WO2019034241A1

WO2019034241A1 - Responding to radio access network paging failures

Info

Publication number: WO2019034241A1
Application number: PCT/EP2017/070632
Authority: WO
Inventors: Dimitrios Karampatsis
Original assignee: Motorola Mobility Llc
Priority date: 2017-08-14
Filing date: 2017-08-14
Publication date: 2019-02-21

Abstract

Apparatuses, methods, and systems are disclosed for responding to radio access network paging failures. One apparatus (300) includes a receiver (312) that receives (602) an indication of radio access network paging failure. The apparatus (300) includes a processor (302) that, in response to receiving the indication of radio access network paging failure, determines (604) to maintain user plane connections for active protocol data unit sessions.

Description

RESPONDING TO RADIO ACCESS NETWORK PAGING FAILURES

FIELD

[0001] The subject matter disclosed herein relates generally to wireless communications and more particularly relates to responding to radio access network paging failures.

BACKGROUND

[0002] The following abbreviations are herewith defined, at least some of which are referred to within the following description: Third Generation Partnership Project ("3GPP"), Positive- Acknowledgment ("ACK"), Core Access and Mobility Management Function ("AMF"), Binary Phase Shift Keying ("BPSK"), Clear Channel Assessment ("CCA"), Cyclic Prefix ("CP"), Cyclical Redundancy Check ("CRC"), Channel State Information ("CSI"), Common Search Space ("CSS"), Discrete Fourier Transform Spread ("DFTS"), Downlink Control Information ("DCI"), Downlink ("DL"), Downlink Pilot Time Slot ("DwPTS"), Enhanced Clear Channel Assessment ("eCCA"), Enhanced LTE ("eLTE"), Enhanced Mobile Broadband ("eMBB"), Evolved Node B ("eNB"), Evolved Packet Core ("EPC"), European Telecommunications Standards Institute ("ETSI"), Evolved, Universal Terrestrial Radio Access ("E-UTRA"), Frame Based Equipment ("FBE"), Frequency Division Duplex ("FDD"), Frequency Division Multiple Access ("FDMA"), Frequency Division Orthogonal Cover Code ("FD-OCC"), Guard Period ("GP"), Hybrid Automatic Repeat Request ("HARQ"), Internet-of-Things ("IoT"), Licensed Assisted Access ("LAA"), Load Based Equipment ("LBE"), Listen-Before-Talk ("LBT"), Long Term Evolution ("LTE"), Multiple Access ("MA"), Mobility Management Entity ("MME"), Modulation Coding Scheme ("MCS"), Machine Type Communication ("MTC"), Multiple Input Multiple Output ("MIMO"), Multi User Shared Access ("MUSA"), Narrowband ("NB"), Negative- Acknowledgment ("NACK") or ("NAK"), Network Exposure Function ("NEF"), Next Generation Node B ("gNB"), New Radio ("NR"), Non-Orthogonal Multiple Access ("NOMA"), Orthogonal Frequency Division Multiplexing ("OFDM"), Primary Cell ("PCell"), Physical Broadcast Channel ("PBCH"), Physical Downlink Control Channel ("PDCCH"), Physical Downlink Shared Channel ("PDSCH"), Pattern Division Multiple Access ("PDMA"), Physical Hybrid ARQ Indicator Channel ("PHICH"), Physical Random Access Channel ("PRACH"), Physical Resource Block ("PRB"), Physical Uplink Control Channel ("PUCCH"), Physical Uplink Shared Channel ("PUSCH"), Quality of Service ("QoS"), Quadrature Phase Shift Keying ("QPSK"), Radio Access Network ("RAN"), Radio Resource Control ("RRC"), Random Access Procedure ("RACH"), Random Access Response ("RAR"), Radio Network Temporary Identifier ("RNTI"), Reference Signal ("RS"), Remaining Minimum System Information ("RMSI"), Resource Spread Multiple Access ("RSMA"), Round Trip Time ("RTT"), Receive ("RX"), Sparse Code Multiple Access ("SCMA"), Scheduling Request ("SR"), Single Carrier Frequency Division Multiple Access ("SC- FDMA"), Secondary Cell ("SCell"), Shared Channel ("SCH"), Signal-to-Interference-Plus-Noise Ratio ("SINR"), System Information Block ("SIB"), Session Management Function ("SMF"), Synchronization Signal ("SS"), Transport Block ("TB"), Transport Block Size ("TBS"), Time- Division Duplex ("TDD"), Time Division Multiplex ("TDM"), Time Division Orthogonal Cover Code ("TD-OCC"), Transmission Time Interval ("TTI"), Transmit ("TX"), Unified Data Management ("UDM"), Uplink Control Information ("UCI"), User Entity/Equipment (Mobile Terminal) ("UE"), Uplink ("UL"), Universal Mobile Telecommunications System ("UMTS"), Uplink Pilot Time Slot ("UpPTS"), User Plane ("UP"), User Plane Function ("UPF"), Ultra- reliability and Low-latency Communications ("URLLC"), and Worldwide Interoperability for Microwave Access ("WiMAX"). As used herein, "HARQ-ACK" may represent collectively the Positive Acknowledge ("ACK") and the Negative Acknowledge ("NACK"). ACK means that a TB is correctly received while NACK (or NAK) means a TB is erroneously received.

[0003] In certain wireless communications networks, a RAN paging failure may be persistent. In such networks, various devices in the networks may not know how to handle the RAN paging failure.

BRIEF SUMMARY

[0004] Apparatuses for responding to radio access network paging failures are disclosed. Methods and systems also perform the functions of the apparatus. In one embodiment, the apparatus includes a receiver that receives an indication of radio access network paging failure. In various embodiments, the apparatus includes a processor that, in response to receiving the indication of radio access network paging failure, determines to maintain (e.g., not release) user plane connections for active protocol data unit sessions.

[0005] In one embodiment, the apparatus includes a transmitter that transmits a message to a remote unit including an indication of the radio access network paging failure in response to the receiver receiving the indication of radio access network paging failure. In a further embodiment, in response to the transmitter transmitting the message to the remote unit including the indication of the radio access network paging failure, the receiver receives an acknowledgement of the message transmitted to the remote unit. In certain embodiments, the acknowledgment is received from a target radio access network, and the target radio access network transmits the acknowledgment in response to receiving a resume message from the remote unit. In various embodiments, the indication of radio access network paging failure is received as part of an access network context release request. In some embodiments, the indication of radio access network paging failure is received as part of a notification that radio access network paging failed. In some embodiments, the processor determines a state of a remote unit based on whether a radio resource control connection was resumed by the remote unit.

[0006] A method for responding to radio access network paging failures, in one embodiment, includes receiving an indication of radio access network paging failure. In various embodiments, the method includes, in response to receiving the indication of radio access network paging failure, determining to maintain (e.g., not release) user plane connections for active protocol data unit sessions.

[0007] An apparatus for responding to radio access network paging failures, in one embodiment, includes a receiver that receives a message comprising an indication of a radio access network paging failure. In various embodiments, the apparatus includes a processor that, in response to receiving the message, attempts to resume a radio resource control connection.

[0008] In one embodiment, the processor detects that core network paging is due to radio access network paging failures, and, in response to being in a radio resource control inactive state, initiates transition to a radio resource control connected state by initiating a radio resource control inactivity resume procedure. In a further embodiment, in response to failing to transition to the radio resource control connected state, the processor initiates transition to a radio resource control idle state.

[0009] A method for responding to radio access network paging failures, in one embodiment, includes receiving a message including an indication of a radio access network paging failure. In various embodiments, the method includes, in response to receiving the message, attempting to resume a radio resource control connection.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] A more particular description of the embodiments briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings. Understanding that these drawings depict only some embodiments and are not therefore to be considered to be limiting of scope, the embodiments will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which:

[0011] Figure 1 is a schematic block diagram illustrating one embodiment of a wireless communication system for responding to radio access network paging failures;

[0012] Figure 2 is a schematic block diagram illustrating one embodiment of an apparatus that may be used for responding to radio access network paging failures;

[0013] Figure 3 is a schematic block diagram illustrating one embodiment of an apparatus that may be used for responding to radio access network paging failures; [0014] Figure 4 is a schematic block diagram illustrating one embodiment of communications to facilitate responding to radio access network paging failures;

[0015] Figure 5 is a schematic block diagram illustrating another embodiment of communications to facilitate responding to radio access network paging failures;

[0016] Figure 6 is a schematic flow chart diagram illustrating one embodiment of a method for responding to radio access network paging failures; and

[0017] Figure 7 is a schematic flow chart diagram illustrating another embodiment of a method for responding to radio access network paging failures.

DETAILED DESCRIPTION

[0018] As will be appreciated by one skilled in the art, aspects of the embodiments may be embodied as a system, apparatus, method, or program product. Accordingly, embodiments may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a "circuit," "module" or "system." Furthermore, embodiments may take the form of a program product embodied in one or more computer readable storage devices storing machine readable code, computer readable code, and/or program code, referred hereafter as code. The storage devices may be tangible, non-transitory, and/or non-transmission. The storage devices may not embody signals. In a certain embodiment, the storage devices only employ signals for accessing code.

[0019] Certain of the functional units described in this specification may be labeled as modules, in order to more particularly emphasize their implementation independence. For example, a module may be implemented as a hardware circuit comprising custom very-large-scale integration ("VLSI") circuits or gate arrays, off-the-shelf semiconductors such as logic chips, transistors, or other discrete components. A module may also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices or the like.

[0020] Modules may also be implemented in code and/or software for execution by various types of processors. An identified module of code may, for instance, include one or more physical or logical blocks of executable code which may, for instance, be organized as an object, procedure, or function. Nevertheless, the executables of an identified module need not be physically located together, but may include disparate instructions stored in different locations which, when joined logically together, include the module and achieve the stated purpose for the module.

[0021] Indeed, a module of code may be a single instruction, or many instructions, and may even be distributed over several different code segments, among different programs, and across several memory devices. Similarly, operational data may be identified and illustrated herein within modules, and may be embodied in any suitable form and organized within any suitable type of data structure. The operational data may be collected as a single data set, or may be distributed over different locations including over different computer readable storage devices. Where a module or portions of a module are implemented in software, the software portions are stored on one or more computer readable storage devices.

[0022] Any combination of one or more computer readable medium may be utilized. The computer readable medium may be a computer readable storage medium. The computer readable storage medium may be a storage device storing the code. The storage device may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, holographic, micromechanical, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.

[0023] More specific examples (a non-exhaustive list) of the storage device would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory ("RAM"), a read-only memory ("ROM"), an erasable programmable read-only memory ("EPROM" or Flash memory), a portable compact disc readonly memory ("CD-ROM"), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.

[0024] Code for carrying out operations for embodiments may be any number of lines and may be written in any combination of one or more programming languages including an object oriented programming language such as Python, Ruby, Java, Smalltalk, C++, or the like, and conventional procedural programming languages, such as the "C" programming language, or the like, and/or machine languages such as assembly languages. The code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network ("LAN") or a wide area network ("WAN"), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).

[0025] Reference throughout this specification to "one embodiment," "an embodiment," or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases "in one embodiment," "in an embodiment," and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment, but mean "one or more but not all embodiments" unless expressly specified otherwise. The terms "including," "comprising," "having," and variations thereof mean "including but not limited to," unless expressly specified otherwise. An enumerated listing of items does not imply that any or all of the items are mutually exclusive, unless expressly specified otherwise. The terms "a," "an," and "the" also refer to "one or more" unless expressly specified otherwise.

[0026] Furthermore, the described features, structures, or characteristics of the embodiments may be combined in any suitable manner. In the following description, numerous specific details are provided, such as examples of programming, software modules, user selections, network transactions, database queries, database structures, hardware modules, hardware circuits, hardware chips, etc., to provide a thorough understanding of embodiments. One skilled in the relevant art will recognize, however, that embodiments may be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of an embodiment.

[0027] Aspects of the embodiments are described below with reference to schematic flowchart diagrams and/or schematic block diagrams of methods, apparatuses, systems, and program products according to embodiments. It will be understood that each block of the schematic flowchart diagrams and/or schematic block diagrams, and combinations of blocks in the schematic flowchart diagrams and/or schematic block diagrams, can be implemented by code. The code may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the schematic flowchart diagrams and/or schematic block diagrams block or blocks.

[0028] The code may also be stored in a storage device that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the storage device produce an article of manufacture including instructions which implement the function/act specified in the schematic flowchart diagrams and/or schematic block diagrams block or blocks.

[0029] The code may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the code which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

[0030] The schematic flowchart diagrams and/or schematic block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of apparatuses, systems, methods and program products according to various embodiments. In this regard, each block in the schematic flowchart diagrams and/or schematic block diagrams may represent a module, segment, or portion of code, which includes one or more executable instructions of the code for implementing the specified logical function(s).

[0031] It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the Figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. Other steps and methods may be conceived that are equivalent in function, logic, or effect to one or more blocks, or portions thereof, of the illustrated Figures.

[0032] Although various arrow types and line types may be employed in the flowchart and/or block diagrams, they are understood not to limit the scope of the corresponding embodiments. Indeed, some arrows or other connectors may be used to indicate only the logical flow of the depicted embodiment. For instance, an arrow may indicate a waiting or monitoring period of unspecified duration between enumerated steps of the depicted embodiment. It will also be noted that each block of the block diagrams and/or flowchart diagrams, and combinations of blocks in the block diagrams and/or flowchart diagrams, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and code.

[0033] The description of elements in each figure may refer to elements of proceeding figures. Like numbers refer to like elements in all figures, including alternate embodiments of like elements.

[0034] Figure 1 depicts an embodiment of a wireless communication system 100 for responding to radio access network paging failures. In one embodiment, the wireless communication system 100 includes remote units 102, base units 104, and a network function 106. Even though a specific number of remote units 102, base units 104, and network functions 106 are depicted in Figure 1, one of skill in the art will recognize that any number of remote units 102, base units 104, and network functions 106 may be included in the wireless communication system 100. [0035] In one embodiment, the remote units 102 may include computing devices, such as desktop computers, laptop computers, personal digital assistants ("PDAs"), tablet computers, smart phones, smart televisions (e.g., televisions connected to the Internet), set-top boxes, game consoles, security systems (including security cameras), vehicle on-board computers, network devices (e.g., routers, switches, modems), aerial vehicles, drones, or the like. In some embodiments, the remote units 102 include wearable devices, such as smart watches, fitness bands, optical head-mounted displays, or the like. Moreover, the remote units 102 may be referred to as subscriber units, mobiles, mobile stations, users, terminals, mobile terminals, fixed terminals, subscriber stations, UE, user terminals, a device, or by other terminology used in the art. The remote units 102 may communicate directly with one or more of the base units 104 via UL communication signals.

[0036] The base units 104 may be distributed over a geographic region. In certain embodiments, a base unit 104 may also be referred to as an access point, an access terminal, a base, a base station, a Node-B, an eNB, a gNB, a Home Node-B, a relay node, a device, a core network (e.g., EPC, 5GC), an aerial server, or by any other terminology used in the art. The base units 104 are generally part of a radio access network that includes one or more controllers communicably coupled to one or more corresponding base units 104. The radio access network is generally communicably coupled to one or more core networks, which may be coupled to other networks, like the Internet and public switched telephone networks, among other networks. These and other elements of radio access and core networks are not illustrated but are well known generally by those having ordinary skill in the art. In some embodiments, the base unit 104 may include a RAN (e.g., 4G-RAN such as E-UTRA, 5G-RAN such as eLTE or NR). In certain embodiments, the network function 106 may include an MME, an AMF, a UPF, and/or an SMF.

[0037] In one implementation, the wireless communication system 100 is compliant with the 3GPP protocol, wherein the base unit 104 transmits using an OFDM modulation scheme on the DL and the remote units 102 transmit on the UL using a SC-FDMA scheme or an OFDM scheme. More generally, however, the wireless communication system 100 may implement some other open or proprietary communication protocol, for example, WiMAX, among other protocols. The present disclosure is not intended to be limited to the implementation of any particular wireless communication system architecture or protocol.

[0038] The base units 104 may serve a number of remote units 102 within a serving area, for example, a cell or a cell sector via a wireless communication link. The base units 104 transmit DL communication signals to serve the remote units 102 in the time, frequency, and/or spatial domain. [0039] In one embodiment, a network function 106 may receive an indication of radio access network paging failure. In various embodiments, the network function 106 may, in response to receiving the indication of radio access network paging failure, determine to maintain (e.g., not release) user plane connections for active protocol data unit sessions. Accordingly, a network function 106 may be used for responding to radio access network paging failures.

[0040] In one embodiment, a remote unit 102 may receive a message including an indication of a radio access network paging failure. In various embodiments, the remote unit 102 may, in response to receiving the message, attempt to resume a radio resource control connection. Accordingly, a remote unit 102 may be used for responding to radio access network paging failures.

[0041] Figure 2 depicts one embodiment of an apparatus 200 that may be used for responding to radio access network paging failures. The apparatus 200 includes one embodiment of the remote unit 102. Furthermore, the remote unit 102 may include a processor 202, a memory 204, an input device 206, a display 208, a transmitter 210, and a receiver 212. In some embodiments, the input device 206 and the display 208 are combined into a single device, such as a touchscreen. In certain embodiments, the remote unit 102 may not include any input device 206 and/or display 208. In various embodiments, the remote unit 102 may include one or more of the processor 202, the memory 204, the transmitter 210, and the receiver 212, and may not include the input device 206 and/or the display 208.

[0042] The processor 202, in one embodiment, may include any known controller capable of executing computer-readable instructions and/or capable of performing logical operations. For example, the processor 202 may be a microcontroller, a microprocessor, a central processing unit ("CPU"), a graphics processing unit ("GPU"), an auxiliary processing unit, a field programmable gate array ("FPGA"), or similar programmable controller. In some embodiments, the processor 202 executes instructions stored in the memory 204 to perform the methods and routines described herein. In various embodiments, the processor 202 may, in response to receiving a message, attempting to resume a radio resource control connection. The processor 202 is communicatively coupled to the memory 204, the input device 206, the display 208, the transmitter 210, and the receiver 212.

[0043] The memory 204, in one embodiment, is a computer readable storage medium. In some embodiments, the memory 204 includes volatile computer storage media. For example, the memory 204 may include a RAM, including dynamic RAM ("DRAM"), synchronous dynamic RAM ("SDRAM"), and/or static RAM ("SRAM"). In some embodiments, the memory 204 includes non-volatile computer storage media. For example, the memory 204 may include a hard disk drive, a flash memory, or any other suitable non-volatile computer storage device. In some embodiments, the memory 204 includes both volatile and non-volatile computer storage media. In some embodiments, the memory 204 also stores program code and related data, such as an operating system or other controller algorithms operating on the remote unit 102.

[0044] The input device 206, in one embodiment, may include any known computer input device including a touch panel, a button, a keyboard, a stylus, a microphone, or the like. In some embodiments, the input device 206 may be integrated with the display 208, for example, as a touchscreen or similar touch- sensitive display. In some embodiments, the input device 206 includes a touchscreen such that text may be input using a virtual keyboard displayed on the touchscreen and/or by handwriting on the touchscreen. In some embodiments, the input device 206 includes two or more different devices, such as a keyboard and a touch panel.

[0045] The display 208, in one embodiment, may include any known electronically controllable display or display device. The display 208 may be designed to output visual, audible, and/or haptic signals. In some embodiments, the display 208 includes an electronic display capable of outputting visual data to a user. For example, the display 208 may include, but is not limited to, an LCD display, an LED display, an OLED display, a projector, or similar display device capable of outputting images, text, or the like to a user. As another, non-limiting, example, the display 208 may include a wearable display such as a smart watch, smart glasses, a heads-up display, or the like. Further, the display 208 may be a component of a smart phone, a personal digital assistant, a television, a table computer, a notebook (laptop) computer, a personal computer, a vehicle dashboard, or the like.

[0046] In certain embodiments, the display 208 includes one or more speakers for producing sound. For example, the display 208 may produce an audible alert or notification (e.g., a beep or chime). In some embodiments, the display 208 includes one or more haptic devices for producing vibrations, motion, or other haptic feedback. In some embodiments, all or portions of the display 208 may be integrated with the input device 206. For example, the input device 206 and display 208 may form a touchscreen or similar touch-sensitive display. In other embodiments, the display 208 may be located near the input device 206.

[0047] The transmitter 210 is used to provide UL communication signals to the base unit 104 and the receiver 212 is used to receive DL communication signals from the base unit 104. In some embodiments, the receiver 212 may receive a message including an indication of a radio access network paging failure. Although only one transmitter 210 and one receiver 212 are illustrated, the remote unit 102 may have any suitable number of transmitters 210 and receivers 212. The transmitter 210 and the receiver 212 may be any suitable type of transmitters and receivers. In one embodiment, the transmitter 210 and the receiver 212 may be part of a transceiver.

[0048] Figure 3 depicts one embodiment of an apparatus 300 that may be used for responding to radio access network paging failures. The apparatus 300 includes one embodiment of the network function 106. Furthermore, the network function 106 may include a processor 302, a memory 304, an input device 306, a display 308, a transmitter 310, and a receiver 312. As may be appreciated, the processor 302, the memory 304, the input device 306, the display 308, the transmitter 310, and the receiver 312 may be substantially similar to the processor 202, the memory 204, the input device 206, the display 208, the transmitter 210, and the receiver 212 of the remote unit 102, respectively.

[0049] In some embodiments, the receiver 312 may receive an indication of radio access network paging failure. In various embodiments, the processor 302 may, in response to receiving the indication of radio access network paging failure, determine to maintain (e.g., not release) user plane connections for active protocol data unit sessions. Although only one transmitter 310 and one receiver 312 are illustrated, the base unit 104 may have any suitable number of transmitters 310 and receivers 312. The transmitter 310 and the receiver 312 may be any suitable type of transmitters and receivers. In one embodiment, the transmitter 310 and the receiver 312 may be part of a transceiver.

[0050] Figure 4 is a schematic block diagram illustrating one embodiment of communications 400 to facilitate responding to radio access network paging failures. The communications 400 include communication between a UE 402, a RAN 404, an AMF 406, a UPF 408, and an SMF 410. However, in other embodiments, the communications may be between different devices.

[0051] In certain embodiments, a first communication 412 between the UE 402 and the RAN 404 may include one or more messages used to release a signaling path over an access network. In some embodiments, a second communication 414 transmitted from the RAN 404 to the AMF 406 may include an access network (e.g., N2) context release request. In various embodiments, a third communication 416 transmitted from the AMF 406 to the SMF 410 may include a PDU session deactivation request (e.g., an Ni l PDU session deactivation request).

[0052] In certain embodiments, a fourth communication 418 transmitted from the SMF

410 to the UPF 408 may include a session modification request (e.g., an N4 session modification request). In some embodiments, a fifth communication 420 transmitted from the UPF 408 to the SMF 410 may include a session modification response (e.g., an N4 session modification response). In various embodiments, a sixth communication 422 transmitted from the SMF 410 to the AMF 406 may include a PDU session deactivation response (e.g., an Ni l PDU session deactivation response).

[0053] In certain embodiments, a seventh communication 424 transmitted from the AMF 406 to the RAN 404 may include an access network (e.g., N2) context release command. In some embodiments, an eighth communication 426 between the UE 402 and the RAN 404 may include one or more messages used to release a signaling path over the access network. In various embodiments, a ninth communication 428 transmitted from the RAN 404 to the AMF 406 may include an access network (e.g., N2) context release complete message.

[0054] Figure 5 is a schematic block diagram illustrating another embodiment of communications 500 to facilitate responding to radio access network paging failures. The communications 500 include communication between a UE 502, a source RAN 504, a target RAN 506, an AMF 508, a UPF 510, and an SMF 512. However, in other embodiments, the communications may be between different devices.

[0055] In various embodiments, a RAN paging failure 514 may be detected by the source RAN 504. In certain embodiments, if the RAN paging failure 514 happens in the source RAN 504, the source RAN 504 may decide to initiate communication with the AMF 508.

[0056] In certain embodiments, a first communication 516 transmitted from the source RAN 504 to the AMF 508 may include a message used to indicate a RAN paging failure. In one embodiment, the message may be a notification message; while, in another embodiment, the message may include an access network (e.g., N2) UE context release request that initiates a context release procedure. In various embodiments, the first communication 516 may include a RAN paging failure indicator.

[0057] In some embodiments, the AMF 508 may determine 518 whether to page the UE 502. In response to determining 518 to page the UE 502, the AMF 508 may move the UE 502 to an idle state (e.g., CM_IDLE) and keep PDU sessions active until the AMF 508 receives a response from the UE 502 (e.g., determine to maintain (not release) user plane connections for active PDU sessions). In various embodiments, the AMF 508 may keep the UE 502 in a connected state (e.g. CM_CONNECTED) until a pre-defined period of time or until the AMF 508 receives a response from the source RAN 504. If the AMF 508 does not receive a response or the pre-defined period of time expires the AMF 506 may move the UE 502 to an idle state and releases the respective PDU sessions.

[0058] In some embodiments, a second communication 520 transmitted from the AMF 508 to the UE 502 may initiate a core network ("CN") paging procedure. In various embodiments, the AMF 508 may include a reason code indicating that CN paging is initiated due to RAN paging failure.

[0059] In certain embodiments, the UE 502 detects 522 paging. In some embodiments, the UE 502 detects 522 that the CN paging is due to RAN paging failures. In response to detecting 522 that the CN paging is due to RAN paging failures, if the UE 502 is in an inactive state (e.g., RRCJNACTIVE state) or a CM_CONNECTED state, the UE 502 tries to resume an RRC connection. If the RRC resume fails, the UE 502 may move to an idle state (e.g., CM_IDLE), release its access stratum ("AS") context, and send a service request. Moreover, in response to detecting 522 that the CN paging is due to RAN paging failures, if the UE 502 is in the idle state (e.g., CM_IDLE state), the UE 502 may release its access stratum ("AS") context, and send a service request.

[0060] In various embodiments, a third communication 524 transmitted from the UE 502 to the target RAN 506 may include an RRC resume message in which the UE 502 indicates that the RRC connection is resumed due to CN paging.

[0061] In certain embodiments, a fourth communication 526 transmitted from the target

RAN 506 to the source RAN 504 may be used to retrieve the UE 502 context from the source RAN 504.

[0062] In some embodiments, a fifth communication 528 transmitted from the source RAN

504 to the target RAN 506 may be used to transmit the UE 502 context to the target RAN 506.

[0063] In various embodiments, a sixth communication 530 between the source RAN 504 and the target RAN 506 includes one or more messages in which the source RAN 504 provides buffered data to the target RAN 506.

[0064] In certain embodiments, a seventh communication 532 transmitted from the target

RAN 506 to the AMF 508 may include a path switch request. In various embodiments, the path switch request includes an indication that the UE 502 due to CN paging.

[0065] In some embodiments, the AMF 508 determines 534 whether to change the state of the UE 502. In various embodiments, if the RRC connection was successfully resumed by the UE

502, the AMF 508 may move the UE 502 to the CM_CONNECTED state and keep the PDU sessions active and/or may update 536 the PDU sessions.

[0066] In some embodiments, the AMF 508 determines 534 whether to keep the state of the UE 502. In various embodiments, if the RRC connection was successfully resumed by the UE

502, the AMF 508 may keep the UE 502 in the CM_CONNECTED state and keep the PDU sessions active and/or may update 536 the PDU sessions. [0067] In some embodiments, an eighth communication 538 transmitted from the AMF 508 to the source RAN 504 may include a UE context release command. In certain embodiments, instead of transmitting the eighth communication 538, the UE context may be released via an Xn interface. In various embodiments, a ninth communication 540 transmitted from the source RAN 504 to the AMF 508 may include a UE context release complete message.

[0068] Figure 6 is a schematic flow chart diagram illustrating one embodiment of a method 600 for responding to radio access network paging failures. In some embodiments, the method 600 is performed by an apparatus, such as the network function 106 (e.g., AMF). In certain embodiments, the method 600 may be performed by a processor executing program code, for example, a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like.

[0069] The method 600 may include receiving 602 an indication of radio access network paging failure. In various embodiments, the method 600 includes, in response to receiving the indication of radio access network paging failure, determining 604 to maintain (e.g., not release) user plane connections for active protocol data unit sessions.

[0070] In one embodiment, the method 600 includes transmitting a message to a remote unit 102 including an indication of the radio access network paging failure in response to the receiver receiving the indication of radio access network paging failure. In a further embodiment, the method 600 includes, in response to transmitting the message to the remote unit 102 including the indication of the radio access network paging failure, receiving an acknowledgement of the message transmitted to the remote unit 102. In certain embodiments, the acknowledgment is received from a target radio access network, and the target radio access network transmits the acknowledgment in response to receiving a resume message from the remote unit. In various embodiments, the indication of radio access network paging failure is received as part of an access network context release request. In some embodiments, the indication of radio access network paging failure is received as part of a notification that radio access network paging failed. In some embodiments, the method 600 includes determining a state of a remote unit based on whether a radio resource control connection was resumed by the remote unit.

[0071] Figure 7 is a schematic flow chart diagram illustrating another embodiment of a method 700 for responding to radio access network paging failures. In some embodiments, the method 700 is performed by an apparatus, such as the remote unit 102. In certain embodiments, the method 700 may be performed by a processor executing program code, for example, a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like. [0072] The method 700 may include receiving 702 a message including an indication of a radio access network paging failure. In various embodiments, the method 700 includes, in response to receiving the message, attempting 704 to resume a radio resource control connection.

[0073] In one embodiment, the method 700 includes detecting that core network paging is due to radio access network paging failures, and, in response to being in a radio resource control inactive state, initiating transition to a radio resource control connected state by initiating a radio resource control inactivity resume procedure. In a further embodiment, the method 700 includes, in response to failing to transition to the radio resource control connected state, initiating transition to a radio resource control idle state.

[0074] Embodiments may be practiced in other specific forms. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims

A method comprising: receiving an indication of radio access network paging failure; and

in response to receiving the indication of radio access network paging failure,

determining to maintain user plane connections for active protocol data unit sessions.

The method of claim 1, further comprising transmitting a message to a remote unit comprising an indication of the radio access network paging failure in response to receiving the indication of radio access network paging failure.

The method of claim 2, wherein, in response to transmitting the message to the remote unit comprising the indication of the radio access network paging failure, receiving an acknowledgement of the message transmitted to the remote unit.

The method of claim 3, wherein the acknowledgment is received from a target radio access network, and the target radio access network transmits the acknowledgment in response to receiving a resume message from the remote unit.

The method of claim 1, wherein the indication of radio access network paging failure is received as part of an access network context release request.

The method of claim 1, wherein the indication of radio access network paging failure is received as part of a notification that radio access network paging failed.

The method of claim 1, further comprising determining a state of a remote unit based on whether a radio resource control connection was resumed by the remote unit.

8. An apparatus comprising: a receiver that receives an indication of radio access network paging failure; and a processor that, in response to receiving the indication of radio access network paging failure, determines to maintain user plane connections for active protocol data unit sessions.

9. The apparatus of claim 8, further comprising a transmitter that transmits a message to a remote unit comprising an indication of the radio access network paging failure in response to the receiver receiving the indication of radio access network paging failure.

10. The apparatus of claim 9, wherein, in response to the transmitter transmitting the message to the remote unit comprising the indication of the radio access network paging failure, the receiver receives an acknowledgement of the message transmitted to the remote unit.

11. The apparatus of claim 10, wherein the acknowledgment is received from a target radio access network, and the target radio access network transmits the acknowledgment in response to receiving a resume message from the remote unit.

12. The apparatus of claim 8, wherein the indication of radio access network paging failure is received as part of an access network context release request.

13. The apparatus of claim 8, wherein the indication of radio access network paging failure is received as part of a notification that radio access network paging failed.

14. The method of claim 8, wherein the processor determines a state of a remote unit based on whether a radio resource control connection was resumed by the remote unit.

15. A method comprising: receiving a message comprising an indication of a radio access network paging failure; and

in response to receiving the message, attempting to resume a radio resource control

connection.

16. The method of claim 15, further comprising detecting that core network paging is due to radio access network paging failures, and, in response to being in a radio resource control inactive state, transitioning to a radio resource control connected state by initiating a radio resource control inactivity resume procedure.

17. The method of claim 16, wherein, in response to failing to transition to the radio resource control connected state, transitioning to a radio resource control idle state.

18. An apparatus comprising: a receiver that receives a message comprising an indication of a radio access network paging failure; and

a processor that, in response to receiving the message, attempts to resume a radio

resource control connection.

19. The apparatus of claim 18, wherein the processor detects that core network paging is due to radio access network paging failures, and, in response to being in a radio resource control inactive state, initiates transition to a radio resource control connected state by initiating a radio resource control inactivity resume procedure.

20. The apparatus of claim 19, wherein, in response to failing to transition to the radio

resource control connected state, the processor initiates transition to a radio resource control idle state.