Apparatus, method and computer program

Abstract

A user device, method and computer program are provided herein. The user equipment comprises at least one processor; and at least one memory including computer program code that, when executed by the at least one processor, causes the user device to at least: receive a fallback indication; calling a service request process; and setting a service type information element in the service request message.

Description

[0001] This application is a divisional application of a patent application for invention with international application number PCT / EP2018 / 081140, international filing date November 14, 2018, date of entry into the Chinese national phase April 20, 2021, and Chinese national application number 201880098853.X. Technical Field

[0002] The present disclosure relates to an apparatus, a method, and a computer program for invoking a service request process. Background Art

[0003] A communication system may be regarded as a facility for realizing a communication session between two or more entities (such as user terminals, base stations / access points, and / or other nodes) by providing a carrier wave between various entities involved in a 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, communication for carrying data for communication (such as voice, email, text messages, multimedia, and / or content data, etc.). Non-limiting examples of the services provided include two-way or multi-way calls, data communication, or multimedia services, and access to a data network system (such as the Internet). In a wireless communication system, at least a part of a communication session between at least two stations occurs via a wireless link.

[0004] A user may access a communication system by means of a suitable communication device or terminal. A user's communication device is often referred to as a user equipment (UE) or user device. The communication device has suitable signal receiving and transmitting equipment for realizing communication (such as realizing access to a communication network and / or direct communication with other users). The communication device may access a carrier wave provided by a station or access point and transmit and / or receive communication on the carrier wave.

[0005] Communication systems and associated devices generally operate according to a given standard or specification, which sets forth what the various entities associated with the system are permitted to do and how it should be achieved. Communication protocols and / or parameters that should be used for connections are also typically defined. An example of a communication system is UTRAN (3G radio). Another example of an architecture is 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

[0006] According to one aspect, there is provided an apparatus comprising at least one processor and at least one memory, the at least one memory including computer code for one or more programs, the at least one memory and the computer code being configured to, with the at least one processor, cause the apparatus to at least: 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.

[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 no outstanding non-access stratum procedures, (j) that the user equipment has an outstanding service request procedure due to a reason different from a predetermined reason, (k) that the user equipment has an outstanding service request procedure due to the predetermined reason, or (l) that the user equipment has an outstanding non-access stratum procedure other than a service request procedure; and invoke the service request procedure based on the determination.

[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 (i) that the user equipment has outstanding uplink user data and no outstanding non-access stratum procedures.

[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 (j) that the user equipment has an outstanding service request procedure invoked due to non-emergency service fallback.

[0010] 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 an outstanding service request procedure invoked by

[0011] due to emergency service fallback.

[0012] 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 (l) that the user equipment has an outstanding non-access stratum procedure other than a registration procedure, a service request procedure, or a deregistration procedure.

[0013] The user equipment may be in a connected mode.

[0014] The user equipment may be in a connected-inactive mode.

[0015] 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: set the service type information element in the service request message depending on the determination.

[0016] 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 stratum procedures, set the service type information element in the service request message to 'high priority access', 'emergency service', or 'data'.

[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 (j) the user equipment has a pending service request procedure for 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'.

[0018] 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 (k) the user equipment has a pending service request procedure for a predetermined reason, set the service type information element in the service request message to 'emergency service fallback'.

[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 (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'signaling'.

[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: set the uplink data status information element in the service request message based on the determination.

[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 (i) the user equipment has no pending non-access stratum procedures, set the uplink data status information element in the service request message to indicate a packet data unit session in which user plane resources were active prior to invocation of the service request procedure.

[0022] The at least one memory and the computer program code may be configured to, with the at least one processor, cause the device to at least: when (j) the user equipment has a pending service request procedure 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 in which user plane resources were active before invoking the service request procedure and / or a packet data unit session in which user plane resources were inactive before receiving the fallback indication and the user equipment has pending user data to be sent over the cellular network.

[0023] The at least one memory and the computer program code may be configured to, with the at least one processor, cause the device to at least: when (l) the user equipment in the connected mode has a pending non-access stratum 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 in which user plane resources were active before invoking the service request procedure.

[0024] The at least one memory and the computer program code may be configured to, 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 stratum procedure other than a service request procedure, set the uplink data status information element in the service request message to indicate an always-on packet data unit session.

[0025] At least one of the receiving, the determining, the invoking, and the setting may be performed at the non-access stratum layer.

[0026] According to one aspect, there is provided a device, the device including circuitry configured to perform the following operations: 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.

[0027] The circuitry may be configured to: determine (i) that the user equipment has no pending non-access stratum procedure, (j) that the user equipment has a pending service request procedure due to a reason different from a predetermined reason, (k) that the user equipment has a pending service request procedure due to the predetermined reason, or (l) that the user equipment has a pending non-access stratum procedure other than a service request procedure; and invoke the service request procedure based on the determination.

[0028] The circuitry may be configured to: determine (i) that the user equipment has pending uplink user data and no pending non-access stratum procedure.

[0029] The circuit may be configured to: determine (j) that the user equipment has a pending service request procedure invoked due to non-emergency service fallback.

[0030] The circuit may be configured to: determine (k) that the user equipment has a pending service request procedure invoked due to emergency service fallback.

[0031] The circuit may be configured to: (l) that the user equipment has a pending non-access stratum procedure other than a registration procedure, a service request procedure, or a deregistration procedure.

[0032] The user equipment may be in the connected mode.

[0033] The user equipment may be in the connected inactive mode.

[0034] The circuit may be configured to: set the service type information element in the service request message depending on the determination.

[0035] 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'.

[0036] The circuit may be configured to: when (j) the user equipment has a pending service request procedure 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'.

[0037] 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'.

[0038] 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'signaling'.

[0039] The circuit may be configured to: set the uplink data status information element in the service request message based on the determination.

[0040] The circuit may be configured to: when (i) the user equipment has no pending non-access stratum procedure, set the uplink data status information element in the service request message to indicate that the user plane resources are in an active packet data unit session before invoking the service request procedure.

[0041] The circuit may be configured to: when (j) the user equipment has a pending service request procedure for 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 in which the user plane resource was active before invoking the service request procedure and / or a packet data unit session in which the user plane resource was inactive before receiving the fallback indication and the user equipment has pending user data to be sent over the cellular network.

[0042] The circuit may be configured to: when (l) the user equipment in the connected mode has a pending non-access stratum procedure other than the service request procedure, set the uplink data status information element in the service request message to indicate a packet data unit session in which the user plane resource was active before invoking the service request procedure.

[0043] The circuit may be configured to: when (l) the user equipment in the connected-inactive mode has a pending non-access stratum procedure other than the service request procedure, set the uplink data status information element in the service request message to indicate an always-on packet data unit session.

[0044] At least one of the receiving, the determining, the invoking, and the setting may be performed at the non-access stratum layer.

[0045] According to one 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.

[0046] The method may comprise: determining (i) that the user equipment has no pending non-access stratum procedure, (j) that the user equipment has a pending service request procedure for a reason different from a predetermined reason, (k) that the user equipment has a pending service request procedure due to the predetermined reason, or (l) that the user equipment has a pending non-access stratum procedure other than the service request procedure; and invoking the service request procedure based on the determination.

[0047] The method may comprise: determining (i) that the user equipment has pending uplink user data and no pending non-access stratum procedure.

[0048] The method may comprise: determining (j) that the user equipment has a pending service request procedure invoked due to non-emergency service fallback.

[0049] The method may include: determining (k) that the user equipment has a pending service request procedure invoked due to emergency service fallback.

[0050] The method may include: determining (l) that the user equipment has a pending non-access stratum procedure other than a registration procedure, a service request procedure, or a deregistration procedure.

[0051] The user equipment may be in a connected mode.

[0052] The user equipment may be in a connected-inactive mode.

[0053] The method may include: setting the service type information element in the service request message depending on the determination.

[0054] 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'.

[0055] The method may include: when (j) the user equipment has a pending service request procedure 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'.

[0056] 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'.

[0057] 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'.

[0058] The method may include: setting the uplink data status information element in the service request message based on the determination.

[0059] The method may include: when (i) the user equipment has no pending non-access stratum procedure, setting the uplink data status information element in the service request message to indicate that the user plane resources are in an active packet data unit session before invoking the service request procedure.

[0060] 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 in which user plane resources are active before invoking the service request procedure and / or a packet data unit session in which user plane resources are inactive before receiving the fallback indication and the user equipment has pending user data to be sent via the cellular network.

[0061] The method may include: when (l) the user equipment in the connected mode has a pending non-access stratum procedure other than the service request procedure, setting the uplink data status information element in the service request message to indicate a packet data unit session in which user plane resources are active before invoking the service request procedure.

[0062] The method may include: when (l) the user equipment in the connected-inactive mode has a pending non-access stratum procedure other than the service request procedure, setting the uplink data status information element in the service request message to indicate an always-on packet data unit session.

[0063] At least one of the receiving, the determining, the invoking, and the setting may be performed at the non-access stratum layer.

[0064] According to one aspect, there is provided a computer program comprising computer-executable code which, when run 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.

[0065] The computer program includes computer-executable code which, when run on at least one processor, may be configured to: determine (i) that the user equipment has no pending non-access stratum procedure, (j) that the user equipment has a pending service request procedure due to a reason different from a predetermined reason, (k) that the user equipment has a pending service request procedure due to the predetermined reason, or (l) that the user equipment has a pending non-access stratum procedure other than the service request procedure; and invoke the service request procedure based on the determination.

[0066] The computer program includes computer-executable code which, when run on at least one processor, may be configured to: determine (i) that the user equipment has pending uplink user data and no pending non-access stratum procedure.

[0067] The computer program includes computer-executable code which, when run on at least one processor, can be configured to: determine (j) that the user equipment has a pending service request procedure invoked due to non-emergency service fallback.

[0068] The computer program includes computer-executable code which, when run on at least one processor, can be configured to: determine (k) that the user equipment has a pending service request procedure invoked due to emergency service fallback.

[0069] The computer program includes computer-executable code which, when run on at least one processor, can be configured to: determine (l) that the user equipment has a pending non-access stratum procedure other than a registration procedure, a service request procedure, or a deregistration procedure.

[0070] The user equipment may be in a connected mode.

[0071] The user equipment may be in a connected-inactive mode.

[0072] The computer program includes computer-executable code which, when run on at least one processor, can be configured to: set the service type information element in the service request message depending on the determination.

[0073] The computer program includes computer-executable code which, when run on at least one processor, can 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'.

[0074] The computer program includes computer-executable code which, when run on at least one processor, can 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 service type information element in the service request message to'mobile terminated service', 'high priority access', 'emergency service', or 'data'.

[0075] The computer program includes computer-executable code which, when run on at least one processor, can 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'.

[0076] The computer program includes computer-executable code that, when run on at least one processor, can be configured to: when (l) the user equipment has a pending non-access stratum process 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'.

[0077] The computer program includes computer-executable code that, when run on at least one processor, can be configured to: based on the determination, set the uplink data status information element in the service request message.

[0078] The computer program includes computer-executable code that, when run on at least one processor, can be configured to: when (i) the user equipment has no pending non-access stratum process, set the uplink data status information element in the service request message to indicate a packet data unit session in which the user plane resources were active before invoking the service request procedure.

[0079] The computer program includes computer-executable code that, when run on at least one processor, can be configured to: when (j) the user equipment has a pending service request procedure for 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 in which the user plane resources were active before invoking the service request procedure and / or a packet data unit session in which the user plane resources were inactive before receiving the fallback indication and the user equipment has pending user data to be sent over the cellular network.

[0080] The computer program includes computer-executable code that, when run on at least one processor, can be configured to: when (l) the user equipment in the connected mode has a pending non-access stratum process 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 in which the user plane resources were active before invoking the service request procedure.

[0081] The computer program includes computer-executable code that, when run on at least one processor, can be configured to: when (l) the user equipment in the connected-inactive mode has a pending non-access stratum process other than a service request procedure, set the uplink data status information element in the service request message to indicate an always-on packet data unit session.

[0082] At least one of the receiving, the determining, the invoking, and the setting may be performed at the non-access stratum.

[0083] According to one aspect, there is provided a computer-readable medium including program instructions stored thereon for performing at least one of the above methods.

[0084] According to one aspect, there is provided a non-transitory computer-readable medium including program instructions stored thereon for performing at least one of the above methods.

[0085] According to one aspect, there is provided a non-volatile tangible memory medium including program instructions stored thereon for performing at least one of the above methods.

[0086] Above, many different aspects have been described. It should be understood that additional aspects may be provided by any combination of two or more of the above aspects.

[0087] Various other aspects are also described in the following detailed description and the appended claims.

[0088] Abbreviation:

[0089] AS: Access Stratum

[0090] AMF: Access Management Function

[0091] CN: Core Network

[0092] DNN: Data Network Name

[0093] DRX: Discontinuous Reception

[0094] EMM: EPS Mobility Management

[0095] eNB: Evolved Node B

[0096] EPS: Evolved Packet System

[0097] EPC: Evolved Packet Core

[0098] ESFB: Emergency Service Fallback

[0099] E-UTRA: Evolved Universal Terrestrial Radio Access

[0100] gNB: Next Generation Node B

[0101] GSM: Global System for Mobile Communications

[0102] GUTI: Globally Unique Temporary UE Identity

[0103] HO: Handover

[0104] ID: Identifier

[0105] IE: Information Element

[0106] LTE: Long Term Evolution

[0107] LADN: Local Area Data Network

[0108] NB: Node B

[0109] NG: Next Generation

[0110] MAC: Media Access Control

[0111] MICO: Mobile Initiated Connection Only

[0112] MS: Mobile Station

[0113] MTC: Machine Type Communication

[0114] NAS: Non-Access Stratum

[0115] NSSAI: Network Slice Selection Assistance Information

[0116] PDA: Personal Digital Assistant

[0117] PDCP: Packet Data Convergence Protocol

[0118] PDU: Packet Data Unit

[0119] PDN: Packet Data Network

[0120] PHY: Physical

[0121] PLMN: Public Land Mobile Network

[0122] RAM: Random Access Memory

[0123] RAN: Radio Access Network

[0124] RAT: Radio Access Technology

[0125] RCU: Radio Control Unit

[0126] RLC: Radio Link Control

[0127] ROM: Read Only Memory

[0128] RRC: Radio Resource Control

[0129] SMS: Short Message Service

[0130] SMF: Session Management Function S-NSSAI: Single Network Slice Selection Assistance Information TAI: Tracking Area Identity

[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 USB: Universal Serial Bus

[0136] 3G: Third Generation

[0137] 3GPP: Third Generation Partnership Project

[0138] 4G: Fourth Generation

[0139] 5G: Fifth Generation

[0140] 5GS: 5G System 5GMM: 5G System Mobility Management Description of the Drawings

[0141] The embodiments will now be described by way of example only with reference to the accompanying drawings, in which:

[0142] Figure 1 A schematic diagram of a communication system is shown;

[0143] Figure 2 A schematic diagram of a control device is shown;

[0144] Figure 3 A schematic diagram of a user equipment is shown;

[0145] Figure 4 A schematic diagram of the control plane stack of a user equipment, a base station and a core network in a 5G system is shown;

[0146] Figure 5 A schematic diagram of the mobility management mode of a user equipment in a 5G system is shown;

[0147] Figure 6 A schematic diagram of a graph of a method for performing a service request procedure is shown;

[0148] Figure 7 A schematic diagram of a graph of a method for setting the uplink data status information element in a "service request" message when condition i) is met is shown;

[0149] Figure 8 Schematic diagram of a figure showing a method of setting a service type information element in a "service request" message when condition i) is satisfied;

[0150] Figure 9 Schematic diagram of a figure showing a method of setting an uplink data status information element in a "service request" message when condition j) is satisfied;

[0151] Figure 10 Schematic diagram of a figure showing a method of setting a service type information element in a "service request" message when condition j) is satisfied;

[0152] Figure 11 Schematic diagram of a figure showing a method of setting a service type information element in a "service request" message when condition k) is satisfied;

[0153] Figure 12 Schematic diagram of a figure showing a method of setting an uplink data status information element in a "service request" message when condition l) is satisfied;

[0154] Figure 13 Schematic diagram of a figure showing a method of setting a service type information element in a "service request" message when condition l) is satisfied;

[0155] Figure 14 Schematic diagram of a non - volatile memory medium storing instructions which, when executed by a processor, allow the processor to execute Figures 6 to 13 one or more steps of the methods of any of those in

[0156] Figure 15 Schematic diagram of a figure showing a method of performing a registration request procedure according to the proposed modification to 3GPP TS24.501;

[0157] Figure 16 Schematic diagram of a figure showing a method of performing a service request procedure according to the proposed modification to 3GPP TS24.501. Detailed implementation manners

[0158] 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. Before explaining the exemplary embodiments in detail, certain general principles of wireless communication systems, their access systems, and mobile communication devices are briefly explained to assist in understanding the underlying technology of the described examples. Figures 1 to 5 Certain general principles of wireless communication systems, their access systems, and mobile communication devices are briefly explained to assist in understanding the underlying technology of the described examples.

[0159] Figure 1An 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 transmitting and / or receiving nodes or points. The base stations can be evolved Node B (eNB), next-generation Node B (gNB), or others. The base stations 106 and 107 are generally controlled by at least one appropriate control device. The controller device can be part of the base stations 106 and 107.

[0160] The base stations 106 and 107 are connected to a wider communication network 113 via a gateway 112. Another gateway function can be provided to connect to another network.

[0161] The base stations 116, 118, and 120 associated with smaller cells can also be connected to the network 113, for example, through a separate gateway function and / or via a macro-level station. The base stations 116, 118, and 120 can be pico-level or femto-level base stations, and the like. In the example, the base stations 116 and 118 are connected via a gateway 111, while the base station 120 is connected via the base station 106. In some embodiments, the smaller base stations 116, 118, and 120 may not be provided.

[0162] Figure 2 An example of a control device 200 for a node is shown, which is, for example, integrated with, coupled to, or otherwise controls a base station, such as Figure 1 the base stations 106, 107, 116, 118, or 120 shown. The control device 200 can be arranged to allow communication between a user equipment and a 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. The at least one processor 212, 213 is coupled to the RAM 211a and the ROM 211b. Via the interface, the control device 200 can be coupled to other relevant components of the base station. The at least one processor 212, 213 can be configured to execute appropriate software code 215. The software code 215 can be stored in the ROM 211b. It should be understood that similar components can be provided in a control device located elsewhere in the network system (e.g., in a core network (CN) entity). The control device 200 can be interconnected with other control entities. The control device 200 and its functions can be distributed among multiple control units. In some embodiments, each base station can include a control device. In alternative embodiments, two or more base stations can share a control device.

[0163] The base station and the associated controller can communicate with each other via a fixed-line connection and / or via a radio interface. The logical connection between base stations can be provided, for example, through an X2 or similar interface. This interface can be used, for example, to coordinate the operation of the base stations and perform reselection or handover operations.

[0164] Figure 3 An example of a user equipment or wireless communication device 300 (such as Figure 1 the wireless communication devices 102, 104, or 105 shown) is illustrated. The wireless communication device 300 can be provided by any device capable of sending and receiving radio signals. Non-limiting examples include a mobile station (MS) or a mobile device (such as a mobile phone or a so-called "smartphone"), a computer equipped 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 can provide, for example, communication for carrying data of the communication. The communication can be one or more of voice, email, text message, multimedia, data, machine data, etc.

[0165] The device 300 can receive signals via an appropriate device for reception over the air or a radio interface 307, and can transmit signals via an appropriate device for transmitting radio signals. In Figure 3 it, the transceiver device is schematically indicated by the block 306. The transceiver device 306 can be provided, for example, by means of a radio part and an associated antenna arrangement. The antenna arrangement can be disposed inside or outside the mobile device.

[0166] The wireless communication device 300 can include at least one processor 301, at least one memory ROM 302a, at least one RAM 302b, and other possible components 303 for use in the software and hardware-assisted execution of the tasks it is designed to perform, which tasks include controlling access to the access system and other communication devices and communicating with the access system and other communication devices. At least one processor 301 is coupled to the RAM 211a and the ROM 211b. At least one processor 301 can be configured to, for example, execute appropriate software code 308 to perform Figures 6 to 15 any one of the methods in

[0167] The processor, storage device, and other related control devices can be provided on a suitable circuit board and / or in a chipset. This feature is indicated by the reference numeral 304. The device can 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 can be provided depending on the type of the device.

[0168] Figure 4 A schematic diagram showing the control plane stacks of a UE, a gNB, and a CN in a 5G system is presented.

[0169] 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 Stratum (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.

[0170] Each layer of the UE, gNB, and CN may include one of multiple functions that perform one or more processes.

[0171] Figure 5 A schematic diagram of the state machine of a UE in a 5G system is presented. The state machine includes various 5G system mobility management (5GMM) modes, such as an idle mode (e.g., "5GMM idle" mode), a connected mode (e.g., "5GMM connected" mode), and a connected inactive mode (e.g., "5GMM connected" mode with an RRC inactive indication).

[0172] The idle mode and the connected mode may be available via 3GPP access or non-3GPP access. The connected inactive mode is only available via 3GPP access.

[0173] 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.

[0174] After power-on, the UE may enter the idle mode. The UE may also enter the idle mode from the connected mode or the connected inactive mode.

[0175] In the connected mode, the UE may be connected to a 5G Radio Access Network (RAN) and a 5G Core Network (CN). The UE may also enter the connected mode from the idle mode or the connected inactive mode.

[0176] 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 the connected mode. When there is a NAS signaling connection but the underlying access stratum connection is suspended, the UE may be in the connected inactive mode; otherwise, in the "5GMM idle" mode.

[0177] The UE can further be in a registered state (e.g., "5GMM registered" state) and a deregistered state (e.g., "5GMM deregistered" state). When the UE successfully registers to the 5G system, the UE can enter the registered state. Otherwise, the UE can be in the deregistered state. The UE can be in the registered state while being in the idle mode via 3GPP access, the connected mode via 3GPP access, or the connected inactive mode via 3GPP access.

[0178] In the connected mode, the UE can be connected to the 5G RAN and the 5G CN while minimizing signaling and power consumption.

[0179] One or more of the following examples relate to 3GPP TS24.501, which is a technical specification related to the NAS protocol of the 5G system. However, it will be understood that these examples can be transformed to different standards.

[0180] Similarly, one or more of the following examples relate to 5G. However, it will be understood that these examples can be transformed to different radio access technologies.

[0181] When the UE is in the "5GMM connected" mode via 3GPP access or in the "5GMM connected" mode with an RRC inactivity indication, the UE NAS layer can receive a fallback indication from the lower layer (i.e., the RRC layer). When the UE RRC layer receives an "RRC setup" message from the gNB in response to the following, the UE RRC layer can send a fallback indication to the UE NAS layer:

[0182] - An "RRC reestablishment request" message sent by the UE in the "5GMM connected" mode via 3GPP access; or

[0183] - An RRC resume request message sent by the UE in the "5GMM connected" mode with an RRC inactivity indication.

[0184] Generally, after receiving the fallback indication, the UE NAS layer initiates a NAS procedure. Other details regarding the behavior of the UE after receiving the fallback indication can vary according to the following:

[0185] - The mode of the UE when the UE receives the fallback indication;

[0186] - The presence of pending uplink user data; and

[0187] - The presence and type of pending NAS procedures.

[0188] The NAS procedures may refer to the registration procedure, service request procedure, deregistration procedure, notification procedure, paging procedure, NAS transfer procedure, 5GMM status procedure, primary authentication and key negotiation procedure, security mode control procedure, identification procedure, general UE configuration update procedure, or other procedures.

[0189] According to 3GPP TS24.501, 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 TS24.501 further describes that in some cases, the uplink (UL) data status IE in the "registration request" or "service request" message may indicate a PDU session for which the user plane resources are active before receiving a fallback indication.

[0190] The disadvantage of 3GPP TS24.501 is that it incorrectly describes or ignores various 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 TS24.501 does not describe at all the setting of the service type information element (IE) in the "service request" message and incompletely describes the setting of the UL data status IE in the "service request" message or the "registration request" message.

[0191] One or more of the following examples address the deficiencies of 3GPP TS24.501 (in section 5.6.1.1 of 3GPP TS24.501) by supplementing the existing situations a), b), c), d), e), f), g), and h) that are not related to the fallback indication from the lower layer, while situations i), j), k), and l) deal with the service request procedure initiated after receiving a fallback indication from the lower layer.

[0192] In situation i), the UE may be in the connected mode via 3GPP access or in the 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 without having any pending NAS procedures.

[0193] In situation j), the UE may be in the connected mode via 3GPP access or in the 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).

[0194] For example, a pending service request procedure may have been invoked because the UE received a notification message via 3GPP access with an access type IE indicating non-3GPP access.

[0195] Alternatively, the pending service request procedure may have been invoked because the UE in the connected mode or in the connected inactive mode has pending user data due to the non-user plane resources established for the PDU session for user data transmission.

[0196] In case k), the UE may be in the connected mode via 3GPP access or in the 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.

[0197] In case l), the UE may be in the connected mode via 3GPP access or in the connected inactive mode. The NAS layer function may receive a fallback indication from the RRC layer function. The UE may have a pending NAS procedure other than a registration, service request, or deregistration procedure.

[0198] One or more of the following examples address other deficiencies in 3GPP TS 24.501 by setting the service type IE in the "Service Request" message as described below.

[0199] When case i) is satisfied, the service type IE in the "Service Request" may be set to 'High Priority Access', 'Emergency Service', or 'Data'.

[0200] When case j) is satisfied, the service type IE in the "Service Request" may be set to 'MT Service', 'High Priority Access', 'Emergency Service', or 'Data'.

[0201] When case k) is satisfied, the service type IE in the "Service Request" may be set to 'ESFB'.

[0202] When case l) is satisfied, the service type IE in the "Service Request" may be set to 'Emergency Service', 'High Priority Access', or 'Signaling'.

[0203] One or more of the following examples further address the deficiencies in 3GPP TS 24.501 by setting the UL data status IE in the "Service Request" as described below.

[0204] When case i) is satisfied, the UL data status IE in the "Service Request" may indicate the PDU sessions for which the user plane resources were active before receiving the fallback indication.

[0205] When condition j) is satisfied, the UL data status IE in the "Service Request" may indicate the PDU session(s) (if any) for which the user plane resources were active before receiving the fallback indication and / or the PDU session(s) (if any) for which the user plane resources were inactive before receiving the fallback indication and the UE has pending user data to be sent via 3GPP access.

[0206] When condition k) is satisfied, the UL data status IE in the "Service Request" may not be specified.

[0207] When condition l) is satisfied, when the UE is in the connected mode, the UL data status IE in the "Service Request" may indicate the PDU session(s) (if any) for which the user plane resources were active before receiving the fallback indication. If the UE does not have always-on PDU sessions, when the UE is in the connected inactive mode, the UL data status IE may not be included in the "Service Request" message. If a UE in the 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 UE mode (i.e., connected mode or connected inactive mode), the UL data status IE in the "Service Request" may indicate the PDU session(s) (if any) for which the user plane resources were active before receiving the fallback indication.

[0208] 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.

[0209] The following example resolves the defect in 3GPP TS 24.501 by setting the UL data status IE in the "Registration Request" message as described below:

[0210] The UE may be in the connected mode via 3GPP access or in the 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 session(s) (if any) for which the user plane resources were active before receiving the fallback indication and / or the PDU session(s) (if any) for which the user plane resources were inactive before receiving the fallback indication and the UE has pending user data to be sent via 3GPP access.

[0211] Figure 6Schematic diagram of a figure showing a method for performing a service request procedure. The method can be performed by a UE and more specifically by NAS layer functionality.

[0212] In step 602, the NAS layer functionality of the UE can determine that one of cases i), j), k), or l) for invoking the service request procedure is satisfied.

[0213] In step 604, the NAS layer functionality of the UE can invoke the service request procedure.

[0214] In step 606, the NAS layer functionality of the UE can set the service type IE in the "Service Request" message depending on the satisfied case. That is, when case i), j), k), or l) is satisfied, the NAS layer functionality of the UE can set the service type IE in the "Service Request" message differently. This step will be discussed in more detail with reference to Figure 8 , Figure 9 , Figure 11 and Figure 13 more specifically.

[0215] In step 608, the NAS layer functionality of the UE can set the UL data status IE in the "Service Request" message depending on the satisfied case. That is, when case i), j), k), or l) is satisfied, the NAS layer functionality of the UE can set the UL data status IE in the "Service Request" message differently. This step will be discussed in more detail with reference to Figure 7 , Figure 10 and Figure 12 more specifically.

[0216] In step 610, the NAS layer functionality of the UE can send the "Service Request" message to the NAS layer functionality of the CN. The NAS layer functionality of the CN can be the Access Management Function (AMF). The NAS layer functionality of the UE can start a service request retransmission timer (e.g., T3517). The NAS layer functionality of the UE can increment the service request attempt counter.

[0217] In step 612, the NAS layer functionality of the UE can determine that the service request procedure has been completed. The determination can depend on the satisfied case.

[0218] For example, when one of cases i), j), or k) is satisfied, after receiving a "Service Accepted" message from the NAS layer functionality of the CN, the NAS layer functionality of the UE can determine that the service request procedure has been completed. The NAS layer functionality of the UE can then stop the service request retransmission timer and can reset the service request attempt counter.

[0219] Alternatively, when condition l) is met, after receiving an indication from the RRC layer function of the UE that the UE has changed to S1 mode or is connected to the 5GCN via E-UTRA, the NAS layer function of the UE may determine that the service request procedure is complete. The NAS layer function of the UE may then stop the service request retransmission timer.

[0220] Figure 7 Schematic diagram of a figure showing a method of setting the UL data status IE in a "service request" message when condition i) is met. The method may be performed by the UE and more specifically by the NAS layer function.

[0221] In step 702, the NAS function of the UE may determine that condition i) is met. In particular, the NAS function of the UE may determine that the UE has pending UL user data and no pending NAS procedures.

[0222] In step 704, the NAS function of the UE may set the UL data status IE in the "service request" message to indicate a packet data unit (PDU) session for which user plane resources are active before receiving a fallback indication. The fallback indication may be received from the RRC layer function of the UE.

[0223] Figure 8 Schematic diagram of a figure showing a method of setting the service type IE in a "service request" message when condition i) is met. The method may be performed by the UE and more specifically by the NAS layer function.

[0224] In step 802, the NAS layer function of the UE may determine that condition i) is met. In particular, the NAS function of the UE may determine that the UE has pending UL user data and no pending NAS procedures.

[0225] 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.

[0226] In step 806 (i.e., 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'.

[0227] 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 can 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.

[0228] In step 810 (i.e., an emergency PDU session is indicated in the UL data status IE in the "Service Request" message), the NAS layer function of the UE can set the service type IE in the "Service Request" message to 'Emergency Service'.

[0229] In step 812 (i.e., an emergency PDU session is not indicated in the UL data status IE in the "Service Request" message), the NAS layer function of the UE can set the service type IE in the "Service Request" message to 'Data'.

[0230] Figure 9 A schematic diagram of a figure showing a method of setting the UL data status IE in the "Service Request" message when condition j) is met is shown. The method can be performed by the UE and more specifically by the NAS layer function.

[0231] In step 902, the NAS function of the UE can determine that condition j) is met. In particular, the NAS function of the UE can determine that the UE has a pending service request procedure invoked for a reason other than emergency service fallback (ESFB).

[0232] For example, a pending service request procedure may have been invoked because the UE received a notification message with an access type indicating non-3GPP access via 3GPP access.

[0233] Alternatively, the pending service request procedure may have been invoked because the UE in the connected mode or in the connected inactive mode has pending user data due to non-user plane resources established for a PDU session for user data transmission.

[0234] In step 904, the NAS function of the UE can set the UL data status IE in the "Service Request" message to indicate a PDU session in which the user plane resources were active before receiving a fallback indication from the RRC layer entity. Alternatively or additionally, the NAS function of the UE can set the UL data status IE in the "Service Request" message to indicate a PDU session in which the user plane resources were inactive before receiving the fallback indication and the UE has pending user data to be sent via 3GPP access (if any).

[0235] Figure 10 Schematic diagram of a figure showing a method of setting the service type IE in a "Service Request" message when condition j) is satisfied. The method can be performed by a UE and more specifically by the NAS layer function.

[0236] In step 1002, the NAS layer function of the UE can determine that condition j) is satisfied. In particular, the NAS function of the UE can determine that the UE has an outstanding service request procedure invoked for a reason other than ESFB.

[0237] If the outstanding service request procedure has been invoked because the UE has received a notification message with an access type indicating non-3GPP access via 3GPP access, the method proceeds to step 1004.

[0238] If the pending service request procedure has been invoked because user data is pending for a UE in connected mode or in connected-inactive mode due to non-user plane resources established for a PDU session for user data transmission, the method proceeds to step 1006.

[0239] In step 1004, that is, the outstanding service request procedure has been invoked because the UE has received a notification message with an access type indicating non-3GPP access via 3GPP access, the NAS layer function of the UE can set the service type IE in the "Service Request" message to'mobile terminated service'.

[0240] In step 1006 (i.e., the outstanding service request procedure has been invoked because user data is pending for a UE in connected mode due to non-user plane resources established for a PDU session for user data transmission), the NAS layer function of the UE can determine whether the UE is configured for high-priority access in the selected public land mobile network (PLMN).

[0241] 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.

[0242] In step 1008 (i.e., the UE is configured for high-priority access in the selected PLMN), the NAS layer function of the UE can set the service type IE in the "Service Request" message to 'high-priority access'.

[0243] In step 1010 (i.e., the UE is not configured for high-priority access in the selected PLMN), the NAS layer function of the UE can determine whether an emergency PDU session is indicated in the UL data status IE in the "Service Request" message.

[0244] If an emergency PDU session is indicated in the UL data status IE in the "Service Request" message, the method proceeds to step 1012. If an emergency PDU session is not indicated in the UL data status IE in the "Service Request" message, the method proceeds to step 1014.

[0245] In step 1012 (i.e., when an 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'.

[0246] In step 1014 (i.e., when an emergency PDU session is not 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'.

[0247] Alternatively or additionally, the NAS layer function of the UE may determine whether the allowed PDU session status IE is included in the "Service Request" message. For example, if the UE has invoked an outstanding service request procedure because the UE has received a notification message with an access type indicating non-3GPP access via 3GPP access, the NAS layer function of the UE may determine that the allowed PDU session status IE is included in the "Service Request" message.

[0248] The NAS layer function of the UE may then determine whether the UE has one or more PDU sessions associated with a single network slice selection assistance information (S-NSSAI) included in the allowed network slice selection assistance information (NSSAI) for 3GPP access via non-3GPP access, and the UE allows the user plane resources for the PDU sessions via non-3GPP access to be reconstructed via 3GPP access.

[0249] If the UE has one or more PDU sessions associated with the S-NSSAI included in the allowed NSSAI for 3GPP access via non-3GPP access, and the UE allows the user plane resources for the PDU sessions via non-3GPP access to be reconstructed via 3GPP access, the UE may set the allowed PDU session status IE to indicate one or more PDU sessions.

[0250] If the UE does not have a PDU session associated with the S-NSSAI included in the allowed NSSAI for 3GPP access via non-3GPP access, or the UE does not allow the user plane resources for the PDU sessions via non-3GPP access to be reconstructed via 3GPP access, the UE may set the allowed PDU session status IE to indicate no PDU sessions.

[0251] Figure 11Schematic diagram of a figure showing a method for setting the service type IE in a "Service Request" message when condition k) is met. The method can be performed by a user equipment and in particular by the NAS function.

[0252] In step 1102, the NAS function of the UE can determine that condition k) is met. In particular, the NAS function of the UE can determine that the UE has a pending service request procedure invoked due to emergency service fallback.

[0253] In step 1104, the NAS function of the UE can set the UL service type IE in the "Service Request" message to 'Emergency service fallback'.

[0254] Figure 12 Schematic diagram of a figure showing a method for setting the UL data status IE in a "Service Request" message when condition l) is met. The method can be performed by a user equipment and in particular by the NAS function.

[0255] In step 1202, the NAS function of the UE can determine that condition l) is met. In particular, the NAS function of the UE can determine that the UE has a pending NAS procedure other than a registration procedure, a service request procedure, or a deregistration procedure.

[0256] In step 1204, the NAS function of the UE can determine whether the UE is in the connected mode or in the connected-inactive mode. If the UE is in the connected mode, the method proceeds to 1206. If the UE is in the connected-inactive mode, the method proceeds to 1208.

[0257] In step 1206, the NAS function of the UE can set the UL data status IE in the "Service Request" message to indicate the PDU session (if any) for which the user plane resources were active before receiving the fallback indication. The fallback indication can be received from the RRC layer function of the UE.

[0258] In step 1208, the NAS function of the UE can 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.

[0259] Figure 13 Schematic diagram of a figure showing a method for setting the service type IE in a "Service Request" message when condition l) is met.

[0260] In step 1302, the NAS function of the UE can determine that condition l) is met. In particular, the NAS function of the UE can determine that the UE has a pending NAS procedure other than a registration procedure, a service request procedure, or a deregistration procedure.

[0261] In step 1304, the NAS layer function of the UE can determine whether the UE is configured for high-priority access in the selected public land mobile network (PLMN).

[0262] 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.

[0263] In step 1306 (i.e., the UE is configured for high-priority access in the selected PLMN), the NAS layer function of the UE can set the service type IE in the "service request" message to 'high-priority access'.

[0264] In step 1308 (i.e., the UE is not configured for high-priority access in the selected PLMN), the NAS layer function of the UE can determine whether there is a "UL NAS transport" message with the request type IE set to 'initial emergency request' or 'existing emergency PDU session'.

[0265] If there is a pending "UL NAS transport" 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 transport" message with the request type IE set to 'initial emergency request' or 'existing emergency PDU session', the method proceeds to step 1312.

[0266] In step 1310 (i.e., there is a pending "UL NAS transport" message with the request type IE set to 'initial emergency request' or 'existing emergency PDU session'), the NAS layer function of the UE can set the service type IE in the "service request" message to 'emergency service'.

[0267] In step 1312 (i.e., there is no pending "UL NAS transport" message with the request type IE set to 'initial emergency request' or 'existing emergency PDU session'), the NAS layer function of the UE can set the service type IE in the "service request" message to'signaling'.

[0268] Figure 14 A schematic diagram shows non-volatile memory media 1400a (e.g., a computer disk (CD) or a digital versatile disk (DVD)) and 1400b (e.g., a universal serial bus (USB) storage stick) storing instructions and / or parameters 1402, which, when executed by a processor, allow the processor to execute Figures 6 to 13 one or more steps of the method.

[0269] It will be understood that one or more of the above examples may be incorporated, for example, by combining one or more of the following sections, into a modified version of 3GPP TS 24.501.

[0270] 5.3.1.2 Re-establish N1 NAS Signaling Connection

[0271] When a UE in the "5GMM connected" mode via 3GPP access receives a fallback indication from a lower layer, and the UE has outstanding uplink user data but no outstanding NAS procedures, the UE shall:

[0272] a) Enter the "5GMM idle" mode; and

[0273] b) Initiate a service request procedure (see Subclause 5.6.1).

[0274] When a UE in the "5GMM connected" mode via 3GPP access receives a fallback indication from a lower layer, and the UE has an outstanding registration procedure, service request procedure, or deregistration procedure, the UE shall:

[0275] a) Enter the "5GMM idle" mode; and

[0276] b) Continue with the outstanding procedure (see Subclauses 5.5.1.3, 5.6.1, and 5.5.2.2).

[0277] When a UE in the "5GMM connected" mode via 3GPP access receives a fallback indication from a lower layer, and the UE has an outstanding NAS procedure other than a registration procedure, service request procedure, or deregistration procedure, the UE shall:

[0278] a) Enter the "5GMM idle" mode;

[0279] b) Initiate a service request procedure (see Subclause 5.6.1); and

[0280] c) After successfully completing the service request procedure, continue with any outstanding procedure.

[0281] *****Next change*****

[0282] 5.3.1.4 "5GMM Connected" Mode with RRC Inactivity Indication

[0283] This subclause applies only to the 5GMM mode of the UE via 3GPP access.

[0284] A UE is in the "5GMM connected" mode with RRC inactivity indication when the UE is in the following situations:

[0285] a) The "5GMM Connected" mode via 3GPP access at the NAS layer; and

[0286] b) The RRC_INACTIVE state at the AS layer (see 3GPP TS 38.300

[27] ).

[0287] Unless otherwise specified, the UE behavior in the "5GMM Connected" mode with RRC inactivity indication will follow the UE behavior in the "5GMM Connected" mode via 3GPP access, except for the following cases:

[0288] a) The UE will apply mobility restrictions; and

[0289] b) The UE will perform the PLMN selection procedure,

[0290] as if it were in the "5GMM Idle" mode via 3GPP access.

[0291] After receiving an indication from the lower layer that the UE has transitioned to the RRC_INACTIVE state, the UE will transition from the "5GMM Connected" mode via 3GPP access to the "5GMM Connected" mode with RRC inactivity indication.

[0292] After the following situations:

[0293] - Triggering a procedure that requires sending a NAS message; or

[0294] - Sending an uplink user data packet for a PDU session with suspended user plane resources;

[0295] The UE in the "5GMM Connected" mode with RRC inactivity indication via 3GPP access will request the lower layer to transition to the RRC_CONNECTED state (see 3GPP TS 38.300

[27] ).

[0296] After receiving an indication from the lower layer that the UE has transitioned to the RRC_CONNECTED state, the UE will transition from the "5GMM Connected" mode with RRC inactivity indication to the "5GMM Connected" mode via 3GPP access (see 3GPP TS38.300

[27] ).

[0297] Note: The AMF is able to be aware of the transition of the UE between the "5GMM Connected" mode and the "5GMM Connected" mode with RRC inactivity indication (see 3GPP TS23.502 [9]).

[0298] Once a PLMN that is not equivalent to the registered PLMN is selected, the UE shall trigger a transition from the "5GMM connected" mode with RRC inactivity indication to the "5GMM idle" mode. After entering a new PLMN in the list of equivalent PLMNs, the UE shall not trigger a transition from the "5GMM connected" mode with RRC inactivity indication to the "5GMM idle" mode.

[0299] If the UE requests the lower layer to transition to the RRC_CONNECTED state when initiating a registration procedure, a service request procedure, or a deregistration procedure, then after a fallback indication from the lower layer, the UE shall:

[0300] - Enter the "5GMM idle" mode; and

[0301] - Continue with the pending procedures (see subclauses 5.5.1.3, 5.6.1, and 5.5.2.2).

[0302] If the UE requests the lower layer 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 after a fallback indication from the lower layer, the UE shall:

[0303] - Enter the "5GMM idle" mode;

[0304] - Initiate a service request procedure (see subclause 5.6.1); and

[0305] - After successful completion of the service request procedure, continue with any pending procedures.

[0306] If a UE in the "5GMM connected" mode with RRC inactivity indication receives a fallback indication from the lower layer, and the UE has pending uplink user data but no pending NAS procedures, the UE shall:

[0307] - Enter the "5GMM idle" mode; and

[0308] - Initiate a service request procedure (see subclause 5.6.1).

[0309] After receiving the following from the lower layer, the UE shall transition from the "5GMM connected" mode with RRC inactivity indication to the "5GMM idle" mode via 3GPP access and initiate a registration procedure for mobility and periodic registration update for mobility (i.e., the 5GS registration type IE set to "mobility registration update" in the "Registration Request" message) for NAS signaling connection restoration as specified in subclause 5.5.1.3.2:

[0310] a) Indication that the transition from RRC_INACTIVE state to RRC_CONNECTED state has failed; or

[0311] b) Fallback indication without a recovery request from NAS.

[0312] The UE shall transition from the "5GMM Connected" mode with RRC Inactive indication to the "5GMM Idle" mode via 3GPP access after receiving the following from the lower layers:

[0313] a) Indication of the transition from RRC_INACTIVE state to RRC_IDLE state;

[0314] b) AMF paging indication; or

[0315] c) Indication of cell selection for E-UTRAN or another RAT supported by the UE.

[0316] *****Next change*****

[0317] 5.5.1.3.2 Mobility and Periodic Registration Update Initiation

[0318] The UE in the state "5GMM Registered" shall initiate the registration procedure for mobility and periodic registration update by sending a "Registration Request" message to the AMF,

[0319] a) When the UE detects entry into a tracking area that is not in the list of tracking areas where the UE was previously registered with the AMF;

[0320] b) When the periodic registration update timer T3512 expires;

[0321] c) When requested by a "Configuration Update Command" message;

[0322] d) When the UE in the state 5GMM-REGISTERED.ATTEMPTING-REGISTRATION-UPDATE receives a paging or the UE receives a notification message with an indication of the access type of a PDU session associated with 3GPP access via non-3GPP access;

[0323] e) After an inter-system change from S1 mode to N1 mode;

[0324] f) When the UE receives from the lower layers an indication that the transition from RRC_INACTIVE state to RRC_CONNECTED state has failed (see Subclause 5.3.1.4);

[0325] g) When the UE changes its 5GMM capabilities or S1 UE network capabilities or both;

[0326] h) When the usage settings of the UE change;

[0327] i) When the UE needs to change the slice it is currently registered to;

[0328] j) When the UE changes UE-specific DRX parameters;

[0329] k) When a UE in the state 5GMM-REGISTERED.ATTEMPTING-REGISTRATION-UPDATE receives a request from the upper layer to establish an emergency PDU session or perform an emergency service fallback;

[0330] l) When the UE needs to register for SMS over NAS, indicates a change in the requirements for using SMS over NAS, or deregisters from SMS over NAS;

[0331] m) When, after the local release of a PDU session as specified in Subclauses 6.4.1.5 and 6.4.3.5, the UE needs to indicate the PDU session state to the network;

[0332] n) When a UE in the "5GMM idle" mode changes its radio capabilities with the NG-RAN;

[0333] o) When the UE receives a fallback indication from the lower layer without a recovery request from the NAS (see Subclause 5.3.1.4);

[0334] p) When the UE receives a fallback indication from the lower layer and has a pending registration procedure for mobility and periodic registration update (see Subclauses 5.3.1.2 and 5.3.1.4).

[0335] If item b) is the only reason to initiate a registration procedure for mobility and periodic registration update, the UE shall indicate "Periodic Registration Update" in the 5GS Registration Type IE; otherwise, the UE shall indicate "Mobility Registration Update".

[0336] If the UE indicates "Mobility Registration Update" in the 5GS Registration Type IE and the UE supports S1 mode, the UE shall:

[0337] - Set the S1 mode bit to "Support S1 mode" in the 5GMM capabilities IE of the "Registration Request" message;

[0338] - Include the S1 UE network capabilities IE in the "Registration Request" message; and

[0339] - If the UE supports sending an attach request message that includes a "PDN connection request" message with the request type set to "handover" to transfer the PDU session from N1 mode to S1 mode, then the HO attach bit shall be set in the 5GMM function IE of the "registration request" message to "attach request message that includes a PDN connection request with the request type set to handover to transfer the PDU session from N1 mode to the supported S1 mode".

[0340] 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 (see Annex D) in the payload container IE of the "registration request" message.

[0341] When a UE in the state "5GMM registered" needs to request the use of SMS transmission via NAS or change the current requirements for using SMS transmission via NAS in the UE, the UE shall initiate the registration process 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.

[0342] When initiating the registration process for mobility and periodic registration updates and the requirements for using SMS via NAS have not changed in the UE, the UE shall set the SMS request 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.

[0343] If the UE no longer needs to use SMS via NAS, the UE shall set the SMS request bit of the 5GS registration type IE in the "registration request" message to "does not support SMS via NAS".

[0344] After sending the "registration request" message to the AMF, the UE shall start timer T3510. If timer T3502 is currently running, the UE shall stop timer T3502. If timer T3511 is currently running, the UE shall stop timer T3511.

[0345] If the last accessed registered TAI is available, the UE shall include the last accessed registered TAI in the "registration request" message.

[0346] The UE shall handle the 5GS mobility identity IE in the "registration request" message as described below:

[0347] a) If the UE is operating in single registration mode, performs an inter-system change from S1 mode to N1 mode, and the UE retains 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 retains a valid 5G-GUTI, the UE shall include the 5G-GUTI in the additional GUTI IE in the "Registration Request" message; and

[0348] b) For all other cases, if the UE retains a valid 5G-GUTI, the UE shall indicate the 5G-GUTI in the 5GS mobility identity IE.

[0349] If the UE supports the MICO mode and requests to use the MICO mode, the UE shall include the MICO indication IE in the "Registration Request" message.

[0350] If the UE wants to change the UE-specific DRX parameters, the UE shall include the requested DRX parameter IE in the "Registration Request" message.

[0351] If the UE wants the 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:

[0352] - Request a specific LADN DNN by including the LADN DNN value in the LADN indication IE for each LADN DNN for which the UE requests LADN information; or

[0353] - Indicate a request for LADN information by not including any LADN DNN value in the LADN indication IE.

[0354] If the UE is initiating a registration procedure for mobility and periodic registration update, the UE may include the uplink data status IE to indicate which (if any) PDU sessions have pending user data to be sent. If the UE has one or more active always-on PDU sessions and the user plane resources for these PDU sessions are not established, the UE shall include the uplink data status IE and indicate that for those PDU sessions, the UE has pending user data to be sent. If the UE is located outside the LADN service area, the UE shall not include the PDU session for LADN in the uplink data status IE.

[0355] If the UE has one or more active PDU sessions that are not accepted by the network as always-on PDU sessions and there is no uplink user data pending for transmission for those PDU sessions, the UE shall not include those PDU sessions in the uplink data status IE in the "Registration Request" message.

[0356] When initiating the registration procedure for mobility and periodic registration update in the "5GMM Idle" mode, the UE may include the PDU session status IE in the "Registration Request" message, where the PDU session status IE indicates which PDU sessions associated with the access type for which the "Registration Request" message has been sent are active in the UE.

[0357] If the UE receives a paging message with an access type indicating non-3GPP access, the UE shall include the allowed PDU session status IE in the "Registration Request" message to indicate the PDU sessions for which the UE allows the reconstruction of user plane resources via 3GPP access.

[0358] If a UE operating in single registration mode performs an inter-system change from S1 mode to N1 mode, the UE:

[0359] a) shall include in the "Registration Request" message a UE status IE with the EMM registration status set to "UE is in EMM-Registered state";

[0360] Note 1: Including the UE status IE with this setting corresponds to the indication that the UE is "Moving from EPC" as specified in Subclauses 4.11.1.3.3 and 4.11.2.3 of 3GPP TS 23.502 [9].

[0361] b) may include in the "Registration Request" message a PDU session status IE to indicate the status of the PDU sessions mapped during the inter-system change from S1 mode to N1 mode from the PDN connection, for which the EPS indicates support for interworking with 5GS (if any) (see Subclause 6.1.4.1); and

[0362] c) shall include in the EPS NAS message container IE in the "Registration Request" message the "Tracking Area Update Request" message as specified in 3GPP TS 24.301

[15] .

[0363] 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 an active EPS bearer context, the UE shall include in the requested NSSAI IE in the "Registration Request" message:

[0364] a) S-NSSAI, where the S-NSSAI:

[0365] 1) is associated with an established PDN connection; and

[0366] 2) is applicable in the serving PLMN; and

[0367] b) If the mapping information is available at the UE, map these S-NSSAIs to the S-NSSAIs of the configured NSSAI of the HPLMN.

[0368] The UE shall include the requested NSSAI, which contains the S-NSSAI corresponding to the slice to which the UE wants to register, and shall include in the "Registration Request" message the mapping of the requested NSSAI, which is the mapping of each S-NSSAI of the requested NSSAI to the S-NSSAI of the configured NSSAI of the HPLMN (if available). If the UE has the allowed NSSAI or the configured NSSAI of the current PLMN, then:

[0369] a) If the UE does not have the allowed NSSAI of the current PLMN, the requested NSSAI shall be the configured NSSAI of the current PLMN, or a subset of the NSSAI as described below;

[0370] b) If the UE has the allowed NSSAI of the current PLMN, the requested NSSAI shall be the allowed NSSAI of the current PLMN, or a subset of the NSSAI as described below; or

[0371] c) The allowed NSSAI of the current PLMN, or a subset of the NSSAI as described below, plus one or more S-NSSAIs from the configured NSSAI, for which there is no corresponding S-NSSAI in the allowed NSSAI, and 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.

[0372] If the UE has neither the allowed NSSAI of the current PLMN nor the configured NSSAI of the current PLMN, but has a configured NSSAI not associated with the 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 does not have the allowed NSSAI of the current PLMN, does not have the configured NSSAI of the current PLMN, and does not have a configured NSSAI not associated with the PLMN, the UE shall not include the requested NSSAI in the "Registration Request" message.

[0373] 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, the subset of the configured NSSAI provided in the requested NSSAI consists of one or more S-NSSAIs from the configured NSSAI applicable to this PLMN.

[0374] If a rejected S-NSSAI is added through a configuration update procedure and 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, the subset of the permitted NSSAI provided in the requested NSSAI consists of one or more S-NSSAIs from the permitted NSSAI of this PLMN.

[0375] Note 2: How the UE selects the subset of the configured NSSAI or permitted NSSAI to be provided in the requested NSSAI is an implementation matter.

[0376] Note 3: The number of S-NSSAIs included in the requested NSSAI shall not exceed eight.

[0377] If the UE performs the following operations, the UE shall set the "pending subsequent request" indication to 1:

[0378] a) Initiates a mobility and periodic registration update procedure after requesting the upper layer to establish an emergency PDU session;

[0379] b) Initiates a mobility and periodic registration update procedure after receiving a request from the upper layer to send NAS signaling associated with emergency service fallback; or

[0380] c) Needs to extend an established NAS signaling connection after completing the registration procedure for mobility and periodic registration update (e.g., due to uplink signaling pending but no user data pending).

[0381] For case n), the UE shall set the NG-RAN-RCU bit of the 5GS registration type IE in the "registration request" message to "NG-RAN radio capability update required".

[0382] For case p), the UE shall include the UL data status IE in the "registration request" message. The UL data status IE indicates the PDU sessions (if any) in which the user plane resources were active before receiving the fallback indication from the lower layer, and the PDU sessions (if any) in which the user plane resources were inactive before receiving the fallback indication from the lower layer and the UE has pending user data to be sent via 3GPP access.

[0383] *****Next change*****

[0384] 5.6.1.1 General

[0385] 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 either the "5GMM Idle" mode or the "5GMM Connected" mode. This procedure is used in the following cases:

[0386] - The network has outstanding downlink signaling on 3GPP access and the UE is in the "5GMM Idle" mode via 3GPP access;

[0387] - The network has outstanding downlink signaling on non-3GPP access, the UE is in the "5GMM Idle" mode via non-3GPP access and is in the "5GMM Idle" or "5GMM Connected" mode via 3GPP access;

[0388] - The UE has outstanding uplink signaling on 3GPP access and the UE is in the "5GMM Idle" mode via 3GPP access;

[0389] - The network has outstanding downlink user data on 3GPP access and the UE is in the "5GMM Idle" mode via 3GPP access;

[0390] - The network has outstanding downlink user data on non-3GPP access, the UE is in the "5GMM Idle" mode via non-3GPP access and is in the "5GMM Idle" or "5GMM Connected" mode via 3GPP access;

[0391] - The UE has outstanding user data on 3GPP access and the UE is in the "5GMM Idle" or "5GMM Connected" mode via 3GPP access;

[0392] - The UE has outstanding user data on non-3GPP access and the UE is in the "5GMM Connected" mode via non-3GPP access;

[0393] - A UE in the "5GMM Idle" mode via non-3GPP access receives an indication from the lower layers of non-3GPP access that an access stratum connection has been established between the UE and the network; or

[0394] - A UE in the "5GMM Idle" or "5GMM Connected" mode accessing via 3GPP receives a request for emergency service fallback from the upper layer and performs the emergency service fallback as specified in Subclause 4.13.4.2 of 3GPP TS 23.502 [9].

[0395] When the UE is outside the LADN service area, this procedure shall not be used to initiate signaling related to user data transfer or PDU session management, but only to perform the UE-requested PDU session release procedure related to the PDU session with LADN.

[0396] The service request procedure is initiated by the UE. However, the service request procedure can be triggered by the network by means of:

[0397] - The paging procedure for the transfer of downlink signaling or user data pending on 3GPP access to a UE in the "5GMM Idle" mode accessing via 3GPP (see Subclause 5.6.2);

[0398] - The paging procedure for the transfer of downlink signaling or user data pending on non-3GPP access to a UE in the "5GMM Idle" mode accessing via 3GPP and in the "5GMM Idle" mode accessing via non-3GPP (see Subclause 5.6.2);

[0399] - The notification procedure for the transfer of downlink signaling or user data pending on non-3GPP access to a UE in the "5GMM Connected" mode accessing via 3GPP and in the "5GMM Idle" mode accessing via non-3GPP (see Subclause 5.6.3);

[0400] - The notification procedure for the transfer of downlink signaling or user data pending on 3GPP access to a UE in the "5GMM Idle" mode accessing via 3GPP and in the "5GMM Connected" mode accessing via non-3GPP (see Subclause 5.6.3).

[0401] Note: If the UE is in the "5GMM Idle" mode accessing via 3GPP and in the "5GMM Connected" mode accessing via non-3GPP, and there is a need to transfer downlink signaling or user data pending on 3GPP access, the AMF can trigger the notification procedure or the paging procedure based on the implementation.

[0402] The UE shall invoke the service request procedure in the following cases:

[0403] a) A UE in the "5GMM Idle" mode accessing via 3GPP receives a paging request from the network;

[0404] b) A UE in the "5GMM connected" mode via 3GPP access receives a notification from the network with an indication of the access type indicating non-3GPP access;

[0405] c) A UE in the "5GMM idle" mode via 3GPP access has a pending uplink signaling;

[0406] d) A UE in the "5GMM idle" mode via 3GPP access has a pending uplink user data;

[0407] e) A UE in the "5GMM connected" mode has a pending user data due to the lack of user plane resources established for the PDU session for user data transmission;

[0408] f) A UE in the "5GMM idle" mode via non-3GPP access receives an indication from the lower layer of non-3GPP access that an access layer connection is established between the UE and the network;

[0409] g) A UE in the "5GMM idle" mode via 3GPP access receives a notification from the network with an access type indicating 3GPP access when the UE is in the "5GMM connected" mode via non-3GPP access;

[0410] h) A UE in the "5GMM idle" or "5GMM connected" mode via 3GPP access receives a request for emergency service fallback from the upper layer and performs the emergency service fallback as specified in subclause 4.13.4.2 of 3GPP TS 23.502 [9].

[0411] i) A UE in the "5GMM connected" mode via 3GPP access or in the "5GMM connected" mode with an RRC inactivity indication receives a fallback indication from the lower layer (see subclauses 5.3.1.2 and 5.3.1.4), and the UE has pending uplink user data and no pending NAS procedures;

[0412] j) A UE in the "5GMM connected" mode via 3GPP access or in the "5GMM connected" mode with an RRC inactivity indication receives a fallback indication from the lower layer (see subclauses 5.3.1.2 and 5.3.1.4), and the UE has a pending service request procedure invoked for reasons other than case h) in this list;

[0413] k) A UE in the "5GMM Connected" mode via 3GPP access or in the "5GMM Connected" mode with RRC Inactivity Indication receives a fallback indication from a lower layer (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

[0414] l) A UE in the "5GMM Connected" mode via 3GPP access or in the "5GMM Connected" mode with RRC Inactivity Indication receives a fallback indication from a lower layer (see Subclause 5.3.1.4), and the UE has a pending NAS procedure other than a registration, service request, or deregistration procedure.

[0415] If one of the above criteria for invoking a service request procedure is met, the UE shall initiate a service request procedure only when the following conditions are satisfied:

[0416] - Its 5GS update status is "5U1 Updated", and the TAI of the current serving cell is included in the TAI list; and

[0417] - There is no ongoing 5GMM-specific procedure.

[0418] When the UE is in the state 5GMM-SERVICE-REQUEST-INITIATED, the UE shall not invoke a service request procedure.

[0419] The service request attempt counter is used to limit the number of service request attempts and there is no response from the network. The service request attempt counter shall be incremented as specified in Subclause 5.6.1.7.

[0420] The service request attempt counter shall be reset in the following cases:

[0421] - The registration procedure is successfully completed;

[0422] - The service request procedure is successfully completed; or

[0423] - The service request procedure is rejected as specified in Subclause 5.6.1.5.

[0424] *****Next Change*****

[0425] 5.6.1.2 Service Request Procedure Initiation

[0426] The UE initiates a service request procedure by sending a "Service Request" message to the AMF and starts timer T3517.

[0427] For cases a), b) and g) in sub-clause 5.6.1.1, the service type IE in the "Service Request" message shall be set to'mobile terminated service'.

[0428] For cases c), d), e), f), i) and l) in sub-clause 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'.

[0429] For cases h) and k) in sub-clause 5.6.1.1, the UE shall send a "Service Request" message with the service type set to 'emergency service fallback'.

[0430] For case a) in sub-clause 5.6.1.1:

[0431] 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 an S-NSSAI, and these PDU sessions are included in the allowed NSSAI for 3GPP access, the UE shall indicate in the allowed PDU session status IE the PDU sessions for which the UE allows the reconstruction of user plane resources via 3GPP access. Otherwise, the UE shall not indicate any PDU sessions in the allowed PDU session status IE.

[0432] 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 sessions for which the UE has pending user data to send; or

[0433] c) Otherwise, the uplink data status IE shall not be included in the "Service Request" message.

[0434] For case b) in sub-clause 5.6.1.1:

[0435] a) The allowed PDU session status IE shall be included in the "Service Request" message. If the UE has PDU sessions associated with an S-NSSAI, and these PDU sessions are included in the allowed NSSAI for 3GPP access, the UE shall indicate in the allowed PDU session status IE the PDU sessions for which the UE allows the reconstruction of user plane resources via 3GPP access. Otherwise, the UE shall not indicate any PDU sessions in the allowed PDU session status IE.

[0436] 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 sessions for which the UE has pending user data to send;

[0437] c) Otherwise, the uplink data status IE shall not be included in the "Service Request" message.

[0438] For case c) in sub-clause 5.6.1.1, unless the UE has one or more active always-on PDU sessions, the uplink data status IE shall not be included in the "Service Request" message. If the "Service Request" message is triggered by a request for emergency services from the upper layer 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'.

[0439] For cases d) and e) in sub-clause 5.6.1.1, 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. 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'.

[0440] For case f) in sub-clause 5.6.1.1:

[0441] 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 sessions 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';

[0442] 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'.

[0443] For case g) in sub-clause 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.

[0444] For case i) in sub-clause 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 receiving the fallback indication. If the UE is not a UE configured for high-priority access in the selected PLMN and:

[0445] 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

[0446] 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'.

[0447] For case j) in Subclause 5.6.1.1, the UE shall:

[0448] a) Include the uplink data status IE in the "Service Request" message to indicate:

[0449] 1) The PDU sessions (if any) for which the user plane resources were active before receiving the fallback indication; and

[0450] 2) The PDU sessions (if any) for which the user plane resources were inactive before receiving the fallback indication and for which the UE has pending user data to send via 3GPP access;

[0451] b) Set the service type IE in the "Service Request" message as follows:

[0452] 1) If the UE 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 'MT Service'; or

[0453] 2) If the UE invoked a pending service request procedure due to case e) in Subclause 5.6.1.1, and:

[0454] 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

[0455] ii) If the UE is not a UE configured for high-priority access in the selected PLMN, and:

[0456] 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

[0457] 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

[0458] c) If the UE has invoked a pending service request procedure due to case b) in subclause 5.6.1.1, include the allowed PDU session status IE in the "Service Request" message. If the UE has one or more PDU sessions associated with an S-NSSAI included in the allowed NSSAI for non-3GPP access that are related to the S-NSSAI for 3GPP access, and the UE allows the 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.

[0459] For case l) in subclause 5.6.1.1:

[0460] a) The UE shall handle including the uplink data status IE in the "Service Request" message as follows:

[0461] 1) If a UE in the "5GMM Connected" mode over 3GPP access invokes a service request procedure, the UE shall include the uplink 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 a fallback indication; or

[0462] 2) If a UE in the "5GMM Connected" mode with an RRC inactivity indication invokes a service request procedure, the UE shall 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

[0463] b) A UE not configured for high-priority access in the selected PLMN shall set the service type IE in the "Service Request" message as follows:

[0464] 1) If the pending message is a "UL NAS Transport" 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

[0465] 2) If the pending message is not a "UL NAS Transport" 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'.

[0466] The UE shall include a valid 5G-S-TMSI in the 5G-S-TMSI IE of the "Service Request" message.

[0467] If the UE has one or more active always-on PDU sessions and the user plane resources for these PDU sessions are not established, 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.

[0468] If the UE has one or more active PDU sessions that are not accepted by the network as always-on PDU sessions and there is no uplink user data pending for those PDU sessions, the UE shall not include those PDU sessions in the uplink data status IE in the "Service Request" message.

[0469] 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 for which the "Service Request" message has been sent. If the PDU session status information element is included in the "Service Request" message, the AMF shall release locally (without peer signaling between the UE and the network) all those PDU sessions that are active on the AMF side associated with the access type for which the "Service Request" message has been sent but are indicated by the UE as being inactive, and shall request the SMF to release locally all these PDU sessions.

[0470] *****Next change*****

[0471] 5.6.1.4 Network Accepted Service Request Procedure

[0472] For cases other than h) or k) in Subclause 5.6.1.1, the UE shall consider the reception of the "Service Accept" message as the successful completion of the procedure. The UE shall reset the service request attempt counter, stop timer T3517, and enter the state "5GMM Registered".

[0473] For cases h) and k) in Subclause 5.6.1.1, the UE shall consider the indication from the lower layer when the UE has changed to S1 mode or is connected to E-UTRA of the 5GCN (see 3GPP TS23.502 [9]) as the successful completion of the procedure and stop timer T3517.

[0474] If the AMF needs to initiate PDU session status synchronization or the PDU session status IE is included in the "Service Request" message, the AMF shall include the PDU session status IE in the "Service Accept" message to indicate which PDU sessions associated with the access type for which the "Service Accept" message has been sent are active in the AMF. If the PDU session status information element is included in the "Service Accept" message, the UE shall release locally (without peer signaling between the network and the UE) all those PDU sessions that are active on the UE side associated with the access type for which the "Service Accept" message has been sent but are indicated by the AMF as being inactive.

[0475] If the uplink data status IE is included in the "Service Request" message, the AMF shall:

[0476] a) Indicate to the SMF to reconstruct the user plane resources for the corresponding PDU session;

[0477] b) Include the PDU session reactivation result IE in the "Service Accept" message to indicate the user plane resource reactivation result of the PDU session that the UE requested to reconstruct;

[0478] c) If the corresponding PDU session is a PDU session for LADN, determine the presence of the UE in the LADN service area and forward the presence of the UE in the LADN service area to the SMF; and

[0479] d) If the corresponding PDU session is a PDU session for LADN and the SMF indicates to the AMF that the UE is located outside the LADN service area, include cause #43 "LADN not available" to indicate in the PDU session reactivation result error cause IE of the "Service Accept" message that the user plane resources of the PDU session have not been established.

[0480] If the allowed PDU session status IE is included in the "Service Request" message, the AMF shall:

[0481] a) Indicate to the SMF to reconstruct the user plane resources for the corresponding PDU session allowed to be reconstructed via 3GPP access, and indicate pending downlink data in the case where there is at least one PDU session allowed to be reconstructed via 3GPP access indicated in the allowed PDU session status IE;

[0482] b) Notify the SMF that pending downlink data has been indicated and that reactivation of the user plane resources for the corresponding PDU session cannot be performed if reconstruction via 3GPP access is not allowed; and

[0483] c) Include the PDU session reactivation result IE in the "Service Accept" message to indicate the successful reconstruction of the user plane resources (if any) for the corresponding PDU session.

[0484] If the AMF has included the PDU session reactivation result IE in the "Service Accept" message and there is one or more PDU sessions for which the user plane resources cannot be reconstructed, the AMF may include the PDU session reactivation result error cause IE to indicate the reason why the user plane resources cannot be reconstructed.

[0485] If, as described in Subclause 4.2.3.2 of 3GPP TS 23.502 [9], the user plane resources cannot be established for a PDU session due to unavailability of resources in the UPF, the AMF shall include in the "Service Accept" message the PDU session reactivation result IE indicating that the user plane resources for the corresponding PDU session cannot be reconstructed, and shall include the PDU session reactivation result error cause IE with the 5GMM cause set to #92 "Insufficient user plane resources for the PDU session".

[0486] Note: When to re - send the request for user plane reconstruction for the associated PDU session after receiving the PDU session reactivation result error cause IE with the 5GMM cause set to #92 "Insufficient user plane resources for the PDU session" depends on the UE implementation.

[0487] If the "Service Request" message is used for emergency service fallback, the AMF triggers the emergency service fallback procedure as specified in Subclause 4.13.4.2 of 3GPP TS 23.502 [9].

[0488] Figure 15 A schematic diagram of a figure showing a method for performing the registration request procedure that can be incorporated into 3GPP TS 24.501 (e.g., in Section 5.5.1.3.2).

[0489] Figure 16 A schematic diagram of a figure showing a method for performing the service request procedure that can be incorporated into 3GPP TS 24.501 (e.g., in Section 5.6.1.1).

[0490] Note that although the example implementation is described above, various changes and modifications can be made to the disclosed solution without departing from the scope of the present invention.

[0491] Embodiments may thus vary within the scope of the appended claims. Generally, some embodiments may be implemented in hardware or dedicated circuitry, 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 executable 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, flowcharts, or using some other graphical representation, it should be understood that, as a non-limiting example, the blocks, devices, systems, techniques, or methods described herein may be implemented in hardware, software, firmware, dedicated circuitry or logic, general hardware or a controller or other computing device, or some combination thereof.

[0492] 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. In this regard, it should be noted, for example, that any process, such as Figures 6 to 13 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 a physical medium such as a memory chip or a memory block implemented within a processor, a magnetic medium such as a hard disk or a floppy disk, and an optical medium such as a DVD and its data variants, a CD.

[0493] 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, as a non-limiting example, may include one or more of the following: general-purpose computers, special-purpose computers, microprocessors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), gate-level circuits, and processors based on a multi-core processor architecture.

[0494] Alternatively or additionally, some embodiments may be implemented using circuitry. The circuitry may be configured to perform one or more of the previously described functions and / or method steps. The circuitry may be provided in a base station and / or in a communication device.

[0495] As used in this application, the term "circuitry" may refer to one or more or all of the following:

[0496] (a) A pure hardware circuit implementation (such as an implementation only in analog and / or digital circuitry);

[0497] (b) A combination of hardware circuitry and software, for example:

[0498] (i) A combination of analog and / or digital hardware circuits and software / firmware, and

[0499] (ii) Any part of a hardware processor having software (including a digital signal processor), software, and memory, which work together to cause a device, such as a communication device or a base station, to perform the various functions described previously; and

[0500] (c) Hardware circuits and / or processors, such as a microprocessor or a part of a microprocessor, which require software (e.g., firmware) to operate, but the software may be absent when not required to operate.

[0501] This definition of a circuit applies to all uses of this term in this application, including in any claims. As another example, as used in this application, the term circuit also covers an implementation of only a hardware circuit or a processor (or processors) or a part of a hardware circuit or a processor and its (or their) accompanying software and / or firmware. The term circuit also encompasses, for example, an integrated device.

[0502] The foregoing description has provided a comprehensive and informative description of some embodiments by way of exemplary and non-limiting examples. However, various modifications and changes 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 user equipment, the user equipment comprising: At least one processor; And At least one memory, the at least one memory including computer program code which, when executed by the at least one processor, causes the user equipment to at least: Receive a fallback indication; Invoke a service request procedure; and Set a service type information element in a service request message.

2. The user equipment according to claim 1, wherein the computer program code, when executed by the at least one processor, causes the user equipment to at least: Invoke the service request procedure based on the user equipment having one of the following: a pending service request procedure due to a reason different from a predetermined reason, a pending service request procedure due to the predetermined reason, or a pending non-access stratum procedure other than a service request procedure.

3. The user equipment according to claim 2, wherein the pending service request procedure due to a reason other than the predetermined reason is a pending service request procedure that the user equipment has invoked due to a reason different from emergency service fallback.

4. The user equipment according to claim 2, wherein the pending service request procedure due to the predetermined reason is a pending service request procedure that the user equipment has invoked due to emergency service fallback.

5. The user equipment according to claim 2, wherein the pending non-access stratum procedure other than the service request procedure is a pending non-access stratum procedure other than a registration procedure, a service request procedure, or a deregistration procedure.

6. The user equipment according to any one of claims 1 to 5, wherein the user equipment is in a connected mode.

7. The user equipment according to any one of claims 1 to 5, wherein the user equipment is in a connected inactive mode.

8. The user equipment according to any one of claims 2 to 7, wherein the computer program code, when executed by the at least one processor, causes the user equipment to at least: Set the service type information element in the service request message according to the user equipment having one of the following: a pending service request procedure due to a reason different from the predetermined reason, a pending service request procedure due to the predetermined reason, or a pending non-access stratum procedure other than a service request procedure.

9. The user equipment according to claim 8, wherein the computer program code, when executed by the at least one processor, causes the user equipment to at least: When the user equipment has a pending service request procedure 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".

10. The user equipment according to claim 8, wherein the computer program code, when executed by the at least one processor, causes the user equipment to at least: When the user equipment has the pending service request procedure due to the predetermined reason, set the service type information element in the service request message to "Emergency Service Fallback".

11. The user equipment according to claim 8, wherein the computer program code, when executed by the at least one processor, causes the user equipment to at least: When the user equipment has the pending non-access stratum procedure other than the service request procedure, set the service type information element in the service request message to "High Priority Access", "Emergency Service" or "Signaling".

12. The user equipment according to any one of claims 2 to 11, wherein the computer program code, when executed by the at least one processor, causes the user equipment to at least: Set the uplink data status information element in the service request message.

13. The user equipment according to claim 12, wherein the computer program code, when executed by the at least one processor, causes the user equipment to at least: When the user equipment has the pending service request procedure due to the reason different from the predetermined reason, set the uplink data status information element in the service request message to indicate: the packet data unit session in which the user plane resources are active before invoking the service request procedure, and / or the packet data unit session in which the user plane resources are inactive before receiving the fallback indication and the user equipment has pending user data to be sent via the cellular network.

14. The user equipment according to claim 12, wherein the computer program code, when executed by the at least one processor, causes the user equipment to at least: When the user equipment is in the connected mode and has the pending non-access stratum procedure other than the service request procedure, set the uplink data status information element in the service request message to indicate the packet data unit session in which the user plane resources are active before invoking the service request procedure.

15. The user equipment according to claim 12, wherein the computer program code, when executed by the at least one processor, causes the user equipment to at least: When the user equipment is in the connected inactive mode and has the pending non-access stratum procedure other than the service request procedure, set the uplink data status information element in the service request message to indicate the always-on packet data unit session.

16. The user equipment according to any one of claims 1 to 15, wherein the user equipment is configured to at least one of the following: Receive the fallback indication at the non-access stratum; Invoke the service request procedure at the non-access stratum; Set the service type information element in the service request message at the non-access stratum; Set the uplink data status information element in the service request message at the non-access stratum.

17. The user equipment according to any one of claims 1 to 16, wherein the computer program code, when executed by the at least one processor, causes the user equipment to at least: After sending the service request message to the network: Start a service request retransmission timer; and Increment a service request attempt counter.

18. The user equipment according to claim 17, wherein the computer program code, when executed by the at least one processor, causes the user equipment to at least: After receiving a service request acceptance message from the network indicating that the service request process has been completed: Stop the service request retransmission timer; and Reset the service request attempt counter.

19. The user equipment according to claim 17, wherein the computer program code, when executed by the at least one processor, causes the user equipment to at least: After receiving an indication of a mode or connection change indicating that the service request process has been completed: Stop the service request retransmission timer; and Reset the service request attempt counter.

20. A method, the method comprising: Receiving a fallback indication; Invoking a service request process; And Setting a service type information element in a service request message.

21. A computer program, the computer program comprising computer-executable instructions that, when run on one or more processors of a user equipment, cause the user equipment to perform the steps of the method according to claim 20.

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