CN112352460A

CN112352460A - Method for controlling terminal for cellular IoT service in 5G mobile communication system

Info

Publication number: CN112352460A
Application number: CN201980042308.3A
Authority: CN
Inventors: 金成勋; 白令教; 孙仲济; 李淏娟
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2018-05-14
Filing date: 2019-05-14
Publication date: 2021-02-09
Anticipated expiration: 2039-05-14
Also published as: CN112352460B; KR20190130473A; KR20190130487A

Abstract

The present disclosure relates to a communication technology for merging a 5G communication system supporting a higher data transmission rate than a 4G system with an IoT technology, and a system thereof. The present disclosure may be applied to intelligent services based on 5G communication technologies and IoT related technologies, such as smart homes, smart buildings, smart cities, smart cars or networked cars, healthcare, digital education, retail, and security related services. Disclosed is a method for efficiently controlling a terminal for a cellular IoT service in a 5G mobile communication system.

Description

Method for controlling terminal for cellular IoT service in 5G mobile communication system

Technical Field

A detailed description of the embodiments of the present disclosure is provided mainly with reference to a new ran (nr) and a packet core as a radio access network and a core network (5G system, 5G core network, or next generation core network (NG core)) in a 5G mobile communication standard specified by 3 GPP. However, the subject matter of the present disclosure may be slightly modified without departing from the scope of the present disclosure, and may be applied to other communication systems having similar technical backgrounds. Modifications and applications thereof may be determined by those skilled in the art.

The CIoT service of the 5G system may support a function of transmitting data between the UE and the core network via a non-access stratum (NAS) message so that the core network transmits it to an external data network, and may support a function of transferring data transmitted from the UE to an external server through a Network Exposure Function (NEF).

Furthermore, 5G systems also provide factory automation services known as industrial IoT. Robots and other devices used for factory automation are able to communicate with each other via cellular networks and may fall within the broad category of IoT devices. These devices may require time sensitive data communication. For example, a device may need to send status information and command messages to another device over a network within 10ms, and may be configured to provide the required status information at a predetermined time or receive the required status information at a predetermined time.

In the following description, for ease of explanation, the present disclosure uses terms and names defined in the third generation partnership project long term evolution (3GPP LTE) standard. However, the present disclosure is not limited by these terms and names, and can be applied to systems conforming to other standards in the same manner.

Background

To meet the increasing demand for wireless data services since the deployment of 4G communication systems, efforts have been made to develop improved 5G communication systems or quasi-5G (pre-5G) communication systems. Accordingly, the 5G or quasi-5G communication system is also referred to as a "super 4G network" or a "post-LTE system". The 5G communication system is considered to be implemented in a higher frequency (millimeter wave) band (e.g., 60GHz band) in order to achieve a higher data rate. In order to reduce propagation loss of radio waves and increase transmission distance, beamforming, massive Multiple Input Multiple Output (MIMO), full-dimensional MIMO (FD-MIMO), array antenna, analog beamforming, massive antenna techniques are discussed in the 5G communication system. Further, in the 5G communication system, system network improvement based on advanced small cells, cloud Radio Access Network (RAN), ultra dense network, device-to-device (D2D) communication, wireless backhaul, mobile network, cooperative communication, coordinated multipoint (CoMP), reception side interference cancellation, and the like is ongoing. In the 5G system, hybrid FSK and QAM modulation (FQAM) and Sliding Window Superposition Coding (SWSC) have been developed as Advanced Coding Modulation (ACM), and filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA), and Sparse Code Multiple Access (SCMA) have also been developed as advanced access technologies.

The internet, which is a human-centric network-connected internet in which people generate and consume information, is now evolving towards the internet of things (IoT), where distributed entities, such as items, can exchange and process information without human intervention. Internet of everything (IoE) has emerged as a combination of IoT technology and big data processing technology through a connection with a cloud server. As technical elements, such as "sensing technology", "wired/wireless communication and network infrastructure", "service interface technology", and "security technology" have been required for IoT implementation, sensor networks, machine-to-machine (M2M) communication, Machine Type Communication (MTC), and the like have been recently researched. Such an IoT environment may provide an intelligent internet technology service that creates new value for human life by collecting and analyzing data generated between connected items. IoT can be applied in various fields including smart homes, smart buildings, smart cities, smart cars or networked cars, smart grids, healthcare, smart homes, and advanced medical services through fusion and integration between existing Information Technology (IT) and various industrial applications.

For this reason, various attempts have been made to apply the 5G communication system to the IoT network. For example, technologies such as sensor networks, Machine Type Communication (MTC), and machine-to-machine (M2M) communication may be implemented through beamforming, MIMO, and array antennas. The application of cloud Radio Access Networks (RANs), which are the big data processing technologies described above, can also be considered as an example of the convergence between 5G technologies and IoT technologies.

Recently, as Long Term Evolution (LTE) and LTE-Advanced (LTE-Advanced) have been developed, a method and apparatus for efficiently controlling a User Equipment (UE) in order to provide a cellular IoT service in a 5G mobile communication system are required.

Disclosure of Invention

Technical problem

In order to support a CIoT service in a 5G mobile communication system, a method of supporting the following two services is provided.

AS one of IoT-related services provided in a 5G mobile communication system, if downlink data to be transmitted to a User Equipment (UE) is scheduled at a predetermined time (e.g., 9 am on monday, 12 pm on each day, etc.), a third party application server (hereinafter referred to AS an AS) may provide corresponding scheduling information to the mobile communication network, and thus the mobile communication network can prepare data transmission to the UE at the corresponding time. The mobile communication network may perform control such that a time scheduled by the UE in the scheduling information is reachable, or may protect resources for data transmission. The present disclosure provides a method in a mobile communication network that enables a corresponding UE to maintain a state of connection to the mobile communication network at a scheduled data transmission time. This approach is particularly effective for IoT UEs, which change to a state that is not reachable by the mobile communication network to reduce the amount of power consumed. The UE performing the predetermined operation to reduce the amount of power consumed may be a UE that turns on a modem and wakes up (e.g., MICO mode) only when it has data to transmit, or a UE that operates by negotiating with a mobile communication network to reduce the amount of power consumed and cannot receive a page from the network during a predetermined period of time.

As another IoT-related service used in the 5G mobile communication system, there is an industrial IoT for factory automation. Industrial IoT requires the transmission/reception of data that is sensitive to transmission time. For example, there may be requirements, such as requiring data to be sent to the UE within 5ms, or requiring data from the UE to be transmitted to the server within 10 ms. In the case of industrial IoT, private networks can be configured and used that only the corresponding factory can use. Further, a localization server may be prepared in a predetermined area of a factory to receive data from the UE, analyze data, or transmit data to the UE. If the server sends data to the UE, the network wakes up the UE in an idle state, changes the UE into a connection state, allocates resources for data transmission, and sends the data. The process of changing the idle state to the connected state as described above may require time. AS another example, if downlink data to be transmitted to the UE is scheduled at a predetermined time (e.g., 9 am on monday, 12 am, 10 minutes from now on, etc.), an application server (hereinafter referred to AS an AS) may provide the mobile communication network with scheduling information associated with the corresponding data transmission, so the mobile communication network can prepare the data transmission to the UE at the corresponding time. The mobile communication network may perform control such that a time scheduled by the UE in the scheduling information is reachable, may enable the UE to be in a connected state such that data transmission is immediately performed, or may secure resources for data transmission to the corresponding UE before changing the UE to the connected state. The present disclosure provides a method of changing a corresponding UE to a state of being connected to a mobile communication network in advance based on a predetermined data transmission schedule or providing the UE with scheduling information indicating when to change to the state of being connected to the network in the mobile communication network.

AS another CIoT service provided in the 5G mobile communication system, a function of the UE for transmitting non-IP data to the AS via the NEF may be supported. This is the delivery of non-IP data, abbreviated as "NIDD". Alternatively, there may be a reliable data service, abbreviated as "RDS", providing a reliable data transmission service between the UE and the NEF. As described above, in order to support the function of transmitting IoT small data via the NEF, the NEF and the SMF may need to establish a connection for data transmission or may need to exchange related information. According to conventional approaches, configuration associated with NIDD is performed between a third party AS and NEF. Subsequently, if the UE establishes a PDU session associated with the NIDD service with the SMF, the SMF may perform activation of the NIDD service with the NEF. If NIDD configuration is not performed in advance between the third party AS and the NEF, information associated with NIDD configuration is not present in the network. Accordingly, the SMF may not approve the PDU session setup procedure performed by the UE and may reject the corresponding request. In addition, after NIDD configuration is performed between the third party AS and the NEF, the third party AS may need to send application layer signaling so that the UE may perform PDU session setup for NIDD service or may need to perform device triggering using the 3GPP network. To send application layer signaling before the UE establishes a PDU session for NIDD, a different PDU session than the PDU session for NIDD needs to be established. In addition, the UE needs to support SMS in order to support device triggering. In other words, the limitations of current systems require that only IoT UEs developed at low cost support additional functionality. This may worsen the activation of IoT UEs. In a case where the UE establishes a PDU session for "data transfer service via NEF" in order to establish a connection associated with "support of data transfer service via NEF" between the SMF and NEF, the present disclosure provides a procedure of completing the PDU session establishment procedure without performing NIDD configuration between a third party AS and NEF, and activating NIDD service between the SMF and NEF when NIDD configuration is subsequently performed.

As another CIoT function used in the 5G mobile communication system, there may be a low number rate control function. According to this function, the IoT UE frequently transmits a small amount of data in order to prevent network congestion. The number of data packets that the UE can transmit per hour or the amount of data that the UE can transmit per hour may be set for the network and this value may be communicated to the UE. The UE receiving the value may restrict its own data transmission based on the set value. However, this functionality is suitable for UEs using CIoT functionality and may not need to be applied to UEs using broadband communication, such as smart phones or tablets. Therefore, there is a need for a method in which a network identifies the type of UE and determines whether to apply a low rate control function. This is provided in the present disclosure.

Technical scheme

According to an aspect of the present disclosure, a method of establishing a Protocol Data Unit (PDU) session by a Session Management Function (SMF) in a wireless communication system may include: receiving a first message from an Access Management Function (AMF), the first message containing Radio Access Technology (RAT) type information indicating a RAT currently accessed by a User Equipment (UE); determining whether to apply a small data rate control function to the UE based on the RAT type information; and transmitting a second message to the AMF, the second message including information associated with whether to apply the small data rate control function to the UE.

In this instance, the small data rate control function is a function in which the UE controls transmission of small data based on a set value set in the network, and the set value may contain at least one of the number of data packets that the UE can transmit per hour and the amount of data that the UE can transmit per hour.

A Protocol Configuration Option (PCO) including the setting value may be configured, a PCO may be included in the second message and may be transmitted to the AMF, and the PCO may be included in a PDU session setup accept message and may be transmitted to the UE.

The PDU session establishment method through the SMF may include: receiving subscription information associated with the UE from a User Data Management (UDM), wherein the subscription information and the RAT type information may be considered together to determine whether to apply the small data rate control function to the UE.

The RAT type information may indicate a RAT that the UE accesses among narrowband IoT (NB-IoT), wideband EUTRAN (WB-EUTRAN), New Radio (NR), new wireless IoT (NR-IoT), and LTE for machine type communication (LTE-M).

According to another aspect of the present disclosure, a method of establishing a Protocol Data Unit (PDU) session by a User Equipment (UE) in a wireless communication system may include: transmitting a PDU session establishment request message to an Access Management Function (AMF), the PDU session establishment request message including Radio Access Technology (RAT) type information indicating a RAT to which the UE is currently accessed; receiving information indicating whether to apply a small data rate control function to the UE and determined based on the RAT type information; and controlling small data transmission of the UE according to a setting value set in the network based on information indicating whether to apply the small data rate control function to the UE.

In this instance, the setting value may include at least one of the number of data packets that the UE can transmit per hour and the amount of data that the UE can transmit per hour.

The PDU session establishment method of the UE may further include: receiving a PDU session setup accept message containing a Protocol Configuration Option (PCO) associated with the setting value.

In this example, whether to apply the small data rate control function to the UE may be determined based on subscription information associated with the UE and the RAT type information provided from a User Data Management (UDM).

According to another aspect of the present disclosure, a Session Management Function (SMF) for establishing a Protocol Data Unit (PDU) session in a wireless communication system may include: a transceiver; and a controller configured to: performing control to receive a first message containing Radio Access Technology (RAT) type information indicating a RAT currently accessed by a User Equipment (UE) from an Access Management Function (AMF); determining whether to apply a small data rate control function to the UE based on the RAT type information; and performing control to transmit a second message containing information associated with whether to apply the small data rate control function to the UE to the AMF.

According to another aspect of the present disclosure, a User Equipment (UE) for establishing a Protocol Data Unit (PDU) session in a wireless communication system may include: a transceiver; and a controller configured to: performing control to transmit a PDU session establishment request message containing Radio Access Technology (RAT) type information indicating a RAT currently accessed by the UE to an Access Management Function (AMF); performing control to receive information indicating whether to apply a small data rate control function to the UE and determined based on the RAT type information; and controlling small data transmission of the UE according to a setting value set in the network based on information indicating whether to apply the small data rate control function to the UE.

Advantageous technical effects

According to the present disclosure, a 5G system may support an operation of connecting a User Equipment (UE) to a network at a time scheduled in a schedule in order to transmit data to the UE according to a schedule requested from a third party AS providing an application service. Accordingly, the UE wakes up at a predetermined time and connects to the network by connecting to the 3GPP network only without any additional operation of controlling the operation of the UE.

According to the present disclosure, the 5G system can activate the NIDD service by removing the dependency between the PDU session setup procedure for NIDD performed by the UE and the NIDD configuration procedure performed between the third party AS and the NEF, regardless of the order of the PDU session setup procedure and the NIDD configuration procedure.

Further, this may not require support for application layer signaling or other additional functionality to enable the UE to use NIDD services. Furthermore, this may not need to rely on another functionality to enable the 5G system to support the NIDD service of the UE.

According to the present disclosure, the 5G system may maintain the UE in a state of being connected to the network for a predetermined time in order to support a time-sensitive mobile communication service (e.g., factory automation IoT).

According to the present disclosure, the 5G system may determine a UE to which a CIoT function needs to be applied, and may determine to apply only a small data rate control function to the corresponding UE. Thus, a UE using broadband mobile data, such as a smartphone or tablet, may not be limited by small data rate control.

Drawings

Fig. 1 is a diagram illustrating a method in which an AMF acquires scheduling information associated with scheduled data transmission and provides a corresponding time to a User Equipment (UE), according to an embodiment of the present disclosure;

fig. 2 is a diagram illustrating operations performed when a UE is already in an unreachable state in a case where an AMF acquires scheduling information associated with scheduled data transmissions, according to an embodiment of the present disclosure;

fig. 3 is a diagram illustrating operations performed when a UE is already in an unreachable state in a situation in which an SMF provides scheduling information associated with scheduled data transmissions to an AMF, according to an embodiment of the present disclosure;

fig. 4 is a diagram illustrating a method in which, when a UE and an SMF perform setup of a PDU session associated with a NIDD, the SMF recognizes that no NIDD configuration exists and allows a corresponding PDU session setup request but performs deactivation, according to an embodiment of the present disclosure;

fig. 5 is a diagram illustrating an operation in which, when a PDU session is established, the SMF determines whether to apply a small data rate control based on information received from the AMF, UDM, or PCF and reports it to the UE, according to an embodiment of the present disclosure;

fig. 6 is a diagram illustrating an operation in which, when a UE changes a RAT type, the UE reports it to an SMF, which determines whether to apply a small data rate control based on the changed RAT type and informs it to the UE, according to an embodiment of the present disclosure;

fig. 7 is a diagram illustrating a structure of a UE according to an embodiment of the present disclosure; and

fig. 8 is a diagram illustrating a structure of a network entity according to an embodiment of the present disclosure.

Detailed Description

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description of the present disclosure, a detailed description of known functions or configurations incorporated herein will be omitted when it may make the subject matter of the present disclosure rather unclear. Terms to be described below are terms defined in consideration of functions in the present disclosure, and may be different according to a user, a user intention, or a habit. Therefore, the definition of the terms should be based on the contents of the entire specification.

Advantages and features of the present disclosure and methods of accomplishing the same will become apparent by reference to the following detailed description of embodiments taken in conjunction with the accompanying drawings. However, the present disclosure is not limited to the embodiments set forth below, but may be implemented in various different forms. The following examples are provided only for complete disclosure of the present disclosure and to inform those skilled in the art of the scope of the present disclosure and the present disclosure is defined only by the scope of the appended claims. Throughout the specification, the same or similar reference numbers designate the same or similar elements.

The entities used in the present disclosure are as follows.

A User Equipment (UE) is connected to a Radio Access Network (RAN) and accesses a device that performs the mobility management functions of a 5G core network device. In this disclosure, this is referred to as an access and mobility management function (AMF). This may be a function or device responsible for both access to the RAN and mobility management of the UE.

The SMF is the name of a network function that performs a session management function. The AMF connects to a Session Management Function (SMF), which routes session related messages associated with the UE to the SMF. The SMF is connected to a User Plane Function (UPF), allocates user plane resources to be provided to the UE, and establishes a tunnel for data transmission between a Base Station (BS) and the UPF.

NRF, which is an abbreviation of network repository function, stores information associated with NF installed in a mobile communication carrier network and reports the information associated therewith. NRF is linked to all NFs. When operating in the operator network, each NF performs registration on the NRF, and the NRF knows that the corresponding NF is operating in the network.

The NEF, which is an abbreviation of network exposure function, performs a function of externally disclosing internal functions and services of a mobile communication operator network. Thus, the NEF connects to an external Application Server (AS) so that the NEF transmits to the AS events or information occurring from NFs in the network or transmits events or information requested from the AS to the internal NFs.

UDR is an abbreviation for subscriber data repository and performs the same functions as HSS of 4G networks. It may store subscription information of the UE or a context used by the UE in the network.

As a background of the present disclosure, a function of supporting a CIoT service is as follows.

Function of data transmission via control plane signaling: IoT UEs transmit or receive small amounts of data, and therefore, establishing a user plane connection for small amounts of data transmission or reception is inefficient in terms of the use of radio resources, and signaling of user plane connection establishment always occurs, which is also inefficient.

Accordingly, techniques have been developed to transmit a small amount of data from a UE for CIoT service via control plane signaling. According to the technique, the UE may include data that is desired to be transmitted in the SM-NAS message sent to the SMF and may transmit it. The SMF receiving the data may transmit the corresponding data to the destination NF and support data transmission.

In the same way, if the data comes from the outside, the UPF or NEF may report to the SMF that data directed to the UE has arrived and transmit the corresponding data to the SMF. The SMF receiving the data may include the corresponding data in an SM-NAS message transmitted to the UE and transmit it to the UE. For data transmission as described above, the UE and SMF need to establish a PDU session, and the PDU session is used for data transmission functions via control plane signaling. Accordingly, in case of establishing a PDU session with SMF, the UE may perform the procedure by including an indicator indicating a data transmission function via control plane signaling in the procedure.

non-IP data transport services via NEF: the 5G mobile communication network may transfer non-IP data transmitted from the UE to the third party AS via the NEF. The UE may include the non-IP data in a NAS message to be sent to the SMF and send it to the SMF, which may send it to the NEF. The NEF may send it to the AS. If the AS sends data, the AS sends non-IP data associated with the UE to the NEF, and the NEF may send it to the SMF. The SMF may include the data in a NAS message and send it to the UE.

That is, the data route is UE-AMF-SMF-NEF-AS. A process of providing a data transmission service to a predetermined UE and a predetermined AS via the NEF for non-IP data transmission for the IoT service is referred to AS a "NIDD service".

non-IP data is any form of transport protocol other than IP format. The non-IP data may be used in order to reduce the capacity of an excessive IP header compared to actual data, and may be a protocol for simple data transmission, such as a sensor network or the like. In addition, since the UE transmits data to the AS via the NEF, a protocol between the UE and the NEF may be used. This protocol supports reliable data transmission between the UE and the NEF and is therefore referred to as a reliable data service, abbreviated RDS.

In other words, the service of transmitting data via NEF is called "NIDD" or "RDS" in the 3GPP standard, and may be called by other names. However, the function of performing data transmission via the NEF corresponds to "a service of transmitting data via the NEF" used in the present disclosure, regardless of its name. In this disclosure, a process for providing NIDD services via SMF is described.

Therefore, in order to use NEF and NIDD services, the UE may need to perform a PDU session setup procedure with the SMF. The PDU session setup procedure is a procedure associated with a predetermined data network performed between the UE and the SMF. If the PDU session is for NIDD service, the UE may perform a PDU session setup procedure with the SMF by including an indicator corresponding to the NIDD service or a data network name associated with the NIDD service in the procedure.

Support service for scheduled data transmission (scheduled downlink data communication service): the 5G mobile communication network may receive scheduling information associated with scheduled downlink data transmission times of predetermined UEs or groups from a third party AS. The third party AS is an application server that exists outside the scope of the 5G mobile communication network element.

For example, in a case where the industrial IoT supports data transfer using a 5G mobile communication system, an application server operating for an industrial IoT service may be considered a third party AS from the perspective of the 5G mobile communication system. The third party AS may provide scheduling information or the time the UE needs to be available for data reception (i.e. the time the UE may arrive at the network, be able to receive pages or need to be in a connected state) to the 3GPP network via the NEF via the "expected UE behavior" of the provisioning API. The scheduling information may include a plurality of pieces of scheduling information. The pieces of scheduling information may be, for example, 9 am on monday, 12 am each day, 10 hours after the current time, 20 minutes after the current time, and the like.

The network receiving it may perform configuration such that when the UE desires to use a power saving state (a state in which the UE is not reachable from the network in order to reduce power consumption, that is, a state in which the UE does not perform operations related to network connection, such as a state in which the paging channel is not monitored, etc.), the network can detect the UE (reachable) at the scheduled communication time.

For example, by comparing the scheduled airtime with a time at which the UE periodically reports reachability to the network (e.g., a periodic registration update timer), the network may set a subsequent periodic registration update time appropriate for the scheduled airtime. As another example, if the scheduled communication time is before the subsequent periodic registration update time of the UE, the network does not allow the power saving function of the UE so that the UE is reachable at the corresponding time.

Alternatively, in the case where the UE uses the industrial IoT service, that is, where the subscription information of the UE indicates that the UE is for industrial IoT, or indicates that the UE uses a private network established for industrial IoT, or the 5G network operates only for industrial IoT, the 5G network receiving the scheduling information from the AS may determine that the corresponding UE will use time-sensitive data communication.

Accordingly, the 5G network may perform configuration such that the UE is ready for data transmission/reception at a time scheduled in the scheduling information received from the AS. For example, based on scheduling information received from the AS associated with data transmission, e.g., 9 am monday, 12 pm per day, 10 minutes after the current time, etc., the 5G network may configure the scheduling information for the UE such that the UE changes to a connected state based on the corresponding schedule, or may perform paging of the UE such that the UE changes to a connected state immediately prior to the corresponding schedule.

Fig. 1 illustrates a method in which an AMF acquires scheduling information associated with scheduled data transmission and provides a corresponding time to a UE according to an embodiment of the present disclosure.

The third party application server or AS may set the scheduled communication time of the 5G network. The AS may send it by sending a message directly to the UDM or AMF, or may send the corresponding information to the UDM, AMF or SMF via the NEF. The AS may configure the scheduled communication time AS a plurality of schedules and may transmit them.

For example, the AS may send multiple pieces of scheduling information to the 5G network, such AS 0: 00. 12 parts per day: 30 or 20 minutes after the current time, or an absolute time value indicating the time after the current time (e.g., 7 months and 10 days in 2018, UTC 20: 00).

Referring to fig. 1, the present disclosure assumes that a scheduled communication time is stored in a context associated with a User Equipment (UE)110 contained in a UDM, and in operations S101 and S103, an AMF120 or an SMF130 may acquire the scheduled communication time.

Alternatively, in operations S101 and S103 of fig. 1, the NEF directly transmits the scheduled communication time associated with the predetermined UE to the AMF120 or the SMF130 so that the AMF120 or the SMF130 can obtain a corresponding value. The UDM may classify the corresponding information obtained from the NEF into a session management context and may store it.

Providing the scheduled communication time from the third party to the UDM in association with the predetermined UE indicated by the external ID or the external group ID. Thus, the UDM may store the scheduled communication time value for each external ID or external group ID of the UE in the SM context. This is because the UE has multiple external IDs or external group IDs. Alternatively, the scheduled communication time may be provided to the UDM from a third party as a value associated with a predetermined Data Network Name (DNN) of the predetermined UE indicated by the external ID or the external group ID. In this case, the UDM may store the scheduled airtime value based on the DNN value of each external ID or external group ID of the UE in the SM context. This is to support the following scenario: where the UE has multiple external IDs or external group IDs, or where subscription information is set to enable the UE to use multiple DNNs for NIDD services.

That is, the scheduled communication time is configured for each UE in the subscription information in the UDM, and a plurality of pieces of scheduled communication time information may be configured for each external ID or external group ID, or for each external ID or external group ID and each DNN.

Operation S105 is a subsequent operation performed after the SMF130 obtains a scheduled communication time, which is an SM context associated with the UE110, from the UDM, or after the SMF130 obtains a predetermined communication time from the NEF. The SMF130 may determine when to perform downlink data transmission to the corresponding UE110 based on the scheduled communication time. Since the network needs to be reachable to UE110 at a corresponding time 5G, SMF130 may send a message requesting reachability of UE110 to AMF120, which is responsible for mobility management of the UE. If the message is one of the APIs provided by the AMF120 and includes a meaning that the SMF130 requests the AMF120 to enable reachability of a predetermined UE at a scheduled communication time, any message may be used as this message in the present disclosure, although the name of the message is different from that of the message of operation S105.

In operation S105, the SMF130 may contain an ID of the UE110 (an ID enabling the AMF to identify the UE, for example, a subscription hidden identifier (SUCI) or a subscription permanent identifier (SUPI) (previous IMSI), or an external ID), may contain the scheduled communication time obtained in operation S103, and may contain a PDU session ID indicating a corresponding PDU session. The reason why the PDU session ID is included is that if the UE110 performs data communication using a plurality of PDU sessions, the UE110 needs to determine a PDU session to be activated when the UE110 transmits a service request at a scheduled communication time and wakes up. In addition, if the UE performs data communication using a plurality of PDU sessions, the AMF120 may need to identify a PDU session associated with a scheduled communication time. If the AMF120 receives a plurality of scheduled airtime values from a plurality of SMFs or a single SMF, the AMF120 may use the PDU session ID included in the message of operation S105 in order to identify the scheduled airtime value of each PDU session.

The AMF120 receiving the message of operation S105 or the AMF120 identifying the scheduled communication time associated with the UE110 via operation S101 may store corresponding information in the context of the UE 110. If UE110 requests operation to leave an reachable to network state during a predetermined period of time in order to reduce the amount of power consumed, AMF120 may use the scheduled airtime value, enabling UE110 to wake up at a predetermined time and be reachable by the network. Alternatively, if UE110 uses time-sensitive data communication, AMF120 may enable UE110 to change to a connected state at a scheduled time in the scheduling information based on a scheduled communication time value.

The UE110 may suspend operation of monitoring the paging channel (e.g., MICO mode, PSM in a 4G system) or monitor the paging channel only for a predetermined time (e.g., idle mode DRX) in order to reduce the amount of power consumed. To this end, UE110 may negotiate with AMF120 and may perform the negotiation via a registration procedure.

In operation S107, the UE110 negotiates the use of the MICO mode. However, this may inclusively include the use of other functions that UE110 needs to negotiate with AMF120 in order to reduce the amount of power consumed. For example, there may be a 5G power save mode, 5G DRX, 5G extended DRX, etc.

For ease of explanation, the description will be provided with reference to the MICO mode. The MICO mode is the following: wherein when UE110 changes to idle mode, the UE no longer monitors all paging channels and UE110 is not detectable in the 5G network. That is, the MICO mode is a mode in which the UE110 changes to an unreachable state. If UE110 needs to send data or signaling, UE110 may wake up at a periodic registration update time set by the network and may access the 5G network again. Thus, the network does not wake up the UE110 until a registration procedure performed at the UE110 at a periodically set time occurs. The UE 100 may include an indicator indicating that the UE will use the MICO mode during the registration request process of operation S107.

In addition to negotiating with the AMF120 in order to reduce the amount of power consumed, operation S107 may be a registration procedure performed based on the mobility of the UE110, or may be a registration procedure performed at a periodic time. Further, the operation may be a registration procedure performed by UE110 to synchronize with the network. This operation may include all cases where UE110 performs a registration procedure with AMF120 under other conditions.

In operation S109, the AMF120 may determine whether the MICO mode of the UE110 is allowed. If the scheduled communication time value of the UE110 will come soon, the AMF120 may disallow the MICO mode of the UE110, so that the UE110 does not enter the MICO mode and continuously remains in the reachable state.

If the scheduled communication time value for UE110 will arrive a sufficient amount of time after UE110 enters the MICO mode, AMF120 may allow the MICO mode so that UE110 can enter the MICO mode and reduce the amount of power consumed. Alternatively, if the UE110 uses time-sensitive data communication, operation S109 may be omitted. If time sensitive data communication is used, the function of reducing the amount of power consumed may not be used. Accordingly, the AMF120 does not determine whether the MICO mode is allowed or not, and may perform operation S111 with respect to the UE 110.

In operation S111 according to an embodiment of the present disclosure, the AMF120 may set a wake-up time of the UE110 for which the MICO mode is allowed. Alternatively, the AMF120 may set the wake-up time for normal UEs that do not use the MICO mode or UEs that use time-sensitive data communication. The wake-up time may be set based on a predetermined communication time value, and the AMF120 may set a value indicating a time slightly earlier than the scheduled communication time. In the above manner, a delay may occur when considering that the UE110 accesses the network. The wake-up time provided to UE110 may be expressed as an absolute time. For example, the wake-up time may be expressed as universal coordinated time (UTC). The time value may be set to year/month/day/minute. Alternatively, the wake-up time may be expressed as a value corresponding to a time zone of a network to which the UE is currently accessing.

For example, if it is korea, the wake-up time may be expressed by KST and the time value may be set to year/month/day/minute. Along with the wake-up time, an indicator indicating whether the corresponding time is based on UTC or on a time zone in which the UE currently accesses the network may be included. The UE can distinguish between them and, if the UE moves to a country belonging to a different time zone, another time zone can be applied appropriately. For example, in a case where the UE moves from korea to china, the UE may use the same value if UTC is used. However, if the UE receives a value corresponding to KST, the UE needs to change the value to CST corresponding to the standard time of china. The wake-up time is not limited by name and may be information provided from the AMF and indicating a time at which the UE needs to be reachable by the network. In other words, the wake-up time is information indicating a time when the UE needs to change to a state of monitoring a paging channel, or a time when the UE needs to change to a connected state by performing a service request or a registration update procedure with the network, or the like.

The wakeup time may include a plurality of pieces of scheduling information. For example, multiple pieces of scheduling information expressed as absolute time values may be included, such as 13: 00. 9 on X days of month X: 00, and so on. As another example, multiple pieces of scheduling information may be included that are not expressed as absolute time values, such as at 9 o 'clock per day, 0 o' clock monday morning, or z minutes after the current time, etc.

In operation S113, the AMF120 may transmit the wake-up time determined in operation S111 and an indicator indicating that the MICO mode is allowed to the UE 110. In case that the UE uses time-sensitive data communication, the AMF120 may transmit the wake-up time determined in operation S111 regardless of whether the MICO mode is allowed. The UE110 receiving the request may determine that the UE itself needs to be reachable by the network, may send a service request to change to a connected state, or may determine to perform a registration update procedure.

The modem of the UE110 continuously stores time information and may perform a predetermined operation when a corresponding time arrives. The time value indicating the time that has elapsed is no longer valid. If UE110 receives time values associated with multiple schedules, UE110 may determine that the time value indicating the time that has elapsed is invalid, may determine that the time value indicating the time that has not arrived is valid information, and may check whether the corresponding time has arrived.

In operation S115, the UE110 reports completion of the registration procedure. This may be performed when an ID (e.g., 5G-GUTI) associated with UE110 is newly assigned, etc., or may be omitted in order to simplify the procedure.

Upon completion of the registration procedure, the UE110 allowed to operate in the MICO mode may change to an IDLE (IDLE) state and operate in the MICO mode. When UE110 is operating in the MICO mode, the network cannot page UE 110. If UE110 is operating with a long DRX cycle (cycle) rather than a MICO mode, the network may not be able to page UE110 while UE110 is operating with a DRX sleep cycle. However, if the UE has data or signaling to send to the network, the UE110 may wake up at any time and may communicate with the network according to operation 6. This operation may not affect the wake-up time value.

However, if there is a scheduled communication time value newly set for the AMF120 while performing operation S117, the AMF120 may update the wake-up time of the UE 110. Via the registration procedure or the UE configuration update procedure, AMF120 may send a new wake-up time to UE110, and UE110 may replace the existing value with the newly received wake-up time value. The above relates to exception handling and is not shown in the drawings of the present disclosure, but may occur during operation S117.

According to an embodiment of the present disclosure, the UE110 may wake up to be reachable through the network at a time corresponding to the set wake-up time. The modem of the UE110 continuously stores the time information and may perform a predetermined operation when a corresponding time arrives. The time value indicating the time that has elapsed is no longer valid. If UE110 receives time values associated with multiple schedules, UE110 determines that the time value indicating the time that has elapsed is invalid, determines that the time value indicating the time that has not arrived is valid information, and checks whether the corresponding time has arrived.

The operations performed by UE110 to be reachable through the network may be two operations as follows. First, UE110 sends a service request or registration request to AMF 120. UE110 may wake up and access the network and may send a service request or a registration request to change to a connected state. The AMF120 receiving it may change the UE110 to a connected state and may trigger the corresponding SMF130 suitable for the PDU session or DNN in which the scheduled communication time is set in order to activate the user plane of the UE110 or the data path of the UE and thus perform scheduled downlink data transmission.

Second, UE110 enables listening to the paging channel. Since scheduled downlink communications are planned, the AMF120 may perform paging for the UE110 if downlink data is received for the UE110 at a corresponding time. Accordingly, the UE110 monitors the paging channel for a predetermined period of time from the wake-up time, and if downlink data arrives at the scheduled time, the UE110 receives a page from the AMF120 and transmits a service request. If there is no paging within a predetermined period of time, the UE returns to the power saving state again. In this example, UE110 maintains the CM-IDLE state. The predetermined period of time is based on basically setting values for the UE 110. Alternatively, in operation S113, the AMF120 may transmit information associated with a period in which the UE110 needs to listen to the paging channel to the UE110, and the UE110 may perform an operation based on the information.

Operation S121 indicates that downlink data is received as scheduled at the scheduled communication time. UPF 140 receives downlink data from the data network, reports it to SMF130, and activates the data path for transmitting data to UE 110. In response to the NW-initiated service request, the procedure is performed in operation S123. In response to the NW-initiated service request, the network performs paging of UE110, the waking UE sends the service request and UE110 changes to the connected state.

Alternatively, if the UE110 first transmits a service request in operation S123, the AMF120 determines an SMF that sets a scheduled communication time matching a corresponding time, triggers the corresponding SMF130 to activate a data path, and transmits downlink data via the activated PDU session. Alternatively, if the UE110 transmits the registration request in operation S123, the AMF120 maintains the connection of the UE110 for a predetermined period of time until receiving the downlink data notification associated with the UE 110. If UE110 returns to the idle state, UE110 becomes unreachable.

If downlink data arrives for UE110 while maintaining the connection of UE110, and SMF130 reports to AMF120 that the data path associated with UE110 needs to be activated, AMF120 may perform a procedure of activating the corresponding data path. As another example, the UE110 may include information associated with a PDU session whose data path is to be activated in a "PDU session to be activated" and a registration request, and the AMF120 receiving it may trigger the SMF130 associated with the corresponding PDU session to activate the data path at operation S123. After activating a data path for transmitting data to the UE via these three operations, the data is transmitted to the UE in operation S125.

As another example of fig. 1, although not shown, the UE110 may request a long DRX different from the MICO mode or other power saving mode in operation S107. Considering a long DRX cycle desired by the UE110, if the AMF 130 determines that the time at which the UE110 will wake up arrives after the scheduled communication time, the AMF 130 may set the DRX cycle of the UE110 such that the UE110 wakes up at a time corresponding to the scheduled communication time and may transmit it to the UE 110. UE110 may operate according to the DRX cycle provided by AMF 120.

As another example of fig. 1, the AMF120, which receives the scheduled communication time in operation S101 or S105, may perform the following operation, instead of configuring the wake-up time for the UE 110. AMF120 may determine a time when UE110 will be in a connected state to the network based on the scheduled communication time. The AS starts transmitting data to the UE110 according to the scheduled communication time. In this instance, the UE110 needs to be in a state of being connected to the network so that downlink data generated at a scheduled time is transmitted without delay. In general, if downlink data is generated for the UE110 in the idle state, the AS performs paging of the UE110 to change the UE110 from the idle state to the connected state, and allocates resources for data transmission or reception to the UE 110. However, when generating downlink data, if the UE110 is already in a connected state before generating the downlink data and the corresponding UE110 receives resources allocated in association with a PDU session in which data is transmitted at a scheduled communication time, data transmission may be immediately performed without delay due to an idle-to-connected state change operation. Therefore, it is suitable to provide a communication service with low delay to the UE 110.

AMF120 identifies the received scheduled communication time and sends a page to UE110 before the corresponding time is reached, causing UE110 to access the network and change to a connected state. The AMF120 may desire to perform downlink data transmission with respect to the UE110 at the scheduled communication time. The AMF120 having received the scheduled communication time determines a PDU session in which downlink data transmission is to be performed, based on the PDU session ID corresponding to the scheduled communication time, in operation S105. If there is information of multiple scheduled airtimes for multiple PDU sessions, the AMF120 may determine to simultaneously activate PDU sessions with similar scheduled airtime values.

Based on the determination, AMF120 may send a page to wake up UE 110. The AMF120 may send the paging message to the UE110 prior to the scheduled communication time (e.g., a few seconds prior to the scheduled communication time), or may calculate an amount of time that the UE110 typically remains in a connected state, and may send the paging message within the calculated time prior to the time set for the scheduled communication time (e.g., if the UE typically remains in a connected state one minute, or less prior to the scheduled communication time value).

If there are UEs 110 whose scheduled communication time is set to a predetermined scheduled communication time or its vicinity (for example, within several seconds) among the UEs managed by the AMF120, the AMF120 may sequentially perform paging of the UEs 110 to prevent the corresponding UEs from immediately waking up and accessing the network via paging. This can prevent the network from being congested when a large number of UEs simultaneously attempt network access at a predetermined point of time. In other words, if 100 UEs need to wake up at a predetermined scheduled communication time, pages are not transmitted to the 100 UEs at the same time, but are sequentially transmitted to a plurality of UEs, a dozen or so UEs, tens of UEs, or the like at fixed intervals. The fixed interval is based on the value set in the AMF. The UE that receives the paging sends a service request message to the network and starts to change to a connected state. The AMF120 receiving the service request transmitted from the UE110 may identify a PDU session ID for which a scheduled communication time is set in association with the corresponding UE around the corresponding time, and may start a PDU session activation procedure for the SMF130 corresponding to the corresponding PDU session ID. If there are a plurality of PDU session IDs for which a scheduled communication time is set around the time when the UE110 transmits the service request, the AMF120 may start the PDU session activation procedure for all SMFs corresponding to the PDU session IDs.

This process may be a service operation named "Nsmf _ pdusesion _ UpdateSMContext _ Request". Alternatively, the procedure may be a message called another name that the AMF sends to the SMF for PDU session activation. The SMF130 receiving the message may select the UPF 140 for PDU session activation and may perform an operation of establishing a tunnel between the base station and the UPF 140. Subsequently, a message for resource allocation is sent to the base station, and the base station allocates radio resources associated with the corresponding PDU session to the UE 110. All operations may be performed before the scheduled communication time, and when the scheduled communication time is reached, data transmission is performed in the previous PDU session. If the scheduled communication time is reached when an operation is performed in response to a service request, the AMF and the SMF may perform the same operation as described above.

Alternatively, if the scheduled communication time is not set for the predetermined session, the AMF120, which receives the scheduled communication time in operation S101, may perform the following operation. The AMF120 may not be able to identify the scheduled communication time associated with the scheduled PDU session. Accordingly, the UE110 may perform an operation of enabling the UE110 to be in a state of being connected to the network at the set scheduled communication time. Accordingly, the AMF120 may send a page to wake up the UE 110.

The AMF120 may send the paging message to the UE110 prior to the scheduled communication time (e.g., a few seconds prior to the scheduled communication time), or may calculate an amount of time that the UE110 typically remains in a connected state, and may send the paging message within the calculated time prior to the time set for the scheduled communication time (e.g., if the UE typically remains in a connected state one minute, or less prior to the scheduled communication time value).

If there are UEs whose scheduled communication time is set to a predetermined scheduled time or its vicinity (for example, within several seconds) among the UEs managed by the AMF120, the AMF120 may sequentially perform paging for the corresponding UE110 to prevent the corresponding UE from immediately waking up and accessing the network via paging. This can prevent the network from being congested when a large number of UEs simultaneously attempt network access. In other words, if 100 UEs need to wake up at a predetermined scheduled communication time, pages are not transmitted to the 100 UEs at the same time, but are sequentially transmitted to several UEs, dozens of UEs, tens of UEs, etc. at fixed intervals. The fixed interval is based on the value set in the AMF. The UE110 receiving the page sends a service request to the AMF120 and changes to a state of being connected to the network. The AMF120 receiving the service request transmitted from the UE110 may perform one of the following two operations.

First, the AMF120, which determines that the UE110 is a UE supporting low-delay communication, may start the PDU session activation procedure for all PDU session contexts stored in the context of the UE 110. That is, the AMF120 may start a service operation activated for the PDU session for all PDU sessions established by the UE110 but changed to be deactivated when the UE changes to the idle state.

Accordingly, the AMF120 may transmit a message for PDU session activation to the SMF130 serving the corresponding session for all PDU sessions included in the context of the UE 110. This may be a service operation, such as Nsmf _ pdusesion _ UpdateSMContext _ Requst. The SMF130 receiving it may perform a PDU session activation procedure with the UPF and the base station, and resources for the corresponding PDU session are allocated to the UE 110.

Since downlink data is to be generated for one of the PDU sessions that the UE110 has at the scheduled communication time and resources for the corresponding PDU session have been allocated, the UE110 can immediately receive the data. The operation corresponding to "first" may reduce delay caused by an operation of paging the UE110 and an operation in which the UE110 transmits a service request in response thereto, changes to a state of being connected to a network, and performs a PDU session activation procedure of the corresponding UE. That is, since all PDU sessions are activated before downlink data is generated, when downlink data for the UE110 is generated, the data can be immediately transmitted without a delay associated with the PDU session activation procedure.

Second, the AMF120 may maintain a state in which the UE110 has a control plane connection established with the AMF120 without an active PDU session. That is, in a state in which the UE110 has a control plane connection established with the AMF120 by transmitting a service request, the AMF120 may continuously maintain the UE110 in a connected state without performing a PDU session activation procedure. When the scheduled communication time arrives, downlink data may be transmitted to the UE110, and the data may be first transmitted to a UPF serving a PDU session corresponding to the UE 110.

The UPF 140 may report downlink data arrival for the corresponding UE to the SMF associated with the corresponding PDU session. The SMF130 receiving it may perform a PDU session activation procedure with the UPF 140 and the base station and resources for the corresponding PDU session are allocated to the UE 110. Downlink data may be transmitted to the UE110 after the PDU session activation procedure. An operation corresponding to "second" may achieve low latency by removing a procedure in which AMF120 performs paging of UE110 and UE110 wakes up via a service request. However, delays caused by the process of establishing a PDU session may be unavoidable.

Fig. 2 is a diagram illustrating operations performed when a UE is already in an unreachable state in a case where an AMF obtains scheduling information associated with scheduled data transmission according to an embodiment of the present disclosure.

According to the embodiment disclosed in fig. 2, although the third party AS 240 sets the scheduled communication time for the UE, in the case where the UE is in the low power mode and is not reachable through the network (e.g., the MICO mode), the AMF210 may not enable the UE to be reachable at the scheduled communication time.

For example, if the time corresponding to the scheduled communication time is earlier than the time at which the UE is expected to wake up, the AMF210 may not confirm whether the UE is awake before the scheduled communication time. Therefore, the AMF210 cannot ensure reachability of the UE, and can transmit information associated with a time at which the UE is expected to be reachable to a third party via the 5G system.

Referring to fig. 2, the AMF210 has had a scheduled communication time in operation S201. This information may be included in the UE context transmitted from UDM 220 or may be information transmitted directly from NEF 230.

In operation S203, the AMF210 may determine that the UE is already in the MICO mode, and more particularly, in a state of being unreachable through the network due to the low power mode. In addition, the AMF210 may determine when the UE is reachable based on a periodic registration update timer set for the UE.

If the time corresponding to the scheduled communication time is earlier than the time at which the UE is expected to wake up, the AMF210 may not confirm whether the UE is awake at or before the scheduled communication time. Accordingly, the AMF210 may not configure the UE based on the scheduled communication time. The AMF210 may perform operation S205 to report the above information to the third party AS 240.

In operation S205, the AMF210 may transmit information indicating that the UE is not currently reachable and time information associated with when the UE is expected to be reachable to the NEF 230 via the UDM 220. Alternatively, the AMF210 may transmit information indicating that the UE is not currently reachable and time information associated with a time at which the UE is expected to be reachable directly to the NEF 230.

The AMF210 may know the NEF from which information is received in operation S201, and thus may transmit the information to the corresponding NEF. The information in operation S205 may include a UE ID (e.g., an external ID) and a time when the UE is expected to be reachable. A time when the UE is expected to be reachable is determined based on a periodic registration update timer. The UE may wake up at a time corresponding to the periodic registration update timer.

NEF 230 may report the received information to third party AS 240. In operation S207, the third party AS 240 recognizes that data transmission is not allowed at an expected time, and may set the scheduled communication time again to a time suitable for UE expected reachability reported from the 5G system.

Fig. 3 is a diagram illustrating operations performed when a UE is already in an unreachable state in a case where an SMF provides scheduling information associated with scheduled data transmission to an AMF according to an embodiment of the present disclosure.

According to the embodiment disclosed in fig. 3, although the third party AS 350 sets the scheduled communication time for the UE, in the case where the UE is in the low power mode and is not reachable through the network (e.g., the MICO mode), the AMF 310 may not enable the UE to be reachable at the scheduled communication time.

For example, if the time corresponding to the scheduled communication time is earlier than the time at which the UE is expected to wake up, the AMF 310 may not confirm whether the UE is awake before the scheduled communication time. Therefore, the AMF 310 cannot ensure the reachability of the UE, and can transfer the time that the UE is expected to be reachable to the SMF 320. SMF 320 may communicate information received from AMF 310 to a third party via a 5G system.

Referring to fig. 3, in operation S301, the SMF 320 has already had a scheduled communication time. This information may be included in the UE context transmitted from UDM 330 or may be information transmitted directly from NEF 340.

In operation S303, the SMF 320 may provide the AMF 310 with information indicating that the predetermined UE needs to be reachable at the scheduled communication time. This operation is based on operation S105 of fig. 1 of the present disclosure. The AMF 310 receiving the message of operation S303 may determine that the UE is already in the MICO mode, and more precisely, in a state of being unreachable through the network due to the low power mode. In addition, the AMF 310 may determine a time at which the UE is reachable based on a periodic registration update timer set for the UE.

If the time corresponding to the scheduled communication time is earlier than the time at which the UE is expected to wake up, the AMF 310 may not acknowledge whether the UE is awake at or before the scheduled communication time. Accordingly, the AMF 310 may not configure the UE based on the scheduled communication time. The AMF 310 may perform operation S307 to report the information to the SMF 320.

The message in operation S307 may include a UE ID, a time when the UE is expected to wake up, or a PDU session ID of the corresponding UE. A time when the UE is expected to be reachable is determined based on a periodic registration update timer. The UE may wake up at a time corresponding to the periodic registration update timer.

The SMF 320 may perform operation S309 in order to report the information to the third party AS 350. SMF 320 may transmit information indicating that the UE is currently unreachable and time information associated with when the UE is expected to be reachable to NEF 340 via UDM 330. Alternatively, SMF 320 may transmit information indicating that the UE is not currently reachable and time information associated with a time when the UE is expected to be reachable directly to NEF 340.

SMF 320 may know the NEF from which information is received in operation S301 and thus may transfer the information to the corresponding NEF. The information in operation S309 may include a UE ID (e.g., an external ID) and a time when the UE is expected to be reachable (which may be determined based on a periodic registration update timer).

NEF 340 may report the received information to the third party AS 350. In operation S311, the third party AS 350 receiving the message of operation S309 may recognize that data transmission is not allowed at an expected time and the scheduled communication time may be set again to a time suitable for UE expected reachability reported from the 5G system.

Fig. 4 is a flowchart illustrating a method in which when a UE and an SMF perform setup of a PDU session for NIDD, the SMF recognizes that NIDD configuration does not exist and allows a corresponding PDU session setup request but performs deactivation according to an embodiment of the present disclosure.

NEF440 and AS 450 may perform a configuration procedure to use data transfer services via NEF, which is background of the embodiments. In this disclosure, this is referred to as a NIDD configuration. The AS 450 and the NEF440 may configure a "data transmission service via NEF" (hereinafter referred to AS "NIDD service") to be used for the UE or the UE group. The UE is indicated by the external ID. The external ID is an identity for the AS 450 to identify the UE, and may identify an internal ID (e.g., SUCI, SUPI, IMSI, etc.) for identifying the UE in the 5G system.

The UE group may be indicated by an external group ID. The external group ID is an identification for the AS 450 to identify a predetermined UE group, and may identify an internal group ID for identifying a UE group or an internal ID of each UE included in a group of a 5G system. Via the NIDD configuration procedure performed between the NEF440 and the AS 450, data transmission characteristics possessed by the corresponding UE or group, such AS a maximum delay, the number of messages transmitted, a scheduled transmission time, a data transmission cycle of the UE, and the like, may be set.

As another background, a procedure for establishing a connection for NIDD service between SMF420 and NEF440 is required. SMF420 needs to identify a NEF to which data obtained from the UE is to be transmitted, and NEF440 needs to identify a SMF to which data obtained from third party AS 450 is to be transmitted, in order to perform data transmission to UE 410.

Accordingly, SMF420 and NEF440 need to perform a connection procedure for NIDD service, which is referred to as "NIDD service activation" for convenience of explanation. As another example, data transfer may be performed via a connection between the UPF and NEF440 for NIDD services. The connection between the UPF and NEF440 may be established through SMF arbitration. Accordingly, in a case where NIDD service is supported via a connection between the UPF and the NEF, SMF420 and NEF440 may perform a connection procedure for NIDD service, SMF420 may configure relevant data routing information for the UPF, and a connection needs to be established between the UPF and NEF 440. NIDD service activation may be a procedure that applies to both cases, that is, a case in which data transfer is performed via a connection between SMF420 and NEF440, and a case in which data transfer is performed via a connection between UPF and NEF 440.

As another background, the UE410 needs to establish a PDU session (hereinafter referred to as NIDD service) of a data transmission service via the NEF440 in order to transmit non-IP data via the NEF 440. UE410 performs a PDU session establishment procedure with SMF420 in order to establish a PDU session. In this example, UE410 may include an identification indicating the PDU session for NIDD service for the procedure. The identification may be a stand-alone identification or a DNN when the corresponding Data Network Name (DNN) has a value indicating NIDD service.

The problems that the present disclosure is intended to solve are as follows. According to conventional methods, after performing the NIDD configuration procedure between the third party AS 450 and the NEF440, the UE410 performs a PDU session setup procedure associated with the corresponding NIDD service of the SMF 420. Then, the SMF420 identifies NIDD configuration information included in subscriber data of the UE410 obtained from the UDM 430, and may perform an NIDD service activation procedure with the NEF indicated by the correspondence information.

If NIDD configuration is not performed in advance between third party AS 450 and NEF440, NIDD configuration information is not present in the subscriber data of UE410, and thus SMF420 may not know the NEF to which a connection for NIDD service is to be established. Accordingly, SMF420 may not allow the PDU session establishment procedure performed by UE410 and may need to reject the corresponding request.

Subsequently, if NIDD configuration is performed between the third party AS 450 and the NEF440, the third party AS 450 may need to send application layer signaling so that the UE410 can perform PDU session setup for NIDD service or may need to perform device triggering using the 3GPP network. Otherwise, the UE410 may not know when the UE410 needs to perform the PDU session setup procedure and may not perform data transmission until the PDU session setup.

However, in order to enable the third party AS 450 to send application layer signaling before the UE410 establishes the PDU session for NIDD, another PDU session different from the PDU session for NIDD may be used. That is, there is a limitation that the UE410 must have another PDU session in addition to the PDU session for NIDD. In addition, in the case of device triggering, the UE410 needs to support SMS in order to support device triggering. In other words, the limitations of current systems require that IoT users be developed only at low cost to support additional functionality.

The present disclosure provides a procedure of successfully performing a NIDD PDU session setup procedure of the UE410 even if NIDD configuration is not previously performed and a connection for NIDD service is established when NIDD configuration is performed. Thus, the 5G system may remove the dependency between the NIDD configuration of UE410 and the NIDD PDU session establishment procedure. In addition, the UE may not need to have another PDU session and may not need to support SMS. The third party AS 450 may not need to support additional application layer operations or device triggering services for the UE410 using NIDD services.

Fig. 4 is a diagram illustrating a procedure in which a UE410 establishes a PDU session for NIDD and operations performed after NIDD configuration is performed, according to an embodiment of the present disclosure.

In operation S401, the UE410 requests a PDU session setup request to the SMF 420. The request message may include an indicator indicating that the NIDD service is to be used, or a DNN value indicating the NIDD service. In addition, an external ID of the UE410 used by the UE410 for NIDD service may be included. SMF420 receiving the request message may determine that UE410 established a PDU session for NIDD service. In operation S403, the SMF420 reports to the UDM 420 that the UE410 is to be served by the SMF420, and subscriber data of the UE410 can be obtained.

In operation S405, the SMF420 identifies that NIDD configuration information does not exist in the subscriber data of the UE410 obtained in operation S403. The PDU session setup request from UE410 is associated with NIDD service. However, NIDD configuration information is not included in the subscriber data of UE410, and thus, SMF420 may determine that NIDD configuration has not been performed. The NIDD configuration information may include at least one of: an address or ID of NEF440 for providing NIDD service to UE410, DNN information for providing NIDD service to UE410, an address of NEF440 associated with the DNN for NIDD service, and an external ID for NIDD service for UE 410. However, SMF420 may identify from the subscriber data of UE410 whether the corresponding UE is a UE allowed to use NIDD service.

The identification method is based on at least one of the following operations. 1. Determining whether the DNN in the subscriber data is the same as the DNN of the NIDD requested by the UE; 2. determining whether an indicator indicating that the UE is allowed to use NIDD services of the corresponding DNN is included; 3. determining whether a network slice used by the UE is a network slice in which NIDD services are available; 4. determining whether an external ID used by the UE for the NIDD service is included in the subscriber data and is the same as a value transmitted by the UE during the PDU session setup in operation S401; or 5. determine whether to allow the UE to use the NIDD service to be included in the subscriber data.

If NIDD configuration information is included in the subscriber data received in operation S403, SMF420 may determine that NIDD configuration has been performed, may transmit a message of operation S417 to the address of NEF440 included in the correspondence information in order to perform NIDD service activation, and may complete a PDU session setup procedure with UE 410.

In operation S407, the SMF420, which determines to provide NIDD service to the UE410 in operation S405, may configure and transmit a PDU session setup accept message to the UE 410. Since NIDD configuration has not been performed, NIDD service activation procedures are not performed between SMF420 and NEF 440.

Accordingly, the message of operation S407 may include an indicator indicating that the PDU session setup is successfully performed but the corresponding PDU session is not activated, that is, data transmission via the corresponding PDU session is not currently available. The UE410 receiving the message may know that the PDU session for the corresponding NIDD is established but not activated and cannot transmit data yet. Accordingly, the UE410 may determine that the service request of the corresponding PDU session is not transmitted until the corresponding PDU session is activated. If the UE410 sends a service request for a corresponding PDU session, the SMF may reject the service request for the corresponding PDU session for the UE410 if NIDD configuration has not been performed and NIDD service activation has not been performed. If UE410 sends a service request corresponding to a PDU session and NIDD configuration and NIDD service activation are performed in advance, SMF420 may accept the service request and activate the PDU session.

As another example of operations S405 and S407, in operation S407, the SMF420 may transmit a PDU session accept to the UE410 via the AMF and the base station. In this example, SMF420 may determine not to transmit an N2 SM message for session establishment (a message between the base station and the SMF) to the base station. That is, the PDU session accept message is transmitted to the UE410, but the base station does not obtain information associated with establishing a radio bearer for the UE410 from the SMF420, and thus, the base station may not establish a radio bearer with the UE 410. Since no radio bearer for the corresponding PDU session with the base station is established, the UE410 may determine that the corresponding PDU session is currently in a deactivated state.

In operation S411, the third-party AS 450 may perform NIDD configuration with the NEF440 for the 5G system in which the UE410 is registered. AS 450 and NEF440 may configure "data transmission service via NEF" to be used for a UE or a UE group. The UE is indicated by the external ID. The external ID is an identity for the AS 450 to identify the UE410, and may also identify an internal ID (e.g., SUCI, SUPI, IMSI, etc.) for identifying the UE410 in a 5G system. The UE group may be indicated by an external group ID. The external group ID is an identification for the AS to identify a predetermined UE group, and in the 5G system, an internal group ID for identifying the UE group or an internal ID of each UE included in the group may also be identified.

In operation S411, the NEF440 and the AS 450 may set data transmission characteristics, e.g., a maximum delay, the number of transmitted messages, a scheduled transmission time, a data transmission period of the UE, etc., possessed by the corresponding UE or group. In operation S411, via a procedure with the UDM 430, the NEF440 may obtain information indicating the SMF420, which SMF420 serves the UE410 associated with the requested NIDD service. In operation S403, the SMF420 registers information indicating that the SMF420 will serve a PDU session for NIDD of the corresponding UE in the UDM 430. Accordingly, the UDM 430 may report to the NEF440 the address or ID of the SMF420 serving the PDU session for the NIDD of the corresponding UE.

NEF440, which obtains the address or ID of SMF420, may transmit the message of operation S413 to the corresponding SMF 420. This is a message used to establish a connection between SMF420 and NEF440 to support NIDD services.

In the message for establishing a connection between SMF420 and NEF440 to support NIDD service according to an embodiment of the present disclosure, an ID for identifying UE410, that is, an external ID, or an ID for identifying a group of UEs 410, that is, an external group ID, may be included. In addition, information required to provide NIDD service to the UE410 may be included. This information may include the ID of NEF440 and a reference ID for identifying a connection with NEF440 for NIDD service. In addition, configuration information for NIDD services may be included. The information may be information associated with a maximum delay required when the corresponding UE or group performs data transmission, a data transmission period of the corresponding UE or group, or a scheduled data transmission time, etc.

When NIDD service is allowed and provided to UE410, the message of operation S413 may operate similar to an event subscription requesting SMF420 to send a report to NEF 440. Accordingly, SMF420 may store information included in the message of operation S413 received from NEF 440.

In operation S415, the SMF420, which determines that NIDD service is available to the UE410, may report to the UE410 that the PDU session for NIDD is activated. This may be performed as follows: SMF420 requests reachability of corresponding UE410 from AMF, the AMF performs paging of UE410, and UE410 transmits a service request in response thereto.

When the UE410 responds via the service request, the AMF reports to the SMF420 that the UE410 has woken up, and the SMF420 may perform a procedure of activating a data path associated with the PDU session of the corresponding UE 410. In this way, an N2 SM message is sent to the base station and the setting of the radio bearer for the UE410 is indicated to the base station.

UE410, being aware of the radio bearer established for the scheduled PDU session, may determine that the data path for the PDU session for NIDD is activated. As another example, SMF420 may report to UE410 that the corresponding PDU session is activated using a PDU session modification procedure in the SM NAS procedure with UE 410. In this instance, a PDU session ID and an indicator indicating that a corresponding PDU session is activated are included in the PDU session modification command message. The UE410 receiving it may determine that the PDU session corresponding to the PDU session ID is activated. The UE410 may identify the PDU session ID and may identify whether the corresponding PDU session is a PDU session for NIDD.

SMF420 activated for the PDU session for NIDD for UE410 may send a message of operation S417 to NEF440, and may complete the NIDD service activation procedure between SMF420 and NEF 440. In this instance, SMF420 may include in the message an external ID of the UE or an external group ID of a group to which the UE belongs, a reference ID for identifying a connection with NEF440 associated with the "data transfer service via NEF" received in operation S413, an ID of NEF440 received in operation S413, and an SMF ID indicating itself. If there is data transmitted by the UE410 via the "data transmission service via NEF", the data may be included in the message of operation S417. NEF440 receiving it may determine that a connection is established with SMF420 transmitting the message of operation S417 "via the data transfer service of NEF" and may recognize the connection by referring to a combination of the ID and the SMF ID.

If NEF440 receives data transmitted from UE410, NEF440 may identify the corresponding data, UE ID or target ID, may determine AS 450 to which the data is directed and which is configured with a "data transmission service via NEF" in operation S417, and may transmit the data to the corresponding AS 450 in operation S419.

Fig. 5 illustrates a PDU session setup operation in which a UE accesses a 5G system and establishes a data connection.

According to an embodiment of the present disclosure, SMF540 may determine whether to apply a small data rate control function, which is one of CIoT functions, to a corresponding UE510 via the procedure of fig. 5. As another example, via the process of fig. 5, SMF540 may receive subscription information for a corresponding UE510 or a policy associated with a corresponding DNN from UDM 560 or PCF 550. Based on this information, SMF540 may determine whether to apply a small data rate control function to the corresponding UE510 or the corresponding DNN.

A detailed description of each operation shown in fig. 5 is as follows.

Operation S501: the UE510 configures a PDU session setup request, which is an SM NAS message, and transmits it to the AMF 530 in order to establish a PDU session. UE510 includes a Data Network Name (DNN) that is desired to be used in the PDU session setup message, and UE510 may set the DNN to a DNN value for CIoT. The DNN information may be used when SMF540 or PCF 550 determines whether the corresponding DNN is a DNN that UE510 is allowed to use for CIoT services. Alternatively, the UE510 may include the radio access technology type (RAT type) currently used by the UE510 in the PDU session setup message. That is, the RAT type may indicate whether the RAT currently accessed by the UE510 is NB-IoT, WB-EUTRAN, NR-IoT (NR modified for IoT), or LTE-M (this is the RAT type used by IoT UEs, although the UE uses WB-EUTRAN, the RAT type may be identified as LTE-M if the UE uses IoT-specific radio technology). The indicator may include a meaning that a function needs to be differently applied to a corresponding PDU session depending on a RAT type. That is, it is determined not to apply small data rate control to the UE accessing the NR. In the same manner, it is determined to apply small data rate control to a UE accessing NB-IoT. In addition, it is determined to apply small data rate control to a UE accessing LTE-M. This information may be used later when SMF540 receives the PDU session setup message sent by UE 510. The RAT type may be included in the PDU session setup message as NAS information or may be included in the PCO of the PDU session setup message.

Operation S503: the AMF 530 may select the SMF540 based on the DNN value or the location of the UE, and may transmit an Nsmf _ pdusesion _ CreateSMContext request message to the selected SMF 540. The AMF 530 may include the PDU session setup request message received from the UE510 in the message. Further, the AMF 530 may include the RAT type currently accessed by the UE510 in the Nsmf _ pdusesion _ CreateSMContext request, according to an embodiment of the present disclosure. The AMF 530 may know the RAT type accessed by the UE510 based on information received from the base station 520. For example, the AMF 530 may identify a tracking area code reported by the base station 520 to which the UE is currently accessing and may identify a RAT type corresponding to the tracking area code. The AMF 530 may determine that the UE510 is a UE using a CIoT function, and may include RAT type information in an Nsmf _ pdusesion _ CreateSMContext request message in order to inform the SMF540 of a RAT type currently accessed by the UE 510. The radio access technology type (RAT type) may indicate whether the RAT that the UE accesses is NB-IoT, WB-EUTRAN, NR-IoT (NR modified for IoT), or LTE-M (this is the RAT type used by the IoT UE, although the UE uses WB-EUTRAN, the RAT type may be identified as LTE-M if the UE uses IoT-specific radio technology).

Operation S505: SMF540 receives the PDU session setup request message received from UE 510. SMF540 may perform a procedure to register SMF540 as a serving SMF in UDM 560 in order to obtain subscription information related to a session associated with UE510, and may perform a procedure to obtain subscription information for session management of UE 510. UDM 560 receiving it may provide subscription information to SMF 540. The subscription information may include information indicating whether the UE510 is able to use a CIoT service, and information associated with whether to apply a CIoT-related function to the UE510, for example, information associated with whether to apply small data rate control or information associated with whether to apply serving PLMN rate control. Alternatively, the subscription information may include information associated with whether to apply CIoT-related functionality to DNNs subscribed to by the UE510, e.g., information associated with whether to apply small data rate control or information associated with whether to apply serving PLMN rate control.

According to a detailed embodiment of the present disclosure, if a RAT type indicating a RAT currently accessed by the UE510 is included in a PCO of a PDU session setup request message or a corresponding message received from the UE510, the SMF540 may store the RAT type in a UE context or may determine a CIoT function to be applied based on the RAT type of the UE.

Alternatively, if the RAT type indicating the current access of the UE510 is included in the message of operation S503 received from the AMF 530, the SMF540 may store the RAT type in the context of the UE510 or may determine a CIoT function to be applied based on the RAT type of the UE 510.

The SMF540 may determine whether to apply the small data rate control function to the UE510 based on the RAT type. In this example, SMF540 may identify subscription information received from UDM 560, and if an indicator indicating whether to apply a CIoT-related function (e.g., small data rate control) is included in the corresponding subscription information, SMF540 may also refer thereto. For example, if UE510 is accessing via the NB IoT RAT, SMF540 may determine to apply the small data rate control function. As another example, if UE510 accesses via WB-ETURAN RAT, SMF540 may identify whether the DNN sent from UE510 is a DNN of CIoT, and may determine to apply the small data rate control function if the DNN is identified as a DNN of CIoT. As another example, if the UE510 makes an access via the WB-ETURAN RAT, the SMF540 may identify information included in the subscription information of the UE510 received from the UDM 560 and information indicating whether the small data rate control function is applied, and may determine that the small data rate control function is applied. As another example, if UE510 is accessing via an NR RAT, SMF540 may determine not to apply a small data rate control function to UE 510. As another example, if the SMF determines that the UE510 is accessed via an NR RAT and identifies information indicating whether a small data rate control function is applied and included in subscription information of the UE510, or determines that DNN requested by the UE510 is DNN of CIoT, the SMF may determine that small data rate control is applied even to the UE510 accessed via an NR RAT. As another example, if UE510 is accessing via an NR-IoT RAT, SMF540 may determine to apply a small data rate control function to UE 510. As another example, if UE510 is accessing via an LTE-M RAT, SMF540 may determine to apply a small data rate control function to UE 510.

Operation S507: SMF540 may identify the PDU session setup request message received from UE510 and may perform an SM policy association setup procedure with the PCF associated with the corresponding DNN. In this example, SMF540 may communicate the DNN requested by UE510 to PCF 550. PCF 550 receiving this information may determine that the corresponding DNN is a DNN for CIoT services and may configure the session-related policy to be communicated to SMF540 to include information indicating whether CIoT-related functionality is to be applied, e.g., whether small data rate control is to be applied.

Operation S509: SMF540 may configure the PCO to be provided to UE 510. PCO is an abbreviation for protocol configuration options. The PCO is a container including additional configuration information required to use a corresponding PDU session, and is information exchanged between the UE510 and the SMF 540. According to an embodiment in operation S505 or S507, the SMF540 may determine whether to apply small data rate control to the UE510, and may set a value for small data rate control for the PCO. The value for small data rate control may be a value set in SMF540, a value obtained by SMF540 from UDM 560, or a value obtained by SMF540 from PCF 550. The information previously configured in SMF540 (pre-configuration) may be set in SMF540 via an OAM system, or may be information pre-configured in SMF540 according to network management by a mobile communication carrier.

The PCO is included in a session management NAS message called "PDU session setup accept" and sent as a NAS message to the UE510 via the AMF 530.

Operation S509: the SMF540 selects the UPF 570 and establishes an N4 session.

Operation S511: the SMF540 may include a PDU session setup accept message to be transmitted to the UE510 and an N2message to be transmitted to the base station 520 in the Namf _ Communication _ N1N2messageTransfer message and may send them to the AMF 530. In the N2message, a PDU session ID, a QoS profile, a QoS flow ID, tunnel information on the UPF 530 side for connecting an N3 tunnel between the UPF 570 and the base station 520, and the like may be included.

The AMF 530 may transmit an ACK associated with the Namf _ Communication _ N1N2messageTransfer to the SMF 540.

Operation S513: AMF 530 may transmit a message received from SMF540 to base station 520. In this message, an N2 SM message received from SMF540 and an N1 SM NAS message received from SMF540 may be included.

Operation S515: the base station 520 may receive the message of operation S513 and may perform an RRC signaling procedure for establishing a data radio bearer with the UE510 according to the QoS information included in the N2 SM message. In addition, the base station 520 may transmit the received NAS message to the UE 510.

The UE510 receiving the PDU session setup accept message transmitted from the SMF540 may complete the PDU session setup procedure. The UE510 may identify PCO information included in the PDU session setup accept message, and may identify information included in the PCO indicating whether to apply small data rate control and a value for applying the small data rate control. The UE510 may apply the small data rate control configured as described above when using the corresponding PDU session.

Operation S517: the base station 520 transmits a response in response to operation S513. An N2 SM message is included in the message. Including the PDU session ID and tunnel information on the base station 520 side for connecting the N3 tunnel with the UPF 570. In addition, information associated with the established QoS flow, etc. may be included.

Operation S519: the AMF 530 receiving the message of operation S517 may transmit the N2 SM message included in the message of S517 to the SMF 540.

Operation S521: the SMF540 may identify the N2 SM message received in operation S519 and may perform an N4 session modification procedure together with the UPF 570. In this example, SMF540 may convey the N3 tunneling information received from base station 520 on the base station 520 side to UPF 570, and may also convey the packet forwarding rules associated therewith. It is also considered that a connection for a tunnel for data transmission or reception is established between the UPF 570 and the base station 520 via operation S521.

Operation S523: the SMF540 sends a response to the AMF 530 in response to operation S519.

The UE510 can perform data transmission or reception via the established PDU session.

Fig. 6 is a diagram illustrating a method of updating information associated with whether to apply small data rate control and a small data rate control value to a UE via a PDU session modification procedure.

The SMF640 may set update information associated with whether to apply the small data rate control and an updated small data rate control value in the PCO information and may transmit it to the UE610 via the procedure of fig. 6.

The PDU session modification procedure may be performed under the following conditions.

-changing access RAT of UE: AMF630, which determines that the RAT accessed by UE610 is changed, may notify SMF640 of the change in RAT type. Accordingly, SMF640, which determines that the RAT type of UE610 is changed, may determine to apply CIoT functionality appropriate for the current RAT of UE 610. For example, if the UE610 to which the small data rate control is applied is changed from NB-IoT to NR RAT, the SMF640 may determine not to apply the small data rate control. As another example, if a UE610 that has been using NR RAT or WB-EUTRAN changes its RAT type to NR-IoT or LTE-M, SMF640 may determine to apply small data rate control. SMF640 may trigger a PDU session modification procedure to provide a continuous PDU session to UE 610. In this example, SMF640 may release the small data rate control related information in the PCO sent to UE610 so that the small data rate control is no longer applied. That is, the small data rate control related information may not be included, or null (null) or 0 may be input to indicate that the small data rate control does not need to be applied. As another example, if a UE610 that has been using a PDU session in an NR RAT changes to an NB-IoT RAT or an LTE-M RAT, SMF640 may determine to apply small data rate control to the corresponding PDU session. SMF640 may trigger a PDU session modification procedure to provide a continuous PDU session to UE 610. In this example, SMF640 may include small data rate control related information in the PCO sent to UE610 in order to apply small data rate control.

In operation S601, the UE610 may configure a PDU session modification request, which is an SM NAS message, in order to change a PDU session since the RAT type of the UE610 is changed. UE610 may communicate a PDU session modification request to AMF 630. The UE610 may include a RAT type in the PDU session modify message indicating the RAT the UE610 accesses. Alternatively, the UE610 may include PCO information in the PDU session modification message and may include information in the PCO indicating the RAT type of the UE 610. For example, the information may include at least one of NB-IoT, WB-EUTRAN, NR-IoT, and LTE-M (this is the type of RAT used by the UE, which is identified as LTE-M despite the UE using WB-EUTRAN if the UE uses IoT-specific radio technology). This information may then be used when SMF640 determines the CIoT functionality to apply based on the RAT type of UE 610. Operation S601 occurs when the UE610 triggers the operation, and the UE610 may not perform operation S601 when the RAT type of the UE610 is changed.

Operation S603: if the AMF630 receives the message of operation S601, the AMF630 may transmit an Nsmf _ pdusesion _ CreateSMContext request message to the SMF 640. The AMF630 may include the PDU session modification request message received from the UE610 in the Nsmf _ pdusesion _ CreateSMContext request. The AMF630 may determine the RAT type of the UE610 by identifying the RAT type transmitted by the base station 620. The AMF630 may include the RAT type of the UE610 in an Nsmf _ pdusesion _ CreateSMContext request message and may transmit it.

SMF640 may identify a RAT type received from AMF630, a RAT type included in a PDU session modification request message received from UE610, or a RAT type in PCO and may determine whether to apply a CIoT-related function (e.g., a small data rate control function) to the corresponding UE 610.

As another example, if the RAT type of the UE610 is changed, the AMF630 may configure an Nsmf _ pdusesion _ CreateSMContext request message and may transmit it to the SMF 640. The AMF630 may determine a RAT type indicating a RAT accessed by the UE610 by identifying a tracking area code transmitted from the base station 620 and a RAT type associated therewith. The AMF630 may include a RAT type indicating a RAT accessed by the UE610 in the Nsmf _ pdusesion _ CreateSMContext request message and may transmit it.

As another example, if the RAT type of UE610 is changed, AMF630 may send an event notification associated with the change in RAT type to SMF 640. The SMF640 receiving it may know that the RAT type of the UE610 is changed and may determine whether to apply a CIoT-related function (e.g., a small data rate control function) to the corresponding RAT type. If it is determined to change the application of the small data rate control function, the SMF640 may proceed to operation S609. S609 may operate even if operation S601 is not performed.

When PCF 650 reports the updated policy information to SMF640, operation S605 is performed.

Operation S607: the SMF640 may receive updates from the UDM 660 related to changes in subscription information, or may give updates to the UDM related to current RAT type information of the UE610 and may receive updates related to subscription information associated therewith.

Operation S609: SMF640, which determines that the RAT type of UE610 is changed, may determine whether to apply a CIoT-related function (e.g., small data rate control) based on the changed RAT type.

In this example, SMF640 may identify subscription information received from UDM 660 and if an indicator indicating whether to apply a CIoT-related function (e.g., small data rate control) is included in the corresponding subscription information, SMF540 may also refer thereto. For example, if UE610 accesses via an NB-IoT RAT, SMF640 may determine to apply a small data rate control function. As another example, if UE610 accesses via WB-ETURAN RAT, SMF640 may identify whether the DNN used by UE610 is a DNN for CIoT, and may determine to apply the small data rate control function if the DNN is identified as a DNN for CIoT. As another example, if the UE610 accesses via the WB-ETURAN RAT, the SMF640 may identify information included in the subscription information of the UE610 received from the UDM and indicating whether to apply the small data rate control function, and may determine to apply the small data rate control function. As another example, if UE610 accesses via an NR RAT, SMF640 may determine not to apply a small data rate control function to the UE. As another example, if the SMF determines that the UE610 accesses via the NR RAT, and identifies information indicating whether to apply the small data rate control function and included in subscription information of the UE610 or determines that the DNN requested by the UE610 is a DNN for CIoT, the SMF may determine to apply the small data rate control to the UE610 accessing via the NR RAT. As another example, if UE610 accesses via an NR-IoT RAT, SMF540 may determine to apply a small data rate control function to UE 610. As another example, if the RAT type indicating the RAT accessed by UE610 is LTE-M, SMF640 may determine to apply a small data rate control function to UE 610.

The SMF640 determining this may configure information associated with whether to apply the small data rate control or a value for applying the small data rate control in the PCO, and may transmit the PCO to the UE 610. In this case, a PDU session modification command as an SM NAS message may be used. The message may be transmitted to the AMF630 via operation S609, and the AMF630 may transmit the message to the UE610 in operations S611 and S613.

Operation S613: the base station may receive the message of operation S611 and may perform an RRC signaling procedure for establishing a data radio bearer with the UE610 according to the QoS information included in the N2 SM message. In addition, the base station 620 may transmit the received NAS message to the UE 610. UE610 may identify the N1 SM NAS message received from SMF640 and may identify the PCO included in the message. The UE610 may identify small data rate control information included in the PCO and may determine whether to apply the small data rate control. If the small data rate control information is not included in the PCO, the UE610 may determine not to apply the small data rate control. Alternatively, if the value set in the PCO for applying the small data rate control is set to null (null) or 0, the UE610 may determine not to apply the small data rate control. The UE610 may configure a PDU session modification complete message indicating that the PDU session modification procedure is completed as an N1 SM NAS message and may transmit it to the SMF 640.

Operation S615: the base station 620 transmits a response in response to operation S613. An N2 SM message is included in the message. The N1 SM NAS message may also be included if the UE610 configures the PDU session modification complete message as an N1 SM NAS message.

Operation S617: the AMF630 receiving the message of operation S615 may transmit the N2 SM message and the N1 SM NAS message included in the message of S615 to the SMF 640.

Operation S619: the SMF640 may identify the N2 SM message received in operation S617, and may perform an N4 session modification procedure with the UPF. In this example, SMF640 may convey base station-side N3 tunneling information received from base station 620 to the UPF and may also convey packet forwarding rules associated therewith. In operation S621, the SMF640 transmits a response to the AMF630 in response to operation S617.

Fig. 7 is a diagram illustrating a structure of a User Equipment (UE) according to an embodiment of the present disclosure.

The UE of fig. 7 is the user equipment shown in fig. 1 to 6. Referring to fig. 7, the UE may include a transceiver 710, a controller 720, and a memory 730. In this disclosure, a controller may be defined as a circuit, an application specific integrated circuit, or at least one processor.

The transceiver 710 may perform transmission or reception of signals with another network entity.

The controller 720 may control the overall operation of the UE according to the embodiment. For example, the controller 720 may control the signal flow such that the operations are performed according to the flowcharts of fig. 1 to 6.

The memory 730 may store at least one piece of information among information transmitted or received via the transceiver 710 and information generated by the controller 720.

Fig. 8 is a diagram illustrating a structure of a network entity according to an embodiment of the present disclosure. The network entity of fig. 6 may be each of the plurality of network entities of fig. 1 through 6. For example, the network entity of FIG. 8 may be an AMF, SMF, UPF, UDM, NEF, or AS/AF.

Referring to fig. 8, the network entity may include a transceiver 810, a controller 820, and a memory 830. In this disclosure, a controller may be defined as a circuit, an application specific integrated circuit, or at least one processor.

The transceiver 810 may perform transmission or reception of signals with another network entity. For example, the transceiver 810 may transmit system information to the UE and may transmit a synchronization signal or a reference signal.

The controller 820 may control the overall operation of the network entity according to the embodiment. For example, the controller 820 may control the signal flow such that the operations are performed according to the flowcharts of fig. 1 to 6.

The memory 830 may store at least one piece of information among information transmitted or received via the transceiver 810 and information generated by the controller 820.

Claims

1. A method of establishing a Protocol Data Unit (PDU) session by a Session Management Function (SMF) in a wireless communication system, the method comprising:

receiving a first message from an Access Management Function (AMF), the first message containing Radio Access Technology (RAT) type information indicating a RAT currently accessed by a User Equipment (UE);

determining whether to apply a small data rate control function to the UE based on the RAT type information; and

transmitting a second message to the AMF, the second message containing information associated with whether to apply a small data rate control function to the UE.

2. The method of claim 1, wherein the small data rate control function is a function in which the UE controls transmission of small data based on a setting value set in a network, and

the setting value includes at least one of the number of data packets that the UE can transmit per hour and the amount of data that the UE can transmit per hour.

3. The method of claim 2, wherein a Protocol Configuration Option (PCO) containing the setting value is configured, the PCO is contained in the second message and sent to the AMF, and the PCO is contained in a PDU session setup accept message and sent to the UE.

4. The method of claim 1, further comprising:

receiving subscription information associated with the UE from a User Data Management (UDM),

wherein the subscription information is considered together with the RAT type information to determine whether to apply the small data rate control function to the UE.

5. The method of claim 1, wherein the RAT type information indicates a RAT that the UE accesses among narrowband IoT (NB-IoT), wideband EUTRAN (WB-EUTRAN), New Radio (NR), new wireless IoT (NR-IoT), and LTE for machine type communication (LTE-M).

6. A method of establishing a Protocol Data Unit (PDU) session by a User Equipment (UE) in a wireless communication system, the method comprising:

transmitting a PDU session establishment request message to an Access Management Function (AMF), the PDU session establishment request message including Radio Access Technology (RAT) type information indicating a RAT to which the UE is currently accessed;

receiving information indicating whether to apply a small data rate control function to the UE and determined based on the RAT type information; and

controlling small data transmission of the UE according to a setting value set in a network based on information indicating whether to apply the small data rate control function to the UE.

7. The method of claim 6, wherein the setting value includes at least one of a number of data packets that the UE can transmit per hour and an amount of data that the UE can transmit per hour.

8. The method of claim 7, further comprising:

receiving a PDU session setup accept message containing a Protocol Configuration Option (PCO) associated with the setting value.

9. The method of claim 6, wherein determining whether to apply the small data rate control function to the UE is based on subscription information associated with the UE and the RAT type information provided from a User Data Management (UDM).

10. The method of claim 6, wherein the RAT type information indicates a RAT that the UE accesses among narrowband IoT (NB-IoT), wideband EUTRAN (WB-EUTRAN), New Radio (NR), new wireless IoT (NR-IoT), and LTE for machine type communication (LTE-M).

11. A Session Management Function (SMF) for establishing a Protocol Data Unit (PDU) session in a wireless communication system, the SMF comprising:

a transceiver; and

a controller configured to: performing control to receive a first message containing Radio Access Technology (RAT) type information indicating a RAT currently accessed by a User Equipment (UE) from an Access Management Function (AMF); determining whether to apply a small data rate control function to the UE based on the RAT type information; and performing control to transmit a second message to the AMF, the second message containing information associated with whether to apply the small data rate control function to the UE.

12. The method of claim 11, wherein the small data rate control function is a function in which the UE controls transmission of small data based on a setting value set in a network, and

wherein the setting value includes at least one of a number of data packets that the UE can transmit per hour and an amount of data that the UE can transmit per hour.

13. The SMF of claim 11, wherein the controller is configured to: performing control to receive subscription information associated with the UE from a User Data Management (UDM); and determining whether to apply the small data rate control function to the UE considering the subscription information together with the RAT type information.

14. A User Equipment (UE) that establishes a Protocol Data Unit (PDU) session in a wireless communication system, the E comprising:

a transceiver; and

a controller configured to: performing control to transmit a PDU session establishment request message containing Radio Access Technology (RAT) type information indicating a RAT currently accessed by the UE to an Access Management Function (AMF); performing control to receive information indicating whether to apply a small data rate control function to the UE and determined based on the RAT type information; and controlling small data transmission of the UE according to a setting value set in the network based on information indicating whether to apply the small data rate control function to the UE.

15. The UE of claim 14, wherein the RAT type information indicates a RAT that the UE accesses among narrowband IoT (NB-IoT), wideband EUTRAN (WB-EUTRAN), New Radio (NR), new wireless IoT (NR-IoT), and LTE for machine type communication (LTE-M).