KR20200099949A - METHOD OF CONTROLLING USER EQUIPMENT FOR CELLULAR IoT SERVICE IN 5G MOBILE COMMUNICATION SYSTEM - Google Patents

Abstract

The present disclosure relates to a communication technique for fusing a 5^th generation (5G) communication system with an Internet of things (IoT) technology to support a higher data transmission rate than that of a 4^th generation (4G) system and a system thereof. The present disclosure can be applied to an intelligent service (for example, smart home, smart building, smart city, smart car or connected car, healthcare, digital education, retail business, security and safety related services, etc.) based on a 5G communication technology and an IoT-related technology. The present disclosure relates to a method for controlling a terminal for a cellular IoT service in a 5G mobile communication system. According to the present disclosure, a control signal processing method in a wireless communication system comprises the steps of: receiving a first control signal transmitted from a base station; processing the first control signal received; and transmitting a second control signal generated based on the processing to the base station.

Description

How to control a terminal for cellular IoT service in a 5G mobile communication system {METHOD OF CONTROLLING USER EQUIPMENT FOR CELLULAR IoT SERVICE IN 5G MOBILE COMMUNICATION SYSTEM}

In describing the embodiments of the present invention in detail, 3GPP uses a radio access network for which 5G network standards are defined, a new RAN (NR), which is a core network, and a packet core (5G system, or 5G Core Network, or NG Core: Next Generation Core). Although it will be the main object, the main subject of the present invention can be applied to other communication systems having a similar technical background with slight modifications without departing from the scope of the present invention, which is skilled in the technical field of the present invention. It will be possible with the judgment of those with technical knowledge.

The CIoT service of the 5G system sends data as a non-access stratum (NAS) message between the terminal and the core network so that the core network transmits it to the external data network, and the data sent from the terminal is transmitted to the external server through the NEF (Network Exposure Function). Can support the function to be delivered.

The 5G system also provides a service for factory automation, which can be called Industrial IoT. Robots and other equipment used in factory automation can communicate using a cellular network, which belongs to a broad category of IoT equipment. Such devices require time-sensitive data communication. For example, status information and command messages should be able to be transmitted to other devices through a network within 10 ms, and may be set to provide status information required at a specific time or to receive status information required at a specific time.

For convenience of description below, some terms and names defined in the 3rd Generation Partnership Project Long Term Evolution (3GPP) standard may be used. However, the present invention is not limited by the terms and names, and can be applied equally to systems conforming to other standards.

Efforts are being made to develop an improved 5G communication system or a pre-5G communication system in order to meet the increasing demand for wireless data traffic after the commercialization of 4G communication systems. For this reason, the 5G communication system or the pre-5G communication system is called a communication system after a 4G network (Beyond 4G Network) or a system after an LTE system (Post LTE). In order to achieve a high data rate, the 5G communication system is being considered for implementation in the ultra-high frequency (mmWave) band (eg, such as the 60 Giga (60 GHz) band). In order to mitigate the path loss of radio waves in the ultra-high frequency band and increase the transmission distance of radio waves, in 5G communication systems, beamforming, massive MIMO, and Full Dimensional MIMO (FD-MIMO) ), array antenna, analog beam-forming, and large scale antenna technologies are being discussed. In addition, in order to improve the network of the system, in 5G communication systems, advanced small cells, advanced small cells, cloud radio access networks (cloud RAN), and ultra-dense networks. , Device to Device communication (D2D), wireless backhaul, moving network, cooperative communication, CoMP (Coordinated Multi-Points), and interference cancellation And other technologies are being developed. In addition, in the 5G system, advanced coding modulation (ACM) methods such as Hybrid FSK and QAM Modulation (FQAM) and SWSC (Sliding Window Superposition Coding), advanced access technologies such as Filter Bank Multi Carrier (FBMC), NOMA (non orthogonal multiple access), and sparse code multiple access (SCMA) have been developed.

On the other hand, the Internet is evolving from a human-centered network in which humans generate and consume information, to an Internet of Things (IoT) network that exchanges and processes information between distributed components such as objects. IoE (Internet of Everything) technology, which combines IoT technology with big data processing technology through connection with cloud servers, is also emerging. In order to implement IoT, technology elements such as sensing technology, wired/wireless communication and network infrastructure, service interface technology, and security technology are required, and recently, a sensor network for connection between objects, machine to machine , M2M), and MTC (Machine Type Communication) technologies are being studied. In the IoT environment, intelligent IT (Internet Technology) services that create new value in human life by collecting and analyzing data generated from connected objects can be provided. IoT is the field of smart home, smart building, smart city, smart car or connected car, smart grid, healthcare, smart home appliance, advanced medical service, etc. through the convergence and combination of existing IT (information technology) technology and various industries. Can be applied to.

Accordingly, various attempts have been made to apply a 5G communication system to an IoT network. For example, technologies such as sensor network, machine to machine (M2M), and MTC (Machine Type Communication) are implemented by techniques such as beamforming, MIMO, and array antenna. There is. As the big data processing technology described above, a cloud radio access network (cloud RAN) is applied as an example of the convergence of 5G technology and IoT technology.

With the recent development of LTE (Long Term Evolution) and LTE-Advanced, there is a need for a method and apparatus for efficiently controlling a terminal for a cellular IoT service in a 5G mobile communication system.

The present invention proposes a method for supporting the following two services in supporting CIoT service in a 5G mobile communication system.

As one of the IoT-related services in 5G mobile communication systems, the 3rd party application server (hereinafter referred to as AS) is when downlink data to be sent to the terminal is scheduled at a specific time, for example, 9 a.m. on Monday or 12 a.m. every day, etc. By providing the schedule information to the mobile communication network, the mobile communication network can prepare for data transmission of the terminal at the corresponding time. The mobile communication network may perform an operation such as adjusting the terminal to be reachable at a time according to the schedule information or securing a resource for data transmission. The present invention proposes a method in which a corresponding terminal in a mobile communication network can maintain a connection state with a mobile communication network at a predetermined data transmission time. This method is particularly effective for IoT terminals that transition from a mobile communication network to a non-reachable state in order to reduce power consumption. A terminal that performs a specific operation to reduce power consumption operates by negotiating with a mobile communication network to turn on the modem and wake up only when there is data to be sent (eg, MICO mode), or to reduce power consumption. Refers to a terminal having a characteristic that cannot paging the terminal in

The present invention for solving the above problem is a control signal processing method in a wireless communication system, the method comprising: receiving a first control signal transmitted from a base station; Processing the received first control signal; And transmitting a second control signal generated based on the processing to the base station.

According to the present invention, the 5G system can support an operation of connecting the terminal to the network at a time according to the schedule in order to enable data transmission to the terminal on a schedule requested from a 3rd party AS providing an application service. Therefore, it is possible to allow the terminal to wake up at a specific time and access the network simply by accessing the 3GPP network without an additional operation of adjusting the operation of the terminal.

1 is a method of negotiating a policy for driving a periodic registration timer with a terminal through a registration procedure and triggering a registration procedure of a terminal after obtaining schedule information for a scheduled data transmission by AMF or SMF according to an embodiment of the present invention Shows.
2 is an operation in which an AMF negotiates capability for a policy driving a periodic registration timer with a terminal through a registration procedure according to an embodiment of the present invention, and a terminal after the AMF or SMF acquires schedule information for a scheduled data transmission How to trigger the registration procedure of

Hereinafter, embodiments of the present invention will be described in detail together with the accompanying drawings. In addition, in describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted. In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary depending on the intention or custom of users or operators. Therefore, the definition should be made based on the contents throughout this specification.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in a variety of different forms, only the present embodiments are intended to complete the disclosure of the present invention, and the general knowledge in the technical field to which the present invention pertains. It is provided to completely inform the scope of the invention to those who have it, and the invention is only defined by the scope of the claims. The same reference numerals refer to the same components throughout the specification.

Description of the entities appearing in the present invention is as follows.

The UE is connected to a radio access network (RAN) to access a device that performs a mobility management function of a 5G core network device. In the present invention, this will be referred to as an Access and Mobility management function (AMF). This may refer to a function or device responsible for both access of the RAN and mobility management of the terminal. SMF is the name of the Network Function that performs the Session Management Function. The AMF is connected to the SMF, and the AMF routes the session-related message to the terminal to the SMF (Session Management Function). The SMF connects with a User Plane Function (UPF) to allocate a user plane resource to be provided to the terminal, and establishes a tunnel for transmitting data between the base station and the UPF. NRF is an abbreviation of Network Repository Function, and it stores information on NFs installed in the mobile communication service provider network and notifies the information. The NRF can be connected to all NFs, and when each NF starts running in the operator's network, it performs a registration procedure with the NRF so that the NRF knows that the NF is running in the network. NEF stands for Network Exposure Function, and plays a role of exposing functions and services inside the mobile operator's network to the outside. Therefore, it is connected to the external application server (AS) to deliver events or information generated from the NF inside the network to the AS, or to deliver the event or information requested by the AS to the internal NF. UDM is an abbreviation for Unified Data Management, with the same role as HSS in 4G networks. This stores the terminal's subscription information or the context that the terminal uses in the network.

As the background technology of the present invention, functions for supporting CIoT service are as follows.

Scheduled Downlink Data Communication Service: The 5G mobile communication network may receive schedule information on a scheduled downlink data transmission time for a specific terminal or group from a 3rd party AS. 3 ^rd party AS LA also can mean an Application Server that there is only 5G mobile communication network components. For example, to support data transmission using the 5G mobile communication system in Industrial IoT, Application Server to be run to the IoT Industrial Services it may be considered as a 3 ^rd party AS in position 5G mobile communication system. As another example, a service provider providing an IoT service may issue commands to IoT terminals at regular times, or may designate a Scheduled Communication Time to proceed with Software Update at a specific time. The 3rd party AS is the time or schedule information that the terminal should be available to the 3GPP network for data reception through the “Expected UE Behavior” provisioning API through NEF (ie Time to do it). This schedule information may include a plurality of schedule information. For example, it is possible to provide multiple schedules, such as 9 o'clock on every Monday, 0 o'clock every day, or 10 hours after the current time, 20 minutes after the current time, and so on.

Receiving this, the terminal uses the power saving state (meaning that the terminal is not reachable from the network to reduce power consumption, that is, the terminal does not perform network connection-related operations such as not monitoring the paging channel). When you want to, you can set it so that you can find the terminal in the network (reachable) at the scheduled communication time. For example, by comparing the scheduled communication time and the time when the terminal periodically notifies the network of reachability (e.g., Periodic Registration Request Timer), the next periodic registration request time of the terminal can be set according to the Scheduled Communicataion time. As another example, if the scheduled communication time exists before the next periodic registration request time of the terminal, the power saving function for the terminal is not allowed, so that the terminal can be reached at that time.

First embodiment: Fig. 1

1 is a method for triggering a registration procedure of a terminal after acquiring schedule information for a scheduled data transmission by an AMF or SMF according to an embodiment of the present invention, and negotiating a policy for driving a periodic registration timer with the terminal through the registration procedure Shows.

In order to reduce power consumption, the terminal stops monitoring the paging channel (e.g., MICO mode, PSM in 4G system), or performs an operation such as monitoring the paging channel only at a specific time interval (e.g. IDLE mode DRX). I can. To this end, the terminal must negotiate with the AMF, and negotiate through the registration procedure. In the present invention, an example is given that the terminal negotiates to use the MICO mode. However, this may comprehensively mean other functions that the terminal must negotiate with the AMF to reduce power consumption. For example, there may be 5G Power Saving Mode, 5G DRX, and 5G Extended DRX. In the present invention, for convenience, it will be described in MICO mode. The MICO mode refers to a mode in which when the terminal goes to the IDLE mode, all paging channels are no longer monitored and the terminal cannot be found in the 5G network, that is, it moves to an Unreachable state. The terminal reconnects to the 5G network when it needs to send data or signaling, or after the periodic Registration Request Timer set by the network expires. Therefore, the network cannot wake up the terminal until the Registration Request procedure that the terminal performs at a set periodic time occurs.

According to an embodiment of the present invention, the following information is proposed. Periodic Registration Request Time represents a time value at which the terminal should periodically perform a registration request. This is allocated by the AMF to the terminal. Periodic Registration Request Timer means a timer that operates according to the Periodic Registration Request Time value, and is driven by the terminal and the AMF, respectively. In addition, the present invention proposes a policy for the periodic registration request timer operation of the terminal. (For convenience, it is referred to as the Periodic Registration Request Timer Policy.) This means an indicator that when the terminal operates the Periodic Registration Request Timer, it does not stop the Periodic Registration Request Timer when it transitions from CM-IDLE to CM-Connected. Alternatively, the Periodic Registration Timer running policy starts the corresponding Timer from the moment the terminal is assigned the Periodic Registration Request Timer, and when the transition from CM-Connected to CM-IDLE or from CM-Connected to CM-IDLE, the Periodic Registration Request Timer is set. It may mean an indicator to keep running without stopping. In addition, it indicates whether the periodic registration timer running policy is a one-time policy (i.e., a policy to apply and release once) or a policy that continues to be applied (a policy that maintains the Periodic Registration Request Timer Policy until AMF issues a new policy). May contain indicators. If an indicator to continue operation without stopping the Periodic Registration Request Timer is included as in the Periodic Registration Timer running policy, the terminal continues to operate the corresponding timer when the CM-IDLE transitions to CM-Connected, and even while maintaining the Connected state. Starts the timer and keeps running until the timer expires. In addition, the terminal starts the corresponding Timer from the moment the Periodic Registration Request Timer is allocated with the above indicator, and does not stop the Periodic Registration Request Timer when the transition from CM-Connected to CM-IDLE or from CM-Connected to CM-IDLE. It will continue to operate without. If the periodic registration timer running policy includes an indicator that is a one-time policy, the terminal releases the application of the policy after the periodic registration request timer expires. In other words, the periodic registration timer operation is performed as a general operation (timer stops when transitioning from CM-IDLE to CM-Connected, and restarts from the initial value of the timer when transitioning from CM-Connected to CM-Idle).

The 3rd party application server or AS sets the scheduled communication time in the 5G network. In this case, the AS directly sends a message to the UDM or AMF and transmits it, or transmits information to the UDM through NEF, and the UDM may transmit the information to the AMF or SMF as the terminal context. The AS can configure and deliver the Scheduled Communication time in multiple schedules. For example, multiple schedule information such as 0 o'clock every day, 12:30 every day, or 20 minutes after the present, or an absolute time value representing a time later than the present (e.g. UTC 20:00 July 10, 2018) Can be delivered to 5G networks.

In the present invention, according to Step 1 and Step 2-1, it is assumed that the Scheduled Communication Time is stored in the context of the UE in the UDM, and thus the AMF or SMF acquires it. AF can provide corresponding information through NEF, NEF delivers it to UDM, and UDM can classify and store the corresponding information in the Session Management Context of the terminal. Alternatively, according to Step 1 and Step 2-1, the NEF directly transmits the Scheduled Communication Time for a specific terminal to the AMF or SMF, so that the AMF or SMF can obtain the corresponding value. Since the Scheduled Communication Time is provided to the UDM for a specific terminal indicated by the External ID or External Group ID from the 3rd party, the UDM can store the Scheduled Communication Time value for each External ID or External Group ID of the terminal in the SM context. This is because the terminal may have multiple External IDs or External Group IDs. Alternatively, the scheduled communication time may be provided to UDM as a value for a specific data network name (DNN) for a specific terminal indicated by an external ID or external group ID from a 3rd party. In this case, the UDM may store a Scheduled Communication Time value in the SM context according to the DNN value for each External ID or External Group ID of the terminal. This is to support the case where the terminal has multiple External IDs or External Group IDs, or when subscriber information is configured so that the terminal can use multiple DNNs for NIDD service. That is, the Scheduled Communication Time is set in UDM subscriber information for each terminal, and several may be set for each External ID or External Group ID, or for each External ID/External Group ID and DNN.

Step 2-2 is an operation subsequent to step 2-1, that is, when the SMF obtains information about the scheduled communication time from the UDM as the SM context for the terminal or the SMF obtains it from the NEF. The SMF can determine when downlink data transmission to the corresponding terminal occurs by looking at the Scheduled Communication Time. Since the SMF needs to be reachable to the 5G network at the corresponding time, the SMF can send a message requesting the reachability of the terminal to the AMF in charge of mobility management of the terminal. This is one of the APIs provided by AMF and may be different from the name for step 2-2 in the drawing, but if the SMF is a message that provides the AMF with the scheduled communication time of a specific terminal, it can be said to correspond to the message proposed in the present invention. have. For example, it can be delivered using an API provided by SMF such as Nsmf_PDU Session Update SM Context. SMF is the ID of the terminal in step 2-2 (an ID that can identify the terminal in the AMF, for example, SUCI (Subscription Concealed Identifier) or SUPI (Subscription Permanent Identifier, old IMSI may correspond to this), or External ID. ), includes a Scheduled Communication Time acquired from step 2-1, and may include a PDU session ID indicating a corresponding PDU session. The reason for including the PDU Session ID is that when the UE uses data communication with multiple PDU Sessions, the UE sends a Service Request at the Scheduled Communication Time, and it is possible to determine which PDU Session to activate when awakening. In addition, when the terminal uses data communication with multiple PDU sessions, it is for the AMF to distinguish which PDU session is the scheduled communication time. When the AMF can receive multiple SMFs or multiple Scheduled Communication Time values from one SMF, it can identify the Scheduled Communication Time values for each PDU session by looking at the PDU Session ID included in Message 2-2.

The message according to step 2-2 or the AMF that knows the scheduled communication time for the terminal through step 1 stores this in the context of the terminal. Also, a Periodic Registration Timer value can be assigned based on this. The AMF may determine to apply the periodic registration timer running policy to the terminal so that the terminal can wake up and access the network at the scheduled communication time. That is, when the terminal transitions from CM-IDLE to CM-Connected, the Periodic Registration Timer is instructed not to stop, so that the Periodic Registration Timer continues to operate even when the terminal is connected, and the Periodic Registration Timer expires later in the CM-IDLE state. When it is done, it can connect to the network by performing the registration procedure so that the terminal can attach to the network when scheduled communication occurs.

The AMF performs step 3 to deliver the Periodic Registration Time value and the Periodic Registration Timer running policy according to the Scheduled Communication Time, or when the terminal leaves the Reachable state for a specific time from the network to reduce power consumption through the registration procedure. When an operation is requested, for example, when a MICO mode is requested through a registration procedure, it can be transmitted to the terminal.

According to step 1 or step 2-2, the AMF knows that the scheduled communication time has been set to the terminal, and accordingly may determine to adjust the periodic registration request timer value of the terminal. In addition, it is possible to determine the policy for the periodic registration request timer operation of the terminal. For example, if the Scheduled Communication Time for the terminal is a one-time time, that is, indicates a specific time (UTC 12:00, 2019-02-12), the Periodic Registration Request Timer Policy may be determined as a one-time policy. As another example, when the Scheduled Communication Time for the terminal is a regular time, that is, for example, every Monday at 9 am, or every day at 12 noon, it may be decided to apply the Periodic Registration Request Timer Policy as a policy that continues to apply. The AMF may set the indicator accordingly, which may be delivered to the terminal during the registration procedure.

The AMF may perform the UE Configuration Update procedure according to Step 3 to make the UE wake up at the Scheduled Communication Time, to transmit the Periodic Registration Timer to the UE, or to perform the Registration procedure. This is to deliver the periodic registration timer value and the periodic registration timer running policy according to the scheduled communication time to the terminal. The AMF may include a Periodic Registration Timer value determined through the above procedure and a Periodic registration timer running policy in the UE Configuration Update Command message according to step 3. The periodic registration timer running policy may mean an indicator that the Periodic Registration Timer should continue to operate regardless of the CM-IDLE/CM-Connected transition. Alternatively, the Periodic Registration Timer running policy starts the corresponding Timer from the moment the terminal is assigned the Periodic Registration Request Timer, and when the transition from CM-Connected to CM-IDLE or from CM-Connected to CM-IDLE, the Periodic Registration Request Timer is set. It may mean an indicator to keep running without stopping. In addition, it may include an indicator indicating whether the corresponding periodic registration timer running policy is one-time or should be maintained continuously. The UE transmits a response message to the UE Configuration Update Command sent by the AMF, and at this time, it may acknowledge that the transmitted information has been well applied.

Alternatively, the AMF may only perform an operation of triggering the UE to perform a Registration Request, instead of including the Periodic Registration Timer and Periodic Registration Timer running policy information as described above in the UE Configuration Update Command message. Therefore, the AMF can send an indication that the registration procedure needs to be performed to the UE by including it in the UE Configuration Update Command message. In this case, the AMF may include an indicator that the terminal can use the MICO mode. The terminal transmits a response message to the UE Configuration Update Command sent by the AMF.

According to step 4, the terminal sends a Registration Request message including an indicator indicating that it will use the MICO mode. Step 4 may be performed by the operation according to step 3. That is, when the AMF informs the terminal that the registration procedure needs to be performed through the UE Configuration Update Command message in step 3, the registration procedure may be performed through step 4. Alternatively, step 4 may be performed because the terminal needs negotiation with the AMF to activate the MICO mode for power consumption reduction operation. In addition, it may be a registration procedure according to the mobility of the terminal, or a registration procedure performed at a periodic time. In addition, it may be a registration procedure performed by the terminal to synchronize time with the network. In other conditions, it may include both the terminal performing the AMF and registration procedures.

According to step 5, the AMF determines whether or not to allow the MICO mode to the terminal. If the scheduled communication time value for the terminal arrives soon, the AMF may not allow the MICO mode for the terminal so that the terminal does not enter the MICO mode and remains in a reachable state. If the Scheduled Communication Time value for the terminal is sufficient time after the terminal enters the MICO mode, the AMF may allow the MICO mode so that the terminal can enter the MICO mode and achieve the purpose of reducing power consumption.

According to step 6, the AMF may set a periodic registration timer value that the corresponding terminal should drive to the terminal that will allow the MICO mode. This is set based on the Scheduled Communication Time value, and the AMF can set a value indicating a time slightly earlier than the Scheduled Communication Time. This is to consider a delay that may occur when the terminal accesses the network. In addition, the AMF may set the Periodic Registration Timer Running Policy to allow the terminal to wake up at the Scheduled Communication Time and access the network. This means an indicator to continue operation without stopping Periodic Registration Request Timer when transitioning from CM-IDLE to CM-Connected. In addition, it indicates whether the periodic registration timer running policy is a one-time policy (i.e., a policy to apply and release once) or a policy that continues to be applied (a policy that maintains the Periodic Registration Request Timer Policy until AMF issues a new policy). May contain indicators.

Through step 7, the AMF sends the periodic registration timer value and the periodic registration timer running policy determined in step 6 together with an indicator that the MICO mode is allowed to the terminal. The terminal receiving this may see the Periodic Registration Timer running policy among the received information and determine that the Periodic Registration Request Timer is to be continuously operated without stopping the Periodic Registration Request Timer when CM-Connected transitions from CM-IDLE. Accordingly, the terminal may drive the Periodic Registration Timer according to the received Periodic Registration Timer value after the registration procedure is finished (ie, after step 8 of sending the Registration Complete message to the AMF). Alternatively, the terminal may receive the Registration Accept, check the Periodic Registration Request Timer included therein, and run the Timer immediately after confirming that the Timer is applied to the Periodic Registration Timer Running Policy. The terminal continues to operate the timer even when the CM-IDLE transitions to CM-Connected, operates the timer even while maintaining the connected state, and continues to operate until the timer expires. If the periodic registration timer running policy includes an indicator that is a one-time policy, the terminal releases the application of the policy after the periodic registration request timer expires. In other words, the periodic registration timer operation is performed as a general operation (timer stops when transitioning from CM-IDLE to CM-Connected, and restarts from the initial value of the timer when transitioning from CM-Connected to CM-Idle).

Through step 8, the terminal may notify the completion of the registration procedure. According to an embodiment of the present invention, the terminal may send an acknowledgment that it will apply the Periodic Registration Timer Running Policy received in step 7 to the AMF through the Registration Complete message. Upon receiving this, the AMF determines that the UE will apply the Periodic Registration Timer Running Policy, and accordingly drives the Periodic Registration Timer at the AMF end. Since the terminal acknowledges that it applies the Periodic Registration Timer Running Policy, the AMF continues to operate the corresponding timer even when the terminal's connection state transitions from CM-IDLE to CM-Connected, as well as the terminal operation. Is operated, and continues to operate until Timer expires. AMF can perform this Timer immediately after receiving the Registration Complete message. The Periodic Registration Timer value driven by the AMF end may have a slightly larger value than the value allocated to the UE. For example, it can have a value of 5 minutes or so. This is a situation in which a time delay may occur due to a failure such as a radio situation when the UE performs the Periodic Registration procedure, and the AMF cannot receive the Registration Request message from the UE even after the Periodic Registration Timer expires during the time due to this failure. At this time, the AMF is to prevent the terminal from determining that implicit deletion has been performed. As AMF drives a timer with a slightly larger value, even if there is a delay in performing the registration procedure due to a failure in the wireless situation, the terminal can correctly perform the registration procedure without determining that the terminal is implicit detached.

According to an embodiment of the present invention, the terminal may not send an acknowledgment to the AMF that it will apply the Periodic Registration Timer Running Policy received in step 7 through the Registration Complete message. That is, if the terminal does not support the Periodic Registration Timer Running Policy or decides not to use it, the Registration Complete message may not be transmitted to the AMF, and even if transmitted, the ACK indicating that the Periodic Registration Timer Running Policy has been applied may not be included. Upon receiving this, the AMF may determine that the terminal does not support or does not use the Periodic Registration Timer Running Policy. Accordingly, AMF drives the Periodic Registration Timer according to the general operation. Since the terminal also does not support or apply the Periodic Registration Timer Running Policy, it drives the Periodic Reigstration Timer according to the general operation.

After completing the registration procedure, the terminal, which has been permitted to operate in the MICO mode, transitions to the IDLE state and operates in the MICO mode. In addition, when the terminal determines to apply the Periodic Registration Timer Running Policy, the terminal drives the Periodic Registration Timer accordingly. While the terminal is in MICO mode, the network cannot paging the terminal. When the terminal operates a long DRX cycle other than the MICO mode, the network cannot paging the terminal while the terminal is in the DRX sleep cycle. However, if there is data or signaling to be sent to the network, the terminal can wake up and communicate with the network at any time according to step 9. If the AMF has a newly configured Scheduled Communication Time value, the AMF can perform an operation of updating the Periodic Registration Timer and Periodic Registration Timer Running Policy to the terminal accordingly through the UE Configuration Update procedure (same as step 3).

According to an embodiment of the present invention, as in step 10a, when the set Periodic Registration Timer expires, the terminal wakes up and connects to the network, and performs a Registration Request operation to transition to the Connected state. Upon receiving this, the AMF transitions the state of the terminal to Connected. According to an embodiment of the present invention, the AMF notifies the SMF for the PDU session or DNN for which the Scheduled Communication Time is set, and notifies the UE's reachability, and activates the user plane of the UE or the data path of the UE to transmit scheduled downlink data. You can let it go.

In step 10a, the terminal may be in a CM-Connected state. That is, the periodic registration timer may expire while the terminal accesses the network to transmit and receive data for the data transmission operation. In this case, since the terminal is already connected to the network, there is no need to perform the registration procedure when the timer expires for network access. According to an embodiment of the present invention, the terminal may perform the following operations. First, if the Periodic Registration Timer Running Policy is set and the Periodic Registration Timer is driven accordingly, the terminal may decide not to perform the Periodic Registration procedure when the Timer expires in the Connected state based on this criterion. Since the Timer has expired, the UE does not restart the Periodic Registration Timer until it transitions to CM-IDLE. After completing data transmission and reception, the terminal switches to CM-IDLE and then drives the Periodic Registration Timer again. Alternatively, if the terminal was in the CM-Connected state at the time the Timer expired, the Timer may be restarted immediately by applying the preset Periodic Registration Timer and the Periodic Registration Timer Running Policy for it without performing the Periodic Registration procedure. In other words, without waiting for the transition to CM-IDLE, when the timer expires in the connected state, it restarts immediately and the Periodic Registration Timer Running Policy can be applied until the next timer expires. At this time, if the UE receives an indicator indicating whether the corresponding policy is one-time or continuous in the Periodic Registration Timer Running Policy from the AMF, the UE may perform the following operation according to this indicator. If the Periodic Registration Timer Running Policy is one-time, the terminal releases the Periodic Registration Timer Running Policy after the Periodic Registration Timer expires in the Connected state. In other words, Periodic Registration Timer Running Policy is no longer applied. If the Periodic Registration Timer Running Policy is continuously applied, the UE continues to maintain the Periodic Registration Timer Running Policy after the Periodic Registration Timer expires in the Connected state. Accordingly, after the Timer expires in the CM-Connected state, the Timer is restarted again, and the Timer can be driven according to the Periodic Registration Timer Running Policy. Second, the terminal can perform the periodic registration procedure in the connected state. Although the timer expires and the terminal is in the connected state, if the terminal has set the Periodic Registration Timer Running Policy and has started the Periodic Registration Timer accordingly, it is decided to perform the periodic registration procedure when the timer expires in the connected state based on this criterion. I can. Through this procedure, it can be confirmed that the terminal reassigns the Periodic Registration Timer, receives a new Periodic Registration Timer Running Policy, or no longer applies the Periodic Registration Timer Running Policy. If the AMF does not include the Periodic Registration Timer Running Policy in the Registration Accept message, the UE may determine that the Periodic Registration Timer Running Policy is no longer applied.

When the periodic registration timer running at the AMF end for the terminal expires, if the terminal is in a connected state, and if the periodic registration timer running policy has been applied, the AMF according to an embodiment of the present invention follows step 3 UE Configuration Update procedure can be performed. This is to update the periodic registration timer value and periodic registration timer running policy information according to the scheduled communication time to the terminal. If the AMF determines that the Scheduled Communication Time is no longer valid, that is, there is no scheduled communication time set, or that it is no longer necessary to apply the Schedueld Communication Time, the AMF informs the UE that the Periodic Registration Timer Running Policy has been released through the UE Configuration Update procedure. Can be judged. As another example, if there is a valid Scheduled Communication Time set after the current time, the AMF may determine to set the Periodic Registration Timer according to the corresponding Scheduled Communication Time and also apply the Periodic Registration Timer Running Policy. The AMF may include a Periodic Registration Timer value determined through the above procedure and a Periodic registration timer running policy in the UE Configuration Update Command message. The periodic registration timer running policy may mean an indicator that the Periodic Registration Timer should continue to operate regardless of the CM-IDLE/CM-Connected transition. In addition, it may include an indicator indicating whether the corresponding periodic registration timer running policy is one-time or should be maintained continuously. The UE transmits a response message to the UE Configuration Update Command sent by the AMF, and at this time, it may acknowledge that the transmitted information has been well applied. When it is determined that the AMF no longer applies the Periodic Registration Timer Running Policy, the UE Configuration Update Command message may include an identifier indicating termination of the Periodic Registration Timer Running Policy. After the AMF determines that the terminal has applied the Periodic Registration Timer Running Policy, the UE Configuration Update Command message sent to the corresponding terminal may include an identifier indicating termination of the Periodic Registration Timer Running Policy. The UE transmits a response message to the UE Configuration Update Command sent by the AMF, and at this time, it may acknowledge that the transmitted information has been well applied.

Alternatively, the AMF may only perform an operation of triggering the UE to perform a Registration Request, instead of including the Periodic Registration Timer and Periodic Registration Timer running policy information as described above in the UE Configuration Update Command message. Therefore, the AMF can send an indication that the registration procedure needs to be performed to the UE by including it in the UE Configuration Update Command message. In this case, the AMF may include an indicator that the terminal can use the MICO mode. The terminal transmits a response message to the UE Configuration Update Command sent by the AMF. After that, the terminal performs the registration procedure as in step 4.

Step 10b indicates that Downlink Data has occurred as scheduled at the Scheduled Communication Time. After receiving the downlink data from the data network, the UPF notifies the SMF and activates the data path for transmitting the data to the terminal. This process can follow the NW-initiated Service Request. According to the NW-initiated Service Requset, the network paging the terminal, and the awakened terminal sends a Service request, and the terminal transitions to the connected state.

The terminal may send a Registration Request message to the AMF as in step 11 according to the determination operation according to step 10a. Upon receiving this, the AMF can maintain the connection of the terminal for a certain period of time until a downlink data notification for the terminal is received. This is because if the terminal returns to the IDLE state, it may become Unreachable again. If downlink data for the terminal arrives while the connection of the terminal is maintained, and the SMF informs the AMF that the data path for the terminal should be activated, the AMF can perform a procedure for activating the corresponding data path. As another example, in step 11, the terminal may include information on the PDU session to activate the data path in “PDU Session to be Activated” along with the Registration Request. This is because the terminal applies the Periodic Registration Timer Running Policy, so it is determined that there will be scheduled communication and included. Therefore, it is to activate the Data Path by requesting to activate the corresponding PDU session. This has the effect that the SMF can omit the procedure of notifying the AMF that the Donwlink Data has arrived. Upon receiving this, the AMF may trigger the activation of the Data Path to the SMF for the corresponding PDU Session. After the data path for transmitting data to the terminal is activated by the above three operations, data is transmitted to the terminal according to step 12.

Second embodiment: Fig. 2

2 is an operation in which an AMF negotiates capability for a policy driving a periodic registration timer with a terminal through a registration procedure according to an embodiment of the present invention, and a terminal after the AMF or SMF acquires schedule information for scheduled data transmission. How to trigger the registration procedure of

In order to reduce power consumption, the terminal stops monitoring the paging channel (e.g., MICO mode, PSM in 4G system), or performs an operation such as monitoring the paging channel only at a specific time interval (e.g. IDLE mode DRX). I can. To this end, the terminal must negotiate with the AMF, and negotiate through the registration procedure. In the present invention, an example is given that the terminal negotiates to use the MICO mode. However, this may comprehensively mean other functions that the terminal must negotiate with the AMF to reduce power consumption. For example, there may be 5G Power Saving Mode, 5G DRX, and 5G Extended DRX. In the present invention, for convenience, it will be described in MICO mode. The MICO mode refers to a mode in which when the terminal goes to the IDLE mode, all paging channels are no longer monitored and the terminal cannot be found in the 5G network, that is, it moves to an Unreachable state. The terminal reconnects to the 5G network when it needs to send data or signaling, or after the periodic Registration Request Timer set by the network expires. Therefore, the network cannot wake up the terminal until the Registration Request procedure that the terminal performs at a set periodic time occurs.

According to an embodiment of the present invention, the following information is proposed. Periodic Registration Request Time represents a time value at which the terminal should periodically perform a registration request. This is allocated by the AMF to the terminal. Periodic Registration Request Timer means a timer that operates according to the Periodic Registration Request Time value, and is driven by the terminal and the AMF, respectively. In addition, the present invention proposes a policy for the periodic registration request timer operation of the terminal. (For convenience, it is referred to as the Periodic Registration Request Timer Policy.) This means an indicator that when the terminal operates the Periodic Registration Request Timer, it does not stop the Periodic Registration Request Timer when it transitions from CM-IDLE to CM-Connected. In addition, it indicates whether the periodic registration timer running policy is a one-time policy (i.e., a policy to apply and release once) or a policy that continues to be applied (a policy that maintains the Periodic Registration Request Timer Policy until AMF issues a new policy). May contain indicators. If the periodic registration request timer is included in the periodic registration timer running policy to continue operation without stopping the periodic registration request timer when the CM-IDLE transitions to CM-Connected through the periodic registration timer running policy, the terminal continues to operate the corresponding timer when the CM-IDLE transitions to CM-Connected. It runs the timer even while maintaining the connected state, and continues to run until the timer expires. Or, the terminal starts the corresponding Timer from the moment it is assigned the Periodic Registration Request Timer, and when the transition from CM-Connected to CM-IDLE or from CM-Connected to CM-IDLE, keeps the Periodic Registration Request Timer running without stopping. I can. If the periodic registration timer running policy includes an indicator that is a one-time policy, the terminal releases the application of the policy after the periodic registration request timer expires. In other words, the periodic registration timer operation is performed as a general operation (timer stops when transitioning from CM-IDLE to CM-Connected, and restarts from the initial value of the timer when transitioning from CM-Connected to CM-Idle).

The 3rd party application server or AS sets the scheduled communication time in the 5G network. In this case, the AS directly sends a message to the UDM or AMF and transmits it, or transmits information to the UDM through NEF, and the UDM may transmit the information to the AMF or SMF as the terminal context. The AS can configure and deliver the Scheduled Communication time in multiple schedules. For example, multiple schedule information such as 0 o'clock every day, 12:30 every day, or 20 minutes after the present, or an absolute time value representing a time later than the present (e.g. UTC 20:00 July 10, 2018) Can be delivered to 5G networks.

According to step 1, the terminal transmits the Registration Request message including an indicator indicating that it will use the MICO mode. In addition, according to an embodiment of the present invention, the terminal may transmit including an indicator indicating whether it can support the Periodic Registration Timer Running Policy. Through an indicator, the terminal can support the Periodic Registration Timer Running Policy, that is, whether it can support the function of continuing to run the Periodic Registration Timer while transitioning from CM-IDLE to CM-Connected and maintaining the CM-Connected state. Show. If the terminal includes the indicator in the message, the AMF receiving the indicator may determine that the terminal supports the function. Similarly, if the terminal does not include an indicator in the message, the AMF receiving the Registration Request message may determine that the terminal does not support the corresponding function. Step 1 may be performed by the operation according to step 13. That is, when the AMF informs the terminal that it is necessary to perform the registration procedure through the UE Configuration Update Command message in step 13, the registration procedure may be performed through step 1. Alternatively, step 1 may be performed because the terminal needs negotiation with the AMF to activate the MICO mode for power consumption reduction operation. In addition, it may be a registration procedure according to the mobility of the terminal, or a registration procedure performed at a periodic time. In addition, it may be a registration procedure performed by the terminal to synchronize time with the network. In other conditions, it may include both the terminal performing the AMF and registration procedures.

According to step 2, the AMF determines whether to allow the MICO mode to the terminal. If the scheduled communication time value for the terminal arrives soon, the AMF may not allow the MICO mode for the terminal so that the terminal does not enter the MICO mode and remains in a reachable state. If the Scheduled Communication Time value for the terminal is sufficient time after the terminal enters the MICO mode, the AMF may allow the MICO mode so that the terminal can enter the MICO mode and achieve the purpose of reducing power consumption.

The AMF determined to allow the MICO mode to the terminal through step 2 may set a Periodic Registration Timer value that the terminal should drive according to the scheduled communication time set for the terminal. In addition, the Periodic Registration Timer Running Policy can be determined. At this time, according to an embodiment of the present invention, the AMF determines whether to apply the Periodic Registration Timer Running Policy to the UE by looking at an indicator indicating the capability of the Periodic Registration Timer Running Policy in the message of Step 1 received from the UE. That is, if the terminal includes the indicator in the message, the AMF receiving the indicator may determine that the terminal supports the function. Similarly, if the terminal does not include an indicator in the message, the AMF receiving the Registration Request message may determine that the terminal does not support the corresponding function. Alternatively, if the indicator itself indicates that there is capability for the Periodic Registration Timer Running Policy, it may be determined that the terminal supports the corresponding function. Alternatively, if it indicates that there is no capability for the Periodic Registration Timer Running Policy, it may be determined that the terminal does not use the corresponding function. AMF is determined based on the value of Scheduled Communication Time when setting the Periodic Registration Timer, and AMF can set a value indicating a time slightly earlier than the Scheduled Communication Time. This is to consider a delay that may occur when the terminal accesses the network. In addition, the AMF may set the Periodic Registration Timer Running Policy to allow the terminal to wake up at the Scheduled Communication Time and access the network. This means an indicator to continue operation without stopping Periodic Registration Request Timer when transitioning from CM-IDLE to CM-Connected. Or, as soon as this indicator receives the Periodic Registration Timer (i.e., after receiving the Registration Accept message and checking the Periodic Registration Timer and Periodic Registration Timer Running Policy information in it), it is immediately driven, and the transition from CM-Connected to CM-IDLE or CM When transitioning from -Connected to CM-IDLE, it can mean an indicator to keep the Periodic Registration Request Timer running without stopping. In addition, it indicates whether the periodic registration timer running policy is a one-time policy (i.e., a policy to apply and release once) or a policy that continues to be applied (a policy that maintains the Periodic Registration Request Timer Policy until AMF issues a new policy). May contain indicators.

Through step 4, the AMF transmits the periodic registration timer value and the periodic registration timer running policy determined in step 3 to the terminal along with an indication that the MICO mode is allowed. The terminal receiving this may see the Periodic Registration Timer running policy among the received information and determine that the Periodic Registration Request Timer is to be continuously operated without stopping the Periodic Registration Request Timer when CM-Connected transitions from CM-IDLE. Accordingly, the terminal can drive the Periodic Registration Timer according to the value of the Periodic Registration Timer received from the end of the registration procedure. That is, the terminal can run the corresponding Timer immediately after receiving the Registration Accept, checking the Periodic Registration Request Timer included therein, and confirming that the Timer is applied to the Periodic Registration Timer Running Policy. The terminal continues to operate the timer even when the CM-IDLE transitions to CM-Connected, operates the timer even while maintaining the connected state, and continues to operate until the timer expires. If the periodic registration timer running policy includes an indicator that is a one-time policy, the terminal releases the application of the policy after the periodic registration request timer expires. In other words, the periodic registration timer operation is performed as a general operation (timer stops when transitioning from CM-IDLE to CM-Connected, and restarts from the initial value of the timer when transitioning from CM-Connected to CM-Idle). The AMF can perform this Timer after sending the Registration Accept message to the terminal. The Periodic Registration Timer value driven by the AMF end may have a slightly larger value than the value allocated to the UE. For example, it can have a value of 5 minutes or so. This is a situation in which a time delay may occur due to a failure such as a radio situation when the terminal performs the periodic registration procedure, and the AMF cannot receive the Registration Request message from the terminal even after the periodic registration timer expires during the time due to this failure. At this time, the AMF is to prevent the terminal from determining that implicit deletion has been performed. As AMF drives a timer with a slightly larger value, even if there is a delay in performing the registration procedure due to a failure in the wireless situation, the terminal can correctly perform the registration procedure without determining that the terminal is implicit detached.

Through step 5, the terminal can notify the completion of the registration procedure. This procedure can be omitted. According to an embodiment of the present invention, the terminal may send an acknowledgment that the Periodic Registration Timer Running Policy received in step 4 will be applied to the AMF through the Registration Complete message. Upon receiving this, the AMF determines that the UE will apply the Periodic Registration Timer Running Policy, and accordingly drives the Periodic Registration Timer at the AMF end. Since the terminal acknowledges that it applies the Periodic Registration Timer Running Policy, the AMF continues to operate the corresponding timer even when the terminal's connection state transitions from CM-IDLE to CM-Connected, as well as the terminal operation. Is operated, and continues to operate until Timer expires.

After completing the registration procedure, the terminal, which has been permitted to operate in the MICO mode, transitions to the IDLE state and operates in the MICO mode. Accordingly, the Periodic Registration Timer is driven. If the terminal decides to apply the Periodic Registration Timer Running Policy, before transitioning to the IDLE state, i.e., receives the Periodic Registration Timer Running Policy, and immediately after receiving the Periodic Registration Timer value for this, the UE can drive the Periodic Registration Timer. . While the terminal is in MICO mode, the network cannot paging the terminal. When the terminal operates a long DRX cycle other than the MICO mode, the network cannot paging the terminal while the terminal is in the DRX sleep cycle. However, when there is data or signaling to be sent to the network, the terminal can wake up and communicate with the network at any time according to step 6. If the AMF has a newly configured Scheduled Communication Time value, the AMF may perform an operation of updating the Periodic Registration Timer and Periodic Registration Timer Running Policy to the terminal accordingly through the UE Configuration Update procedure.

According to an embodiment of the present invention, as in step 7a, when the configured Periodic Registration Timer expires, the terminal wakes up and accesses the network, and performs a Registration Request operation to transition to the Connected state. Upon receiving this, the AMF transitions the state of the terminal to Connected. According to an embodiment of the present invention, the AMF notifies the SMF for the PDU session or DNN for which the Scheduled Communication Time is set, and notifies the UE's reachability, and activates the user plane of the UE or the data path of the UE to transmit scheduled downlink data. You can let it go.

In step 7a, the terminal may be in a CM-Connected state. That is, the periodic registration timer may expire while the terminal accesses the network to transmit and receive data for the data transmission operation. In this case, since the terminal is already connected to the network, there is no need to perform the registration procedure when the timer expires for network access. According to an embodiment of the present invention, the terminal may perform the following operations. First, if the Periodic Registration Timer Running Policy is set and the Periodic Registration Timer is driven accordingly, the terminal may decide not to perform the Periodic Registration procedure when the Timer expires in the Connected state based on this criterion. Since the Timer has expired, the UE does not restart the Periodic Registration Timer until it transitions to CM-IDLE. After completing data transmission and reception, the terminal switches to CM-IDLE and then drives the Periodic Registration Timer again. Alternatively, if the terminal has set the Periodic Registration Timer Running Policy and operates the Periodic Registration Timer accordingly, when the Timer expires in the CM-Connected state, the corresponding Timer can be restarted immediately from the time when the Periodic Registration Timer expires. In other words, you can start the Timer right away without waiting for the transition to CM-IDLE. In AMF, if the periodic registration timer expires when the terminal to which the periodic registration timer running policy is applied is in the CM-connected state, the periodic registration timer can be restarted immediately from the expired time. At this time, if the UE receives an indicator indicating whether the corresponding policy is one-time or continuous in the Periodic Registration Timer Running Policy from the AMF, the UE may perform the following operation according to this indicator. If the Periodic Registration Timer Running Policy is one-time, the terminal releases the Periodic Registration Timer Running Policy after the Periodic Registration Timer expires in the Connected state. In other words, Periodic Registration Timer Running Policy is no longer applied. If the Periodic Registration Timer Running Policy is continuously applied, the UE continues to maintain the Periodic Registration Timer Running Policy after the Periodic Registration Timer expires in the Connected state. Accordingly, after the Timer expires in the CM-Connected state, the Timer may be restarted again, and the Timer may be driven according to the Periodic Registration Timer Running Policy. Second, the terminal can perform the periodic registration procedure in the connected state. Although the Timer expires and the terminal is in the connected state, if the terminal has set the Periodic Registration Timer Running Policy and has started the Periodic Registration Timer accordingly, it is decided to perform the Periodic Registration procedure when the Timer expires in the Connected state based on this criterion. I can. Through this procedure, it can be confirmed that the terminal reassigns the Periodic Registration Timer, receives a new Periodic Registration Timer Running Policy, or does not apply the Periodic Registration Timer Running Policy any more. If the AMF does not include the Periodic Registration Timer Running Policy in the Registration Accept message, the UE may determine that the Periodic Registration Timer Running Policy is no longer applied.

In the AMF, when the Periodic Registration Timer running in the AMF end for the terminal expires, if the terminal is in a Connected state, and if the Periodic Registration Timer Running Policy has been applied, the AMF according to an embodiment of the present invention follows step 13 UE Configuration Update procedure can be performed. This is to update the periodic registration timer value and periodic registration timer running policy information according to the scheduled communication time to the terminal. If the AMF determines that the Scheduled Communication Time is no longer valid, that is, there is no scheduled communication time set, or that it is no longer necessary to apply the Schedueld Communication Time, the AMF informs the UE that the Periodic Registration Timer Running Policy has been released through the UE Configuration Update procedure. Can be judged. As another example, if there is a valid Scheduled Communication Time set after the current time, the AMF may determine to set the Periodic Registration Timer according to the corresponding Scheduled Communication Time and also apply the Periodic Registration Timer Running Policy. The AMF may include a Periodic Registration Timer value determined through the above procedure and a Periodic registration timer running policy in the UE Configuration Update Command message. The periodic registration timer running policy may mean an indicator that the Periodic Registration Timer should continue to operate regardless of the CM-IDLE/CM-Connected transition. In addition, it may include an indicator indicating whether the corresponding periodic registration timer running policy is one-time or should be maintained continuously. The UE transmits a response message to the UE Configuration Update Command sent by the AMF, and at this time, it may acknowledge that the transmitted information has been well applied. When it is determined that the AMF no longer applies the Periodic Registration Timer Running Policy, the UE Configuration Update Command message may include an identifier indicating termination of the Periodic Registration Timer Running Policy. After the AMF determines that the terminal has applied the Periodic Registration Timer Running Policy, the UE Configuration Update Command message sent to the corresponding terminal may include an identifier indicating termination of the Periodic Registration Timer Running Policy. The UE transmits a response message to the UE Configuration Update Command sent by the AMF, and at this time, it may acknowledge that the transmitted information has been well applied.

Alternatively, the AMF may only perform an operation of triggering the UE to perform a Registration Request, instead of including the Periodic Registration Timer and Periodic Registration Timer running policy information as described above in the UE Configuration Update Command message. Therefore, the AMF can send an indication that the registration procedure needs to be performed to the UE by including it in the UE Configuration Update Command message. In this case, the AMF may include an indicator that the terminal can use the MICO mode. The terminal transmits a response message to the UE Configuration Update Command sent by the AMF. After that, the terminal performs the registration procedure as in step 4.

Step 7b indicates that Downlink Data has occurred as scheduled in Scheduled Communication Time. After receiving the downlink data from the data network, the UPF notifies the SMF and activates the data path for transmitting the data to the terminal. This process can follow the NW-initiated Service Request. According to the NW-initiated Service Requset, the network paging the terminal, and the awakened terminal sends a Service request, and the terminal transitions to the connected state.

The terminal may send a Registration Request message to the AMF as in step 8 according to the determination operation according to step 7a. Upon receiving this, the AMF can maintain the connection of the terminal for a certain period of time until a downlink data notification for the terminal is received. This is because if the terminal returns to the IDLE state, it may become Unreachable again. If downlink data for the terminal arrives while the connection of the terminal is maintained, and the SMF informs the AMF that the data path for the terminal should be activated, the AMF can perform a procedure for activating the corresponding data path. As another example, in step 8, the terminal may include information on the PDU session to activate the data path in “PDU Session to be Activated” along with the Registration Request. This is because the terminal applies the Periodic Registration Timer Running Policy, so it is determined that there will be scheduled communication and is included, and thus, the data path is activated by requesting to activate the corresponding PDU session. This has the effect that the SMF can omit the procedure of notifying the AMF that the Donwlink Data has arrived. Upon receiving this, the AMF may trigger the activation of the Data Path to the SMF for the corresponding PDU Session. After the data path for transmitting data to the terminal is activated by the above three operations, the data is transmitted to the terminal according to step 9.

According to steps 10 and 11, the Scheduled Communication Time is stored in the context for the terminal in the UDM, so that the AMF or SMF can obtain it. AF can provide corresponding information through NEF, NEF delivers it to UDM, and UDM can classify and store the corresponding information in the Session Management Context of the terminal. Alternatively, according to steps 10 and 11, the NEF directly transmits the scheduled communication time for a specific terminal to the AMF or SMF, so that the AMF or SMF may obtain the corresponding value. Since the scheduled communication time is provided to the UDM for a specific terminal indicated by the external ID or external group ID from the 3rd party, the UDM can store the scheduled communication time value for each external ID or external group ID of the terminal in the SM context. This is because the terminal may have multiple External IDs or External Group IDs. Alternatively, the scheduled communication time may be provided to UDM as a value for a specific data network name (DNN) for a specific terminal indicated by an external ID or external group ID from a 3rd party. In this case, the UDM may store a Scheduled Communication Time value in the SM context according to the DNN value for each External ID or External Group ID of the terminal. This is to support the case where the terminal has multiple External IDs or External Group IDs, or when subscriber information is configured so that the terminal can use multiple DNNs for NIDD service. That is, the Scheduled Communication Time is set in UDM subscriber information for each terminal, and several may be set for each External ID or External Group ID, or for each External ID/External Group ID and DNN.

Step 12 is an operation subsequent to step 11 when the SMF obtains information about the scheduled communication time from the UDM as an SM context for the terminal or the SMF obtains it from the NEF. The SMF can determine when downlink data transmission to the corresponding terminal occurs by looking at the Scheduled Communication Time. Since the SMF needs to be reachable to the 5G network at the corresponding time, the SMF can send a message requesting the reachability of the terminal to the AMF in charge of mobility management of the terminal. This is one of the APIs provided by the AMF and may be different from the name for step 12 in the drawing. However, if the SMF is a message that provides the AMF with the scheduled communication time of a specific terminal, it can be said to correspond to the message proposed in the present invention. For example, it can be delivered using an API provided by SMF such as Nsmf_PDU Session Update SM Context. In step 12, the SMF provides the ID of the terminal (an ID that can identify the terminal in AMF, for example, SUCI (Subscription Concealed Identifier) or SUPI (Subscription Permanent Identifier, old IMSI may correspond to this), or External ID). It includes, includes the Scheduled Communication Time obtained from step 12, and may include a PDU session ID indicating a corresponding PDU session. The reason for including the PDU Session ID is that when the UE uses data communication with multiple PDU Sessions, the UE sends a Service Request at the Scheduled Communication Time, and it is possible to determine which PDU Session to activate when awakening. In addition, when the terminal uses data communication with multiple PDU sessions, it is for the AMF to distinguish which PDU session is the scheduled communication time. When the AMF can receive multiple SMFs or multiple Scheduled Communication Time values from one SMF, it can identify the Scheduled Communication Time values for each PDU session by looking at the PDU Session ID included in Message 2-2.

The message according to step 12 or the AMF that knows the scheduled communication time for the terminal through step 10 stores this in the context of the terminal. Also, a Periodic Registration Timer value can be assigned based on this. The AMF may determine to apply the periodic registration timer running policy to the terminal so that the terminal can wake up and access the network at the scheduled communication time. That is, when the terminal transitions from CM-IDLE to CM-Connected, the Periodic Registration Timer is instructed not to stop, so that the Periodic Registration Timer continues to operate even when the terminal is connected, and the Periodic Registration Timer expires later in the CM-IDLE state. When it is done, it can connect to the network by performing the registration procedure so that the terminal can attach to the network when scheduled communication occurs. The AMF performs step 13 to deliver the Periodic Registration Time value and the Periodic Registration Timer running policy according to the Scheduled Communication Time, or when the terminal leaves the Reachable state for a specific time from the network to reduce power consumption through the Registration procedure. When an operation is requested, for example, when a MICO mode is requested through a registration procedure, it can be transmitted to the terminal.

According to step 13, the AMF may determine to adjust the periodic registration request timer value of the terminal according to the scheduled communication time set to the terminal. In addition, it is possible to determine the policy for the periodic registration request timer operation of the terminal. That is, even if the terminal transitions from CM-IDLE to CM-Connected, it can be determined to apply a policy for an operation that continues to operate without stopping the Periodic Registration Request Timer. As another example, if the Scheduled Communication Time for the terminal is a one-time time, that is, indicates a specific time (UTC 12:00, 2019-02-12), the Periodic Registration Request Timer Policy may be determined as a one-time policy. As another example, when the Scheduled Communication Time for the terminal is a regular time, that is, for example, every Monday at 9 am, or every day at 12 noon, it may be decided to apply the Periodic Registration Request Timer Policy as a policy that continues to apply. The AMF can set the indicator accordingly, and this can be delivered to the terminal during the registration procedure or the UE configuration update procedure.

The AMF may perform the UE Configuration Update procedure according to step 13 to make the terminal wake up at the scheduled communication time, to transmit the Periodic Registration Timer to the terminal, or to perform the registration procedure. This is to deliver the periodic registration timer value and the periodic registration timer running policy according to the scheduled communication time to the terminal. The AMF may include a Periodic Registration Timer value determined through the above procedure and a Periodic registration timer running policy in the UE Configuration Update Command message according to step 13. The periodic registration timer running policy may mean an indicator that the Periodic Registration Timer should continue to operate regardless of the CM-IDLE/CM-Connected transition. In addition, it may include an indicator indicating whether the corresponding periodic registration timer running policy is one-time or should be maintained continuously. The UE transmits a response message to the UE Configuration Update Command sent by the AMF, and at this time, it may acknowledge that the transmitted information has been well applied.

Alternatively, the AMF may only perform an operation of triggering the UE to perform a Registration Request, instead of including the Periodic Registration Timer and Periodic Registration Timer running policy information as described above in the UE Configuration Update Command message. Therefore, the AMF can send an indication that the registration procedure needs to be performed to the UE by including it in the UE Configuration Update Command message. In this case, the AMF may include an indicator that the terminal can use the MICO mode. The terminal transmits a response message to the UE Configuration Update Command sent by the AMF. Upon receiving the trigger to perform the registration request, the terminal performs the operation according to step 1 of FIG. 2.

On the other hand, the embodiments of the present invention disclosed in the specification and drawings are only provided specific examples to easily explain the technical content of the present invention and to aid understanding of the present invention, and are not intended to limit the scope of the present invention. That is, it is apparent to those of ordinary skill in the art that other modifications based on the technical idea of the present invention can be implemented. In addition, each of the above embodiments may be combined and operated as necessary. For example, parts of the embodiments of the present invention may be combined with each other to operate a base station and a terminal.

In addition, the present specification and drawings disclose preferred embodiments of the present invention, and although specific terms are used, these are merely used in a general meaning to easily describe the technical content of the present invention and to aid understanding of the present invention. It is not intended to limit the scope of the invention. In addition to the embodiments disclosed herein, it is apparent to those of ordinary skill in the art that other modified examples based on the technical idea of the present invention can be implemented.

Claims (1)

In the control signal processing method in a wireless communication system,
Receiving a first control signal transmitted from a base station;
Processing the received first control signal; And
And transmitting a second control signal generated based on the processing to the base station.

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