Device, method and computer program for connection management

Abstract

A device, comprising: at least one processor; and at least one memory, the at least one memory comprising computer program code; the at least one memory and the computer program code are configured to, together with the at least one processor, cause the device to at least: receive (602) a fallback indication from a radio resource control layer; invoke (604) a service request process; and set (606, 608) at least one of a service type information element and an uplink data status information element in a service request message.

Description

Technical Field

[0001] The present disclosure relates to an apparatus, method and computer program for invoking a service request procedure. Background Art

[0002] A communication system may be viewed as a facility for enabling communication sessions between two or more entities, such as user terminals, base stations / access points, and / or other nodes, by providing a carrier wave between the various entities involved in the communication path. A communication system may be provided, for example, by means of a communication network and one or more compatible communication devices. A communication session may include, for example, the communication of data for carrying communications, such as voice, electronic mail (email), text messages, multimedia and / or content data, etc. Non-limiting examples of the services provided include two-way or multi-way calls, data communications or multimedia services, and access to data network systems, such as the Internet. In a wireless communication system, at least a portion of a communication session between at least two stations occurs over a wireless link.

[0003] A user can access the communication system with the aid of an appropriate communication device or terminal. The user's communication device is often referred to as a user equipment (UE) or user device. The communication device is equipped with appropriate signal receiving and transmitting equipment for implementing communication (e.g., implementing access to the communication network and / or direct communication with other users). The communication device can access a carrier provided by a station or access point and transmit and / or receive communications on the carrier.

[0004] The communication system and associated devices typically operate according to a given standard or specification, which sets out what the various entities associated with the system are permitted to do and how it should be achieved. The communication protocols and / or parameters that should be used for the connection are also typically defined. An example of a communication system is UTRAN (3G radio). Another example of an architecture is called the Long Term Evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio access technology. Another example communication system is the so-called 5G radio or New Radio (NR) access technology. Summary of the invention

[0005] According to one aspect, a device is provided, comprising at least one processor and at least one memory, the at least one memory comprising computer code for one or more programs, the at least one memory and the computer code being configured to, together with the at least one processor, cause the device to at least: receive a fallback indication from a radio resource control layer; invoke a service request process; and set at least one of a service type information element and an uplink data status information element in a service request message.

[0006] The at least one memory and the computer program code may be configured to, together with the at least one processor, cause the device to at least: determine that (i) the user equipment has no pending non-access layer process, (j) the user equipment has a pending service request process due to a reason different from a predetermined reason, (k) the user equipment has a pending service request process due to the predetermined reason, or (l) the user equipment has a pending non-access layer process other than a service request process; and invoke the service request process based on the determination.

[0007] The at least one memory and the computer program code may be configured to, with the at least one processor, cause the apparatus to at least: determine (i) that the user equipment has pending uplink user data and no pending non-access stratum procedures.

[0008] The at least one memory and the computer program code may be configured to, with the at least one processor, cause the apparatus to at least: determine (j) that the user equipment has a pending service request procedure invoked due to non-emergency service fallback.

[0009] The at least one memory and the computer program code may be configured to, with the at least one processor, cause the apparatus to at least: determine (k) that the user equipment has a pending service request procedure invoked due to emergency service fallback.

[0010] The at least one memory and the computer program code may be configured to, together with the at least one processor, cause the device to at least: determine (1) that the user equipment has a pending non-access layer procedure other than a registration procedure, a service request procedure, or a deregistration procedure.

[0011] The user equipment may be in connected mode.

[0012] The user equipment may be in a connected inactive mode.

[0013] The at least one memory and the computer program code may be configured to, with the at least one processor, cause the apparatus to at least: set the service type information element in the service request message in dependence on the determination.

[0014] The at least one memory and the computer program code may be configured to, together with the at least one processor, cause the device to at least: when (i) the user equipment has no pending non-access layer procedure, set the service type information element in the service request message to 'high priority access', 'emergency service' or 'data'.

[0015] The at least one memory and the computer program code may be configured to, together with the at least one processor, cause the apparatus to at least: when (j) the user equipment has a pending service request process due to a reason different from a predetermined reason, set the service type information element in the service request message to 'mobile terminated service', 'high priority access', 'emergency service' or 'data'.

[0016] The at least one memory and the computer program code may be configured to, together with the at least one processor, cause the apparatus to at least: when (k) the user equipment has a pending service request process due to a predetermined reason, set the service type information element in the service request message to 'emergency service fallback'.

[0017] The at least one memory and the computer program code may be configured to, together with the at least one processor, cause the device to at least: when (l) the user equipment has a pending non-access layer procedure other than a service request procedure, set the service type information element in the service request message to 'high priority access', 'emergency service' or 'signaling'.

[0018] The at least one memory and the computer program code may be configured to, with the at least one processor, cause the apparatus to at least: set the uplink data state information element in the service request message based on the determination.

[0019] The at least one memory and the computer program code may be configured to, together with the at least one processor, cause the device to at least: when (i) the user equipment has no pending non-access layer procedure, set the uplink data status information element in the service request message to indicate a packet data unit session for which user plane resources were active prior to invoking the service request procedure.

[0020] The at least one memory and the computer program code may be configured to, together with the at least one processor, cause the device to at least: when (j) the user equipment has a pending service request process due to a reason different from a predetermined reason, set the uplink data status information element in the service request message to indicate a packet data unit session for which user plane resources were active before invoking the service request process and / or that user plane resources were inactive before receiving the fallback indication and the user equipment has a pending packet data unit session for which user data is to be sent over a cellular network.

[0021] The at least one memory and the computer program code may be configured to, together with the at least one processor, cause the device to at least: when (l) the user equipment in connected mode has a pending non-access layer procedure other than a service request procedure, set the uplink data status information element in the service request message to indicate a packet data unit session for which user plane resources were active before invoking the service request procedure.

[0022] The at least one memory and the computer program code may be configured to, together with the at least one processor, cause the device to at least: when (l) the user equipment in the connected inactive mode has a pending non-access layer process other than a service request process, set the uplink data status information element in the service request message to indicate an always-online packet data unit session.

[0023] At least one of the receiving, the determining, the calling, and the setting may be performed at a non-access layer layer.

[0024] According to one aspect, a device is provided, comprising circuitry configured to: receive a fallback indication from a radio resource control layer; invoke a service request procedure; and set at least one of a service type information element and an uplink data status information element in a service request message.

[0025] The circuit may be configured to: determine that (i) the user equipment has no pending non-access layer process, (j) the user equipment has a pending service request process due to a reason different from a predetermined reason, (k) the user equipment has a pending service request process due to the predetermined reason, or (l) the user equipment has a pending non-access layer process other than a service request process; and invoke the service request process based on the determination.

[0026] The circuitry may be configured to determine that (i) the user equipment has pending uplink user data and no pending non-access stratum procedures.

[0027] The circuitry may be configured to determine (j) that the user equipment has a pending service request procedure invoked due to non-emergency service fallback.

[0028] The circuitry may be configured to determine (k) that the user equipment has a pending service request procedure invoked due to emergency service fallback.

[0029] The circuit may be configured such that: (l) the user equipment has a pending non-access layer procedure other than a registration procedure, a service request procedure or a deregistration procedure.

[0030] The user equipment may be in connected mode.

[0031] The user equipment may be in a connected inactive mode.

[0032] The circuitry may be configured to set the service type information element in the service request message dependent on the determination.

[0033] The circuit may be configured to: when (i) the user equipment has no pending non-access stratum procedure, set the service type information element in the service request message to 'high priority access', 'emergency service' or 'data'.

[0034] The circuit may be configured to: when (j) the user equipment has a pending service request process due to a reason different from a predetermined reason, set the service type information element in the service request message to 'mobile terminated service', 'high priority access', 'emergency service' or 'data'.

[0035] The circuit may be configured to: when (k) the user equipment has a pending service request procedure due to a predetermined reason, set the service type information element in the service request message to 'emergency service fallback'.

[0036] The circuit may be configured to: when (l) the user equipment has a pending non-access stratum procedure other than a service request procedure, set the service type information element in the service request message to 'high priority access', 'emergency service' or 'signalling'.

[0037] The circuitry may be configured to set the uplink data status information element in the service request message based on the determination.

[0038] The circuit may be configured to: when (i) the user equipment has no pending non-access layer procedure, set the uplink data status information element in the service request message to indicate a packet data unit session for which user plane resources were active before invoking the service request procedure.

[0039] The circuit may be configured to: when (j) the user equipment has a pending service request procedure due to a reason different from the predetermined reason, set the uplink data status information element in the service request message to indicate a packet data unit session for which user plane resources were active before invoking the service request procedure and / or a packet data unit session for which user plane resources were inactive before receiving the fallback indication and the user equipment has a pending user data to be sent over a cellular network.

[0040] The circuit may be configured to: when (l) the user equipment in connected mode has a pending non-access layer procedure other than a service request procedure, set the uplink data status information element in the service request message to indicate a packet data unit session for which user plane resources were active before invoking the service request procedure.

[0041] The circuit may be configured to: when (l) the user equipment in connected inactive mode has a pending non-access layer process other than a service request process, set the uplink data status information element in the service request message to indicate an always-on packet data unit session.

[0042] At least one of the receiving, the determining, the calling, and the setting may be performed at a non-access layer layer.

[0043] According to an aspect, a method is provided, the method comprising: receiving a fallback indication from a radio resource control layer; invoking a service request procedure; and setting at least one of a service type information element and an uplink data status information element in a service request message.

[0044] The method may include: determining that (i) the user equipment has no pending non-access layer process, (j) the user equipment has a pending service request process due to a reason different from a predetermined reason, (k) the user equipment has a pending service request process due to the predetermined reason, or (l) the user equipment has a pending non-access layer process other than a service request process; and invoking the service request process based on the determination.

[0045] The method may include determining that (i) the user equipment has pending uplink user data and no pending non-access stratum procedures.

[0046] The method may include determining (j) that the user equipment has a pending service request procedure invoked due to non-emergency service fallback.

[0047] The method may include determining (k) that the user equipment has a pending service request procedure invoked due to emergency service fallback.

[0048] The method may include determining (1) that the user equipment has a pending non-access stratum procedure other than a registration procedure, a service request procedure, or a deregistration procedure.

[0049] The user equipment may be in connected mode.

[0050] The user equipment may be in a connected inactive mode.

[0051] The method may comprise setting the service type information element in the service request message dependent on the determining.

[0052] The method may include: when (i) the user equipment has no pending non-access stratum procedure, setting the service type information element in the service request message to 'high priority access', 'emergency service' or 'data'.

[0053] The method may include: when (j) the user equipment has a pending service request process due to a reason different from the predetermined reason, setting the service type information element in the service request message to 'mobile terminated service', 'high priority access', 'emergency service' or 'data'.

[0054] The method may include: when (k) the user equipment has a pending service request procedure due to a predetermined reason, setting the service type information element in the service request message to 'emergency service fallback'.

[0055] The method may include: when (l) the user equipment has a pending non-access stratum procedure other than a service request procedure, setting the service type information element in the service request message to 'high priority access', 'emergency service' or 'signaling'.

[0056] The method may comprise setting the uplink data status information element in the service request message based on the determination.

[0057] The method may include: when (i) the user equipment has no pending non-access layer procedure, setting the uplink data status information element in the service request message to indicate a packet data unit session for which user plane resources were active before invoking the service request procedure.

[0058] The method may include: when (j) the user equipment has a pending service request procedure due to a reason different from a predetermined reason, setting the uplink data status information element in the service request message to indicate a packet data unit session for which user plane resources were active before invoking the service request procedure and / or a packet data unit session for which user plane resources were inactive before receiving the fallback indication and the user equipment has a pending user data to be sent over a cellular network.

[0059] The method may include: when (l) the user equipment in connected mode has a pending non-access layer procedure other than a service request procedure, setting the uplink data status information element in the service request message to indicate a packet data unit session for which user plane resources were active before invoking the service request procedure.

[0060] The method may include: when (l) the user equipment in the connected inactive mode has a pending non-access layer process other than a service request process, setting the uplink data status information element in the service request message to indicate an always-on packet data unit session.

[0061] At least one of the receiving, the determining, the calling, and the setting may be performed at a non-access layer layer.

[0062] According to one aspect, a computer program comprising computer executable code is provided, which, when executed on at least one processor, is configured to: receive a fallback indication from a radio resource control layer; invoke a service request procedure; and set at least one of a service type information element and an uplink data status information element in a service request message.

[0063] The computer program includes computer executable code, which, when executed on at least one processor, can be configured to: determine that (i) the user equipment has no pending non-access layer process, (j) the user equipment has a pending service request process due to a reason different from a predetermined reason, (k) the user equipment has a pending service request process due to the predetermined reason, or (l) the user equipment has a pending non-access layer process other than a service request process; and invoke the service request process based on the determination.

[0064] The computer program includes computer executable code which, when executed on at least one processor, may be configured to: determine that (i) the user equipment has pending uplink user data and no pending non-access stratum procedures.

[0065] The computer program includes computer executable code which, when executed on at least one processor, may be configured to: determine (j) that the user equipment has a pending service request process invoked due to non-emergency service fallback.

[0066] The computer program includes computer executable code which, when executed on at least one processor, may be configured to: determine (k) that the user equipment has a pending service request procedure invoked due to emergency service fallback.

[0067] The computer program includes computer executable code, which, when executed on at least one processor, can be configured to: determine (1) that the user equipment has a pending non-access layer procedure other than a registration procedure, a service request procedure, or a deregistration procedure.

[0068] The user equipment may be in connected mode.

[0069] The user equipment may be in a connected inactive mode.

[0070] The computer program comprises computer executable code which, when executed on at least one processor, may be configured to: set the service type information element in the service request message in dependence on the determination.

[0071] The computer program includes computer executable code, which, when executed on at least one processor, can be configured to: when (i) the user equipment has no pending non-access layer process, set the service type information element in the service request message to 'high priority access', 'emergency service' or 'data'.

[0072] The computer program includes computer executable code, which when executed on at least one processor can be configured to: when (j) the user equipment has a pending service request process due to a reason different from the predetermined reason, set the service type information element in the service request message to 'mobile terminated service', 'high priority access', 'emergency service' or 'data'.

[0073] The computer program includes computer executable code, which when executed on at least one processor can be configured to: when (k) the user equipment has a pending service request process due to a predetermined reason, set the service type information element in the service request message to 'emergency service fallback'.

[0074] The computer program includes computer executable code, which, when executed on at least one processor, can be configured to: when (l) the user equipment has a pending non-access layer procedure other than a service request procedure, set the service type information element in the service request message to 'high priority access', 'emergency service' or 'signaling'.

[0075] The computer program comprises computer executable code which, when executed on at least one processor, may be configured to: set the uplink data state information element in the service request message based on the determination.

[0076] The computer program includes computer executable code, which when executed on at least one processor can be configured to: when (i) the user equipment has no pending non-access layer procedure, set the uplink data status information element in the service request message to indicate a packet data unit session for which user plane resources were active before invoking the service request procedure.

[0077] The computer program includes computer executable code, which when executed on at least one processor can be configured to: when (j) the user equipment has a pending service request process due to a reason different from the predetermined reason, set the uplink data status information element in the service request message to indicate a packet data unit session for which user plane resources were active before invoking the service request process and / or a packet data unit session for which user plane resources were inactive before receiving the fallback indication and the user equipment has a pending user data to be sent over a cellular network.

[0078] The computer program includes computer executable code, which when executed on at least one processor can be configured to: when (l) the user equipment in connected mode has a pending non-access layer procedure other than a service request procedure, set the uplink data status information element in the service request message to indicate a packet data unit session for which user plane resources were active before invoking the service request procedure.

[0079] The computer program includes computer executable code, which, when executed on at least one processor, can be configured to: when (l) the user equipment in connected inactive mode has a pending non-access layer process other than a service request process, set the uplink data status information element in the service request message to indicate an always-online packet data unit session.

[0080] At least one of the receiving, the determining, the calling, and the setting may be performed at a non-access layer layer.

[0081] According to one aspect, a computer-readable medium is provided, the computer-readable medium including program instructions stored thereon for executing at least one of the above methods.

[0082] According to one aspect, a non-transitory computer-readable medium is provided, the non-transitory computer-readable medium including program instructions stored thereon for executing at least one of the above methods.

[0083] According to an aspect, a non-volatile tangible memory medium is provided, the non-volatile tangible memory medium comprising program instructions stored thereon for executing at least one of the above methods.

[0084] In the above, many different aspects have been described. It should be appreciated that further aspects may be provided by combining any two or more of the above aspects.

[0085] Various other aspects are also described in the following detailed description and appended claims.

[0086] abbreviation:

[0087] AS: Access layer

[0088] AMF Access Management Function

[0089] CN: Core Network

[0090] DNN: Data Network Name

[0091] DRX: Discontinuous Reception

[0092] EMM: EPS Mobility Management

[0093] ENB: Evolved Node B

[0094] EPS: Evolved Packet System

[0095] EPC: Evolved Packet Core

[0096] ESFB: Emergency Service Fallback

[0097] E-UTRA: Evolved Universal Terrestrial Radio Access

[0098] GNB: Next Generation Node B

[0099] GSM: Global System for Mobile Communications

[0100] GUTI: Globally unique temporary UE identifier

[0101] HO: Handover

[0102] ID: Identifier

[0103] IE: Information Element

[0104] LTE: Long Term Evolution

[0105] LADN: Local Area Data Network

[0106] NB: Node B

[0107] NG: Next Generation

[0108] MAC: Media Access Control

[0109] MICO: Mobile initiated connections only

[0110] MS: Mobile Station

[0111] MTC: Machine Type Communication

[0112] NAS: Non-Access Layer

[0113] NSSAI: Network Slice Selection Assistance Information

[0114] PDA: Personal Digital Assistant

[0115] PDCP: Packet Data Convergence Protocol

[0116] PDU: Packet Data Unit

[0117] PDN: Packet Data Network

[0118] PHY: Physical

[0119] PLMN: Public Land Mobile Network

[0120] RAM: Random Access Memory

[0121] RAN: Radio Access Network

[0122] RAT: Radio Access Technology

[0123] RCU: Radio Control Unit

[0124] RLC: Radio Link Control

[0125] ROM: Read Only Memory

[0126] RRC: Radio Resource Control

[0127] SMS: Short Message Service

[0128] SMF: Session Management Function

[0129] S-NSSAI: Single Network Slice Selection Assistance Information

[0130] TAI: Tracking Area Identifier

[0131] TMSI: Temporary Mobile Subscriber Identity

[0132] UE: User Equipment

[0133] UL: Uplink

[0134] UMTS: Universal Mobile Telecommunications System

[0135] UPSI: User Equipment Policy Section Identifier

[0136] USB: Universal Serial Bus

[0137] 3G: Third Generation

[0138] 3GPP: Third Generation Partnership Project

[0139] 4G: Fourth Generation

[0140] 5G: Fifth Generation

[0141] 5GS: 5G System

[0142] 5GMM: 5G System Mobility Management BRIEF DESCRIPTION OF THE DRAWINGS

[0143] Embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0144] Figure 1 A schematic diagram of a communication system is shown;

[0145] Figure 2 shows a schematic diagram of a control device;

[0146] Figure 3 A schematic diagram of a user equipment is shown;

[0147] Figure 4 A schematic diagram showing a control plane stack of a user equipment, a base station and a core network in a 5G system is shown;

[0148] Figure 5 A schematic diagram showing a mobility management mode of a user equipment in a 5G system is shown;

[0149] Figure 6 A schematic diagram showing a diagram of a method of performing a service request process;

[0150] Figure 7 A schematic diagram of a diagram showing a method of setting an uplink data status information element in a "SERVICE REQUEST" message when condition i) is met;

[0151] Figure 8 A schematic diagram showing a method of setting a service type information element in a "service request" message when condition i) is met;

[0152] Fig. 9 A schematic diagram showing a method of setting the uplink data status information element in the "Service Request" message when situation j) is met;

[0153] Fig.10 A schematic diagram showing a method of setting the service type information element in the "Service Request" message when situation j) is met;

[0154] Fig.11 A schematic diagram showing a method of setting the service type information element in the "Service Request" message when condition k) is met;

[0155] Fig.12 A schematic diagram showing a method of setting an uplink data status information element in a "Service Request" message when condition 1) is met;

[0156] Fig.13 A schematic diagram showing a method of setting a service type information element in a "service request" message when condition l) is met;

[0157] Fig.14 A schematic diagram of a non-volatile memory medium storing instructions that, when executed by a processor, allow the processor to perform Figures 6 to 13 One or more of the steps of any of the methods of .

[0158] Fig.15 A schematic diagram showing a method of performing a registration request procedure according to the proposed modification to 3GPP TS24.501;

[0159] Fig.16 A schematic diagram of a diagram showing a method of performing a service request procedure according to the proposed modification to 3GPP TS 24.501. DETAILED DESCRIPTION

[0160] In the following, certain embodiments are explained with reference to a mobile communication device capable of communicating via a wireless cellular system and a mobile communication system serving such a mobile communication device. Figures 1 to 5 Certain general principles of wireless communication systems, their access systems and mobile communication devices are briefly explained to help understand the underlying technology of the described examples.

[0161] Figure 1 An example of a wireless communication system 100 is shown. The wireless communication system 100 includes wireless communication devices 102, 104, 105. Wireless access is provided to the mobile communication devices 102, 104, 105 via at least one base station 106 and 107 or similar wireless transmission and / or reception nodes or points. The base station may be an evolved Node B (eNB), a next generation Node B (gNB), or other. The base stations 106 and 107 are typically controlled by at least one appropriate control device. The controller device may be part of the base stations 106 and 107.

[0162] The base stations 106 and 107 are connected to a wider communications network 113 via a gateway 112. A further gateway function may be provided to connect to another network.

[0163] Base stations 116, 118, and 120 associated with smaller cells may also be connected to network 113, for example, through separate gateway functions and / or via macro-level stations. Base stations 116, 118, and 120 may be pico- or femto-level base stations, or the like. In an example, base stations 116 and 118 are connected via gateway 111, while base station 120 is connected via base station 106. In some embodiments, smaller base stations 116, 118, and 120 may not be provided.

[0164] Figure 2 An example of a control device 200 for a node is shown, the control device being integrated with, coupled to, and / or otherwise controlling a base station, such as a base station Figure 1 The base station 106, 107, 116, 118 or 120 shown. The control device 200 may be arranged to allow communication between the user equipment and the core network. For this purpose, the control device includes at least one random access memory (RAM) 211a and at least one read-only memory (ROM) 211b, at least one processor 212, 213 and an input / output interface 214. At least one processor 212, 213 is coupled to the RAM 211a and the ROM 211b. Via the interface, the control device 200 may be coupled to other related components of the base station. At least one processor 212, 213 may be configured to execute appropriate software code 215. The software code 215 may be stored in the ROM 211b. It should be understood that similar components may be provided in a control device disposed elsewhere in the network system (e.g., in a core network (CN) entity). The control device 200 may be interconnected with other control entities. The control device 200 and functions may be distributed between multiple control units. In some embodiments, each base station may include a control device. In an alternative embodiment, two or more base stations may share control equipment.

[0165] The base stations and associated controllers may communicate with each other via fixed line connections and / or via a radio interface. Logical connections between base stations may be provided, for example, via an X2 or similar interface. This interface may be used, for example, to coordinate the operation of the base stations and to perform reselection or handover operations.

[0166] Figure 3 A user equipment or wireless communication device 300 (such as Figure 1102, 104 or 105). The wireless communication device 300 may be provided by any device capable of sending and receiving radio signals. Non-limiting examples include a mobile station (MS) or mobile device (such as a mobile phone or so-called "smart phone"), a computer with a wireless interface card or other wireless interface facilities (e.g., a USB dongle), a personal data assistant (PDA) or a tablet computer with wireless communication capabilities, a machine type communication (MTC) device, an IoT type communication device, or any combination of these devices, etc. The device may provide communication, such as data for carrying the communication. The communication may be one or more of voice, electronic mail (email), text message, multimedia, data, machine data, etc.

[0167] The apparatus 300 may receive signals over the air or radio interface 307 via suitable equipment for receiving, and may transmit signals via suitable equipment for transmitting radio signals. Figure 3 In FIG. 3 , a transceiver device is schematically indicated by block 306. The transceiver device 306 may be provided, for example, by means of a radio part and an associated antenna arrangement. The antenna arrangement may be arranged internally or externally to the mobile device.

[0168] The wireless communication device 300 may be provided with at least one processor 301, at least one memory ROM 302a, at least one RAM 302b, and possibly other components 303, for use in the software and hardware assisted execution of the tasks it is designed to perform, including controlling access to and communication with access systems and other communication devices. The at least one processor 301 is coupled to the RAM 211a and the ROM 211b. The at least one processor 301 may be configured, for example, to execute appropriate software code 308 to perform Figures 6 to 15 The software code 308 may be stored in the ROM 211b.

[0169] The processor, storage device and other related control equipment may be provided on an appropriate circuit board and / or in a chipset. This feature is indicated by reference numeral 304. The device may optionally have a user interface, such as a keypad 305, a touch-sensitive screen or touchpad, a combination thereof, etc. Optionally, one or more of a display, a speaker and a microphone may be provided depending on the type of device.

[0170] Figure 4 A schematic diagram of the control plane stack of UE, gNB and CN in a 5G system is shown.

[0171] The UE includes a physical (PHY) layer, a medium access control (MAC) layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, a radio resource control (RRC) layer, and a non-access layer (NAS) layer. The gNB includes a PHY layer, a MAC layer, an RLC layer, a PDCP layer, and an RRC layer. The CN includes a NAS layer.

[0172] Each layer of the UE, gNB, and CN may include one of multiple functions that perform one or more processes.

[0173] Figure 5 A schematic diagram of a state machine of a UE in a 5G system is shown. The state machine includes various 5G system mobility management (5GMM) modes, such as an idle mode (e.g., a "5GMM idle" mode), a connected mode (e.g., a "5GMM connected" mode), and a connected inactive mode (e.g., a "5GMM connected" mode with an RRC inactive indication).

[0174] Idle mode and connected mode are available via 3GPP access or non-3GPP access. Connected inactive mode is only available via 3GPP access.

[0175] It will be understood that "3GPP access" may refer to cellular access, such as Long Term Evolution (LTE) access or New Radio (NR) access. In contrast, non-3GPP access may refer to non-cellular access, such as WiFi access.

[0176] After power on, the UE may enter idle mode. The UE may also enter idle mode from connected mode or connected inactive mode.

[0177] In connected mode, the UE can be connected to the 5G radio access network (RAN) and the 5G core network (CN). The UE can also enter connected mode from idle mode or connected inactive mode.

[0178] The mode of the UE may be determined based on the presence of a NAS signaling connection (e.g., AMF) between the UE and the CN. When there is a NAS signaling connection, the UE may be in connected mode. When there is a NAS signaling connection but the underlying access layer connection is suspended, the UE may be in connected inactive mode; otherwise, in "5GMM idle" mode.

[0179] The UE may further be in a registered state (e.g., a "5GMM registered" state) and a deregistered state (e.g., a "5GMM deregistered" state). When the UE successfully registers with the 5G system, the UE may enter the registered state. Otherwise, the UE may be in the deregistered state. The UE may be in the registered state while in an idle mode accessed via 3GPP, a connected mode accessed via 3GPP, or a connected inactive mode accessed via 3GPP.

[0180] In connected mode, the UE can connect to 5G RAN and 5G CN but minimize signaling and power consumption.

[0181] One or more of the following examples relate to 3GPP TS 24.501, which is a technical specification related to the NAS protocol for 5G systems. However, it will be understood that these examples may be transformed to different standards.

[0182] Likewise, one or more of the following examples relate to 5G. However, it will be appreciated that these examples may be transformed to different radio access technologies.

[0183] When the UE is in "5GMM connected" mode with 3GPP access or in "5GMM connected" mode with RRC inactivity indication, the UE NAS layer may receive a fallback indication from a lower layer (i.e., the RRC layer). The UE RRC layer may send a fallback indication to the UE NAS layer when the UE RRC layer receives an "RRC setup" message from the gNB in ​​response to:

[0184] - an "RRC Reestablishment Request" message sent by the UE in "5GMM Connected" mode accessed via 3GPP; or

[0185] -RRC RESUME REQUEST message sent by the UE in “5GMM CONNECTED” mode with RRC Inactivity Indication.

[0186] Typically, upon receiving a fallback indication, the UE NAS layer initiates a NAS procedure. Other details regarding the UE's behavior upon receiving a fallback indication may vary depending on the following:

[0187] - The mode of the UE when the UE receives a fallback indication;

[0188] - the presence of pending uplink user data; and

[0189] - The existence of pending NAS procedures and the type of pending NAS procedures.

[0190] The NAS process may refer to a registration process, a service request process, a deregistration process, a notification process, a paging process, a NAS transmission process, a 5GMM state process, a master authentication and key negotiation process, a security mode control process, an identification process, a general UE configuration update process or other processes.

[0191] According to 3GPP TS 24.501, if the UE has pending uplink user data or pending 5GMM procedures, the UE may initiate a registration procedure, a service request procedure, or a deregistration procedure. 3GPP TS 24.501 further describes that in some cases, the uplink (UL) data status IE in the "Registration Request" or "Service Request" message may indicate the PDU session for which the user plane resources were active before the fallback indication was received.

[0192] A shortcoming of 3GPP TS 24.501 is that it incorrectly describes or ignores multiple situations in which the NAS layer of the UE may invoke a service request procedure or a registration procedure after receiving a fallback indication from the RRC layer. As a result, when the UE invokes a service request procedure or a registration procedure, 3GPP TS 24.501 does not describe the setting of the service type information element (IE) in the "Service Request" message at all, and does not completely describe the setting of the UL data status IE in the "Service Request" message or the "Registration Request" message.

[0193] One or more of the following examples address the deficiencies of 3GPP TS 24.501 (in Section 5.6.1.1 of 3GPP TS 24.501) by supplementing existing cases a), b), c), d), e), f), g) and h) that are not related to fallback indications from lower layers, while cases i), j), k) and l) handle the service request process initiated after receiving a fallback indication from a lower layer.

[0194] In case i), the UE may be in connected mode over 3GPP access or in connected inactive mode. The NAS layer function may receive a fallback indication from the RRC layer function. The UE may have pending uplink user data but no pending NAS procedures.

[0195] In case j), the UE may be in connected mode over 3GPP access or in connected inactive mode. The NAS layer function may receive a fallback indication from the RRC layer function. The UE may have a pending service request procedure invoked for another reason other than Emergency Service Fallback (ESFB).

[0196] For example, the pending service request procedure may have been invoked because the UE received a notification message with an access type IE indicating non-3GPP access over a 3GPP access.

[0197] Alternatively, the pending service request procedure may have been invoked because the UE in connected mode or in connected inactive mode has pending user data due to non-user plane resources established for a PDU session for user data transfer.

[0198] In case k), the UE may be in connected mode over 3GPP access or in connected inactive mode. The NAS layer function may receive a fallback indication from the RRC layer function. The UE may have a pending service request procedure invoked due to ESFB.

[0199] In case 1), the UE may be in connected mode via 3GPP access or in connected inactive mode. The NAS layer function may receive a fallback indication from the RRC layer function. The UE may have pending NAS procedures other than registration, service request or deregistration procedures.

[0200] One or more of the following examples address other deficiencies of 3GPP TS 24.501 by setting the Service Type IE in the "Service Request" message as described below.

[0201] When condition i) is met, the service type IE in the "service request" may be set to 'high priority access', 'emergency service' or 'data'.

[0202] When condition j) is met, the service type IE in the "service request" may be set to 'mobile terminated service', 'high priority access', 'emergency service' or 'data'.

[0203] When condition k) is met, the service type IE in the "service request" may be set to 'ESFB'.

[0204] When condition 1) is met, the service type IE in the "service request" may be set to 'emergency service', 'high priority access' or 'signaling'.

[0205] One or more of the following examples further address the deficiencies of 3GPP TS 24.501 by setting the UL Data Status IE in the "Service Request" as described below.

[0206] When condition i) is met, the UL Data Status IE in the "Service Request" may indicate the PDU session for which the user plane resources were active before the fallback indication was received.

[0207] When condition j) is met, the UL Data Status IE in the "Service Request" may indicate the PDU sessions (if any) for which the user plane resources were active before the fallback indication was received and / or the PDU sessions (if any) for which the user plane resources were inactive before the fallback indication was received and the UE has pending user data to be sent via the 3GPP access.

[0208] When condition k) is met, the UL Data Status IE in the "Service Request" may not be specified.

[0209] When condition 1) is satisfied, when the UE is in connected mode, the UL Data Status IE in the Service Request may indicate the PDU sessions (if any) that were active for the user plane resources before the fallback indication was received. If the UE does not have an always-on PDU session, the UL Data Status IE may not be included in the Service Request message when the UE is in connected inactive mode. If the UE in connected inactive mode has one or more always-on PDU sessions, the UE may indicate the always-on PDU sessions via the UL Data Status IE in the Service Request message. For simplicity, regardless of the mode of the UE (i.e., connected mode or connected inactive mode), the UL Data Status IE in the Service Request may indicate the PDU sessions (if any) that were active for the user plane resources before the fallback was received.

[0210] In all cases i), j), k) and l), if the UE has one or more always-on PDU sessions and the user plane resources for these PDU sessions are inactive, the UE may include the UL Data Status IE in the SERVICE REQUEST message and indicate that the UE has pending user data to be sent for those PDU sessions.

[0211] The following example addresses the deficiencies of 3GPP TS 24.501 by setting the UL Data Status IE in the Registration Request message as follows:

[0212] The UE may be in connected mode over 3GPP access or in connected inactive mode. The NAS layer function may receive a fallback indication from the RRC layer function. The UE may have a pending registration procedure. In this case, the UL Data Status IE in the Registration Request message may indicate the PDU sessions (if any) for which the user plane resources were active before the fallback indication was received and / or the PDU sessions (if any) for which the user plane resources were inactive before the fallback indication was received and the UE has pending user data to be sent over 3GPP access.

[0213] Figure 6 A schematic diagram of a diagram showing a method of performing a service request procedure. The method may be performed by a UE and more specifically by a NAS layer function.

[0214] In step 602, the NAS layer function of the UE may determine that one of cases i), j), k), or l) for invoking a service request procedure is satisfied.

[0215] In step 604, the NAS layer function of the UE may invoke a service request procedure.

[0216] In step 606, the NAS layer function of the UE may set the service type IE in the "Service Request" message according to the conditions met. That is, when conditions i), j), k) or l) are met, the NAS layer function of the UE may set the service type IE in the "Service Request" message differently. Figure 8 , Fig. 9 , Fig.11 as well as Fig.13 This step is discussed in more detail.

[0217] In step 608, the NAS layer function of the UE may set the UL data status IE in the "Service Request" message according to the conditions met. That is, when conditions i), j), k) or l) are met, the NAS layer function of the UE may set the UL data status IE in the "Service Request" message differently. Figure 7 , Fig.10 and Fig.12 This step is discussed in more detail.

[0218] In step 610, the NAS layer function of the UE may send a "service request" message to the NAS layer function of the CN. The NAS layer function of the CN may be an access management function (AMF). The NAS layer function of the UE may start a service request retransmission timer (e.g., T3517). The NAS layer function of the UE may increment a service request attempt counter.

[0219] In step 612, the NAS layer function of the UE may determine that the service request procedure has been completed. The determination may depend on the conditions that are satisfied.

[0220] For example, when one of the situations i), j) or k) is met, after receiving the "Service Accept" message from the NAS layer function of the CN, the NAS layer function of the UE may determine that the service request process is completed. The NAS layer function of the UE may then stop the service request retransmission timer and reset the service request attempt counter.

[0221] Alternatively, when condition 1) is met, after receiving an indication from the RRC layer function of the UE that the UE has changed to S1 mode or E-UTRA is connected to 5GCN, the NAS layer function of the UE may determine that the service request process is completed. The NAS layer function of the UE may then stop the service request retransmission timer.

[0222] Figure 7 A schematic diagram of a diagram showing a method of setting the UL Data Status IE in a "SERVICE REQUEST" message when case i) is met. The method may be performed by a UE and more specifically by a NAS layer function.

[0223] In step 702, the NAS function of the UE may determine that case i) is satisfied. In particular, the NAS function of the UE may determine that the UE has pending UL user data but no pending NAS procedure.

[0224] In step 704, the NAS function of the UE may set the UL Data Status IE in the SERVICE REQUEST message to indicate the packet data unit (PDU) session for which the user plane resources were active before receiving the fallback indication. The fallback indication may be received from the RRC layer function of the UE.

[0225] Figure 8 A schematic diagram of a diagram showing a method of setting the Service Type IE in a "Service Request" message when case i) is met. The method may be performed by a UE and more specifically by a NAS layer function.

[0226] In step 802, the NAS layer function of the UE may determine that case i) is satisfied. Specifically, the NAS function of the UE may determine that the UE has pending UL user data but no pending NAS procedure.

[0227] In step 804, the NAS layer function of the UE may determine whether the UE is configured for high priority access in the selected public land mobile network (PLMN). If the UE is configured for high priority access in the selected PLMN, the method proceeds to step 806. If the UE is not configured for high priority access in the selected PLMN, the method proceeds to step 808.

[0228] In step 806 (ie, the UE is configured for high priority access in the selected PLMN), the NAS layer function of the UE may set the Service Type IE in the Service Request message to 'High Priority Access'.

[0229] In step 808 (i.e., the UE is not configured for high priority access in the selected PLMN), the NAS layer function of the UE may determine whether an emergency PDU session is indicated in the UL data status IE in the "service request" message. If an emergency PDU session is indicated in the UL data status IE in the "service request" message, the method proceeds to step 810. If an emergency PDU session is not indicated in the UL data status IE in the "service request" message, the method proceeds to step 812.

[0230] In step 810 (ie, the emergency PDU session is indicated in the UL Data Status IE in the "Service Request" message), the NAS layer function of the UE may set the Service Type IE in the "Service Request" message to 'Emergency Service'.

[0231] In step 812 (ie, no emergency PDU session is indicated in the UL Data Status IE in the "Service Request" message), the NAS layer function of the UE may set the Service Type IE in the "Service Request" message to 'Data'.

[0232] Fig. 9 A schematic diagram of a diagram showing a method of setting the UL Data Status IE in a "SERVICE REQUEST" message when case j) is met. The method may be performed by a UE and more specifically by a NAS layer function.

[0233] In step 902, the NAS function of the UE may determine that condition j) is satisfied. In particular, the NAS function of the UE may determine that the UE has a pending service request procedure invoked for another reason other than emergency service fallback (ESFB).

[0234] For example, the pending service request procedure may have been invoked because the UE received a notification message with an access type indicating non-3GPP access over a 3GPP access.

[0235] Alternatively, the pending service request procedure may have been invoked because the UE in connected mode or in connected inactive mode has pending user data due to non-user plane resources established for a PDU session for user data transfer.

[0236] In step 904, the NAS function of the UE may set the UL Data Status IE in the "Service Request" message to indicate the PDU session for which the user plane resources were active before the fallback indication was received from the RRC layer entity. Alternatively or additionally, the NAS function of the UE may set the UL Data Status IE in the "Service Request" message to indicate that the user plane resources were inactive before the fallback indication was received and the UE has pending user data to be sent via the 3GPP access PDU session (if any).

[0237] Fig.10 A schematic diagram of a diagram showing a method of setting the Service Type IE in a "Service Request" message when case j) is met. The method may be performed by a UE and more specifically by a NAS layer function.

[0238] In step 1002, the NAS layer function of the UE may determine that condition j) is satisfied. In particular, the NAS function of the UE may determine that the UE has a pending service request procedure invoked due to another reason other than ESFB.

[0239] If the pending service request procedure has been invoked because the UE received a notification message having an access type indicating non-3GPP access through 3GPP access, the method proceeds to step 1004 .

[0240] If the pending service request procedure has been invoked because the UE in connected mode or in connected inactive mode has user data pending due to non-user plane resources established for a PDU session for user data transfer, the method proceeds to step 1006 .

[0241] In step 1004, ie, the pending service request procedure has been invoked because the UE received a notification message with an access type indicating non-3GPP access via 3GPP access, the NAS layer function of the UE may set the service type IE in the "Service Request" message to 'Mobile Terminated Service'.

[0242] In step 1006 (i.e., the pending service request procedure has been invoked because the UE in connected mode has user data pending due to non-user plane resources established for a PDU session for user data transfer), the NAS layer function of the UE may determine whether the UE is configured for high priority access in the selected public land mobile network (PLMN).

[0243] If the UE is configured for high priority access in the selected PLMN, the method proceeds to step 1008. If the UE is not configured for high priority access in the selected PLMN, the method proceeds to step 1010.

[0244] In step 1008 (ie, the UE is configured for high priority access in the selected PLMN), the NAS layer function of the UE may set the Service Type IE in the Service Request message to 'High Priority Access'.

[0245] In step 1010 (ie, the UE is not configured for high priority access in the selected PLMN), the NAS layer function of the UE may determine whether an emergency PDU session is indicated in the UL Data Status IE in the SERVICE REQUEST message.

[0246] If the emergency PDU session is indicated in the UL Data Status IE in the “Service Request” message, the method proceeds to step 1012. If the emergency PDU session is not indicated in the UL Data Status IE in the “Service Request” message, the method proceeds to step 1014.

[0247] In step 1012 (ie, the emergency PDU session is indicated in the UL Data Status IE in the "Service Request" message), the NAS layer function of the UE may set the Service Type IE in the "Service Request" message to 'Emergency Service'.

[0248] In step 1014 (ie, no emergency PDU session is indicated in the UL Data Status IE in the "Service Request" message), the NAS layer function of the UE may set the Service Type IE in the "Service Request" message to 'Data'.

[0249] Alternatively or additionally, the NAS layer function of the UE may determine whether to include the allowed PDU session status IE in the "service request" message. For example, if the UE invokes a pending service request procedure because the UE receives a notification message with an access type indicating non-3GPP access through 3GPP access, the NAS layer function of the UE may determine to include the allowed PDU session status IE in the "service request" message.

[0250] The NAS layer function of the UE may then determine whether the UE has one or more PDU sessions over non-3GPP access associated with a single network slice selection assistance information (S-NSSAI) included in the allowed network slice selection assistance information (NSSAI) for 3GPP access, and the UE allows user plane resources for the PDU sessions over the non-3GPP access to be re-established over the 3GPP access.

[0251] If the UE has one or more PDU sessions over non-3GPP access associated with the S-NSSAI for 3GPP access included in the allowed NSSAI, and the UE allows user plane resources for the PDU sessions over non-3GPP access to be re-established over 3GPP access, the UE may set the allowed PDU session status IE to indicate the one or more PDU sessions.

[0252] If the UE does not have a PDU session over non-3GPP access associated with the S-NSSAI for 3GPP access included in the allowed NSSAI, or the UE allows user plane resources for a PDU session over non-3GPP access to be re-established over 3GPP access, the UE may set the allowed PDU session status IE to indicate no PDU session.

[0253] Fig.11 A schematic diagram of a diagram showing a method of setting the Service Type IE in a "Service Request" message when condition k) is met. The method may be performed by a user equipment and in particular by a NAS function.

[0254] In step 1102, the NAS function of the UE may determine that condition k) is satisfied. In particular, the NAS function of the UE may determine that the UE has a pending service request procedure invoked due to emergency service fallback.

[0255] In step 1104, the NAS function of the UE may set the service type IE in the "Service Request" message to 'Emergency Service Fallback'.

[0256] Fig.12 A schematic diagram of a diagram showing a method of setting the UL Data Status IE in a "Service Request" message when condition 1) is met. The method may be performed by a user equipment and in particular by a NAS function.

[0257] In step 1202, the NAS function of the UE may determine that condition 1) is satisfied. In particular, the NAS function of the UE may determine that the UE has a pending NAS procedure other than a registration procedure, a service request procedure, or a deregistration procedure.

[0258] In step 1204, the NAS function of the UE may determine whether the UE is in a connected mode or in a connected inactive mode. If the UE is in a connected mode, the method proceeds to 1206. If the UE is in a connected inactive mode, the method proceeds to 1208.

[0259] In step 1206, the NAS function of the UE may set the UL Data Status IE in the SERVICE REQUEST message to indicate the PDU sessions (if any) for which the user plane resources were active before receiving the fallback indication. The fallback indication may be received from the RRC layer function of the UE.

[0260] In step 1208, the NAS function of the UE may set the UL Data Status IE in the SERVICE REQUEST message to indicate the always-on PDU session (if any). If there is no always-on PDU session, the NAS function of the UE may not include the UL Data Status IE in the SERVICE REQUEST message.

[0261] Fig.13 A schematic diagram of a diagram showing a method of setting the Service Type IE in a “Service Request” message when condition 1) is met.

[0262] In step 1302, the NAS function of the UE may determine that condition 1) is satisfied. In particular, the NAS function of the UE may determine that the UE has a pending NAS procedure other than a registration procedure, a service request procedure, or a deregistration procedure.

[0263] In step 1304, the NAS layer function of the UE may determine whether the UE is configured for high priority access in the selected public land mobile network (PLMN).

[0264] If the UE is configured for high priority access in the selected PLMN, the method proceeds to step 1306. If the UE is not configured for high priority access in the selected PLMN, the method proceeds to step 1308.

[0265] In step 1306 (ie, the UE is configured for high priority access in the selected PLMN), the NAS layer function of the UE may set the Service Type IE in the Service Request message to 'High Priority Access'.

[0266] In step 1308 (ie, the UE is not configured for high priority access in the selected PLMN), the NAS layer function of the UE may determine whether there is a "UL NAS Transfer" message with the Request Type IE set to 'Initial Emergency Request' or 'Existing Emergency PDU Session'.

[0267] If there is a pending "UL NAS Transfer" message with the Request Type IE set to 'Initial Emergency Request' or 'Existing Emergency PDU Session', the method proceeds to step 1310. If there is no pending "UL NAS Transfer" message with the Request Type IE set to 'Initial Emergency Request' or 'Existing Emergency PDU Session', the method proceeds to step 1312.

[0268] In step 1310 (ie, there is a pending UL NAS Transfer message with the Request Type IE set to 'Initial Emergency Request' or 'Existing Emergency PDU Session'), the NAS layer function of the UE may set the Service Type IE in the Service Request message to 'Emergency Service'.

[0269] In step 1312 (ie, there is no pending UL NAS Transfer message with the Request Type IE set to 'Initial Emergency Request' or 'Existing Emergency PDU Session'), the NAS layer function of the UE may set the Service Type IE in the Service Request message to 'Signaling'.

[0270] Fig.14 A schematic diagram of non-volatile memory media 1400a (e.g., a computer disk (CD) or digital versatile disk (DVD)) and 1400b (e.g., a universal serial bus (USB) memory stick) storing instructions and / or parameters 1402 that, when executed by a processor, allow the processor to perform Figures 6 to 13 One or more of the steps of the method.

[0271] It will be appreciated that one or more of the above examples may be incorporated into a modified version of 3GPP TS 24.501, for example by incorporating one or more of the following sections.

[0272] 5.3.1.2 Rebuilding N1 NAS signaling connection

[0273] When a UE in "5GMM Connected" mode over 3GPP access receives a fallback indication from lower layers and the UE has pending uplink user data but no pending NAS procedures, the UE shall:

[0274] a) enter "5GMM Idle" mode; and

[0275] b) Initiate the service request process (see subclause 5.6.1).

[0276] When a UE in "5GMM Connected" mode over 3GPP access receives a fallback indication from lower layers and the UE has a pending registration procedure, service request procedure or deregistration procedure, the UE shall:

[0277] a) enter "5GMM Idle" mode; and

[0278] b) Continue with pending procedures (see subclauses 5.5.1.3, 5.6.1 and 5.5.2.2).

[0279] When a UE in "5GMM Connected" mode over 3GPP access receives a fallback indication from lower layers and the UE has pending NAS procedures other than a Registration procedure, a Service Request procedure or a Deregistration procedure, the UE shall:

[0280] a) Enter "5GMM idle" mode;

[0281] b) initiate the service request process (see subclause 5.6.1); and

[0282] c) Upon successful completion of the service request process, continue with any pending processes.

[0283] *****Next Change*****

[0284] 5.3.1.4 "5GMM Connected" Mode with RRC Inactivity Indication

[0285] This subclause only applies to UE in 5GMM mode accessed through 3GPP.

[0286] The UE is in "5GMM Connected" mode with RRC Inactivity Indication when the UE is in the following situations:

[0287] a) "5GMM connected" mode at the NAS layer over 3GPP access; and

[0288] b) RRC_INACTIVE state at the AS layer (see 3GPP TS 38.300

[27] ).

[0289] Unless otherwise stated, the UE behavior in “5GMM Connected” mode with RRC Inactivity Indication shall follow the UE behavior in “5GMM Connected” mode over 3GPP access, except for the following cases:

[0290] a) The UE shall apply mobility restrictions; and

[0291] b) The UE will perform the PLMN selection process,

[0292] Just like being in "5GMM Idle" mode accessed through 3GPP.

[0293] Upon receiving an indication from lower layers that the UE has transitioned to the RRC_INACTIVE state, the UE shall transition from “5GMM Connected” mode accessed over 3GPP to “5GMM Connected” mode with RRC Inactivity indication.

[0294] After:

[0295] - trigger a process that requires sending a NAS message; or

[0296] - Uplink user data packets will be sent for the PDU session with suspended user plane resources;

[0297] A UE in “5GMM Connected” mode with RRC Inactivity Indication over 3GPP access shall request lower layers to transition to the RRC_CONNECTED state (see 3GPP TS 38.300

[27] ).

[0298] Upon receiving an indication from lower layers that the UE has transitioned to the RRC_CONNECTED state, the UE shall transition from “5GMM Connected” mode with RRC Inactivity Indication to “5GMM Connected” mode over 3GPP access (see 3GPP TS 38.300

[27] ).

[0299] NOTE: The AMF is able to be aware of the UE transitioning between “5GMM Connected” mode and “5GMM Connected” mode with RRC Inactivity Indication (see 3GPP TS 23.502 [9]).

[0300] Upon selection of a PLMN that is not equivalent to the registered PLMN, the UE shall trigger a transition from "5GMM Connected" mode with RRC Inactivity indication to "5GMM Idle" mode. Upon entering a new PLMN in the list of equivalent PLMNs, the UE shall not trigger a transition from "5GMM Connected" mode with RRC Inactivity indication to "5GMM Idle" mode.

[0301] If the UE requests lower layers to transition to the RRC_CONNECTED state when initiating a registration procedure, a service request procedure or a deregistration procedure, then following the fallback indication from lower layers, the UE shall:

[0302] - enter "5GMM Idle" mode; and

[0303] - Continue with pending procedures (see subclauses 5.5.1.3, 5.6.1 and 5.5.2.2).

[0304] If the UE requests lower layers to transition to the RRC_CONNECTED state for reasons other than the initiation of a Registration procedure, a Service Request procedure or a Deregistration procedure, then following a fallback indication from lower layers the UE shall:

[0305] -Enter "5GMM Idle" mode;

[0306] - initiate the service request process (see subclause 5.6.1); and

[0307] - Upon successful completion of the service request process, proceed with any pending processes.

[0308] If a UE in "5GMM Connected" mode with RRC Inactivity Indication receives a fallback indication from lower layers and the UE has pending uplink user data but no pending NAS procedures, the UE shall:

[0309] - enter "5GMM Idle" mode; and

[0310] - Initiate the Service Request process (see subclause 5.6.1).

[0311] The UE shall transition from “5GMM Connected” mode with RRC Inactivity Indication to “5GMM Idle” mode over 3GPP access and initiate the registration procedure for mobility and periodic registration update for mobility (i.e. 5GS Registration Type IE set to “Mobility Registration Update” in the “Registration Request” message) for NAS signalling connection resumption as specified in subclause 5.5.1.3.2 upon receiving from lower layers:

[0312] a) an indication that the transition from the RRC_INACTIVE state to the RRC_CONNECTED state has failed; or

[0313] b) There is no fallback indication for the recovery request from NAS.

[0314] The UE shall transition from “5GMM Connected” mode with RRC Inactivity Indication to “5GMM Idle” mode over 3GPP access upon receipt of:

[0315] a) an indication of a transition from the RRC_INACTIVE state to the RRC_IDLE state;

[0316] b) AMF paging indication; or

[0317] c) An indication that the UE supports cell selection for E-UTRAN or another RAT.

[0318] *****Next Change*****

[0319] 5.5.1.3.2 Mobility and Periodic Registration Update Initiation

[0320] A UE in state "5GMM REGISTERED" shall initiate the registration procedure for mobility and periodic registration updates by sending a "Registration Request" message to the AMF,

[0321] a) When the UE detects entry into a tracking area that is not in the list of tracking areas that the UE previously registered with the AMF;

[0322] b) When the periodic registration update timer T3512 expires;

[0323] c) when requested by a "Configuration Update Command" message;

[0324] d) when the UE in state 5GMM-REGISTERED.ATTEMPTING-REGISTRATION-UPDATE receives a paging or the UE receives a notification message with an access type of 3GPP access over a non-3GPP access indicating a PDU session associated with a 3GPP access;

[0325] e) After an inter-system change from S1 mode to N1 mode;

[0326] f) when the UE receives an indication from lower layers that the transition from the RRC_INACTIVE state to the RRC_CONNECTED state has failed (see subclause 5.3.1.4);

[0327] g) When the UE changes 5GMM capabilities or S1 UE network capabilities or both;

[0328] h) When the usage settings of the UE are changed;

[0329] i) When the UE needs to change the slice it is currently registered to;

[0330] j) When the UE changes UE-specific DRX parameters;

[0331] k) when the UE in state 5GMM-REGISTERED.ATTEMPTING-REGISTRATION-UPDATE receives a request from upper layers to establish an emergency PDU session or to perform emergency service fallback;

[0332] l) when the UE needs to register for SMS over NAS, indicate a change in requirements to use SMS over NAS, or deregister from SMS over NAS;

[0333] m) when the UE needs to indicate the PDU Session status to the network following local release of the PDU Session as specified in subclauses 6.4.1.5 and 6.4.3.5;

[0334] n) When a UE in “5GMM Idle” mode changes the radio capabilities of the NG-RAN;

[0335] o) when the UE receives a fallback indication from lower layers without a resumption request from NAS (see subclause 5.3.1.4);

[0336] p) When the UE receives a fallback indication from lower layers and has pending registration procedures for mobility and periodic registration updates (see subclauses 5.3.1.2 and 5.3.1.4).

[0337] If item b) is the only reason for initiating the Registration procedure for both Mobility and Periodic Registration Update Registration, the UE shall indicate "Periodic Registration Update" in the 5GS Registration Type IE; otherwise, the UE shall indicate "Mobility Registration Update".

[0338] If the UE indicates "Mobility Registration Update" in the 5GS Registration Type IE and the UE supports S1 mode, the UE shall:

[0339] - Set the S1 Mode bit to "S1 Mode Supported" in the 5GMM Capabilities IE of the "Registration Request" message;

[0340] - include the S1 UE Network Capabilities IE in the Registration Request message; and

[0341] - If the UE supports sending an Attach Request message containing a PDN Connection Request message with the Request Type set to "Handover" to transfer a PDU Session from N1 Mode to S1 Mode, then the HO Attach bit is set in the 5GMM Capability IE of the Registration Request message to "Attach Request message containing a PDN Connection Request message with the Request Type set to "Handover" to transfer a PDU Session from N1 Mode to supported S1 Mode".

[0342] If a UE operating in single registration mode performs an inter-system change from S1 mode to N1 mode and has one or more stored UE policy parts, the UE shall include a "UPSI List Transfer" message in the payload container IE of the "Registration Request" message (see Annex D).

[0343] When a UE in state "5GMM REGISTERED" needs to request the use of SMS transport over NAS or the current requirement to use SMS transport over NAS changes in the UE, the UE shall initiate the registration procedure for mobility and periodic updates by sending a "Registration Request" message to the AMF. The UE shall set the SMS Request bit of the 5GS Registration Type IE in the "Registration Request" message as specified in subclause 5.5.1.2.2.

[0344] When the Registration procedure for mobility and periodic Registration Update is initiated and the requirement to use SMS over NAS has not changed in the UE, the UE shall set the SMS Requested bit of the 5GS Registration Type IE in the Registration Request message to the same value as indicated by the UE in the last Registration Request message.

[0345] If the UE no longer needs to use SMS over NAS, the UE shall set the SMS Request bit of the 5GS Registration Type IE to "SMS over NAS not supported" in the Registration Request message.

[0346] After sending the "Registration Request" message to the AMF, the UE will start timer T3510. If timer T3502 is currently running, the UE will stop timer T3502. If timer T3511 is currently running, the UE will stop timer T3511.

[0347] If the last visited registered TAI is available, the UE shall include the last visited registered TAI in the Registration Request message.

[0348] The UE shall handle the 5GS Mobility Identity IE in the Registration Request message as follows:

[0349] a) If the UE is operating in single registration mode and performs an inter-system change from S1 mode to N1 mode, and the UE maintains a valid 4G-GUTI, the UE shall include in the 5GS Mobility Identity IE the 5G-GUTI mapped from the 4G-GUTI as specified in 3GPP TS 23.003 [4]. Additionally, if the UE maintains a valid 5G-GUTI, the UE shall include the 5G-GUTI in the Additional GUTI IE in the Registration Request message; and

[0350] b) For all other cases, if the UE holds a valid 5G-GUTI, the UE shall indicate the 5G-GUTI in the 5GS Mobile Identity IE.

[0351] If the UE supports MICO mode and requests to use MICO mode, the UE shall include the MICO Indication IE in the Registration Request message.

[0352] If the UE wants to change UE-specific DRX parameters, the UE shall include the requested DRX parameters IE in the REGISTRATION REQUEST message.

[0353] If the UE wants LADN information for a specific LADN DNN, or indicates a request for LADN information as specified in 3GPP TS 23.501 [8], the UE shall include the LADN Indication IE in the Registration Request message and:

[0354] - request a specific LADN DNN by including a LADN DNN value in the LADN Indication IE for each UE requesting LADN information; or

[0355] - Indicates a request for LADN information by not including any LADN DNN value in the LADN Indication IE.

[0356] If the UE is initiating a registration procedure for mobility and periodic registration updates, the UE may include an Uplink Data Status IE to indicate which PDU Session(s) have pending user data to be sent. If the UE has one or more active Always-On PDU Sessions and no user plane resources are established for these PDU Sessions, the UE shall include an Uplink Data Status IE and indicate that for those PDU Sessions, the UE has pending user data to be sent. If the UE is outside a LADN service area, the UE shall not include PDU Sessions for LADN in the Uplink Data Status IE.

[0357] If the UE has one or more active PDU Sessions that are not accepted by the network as Always-On PDU Sessions and no uplink user data is pending to be sent for those PDU Sessions, the UE shall not include those PDU Sessions in the Uplink Data Status IE in the Registration Request message.

[0358] When initiating the registration procedure for mobility and periodic registration updates in "5GMM Idle" mode, the UE may include a PDU Session Status IE in the "Registration Request" message, wherein the PDU Session Status IE indicates which PDU sessions associated with the access type "Registration Request" message has been sent are active in the UE.

[0359] If the UE receives a paging message with an access type indicating non-3GPP access, the UE shall include the Allowed PDU Session State IE in the Registration Request message, indicating that the UE allows PDU sessions for which user plane resources are re-established over 3GPP access.

[0360] If a UE operating in single registration mode performs an inter-system change from S1 mode to N1 mode, the UE:

[0361] a) the Registration Request message shall include the UE Status IE with the EMM Registration Status set to "UE is in EMM Registered State";

[0362] NOTE 1: Including the UE Status IE with this setting corresponds to an indication that the UE is "moving from the EPC" as specified in subclauses 4.11.1.3.3 and 4.11.2.3 of 3GPP TS 23.502 [9].

[0363] b) a PDU Session Status IE may be included in the Registration Request message, indicating the status of PDU sessions from the PDN connection mapped during the intersystem change from S1 mode to N1 mode, for which the EPS indicates support for interworking with 5GS (if any) (see subclause 6.1.4.1); and

[0364] c) The "Tracking Area Update Request" message as specified in 3GPP TS 24.301

[15] shall be included in the EPS NAS message container IE in the "Registration Request" message.

[0365] If a UE operating in single registration mode performs an inter-system change from S1 mode to N1 mode and the UE has at least one PDN connection with a valid EPS bearer context, the UE shall include in the requested NSSAI IE of the REGISTRATION REQUEST message:

[0366] a) S-NSSAI, the S-NSSAI:

[0367] 1) associated with an established PDN connection; and

[0368] 2) is applicable in the serving PLMN; and

[0369] b) If mapping information is available at the UE, these S-NSSAIs are mapped to the S-NSSAIs of the configured NSSAIs of the HPLMN.

[0370] The UE shall include a requested NSSAI containing the S-NSSAI corresponding to the slice the UE wants to register with and a mapping of the requested NSSAI to each S-NSSAI of the requested NSSAI to the S-NSSAI of the configured NSSAI of the HPLMN, if available, in the Registration Request message. If the UE has an allowed NSSAI or a configured NSSAI for the current PLMN, then:

[0371] a) If the UE does not have an allowed NSSAI for the current PLMN, the requested NSSAI shall be the configured NSSAI of the current PLMN, or a subset of that NSSAI as described below;

[0372] b) if the UE has an allowed NSSAI for the current PLMN, the requested NSSAI shall be the allowed NSSAI of the current PLMN, or a subset of that NSSAI as described below; or

[0373] c) the allowed NSSAI of the current PLMN, or a subset of said NSSAI as described below, plus one or more S-NSSAIs from the configured NSSAIs for which there is no corresponding S-NSSAI in the allowed NSSAIs, and which is neither in the rejected NSSAI of the current PLMN nor in the combination of the rejected NSSAI of the current PLMN and the registration area.

[0374] If the UE has neither an Allowed NSSAI for the current PLMN nor a Configured NSSAI for the current PLMN, but has a Configured NSSAI not associated with a PLMN, the UE shall include the S-NSSAI in the Requested NSSAI IE of the Registration Request message using the Configured NSSAI not associated with the PLMN. If the UE has neither an Allowed NSSAI for the current PLMN, nor a Configured NSSAI for the current PLMN, nor a Configured NSSAI not associated with a PLMN, the UE shall not include the Requested NSSAI in the Registration Request message.

[0375] If the S-NSSAI is neither in the rejected NSSAI of the current PLMN nor in the combination of the rejected NSSAI of the current PLMN and the registration area, then the subset of configured NSSAI provided in the requested NSSAI consists of one or more S-NSSAIs in the configured NSSAI applicable to this PLMN.

[0376] If a rejecting S-NSSAI is added through the configuration update procedure and the S-NSSAI is neither in the rejecting NSSAI of the current PLMN nor in the combination of the rejecting NSSAI of the current PLMN and the registration area, then the subset of allowed NSSAIs provided in the requested NSSAI consists of one or more S-NSSAIs in the allowed NSSAI of this PLMN.

[0377] NOTE 2: How the UE selects the subset of configured NSSAI or allowed NSSAI to be provided in the requested NSSAI is implementation dependent.

[0378] NOTE 3: The number of S-NSSAIs included in the requested NSSAI shall not exceed eight.

[0379] The UE shall set the "Subsequent request pending" indication to 1 if the UE:

[0380] a) Initiate mobility and periodic registration update procedures after requesting upper layers to establish an emergency PDU session;

[0381] b) initiating mobility and periodic registration update procedures upon receipt of a request from upper layers to send NAS signalling associated with emergency services fallback; or

[0382] c) An established NAS signaling connection needs to be prolonged after completion of the registration procedures for mobility and periodic registration updates (eg, because uplink signaling is pending, but no user data is pending).

[0383] For case n), the UE shall set the NG-RAN-RCU bit of the 5GS Registration Type IE to “NG-RAN Radio Capability Update Required” in the Registration Request message.

[0384] For case p), the UE shall include in the REGISTRATION REQUEST message the UL DATA STATUS IE indicating the PDU sessions (if any) for which the user plane resources were active before the fallback indication was received from lower layers, and the PDU sessions (if any) for which the user plane resources were inactive before the fallback indication was received from lower layers and the UE has pending user data to be sent over the 3GPP access.

[0385] *****Next Change*****

[0386] 5.6.1.1 General

[0387] The purpose of the service request procedure is to change the 5GMM mode from "5GMM idle" to "5GMM connected" mode and / or to request the establishment of user plane resources for a PDU session established without user plane resources. In the latter case, if the UE needs to establish user plane resources for a PDU session, the 5GMM mode can be "5GMM idle" mode or "5GMM connected" mode. This procedure is used in the following cases:

[0388] - The network has downlink signalling pending on 3GPP access and the UE is in “5GMM Idle” mode over 3GPP access;

[0389] - The network has downlink signalling pending on a non-3GPP access, the UE is in “5GMM Idle” mode over the non-3GPP access and in “5GMM Idle” or “5GMM Connected” mode over a 3GPP access;

[0390] - The network has uplink signalling pending on 3GPP access and the UE is in “5GMM Idle” mode over 3GPP access;

[0391] - The network has downlink user data pending on 3GPP access and the UE is in “5GMM Idle” mode over 3GPP access;

[0392] - the network has downlink user data pending on a non-3GPP access, the UE is in “5GMM Idle” mode over the non-3GPP access and in “5GMM Idle” or “5GMM Connected” mode over a 3GPP access;

[0393] -The UE has user data pending on 3GPP access and the UE is in “5GMM Idle” or “5GMM Connected” mode over 3GPP access;

[0394] - The network has user data pending on a non-3GPP access and the UE is in “5GMM Connected” mode over the non-3GPP access;

[0395] - a UE in "5GMM Idle" mode over a non-3GPP access receives an indication from lower layers of the non-3GPP access that an access plane connection is established between the UE and the network; or

[0396] - A UE in "5GMM Idle" or "5GMM Connected" mode accessed over 3GPP receives a request for emergency services fallback from upper layers and performs emergency services fallback as specified in subclause 4.13.4.2 of 3GPP TS 23.502 [9].

[0397] When the UE is outside the LADN service area, this procedure shall not be used to initiate signalling related to user data transfer or PDU session management, but only to perform a UE-requested PDU session release procedure associated with a PDU session of the LADN.

[0398] The service request procedure is initiated by the UE, however, the service request procedure can be triggered by the network in the following ways:

[0399] - Paging procedure for delivery of downlink signalling or user data pending on 3GPP access to a UE in “5GMM Idle” mode over 3GPP access (see subclause 5.6.2);

[0400] - Paging procedure for delivery of pending downlink signalling or user data on non-3GPP access to UEs in “5GMM Idle” mode over 3GPP access and in “5GMM Idle” mode over non-3GPP access (see subclause 5.6.2);

[0401] - Notification procedure for delivery of pending downlink signalling or user data on non-3GPP access to UEs in “5GMM connected” mode over 3GPP access and in “5GMM idle” mode over non-3GPP access (see subclause 5.6.3);

[0402] - Notification procedure for delivery of pending downlink signaling or user data on 3GPP access to UEs in “5GMM Idle” mode over 3GPP access and in “5GMM Connected” mode over non-3GPP access (see subclause 5.6.3).

[0403] NOTE: If the UE is in “5GMM Idle” mode over 3GPP access and in “5GMM Connected” mode over non-3GPP access, and downlink signaling or user data pending on the 3GPP access needs to be transferred, the AMF may trigger a notification procedure or a paging procedure based on the implementation.

[0404] The UE shall invoke the Service Request procedure in the following cases:

[0405] a) A UE in “5GMM Idle” mode accessed via 3GPP receives a paging request from the network;

[0406] b) A UE in “5GMM connected” mode accessed over 3GPP receives a notification from the network with an access type indicating non-3GPP access;

[0407] c) A UE in “5GMM Idle” mode accessed through 3GPP has pending uplink signalling;

[0408] d) A UE in “5GMM Idle” mode accessed through 3GPP has pending uplink user data;

[0409] e) A UE in “5GMM Connected” mode has pending user data due to no user plane resources established for a PDU session for transfer of user data;

[0410] f) a UE in “5GMM Idle” mode over a non-3GPP access receives an indication from lower layers of the non-3GPP access that an access plane connection is established between the UE and the network;

[0411] g) a UE in “5GMM Idle” mode over 3GPP access receives a notification from the network with an access type indicating 3GPP access when the UE is in “5GMM Connected” mode over non-3GPP access;

[0412] h) A UE in “5GMM Idle” or “5GMM Connected” mode accessed through 3GPP receives a request for emergency services fallback from upper layers and performs emergency services fallback as specified in subclause 4.13.4.2 of 3GPP TS 23.502 [9].

[0413] i) a UE in “5GMM Connected” mode for access over 3GPP or in “5GMM Connected” mode with RRC Inactivity Indication receives a fallback indication from lower layers (see subclauses 5.3.1.2 and 5.3.1.4) and the UE has pending uplink user data and no pending NAS procedures;

[0414] j) a UE in “5GMM Connected” mode accessed over 3GPP or in “5GMM Connected” mode with RRC Inactivity Indication receives a fallback indication from lower layers (see subclauses 5.3.1.2 and 5.3.1.4) and the UE has a pending service request procedure invoked for a reason other than case h) in this list;

[0415] k) a UE in “5GMM Connected” mode for access over 3GPP or in “5GMM Connected” mode with RRC Inactivity Indication receives a fallback indication from lower layers (see subclauses 5.3.1.2 and 5.3.1.4) and the UE has a pending service request procedure invoked due to case h) in this list; or

[0416] l) A UE in “5GMM Connected” mode over 3GPP access or in “5GMM Connected” mode with RRC Inactivity Indication receives a fallback indication from lower layers (see subclause 5.3.1.4) and the UE has a pending NAS procedure other than a Registration, Service Request or Deregistration procedure.

[0417] If one of the above criteria for invoking the Service Request procedure is met, the UE shall only initiate the Service Request procedure when the following conditions are met:

[0418] - Its 5GS update status is "5U1 updated", and the TAI of the current serving cell is included in the TAI list; and

[0419] - There are no 5GMM specific processes ongoing.

[0420] While the UE is in state 5GMM-SERVICE-REQUEST-INITIATED, the UE shall not invoke the service request procedure.

[0421] The Service Request Attempts Counter is used to limit the number of service request attempts with no response from the network. The Service Request Attempts Counter shall be incremented as specified in subclause 5.6.1.7.

[0422] The service request attempt counter should be reset in the following cases:

[0423] - The registration process is successfully completed;

[0424] - The service request process is successfully completed; or

[0425] - The service request process is rejected as specified in subclause 5.6.1.5.

[0426] *****Next Change*****

[0427] 5.6.1.2 Service Request Process Initiation

[0428] The UE initiates the service request procedure by sending a "Service Request" message to the AMF and starts timer T3517.

[0429] For cases a), b) and g) in subclause 5.6.1.1, the Service Type IE in the Service Request message shall be set to 'Mobile Terminated Service'.

[0430] For cases c), d), e), f), i) and l) in subclause 5.6.1.1, if the UE is a UE configured for high priority access in the selected PLMN, the Service Type IE in the Service Request message shall be set to 'High Priority Access'.

[0431] For cases h) and k) in subclause 5.6.1.1, the UE shall send a SERVICE REQUEST message with the service type set to 'Emergency Services Fallback'.

[0432] For case a) in subclause 5.6.1.1:

[0433] a) If the Paging Request includes an indication of a non-3GPP access type, the Allowed PDU Session Status IE shall be included in the Service Request message. If the UE has established PDU Sessions associated with the S-NSSAI that are included in the Allowed NSSAI for 3GPP access, the UE shall indicate in the Allowed PDU Session Status IE that the UE allows user plane resources to re-establish the PDU Sessions via the 3GPP access. Otherwise, the UE shall not indicate any PDU Sessions in the Allowed PDU Session Status IE.

[0434] b) if the UE has pending uplink user data to be sent over the 3GPP access, the Uplink Data Status IE shall be included in the Service Request message to indicate that the UE has pending PDU sessions for which user data is to be sent; or

[0435] c) Otherwise, the Uplink Data Status IE shall not be included in the SERVICE REQUEST message.

[0436] For case b) in subclause 5.6.1.1:

[0437] a) The Allowed PDU Session Status IE shall be included in the "Service Request" message. If the UE has PDU Sessions associated with the S-NSSAI that are included in the Allowed NSSAI for 3GPP access, the UE shall indicate in the Allowed PDU Session Status IE that the UE allows user plane resources to reestablish the PDU Sessions via 3GPP access. Otherwise, the UE shall not indicate any PDU Sessions in the Allowed PDU Session Status IE.

[0438] b) If the UE has pending uplink user data to be sent via 3GPP access, the Uplink Data Status IE shall be included in the Service Request message to indicate the PDU session for which the UE has pending user data to be sent;

[0439] c) Otherwise, the Uplink Data Status IE shall not be included in the SERVICE REQUEST message.

[0440] For case c) in subclause 5.6.1.1, the Uplink Data Status IE shall not be included in the Service Request message unless the UE has one or more active Always-On PDU Sessions. If the Service Request message is triggered by a request for emergency services from upper layers and both the UE and the network support emergency services in N1 mode, the UE shall set the Service Type IE in the Service Request message to 'Emergency Services'. Otherwise, if the UE is not a UE configured for high priority access in the selected PLMN, the UE shall set the Service Type IE to 'Signalling'.

[0441] For cases d) and e) in subclause 5.6.1.1, the Uplink Data Status IE shall be included in the Service Request message to indicate that the UE has a pending PDU session for user data to be sent. If the UE is not a UE configured for high priority access in the selected PLMN, the Service Type IE in the Service Request message shall be set to 'Data'.

[0442] For case f) in subclause 5.6.1.1:

[0443] a) If the UE has pending uplink user data to send, the Uplink Data Status IE shall be included in the Service Request message to indicate the PDU session for which the UE has pending user data to send. If the UE is not a UE configured for high priority access in the selected PLMN, the Service Type IE in the Service Request message shall be set to 'Data';

[0444] b) Otherwise, if the UE is not a UE configured for high priority access in the selected PLMN, the Service Type IE in the Service Request message shall be set to 'Signalling'.

[0445] For case g) in subclause 5.6.1.1, if the UE has pending uplink user data to send, the Uplink Data Status IE shall be included in the SERVICE REQUEST message to indicate the PDU sessions for which the UE has pending user data to send.

[0446] For case i) in subclause 5.6.1.1, the UE shall include the Uplink Data Status IE in the SERVICE REQUEST message to indicate the PDU sessions for which the user plane resources were active before the fallback indication was received. If the UE is not a UE configured for high priority access in the selected PLMN and:

[0447] a) if there is an Emergency PDU Session indicated in the Uplink Data Status IE, the UE shall set the Service Type IE in the Service Request message to 'Emergency Service'; or

[0448] b) If there is no emergency PDU session indicated in the Uplink Data Status IE, the UE shall set the Service Type IE in the Service Request message to 'Data'.

[0449] For case j) of subclause 5.6.1.1, the UE shall:

[0450] a) Include the Uplink Data Status IE in the SERVICE REQUEST message to indicate:

[0451] 1) the PDU Sessions (if any) for which the user plane resources were active before the fallback indication was received; and

[0452] 2) User plane resources were inactive before receiving the fallback indication and the UE has pending user data to be sent via the 3GPP access PDU session (if any);

[0453] b) Set the Service Type IE in the "Service Request" message as follows:

[0454] 1) If the UE has invoked a pending service request procedure due to case b) in subclause 5.6.1.1, the UE shall set the Service Type IE in the Service Request message to 'Mobile Terminated Service'; or

[0455] 2) If the UE has invoked a pending service request procedure due to case e) in subclause 5.6.1.1 and:

[0456] i) if the UE is a UE configured for high priority access in the selected PLMN, the UE shall set the Service Type IE in the Service Request message to 'High Priority Access'; or

[0457] ii) If the UE is not a UE configured for high priority access in the selected PLMN, and:

[0458] A) If there is an Emergency PDU Session indicated in the Uplink Data Status IE, the UE shall set the Service Type IE in the Service Request message to 'Emergency Service'; or

[0459] B) If there is no emergency PDU session indicated in the Uplink Data Status IE, the UE shall set the Service Type IE in the Service Request message to 'Data'; and

[0460] c) If the UE has invoked a pending service request procedure due to case b) in subclause 5.6.1.1, the Allowed PDU Session Status IE is included in the Service Request message. If the UE has one or more PDU Sessions over non-3GPP access associated with the S-NSSAI for 3GPP access included in the Allowed NSSAI, and the UE allows user plane resources for the PDU Sessions over non-3GPP access to be re-established over 3GPP access, the UE shall indicate the PDU Sessions in the Allowed PDU Session Status IE. Otherwise, the UE shall not indicate the PDU Sessions in the Allowed PDU Session Status IE.

[0461] For case l) in subclause 5.6.1.1:

[0462] a) The UE shall handle the inclusion of the Uplink Data Status IE in the SERVICE REQUEST message as follows:

[0463] 1) If a UE in “5GMM Connected” mode accessed over 3GPP invokes the Service Request procedure, the UE shall include the Uplink Data Status IE in the “Service Request” message to indicate the PDU Sessions (if any) that were active for the user plane resources before the fallback indication was received; or

[0464] 2) If a UE in “5GMM Connected” mode with RRC Inactivity Indication invokes the Service Request procedure, the UE SHOULD NOT include the Uplink Data Status IE in the “Service Request” message unless the UE has one or more active Always-On PDU Sessions; and

[0465] b) A UE that is not configured for high priority access in the selected PLMN shall set the Service Type IE in the Service Request message as follows:

[0466] 1) If the pending message is a "UL NAS Transfer" message with the Request Type IE set to 'Initial Emergency Request' or 'Existing Emergency PDU Session', the UE shall set the Service Type IE in the "Service Request" message to 'Emergency Service'; or

[0467] 2) If the pending message is not a "UL NAS Transfer" message with the Request Type IE set to 'Initial Emergency Request' or 'Existing Emergency PDU Session', the UE shall set the Service Type IE in the "Service Request" message to 'Signalling'.

[0468] The UE shall include a valid 5G-S-TMSI in the 5G-S-TMSI IE of the SERVICE REQUEST message.

[0469] If the UE has one or more active Always-On PDU Sessions and no User Plane resources are established for these PDU Sessions, the UE shall include the Uplink Data Status IE in the SERVICE REQUEST message and indicate that for those PDU Sessions the UE has pending user data to be sent.

[0470] If the UE has one or more active PDU Sessions that are not accepted by the network as always-on PDU Sessions and no uplink user data is pending to be sent for those PDU Sessions, the UE shall not include those PDU Sessions in the Uplink Data Status IE in the SERVICE REQUEST message.

[0471] The PDU Session Status information element may be included in the "Service Request" message to indicate the PDU Sessions available in the UE associated with the access type "Service Request" message sent. If the PDU Session Status information element is included in the "Service Request" message, the AMF shall locally (without peer signaling between the UE and the network) release all those PDU Sessions that were active on the AMF side associated with the access type "Service Request" message sent, but indicated as inactive by the UE, and shall request the SMF to release all these PDU Sessions locally.

[0472] *****Next Change*****

[0473] 5.6.1.4 Service request process accepted by the network

[0474] For cases other than h) or k) in subclause 5.6.1.1, the UE shall regard the reception of the SERVICE ACCEPT message as successful completion of the procedure. The UE shall reset the SERVICE REQUEST ATTEMPT counter, stop timer T3517 and enter state 5GMM REGISTERED.

[0475] For cases h) and k) in subclause 5.6.1.1, the UE shall regard the indication from lower layers when the UE has changed to S1 mode or connected to E-UTRA of 5GCN (see 3GPP TS 23.502 [9]) as successful completion of the procedure and stop timer T3517.

[0476] If the AMF needs to initiate PDU Session State synchronization or the PDU Session State IE is included in the "Service Request" message, the AMF shall include the PDU Session State IE in the "Service Accept" message to indicate which PDU Sessions associated with the Access Type "Service Accept" message sent are active in the AMF. If the PDU Session State information element is included in the "Service Accept" message, the UE shall locally (without peer signaling between the network and the UE) release all those PDU Sessions that were active on the UE side associated with the Access Type "Service Accept" message sent, but were indicated as inactive by the AMF.

[0477] If the Uplink Data Status IE is included in the SERVICE REQUEST message, the AMF shall:

[0478] a) instruct the SMF to re-establish the user plane resources for the corresponding PDU session;

[0479] b) Include the PDU Session Reactivation Result IE in the "SERVICE ACCEPT" message to indicate the result of the user plane resource reactivation of the PDU session for which the UE requested re-establishment;

[0480] c) if the corresponding PDU session is a PDU session for LADN, determining that the UE in the LADN service area exists and forwarding the UE in the LADN service area to the SMF; and

[0481] d) If the corresponding PDU Session is a PDU Session of LADN and the SMF indicates to the AMF that the UE is outside the LADN service area, cause #43 "LADN Unavailable" is included to indicate in the PDU Session Reactivation Result Error Cause IE of the "SERVICE ACCEPT" message that the user plane resources for the PDU Session are not established.

[0482] If the Allowed PDU Session Status IE is included in the Service Request message, the AMF shall:

[0483] a) instruct the SMF to re-establish the user plane resources for the corresponding PDU session that is allowed to be re-established over 3GPP access and, in case there is at least one PDU session that can be re-established over 3GPP access indicated in the Allowed PDU Session Status IE, indicate pending downlink data;

[0484] b) inform the SMF that pending downlink data has been indicated and that reactivation of user plane resources for the corresponding PDU session cannot be performed if re-establishment via 3GPP access is not allowed; and

[0485] c) Include the PDU Session Reactivation Result IE in the SERVICE ACCEPT message to indicate the successful re-establishment of user plane resources (if any) for the corresponding PDU Session.

[0486] If the AMF has included the PDU Session Reactivation Result IE in the SERVICE ACCEPT message and there are one or more PDU Sessions for which user plane resources could not be re-established, the AMF may include a PDU Session Reactivation Result Error Cause IE to indicate the reason why user plane resources could not be re-established.

[0487] If user plane resources cannot be established for a PDU Session due to unavailable resources in the UPF as described in subclause 4.2.3.2 of 3GPP TS 23.502 [9], the AMF shall include in the SERVICE ACCEPT message a PDU SESSION REACTIVATION RESULTS IE indicating that user plane resources for the corresponding PDU Session could not be reestablished and shall include a PDU SESSION REACTIVATION RESULTS ERROR CAUSE IE with the 5GMM Cause set to #92 “Insufficient user plane resources for the PDU Session”.

[0488] NOTE: After receiving the PDU Session Reactivation Result Error Cause IE with the 5GMM Cause set to #92 "Insufficient User Plane Resources for PDU Session", it is up to the UE implementation when to resend the request for user plane re-establishment for the associated PDU Session.

[0489] If the SERVICE REQUEST message is for emergency services fallback, the AMF triggers the emergency services fallback procedure as specified in subclause 4.13.4.2 of 3GPP TS 23.502 [9].

[0490] Fig.15 A schematic diagram showing a diagram of a method of performing a registration request procedure that may be incorporated into 3GPP TS 24.501 (eg, in section 5.5.1.3.2).

[0491] Fig.16 A schematic diagram showing a diagram of a method of performing a service request procedure that may be incorporated into 3GPP TS 24.501 (eg, in section 5.6.1.1).

[0492] It is noted that while the above describes exemplifying embodiments, there are numerous variations and modifications which may be made to the disclosed solution without departing from the scope of the present invention.

[0493] The embodiments may therefore vary within the scope of the appended claims. In general, some embodiments may be implemented in hardware or dedicated circuits, software, logic, or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software that may be executed by a controller, microprocessor, or other computing device, but the embodiments are not limited thereto. Although various embodiments may be shown and described as block diagrams, flow charts, or shown and described using some other graphical representations, it should be understood that, as non-limiting examples, these boxes, devices, systems, techniques, or methods described herein may be implemented in hardware, software, firmware, dedicated circuits or logic, general hardware or controllers or other computing devices, or some combination thereof.

[0494] The embodiments may be implemented by computer software stored in a memory and executable by at least one data processor of the entity involved or by hardware or by a combination of software and hardware. Furthermore, in this regard, it should be noted that, for example, Figures 6 to 13 Any process in the software may represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, blocks and functions. The software may be stored on physical media such as memory chips or memory blocks implemented within a processor, magnetic media such as hard disk or floppy disks, and optical media such as DVDs and their data variants, CDs.

[0495] The memory may be of any type suitable for the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. The data processor may be of any type suitable for the local technical environment and may include, as non-limiting examples, one or more of the following: a general purpose computer, a special purpose computer, a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a gate level circuit, and a processor based on a multi-core processor architecture.

[0496] Alternatively or additionally, some embodiments may be implemented using circuits. The circuits may be configured to perform one or more of the previously described functions and / or method steps. The circuits may be provided in a base station and / or in a communication device.

[0497] As used in this application, the term "circuitry" may refer to one or more or all of the following:

[0498] (a) Pure hardware circuit implementation (such as implementation in analog and / or digital circuits only);

[0499] (b) A combination of hardware circuits and software, such as:

[0500] (i) a combination of analog and / or digital hardware circuitry and software / firmware, and

[0501] (ii) any portion of a hardware processor with software (including a digital signal processor), software and memory that work together to cause an apparatus (such as a communication device or base station) to perform the various functions previously described; and

[0502] (c) Hardware circuits and / or processors, such as a microprocessor or portion of a microprocessor, that require software (e.g., firmware) to operate, but the software may not be present when not required to operate.

[0503] This definition of circuitry applies to all uses of this term in this application, including in any claims. As another example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or a portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example, an integrated device.

[0504] The foregoing description has provided a comprehensive and informative description of some embodiments by way of illustrative examples and non-limiting examples. However, various modifications and alterations may become apparent to those skilled in the art in view of the foregoing description when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings will still fall within the scope as defined by the appended claims.

Claims

1. A device for invoking a service request process, the device include: at least one processor; as well as at least one memory storing instructions that, when executed by the at least one processor, cause the device to at least: In response to receiving a fallback indication from the radio resource control layer, When the device has no pending non-access stratum procedure and the device has pending uplink user data: Invoke the service request process; Setting an uplink data status information element IE in the service request message to indicate one or more packet data unit (PDU) sessions that were active on the user plane resources before receiving the fallback indication; and If the uplink data status IE indicates an emergency PDU session, the service type information element in the service request message is set to "emergency service", or if the uplink data status IE does not indicate an emergency PDU session, the service type information element in the service request message is set to "data", When the device has a pending non-access stratum procedure other than a registration procedure, a service request procedure, or a deregistration procedure: Invoking the service request process; as well as If the message for the pending non-access layer process is an uplink non-access layer transmission message including a request type IE set to "initial emergency request" or "existing emergency PDU session", the service type IE in the service request message is set to "emergency service", or in other cases the service type IE in the service request message is set to "signaling".

2. The apparatus of claim 1 , wherein the instructions, when executed by the at least one processor, cause the apparatus to at least: It is determined that the device has pending uplink user data and no pending non-access stratum procedures.

3. The apparatus of claim 1 , wherein the instructions, when executed by the at least one processor, cause the apparatus to at least: When the device in connected mode has the pending non-access layer procedure other than the service request procedure, setting the uplink data status IE in the service request message to indicate one or more PDU sessions that were active on user plane resources before receiving the fallback indication.

4. The apparatus of claim 1 , wherein the instructions, when executed by the at least one processor, cause the apparatus to at least: When the device in connected inactive mode has the pending non-access layer procedure other than the service request procedure, the uplink data status IE in the service request message is set to indicate one or more always-on PDU sessions.

5. The apparatus of claim 1 , wherein the instructions, when executed by the at least one processor, cause the apparatus to at least: It is determined that the device has the pending non-access stratum procedure other than the registration procedure, the service request procedure, or the deregistration procedure.

6. The apparatus of claim 1, wherein the instructions, when executed by the at least one processor, cause the apparatus to at least: In response to receiving the backoff indication, When the device has a pending service request procedure invoked due to non-emergency service fallback: Invoking the service request process; and If the device has the pending service request process due to non-emergency service fallback, the service type IE in the service request message is set to "mobile terminated service", "high priority access", "emergency service", or "data".

7. The apparatus of claim 6, wherein the instructions, when executed by the at least one processor, cause the apparatus to at least: When the device has the pending service request process invoked due to the non-emergency service fallback, the uplink data status IE in the service request message is set to indicate one or more PDU sessions, for which user plane resources were not active before receiving the fallback indication and the device has pending user data to be sent over the cellular network.

8. The apparatus of claim 6, wherein the instructions, when executed by the at least one processor, cause the apparatus to at least: It is determined that the device has the pending service request process invoked due to the non-emergency service fallback.

9. The apparatus of claim 1, wherein the instructions, when executed by the at least one processor, cause the apparatus to at least: In response to receiving the backoff indication, When the device has a pending service request procedure invoked due to emergency service fallback: Invoking the service request process; and If the device has the pending service request process due to the emergency service fallback, the service type IE in the service request message is set to "emergency service fallback".

10. The device of claim 1, wherein the device comprises user equipment.

11. The device of claim 1, wherein the device is in a connected mode.

12. The device of claim 1, wherein the device is in a connected inactive mode.

13. The apparatus of claim 1, wherein at least one of the following is performed at a non-access layer layer: the receiving, the calling, and the setting.

14. A method performed by a device, the method include: In response to receiving a fallback indication from the radio resource control layer, When the device has no pending non-access stratum procedure and the device has pending uplink user data: Invoke the service request process; Setting an uplink data status information element IE in the service request message to indicate one or more packet data unit (PDU) sessions that were active on the user plane resources before receiving the fallback indication; as well as If the uplink data status IE indicates an emergency PDU session, the service type information element in the service request message is set to "emergency service", or if the uplink data status IE does not indicate an emergency PDU session, the service type information element in the service request message is set to "data", When the device has a pending non-access stratum procedure other than a registration procedure, a service request procedure, or a deregistration procedure: Invoking the service request process; as well as If the message for the pending non-access layer process is an uplink non-access layer transmission message including a request type IE set to "initial emergency request" or "existing emergency PDU session", the service type IE in the service request message is set to "emergency service", or in other cases the service type IE in the service request message is set to "signaling".

15. The method of claim 14, wherein include: It is determined that the device has pending uplink user data and no pending non-access stratum procedures.

16. The method of claim 14, wherein include: When the device in connected mode has the pending non-access layer procedure other than the service request procedure, setting the uplink data status IE in the service request message to indicate one or more PDU sessions that were active on user plane resources before receiving the fallback indication.

17. The method of claim 14, wherein include: When the device in connected inactive mode has the pending non-access layer procedure other than the service request procedure, the uplink data status IE in the service request message is set to indicate one or more always-on PDU sessions.

18. The method of claim 14, wherein include: It is determined that the device has the pending non-access stratum procedure other than the registration procedure, the service request procedure, or the deregistration procedure.

19. The method of claim 14, wherein include: In response to receiving the backoff indication, When the device has a pending service request procedure invoked due to non-emergency service fallback: Invoking the service request process; as well as If the device has the pending service request process due to non-emergency service fallback, the service type IE in the service request message is set to "mobile terminated service", "high priority access", "emergency service", or "data".

20. The method of claim 19, wherein include: When the device has the pending service request process invoked due to the non-emergency service fallback, the uplink data status IE in the service request message is set to indicate one or more PDU sessions, for which user plane resources were not active before receiving the fallback indication and the device has pending user data to be sent over the cellular network.

21. The method of claim 19, wherein include: It is determined that the device has the pending service request process invoked due to the non-emergency service fallback.

22. The method of claim 19, wherein include: In response to receiving the backoff indication, When the device has a pending service request procedure invoked due to emergency service fallback: Invoking the service request process; as well as If the device has the pending service request process due to the emergency service fallback, the service type IE in the service request message is set to "emergency service fallback".

23. The method of claim 14, wherein the device comprises user equipment.

24. The method of claim 14, wherein the device is in a connected mode.

25. The method of claim 14, wherein the device is in a connected inactive mode.

26. The method of claim 14, wherein at least one of the following is performed at a non-access layer layer: the receiving, the calling, and the setting.

27. A non-transitory computer readable medium comprising computer executable instructions that when executed on one or more processors perform the steps of the method of claim 14.

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