PDU Session Management

Abstract

The present invention relates to PDU session management, and in particular to a method and apparatus for establishing user plane resources for a PDU session. This is implemented in many embodiments of the method and apparatus, such as for an infrastructure node and a user equipment node. For example, in a session management method for a protocol data unit (PDU), the step is to receive a registration request message sent by a user equipment (UE) at an access and mobility management function entity (AMF), wherein the registration request message includes information indicating that one or more PDU sessions require user plane UP resources and identifying each of the PDU sessions requiring UP resources; and in response to receiving the registration request message, the AMF sends a UP resource request message to a session management function (SMF) for requesting the SMF to establish UP resources for at least one of the PDU sessions requiring UP resources. The method may further include: in response to receiving the UP resource request message, the SMF triggering UP function relocation.

Description

[0001] This application is a divisional application of the Chinese patent application with application number 201780050745.0. The international application date of the original application is December 15, 2017, the priority date is January 10, 2017, and the date of entering the Chinese national phase is February 18, 2019. The name of the invention is “PDU Session Management”. Technical Field

[0002] The present invention relates to PDU session management, and in particular to establishing user plane resources for a PDU session. Background Art

[0003] In the telecommunications field, there is a continuous evolution to provide efficient and reliable solutions for utilizing wireless communication networks. Each new generation presents its own technical challenges for handling the different scenarios and processes required to connect and service devices connected to wireless networks. This is particularly true for cellular telecommunications networks.

[0004] A cellular telecommunications network comprises, at a high level, an access infrastructure and a core infrastructure. The access infrastructure provides wireless access to connected devices and handles the connectivity of these devices. The core infrastructure provides authentication, billing, Quality of Service (QoS) handling and similar user / device management features. In addition, the core network also provides access to external networks, such as, for example, Internet access. It should be noted that a connected device typically refers to a user equipment (UE), but the device does not necessarily need to be a user but can be any type of device connected to the network, i.e. a device capable of wireless communication with a radio access network node, a UE can be, for example, a smartphone, laptop, PC, utility appliance, vehicle, smart sensor, etc. With the advent of the Internet of Things (IoT), many different types of devices, functionalities and solutions are being introduced, involving human interaction or as standalone devices serving different solutions or functionalities.

[0005] The 3rd Generation Partnership Project (3GPP) has begun research on the development and design of the next-generation mobile communication system, also known as the 5G mobile communication system or the Next Generation (NG) system, or simply "5G" or "NG." 3GPP is currently in the process of specifying the 5G radio interface, called New Radio (NR) or "G-UTRA," and the Next Generation Packet Core Network (NG-CN or NGC).

[0006] A user equipment (UE) needs to register with the network in order to receive services that require registration. The registration procedure is used in the following situations: (1) when the UE initially registers to the 5G system; (2) when the UE initiates the registration procedure due to mobility, for example, when the UE switches to a new tracking area (TA) in idle mode; (3) when the UE performs a periodic update due to the expiration of a predetermined inactivity period, etc.

[0007] During initial registration, the Mobile Equipment (ME) Identity is obtained from the UE. The Access and Mobility Management Function (AMF) operator can use the EIR to check the ME Identity. The AMF then passes the ME Identity (IMEISV) to the Unified Data Management (UDM), Session Management Function (SMF), and Policy Control Function (PCF). The AMF is also called the Mobility Management Function (MMF), so the AMF and MMF are equivalent. Summary of the Invention

[0008] When a user equipment (UE) registers with a 5G core network (CN), it is impossible for the access and mobility management function (AMF) to know the user plane (UP) resources required to establish or initiate a specific protocol data unit (PDU) session in which the UE has UP data to send. The present disclosure addresses this problem.

[0009] For example, in one embodiment, the UE includes information in a registration request message (e.g., an attach request message, a tracking area update (TAU), a registration request, etc.) about which PDU session(s) require UP resources (e.g., a data radio bearer (DBR) on a radio interface and a related UP tunnel between a network function in the network). The AMF receives the registration request message sent by the UE, the message including information about which PDU session(s) require UP resources. The AMF requests establishment of UP resources based on the information about which PDU session(s) require UP resources in the registration request message sent by the UE. In response to the request for establishing UP resources, the radio access network (RAN) and (multiple) SMFs allocate UP resources accordingly.

[0010] In many embodiments, the present invention is implemented (for example, in a method for protocol data unit (PDU) session management) by receiving, at an access and mobility management function (AMF), a registration request message sent by a user equipment (UE), wherein the registration request message includes information indicating that one or more PDU sessions require user plane UP resources and identifying each of the PDU sessions requiring UP resources, and in response to receiving the registration request message, the AMF sends, to a session management function (SMF), an UP resource request message requesting the SMF to establish UP resources for at least one of the PDU sessions requiring UP resources. The method may further include: in response to receiving the UP resource request message, the SMF triggering UP function relocation.

[0011] In addition, the registration request message may include a registration type identifier (ID) indicating that the UE is in a registered state and that registration is initiated due to mobility. The method may further include the following steps: receiving session management (SM) information sent by the SMF in response to the UP resource request message, wherein the SM information is N2 SM information, and the AMF sending an N2 PDU session request message to the access node serving the UE, wherein the message includes session management information. The N2 SM information includes information indicating quality of service (QoS) and tunnel endpoint information.

[0012] The UP resources for the identified PDU session requiring UP resources may include a data radio bearer (DRB) on the radio interface and a UP tunnel between the UP function and the access node serving the UE. The registration request message includes a subsequent flag indicating that the UE is requesting the network to maintain a signaling connection with the UE. The method may further include the steps of the AMF storing information (e.g., a local flag) indicating that the UE has requested to maintain the signaling connection, and the AMF sending information to a node of a radio access network (RAN) that is serving the UE, wherein the information sent to the node indicates that the UE has requested to maintain the signaling connection.

[0013] In another embodiment, an access and mobility management function entity AMF is provided for protocol data unit PDU session management, and the AMF includes a data processing system, a data storage system and a network interface, wherein the data processing system is suitable for executing computer-readable instructions stored in the data storage system to: receive a registration request message sent by a user equipment UE via the network interface, wherein the registration request message includes information indicating that one or more PDU sessions require user plane UP resources and identifying each of the PDU sessions requiring UP resources; and in response to receiving the registration request message, send an UP resource request message to the session management function SMF via the network interface to request the SMF to establish UP resources for at least one of the identified PDU sessions requiring UP resources.

[0014] In another embodiment, a method in a user equipment (UE) for protocol data unit (PDU) session management is provided, the method including determining, by the user equipment (UE), that one or more PDU sessions require user plane UP resources, determining, by the UE, that a registration request message needs to be sent, and after determining a) that the registration request message needs to be sent and b) that one or more PDU sessions require UP resources, the UE sends the registration request message, wherein the registration request message includes information indicating that the one or more PDU sessions require UP resources.

[0015] In the UE method, the registration request message may further include a registration type identifier (ID) for identifying the registration type, a UE ID, security parameters, network slice selection assistance information, and network slice selection assistance information (NSSAI). The registration request message may further include a registration type identifier indicating that the UE is in a registered state and that registration is initiated due to mobility. UP resources for the identified PDU session include a data radio bearer (DRB) and an UP tunnel on the radio interface.

[0016] The registration request message may further include a subsequent flag indicating that the UE is requesting the network to maintain a signaling connection with the UE.

[0017] Another embodiment is provided, a user equipment (UE), comprising a data processing system, a data storage system, a wireless transmitter coupled to an antenna, and a receiver, wherein the data processing system is adapted to execute computer-readable instructions to: determine that one or more protocol data unit (PDU) sessions require user plane UP resources, determine that a registration request message needs to be sent using the wireless transmitter, and after determining a) that the registration request message needs to be sent and b) that one or more PDU sessions require UP resources, send the registration request message using the wireless transmitter, wherein the registration request message includes information indicating that the one or more PDU sessions require UP resources.

[0018] The embodiments disclosed herein provide an advantage in that the network can configure UP resources to enable the transfer of UP data for the PDU session(s) indicated in the registration request message sent by the UE. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate various embodiments.

[0020] Figure 1 An exemplary next generation communication architecture is shown.

[0021] Figure 2 is a diagram illustrating the message flow of a process according to one embodiment.

[0022] Figure 3 is a flow chart illustrating a process according to one embodiment.

[0023] Figure 4 is a flow chart illustrating a process according to one embodiment.

[0024] Figure 5 is a block diagram of an AMF according to some embodiments.

[0025] Figure 6 is a block diagram of a UE according to some embodiments.

[0026] Figure 7 is a diagram illustrating the functional modules of AMF according to some embodiments.

[0027] Figure 8 is a diagram illustrating functional modules of a UE according to some embodiments.

[0028] Figure 9 is a flow chart illustrating a process according to one embodiment.

[0029] Figure 10 is a flow chart illustrating a process according to one embodiment.

[0030] Figure 11 is a flow chart illustrating a process according to one embodiment. DETAILED DESCRIPTION

[0031] As mentioned above, the user equipment (UE) 102 needs to register with the network to receive services that require registration. Figure 1 , Figure 1 An exemplary 5G communication system 100 is shown. The 5G communication system 100 shows a point-to-point reference point representation. Figure 1 In the figure, some nodes and functions of the network are shown. A user equipment (UE) 102 is connected to the network via a radio access network node (RAN) 108. The RAN may be, for example, a base station, a NodeB or an eNodeB. It should be noted that the UE may be a mobile phone, such as a smartphone, or some other type of unit with wireless communication capabilities, such as an Internet of Things (IoT) device, a machine-to-machine device, a vehicle, a sensor, a computer, a laptop, etc. The RAN 108 is in turn connected to a core network including a user plane function (UPF) 112, an access and mobility management function (AMF) 104, a session management function (SMF) 106, a policy control function (PCF) 120, and to an external data network (DN) 124. In addition, the network may include an authentication server function / AUSF) 121, a unified data management node (UDM) 122, an application function (AF) 123. These nodes / functions are as follows: Figure 1 The interconnections shown are with different interfaces NG1-NG15, it should be noted that the interfaces may also be denoted by N1 to N15.

[0032] It should be noted that all nodes and functions may be physically located as separate nodes or partially incorporated into different nodes along with other nodes / functions, but are shown as separate entities for illustrative purposes.

[0033] The registration process is utilized in the following situations: (1) when UE 102 initially registers to the 5G system; (2) when UE 102 initiates a registration process due to mobility, such as when UE 102 changes to a new registration area (e.g., a new tracking area (TA)) in idle mode; (3) when UE 102 performs a periodic update due to expiration of a predefined inactivity time period, etc.

[0034] During initial registration, the Mobile Equipment (ME) identity is obtained from the UE 102. The operator's Access and Mobility Management Function (AMF) 104 can check the ME identity with the EIR. The AMF 104 then passes the ME identity (IMEISV) to the Unified Data Management (UDM), Session Management Function (SMF) 106, and Policy Control Function (PCF).

[0035] Figure 2 is a diagram illustrating a message flow of a UE registration procedure 200 according to one embodiment.

[0036] In step 1, UE 102 sends a registration request message to RAN 108. In an embodiment, the registration request message may include: a registration type identifier (ID) for identifying the 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 state information, and radio resource control (RRC) parameters indicating the permanent ID or temporary ID, the selected network, and the NSSAI. The registration type ID indicates whether UE 102 wants to perform "initial registration" (i.e., UE 102 is in a non-registered state), "mobility registration" (i.e., UE 102 is in a registered state and initiates registration due to mobility), or "periodic registration" (i.e., UE 102 is in a registered state and initiates registration due to expiration of a periodic update timer).

[0037] 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 (multiple) data radio bearers and tunnels between the UP function (UPF) and the RAN). In one embodiment, the UE 102 marks the PDU session(s) that require UP resources to be established with an active flag in the registration request message. In some embodiments, the marked PDU session(s) require UP resources to be established because the UE 102 has UP data to send to the network. For example, the registration request message may include a first ordered set of N bits (i.e., a "bitmap"), where each of the N bits corresponds to a different one of N possible PDU sessions that may require UP resources (e.g., the first bit in the string corresponds to the first PDU session, the second bit in the string corresponds to the second PDU session, etc.). In some embodiments, N is equal to the total number of PDU sessions that the UE considers active (e.g., N=3), while in other embodiments, N is equal to the total number of possible active PDU sessions in the UE (e.g., N=16). The value of each bit in the bit string indicates whether the PDU session corresponding to the bit requires UP resources (for example, if bit n is set to a value of 1, the PDU session corresponding to the bit requires UP resources, but if the bit n is set to a value of 0, the corresponding PDU session does not require UP resources). In this way, the UE can signal the identity of the PDU session that requires UP resources to the network.

[0038] Additionally, the Registration Request message may also include information (e.g., a flag) indicating that the UE 102 is requesting a "follow-up"—that is, the UE is requesting that the network maintain a signaling connection with the UE after the registration procedure is complete because, for example, the UE has additional messages to send to the network (e.g., a PDU Session Establishment message).

[0039] In step 2, if the Registration Request message includes an ID (permanent or temporary) that does not indicate a valid AMF, the RAN 108 selects an AMF 104 based on the Radio Access Technology (RAT) and NSSAI (if available).

[0040] In step 3, the RAN 108 sends a registration request message to the AMF 104. In an embodiment, the registration request message sent to the AMF 104 further includes: location information, cell identifier, and RAT type. The location information, cell identifier, and RAT type are related to the cell where the UE is located.

[0041] In step 4, if the Registration Request message includes the UE's temporary ID and the serving AMF 104 has changed since the last registration, the AMF 104 may send an Information Request to the old AMF. The Information Request includes the complete Registration Request message IE to request the UE's permanent ID and Mobility Management (MM) context.

[0042] In step 5, in response to the information request sent by AMF 104, the old AMF responds with an information response. The information response includes the permanent ID, MM context, and SMF information. In some embodiments, the old AMF has stored information about active PDU sessions. If the old AMF has stored information about active PDU sessions, the old AMF includes SMF information including the SMF identifier and the corresponding PDU session identifier in the information response so that AMF 104 can map the PDU session to the SMF.

[0043] In step 6, if the permanent ID is not provided by the UE 102 and is not obtained from the old AMF in the information response, the AMF 104 sends an Identity Request message to the UE 102 to initiate the Identity Request procedure.

[0044] In step 7, in response to the Identity Request message, the UE 102 responds to the AMF 104 with an Identity Response message including the permanent ID.

[0045] In step 8, the AMF 104 selects the AUSF if no Registration Request message with integrity protection is sent or integrity protection is indicated as failed based on the permanent ID included in the Information Response (step 5).

[0046] In step 9, if the AMF 104 selects the AUSF because the Registration Request message was not sent with integrity protection or the integrity protection was indicated as failed, the AUSF initiates authentication of the UE 102 and the NAS security function. Once the security of the Registration Request message is established, the AMF 104 can obtain the IMEI from the UE 102.

[0047] In step 10, if the ME Identity is not provided by the UE 102 in the Registration Request message, nor obtained from the old AMF in the Information Response, the AMF 104 sends an Identity Request to the UE 102 to obtain the UE's ME Identity.

[0048] In step 11, in some embodiments, the AMF initiates an ME identity check.

[0049] In step 11a, the AMF 104 sends a request (e.g., an N11 request) to the SMF 106. If the AMF 104 has changed, the AMF 104 notifies each SMF 106 of the new AMF 104 serving the UE 102 (i.e., the AMF 104 sends a request to each SMF). The new AMF 104 verifies the PDU session status received from the UE 102 using the SMF information received from the old AMF. If the AMF 104 has not changed, the AMF 104 verifies the PDU session status received from the UE 102 using the available SMF information. After the AMF 104 determines the active PDU session in the UE 102, the AMF 104 releases any network resources associated with the inactive PDU session in the UE 102.

[0050] In addition, if the registration request message indicates that one or more PDU sessions require UP resources, then for each such PDU session, the AMF 104 sends a UP resource request to the SMF responsible for processing the PDU session, causing the SMF to establish UP resources for the PDU session. For example, if the registration request message indicates that a PDU session being processed by the SMF 106 requires UP resources, the request sent to the SMF 106 in step 11a will further include a UP resource request.

[0051] In step 11b, in response to the UP resource request, the SMF 106 sends a UP resource response (e.g., N11 response). In some embodiments, the SMF 106 decides to trigger UPF relocation. In some embodiments, the SMF 106 provides 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 the UPF. In some embodiments, the SMF provides SM information in the response only if the AMF specifically requests SM information in the request.

[0052] In step 12, in some embodiments, the AMF 104 selects a UDM based on the UE's 102 permanent ID.

[0053] In step 13, the AMF 104 initiates an update positioning procedure if: (1) the AMF 104 has changed since the last registration; (2) there is no valid subscription context for UE 102 in the AMF 104; or (3) the UE 102 provides a permanent ID that does not refer to a valid context in the AMF 104. When the update positioning procedure is initiated, the UDM initiates a cancel positioning to the old AMF (if applicable). In response to the cancel positioning, the old AMF removes the associated MM context and notifies all possible associated SMFs (multiple). In some embodiments, the interaction between the UDM and the PCF includes mobility restriction related information.

[0054] In step 14, in some embodiments, the AMF 104 selects a PCF based on the permanent ID of the UE 102.

[0055] In step 15, in some embodiments, the AMF 104 sends a UE context establishment request to the PCF to apply the operator policy for the UE 102.

[0056] In step 16, the PCF responds to the UE context establishment request with a UE context establishment which is confirmed to the AMF 104.

[0057] In step 17, in some embodiments, the old AMF sends a UE context termination request to the PCF.

[0058] In step 18, the PCF responds to the UE Context Termination Request with a UE Context Termination confirmed to the old AMF.

[0059] In step 19, the AMF 104 sends the UE context setup (access stratum (AS) security context information) to the RAN 108. If the AMF receives SM information from the SMF 106 in step 11b, the SM information and the N2 PDU session request (quality of service (QoS), tunnel information, etc.) are included in the UE context setup.

[0060] The AMF 104 verifies the presence of the UE 102 in the (new) location and if all checks are successful and the UE marks the PDU session as requiring UP resources or requests a follow-up, the connection is maintained and the AMF requests the RAN to establish a secure connection to the UE by providing the Access Stratum (AS) security context information in the UE Context Setup message sent to the RAN.

[0061] In some embodiments, if the UE is not allowed to register at the current location, the AMF 104 rejects the Registration Request message with an appropriate rejection cause.

[0062] In step 19 a , if the UE context establishment request includes a PDU session request, the RAN 108 performs an RRC connection reconfiguration with the UE 102 to establish a default radio bearer (DRB) for the PDU session request(s) received in step 19 .

[0063] In step 20, the AMF 104 sends a Registration Accept message to the UE 102, indicating that the Registration Request message has been accepted. In an embodiment, the Registration Accept message includes: a temporary ID, a registration area, mobility restrictions, and a PDU session status. The AMF 104 indicates the PDU session status to the UE 102. As a result, the UE removes any internal resources related to the PDU session that is not marked as active in the received PDU session status. If the PDU session status information is in the Registration Request message, the AMF 104 indicates the corresponding PDU session status to the UE 102. In some embodiments, if the AMF 104 assigns a new temporary ID to the UE 102, the Registration Accept message includes the temporary ID. In some embodiments, if mobility restrictions apply to the UE 102, the Registration Accept message includes the mobility restrictions.

[0064] In step 21, in response to the Registration Accept message, UE 102 sends a Registration Complete message to AMF 104. If a new temporary ID is included in the Registration Accept message, the Registration Complete message confirms to AMF 104 that the new temporary ID has been allocated.

[0065] Figure 3 is a flow chart illustrating a process 300 performed by the AMF 104 for PDU session management according to one embodiment.

[0066] Process 300 may begin at step 302, where the AMF 104 receives a registration request message sent by the UE 102, where the registration request message includes information identifying a PDU session requiring UP resources.

[0067] In step 304, in response to receiving the registration request message, the AMF 104 sends a UP resource request message to the SMF 106 for requesting the SMF 106 to establish UP resources for the identified PDU session.

[0068] In some embodiments, in response to receiving the UP resource request message, the SMF 106 triggers UP function relocation.

[0069] In some embodiments, the AMF 104 further receives session management information (e.g., N2 SM information) sent by the SMF 106 in response to the UP resource request message.

[0070] In some embodiments, the AMF 104 sends a message (e.g., N2PDU Session Request) to the access node 108 serving the UE 102, where the message includes session management information (e.g., N2SM information).

[0071] In some embodiments, session management information (eg, N2 SM information) includes information indicating quality of service (QoS) and tunnel endpoint information.

[0072] In some embodiments, the UP resources for the identified PDU session include a data radio bearer (DRB) on the radio interface and a UP tunnel between the UP function and the access node 108 serving the UE 102 .

[0073] Figure 4 is a flow chart illustrating a process 400 performed by UE 102 for PDU session management according to one embodiment.

[0074] Process 400 may begin at step 402, where UE 102 determines a first PDU session requiring UP resources.

[0075] In step 404, the UE determines that a registration request message needs to be sent (e.g., the UE determines that it needs to perform mobility registration). In some embodiments, step 404 is performed as a result of the UE determining that UP resources are required for the first PDU session. In other embodiments, step 404 is performed periodically (e.g., before step 402). In some embodiments, the UE determining that a registration request message needs to be sent includes the UE determining that the UE has moved to a new registration area (e.g., the UE has moved out of a registration area in which the UE was previously registered).

[0076] In step 406, UE 102 sends a registration request message after determining i) that the first PDU session requires UP resources and ii) that a registration request message needs to be sent. The registration request message includes information indicating that the first PDU session requires UP resources.

[0077] In some embodiments, the UE may further determine that the second PDU session also requires UP resources, and the registration request message sent in step 406 includes information indicating that both the first and second PDU sessions require UP resources.

[0078] For example, in some embodiments, the UE performs process 900 (see Figure 9), the process includes: 1) the UE periodically determines whether it has moved into a new registration area (step 902) (i.e., determines that a registration request message needs to be sent), and, as a result of determining that it has moved into the new registration area, the UE generates a registration request message (step 904) and sends the registration request message (step 906), wherein the step of generating the registration request message includes the UE determining whether the UE has uplink (UL) data to send (step 904a), and if this is the case, the UE includes information indicating that a PDU session requires UP resources and identifying the PDU session in the registration request message.

[0079] In some embodiments, the registration request message includes a registration type identifier. The registration type ID indicates one of the following: (1) UE 102 is in a non-registered state and is requesting an initial registration; (2) UE 102 is in a registered state and is initiating registration due to mobility; (3) UE 102 is in a registered state and is initiating registration due to expiration of a periodic update timer.

[0080] In some embodiments, the UP resources for the identified PDU session include a data radio bearer (DRB) on the radio interface and a UP tunnel between the UP function and the access node 108 serving the UE 102 .

[0081] Figure 9 is a flow chart illustrating a process 900 according to some embodiments.

[0082] G1. The process 900 includes: the UE (102) determining whether the UE has moved into a new registration area (step 902); and, as a result of determining that the UE has moved into the new registration area, the UE generating a registration request message (904) and sending the registration request message (906), wherein the step of generating the registration request message includes: the UE determining whether the UE has uplink (UL) data to send (904a), and if so, the UE including in the registration request message information: 1) indicating that UP resources are required for a PDU session, and ii) identifying the PDU session (904b).

[0083] Figure 10is a flow chart illustrating a process 1000 according to some embodiments. The process 100 includes: the AMF (104) receiving a registration request message sent by the UE (102); and the AMF (104) determining whether the registration request message includes information indicating that the UE is requesting to maintain a signaling connection with the UE (e.g., a follow-up flag). In step 1002, the AMF receives the registration request from the UE. In step 1004, the AMF determines whether the registration request message includes information indicating that the UE is requesting to maintain a signaling connection with the UE (e.g., a follow-up flag). In addition, the AMF as shown in step 1006 may store information that the UE has requested that the signaling connection be maintained, and the AMF may send information indicating that the UE has requested to maintain the signaling connection to a node of a serving RAN. In step 1008, as a result of receiving the information sent by the AMF, the node of the RAN may increase an inactivity timer for the UE. As shown in step 1010, the node of the RAN may enable AS security to implement connected mode mobility for the UE.

[0084] Figure 11 1 is a flow chart illustrating a process 1100 according to some embodiments. The process 1100 includes: a UE (102) determining that the UE needs to register with a network (1102); and as a result of determining that the UE needs to register with the network, the UE generates a registration request message (1104) and sends the registration request message to the network (1106), wherein generating the registration request message includes including information (e.g., a follow-up flag) in the registration request message indicating that the UE is requesting the network to maintain a signaling connection with the UE (1104b).

[0085] Figure 5 is a block diagram of the AMF 104 according to some embodiments. Figure 5As shown in FIG, the AMF 104 may include: a data processing system (DPS) 502, which may include one or more processors 555 (e.g., a general-purpose microprocessor and / or one or more other processors, such as an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), etc.); a network interface 505 for connecting the AMF 104 to the network 110 so that the AMF 104 can communicate with other described functions (e.g., SMF 106) and the RAN 108; and a local storage unit (also referred to as a "data storage system") 508, 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 an embodiment where the AMF 104 includes a general-purpose microprocessor, a computer program product (CPP) 541 may be provided. The CPP 541 includes a computer-readable medium (CRM) 542 storing a computer program (CP) 543 including computer-readable instructions (CRI) 544. The CRM 542 may be a non-transitory computer-readable medium, such as, but not limited to, magnetic media (e.g., a hard drive), optical media (e.g., a DVD), a memory device (e.g., a random access memory), etc. In some embodiments, CRI 544 of computer program 543 is configured such that, when executed by data processing system 502, the CRI causes AMF 104 to perform the aforementioned steps (e.g., the steps described above with reference to the flowcharts). In other embodiments, AMF 104 may be configured to perform the steps described herein without requiring code. That is, for example, data processing system 502 may consist solely of one or more ASICs. Thus, the features of the embodiments described herein may be implemented in hardware and / or software.

[0086] Figure 6 is a block diagram of a UE 102 according to some embodiments. Figure 6As shown in FIG, , UE 102 may include: a data processing system (DPS) 602, which may include one or more processors 655 (e.g., a general-purpose microprocessor and / or one or more other processors, such as an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), etc.); a wireless transmitter 605 and a wireless receiver 606 coupled to an antenna 622 for wireless communication with a radio access network (RAN) node (e.g., a Tx / Rx point (TRP)); and a local storage unit (also referred to as a "data storage system") 608, 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 an embodiment where UE 102 includes a general-purpose microprocessor, a computer program product (CPP) 641 may be provided. CPP 641 includes a computer-readable medium (CRM) 642 storing a computer program (CP) 643 including computer-readable instructions (CRI) 644. The CRM 642 can be a non-transitory computer-readable medium, such as, but not limited to, magnetic media (e.g., a hard drive), optical media (e.g., a DVD), a memory device (e.g., a random access memory), etc. In some embodiments, CRI 644 of computer program 643 is configured such that, when executed by data processing system 602, CRI causes UE 102 to perform the aforementioned steps (e.g., the steps described above with reference to the flowcharts). In other embodiments, UE 102 can be configured to perform the steps described herein without requiring code. That is, for example, data processing system 602 can consist solely of one or more ASICs. Thus, the features of the embodiments described herein can be implemented in hardware and / or software.

[0087] Figure 7 is a diagram illustrating functional modules of the AMF 104 according to some embodiments. Figure 7As shown in the embodiment of the present invention, the AMF 104 includes multiple functional modules, including: a first acquisition module 702, which is configured to obtain a registration request message sent by the UE 102 via a receiver, wherein the registration request message includes information for identifying a PDU session requiring UP resources; a first sending module 704, which is configured to, in response to receiving the registration request message, send a UP resource request message to the SMF 106 using a transmitter to request the SMF 106 to establish UP resources for the identified PDU session; a second acquisition module 706, which is configured to obtain session management information (e.g., N2 SM information) sent by the SMF 106 via the receiver in response to the UP resource request message; and a second sending module 708, which is configured to send a message (e.g., N2 PDU session request) to the access node 108 serving the UE 102 using a transmitter, wherein the message includes session management information (e.g., N2 SM information). It should be understood that modules 702-708 in one embodiment may be implemented by software instructions, in another embodiment by hardware (such as an ASIC and DSP), and in yet other embodiments by a mixture of hardware and software.

[0088] Figure 8 1 is a diagram illustrating functional modules of UE 102 according to some embodiments. Figure 8 As shown in the embodiment of FIG, UE 102 includes multiple functional modules, including: a determination module 802 configured to determine a first PDU session requiring UP resources; and a first sending module 804 configured to send a registration request message using a transmitter, wherein the registration request message includes information identifying the first PDU session requiring UP resources. It should be understood that in one embodiment, modules 802-804 may be implemented via software instructions, in another embodiment via hardware (such as an ASIC and a DSP), and in yet another embodiment via a combination of hardware and software.

[0089] Brief description of various disclosed embodiments:

[0090] AMF Examples

[0091] A1. A method (300) for PDU session management, the method (300) comprising:

[0092] receiving (302) at the AMF (104) a registration request message sent by a user equipment UE (102), wherein the registration request message includes information indicating that one or more PDU sessions require user plane UP resources and identifying each of the PDU sessions requiring the UP resources; and

[0093] In response to receiving the registration request message, the AMF (104) sends (304) to the session management function SMF (106) a UP resource request message for requesting the SMF (106) to establish UP resources for at least one of the PDU sessions requiring UP resources.

[0094] A2. The method (300) of embodiment A1, further comprising:

[0095] In response to receiving the UP resource request message, the SMF (106) triggers UP function relocation.

[0096] A3. The method (300) of embodiment A1 or A2, wherein the registration request message further includes a registration type identifier (ID) indicating that the UE (102) is in a registered state and is initiating registration due to mobility.

[0097] A4. The method (300) according to any one of the above embodiments, wherein the method further comprises:

[0098] Receive session management SM information (eg, N2 SM information) sent by the SMF (106) in response to the UP resource request message.

[0099] A5. The method (300) of embodiment A4, further comprising:

[0100] The AMF (104) sends a message (eg, N2 PDU Session Request) to an access node (108) serving the UE (102), wherein the message includes session management information (eg, N2 SM information).

[0101] A6. The method (300) of embodiment A4 or A5, wherein the session management information (eg, N2 SM information) includes information indicating quality of service (QoS) and tunnel endpoint information.

[0102] A7. A method according to any one of the above embodiments, wherein the UP resources for the identified PDU session requiring UP resources include a data radio bearer DRB on the radio interface and a UP tunnel between the UP function and the access node (108) serving the UE (102).

[0103] B1. An AMF (104) for PDU session management, the AMF (104) being adapted to:

[0104] receiving (304) a registration request message sent by a user equipment UE (102), wherein the registration request message includes information indicating that one or more PDU sessions require user plane UP resources and identifying each of the PDU sessions requiring the UP resources; and

[0105] In response to receiving the registration request message, a UP resource request message is sent (304) to a session management function SMF (106) for requesting the SMF (106) to establish UP resources for at least one of the identified PDU sessions requiring UP resources.

[0106] C1. An AMF (104) for PDU session management, the AMF (104) comprising:

[0107] A first acquisition module (702) is configured to acquire, via a receiver, a registration request message sent by a user equipment UE (102), wherein the registration request message includes information indicating that one or more PDU sessions require user plane UP resources and identifying each of the PDU sessions requiring the UP resources; and

[0108] The first sending module (704) is configured to send a UP resource request message to a session management function SMF (106) using a transmitter as a result of receiving the registration request message, wherein the UP resource request message includes information for requesting the SMF (106) to establish UP resources for at least one of the identified PDU sessions requiring UP resources.

[0109] B / C2. The AMF (104) of embodiment B1 or C1, wherein the registration request message further includes a registration type identifier (ID) indicating that the UE (102) is in a registered state and is initiating registration due to mobility.

[0110] B / C3. An AMF (104) according to any one of the above embodiments, wherein

[0111] The AMF (104) is further adapted to receive session management information (e.g., N2 SM information) sent by the SMF (106) in response to the UP resource request message;

[0112] or

[0113] The AMF (104) further includes a second acquisition module (706) configured to acquire, via the receiver, session management information (eg, N2 SM information) sent by the SMF (106) in response to the UP resource request message.

[0114] B / C4. The AMF (104) of embodiment B / C3, wherein

[0115] The AMF (104) is further adapted to send a message (e.g., N2 PDU Session Request) to an access node (108) serving the UE (102), wherein the message includes session management information (e.g., N2 SM information); or

[0116] The AMF (104) further includes a second transmitting module (708) configured to transmit a message (e.g., N2 PDU session request) to an access node (108) serving the UE (102) using a transmitter, wherein the message includes session management information (e.g., N2 SM information).

[0117] B / C5. The AMF (104) of embodiments B / C4 or B / C5, wherein the session management information (e.g., N2 SM information) includes information indicating quality of service (QoS) and tunnel endpoint information.

[0118] B / C6. An AMF (104) according to any of the above embodiments, wherein the UP resources for the identified PDU session include a data radio bearer (DRB) on the radio interface and a UP tunnel between the UP function and the access node (108) serving the UE (102).

[0119] UE embodiment

[0120] D1. A method (400) for PDU session management, the method (400) comprising:

[0121] Determining (402) by a user equipment UE (102) that a first PDU session requires user plane UP resources;

[0122] Determining (404) by the UE that a registration request message needs to be sent; and

[0123] After determining that a) a registration request message needs to be sent and b) the first PDU session requires UP resources, the UE sends (404) a registration request message, wherein the registration request message includes information indicating that the first PDU session requires UP resources.

[0124] D2. The method (400) according to embodiment D1, wherein the registration request message further includes a registration type identifier ID for identifying the registration type, a UE ID (e.g., a permanent ID or a temporary ID), security parameters, and network slice selection assistance information NSSAI.

[0125] D3. The method (400) of embodiment D1 or D2, wherein the registration request message further includes a registration type identifier indicating that the UE (102) is in a registered state and is initiating registration due to mobility.

[0126] D4. The method (400) according to any one of the above embodiments, wherein the UP resources for the identified PDU session include a data radio bearer (DRB) and a UP tunnel on the radio interface.

[0127] E1. A user equipment UE (102) for PDU session management, the UE (102) being adapted to:

[0128] Determining that the first PDU session requires user plane UP resources;

[0129] Determine to send a registration request message; and

[0130] After determining that a) a registration request message needs to be sent and b) the first PDU session requires UP resources, a registration request message is sent, wherein the registration request message includes information indicating that the first PDU session requires UP resources.

[0131] F1. A user equipment UE (102) for PDU session management, the UE (102) comprising:

[0132] A determination module (802) configured to determine: i) whether the first PDU session requires user plane UP resources, and ii) whether a registration request message needs to be sent; and

[0133] The first sending module (804) is configured to use a transmitter to send a registration request message in response to the determination module determining that a registration message needs to be sent, wherein the registration request message includes information identifying a first PDU session requiring UP resources.

[0134] E / F2. The UE (102) of embodiment E1 or F1, wherein the registration request message further includes a registration type identifier (ID) for identifying the registration type, a UE ID (e.g., a permanent ID or a temporary ID), security parameters, and network slice selection assistance information (NSSAI).

[0135] E / F3. The UE (102) of embodiments E1, F1, or E / F2, wherein the registration request message further includes a registration type identifier (ID) indicating that the UE (102) is in a registered state and is initiating registration due to mobility.

[0136] E / F4. The UE (102) according to any one of the above embodiments, wherein the UP resources for the identified PDU session include a data radio bearer (DRB) and a UP tunnel on the radio interface.

[0137] G1. A method (900), comprising:

[0138] The UE (102) determines whether the UE has moved into a new registration area (step 902); and

[0139] As a result of determining that the UE has moved into a new registration area, the UE generates a registration request message (904) and sends the registration request message (906), wherein

[0140] The steps for generating a registration request message include:

[0141] The UE determines whether the UE has uplink (UL) data to send (904a), and if so, the UE includes in the Registration Request message information that: i) indicates that UP resources are required for a PDU session, and ii) identifies the PDU session (904b).

[0142] Additional AMF Examples

[0143] H1. A method (1000), comprising:

[0144] The AMF (104) receives a registration request message sent by the UE (102); and

[0145] The AMF (104) determines whether the registration request message includes information (eg, a subsequent flag) indicating that the UE is requesting to maintain a signaling connection with the UE.

[0146] H2. The method of embodiment H1, further comprising:

[0147] As a result of the AMF determining that the registration request message includes information indicating that the UE is requesting to maintain the signaling connection with the UE, the AMF stores information (e.g., a local flag) indicating that the UE has requested to maintain the signaling connection.

[0148] H3. The method of embodiment H1 or H2, further comprising:

[0149] As a result of the AMF determining that the registration request message includes information indicating that the UE is requesting to maintain the signaling connection with the UE, the AMF sends information to a node (e.g., a base station) of a radio access network (RAN) serving the UE, wherein the information sent to the node indicates that the UE has requested to maintain the signaling connection.

[0150] H4. The method of embodiment H3, wherein the node of the RAN increases an inactivity timer for the UE as a result of receiving the information sent by the AMF.

[0151] H5. A method according to any one of embodiments H3-H4, wherein the information sent by the AMF to the node of the RAN further includes information for implementing access stratum (AS) security (e.g., implementing connected mode mobility).

[0152] H6. The method according to embodiment H5 further includes a node of the RAN implementing AS security to achieve connected mode mobility for the UE.

[0153] I. A device suitable for:

[0154] receiving a registration request message sent by a UE (102); and

[0155] It is determined whether the received registration request message includes information (eg, a subsequent flag) indicating that the UE is requesting to maintain a signaling connection with the UE.

[0156] J. A device comprising:

[0157] an acquisition module, configured to acquire a registration request message sent by the UE (102); and

[0158] The determining module is configured to determine whether the acquired registration request message includes information (eg, a subsequent flag) indicating that the UE is requesting to maintain a signaling connection with the UE.

[0159] Additional UE Embodiments

[0160] H1. A method (1100), comprising:

[0161] The UE (102) determines that the UE needs to register with the network (1102);

[0162] As a result of determining that the UE needs to register with the network, the UE generates a registration request message (1104) and sends the registration request message (1106) to the network, wherein

[0163] Generating the registration request message includes including information (eg, a subsequent flag) in the registration request message indicating that the UE is requesting the network to maintain a signaling connection with the UE (1104b).

[0164] H2. The method of embodiment H1, further comprising:

[0165] The UE determines whether the UE has uplink UL data to send (1104a), where

[0166] As a result of the UE determining that the UE has UL data to transmit, the UE includes information indicating that the UE is requesting the network to maintain a signaling connection with the UE in the registration request message.

[0167] H3. The method of embodiment H1 or H2, further comprising:

[0168] The UE sends a request to establish a PDU session (1108) (in some embodiments, the UE sends the request to establish a PDU session immediately after the UE successfully registers with the network).

[0169] I1. A UE (102), adapted for:

[0170] Determining that the UE needs to register with the network (1102);

[0171] As a result of determining that the UE needs to register with the network, a registration request message is generated (1104) and sent to the network (1106), wherein

[0172] The UE is configured to generate a registration request message by performing a process including including information (eg, a subsequent flag) in the registration request message indicating that the UE is requesting the network to maintain a signaling connection with the UE ( 1104b ).

[0173] J1. A UE (102), comprising:

[0174] A determination module, configured to determine whether the UE needs to register with the network;

[0175] a generating module configured to generate a registration request message as a result of determining that the UE needs to register with the network;

[0176] The sending module is used to send a registration request message to the network using a transmitter, wherein

[0177] The generating module is configured to generate a registration request message by performing a process including including information (eg, a subsequent flag) indicating that the UE is requesting the network to maintain a signaling connection with the UE in the registration request message.

[0178] Although various embodiments of the present disclosure are described herein, it should be understood that they are presented by way of example only and not limitation. Therefore, the breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments. In addition, unless otherwise indicated herein or the context clearly contradicts, the present disclosure encompasses any combination of all possible variations of the above-described elements.

[0179] In addition, although the processes described above and shown in the accompanying drawings are shown as a series of steps, this is for illustrative purposes only. Therefore, it is expected that some steps can be added, some steps can be omitted, the order of the steps can be rearranged, and some steps can be performed in parallel.

Claims

1. A method (300) for protocol data unit (PDU) session management, the method (300) comprising: - receiving (302) at an access and mobility management function (AMF) (104) a registration request message sent by a user equipment (UE) (102), wherein the registration request message includes information indicating one or more PDUs to be activated requiring user plane UP resources and identifying each of the PDU sessions requiring UP resources, wherein the information comprises one or more bits, each of the one or more bits indicating that a corresponding PDU session in the one or more PDU sessions needs to send uplink data and that the corresponding PDU session needs the UP resource, wherein the one or more PDU sessions need the UP resource because the UE (102) has UP data to send in the one or more PDU sessions; and - In response to receiving the registration request message, the AMF (104) sends (304) to a session management function SMF (106) a request message for requesting the SMF (106) to activate UP resources for at least one of the PDU sessions identified in the one or more PDU sessions.

2. The method (300) of claim 1, further comprising: - In response to receiving the UP resource request message, the SMF (106) triggers UP function relocation.

3. The method (300) according to claim 1 or 2, wherein: The registration request message further includes a registration type identifier ID, which indicates that the UE (102) is in a registered state and is initiating registration due to mobility.

4. The method (300) according to claim 1 or 2, wherein: The method further comprises: - receiving session management (SM) information sent by the SMF (106) in response to the UP resource request message, wherein the SM information includes N2SM information that the AMF should provide to the access network node (108) serving the UE.

5. The method (300) according to claim 4, wherein: The method further comprises: - the AMF (104) sends an N2 request message to the access network node (108) serving the UE (102), wherein the N2 request message includes the N2SM information sent by the SMF to the AMF in response to the request message from the AMF requesting the SMF to activate the UP resources.

6. The method (300) of claim 4, wherein: The N2SM information includes quality of service (QoS) information and tunnel information.

7. The method according to claim 1 or 2, wherein: The UP resources include a data radio bearer (DRB) on a radio interface and a UP tunnel between a UP function and the access network node (108) serving the UE (102).

8. The method according to claim 1 or 2, wherein: The registration request message includes a subsequent flag, where the subsequent flag indicates that the UE is requesting the network to maintain a signaling connection with the UE.

9. The method according to claim 8, further comprising the steps of: - the AMF stores information indicating that the UE has requested to maintain the signalling connection, and - the AMF sends information to a node of a radio access network RAN ​​serving the UE, wherein The information sent to the node indicates that the UE has requested to maintain the signaling connection.

10. An access and mobility management function entity AMF (104) for protocol data unit (PDU) session management, the AMF (104) comprising a data processing system (502), a data storage system (508) and a network interface (505), wherein: The data processing system is adapted to execute computer-readable instructions stored in the data storage system to: - receiving (304) via the network interface (505) a registration request message sent by a user equipment UE (102) in response to a PDU session to be activated requiring establishment of UP resources, wherein the registration request message comprises a list of PDU sessions to be activated, and wherein the UE (102) is in a registered state and is initiating registration due to mobility or periodic registration update; and - in response to receiving the registration request message, sending (304) to a session management function SMF (106) via the network interface (505) a request message for requesting the SMF (106) to activate UP resources for at least one of the identified PDU sessions identified in the list of PDU sessions.

11. The AMF (104) according to claim 10, wherein The registration request message further includes a registration type identifier ID, which indicates that the UE (102) is in a registered state and is initiating registration due to mobility.

12. The AMF (104) according to any one of claims 10 to 11, wherein The AMF (104) is further adapted to receive session management information sent by the SMF (106) in response to the UP resource request message, wherein the session management information includes N2SM information that the AMF should provide to the access network node (108) serving the UE.

13. The AMF (104) according to claim 12, wherein - the AMF (104) is further adapted to send an N2 request message to the access network node (108) serving the UE (102), wherein the N2 request message includes the N2SM information sent by the SMF to the AMF in response to the request message from the AMF requesting the SMF to activate the UP resources.

14. The AMF (104) according to claim 12, wherein The session management information includes quality of service (QoS) information and tunnel information.

15. The AMF (104) according to any one of claims 10 to 11, wherein The UP resources include a data radio bearer (DRB) on a radio interface and a UP tunnel between a UP function and the access network node (108) serving the UE (102).

16. The AMF according to any one of claims 10 to 11, wherein The registration request message includes a subsequent flag, where the subsequent flag indicates that the UE is requesting the network to maintain a signaling connection with the UE.

17. A method (400) in a user equipment (UE) (102) for protocol data unit (PDU) session management, the method (400) comprising: - determining (402) by the user equipment UE (102) that the UE (102) has uplink UL data to be sent in one or more PDU sessions, and that the one or more PDU sessions to be activated require establishment of user plane UP resources; - determining (404) by the UE that a registration request message needs to be sent; as well as - after determining that a) the registration request message needs to be sent and b) the UE (102) has UL data to be sent in the one or more PDU sessions and the one or more PDU sessions need to establish UP resources, the UE sends (404) the registration request message, wherein the registration request message includes information indicating that the one or more PDU sessions need UP resources; The information includes one or more bits, and each of the one or more bits indicates that a corresponding PDU session in the one or more PDU sessions needs to send uplink data and that the corresponding PDU session needs the UP resources.

18. The method (400) of claim 17, wherein: The registration request message further includes a registration type identifier ID for identifying a registration type, a UE ID, security parameters, network slice selection assistance information, and network slice selection assistance information NSSAI.

19. The method (400) according to claim 17 or 18, wherein: The registration request message further includes a registration type identifier indicating that the UE (102) is in a registered state and is initiating registration due to mobility.

20. The method (400) according to claim 17 or 18, wherein: The UP resources for the identified PDU session include a data radio bearer (DRB) and a UP tunnel on a radio interface.

21. The method according to claim 17 or 18, wherein The registration request message includes a subsequent flag, where the subsequent flag indicates that the UE is requesting the network to maintain a signaling connection with the UE.

22. A user equipment (UE) (102) comprising a data processing system (602), a data storage system (608), a wireless transmitter (605) coupled to an antenna (622), and a receiver (606), wherein: The data processing system is adapted to execute computer-readable instructions for: -Determining that one or more protocol data unit (PDU) sessions to be activated require establishment of user plane UP resources; - determining that a registration request message needs to be sent using said wireless transmitter (605); as well as - after determining that a) the registration request message needs to be sent and b) UP resources need to be established for the one or more PDU sessions to be activated, sending the registration request message using the wireless transmitter (605), wherein the registration request message includes a list of PDU sessions to be activated and wherein the UE (102) is in a registered state and is initiating registration due to mobility or periodic registration update.

23. The UE (102) according to claim 22, wherein The registration request message further includes a registration type identifier ID for identifying a registration type, a UE ID, a permanent ID or a temporary ID, security parameters, and network slice selection assistance information NSSAI.

24. The UE (102) according to claim 22 or 23, wherein The registration request message further includes a registration type identifier ID, which indicates that the UE (102) is in a registered state and is initiating registration due to mobility.

25. The UE (102) according to claim 22 or 23, wherein The UP resources for the identified PDU session include a data radio bearer (DRB) and a UP tunnel on a radio interface.

26. The UE (102) according to claim 22 or 23, wherein The registration request message further includes a subsequent flag, where the subsequent flag indicates that the UE is requesting the network to maintain a signaling connection with the UE.

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