CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2019-0068265, filed on Jun. 10, 2019, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety.

BACKGROUND

1. Field

The disclosure relates to a method of managing a context in a mobile communication system.

2. Description of the Related Art

In order to meet the increasing demand with respect to wireless data traffic after the commercialization of 4thgeneration (4G) communication systems, efforts have been made to develop improved 5thgeneration (5G) communication systems or pre-5G communication systems. For this reason, 5G communication systems or pre-5G communication systems are called Beyond 4G network communication systems or Post Long Term Evolution (LTE) systems.

In order to achieve a high data transfer rate, consideration is given to implementing 5G communication systems in millimeter wave (mmW) frequency bands (e.g., 60 GHz bands). In order to reduce propagation path loss of radio waves and increase a propagation distance of radio waves in the millimeter wave frequency bands, in 5G communication systems, discussions are underway about technologies such as beam-forming, massive multiple input multiple output (MIMO), full dimensional MIMO (FD-MIMO), array antenna, analog beam-forming, and large scale antenna.

Also, in order to improve networks of systems, in 5G communication systems, developments of technologies such as evolved small cell, advanced small cell, cloud radio access network (cloud RAN), ultra-dense network, device to device communication (D2D), wireless backhaul, moving network, cooperative communication, coordinated multi-points (CoMP), and interference cancellation are underway.

Furthermore, in 5G communication systems, developments of an advanced coding modulation (ACM) scheme such as hybrid frequency shift keying and quadrature amplitude modulation (FQAM) and sliding window superposition coding (SWSC) and an enhanced network access scheme such as filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), or sparse code multiple access (SCMA) are underway.

5G communication systems consider resources for various services, compared with existing 4G communication systems. For example, most representative services may include an enhanced mobile broad band (eMBB) communication service, an ultra-reliable and low latency communication (URLLC) service, a massive machine type communication (mMTC) service, and an evolved multimedia broadcast/multicast service (eMBMS). In addition, a system providing the URLLC service may be referred to as a URLLC system, and a system providing an eMBB service may be referred to as an eMBB system. Also, the terms ‘service’ and ‘system’ may be used interchangeably.

Among them, the URLLC service is a service that is newly considered in the 5G system unlike the existing 4G system, and requires satisfaction of the conditions of an ultra high reliability (for example, a packet error rate of about 10−5) and a low latency (for example, about 0.5 msec), compared to other services. In order to satisfy these strict conditions, the URLLC service may need to apply a transmission time interval (TTI) shorter than the eMBB service, and various operation methods utilizing the same are considered.

The Internet is being developed from a human-centered network via which people generate and consume information to an Internet of Things (IoT) network via which distributed components, such as things, transmit or receive information to or from each other and process the information. Internet of Everything (IoE) technology in which big data processing technology is combined with IoT technology via connection with a cloud server or the like, is emerging. To implement IoT, technical elements, such as sensing technology, a wired/wireless communication and network infrastructure, service interface technology, and security technology, are required, and thus a sensor network, machine to machine (M2M) communication, machine type communication (MTC), and the like for connection between things have recently been studied.

In IoT environments, an intelligent Internet Technology (IT) service for collecting and analyzing data generated by connected things and creating a new value in people's lives may be provided. IoT is applicable to various fields, such as smart home, smart building, smart city, smart car or connected car, smart grid, health care, smart home appliances, and advanced medical care, via fusion and combination of existing information technology (IT) with various industries.

Accordingly, various attempts are being made to apply 5G communication systems to IoT networks. For example, technology such as a sensor network, M2M communication, or MTC is implemented by 5G communication technology such as beam-forming, MIMO, or array antenna. The application of a cloud RAN as big data processing technology may also be considered as an example of convergence of 5G technology and IoT technology.

Meanwhile, due to the development of various IT technologies, pieces of network equipment have evolved into virtualized network functions (NFs) by applying virtualization technology, and the virtualized NFs may be implemented in an SW form by deviating from a physical restriction and thus may be installed/operated in several types of Cloud or data center (DC). In particular, the NFs may be freely expanded/reduced (scaling) or initiated/terminated according to service requirements, a system capacity, and a network load.

SUMMARY

Provided is a structure for and a communication method of exchanging or storing user data (Context) processed by network functions (NFs) in order to increase communication efficiency and improve a customer service quality in a 5thgeneration (5G) system.

Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments of the disclosure.

According to an embodiment of the disclosure, a method, performed by a first Session Management Function (SMF), for providing a continuous service to a user equipment (UE) includes: identifying, by the first SMF, triggering of an SMF change operation; transmitting, to an Access and Mobility Management Function (AMF), a message indicating a change in a status of a Packet Data Unit (PDU) session of the UE so as to request a procedure of changing an SMF; receiving a context request message requesting a context of the UE from a second SMF that is a target SMF; and transmitting a context request response message to the second SMF.

The SMF change operation may be triggered in response to a request by Operations, Administration and Maintenance (OAM), and the request by the OAM may include identification information of the second SMF.

The method may further include: transmitting, to the AMF, a message requesting notification of information about a change in a status of the UE; and receiving, from the AMF, a notification message indicating the change in the status of the UE.

The message indicating the change in the status of the PDU session with respect to the UE may include at least one of identification information of the second SMF, context identification (ID), or ID information of the UE.

The context request response message may include the context of the UE which is requested by the second AMF, and the context may include information about a User Plane Function (UPF) to be selected by the second SMF.

According to an embodiment of the disclosure, a method, performed by an Access and Mobility Management Function (AMF), for providing a continuous service to a user equipment (UE) includes: receiving, from a first Session Management Function (SMF), a message indicating a change in a status of a Packet Data Unit (PDU) session of the UE so as to request a procedure of changing an SMF; selecting a second SMF that is a target SMF; transmitting, to the second SMF, a request message of requesting generation of a new session; and receiving, from the second SMF, a response message with respect to the request message of requesting generation of the new session.

The selecting of the second SMF may be performed by the AMF or is performed through a Service Communication Proxy (SCP).

The method may further include: receiving, from the first SMF, a message requesting notification of information about a change in a status of the UE; monitoring the change in the status of the UE; and transmitting, to the first SMF, a notification message indicating the change in the status of the UE, based on a result of the monitoring.

The message indicating the change in the status of the PDU session with respect to the UE may include at least one of identification information of the second SMF, context identification (ID), or ID information of the UE, and the identification information of the second SMF may include SMF set identification information.

The second SMF may be registered in a Unified Data Management (UDM).

According to an embodiment of the disclosure, a first Session Management Function (SMF) for providing a continuous service to a user equipment (UE) includes: a transceiver; and a processor combined with the transceiver and configured to identify, by the first SMF, triggering of an SMF change operation, transmit, to an Access and Mobility Management Function (AMF), a message indicating a change in a status of a Packet Data Unit (PDU) session of the UE so as to request a procedure of changing an SMF, receive a context request message requesting a context of the UE from a second SMF that is a target SMF, and transmit a context request response message to the second SMF.

The SMF change operation may be triggered in response to a request by Operations, Administration and Maintenance (OAM), and the request by the OAM may include identification information of the second SMF.

The processor may be further configured to transmit, to the AMF, a message requesting notification of information about a change in a status of the UE, and receive, from the AMF, a notification message indicating the change in the status of the UE.

The message indicating the change in the status of the PDU session with respect to the UE may include at least one of identification information of the second SMF, context identification (ID), or ID information of the UE.

The context request response message may include the context of the UE which is requested by the second SMF, and the context may include information about a User Plane Function (UPF) to be selected by the second SMF.

According to an embodiment of the disclosure, an Access and Mobility Management Function (AMF) for providing a continuous service to a user equipment (UE) includes: a transceiver; and a processor combined with the transceiver and configured to receive, from a first Session Management Function (SMF), a message indicating a change in a status of a Packet Data Unit (PDU) session of the UE so as to request a procedure of changing an SMF, select a second SMF that is a target SMF, transmit, to the second SMF, a request message of requesting generation of a new session, and receive, from the second SMF, a response message with respect to the request message of requesting generation of the new session.

The selecting of the second SMF may be performed by the AMF or may be performed through a Service Communication Proxy (SCP).

The processor may be further configured to receive, from the first SMF, a message requesting notification of information about a change in a status of the UE, monitor the change in the status of the UE, and transmit, to the first SMF, a notification message indicating the change in the status of the UE, based on a result of the monitoring.

The message indicating the change in the status of the PDU session with respect to the UE may include at least one of identification information of the second SMF, context identification (ID), or ID information of the UE, and the identification information of the second SMF may include SMF set identification information.

The second SMF may be registered in a Unified Data Management (UDM).

Before undertaking the DETAILED DESCRIPTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation; the term “or,” is inclusive, meaning and/or; the phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; and the term “controller” means any device, system or part thereof that controls at least one operation, such a device may be implemented in hardware, firmware or software, or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely.

Moreover, various functions described below can be implemented or supported by one or more computer programs, each of which is formed from computer readable program code and embodied in a computer readable medium. The terms “application” and “program” refer to one or more computer programs, software components, sets of instructions, procedures, functions, objects, classes, instances, related data, or a portion thereof adapted for implementation in a suitable computer readable program code. The phrase “computer readable program code” includes any type of computer code, including source code, object code, and executable code. The phrase “computer readable medium” includes any type of medium capable of being accessed by a computer, such as read only memory (ROM), random access memory (RAM), a hard disk drive, a compact disc (CD), a digital video disc (DVD), or any other type of memory. A “non-transitory” computer readable medium excludes wired, wireless, optical, or other communication links that transport transitory electrical or other signals. A non-transitory computer readable medium includes media where data can be permanently stored and media where data can be stored and later overwritten, such as a rewritable optical disc or an erasable memory device.

Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases.

