Radio resource control connection procedure for remote wireless devices

Abstract

The invention relates to a radio resource control connection procedure for a remote wireless device. A method includes: receiving, by a relay wireless device: respective radio resource control (RRC) connection requests from a plurality of remote wireless devices; and relaying an RRC message between the cellular base station and each of the plurality of remote wireless devices to establish an RRC connection with the cellular base station, the RRC message comprising a respective RRC setup completion message, each RRC setup completion message is relayed on a Uu link between the relay wireless device and the cellular base station between a respective one of the plurality of remote wireless devices and the cellular base station, and transmitted on the Uu link together with a respective remote wireless device identifier in order to differentiate respective RRC setup completion messages for different remote wireless devices.

Description

[0001] This application is a divisional application of the invention patent application with the application date of August 13, 2019, application number 201910746189.1, and name “Radio Resource Control Connection Process of Remote Wireless Device”. Technical Field

[0002] The present patent application relates to wireless communications, including a radio resource control connection process involving a remote wireless device in a wireless communication system. Background Art

[0003] The use of wireless communication systems is growing rapidly. In addition, wireless communication technology has evolved from only voice communication to also include the transmission of data (such as the Internet and multimedia content).

[0004] Mobile electronic devices may take the form of smart phones or tablet computers that are commonly carried by users. Wearable devices (also known as accessory devices) are a newer form of mobile electronic devices, an example of which is a smart watch. In addition, low-cost, low-complexity wireless devices intended for static or dynamic deployment are also increasing rapidly as part of the development of the "Internet of Things". In other words, the complexity, capabilities, traffic patterns and other characteristics of the required devices are increasingly wide-ranging. In general, it should be expected to recognize and provide improved support for a wide range of required wireless communication characteristics. Therefore, improvements in the art are expected. Summary of the invention

[0005] Embodiments of systems, apparatus, and methods are presented herein for, among other things, performing a radio resource control connection procedure for a remote wireless device in a wireless communication system.

[0006] As described above, there are an increasing number of use cases for different kinds of wireless devices with widely varying capabilities and usage expectations. One direction of expansion of possible use cases supported by wireless communication technologies may include moving toward low-cost and / or low-power wireless devices. The ability to support such wireless devices to establish a radio resource control connection and obtain access to a cellular network through an intermediate relay wireless device may increase the usefulness of such low-cost and / or low-power wireless devices.

[0007] Thus, the techniques described herein include techniques for a remote wireless device providing a relay wireless device with RRC messages that are relayed to a cellular base station; a cellular base station providing a relay wireless device with RRC messages that are relayed to a remote wireless device; and a relay wireless device relaying such messages between a cellular base station and a remote wireless device.

[0008] In addition, the technology described in this article includes technology for detecting link failure and link failure processing in conjunction with a remote radio resource control connection. The technology of detecting link failure and link failure processing is used for a wireless link between a remote wireless device and a relay wireless device, and also for a wireless link between a relay wireless device and a cellular base station.

[0009] The techniques described herein may be implemented in and / or used with a number of different types of devices, including, but not limited to, any of cellular telephones, tablet computers, attached and / or wearable computing devices, portable media players, cellular base stations and other cellular network infrastructure devices, servers, and a variety of other computing devices.

[0010] This summary is intended to provide a brief overview of some of the topics described in this document. Therefore, it should be understood that the above features are only examples and should not be interpreted as narrowing the scope or essence of the subject matter described herein in any way. Other features, aspects and advantages of the subject matter described herein will become apparent through the following detailed description, drawings and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] A better understanding of the present subject matter may be obtained when the following detailed description of the embodiments is considered in conjunction with the following drawings.

[0012] Figure 1 An exemplary wireless communication system including an accessory device according to some embodiments is shown;

[0013] Figure 2 An exemplary wireless communication system is shown in which two wireless devices can perform direct device-to-device communication according to some embodiments;

[0014] Figure 3 is a block diagram illustrating an exemplary wireless device according to some embodiments;

[0015] Figure 4 is a block diagram illustrating an exemplary base station according to some embodiments;

[0016] Figure 5 is a communication flow diagram illustrating an exemplary method for performing presence discovery in a wireless communication system according to some embodiments;

[0017] Figure 6 illustrates aspects of possible wireless communication relay between a remote UE, a relay UE, and a gNB according to some embodiments;

[0018] Figures 7 and 8illustrates exemplary aspects of a possible protocol stack architecture for user plane and control plane communications in a 3GPP based UE to network relay framework according to some embodiments;

[0019] Fig. 9 is a signal flow diagram illustrating various aspects of an exemplary scenario according to some embodiments, in which multiple remote UEs attempt to establish an RRC connection with a gNB via the same relay UE;

[0020] Fig.10 is a signal flow diagram illustrating aspects of an exemplary scenario according to some embodiments, in which a single remote UE attempts to establish an RRC connection with a gNB via a relay UE;

[0021] Fig.11 is a signal flow diagram illustrating aspects of an exemplary scenario according to some embodiments, in which a single remote UE attempts to re-establish an RRC connection with a gNB via a relay UE;

[0022] Fig.12 is a signal flow diagram illustrating aspects of an exemplary scenario in which a single remote UE attempts to resume an RRC connection with a gNB via a relay UE, according to some embodiments;

[0023] Fig.13 is a signal flow diagram illustrating aspects of an exemplary scenario according to some embodiments, in which a gNB releases a remote RRC connection with a remote UE via a relay UE;

[0024] Fig.14 is a signal flow diagram illustrating aspects of an exemplary scenario according to some embodiments, wherein a gNB reconfigures a remote RRC connection with a remote UE via a relay UE;

[0025] Fig.15 is a signal flow diagram illustrating aspects of an exemplary scenario according to some embodiments, wherein remote RRC connection establishment fails due to a link failure between a relay UE and a gNB;

[0026] Fig.16 is a signal flow diagram illustrating aspects of an exemplary scenario according to some embodiments, wherein remote RRC connection re-establishment fails due to a link failure between a relay UE and a gNB;

[0027] Fig.17 is a signal flow diagram illustrating aspects of an exemplary scenario according to some embodiments, wherein a remote RRC connection recovery failure occurs due to a link failure between a relay UE and a gNB;

[0028] Fig.18is a signal flow diagram illustrating aspects of an exemplary scenario according to some embodiments, wherein a response validity timer is used by a relay UE to detect a link failure between a relay UE and a remote UE;

[0029] Fig.19 is a signal flow diagram illustrating aspects of an exemplary scenario according to some embodiments, wherein a response validity timer is used by a relay UE to detect a PC5 interface failure between a relay UE and a remote UE;

[0030] Fig. 20 is a signal flow diagram illustrating aspects of an exemplary scenario according to some embodiments, wherein a response protection timer is used by a remote UE for a link failure between a remote UE and a relay UE;

[0031] Fig.21 is a signal flow diagram illustrating aspects of an exemplary scenario according to some embodiments, wherein a remote RRC connection establishment fails due to a link failure between a relay UE and a remote UE;

[0032] Fig. 22 is a signal flow diagram illustrating aspects of an exemplary scenario according to some embodiments, wherein a remote RRC connection re-establishment fails due to a link failure between a relay UE and a remote UE; and

[0033] Fig.23 is a signal flow diagram illustrating aspects of an exemplary scenario according to some embodiments, wherein a remote RRC connection recovery failure occurs due to a link failure between a relay UE and a remote UE.

[0034] Although the features described herein are susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and are described in detail herein. However, it should be understood that the drawings and detailed description thereof are not intended to limit this document to the specific forms disclosed, but on the contrary, the purpose is to cover all modifications, equivalents and alternatives that fall within the spirit and scope of the subject matter as defined by the appended claims. DETAILED DESCRIPTION

[0035] Acronyms

[0036] The following acronyms are used in this disclosure.

[0037] 3GPP: Third Generation Partnership Project

[0038] 3GPP2: Third Generation Partnership Project 2

[0039] GSM: Global System for Mobile Communications

[0040] UMTS: Universal Mobile Telecommunications System

[0041] LTE: Long Term Evolution

[0042] IoT: Internet of Things

[0043] NB: Narrow Band

[0044] D2D: Device to Device

[0045] OOC: Out of Coverage

[0046] the term

[0047] The following are definitions of terms used in this disclosure:

[0048] Memory medium - any of various types of non-transitory memory devices or storage devices. The term "memory medium" is intended to include installation media, such as CD-ROM, floppy disk or tape devices; computer system memory or random access memory such as DRAM, DDR RAM, SRAM, EDO RAM, Rambus RAM, etc.; non-volatile memory such as flash memory, magnetic media, for example, hard disk drive or optical storage device; registers or other similar types of memory elements, etc. The memory medium may also include other types of non-transitory memory or combinations thereof. In addition, the memory medium may be located in the first computer system executing the program, or may be located in a different second computer system connected to the first computer system via a network such as the Internet. In the latter case, the second computer system may provide program instructions to the first computer for execution. The term "memory medium" may include two or more memory media that may reside in different locations in different computer systems connected, for example, via a network. The memory medium may store program instructions (e.g., expressed as a computer program) that may be executed by one or more processors.

[0049] Carrier Medium—storage media as described above, and physical transmission media such as a bus, network, and / or other physical transmission media that transport signals such as electrical, electromagnetic or digital signals.

[0050] Programmable hardware element - includes various hardware devices that include multiple programmable function blocks connected via programmable interconnects. Examples include FPGA (field programmable gate array), PLD (programmable logic device), FPOA (field programmable object array), and CPLD (complex PLD). Programmable function blocks can vary from fine-grained (combinational logic unit or lookup table) to coarse-grained (arithmetic logic unit or processor core). Programmable hardware elements may also be referred to as "configurable logic units".

[0051] Computer System - Any of various types of computing or processing systems, including a personal computer system (PC), a mainframe computer system, a workstation, a network appliance, an Internet appliance, a personal digital assistant (PDA), a television system, a grid computing system, or other devices or combinations of devices. In general, the term "computer system" can be broadly defined to encompass any device (or combination of devices) having at least one processor that executes instructions from a memory medium.

[0052] User Equipment (UE) (or "UE device") - any of various types of computer systems or devices that are mobile or portable and that perform wireless communications. Examples of UE devices include mobile phones or smartphones (e.g., iPhones). TM , based on Android TM phones), tablets (e.g., iPad TM 、Samsung Galaxy TM ), portable gaming devices (e.g., Nintendo DS TM , PlayStation Portable TM 、Gameboy Advance TM , iPhone TM ), laptops, wearable devices (e.g., smart watches, smart glasses), PDAs, portable Internet devices, music players, data storage devices or other handheld devices, etc. In general, the term "UE" or "UE device" can be broadly defined to include any electronic device, computing device and / or telecommunication device (or combination of devices) that is convenient for a user to transport and capable of wireless communication.

[0053] Wireless Device – Any of various types of computer systems or devices that perform wireless communications. A wireless device may be portable (or mobile), or may be fixed or fixed at a location. A UE is an example of a wireless device.

[0054] Communication device – Any of various types of computer systems or devices that perform communication, which may be wired or wireless. A communication device may be portable (or mobile), or may be fixed or fixed at a location. A wireless device is one example of a communication device. A UE is another example of a communication device.

[0055] Base Station - The term "base station" has the full breadth of its ordinary meaning and includes at least a wireless communication station that is installed at a fixed location and used to communicate as part of a wireless communication system.

[0056] Link budget limited—includes the full scope of its ordinary meaning and includes at least the characteristics of a wireless device (e.g., UE) that exhibits limited communication capabilities or limited power relative to a device that is not link budget limited or relative to a device for which a radio access technology (RAT) standard has been developed. A link budget limited wireless device may experience relatively limited receive capabilities and / or transmit capabilities, which may be due to one or more factors, such as device design, device size, battery size, antenna size or design, transmit power, receive power, current transmission medium conditions, and / or other factors. Such devices may be referred to herein as "link budget limited" (or "link budget constrained") devices. A device may be inherently link budget limited due to the size of the device, battery power, and / or transmit / receive power. For example, a smart watch that communicates with a base station via LTE or LTE-A may be inherently link budget limited due to its reduced transmit / receive power and / or antenna reduction. Wearable devices such as smart watches are generally link budget limited devices. Alternatively, a device may not be inherently link budget limited, e.g., may have sufficient size, battery power, and / or transmit / receive power for normal communication over LTE or LTE-A, but may be temporarily link budget limited due to current communication conditions, e.g., a smartphone at a cell edge, etc. It should be noted that the term "link budget limited" includes or encompasses power limitations, and thus a link-limited device may be considered a link budget limited device.

[0057] Processing element (or processor) - refers to various elements or combinations of elements that are capable of performing functions in a device, such as a user equipment device or a cellular network device. A processing element may include, for example, a processor and associated memory, portions or circuits of individual processor cores, entire processor cores, separate processors, processor arrays, circuits such as ASICs (application specific integrated circuits), programmable hardware elements such as field programmable gate arrays (FPGAs), and any of the above combinations.

[0058] Automatic—refers to an action or operation performed by a computer system (e.g., software executed by a computer system) or a device (e.g., a circuit system, a programmable hardware element, an ASIC, etc.) without the need for user input to directly specify or perform the action or operation. Thus, the term "automatic" is in contrast to a user manually performing or specifying an action, where the user provides input to directly perform the action. An automatic process may be initiated by input provided by a user, but subsequent actions performed "automatically" are not specified by the user, i.e., are not performed "manually," where the user specifies each action to be performed. For example, a user filling out an electronic form by selecting each field and providing input specifying information (e.g., by typing in information, selecting check boxes, radio selections, etc.) is manually filling out the form, even though the computer system must update the form in response to the user action. The form may be automatically filled out by a computer system, where the computer system (e.g., software executed on the computer system) analyzes the fields of the form and fills out the form without any user input specifying the answers to the fields. As indicated above, a user may invoke automatic filling out of a form, but not participate in the actual filling out of the form (e.g., the user does not manually specify the answers to the fields but rather they are automatically completed). This specification provides various examples of operations that are automatically performed in response to actions taken by a user.

[0059] Configured to - Various components may be described as being "configured to" perform one or more tasks. In such environments, "configured to" is a broad statement that generally means "having a structure" that performs one or more tasks during operation. Thus, a component can be configured to perform a task even when the component is not currently performing the task (e.g., a set of electrical conductors can be configured to electrically connect a module to another module even when the two modules are not connected). In some environments, "configured to" can be a broad statement that generally means "having a circuit system" that performs one or more tasks during operation. Thus, the component can be configured to perform a task even when the component is not currently turned on. Typically, the circuit system that forms the structure corresponding to "configured to" may include hardware circuits.

[0060] For ease of description, various components may be described as performing one or more tasks. Such descriptions should be interpreted as including the phrase "configured to". The description of a component being configured to perform one or more tasks is expressly intended not to invoke the interpretation of the sixth paragraph of 35 U.S.C. §112 for that component.

[0061] Figure 1-Figure 2 :Wireless communication system

[0062] Figure 1 An example of a wireless cellular communication system is illustrated. It should be noted that Figure 1This represents one possibility among many, and the features of the present disclosure may be implemented by any of a variety of systems as desired.For example, the embodiments described herein may be implemented in any type of wireless device.

[0063] As shown, the exemplary wireless communication system includes a cellular base station 102 that communicates over a transmission medium with one or more wireless devices 106A, 106B, etc. and an accessory device 107. Wireless devices 106A, 106B, and 107 may be user equipment, which may be referred to herein as "user equipment" (UE) or UE devices.

[0064] Base station 102 may be a base transceiver station (BTS) or a cell site and may include hardware and / or software that implements wireless communication with UE devices 106A, 106B, and 107. If base station 102 is implemented in the context of LTE, it may be referred to as an "eNodeB" or "eNB". If base station 102 is implemented in the context of 5G NR, it may alternatively be referred to as a "gNodeB" or "gNB". Base station 102 may also be equipped to communicate with network 100 (e.g., a core network of a cellular service provider, a telecommunications network such as a public switched telephone network (PSTN) and / or the Internet, as well as various possibilities). Thus, base station 102 may facilitate communication between UE devices 106 and 107 and / or communication between UE devices 106 / 107 and network 100. Also as used herein, with respect to a UE, sometimes a base station may be considered to represent a network in consideration of uplink and downlink communications of the UE. Therefore, a UE that communicates with one or more base stations in a network may also be interpreted as a UE that communicates with a network.

[0065] In other embodiments, the base station 102 may be configured to provide communications via one or more other wireless technologies, such as an access point supporting one or more WLAN protocols, such as 802.11a, b, g, n, ac, ad and / or ax, or LTE in an unlicensed band (LAA).

[0066] The communication area (or coverage area) of the base station 102 may be referred to as a “cell.” The base station 102 and the UE 106 / 107 may be configured to communicate over a transmission medium using any of various radio access technologies (RATs) or wireless communication technologies, such as GSM, UMTS (WCDMA, TDS-CDMA), LTE, Advanced LTE (LTE-A), NR, HSPA, 3GPP2 CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD), Wi-Fi, etc.

[0067] Thus, base station 102 and other similar base stations (not shown) operating according to one or more cellular communication technologies can be provided as a cell network that can provide continuous or near-continuous overlapping service to UE devices 106A-N and 107 and similar devices within a geographic area via one or more cellular communication technologies.

[0068] Note that, at least in some cases, UE devices 106 / 107 may be able to communicate using any of a variety of wireless communication technologies. For example, UE devices 106 / 107 may be configured to communicate using one or more of GSM, UMTS, CDMA2000, LTE, LTE-A, NR, WLAN, Bluetooth, one or more global navigation satellite systems (GNSS, such as GPS or GLONASS), one and / or more mobile television broadcast standards (e.g., ATSC-M / H), etc. Other combinations of wireless communication technologies (including more than two wireless communication technologies) are also possible. Similarly, in some cases, UE devices 106 / 107 may be configured to communicate using only a single wireless communication technology.

[0069] UE 106A and 106B may include handheld devices such as smart phones or tablets, and / or may include any of various types of devices with cellular communication capabilities. For example, one or more of UE 106A and 106B may be wireless devices intended for static or dynamic deployment, such as home appliances, measurement devices, control devices, etc. UE 106B may be configured to communicate with UE device 107, which may be referred to as accessory device 107. Accessory device 107 may be any of various types of wireless devices, which may generally be wearable devices with a small form factor and limited battery, output power, and / or communication capabilities relative to UE 106. As a common example, UE 106B may be a smart phone carried by a user, and accessory device 107 may be a smart watch worn by the same user. UE 106B and accessory device 107 may communicate using any of various short-range communication protocols, such as Bluetooth or Wi-Fi. In some cases, UE 106B and accessory device 107 can perform direct peer-to-peer communications using proximity services (ProSe) technology (e.g., in a manner supported by a cellular base station). For example, such ProSe communications can be performed as part of a relay link to support a radio resource control connection between accessory device 107 and BS 102, such as according to various embodiments described herein.

[0070] UE 106B may also be configured to communicate with UE 106A. For example, UE 106A and UE 106B may be able to perform direct device-to-device (D2D) communications. D2D communications may be supported by cellular base station 102 (e.g., BS 102 may facilitate discovery, as well as various possible forms of assistance), or may be performed in a manner that is not supported by BS 102. For example, it may be the case that UE 106A and UE 106B are able to arrange and perform D2D communications (e.g., including discovery communications) even when BS 102 and other cellular base stations have no coverage.

[0071] Figure 2 An exemplary BS 102 is shown communicating with a UE device 106, which in turn communicates with an accessory device 107. The UE device 106 and the accessory device 107 may be a mobile phone, a tablet or any other type of handheld device, a smart watch or other wearable device, a media player, a computer, a laptop, or virtually any type of wireless device. In some embodiments, the accessory device may be a wireless device designed to have low cost and / or low power consumption, and may benefit from a relay link with the UE device 106 (and / or another companion device) to support communications with the BS 102. For example, in Figure 2 In the exemplary scenario of , a device that utilizes a relay link with another wireless device to communicate with a cellular base station may also be referred to herein as a remote wireless device, a remote device, or a remote UE apparatus, and a wireless device that provides such a relay link may also be referred to herein as a relay wireless device, a relay device, or a relay UE device. According to some embodiments, such BS 102, UE 106, and accessory device 107 may be configured to perform radio resource control procedures for the remote wireless device according to the various techniques described herein.

[0072] Both UE 106 and accessory device 107 may include a device or integrated circuit called a cellular modem for facilitating cellular communications. The cellular modem may include one or more processors (processing elements) configured to execute program instructions stored in a memory and / or various hardware components described herein. UE 106 and / or accessory device 107 may each execute any of the method implementation schemes described herein by executing such stored instructions. Alternatively or in addition, UE 106 and / or accessory device 107 may also include programmable hardware elements, such as FPGAs (field programmable gate arrays), integrated circuits, and / or any of various other possible hardware components configured to execute (e.g., individually or in combination) any of the method implementation schemes described herein or any of any of the method implementation schemes described herein. The cellular modem described herein may be used in a UE device as defined herein, a wireless device as defined herein, or a communication device as defined herein. The cellular modem described herein may also be used in a base station or other similar network side device.

[0073] UE 106 and / or accessory device 107 may include one or more antennas for communicating according to one or more RAT standards using one or more wireless communication protocols. In some embodiments, one or both of UE 106 or accessory device 107 may be configured to communicate using a single shared radio component. The shared radio component may be coupled to a single antenna, or may be coupled to multiple antennas (e.g., for MIMO) for performing wireless communications. Typically, the radio component may include any combination of a baseband processor, an analog RF signal processing circuit system (e.g., including filters, mixers, oscillators, amplifiers, etc.), or a digital processing circuit system (e.g., for digital modulation and other digital processing). Similarly, the radio component may use the aforementioned hardware to implement one or more receive chains and transmit chains.

[0074] Alternatively, UE 106 and / or accessory device 107 may include two or more radio components. For example, in some embodiments, UE 106 or accessory device 107 may include a separate transmit chain and / or receive chain (e.g., including separate antennas and other radio components) for each wireless communication protocol with which it is configured to communicate. As another possibility, UE 106 and / or accessory device 107 may include one or more radio components shared between multiple wireless communication protocols, and one or more radio components used uniquely by a single wireless communication protocol. For example, UE 106 and / or accessory device 107 may include a shared radio component for communicating using any of LTE or CDMA2000 1xRTT (or LTE or NR, or LTE or GSM), and a shared radio component for communicating using Wi-Fi and BLUETOOTH. TM Each of the independent radio components for communication. Other configurations are also possible.

[0075] Figure 3 :Block diagram of UE device

[0076] Figure 3 One possible block diagram of a UE device, such as UE device 106 or 107, is shown. As shown, UE device 106 / 107 may include a system on chip (SOC) 300, which may include parts for various purposes. For example, as shown, SOC 300 may include: a processor 302, which may execute program instructions for UE device 106 / 107; and a display circuit system 304, which may perform graphics processing and provide display signals to display 360. SOC 300 may also include motion sensing circuit system 370, which may detect motion of UE 106, for example, using any of a gyroscope, accelerometer, and / or various other motion sensing components. Processor 302 may also be coupled to a memory management unit (MMU) 340, which may be configured to receive addresses from processor 302 and translate those addresses into locations in memory (e.g., memory 306, read-only memory (ROM) 350, flash memory 310) and / or other circuits or devices, such as display circuitry 304, radio 330, I / F 320, and / or display 360. MMU 340 may be configured to perform memory protection and page table translation or setup. In some embodiments, MMU 340 may be included as part of processor 302.

[0077] As shown, SOC 300 may be coupled to various other circuits of UE 106 / 107. For example, UE 106 / 107 may include various types of memory (e.g., including NAND flash memory 310), connector interface 320 (e.g., for coupling to a computer system, docking station, charging station, etc.), display 360, and wireless communication circuit system 330 (e.g., for LTE, LTE-A, NR, CDMA2000, Bluetooth, Wi-Fi, NFC, GPS, etc.).

[0078] The UE device 106 / 107 may include at least one antenna and may include multiple antennas 335a and 335b for performing wireless communications with a base station and / or other devices in some embodiments. For example, the UE device 106 / 107 may use antennas 335a and 335b to perform wireless communications. As described above, the UE device 106 / 107 may be configured to use multiple wireless communication standards or radio access technologies (RATs) for wireless communications in some embodiments.

[0079] The wireless communication circuit system 330 may include a Wi-Fi logic component 332, a cellular modem 334, and a Bluetooth logic component 336. The Wi-Fi logic component 332 is used to enable the UE device 106 / 107 to perform Wi-Fi communications on an 802.11 network. The Bluetooth logic component 336 is used to enable the UE device 106 / 107 to perform Bluetooth communications. The cellular modem 334 may be a lower power cellular modem capable of performing cellular communications according to one or more cellular communication technologies.

[0080] As described herein, the UE 106 / 107 may include hardware components and software components for implementing embodiments of the present disclosure. The processor 302 of the UE device 106 / 107 may be configured to implement part or all of the methods described herein, for example, by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). In other embodiments, the processor 302 may be configured as a programmable hardware element, such as an FPGA (field programmable gate array) or as an ASIC (application-specific integrated circuit). In addition, the processor 302 may be coupled to a processor such as a processor 106 / 107. Figure 3The other components shown and / or can interoperate with it to perform radio resource control processes for remote wireless devices according to various embodiments disclosed herein. The processor 302 can also implement various other applications and / or end-user applications running on the UE 106. Alternatively or in addition, one or more components of the wireless communication circuit system 330 (e.g., cellular modem 334) of the UE device 106 / 107 can be configured as a processor that executes program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium), is configured as an FPGA (field programmable gate array) and / or uses a processor of a dedicated hardware component that may include an ASIC (application-specific integrated circuit) to implement part or all of the methods described herein.

[0081] Figure 4 :Block diagram of base station

[0082] Figure 4 An exemplary block diagram of a base station 102 according to some embodiments is shown. Note that Figure 4 The base station of is only one example of a possible base station. As shown, the base station 102 may include a processor 404 that may execute program instructions for the base station 102. The processor 404 may also be coupled to a memory management unit (MMU) 440 (which may be configured to receive addresses from the processor 404 and convert these addresses to locations in memory (e.g., memory 460 and read-only memory (ROM) 450)) or to other circuits or devices.

[0083] The base station 102 may include at least one network port 470. Figure 1 and Figure 2 As described in , the network port 470 may be configured to couple to a telephone network and provide multiple devices, such as the UE devices 106 / 107 , with access to the telephone network.

[0084] The network port 470 (or an additional network port) may be further configured or alternatively configured to be coupled to a cellular network, such as a core network of a cellular service provider. The core network may provide mobility-related services and / or other services to multiple devices such as UE devices 106 / 107. For example, the core network may include, for example, a mobility management entity (MME) for providing mobility management services, a serving gateway (SGW) and / or a packet data network gateway (PGW) for providing external data connections such as to the Internet, and the like. In some cases, the network port 470 may be coupled to a telephone network via the core network, and / or the core network may provide a telephone network (e.g., between other UE devices served by the cellular service provider).

[0085] The base station 102 may include at least one antenna 434 and possibly multiple antennas. One or more antennas 434 may be configured to operate as a wireless transceiver and may be further configured to communicate with the UE device 106 / 107 via the radio component 430. One or more antennas 434 communicate with the radio component 430 via a communication chain 432. The communication chain 432 may be a receive chain, a transmit chain, or both. The radio component 430 may be configured to communicate via various wireless communication standards, including but not limited to LTE, LTE-A, NR, GSM, UMTS, CDMA2000, Wi-Fi, etc.

[0086] Base station 102 may be configured to communicate wirelessly using multiple wireless communication standards. In some cases, base station 102 may include multiple radio components that enable base station 102 to communicate according to multiple wireless communication technologies. For example, as one possibility, base station 102 may include an LTE radio component for performing communication according to LTE and a Wi-Fi radio component for performing communication according to Wi-Fi. In such a case, base station 102 may be able to operate as both an LTE base station and a Wi-Fi access point. As another possibility, base station 102 may include a multi-mode radio component that can perform communication according to any of multiple wireless communication technologies (e.g., LTE and NR, LTE and Wi-Fi, LTE and UMTS, LTE and CDMA2000, UMTS and GSM, etc.).

[0087] As further described later herein, BS 102 may include hardware and software components for implementing or supporting implementations of the features described herein. According to some embodiments, the processor 404 of the base station 102 may be configured to implement part or all of the methods described herein, for example, by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). Alternatively, the processor 404 may be configured as a programmable hardware element such as an FPGA (field programmable gate array), or as an ASIC (application-specific integrated circuit) or a combination thereof. Alternatively (or in addition), in combination with one or more of the other components 430, 432, 434, 440, 450, 460, 470, the processor 404 of the BS 102 may be configured to implement or support implementation of a radio resource control process for a remote wireless device according to various embodiments disclosed herein and / or various other features described herein.

[0088] Figure 5 :Communication flow chart

[0089] Figure 5is a communication flow diagram illustrating a method for performing a radio resource control procedure for a remote wireless device in a wireless communication system according to some embodiments. In various embodiments, some of the method elements shown may be performed simultaneously in an order different from the order shown, may be replaced by other method elements, or may be omitted. Additional method elements may also be performed as needed.

[0090] Figure 5 Aspects of the method may be performed by a wireless device and / or a cellular base station, such as in Figures 1 to 4 shown in and relative to Figures 1 to 4 The UE 106A-B and / or BS 102 described herein may be implemented, or more generally, may be implemented in other devices in combination with any of the computer systems or devices shown in the above figures as needed. Note that although the communication technology and / or features associated with LTE, NR and / or 3GPP specification documents are described in a manner involving the use of the communication technology and / or features associated with LTE, NR and / or 3GPP specification documents, Figure 5 At least some elements of the method, but this description is not intended to limit the present disclosure and can be used in any suitable wireless communication system as needed Figure 5 Aspects of the method. As shown, the method may operate as follows.

[0091] In 502, a wireless device ("first wireless device" or "remote wireless device") 107 may perform a radio resource control (RRC) procedure with a cellular base station 102 via another wireless device ("second wireless device" or "relay wireless device") 106. The remote wireless device may be any of various types of wireless devices capable of indirectly performing wireless communications with a cellular base station via an intermediate relay wireless device. As one possibility, the remote wireless device may be an accessory device, such as a smart watch or other wearable device configured as a low-cost and / or low-power wireless device. The relay wireless device may be any of various types of wireless devices capable of supporting wireless communications between the remote wireless device and the cellular base station by acting as an intermediate relay wireless device. As one possibility, the relay wireless device may be a smartphone capable of acting as a companion device to the remote wireless device. Many other types of wireless devices may also function as remote wireless devices and / or relay wireless devices. The cellular base station may be any of various types of base stations capable of indirectly performing wireless communications with the remote wireless device via an intermediate relay wireless device and capable of providing access to a cellular network. As one possibility, the cellular base station may be a 3GPP 5G NR gNB. Alternatively (or in addition), the cellular base station may be capable of operating in accordance with any of a variety of other possible cellular communication standards.

[0092] The RRC procedure may include any of a variety of RRC procedures. According to at least some embodiments, the RRC procedure may be used to attempt to establish an RRC connection between the remote wireless device and the cellular base station. For example, the remote wireless device may attempt to perform an RRC connection procedure, an RRC reestablishment procedure, or an RRC recovery procedure. As another possibility, the RRC procedure may be used to reconfigure an existing RRC connection between the remote wireless device and the cellular base station (e.g., the cellular base station may attempt to perform an RRC reconfiguration procedure), or may be used to release an existing RRC connection between the remote wireless device and the cellular base station (e.g., the cellular base station may attempt to perform an RRC release procedure).

[0093] To perform the RRC procedure, the relay wireless device may relay RRC messages between the remote wireless device and the cellular base station. For example, to perform the RRC connection procedure, the remote wireless device may transmit an RRC connection request to the relay wireless device, which may then transmit the RRC connection request to the cellular base station on behalf of the remote wireless device. The cellular base station may transmit an RRC setup message configured to facilitate the RRC connection setup with the remote wireless device to the relay wireless device in response to the RRC connection request. The relay wireless device may then transmit an RRC setup message to the remote wireless device on behalf of the cellular base station, for example including configuration information for establishing the RRC connection. The remote wireless device may also transmit an RRC setup completion message to the relay wireless device, which may then transmit an RRC setup completion message to the cellular base station on behalf of the remote wireless device.

[0094] Note that the RRC messages relayed by the relay wireless device between the remote wireless device and the cellular base station may be different for different RRC procedures. According to some embodiments, some or all of the RRC messages may be completely relayed by the relay wireless device. As another possibility, some or all of the RRC message content may not be relayed, and / or additional information may be added to some or all of the relayed RRC messages. For example, in some cases, the configuration information for establishing a remote RRC connection may include some information used by the relay wireless device to establish one or more relay signaling radio bearers between the relay wireless device and the cellular base station, and the remote wireless device may not need this information to establish the remote RRC connection.

[0095] As another possibility, when providing an RRC message to a cellular base station on behalf of a remote wireless device, the relay wireless device may provide identification information associated with the remote wireless device to the cellular base station, e.g., to indicate to the cellular base station that the RRC message is provided on behalf of the remote wireless device, and similarly, when providing an RRC message to a relay wireless device on behalf of the remote wireless device, the cellular base station may provide identification information associated with the remote wireless device to the relay wireless device, e.g., to indicate to the relay wireless device that the RRC message is being provided on behalf of the remote wireless device. In some cases, providing such identification information may be used to distinguish between RRC messages related to an RRC connection between the relay wireless device and the cellular base station and RRC messages related to an RRC connection between the remote wireless device and the cellular base station. This distinction may also be possible by using a different signaling radio bearer for the relay RRC messages than for the RRC messages related to the RRC connection between the relay wireless device and the cellular base station. If the relay wireless device is configured to relay RRC messages between a cellular base station and each of a plurality of remote wireless devices, providing such identification information may also be used to identify which RRC messages are associated with which RRC connections; for example, in this case, it may be that each RRC message relayed between a cellular base station and a corresponding remote wireless device includes remote wireless device identification information for the corresponding remote wireless device.

[0096] According to at least some embodiments, the relay wireless device may transmit a discovery broadcast message (e.g., based on an event-driven or periodic trigger) indicating that the relay wireless device supports relay RRC messages. The remote wireless device may receive the discovery broadcast message from the relay wireless device (and possibly from one or more other wireless devices that can support relay RRC messages). The remote wireless device may perform link selection to determine a wireless link on which to attempt to establish a relay RRC connection with a cellular base station, and may select the relay wireless device based at least in part on the discovery broadcast message received from the relay wireless device. The remote wireless device may attempt to perform an RRC procedure with the cellular base station via the relay wireless device based at least in part on the link selection.

[0097] Since a remote RRC connection may rely on multiple radio links (e.g., a radio link between a remote wireless device and a relay wireless device, and a radio link between the relay wireless device and a cellular base station), it may be beneficial to provide techniques for handling radio link interruptions. According to some embodiments, one or both of the remote wireless device or the relay wireless device may utilize a response timer to help determine whether a link failure has occurred in the radio link between the remote wireless device and the relay wireless device. For example, the relay wireless device may start a response validity timer based at least in part on relaying a radio resource control message to the remote wireless device, and may stop the response validity timer when a response is received from the remote wireless device. If the response validity timer expires without receiving a response, the relay wireless device may determine that a link failure has occurred in the radio link between the relay wireless device and the remote wireless device. If the relay wireless device determines that a link failure has occurred in the radio link between the relay wireless device and the remote wireless device, for example, in this manner or in any of a variety of other manners, the relay wireless device may provide an indication of a link failure of the radio link between the relay wireless device and the remote wireless device to the cellular base station. In at least some cases, the relay wireless device may receive an indication from the cellular base station to release the remote wireless device in response to an indication of a link failure of a wireless link between the relay wireless device and the remote wireless device.

[0098] In some embodiments, the remote wireless device may start a response guard timer based at least in part on providing a radio resource control message to the relay wireless device, and may stop the response guard timer upon receiving a response to the radio resource control message from the relay wireless device. If the response guard timer expires without receiving a response, the remote wireless device may determine that a link failure has occurred in a wireless link between the remote wireless device and the relay wireless device. In this case, the remote wireless device may perform link selection to determine a wireless link on which to attempt to establish a relayed radio resource control connection with the cellular base station, for example based at least in part on a link failure in a wireless link between the remote wireless device and the relay wireless device.

[0099] According to some embodiments, an acknowledgement may be provided, typically in response to an RRC message transmitted as part of a remote RRC procedure (e.g., the relay signaling radio bearer used may be configured in acknowledged mode or AM). Based on such an acknowledgement (or the lack thereof) and / or in any of a variety of other ways, the relay wireless device may also be able to determine whether a link failure has occurred in the wireless link between the relay wireless device and the cellular base station. If such a link failure is detected, the relay wireless device may provide an indication of a link failure of the wireless link between the relay wireless device and the cellular base station to the remote wireless device. The indication may include any of the following explicit indications: a link failure has occurred in the wireless link between the relay wireless device and the cellular base station, an indication to suspend the wireless link between the relay wireless device and the remote wireless device, or an indication to release the wireless link between the relay wireless device and the remote wireless device. Based on the indication (e.g., if an indication to release the wireless link between the first wireless device and the second wireless device is received), the remote wireless device may perform link selection to re-determine the wireless link on which to attempt to establish a relayed radio resource control connection with the cellular base station. Alternatively (e.g., if an indication is received to suspend the wireless link between the relay wireless device and the remote wireless device), the remote wireless device may wait for up to a certain period of time before performing link selection, for example, if the relay wireless device is able to reestablish the wireless link with the cellular network and resume relaying RRC messages with the cellular network on behalf of the remote wireless device.

[0100] Thus, using the techniques described herein, a remote wireless device may establish and manage an RRC connection with a cellular network via a relay wireless device, and the remote wireless device, the relay wireless device, and the cellular network may handle potential link failures of a wireless link used to support the remote RRC connection. According to at least some embodiments, such techniques may be used to support cellular communications for a wider variety of wireless devices, such as potentially helping to expand the range of possible wireless devices that can further utilize cellular communications to implement low-cost and / or low-power wireless devices.

[0101] Figures 6 to 23 and additional information

[0102] Provided Figures 6 to 23 and the following additional information, which illustrates the Figure 5 Further considerations and possible specific implementation details of the method are not intended to limit the present disclosure as a whole. Various variations and alternatives to the details provided below are possible and should be considered to fall within the scope of the present disclosure.

[0103] 3GPP 5G NR cellular communications technology is being developed for a variety of uses, including enhanced mobile broadband (eMBB), ultra-reliable low latency communications (URLLC), and massive machine type communications (mMTC). mMTC use cases may include widespread deployment of wireless devices designed to have relatively low cost and / or low power consumption. Such devices may include wearable devices, devices, process control devices, measurement devices, and / or any of a variety of other types of devices. In at least some embodiments (e.g., in some cases, wearable devices), it may be the case that such devices may typically be relatively close to another wireless device (e.g., in some cases, a smart phone) that can be used as a relay for communicating with a cellular network. Therefore, in at least some embodiments, it is advantageous to support a UE to NW communication relay framework, for example to help support the operation of low cost and / or low power wireless devices that can benefit from such a framework. For example, Figure 6 Aspects of a possible exemplary wireless communication relay between a remote UE 602, a relay UE 604, and a cellular base station 606 are shown. As shown, in the illustrated scenario, the remote UE 602 can communicate with the cellular base station 606 via a relay link between the remote UE 606 and the relay UE 602 and a Uu link between the relay UE 604 and the cellular base station 604.

[0104] According to various embodiments, there may be multiple possible types of UE to NW relay frameworks. As one possibility, at least in some cases, a layer 3 relay may be used that can be implemented without affecting the access layer communication layer. As another possibility, a layer 2 relay may be used, for example, by establishing and maintaining a radio resource control connection that terminates between a remote UE and a cellular base station. Figures 7 and 8 Exemplary aspects of a possible protocol stack architecture for user plane and control plane communications in a 3GPP based UE to network relay framework, where communication relay is implemented at Layer 2, according to some embodiments are shown.

[0105] More specifically, Figure 7 A user plane radio protocol stack for a layer 2 UE to a network relay is shown, which utilizes a PC5 interface between a remote UE 702 and a relay UE 704 to provide a communication link between the remote UE 702 and an eNB 706, and provides a communication link to a core network 708 to which the eNB 706 provides access. Similarly, Figure 8A control plane radio protocol stack for a Layer 2 UE to network relay is shown, which utilizes a PC5 interface between a remote UE 802 and a relay UE 804 to provide a communication link between the remote UE 802 and an eNB 806, and provides a communication link to a core network 808 that provides access to the eNB 806. As shown, the relay may be performed above the RLC sublayer. The Uu PDCP and RRC links may be terminated between the remote UE and the eNB, while the RLC, MAC and PHY and non-3GPP transport layers are terminated in each link (e.g., the link between the remote UE and the relay UE, and the link between the relay UE and the eNB).

[0106] Currently, an RRC connection procedure may be performed between a UE and a network via a direct connection over a Uu interface, e.g., in accordance with 3GPP-based cellular communications. For an RRC connection procedure between remote UEs, where peer RRC entities are terminated at the remote UE and at the network, RRC message transmissions may be relayed via a relay UE, e.g., such that, in addition to a Uu link between the relay UE and the network, an additional relay link may exist between the relay UE and the remote UE. Since the Uu link and the relay link may be maintained independently, a remote RRC procedure may fail due to interruption of the relay link or the Uu link. Therefore, it may be important to carefully design the RRC procedure framework to support the ability of the remote UE to perform the RRC procedure.

[0107] According to some embodiments, RRC message delivery of a remote UE via a Uu link may be performed via a relay signaling radio bearer (SRB) established between the network and the relay UE. The network may be able to establish one or more relay SRBs. It is possible that all relay SRBs are configured in radio link control (RLC) confirmed mode (AM). In the case of using multiple relay SRBs, different relay SRBs may be used for different types of signaling. For example, as a possibility, relay SRB0 may be used for 3GPP SRB0 transmission, relay SRB1 may be used for 3GPP SRB1 transmission, and relay SRB2 may be used for 3GPP SRB2 transmission. Note that other configurations are also possible. The relay SRB may be common to all remote UEs that have established a relay link with a given relay UE. It is possible that each RRC message of the remote UE is transmitted together with a remote UE identifier, for example, in order to distinguish RRC messages of different remote UEs within one relay SRB.

[0108] As previously described herein, link failure detection may be an important consideration for supporting remote RRC procedures. For bidirectional RRC procedures (e.g., a response is expected for each message of the RRC procedure), the relay UE may be able to utilize a response validity timer to control the RRC response message from the remote UE over the relay link. For example, the relay UE may start a response validity timer when sending an RRC message to the remote UE, and stop the timer when the relay UE receives the expected RRC response from the remote UE. When the timer expires (e.g., if an RRC response is received from the remote UE while the timer is running), the relay UE may determine that the RRC message transmitted via the relay link has failed.

[0109] For each possible RRC process, if the relay UE can detect that an RRC message transmission failure has occurred (e.g., in a relay link or a Uu link), the relay UE can take action in response to the RRC message transmission failure. For example, for a relay link failure situation, the relay UE can notify the network of the relay link failure. For a Uu link failure situation, the relay UE can provide information to the remote UE based on the Uu link failure, which can facilitate the remote UE to perform link reselection. For example, as one possibility, the relay UE can send an indication of the Uu link failure to the remote UE. As another possibility, the relay UE can send an indication to suspend the relay link to all remote UEs that have a relay link established with the relay UE. As another possibility, the relay UE can directly close the relay link with the remote UE (e.g., it may not explicitly indicate that a Uu link failure has occurred).

[0110] Figures 9 to 14 is a signal flow diagram showing further details of various possible Remote RRC procedures. Fig. 9 Various aspects of an exemplary scenario according to some embodiments are shown, in which multiple remote UEs attempt to establish an RRC connection with a gNB via the same relay UE. In the exemplary scenario, RRC message delivery of the remote UEs in the Uu link may be performed over a relay SRB established between the relay UE and the network.

[0111] As shown, in the illustrated scenario, in 910, the relay UE 906 may establish an RRC connection with the gNB 908, potentially including establishing a relay SRB configuration. This may include establishing a network of relay SRB1 for remote UE SRB0 transmissions and relay SRB2 for remote UE SRB1 and SRB2 transmissions. In 912, the first remote UE 902 may provide an RRC connection request to the relay UE 906. In 914, the relay UE 906 may provide a connection request to the gNB 908 on behalf of the first remote UE 902, for example, including identification information for the first remote UE 902. The connection request may be provided using relay SRB1, for example, because it may relay SRB0 transmissions from the first remote UE 902. In 916, the second remote UE 904 may provide an RRC connection request to the relay UE 906. At 918, the relay UE 906 may provide a connection request to the gNB 908 on behalf of the second remote UE 904, e.g., including identification information for the second remote UE 904. The connection request may be provided using relay SRB1, e.g., because it may relay SRB0 transmissions from the first remote UE 902.

[0112] In 920, the gNB 908 may provide an RRC setup message intended for the first remote UE 902 to the relay UE 906. The RRC setup message intended for the first remote UE 902 may include identification information for the first remote UE 902. In 922, the relay UE 906 may provide the RRC setup message to the first remote UE 902 on behalf of the gNB 908. Similarly, in 924, the gNB 908 may provide an RRC setup message intended for the second remote UE 904 to the relay UE 906. The RRC setup message intended for the second remote UE 904 may include identification information for the second remote UE 904. In 926, the relay UE 906 may provide the RRC setup message to the second remote UE 904 on behalf of the gNB 908. Note that for both RRC setup messages provided by the gNB 908, the relay SRB1 may be used again.

[0113] At 928, the first remote UE 902 may provide an RRC setup complete message to the relay UE 906. At 930, the relay UE 906 may provide an RRC setup complete message to the gNB 908 on behalf of the first remote UE 902, e.g., including identification information for the first remote UE 902. The RRC setup complete message may be provided using relay SRB2, e.g., because it may relay SRB1 transmissions from the first remote UE 902. At 932, the second remote UE 904 may provide an RRC setup complete message to the relay UE 906. At 934, the relay UE 906 may provide an RRC setup complete message to the gNB 908 on behalf of the second remote UE 904, e.g., including identification information for the second remote UE 904. The RRC setup complete message may be provided using relay SRB2, e.g., because it may relay SRB1 transmissions from the second remote UE 904. Note that different types of remote UE identification information may be used for different SRBs. For example, for SRB0 transmission, the remote UE identification information may be allocated by the relay UE, while for SRB1 transmission, the remote UE identification may include full or partial cell radio network temporary identifier (C RNTI) information.

[0114] Fig.10Aspects of an exemplary scenario according to some embodiments are shown, in which a single remote UE attempts to establish an RRC connection with a gNB via a relay UE. As shown, in the illustrated scenario, at 1008, remote UE 1002 may provide an RRC connection request to relay UE 1004. At 1010, remote UE 1002 and relay UE 1004 may be connected. At 1012, relay UE 1004 may provide an RRC connection request to gNB 1006 using a relay SRB and indicate identification information of remote UE 1002. At 1014, gNB 1006 may provide an RRC connection establishment message to relay UE 1004 using the relay SRB. The RRC connection setup message may include C RNTI information of the remote UE 1002, as well as relay link configuration information, bearer configuration information, Uu data radio bearer configuration information, mapping configuration information, and / or any of various information that supports establishing a remote RRC connection between the gNB 1006 and the remote UE 1002. In 1016, the relay UE 1004 may provide the RRC connection setup message to the remote UE 1002, including at least some of the information received from the gNB 1006, such as any information required by the remote UE 1002 as part of establishing a remote RRC connection between the gNB 1006 and the remote UE 1002 (e.g., relay link configuration information, bearer configuration information). In 1018, the remote UE 1002 may connect with the gNB 1006. In 1020, remote UE 1002 may complete the RRC connection establishment with gNB 1006 by providing an RRC setup complete message to relay UE 1004, and in 1022, relay UE 1004 may provide an RRC setup complete message to gNB 1006 using a relay SRB and indicate identification information of remote UE 1002. In 1024, gNB 1006 may also connect with remote UE 1002.

[0115] Fig.11Aspects of an exemplary scenario according to some embodiments are shown, in which a single remote UE attempts to reestablish an RRC connection with a gNB via a relay UE. As shown, in the illustrated scenario, in 1108, remote UE 1102 and relay UE 1104 may be connected. In 1110, remote UE 1102 may provide an RRC reestablishment request to relay UE 1104. In 1112, relay UE 1104 may provide an RRC reestablishment request to gNB 1106 using a relay SRB and indicate identification information of remote UE 1102. In 1114, gNB 1106 may provide an RRC reestablishment message to relay UE 1104 using the relay SRB. The RRC re-establishment message may include CRNTI information of the remote UE 1102, as well as relay link configuration information, bearer configuration information, Uu data radio bearer configuration information, mapping configuration information, and / or any of various information that supports re-establishing a remote RRC connection between the gNB 1106 and the remote UE 1102. In 1116, the relay UE 1004 may provide the RRC re-establishment message to the remote UE 1102, including at least some of the information received from the gNB 1106, such as any information required by the remote UE 1102 as part of re-establishing the remote RRC connection between the gNB 1106 and the remote UE 1102 (e.g., relay link configuration information, bearer configuration information). In 1118, the remote UE 1102 may connect with the gNB 1106. In 1120, remote UE 1102 may complete RRC connection reestablishment with gNB 1106 by providing an RRC reestablishment complete message to relay UE 1104, and in 1122, relay UE 1104 may provide an RRC reestablishment complete message to gNB 1106 using a relay SRB and indicate identification information of remote UE 1102. In 1124, gNB 1106 may also connect with remote UE 1102.

[0116] Fig.12Aspects of an exemplary scenario according to some embodiments are shown, in which a single remote UE attempts to resume an RRC connection with a gNB via a relay UE. As shown, in the illustrated scenario, in 1208, remote UE 1202 may provide an RRC recovery request to relay UE 1204. In 1210, remote UE 1202 and relay UE 1204 may be connected. In 1212, relay UE 1204 may provide an RRC recovery request to gNB 1206 using a relay SRB and indicate identification information of remote UE 1202. In 1214, gNB 1206 may provide an RRC recovery message to relay UE 1204 using the relay SRB. The RRC resume message may include C RNTI information of the remote UE 1202, as well as relay link configuration information, bearer configuration information, Uu data radio bearer configuration information, mapping configuration information, and / or any of various information that supports resuming the remote RRC connection between the gNB 1206 and the remote UE 1202. In 1216, the relay UE 1204 may provide the RRC resume message to the remote UE 1202, including at least some of the information received from the gNB 1206, such as any information required by the remote UE 1202 as part of resuming the remote RRC connection between the gNB 1206 and the remote UE 1202 (e.g., relay link configuration information, bearer configuration information). In 1218, the remote UE 1202 may connect with the gNB 1206. In 1220, remote UE 1202 may complete the RRC recovery process with gNB 1206 by providing an RRC recovery complete message to relay UE 1204, and in 1222, relay UE 1204 may provide an RRC recovery complete message to gNB 1206 using a relay SRB and indicate identification information of remote UE 1202. In 1224, gNB 1206 may also connect with remote UE 1202.

[0117] Fig.13Aspects of an exemplary scenario according to some embodiments are shown, in which a gNB releases a remote RRC connection with a remote UE via a relay UE; as shown, in the illustrated scenario, in 1308, remote UE 1302 and relay UE 1304 may each be connected to each other and have an RRC connection with gNB 1306. In 1310, gNB 1306 may provide an RRC release message to relay UE 1304 using a relay SRB. The RRC release message may include identification information of remote UE 1302, as well as any of relay link configuration information, bearer configuration information, Uu data radio bearer configuration information, mapping configuration information, and / or various information that supports releasing the remote RRC connection between gNB 1306 and remote UE 1302. In 1312, relay UE 1304 may provide an RRC release message to remote UE 1302, including at least some information received from gNB 1306, such as any information required by remote UE 1302 as part of releasing the remote RRC connection between gNB 1306 and remote UE 1302 (e.g., relay link configuration information, bearer configuration information). In 1314, remote UE 1302 may enter an idle mode as a result of the remote RRC connection being released. Note that, alternatively, at least according to some embodiments, remote UE 1302 may be released to an inactive mode.

[0118] Fig.14Aspects of an exemplary scenario according to some embodiments are shown, in which a gNB reconfigures a remote RRC connection with a remote UE via a relay UE; as shown, in the illustrated scenario, in 1408, remote UE 1402 and relay UE 1404 may each be connected to each other and have an RRC connection with gNB 1406. In 1410, gNB 1406 may provide an RRC reconfiguration message to relay UE 1404 using a relay SRB. The RRC reconfiguration message may include identification information of remote UE 1402, as well as relay link configuration information, bearer configuration information, Uu data radio bearer configuration information, mapping configuration information, and / or any of various information that supports reconfiguring the remote RRC connection between gNB 1406 and remote UE 1402. In 1412, relay UE 1404 may provide an RRC reconfiguration message to remote UE 1402, including at least some of the information received from gNB 1406, such as any information required by remote UE 1402 as part of reconfiguring the remote RRC connection between gNB 1406 and remote UE 1402 (e.g., relay link configuration information, bearer configuration information). In 1414, remote UE 1402 may provide an RRC reconfiguration complete message to relay UE 1404, and in 1416, relay UE 1404 may provide the RRC reconfiguration complete message to gNB 1406 using the relay SRB and indicate identification information of remote UE 1402.

[0119] In addition to providing a framework for relaying RRC messages between a remote UE and a gNB, a framework for detecting and handling link failures in conjunction with a remote RRC connection may also be provided. As one aspect of such a framework, it may be that the relay SRB is configured with a radio link control (RLC) acknowledgement mode (AM). Therefore, if the RRC message transmission of the remote UE fails due to a link failure between the relay UE and the network, the relay UE may detect the RLC failure and trigger a radio link failure (RLF). In the Uu link, the relay UE may perform an RRC connection reestablishment procedure or a secondary cell group (SCG) failure recovery procedure. With respect to the relay link, the relay UE may send a Uu link failure indication to the remote UE, or may send a suspend relay link indication to the remote UE (and possibly any other remote UE connected to the relay UE), or may directly shut down the relay link.

[0120] The remote UE may perform link reselection based on the Uu link failure. For example, if the ongoing procedure is for establishment / reestablishment / recovery, the remote UE may retry the procedure in the newly selected link. If the ongoing exchange is for another procedure such as reconfiguration, the remote UE may perform the reestablishment procedure in the newly selected link if access stratum (AS) security is activated. Otherwise, if AS security is not activated, the UE may perform the RRC connection establishment procedure in the newly selected link. Note that if the remote UE's RRC message transmission failure occurs while the network is transmitting to the relay UE, the network may be able to reconfigure the relay SRB and resend the message.

[0121] Figures 15 to 17 is a signal flow diagram illustrating aspects of various possible scenarios in which an RRC procedure between a remote UE and a gNB fails due to a link failure between a relay UE and a gNB according to various embodiments.

[0122] Specifically, Fig.15Some aspects of an exemplary scenario according to some embodiments are shown, in which a remote RRC connection establishment fails due to a link failure between a relay UE and a gNB. As shown, in the illustrated scenario, in 1508, a remote UE 1502 may provide an RRC connection request to a relay UE 1504. In 1510, the remote UE 1502 and the relay UE 1504 may be connected. In 1512, the relay UE 1504 may provide an RRC connection request to the gNB 1506 using a relay SRB and indicate identification information of the remote UE 1502. In 1514, the gNB 1506 may provide an RRC connection establishment message to the relay UE 1504 using the relay SRB. In 1516, the relay UE 1504 may provide an RRC connection setup message to the remote UE 1502. In 1518, the remote UE 1502 may connect with the gNB 1506. In 1520, the remote UE 1502 may attempt to complete the RRC connection establishment with the gNB 1506 by providing an RRC setup complete message to the relay UE 1504, and in 1522, the relay UE 1504 may provide the RRC setup complete message to the gNB 1506 using the relay SRB and indicate the identification information of the remote UE 1502. However, the RRC setup complete message delivery may fail, and in 1524, the relay UE 1504 may declare Uu link RLF. In 1526, the relay UE 1504 may stop providing discovery broadcasts, and in 1528, an indication may be provided to the remote UE 1502 to suspend the relay link between the remote UE 1502 and the relay UE 1504. In 1530, the remote UE 1502 may enter an idle mode. In 1532, the relay UE 1504 and the gNB 1506 may perform an RRC connection reestablishment procedure. In 1534, remote UE 1502 may perform link reselection. In 1536, relay UE 1504 may resume providing discovery broadcasts. In 1538, remote UE 1502 may transmit a new RRC connection request to relay UE 1504 or possibly to another wireless device, for example, depending on the result of link selection.

[0123] Fig.16Some aspects of an exemplary scenario according to some embodiments are shown, in which a remote RRC connection reestablishment fails due to a link failure between a relay UE and a gNB. As shown, in the illustrated scenario, in 1608, the remote UE 1602 may provide an RRC reestablishment request to the relay UE 1604. In 1610, the remote UE 1602 and the relay UE 1604 may be connected. In 1612, the relay UE 1604 may provide an RRC reestablishment request to the gNB 1606 using a relay SRB and indicate identification information of the remote UE 1602. However, the RRC reestablishment request delivery may fail, and in 1614, the relay UE 1604 may declare a Uu link RLF. In 1616, the relay UE 1604 may stop providing discovery broadcasts, and in 1618, an indication that a Uu failure has occurred may be provided to the remote UE 1602. In 1620, the relay UE 1604 and the gNB 1606 may perform an RRC connection reestablishment procedure. In 1622, the remote UE 1602 may perform a link reselection. In 1624, the relay UE 1604 may resume providing discovery broadcasts. In 1626, the remote UE 1602 may transmit a new RRC reestablishment request to the relay UE 1604 or possibly to another wireless device, for example, depending on the result of the link selection.

[0124] Fig.171706. The present invention provides a signal flow diagram illustrating aspects of an exemplary scenario according to some embodiments, in which a remote RRC connection recovery failure occurs due to a link failure between a relay UE and a gNB. As shown, in the illustrated scenario, in 1708, a remote UE 1702 may provide an RRC recovery request to a relay UE 1704. In 1710, the remote UE 1702 and the relay UE 1704 may be connected. In 1712, the relay UE 1704 may provide an RRC recovery request to the gNB 1706 using a relay SRB and indicate identification information of the remote UE 1702. In 1714, the gNB 1706 may provide an RRC recovery message to the relay UE 1704 using a relay SRB. In 1716, the relay UE 1704 may provide an RRC recovery message to the remote UE 1702. In 1718, the remote UE 1702 may connect with the gNB 1706. In 1720, the remote UE 1702 may attempt to complete the RRC recovery process with the gNB 1706 by providing an RRC recovery complete message to the relay UE 1704, and in 1722, the relay UE 1704 may provide the RRC recovery complete message to the gNB 1706 using the relay SRB and indicate the identification information of the remote UE 1702. However, the RRC recovery complete message delivery may fail, and in 1724, the relay UE 1704 may declare Uu link RLF. In 1726, the relay UE 1704 may stop providing discovery broadcasts, and in 1728, an indication may be provided to the remote UE 1702 to suspend the relay link between the remote UE 1702 and the relay UE 1704. In 1730, the remote UE 1702 may enter an inactive mode. In 1732, the relay UE 1704 and the gNB 1706 may perform an RRC connection reestablishment process. In 1734, the remote UE 1702 may perform link reselection. In 1736, the relay UE 1704 may resume providing discovery broadcasts. In 1738, the remote UE 1702 may transmit a new RRC resume request to the relay UE 1704 or possibly to another wireless device, for example, depending on the result of the link selection.

[0125] In addition to detecting Uu link failures, it may also be useful to provide relay link failure detection and handling techniques. As one such possibility, for a bidirectional RRC procedure (e.g., where RRC messages are provided in both the uplink and downlink), the relay UE may be able to rely on a validity timer to control the RRC response message from the remote UE over the relay link. For example, Fig.18Aspects of an exemplary scenario according to some embodiments are shown, in which a response validity timer is used by a relay UE to detect a link failure between a relay UE and a remote UE; as shown, in the illustrated scenario, in 1808, a remote UE 1802 and a relay UE 1804 may be initially connected. In 1810, the gNB 1806 may provide an RRC reconfiguration message to the relay UE 1804 using a relay SRB. The RRC reconfiguration message may include identification information of the remote UE 1802. In 1812, the relay UE 1804 may provide the RRC reconfiguration message to the remote UE 1802, including at least some of the information received from the gNB 1806. In 1814, when the RRC message is sent to the remote UE 1802, the relay UE 1804 may start the response validity timer. Note that when a response is received from the remote UE 1802, the relay UE 1804 may stop the timer. In 1816, remote UE 1802 may transmit an RRC reconfiguration complete message to relay UE 1804, but relay UE 1804 may not receive the message. In 1818, a response validity timer may expire, and relay UE 1804 may consider that an RRC message transmission failure has occurred on the relay link. Note that such a response validity timer may be configured by relay UE 1804 itself, or by gNB 1806, for example, in an RRC message.

[0126] Fig.19 is a signal flow diagram illustrating aspects of an exemplary scenario according to some embodiments, in which a response validity timer is used by a relay UE to detect a PC5 interface failure between the relay UE and a remote UE. Fig.19 The scenario may be similar in at least some respects to Fig.18, but more specifically, the PC5 RRC message validity timer may be used to detect relay link failure when the PC5 interface is used for a relay link between a remote and relay device. As shown, in the illustrated scenario, in 1908, the remote UE 1902 and the relay UE 1904 may be initially connected. In 1910, the gNB 1906 may provide an RRC reconfiguration message to the relay UE 1904, which may include an indication of the PC5 message validity timer configuration. In 1912, the relay UE 1904 may provide the PC5 reconfiguration message to the remote UE 1902. In 1914, when the PC5 reconfiguration message is sent to the remote UE 1902, the relay UE 1904 may start a response validity timer. Note that when a response is received from the remote UE 1902, the relay UE 1904 may stop the timer. In 1916, the remote UE 1902 may transmit a PC5 reconfiguration complete message to the relay UE 1904, but the relay UE 1904 may not receive the message. In 1918, the response validity timer may expire and the relay UE 1904 may consider that a relay link failure has occurred. It is noted that such a PC5 RRC message validity timer may be configured by the relay UE 1904 itself, or by the gNB 1906, for example, in an RRC message, as shown. It is also noted that in a general sense, in the case where the two UEs are equivalent UEs performing sidelink communications, this method can be used to detect a link failure of either UE. In addition, it is noted that such a method can be used in conjunction with any of a variety of PC5 RRC messages, such as a PC5 reconfiguration (e.g., as shown), a UE capability request, and / or any of a variety of other possible messages.

[0127] At least in some cases, a similar method of using a response timer to detect relay link failure may also or alternatively be used by the remote UE. For example, for a two-way RRC procedure, the remote UE can also rely on a validity timer to control the RRC response message from the relay UE over the relay link. Fig. 20Aspects of an exemplary scenario according to some embodiments are shown, in which the remote UE uses a response guard timer for a link failure between a remote UE and a relay UE. As shown, in the illustrated scenario, in 2008, the gNB 2006 may indicate the guard timer duration to the relay UE 2004, and the relay UE 2002 may broadcast the guard timer duration (e.g., as a configuration parameter) as part of discovery, or may send it to the remote UE as part of connection establishment. In 2010, the relay UE 2004 may be connected, and in 2012, the remote UE 2002 may be inactive. In 2014, the remote UE 2002 may provide an RRC recovery request to the relay UE 2004, and in 2016, a response guard timer may be started, which may be stopped after the remote UE 2002 receives a response from the relay UE 2004. However, the RRC recovery request delivery may fail, so in 2018, the response guard timer may expire and a relay link transmission failure is detected. In 2020, the remote UE 2002 may detect a relay link failure based on the relay link transmission failure. In 2022, the remote UE 2002 may perform link selection, and in 2024, may transmit an RRC recovery request to again attempt to recover the RRC connection with the gNB 2006, possibly to the relay UE 2004, or possibly to another wireless device, e.g., based on the result of the link selection. Note that the relay UE may reuse the current RRC timer (e.g., t319) as the guard timer for the remote UE, or the gNB may configure a different expiration duration for the remote UE (e.g., as in the illustrated scenario), or the relay UE may autonomously configure the guard timer duration among various possibilities for determining the guard timer duration.

[0128] When the relay UE detects that the relay link fails, for example, using Figure 18 to Figure 19 The relay UE may notify the network of the relay link failure, at least according to some embodiments, using a timer-based approach in the illustrated scenario, or using any of a variety of other possible approaches (e.g., based on RLC failure, radio link failure detection based on radio link monitoring, etc.). In such a scenario, the network may be able to immediately terminate the current RRC procedure with the remote UE, and the relay UE may delete the remote UE, for example, by itself or according to network configuration.

[0129] Figure 21 to Figure 23 is a signal flow diagram illustrating aspects of link failure handling for various example scenarios according to some embodiments, where a remote RRC procedure fails due to a link failure between a relay UE and a remote UE.

[0130] More specifically, Fig.212104. 2104 may provide an RRC connection request to the relay UE 2104. In 2110, the remote UE 2102 and the relay UE 2104 may be connected. In 2112, the relay UE 2104 may provide an RRC connection request to the gNB 2106 using the relay SRB and indicate the identification information of the remote UE 2102. In 2114, the gNB 2106 may provide an RRC connection establishment message to the relay UE 2104 using the relay SRB. In 2116, the relay UE 2104 may provide an RRC connection setup message to the remote UE 2102. In 2118, the remote UE 2102 may connect with the gNB 2106. In 2120, the remote UE 2102 may attempt to complete the RRC connection establishment with the gNB 2106 by providing an RRC setup complete message to the relay UE 2104. However, the RRC setup complete message delivery may fail, and in 2122, the remote UE 2102 may detect a relay link failure. In 2124, the remote UE 2102 may perform link selection, and in 2126, an attempt to establish the RRC connection again using the newly selected link may be triggered. In 2128, the relay UE 2104 may also detect the relay link failure. In 2130, the relay UE 2104 may provide a remote UE relay link transmission failure indication to the gNB 2106, which may indicate identification information of the remote UE 2102. In 2132, the gNB 2106 may terminate the connection establishment process, and in 2134, a remove remote UE message may be provided to the relay UE 2104, including indicating identification information for the remote UE 2102.

[0131] Fig. 22Some aspects of an exemplary scenario according to some embodiments are shown, in which remote RRC connection reestablishment fails due to a link failure between a relay UE and a remote UE. As shown, in the illustrated scenario, in 2208, the remote UE 2202 may provide an RRC reestablishment request to the relay UE 2204. In 2210, the remote UE 2202 and the relay UE 2204 may be connected. In 2212, the relay UE 2204 may provide an RRC reestablishment request to the gNB 2206 using a relay SRB and indicate identification information of the remote UE 2202. In 2214, the gNB 2206 may provide an RRC reestablishment message to the relay UE 2204 using a relay SRB. In 2216, the relay UE 2204 may provide an RRC reestablishment message to the remote UE 2202. However, the RRC reestablishment message delivery may fail, and in 2218, the relay UE 2204 may detect a relay link failure. In 2220, relay UE 2204 may provide an indication (e.g., as a best action) to release the relay link to remote UE 2202. In 2222, remote UE 2202 may perform link selection, and in 2224, may trigger an attempt to reestablish the RRC connection using the newly selected link again. In 2226, relay UE 2204 may provide a remote UE relay link transmission failure indication to gNB 2206, which may indicate identification information of remote UE 2202. In 2228, gNB 2206 may terminate the reestablishment process, and in 2230, may provide a remove remote UE message to relay UE 2204, including indicating identification information for remote UE 2202.

[0132] Fig.23Some aspects of an exemplary scenario according to some embodiments are shown, in which a remote RRC connection recovery failure occurs due to a link failure between a relay UE and a remote UE. As shown, in the illustrated scenario, in 2308, the remote UE 2302 may provide an RRC recovery request to the relay UE 2304. In 2310, the remote UE 2302 and the relay UE 2304 may be connected. In 2312, the relay UE 2304 may provide an RRC recovery request to the gNB 2306 using a relay SRB and indicate identification information of the remote UE 2302. In 2314, the gNB 2306 may provide an RRC recovery message to the relay UE 2304 using a relay SRB. In 2316, the relay UE 2304 may provide an RRC recovery message to the remote UE 2302. In 2318, the remote UE 2302 may connect with the gNB 2306. In 2320, the remote UE 2302 may attempt to complete the RRC recovery process with the gNB 2304 by providing an RRC recovery complete message to the relay UE 2306. However, the RRC recovery message delivery may fail, and in 2322, the remote UE 2302 may detect a relay link failure. In 2324, the remote UE 2302 may perform link selection, and in 2326, an attempt may be triggered to reestablish the RRC connection using the newly selected link. In 2328, the relay UE 2304 may also detect the relay link failure. In 2330, the relay UE 2304 may provide a remote UE relay link transmission failure indication to the gNB 2306, which may indicate identification information of the remote UE 2302. In 2332, the gNB 2306 may terminate the recovery process, and in 2334, a remove remote UE message may be provided to the relay UE 2304, including indicating identification information for the remote UE 2302.

[0133] In the following, additional exemplary embodiments are provided.

[0134] One set of embodiments may include an apparatus comprising: a processor configured to cause a relay wireless device to: establish a radio resource control connection with a cellular base station; receive a radio resource control connection request from a remote wireless device; and relay radio resource control messages between the remote wireless device and the cellular base station.

[0135] According to some embodiments, the processor is further configured to cause the relay wireless device to: transmit a discovery broadcast message indicating that the relay wireless device supports relay radio resource control messages; wherein the radio resource control connection request is received from the remote wireless device at least in part based on a response to the discovery broadcast message.

[0136] According to some embodiments, the processor is also configured to cause the relay wireless device to: detect a link failure of a wireless link between the relay wireless device and the cellular base station; and provide an indication of a link failure of the wireless link between the relay wireless device and the cellular base station to the remote wireless device.

[0137] According to some embodiments, the indication of a link failure of a wireless link between a relay wireless device and a cellular base station includes one or more of the following: an indication that a link failure has occurred in the wireless link between the relay wireless device and the cellular base station; an indication to suspend the wireless link between the relay wireless device and the remote wireless device; or an indication to release the wireless link between the relay wireless device and the remote wireless device.

[0138] According to some embodiments, the processor is further configured to cause the relay wireless device to: cease providing discovery broadcast messages to the remote wireless device based at least in part on a link failure of a wireless link between the relay wireless device and a cellular base station.

[0139] According to some embodiments, the processor is further configured to cause the relay wireless device to: detect a link failure of a wireless link between the relay wireless device and a remote wireless device; and provide an indication of a link failure of the wireless link between the relay wireless device and the remote wireless device to a cellular base station.

[0140] According to some embodiments, the processor is further configured to cause the relay wireless device to: receive an indication to release the remote wireless device from the cellular base station in response to an indication of a link failure of a wireless link between the relay wireless device and the remote wireless device.

[0141] According to some embodiments, the processor is further configured to cause the relay wireless device to: start a response validity timer based at least in part on relaying a radio resource control message to a remote wireless device; and based on expiration of the response validity timer, detect a link failure of a wireless link between the relay wireless device and the remote wireless device.

[0142] According to some embodiments, the processor is further configured to enable the relay wireless device to: relay radio resource control messages between the cellular base station and each of a plurality of remote wireless devices, wherein each radio resource control message relayed between the cellular base station and the corresponding remote wireless device includes remote wireless device identification information for the corresponding remote wireless device.

[0143] Another set of embodiments may include a cellular base station comprising: an antenna; a radio component operably coupled to the antenna; and a processor operably coupled to the radio component; wherein the cellular base station is configured to: receive a radio resource control message from a relay wireless device, wherein the radio resource control message includes information relayed by the relay wireless device from a remote wireless device to the cellular base station; and transmit the radio resource control message to the relay wireless device, wherein the radio resource control message includes information configured to be relayed by the relay wireless device to the remote wireless device.

[0144] According to some embodiments, the radio resource control message comprises a radio resource control connection establishment request, wherein the radio resource control message comprises a radio resource control connection setup message.

[0145] According to some embodiments, the radio resource control message comprises a radio resource control connection re-establishment request, wherein the radio resource control message comprises a radio resource control re-establishment message.

[0146] According to some embodiments, the radio resource control message comprises a radio resource control connection restoration request, wherein the radio resource control message comprises a radio resource control restoration message.

[0147] According to some embodiments, the cellular base station is further configured to: transmit a radio resource control release message to the relay wireless device, wherein the radio resource control release message is configured to be relayed by the relay wireless device to the remote wireless device.

[0148] According to some embodiments, the cellular base station is further configured to: transmit a radio resource control reconfiguration message to the relay wireless device, wherein the radio resource control reconfiguration message is configured to be relayed by the relay wireless device to the remote wireless device.

[0149] Another set of embodiments may include a method comprising: by a first wireless device: providing a first radio resource control message to a second wireless device, wherein the first radio resource control message includes information configured to be relayed by the second wireless device to a cellular base station; and receiving a second radio resource control message from the second wireless device, wherein the second radio resource control message includes information relayed by the second wireless device from the cellular base station to the first wireless device.

[0150] According to some embodiments, the method further includes performing link selection to determine a wireless link over which to attempt to establish a relayed radio resource control connection with a cellular base station, wherein a first radio resource control message is provided to a second wireless device based at least in part on the link selection.

[0151] According to some embodiments, the method also includes: starting a response protection timer based at least in part on providing a radio resource control message to the second wireless device, wherein the response protection timer is stopped when a response to the resource control message is received from the second wireless device; determining that a link failure of the wireless link between the first wireless device and the second wireless device has occurred based at least in part on expiration of the response protection timer; and performing link selection based at least in part on the link failure of the wireless link between the first wireless device and the second wireless device to determine a wireless link on which to attempt to establish a relayed radio resource control connection with a cellular base station.

[0152] According to some embodiments, the method also includes: receiving an indication to release a wireless link between the first wireless device and the second wireless device, and performing link selection based at least in part on the indication to release the wireless link between the first wireless device and the second wireless device to determine a wireless link on which to attempt to establish a relayed radio resource control connection with a cellular base station.

[0153] According to some embodiments, the first radio resource control message comprises one of: a radio resource control connection establishment request; a radio resource control connection re-establishment request; or a radio resource control connection recovery request.

[0154] Yet another example embodiment may include a method, comprising: performing, by a wireless device: any or all of the foregoing examples.

[0155] Another exemplary embodiment may include a wireless device comprising: an antenna; a radio component coupled to the antenna; and a processing element operably coupled to the radio component, wherein the device is configured to implement any or all of the foregoing examples.

[0156] Another example embodiment may include an apparatus comprising: a processing element configured to cause a wireless device to implement any or all of the foregoing examples.

[0157] Another exemplary set of embodiments may include a non-transitory computer-accessible storage medium including program instructions that, when executed at a device, cause the device to implement any or all portions of any of the foregoing examples.

[0158] Another exemplary set of embodiments may include a computer program comprising instructions for performing any or all portions of any of the foregoing examples.

[0159] Another exemplary set of embodiments may include an apparatus including means for performing any or all of the elements of any of the preceding examples.

[0160] It is well known that the use of personally identifiable information should be subject to privacy policies and practices that are generally recognized to meet or exceed industry or government requirements for maintaining user privacy. Specifically, personally identifiable information data should be managed and processed to minimize the risk of unintentional or unauthorized access or use, and the nature of the authorized use should be clearly stated to users.

[0161] In addition to the exemplary embodiments described above, more embodiments of the present disclosure may be implemented in any of a variety of forms. For example, some embodiments may be implemented as computer-implemented methods, computer-readable storage media, or computer systems. Other embodiments may be implemented using one or more custom-designed hardware devices such as ASICs. Other embodiments may be implemented using one or more programmable hardware elements such as FPGAs.

[0162] In some embodiments, a non-transitory computer-readable storage medium may be configured such that it stores program instructions and / or data, wherein if the program instructions are executed by a computer system, the computer system is caused to perform a method, such as any one of the method embodiments described herein, or any combination of the method embodiments described herein, or any subset of any of the method embodiments described herein or any combination of such subsets.

[0163] In some embodiments, an apparatus (e.g., UE 106 or 107) may be configured to include a processor (or a group of processors) and a memory medium, wherein the memory medium stores program instructions, wherein the processor is configured to read and execute the program instructions from the memory medium, wherein the program instructions are executable to implement any of the various method implementations described herein (or any combination of the method implementations described herein, or any subset of any method implementations described herein, or any combination of such subsets). The device may be implemented in any of various forms.

[0164] Although the above embodiments have been described in considerable detail, numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to encompass all such variations and modifications.

Claims

1. A method comprising: By relay wireless device: receiving a radio resource control (RRC) setup complete message from a remote wireless device; as well as A remote wireless device identifier of the remote wireless device and the RRC setup complete message are sent to the base station over a Uu link between the relay wireless device and the base station to establish an RRC connection between the remote wireless device and the base station.

2. The method according to claim 1, further comprising: transmitting a discovery broadcast message, the discovery broadcast message indicating that the relay wireless device supports relay RRC messages; as well as Based at least in part on receiving an RRC connection request from the remote wireless device in response to the discovery broadcast message.

3. The method according to claim 1, further comprising: detecting a link failure of a wireless link between the relay wireless device and the base station; as well as An indication of a link failure of a wireless link between the relay wireless device and the base station is provided to the remote wireless device.

4. The method of claim 3, wherein the indication of a link failure of the wireless link between the relay wireless device and the base station comprises one or more of: an indication that a link failure of a wireless link between the relay wireless device and the base station has occurred; an indication to suspend a wireless link between the relay wireless device and the remote wireless device; or An indication to release a wireless link between the relay wireless device and the remote wireless device.

5. The method according to claim 3, further comprising: Based at least in part on a link failure of a wireless link between the relay wireless device and the base station, transmission of discovery broadcast messages to the remote wireless device is ceased.

6. The method according to claim 1, further comprising: detecting a link failure of a wireless link between the relay wireless device and the remote wireless device; as well as An indication of a link failure of a wireless link between the relay wireless device and the remote wireless device is provided to the base station.

7. The method according to claim 6, further comprising: In response to an indication of a link failure of a wireless link between the relay wireless device and the remote wireless device, an indication to release the remote wireless device from the base station is received.

8. An apparatus comprising: A processor configured to cause the relay wireless device to: receiving a radio resource control (RRC) setup complete message from a remote wireless device; as well as A remote wireless device identifier of the remote wireless device and the RRC setup complete message are sent to the base station over a Uu link between the relay wireless device and the base station to establish an RRC connection between the remote wireless device and the base station.

9. The apparatus of claim 8, wherein the processor is further configured to cause the relay wireless device to: transmitting a discovery broadcast message indicating that the relay wireless device supports relay RRC messages; and The RRC connection request is received from the remote wireless device based at least in part on a response to the discovery broadcast message.

10. The apparatus of claim 8, wherein the processor is further configured to cause the relay wireless device to: detecting a link failure of a wireless link between the relay wireless device and the base station; and An indication of a link failure of a wireless link between the relay wireless device and the base station is provided to the remote wireless device.

11. The apparatus of claim 10, wherein the indication of a link failure of the wireless link between the relay wireless device and the base station comprises one or more of: an indication that a link failure of a wireless link between the relay wireless device and the base station has occurred; an indication to suspend a wireless link between the relay wireless device and the remote wireless device; or An indication to release a wireless link between the relay wireless device and the remote wireless device.

12. The apparatus of claim 10, wherein the processor is further configured to cause the relay wireless device to: Based at least in part on a link failure of a wireless link between the relay wireless device and the base station, transmission of discovery broadcast messages to the remote wireless device is ceased.

13. The apparatus of claim 8, wherein the processor is further configured to cause the relay wireless device to: detecting a link failure of a wireless link between the relay wireless device and the remote wireless device; and An indication of a link failure of a wireless link between the relay wireless device and the remote wireless device is provided to the base station.

14. The apparatus of claim 13, wherein the processor is further configured to cause the relay wireless device to: In response to an indication of a link failure of a wireless link between the relay wireless device and the remote wireless device, an indication to release the remote wireless device from the base station is received.

15. A relay wireless device, comprising: Radio components; and a processor operably coupled to the radio, wherein the relay wireless device is configured to: receiving a radio resource control (RRC) setup complete message from a remote wireless device; as well as A remote wireless device identifier of the remote wireless device and the RRC setup complete message are sent to the base station over a Uu link between the relay wireless device and the base station to establish an RRC connection between the remote wireless device and the base station.

16. The relay wireless device according to claim 15, wherein the relay wireless device is further configured to: transmitting a discovery broadcast message indicating that the relay wireless device supports relay RRC messages; and An RRC connection request is received from the remote wireless device based at least in part on response to the discovery broadcast message.

17. The relay wireless device according to claim 15, wherein the relay wireless device is further configured to: detecting a link failure of a wireless link between the relay wireless device and the base station; and An indication of a link failure of a wireless link between the relay wireless device and the base station is provided to the remote wireless device.

18. The relay wireless device of claim 17, wherein the indication of a link failure of a wireless link between the relay wireless device and the base station comprises one or more of the following: an indication that a link failure of a wireless link between the relay wireless device and the base station has occurred; an indication to suspend a wireless link between the relay wireless device and the remote wireless device; or An indication to release a wireless link between the relay wireless device and the remote wireless device.

19. The relay wireless device according to claim 17, wherein the relay wireless device is further configured to: Based at least in part on a link failure of a wireless link between the relay wireless device and the base station, transmission of discovery broadcast messages to the remote wireless device is ceased.

20. The relay wireless device of claim 15, wherein the relay wireless device is further configured to: detecting a link failure of a wireless link between the relay wireless device and the remote wireless device; and An indication of a link failure of a wireless link between the relay wireless device and the remote wireless device is provided to the base station.

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