Determination of the sidelink connection timer for establishing communication via sidelink relays.

Abstract

Apparatus, methods, and systems for configuring sidelink connection timers are disclosed. One method (1300) includes receiving (1305) a set of connection timers from a first system information block transmission of a serving node and receiving (1310) a first set of sidelink connection timers from an additional system information block of the serving node. The method (1300) includes determining (1315) a second set of sidelink connection timers for establishment of communication with a network node using an UE-to-Network ("U2N") sidelink relay UE, where a respective value of each timer of the second set of sidelink connection timers is determined based at least in part on the first set of sidelink connection timers. The method (1300) includes using (1320) the respective connection timers to manage establishment of communication with the network node via the U2N sidelink relay UE.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims priority to U.S. Provisional Patent Application No. 63 / 287,251, filed on January 21, 2023, entitled "SIGNALING CONNECTION ESTABLISHMENT TIMERS TO A SIDELINK REMOTE UE" by Prateek Basu Mallick, Karthikeyan Ganesan, Joachim Lohr, and Ravi Kuchibhotla, which is hereby incorporated by reference herein.

[0002] The subject matter disclosed herein generally relates to wireless communications, and more particularly, for example, to configuring connection establishment timers for sidelink communication for establishing communication between a remote user equipment ("UE") and a network node using, for example, UE - to - Network ("U2N") sidelink relay.

Background Art

[0003] In sidelink communication, a UE can communicate directly with another UE without relaying its messages through a wireless network. In the Third Generation Partnership Project ("3GPP" (trademark, same hereinafter)), sidelink communication may be used to extend the service area of a RAN by relaying signaling between a UE outside coverage and a serving network node (e.g., a radio access network ("RAN") node) to a UE within coverage (i.e., via sidelink communication).

Prior Art Documents

Non - Patent Documents

[0004]

Non - Patent Document 1

[0005] Disclosed is a procedure relating to configuring a connection establishment timer for sidelink communication, also referred to herein as a “sidelink connection timer.” The procedure may be implemented by an apparatus, system, method, or computer program product.

[0006] One method in the UE includes the steps of receiving a set of connection timers from a first system information block transmission of the serving node and receiving a first set of sidelink connection timers from an additional system information block of the serving node. The method includes determining a second set of sidelink connection timers for establishing communication with a network node using the U2N sidelink relay UE, wherein the respective value of each timer in the second set of sidelink connection timers is determined at least in part on the first set of sidelink connection timers. The method includes using the respective connection timers to manage the establishment of communication with a network node via the U2N sidelink relay UE.

[0007] A more detailed description of the embodiments briefly described above is made by reference to specific embodiments illustrated in the accompanying drawings. Understanding that these drawings only illustrate a few embodiments and should therefore not be considered limitations of scope, the embodiments are described and explained more specifically and in detail using the accompanying drawings. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic block diagram showing one embodiment of a wireless communication system for configuring a sidelink connection timer. [Figure 2] This is a block diagram showing one embodiment of the protocol stack for New Radio ("NR"). [Figure 3] This figure shows one embodiment of the procedure for establishing a connection between an out-of-coverage UE and a serving network node via a U2N sidelink relay UE. [Figure 4] This figure shows one embodiment of the procedure for re-establishing connectivity between an out-of-coverage UE and a serving network node via a U2N sidelink relay UE. [Figure 5] This figure shows one embodiment of the procedure for resuming connectivity between an out-of-coverage UE and a serving network node via a U2N sidelink relay UE. [Figure 6] This figure shows one embodiment of a connection resumption procedure involving the release or interruption of the network between an out-of-coverage UE and a serving network node via a U2N sidelink relay UE. [Figure 7] This figure shows one embodiment of an information element ("IE") that includes a UE timer and a set of constants. [Figure 8] This figure shows one embodiment of the IE, which includes a set of sidelink-specific UE timers and constants. [Figure 8] This figure shows one embodiment of a sixth interlacing scheme for sidelink operation. [Figure 9A] This figure shows one embodiment of System Information Block #1 ("SIB1"), which includes a set of UE timers and constants, as well as an additional offset time for connection procedures via side link relays. [Figure 9B] This is a continuation of the diagram of SIB1 shown in Figure 9A. [Figure 10] This is a block diagram showing one embodiment of a side link relay arrangement and associated connection timer. [Figure 11]This is a block diagram showing one embodiment of a user device that may be used to configure a sidelink connection timer. [Figure 12] This is a block diagram showing one embodiment of a network device that may be used to configure a sidelink connection timer. [Figure 13] This flowchart shows one embodiment of a first method for configuring a sidelink connection timer. [Modes for carrying out the invention]

[0009] As will be understood by those skilled in the art, embodiments of the models may be embodied as systems, apparatus, methods, or program products. Accordingly, embodiments may take the form of all hardware embodiments, all software embodiments (including firmware, resident software, microcode, etc.), or embodiments that combine software and hardware embodiments.

[0010] For example, the disclosed embodiments may be implemented as hardware circuits including custom very large-scale integrated circuits ("VLSI") or off-the-shelf semiconductors, transistors, or other discrete components such as gate arrays, logic chips, etc. The disclosed embodiments may also be implemented in programmable hardware devices such as field-programmable gate arrays, programmable array logic, or programmable logic devices. As another example, the disclosed embodiments may include one or more physical or logical blocks of executable code, which may be organized as objects, procedures, or functions, for example.

[0011] Furthermore, an embodiment may take the form of a program product embodied in one or more computer-readable storage devices storing a machine-readable code, a computer-readable code, and / or a program code hereinafter referred to as code. The storage device may be tangible, non-transitory, and / or non-transmissive. The storage device may not embody a signal. In certain embodiments, the storage device employs only signals for accessing the code.

[0012] Any combination of one or more computer-readable media may be utilized. The computer-readable media may be a computer-readable storage media. The computer-readable storage media 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, micro-mechanical, or semiconductor system, apparatus, or device, or any suitable combination thereof.

[0013] More specific examples (non-exhaustive list) of storage devices include, hereinafter, an electrical connection having one or more wirings, 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 disk read-only memory ("CD-ROM"), an optical storage device, a magnetic storage device, or any suitable combination thereof. In the context of this specification, a computer-readable storage media may be any tangible media that can include or store a program for use by or in connection with an instruction execution system, apparatus, or device.

[0014] The code for performing the operations of the embodiments may be in any number of lines and may be written in any combination of one or more programming languages, including object-oriented programming languages such as Python, Ruby, Java, Smalltalk, C++; conventional procedural programming languages such as the "C" programming language; and / or machine languages such as assembly language. The code may be executed entirely on the user's computer, partially on the user's computer as a stand-alone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the last scenario, the remote computer may be connected to the user's computer via any type of network, including a local area network ("LAN"), a wireless LAN ("WLAN"), or a wide area network ("WAN"), or the connection to an external computer may be made (e.g., via the Internet using an Internet service provider ("ISP")).

[0015] Furthermore, the features, structures, or characteristics described in the embodiments may be combined in any suitable way. In the following description, numerous specific details, such as examples of programming, software modules, user selections, network transactions, database queries, database structures, hardware modules, hardware circuits, hardware chips, etc., are provided to enable a complete understanding of the embodiments. However, those skilled in the art will recognize that the embodiments may be practiced without one or more of the specific details or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the embodiments.

[0016] Throughout this specification, any reference to “one embodiment,” “an embodiment,” or similar wording means that a particular feature, structure, or characteristic described in relation to an embodiment is included in at least one embodiment. Thus, throughout this specification, any occurrence of the phrase “in one embodiment,” “in an embodiment,” and similar wording may, but not necessarily, refer to the same embodiment and may mean “one or more, but not all, embodiments” unless otherwise specified. The terms “including,” “comprising,” “having,” and their variations mean “including, but not limited to,” unless otherwise specified. An enumerated list of items does not imply that any or all of the items are mutually exclusive unless otherwise specified. Also, the terms “a,” “an,” and “the” mean “one or more” unless otherwise specified.

[0017] As used herein, a list using the conjunction "and / or" includes any single item in the list or any combination of items in the list. For example, the list A, B, and / or C includes A only, B only, C only, 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 term "one or more of" includes any single item in the list or any combination of items in the list. For example, one or more of A, B, and C includes A only, B only, C only, 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 term "one of" includes just one of any single items in the list. For example, “one of A, B, and C” includes A only, B only, or C only, and excludes combinations of A, B, and C. When used herein, “at least one of A, B, and C” includes A only, B only, C only, 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. When used herein, “a member selected from the group consisting of A, B, and C” includes just one of A, B, or C, and excludes combinations of A, B, and C. When used herein, “a member selected from the group consisting of A, B, and C and combinations thereof” includes A only, B only, C only, 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.

[0018] Aspects of the embodiments are described below with reference to schematic flowcharts and / or schematic block diagrams of methods, apparatus, systems, and program products according to the embodiments. It will be understood that each block in the schematic flowcharts and / or schematic block diagrams, as well as combinations of blocks in the schematic flowcharts and / or schematic block diagrams, can be implemented by code. This code may be provided to a processor of a multipurpose computer, a dedicated computer, or other programmable data processing device to generate a machine such that instructions executed by the processor of the computer or other programmable data processing device produce means for performing the functions / actions defined in the flowcharts and / or block diagrams.

[0019] The code may be stored in a storage device that can instruct a computer, other programmable data processing device, or other device to function in a particular way so that the instructions stored in the storage device produce a product containing instructions that perform functions / actions defined in flowcharts and / or block diagrams.

[0020] The code may be loaded into a computer, other programmable device, or other device to perform a series of operational steps on the computer, other programmable device, or other device, so as to provide a process for the code to be executed by the computer to perform the functions / actions defined in the flowchart and / or block diagram.

[0021] The call-flow diagrams, flowcharts, and / or block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of devices, systems, methods, and program products in various embodiments. In this regard, each block in the flowcharts and / or block diagrams may represent a module, segment, or portion of code containing one or more executable instructions of code for implementing a defined logical function.

[0022] It should also be noted that in some alternative implementations, the functions shown in the blocks may be performed in a different order than that shown in the diagram. For example, two blocks shown consecutively may actually be executed substantially simultaneously, or blocks may be executed in reverse order depending on the function they relate to. Other steps and methods may be devised that are equivalent in function, logic, or effect to one or more blocks or parts of the diagram shown.

[0023] Various types of arrows and lines may be used in call flow diagrams, flowcharts, and / or block diagrams, but they are understood not to limit the scope of the corresponding embodiment. In fact, some arrows or other connectors may be used only to indicate the logical flow of the shown embodiment. For example, an arrow may indicate a waiting or monitoring period of an unspecified duration between enumerated steps of the shown embodiment. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in a block diagram and / or flowchart, may be implemented by a system based on dedicated hardware that performs a defined function or action, or by a combination of dedicated hardware and code.

[0024] The descriptions of elements in each figure may refer to elements in the procedure diagrams. Similar numbers refer to similar elements in all figures, including alternative embodiments of similar elements.

[0025] Configure a sidelink connection timer. In certain embodiments, the method may be performed using computer code embedded in a computer-readable medium. In certain embodiments, the device or system may include a computer-readable medium containing computer-readable code that, when executed by a processor, causes the device or system to perform at least a portion of the solutions described below.

[0026] To achieve coverage extension, remote UEs may need to select and reselect UE-to-UE network ("U2N") relays from time to time due to radio conditions and / or higher-layer criteria. Radio conditions may be configured (or pre-configured) so that when the radio quality of the current serving relay UE (e.g., a reference signal received power ("RSRP") measurement) falls below a certain threshold, the remote UE searches for a candidate relay that meets higher-layer criteria (if any) and exceeds a specific (pre-configured) threshold.

[0027] As a preliminary step, considering a wider range of applications and services, sidelink-based relay functionality was studied for extending sidelink / network coverage and improving power efficiency. The "Study on NR Sidelink Relay" was conducted in a previous phase of Rel. 17 and included enhancements and solutions necessary to support the extension of UE network-to-network relay coverage. The results of the sidelink relay study are documented in 3GPP Technical Report ("TR") 38.836.

[0028] Remote UEs, like direct Uu UEs, need to be connected via Radio Resource Control ("RRC") to access network services, such as initiating a voice call or starting a data service. For this purpose, RRC-idle remote UEs need to establish an RRC connection, RRC-inactive remote UEs need to reactivate an RRC connection, and in the event of a Radio Link failure ("RLF"), remote UEs may need to re-establish an RRC connection. On the Uu interface for the direct link between the UE and the 5G / NR node B ("gNB"), these three procedures are managed using three respective timers T300, T319, and T301, respectively.

[0029] Since time management is also required for remote UEs to perform these procedures, it was agreed to introduce new fields into SIB1 for timers like T300, T319, and T301 used by L2 remote UEs. For these timers, in addition to the existing stop conditions for legacy timers, further stop conditions for relayed scenarios will be added: "(re)selected relay becomes unsuitable" for timers like T300, "(re)selection of relay" for timers like T319, and "(re)selected relay becomes unsuitable" for timers like T301.

[0030] It was also agreed not to introduce a new timer like the T311 for L2 remote UEs. Instead, an additional stop condition will be added to the legacy T311 timer for relayed scenarios: "when the appropriate relay is (re)selected".

[0031] The agreement proposes adding three new timers to SIB1 for the aforementioned purposes, and if we consider that information elements ("IE") similar to UE-TimersAndConstants (i.e., defined as part of the definition of SIB1 in 3GPP Technical Specification ("TS") 38.331 (v16.6.0)) for sidelinks ("SL") should be optionally introduced, the addition of timers would increase the SIB1 signaling by at least 9 bits, or even 10 bits.

[0032] SIB1 is a cell-specific System Information Block ("SIB") that contains information relevant when evaluating whether a UE is allowed to access a cell and defines the scheduling of other system information. SIB1 also includes radio resource configuration information common to all UEs, and barring information that applies to unified access control. In 3GPP, SIB1 is associated with a Broadcast Control Channel (BCCH) logical channel.

[0033] As specified in Section 13 of 3GPP TS 38.213, SIB1 is transmitted over the downlink shared channel ("DL-SCH") (transport channel) with a period of 160 ms and a variable transmit repetition period of up to 160 ms, making SIB1 scheduling very expensive. The default transmit repetition period for SIB1 is 20 ms, but the actual transmit repetition period depends on the network implementation. For Synchronization Signal Block ("SSB") and Control Resource Set ("CORESET") multiplexing pattern 1, the transmit repetition period for SIB1 is 20 ms. For SSB and CORESET multiplexing patterns 2 / 3, the transmit repetition period for SIB1 is the same as the SSB period (see Section 13 of 3GPP TS 38.213). SIB1 includes an indication of whether one or more System Information Blocks ("SIBs") are provided only on demand, and if so, the configuration required by the UE to fulfill the System Information ("SI") request, along with other information regarding the availability and scheduling of the SIBs (e.g., the mapping of the SIBs to SI messages, the period, the SI window size).

[0034] Therefore, adding 10 bits to the SIB1 signaling is generally not advisable, especially when beam sweeping needs to be used by the base station for SIB1 transmission. This disclosure provides an alternative solution.

[0035] Figure 1 shows a wireless communication system 100 for configuring a sidelink connection timer according to an embodiment of the present disclosure. In one embodiment, the wireless communication system 100 includes at least one remote unit 105, a radio access network ("RAN") 120, and a mobile core network 140. The RAN 120 and the mobile core network 140 form a mobile communication network. The RAN 120 may consist of a base unit 121 with which the remote unit 105 communicates using a wireless communication link 123. Although a specific number of remote units 105, base units 121, wireless communication links 123, RAN 120, and mobile core network 140 are shown in Figure 1, a person skilled in the art will recognize that any number of remote units 105, base units 121, wireless communication links 123, RAN 120, and mobile core network 140 may be included in the wireless communication system 100.

[0036] In one implementation, RAN 120 conforms to a fifth-generation ("5G") system as defined in the 3GPP specification. For example, RAN 120 may be a next-generation radio access network ("NG-RAN") implementing NR radio access technology ("RAT") and / or Long-Term Evolution ("LTE") RAT. In another example, RAN 120 may include a non-3GPP RAT (e.g., Wi-Fi® or a WLAN conforming to the IEEE 802.11 family). In yet another implementation, RAN 120 conforms to an LTE system as defined in the 3GPP specification. However, more broadly, the wireless communication system 100 may implement any other open or proprietary communication network, among other things, such as Worldwide Interoperability for Microwave Access ("WiMAX") or standards of the IEEE 802.16 family. This disclosure is not intended to be limited to any specific wireless communication system architecture or protocol implementation.

[0037] In one embodiment, the remote unit 105 may include computing devices such as desktop computers, laptop computers, personal digital assistants ("PDAs"), tablet computers, smartphones, smart televisions (e.g., Internet-connected televisions), smart home appliances (e.g., Internet-connected home appliances), set-top boxes, game consoles, security systems (including security cameras), in-vehicle computers, and network devices (e.g., routers, switches, modems). In some embodiments, the remote unit 105 includes wearable devices such as smartwatches, fitness bands, and optical head-mounted displays. Furthermore, the remote unit 105 may be referred to as a UE, subscriber unit, mobile phone, mobile station, user, terminal, mobile terminal, fixed terminal, subscriber station, user terminal, wireless transmit / receive unit ("WTRU"), device, or other terms used in the art.

[0038] In various embodiments, the remote unit 105 includes a subscriber identity and / or identification module ("SIM") and a mobile device ("ME") that provides mobile termination functions (e.g., radio transmission, handover, voice coding and decoding, error detection and correction, signaling, and access to the SIM). In certain embodiments, the remote unit 105 may include a terminal device ("TE") and / or be incorporated into a consumer electronics or device (e.g., the computing device described above). The remote unit 105 enables a user to access network services. In various embodiments, the interface between the remote unit 105 and the network is a radio interface. The remote unit 105 may be subdivided into several domains, which are separated by a reference point. For example, the remote unit 105 may be subdivided into a Universal Integrated Circuit Card ("UICC") domain and an ME domain. The ME domain may be further subdivided into one or more Mobile Termination ("MT") and TE components with connections between multiple functional groups.

[0039] The remote unit 105 may communicate directly with one or more base units 121 in the RAN 120 by uplink ("UL") and downlink ("DL") communication signals. Furthermore, the UL and DL communication signals may be carried over a wireless communication link 123. In addition, the UL communication signals may include one or more uplink channels, such as a physical uplink control channel ("PUCCH") and / or a physical uplink sharing channel ("PUSCH"), while the DL communication signals may include one or more DL channels, such as a physical downlink control channel ("PDCCH") and / or a physical downlink sharing channel ("PDSCH"). Here, the RAN 120 is an intermediate network that provides the remote unit 105 with access to the mobile core network 140.

[0040] In various embodiments, remote units 105 may communicate directly with each other using a sidelink communication link 115 (for example, device-to-device communication). Here, sidelink transmissions may take place over sidelink resources. Remote units 105 may be provided with different sidelink communication resources according to different allocation modes. As used herein, “resource pool” refers to a set of resources allocated for sidelink operation. A resource pool consists of a set of resource blocks (i.e., physical resource blocks ("PRBs")) on one or more time units (e.g., orthogonal frequency division multiplexing ("OFDM") symbols, subframes, slots, subslots, etc.). In some embodiments, the set of resource blocks includes a contiguous PRB in the frequency domain. As used herein, a PRB consists of 12 contiguous subcarriers in the frequency domain.

[0041] In some embodiments, the remote unit 105 communicates with the application server 151 via a network connection to the mobile core network 140. For example, an application 107 within the remote unit 105 (e.g., a web browser, media client, telephone, and / or Voice over Internet Protocol ("VoIP") application) may trigger the remote unit 105 to establish a Protocol Data Unit ("PDU") session (or Packet Data Network ("PDN") connection) with the mobile core network 140 via the RAN 120. The PDU session represents a logical connection between the remote unit 105 and the User Plane Function ("UPF") 141. The mobile core network 140 then uses the PDU session (or other data connection) to relay traffic between the remote unit 105 and the application server 151 in the Packet Data Network 150.

[0042] To establish a PDU session (or PDN connection), the remote unit 105 must register with the mobile core network 140 (also referred to as "attaching to the mobile core network" in the context of fourth-generation ("4G") systems). Note that the remote unit 105 may establish one or more PDU sessions (or other data connections) with the mobile core network 140. Thus, the remote unit 105 may have at least one PDU session for communicating with the packet data network 150. The remote unit 105 may establish additional PDU sessions for communicating with other data networks and / or other communication peers.

[0043] 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 a remote unit 105 and a specific data network ("DN") via UPF 141. A PDU session supports one or more quality of service ("QoS") flows. In certain embodiments, a one-to-one mapping may exist between QoS flows and QoS profiles such that all packets belonging to a particular QoS flow have the same 5G QoS identifier ("5QI").

[0044] In the context of 4G / LTE systems such as Evolved Packet Systems ("EPS"), a PDN connection (also called an EPS session) provides an E2E UP connection between a remote unit and the PDN. The PDN connection procedure establishes a tunnel between the EPS bearer, i.e., the remote unit 105, and the PDN gateway ("PGW") (not shown in Figure 1) in the mobile core network 140. In certain embodiments, a one-to-one mapping exists between the EPS bearer and the QoS profile such that all packets belonging to a particular EPS bearer have the same QoS class identifier ("QCI").

[0045] The base units 121 may be geographically distributed. In certain embodiments, the base units 121 may also be referred to as access terminals, access points, bases, base stations, node B ("NB"), evolved node B (abbreviated as eNodeB or "eNB," also known as Evolved Universal Terrestrial Radio Access Network ("E-UTRAN") node B), gNB, home node B, relay node, RAN node, or any other term used in the art. The base units 121 are generally part of a RAN, such as RAN 120, which may include one or more controllers coupled to one or more corresponding base units 121 for communication. These and other elements of the radio access network are not shown but are generally well known to those skilled in the art. The base units 121 connect to the mobile core network 140 via RAN 120.

[0046] The base unit 121 may serve a number of remote units 105 within a serving area, for example, a cell or a sector of a cell, via a wireless communication link 123. The base unit 121 may communicate directly with one or more of the remote units 105 by communication signals. Generally, the base unit 121 transmits DL communication signals to serve the remote units 105 in the time, frequency, and / or spatial domains. Furthermore, the DL communication signals may be carried over the wireless communication link 123. The wireless communication link 123 may be any suitable carrier of the radio spectrum, whether licensed or unlicensed. The wireless communication link 123 facilitates communication between one or more of the remote units 105 and / or one or more of the base units 121.

[0047] Note that during NR operation on an unlicensed spectrum (referred to as "NR-U"), the base unit 121 and the remote unit 105 communicate over an unlicensed (i.e., shared) radio spectrum. Similarly, during LTE operation on an unlicensed spectrum (referred to as "LTE-U"), the base unit 121 and the remote unit 105 also communicate over an unlicensed (i.e., shared) radio spectrum.

[0048] In one embodiment, the mobile core network 140 is a 5G core network ("5GC") or evolved packet core ("EPC") which may be coupled to a packet data network 150, such as the Internet and a private data network, among other data networks. The remote unit 105 may be subscribed to or otherwise accounted for by the mobile core network 140. In various embodiments, each mobile core network 140 belongs to a single mobile network operator ("MNO") and / or a public land mobile network ("PLMN"). This disclosure is not intended to be limited to any particular wireless communication system architecture or protocol implementation.

[0049] The mobile core network 140 includes several network functions ("NF"). As shown, the mobile core network 140 includes at least one UPF 141. The mobile core network 140 also includes several control plane ("CP") functions, including but not limited to the Access and Mobility Management Function ("AMF") 143, Session Management Function ("SMF") 145, Policy Control Function ("PCF") 147, Unified Data Management Function ("UDM"), and User Data Repository ("UDR"), also known as Unified Data Repository, which serve the RAN 120. While certain numbers and types of network functions are shown in Figure 1, those skilled in the art will acknowledge that any number and types of network functions may be included in the mobile core network 140.

[0050] UPF 141 is responsible for routing and forwarding packets for interconnecting data networks ("DNs") in a 5G architecture, packet inspection, QoS processing, and external PDU sessions. AMF 143 is responsible for terminating non-access layer ("NAS") signaling, NAS encryption and integrity protection, registration management, connectivity management, mobility management, access authentication and authorization, and security context management. SMF 145 is responsible for session management (i.e., session establishment, modification, and release), allocation and management of Internet Protocol ("IP") addresses for remote units (i.e., UEs), DL data notification, and traffic steering configuration for UPF 141 for proper traffic routing.

[0051] PCF 147 is responsible for a unified policy framework, providing policy rules to CP functions, and access enrollment information for policy decisions in the UDR. The UDM is responsible for generating Authentication and Key Agreement ("AKA") credentials, user identification processing, access authorization, and enrollment management. The UDR is a repository of enrollment information and may be used to serve many network functions. For example, the UDR may store enrollment data, policy-related data, and enrollment-related data that may be exposed to third-party applications. In some embodiments, the UDM is located in the same place as the UDR and is shown as a combined entity "UDM / UDR" 149.

[0052] In various embodiments, the mobile core network 140 may also include a Network Repository Function ("NRF") (which provides registration and discovery of Network Function ("NF") services, enabling NFs to identify appropriate services from one another and communicate with each other via Application Programming Interfaces ("APIs")), a Network Exposure Function ("NEF") (which is responsible for ensuring that network data and resources are readily accessible to customers and network partners), an Authentication Server Function ("AUSF"), or other NFs defined for 5GC. Where present, the AUSF may act as an Authentication Server and / or Authentication Proxy, thereby enabling the AMF 143 to authenticate the remote unit 105. In certain embodiments, the mobile core network 140 may also include an Authentication, Authorization, and Accounting ("AAA") server.

[0053] In various embodiments, the mobile core network 140 supports different types of mobile data connections and different types of network slices, with each mobile data connection utilizing a specific network slice. Here, “network slice” refers to a portion of the mobile core network 140 optimized for a particular type of traffic or communication service. For example, one or more network slices may be optimized for enhanced mobile broadband (eMBB) services. Another example is that one or more network slices may be optimized for ultra-high reliability low latency (URLLC) services. In other examples, network slices may be optimized for machine-type communication (MTC) services, massive MTC (mMTC) services, or Internet of Things (IoT) services. In yet another example, network slices may be deployed for specific application services, vertical services, or specific use cases.

[0054] Network slice instances may be identified by single-network slice selection assistance information ("S-NSSAI"), while the set of network slices authorized for use by the remote unit 105 is identified by network slice selection assistance information ("NSSAI"). Here, "NSSAI" refers to a vector value containing one or more S-NSSAI values. In certain embodiments, various network slices may contain separate instances of network functions such as SMF 145 and UPF 141. In some embodiments, different network slices may share some common network functions such as AMF 143. For simplicity of illustration, different network slices are not shown in Figure 1, but their support is assumed.

[0055] To facilitate the configuration of the sidelink connection timers, the base unit 121 may transmit the sidelink configuration to the remote unit 105, which uses the sidelink configuration to identify the associated sidelink connection timers and / or associated sidelink communication resources. In various embodiments, the sidelink configuration may be transmitted within an SI such as SIB1 or another SIB containing the sidelink configuration information.

[0056] In various embodiments, the remote unit 105 may be provided with different sidelink communication resources for different allocation modes. Mode 1 corresponds to a sidelink communication mode scheduled by an NR-based network, where the RAN 120 in coverage indicates resources for use in sidelink operation, including resources from one or more resource pools. Mode 2 corresponds to a sidelink communication mode scheduled by an NR-based UE (i.e., UE autonomous selection), where the remote unit 105 selects resource pools and resources within them from a set of candidate pools. Mode 3 corresponds to a sidelink communication mode scheduled by an LTE-based network. Mode 4 corresponds to a sidelink communication mode scheduled by an LTE-based UE (i.e., UE autonomous selection).

[0057] Figure 1 shows the components of a 5G RAN and 5G core network, but the described embodiments for configuring the sidelink connection timer apply to other types of communication networks and RATs, including variants of IEEE 802.11, the Global System for Mobile Communications ("GSM") (i.e., 2G digital cellular networks), General Purpose Packet Radio Service ("GPRS"), Universal Mobile Communications System ("UMTS"), variants of LTE, CDMA2000, Bluetooth, ZigBee, Sigfox, and others.

[0058] Furthermore, in an LTE variant where the mobile core network 140 is the EPC, the network functions shown may be replaced by appropriate EPC entities such as a Mobility Management Entity ("MME"), Serving Gateway ("SGW"), PGW, and Home Subscriber Server ("HSS"). For example, the AMF 143 may be mapped to the MME, the SMF 145 to the control plane portion of the PGW and / or the MME, the UPF 141 to the user plane portions of the SGW and PGW, and the UDM / UDR 149 to the HSS.

[0059] In the following description, the term “RAN node” is used for base station / base unit, but it may be replaced by any other radio access node, such as gNB, ng-eNB, eNB, base station ("BS"), base station unit, access point ("AP"), NR BS, 5G NB, transmission and reception point ("TRP"), etc. Furthermore, the term “UE” is used for mobile station / remote unit, but it may be replaced by any other remote device, such as remote unit, MS, ME, etc.

[0060] Furthermore, the operation is primarily described in the context of 5G NR. However, the solutions / methods described below are also applicable to other mobile communication systems that constitute a sidelink connection timer.

[0061] Figure 2 shows an NR protocol stack 200 according to an embodiment of the present disclosure. Figure 2 shows a UE 205, a RAN node 210, and an AMF 215 in the 5G core network ("5GC"), which represent a set of remote units 105 that interact with the base unit 121 and the mobile core network 140. As shown, the NR protocol stack 200 includes a user plane protocol stack 201 and a control plane protocol stack 203. The user plane protocol stack 201 includes a physical ("PHY") layer 220, a medium access control ("MAC") sublayer 225, a radio link control ("RLC") sublayer 230, a packet data convergence protocol ("PDCP") sublayer 235, and a service data adaptation protocol ("SDAP") sublayer 240. The control plane protocol stack 203 includes the PHY layer 220, MAC sublayer 225, RLC sublayer 230, and PDCP sublayer 235. The control plane protocol stack 203 also includes the RRC layer 245 and the NAS layer 250.

[0062] The Access Layer ("AS") layer 255 (also known as the "AS protocol stack") of the user plane protocol stack 201 consists of at least the SDAP, PDCP, RLC, and MAC sublayers, as well as the physical layer. The AS layer 260 of the control plane protocol stack 203 consists of at least the RRC, PDCP, RLC, MAC sublayer, and the physical layer. Layer 2 ("L2") is divided into the SDAP, PDCP, RLC, and MAC sublayers. Layer 3 ("L3") includes the RRC layer 245 and NAS layer 250 of the control plane, and also includes, for example, the IP layer and / or PDU layer (not shown) of the user plane. L1 and L2 are referred to as "lower layers," while L3 and above (e.g., transport layer, application layer) are referred to as "higher layers" or "upper layers."

[0063] The PHY layer 220 provides a transport channel to the MAC sublayer 225. The PHY layer 220 may perform beam fault detection procedures using an energy detection threshold. In certain embodiments, the PHY layer 220 may transmit beam fault indications to the MAC entity of the MAC sublayer 225. The MAC sublayer 225 provides a logical channel to the RLC sublayer 230. The RLC sublayer 230 provides an RLC channel to the PDCP sublayer 235. The PDCP sublayer 235 provides radio bearers to the SDAP sublayer 240 and / or the RRC layer 245. The SDAP sublayer 240 provides QoS flows to the core network (e.g., 5GC). The RRC layer 245 provides functions for adding, modifying, and releasing carrier aggregation and / or dual connectivity. The RRC layer 245 also manages the establishment, configuration, maintenance, and release of signaling radio bearers ("SRBs") and data radio bearers ("DRBs").

[0064] The NAS layer 250 is located between the UE 205 and the AMF 215 within the 5GC. NAS messages are passed transparently through the RAN. The NAS layer 250 manages the establishment of communication sessions and is used to maintain continuous communication with the UE 205 as it moves between different cells in the RAN. In contrast, the AS layers 255 and 260 are located between the UE 205 and the RAN (i.e., the RAN node 210) and carry information through the wireless portion of the network. Although not shown in Figure 2, the IP layer is located above the NAS layer 250, the transport layer is located above the IP layer, and the application layer is located above the transport layer.

[0065] MAC sublayer 225 is the lowest sublayer in the L2 architecture of the NR protocol stack. MAC sublayer 225 is connected to the PHY layer 220 below via the transport channel, and to the RLC sublayer 230 above via the logical channel. Thus, MAC sublayer 225 performs multiplexing and multiplexing / demultiplexing between the logical channel and the transport channel; that is, the transmitting MAC sublayer 225 constructs a MAC PDU (also known as a transport block ("TB")) from MAC service data units ("SDU") received via the logical channel, and the receiving MAC sublayer 225 recovers a MAC SDU from a MAC PDU received via the transport channel.

[0066] The MAC sublayer 225 provides data transfer services for the RLC sublayer 230 via a logical channel that is either a control logic channel carrying control data (e.g., RRC signaling) or a traffic logic channel carrying user plane data. Meanwhile, data from the MAC sublayer 225 is exchanged with the PHY layer 220 via transport channels classified as UL or DL. The data is multiplexed onto the transport channels depending on how it is transmitted wirelessly in the air.

[0067] PHY layer 220 is responsible for the actual transmission of data and control information over the radio interface; that is, PHY layer 220 carries all information from the MAC transport channel over the transmitting radio interface. Some of the key functions performed by PHY layer 220 include coding and modulation, link adaptation (e.g., Adaptive Modulation and Coding ("AMC")), power control, cell discovery and random access (for initial synchronization and handover), and other measurements (within and between 3GPP systems (i.e., NR and / or LTE systems)) for RRC layer 245. PHY layer 220 performs transmission based on transmission parameters such as modulation scheme, coding rate (i.e., Modulation Coding Scheme ("MCS")), and PRB count.

[0068] U2N relays are a potential means of increasing the coverage of a serving cell, for example, by using one or more hops. Regarding U2N coverage extension, Uu coverage reachability is required for a UE to reach a server within the PDN network or a neighboring UE outside the immediate vicinity area. A U2N relay UE is an in-coverage implementation of UE 205 that extends the coverage of RAN node 210. Through the U2N relay UE, RAN node 210 can serve an otherwise out-of-coverage implementation of UE 205, called a U2N remote UE.

[0069] In some embodiments, the U2N relay UE functions as an L3 relay (also known as an IP relay). Here, communication between the RAN node 210 and the U2N remote UE via the L3 relay is via a Uu link (e.g., a first interface) between the RAN node 210 and the U2N relay UE, and a PC5 link (e.g., a second interface) between the U2N relay UE and the U2N remote UE. In such embodiments, the protocol stack of the U2N relay UE may include SDAP, RRC, PDCP, RLC, MAC, and PHY layers that interact with the corresponding layers of the RAN node 210 via the first interface (i.e., corresponding to the Uu link) and also interact with the corresponding layers of the U2N remote UE via the second interface (i.e., corresponding to the PC5 link).

[0070] In some embodiments, the U2N relay UE functions as an L2 relay. In certain embodiments, the U2N relay UE, acting as an L2 relay, performs relay functions under the PDCP sublayer 235, and therefore the U2N relay UE does not perform PDCP, RRC, and SDAP functions with respect to communication between the RAN node 210 and the U2N remote UE. In such embodiments, the protocol stack of the U2N relay UE may include RLC sublayer 230, MAC sublayer 225, and PHY layer 220 entities that interact with the corresponding layers of the RAN node 210 via a first interface and with the corresponding layers of the U2N remote UE via a second interface. However, with respect to the PDCP sublayer 235, SDAP sublayer 240, and RRC layer 245, the link endpoint is between the RAN node 210 and the U2N remote UE.

[0071] In some embodiments, the U2N relay UE functions as an L1 relay with HARQ functionality (also known as an Amplify and Forward relay). In certain embodiments, the protocol stack of the U2N relay UE may include a PHY layer 220 and HARQ entities (i.e., MAC sublayer 225) that interact with the corresponding layer of the RAN node 210 via a first interface and with the corresponding layer of the U2N remote UE via a second interface. However, with respect to the remaining layers, the link endpoint is between the RAN node 210 and the U2N remote UE.

[0072] The above description of relays is illustrative, and it should be noted that U2N relay UEs are not limited to the relay implementations described above. Therefore, U2N relay UEs may implement different protocol stacks and / or link endpoints than those described above, according to the solutions described below.

[0073] Figure 3 shows an exemplary procedure 300 for establishing an RRC connection according to an embodiment of the present disclosure. Procedure 300 includes a U2N sidelink remote UE (i.e., denoted as “remote UE”) 305 (for example, an instance of an out-of-coverage remote unit 105 or an out-of-coverage UE 205), a U2N sidelink relay UE (i.e., denoted as “relay UE”) 310 (for example, an instance of an in-coverage remote unit 105 or UE 205), and a RAN node 210 (for example, an instance of base unit 121). By procedure 300, the U2N sidelink remote UE 305 can acquire SIB1 (and optionally other SIBs) via the U2N sidelink relay UE 310 and initiate an RRC connection request with the RAN node 210.

[0074] In step 1, the U2N sidelink remote UE 305 receives SIB1 via the U2N sidelink relay UE 310 (see messaging 315). Optionally, the U2N sidelink remote UE 305 may also receive one or more additional SIBs (denoted as "SIB_X" in Figure 3) via the U2N sidelink relay UE 310. In various embodiments, the RAN node 210 broadcasts SIB1, and the U2N sidelink relay UE 310 relays SIB1 to the U2N sidelink remote UE 305, where it is assumed that SIB1 includes sidelink connection timer information, as described in more detail below. In certain embodiments, the RAN node 210 may also broadcast one or more additional SIBs. In other embodiments, one or more of the additional SIBs (i.e., SIB_X) may constitute an on-demand SIB, and the U2N sidelink relay UE 310 may request and receive additional SIBs from the RAN node 210 (not shown in Figure 3).

[0075] As used herein, “on-demand” SI refers to an SI that is not periodically broadcast by the RAN (i.e., by the RAN node 210). Rather, a requesting UE (e.g., a U2N sidelink relay UE 310) must request a specific SI from the RAN, at which point the RAN (i.e., the RAN node 210) will transmit the requested SI to the requesting UE (e.g., the U2N sidelink relay UE 310) in one or more SIBs.

[0076] In step 2, the U2N sidelink remote UE 305 determines the SL connection timer based on information in SIB1, for example (see block 320). Although Figure 3 mainly focuses on establishing the RRC connection, the step of receiving and / or determining the SL connection timer applies to sidelink-specific versions of all three timers T300, T301, and T319—also called the “SL connection timer.”

[0077] In step 3a, the U2N sidelink remote UE 305 sends a setup request message (e.g., RRCSetupRequest) to the U2N sidelink relay UE 310 (see messaging 325). In certain embodiments, the U2N sidelink remote UE 305 requests an RRC connection over the uplink shared channel ("UL-SCH"). In certain embodiments, the setup request message (e.g., RRCSetupRequest) includes establishment cause parameters. In step 3b, the U2N sidelink relay UE 310 forwards the setup request message (i.e., RRCSetupRequest) to the RAN node 210 (see messaging 330).

[0078] Note that the U2N sidelink remote UE 305 starts a sidelink-specific T300 connection timer when it sends a setup request message (e.g., RRCSetupRequest) (see block 335). When the sidelink-specific T300 connection timer expires, the U2N sidelink remote UE 305 takes the actions specified in section 5.3.3.7 of 3GPP TS 38.331(v16.6.0), including notifying the upper layer of the failure to establish the RRC connection.

[0079] In step 4a-1, the RAN node 210 sends a setup message (e.g., RRCSetup) to the U2N sidelink relay UE 310 (see messaging 340). The network then establishes the SRB and DRB based on the establishment cause parameters. In certain embodiments, the setup message is sent over the downlink shared channel ("DL-SCH"). In step 4a-2, the U2N sidelink relay UE 310 forwards the setup message (e.g., RRCSetup) to the U2N sidelink remote UE 305 (see messaging 345).

[0080] Alternatively, in step 4b-1, the RAN node 210 sends a rejection message (e.g., RRCReject) to the U2N sidelink relay UE 310 (see messaging 350). In step 4b-2, the U2N sidelink relay UE 310 forwards the rejection message (e.g., RRCReject) to the U2N sidelink remote UE 305 (see messaging 355).

[0081] In step 5a-1, the U2N sidelink remote UE 305 acknowledges the setup message by sending a connection complete message (e.g., RRCSetupComplete) to the U2N sidelink relay UE 310 (see messaging 360). In step 5a-2, the U2N sidelink relay UE 310 forwards the connection complete message (e.g., RRCSetupComplete) to the RAN node 210 (see messaging 365). The above messages and their contents are described in detail in 3GPP TS 38.331 (v16.6.0), which is incorporated herein by reference.

[0082] Figure 4 shows an exemplary procedure 400 for re-establishing an RRC connection according to an embodiment of the present disclosure. Procedure 400 includes a U2N sidelink remote UE (i.e., denoted as “remote UE”) 305, a U2N sidelink relay UE (i.e., denoted as “relay UE”) 310, and a RAN node 210. Procedure 400 allows the U2N sidelink remote UE 305 to acquire SIB1 (and optionally other SIBs) via the U2N sidelink relay UE 310 and re-establish an RRC connection with the RAN node 210. In various embodiments, the U2N sidelink remote UE 305 initiates procedure 400 for re-establishing an RRC connection when one of the following conditions is met: • When detecting a wireless link failure, or ·When handover fails, or When a mobility failure from E-UTRA occurs, · When there is an indication of a completeness check failure from a lower layer, When RRC CONNECTION RECONFIGURATION fails.

[0083] In step 1, the U2N sidelink remote UE 305 receives SIB1 via the U2N sidelink relay UE 310 (see messaging 405). Optionally, the U2N sidelink remote UE 305 may also receive one or more additional SIBs (denoted as "SIB_X" in Figure 4) via the U2N sidelink relay UE 310. In various embodiments, the RAN node 210 broadcasts SIB1, and the U2N sidelink relay UE 310 relays SIB1 to the U2N sidelink remote UE 305, where SIB1 is assumed to include sidelink connection timer information, as described in more detail below. In certain embodiments, the RAN node 210 may also broadcast one or more additional SIBs. In other embodiments, one or more of the additional SIBs (i.e., SIB_X) may constitute an on-demand SIB, and the U2N sidelink relay UE 310 may request and receive additional SIBs from the RAN node 210 (not shown in Figure 4).

[0084] In step 2, the U2N sidelink remote UE 305 determines the SL connection timer based on information in SIB1, for example (see block 410). Although Figure 4 mainly focuses on the re-establishment of the RRC connection, the step of receiving and / or determining the SL connection timer applies to the sidelink-specific versions of all three timers T300, T301, and T319.

[0085] In step 3a, the U2N sidelink remote UE 305 sends a re-establishment request message (e.g., RRCReestablishmentRequest) to the U2N sidelink relay UE 310 (see messaging 415). In a particular embodiment, the U2N sidelink remote UE 305 requests the re-establishment of the RRC connection via the UL-SCH. In a particular embodiment, the re-establishment request message (e.g., RRCReestablishmentRequest) includes re-establishment cause parameters. In step 3b, the U2N sidelink relay UE 310 forwards the re-establishment request message (i.e., RRCReestablishmentRequest) to the RAN node 210 (see messaging 420).

[0086] Note that the U2N sidelink remote UE 305 starts the sidelink-specific T301 connection timer when it sends a re-establishment request message (e.g., RRCReestablishmentRequest) (see block 425). When the sidelink-specific T301 connection timer expires, the U2N sidelink remote UE 305 takes the actions specified in section 5.3.11 of 3GPP TS 38.331, including becoming RRC_IDLE with release cause "RRC connection failure".

[0087] In step 4a-1, the RAN node 210 sends a re-establishment message (e.g., RRCReestablishment) to the U2N sidelink relay UE 310 (see messaging 430). In some embodiments, the network re-establishes the SRB and DRB based on the re-establishment cause parameters. In certain embodiments, the re-establishment message is sent over the downlink shared channel ("DL-SCH"). In step 4a-2, the U2N sidelink relay UE 310 forwards the re-establishment message (e.g., RRCReestablishment) to the U2N sidelink remote UE 305 (see messaging 435).

[0088] Alternatively, a fallback to RRC establishment may be required in response to the re-establishment message. In step 4b-1, the RAN node 210 sends a setup message (e.g., RRCSetup) to the U2N sidelink relay UE 310 (see messaging 440). The network then establishes the SRB and DRB based on the re-establishment cause parameters. In certain embodiments, the setup message is sent via DL-SCH. In step 4b-2, the U2N sidelink relay UE 310 forwards the setup message (e.g., RRCSetup) to the U2N sidelink remote UE 305 (see messaging 445).

[0089] In step 5a-1, the U2N sidelink remote UE 305 acknowledges the re-establishment message by sending a re-establishment complete message (e.g., RRCReestablishmentComplete) to the U2N sidelink relay UE 310 (see messaging 450). In step 5a-2, the U2N sidelink relay UE 310 forwards the re-establishment complete message (e.g., RRCReestablishmentComplete) to the RAN node 210 (see messaging 455).

[0090] In an alternative where a fallback to RRC establishment is required, in step 5b-1, the U2N sidelink remote UE 305 acknowledges the setup message by sending a connection complete message (e.g., RRCSetupComplete) to the U2N sidelink relay UE 310 (see messaging 460). In step 5b-2, the U2N sidelink relay UE 310 forwards the connection complete message (e.g., RRCSetupComplete) to the RAN node 210 (see messaging 465). The above messages and their contents are described in detail in 3GPP Technical Specification ("TS") 38.331.

[0091] Figure 5 shows an exemplary procedure 500 for resuming an RRC connection according to an embodiment of the present disclosure. Procedure 500 includes a U2N sidelink remote UE (i.e., denoted as “remote UE”) 305, a U2N sidelink relay UE (i.e., denoted as “relay UE”) 310, and a RAN node 210. Procedure 500 allows the U2N sidelink remote UE 305 to acquire SIB1 (and optionally other SIBs) via the U2N sidelink relay UE 310 and resume the interrupted RRC connection with the RAN node 210. In various embodiments, the U2N sidelink remote UE 305 initiates procedure 500 when an upper layer or AS layer requests the resumption of an interrupted RRC connection (for example, when the U2N sidelink remote UE 305 is in the RRC_INACTIVE state, responds to RAN paging, or triggers an update of a RAN-based Notification Area).

[0092] In step 1, the U2N sidelink remote UE 305 receives SIB1 via the U2N sidelink relay UE 310 (see messaging 505). Optionally, the U2N sidelink remote UE 305 may also receive one or more additional SIBs (denoted as "SIB_X" in Figure 5) via the U2N sidelink relay UE 310. In various embodiments, the RAN node 210 broadcasts SIB1, and the U2N sidelink relay UE 310 relays SIB1 to the U2N sidelink remote UE 305, where SIB1 is assumed to include sidelink connection timer information, as described in more detail below. In certain embodiments, the RAN node 210 may also broadcast one or more additional SIBs. In other embodiments, one or more of the additional SIBs (i.e., SIB_X) may constitute an on-demand SIB, and the U2N sidelink relay UE 310 may request and receive additional SIBs from the RAN node 210 (not shown in Figure 5).

[0093] In step 2, the U2N sidelink remote UE 305 determines the SL connection timer based on information in SIB1, for example (see block 510). Although Figure 5 mainly focuses on the resumption of the RRC connection, the step of receiving and / or determining the SL connection timer applies to the sidelink-specific versions of all three timers T300, T301, and T319.

[0094] In step 3a, the U2N sidelink remote UE 305 sends a restart request message (e.g., RRCResumeRequest or RRCResumeRequest1) to the U2N sidelink relay UE 310 (see messaging 515). In certain embodiments, the U2N sidelink remote UE 305 requests the restart of the RRC connection via the UL-SCH. In certain embodiments, the restart request message (e.g., RRCResumeRequest or RRCResumeRequest1) includes restart cause parameters. In step 3b, the U2N sidelink relay UE 310 forwards the restart request message (i.e., RRCResumeRequest or RRCResumeRequest1) to the RAN node 210 (see messaging 520).

[0095] Note that the U2N sidelink remote UE 305 starts the sidelink-specific T319 connection timer when it sends a restart request message (e.g., RRCResumeRequest or RRCResumeRequest1) (see block 525). When the sidelink-specific T319 connection timer expires, the U2N sidelink remote UE 305 takes the actions specified in section 5.3.13.5 of 3GPP TS 38.331, including becoming RRC_IDLE with release cause "RRC connection failure".

[0096] In step 4a-1, the RAN node 210 sends a restart message (e.g., RRCResume) to the U2N sidelink relay UE 310 (see messaging 530). In some embodiments, the network restarts the SRB and DRB based on the restart cause parameter. In certain embodiments, the restart message is sent over the downlink shared channel ("DL-SCH"). In step 4a-2, the U2N sidelink relay UE 310 forwards the restart message (e.g., RRCResume) to the U2N sidelink remote UE 305 (see messaging 535).

[0097] Alternatively, in response to a restart message, a fallback to establishing an RRC may be required. In step 4b-1, the RAN node 210 sends a setup message (e.g., RRCSetup) to the U2N sidelink relay UE 310 (see messaging 540). The network then establishes the SRB and DRB based on the restart cause parameters. In certain embodiments, the setup message is sent via DL-SCH. In step 4b-2, the U2N sidelink relay UE 310 forwards the setup message (e.g., RRCSetup) to the U2N sidelink remote UE 305 (see messaging 545).

[0098] In step 5a-1, the U2N sidelink remote UE 305 acknowledges the restart message by sending a restart complete message (e.g., RRCResumeComplete) to the U2N sidelink relay UE 310 (see messaging 550). In step 5a-2, the U2N sidelink relay UE 310 forwards the restart complete message (e.g., RRCResumeComplete) to the RAN node 210 (see messaging 555).

[0099] In an alternative where a fallback to RRC establishment is required, in step 5b-1, the U2N sidelink remote UE 305 acknowledges the setup message by sending a connection complete message (e.g., RRCSetupComplete) to the U2N sidelink relay UE 310 (see messaging 560). In step 5b-2, the U2N sidelink relay UE 310 forwards the connection complete message (e.g., RRCSetupComplete) to the RAN node 210 (see messaging 565). The above messages and their contents are described in detail in 3GPP Technical Specification ("TS") 38.331.

[0100] Figure 6 shows an exemplary procedure 600 for resuming an RRC connection, followed by a network-initiated release, according to an embodiment of the present disclosure. Procedure 600 includes a U2N sidelink remote UE (i.e., denoted as “remote UE”) 305, a U2N sidelink relay UE (i.e., denoted as “relay UE”) 310, and a RAN node 210. Procedure 600 allows the U2N sidelink remote UE 305 of the U2N sidelink to request that it acquire SIB1 (and optionally other SIBs) via the U2N sidelink relay UE 310 and resume the interrupted RRC connection with the RAN node 210. However, in procedure 600, the network (i.e., the RAN node 210) initiates an RRC connection release procedure to transition the U2N sidelink remote UE 305 of the U2N sidelink from a connected state (e.g., RRC_CONNECTED state) to an unconnected state (e.g., RRC_IDLE state). As discussed above, the U2N sidelink remote UE 305 of a U2N sidelink may initiate the procedure when the upper layer or AS layer requests the resumption of a suspended RRC connection.

[0101] In step 1, the U2N sidelink remote UE 305 of the U2N sidelink receives SIB1 via the U2N sidelink relay UE 310 (see messaging 605). Optionally, the U2N sidelink remote UE 305 of the U2N sidelink may also receive one or more additional SIBs (denoted as "SIB_X" in Figure 6) via the U2N sidelink relay UE 310. In various embodiments, the RAN node 210 broadcasts SIB1, and the U2N sidelink relay UE 310 relays SIB1 to the U2N sidelink remote UE 305 of the U2N sidelink, where it is assumed that SIB1 includes sidelink connection timer information, as will be described in more detail below. In certain embodiments, the RAN node 210 may also broadcast one or more additional SIBs. In other embodiments, one or more of the additional SIBs (i.e., SIB_X) may constitute an on-demand SIB, and the U2N sidelink relay UE 310 may request and receive additional SIBs from the RAN node 210 (not shown in Figure 6).

[0102] In step 2, the U2N sidelink remote UE 305 of the U2N sidelink determines the SL connection timer based on information in SIB1, for example (see block 610). Although Figure 6 mainly focuses on the resumption of the RRC connection, the step of receiving and / or determining the SL connection timer applies to the sidelink-specific versions of all three timers T300, T301, and T319.

[0103] In step 3a, the U2N sidelink remote UE 305 of the U2N sidelink sends a restart request message (e.g., RRCResumeRequest or RRCResumeRequest1) to the U2N sidelink relay UE 310 (see messaging 615). In certain embodiments, the U2N sidelink remote UE 305 of the U2N sidelink requests the restart of the RRC connection via the UL-SCH. In certain embodiments, the restart request message (e.g., RRCResumeRequest or RRCResumeRequest1) includes restart cause parameters. In step 3b, the U2N sidelink relay UE 310 forwards the restart request message (i.e., RRCResumeRequest or RRCResumeRequest1) to the RAN node 210 (see messaging 620).

[0104] Note that the U2N sidelink remote UE 305 of the U2N sidelink starts the sidelink-specific T319 connection timer when it sends a restart request message (e.g., RRCResumeRequest or RRCResumeRequest1) (see block 625). When the sidelink-specific T319 connection timer expires, the U2N sidelink remote UE 305 of the U2N sidelink performs the actions specified in section 6.3.11 of 3GPP TS 38.331, including becoming RRC_IDLE with release cause "RRC connection failure".

[0105] In step 4a-1, the RAN node 210 sends a release message (e.g., RRCRelease) to the U2N sidelink relay UE 310 (see messaging 630). The network then triggers the U2N sidelink remote UE 305 of the U2N sidelink to release the RRC connection and transition from a connected state (e.g., RRC_CONNECTED state) to an idle state (e.g., RRC_IDLE state). In step 4a-2, the U2N sidelink relay UE 310 forwards the release message (e.g., RRCRelease) to the U2N sidelink remote UE 305 of the U2N sidelink (see messaging 635).

[0106] Alternatively, in step 4b-1, the RAN node 210 sends a release message (e.g., RRCRelease) containing a suspend configuration to the U2N sidelink relay UE 310 (see messaging 640). Here, the release message (e.g., RRCRelease with suspend configuration) triggers the U2N sidelink remote UE 305 of the U2N sidelink to suspend the RRC connection and transition from the RRC_CONNECTED state to the RRC_IDLE state. In step 4b-2, the U2N sidelink relay UE 310 forwards the release message (e.g., RRCRelease) to the U2N sidelink remote UE 305 of the U2N sidelink (see messaging 645). The above messages and their contents are described in detail in 3GPP Technical Specification ("TS") 38.331.

[0107] According to the first embodiment of the solution, the SL connection timer is not signaled in SIB1, but instead is signaled in a different SIB, which may be, for example, SIB12 (carrying the NR sidelink communication configuration), SIB13 (carrying the vehicle-to-everything ("V2X") sidelink communication configuration as defined in 3GPP TS 36.331, where V2X communication includes both vehicle-to-vehicle ("V2V") and vehicle-to-infrastructure ("V2I")), SIB14 (carrying the V2X sidelink communication configuration as defined in 3GPP TS 36.331, which may be used in conjunction with the V2X sidelink communication configuration contained in SIB13), or an SIB containing other information required for the operation of the U2N relay.

[0108] In the context of Uu, the connection timer has the following related behaviors, as shown in Table 1.

[0109] [Table 1]

[0110] Figure 7 shows an exemplary Abstract Syntax Notation 1 ("ASN.1") representation of the ue-TimersAndConstants IE according to an embodiment of the present disclosure. The Uu-specific connection timers are broadcast in SIB1 within the IE called ue-TimersAndConstants shown in Figure 7. The SL connection timers in the context of the sidelink will have similar UE behavior, even if the procedure is performed using the U2N sidelink relay UE 310 to reach the RAN node 210 in both the UL and DL directions. As already shown, the connection timers required by the SL remote UE are T300, T301, and T319.

[0111] Figure 8 shows an exemplary ASN.1 representation of an IE including SL connection timers for an SL / PC5 interface according to an embodiment of the present disclosure. In certain embodiments, these SL connection timers may be signaled in an additional SIB different from SIB1, e.g., SIB12, SIB13, SIB14, or another SIB containing information required for the operation of the U2N relay. In one embodiment, an IE including connection timers (e.g., SL connection timers) and constants used by a U2N remote UE is called sl-UE-TimersAndConstants. In other embodiments, an IE including connection timers and constants used by a U2N remote UE for use by a sidelink remote UE (e.g., U2N sidelink remote UE 305 of a U2N sidelink) may be called by a different name. As already shown, the SL connection timers required by the SL remote UE include SL-specific T300, SL-specific T301, and SL-specific T319.

[0112] In one implementation of the first solution, the U2N sidelink relay UE 310 extracts the SL connection timers (i.e., from IE sl-UE-TimersAndConstants or a similar IE) and forwards this information, along with the contents of the other SIB1, to the U2N sidelink remote UE 305 of the U2N sidelink.

[0113] In another implementation of the first solution, the U2N sidelink relay UE 310 forwards the corresponding SIB to the U2N sidelink remote UE 305 of the U2N sidelink. In one embodiment, this is done, for example, in a Discovery message sent by the U2N sidelink relay UE 310, before the establishment of the PC5 RRC connection between the U2N sidelink remote UE 305 and the U2N sidelink relay UE 310. In another embodiment, the U2N sidelink relay UE 310 signals the SL connection timer to the U2N sidelink remote UE 305 of the U2N sidelink, for example, using a PC5 RRC reconfiguration message, after the PC5 RRC connection has been established.

[0114] The first solution has the advantage that the U2N sidelink remote UE 305 of the U2N sidelink can directly use the signaled values ​​without requiring any additional burden in SIB1. In some embodiments, the SL connection timers signaled in the additional SIB may be incomplete, i.e., one or more of the SL-specific T300, SL-specific T301, or SL-specific T319 may not be present in the additional SIB. In such embodiments, the missing SL-specific timers may be derived from the corresponding Uu-specific connection timers. In one embodiment, the values ​​of the Uu-specific connection timers are used as is for the SL-specific timers whose values ​​are missing from the additional SIB. In another embodiment, an offset is added to the values ​​of the Uu-specific connection timers, as described in the second solution.

[0115] According to a second embodiment of the solution, a sidelink remote UE (e.g., U2N sidelink remote UE 305 of a U2N sidelink) can receive SIB1 (and thereby UE-TimersAndConstants) and derive an SL connection timer value by adding a fixed offset (e.g., 50ms) called the "PC5 additional offset time" to the corresponding Uu timer. In some embodiments, the additional delay on the PC5 interface is constant with respect to all connection timers (T300, T301, T319, etc.). Therefore, from a signaling point of view, it is simply possible to use this offset for the Uu-specific connection timer. In some embodiments, the timer-specific additional delay is signaled to the SL remote UE, so that each SL-specific connection timer (e.g., SL-specific T300, SL-specific T301, and SL-specific T319) may have the same--or different--additional offset for the corresponding Uu-specific connection timer.

[0116] In one implementation of the second solution, the value of the PC5 additional time offset is predetermined and therefore requires no signaling. However, in the second implementation, to give the network some flexibility to take into account local radio conditions, congestion, mode 1 / mode 2 resource allocation, etc., the PC5 additional time offset may be determined by the network and signaled within SIB1.

[0117] Thus, the method for deriving the SL connection timer can minimize additional SIB1 signaling. In certain embodiments, the PC5 offset value is predetermined by specification so as to avoid additional SIB1 signaling.

[0118] In some embodiments, the PC5 additional time offset can have a limited value, and signaling flexibility can be satisfied with just one, two, or three bits. For example, some potential values ​​that require only one bit might be ms20 (i.e., corresponding to 20ms), ms50 (i.e., corresponding to 50ms), and other values ​​that require more bits may be added. In certain embodiments, the PC5 additional time offset can be signaled in SIB1 within the ue-TimersAndConstants IE.

[0119] Figures 9A and 9B show exemplary ASN.1 representations of SIB1, including the UE timer and constants for the Uu interface, and an additional time offset for the SL interface. In the example shown, the additional time offset is signaled using two bits of SIB1.

[0120] In Figure 9B, the parameter Sl-AdditionalOffsetTimer-r17 uses 2 bits to indicate the value of the PC5 additional time offset from an exemplary set {20ms, 50ms, 100ms, 200ms}. In other embodiments, the PC5 additional time offset may be signaled externally at the level of the main SIB1.

[0121] In another embodiment of the second solution, assuming that connection timers T300, T301, and T319 have values ​​of 100, 200, and 300 ms in the received SIB1, and the PC5 additional time offset is 50 ms, the corresponding SL connection timers would be as follows: ·SL-T300 = 100ms + 50ms = 150ms ·SL-T301 = 200ms + 50ms = 250ms ·SL-T319 = 300ms + 50ms = 350ms

[0122] In some embodiments, the network may calculate a time offset (PC5 additional time offset) as twice the worst-case time (UL and DL) it would take for a PC5 RRC message (e.g., 80 bits) to successfully travel between the U2N sidelink remote UE 305 and its U2N sidelink relay UE 310, for example, with approximately three PC5 retransmissions in each direction. The worst-case scenario must be defined under specific radio conditions and channel congestion (e.g., busy ratio) of the PC5 link and depends on the required connection establishment performance. The worst-case scenario may also depend on the resource allocation mode (mode 1 or mode 2) of the PC5 communication.

[0123] In one implementation, the U2N Sidelink Remote UE 305 of the sidelink (i.e., U2N Sidelink Remote UE 305 of the U2N Sidelink) starts RRC connection timers such as T300, T301, and T319 at a given offset, which is signaled in the SI or specified, for example, as outlined above. Here, the U2N Sidelink Remote UE 305 of the U2N Sidelink does not calculate a new RRC timer value based on the signaled offset, but reuses the originally signaled RRC timer value. In one particular implementation, the U2N Sidelink Remote UE 305 of the U2N Sidelink starts a new timer using a value set to the time offset value signaled in the SI (as shown above). When a new timer expires, the U2N sidelink remote UE 305 of the U2N sidelink will, if applicable, start the associated RRC timer, for example, T300, T301, or T319.

[0124] Figure 10 shows the U2N sidelink relay configuration 1000 between the U2N sidelink remote UE 305 (i.e., SL remote UE) and U2N sidelink relay UE 310 of the U2N sidelink, and the network (i.e., RAN node 210), and the associated connection timers. The Uu connection timer 1005, such as T301, is used to manage the connection procedure on the Uu link between the RAN node 210 and the U2N sidelink relay UE 310. The "PC5 additional time" offset 1010 is required to account for the additional delay between the U2N sidelink remote UE 305 (i.e., out-of-coverage SL UE) and the U2N sidelink relay UE 310 of the U2N sidelink. The SL connection timer value used by the U2N sidelink remote UE 305 of the U2N sidelink is also configurable and therefore under the control of the serving RAN node 210, since the original Uu connection timer 1005 is still under the network configuration.

[0125] According to the third embodiment of the solution, two values ​​are used for each SL connection timer, rather than just one. The first of these two values ​​is used when the U2N sidelink relay UE 310 is used in both the UL and DL directions, and the second value is used when the U2N sidelink relay UE 310 is used in only one of the UL and DL directions, and the other direction uses a direct connection between the U2N sidelink remote UE 305 of the U2N sidelink and the RAN node 210. In some embodiments, the two values ​​of the SL connection timer are signaled to the U2N sidelink remote UE 305 of the U2N sidelink within SIB1 or an additional SIB (e.g., SIB12, SIB13, SIB14, or another SIB containing the information required for the operation of the U2N relay) -- as described in the embodiment of the first solution. In other embodiments, the two values ​​of the SL connection timer are derived from the Uu-specific connection timer and the PC5 additional time offset -- as described in the embodiment of the second solution.

[0126] Figure 11 shows a user device 1100 that may be used to configure a sidelink connection timer according to embodiments of the present disclosure. In various embodiments, the user device 1100 is used to implement one or more of the solutions described above. The user device 1100 may be one embodiment of a user endpoint such as the remote unit 105, UE 205, U2N sidelink remote UE 305, and / or U2N sidelink relay UE 310 described above. Furthermore, the user device 1100 may include a processor 1105, memory 1110, input device 1115, output device 1120, and transceiver 1125.

[0127] In some embodiments, the input device 1115 and the output device 1120 are combined into a single device such as a touchscreen. In certain embodiments, the user equipment 1100 may not include any input device 1115 and / or output device 1120. In various embodiments, the user equipment 1100 may include one or more of the processor 1105, memory 1110, and transceiver 1125, and may not include the input device 1115 and / or output device 1120.

[0128] As shown, the transceiver 1125 includes at least one transmitter 1130 and at least one receiver 1135. In some embodiments, the transceiver 1125 communicates with one or more cells (or wireless coverage areas) supported by one or more base units 121. In various embodiments, the transceiver 1125 is capable of operating in the unlicensed spectrum. Furthermore, the transceiver 1125 may include multiple UE panels supporting one or more beams. In addition, the transceiver 1125 may support at least one network interface 1140 and / or application interface 1145. The application interface 1145 may support one or more APIs. The network interface 1140 may support 3GPP reference points such as Uu, N1, PC5, etc. Other network interfaces 1140 may be supported, as will be understood by those skilled in the art.

[0129] In one embodiment, the processor 1105 may include any known controller capable of executing computer-readable instructions and / or logical operations. For example, the processor 1105 may be a microcontroller, microprocessor, central processing unit ("CPU"), graphics processing unit ("GPU"), auxiliary processing unit, field-programmable gate array ("FPGA"), or similar programmable controller. In some embodiments, the processor 1105 executes instructions stored in memory 1110 to perform the methods and routines described herein. The processor 1105 is coupled to communicate with memory 1110, input device 1115, output device 1120, and transceiver 1125.

[0130] In various embodiments, the processor 1105 controls the user device 1100 to perform the behavior of the UE described above. In certain embodiments, the processor 1105 may include an application processor (also known as the "main processor") that manages the functions of the application domain and the operating system ("OS"), and a baseband processor (also known as the "baseband radio processor") that manages the radio functions.

[0131] In various embodiments, via the transceiver 1125, the processor 1105 receives a set of connection timers (e.g., UE-TimersAndConstants IE) from the serving node's primary system information block (e.g., SIB1) transmission and a first set of sidelink connection timers (i.e., one or more sidelink connection timers) (e.g., sl-UE-TimersAndConstants or UE-TimersAndConstantsRemoteUE IE) from the serving node's additional system information block (e.g., SIB12, SIB13, SIB14, or another SIB containing information required for the operation of the U2N relay).

[0132] The processor 1105 determines a second set of sidelink connection timers for establishing communication with a network node (e.g., a gNB) using a U2N sidelink relay UE, and each value in the second set of sidelink connection timers is determined at least in part based on the first set of sidelink connection timers. Furthermore, the processor 1105 uses each connection timer to manage the establishment of communication with the network node via the U2N sidelink relay UE.

[0133] In some embodiments, the establishment of a managed communication includes one of the following: an RRC connection establishment procedure, an RRC connection reactivation procedure, or an RRC connection re-establishment procedure. In some embodiments, the processor 1105 starts the respective connection timer in response to the transmission of an RRC connection request, an RRC reactivation request, or an RRC connection re-establishment request by the transceiver 1125.

[0134] In some embodiments, the network node from which communication is initiated includes the current serving node or a non-serving network node. In some embodiments, a second set of sidelink connection timers for establishing communication includes (i.e., SL-specific) timers "T300", "T301", and "T319".

[0135] In some embodiments, each of at least one value in a second set of sidelink connection timers is determined based on a set of connection timers from the primary system information block (e.g., SIB1) (e.g., included in UE-TimersAndConstants IE).

[0136] In some embodiments, the processor 1105 determines the value of each of the second set of sidelink connection timers by using the corresponding timer values ​​of the first set of sidelink connection timers, if they are included in an additional system information block. Otherwise, in response to a corresponding timer value not present in the received first set of sidelink connection timers, the processor 1105 determines the missing value by using the timer value of the equivalent Uu connection timer from the primary system information block (e.g., SIB1).

[0137] In some embodiments, the primary system information block (e.g., SIB1) includes a UE-TimersAndConstants information element indicating a set of connection timers, and an additional system information block includes a UE-TimersAndConstantsRemoteUE information element indicating a first set of sidelink connection timers, and the additional system information block is different from the primary system information block (e.g., SIB1).

[0138] In some embodiments, the processor 1105 controls the transceiver 1125 to establish a sidelink (i.e., PC5) RRC connection with the U2N sidelink relay UE, and an SI, including at least a primary system information block (e.g., SIB1), is received in a discovery message received from the U2N sidelink relay UE before the sidelink RRC connection is established.

[0139] In some embodiments, the processor 1105 controls the transceiver 1125 to establish a sidelink (i.e., PC5) RRC connection with the U2N sidelink relay UE, and an SI, including at least a primary system information block (e.g., SIB1), is received in an RRC reconfiguration message received from the U2N sidelink relay UE after the sidelink RRC connection has been established.

[0140] In one embodiment, memory 1110 is a computer-readable storage medium. In some embodiments, memory 1110 includes a volatile computer storage medium. For example, memory 1110 may include RAM including dynamic RAM ("DRAM"), synchronous dynamic RAM ("SDRAM"), and / or static RAM ("SRAM"). In some embodiments, memory 1110 includes a non-volatile computer storage medium. For example, memory 1110 may include a hard disk drive, flash memory, or any other suitable non-volatile computer storage device. In some embodiments, memory 1110 includes both a volatile computer storage medium and a non-volatile computer storage medium.

[0141] In some embodiments, memory 1110 stores data related to configuring the sidelink connection timer. For example, memory 1110 may store the parameters, configurations, etc. In certain embodiments, memory 1110 also stores program code and related data, such as an operating system or other controller algorithms that run on the user equipment device 1100.

[0142] In one embodiment, the input device 1115 may include any known computer input device, such as a touch panel, buttons, a keyboard, a stylus, or a microphone. In some embodiments, the input device 1115 may be integrated with the output device 1120, for example, as a touchscreen or similar touch display. In some embodiments, the input device 1115 includes a touchscreen so that text may be entered using a virtual keyboard displayed on the touchscreen and / or by handwriting on the touchscreen. In some embodiments, the input device 1115 includes two or more different devices, such as a keyboard and a touch panel.

[0143] In one embodiment, the output device 1120 is designed to output visual, auditory, and / or tactile signals. In some embodiments, the output device 1120 includes an electronically controllable display or display device that can output visual data to a user. For example, the output device 1120 may include, but is not limited to, a liquid crystal display ("LCD"), a light-emitting diode ("LED") display, an organic LED ("OLED") display, a projector, or a similar display device that can output images, text, etc., to a user. In another non-limiting example, the output device 1120 may include a wearable display that is separate from the rest of the user equipment device 1100 but coupled to communicate with them, such as a smartwatch, smart glasses, or a head-up display. Furthermore, the output device 1120 may be a component of a smartphone, personal digital assistant, television, table computer, notebook (laptop) computer, personal computer, or vehicle dashboard.

[0144] In certain embodiments, the output device 1120 includes one or more speakers for generating sound. For example, the output device 1120 may generate an audible alert or notification (e.g., a beep or chime). In some embodiments, the output device 1120 includes one or more haptic devices for generating vibration, motion, or other tactile feedback. In some embodiments, all or part of the output device 1120 may be integrated with the input device 1115. For example, the input device 1115 and the output device 1120 may form a touchscreen or similar touch display. In other embodiments, the output device 1120 may be located near the input device 1115.

[0145] The transceiver 1125 communicates with one or more network functions of a mobile communication network via one or more access networks. The transceiver 1125 operates under the control of the processor 1105 to transmit and receive messages, data, and other signals. For example, the processor 1105 may selectively activate the transceiver 1125 (or a portion thereof) at specific times to send and receive messages.

[0146] The transceiver 1125 includes at least one transmitter 1130 and at least one receiver 1135. One or more transmitters 1130 may be used to provide a UL communication signal, such as a UL transmission as described herein, to the base unit 121. Similarly, one or more receivers 1135 may be used to receive a DL communication signal from the base unit 121, as described herein. Although only one transmitter 1130 and one receiver 1135 are illustrated, the user equipment device 1100 may have any suitable number of transmitters 1130 and receivers 1135. Furthermore, the transmitters 1130 and receivers 1135 may be any suitable type of transmitter and receiver. In one embodiment, the transceiver 1125 includes a first transmitter / receiver pair used to communicate with a mobile communication network over a licensed radio spectrum and a second transmitter / receiver pair used to communicate with a mobile communication network over an unlicensed radio spectrum.

[0147] In certain embodiments, a first transmitter / receiver pair used to communicate with a mobile communications network over a licensed radio spectrum, and a second transmitter / receiver pair used to communicate with a mobile communications network over an unlicensed radio spectrum, may be combined into a single transceiver unit, for example, a single chip that performs functions for use in both the licensed and unlicensed radio spectrums. In some embodiments, the first and second transmitter / receiver pairs may share one or more hardware components. For example, a particular transceiver 1125, transmitter 1130, and receiver 1135 may be implemented as physically separate components that access shared hardware and / or software resources, such as a network interface 1140.

[0148] In various embodiments, one or more transmitters 1130 and / or one or more receivers 1135 may be implemented and / or integrated into a single hardware component, such as a multi-transceiver chip, a system-on-a-chip, an application-specific integrated circuit ("ASIC"), or other types of hardware components. In certain embodiments, one or more transmitters 1130 and / or one or more receivers 1135 may be implemented and / or integrated into a multi-chip module. In some embodiments, other components, such as a network interface 1140 or other hardware components / circuits, may be integrated into a single chip together with any number of transmitters 1130 and / or receivers 1135. In such embodiments, the transmitters 1130 and receivers 1135 may be logically configured as transceivers 1125 using one or more common control signals, or as modular transmitters 1130 and receivers 1135 implemented within the same hardware chip or multi-chip module.

[0149] Figure 12 shows a network device 1200 that may be used to configure a sidelink connection timer according to embodiments of the present disclosure. In one embodiment, the network device 1200 may be one implementation of a network endpoint such as the base unit 121 and / or RAN node 210 described above. Furthermore, the network device 1200 may include a processor 1205, memory 1210, input device 1215, output device 1220, and transceiver 1225.

[0150] In some embodiments, the input device 1215 and the output device 1220 are combined into a single device such as a touchscreen. In certain embodiments, the network device 1200 may not include any input device 1215 and / or output device 1220. In various embodiments, the network device 1200 may include one or more of the processor 1205, memory 1210, and transceiver 1225, and may not include the input device 1215 and / or output device 1220.

[0151] As shown, the transceiver 1225 includes at least one transmitter 1230 and at least one receiver 1235, where the transceiver 1225 communicates with one or more remote units 105. In addition, the transceiver 1225 may support at least one network interface 1240 and / or application interface 1245. The application interface 1245 may support one or more APIs. The network interface 1240 may support 3GPP reference points such as Uu, N1, N2, and N3. Other network interfaces 1240 may be supported, as will be understood by those skilled in the art.

[0152] In one embodiment, the processor 1205 may include any known controller capable of executing computer-readable instructions and / or performing logical operations. For example, the processor 1205 may be a microcontroller, microprocessor, CPU, GPU, auxiliary processing unit, FPGA, or similar programmable controller. In some embodiments, the processor 1205 executes instructions stored in memory 1210 to perform the methods and routines described herein. The processor 1205 is coupled to communicate with memory 1210, input device 1215, output device 1220, and transceiver 1225.

[0153] In various embodiments, the network device 1200 is a RAN node (e.g., gNB) that communicates with one or more UEs, as described herein. In such embodiments, the processor 1205 controls the network device 1200 to perform the RAN behavior described above. When operating as a RAN node, the processor 1205 may include an application processor (also known as the “main processor”) that manages application domain and operating system (“OS”) functions, and a baseband processor (also known as the “baseband radio processor”) that manages radio functions.

[0154] In various embodiments, the processor 1205 identifies a set of SL-specific connection timers and transmits information about the set of SL-specific connection timers to at least one UE via the transceiver 1225. For example, device 1200 may transmit Uu-specific connection timers in SIB1 and further transmit SL-specific connection timers in additional SIBs. As another example, device 1200 may broadcast a time offset for use in deriving SL-specific connection timers from Uu-specific connection timers.

[0155] In some embodiments, the time offset includes a time value expressed in milliseconds used to manage the RRC connection establishment procedure by the remote UE in sidelink communication. In some embodiments, the time offset includes a time value expressed in milliseconds used to manage the RRC connection reactivation procedure by the remote UE in sidelink communication. In some embodiments, the time offset includes a time value expressed in milliseconds used to manage the RRC connection re-establishment procedure by the remote UE in sidelink communication.

[0156] In one embodiment, memory 1210 is a computer-readable storage medium. In some embodiments, memory 1210 includes a volatile computer storage medium. For example, memory 1210 may include RAM, including DRAM, SDRAM, and / or SRAM. In some embodiments, memory 1210 includes a non-volatile computer storage medium. For example, memory 1210 may include a hard disk drive, flash memory, or any other suitable non-volatile computer storage device. In some embodiments, memory 1210 includes both a volatile and a non-volatile computer storage medium.

[0157] In some embodiments, memory 1210 stores data related to configuring the sidelink connection timer. For example, memory 1210 may store the parameters, configurations, etc. In certain embodiments, memory 1210 also stores program code and related data, such as an operating system or other controller algorithms running on the network device 1200.

[0158] In one embodiment, the input device 1215 may include any known computer input device, such as a touch panel, buttons, a keyboard, a stylus, or a microphone. In some embodiments, the input device 1215 may be integrated with the output device 1220, for example, as a touchscreen or similar touch display. In some embodiments, the input device 1215 includes a touchscreen so that text may be entered using a virtual keyboard displayed on the touchscreen and / or by handwriting on the touchscreen. In some embodiments, the input device 1215 includes two or more different devices, such as a keyboard and a touch panel.

[0159] In one embodiment, the output device 1220 is designed to output visual, auditory, and / or tactile signals. In some embodiments, the output device 1220 includes an electronically controllable display or display device that can output visual data to a user. For example, the output device 1220 may include, but is not limited to, an LCD display, LED display, OLED display, projector, or similar display device that can output images, text, etc., to a user. In another non-limiting example, the output device 1220 may include a wearable display, such as a smartwatch, smart glasses, or head-up display, that is separate from but coupled to the rest of the network device 1200 so as to be able to communicate with them. Furthermore, the output device 1220 may be a component of a smartphone, personal digital assistant, television, table computer, notebook (laptop) computer, personal computer, or vehicle dashboard.

[0160] In certain embodiments, the output device 1220 includes one or more speakers for generating sound. For example, the output device 1220 may generate an audible alert or notification (e.g., a beep or chime). In some embodiments, the output device 1220 includes one or more haptic devices for generating vibration, motion, or other tactile feedback. In some embodiments, all or part of the output device 1220 may be integrated with the input device 1215. For example, the input device 1215 and the output device 1220 may form a touchscreen or similar touch display. In other embodiments, the output device 1220 may be located near the input device 1215.

[0161] The transceiver 1225 includes at least one transmitter 1230 and at least one receiver 1235. One or more transmitters 1230 may be used to communicate with the UE as described herein. Similarly, one or more receivers 1235 may be used to communicate with the network functions of the PLMN and / or RAN as described herein. Although only one transmitter 1230 and one receiver 1235 are illustrated, the network device 1200 may have any suitable number of transmitters 1230 and receivers 1235. Furthermore, the transmitters 1230 and receivers 1235 may be any suitable type of transmitter and receiver.

[0162] Figure 13 shows one embodiment of Method 1300 for configuring a sidelink connection timer according to embodiments of the present disclosure. In various embodiments, Method 1300 is performed by a communication device such as the remote unit 105, UE 205, and / or user equipment device 1100 described above. In some embodiments, Method 1300 is performed by a processor such as a microcontroller, microprocessor, CPU, GPU, auxiliary processing unit, FPGA, etc.

[0163] Method 1300 includes step 1305 of receiving a set of connection timers (e.g., UE-TimersAndConstants IE) from a first system information block (i.e., SIB1) transmission of the serving node. Method 1300 includes step 1310 of receiving a first set of sidelink connection timers (i.e., one or more sidelink connection timers) (e.g., sl-UE-TimersAndConstants IE) from an additional system information block of the serving node. Method 1300 includes step 1315 of determining a second set of sidelink connection timers for establishing communication with a network node using a UE inter-network sidelink relay UE, wherein the respective value of each timer in the second set of sidelink connection timers is determined at least in part on the first set of sidelink connection timers. Method 1300 includes step 1320 of using the respective connection timers to manage the establishment of communication with a network node via a U2N sidelink relay UE.

[0164] Disclosed herein is a first device for configuring a sidelink connection timer according to embodiments of the present disclosure. The first device may be implemented by communication devices such as the remote unit 105, UE 205, U2N sidelink remote UE 305 of the U2N sidelink, and / or user equipment device 1100. The first device includes a memory-coupled processor, the processor configured to cause the device to: A) receive a set of connection timers (e.g., UE-TimersAndConstants IE) from a first system information block (i.e., SIB1) transmission of a serving node; B) receive a first set of sidelink connection timers (i.e., one or more sidelink connection timers) (e.g., sl-UE-TimersAndConstants or UE-TimersAndConstantsRemoteUE IE) from an additional system information block of a serving node; C) determine a second set of sidelink connection timers for establishing communication with a network node using a U2N sidelink relay UE, wherein each value in the second set of sidelink connection timers is determined at least in part on the first set of sidelink connection timers; and D) use each connection timer to manage the establishment of communication with a network node via a U2N sidelink relay UE.

[0165] In some embodiments, the establishment of a managed communication includes one of the following: an RRC connection establishment procedure, an RRC connection reactivation procedure, or an RRC connection re-establishment procedure. In some embodiments, the processor is configured to start the respective connection timers of the device in response to the transmission of an RRC connection request, an RRC reactivation request, or an RRC connection re-establishment request.

[0166] In some embodiments, the network node from which communication is initiated includes the current serving node or a non-serving network node. In some embodiments, a second set of sidelink connection timers for establishing communication includes (i.e., SL-specific) timers "T300", "T301", and "T319".

[0167] In some embodiments, each of at least one value in a second set of sidelink connection timers is determined based on a set of connection timers from a first system information block (i.e., SIB1) (e.g., included in UE-TimersAndConstants IE).

[0168] In some embodiments, the processor is configured to cause the device to determine the values ​​of each of the second set of sidelink connection timers by using the corresponding timer values ​​of a first set of sidelink connection timers if they are included in an additional system information block, or by using the equivalent timer values ​​of the Uu connection timers from the first system information block if they are not (for example, in response to a corresponding timer value that is not present in the first set of sidelink connection timers received).

[0169] In some embodiments, the first system information block (i.e., SIB1) includes a UE-TimersAndConstants information element indicating a set of connection timers, and an additional system information block includes a UE-TimersAndConstantsRemoteUE information element indicating a first set of sidelink connection timers, and the additional system information block is different from the first system information block (i.e., SIB1).

[0170] In some embodiments, the processor is configured to cause the device to establish a sidelink (i.e., PC5) RRC connection with the U2N sidelink relay UE, and an SI including at least a first system information block (i.e., SIB1) is received in a discovery message received from the U2N sidelink relay UE before the establishment of the sidelink RRC connection.

[0171] In some embodiments, the processor is configured to cause the device to establish a sidelink (i.e., PC5) RRC connection with the U2N sidelink relay UE, and an SI including at least a first system information block (i.e., SIB1) is received in an RRC reconfiguration message received from the U2N sidelink relay UE after the establishment of the sidelink RRC connection.

[0172] Disclosed herein is a first method for configuring sidelink connection timers according to embodiments of the present disclosure. The first method may be performed by a communication device such as the remote unit 105, UE 205, U2N sidelink remote UE 305 of the U2N sidelink, and / or user equipment device 1100. The first method includes the steps of receiving a set of connection timers (e.g., UE-TimersAndConstants IE) from a first system information block (i.e., SIB1) transmission of a serving node, and receiving a first set of sidelink connection timers (i.e., one or more sidelink connection timers) (e.g., sl-UE-TimersAndConstants IE) from an additional system information block of the serving node. The first method includes determining a second set of sidelink connection timers for establishing communication with a network node using a UE inter-network sidelink relay UE, wherein the respective value of each timer in the second set of sidelink connection timers is determined at least in part on the first set of sidelink connection timers. The first method includes the step of using a respective connection timer to manage the establishment of communication with a network node via a U2N sidelink relay UE.

[0173] In some embodiments, establishing a managed communication includes one of the following: an RRC connection establishment procedure, an RRC connection reactivation procedure, or an RRC connection re-establishment procedure. In some embodiments, the first method includes the step of starting the respective connection timer in response to the transmission of an RRC connection request, an RRC reactivation request, or an RRC connection re-establishment request.

[0174] In some embodiments, the network node from which communication is initiated includes the current serving node or a non-serving network node. In some embodiments, a second set of sidelink connection timers for establishing communication includes (e.g., SL-specific) timers "T300", "T301", and "T319".

[0175] In some embodiments, each of at least one value in a second set of sidelink connection timers is determined based on a set of connection timers from a first system information block (i.e., SIB1) (e.g., included in UE-TimersAndConstants IE).

[0176] In some embodiments, the first method includes the step of determining the values ​​of each of the second set of sidelink connection timers by using the corresponding timer values ​​of a first set of sidelink connection timers if they are included in an additional system information block, or by using the equivalent timer values ​​of the Uu connection timers from the first system information block if they are not (for example, in response to a corresponding timer value that is not present in the received first set of sidelink connection timers).

[0177] In some embodiments, the first system information block (i.e., SIB1) includes a UE-TimersAndConstants IE indicating a set of connection timers, and an additional system information block includes an information element for a set of connection timers (i.e., sl-UE-TimersAndConstants or UE-TimersAndConstantsRemoteUE) indicating a first set of sidelink connection timers, and the additional system information block is different from the first system information block (i.e., SIB1).

[0178] In some embodiments, the first method is a step of establishing a sidelink (i.e., PC5) RRC connection with a U2N sidelink relay UE, wherein an SI including at least a first system information block (i.e., SIB1) is received in a discovery message received from the U2N sidelink relay UE prior to the establishment of the sidelink RRC connection.

[0179] In some embodiments, the first method includes the step of establishing a sidelink (i.e., PC5) RRC connection with a U2N sidelink relay UE, wherein an SI including at least a first system information block (i.e., SIB1) is received in an RRC reconfiguration message received from the U2N sidelink relay UE after the establishment of the sidelink RRC connection.

[0180] The embodiments may be carried out in other specific forms. The embodiments described should be considered illustrative in all respects only and not restrictive. Accordingly, the scope of the invention is indicated not by the above description but by the appended claims. All modifications that fall within the meaning and scope equivalent to the claims should be incorporated within the scope of the claims. [Explanation of Symbols]

[0181] 100 Wireless Communication Systems 105 Remote Unit 107 applications 115 Sidelink Communication Link 120 Wireless Access Network ("RAN") 121 Base Unit 123 Wireless communication link 140 Mobile Core Network 141 User Plane Function (UPF) 143 Access and Mobility Management Function (AMF) 145 Session Management Function (SMF) 147 Policy Control Function (PCF) 149 UDM / UDR 150 packet data network 151 Application Server 200 NR protocol stack 201 User Plane Protocol Stack 203 Control Plane Protocol Stack 205 UE 210 RANNode 215 AMF 220 Physical (PHY) Layers 225 MAC sublayer 230 Wireless Link Control (RLC) Sublayer 235 PDCP sublayer 240 Service Data Adaptive Protocol (SDAP) sublayer 245 Radio Resource Control (RRC) Layer 250 Non-Accessible Layer (NAS) 255 Access Layer (AS) 260 AS Layers 300 steps 305 U2N Sidelink Remote UE 310 U2N Side Link Relay UE 400 steps 500 steps 600 steps 1000 Side Link Relay Configuration 1005 Uu connection timer 1010 "PC5 Additional Time" Offset 1100 User equipment 1105 Processor 1110 memory 1115 Input Devices 1120 Output Device 1125 Transceiver 1130 Transmitter 1135 Receiver 1140 Network Interface 1145 Application Interface 1200 Network Devices 1205 Processor 1210 memory 1215 Input Devices 1220 Output Device 1225 Transceiver 1230 Transmitter 1235 Receiver 1240 Network Interfaces 1245 Application Interface 1300 methods

Claims

1. User equipment ("UE") for wireless communication, Memory and The processor is coupled to the memory, and the processor provides the UE Receiving a first system information block (SIB) indicating a set of connection timers, Receiving an additional SIB indicating a first set of sidelink connection timers, The determination of a second set of sidelink connection timers for establishing communication with network nodes via sidelink relay UE, Each value of the second set of sidelink connection timers is determined at least in part on the first set of sidelink connection timers and an additional time offset, the additional time offset is signaled within the first SIB, and User equipment ("UE") is configured to use its respective connection timer to manage the establishment of communication with the network node via the sidelink relay UE.

2. The UE according to claim 1, wherein the establishment of the managed communication includes one of the following: a Radio Resource Control ("RRC") connection establishment procedure, an RRC connection reactivation procedure, or an RRC connection re-establishment procedure.

3. The UE according to claim 1, wherein the processor is configured to cause the UE to start the respective connection timers in response to the transmission of a Radio Resource Control ("RRC") connection request, an RRC restart request, or an RRC connection re-establishment request.

4. The UE according to claim 1, wherein the network node on which the establishment of the aforementioned communication is initiated includes the current serving node or a non-serving network node.

5. The UE according to claim 1, wherein each of the values ​​of the second set of sidelink connection timers is determined based on the set of connection timers from the first system information block.

6. The UE according to claim 1, wherein the processor is configured to cause the UE to determine the respective values ​​of the second set of sidelink connection timers by using the corresponding timer values ​​of the first set of sidelink connection timers if the first set of sidelink connection timers is included in the additional system information block, and by using the equivalent timer values ​​of the Uu connection timers from the first system information block otherwise.

7. The UE according to claim 1, wherein the first system information block includes a UE-TimersAndConstants information element indicating the set of connection timers, and the additional system information block includes a UE-TimersAndConstantsRemoteUE information element for a set of connection timers indicating the first set of sidelink connection timers, and the additional system information block is different from the first system information block.

8. The UE according to claim 1, wherein the processor is configured to cause the UE to establish a sidelink radio resource control ("RRC") connection with the sidelink relay UE, and system information including at least the first system information block is received in a discovery message received from the sidelink relay UE before the establishment of the sidelink RRC connection.

9. The UE according to claim 1, wherein the processor is configured to cause the UE to establish a sidelink radio resource control ("RRC") connection with the sidelink relay UE, and system information including at least the first system information block is received in an RRC reconfiguration message received from the sidelink relay UE after the establishment of the sidelink RRC connection.

10. A method for wireless communication that can be performed by a user device ("UE") The steps include receiving a first system information block (SIB) indicating a set of connection timers, The steps include receiving an additional SIB indicating a first set of sidelink connection timers, A step of determining a second set of sidelink connection timers for establishing communication with a network node via a sidelink relay UE, The value of each timer in the second set of sidelink connection timers is determined at least in part on the first set of sidelink connection timers and an additional time offset, the additional time offset is signaled within the first SIB, step, To manage the establishment of communication with the network node via the side link relay UE, the steps include using each connection timer and Methods that include...

11. The method according to claim 10, wherein the establishment of the managed communication includes one of a Radio Resource Control ("RRC") connection establishment procedure, an RRC connection reactivation procedure, or an RRC connection re-establishment procedure.

12. The method according to claim 10, further comprising the step of starting the respective connection timer in response to the transmission of a Wireless Resource Control ("RRC") connection request, an RRC restart request, or an RRC connection re-establishment request.

13. The method according to claim 10, wherein each of the values ​​of the second set of sidelink connection timers is determined based on the set of connection timers from the first SIB, and the second set of sidelink connection timers for establishing communication includes timers "T300", "T301", and "T319".

14. The method of claim 10, further comprising the step of determining the respective values ​​of the second set of sidelink connection timers by using the corresponding timer values ​​of the first set of sidelink connection timers if the first set of sidelink connection timers is included in the additional SIB, and otherwise using the timer values ​​of the equivalent Uu connection timers from the first SIB.

15. A network device for wireless communication, Memory and The memory includes a processor coupled to the memory, and the processor is connected to the network device. To indicate a set of connection timers and to transmit a first system information block (SIB) including an additional time offset, and It is configured to cause the transmission of an additional SIB indicating a first set of sidelink connection timers to be used in combination with the aforementioned additional time offset, Network device.

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