Method and apparatus for providing always online attributes of PDU sessions and for providing interworking aspects with respect to always online PDU sessions

Abstract

A method, apparatus, and computer program product may be provided for providing an always online property as a PDU session, providing an interworking aspect with respect to an always online PDU session, and enabling a network to determine whether a PDU session will be an always online PDU session. An example method may include receiving a PDU session setup request message from a UE, the PDU session setup request message including an IE requested by an always-online PDU session, the IE being set to a value indicating a request to establish a new always-online PDU session (e.g., requesting an always-online PDU session), the value indicating that the new always-online PDU session is set to a value indicating that the new always-online PDU session is set to a value indicating that the new always-online PDU session is set to a value indicating that the new always-online PDU session is set. And upon determining that the requested PDU session should be established as an always online PDU session, causing a PDU session establishment acceptance message to be transmitted, the PDU session establishment acceptance message comprising an always online PDU session indication IE set to a value indicating a PDU session requiring always online ("PDU session requiring always online").

Description

[0001] This application is a divisional application of the invention patent application with international application number PCT / US2019 / 045575, international application date August 7, 2019, entering the Chinese national phase on March 3, 2021, Chinese national application number 201980057659.1, and invention name “Method and device for providing always-online attributes of PDU sessions and for providing intercommunication aspects regarding always-online PDU sessions”. Technical Field

[0002] Example embodiments generally relate to a method and apparatus for providing always-on as an attribute of a protocol data unit (PDU) session and for providing interworking aspects regarding always-on PDU sessions, and more particularly for providing functionality that enables a network to determine whether a PDU session can be an always-on PDU session. Background of the Invention

[0003] In 5th generation wireless systems (5G), a user equipment (UE) cannot initiate a service request procedure while another service request procedure is in progress. That is, a new service request procedure can only begin when the old one is complete. This limitation may cause some delays for services that use PDU sessions, requiring the PDU session to be reactivated during a new service request procedure.

[0004] Because this delay can cause problems for latency-sensitive services, an "always-on PDU session" has been introduced. An always-on PDU session is a PDU session that must activate user plane resources during the transition from 5G MM idle mode to 5G MM connected mode. This PDU session can be established based on instructions from upper layers. However, the current specification (i.e., 3GPP TS 24.501) does not provide any instructions on how the upper layers in the UE can be configured to provide instructions.

[0005] Therefore, always-on PDU sessions lack network control. Specifically, the network does not know whether a PDU session is an always-on PDU session, and the network cannot set a PDU session as an always-on PDU session or a non-always-on PDU session. Because always-on PDU sessions may consume more network resources than non-always-on PDU sessions, this application introduces a solution for network control of always-on PDU sessions. Summary of the Invention

[0006] In the current specification, the "always-on" property is not considered an attribute of a PDU Session. Examples of existing PDU Session attributes include: SSC mode, PDU Session type, DNN, S-NSSAI. The commonality between these attributes should be maximized. More specifically, the UE should be able to indicate to the network via the PDU Session Setup Request message whether the UE requests the PDU Session to be always-on, because the number of user subscription checks used to determine the always-on property can be minimized. That is, if the always-on property is not required and the DNN is the Internet, the Session Management Function (SMF) can be configured to determine the PDU Session as a non-always-on PDU Session without checking the user's subscription. However, it should not be misunderstood that the network is able to determine the PDU Session as always-on. The determination of always-on can only be made when requested by the UE. However, it is up to the network to determine whether the PDU Session can be an always-on PDU Session. Because an always-on PDU Session may require session continuity during inter-system changes, interworking aspects need to be specified. The current specification lacks those interworking aspects.

[0007] According to example embodiments, a method, apparatus, and computer program product are provided for providing and / or utilizing always-on as an attribute of a protocol data unit (PDU) session and providing interworking aspects regarding always-on PDU sessions. Furthermore, a method, apparatus, and computer program product are provided for providing functionality enabling a network to determine whether a PDU session can be an always-on PDU session.

[0008] In some embodiments, a method for performing a service request process may be provided, the method comprising: receiving a protocol data unit (PDU) session establishment request message from a user equipment (UE), the PDU session establishment request message being configured to indicate a request to establish a new PDU session, the PDU session establishment request message including an information element (IE) requested for an always-online PDU session, the IE requested for an always-online PDU session being set to a value indicating a request to establish a new always-online PDU session, or the PDU session establishment request message not including the IE requested for an always-online PDU session; and determining whether the requested PDU session should be established as an always-online PDU session based on the IE requested for the always-online PDU session, based on a local policy or configuration and if the IE requested for the always-online PDU session is available.

[0009] In some embodiments, the method may further include: after determining that the requested PDU session should be established as an always-on PDU session, causing transmission of a PDU session establishment accept message, the PDU session establishment accept message including an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating "always-on PDU session required".

[0010] In some embodiments, the method may further include: after determining that the requested PDU session should not be established as an always-on PDU session, causing transmission of a PDU session establishment accept message, if the UE includes the IE requested by the always-on PDU session in the PDU session establishment request message, the PDU session establishment accept message includes an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating that "always-on PDU session is not allowed"; or if the UE does not include the IE requested by the always-on PDU session in the PDU session establishment request message, the PDU session establishment accept message does not include the always-on PDU session indication IE.

[0011] In some embodiments, when the always-on PDU session indication IE is included in the PDU session establishment accept message and the always-on PDU session indication IE is set to a value indicating "always-on PDU session required", the method may further include: causing the UE to treat the established PDU session as an always-on PDU session.

[0012] In some embodiments, in the following cases: the always-online PDU session indication IE is not included in the PDU session establishment accept message, or the always-online PDU session indication IE is included in the PDU session establishment accept message and the always-online PDU session indication IE is set to a value indicating that "always-online PDU session is not allowed", the method may also include: causing the UE to not regard the established PDU session as an always-online PDU session.

[0013] In some embodiments, the method may further include maintaining the always-on PDU session indication at the UE and the SMF after an inter-system change from N1 mode to S1 mode.

[0014] In some embodiments, the method may further include determining whether a PDU session transmitted from an Evolved Packet System (EPS) is an always-on PDU session based on the always-on PDU session indication after an inter-system change from S1 mode to N1 mode.

[0015] In some embodiments, a device for performing a service request process may be provided, the device comprising at least one processor and at least one memory comprising computer program code, the at least one memory and the computer program code being configured to, together with the processor, cause the device to at least: receive a protocol data unit (PDU) session establishment request message from a user equipment (UE), the PDU session establishment request message being configured to indicate a request to establish a new PDU session, the PDU session establishment including an information element (IE) requested for an always-online PDU session, the IE requested for an always-online PDU session being set to a value indicating a request to establish a new always-online PDU session, or the PDU session establishment request message not including the IE requested for an always-online PDU session; and determine whether the requested PDU session should be established as an always-online PDU session based on the IE requested for the always-online PDU session if the IE requested for the always-online PDU session is available.

[0016] In some embodiments, the at least one memory and the computer program code are also configured to, together with the processor, cause the device to: after determining that the requested PDU session should be established as an always-on PDU session, cause the transmission of a PDU session establishment accept message, the PDU session establishment accept message including an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating "always-on PDU session required".

[0017] In some embodiments, the at least one memory and the computer program code are also configured to, together with the processor, cause the device to: after determining that the requested PDU session should not be established as an always-on PDU session, cause the transmission of a PDU session establishment accept message, if the UE includes the IE requested by the always-on PDU session in the PDU session establishment request message, then the PDU session establishment accept message includes an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating that "always-on PDU session is not allowed"; or if the UE does not include the IE requested by the always-on PDU session in the PDU session establishment request message, then the PDU session establishment accept message does not include the always-on PDU session indication IE.

[0018] In some embodiments, in the following case: the always-online PDU session indication IE is included in the PDU session establishment accept message and the always-online PDU session indication IE is set to a value indicating "always-online PDU session required", the at least one memory and the computer program code may also be configured to, together with the processor, cause the device to: cause the UE to treat the established PDU session as an always-online PDU session.

[0019] In some embodiments, in the following circumstances: the always-online PDU session indication IE is not included in the PDU session establishment accept message, or the always-online PDU session indication IE is included in the PDU session establishment accept message and the always-online PDU session indication IE is set to a value indicating that "always-online PDU session is not allowed", the at least one memory and the computer program code may also be configured to, together with the processor, cause the device to: cause the UE not to regard the established PDU session as an always-online PDU session.

[0020] In some embodiments, the at least one memory and the computer program code may also be configured to, together with the processor, cause the apparatus to: maintain the always-on PDU session indication at the UE and SMF after an inter-system change from N1 mode to S1 mode.

[0021] In some embodiments, the at least one memory and the computer program code may also be configured to, together with the processor, cause the device to: determine, after an inter-system change from S1 mode to N1 mode, whether a PDU session transmitted from an evolved packet system (EPS) is an always-on PDU session based on the always-on PDU session indication.

[0022] In some embodiments, a computer program product operable for performing a service request process may be provided, the computer program product comprising at least one non-transitory computer-readable storage medium storing computer-executable program code instructions, the computer-executable program code instructions comprising program code instructions for performing the following operations: receiving a protocol data unit (PDU) session establishment request message from a user equipment (UE), the PDU session establishment request message being configured to indicate a request to establish a new PDU session, the PDU session establishment request message including an always-online PDU session requested information element (IE), the always-online PDU session requested IE being set to a value indicating a request to establish a new always-online PDU session, or the PDU session establishment request message not including the always-online PDU session requested IE; and determining whether the requested PDU session should be established as an always-online PDU session based on the always-online PDU session requested IE based on local policy or configuration and if the always-online PDU session requested IE is available.

[0023] In some embodiments, the computer-executable program code instructions may also include program code instructions for performing the following operations: after determining that the requested PDU session should be established as an always-on PDU session, causing the transmission of a PDU session establishment accept message, the PDU session establishment accept message including an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating "always-on PDU session required".

[0024] In some embodiments, the computer-executable program code instructions may also include program code instructions for performing the following operations: after determining that the requested PDU session should not be established as an always-on PDU session, causing the transmission of a PDU session establishment accept message, if the UE includes the IE requested by the always-on PDU session in the PDU session establishment request message, then the PDU session establishment accept message includes the always-on PDU session indication IE, wherein the always-on PDU session indication IE is indicated by a value of "always-on PDU session not allowed"; or if the UE does not include the IE requested by the always-on PDU session in the PDU session establishment request message, then the PDU session establishment accept message does not include the always-on PDU session indication IE.

[0025] In some embodiments, in the following case: the always-online PDU session indication IE is included in the PDU session establishment acceptance message and the always-online PDU session indication IE is set to a value indicating "always-online PDU session required", the computer-executable program code instructions may also include program code instructions for performing the following operations: causing the UE to treat the established PDU session as an always-online PDU session.

[0026] In some embodiments, in the following circumstances: the always-online PDU session indication IE is not included in the PDU session establishment accept message, or the always-online PDU session indication IE is included in the PDU session establishment accept message and the always-online PDU session indication IE is set to a value indicating that "always-online PDU session is not allowed", the computer-executable program code instructions may also include program code instructions for performing the following operations: causing the UE to not regard the established PDU session as an always-online PDU session.

[0027] In some embodiments, the computer-executable program code instructions may further include program code instructions for maintaining the always-on PDU session indication at the UE and SMF after an inter-system change from N1 mode to S1 mode.

[0028] In some embodiments, the computer-executable program code instructions may also include program code instructions for performing the following operations: after an inter-system change from S1 mode to N1 mode, determining whether a PDU session transmitted from an evolved packet system (EPS) is an always-on PDU session based on the always-on PDU session indication.

[0029] In some embodiments, a device for performing a service request process may be provided, the device comprising: a device for receiving a protocol data unit (PDU) session establishment request message from a user equipment (UE), the PDU session establishment request message being configured to indicate a request to establish a new PDU session, the PDU session establishment request message including an information element (IE) requested for an always-online PDU session, the IE requested for an always-online PDU session being set to a value indicating a request to establish a new always-online PDU session, or the PDU session establishment request message not including the IE requested for an always-online PDU session; and a device for determining whether the requested PDU session should be established as an always-online PDU session based on the IE requested for the always-online PDU session, based on a local policy or configuration and if the IE requested for the always-online PDU session is available.

[0030] In some embodiments, the device may also include a device for causing transmission of a PDU session establishment accept message after determining that the requested PDU session should be established as an always-on PDU session, the PDU session establishment accept message including an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating "always-on PDU session required".

[0031] In some embodiments, the device may also include a device for causing transmission of a PDU session establishment accept message after determining that the requested PDU session should not be established as an always-on PDU session, if the UE includes the IE requested by the always-on PDU session in the PDU session establishment request message, then the PDU session establishment accept message includes an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating that "always-on PDU session is not allowed"; or if the UE does not include the IE requested by the always-on PDU session in the PDU session establishment request message, then the PDU session establishment accept message does not include the always-on PDU session indication IE.

[0032] In some embodiments, in the following case: the always-online PDU session indication IE is included in the PDU session establishment acceptance message and the always-online PDU session indication IE is set to a value indicating "always-online PDU session required", the device may also include: a device for causing the UE to treat the established PDU session as an always-online PDU session.

[0033] In some embodiments, in the following cases: the always-online PDU session indication IE is not included in the PDU session establishment accept message, or the always-online PDU session indication IE is included in the PDU session establishment accept message and the always-online PDU session indication IE is set to a value indicating that "always-online PDU session is not allowed", the device may also include: a device for causing the UE to not regard the established PDU session as an always-online PDU session.

[0034] In some embodiments, the apparatus may further include means for maintaining the always-on PDU session indication at the UE and SMF after an inter-system change from N1 mode to S1 mode.

[0035] In some embodiments, the apparatus may further include means for determining whether a PDU session transmitted from an Evolved Packet System (EPS) is an always-on PDU session based on the always-on PDU session indication after an inter-system change from S1 mode to N1 mode.

[0036] In some embodiments, a method may be provided, the method comprising: causing transmission of a protocol data unit (PDU) session establishment request message, the PDU session establishment request message being configured to indicate a request to establish a new PDU session, wherein the PDU session establishment request message includes an always-online PDU session requested information element (IE) set to a value indicating a request to establish a new always-online protocol data unit (PDU) session, or the PDU session establishment request message does not include the always-online PDU session requested IE; after determining that the requested PDU session should be established as an always-online PDU session, receiving a PDU session establishment accept message, the PDU session establishment accept message including an always-online PDU session indication IE, wherein the always-online PDU session The U session indication IE is set to a value indicating that "always-on PDU session is required"; and after determining that the requested PDU session should not be established as an always-on PDU session, the PDU session establishment accept message is received, wherein if the UE includes the IE requested by the always-on PDU session in the PDU session establishment request message, the PDU session establishment accept message includes the always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating that "always-on PDU session is not allowed"; or if the UE does not include the IE requested by the always-on PDU session in the PDU session establishment request message, the PDU session establishment accept message does not include the always-on PDU session indication IE.

[0037] In some embodiments, the method may further include treating the established PDU session as an always-on PDU session when the always-on PDU session indication IE is included in the PDU session establishment accept message and the always-on PDU session indication IE is set to a value indicating "always-on PDU session required".

[0038] In some embodiments, the method may further include: not treating the established PDU session as an always-on PDU session when the always-on PDU session indication IE is included in the PDU session establishment accept message and the always-on PDU session indication IE is set to a value indicating that "always-on PDU session is not allowed".

[0039] In some embodiments, a device may be provided, comprising at least one processor and at least one memory comprising computer program code, wherein the at least one memory and the computer program code are configured to, together with the processor, cause the device to at least: cause the transmission of a protocol data unit (PDU) session establishment request message, wherein the PDU session establishment request message is configured to indicate a request to establish a new PDU session, wherein the PDU session establishment request message includes an information element (IE) requested for an always-online protocol data unit (PDU) session set to a value indicating a request to establish a new always-online protocol data unit (PDU) session, or the PDU session establishment request message does not include the IE requested for the always-online PDU session; after determining that the requested PDU session should be established as an always-online PDU session, receive a PDU session establishment accept message, wherein the PDU session establishment request message The UE receives a PDU session establishment accept message including an always-online PDU session indication IE, wherein the always-online PDU session indication IE is set to a value indicating that “always-online PDU session is required”; and after determining that the requested PDU session should not be established as an always-online PDU session, receives the PDU session establishment accept message, wherein if the UE includes the IE requested by the always-online PDU session in the PDU session establishment request message, the PDU session establishment accept message includes the always-online PDU session indication IE, wherein the always-online PDU session indication IE is set to a value indicating that “always-online PDU session is not allowed”; or if the UE does not include the IE requested by the always-online PDU session in the PDU session establishment request message, the PDU session establishment accept message does not include the always-online PDU session indication IE.

[0040] In some embodiments, the at least one memory and the computer program code are also configured to, together with the processor, cause the device to: treat the established PDU session as an always-online PDU session when the always-online PDU session indication IE is included in the PDU session establishment accept message and the always-online PDU session indication IE is set to a value indicating "always-online PDU session required".

[0041] In some embodiments, the at least one memory and the computer program code are also configured to, together with the processor, cause the device to: not regard the established PDU session as an always-online PDU session when the always-online PDU session indication IE is included in the PDU session establishment accept message and the always-online PDU session indication IE is set to a value indicating that "always-online PDU session is not allowed".

[0042] In some embodiments, a computer program product may be provided, the computer program product including at least one non-transitory computer-readable storage medium storing computer-executable program code instructions, the computer-executable program code instructions including program code instructions for performing the following operations: causing transmission of a protocol data unit (PDU) session establishment request message, the PDU session establishment request message being configured to indicate a request to establish a new PDU session, wherein the PDU session establishment request message includes an always-online protocol data unit (PDU) session requested information element (IE) set to a value indicating a request to establish a new always-online PDU session, or the PDU session establishment request message does not include the always-online PDU session requested IE; after determining that the requested PDU session should be established as an always-online PDU session, receiving a PDU session establishment accept message, the PDU session establishment request message being configured to indicate a request to establish a new PDU session. A DU session establishment accept message includes an always-online PDU session indication IE, wherein the always-online PDU session indication IE is set to a value indicating that "always-online PDU session is required"; and after determining that the requested PDU session should not be established as an always-online PDU session, the PDU session establishment accept message is received, wherein if the UE includes the IE requested by the always-online PDU session in the PDU session establishment request message, the PDU session establishment accept message includes the always-online PDU session indication IE, wherein the always-online PDU session indication IE is set to a value indicating that "always-online PDU session is not allowed"; or if the UE does not include the IE requested by the always-online PDU session in the PDU session establishment request message, the PDU session establishment accept message does not include the always-online PDU session indication IE.

[0043] In some embodiments, the computer-executable program code instructions also include program code instructions for performing the following operations: when the always-online PDU session indication IE is included in the PDU session establishment acceptance message and the always-online PDU session indication IE is set to a value indicating "always-online PDU session required", treating the established PDU session as an always-online PDU session.

[0044] In some embodiments, the computer-executable program code instructions also include program code instructions for performing the following operations: if the always-online PDU session indication IE is included in the PDU session establishment accept message and the always-online PDU session indication IE is set to a value indicating that "always-online PDU session is not allowed", the established PDU session is not regarded as an always-online PDU session.

[0045] In some embodiments, a device may be provided, comprising: a device for causing transmission of a protocol data unit (PDU) session establishment request message, the PDU session establishment request message being configured to indicate a request to establish a new PDU session, wherein the PDU session establishment request message includes an always-online PDU session requested information element (IE) set to a value indicating a request to establish a new always-online protocol data unit (PDU) session, or the PDU session establishment request message does not include the always-online PDU session requested IE; and after determining that the requested PDU session should be established as an always-online PDU session, a device for receiving a PDU session establishment accept message, the PDU session establishment accept message including an always-online PDU session indication IE, wherein the always-online the PDU session indication IE is set to a value indicating that "always-on PDU session is required"; and after determining that the requested PDU session should not be established as an always-on PDU session, a device for receiving the PDU session establishment accept message, wherein if the UE includes the IE requested by the always-on PDU session in the PDU session establishment request message, the PDU session establishment accept message includes the always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating that "always-on PDU session is not allowed"; or if the UE does not include the IE requested by the always-on PDU session in the PDU session establishment request message, the PDU session establishment accept message does not include the always-on PDU session indication IE.

[0046] In some embodiments, the device may also include the following situation: the always-online PDU session indication IE is included in the PDU session establishment acceptance message and the always-online PDU session indication IE is set to a value indicating "always-online PDU session required", a device for treating the established PDU session as an always-online PDU session.

[0047] In some embodiments, the device may also include: in the following case: the always-online PDU session indication IE is included in the PDU session establishment acceptance message and the always-online PDU session indication IE is set to a value indicating that "always-online PDU session is not allowed", a device for not treating the established PDU session as an always-online PDU session.

[0048] In some embodiments, a method may be provided, the method comprising: receiving a protocol data unit (PDU) session modification request message from a user equipment (UE), the PDU session modification request message being configured to indicate a request to modify a PDU session corresponding to a PDN connection established when in S1 mode after a first inter-system change from S1 mode to N1 mode, the PDU session modification request message comprising an information element (IE), the IE being set to a value indicating a request that the PDU session be an always-on protocol data unit (PDU) session; and determining whether the requested PDU session should be an always-on PDU session based on a local policy or configuration.

[0049] In some embodiments, after determining that the requested PDU session should be an always-on PDU session, the method further includes: causing transmission of a PDU session modification command message, the PDU session modification command message including an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating "an always-on PDU session is required".

[0050] In some embodiments, the method may also include: after determining that the requested PDU session should not be an always-on PDU session, it also includes: causing the transmission of a PDU session modification command message, the PDU session modification command message including an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating that "always-on PDU sessions are not allowed".

[0051] In some embodiments, where the always-on PDU session indication IE is included in the PDU session modification command message and the always-on PDU session indication IE is set to a value indicating "always-on PDU session required", the method further includes: causing the UE to treat the PDU session as an always-on PDU session.

[0052] In some embodiments, where the always-on PDU session indication IE is included in the PDU session modification command message and the always-on PDU session indication IE is set to a value indicating that "always-on PDU session is not allowed", the method further includes: causing the UE to not regard the PDU session as an always-on PDU session.

[0053] In some embodiments, the method may further include: after the inter-system change from S1 mode to N1 mode, determining whether the requested PDU session needs to be an always-on PDU session based on the local policy or configuration in the SMF; and after determining that the requested PDU session needs to be an always-on PDU session, setting the always-on PDU session indication IE included in the PDU session modification command message to a value indicating "always-on PDU session required".

[0054] In some embodiments, the method may further include: after the inter-system change from S1 mode to N1 mode, determining whether the requested PDU session needs to be an always-on PDU session based on the local policy or configuration in the SMF; and after determining that the requested PDU session does not have to be an always-on PDU session, setting the always-on PDU session indication IE included in the PDU session modification command message to a value indicating that "always-on PDU sessions are not allowed".

[0055] In some embodiments, a device may be provided, comprising at least one processor and at least one memory comprising computer program code, the at least one memory and the computer program code being configured to, together with the processor, cause the device to at least: receive a protocol data unit (PDU) session modification request message from a user equipment (UE), the PDU session modification request message being configured to indicate a request to modify a PDU session corresponding to a PDN connection established when in S1 mode after a first inter-system change from S1 mode to N1 mode, the PDU session modification request message including an information element (IE) set to a value indicating a request that the PDU session be an always-on protocol data unit (PDU) session; and determine, based on a local policy or configuration, whether the requested PDU session should be an always-on PDU session.

[0056] In some embodiments, the at least one memory and the computer program code are further configured to, together with the processor, cause the device to: after determining that the requested PDU session should be an always-on PDU session, cause the transmission of a PDU session modification command message, the PDU session modification command message including an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating "always-on PDU session required".

[0057] In some embodiments, the at least one memory and the computer program code are also configured to, together with the processor, cause the device to: after determining that the requested PDU session should not be an always-on PDU session, cause the transmission of a PDU session modification command message, the PDU session modification command message including an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating that "always-on PDU sessions are not allowed".

[0058] In some embodiments, the at least one memory and the computer program code are also configured to, together with the processor, cause the device to: wherein, when the always-online PDU session indication IE is included in the PDU session modification command message and the always-online PDU session indication IE is set to a value indicating "always-online PDU session required", cause the UE to treat the PDU session as an always-online PDU session.

[0059] In some embodiments, the at least one memory and the computer program code are also configured to, together with the processor, cause the device to: cause the UE not to regard the PDU session as an always-online PDU session when the always-online PDU session indication IE is included in the PDU session modification command message and the always-online PDU session indication IE is set to a value indicating that "always-online PDU session is not allowed".

[0060] In some embodiments, the at least one memory and the computer program code are further configured to, together with the processor, cause the device to: determine, after an inter-system change from S1 mode to N1 mode, whether the requested PDU session needs to be an always-on PDU session based on the local policy or configuration in the SMF; and after determining that the requested PDU session needs to be an always-on PDU session, set the always-on PDU session indication IE included in the PDU session modification command message to a value indicating "always-on PDU session required".

[0061] In some embodiments, the at least one memory and the computer program code are also configured to, together with the processor, cause the device to: determine, after an inter-system change from S1 mode to N1 mode, whether the requested PDU session needs to be an always-on PDU session based on the local policy or configuration in the SMF; and after determining that the requested PDU session does not need to be an always-on PDU session, set the always-on PDU session indication IE included in the PDU session modification command message to a value indicating that "always-on PDU session is not allowed".

[0062] In some embodiments, a computer program product may be provided, comprising at least one non-transitory computer-readable storage medium storing computer-executable program code instructions, the computer-executable program code instructions comprising program code instructions for performing the following operations: receiving a protocol data unit (PDU) session modification request message from a user equipment (UE), the PDU session modification request message being configured to indicate a request to modify a PDU session corresponding to a PDN connection established when in S1 mode after a first inter-system change from S1 mode to N1 mode, the PDU session modification request message comprising an information element (IE), the IE being set to a value indicating a request that the PDU session be an always-on protocol data unit (PDU) session; and determining whether the requested PDU session should be an always-on PDU session based on a local policy or configuration.

[0063] In some embodiments, after determining that the requested PDU session should be an always-on PDU session, the computer-executable program code instructions also include program code instructions for performing the following operations: causing transmission of a PDU session modification command message, the PDU session modification command message including an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating "always-on PDU session required".

[0064] In some embodiments, after determining that the requested PDU session should not be an always-on PDU session, the computer-executable program code instructions also include program code instructions for performing the following operations: causing transmission of a PDU session modification command message, the PDU session modification command message including an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating that "always-on PDU sessions are not allowed."

[0065] In some embodiments, where the always-on PDU session indication IE is included in the PDU session modification command message and the always-on PDU session indication IE is set to a value indicating "always-on PDU session required", the computer-executable program code instructions also include program code instructions for causing the UE to treat the PDU session as an always-on PDU session.

[0066] In some embodiments, where the always-on PDU session indication IE is included in the PDU session modification command message and the always-on PDU session indication IE is set to a value indicating that "always-on PDU session is not allowed", the computer-executable program code instructions also include program code instructions for causing the UE to not regard the PDU session as an always-on PDU session.

[0067] In some embodiments, the computer-executable program code instructions also include program code instructions for performing the following operations: after an inter-system change from S1 mode to N1 mode, determining whether the requested PDU session needs to be an always-on PDU session based on the local policy or configuration in the SMF; and after determining that the requested PDU session needs to be an always-on PDU session, setting the always-on PDU session indication IE included in the PDU session modification command message to a value indicating "always-on PDU session required".

[0068] In some embodiments, the computer-executable program code instructions also include program code instructions for performing the following operations: after an inter-system change from S1 mode to N1 mode, determining whether the requested PDU session needs to be an always-on PDU session based on the local policy or configuration in the SMF; and after determining that the requested PDU session does not need to be an always-on PDU session, setting the always-on PDU session indication IE included in the PDU session modification command message to a value indicating that "always-on PDU sessions are not allowed".

[0069] In some embodiments, a device may be provided, comprising: a device for receiving a protocol data unit (PDU) session modification request message from a user equipment (UE), the PDU session modification request message being configured to indicate a request to modify a PDU session corresponding to a PDN connection established when in S1 mode after a first inter-system change from S1 mode to N1 mode, the PDU session modification request message including an information element (IE), the IE being set to a value indicating a request that the PDU session be an always-on protocol data unit (PDU) session; and a device for determining whether the requested PDU session should be an always-on PDU session based on a local policy or configuration.

[0070] In some embodiments, the device may also include: after determining that the requested PDU session should be an always-on PDU session, a device for causing the transmission of a PDU session modification command message, the PDU session modification command message including an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating "always-on PDU session required".

[0071] In some embodiments, the device may also include: after determining that the requested PDU session should not be an always-on PDU session, a device for causing the transmission of a PDU session modification command message, the PDU session modification command message including an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating that "always-on PDU session is not allowed".

[0072] In some embodiments, when the always-online PDU session indication IE is included in the PDU session modification command message and the always-online PDU session indication IE is set to a value indicating "an always-online PDU session is required", the device also includes: a device for causing the UE to treat the PDU session as an always-online PDU session.

[0073] In some embodiments, where the always-online PDU session indication IE is included in the PDU session modification command message and the always-online PDU session indication IE is set to a value indicating that "always-online PDU session is not allowed", the device also includes: a device for causing the UE to not regard the PDU session as an always-online PDU session.

[0074] In some embodiments, the device may also include: after an inter-system change from S1 mode to N1 mode, a device for performing the following operations: determining whether the requested PDU session needs to be an always-on PDU session based on the local policy or configuration in the SMF; and after determining that the requested PDU session needs to be an always-on PDU session, setting the always-on PDU session indication IE included in the PDU session modification command message to a value indicating "always-on PDU session required".

[0075] In some embodiments, the device may also include: after an inter-system change from S1 mode to N1 mode, a device for determining whether the requested PDU session needs to be an always-on PDU session based on the local policy or configuration in the SMF; and after determining that the requested PDU session does not need to be an always-on PDU session, a device for setting the always-on PDU session indication IE included in the PDU session modification command message to a value indicating that "always-on PDU session is not allowed".

[0076] In some embodiments, a method may be provided, the method comprising: causing transmission of a protocol data unit (PDU) session modification request message, the PDU session modification request message being configured to indicate a request to modify a PDU session corresponding to a PDN connection established while in S1 mode after a first inter-system change from S1 mode to N1 mode, the PDU session modification request message comprising an information element (IE), the IE being set to a value indicating a request that the PDU session be an always-on protocol data unit (PDU) session; after determining that the requested PDU session should be an always-on PDU session, receiving a PDU session modification command message, the PDU session modification command message comprising an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating that “always-on PDU session required”; and after determining that the requested PDU session should not be an always-on PDU session, receiving a PDU session modification command message, the PDU session modification command message comprising an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating that “always-on PDU session not allowed”.

[0077] In some embodiments, the method may further include: treating the PDU session as an always-online PDU session when the always-online PDU session indication IE is included in the PDU session modification command message and the always-online PDU session indication IE is set to a value indicating "always-online PDU session required".

[0078] In some embodiments, the method may further include: not treating the PDU session as an always-online PDU session when the always-online PDU session indication IE is included in the PDU session modification command message and the always-online PDU session indication IE is set to indicate "always-online PDU session is not allowed".

[0079] In some embodiments, a device may be provided, the device comprising at least one processor and at least one memory comprising computer program code, the at least one memory and the computer program code being configured to, with the processor, cause the device to at least: cause transmission of a protocol data unit (PDU) session modification request message, the PDU session modification request message being configured to indicate a request to modify a PDU session corresponding to a PDN connection established while in S1 mode after a first inter-system change from S1 mode to N1 mode, the PDU session modification request message comprising an information element (IE) set to indicate that the PDU session is an always-on protocol data unit (PDU) session. U) session; after determining that the requested PDU session should be an always-on PDU session, receiving a PDU session modification command message, the PDU session modification command message including an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating that "always-on PDU session is required"; and after determining that the requested PDU session should not be an always-on PDU session, receiving a PDU session modification command message, the PDU session modification command message including an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating that "always-on PDU session is not allowed".

[0080] In some embodiments, the at least one memory and the computer program code are also configured to, together with the processor, cause the device to: treat the PDU session as an always-online PDU session when the always-online PDU session indication IE is included in the PDU session modification command message and the always-online PDU session indication IE is set to a value indicating "always-online PDU session required".

[0081] In some embodiments, the at least one memory and the computer program code are also configured to, together with the processor, cause the device to: not treat the PDU session as an always-online PDU session when the always-online PDU session indication IE is included in the PDU session modification command message and the always-online PDU session indication IE is set to a value indicating that "always-online PDU session is not allowed".

[0082] In some embodiments, a computer program product may be provided, the computer program product including at least one non-transitory computer-readable storage medium storing computer-executable program code instructions, the computer-executable program code instructions including program code instructions for performing the following operations: causing transmission of a protocol data unit (PDU) session modification request message, the PDU session modification request message being configured to indicate a request to modify a PDU session corresponding to a PDN connection established while in S1 mode after a first inter-system change from S1 mode to N1 mode, the PDU session modification request message including an information element (IE) set to indicate that the PDU session is an always-on protocol data unit. a value requested for a data unit (PDU) session; after determining that the requested PDU session should be an always-on PDU session, receiving a PDU session modification command message, the PDU session modification command message including an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating that "always-on PDU session is required"; and after determining that the requested PDU session should not be an always-on PDU session, receiving a PDU session modification command message, the PDU session modification command message including an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating that "always-on PDU session is not allowed".

[0083] In some embodiments, the computer-executable program code instructions also include program code instructions for performing the following operations: when the always-online PDU session indication IE is included in the PDU session modification command message and the always-online PDU session indication IE is set to a value indicating "always-online PDU session required", the PDU session is regarded as an always-online PDU session.

[0084] In some embodiments, the computer-executable program code instructions also include program code instructions for performing the following operations: if the always-online PDU session indication IE is included in the PDU session modification command message and the always-online PDU session indication IE is set to a value indicating that "always-online PDU session is not allowed", the PDU session is not regarded as an always-online PDU session.

[0085] In some embodiments, a device may be provided, the device comprising: means for causing transmission of a protocol data unit (PDU) session modification request message, the PDU session modification request message being configured to indicate a request to modify a PDU session corresponding to a PDN connection established when in S1 mode after a first inter-system change from S1 mode to N1 mode, the PDU session modification request message comprising an information element (IE), the IE being set to a value indicating a request that the PDU session be an always-on protocol data unit (PDU) session; and upon determining that the requested PDU session should be an always-on PDU session. After determining that the requested PDU session should not be an always-on PDU session, an apparatus for receiving a PDU session modification command message, the PDU session modification command message including an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating that "always-on PDU session is required"; and after determining that the requested PDU session should not be an always-on PDU session, an apparatus for receiving a PDU session modification command message, the PDU session modification command message including an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating that "always-on PDU session is not allowed".

[0086] In some embodiments, the device may also include: a device for treating the PDU session as an always-online PDU session when the always-online PDU session indication IE is included in the PDU session modification command message and the always-online PDU session indication IE is set to a value indicating "always-online PDU session required".

[0087] In some embodiments, the device may also include: a device for not treating the PDU session as an always-online PDU session when the always-online PDU session indication IE is included in the PDU session modification command message and the always-online PDU session indication IE is set to a value indicating that "always-online PDU session is not allowed".

[0088] Simple diagram description

[0089] Having thus generally described certain example embodiments of the present disclosure, reference will hereinafter be made to the accompanying drawings, which are not necessarily drawn to scale, and in which:

[0090] Figure 1A and Figure 1B shows a block diagram of a system that may be specifically configured according to an example embodiment of the present disclosure;

[0091] Figure 2 is a block diagram of a device that may be specifically configured according to an example embodiment of the present disclosure;

[0092] Figure 3 shows a data flow diagram illustrating an example embodiment of the present invention;

[0093] Figure 4 and Figure 5 A depiction of an example embodiment according to the present disclosure is shown, for example, by Figure 2 a flowchart of operations performed by the device;

[0094] Figure 6 shows a data flow diagram illustrating an exemplary embodiment of the present invention; and

[0095] Figure 7 and Figure 8 A depiction of an example embodiment according to the present disclosure is shown, for example, by Figure 2 Flowchart of the operations performed by the device. DETAILED DESCRIPTION

[0096] Some embodiments of the present invention are described more fully below with reference to the accompanying drawings, in which some (but not all) embodiments of the present invention are shown. In fact, various embodiments of the present invention can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure meets applicable legal requirements. Throughout the text, the same reference numerals refer to the same elements. As used herein, according to embodiments of the present invention, the terms "data", "content", "information" and similar terms are used interchangeably to refer to data that can be transmitted, received and / or stored. Therefore, any such terms should not be used to limit the spirit and scope of the embodiments of the present invention.

[0097] Additionally, as used herein, the term "circuitry" refers to: (a) a hardware-only implementation of circuitry (e.g., an implementation in analog circuitry and / or digital circuitry); (b) a combination of circuitry and a computer program product comprising software and / or firmware instructions stored on one or more computer-readable memories that work together to cause a device to perform one or more functions described herein; or (c) circuitry, such as microprocessor(s) or a portion of microprocessor(s), that requires software or firmware for operation, even if the software or firmware is not actually present. This definition of "circuitry" applies to all uses of this term herein, including in any claims. As another example, as used herein, the term "circuitry" also includes an implementation comprising one or more processors and / or portions thereof and accompanying software and / or firmware. As another example, as used herein, the term "circuitry" also includes baseband integrated circuits or application processor integrated circuits, such as those used in mobile phones or servers, cellular network devices, other network devices, field programmable gate arrays, and / or other computing devices.

[0098] As defined herein, "computer-readable storage media," which refer to physical storage media (eg, volatile or non-volatile memory devices), can be distinguished from "computer-readable transmission media," which refer to electromagnetic signals.

[0099] A method, apparatus, and computer program product may be provided for providing always-on as an attribute of a PDU session. A method, apparatus, and computer program product may also be provided for providing interworking aspects regarding always-on PDU sessions. A method, apparatus, and computer program product may also be provided for providing functionality that enables a network to determine whether a PDU session may be an always-on PDU session.

[0100] 1, which illustrates an example system supporting communication between a plurality of stations 10 and one or more radio base stations / access points 12 (e.g., a high-density system scenario in which multiple radio base stations / access points may be deployed over a geographic area and may operate on the same frequency channels), each of which may communicate with one or more stations and, in one embodiment, a large number of stations. The radio base stations / access points may, in turn, communicate with a network 14. While the radio base stations / access points may communicate via 5G's Long Term Evolution (LTE) or Long Term Evolution-Advanced (LTE-A) networks, other networks may support communications between access points including access points configured according to Wideband Code Division Multiple Access (W-CDMA), CDMA2000, Global System for Mobile Communications (GSM), General Packet Radio Service (GPRS), IEEE 802.11 standards (including, for example, IEEE 802.11ah or 802.11ac standards, or other updated amendments thereto), Wireless Local Access Networks (WLANs), Worldwide Interoperability for Microwave Access (WiMAX) protocols, Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN), and / or similar standards, as well as other standards for, for example, multi-domain networks, which may include industrial wireless communication networks such as WirelessHART, Bluetooth, ZigBee, and / or similar networks.

[0101] The radio base station / access point 12 and the station 10 can communicate via wired communication, but most commonly communicate via wireless communication. For example, the radio base station / access point and the station can communicate in the sub-1 GHz frequency band defined by the IEEE 802.11ah standard or in the 5 GHz frequency band defined by, for example, the IEEE 802.11ac standard. The radio base station / access point can be embodied by any of a variety of network entities, such as an access point, a base station, a Node B, an evolved Node B (eNB), a radio network controller (RNC), a mobile device / workstation (e.g., a mobile phone, a smartphone, a portable digital assistant (PDA), a pager, a laptop, a tablet computer, or many other handheld or portable communication devices, computing devices, content generation devices, content consumption devices, or a combination thereof). The stations can also be embodied by various devices, such as sensors, meters, and the like. Sensors and meters can be deployed in a variety of different applications, including in utility applications for use as gas, water, electricity, and the like, in environmental and / or agricultural monitoring applications, in industrial process automation applications, in vehicle or transportation automation applications, in healthcare and fitness applications, in building automation and control applications, and / or in temperature sensing applications. In some embodiments, stations embodied by sensors or meters can be used to backhaul sensor and meter data. Alternatively, these stations can be embodied by mobile terminals or user equipment (UE), such as mobile communication devices, such as mobile phones, smartphones, portable digital assistants (PDAs), pagers, laptops, tablet computers, or any of a variety of other handheld or portable communication devices, computing devices, content generation devices, content consumption devices, or any combination thereof. In embodiments where the stations are embodied by mobile terminals, communication between access points and stations can be used to extend the range of Wi-Fi or another wireless local area network (WLAN), for example, by extending the range of a hotspot, and to reduce the traffic that may be carried by the cellular or other network.

[0102] The radio base station / access point 12 and / or the station 10 may be embodied as or otherwise include a device 20 that is specifically configured to perform the functions of the corresponding means, such as Figure 2 . Although the apparatus may be used, for example, by a radio base station / access point or station, it should be noted that the components, devices, or elements described below may not be required, and thus some may be omitted in certain embodiments. In addition, some embodiments may include additional or different components, devices, or elements than those shown and described herein.

[0103] Figure 1B The principles of the 5G architecture in the current 3GPP draft specification are shown. In particular, Figure 1Bis a networked system 100 according to an example embodiment of the present disclosure. Figure 1B Specifically illustrated is a user equipment (UE) 102, which can communicate with a radio access network (RAN) 104, an access and mobility management function (AMF) 108, and a user plane function (UPF) 106. The AMF 108 can, in turn, communicate with core network services including a session management function (SMF) 110 and a policy control function (PCF) 114. The core network services can also communicate with an application server / application function (AS / AF) 112. Other networking services also include a network slice selection function (NSSF) 122, an authentication server function (AUSF) 120, a user data management (UDM) 118, and a data network (DN) 116.

[0104] Regardless of the type of device embodying the radio base station / access point 12 and / or station 10, UE 102, any network device including but not limited to SMF 110, or any other device shown, the radio base station / access point 12 and / or station 10, UE 102, or any other device shown may include, for example, Figure 2 20 is shown as being in communication with one another, and thus, devices or elements shown as being in communication should be understood to be parts of the same device or element.

[0105] In some embodiments, the processor 22 (and / or an auxiliary processor or coprocessor or any other processing circuit system associated with the processor in some way) can communicate with the memory device 24 via a bus to transfer information between the components of the device. The memory device may include, for example, one or more volatile and / or non-volatile memories. In other words, for example, the memory device may be an electronic storage device (e.g., a computer-readable storage medium) including gates that are configured to store data (e.g., bits) that can be retrieved by a machine (e.g., a computing device such as a processor). The memory device can be configured to store information, data, content, applications, instructions, etc. to enable the device 20 to perform various functions according to the example embodiments of the present invention. For example, the memory device can be configured to buffer input data for processing by the processor. Additionally or alternatively, the memory device can be configured to store instructions for execution by the processor.

[0106] As described above, the device 20 may be embodied by a computing device 10 configured to employ an example embodiment of the present invention. However, in some embodiments, the device may be embodied as a chip or chipset. In other words, the device may include one or more physical packages (e.g., chips) comprising materials, components, and / or wires on a structural assembly (e.g., a backplane). The structural assembly may provide physical strength, conservation of size, and / or limitation of electrical interactions for the component circuitry included thereon. Thus, in some cases, the device may be configured to implement embodiments of the present invention on a single chip or as a single "system on a chip." Thus, in some cases, a chip or chipset may constitute a device for performing one or more operations to provide the functionality described herein.

[0107] The processor 22 can be embodied in a variety of different ways. For example, the processor can be embodied as one or more of various hardware processing devices, such as a coprocessor, a microprocessor, a controller, a digital signal processor (DSP), a processing element with or without an attached DSP, or various other processing circuits, including integrated circuits, such as ASICs (application specific integrated circuits), FPGAs (field programmable gate arrays), microcontroller units (MCUs), hardware accelerators, special computer chips, etc. Thus, in some embodiments, the processor may include one or more processing cores configured to execute independently. A multi-core processor can implement multi-processing within a single physical package. Additionally or alternatively, the processor may include one or more processors configured in series via a bus to enable independent execution of instructions, pipelines, and / or multithreading.

[0108] In an exemplary embodiment, the processor 22 may be configured to execute instructions stored in the memory device 24 or otherwise accessible to the processor. Alternatively or in addition, the processor may be configured to execute hard-coded functions. Thus, whether configured by hardware or software methods, or by a combination of hardware or software methods, the processor may represent an entity (e.g., physically embodied in a circuit system) that is capable of performing operations according to embodiments of the present invention after being configured accordingly. Thus, for example, when the processor is embodied as an ASIC, FPGA, etc., the processor may be specifically configured hardware for performing the operations described herein. Alternatively, as another example, when the processor is embodied as an executor of software instructions, the instructions may specifically configure the processor to perform the algorithms and / or operations described herein when executing the instructions. However, in some cases, the processor may be a processor of a specific device that is configured to employ embodiments of the present invention by further configuring the processor according to instructions for performing the algorithms and / or operations described herein. The processor may, in particular, include a clock, an arithmetic logic unit (ALU), and logic gates configured to support the operations of the processor.

[0109] Meanwhile, the communication interface 26 may be any device, such as a device or circuit system embodied in hardware or a combination of hardware and software configured to receive and / or transmit data between the computing device 10 and the server 12. In this regard, the communication interface 26 may include, for example, an antenna (or multiple antennas) and supporting hardware and / or software for implementing wireless communication. Additionally or alternatively, the communication interface may include a circuit system for interacting with the antenna to cause a signal to be transmitted via the antenna or to process the reception of a signal received via the antenna. For example, the communication interface may be configured to wirelessly communicate with the head-mounted display 10, for example, via Wi-Fi, Bluetooth, or other wireless communication technologies. In some cases, the communication interface may alternatively or also support wired communication. Thus, for example, the communication interface may include a communication modem and / or other hardware / software for supporting communication via cable, digital subscriber line (DSL), universal serial bus (USB), or other mechanisms. For example, the communication interface may be configured to communicate with other components of the computing device via wired communication.

[0110] Figure 3 A data flow diagram illustrating an exemplary embodiment of the present invention is shown. In particular, Figure 3 The initiation of the UE-initiated PDU session establishment procedure and the subsequent SMF response are shown. For example, in some embodiments, the UE may initiate a UE-requested PDU session establishment procedure. If the UE requests to establish a new always-online PDU session, the UE should include an always-online PDU session requested information element (IE) and set the value of the IE to "always-online PDU session requested" or the like. Thus, as shown in 305, the UE 102 may provide a PDU session establishment request message to the SMF 110. Thus, also at 305, the SMF 110 receives a PDU session establishment request message from the UE 102. The PDU session establishment request message may include an always-online PDU session requested IE, wherein the always-online PDU session requested IE is set to a value such as "always-online PDU session requested".

[0111] After receiving the IE of the always-online PDU session requested in the PDU session establishment request message and setting it to a value such as "request always-online PDU session", the determination can be made based on, for example, a local policy or configuration in the SMF. Figure 3As shown in step 310, after receiving the PDU session establishment request message from the UE, the SMF may provide a PDU session establishment accept message to the UE. In some embodiments, for example, if the SMF determines that the requested PDU session needs to be established as an always-on PDU session, the SMF shall include the always-on PDU session indication IE in the PDU session establishment accept message and shall set the value to "always-on PDU session required". In some embodiments, for example, if the SMF determines that the requested PDU session should not be established as an always-on PDU session, and if the UE includes the IE requested for the always-on PDU session, the SMF shall include the always-on PDU session indication IE in the PDU session establishment accept message and shall set the value to "always-on PDU session not allowed". In some embodiments, for example, if the SMF determines that the requested PDU session should not be established as an always-on PDU session, and if the UE does not include the IE requested for the always-on PDU session, the SMF shall not include the always-on PDU session indication IE in the PDU session establishment accept message.

[0112] Thereafter, if the Always-On PDU Session Indication IE is included in the PDU SESSION SETUP ACCEPT message and the value is set to "Always-On PDU Session Required", the UE shall regard the established PDU Session as an Always-On PDU Session. However, if the Always-On PDU Session Indication IE is included in the PDU SESSION SETUP ACCEPT message but the value is set to "Always-On PDU Session Not Allowed", the UE shall not regard the established PDU Session as an Always-On PDU Session. If the UE does not receive the Always-On PDU Session Indication IE in the PDU SESSION SETUP ACCEPT message, the UE shall not regard the established PDU Session as an Always-On PDU Session.

[0113] Regarding the inter-system change from N1 mode to S1 mode, the UE and SMF shall maintain the always-on PDU session indication after the inter-system change from N1 mode to S1 mode. When the UE moves back to 5GS (i.e., inter-system change from S1 mode to N1 mode), the UE and SMF may use the always-on PDU session indication to determine whether the PDU session delivered from EPS is an always-on PDU session.

[0114] Regarding the inter-system change from S1 mode to N1 mode, after the inter-system change from S1 mode to N1 mode in 5GMM idle mode, the UE shall set the always-on PDU session indication to the always-on PDU session maintained in the UE, if any.

[0115] Figure 5 and Figure 6The present invention illustrates operations performed by devices, such as an SMF and a UE, respectively, to utilize a PDU session establishment procedure, and in particular to provide and / or utilize always-online as an attribute of a PDU session and to provide interworking aspects related to the always-online PDU session. That is, in another exemplary embodiment, a method, an apparatus, and / or a computer program product may be provided for providing a procedure for establishing a PDU session, and in particular for utilizing always-online as an attribute of a PDU session to determine whether to provide an always-online PDU session, and providing the always-online PDU session after determining to provide the always-online PDU session. Figure 5 is an example flow chart illustrating a method of operating an example device (e.g., device 200) embodied by, for example, SMF 110, performed in accordance with an embodiment of the present invention.

[0116] In an example embodiment, the device 20 includes means (e.g., processor 210, etc.) configured to receive a PDU session establishment request message from a UE. In some embodiments, the PDU session establishment request message may be configured to indicate a request to establish a new PDU session. In some embodiments, the PDU session establishment request message may include an IE set to a value indicating a request to establish a new always-on PDU session. See Figure 4 of block 405.

[0117] Subsequently, a determination may then be made as described above. Thus, the apparatus 200 includes means (e.g., the processor 210, etc.) configured to determine, based on local policy or configuration, whether the requested PDU session should be established as an always-on PDU session. Figure 4 Block 410 of . The determination may result in a determination that the requested PDU session should be established as an always-on PDU session, or alternatively, a determination that the requested PDU session should not be established as an always-on PDU session. Thus, the device 20 includes means (e.g., the processor 210, etc.) configured to, after determining that the requested PDU session should be established as an always-on PDU session, cause transmission of a PDU session establishment accept message, the PDU session establishment accept message including an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating that an always-on PDU session is required. See Figure 4 Block 415 of the apparatus 20 includes means (e.g., the processor 210, etc.) configured to, after determining that the requested PDU session should not be established as an always-on PDU session, cause transmission of a PDU session establishment accept message, the PDU session establishment accept message including an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating that "always-on PDU sessions are not allowed." See Figure 4 Block 420.

[0118] Since the Always-Online PDU Session Indication IE is set to one of "Always-Online PDU Session Required" or "Always-Online PDU Session Not Allowed", the UE is informed of the status of the newly established PDU session. The device 20 includes means (e.g., the processor 210, etc.) configured to cause the UE to regard the established PDU session as an Always-Online PDU Session if the Always-Online PDU Session Indication IE is included in the PDU Session Setup Accept message and the Always-Online PDU Session Indication IE is set to a value indicating "Always-Online PDU Session Required". See Figure 4 Block 425 of the apparatus 20 includes means (e.g., the processor 210, etc.) configured to cause the UE to not regard the established PDU session as an always-on PDU session if the always-on PDU session indication IE is included in the PDU session setup accept message and the always-on PDU session indication IE is set to a value indicating that “always-on PDU session is not allowed”. Figure 4 Block 430.

[0119] The apparatus 20 includes means (eg, a processor 210, etc.) configured to maintain an always-on PDU session indication at the UE and the SMF after an inter-system change from N1 mode to S1 mode. Figure 4 Block 435 of the apparatus 20 includes means (e.g., processor 210, etc.) configured to determine whether a PDU session transmitted from an evolved packet system (EPS) is an always-on PDU session based on an always-on PDU session indication after an inter-system change from S1 mode to N1 mode. Figure 4 of block 440.

[0120] Figure 5 1 is a flow chart depicting an exemplary embodiment for requesting an always-on PDU session. In particular, the UE may initiate a UE-requested PDU session establishment procedure. For example, in the case where the UE is configured to establish a new always-on PDU session, the UE should include an always-on PDU session requested information element (IE) and set the value of the IE to "request always-on PDU session". Figure 5 The operations performed by the device 200 to request an always-online PDU session using the always-online attribute IE of the PDU session are depicted in the flowchart of .

[0121] The apparatus 20 includes means (e.g., processor 210, etc.) configured to cause transmission of a protocol data unit (PDU) session establishment request message. In some embodiments, for example, those in which the UE is configured to require an always-on PDU session, the PDU session establishment request message may be configured to indicate a request to establish a new PDU session, such that the PDU session establishment request message includes an IE set to a value indicating a request to establish a new always-on PDU session. See Figure 5 Block 505.

[0122] After transmitting the PDU Session Establishment Request message, the determination may be made by, for example, the SMF. The device 20 includes means (e.g., the processor 210, etc.) configured to receive a PDU Session Establishment Accept message after determining that the requested PDU session should be established as an always-online PDU session, the PDU Session Establishment Accept message including an always-online PDU Session Indication IE, wherein the always-online PDU Session Indication IE is set to a value indicating "always-online PDU session required". See Figure 5 Block 510.

[0123] The device 20 may further include a device (e.g., processor 210, etc.) configured to receive a PDU session establishment accept message after, for example, the SMF determines that the requested PDU session should not be established as an always-on PDU session, the PDU session establishment accept message including the always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating that "always-on PDU session is not allowed". See Figure 5 Block 515.

[0124] The device 20 includes means (e.g., the processor 210, etc.) configured to treat the established PDU session as an always-on PDU session if the always-on PDU session indication IE is included in the PDU session establishment accept message and the always-on PDU session indication IE is set to a value indicating "always-on PDU session required". Figure 5 Block 520 of the apparatus 20 includes means (e.g., the processor 210, etc.) configured to not regard the established PDU session as an always-online PDU session if the always-online PDU session indication IE is included in the PDU session establishment accept message and the always-online PDU session indication IE is set to a value indicating that “always-online PDU session is not allowed”. Figure 5 Block 525.

[0125] Figure 6 A data flow diagram illustrating an exemplary embodiment of the present invention is shown. In particular, Figure 6The PDU Session Modification process is shown. For example, in some embodiments, for a PDN connection established when in S1 mode (i.e., the UE and SMF do not have any maintained always-on PDU session indications), and at the first inter-system change from S1 mode to N1 mode (e.g., Figure 6 After 605), in the following case: the UE operates in single registration mode in a network that does not support interworking without N26 and the UE requires the PDN connection to be an always-on PDU session in 5GS, the UE shall include the IE requested for always-on PDU session and set the value of the IE to "request always-on PDU session". Figure 6 of 610.

[0126] Subsequently, a determination may be made, for example at the SMF, as to whether the requested PDU Session is to be established as an always-on PDU Session. Once the determination is made, the SMF may, for example, provide a PDU Session Modification Command message to the UE. Figure 6 615. In particular, for a PDN connection established while in S1 mode, after the first inter-system change from S1 mode to N1 mode, if the network requested PDU session modification procedure is triggered by the UE requested PDU session modification procedure, and the SMF determines that the requested PDU session needs to be an always-on PDU session based on the local policy or configuration in the SMF and the always-on PDU session requested IE (if any) in the PDU session modification request message, the SMF shall include the always-on PDU session indication IE in the PDU session modification command message and set the value to "always-on PDU session required". Alternatively, for a PDN connection established while in S1 mode, after the first inter-system change from S1 mode to N1 mode, if the network requested PDU session modification procedure is triggered by the UE requested PDU session modification procedure, and the SMF determines based on the local policy or configuration in the SMF and the Always-on PDU Session Requested IE (if any) in the PDU Session Modification Request message that the requested PDU session should not be an Always-on PDU Session, and if the UE includes the Always-on PDU Session Requested IE, then the SMF shall include the Always-on PDU Session Indication IE in the PDU Session Modification Command message and set the value to "Always-on PDU Session Not Allowed".

[0127] In those embodiments where the network requested PDU session modification procedure is triggered by the UE requested PDU session modification procedure, for a PDN connection established while in S1 mode, after the first inter-system change from S1 mode to N1 mode, the SMF determines that the requested PDU session should not be an always-online PDU session based on the local policy or configuration in the SMF and the always-online PDU session requested IE (if any) in the PDU session modification request message, and the UE does not include the always-online PDU session requested IE, the SMF shall not include the always-online PDU session indication IE in the PDU session modification command message.

[0128] Thereafter, if the Always-On PDU Session Indication IE is included in the PDU Session Modify Command message and the value is set to "Always-On PDU Session Required", the UE shall regard the established PDU Session as an Always-On PDU Session. Whereas, if the Always-On PDU Session Indication IE is included in the PDU Session Modify Command message and the value is set to "Always-On PDU Session Not Allowed", the UE shall not regard the established PDU Session as an Always-On PDU Session. If the UE does not receive the Always-On PDU Session Indication IE in the PDU Session Modify Command message, the UE shall not regard the modified PDU Session as an Always-On PDU Session.

[0129] In some embodiments, for a PDN connection established while in S1 mode, after the first inter-system change from S1 mode to N1 mode, based on said local policy or configuration in the SMF, if the SMF determines that the requested PDU session needs to be an always-on PDU session, the SMF shall include the always-on PDU session indication IE in the PDU session modification command message and shall set the value to "always-on PDU session required".

[0130] For a PDN connection established in S1 mode, after the first inter-system change from S1 mode to N1 mode, based on the local policy or configuration in the SMF, if the SMF determines that the requested PDU Session should not be an always-on PDU Session, the SMF shall include the always-on PDU Session Indication IE in the PDU Session Modify Command message and shall set the value to "Always-on PDU Session not allowed". Otherwise, the SMF shall not include the always-on PDU Session Indication IE in the PDU Session Modify Command message.

[0131] Finally, if the Always-On PDU Session Indication IE is included in the PDU Session Modify Command message and the value is set to "Always-On PDU Session Required", the UE shall regard the PDU session as an Always-On PDU Session. However, if the Always-On PDU Session Indication IE is included in the PDU Session Modify Command message and the value is set to "Always-On PDU Session Not Allowed", the UE shall not regard the PDU session as an Always-On PDU Session. In this case, the UE may be configured to ignore any indication from upper layers regarding Always-On PDU Sessions and notify the upper layers to ignore indications regarding Always-On PDU Sessions.

[0132] Figure 7 and Figure 8 Operations performed by devices, such as an SMF and a UE, respectively, are shown to provide a modification procedure for a PDN connection established when in S1 mode. That is, in another exemplary embodiment, a method, apparatus, and / or computer program product may be provided for providing a modification procedure for a PDN connection established when in S1 mode. Figure 7 is an example flow chart illustrating a method of operating an example device (e.g., device 200) embodied by, for example, SMF 110, performed in accordance with an embodiment of the present invention.

[0133] In an example embodiment, the apparatus 200 includes means (e.g., the processor 210, etc.) configured to receive a PDU session modification request message from a UE, the PDU session modification request message being configured to indicate a request to modify a PDU session corresponding to a PDN connection established when in the S1 mode after a first inter-system change from the S1 mode to the N1 mode, the PDU session modification request message including an IE set to a value indicating a request that the PDU session be an always-on PDU session, or the PDU session modification request message not including an IE requested for an always-on PDU session. See Figure 7 In an example embodiment, the apparatus 200 includes means (e.g., the processor 210, etc.) configured to determine whether the requested PDU session should be an always-online PDU session based on a local policy or configuration and based on the IE that the always-online PDU session would request if the IE requested by the always-online PDU session is available. Figure 7 Block 710.

[0134] In an example embodiment, the apparatus 200 includes means (e.g., the processor 210, etc.) configured to, upon determining that the requested PDU session should be an always-on PDU session, cause transmission of a PDU session modification command message, the PDU session modification command message including an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating that an always-on PDU session is required. Figure 7 Block 715. The device 200 may also include a device (e.g., processor 210, etc.) configured to, after determining that the requested PDU session should not be an always-online PDU session, cause transmission of a PDU session modification command message, the PDU session modification command message including the always-online PDU session indication IE if the UE includes the IE requested for the always-online PDU session in the PDU session establishment request message; or the PDU session modification command message does not include the always-online PDU session indication IE if the UE does not include the IE requested for the always-online PDU session in the PDU session establishment request message. See Figure 7 Block 720.

[0135] Subsequently, in an example embodiment, the apparatus 200 includes means (e.g., the processor 210, etc.) configured to, in the following cases: the always-online PDU session indication IE is not included in the PDU session modification command message, or the always-online PDU session indication IE is included in the PDU session modification command message and the always-online PDU session indication IE is set to indicate "always-online PDU session required", cause the UE to regard the PDU session as an always-online PDU session. See Figure 7 The apparatus 200 may then further include means (e.g., the processor 210, etc.) configured to cause the UE to not regard the PDU session as an always-online PDU session if the always-online PDU session indication IE is included in the PDU session modification command message and the always-online PDU session indication IE is set to a value indicating that “always-online PDU session is not allowed”. Figure 7 Block 730.

[0136] In an example embodiment, the apparatus 200 includes a device (e.g., a processor 210, etc.) configured to: determine whether the requested PDU session needs to be an always-on PDU session based on the local policy or configuration in the SMF after the inter-system change from the S1 mode to the N1 mode; and after determining that the requested PDU session needs to be an always-on PDU session, set the always-on PDU session indication IE included in the PDU session modification command message to a value indicating "always-on PDU session required". Figure 7 Block 735.

[0137] In an example embodiment, the apparatus 200 includes a device (e.g., a processor 210, etc.) configured to: determine whether the requested PDU session needs to be an always-on PDU session based on the local policy or configuration in the SMF after the inter-system change from the S1 mode to the N1 mode; and after determining that the requested PDU session does not need to be an always-on PDU session, set the always-on PDU session indication IE included in the PDU session modification command message to a value indicating that "always-on PDU session is not allowed". See Figure 7 Block 740.

[0138] As mentioned above, Figure 8 Operations performed by a device, e.g., embodied by a UE, regarding a modification procedure for a PDN connection established while in S1 mode are shown. That is, in another exemplary embodiment, a method, device, and / or computer program product may be provided for implementing a modification procedure for a PDN connection established while in S1 mode. Figure 8 is an example flow chart illustrating a method of operating an example device (e.g., device 200) embodied, for example, by UE 102, performed in accordance with an embodiment of the present invention.

[0139] In an example embodiment, the apparatus 200 includes means (e.g., the processor 210, etc.) configured to cause transmission of a PDU session modification request message, the PDU session modification request message being configured to indicate a request to modify a PDU session corresponding to a PDN connection established while in S1 mode after a first inter-system change from S1 mode to N1 mode. In some embodiments, the PDU session modification request message may include an IE whose value is set to indicate a request for the PDU session to be an always-on PDU session, or the PDU session modification request message may not include an IE requested for an always-on PDU session. See Figure 8 Block 805.

[0140] Subsequently, a determination may be made at the SMF as to whether the requested PDU Session will be an always-on PDU Session. Once the determination is made, the SMF may, for example, provide a PDU Session Modification Command message to the UE. In an example embodiment, the apparatus 200 includes means (e.g., the processor 210, etc.) configured to receive a PDU Session Modification Command message after determining that the requested PDU Session should be an always-on PDU Session, the PDU Session Modification Command message including an always-on PDU Session Indication IE, wherein the always-on PDU Session Indication IE is set to a value indicating that an always-on PDU Session is required. See Figure 8 Block 810.

[0141] The device 200 may also include a device (e.g., processor 210, etc.) configured to receive a PDU session modification command message after determining that the requested PDU session should not be an always-online PDU session, if the UE includes the IE requested by the always-online PDU session in the PDU session modification request message, then the PDU session modification command message includes the always-online PDU session indication IE, wherein the always-online PDU session indication IE is set to a value indicating that "always-online PDU session is not allowed", or if the UE does not include the IE requested by the always-online PDU session in the PDU session modification request message, then the PDU session modification command message does not include the always-online PDU session indication IE. See. Figure 8 Block 815.

[0142] Thereafter, in an example embodiment, the apparatus 200 includes means (e.g., the processor 210, etc.) configured to treat the PDU session as an always-online PDU session if the always-online PDU session indication IE is included in the PDU session modification command message and the always-online PDU session indication IE is set to a value indicating that "always-online PDU session is required". Figure 8 Block 820.

[0143] The device 200 may further include means (e.g., the processor 210, etc.) configured to not regard the PDU session as an always-online PDU session if the always-online PDU session indication IE is included in the PDU session modification command message and the always-online PDU session indication IE is set to a value indicating that "always-online PDU session is not allowed". Figure 8 Block 825.

[0144] As mentioned above, Figure 4 、 Figure 5 、 Figure 7 and Figure 8Flowcharts of devices, methods, and computer program products according to example embodiments of the present invention are provided. It will be understood that each block of the flowchart and combinations of blocks in the flowchart can be implemented in various ways, such as hardware, firmware, a processor, circuitry, and / or other devices associated with the execution of software comprising one or more computer program instructions. For example, one or more of the above-described processes can be embodied by computer program instructions. In this regard, the computer program instructions embodying the above-described processes can be stored by a memory device of a device employing an embodiment of the present invention and executed by a processor of the device. It will be understood that any such computer program instructions can be loaded onto a computer or other programmable device (e.g., hardware) to produce a machine such that the resulting computer or other programmable device performs the functions specified in the flowchart blocks. These computer program instructions can also be stored in a computer-readable memory that can direct the computer or other programmable device to operate in a specific manner such that the instructions stored in the computer-readable memory produce an article of manufacture, the execution of which implements the functions specified in the flowchart blocks. The computer program instructions can also be loaded onto a computer or other programmable device to cause a series of operations to be performed on the computer or other programmable device, thereby producing a computer-implemented process such that the instructions executed on the computer or other programmable device provide operations for performing the functions specified in the flowchart blocks.

[0145] A computer program product is therefore defined as follows: computer program instructions (e.g. computer readable program code portions) are stored by at least one non-transitory computer readable storage medium, wherein the computer program instructions (e.g. computer readable program code portions) are configured to perform the functions described above when executed, e.g. in combination with Figure 4 、 Figure 5 、 Figure 7 and Figure 8 In other embodiments, the computer program instructions (e.g., computer readable program code portions) need not be stored or otherwise embodied by a non-transitory computer readable storage medium, but may be embodied by a transitory medium having computer program instructions (e.g., computer readable program code portions) that are still configured to perform the functions described above when executed.

[0146] Therefore, the blocks of the flowchart support combinations of means for performing the specified functions and combinations of operations for performing the specified functions. It will also be understood that one or more blocks of the flowchart and combinations of blocks in the flowchart can be implemented by a computer system based on special-purpose hardware that performs the specified functions or a combination of special-purpose hardware and computer instructions.

[0147] In some embodiments, some of the above operations may be modified or further amplified. In addition, in some embodiments, additional optional operations may be included. Modifications, additions, or amplifications to the above operations may be performed in any order and in any combination.

[0148] Benefiting from the teachings presented in the foregoing description and the associated drawings, many modifications and other embodiments of the present invention set forth herein will come to mind to those skilled in the art associated with these inventions. Therefore, it should be understood that the present invention is not limited to the specific embodiments disclosed, and modifications and other embodiments are intended to be included within the scope of the appended claims. In addition, although the foregoing description and the associated drawings have described example embodiments in the context of certain example combinations of elements and / or functions, it should be understood that different combinations of elements and / or functions may be provided by alternative embodiments without departing from the scope of the appended claims. In this regard, for example, as set forth in some of the appended claims, combinations of elements and / or functions that are different from the combinations of elements and / or functions explicitly described above are also contemplated. Although specific terms are employed herein, these terms are used only in a general and descriptive sense and not for purposes of limitation.

Claims

1. An apparatus for performing a service request process, the apparatus comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code being configured to, together with the processor, cause the apparatus to at least: receiving a protocol data unit (PDU) session establishment request message from a user equipment (UE), the PDU session establishment request message being configured to indicate a request to establish a PDU session, the PDU session establishment request message including an always-on PDU session requested information element (IE), the always-on PDU session requested IE being set to a value indicating a request to establish the PDU session as an always-on PDU session; and In a case where the always-on PDU session requested IE is set to the value indicating the request to establish the always-on PDU session, determining whether to establish the requested PDU session as an always-on PDU session based on a local policy or configuration.

2. The apparatus of claim 1 , wherein the at least one memory and the computer program code are configured to, with the processor, cause the apparatus to at least: After determining to establish the requested PDU session as an always-on PDU session, causing a PDU session establishment accept message to be transmitted to the UE, the PDU session establishment accept message including an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating that "always-on PDU session is required".

3. The apparatus of claim 1 , wherein the at least one memory and the computer program code are configured to, with the processor, cause the apparatus to at least: After determining not to establish the requested PDU session as an always-on PDU session, causing a PDU session establishment accept message to be transmitted to the UE, If the UE includes the IE requested by the always-online PDU session in the PDU session establishment request message, the PDU session establishment accept message includes the always-online PDU session indication IE, wherein the always-online PDU session indication IE is set to a value indicating that "always-online PDU session is not allowed".

4. The apparatus of claim 1 , wherein the at least one memory and the computer program code are configured to, with the processor, cause the apparatus to at least: After the intersystem change from N1 mode to S1 mode, the always-on PDU session indication is maintained.

5. The apparatus of claim 4, wherein the at least one memory and the computer program code are configured to, with the processor, cause the apparatus to at least: After an intersystem change from the S1 mode to the N1 mode, determining whether the PDU session transmitted from an Evolved Packetization System (EPS) is an always-on PDU session based on the always-on PDU session indication.

6. A method for performing a service request process, the method comprising: receiving a protocol data unit (PDU) session establishment request message from a user equipment (UE), the PDU session establishment request message being configured to indicate a request to establish a PDU session, the PDU session establishment request message including an always-on PDU session requested information element (IE), the always-on PDU session requested IE being set to a value indicating a request to establish the PDU session as an always-on PDU session; as well as In a case where the IE requested for the always-on PDU session is set to the value indicating the request to establish the PDU session as an always-on PDU session, determining whether to establish the requested PDU session as an always-on PDU session is determined based on a local policy or configuration.

7. An apparatus comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the processor, cause the apparatus to at least: including an always-on protocol data unit (PDU) session requested information element (IE) in a PDU session establishment request message, the PDU session establishment request message being configured to indicate a request to establish a PDU session; Setting the always-online PDU session requested IE in the PDU session establishment request message to a value, wherein the value indicates a request to establish the PDU session as an always-online PDU session; causing transmission of the PDU session establishment request message; as well as A PDU session establishment accept message is received, wherein the PDU session establishment accept message includes an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating "always-on PDU session required" or to a value indicating "always-on PDU session not allowed".

8. The apparatus of claim 7, wherein the at least one memory and the computer program code are configured to, with the processor, cause the apparatus to at least: In a case where the always-online PDU session indication IE is included in the PDU session establishment accept message and the always-online PDU session indication IE is set to a value indicating “always-online PDU session required”, the established PDU session is regarded as an always-online PDU session.

9. The apparatus of claim 7, wherein the at least one memory and the computer program code are configured to, with the processor, cause the apparatus to at least: In a case where the always-online PDU session indication IE is included in the PDU session establishment accept message and the always-online PDU session indication IE is set to a value indicating that “always-online PDU session is not allowed”, the established PDU session is not regarded as an always-online PDU session.

10. A method comprising: including an always-on protocol data unit (PDU) session requested information element (IE) in a PDU session establishment request message, the PDU session establishment request message being configured to indicate a request to establish a PDU session; Setting the always-online PDU session requested IE in the PDU session establishment request message to a value, wherein the value indicates a request to establish the PDU session as an always-online PDU session; causing transmission of the PDU session establishment request message; as well as A PDU session establishment accept message is received, wherein the PDU session establishment accept message includes an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating "always-on PDU session required" or to a value indicating "always-on PDU session not allowed".

11. An apparatus for performing a service request process, the apparatus comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the processor, cause the apparatus to at least: receiving a protocol data unit (PDU) session establishment request message from a user equipment (UE), the PDU session establishment request message being configured to indicate a request to establish a PDU session, the PDU session establishment request message including an always-on PDU session requested information element (IE), the always-on PDU session requested IE being set to a value indicating a request to establish the PDU session as an always-on PDU session; determining, in a case where the always-on PDU session requested IE is set to the value indicating the request to establish the always-on PDU session, whether to establish the requested PDU session as an always-on PDU session based on a local policy or configuration; Establishing the requested PDU session as an always-on PDU session in N1 mode; as well as In case an inter-system change from the N1 mode to the S1 mode is made, the always-online PDU session indication associated with the always-online PDU session is maintained.

12. The apparatus of claim 11 , wherein the at least one memory and the computer program code are configured to, with the processor, cause the apparatus to at least: After determining to establish the requested PDU session as an always-on PDU session, causing a PDU session establishment accept message to be transmitted to the UE, the PDU session establishment accept message including an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating that "always-on PDU session is required".

13. The apparatus of claim 11 , wherein the at least one memory and the computer program code are configured to, with the processor, cause the apparatus to at least: After determining not to establish the requested PDU session as an always-on PDU session, causing a PDU session establishment accept message to be transmitted to the UE, If the UE includes the IE requested by the always-online PDU session in the PDU session establishment request message, the PDU session establishment accept message includes the always-online PDU session indication IE, wherein the always-online PDU session indication IE is set to a value indicating that "always-online PDU session is not allowed".

14. The apparatus of claim 11 , wherein the at least one memory and the computer program code are configured to, with the processor, cause the apparatus to at least: After the inter-system change from S1 mode to N1 mode, it is determined whether the PDU session transmitted from an Evolved Packetization System (EPS) is an always-on PDU session based on the always-on PDU session indication.

15. A method for performing a service request process, the method comprising: receiving a protocol data unit (PDU) session establishment request message from a user equipment (UE), the PDU session establishment request message being configured to indicate a request to establish a PDU session, the PDU session establishment request message including an always-on PDU session requested information element (IE), the always-on PDU session requested IE being set to a value indicating a request to establish the PDU session as an always-on PDU session; as well as determining, based on a local policy or configuration, whether to establish the requested PDU session as an always-on PDU session, if the always-on PDU session requested IE is set to the value indicating the request to establish the PDU session as an always-on PDU session; Establishing the requested PDU session as an always-on PDU session in N1 mode; as well as In case an inter-system change from the N1 mode to the S1 mode is made, the always-online PDU session indication associated with the always-online PDU session is maintained.

16. The method according to claim 15, further comprising: After determining to establish the requested PDU session as an always-on PDU session, causing a PDU session establishment accept message to be transmitted to the UE, the PDU session establishment accept message including an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating that "always-on PDU session is required".

17. The method according to claim 15, further comprising: After determining not to establish the requested PDU session as an always-on PDU session, causing a PDU session establishment accept message to be transmitted to the UE, If the UE includes the IE requested by the always-online PDU session in the PDU session establishment request message, the PDU session establishment accept message includes the always-online PDU session indication IE, wherein the always-online PDU session indication IE is set to a value indicating that "always-online PDU session is not allowed".

18. The method according to claim 15, further comprising: After the inter-system change from S1 mode to N1 mode, it is determined whether the PDU session transmitted from an Evolved Packetization System (EPS) is an always-on PDU session based on the always-on PDU session indication.

19. An apparatus comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the processor, cause the apparatus to at least: including an always-on protocol data unit (PDU) session requested information element (IE) in a PDU session establishment request message, the PDU session establishment request message being configured to indicate a request to establish a PDU session; Setting the always-online PDU session requested IE in the PDU session establishment request message to a value, wherein the value indicates a request to establish the PDU session as an always-online PDU session; causing transmission of the PDU session establishment request message; A PDU session establishment accept message is received, the PDU session establishment accept message including an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating "always-on PDU session required" or to a value indicating "always-on PDU session not allowed", wherein in a case where the requested PDU session is established as an always-on PDU session in N1 mode, the always-on PDU session indication IE is configured to cause the always-on PDU session indication IE associated with the always-on PDU session to be maintained after an inter-system change from N1 mode to S1 mode.

20. The apparatus of claim 19, wherein the at least one memory and the computer program code are configured to, with the processor, cause the apparatus to at least: In a case where the always-online PDU session indication IE is included in the PDU session establishment accept message and the always-online PDU session indication IE is set to a value indicating “always-online PDU session required”, the established PDU session is regarded as an always-online PDU session.

21. The apparatus of claim 19, wherein the at least one memory and the computer program code are configured to, with the processor, cause the apparatus to at least: In a case where the always-online PDU session indication IE is included in the PDU session establishment accept message and the always-online PDU session indication IE is set to a value indicating that “always-online PDU session is not allowed”, the established PDU session is not regarded as an always-online PDU session.

22. A method comprising: including an always-on protocol data unit (PDU) session requested information element (IE) in a PDU session establishment request message, the PDU session establishment request message being configured to indicate a request to establish a PDU session; Setting the always-online PDU session requested IE in the PDU session establishment request message to a value, wherein the value indicates a request to establish the PDU session as an always-online PDU session; causing transmission of the PDU session establishment request message; as well as A PDU session establishment accept message is received, the PDU session establishment accept message including an always-on PDU session indication IE, wherein the always-on PDU session indication IE is set to a value indicating "always-on PDU session required" or to a value indicating "always-on PDU session not allowed", wherein in a case where the requested PDU session is established as an always-on PDU session in N1 mode, the always-on PDU session indication IE is configured to cause the always-on PDU session indication IE associated with the always-on PDU session to be maintained after an inter-system change from N1 mode to S1 mode.

23. The method according to claim 22, further comprising: In a case where the always-online PDU session indication IE is included in the PDU session establishment accept message and the always-online PDU session indication IE is set to a value indicating “always-online PDU session required”, the established PDU session is regarded as an always-online PDU session.

24. The method according to claim 22, further comprising: In a case where the always-online PDU session indication IE is included in the PDU session establishment accept message and the always-online PDU session indication IE is set to a value indicating that “always-online PDU session is not allowed”, the established PDU session is not regarded as an always-online PDU session.

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