in the scheduling component carrier points to the activated TCI states in the scheduled component carrier or DL BWP, the UE <NUM> is to use the TCI-State according to the value of the 'Transmission Configuration Indication' field in the detected PDCCH with DCI for determining PDSCH antenna port quasi co-location. The UE <NUM> may assume that the DM-RS ports of PDSCH of a serving cell are quasi co-located with the RS(s) in the TCI state with respect to the QCL type parameter(s) given by the indicated TCI state if the time offset between the reception of the DL DCI and the corresponding PDSCH is equal to or greater than a threshold timeDurationForQCL, where the threshold is based on reported UE capability.

When the UE <NUM> is configured with a single slot PDSCH, the indicated TCI state should be based on the activated TCI states in the slot with the scheduled PDSCH. When the UE <NUM> is configured with a multi-slot PDSCH, the indicated TCI state should be based on the activated TCI states in the first slot with the scheduled PDSCH, and UE <NUM> is to expect the activated TCI states are the same across the slots with the scheduled PDSCH.

Independent of the configuration of tci-PresentInDCI and tci-PresentInDCI-ForFormat1_2 in RRC connected mode, if all the TCI codepoints are mapped to a single TCI state and the offset between the reception of the DL DCI and the corresponding PDSCH is less than the threshold timeDurationForQCL, the UE <NUM> may assume that the DM-RS ports of PDSCH of a serving cell are quasi co-located with the RS(s) with respect to the QCL parameter(s) used for PDCCH quasi co-location indication of the CORESET associated with a monitored search space with the lowest controlResourceSetId in the latest slot in which one or more CORESETs within the active BWP of the serving cell are monitored by the UE <NUM>. In this case, if the 'QCL-TypeD' of the PDSCH DM-RS is different from that of the PDCCH DM-RS with which they overlap in at least one symbol, the UE <NUM> is expected to prioritize the reception of PDCCH associated with that CORESET. This also applies to the intra-band CA case (when PDSCH and the CORESET are in different component carriers).

If none of configured TCI states for the serving cell of scheduled PDSCH contains 'QCL-TypeD', the UE <NUM> is to obtain the other QCL assumptions from the indicated TCI states for its scheduled PDSCH irrespective of the time offset between the reception of the DL DCI and the corresponding PDSCH. If a UE <NUM> configured by higher layer parameter PDCCH-Config that contains two different values of CORESETPoolIndex in ControlResourceSet, for both cases, when tci-PresentInDCI is set to 'enabled' and tci-PresentInDCI is not configured in RRC connected mode, if the offset between the reception of the DL DCI and the corresponding PDSCH is less than the threshold timeDurationForQCL, the UE <NUM> may assume that the DM-RS ports of PDSCH associated with a value of CORESETPoolIndex of a serving cell are quasi co-located with the RS(s) with respect to the QCL parameter(s) used for PDCCH quasi co-location indication of the CORESET associated with a monitored search space with the lowest CORESET-ID among CORESETs, which are configured with the same value of CORESETPoolIndex as the PDCCH scheduling that PDSCH, in the latest slot in which one or more CORESETs associated with the same value of CORESETPoolIndex as the PDCCH scheduling that PDSCH within the active BWP of the serving cell are monitored by the UE <NUM>.

If the offset between the reception of the DL DCI and the corresponding PDSCH is less than the threshold timeDurationForQCL and at least one configured TCI states for the serving cell of scheduled PDSCH contains the 'QCL-TypeD', and at least one TCI codepoint indicates two TCI states, the UE <NUM> may assume that the DM-RS ports of PDSCH of a serving cell are quasi co-located with the RS(s) with respect to the QCL parameter(s) associated with the TCI states corresponding to the lowest codepoint among the TCI codepoints containing two different TCI states.

For a periodic CSI-RS resource in an non-zero-power CSI-RS resource set ("NZP-CSI-RS-ResourceSet") configured with higher layer parameter trs-Info, the UE <NUM> is to expect that a TCI-State indicates one of the following quasi co-location type(s):.

For an aperiodic CSI-RS resource in an NZP-CSI-RS-ResourceSet configured with higher layer parameter trs-Info, the UE <NUM> is to expect that a TCI-State indicates 'QCL-TypeA' with a periodic CSI-RS resource in an NZP-CSI-RS-ResourceSet configured with higher layer parameter trs-Info and, when applicable, 'QCL-TypeD' with the same periodic CSI-RS resource.

For a CSI-RS resource in an NZP-CSI-RS-ResourceSet configured without higher layer parameter trs-Info and without the higher layer parameter repetition, the UE <NUM> is to expect that a TCI-State indicates one of the following quasi co-location type(s):.

For a CSI-RS resource in an NZP-CSI-RS-ResourceSet configured with higher layer parameter repetition, the UE <NUM> is to expect that a TCI-State indicates one of the following quasi co-location type(s):.

For the DM-RS of PDCCH, the UE <NUM> is to expect that a TCI-State indicates one of the following quasi co-location type(s):.

For the DM-RS of PDSCH, the UE <NUM> is to expect that a TCI-State indicates one of the following quasi co-location type(s):.

<FIG> depicts a user equipment apparatus <NUM> that may be used for beam switching after LBT procedure, according to embodiments of the disclosure. In various embodiments, the user equipment apparatus <NUM> is used to implement one or more of the solutions described above. The user equipment apparatus <NUM> may be one embodiment of the remote unit <NUM> and/or the UE <NUM>, described above. Furthermore, the user equipment apparatus <NUM> may include a processor <NUM>, a memory <NUM>, an input device <NUM>, an output device <NUM>, and a transceiver <NUM>.

In some embodiments, the input device <NUM> and the output device <NUM> are combined into a single device, such as a touchscreen. In certain embodiments, the user equipment apparatus <NUM> may not include any input device <NUM> and/or output device <NUM>. In various embodiments, the user equipment apparatus <NUM> may include one or more of: the processor <NUM>, the memory <NUM>, and the transceiver <NUM>, and may not include the input device <NUM> and/or the output device <NUM>.

As depicted, the transceiver <NUM> includes at least one transmitter <NUM> and at least one receiver <NUM>. In some embodiments, the transceiver <NUM> communicates with one or more cells (or wireless coverage areas) supported by one or more base units <NUM>. In various embodiments, the transceiver <NUM> is operable on unlicensed spectrum. Moreover, the transceiver <NUM> may include multiple UE panel supporting one or more beams. Additionally, the transceiver <NUM> may support at least one network interface <NUM> and/or application interface <NUM>. The application interface(s) <NUM> may support one or more APIs. The network interface(s) <NUM> may support 3GPP reference points, such as Uu, N1, PC5, etc. Other network interfaces <NUM> may be supported, as understood by one of ordinary skill in the art.

In certain embodiments, the processor <NUM> may include an application processor (also known as "main processor") which manages application-domain and operating system ("OS") functions and a baseband processor (also known as "baseband radio processor") which manages radio functions.

In various embodiments, the processor <NUM> controls the user equipment apparatus <NUM> to implement the above described UE behaviors. For example, the processor <NUM> may perform a LBT procedure at a first UE panel prior to a first occasion of CG resources. The processor <NUM> performs UL transmission of a first TB during the first occasion and using the first UE panel in response to successful LBT. In some embodiments, the UL transmission during the first occasion is accompanied by uplink control information ("UCI") identifying the UE panel used for transmission on the CG resource. Note that while the user equipment apparatus is described in terms of performing a LBT procedure for a "set of UE panels," in other embodiments LBT may be performed for a "set of beams. " As used herein, the term "panel/beam" (or similar notation) indicates that the description applies to a UE panel and/or beam.

In some embodiments, performing the LBT procedure comprises performing a clear channel assessment for a plurality of sensing UE panels. In such embodiments, performing the UL transmission of the first TB further comprises transmitting the first TB using at least one additional TX UE panel from the plurality of sensing UE panels for which LBT is successful, where each TX UE panel is associated with different CG resources.

In some embodiments, performing the UL transmission of the first TB during the first occasion includes selecting a single one of the plurality of TX UE panels and transmitting the first TB using the selected TX UE panel. In certain embodiments, the single one of the plurality of TX UE panels is selected based on a lowest energy detection value from the clear channel assessments of the sensing UE panel. In such embodiments, a QCL type-D relationship exists between the plurality of sensing UE panels and the plurality of TX UE panels.

The processor <NUM> and starts a timer in response to the UL transmission. In some embodiments, the timer comprises either a CG retransmission timer or a panel failure timer that is different from the CG retransmission timer. In certain embodiments, the panel failure timer is associated with a certain channel access priority class. In some embodiments, the value of the timer corresponds to a channel access priority class for the UL transmission.

In some embodiments, processor <NUM> determines failure of the UL transmission due to note receiving HARQ-ACK feedback within the duration of timer. In other embodiments, the processor <NUM> receives at least one HARQ-ACK feedback for the first TB and terminates the timer in response to the HARQ-ACK feedback. Here, the processor <NUM> further flushes a HARQ buffer associated with transmission of the first TB in response to receiving the HARQ-ACK feedback for the first TB. In certain embodiments, the processor further terminates retransmission of the first TB in response to receiving at least one HARQ-ACK feedback and flushes all HARQ buffers associated with transmission of the first TB.

The processor <NUM> switches to a second UE panel for subsequent UL transmission of the first TB in response to determining that failure of the UL transmission has occurred. In some embodiments, the UL transmission during the first occasion is associated with a first HARQ process. In such embodiments, performing UL transmission during the second occasion and using the second UE panel includes reusing the first HARQ process.

In some embodiments, the UE is configured with a multiple sensing UE panels. In such embodiments, the LBT procedure is performed using a first sensing UE panel, where switching to the second UE panel includes switching from the first sensing UE panel to a second sensing UE panel. In some embodiments, the UE is configured with a multiple TX UE panels. In such embodiments, the UL transmission of a first TB is performed for a first TX UE panel, where switching to the second UE panel includes switching from the first TX UE panel to a second TX UE panel.

In some embodiments, the second UE panel is associated with the same CG resources as the first UE panel. In such embodiments, the subsequent UL transmission is performed using the same time-frequency resource as the first occasion of CG resources. In other embodiments, each TX UE panel is associated with different CG resources. In such embodiments, the subsequent UL transmission is performed using a different time-frequency resource than the first occasion of CG resources. In certain embodiments, performing the subsequent UL transmission comprises selecting a CG resource having a same TB size as the first occasion of CG resources.

In various embodiments, the user equipment apparatus <NUM> supports time domain multiplexing ("TDM") of DL/UL transmissions in different panels/beams in the same COT. Here, the processor <NUM> may perform LBT (i.e., directional or omni-directional LBT) at the beginning of COT. In certain embodiments, the processor <NUM> performs additional directional LBT with sensing panel/beam that covers the next TX panel/beam for each panel/beam switching in the middle of COT, as described herein. Note that when additional direction LBT is performed, the first LBT may cover all TDM panels/beams or may cover only the first TX panel/beam. In other embodiments, the processor <NUM> does not perform additional LBT before each panel/beam switching in the middle of COT where the sensing panel(s)/beam(s) for the (first) LBT procedure cover all TDM panels/beams.

In various embodiments, the processor <NUM> performs a first LBT procedure using omni-directional sensing to acquire a first COT. Via the transceiver <NUM>, the processor <NUM> performs a first UL transmission of a first TB during the first COT and using a first TX panel/beam in response to successful LBT. Here, the first UL transmission uses a first portion of the first COT (i.e., does not use the entirety of the first COT). The processor <NUM> performs a directional LBT procedure for a second UE panel to acquire a remaining portion of the first COT.

In some embodiments, the processor <NUM> performs the first LBT procedure by using a category-<NUM> ("Cat-<NUM>") LBT procedure to acquire the first COT (i.e., LBT with a random back-off and with a variable size contention window). In such embodiments, the processor <NUM> also performs the directional LBT procedure by using a category-<NUM> ("Cat-<NUM>") LBT procedure (i.e., LBT without random back-off). In some embodiments, performing the first LBT procedure comprises concurrently performing directional LBT procedures on for all configured UE panels.

In some embodiments, the memory <NUM> stores data related to beam switching after LBT procedure. For example, the memory <NUM> may store various parameters, panel/beam configurations, resource assignments, policies, and the like as described above. In certain embodiments, the memory <NUM> also stores program code and related data, such as an operating system or other controller algorithms operating on the apparatus <NUM>.

The transceiver <NUM> communicates with one or more network functions of a mobile communication network via one or more access networks. The transceiver <NUM> operates under the control of the processor <NUM> to transmit messages, data, and other signals and also to receive messages, data, and other signals. For example, the processor <NUM> may selectively activate the transceiver <NUM> (or portions thereof) at particular times in order to send and receive messages.

The transceiver <NUM> includes at least transmitter <NUM> and at least one receiver <NUM>. One or more transmitters <NUM> may be used to provide UL communication signals to a base unit <NUM>, such as the UL transmissions described herein. Similarly, one or more receivers <NUM> may be used to receive DL communication signals from the base unit <NUM>, as described herein. Although only one transmitter <NUM> and one receiver <NUM> are illustrated, the user equipment apparatus <NUM> may have any suitable number of transmitters <NUM> and receivers <NUM>. Further, the transmitter(s) <NUM> and the receiver(s) <NUM> may be any suitable type of transmitters and receivers. In one embodiment, the transceiver <NUM> includes a first transmitter/receiver pair used to communicate with a mobile communication network over licensed radio spectrum and a second transmitter/receiver pair used to communicate with a mobile communication network over unlicensed radio spectrum.

In various embodiments, one or more transmitters <NUM> and/or one or more receivers <NUM> may be implemented and/or integrated into a single hardware component, such as a multi-transceiver chip, a system-on-a-chip, an ASIC, or other type of hardware component. In certain embodiments, one or more transmitters <NUM> and/or one or more receivers <NUM> may be implemented and/or integrated into a multi-chip module. In some embodiments, other components such as the network interface <NUM> or other hardware components/circuits may be integrated with any number of transmitters <NUM> and/or receivers <NUM> into a single chip. In such embodiment, the transmitters <NUM> and receivers <NUM> may be logically configured as a transceiver <NUM> that uses one more common control signals or as modular transmitters <NUM> and receivers <NUM> implemented in the same hardware chip or in a multi-chip module.

<FIG> depicts a network equipment apparatus <NUM> that may be used for beam switching after LBT procedure, according to embodiments of the disclosure. In one embodiment, network equipment apparatus <NUM> may be one implementation of a RAN node, such as the base unit <NUM>, the RAN node <NUM>, or gNB, described above. Furthermore, the base network equipment apparatus <NUM> may include a processor <NUM>, a memory <NUM>, an input device <NUM>, an output device <NUM>, and a transceiver <NUM>.

In some embodiments, the input device <NUM> and the output device <NUM> are combined into a single device, such as a touchscreen. In certain embodiments, the network equipment apparatus <NUM> may not include any input device <NUM> and/or output device <NUM>. In various embodiments, the network equipment apparatus <NUM> may include one or more of: the processor <NUM>, the memory <NUM>, and the transceiver <NUM>, and may not include the input device <NUM> and/or the output device <NUM>.

As depicted, the transceiver <NUM> includes at least one transmitter <NUM> and at least one receiver <NUM>. Here, the transceiver <NUM> communicates with one or more remote units <NUM>. Additionally, the transceiver <NUM> may support at least one network interface <NUM> and/or application interface <NUM>. The application interface(s) <NUM> may support one or more APIs. The network interface(s) <NUM> may support 3GPP reference points, such as Uu, N1, N2 and N3. Other network interfaces <NUM> may be supported, as understood by one of ordinary skill in the art.

For example, the processor <NUM> may be a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or similar programmable controller.

In various embodiments, the network equipment apparatus <NUM> is a RAN node (e.g., gNB) that sends UE configurations and receives measurement reports, as described herein. In such embodiments, the processor <NUM> controls the network equipment apparatus <NUM> to perform the above described behaviors. When operating as a RAN node, the processor <NUM> may include an application processor (also known as "main processor") which manages application-domain and operating system ("OS") functions and a baseband processor (also known as "baseband radio processor") which manages radio functions.

In some embodiments, the memory <NUM> stores data related to beam switching after LBT procedure. For example, the memory <NUM> may store parameters, configurations, resource assignments, policies, and the like, as described above. In certain embodiments, the memory <NUM> also stores program code and related data, such as an operating system or other controller algorithms operating on the remote unit <NUM>.

As another, non-limiting, example, the output device <NUM> may include a wearable display separate from, but communicatively coupled to, the rest of the network equipment apparatus <NUM>, such as a smart watch, smart glasses, a heads-up display, or the like.

The transceiver <NUM> includes at least transmitter <NUM> and at least one receiver <NUM>. One or more transmitters <NUM> may be used to communicate with the UE, as described herein. Similarly, one or more receivers <NUM> may be used to communicate with network functions in the PLMN and/or RAN, as described herein. Although only one transmitter <NUM> and one receiver <NUM> are illustrated, the network equipment apparatus <NUM> may have any suitable number of transmitters <NUM> and receivers <NUM>. Further, the transmitter(s) <NUM> and the receiver(s) <NUM> may be any suitable type of transmitters and receivers.

<FIG> depicts one embodiment of a method <NUM> for beam switching after LBT procedure, according to embodiments of the disclosure. In various embodiments, the method <NUM> is performed by a UE, such as the remote unit <NUM>, the UE <NUM> and/or the user equipment apparatus <NUM>, described above. In some embodiments, the method <NUM> is performed by a processor, such as a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like.

The method <NUM> begins and performs <NUM> a Listen-Before-Talk ("LBT") procedure prior to a first occasion of configured-grant ("CG") resources. The method <NUM> includes performing <NUM> uplink ("UL") transmission of a first transport block ("TB") during the first occasion and using a first beam in response to successful LBT. The method <NUM> includes starting <NUM> a timer in response to the UL transmission. The method <NUM> includes determining <NUM> failure of the UL transmission if no HARQ-ACK feedback is received within the duration of timer. The method <NUM> includes switching <NUM> to a second beam for subsequent UL transmission of the first TB in response to determining failure of the UL transmission. The method <NUM> ends.

The method <NUM> begins and performs <NUM> a first LBT procedure using omni-directional sensing to acquire a first COT. The method <NUM> includes performing <NUM> a first UL transmission of a first TB during the first COT and using a first beam in response to successful LBT. Here, the first UL transmission uses only a first portion of the first COT. The method <NUM> includes performing <NUM> a directional LBT procedure for a second beam to acquire a remaining portion of the first COT. The method <NUM> ends.

Disclosed herein is a first apparatus for beam switching after LBT procedure, according to embodiments of the disclosure. The first apparatus may be implemented by a UE, such as the remote unit <NUM>, the UE <NUM> and/or the user equipment apparatus <NUM>, described above. The first apparatus includes a processor and a transceiver operable on unlicensed spectrum, where the transceiver supports a plurality of UE panels. The processor performs a LBT procedure at a first UE panel prior to a first occasion of CG resources. The processor performs UL transmission of a first TB during the first occasion and using the first UE panel in response to successful LBT and starts a timer in response to the UL transmission. The processor determines that failure of the UL transmission has occurred in response to not receiving any HARQ-ACK feedback within the duration of timer and switches to a second UE panel for subsequent UL transmission of the first TB in response to determining that failure of the UL transmission has occurred. Note that while the first apparatus is described in terms of performing a LBT procedure and transmission for a set of "UE panels," in other embodiments the LBT procedure and transmission may be performed for a set of "beams.

In some embodiments, the second UE panel is associated with the same CG resources as the first UE panel. In such embodiments, the subsequent UL transmission is performed using the same time-frequency resource as the first occasion of CG resources. In other embodiments, each TX UE panel is associated with different CG resources. In such embodiments, the subsequent UL transmission is performed using a different time-frequency resource than the first occasion of CG resources. In certain embodiments, performing the subsequent UL transmission includes selecting a CG resource having a same TB size as the first occasion of CG resources.

In some embodiments, the timer comprises either a CG retransmission timer or a panel failure timer that is different from the CG retransmission timer. In certain embodiments, the panel failure timer is associated with a certain channel access priority class. In some embodiments, the UL transmission during the first occasion is associated with a first HARQ process. In such embodiments, performing UL transmission during the second occasion and using the second UE panel includes reusing the first HARQ process.

In some embodiments, performing the LBT procedure includes performing a clear channel assessment for a plurality of sensing UE panels. In such embodiments, performing the UL transmission of the first TB during the first occasion includes selecting a single one of the plurality of TX UE panels and transmitting the first TB using the selected TX UE panel. In certain embodiments, the single one of the plurality of TX UE panels is selected based on a lowest energy detection value from the clear channel assessments of the sensing UE panel. In such embodiments, a QCL type-D relationship exists between the plurality of sensing UE panels and the plurality of TX UE panels.

In some embodiments, performing the LBT procedure includes performing a clear channel assessment for a plurality of sensing UE panels. In such embodiments, performing the UL transmission of the first TB further includes transmitting the first TB using at least one additional TX UE panel from the plurality of sensing UE panels for which LBT is successful, where each TX UE panel is associated with different CG resources. In certain embodiments, the processor further terminates retransmission of the first TB in response to receiving at least one HARQ-ACK feedback and flushes all HARQ buffers associated with transmission of the first TB.

In some embodiments, the UL transmission during the first occasion is accompanied by UCI identifying the UE panel used for transmission on the CG resource. In some embodiments, the value of the timer corresponds to a channel access priority class for the UL transmission. In some embodiments, the processor further terminates the timer in response to receiving at least one HARQ-ACK feedback for the first TB and flushes a HARQ buffer associated with transmission of the first TB in response to receiving the HARQ-ACK feedback for the first TB.

Disclosed herein is a first method for beam switching after LBT procedure, according to embodiments of the disclosure. The first method may be performed by a UE, such as the remote unit <NUM>, the UE <NUM> and/or the user equipment apparatus <NUM>, described above. The first method includes receiving a first message containing a first indication of an access mode of a UE, where the UE is connected to a non-public radio cell, and transmitting a second message specifying at least one measurement configuration from the RAN node to the UE. The first method includes performing a LBT procedure prior to a first occasion of CG resources and performing UL transmission of a first TB during the first occasion and using a first beam in response to successful LBT. The first method includes starting a timer in response to the UL transmission, determining that failure of the UL transmission has occurred in response to not receiving any HARQ-ACK feedback within the duration of timer, and switching to a second beam for subsequent UL transmission of the first TB in response to determining that failure of the UL transmission has occurred. Note that while the first method is described in terms of performing a LBT procedure and transmission for a set of "beams," in other embodiments the LBT procedure and transmission may be performed for a set of "UE panel.

In some embodiments, the UE is configured with a multiple sensing beams. In such embodiments, the LBT procedure is performed using a first sensing beam, where switching to the second beam includes switching from the first sensing beam to a second sensing beam. In some embodiments, the UE is configured with a multiple TX beams. In such embodiments, the UL transmission of a first TB is performed for a first TX beam, where switching to the second beam includes switching from the first TX beam to a second TX beam.

In some embodiments, the second beam is associated with the same CG resources as the first beam. In such embodiments, the subsequent UL transmission is performed using the same time-frequency resource as the first occasion of CG resources. In other embodiments, each TX beam is associated with different CG resources. In such embodiments, the subsequent UL transmission is performed using a different time-frequency resource than the first occasion of CG resources. In certain embodiments, performing the subsequent UL transmission includes selecting a CG resource having a same TB size as the first occasion of CG resources.

In some embodiments, the timer comprises either a CG retransmission timer or a beam failure timer that is different from the CG retransmission timer. In certain embodiments, the beam failure timer is associated with a certain channel access priority class. In some embodiments, the UL transmission during the first occasion is associated with a first HARQ process. In such embodiments, performing UL transmission during the second occasion and using the second beam comprises reusing the first HARQ process.

In some embodiments, performing the LBT procedure includes performing a clear channel assessment for a plurality of sensing beams. In such embodiments, performing the UL transmission of the first TB during the first occasion includes selecting a single one of the plurality of TX beams and transmitting the first TB using the selected TX beam. In certain embodiments, the single one of the plurality of TX beams is selected based on a lowest energy detection value from the clear channel assessments of the sensing beam. In such embodiments, a QCL type-D relationship exists between the plurality of sensing beams and the plurality of TX beams.

In some embodiments, performing the LBT procedure includes performing a clear channel assessment for a plurality of sensing beams, wherein performing the UL transmission of the first TB further includes transmitting the first TB using at least one additional TX beam from the plurality of sensing beams for which LBT is successful, where each TX beam is associated with different CG resources. In certain embodiments, the first method further includes terminating retransmission of the first TB in response to receiving at least one HARQ-ACK feedback and flushing all HARQ buffers associated with transmission of the first TB.

In some embodiments, the UL transmission during the first occasion is accompanied by UCI, the UCI identifying the beam used for transmission on the CG resource. In some embodiments, the value of the timer corresponds to a channel access priority class for the UL transmission. In some embodiments, the first method further includes terminating the timer in response to receiving at least one HARQ-ACK feedback for the first TB and flushing a HARQ buffer associated with transmission of the first TB in response to receiving the HARQ-ACK feedback for the first TB.

Disclosed herein is a second apparatus for beam switching after LBT procedure, according to embodiments of the disclosure. The second apparatus may be implemented by a UE, such as the remote unit <NUM>, the UE <NUM> and/or the user equipment apparatus <NUM>, described above. The second apparatus includes a processor and a transceiver that is operable on unlicensed spectrum, wherein the transceiver supports a plurality of UE panels. The processor performs a first LBT procedure using omni-directional sensing to acquire a first COT and performs a first UL transmission of a first TB during the first COT and using a first UE panel in response to successful LBT. Here, the first UL transmission uses a first portion of the first COT [i.e., does not use the entirety of the first COT]. The processor performs a directional LBT procedure for a second UE panel to acquire a remaining portion of the first COT. Note that while the second apparatus is described in terms of performing a LBT procedure and transmission for a set of "UE panels," in other embodiments the LBT procedure and transmission may be performed for a set of "beams.

In some embodiments, performing the first LBT procedure comprises using a category-<NUM> ("Cat-<NUM>") LBT procedure to acquire the first COT, wherein performing the directional LBT procedure comprises using a category-<NUM> ("Cat-<NUM>") LBT procedure. In some embodiments, performing the first LBT procedure comprises concurrently performing directional LBT procedures on for all configured UE panels.

Disclosed herein is a second method for beam switching after LBT procedure, according to embodiments of the disclosure. The second method may be performed by a UE, such as the remote unit <NUM>, the UE <NUM> and/or the user equipment apparatus <NUM>, described above. The second method includes performing a first LBT procedure using omni-directional sensing to acquire a first COT and performing a first UL transmission of a first TB during the first COT and using a first beam in response to successful LBT, wherein the first UL transmission uses a first portion of the first COT [i.e., does not use the entirety of the first COT]. The second method includes performing a directional LBT procedure for a second beam to acquire a remaining portion of the first COT. Note that while the second method is described in terms of performing a LBT procedure and transmission for a set of "beams," in other embodiments the LBT procedure and transmission may be performed for a set of "UE panels.

In some embodiments, performing the first LBT procedure comprises using a category-<NUM> ("Cat-<NUM>") LBT procedure to acquire the first COT, wherein performing the directional LBT procedure comprises using a category-<NUM> ("Cat-<NUM>") LBT procedure. In some embodiments, performing the first LBT procedure comprises concurrently performing directional LBT procedures on for all configured beams.

Claim 1:
A method at a User Equipment, UE, the method (<NUM>) comprising:
performing (<NUM>) a Listen-Before-Talk, LBT, procedure prior to a first occasion of configured-grant, CG, resources;
performing (<NUM>) uplink, UL, transmission of a first transport block, TB, during the first occasion and using a first beam in response to successful LBT; said method characterised by:
starting (<NUM>) a timer in response to the UL transmission;
determining (<NUM>) failure of the UL transmission if no HARQ-ACK feedback is received within the duration of timer; and
switching (<NUM>) to a second beam for subsequent UL transmission of the first TB in response to determining failure of the UL transmission.