CONNECTIONS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to United States Provisional Patent Application Number 63/309,922 entitled “LISTEN BEFORE TALK FAILURE PROCEDURES FOR SIDELINK CONNECTIONS” and fried on Feb. 14, 2022, for Joachim Lohr, which is incorporated herein by reference.

FIELD

[0002] The subject matter disclosed herein relates generally to wireless communications and more particularly relates to listen before talk failure procedures for sidelink connections.

BACKGROUND

[0003] In certain wireless communication systems, a User Equipment device (“UE”) is able to connect with a fifth-generation (“5G”) core network (i.e., “5GC”) in a Public Land Mobile Network (“PLMN”). In wireless networks, channel access in both downlink and uplink rely on listen before talk procedures.

BRIEF SUMMARY

[0004] Disclosed are procedures for listen before talk failure procedures for sidelink connections. The procedures may be implemented by apparatus, systems, methods, and/or computer program products.

[0005] In one embodiment, a first apparatus includes a memory and a processor coupled to the memory. In one embodiment, the processor is configured to cause the apparatus to perform listen before talk (“LBT”) for a sidelink transmission, the sidelink transmission addressed to a first destination identity. In one embodiment, the processor is configured to cause the apparatus to detect an LBT failure for a first resource pool associated with the sidelink transmission, deactivate the first resource pool for sidelink transmissions in response to determining that the detected LBT failure satisfies a predefined failure threshold for the resource pool, and switch to a second resource pool for sidelink transmissions.

[0006] In one embodiment, a first method includes performing LBT for a sidelink transmission, the sidelink transmission addressed to a first destination identity. In one embodiment, the first method includes detecting an LBT failure for a first resource pool associated with the sidelink transmission, deactivating the first resource pool for sidelink transmissions in response to determining that the detected LBT failure satisfies a predefined failure threshold for the resource pool, and switching to a second resource pool for sidelink transmissions.

[0007] In one embodiment, a second apparatus includes a memory and a processor coupled to the memory. In one embodiment, the processor is configured to cause the apparatus to perform LBT for a sidelink transmission, the sidelink transmission addressed to a first destination identity, detect an LBT failure associated with the sidelink transmission, increment a counter in response to the detected LBT failure, the counter associated with the first destination identity, and deactivate sidelink transmissions to the first destination identity in response to the counter satisfying a predefined threshold.

[0008] In one embodiment, a second method includes performing LBT for a sidelink transmission, the sidelink transmission addressed to a first destination identity. In one embodiment, the second method includes detecting an LBT failure associated with the sidelink transmission, incrementing a counter in response to the detected LBT failure, the counter associated with the first destination identity, and deactivating sidelink transmissions to the first destination identity in response to the counter satisfying a predefined threshold.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] A more particular description of the embodiments briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings. Understanding that these drawings depict only some embodiments and are not therefore to be considered to be limiting of scope, the embodiments will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which:

[0010] Figure 1 is a schematic block diagram illustrating one embodiment of a wireless communication system for listen before talk failure procedures for sidelink connections;

[0011] Figure 2 depicts one example embodiment of channel access in NR-U;

[0012] Figure 3 is a diagram illustrating one embodiment of a user equipment apparatus that may be used for listen before talk failure procedures for sidelink connections;

[0013] Figure 4 is a diagram illustrating one embodiment of a network equipment apparatus that may be used for listen before talk failure procedures for sidelink connections;

[0014] Figure 5 is a flowchart diagram illustrating one embodiment of a method for listen before talk failure procedures for sidelink connections; and

[0015] Figure 6 is a flowchart diagram illustrating one embodiment of a method for listen before talk failure procedures for sidelink connections. DETAILED DESCRIPTION

[0016] As will be appreciated by one skilled in the art, aspects of the embodiments may be embodied as a system, apparatus, method, or program product. Accordingly, embodiments may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects.

[0017] For example, the disclosed embodiments may be implemented as a hardware circuit comprising custom very-large-scale integration (“VLSI”) circuits or gate arrays, off-the-shelf semiconductors such as logic chips, transistors, or other discrete components. The disclosed embodiments may also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices, or the like. As another example, the disclosed embodiments may include one or more physical or logical blocks of executable code which may, for instance, be organized as an object, procedure, or function.

[0018] Furthermore, embodiments may take the form of a program product embodied in one or more computer readable storage devices storing machine readable code, computer readable code, and/or program code, referred hereafter as code. The storage devices may be tangible, non- transitory, and/or non-transmission. The storage devices may not embody signals. In a certain embodiment, the storage devices only employ signals for accessing code.

[0019] Any combination of one or more computer readable medium may be utilized. The computer readable medium may be a computer readable storage medium. The computer readable storage medium may be a storage device storing the code. The storage device may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, holographic, micromechanical, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.

[0020] More specific examples (a non-exhaustive list) of the storage device would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random-access memory (“RAM”), a read-only memory (“ROM”), an erasable programmable read-only memory (“EPROM” or Flash memory), a portable compact disc readonly memory (“CD-ROM”), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device.

[0021] 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. The code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. 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”)).

[0022] Furthermore, the described features, structures, or characteristics of the embodiments may be combined in any suitable manner. In the following description, numerous specific details are provided, such as examples of programming, software modules, user selections, network transactions, database queries, database structures, hardware modules, hardware circuits, hardware chips, etc., to provide a thorough understanding of embodiments. One skilled in the relevant art will recognize, however, that embodiments may be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of an embodiment.

[0023] Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment, but mean “one or more but not all embodiments” unless expressly specified otherwise. The terms “including,” “comprising,” “having,” and variations thereof mean “including but not limited to,” unless expressly specified otherwise. An enumerated listing of items does not imply that any or all of the items are mutually exclusive, unless expressly specified otherwise. The terms “a,” “an,” and “the” also refer to “one or more” unless expressly specified otherwise.

[0024] As used herein, a list with a conjunction of “and/or” includes any single item in the list or a combination of items in the list. For example, a list of A, B and/or C includes only A, only B, only C, a combination of A and B, a combination of B and C, a combination of A and C or a combination of A, B and C. As used herein, a list using the terminology “one or more of’ includes any single item in the list or a combination of items in the list. For example, one or more of A, B and C includes only A, only B, only C, a combination of A and B, a combination of B and C, a combination of A and C or a combination of A, B and C. As used herein, a list using the terminology “one of’ includes one and only one of any single item in the list. For example, “one of A, B and C” includes only A, only B or only C and excludes combinations of A, B and C. As used herein, “a member selected from the group consisting of A, B, and C,” includes one and only one of A, B, or C, and excludes combinations of A, B, and C. As used herein, “a member selected from the group consisting of A, B, and C and combinations thereof’ includes only A, only B, only C, a combination of A and B, a combination of B and C, a combination of A and C or a combination of A, B and C.

[0025] Aspects of the embodiments are described below with reference to schematic flowchart diagrams and/or schematic block diagrams of methods, apparatuses, systems, and program products according to embodiments. It will be understood that each block of the schematic flowchart diagrams and/or schematic block diagrams, and combinations of blocks in the schematic flowchart diagrams and/or schematic block diagrams, can be implemented by code. This code may be provided to a processor of a general-purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart diagrams and/or block diagrams.

[0026] The code may also be stored in a storage device that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the storage device produce an article of manufacture including instructions which implement the function/act specified in the flowchart diagrams and/or block diagrams.

[0027] 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.

[0028] The flowchart diagrams and/or block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of apparatuses, systems, methods, and program products according to various embodiments. In this regard, each block in the flowchart diagrams and/or block diagrams may represent a module, segment, or portion of code, which includes one or more executable instructions of the code for implementing the specified logical function(s). [0029] It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the Figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. Other steps and methods may be conceived that are equivalent in function, logic, or effect to one or more blocks, or portions thereof, of the illustrated Figures.

[0030] Although various arrow types and line types may be employed in the flowchart and/or block diagrams, they are understood not to limit the scope of the corresponding embodiments. Indeed, some arrows or other connectors may be used to indicate only the logical flow of the depicted embodiment. For instance, an arrow may indicate a waiting or monitoring period of unspecified duration between enumerated steps of the depicted embodiment. It will also be noted that each block of the block diagrams and/or flowchart diagrams, and combinations of blocks in the block diagrams and/or flowchart diagrams, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and code.

[0031] The description of elements in each figure may refer to elements of proceeding figures. Like numbers refer to like elements in all figures, including alternate embodiments of like elements.

[0032] Generally, the present disclosure describes systems, methods, and apparatus for listen before talk failure procedures for sidelink (“SL”) connections. In certain embodiments, the methods may be performed using computer code embedded on a computer-readable medium. In certain embodiments, an apparatus or system may include a computer-readable medium containing computer-readable code which, when executed by a processor, causes the apparatus or system to perform at least a portion of the below described solutions.

[0033] In one embodiment, when a UE detects consistent uplink LBT failures, it can take various actions. The detection of an LBT failure may be per bandwidth part (“BWP”) and based on all uplink transmissions within this BWP. As described in more detail below, when consistent uplink LBT failures are detected on secondary cell(s) (“SCell(s)”), the UE reports this to the corresponding gNB via medium access control (“MAC”) control element (“CE”) on a different serving cell than the SCell(s) where the failures were detected. If no resources are available to transmit the MAC CE, a scheduling request (“SR”) can be transmitted by the UE. When consistent uplink LBT failures are detected on special cell (“SpCell”), the UE switches to another UL BWP with configured random access channel (“RACH”) resources on that cell, initiates RACH, and reports the failure via MAC CE. When multiple UL BWPs are available for switching, it is up to the UE implementation which one to select. For primary secondary cell (“PSCell”), if consistent uplink LBT failures are detected on all the UL BWPs with configured RACH resources, the UE declares secondary cell group (“SCG”) radio link failure (“RLF”) and reports the failure to the MN via SCGFailurelnformation. For primary cell (“PCell”), if the uplink LBT failures are detected on all the UL BWP(s) with configured RACH resources, the UE declares RLF.

[0034] In one embodiment, consistent LBT failure detection is per UL BWP based on all uplink transmissions within this BWP. Upon declaring a consistent uplink LBT failure for a serving cell UE does the corresponding actions. For cases when sidelink is operated on a cell configured with shared spectrum and if UE would detect/declare consistent LBT failure per SL BWP based on all SL transmissions within this BWP - as specified for the Uu interface - it may happen that consistent LBT failure is triggered even though the congestion/LBT issue occurs only for a specific resource pool or SL destination. Since a SL UE may be in communication with multiple different SL UEs residing at different locations, the channel conditions could be very different among the different SL connections.

[0035] In one embodiment, consistent LBT failures are detected per sidelink destination. A UE maintains an LBT counter/timer for each destination separately. Upon declaring a consistent LBT failure for a destination, the UE stops sidelink transmissions to that destination. In one implementation, the UE suspends SL logical channels (“LCHs”) associated with a destination for which consistent LBT failure was triggered/declared.

[0036] In a first embodiment, a UE measures or counts LBT failure per destination ID. According to one implementation a UE/MAC layer of a sidelink UE counts LBT failure separately for each destination/connection it is in communication with. According to one implementation of this embodiment, a UE (e.g., a transmitting (“Tx”) UE) deactivates sidelink transmissions to a specific destination for cases when the LBT counter has reached or exceeded a predefined threshold for that destination/pair of source Layer 2 and destination Layer 2 IDs. In one implementation, Tx UE doesn’t consider the SL LCHs associated with that destination for future LCP procedures/SL transmissions.

[0037] According to second embodiment, consistent LBT failure is declared/detected per resource pool, e.g., per Tx resource pool. According to one implementation of the embodiment, a UE declares consistent LBT failure for a Tx resource pool if a predefined number of LBT failures has been exceeded/met for sidelink transmission within the resource pool. The Tx UE may autonomously deactivate a resource pool for cases that a predefined maximum number of LBT failures has been exceeded/met for a resource pool and switch to a different resource pool. If consistent LBT failure has been declared for all SL transmission resource pools within a SL BWP or a SL serving cell, the Tx UE indicates consistent LBT failure to upper layer in one implementation.

[0038] Figure 1 depicts a wireless communication system 100 for listen before talk failure procedures for sidelink connections, according to embodiments of the disclosure. In one embodiment, the wireless communication system 100 includes at least one remote unit 105, a Fifth -Generation Radio Access Network (“5G-RAN”) 115, and a mobile core network 140. The 5G-RAN 115 and the mobile core network 140 form a mobile communication network. The 5G- RAN 115 may be composed of a 3GPP access network 120 containing at least one cellular base unit 121 and/or a non-3GPP access network 130 containing at least one access point 131. The remote unit 105 communicates with the 3GPP access network 120 using 3GPP communication links 123 and/or communicates with the non-3GPP access network 130 using non-3GPP communication links 133. Even though a specific number of remote units 105, 3GPP access networks 120, cellular base units 121, 3GPP communication links 123, non-3GPP access networks 130, access points 131, non-3GPP communication links 133, and mobile core networks 140 are depicted in Figure 1, one of skill in the art will recognize that any number of remote units 105, 3 GPP access networks 120, cellular base units 121, 3 GPP communication links 123, non-3GPP access networks 130, access points 131, non-3GPP communication links 133, and mobile core networks 140 may be included in the wireless communication system 100.

[0039] In one implementation, the RAN 120 is compliant with the 5G system specified in the Third Generation Partnership Project (“3GPP”) specifications. For example, the RAN 120 may be a NG-RAN, implementing NR RAT and/or LTE RAT. In another example, the RAN 120 may include non-3GPP RAT (e.g., Wi-Fi® or Institute of Electrical and Electronics Engineers (“IEEE”) 802.11-family compliant WLAN). In another implementation, the RAN 120 is compliant with the LTE system specified in the 3GPP specifications. More generally, however, the wireless communication system 100 may implement some other open or proprietary communication network, for example Worldwide Interoperability for Microwave Access (“WiMAX”) or IEEE 802.16-family standards, among other networks. The present disclosure is not intended to be limited to the implementation of any particular wireless communication system architecture or protocol.

[0040] In one embodiment, the remote units 105 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. In some embodiments, the remote units 105 include wearable devices, such as smart watches, fitness bands, optical head-mounted displays, or the like. Moreover, the remote units 105 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 105 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 105 may include a terminal equipment (“TE”) and/or be embedded in an appliance or device (e.g., a computing device, as described above).

[0041] In one embodiment, the remote units 105 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. In some embodiments, the remote units 105 include wearable devices, such as smart watches, fitness bands, optical head-mounted displays, or the like. Moreover, the remote units 105 may be referred to as 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.

[0042] The remote units 105 may communicate directly with one or more of the cellular base units 121 in the 3GPP access network 120 via uplink (“UL”) and downlink (“DL”) communication signals. Furthermore, the UL and DL communication signals may be carried over the 3GPP communication links 123. Similarly, the remote units 105 may communicate with one or more access points 131 in the non-3GPP access network(s) 130 via UL and DL communication signals carried over the non-3GPP communication links 133. Here, the access networks 120 and 130 are intermediate networks that provide the remote units 105 with access to the mobile core network 140.

[0043] In some embodiments, the remote units 105 communicate with a remote host (e.g., in the data network 150 or in the data network 160) via a network connection with the mobile core network 140. For example, an application 107 (e.g., web browser, media client, telephone and/or Voice-over-Internet -Protocol (“VoIP”) application) in a remote unit 105 may trigger the remote unit 105 to establish a protocol data unit (“PDU”) session (or other data connection) with the mobile core network 140 via the 5G-RAN 115 (i.e., via the 3GPP access network 120 and/or non- 3GPP network 130). The mobile core network 140 then relays traffic between the remote unit 105 and the remote host using the PDU session. The PDU session represents a logical connection between the remote unit 105 and a User Plane Function (“UPF”) 141.

[0044] In order to establish the PDU session (or PDN connection), the remote unit 105 must be registered with the mobile core network 140 (also referred to as “attached to the mobile core network” in the context of a Fourth Generation (“4G”) system). Note that the remote unit 105 may establish one or more PDU sessions (or other data connections) with the mobile core network 140. As such, the remote unit 105 may have at least one PDU session for communicating with the packet data network 150. Additionally - or alternatively - the remote unit 105 may have at least one PDU session for communicating with the packet data network 160. The remote unit 105 may establish additional PDU sessions for communicating with other data networks and/or other communication peers.

[0045] In the context of a 5G 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 105 and a specific Data Network (“DN”) through the UPF 131. 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 5G QoS Identifier (“5QI”).

[0046] In the context of a 4G/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 105 and a Packet Gateway (“PGW”, not shown) in the mobile core network 130. 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”).

[0047] As described in greater detail below, the remote unit 105 may use a first data connection (e.g., PDU Session) established with the first mobile core network 130 to establish a second data connection (e.g., part of a second PDU session) with the second mobile core network 140. When establishing a data connection (e.g., PDU session) with the second mobile core network 140, the remote unit 105 uses the first data connection to register with the second mobile core network 140.

[0048] The cellular base units 121 may be distributed over a geographic region. In certain embodiments, a cellular base unit 121 may also be referred to as an access terminal, 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 5G/NRNode B (“gNB”), a Home Node-B, a Home Node-B, a relay node, a device, or by any other terminology used in the art. The cellular base units 121 are generally part of a radio access network (“RAN”), such as the 3GPP access network 120, that may include one or more controllers communicably coupled to one or more corresponding cellular base units 121. 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 cellular base units 121 connect to the mobile core network 140 via the 3GPP access network 120.

[0049] The cellular base units 121 may serve a number of remote units 105 within a serving area, for example, a cell or a cell sector, via a 3GPP wireless communication link 123. The cellular base units 121 may communicate directly with one or more of the remote units 105 via communication signals. Generally, the cellular base units 121 transmit DL communication signals to serve the remote units 105 in the time, frequency, and/or spatial domain. Furthermore, the DL communication signals may be carried over the 3GPP communication links 123. The 3GPP communication links 123 may be any suitable carrier in licensed or unlicensed radio spectrum. The 3GPP communication links 123 facilitate communication between one or more of the remote units 105 and/or one or more of the cellular base units 121. Note that during NR operation on unlicensed spectrum (referred to as “NR-U”), the base unit 121 and the remote unit 105 communicate over unlicensed (i.e., shared) radio spectrum.

[0050] The non-3GPP access networks 130 may be distributed over a geographic region. Each non-3GPP access network 130 may serve a number of remote units 105 with a serving area. An access point 131 in a non-3GPP access network 130 may communicate directly with one or more remote units 105 by receiving UL communication signals and transmitting DL communication signals to serve the remote units 105 in the time, frequency, and/or spatial domain. Both DL and UL communication signals are carried over the non-3GPP communication links 133. The 3GPP communication links 123 and non-3GPP communication links 133 may employ different frequencies and/or different communication protocols. In various embodiments, an access point 131 may communicate using unlicensed radio spectrum. The mobile core network 140 may provide services to a remote unit 105 via the non-3GPP access networks 130, as described in greater detail herein.

[0051] In some embodiments, a non-3GPP access network 130 connects to the mobile core network 140 via an interworking entity 135. The interworking entity 135 provides an interworking between the non-3GPP access network 130 and the mobile core network 140. The interworking entity 135 supports connectivity via the “N2” and “N3” interfaces. As depicted, both the 3GPP access network 120 and the interworking entity 135 communicate with the AMF 143 using a “N2” interface. The 3GPP access network 120 and interworking entity 135 also communicate with the UPF 141 using a “N3” interface. While depicted as outside the mobile core network 140, in other embodiments the interworking entity 135 may be a part of the core network. While depicted as outside the non-3GPP RAN 130, in other embodiments the interworking entity 135 may be a part of the non-3GPP RAN 130.

[0052] In certain embodiments, a non-3GPP access network 130 may be controlled by an operator of the mobile core network 140 and may have direct access to the mobile core network 140. Such a non-3GPP AN deployment is referred to as a “trusted non-3GPP access network.” A non-3GPP access network 130 is considered as “trusted” when it is operated by the 3GPP operator, or a trusted partner, and supports certain security features, such as strong air-interface encryption. In contrast, a non-3GPP AN deployment that is not controlled by an operator (or trusted partner) of the mobile core network 140, does not have direct access to the mobile core network 140, or does not support the certain security features is referred to as a “non-trusted” non-3GPP access network. An interworking entity 135 deployed in a trusted non-3GPP access network 130 may be referred to herein as a Trusted Network Gateway Function (“TNGF”). An interworking entity 135 deployed in a non-trusted non-3GPP access network 130 may be referred to herein as a non-3GPP interworking function (“N3IWF”). While depicted as a part of the non-3GPP access network 130, in some embodiments the N3IWF may be a part of the mobile core network 140 or may be located in the data network 150.

[0053] In one embodiment, the mobile core network 140 is a 5G core (“5GC”) or the evolved packet core (“EPC”), which may be coupled to a data network 150, like the Internet and private data networks, among other data networks. A remote unit 105 may have a subscription or other account with the mobile core network 140. Each mobile core network 140 belongs to a single public land mobile network (“PLMN”). The present disclosure is not intended to be limited to the implementation of any particular wireless communication system architecture or protocol.

[0054] The mobile core network 140 includes several network functions (“NFs”). As depicted, the mobile core network 140 includes at least one UPF (“UPF”) 141. The mobile core network 140 also includes multiple control plane functions including, but not limited to, an Access and Mobility Management Function (“AMF”) 143 that serves the 5G-RAN 115, a Session Management Function (“SMF”) 145, a Policy Control Function (“PCF”) 146, an Authentication Server Function (“AUSF”) 147, a Unified Data Management (“UDM”) and Unified Data Repository function (“UDR”). [0055] The UPF(s) 141 is responsible for packet routing and forwarding, packet inspection, QoS handling, and external PDU session for interconnecting Data Network (“DN”), in the 5G architecture. The AMF 143 is responsible for termination ofNAS signaling, NAS ciphering & integrity protection, registration management, connection management, mobility management, access authentication and authorization, security context management. The SMF 145 is responsible for session management (i.e., session establishment, modification, release), remote unit (i.e., UE) IP address allocation & management, DL data notification, and traffic steering configuration for UPF for proper traffic routing.

[0056] The PCF 146 is responsible for unified policy framework, providing policy rules to CP functions, access subscription information for policy decisions in UDR. The AUSF 147 acts as an authentication server.

[0057] The UDM is responsible for generation of Authentication and Key Agreement (“AKA”) credentials, user identification handling, access authorization, subscription management. The UDR is a repository of subscriber information and can be used to service a number of network functions. For example, the UDR may store subscription data, policy-related data, subscriber- related data that is permitted to be exposed to third party applications, and the like. In some embodiments, the UDM is co-located with the UDR, depicted as combined entity “UDM/UDR” 149.

[0058] In various embodiments, the mobile core network 140 may also include an Network Exposure Function (“NEF”) (which is responsible for making network data and resources easily accessible to customers and network partners, e.g., via one or more APIs), a Network Repository Function (“NRF”) (which provides NF service registration and discovery, enabling NFs to identify appropriate services in one another and communicate with each other over Application Programming Interfaces (“APIs”)), or other NFs defined for the 5GC. In certain embodiments, the mobile core network 140 may include an authentication, authorization, and accounting (“AAA”) server.

[0059] In various embodiments, the mobile core network 140 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 140 optimized for a certain traffic type or communication service. A network instance may be identified by a S-NSSAI, while a set of network slices for which the remote unit 105 is authorized to use is identified by NS SAI. In certain embodiments, the various network slices may include separate instances of network functions, such as the SMF and UPF 141. In some embodiments, the different network slices may share some common network functions, such as the AMF 143. The different network slices are not shown in Figure 1 for ease of illustration, but their support is assumed.

[0060] Although specific numbers and types of network functions are depicted in Figure 1 , one of skill in the art will recognize that any number and type of network functions may be included in the mobile core network 140. Moreover, where the mobile core network 140 comprises an EPC, the depicted network functions may be replaced with appropriate EPC entities, such as an MME, S-GW, P-GW, HSS, and the like.

[0061] While Figure 1 depicts components of a 5G RAN and a 5G core network, the described embodiments for using a pseudonym for access authentication over non-3GPP access apply to other types of communication networks and RATs, including IEEE 802. 11 variants, GSM, GPRS, UMTS, LTE variants, CDMA 2000, Bluetooth, ZigBee, Sigfoxx, and the like. For example, in an 4G/LTE variant involving an EPC, the AMF 143 may be mapped to an MME, the SMF mapped to a control plane portion of a PGW and/or to an MME, the UPF 141 may be mapped to an SGW and a user plane portion of the PGW, the UDM/UDR 149 may be mapped to an HSS, etc.

[0062] As depicted, a remote unit 105 (e.g., a UE) may connect to the mobile core network (e.g., to a 5G mobile communication network) via two types of accesses: (1) via 3GPP access network 120 and (2) via a non-3GPP access network 130. The first type of access (e.g., 3GPP access network 120) uses a 3GPP-defmed type of wireless communication (e.g., NG-RAN) and the second type of access (e.g., non-3GPP access network 130) uses a non-3GPP -defined type of wireless communication (e.g., WLAN). The 5G-RAN 115 refers to any type of 5G access network that can provide access to the mobile core network 140, including the 3GPP access network 120 and the non-3GPP access network 130.

[0063] In the following the term eNB/gNB is used for the base station but it is replaceable by any other radio access node, e.g., BS, eNB, gNB, AP, NR, or the like. Further, the proposed solutions are described mainly in the context of 5GNR. However, the proposed solutions may also be applicable to other mobile communication systems supporting services targeted by the Study Item on NR IIoT.

[0064] Figure 2 depicts an example of channel access in NR-U. In NR-U, channel access in both downlink and uplink relies on the LBT. A gNB and/or a UE first sense the channel to find out there is no on-going communications prior to any transmission. When a communication channel is a wide bandwidth unlicensed carrier 202, the channel clear assessment (“CCA”) procedure relies on detecting the energy level on multiple sub-bands 204 of the communications channel as shown in Figure 2. No beamforming is considered for LBT in NR-U in Rel. 16 and only omni-directional LBT is assumed.

[0065] NR-U RAN2#107bis made the following agreements with respects to LBT failure handling: a. MAC relies on reception of a notification of UL LBT failure from the physical layer to detect a consistent UL LBT failure. b. The UE switches to another BWP and initiates RACH upon declaration of consistent LBT failure on PCell or PSCell if there is another BWP with configured RACH resources. c. The UE shall perform RLF recovery if the consistent UL LBT failure was detected on the PCell and UL LBT failure was detected on “N” possible BWP. d. When consistent uplink LBT failures are detected on the PSCell, the UE informs MN via the SCG failure information procedure after detecting a consistent UL LBT failure on “N” BWPs. e. “N” is the number of configured BWPs with configured PRACH resources. If N is larger than one it is up to the UE implementation which BWP the UE selects. f. When consistent uplink LBT failures are detected on an SCell, a new MAC CE to report this to the node where SCell belongs to is used. FFS whether the MAC CE can be used to report failure on PCell.

[0066] In case of consistent LBT failure, a UE is, according to the latest RAN2 agreements, allowed to autonomously switch the UL BWP. The motivation for these agreements is that other UL BWP(s) of the NR-U cell may not be subject to large number of LBT failures, e.g., different LBT sub-bands are used for different UL BWP(s). In the following some excerpt from latest CR to TS38.321 is presented showing how the UE behavior for the case of consistent LBT failure is implemented.

[0067] For LTE enhanced licensed assisted access (“eLAA”), autonomous uplink (“AUL”) transmissions can be enabled through a combination of radio resource control (“RRC”) signaling and an activation message conveyed by a downlink control information (“DCI”) in a physical control channel. The RRC configuration includes subframes in which the UE is allowed to transmit autonomously, as well as eligible hybrid automatic repeat request (“HARQ”) process IDs. The activation message includes the resource block assignment (“RBA”) and modulation and coding scheme (“MCS”), from which the UE is able to determine the transport block size for any AUL transmission.

[0068] It may be possible to autonomously retransmit data pertaining to a transport block that has not been received correctly by the evolved node B (“eNB”). For this purpose, the UE monitors downlink feedback information (AUL-DFI), which can be transmitted by the eNB and includes HARQ-ACK information for the AUL-enabled HARQ process IDs. In case the UE detects a NACK message, it may try to autonomously access the channel for a retransmission of the same transport block in the corresponding HARQ process. As a safe-guard against errors, an autonomous uplink transmission includes at least the HARQ process ID and a new data indicator (“NDI”) accompanying the physical uplink shared channel (“PUSCH”), e.g., AUL-UCI.

[0069] It is also possible for the eNB to transmit an uplink grant through a DCI that assigns uplink resources for a retransmission of the same transport block using the indicated HARQ process. It is further possible that the eNB transmits an uplink grant through a DCI that assigns uplink resources for a transmission of a new transport block using the indicated HARQ process. In other words, even though a HARQ process ID can be eligible for AUL transmissions, the eNB still has access to this process at any time through a scheduling grant (DCI). In general, if the UE detects a grant for an UL transmission for a subframe that is eligible for AUL (according to the RRC configuration), it will follow the received grant and will not perform an AUL transmission in that subframe.

Table 1: Fields for AUL-UCI

[0070] Various 3GPP agreements for channel occupancy time (“COT”) sharing include: i. Sharing of a UE-initiated channel occupancy (either CG-PUSCH or scheduled UL) with gNB is supported, such that the gNB is allowed to transmit control/broadcast signals/channels for any UEs as long as the transmission contains transmissions for the UE that initiated the channel occupancy and/or DL signals/channels (PDSCH, PDCCH, reference signals) meant for the UE that initiated the channel occupancy.

1. The ED threshold that the UE applies when initiating a channel occupancy to be shared with the gNB is configured by gNB (RRC signaling) a. if ED threshold that the UE applies when initiating a channel occupancy to be shared with the gNB is not configured, the transmission of the gNB in UE initiated COT may include only control/broadcast signals/channels transmissions of up to 2/4/8 OFDM symbols in duration for 15/30/60 kHz SCS b. When absence of Wi-Fi cannot be assumed based on e.g. regulation, the ED threshold that the gNB configures to the UE to apply when initiating the channel occupancy is determined based on the max gNB TX power

2. Cat. 2 LBT can be used (for gaps of 16us and 25us).

3. Cat. 1 LBT can be used under the following conditions. a. Gap duration <= 16us b. For the transmission of the gNB after the first switch between the UE and the gNB if the gNB transmission contains only control/broadcast signals/channels c. For the transmission of the gNB after the first switch between the UE and the gNB if the gNB transmission has a duration below X ms (X >= 0).

[0071] For a Cat2 LBT in a 16 us gap, energy measurement is done for a total of at least 5 us with at least 4 us of sensing falling within the 9 us slot immediately before the transmission. i. LBT is said to be successful if the measured energy is lower than the ED threshold [0072] Basically, the NR-U LBT procedures for channel access can be summarized as follows: i. Both gNB-initiated and UE-initiated COTs use category 4 LBT where the start of a new transmission burst always perform LBT with exponential backoff. Only with exception, when the DRS must be at most one ms in duration and is not multiplexed with unicast PDSCH. ii. 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 16 ps, otherwise category 2 LBT must be used and the gap cannot exceed 25 ps.

[0073] Both the gNB and UE may LBT before performing a transmission on a cell configured with shared spectrum channel access. When LBT is applied, the transmitter listens to/senses the channel to determine whether the channel is free or busy and performs transmission only if the channel is sensed free.

[0074] When the UE detects consistent uplink LBT failures, it may take actions, e.g., as specified in TS 38.321. The detection is per BWP and based on all uplink transmissions within this BWP. When consistent uplink LBT failures are detected on a serving cell, the UE does the corresponding actions, e.g., as specified in TS38.321. For cases when sidelink is operated on a cell configured with shared spectrum, the corresponding UE actions upon detection of LBT failures for sidelink transmission need to be defined.

[0075] If UE would detect/declare consistent LBT failure per SL BWP and based on all SL transmissions within this BWP - as specified for the Uu interface (NR-U) - it may happen that consistent LBT failure is triggered even though the conge stion/LBT issue occurs only for a specific resource pool or sidelink connection/destination. Since a SL UE may be in communication with multiple different SL UEs at different locations, the channel conditions could be very different among the different sidelink connections.

[0076] The disclosure presents methods to allow for an efficient detection and recovery of consistent LBT failure for sidelink transmission on a cell configured with a shared spectrum.

[0077] In the various embodiments, as used herein, an antenna port is defined such that the channel over which a symbol on the antenna port is conveyed can be inferred from the channel over which another symbol on the same antenna port is conveyed. One or more antenna ports are used for UL transmissions.

[0078] Two antenna ports are said to be quasi co-located (“QCL”) if the large-scale properties of the channel over which a symbol on one antenna port is conveyed can be inferred from the channel over which a symbol on the other antenna port is conveyed. The large-scale properties include one or more of delay spread, Doppler spread, Doppler shift, average gain, average delay, and spatial Rx parameters. Two antenna ports may be quasi-located with respect to a subset of the large-scale properties. Spatial Rx parameters may include one or more of: angle of arrival (“AoA”,) Dominant AoA, average AoA, angular spread, Power Angular Spectrum (“PAS”) of AoA, average angle of departure (“AoD”), PAS of AoD, transmit/receive channel correlation, transmit/receive beamforming, spatial channel correlation, and/or the like.

[0079] An “antenna port,” as used herein, according to an embodiment, may be a logical port that may correspond to a beam (resulting from beamforming) or may correspond to a physical antenna on a device. In some embodiments, a physical antenna may map directly to a single antenna port, in which an antenna port corresponds to an actual physical antenna. Alternately, a set or subset of physical antennas, or antenna set or antenna array or antenna sub-array, may be mapped to one or more antenna ports after applying complex weights, a cyclic delay, or both to the signal on each physical antenna. The physical antenna set may have antennas from a single module or panel or from multiple modules or panels. The weights may be fixed as in an antenna virtualization scheme, such as cyclic delay diversity (“CDD”). The procedure used to derive antenna ports from physical antennas may be specific to a device implementation and transparent to other devices.

[0080] Throughout the different embodiments of the disclosure the term quasi co-located is to be understood mainly in the terms of transmit/receive beamforming respectively spatial channel correlation but should not be limited thereto.

[0081] According to one embodiment, consistent LBT failure is declared and/or detected per resource pool. In one implementation of this embodiment, the UE detects/declares a consistent LBT failure per Tx resource pool. According to one implementation of the embodiment, the UE declares consistent LBT failure for an Tx resource pool if a predefined number of LBT failures has been exceeded, satisfied, or met for a sidelink transmission within the resource pool, e.g., LBT_counter exceeds, satisfies, or meets a predefined threshold. In one embodiment, the LBT_counter is initialized to zero and incremented for every LBT failure indication received from PHY for a sidelink transmission (e.g., an attempt).

[0082] According to a further aspect of the embodiment, a Tx UE may autonomously deactivate a resource pool for cases where a predefined maximum number of LBT failures has been exceeded, satisfied, or met for a resource pool, and may switch to a different resource pool. Lor example, a UE may switch to a resource pool that uses a different LBT sub-band compared to the resource pool for which consistent LBT failures were detected/declared. If consistent LBT failure has been declared for all sidelink transmission resource pools within a SL BWP or a SL serving cell, in one embodiment, the Tx UE indicates consistent LBT failure to an upper layer(s). In one exemplary implementation of this embodiment, the Tx UE may switch the SL TX carrier/serving cell if the UE is configured with multiple SL cells/carriers.

[0083] According to one implementation of this embodiment, the Tx UE informs the gNB, e.g., for resource allocation mode 1, when it has detected/declared a consistent LBT failure for a resource pool. Such information may be provided by means of a MAC CE, where the MAC CE, e.g., also referred to as a Sidelink LBT failure MAC CE, may report consistent si de link LBT failure on one or more resource pool(s). In one specific implementation, the MAC CE indicates the indices of the resource pool(s) for which a consistent LBT failure was detected/declared. According to another implementation of the embodiment, the sidelink LBT failure MAC CE is identified by a MAC sub-header with a predefined logical channel identifier (“LCID”) and consists of a bitmap, where each entry of the bitmap refers to a resource pool. In one example if there is a resource pool configured for the Tx UE or MAC entity with ResourcePoolIndex i and if consistent LBT failure has been triggered/detected/declared and not cancelled for this resource pool, the field is set to 1, otherwise the field is set to 0.

[0084] According to one embodiment, the UE measures or counts LBT failures per destination ID. According to one implementation the UE or MAC layer of a sidelink UE counts LBT failures separately for each destination or connection it is in communication with. In one specific implementation, the UE maintains a LBT failure counter per sidelink destination respectively, per (Source Layer-2 ID, Destination Layer-2 ID) pair or alternatively per sidelink logical channel/radio bearer. In Rel-16, in one embodiment, consistent LBT failure is detected per UL BWP by counting LBT failure indications, for UL transmissions, from the lower layers to the MAC entity.

[0085] In one embodiment, RRC configures an LBT counter and a timer (e.g., Ibt- FailureDetectionTimer). The LBT counter, in one embodiment, is initialized to zero and incremented for every LBT failure indication from PHY. The timer may be restarted every time the LBT counter is incremented. When the timer expires, in one embodiment, the LBT counter is reset to 0. If the LBT counter reaches a preconfigured threshold (e.g., Ibt- FailurelnstanceMaxCount), consistent LBT failure is detected. According to this embodiment, a UE maintains the LBT counter and the LBT timer (e.g., Ibt-FailureDetectionTimer) per destination. In one implementation the LBT failure counter/timers are maintained per Rx UE that the Tx UE is in communication with. It should be noted that multiple destinations/SL LCHs/SL connections may belong to the same (Rx) UE.

[0086] In one embodiment, a motivation to perform the LBT failure detection and recovery procedure per destination pair of Tx UE/Rx UE is that different Rx UEs may be at different locations; hence, the channel/LBT situation may be significantly different among different Rx UEs that the Tx UE is in communication with. In particular for cases when a directional/spatial LBT is performed, e.g., for the NR operation in higher frequency bands up to 71 GHz, in contrast to an omni-directional LBT, which is the assumption for Rel-16, it is beneficial to maintain LBT statistics per destination/pair of (Source Layer-2 ID, Destination Layer-2 ID) respectively per pair of Tx UE and Rx UE and also to perform the LBT failure detection and recovery procedure per destination/pair of (Source Layer-2 ID, Destination Layer-2 ID). PHY indicates the LBT failure for a sidelink transmission (SL TB) on physical sidelink shared channel (“PSSCH”) or sidelink control information (“SCI”) on physical sidelink control channel (“PSCCH”) and MAC layer increments the LBT counter for the corresponding destination (Source Layer-2 ID, Destination Layer-2 ID) pair.

[0087] According to one implementation of this embodiment, the UE (e.g., Tx UE) deactivates sidelink transmissions to a specific destination or sidelink transmission for a specific (Source Layer-2 ID, Destination Layer-2 ID) pair for cases where the LBT counter has reached or exceeded a predefined threshold for that destination/pair of source Layer 2 ID and destination Layer 2 ID. In one implementation, the Tx UE doesn’t consider the SL LCHs associated with that destination for future LCP procedures/SL transmissions. In one specific implementation, SL LCHs associated with a destination for which the LBT counter reached, satisfied, or exceeded a predefined threshold are considered as suspended, e.g., SL LCHs are not considered for the destination selection and LCP procedure.

[0088] According to another implementation of this embodiment, the UE counts and/or reports LBT failure per group of destinations/pair of source destinations that have the same QCL relationship. The failure counter, in such an embodiment, is incremented per destination group when a SL transmission belonging to the same QCL group fails due to LBT failure.

[0089] According to another implementation, MAC layer indicates an LBT problem for a destination to higher layers for cases when the LBT counter reaches a predefined threshold forthat destination/(Source Layer-2 ID, Destination Layer-2 ID) pair.

[0090] According to one embodiment, the UE deactivates SL transmissions to a destination such as a Rx UE, e.g., destination Layer-2 ID, for which a consistent LBT failure was detected/declared. According to one implementation of the embodiment, the UE suspends the SL LCHs that are associated with a destination, e.g., destination Layer-2 ID, for which consistent LBT failure is detected/declared. In one example, the UE disables SL transmission to a destination for which consistent LBT failure is detected/declared for a predefined time period. In one embodiment, the UE starts a timer upon detecting/declaring a consistent LBT failure for a destination and, while the timer is running, the UE doesn’t perform SL transmission to the destination. In response to the expiry of the timer, in one embodiment, the UE resumes the SL LCHs associated with the destination and reactivate/enable SL transmissions to the destination.

[0091] According to one embodiment, the UE declares RLF for a sidelink destination/connection in response to a consistent LBT failure being detected for a sidelink connection/destination. It should be noted that in the legacy specifications, PC5-RRC also supports the detection of SL RLFs over the unicast NR SL communications. This is important to determine whether or when to release a SL unicast connection, for example, due to the degradation of the link as UEs move away from each other. In the legacy specifications, the lower layers trigger the SL RLF declaration when the maximum number of retransmissions to a specific destination has been reached or based on a number of received HARQ NACKs. According to this embodiment, a new trigger condition for declaring SL RLF is introduced, e.g., the UE triggers/declares SL RLF for a (unicast) connection in case consistent LBT failure has been detected for that destination/connection. Upon the declaration, the UE may release the PC5-RRC connection immediately and discards any associated SL UE context.

[0092] According to one embodiment, the UE autonomously deactivates a resource pool upon detecting/declaring consistent LBT failure for a resource pool. In one implementation, the UE deactivates a transmission resource pool for which consistent LBT failure is detected. In one example, there is a mapping that is defined/configured between a resource pool and LBT sub- band(s). Upon detecting consistent LBT failure for a resource pool, UE disables the resource pool for transmissions and switches to another resource pool (e.g., Tx resource pool) that has different associated LBT sub-band(s).

[0093] According to one implementation of the embodiment, the Tx UE stops sensing for the corresponding part of the Rx resource pool. In one example, in response to switching to another (configured) resource pool, the UE informs the gNB about the deactivated resource pool and switching to another resource pool. According to a further implementation of this embodiment, the Tx UE informs the corresponding Rx UE destination(s) about the resource pool switching. Such information may be transmitted via a PC5-RRC message for unicast connections or via a new MAC control signaling.

[0094] According to one implementation of the embodiment, the UE switches the Tx carrier for sidelink transmissions upon having detected/declared consistent LBT failure for all the Resource Pools/BWP(s) within the current Tx carrier.

[0095] According to one embodiment, the network configures whether the LBT failure detection procedure should be performed for a resource pool and/or a SL BWP.

[0096] According to one embodiment, the UE provides LBT information for a resource pool to the gNB, which considers the LBT information for future resource allocation/scheduling. In one example, the LBT information comprises at least one of the following: i. LBT statistics such as e.g., LBT failure to LBT success ratio for SL transmissions in a resource pool; ii. Current LBT counter/timer values; iii. Event that LBT counter reaches/exceeds a predefined threshold; and/or iv. LBT statistics per destination ID/source of Source Layer 2 ID and Destination Layer 2 ID, e.g., LBT failure rate per destination/source-destination pair. [0097] According to one implementation of this embodiment, the LBT information for a resource pool is reported within a MAC CE from a SL UE to the gNB. In another implementation, the UE uses RRC signaling, e.g., LBT information is provided within the SL assistance information, for reporting LBT information to the gNB. The reporting could be either event- triggered, e.g., LBT information is provided for cases when a certain predefined event/criteria is occurred/fulfilled, or periodically reported, e.g., periodicity may be (pre)configured.

[0098] According to another implementation of this example, the gNB may explicitly request LBT information from a SL UE. In one example, such explicit LBT request is signaled within a DCI. A new field, e.g., a one-bit field, may indicate the request to report LBT information to a SL UE. According to one implementation, the gNB may indicate which resource pools to provide LBT information, e.g., the request may contain the IDs/indices of the resource pools for which the SL UE shall provide LBT information. According to one implementation of the embodiment, the network configures whether LBT information reporting to the gNB should be applied by a SL (Tx) UE.

[0099] Eigure 3 depicts a user equipment apparatus 300 that may be used for listen before talk failure procedures for sidelink connections, according to embodiments of the disclosure. In various embodiments, the user equipment apparatus 300 is used to implement one or more of the solutions described above. The user equipment apparatus 300 may be one embodiment of the remote unit 105 and/or the UE 205, described above. Furthermore, the user equipment apparatus 300 may include a processor 305, a memory 310, an input device 315, an output device 320, and a transceiver 325.

[0100] In some embodiments, the input device 315 and the output device 320 are combined into a single device, such as a touchscreen. In certain embodiments, the user equipment apparatus 300 may not include any input device 315 and/or output device 320. In various embodiments, the user equipment apparatus 300 may include one or more of: the processor 305, the memory 310, and the transceiver 325, and may not include the input device 315 and/or the output device 320.

[0101] As depicted, the transceiver 325 includes at least one transmitter 330 and at least one receiver 335. In some embodiments, the transceiver 325 communicates with one or more cells (or wireless coverage areas) supported by one or more base units 121. In various embodiments, the transceiver 325 is operable on unlicensed spectrum. Moreover, the transceiver 325 may include multiple UE panel supporting one or more beams. Additionally, the transceiver 325 may support at least one network interface 340 and/or application interface 345. The application interface(s) 345 may support one or more APIs. The network interface(s) 340 may support 3GPP reference points, such as Uu, Nl, PC5, etc. Other network interfaces 340 may be supported, as understood by one of ordinary skill in the art.

[0102] The processor 305, in one embodiment, may include any known controller capable of executing computer-readable instructions and/or capable of performing logical operations. For example, the processor 305 may be a microcontroller, a microprocessor, a central processing unit (“CPU”), a graphics processing unit (“GPU”), an auxiliary processing unit, a field programmable gate array (“FPGA”), or similar programmable controller. In some embodiments, the processor 305 executes instructions stored in the memory 310 to perform the methods and routines described herein. The processor 305 is communicatively coupled to the memory 310, the input device 315, the output device 320, and the transceiver 325. In certain embodiments, the processor 305 may include an application processor (also known as “main processor”) which manages applicationdomain and operating system (“OS”) functions and a baseband processor (also known as “baseband radio processor”) which manages radio functions.

[0103] In various embodiments, the processor 305 and/or transceiver 325 controls the user equipment apparatus 300 to implement the above-described UE behaviors. In one embodiment, the transceiver 325 performs EBT for a sidelink transmission, the sidelink transmission addressed to a first destination identity. In one embodiment, the processor 305 detects an EBT failure for a first resource pool associated with the sidelink transmission, deactivates the first resource pool for sidelink transmissions in response to determining that the detected LBT failure satisfies a predefined failure threshold for the resource pool, and switches to a second resource pool for sidelink transmissions.

[0104] In one embodiment, the processor 305 notifies a network entity the UE is connected with of the switch to the second resource pool.

[0105] In one embodiment, the processor 305 notifies the first destination identity of the switch to the second resource pool.

[0106] In one embodiment, the notification is transmitted using a sidelink LBT failure MAC CE.

[0107] In one embodiment, the MAC CE comprises an index for the first resource pool associated with the detected LBT failure.

[0108] In one embodiment, the MAC CE is identified by a MAC sub-header with a predefined LCID, the MAC CE comprising a bitmap where each entry of the bitmap refers to a resource pool. [0109] In one embodiment, the processor 305 increments an LBT failure counter for the resource pool in response to detecting the LBT failure, the LBT resource counter used to determine whether the LBT failure satisfies the predetermined failure threshold.

[0110] In one embodiment, the processor 305 initializes the LBT failure counter with a zero value and increment the LBT failure counter for every LBT failure indication received from a physical layer for a sidelink transmission.

[0111] In one embodiment, the second resource pool has a different LBT sub-band than the first resource pool.

[0112] In one embodiment, the processor 305 indicates to an upper network layer consistent LBT failure in response to the detected LBT failure satisfying the predefined failure threshold.

[0113] In one embodiment, the processor 305 switches one or more of the sidelink carrier and serving cell in response to the detected LBT failure satisfying the predefined failure threshold.

[0114] In one embodiment, the processor 305 triggers RLF for the sidelink transmission to the first destination identity in response to the detected LBT failure satisfying the predefined failure threshold.

[0115] In one embodiment, the processor 305 receives an indication from a network to perform LBT failure detection for the first resource pool, a sidelink bandwidth part, or some combination thereof.

[0116] In one embodiment, the processor 305 performs LBT for a sidelink transmission, the sidelink transmission addressed to a first destination identity, detects an LBT failure associated with the sidelink transmission, increments a counter in response to the detected LBT failure, the counter associated with the first destination identity, and deactivates sidelink transmissions to the first destination identity in response to the counter satisfying a predefined threshold.

[0117] In one embodiment, the processor 305 suspends a sidelink logical channel associated with the first destination identity in response to the counter satisfying the predefined threshold.

[0118] In one embodiment, the processor 305 starts a timer in response to the counter satisfying the predefined threshold.

[0119] In one embodiment, the processor 305 resumes the suspended sidelink logical channel associated with the first destination identity in response to expiry of the timer.

[0120] In one embodiment, the processor 305 ignores the first destination identity for destination selection during a sidelink logical channel prioritization procedure in response to the counter satisfying the predefined threshold. [0121] The memory 310, in one embodiment, is a computer readable storage medium. In some embodiments, the memory 310 includes volatile computer storage media. For example, the memory 310 may include a RAM, including dynamic RAM (“DRAM”), synchronous dynamic RAM (“SDRAM”), and/or static RAM (“SRAM”). In some embodiments, the memory 310 includes non-volatile computer storage media. For example, the memory 310 may include a hard disk drive, a flash memory, or any other suitable non-volatile computer storage device. In some embodiments, the memory 310 includes both volatile and non-volatile computer storage media.

[0122] In some embodiments, the memory 310 stores data related to listen before talk failure procedures for sidelink connections. For example, the memory 310 may store various parameters, panel/beam configurations, resource assignments, policies, and the like as described above. In certain embodiments, the memory 310 also stores program code and related data, such as an operating system or other controller algorithms operating on the user equipment apparatus 300.

[0123] The input device 315, in one embodiment, may include any known computer input device including a touch panel, a button, a keyboard, a stylus, a microphone, or the like. In some embodiments, the input device 315 may be integrated with the output device 320, for example, as a touchscreen or similar touch -sensitive display. In some embodiments, the input device 315 includes a touchscreen such that text may be input using a virtual keyboard displayed on the touchscreen and/or by handwriting on the touchscreen. In some embodiments, the input device 315 includes two or more different devices, such as a keyboard and a touch panel.

[0124] The output device 320, in one embodiment, is designed to output visual, audible, and/or haptic signals. In some embodiments, the output device 320 includes an electronically controllable display or display device capable of outputting visual data to a user. For example, the output device 320 may include, but is not limited to, an LCD display, an LED display, an OLED display, a projector, or similar display device capable of outputting images, text, or the like to a user. As another, non-limiting, example, the output device 320 may include a wearable display separate from, but communicatively coupled to, the rest of the user equipment apparatus 300, such as a smart watch, smart glasses, a heads-up display, or the like. Further, the output device 320 may be a component of a smart phone, a personal digital assistant, a television, a table computer, a notebook (laptop) computer, a personal computer, a vehicle dashboard, or the like.

[0125] In certain embodiments, the output device 320 includes one or more speakers for producing sound. For example, the output device 320 may produce an audible alert or notification (e.g., a beep or chime). In some embodiments, the output device 320 includes one or more haptic devices for producing vibrations, motion, or other haptic feedback. In some embodiments, all, or portions of the output device 320 may be integrated with the input device 315. For example, the input device 315 and output device 320 may form atouchscreen or similar touch-sensitive display. In other embodiments, the output device 320 may be located near the input device 315.

[0126] The transceiver 325 communicates with one or more network functions of a mobile communication network via one or more access networks. The transceiver 325 operates under the control of the processor 305 to transmit messages, data, and other signals and also to receive messages, data, and other signals. For example, the processor 305 may selectively activate the transceiver 325 (or portions thereof) at particular times in order to send and receive messages.

[0127] The transceiver 325 includes at least one transmitter 330 and at least one receiver 335. One or more transmitters 330 may be used to provide UL communication signals to a base unit 121, such as the UL transmissions described herein. Similarly, one or more receivers 335 may be used to receive DL communication signals from the base unit 121, as described herein. Although only one transmitter 330 and one receiver 335 are illustrated, the user equipment apparatus 300 may have any suitable number of transmitters 330 and receivers 335. Further, the transmitter(s) 330 and the receiver(s) 335 may be any suitable type of transmitters and receivers. In one embodiment, the transceiver 325 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.

[0128] In certain embodiments, the first transmitter/receiver pair used to communicate with a mobile communication network over licensed radio spectrum and the second transmitter/receiver pair used to communicate with a mobile communication network over unlicensed radio spectrum may be combined into a single transceiver unit, for example a single chip performing functions for use with both licensed and unlicensed radio spectrum. In some embodiments, the first transmitter/receiver pair and the second transmitter/receiver pair may share one or more hardware components. For example, certain transceivers 325, transmitters 330, and receivers 335 may be implemented as physically separate components that access a shared hardware resource and/or software resource, such as for example, the network interface 340.

[0129] In various embodiments, one or more transmitters 330 and/or one or more receivers 335 may be implemented and/or integrated into a single hardware component, such as a multitransceiver chip, a system-on -a-chip, an ASIC, or other type of hardware component. In certain embodiments, one or more transmitters 330 and/or one or more receivers 335 may be implemented and/or integrated into a multi -chip module. In some embodiments, other components such as the network interface 340 or other hardware components/circuits may be integrated with any number of transmiters 330 and/or receivers 335 into a single chip. In such embodiment, the transmiters 330 and receivers 335 may be logically configured as a transceiver 325 that uses one more common control signals or as modular transmiters 330 and receivers 335 implemented in the same hardware chip or in a multi -chip module.

[0130] Figure 4 depicts a network apparatus 400 that may be used for listen before talk failure procedures for sidelink connections, according to embodiments of the disclosure. In one embodiment, network apparatus 400 may be one implementation of a RAN node, such as the base unit 121, the RAN node 210, or gNB, described above. Furthermore, the base network apparatus 400 may include a processor 405, a memory 410, an input device 415, an output device 420, and a transceiver 425.

[0131] In some embodiments, the input device 415 and the output device 420 are combined into a single device, such as a touchscreen. In certain embodiments, the network apparatus 400 may not include any input device 415 and/or output device 420. In various embodiments, the network apparatus 400 may include one or more of: the processor 405, the memory 410, and the transceiver 425, and may not include the input device 415 and/or the output device 420.

[0132] As depicted, the transceiver 425 includes at least one transmiter 430 and at least one receiver 435. Here, the transceiver 425 communicates with one or more remote units 105. Additionally, the transceiver 425 may support at least one network interface 440 and/or application interface 445. The application interface(s) 445 may support one or more APIs. The network interface(s) 440 may support 3GPP reference points, such as Uu, Nl, N2 and N3. Other network interfaces 440 may be supported, as understood by one of ordinary skill in the art.

[0133] The processor 405, in one embodiment, may include any known controller capable of executing computer-readable instructions and/or capable of performing logical operations. For example, the processor 405 may be a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or similar programmable controller. In some embodiments, the processor 405 executes instructions stored in the memory 410 to perform the methods and routines described herein. The processor 405 is communicatively coupled to the memory 410, the input device 415, the output device 420, and the transceiver 425. In certain embodiments, the processor 805 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 function.

[0134] The memory 410, in one embodiment, is a computer readable storage medium. In some embodiments, the memory 410 includes volatile computer storage media. For example, the memory 410 may include a RAM, including DRAM, SDRAM, and/or SRAM. In some embodiments, the memory 410 includes non-volatile computer storage media. For example, the memory 410 may include a hard disk drive, a flash memory, or any other suitable non-volatile computer storage device. In some embodiments, the memory 410 includes both volatile and nonvolatile computer storage media.

[0135] In some embodiments, the memory 410 stores data related to listen before talk failure procedures for sidelink connections. For example, the memory 410 may store parameters, configurations, resource assignments, policies, and the like, as described above. In certain embodiments, the memory 410 also stores program code and related data, such as an operating system or other controller algorithms operating on the network apparatus 400.

[0136] The input device 415, in one embodiment, may include any known computer input device including a touch panel, a button, a keyboard, a stylus, a microphone, or the like. In some embodiments, the input device 415 may be integrated with the output device 420, for example, as a touchscreen or similar touch -sensitive display. In some embodiments, the input device 415 includes a touchscreen such that text may be input using a virtual keyboard displayed on the touchscreen and/or by handwriting on the touchscreen. In some embodiments, the input device 415 includes two or more different devices, such as a keyboard and a touch panel.

[0137] The output device 420, in one embodiment, is designed to output visual, audible, and/or haptic signals. In some embodiments, the output device 420 includes an electronically controllable display or display device capable of outputting visual data to a user. For example, the output device 420 may include, but is not limited to, an LCD display, an LED display, an OLED display, a projector, or similar display device capable of outputting images, text, or the like to a user. As another, non-limiting, example, the output device 420 may include a wearable display separate from, but communicatively coupled to, the rest of the network apparatus 400, such as a smart watch, smart glasses, a heads-up display, or the like. Further, the output device 420 may be a component of a smart phone, a personal digital assistant, a television, a table computer, a notebook (laptop) computer, a personal computer, a vehicle dashboard, or the like.

[0138] In certain embodiments, the output device 420 includes one or more speakers for producing sound. For example, the output device 420 may produce an audible alert or notification (e.g., a beep or chime). In some embodiments, the output device 420 includes one or more haptic devices for producing vibrations, motion, or other haptic feedback. In some embodiments, all, or portions of the output device 420 may be integrated with the input device 415. For example, the input device 415 and output device 420 may form atouchscreen or similar touch-sensitive display. In other embodiments, the output device 420 may be located near the input device 415. [0139] The transceiver 425 includes at least transmitter 430 and at least one receiver 435. One or more transmitters 430 may be used to communicate with the UE, as described herein. Similarly, one or more receivers 435 may be used to communicate with network functions in the NPN, PLMN and/or RAN, as described herein. Although only one transmitter 430 and one receiver 435 are illustrated, the network apparatus 400 may have any suitable number of transmitters 430 and receivers 435. Further, the transmitter(s) 430 and the receiver(s) 435 may be any suitable type of transmitters and receivers.

[0140] Figure 5 is a flowchart diagram of a method 500 for listen before talk failure procedures for sidelink connections. The method 500 may be performed by a UE as described herein, for example, the remote unit 105, the UE 205 and/or the user equipment apparatus 300. In some embodiments, the method 500 may be performed by a processor executing program code, for example, a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like.

[0141] The method 500, in one embodiment, includes performing 505 LBT for a sidelink transmission, the sidelink transmission addressed to a first destination identity. In one embodiment, the method 500 includes detecting an LBT failure for a first resource pool associated with the sidelink transmission. In one embodiment, the method 500 includes deactivating 515 the first resource pool for sidelink transmissions in response to determining that the detected LBT failure satisfies a predefined failure threshold for the resource pool. In one embodiment, the method 500 includes switching 520 to a second resource pool for sidelink transmissions. The method 500 ends.

[0142] Figure 6 is a flowchart diagram of a method 600 for listen before talk failure procedures for sidelink connections. The method 600 may be performed by a UE as described herein, for example, the remote unit 105, the UE 205 and/or the user equipment apparatus 300. In some embodiments, the method 600 may be performed by a processor executing program code, for example, a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like.

[0143] In one embodiment, the method 600 includes performing 605 LBT for a sidelink transmission, the sidelink transmission addressed to a first destination identity. In one embodiment, the method 600 includes detecting 610 an LBT failure associated with the sidelink transmission. In one embodiment, the method 600 includes incrementing 615 a counter in response to the detected LBT failure, the counter associated with the first destination identity. In one embodiment, the method 600 includes deactivating 620 sidelink transmissions to the first destination identity in response to the counter satisfying a predefined threshold. The method 600 ends.

[0144] A first apparatus is disclosed for listen before talk failure procedures for sidelink connections. The first apparatus may be embodied as a UE as described herein, for example, the remote unit 105, the UE 205 and/or the user equipment apparatus 300. In some embodiments, the first apparatus may include a processor executing program code, for example, a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like.

[0145] In one embodiment, a first apparatus includes a memory and a processor coupled to the memory. In one embodiment, the processor is configured to cause the apparatus to perform LBT for a sidelink transmission, the sidelink transmission addressed to a first destination identity. In one embodiment, the processor is configured to cause the apparatus to detect an LBT failure for a first resource pool associated with the sidelink transmission, deactivate the first resource pool for sidelink transmissions in response to determining that the detected LBT failure satisfies a predefined failure threshold for the resource pool, and switch to a second resource pool for sidelink transmissions.

[0146] In one embodiment, the processor is configured to cause the apparatus to notify a network entity the UE is connected with of the switch to the second resource pool.

[0147] In one embodiment, the processor is configured to cause the apparatus to notify the first destination identity of the switch to the second resource pool.

[0148] In one embodiment, the notification is transmitted using a sidelink LBT failure MAC CE.

[0149] In one embodiment, the MAC CE comprises an index for the first resource pool associated with the detected LBT failure.

[0150] In one embodiment, the MAC CE is identified by a MAC sub-header with a predefined LCID, the MAC CE comprising a bitmap where each entry of the bitmap refers to a resource pool.

[0151] In one embodiment, the processor is configured to cause the apparatus to increment an LBT failure counter for the resource pool in response to detecting the LBT failure, the LBT resource counter used to determine whether the LBT failure satisfies the predetermined failure threshold.

[0152] In one embodiment, the processor is configured to cause the apparatus to initialize the LBT failure counter with a zero value and increment the LBT failure counter for every LBT failure indication received from a physical layer for a sidelink transmission. [0153] In one embodiment, the second resource pool has a different LBT sub-band than the first resource pool.

[0154] In one embodiment, the processor is configured to cause the apparatus to indicate to an upper network layer consistent LBT failure in response to the detected LBT failure satisfying the predefined failure threshold.

[0155] In one embodiment, the processor is configured to cause the apparatus to switch one or more of the sidelink carrier and serving cell in response to the detected LBT failure satisfying the predefined failure threshold.

[0156] In one embodiment, the processor is configured to cause the apparatus to trigger RLF for the sidelink transmission to the first destination identity in response to the detected LBT failure satisfying the predefined failure threshold.

[0157] In one embodiment, the processor is configured to cause the apparatus to receive an indication from a network to perform LBT failure detection for the first resource pool, a sidelink bandwidth part, or some combination thereof.

[0158] A first method is disclosed for listen before talk failure procedures for sidelink connections. The first method may be performed by a UE as described herein, for example, the remote unit 105, the UE 205 and/or the user equipment apparatus 300. In some embodiments, the first method may be performed by a processor executing program code, for example, a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like.

[0159] In one embodiment, a first method includes performing LBT for a sidelink transmission, the sidelink transmission addressed to a first destination identity. In one embodiment, the first method includes detecting an LBT failure for a first resource pool associated with the sidelink transmission, deactivating the first resource pool for sidelink transmissions in response to determining that the detected LBT failure satisfies a predefined failure threshold for the resource pool, and switching to a second resource pool for sidelink transmissions.

[0160] In one embodiment, the first method includes notifying, via the transceiver, a network entity the UE is connected with of the switch to the second resource pool.

[0161] In one embodiment, the first method includes notifying, via the transceiver, the first destination identity of the switch to the second resource pool.

[0162] In one embodiment, the notification is transmitted using a sidelink LBT failure MAC CE.

[0163] In one embodiment, the MAC CE comprises an index for the first resource pool associated with the detected LBT failure. [0164] In one embodiment, the MAC CE is identified by a MAC sub-header with a predefined LCID, the MAC CE comprising a bitmap where each entry of the bitmap refers to a resource pool.

[0165] In one embodiment, the first method includes incrementing an LBT failure counter for the resource pool in response to detecting the LBT failure, the LBT resource counter used to determine whether the LBT failure satisfies the predetermined failure threshold.

[0166] In one embodiment, the first method includes initializing the LBT failure counter with a zero value and increment the LBT failure counter for every LBT failure indication received from a physical layer for a sidelink transmission.

[0167] In one embodiment, the second resource pool has a different LBT sub-band than the first resource pool.

[0168] In one embodiment, the first method includes indicating to an upper network layer consistent LBT failure in response to the detected LBT failure satisfying the predefined failure threshold.

[0169] In one embodiment, the first method includes switching one or more of the sidelink carrier and serving cell in response to the detected LBT failure satisfying the predefined failure threshold.

[0170] In one embodiment, the first method triggers RLE for the sidelink transmission to the first destination identity in response to the detected LBT failure satisfying the predefined failure threshold.

[0171] In one embodiment, the first method includes receiving an indication from a network to perform LBT failure detection for the first resource pool, a sidelink bandwidth part, or some combination thereof.

[0172] A second apparatus is disclosed for listen before talk failure procedures for sidelink connections. The second apparatus may be embodied as a UE as described herein, for example, the remote unit 105, the UE 205 and/or the user equipment apparatus 300. In some embodiments, the second apparatus includes a processor executing program code, for example, a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like.

[0173] In one embodiment, the second apparatus includes a memory and a processor coupled to the memory. In one embodiment, the processor is configured to cause the apparatus to perform LBT for a sidelink transmission, the sidelink transmission addressed to a first destination identity, detect an LBT failure associated with the sidelink transmission, increment a counter in response to the detected LBT failure, the counter associated with the first destination identity, and deactivate sidelink transmissions to the first destination identity in response to the counter satisfying a predefined threshold.

[0174] In one embodiment, the processor is configured to cause the apparatus to suspend a sidelink logical channel associated with the first destination identity in response to the counter satisfying the predefined threshold.

[0175] In one embodiment, the processor is configured to cause the apparatus to start a timer in response to the counter satisfying the predefined threshold.

[0176] In one embodiment, the processor is configured to cause the apparatus to resume the suspended sidelink logical channel associated with the first destination identity in response to expiry of the timer.

[0177] In one embodiment, the processor is configured to cause the apparatus to ignore the first destination identity for destination selection during a sidelink logical channel prioritization procedure in response to the counter satisfying the predefined threshold.

[0178] A second method is disclosed for listen before talk failure procedures for sidelink connections. The second method may be performed by a UE as described herein, for example, the remote unit 105, the UE 205 and/or the user equipment apparatus 300. In some embodiments, the second method may be performed by a processor executing program code, for example, a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like.

[0179] In one embodiment, the second method includes performing LBT for a sidelink transmission, the sidelink transmission addressed to a first destination identity. In one embodiment, the second method includes detecting an LBT failure associated with the sidelink transmission, incrementing a counter in response to the detected LBT failure, the counter associated with the first destination identity, and deactivating sidelink transmissions to the first destination identity in response to the counter satisfying a predefined threshold.

[0180] In one embodiment, the second method includes suspending a side link logical channel associated with the first destination identity in response to the counter satisfying the predefined threshold.

[0181] In one embodiment, the second method includes starting a timer in response to the counter satisfying the predefined threshold.

[0182] In one embodiment, the second method includes resuming the suspended sidelink logical channel associated with the first destination identity in response to expiry of the timer. [0183] In one embodiment, the second method includes ignoring the first destination identity for destination selection during a sidelink logical channel prioritization procedure in response to the counter satisfying the predefined threshold.

[0184] Embodiments may be practiced in other specific forms. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.