Method and apparatus for providing emergency services in a network

Abstract

A method for a UE in a network to request emergency services is disclosed. The method includes: when emergency services are needed, if the UE is using CP CIoT optimization, sending a NAS message including an indication of requesting emergency services. The NAS message may be a CPSR message, and the indication may be a predetermined value (e.g., indicating "emergency services") in a predetermined field of the message (e.g., a control plane service type field). Alternatively, the NAS message may be a service request message, the indication may be a predetermined value (e.g., indicating "emergency services" or "emergency services fallback") in a predetermined field of the message (e.g., a service type field), and the service request message may be sent preferentially before sending a message (e.g., a CPSR message) for sending data (e.g., not related to emergency services).

Description

Technical Field

[0001] Certain examples of the present disclosure provide methods and apparatus for providing emergency services to user equipment (UE) in a network. For example, certain examples of the present disclosure provide methods and apparatus for enabling emergency services for UEs optimized for cellular Internet of Things (CIoT) using control plane (CP) in third generation (3GPP) fifth generation (5G). Background Art

[0002] In order to meet the increasing demand for wireless data services since the deployment of the fourth generation (4G) communication system, efforts have been made to develop improved 5G or quasi-5G communication systems. Therefore, 5G or quasi-5G communication systems are also called "super 4G networks" or "post-LTE systems."

[0003] 5G communication systems are considered to be implemented in higher frequency (mmWave) bands (e.g., 60 GHz bands) in order to achieve higher data rates. In order to reduce the propagation loss of radio waves and increase the transmission distance, beamforming, massive multiple-input multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive antenna technologies are discussed in 5G communication systems.

[0004] In addition, in the 5G communication system, system network improvements are being developed based on advanced small cells, cloud radio access networks (RAN), ultra-dense networks, device-to-device (D2D) communications, wireless backhaul, mobile networks, collaborative communications, coordinated multi-point (CoMP), receiving-end interference cancellation, etc.

[0005] In 5G systems, hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC) have been developed as advanced coded modulation (ACM), and filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) as advanced access technologies.

[0006] The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with respect to the present invention. Summary of the invention

[0007] [Technical issues]

[0008] Certain embodiments herein will provide methods and apparatus for providing emergency services in a network.

[0009] Furthermore, certain examples of the present disclosure provide methods and apparatus for enabling emergency services for UEs optimized using CP CIoT in 3GPP 5G.

[0010] [Solution]

[0011] The purpose of certain examples of the present disclosure is to at least partially address, solve and / or alleviate at least one of the problems and / or disadvantages associated with the related art, such as at least one of the problems and / or disadvantages described herein. The purpose of certain examples of the present disclosure is to provide at least one advantage over the related art, such as at least one advantage described herein.

[0012] The invention is defined in the independent claim. Advantageous features are defined in the dependent claims.

[0013] Other aspects, advantages, and salient features will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses examples of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] For a better understanding of the invention, and to show how embodiments of the invention may be implemented, reference is now made, by way of example, to the accompanying drawings, in which:

[0015] Figure 1 An exemplary method for providing emergency services in a network that may be used in examples of the present disclosure is shown.

[0016] Figure 2 Another exemplary method for providing emergency services in a network that may be used in examples of the present disclosure is shown.

[0017] Figure 3 Another exemplary method for providing emergency services in a network that may be used in examples of the present disclosure is shown.

[0018] Figure 4 A block diagram of exemplary network entities that may be used in certain examples of the present disclosure is shown. DETAILED DESCRIPTION

[0019] The examples of the present disclosure are described below with reference to the accompanying drawings to help fully understand the present invention as defined by the claims. The description includes various specific details to help understanding, but these are considered to be exemplary only. Therefore, those of ordinary skill in the art will recognize that various changes and modifications may be made to the embodiments described herein without departing from the scope of the present invention.

[0020] The same or similar components may be denoted by the same or similar reference numerals even though they are shown in different drawings.

[0021] For the sake of clarity and conciseness, detailed descriptions of techniques, structures, configurations, functions, or processes known in the art may be omitted to avoid obscuring the subject matter of the present invention.

[0022] The terms and words used herein are not limited to the bibliographical or standard meanings, but, are merely used to enable a clear and consistent understanding of the invention.

[0023] Throughout the specification and claims herein, the words “comprise,” “include,” and “contain,” and variations of these words, such as “comprising” and “comprises,” mean “including but not limited to,” and are not intended to (and do not) exclude other features, elements, components, integers, steps, processes, operations, functions, features, characteristics, and / or groups thereof.

[0024] Throughout the specification and claims herein, singular forms such as "a," "an," and "the" encompass plural forms unless the context requires otherwise. For example, reference to "an object" includes reference to one or more of such objects.

[0025] Throughout the specification and claims herein, language of the general form "X for Y" (where Y is some action, process, operation, function, action or step, and X is some means for performing the action, process, operation, function, action or step) encompasses a means X that is specifically, but not necessarily exclusively, adapted, configured or arranged to perform Y.

[0026] Features, elements, components, integers, steps, processes, operations, functions, features, characteristics and / or groups thereof described or disclosed in conjunction with a particular aspect, embodiment, example or claim of the present invention should be understood to be applicable to any other aspect, embodiment, example or claim described herein unless incompatible therewith.

[0027] Abbreviations, Acronyms and Definitions

[0028] In this disclosure, the following abbreviations, acronyms, and definitions are used.

[0029] 3GPP: 3rd Generation Partnership Project

[0030] 2G: 2nd Generation

[0031] 3G: 3rd Generation

[0032] 5G: 5th Generation

[0033] 5GC: 5G Core

[0034] 5GMM: 5G Mobility Management

[0035] 5GS: 5G System

[0036] AMF: Access and Mobility Management Function

[0037] CIoT: Cellular IoT

[0038] CP: Control plane

[0039] CPSR: Control Plane Service Request

[0040] CS: Circuit Switching

[0041] CSFB: Circuit Switch Fallback

[0042] EDGE: Enhanced Data Rates for GSM Evolution

[0043] EPS: Evolved Packet System

[0044] ESM: EPS Session Management

[0045] E-UTRA: Evolved Universal Terrestrial Radio Access

[0046] GERAN GSM EDGE: Radio Access Network

[0047] GSM: Global System for Mobile Communications

[0048] ID: ID / Identifier

[0049] IE: Information Elements

[0050] IoT: Internet of Things

[0051] MME: Mobility Management Entity

[0052] N1: Interface between UE and AMF

[0053] N1 mode: A mode that allows UEs to access the 5G core network via the 5G access network

[0054] N3: Interface between UPF and NG-RAN

[0055] N26: Interface between AMF and MME

[0056] NAS: Non-Access Stratum

[0057] NB: Narrow Band

[0058] NG: Next Generation

[0059] PDN: Packet Data Network

[0060] PDU: Protocol Data Unit

[0061] RAN: Radio Access Network

[0062] RAT: Radio Access Technology

[0063] RRC: Radio Resource Control

[0064] S1 mode: A mode in which the UE operates according to the functional division of the S1 interface used between the radio access network and the core network

[0065] SMS: Short Message Service

[0066] SR: Service Request

[0067] TAU: Tracking Area Updates

[0068] TS: Technical Specification

[0069] UE: User Equipment

[0070] UL: Uplink

[0071] UMTS: Universal Mobile Telecommunications System

[0072] UP: User plane

[0073] UPF: User Plane Function

[0074] UTRAN: UMTS Terrestrial Radio Access Network

[0075] WB: Broadband

[0076] In this article, the following literature is referenced:

[0077] [1]3GPP TS 24.501 V16.3.0

[0078] [2]3GPP TS 24.301 V16.3.0

[0079] Overview of CIoT Optimization

[0080] There are two main types of CIoT optimization, known as: UP CIoT optimization and CP CIoT optimization. Both types of CIoT optimization are applicable to EPS and 5G.

[0081] UP CIoT optimization refers to optimization related to the use of user plane resources. CP CIoT optimization refers to optimization related to the efficient transmission of data on the control plane. Note that "data" can also refer to SMS and location service messages.

[0082] NAS specifications TS 24.501[1] (for N1 mode) and TS 24.301[2] (for S1 mode) provide a description of these optimizations, and in particular, some sections specify UE and network behavior when using CP CIoT optimizations. For example, sections 5.6.1.2.2 and 5.6.1.4.2 are particularly targeted at the use of CP CIoT optimizations.

[0083] One major aspect of CP CIoT optimization is that the UE can send data in idle mode using the CPSR message defined in [1] and [2]. Although the content of the CPSR message for 5G defined in [1] is not exactly the same as the content of the CPSR message for EPS defined in [2], there are some common aspects between these messages. For example, there is a control plane service type field in the CPSR defined in [1], which defines a control plane service type value that can indicate "mobile originating request" (the 3-bit field will have a value of '000') or "mobile terminating request" (the 3-bit field will have a value of '001'). Similarly, for the control plane service type value of the control plane service type field in the CPRS message in [2], [2] uses the same value.

[0084] As will be explained below, typically the UE uses one of these optimizations at a time, although it is possible to use both optimizations simultaneously. When the UE uses CP CIoT optimization, the UE's PDU session (or PDN connection in S1 mode) will be used to transmit data on the control plane, i.e., on NAS signaling messages. However, if the PDU Session Establishment Accept message includes a Control Plane Only Indication IE (see [1]), the PDU session used for CP CIoT optimization can be a control plane only session, or the session can be used for CP CIoT optimization and can be switched to a user plane session. Note that the latter is not a permanent switch to a user plane session, but the UE can request to establish user plane resources and use these resources to transmit data on the user plane. The UE can request to switch the session to the user plane based on, for example, the amount of data that needs to be sent or based on other unspecified conditions. However, it is important to note that the PDU session used for CP CIoT optimization can be a control plane only session, or the UE can be allowed to request to establish user plane resources to transmit data on the user plane while still considering that the session is used for CP CIoT optimization.

[0085] When a PDU session is switched to the user plane (i.e., when user plane resources are established for such a PDU session), if the UE also supports UP CIoT optimization, the UE may apply UP CIoT optimization to the session for which the user plane has been established. Note that after releasing the user plane resources, the UE continues to use the session as a session for CP CIoT optimization unless the UE requests to establish user plane resources again. Note that although user plane resources may be established for a PDU session for CP CIoT optimization, the UE maintains the use of CPSR messages when the UE needs to initiate a service request procedure for the corresponding PDU session.

[0086] However, if a UE supporting WB-EUTRA is capable of emergency services, emergency services are not supported on NB-IoT but are supported on E-UTRA (ie, WB-EUTRA).

[0087] Contents of service request and control plane service request messages

[0088] The service request message defined in [1] has a mandatory field called the service type field, which indicates the reason for sending the service request message by the UE based on a set value. For example, when the UE needs to request emergency services, as defined in section 9.11.3.50 of [1], the service type field will be set to "emergency services".

[0089] With respect to the CPSR message, as mentioned above there is also a similar field called the Control Plane Service Type field, which currently only takes one of the two values ​​previously indicated, namely "Mobile Originated Request" or "Mobile Terminated Request".

[0090] It should be noted that a UE that does not use CP CIoT optimization will not send a CPSR message. Instead, the UE sends a service request message when initiating a service request procedure. On the other hand, a UE that uses CP CIoT optimization sends a CPSR message when initiating a service request procedure.

[0091] Certain examples of the present disclosure provide methods and apparatus for providing emergency services to UEs in a network. The following examples may apply to and use terms associated with 3GPP 5G. For example, certain examples of the present disclosure provide methods and apparatus for enabling emergency services for UEs optimized using CP CIoT in 3GPP 5G. However, those skilled in the art will appreciate that the technology of the present disclosure is not limited to these examples or 3GPP 5G, and may be applied to any suitable system or standard, such as one or more existing and / or future generation wireless communication systems or standards.

[0092] For example, the functions of various network entities and other features disclosed herein may be applied to corresponding or equivalent entities or features in other communication systems or standards. Corresponding or equivalent entities or features may be considered as entities or features that perform the same or similar roles, functions, operations or purposes within the network. For example, the AMF functions in the following examples may be applied to other entities of any appropriate type that perform mobility management functions.

[0093] Those skilled in the art will appreciate that the present invention is not limited to the specific examples disclosed herein. For example:

[0094] The technology disclosed herein is not limited to 3GPP 5G.

[0095] One or more entities in the examples disclosed herein may be replaced with one or more alternative entities that perform equivalent or corresponding functions, processes or operations.

[0096] • One or more of the messages in the examples disclosed herein may be replaced with one or more replacement messages, signals, or other types of information carriers that convey equivalent or corresponding information.

[0097] • One or more other elements, entities and / or messages may be added to the examples disclosed herein.

[0098] • In some examples, one or more non-essential elements, entities and / or messages may be omitted.

[0099] • In one example, the functionality, process or operation of a particular entity may be divided between two or more separate entities in alternative examples.

[0100] • The functions, processes or operations of two or more separate entities in one example may be performed by a single entity in an alternative example.

[0101] • Information carried by a particular message in one example may be carried by two or more separate messages in alternative examples.

[0102] • Information carried by two or more separate messages in one example may be carried by a single message in an alternative example.

[0103] In alternative examples, the order in which operations are performed may be modified if possible.

[0104] • The transmission of information between network entities is not limited to the specific form, type and / or order of messages described in conjunction with the examples disclosed herein.

[0105] Certain examples of the present disclosure may be provided in the form of an apparatus / device / network entity and / or its method configured to perform one or more defined network functions. Certain examples of the present disclosure may be provided in the form of a system (e.g., a network) including one or more such apparatus / device / network entities and / or its method. For example, in the following examples, the network may include a UE and an AMF entity.

[0106] In view of the existing technology, there are at least the following problems:

[0107] For UEs optimized with CP CIoT, it is unclear which NAS message must be sent when requesting emergency services

[0108] A UE using CP CIoT optimization as described above will send or use a CPSR message when initiating a service request procedure. CP CIoT optimization may be supported by a UE that also supports WB-E-UTRA and may also support emergency services.

[0109] One issue is as follows: for a UE that supports WB-E-UTRA (in S1 mode or N1 mode) and is using CP CIoT optimization, it is unclear which NAS message such a UE will send when it needs to request emergency services.

[0110] As described above, a UE using CP CIoT optimization will typically only use or send a CPSR message. However, the control plane service type field of the CPSR message does not have any value for emergency services, and it is unclear whether such a UE will actually use a CPSR message or a service request message when it needs to request emergency services. Certain examples of the present disclosure address this issue by specifying UE behavior that is currently missing for this scenario.

[0111] Other issues

[0112] There are other issues associated with requesting emergency fallback when the UE is in 5GS. One issue is related to how the UE's PDU sessions will be handled once the UE transitions to EPS. In EPS, it is not possible to selectively establish user plane (UP) resources for certain PDN connections and not for other PDN connections. For example, assuming that the UE has PDN connection X and PDN connection Y, when the UE requests to establish UP resources, the network will establish UP resources for all of the UE's PDN connections (in this case, PDN connection X and PDN connection Y), assuming that these PDN connections are not only used for the control plane. In contrast, in 5GS, the UE can indicate which PDU session it wants to establish user plane resources for. Therefore, using the example provided, a UE in 5GS can, for example, request to establish UP resources for PDU session Y instead of X. This is done by setting the corresponding bits in the Uplink Data Status IE.

[0113] Therefore, when the UE transitions from 5GS to EPS, for example due to fallback for emergency services, it needs to be ensured that the UE has UP resources for all PDU sessions currently established in 5GS. Some PDU sessions in 5GS (or corresponding PDN connections in EPS) can only be established for the control plane if the UE uses control plane (CP) CIoT 5GS optimization. Using CP CIoT 5GS optimization does not necessarily mean that every PDU session will be used only for the control plane, but it may happen. It should be noted that PDU sessions used only for CP are determined to be so operated when the UE receives a Control Plane Indication IE in the PDU Session Establishment Accept message in 5GS, or when the UE receives a Control Plane Indication IE in the Activate Default EPS Bearer Context Request message. In both cases, PDU sessions or PDN connections used only for the control plane will have a Control Plane Indication IE, which will be indicated accordingly in the NAS message.

[0114] Therefore, when the UE is in EPS, due to a fallback procedure from 5GS or due to a request to use emergency services, the UE may not be able to request the establishment of UP resources, since some of the PDU Sessions / PDN Connections may be associated only with a control plane indication. Therefore, a mechanism is needed to ensure that the UE is able to use emergency services in EPS while also being able to request UP resources for all its PDN connections.

[0115] In view of the above problems, some examples of the present disclosure provide one or more of the following solutions.

[0116] Certain examples of the present disclosure provide well-defined UE behavior regarding which NAS message to use to request emergency services when the UE uses CP CIoT optimization. The UE behavior is not specified in the current related art.

[0117] In this disclosure, different conditions are disclosed based on which different NAS messages should be used by the UE.

[0118] Figure 1 An exemplary method for providing emergency services in a network that may be used in examples of the present disclosure is shown.

[0119] refer to Figure 1 , the UE identifies the need for emergency services at step 110, and determines that the UE is using CPCIoT optimization at step 130. Then, at step 150, the UE sends a NAS message including an indication requesting emergency services.

[0120] In other words, certain examples of the present disclosure provide a method for a UE in a network to request an emergency service, the method comprising: when the emergency service is needed, if the UE is using CP CIoT optimization, sending a NAS message including an indication of requesting the emergency service.

[0121] The NAS message may be a CPSR message, and the indication may be a predetermined value (eg, indicating "emergency service") in a predetermined field (eg, a control plane service type field) of the message.

[0122] The UE may be in 5GMM-IDLE mode.

[0123] The method may further include setting the RRC establishment cause to a value indicating "emergency".

[0124] The method may also include determining whether the network supports emergency services (e.g., based on a 5GS Network Feature Support IE in a registration acceptance message).

[0125] If the network does not support emergency services, the NAS message may be a CPSR message, and the indication may be a predetermined value indicating "Emergency Services Fallback" in a predetermined field of the message (eg, a Control Plane Service Type field).

[0126] The NAS message can be a service request message, and the indication can be a predetermined value in a predetermined field of the message (e.g., a service type field) (e.g., indicating "emergency service" or "emergency service fallback"), and the service request message can be sent preferentially before a message (e.g., a CPSR message) used to send data (e.g., not related to emergency services).

[0127] The method may further include sending data (e.g., CIoT user data, SMS, or location service message) (e.g., using a UL NAS TRANSPORT message) (e.g., once in 5GMM-CONNECTED mode) after completing the service request process.

[0128] The service request message may be sent preferentially based on a condition, wherein the condition includes one or more of the following: if a service request process corresponding to the service request message is being initiated to request establishment of user plane resources for a PDU session for emergency services; if a PDU session for emergency services has already been established; unless the service request process corresponding to the service request message is not initiated for emergency services or to request establishment of user plane resources for a PDU session for emergency services.

[0129] The method may also include using a service request message to switch from a first mode (e.g., 5GMM-IDLE mode) to a second mode (e.g., 5GMM-CONNECTED mode).

[0130] If the UE has a PDU session for emergency services, the transition may be performed using a Service Request message.

[0131] The method may further include: requesting establishment of user plane resources for the PDU session for the emergency service using a CPSR message or a service request message.

[0132] If the UE has a PDU session for emergency services, the service request message may be used to request establishment of user plane resources.

[0133] Figure 2 Another exemplary method for providing emergency services in a network that may be used in examples of the present disclosure is shown.

[0134] refer to Figure 2 , the UE identifies the need for emergency services in step 210, and determines that the UE is using CPCIoT optimization in step 210. Then, in step 250, the UE sets the RRC establishment cause to a value indicating "emergency", and in step 270 sends a message including the RRC establishment cause.

[0135] In other words, certain examples of the present disclosure provide a method for a UE in a network to request an emergency service, the method comprising: when the emergency service is required, if the UE is using CP CIoT optimization, setting the RRC establishment cause to a value indicating "emergency".

[0136] The UE may operate in one of the N1 mode and the S1 mode.

[0137] Figure 3 Another exemplary method for providing emergency services in a network that may be used in examples of the present disclosure is shown. Figure 3 , the network entity (eg, AMF entity) receives the message at step 310, and determines at step 330 that the RRC establishment cause is set to a value indicating "emergency" in the received message. Then, at step 350, the network entity determines that the UE is requesting emergency services.

[0138] In other words, certain examples of the present disclosure provide a method for a network entity (e.g., an AMF entity), the method comprising: determining whether the RRC establishment cause is set to a value indicating "emergency"; if the RRC establishment cause is set to a value indicating "emergency", determining that the UE is requesting emergency services.

[0139] Emergency service request by UE optimized using CP CIoT

[0140] This section defines an example of UE behavior for enabling requesting emergency services when the UE uses CP CIoT optimization. Those skilled in the art will appreciate that the examples disclosed herein can be applied not only to UEs supporting WB-E-UTRA, but also to any other RAT that can support emergency services.

[0141] In addition, those skilled in the art will appreciate that the examples disclosed herein may be applied to both N1 mode (5GS) and S1 mode (EPS). Although the examples disclosed herein relate to features and message names from 5GS, those skilled in the art will appreciate that the present invention is not limited to these examples. For example, certain examples of the present disclosure may be applied equally, correspondingly, or accordingly to S1 mode.

[0142] Solution Option 1: Define a new field for CPSR messages for emergency services

[0143] In this solution, in order to request emergency services, a new value may be defined. For example, the new value may be a control plane service type field for a CPSR message, where the new value may be, for example, "emergency services".

[0144] A UE that is using CP CIoT optimization can determine whether the network supports emergency services based on the 5GS Network Feature Support IE in the Registration Accept message.

[0145] In some examples, if the UE needs to request the use of emergency services (optionally, when in 5G MM-IDLE mode) and the UE is using CP CIoT optimization, the UE shall send a CPSR message with the control plane service type field set to "Emergency Services". In this case, the UE shall also set the RRC establishment cause to "Emergency".

[0146] In some examples, emergency services may not be supported in 5GC, and the UE will need to perform emergency services fallback as defined in [1]. For this purpose, i.e., when the UE wants to use emergency services fallback, some examples of the present disclosure may define and use a new value for the control plane service type field, such as "emergency services fallback". For this purpose, as disclosed herein, the UE may use a CPSR message and set the control plane service type field (e.g., to "emergency services fallback"). In some examples, if the UE is sending a message from 5GMM-IDLE mode, the UE should also set the RRC establishment cause to "emergency". If the UE is in 5GMM-CONNECTED mode, the UE may send a CPSR message with a new value for the control plane service type field as described above to perform emergency services fallback.

[0147] Alternatively, in certain examples of the present disclosure, even if no new value is defined for the control plane service type field, the UE may set the RRC establishment cause to "Emergency" when the UE needs to use emergency services from 5G MM-IDLE mode. Based on the RRC establishment cause received from the NG-RAN, the AMF may determine that the UE is requesting emergency services even if the UE sends a CPSR message with a control plane service type of "Mobile Originated Request", in which case the UE should do so. Therefore, the AMF behaves as if it receives a service request message with the service type field set to "Emergency Services".

[0148] In certain examples of the present disclosure, for a UE that has established a PDU session for emergency services, if the UE is in 5G MM-IDLE mode and needs to initiate a service request process for transmitting data, SMS or positioning service messages (hereinafter referred to as "data on the control plane"), the UE should send a CPSR message as specified in [1]. In this case, the UE does not need to set the RRC establishment cause to "emergency". If the UE also needs to request the establishment of user plane resources for the PDU session for emergency services, the UE should include an uplink data status IE and set the corresponding bit to, for example, "1", the corresponding bit identifying the PDU session ID associated with the PDU session for emergency services. In addition, the UE should set the RRC establishment cause to "emergency". In this case, if a new value for the control plane service type is defined as disclosed herein, the UE should also set this field to "emergency service". The same CPSR message can also carry data on the control plane.

[0149] In some examples, to request emergency fallback, e.g., to set a control plane service type field / IE, e.g., “Emergency Service Fallback,” the UE may check one or more conditions, e.g., any combination of one or more of the following conditions:

[0150] UE is using CP (control plane) CIoT 5GS optimization

[0151] The UE does not have any PDU sessions that are only used for the control plane (i.e., the UE only has PDU sessions that are not only used for the control plane)

[0152] At least one PDU session is not only used for the control plane

[0153] UE operates in single registration mode

[0154] N26 interface is available / supported in the network

[0155] UE supports data transmission on the user plane (i.e., N3 data transmission)

[0156] UE and / or network supports emergency service fallback (or fallback of emergency services)

[0157] Optionally, when the UE indicates that it supports S1 mode and optionally supports S1 data transmission

[0158] When one or more specific conditions are met (e.g., any combination of one or more of the above conditions), then as disclosed herein, a UE using control plane CIoT 5GS optimization may, for example, request an emergency fallback (e.g., by sending a CPSR and setting the control plane service type IE to "emergency service fallback," or by sending an SR message and setting the service type IE to "emergency service fallback").

[0159] Alternatively, if the UE has at least one PDU session used only for the control plane, the UE may locally disable the PDU session if the UE is in idle mode and the UE needs to send a CPSR message (or SR message) to request emergency service fallback. In this case, the UE may include a PDU session status IE and set a bit corresponding to any PDU session used only for the control plane so that the bit indicates that the PDU session is no longer active in the UE (i.e., indicating that the 5GSM state of the corresponding PDU session is PDU SESSION INACTIVE). The UE may include an uplink data status IE in the CPSR message. The UE may send a CPSR message and set the control plane service type to "emergency service fallback". Alternatively, the UE may always take the actions disclosed herein regardless of the type of PDU session, or optionally only when there is at least one PDU session used only for the control plane (so that the UE may release all its PDU sessions, even if not all of them are used only for the control plane).

[0160] If the UE is in connected mode, the UE may first release any PDU sessions used only for the control plane, for example by sending an explicit 5GSM NAS message (e.g., a PDU Session Release Request message). Once all such PDU sessions (i.e., PDU sessions used only for the control plane) are released, the UE may send a CPSR message (or SR message) to request emergency service fallback as disclosed herein. Alternatively, the UE may locally release one or more PDU sessions (e.g., as described above) and send a Registration Request, and include a PDU Session Status IE to indicate that the PDU session is released. The UE may then request emergency service fallback, for example by sending a CPSR message (or SR message), as described herein.

[0161] Alternatively, in order to use emergency services in a target system such as EPS or 2G (e.g., GERAN) or 3G (e.g., UTRAN, e.g., Iu-CS mode), the UE may autonomously reselect the target system, for example, the UE may autonomously perform idle mode to S1 mode reselection (e.g., the UE reselects or selects a cell in E-UTRA) or the UE reselects to Iu mode (e.g., Iu-CS mode) or the UE reselects a cell in a circuit switching (CS) domain or system. If the UE is in connected mode, as disclosed herein, the UE may locally release its NAS connection before reselecting the target system. In this case, the UE may locally disable any PDU sessions that are only used for the control plane; or all of its PDU sessions, regardless of whether they are only used for the control plane, may be disabled. If the UE and / or the network do not support emergency service fallback and the UE supports the CS domain (e.g., A mode or Iu-CS mode), the UE may do so.

[0162] In some examples, in order to take any of the actions disclosed above, the UE may first optionally release any of its PDU sessions, for example, locally or via explicit signaling as described herein. As described herein, when all sessions are released, the UE may send a CPSR message (or SR message) to request emergency service fallback.

[0163] Alternatively, when the UE sends a CPSR message (or SR message) requesting emergency service fallback (e.g., as disclosed herein), the AMF may take any appropriate action, such as any combination of one or more of the following actions:

[0164] If the UE has any PDU session for control plane only, the AMF may disable or release the PDU session locally and notify the SMF to release the PDU session. The AMF may send the PDU session status IE in the service accept message to indicate that the PDU session is not in an active state (i.e., indicating that the 5GSM state of the corresponding PDU session is PDU SESSION INACTIVE).

[0165] If the UE has any PDU session for control plane only, the AMF performs emergency services fallback by performing a redirection of the UE to EPS connected to 5GC (i.e. S1 mode) or to E-UTRAN (if supported). Note that UE redirection is not a handover.

[0166] If the UE has at least one PDU Session that is not only used for the control plane, the AMF may release all other PDU Sessions that are only used for the control plane. The AMF may run or perform emergency service fallback by handover or redirection.

[0167] If the UE does not have a PDU Session associated only with the control plane, the AMF may perform emergency service fallback using handover or redirection based on its policy. The AMF may first establish UP resources for all PDU Sessions not only for the control plane.

[0168] The AMF may always release the PDU Sessions for all UEs even if some of the PDU Sessions are used only for the control plane.

[0169] Optionally if the UE does not have a PDU Session for the control plane only, and / or optionally after receiving and verifying that the PDU Session Status IE would indicate so, the AMF may accept the request from the UE.

[0170] The AMF may take any combination of the actions disclosed above, optionally when the AMF supports the N26 interface, and / or optionally when the UE operates in single registration mode, and / or optionally when the UE and / or AMF support emergency services fallback, and / or optionally when the UE indicates that it supports S1 mode and optionally supports S1 data transmission.

[0171] Optionally, when accessing the target system as part of emergency services fallback, or initiating an emergency call due to autonomous UE selection / reselection into the target system (which may be on the CS domain), in some examples the UE may locally release or disable any / all of its PDU sessions, where optionally the UE may do so if the PDU sessions are used only for the control plane.

[0172] Those skilled in the art will appreciate that the above techniques may be applied in any suitable combination. Those skilled in the art will also appreciate that the above techniques are not limited to CPSR messages, and may also be applied to, for example, Registration Request messages when a Registration Request message is sent instead of a CPSR to request emergency services, as specified in 3GPP TS 24.501.

[0173] Some of the issues discussed above may also apply to situations where the UE is in EPS and needs to request emergency services. Therefore, the techniques described herein may also be applied in this case. In this case, the UE may be considered to be a UE that is using CPCIoT EPS optimization, and therefore a CPSR message (or SR message) may be sent and the control plane service type may be set to, for example, "emergency service" to request emergency services. Alternatively, the UE may send an extended service request and set the service type to "mobile initiated CS fallback emergency call or 1xCS fallback emergency call".

[0174] For example, for a UE that is using CP CIoT EPS optimization, the UE may check any suitable conditions before requesting emergency services using a CPSR message (or with an SR message), such as any combination of one or more of the following:

[0175] UE is using (control plane) CIoT EPS optimization

[0176] The UE does not have any PDU sessions that are only used for the control plane (i.e., the UE only has PDU sessions that are not only used for the control plane)

[0177] At least one PDU session is not only used for the control plane

[0178] UE operates in single registration mode

[0179] N26 interface is available / supported in the network

[0180] UE supports data transmission on the user plane (i.e., S1 data transmission)

[0181] The UE and / or network supports CSFB and optionally has negotiated the use of CSFB

[0182] When one or more specific conditions are met (e.g., any combination of one or more of the above conditions), the UE that is using CP CIoT EPS optimization and needs to use emergency services can send an SR message and set the service type IE to "emergency service". The UE can also optionally set the "active" flag in the control plane service type IE to a value of 1 to indicate "request to establish a radio bearer". The UE can also set the RRC establishment cause to "emergency".

[0183] Alternatively, if the UE has at least one PDN connection used only for the control plane, and optionally if the UE is in idle mode, and if the UE wants to send a CPSR message (or SR message) to request emergency services, the UE may locally disable the default EPS bearer of any PDN connection used only for the control plane. The UE may also locally disable any dedicated EPS bearer associated with such a PDN connection (or associated with the default EPS bearer of such a PDN connection). In this case, the UE may include an EPS bearer context status IE and set a bit corresponding to any default EPS bearer (or any dedicated EPS bearer) so that the bit indicates that the EPS bearer context is disabled in the UE (i.e., indicating that the ESM state of the corresponding EPS bearer context is BEARER CONTEXT-INACTIVE). The UE may include the EPS bearer context status IE in the CPSR message. The UE then sends a CPSR message (or SR message) to request emergency services.

[0184] If the UE is in connected mode, the UE may first release any PDN connections used only for the control plane by sending an explicit ESM NAS message (e.g., a PDNDISCONNECT REQUEST message). Once all such PDN connections (i.e., PDU connections used only for the control plane) are released, the UE may send a CPSR message (or SR message) to request emergency services, such as described herein.

[0185] Alternatively, in order to use emergency services in a target system such as 2G (e.g., GERAN) or 3G (e.g., UTRAN), the UE may autonomously reselect the target system, for example, the UE may autonomously perform idle mode reselection to, for example, UTRAN (Iu mode or Iu-CS mode), or the UE may reselect a cell in a circuit switching (CS) domain or system (in Iu mode or A mode). If the UE is in connected mode, the UE may locally release its NAS connection before reselecting to the target system, for example as described herein. In this case, the UE may locally disable any PDN connection used only for the control plane or any default (or dedicated) EPS bearers associated with a PDN connection used only for the control plane, or may disable all of its PDN connections or EPS bearers, regardless of whether they are used only for the control plane. The UE may do so if the UE and / or the network do not support CS fallback and the UE supports the CS domain (e.g., A mode or Iu-CS mode).

[0186] Alternatively, for example, if the network (e.g., EPS) does not support IMS emergency, and / or if the UE does not support emergency on the PS domain (e.g., IMS emergency), the UE using CP CIoT EPS optimization may request to use CS fallback for emergency by sending a CPSR message or an SR message and setting the service type to "Mobile originated CS fallback emergency call or 1xCS fallback emergency call". In this case, any of the above techniques may be applied. The UE may first register to use CSFB by sending a TAU or an attach request, and then request to use CSFB.

[0187] Alternatively, when the UE sends a CPSR message (or SR message) requesting emergency services (e.g., as described herein), the MME may take any appropriate action, such as any combination of one or more of the following actions:

[0188] If the UE has any PDN connections for the control plane only, the MME may locally disable or release the PDU connections for the control plane only (or the MME may disable the default EPS bearer and any dedicated EPS bearers associated with the PDN connection). The MME may send the EPS bearer context status IE in the SERVICE ACCEPT message to indicate that each EPS bearer context is disabled (i.e., indicating that the ESM state of the corresponding EPS bearer context is BEARER CONTEXT-INACTIVE).

[0189] If the UE has any PDN connection for control plane only, and if the UE sends an Extended Service Request message to request CSFB for emergency (i.e., the Service Type in the CPSR or SR message is set to “Mobile Originated CS Fallback Emergency Call or 1xCS Fallback Emergency Call”), the MME may perform CS Fallback by performing redirection of the UE to a target CS system (e.g., GERAN (A mode) or UTRAN (Iu-CS mode)).

[0190] If the UE has at least one PDN connection not only for the control plane, the MME may release all other PDN connections used only for the control plane (or release each EPS bearer used only for the control plane associated with such a PDN connection). The MME may run or perform CS fallback by handover or redirection.

[0191] The MME may always release all UE's PDN connections even if not all connections are used only for the control plane.

[0192] • Optionally if the UE has no PDN connection for the control plane only, and / or optionally after receiving and verifying that the EPS Bearer Context Status IE would indicate so, the MME may accept the request from the UE.

[0193] If the UE does not have a PDN connection associated only with the control plane, the MME may perform CS fallback using handover or redirection based on its policy. To perform CSFB with handover, the MME may first establish UP resources for all PDN connections or EPS bearers not only for the control plane.

[0194] Optionally, when accessing the target system as part of CS fallback, or due to autonomous UE selection / reselection to the target system to initiate an emergency call (which may be on the CS domain), in some examples, the UE may locally release or disable any PDN connection, where optionally, the UE may do so if the PDN connection is used only for the control plane. Alternatively, the UE may locally release or disable any EPS bearers associated with the PDN connection used only for the control plane.

[0195] Those skilled in the art will appreciate that the techniques described herein may also be applied to other NAS messages such as Tracking Area Update Request messages, and are not limited to CPSR, SR or Extended Service Request messages.

[0196] Those skilled in the art will appreciate that the techniques described herein may be applied to / applied to any suitable system, in any suitable combination.

[0197] In the present disclosure, "redirection" may include "idle mode cell redirection".

[0198] Solution Option 2: UE uses Service Request Message for Emergency Services

[0199] In this solution, when the UE needs to initiate a service request process by 5G MM-IDLE mode for emergency services, the UE can use a service request message even if the UE is using CP CIoT optimization. Therefore, even if the UE has data to be sent using a CPSR message, in this case, the UE can also give priority to sending a service request message, optionally, especially when the emergency service request is a request for an emergency fallback service. Once in connected mode, the UE can send any data (e.g., CIoT user data, SMS, or location service message) using an UL NAS TRANSPORT message after the service request process is completed.

[0200] In certain examples of the present disclosure, the service request message may always take precedence over the CPSR message as long as the UE needs to establish a PDU session for emergency services, or as long as a PDU session has already been established for emergency services. Alternatively, the UE may use a service request message to transition from 5GMM-IDLE mode to 5GMM-CONNECTED mode and establish a PDU session for emergency services. Once established, for example when the UE is in connected mode or idle mode, the UE may use the CPSR message even for the PDU session for emergency services. The UE (which is also using CP CIoT optimization) may use the CPSR message when it needs to request the establishment of user plane resources for a PDU session for emergency services.

[0201] Alternatively, in some examples of the present disclosure, when in idle mode, the UE may use or send a CPSR message as long as a service request procedure is not initiated for emergency services (including a request to establish user plane resources for a PDU session for emergency services). Otherwise, if a service request is initiated to request the establishment of user plane resources for emergency services, the UE may use a service request message.

[0202] Alternatively, in certain examples of the present disclosure, as long as the UE has a PDU session for emergency services, the UE may always use a service request message to transition from idle mode to connected mode (even if the UE has data to be sent on the control plane), or request the establishment of user plane resources for the PDU session for emergency services or all PDU sessions activated in the UE. Optionally, the CPSR message may be used only to request the establishment of user plane resources for a PDU session that is not for emergency services.

[0203] Alternatively, in some examples of the present invention, the UE may use or send a Service Request message to request emergency service fallback, while the CPSR message may be used for all requests not related to emergency services.

[0204] Those skilled in the art will appreciate that the techniques described herein can be applied to S1 mode. Although certain examples are disclosed herein in the context of 5GS, those skilled in the art will appreciate that the techniques described herein are not limited to 5GS. For example, these techniques can be applied to EPS in a similar, corresponding, or equivalent manner.

[0205] In certain examples of the present disclosure, when the UE is also using CP CIoT optimization, the UE behavior regarding requesting emergency services is specified and predictable. Therefore, it becomes clear which NAS message to use and how to set its content, and is therefore testable. Since the network can process the message in the correct way when the conditions are met, the network behavior is also specified. Otherwise, the network may regard the use of certain messages as an error and ignore them, which may cause delays in establishing any emergency services.

[0206] Figure 4 is a block diagram of exemplary network entities that may be used in examples of the present disclosure. For example, a UE, an AMF, and / or any other suitable network entity may be Figure 4 It is provided in the form of the network entity shown. Those skilled in the art will understand that Figure 4 The network entities shown in may be implemented, for example, as network elements on dedicated hardware, as software instances running on dedicated hardware, or as virtualized functions instantiated on an appropriate platform (eg, on a cloud infrastructure).

[0207] The entity 400 includes a processor (or controller) 401, a transmitter 403, and a receiver 405. The receiver 405 is configured to receive one or more messages or signals from one or more other network entities. The transmitter 403 is configured to send one or more messages or signals to one or more other network entities. The processor 401 is configured to perform one or more operations and / or functions as described above. For example, the processor 401 may be configured to perform the operations of a UE or an AMF.

[0208] The technology described herein can be implemented using any appropriately configured device and / or system. Such a device and / or system can be configured to perform a method according to any aspect, embodiment, example or claim disclosed herein. Such a device may include one or more elements, such as one or more of a receiver, a transmitter, a transceiver, a processor, a controller, a module, a unit, etc., each of which is configured to perform one or more corresponding processes, operations and / or method steps for implementing the technology described herein. For example, the operation / function of X can be performed by a module (or X module) configured to perform X. One or more elements can be implemented in the form of hardware, software, or any combination of hardware and software.

[0209] It should be understood that the examples of the present disclosure may be implemented in the form of hardware, software, or any combination of hardware and software. Any such software may be stored in the form of volatile or non-volatile memory (e.g., erasable or rewritable storage devices such as ROM), or in the form of memory such as RAM, memory chips, devices or integrated circuits, or on optical or magnetically readable media such as CDs, DVDs, disks or tapes.

[0210] It should be understood that storage devices and storage media are embodiments of machine-readable storage that are suitable for storing one or more programs including instructions that, when executed, implement certain examples of the present disclosure. Therefore, certain examples provide a program that includes code for implementing a method, apparatus, or system according to any example, embodiment, aspect, and / or claim disclosed herein, and / or a machine-readable storage storing such a program. Further, such a program may be transmitted electronically via any medium, such as a communication signal carried by a wired or wireless connection.

[0211] While the invention has been shown and described with reference to certain embodiments, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the scope of the invention as defined in any appended claims.

Claims

1. A method for initiating a service request procedure performed by a user equipment UE in a fifth generation mobility management-idle 5GMM-IDLE mode in a fifth generation system 5GS network, the method comprising: Determining that the UE is using control plane CP cellular Internet of Things CIoT optimization; as well as sending a control plane service request CPSR message including control plane service type information set to a bit value indicating “emergency service” to the network in a case where the UE has user data to be sent and a protocol data unit (PDU) session for emergency services exists, The uplink data status information element IE in the CPSR message indicates the PDU session used for the emergency service.

2. The method according to claim 1, further comprising: In the event that the 5GS network does not support the emergency service, a CPSR message is sent including control plane service type information set to a bit value indicating "emergency service fallback".

3. The method according to claim 2, in, The following condition is checked for the CPSR message including the control plane service type information set to a bit value indicating "emergency service fallback": the UE does not have any PDU session for control plane only.

4. The method according to claim 1, further comprising: Requesting establishment of user plane resources for the PDU session for the emergency service using the CPSR message including the control plane service type information set to a bit value indicating “emergency service” and the uplink data status IE indicating the PDU session for the emergency service.

5. The method according to claim 1, wherein: The UE operates in N1 mode.

6. A user equipment UE in a fifth generation mobility management-idle 5GMM-IDLE mode in a fifth generation system 5GS network for initiating a service request process, the UE comprising: Transmitter; as well as The processor is configured as: Determining that the UE is using control plane CP cellular Internet of Things CIoT optimization, and sending a control plane service request CPSR message including control plane service type information set to a bit value indicating “emergency service” to the network in a case where the UE has user data to be sent and a protocol data unit (PDU) session for emergency services exists, The uplink data status information element IE in the CPSR message indicates the PDU session used for the emergency service.

7. The UE according to claim 6, wherein: The processor is further configured to: In the event that the 5GS network does not support the emergency service, a CPSR message is sent including control plane service type information set to a bit value indicating "emergency service fallback".

8. The UE according to claim 7, wherein: The following condition is checked for a CPSR message including control plane service type information set to a bit value indicating “Emergency Service Fallback”: the UE does not have any PDU session for control plane only.

9. The UE according to claim 6, wherein: The processor is further configured to request establishment of user plane resources for the PDU session for the emergency service using the CPSR message including the control plane service type information set to a bit value indicating "emergency service" and the uplink data status IE indicating the PDU session for the emergency service.

10. The UE according to claim 6, wherein: The UE operates in N1 mode.

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