Patent Description:
In the telecommunications arena, there is a constant evolution ongoing in order to provide efficient and reliable solutions for utilizing wireless communication networks. Each new generation has it owns technical challenges for handling the different situations and processes that is needed to connect and service devices connected to the wireless network. This is especially true for cellular telecommunications networks.

Cellular telecommunication networks comprise on a high level an access infrastructure and a core infrastructure. The access infrastructure provides radio access for connecting devices and handles the connectivity of these devices. The core infrastructure provide authentication, billing, quality of service (QoS) handling, and similar user/device management features. Furthermore, the core network also provides access to external networks such as for instance Internet access. It should be noted that the connecting devices are often denoted user equipment UE but the devices do not necessarily need a user but can be any type of device connecting to the network, i.e., a device capable of wireless communication with a radio access network node, the UE may for example be a smartphone, laptop, PC, utility device, vehicle, a smart sensor, etc. With the advent of Internet of Things (IoT) many different types of devices, functions and solutions are being rolled out that involve human interaction or as standalone devices serving different solutions or functions.

The Third Generation Partnership Project (3GPP) has begun work on the development and design of the next generation mobile communications system (a. , the <NUM> mobile communication system or the Next Generation (NG) system or simply "<NUM>" or "NG" for short). 3GPP is currently in the process of specifying the <NUM> radio interface called New Radio (NR) or "G-UTRA" as well as a Next Generation Packet Core Network (NG-CN or NGC).

A user equipment (UE) needs to register with a network in order to receive services which require registration. A registration procedure is utilized in the following situations: (<NUM>) when the UE initially registers to a <NUM> system; (<NUM>) when the UE initiates a registration procedure due to mobility, e.g. when the UE changes to a new Tracking Area (TA) in idle mode; (<NUM>) when the UE performs a periodic update due to expiration of a predefined time period of inactivity, etc. During an initial registration a Mobile Equipment (ME) Identity is obtained from the UE. An Access and Mobility Management function (AMF) operator may check the ME Identity with an EIR. The AMF then passes the ME Identity (IMEISV) to a Unified Data Management (UDM), a Session Management function (SMF) and a Policy Control function (PCF). The AMF is also known as the Mobility Management function (MMF), accordingly the AMF and the MMF are equivalent.

<NPL>) discloses registration procedures. A UE needs to register with the network to receive services that require registration. The registration procedure is used e.g. when the UE needs to initially register to the <NUM> system, upon mobility procedure when the UE changes to a new Tracking area (TA) in idle mode and when the UE performs a periodic update (due to a predefined time period of inactivity), etc..

<NPL>) discloses a PDU session establishment procedure requested by the UE.

At registration of a user equipment, UE, to a <NUM> Core Network (CN) it is not possible for the access and mobility management function, AMF, to know to setup or initiate user plane (UP) resources required for a particular Protocol Data Unit, PDU, session in which the UE has UP data to transmit. This disclosure addresses this issue.

For example, the UE includes information in a registration request message (e.g. Attach Request message, Tracking Area Update (TAU), Registration Request, or similar) regarding which PDU session(s) require(s) UP resources (e.g. Data Radio Bearers (DBRs) on a radio interface and related UP tunnels between network functions in the network). The AMF receives the registration request message transmitted by the UE which includes the information regarding which PDU session(s) requires the UP resources. The AMF requests the establishment of the UP resources, in accordance with the information regarding which PDU session(s) requires the UP resources in the registration request message transmitted by the UE. In response to the request for the establishment of the UP resources, a Radio Access Network (RAN) and SMF(s) allocate the UP resources accordingly.

An advantage provided by embodiments disclosed herein is that the network can configure the UP resources to enable the transfer of UP data for PDU session(s) indicated in a registration request message transmitted by a UE.

As mentioned above, user equipment (UE) <NUM> needs to register with the network to receive services that require registration. Referring now to <FIG> illustrates an exemplary <NUM> communication system <NUM>. The <NUM> communication system <NUM> illustrates a point to point reference point representation. In <FIG> some nodes and functions of the network are shown. A user equipment (UE) <NUM> connects to the network via a radio access network node (RAN) <NUM>. The RAN may be a for instance a base station, NodeB, or an eNodeB. It should be noted that the UE may be a mobile phone, for instance a smart phone, or some other type of unit with wireless communication capabilities, such as Internet of Thing (IoT) devices, Machine-to-machine devices, vehicles, sensors, computers, laptops, and so on. The RAN <NUM> is in turn connected to a core network comprising a User Plane function (UPF) <NUM>, an Access and Mobility Management function (AMF) <NUM>, a Session Management function (SMF) <NUM>, a Policy Control function (PCF) <NUM>. Furthermore, the network may comprise an Authentication Server Function /AUSF) <NUM>, a Unified Data Management node (UDM) <NUM>, an application function (AF) <NUM>, and connecting to an external data network (DN) <NUM>. These nodes/functions are interconnected with different interfaces NG1-NG15 as shown in <FIG>, it should be noted that interfaces may also be denoted with N1 to N15.

It should be noted that all nodes and functions may be physically located as separate nodes or partly incorporated into different nodes together with other nodes/functions but for illustrative purposes shown as separate entities.

The registration procedure is utilized in the following situations: (<NUM>) when the UE <NUM> initially registers to a <NUM> system; (<NUM>) when the UE <NUM> initiates a registration procedure due to mobility, e.g. when the UE <NUM> changes to a new registration area (e.g. a new Tracking Area (TA)) in idle mode; (<NUM>) when the UE <NUM> performs a periodic update due to expiration of a predefined time period of inactivity, etc..

During an initial registration a Mobile Equipment (ME) Identity is obtained from the UE <NUM>. An Access and Mobility Management function (AMF) <NUM> operator may check the ME Identity with an EIR. The AMF <NUM> then passes the ME Identity (IMEISV) to a Unified Data.

Management (UDM), a Session Management function (SMF) <NUM> and a Policy Control function (PCF).

<FIG> is a message flow diagram illustrating a UE registration process <NUM>, according to one embodiment.

In step <NUM>, the UE <NUM> transmits a registration request message to the RAN <NUM>. In an embodiment, the registration request message may comprise: a registration type identifier (ID) for identifying a registration type, a UE ID (e.g., a Permanent ID or a Temporary ID), security parameters, network slice selection assistance information (NSSAI), UE 5GCN Capability information, PDU session status information, and Radio Resource Control (RRC) parameters indicating Permanent ID or the Temporary ID, the Selected Network and NSSAI. The registration type ID indicates whether the UE <NUM> wants to perform an "initial registration" (i.e. the UE <NUM> is in non-registered state), a "mobility registration" (i.e. the UE <NUM> is in registered state and initiates a registration due to mobility) or a "periodic registration" (i.e. the UE <NUM> is in registered state and initiates a registration due to the periodic update timer expired). Advantageously, the registration request message may further include information identifying one or more Protocol Data Unit (PDU) sessions that require user plane (UP) resources, such as Data Radio Bearer(s) and tunnels between the UP function (UPF) and RAN. In one embodiment, the UE <NUM> marks the PDU session(s) which requires the establishment of UP resources with an Active flag in the registration request message. In a claimed embodiment, the marked PDU session(s) require the establishment of the UP resources because the UE <NUM> has UP data to transmit to the network. The registration request message includes a first ordered set of N bits (i.e., a "bitmap")), where each one of the N bits corresponds to a different one of N possible PDU sessions that could require UP resources (e.g., the first bit in the string corresponds to a first PDU session, the second bit in the string corresponds to a second PDU session, etc.). In some embodiments, N is equal to the total number of PDU sessions that are deemed active by the UE (e.g., N=<NUM>), whereas in other embodiments N is equal to the total number of possible active PDU sessions in the UE (e.g., N=<NUM>). The value of each bit in the bit string indicates whether the PDU session corresponding to the bit requires UP resources (e.g. if bit n is set to a value of <NUM>, then the PDU session corresponding to this bit requires UP resources, but if the bit n is set to a value of <NUM>, then the corresponding PDU session does not require UP resources). In this way, the UE can signal to the network the identity of the PDU session that require UP resources.

Further, the registration request message may also include information (e.g. a flag) indicating that the UE <NUM> is requesting "Follow-On" - that is, the UE is requesting the network to maintain the signaling connection with the UE after the registration procedure is completed because, for example, the UE has additional messages (e.g., a PDU session establishment message) to send to the network.

In step <NUM>, if the registration request message includes an ID (Permanent or Temporary) that does not indicate a valid AMF, the RAN <NUM> selects an AMF <NUM> based on Radio Access Technology (RAT) and NSSAI, if available.

In step <NUM>, the RAN <NUM> transmits the registration request message to the AMF <NUM>. In an embodiment, the registration request message transmitted to the AMF <NUM> further comprises: Location Information, Cell Identity, and RAT type. The Location Information, Cell Identity and RAT type relates to the cell in which the UE is located.

In step <NUM>, if the registration request message includes the UE's Temporary ID and the serving AMF <NUM> has changed since the last registration, the AMF <NUM> may transmit an Information Request to the old AMF. The Information Request includes the complete registration request message IE in order to request the UE's Permanent ID and Mobility Management (MM) Context.

In step <NUM>, in response to the Information Request transmitted by the AMF <NUM>, the old AMF responds with an Information Response. The Information Response comprises the Permanent ID, the MM Context, and the SMF information. In some embodiments, the old AMF has stored information regarding active PDU sessions. If the old AMF has stored information about active PDU sessions, the old AMF includes SMF information comprising SMF identities and corresponding PDU session identities in the Information Response so that the AMF <NUM> can map PDU sessions to SMFs.

In step <NUM>, if the Permanent ID is not provided by the UE <NUM> nor retrieved from the old AMF in the Information Response, an Identity Request procedure is initiated by the AMF <NUM> transmitting an Identity Request message to the UE <NUM>.

In step <NUM>, in response to the Identity Request message, the UE <NUM> responds to the AMF <NUM> with an Identity Response message including the Permanent ID.

In step <NUM>, the AMF <NUM> selects an AUSF if the registration request message is not sent with integrity protection or the integrity protection is indicated as failed based on the Permanent ID contained in the Information Response (step <NUM>).

In step <NUM>, if the AMF <NUM> selects the AUSF because the registration request message is not sent with integrity protection or the integrity protection is indicated as failed, the AUSF initiates authentication of the UE <NUM> and NAS security functions. Once security for the registration request message is established, the AMF <NUM> may fetch IMEI from the UE <NUM>.

In step <NUM>, the AMF <NUM> transmits an Identity Request to the UE <NUM> to retrieve the UE's ME identity if the ME identity is not provided by the UE <NUM> in the registration request message nor retrieved from the old AMF in the Information Response.

In step <NUM>, in some embodiments, the AMF initiates an ME identity check.

In step 11a, the AMF <NUM> sends a request (e.g., N11 Request) to SMF <NUM>. If the AMF <NUM> is changed, the AMF <NUM> notifies each SMF <NUM> of the new AMF <NUM> serving the UE <NUM> (i.e., the AMF <NUM> sends the request to each SMF). The new AMF <NUM> verifies the PDU session status received from the UE <NUM> with the SMF information received from the old AMF. If the AMF <NUM> has not changed, the AMF <NUM> verifies the PDU session status received from the UE <NUM> with the available SMF information. After the AMF <NUM> determines the active PDU sessions in the UE <NUM>, the AMF <NUM> releases any network resources related to PDU sessions that are not active in the UE <NUM>.

Additionally, if the registration request message indicates that one or more PDU sessions require UP resources, then, for each such PDU session, the AMF <NUM> transmits to the SMF responsible for handling the PDU session a UP resource request for causing the SMF to establish UP resources for the PDU session. For example, if the registration request message indicates that a PDU session being handled by SMF <NUM> requires UP resources, the request sent to SMF <NUM> in step 11a will further includes the UP resource request.

In step 11b, in response to the UP resource request, the SMF <NUM> transmits a UP resource response (e.g., N11 Response). In some embodiments, the SMF <NUM> decides to trigger a UPF relocation. In some embodiments, the SMF <NUM> provides the SM information (e.g., N2 SM information) in the UP resource response (e.g., N11 Response). The SM information may include quality-of-service (QoS) service information and tunnel endpoint information for establishing a tunnel between the radio access network (RAN) and UPF. In some embodiments, the SMF provides the SM information in the response only if the AMF specifically requested it in the request.

In step <NUM>, in some embodiments, the AMF <NUM> selects a UDM based on the UE's <NUM> Permanent ID.

In step <NUM>, the AMF <NUM> initiates an Update Location procedure if: (<NUM>) the AMF <NUM> has changed since the last registration; (<NUM>) there is no valid subscription context for the UE <NUM> in the AMF <NUM>; or (<NUM>) the UE <NUM> provides a Permanent ID which does not refer to a valid context in the AMF <NUM>. When the Update Location procedure is initiated, the UDM initiates Cancel Location to the old AMF, if available. In response to the Cancel Location, the old AMF removes the associated MM context and notifies all possibly associated SMF(s). In some embodiments, interactions between the UDM and the PCF includes mobility restriction related information.

In step <NUM>, in some embodiments, the AMF <NUM> selects the PCF based on the UE's <NUM> Permanent ID.

In step <NUM>, in some embodiments, the AMF <NUM> transmits a UE Context Establishment Request to the PCF to apply operator policies for the UE <NUM>.

In step <NUM>, the PCF responds to the UE Context Establishment Request with a UE Context Establishment Acknowledged to the AMF <NUM>.

In step <NUM>, in some embodiments, the old AMF transmits a UE Context Termination Request to the PCF.

In step <NUM>, the PCF responds to the UE Context Termination Request with a UE Context Termination Acknowledged to the old AMF.

In step <NUM>, the AMF <NUM> transmits a UE Context setup (Access Stratum (AS) Security Context information) to the RAN <NUM>. If in step 11b the AMF receives the SM information from SMF <NUM>, then this SM information and an N2 PDU Session Request (Quality of Service (QoS), tunnel information, etc.) is included in the UE Context setup.

The AMF <NUM> validates the UE's <NUM> presence in the (new) location and if all checks are successful and the UE marked a PDU session as requiring UP resources or requested Follow-On, then the connection is to be maintained and the AMF requests RAN to set up a secure connection to the UE by providing Access Stratum (AS) security context information in the UE Context Setup message sent to the RAN.

In some embodiments, the AMF <NUM> rejects the registration request message with an appropriate reject cause if the UE is not allowed to register in the current location.

In step 19a, if the UE Context setup request includes a PDU Session Request, the RAN <NUM> performs RRC Connection Reconfiguration with the UE <NUM> in order to establish the default radio bearer (DRB) for the PDU Session(s) request received in step <NUM>.

In step <NUM>, the AMF <NUM> sends a Registration Accept message to the UE <NUM> indicating that the registration request message has been accepted. In an embodiment, the Registration Accept message comprises: Temporary ID, Registration area. Mobility restrictions, and PDU session status. The AMF <NUM> indicates the PDU session status to the UE <NUM>. Accordingly, the UE removes any internal resources related to PDU sessions that are not marked active in the received PDU session status. If the PDU session status information was in the registration request message, the AMF <NUM> indicates the corresponding PDU session status to the UE <NUM>. In some embodiments, the Registration Accept message includes the Temporary ID if the AMF <NUM> allocates a new Temporary ID for the UE <NUM>. In some embodiments, the Registration Accept message includes Mobility restrictions if mobility restrictions apply to the UE <NUM>.

In step <NUM>, in response to the Registration Accept message, the UE <NUM> transmits a Registration Complete message to the AMF <NUM>. If a new Temporary ID is included in the Registration Accept message, the Registration Complete message acknowledges to the AMF <NUM> that the new Temporary ID is assigned.

<FIG> is a flow chart illustrating a process <NUM>, according to one embodiment, that is performed by the AMF <NUM> for PDU session management.

Process <NUM> may begin with step <NUM> in which the AMF <NUM> receives a registration request message transmitted by the UE <NUM>, wherein the registration request message comprises information identifying a PDU session that requires UP resources.

In step <NUM>, in response to receiving the registration request message, the AMF <NUM> transmits to the SMF <NUM>, a UP resource request message for requesting the SMF <NUM> to establish UP resources for the identified PDU session.

In some embodiments, in response to receiving the UP resource request message, the SMF <NUM> triggers a UP function relocation.

In some embodiments, the AMF <NUM> further receives session management information (e.g., N2 SM information) transmitted by the SMF <NUM> in response to the UP resource request message.

In some embodiments, the AMF <NUM> transmits to an access node <NUM> serving the UE <NUM> a message (e.g., N2 PDU Session Request), wherein the message includes the session management information (e.g., N2 SM information).

In some embodiments, the session management information (e.g., N2 SM information) comprises information indicating a quality of service (QoS) and tunnel endpoint information.

In some embodiments, the UP resources for the identified PDU session include data radio bearers (DRBs) on a radio interface and UP tunnels between a UP function and the access node <NUM> serving the UE <NUM>.

<FIG> is a flow chart illustrating a process <NUM>, according to one embodiment, that is performed by the UE <NUM> for PDU session management.

Process <NUM> may begin with step <NUM> in which the UE <NUM> determines a first PDU session that requires UP resources.

In step <NUM>, the UE determines that a registration request message needs to be transmitted (e.g., the UE determines that it needs to perform a mobility registration). In some embodiments, step <NUM> is performed as a result of the UE determining that the first PDU session requires UP resources. In other embodiments, step <NUM> is performed periodically (e.g., before step <NUM>). In some embodiments, the step of the UE determining that a registration request message needs to be transmitted comprises the UE determining that the UE has moved into a new registration area (e.g., the UE has moved out of the registration area in which the UE previously registered).

In step <NUM>, the UE <NUM> transmits a registration request message after determining that i) the first PDU session requires UP resources and ii) a registration request message needs to be transmitted. The registration request message comprises information indicating that the first PDU session requires UP resources.

In some embodiments, the UE may further determine that a second PDU session also requires UP resources and the registration request message transmitted in step <NUM> includes information indicating that both the first and the second PDU sessions require UP resources.

For example, in some embodiments, the UE performs a process <NUM> (see <FIG>), which process includes: <NUM>) the UE periodically determining whether it has moved into a new registration area (step <NUM>) (i.e., determines that a registration request message needs to be sent) and, as a result of determining that it has moved into a new registration area, the UE generates a registration request message (step <NUM>) and transmits the registration request message (step <NUM>), wherein the step of generating the registration request message comprise the UE determining whether the UE has uplink (UL) data to send (step 904a) and, if that is the case, the UE includes in the registration request message information indicating that a PDU session requires UP resources and identifying said PDU session.

In some embodiments, the registration request message includes a registration type identifier. The registration type ID indicates one of the following: (<NUM>) the UE <NUM> is in a non-registered state and is requesting an initial registration; (<NUM>) the UE <NUM> is in a registered state and is initiating a registration due to mobility; and (<NUM>) the UE <NUM> is in the registered state and is initiating the registration due to expiration of a periodic update timer.

In some embodiments, the UP resources for the identified PDU session include data radio bearers (DRBs) on a radio interface and a UP tunnel between a UP function and an access node <NUM> serving the UE <NUM>.

<FIG> is a flow chart illustrating a process <NUM> according to some embodiments.

Process <NUM> includes: UE (<NUM>) determining whether the UE has moved into a new registration area (step <NUM>); and as a result of determining that the UE has moved into a new registration area, the UE generating a registration request message (<NUM>) and transmitting the registration request message (<NUM>), wherein the step of generating the registration request message comprise: the UE determining whether the UE has uplink (UL) data to send (904a) and, if that is the case, the UE includes in the registration request message information i) indicating that a PDU session requires UP resources and ii) identifying said PDU session (904b).

<FIG> is a flow chart illustrating a process <NUM> according to some embodiments. Process <NUM> includes: AMF (<NUM>) receiving a registration request message transmitted by a UE (<NUM>); and the AMF (<NUM>) determining whether the registration request message includes information (e.g., a follow-on flag) indicating that the UE is requesting that a signaling connection with the UE be maintained. In step <NUM> the AMF receives a registration request from a UE. In step <NUM> the AMF determines whether the registration request message includes information (e.g., a follow-on flag) indicating that the UE is requesting that a signaling connection with the UE be maintained. Furthermore, the AMF as shown in step <NUM> may store information that the UE has requested the signaling connection is to be maintained and the AMF may send to a node of a serving RAN information indicating that the UE has requested that the signaling connection be maintained. In step <NUM> the node of the RAN may increase an inactivity timer for the UE as a result of receiving the information sent by the AMF. The node of the RAN may enable AS security to enable connected mode mobility for the UE as shown in step <NUM>.

<FIG> is a flow chart illustrating a process <NUM> according to some embodiments. Process <NUM> includes: the UE (<NUM>) determining that the UE needs to register with a network (<NUM>); and the UE, as a result of determining that the UE needs to register with the network, generating a registration request message (<NUM>) and transmitting the registration request message to the network (<NUM>), wherein generating the registration request message comprises including in the registration request message information (e.g., a follow-on flag) indicating that the UE is requesting that the network maintain a signaling connection with the UE (<NUM>104b).

<FIG> is a block diagram of AMF <NUM> according to some embodiments. As shown in <FIG>, the AMF <NUM> may comprise: a data processing system (DPS) <NUM>, which may include one or more processors <NUM> (e.g., a general purpose microprocessor and/or one or more other processors, such as an application specific integrated circuit (ASIC), field-programmable gate arrays (FPGAs), and the like); network interface <NUM> for use in connecting AMF <NUM> to a network <NUM> such that AMF <NUM> can communicate with the other described functions (e.g., SMF <NUM>) and RAN <NUM>; and local storage unit (a. , "data storage system") <NUM>, which may include one or more non-volatile storage devices and/or one or more volatile storage devices (e.g., random access memory (RAM)). In embodiments where the AMF <NUM> includes a general purpose microprocessor, a computer program product (CPP) <NUM> may be provided. CPP <NUM> includes a computer readable medium (CRM) <NUM> storing a computer program (CP) <NUM> comprising computer readable instructions (CRI) <NUM>. CRM <NUM> may be a non-transitory computer readable medium, such as, but not limited, to magnetic media (e.g., a hard disk), optical media (e.g., a DVD), memory devices (e.g., random access memory), and the like. In some embodiments, the CRI <NUM> of computer program <NUM> is configured such that when executed by data processing system <NUM>, the CRI causes the AMF <NUM> to perform steps described above (e.g., steps described above with reference to the flow charts). In other embodiments, the AMF <NUM> may be configured to perform steps described herein without the need for code. That is, for example, data processing system <NUM> may consist merely of one or more ASICs. Hence, the features of the embodiments described herein may be implemented in hardware and/or software.

<FIG> is a block diagram of a UE <NUM> according to some embodiments. As shown in <FIG>, UE <NUM> may comprise: a data processing system (DPS) <NUM>, which may include one or more processors <NUM> (e.g., a general purpose microprocessor and/or one or more other processors, such as an application specific integrated circuit (ASIC), field-programmable gate arrays (FPGAs), and the like); a radio transmitter <NUM> and a radio receiver <NUM> coupled to an antenna <NUM> for use in wirelessly communicating with a radio access network (RAN) node (e.g., a Tx/Rx Point (TRP)); and local storage unit (a. , "data storage system") <NUM>, which may include one or more non-volatile storage devices and/or one or more volatile storage devices (e.g., random access memory (RAM)). In embodiments where UE <NUM> includes a general-purpose microprocessor, a computer program product (CPP) <NUM> may be provided. CPP <NUM> includes a computer readable medium (CRM) <NUM> storing a computer program (CP) <NUM> comprising computer readable instructions (CRI) <NUM>. CRM <NUM> may be a non-transitory computer readable medium, such as, but not limited, to magnetic media (e.g., a hard disk), optical media (e.g., a DVD), memory devices (e.g., random access memory), and the like. In some embodiments, the CRI <NUM> of computer program <NUM> is configured such that when executed by data processing system <NUM>, the CRI causes UE <NUM> to perform steps described above (e.g., steps described above with reference to the flow charts). In other embodiments, UE <NUM> may be configured to perform steps described herein without the need for code. That is, for example, data processing system <NUM> may consist merely of one or more ASICs. Hence, the features of the embodiments described herein may be implemented in hardware and/or software.

<FIG> is a diagram showing functional modules of an AMF <NUM> according to some embodiments. As shown in the embodiment of <FIG>, the AMF <NUM> comprises a number of functional modules, including: a first obtaining module <NUM> configured to obtain via a receiver a registration request message transmitted by the UE <NUM>, wherein the registration request message comprises information identifying a PDU session that requires UP resources; a first transmitting module <NUM> configured to configured to employ a transmitter to transmit to a SMF <NUM> a UP resource request message for requesting the SMF <NUM> to establish UP resources for the identified PDU session in response to receiving the registration request message; a second obtaining module <NUM> configured to obtain via the receiver session management information (e.g., N2 SM information) transmitted by the SMF <NUM> in response to the UP resource request message; and a second transmitting module <NUM> configured to employ a transmitter to transmit to an access node <NUM> serving the UE <NUM> a message (e.g., N2 PDU Session Request), wherein the message includes the session management information (e.g., N2 SM information). It should be understood that the modules <NUM>-<NUM> in one embodiment may be enabled through software instructions and in another embodiment through hardware, such as ASICs and DSPs, and in further embodiments through a mix of hardware and software.

<FIG> is a diagram showing functional modules of a UE <NUM> according to some embodiments. As shown in the embodiment of <FIG>, The UE <NUM> comprises a number of functional modules, including: a determining module <NUM> configured to determine a first PDU session that requires UP resources; and a first transmitting module <NUM> configured to employ a transmitter to transmit a registration request message, wherein the registration request message comprises information identifying the first PDU session that requires the UP resources. It should be understood that the modules <NUM>-<NUM> in one embodiment may be enabled through software instructions and in another embodiment through hardware, such as ASICs and DSPs, and in further embodiments through a mix of hardware and software.

While various embodiments of the present disclosure are described herein, it should be understood that they have been presented by way of example only, and not limitation. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.

Claim 1:
A method (<NUM>) for Protocol Data Unit, PDU, session management, the method (<NUM>) comprising:
- receiving (<NUM>), at an Access and Mobility Management function entity, AMF (<NUM>), a registration request message transmitted by a user equipment, UE (<NUM>), characterized in that
the registration request message comprises information indicating that one or more PDU sessions require user plane, UP, resources and identifying each of the PDU sessions that require UP resources, wherein the information comprises one or more bits, each of the one or more bits indicating that uplink data needs to be transmitted for a corresponding PDU session of the one or more PDU sessions and that the UP resources are required for the corresponding PDU session,
wherein one or more PDU sessions require UP resources because the UE (<NUM>) has UP data to transmit in the one or more PDU sessions; and
wherein the method comprises:
- in response to receiving the registration request message and if the registration request message indicates that one or more PDU sessions require UP resources, the AMF (<NUM>) transmitting (<NUM>) to a session management function, SMF (<NUM>), a UP resource request message for requesting the SMF (<NUM>) to establish UP resources for at least one of the PDU sessions that requires UP resources.