TECHNICAL FIELD

The present invention relates to a UE and a communication control method. This application claims priority based on JP 2018-215877 filed on Nov. 16, 2018, the contents of which are incorporated herein by reference.

BACKGROUND ART

The 3rd Generation Partnership Project (3GPP), which undertakes activities for standardizing recent mobile communication systems, has studied System Architecture Evolution (SAE) which is a system architecture of Long Term Evolution (LTE). The 3GPP is in the process of standardizing Evolved Packet System (EPS) as a communication system for realizing an all-Internet Protocol (IP) architecture. Note that a core network constituting the EPS is called an Evolved Packet Core (EPC).

Additionally, the 3GPP recently has been studying a next-generation communication technology and a system architecture for 5th Generation (5G) mobile communication system which is a next-generation mobile communication system. Especially, as a system for achieving the 5G mobile communication system, the 3GPP is in a process of standardizing 5G System (5GS) (see NPL 1 and NPL 2). In the 5GS, technical problems attributable to connection of various terminals to a cellular network are extracted to standardize solutions.

For example, requirement conditions include optimization and diversification of a communication procedure for supporting a continual mobile communication service depending on a terminal supporting various access networks, optimization of a system architecture suitable for the optimization and diversification of the communication procedure, and the like.

CITATION LIST

Non Patent Literature

Non Patent Literature 1: 3GPP TS 23.501 v15.0.0; 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; System Architecture for the 5G system; Stage 2 (Release 15)Non Patent Literature 2: 3GPP TS 23.502 v15.0.0; 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Procedures for the 5G system; Stage 2 (Release 15)Non Patent Literature 3: 3GPP TS 24.501 v15.1.0; 3rd Generation Partnership Project; Technical Specification Group Core Network and Terminals; Non-Access-Stratum (NAS) protocol for 5G System (5GS); Stage 3 (Release 15)

SUMMARY OF INVENTION

Technical Problem

In 5GS, in addition to a mechanism that provides a function corresponding to congestion management, control signal management based on causes other than congestion management has been further studied (see NPL 1, NPL 2, and NPL 3).

However, processing is not clear in a case that the UE changes the system in the state in which congestion management is being applied.

One aspect of the present invention has been made in view of such circumstances, and an object of the present invention is to provide a mechanism and a communication control method for implementing a control signal management process based on a cause for congestion management in a case of changing the system.

Solution to Problem

A UE according to an aspect of the present invention is a User Equipment (UE, terminal apparatus) including a transmission and/or reception unit, wherein in a case that a timer for a combination of Single Network Slice Selection Assistance information (S-NSSAI) and no Data Network Name (DNN) combination is running, the transmission and/or reception unit is capable of initiating an EPS Session Management (ESM) procedure without using an Access Point Name (APN) in an EPS, and the transmission and/or reception unit receives a value of the timer included in a PDU session establishment reject message.

A communication control method according to an aspect of the present invention is a communication control method of a User Equipment (UE, terminal apparatus), wherein in a case that a timer for a combination of Single Network Slice Selection Assistance information (S-NSSAI) and no Data Network Name (DNN) combination is running, the UE is capable of initiating an EPS Session Management (ESM) procedure without using an Access Point Name (APN) in an EPS, and the UE receives a value of the timer included in a PDU session establishment reject message.

Advantageous Effects of Invention

According to one aspect of the present invention, terminal apparatuses constituting 5GS and apparatuses in a core network perform management processing, such as congestion management, for different systems, for each terminal apparatus initiated network slice and/or DNN or APN.

