MA PDU session and user plane resource establishment method and user equipment

Abstract

A method of establishing and initiating an MA PDU session for data transmission through a selected access is presented. The UE initiates a PDU session establishment procedure requested by the UE. Once the UE receives a PDU session setup accept message with an ATSSS Container IE, the UE may consider that an MA PDU session has been initiated and user plane resources have been successfully established on the selected access. A method of converting an SA PDU session into an MA PDU session for data transmission through a selected access is proposed. The UE initiates a PDU session modification procedure requested by the UE. Once the UE receives a PDU session modification command message with an ATSSS Container IE, the UE may consider that the SA PDU session has been converted to the MA PDU session and successfully establish user plane resources on the selected access.

Description

[0001] Cross-references

[0002] The present invention claims the following priority: U.S. Provisional Patent Application No. 63 / 093,326, filed on October 19, 2020, and entitled “MA PDU Fail to see UP resource establishment” and U.S. Patent Application No. 17 / 478,578, filed on September 17, 2021. The above-mentioned U.S. patent documents are hereby incorporated by reference. Technical Field

[0003] Embodiments of the present invention generally relate to wireless communications, and, more particularly, to methods for handling multi-access (MA) protocol data unit (PDU) sessions and user plane resource establishment for data transmission. Background Art

[0004] Wireless communication networks have grown exponentially over the years. Long-Term Evolution (LTE) systems offer high peak data rates, low latency, improved system capacity, and low operating costs due to a simple network architecture. LTE systems, also known as 4th Generation (4G) systems, also provide seamless integration with older networks such as Global System For Mobile Communications (GSM), Code Division Multiple Access (CDMA), and Universal Mobile Telecommunications System (UMTS). In an LTE system, the evolved universal terrestrial radio access network (E-UTRAN) includes multiple evolved Node-Bs (eNodeBs or eNBs) that communicate with multiple mobile stations called user equipment (UE). The 3rd Generation Partnership Project (3GPP) is a non-profit organization dedicated to the development of LTE networks. rd5G NR systems.

[0005] In 5G / NR, a PDU session defines the association between a UE and a data network that provides PDU connection services. PDU session establishment is a parallel process to the packet data network (PDN) connection (bearer) process in 4G / LTE. Each PDU session is identified by a PDU session ID (PSI) and includes multiple Quality of Service (QoS) flows and QoS rules. Each PDU session can be established through a 5G access network (e.g., a 3GPP radio access network (RAN) or a non-3GPP RAN). The network / UE can initiate different PDU session processes, such as PDU session establishment, PDU session modification, and PDU session release.

[0006] Operators are looking for ways to balance data traffic between mobile cellular networks and non-3GPP accesses in a way that is transparent to users and reduces mobile network congestion. In the 5G system (5GS), the UE can be connected to 3GPP access and non-3GPP access at the same time (using 3GPP Non-Access Stratum (NAS) signaling), so 5GS is able to use multiple access to improve user experience and optimize service distribution between various accesses. Therefore, 3GPP introduced MA PDU sessions in 5GS. MA PDU sessions use one 3GPP access network or one non-3GPP access network at a time, or use one 3GPP access network and one non-3GPP access network at the same time.

[0007] For a UE registered to the same Public Land Mobile Network (PLMN) through both 3GPP access and non-3GPP access, the UE can initiate a UE-requested PDU session establishment procedure by sending a PDU SESSION ESTABLISHMENT REQUEST to the network (NW) through the selected access to activate an MA PDU session. However, when the UE receives the PDU SESSION ESTABLISHMENT ACCEPT message, the UE does not consider that the MA PDU session has been successfully established. The UE needs to wait for the "indication of establishing user plane resources in 3GPP access" and the "indication of establishing user plane resources in non-3GPP access" before the UE considers that the MA PDU session has been successfully established.

[0008] Similarly, for a UE registered to the same PLMN via both 3GPP access and non-3GPP access, the UE can initiate a UE-requested PDU session modification procedure by sending a PDU SESSION MODIFICATION REQUEST to the network via the selected access to convert a single access (SA) PDU session into an MA PDU session. However, when the UE receives a PDU SESSION MODIFICATION COMMAND message, the UE does not consider the PDU session to have been successfully converted into an MA PDU session. The UE needs to wait for the "indication of establishing user plane resources in 3GPP access" and the "indication of establishing user plane resources in non-3GPP access" before the UE considers the PDU session to have been successfully converted into an MA PDU session.

[0009] A solution is needed to enable the UE to start or convert an MA PDU session for data transmission during a PDU session establishment process or a PDU session modification process. Summary of the invention

[0010] A method for establishing and starting an MA PDU session for data transmission through a selected access is proposed. In one embodiment, the UE sends a PDU session establishment request to the NW through the selected access to initiate a UE-requested PDU session establishment process to start the MA PDU session. Once the UE receives a PDU session establishment accept message with an Access Traffic Steering, Switching, Splitting (ATSSS) container information element (IE), the UE can consider that the MA PDU session has been started and the user plane resources have been successfully established on the selected access, and start data transmission through the selected access of the MA PDU session without waiting for receiving an explicit indication from a lower layer (the user plane resources are established on the 3GPP access and the non-3GPP access).

[0011] A method for converting an SA PDU session to an MA PDU session for data transmission through selected access is proposed. In one embodiment, the UE sends a PDU session modification request to the NW through the selected access to initiate a UE-requested PDU session modification process to convert the SA PDU session to an MA PDU session. Once the UE receives the PDU session modification command message with the ATSSS container IE, the UE can consider that the SA PDU session has been converted to an MA PDU session and that user plane resources have been successfully established on 3GPP (selected access), and start data transmission through the 3GPP access (selected access) of the MA PDU session without waiting for receiving an explicit indication from a lower layer (user plane resources are established on 3GPP access and non-3GPP access).

[0012] The MA PDU session and user plane resource establishment method proposed in the present invention can advance the time when the UE can start transmitting data in the scenario of establishing and starting an MA PDU session, and in the scenario of converting an SA PDU session into an MA PDU session.

[0013] Other embodiments and advantages are described in the detailed description that follows. This summary is not intended to define the invention. The invention is defined by the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings depict embodiments of the present invention, wherein like numerals refer to like parts.

[0015] Figure 1An exemplary 5G network in accordance with novel aspects is described that supports early data transfer for a MA PDU session establishment or MA PDU session modification procedure.

[0016] Figure 2 A simplified block diagram of a UE and network entities according to an embodiment of the present invention is described.

[0017] Figure 3 An implementation is described in which a MAPDU session is established after a UE registers with a network via 3GPP and non-3GPP access types belonging to the same PLMN.

[0018] Figure 4 An implementation of the MA PDU session establishment procedure and timeline is described when the UE considers that an MA PDU session has been started for early data transmission.

[0019] Figure 5 An implementation method for converting an SA PDU session to an MA PDU session after an inter-system change from an Evolved Packet System (EPS) to 5GS is described.

[0020] Figure 6 An implementation of the MA PDU session modification procedure and timeline is described when the UE considers that the SA PDU session has been converted to an MA PDU session for early data transmission.

[0021] Figure 7 is a flow chart of a method of processing MA PDU session establishment for early data transmission in accordance with novel aspects.

[0022] Figure 8 is a flow chart of a method of processing MA PDU session establishment for early data transmission in accordance with novel aspects. DETAILED DESCRIPTION

[0023] Reference will now be made in detail to some embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

[0024] Figure 1An exemplary 5G network 100 according to novel aspects is described, which supports early data transmission of MA PDU session establishment or MA PDU session modification procedures. The 5G network 100 includes a user equipment UE 101, a 3GPP radio (e.g., NR) access network RAN ​​102, a non-3GPP RAN 103, an access and mobility management function (AMF) 110, a session management function (SMF) 111, a non-3GPP interworking function (N3IWF) 112, a user plane function (UPF) and a data network 120. The AMF communicates with the base station, the SMF and the UPF for access and mobility management of wireless access devices in the 5G network 100. The SMF is mainly responsible for interacting with the decoupled data plane, creating, updating and removing PDU sessions, and managing session contexts with the UPF. The N3IWF function connects the 5G core network control plane function and is responsible for routing messages outside the 5G RAN.

[0025] At the access stratum (AS) layer, the RAN provides radio access to the UE 101 via radio access technology (RAT). At the NAS layer, the AMF / SMF communicates with the RAN and 5GC to perform access and mobility management and PDU session management for radio access devices in the 5G network 100. The 3GPP RAN 102 includes base stations (gNBs) that provide radio access to the UE 101 via various 3GPP RATs (including 5G, 4G, 3G, and 2G). The non-3GPP RAN 103 includes an access point (AP) that provides radio access to the UE 101 through non-3GPP (including Wireless Fidelity (WiFi)). The UE 101 accesses the data network 120 through the 3GPP RAN 102, AMF 110, SMF 111 and UPF 113. The UE 101 accesses the data network 120 through the non-3GPP RAN 103, N3IWF 112, AMF 110 and UPF 113. The UE 101 is configured with a radio frequency (RF) module or transceiver or multiple RF transceiver modules or to provide services through different RAT / CNs. The UE 101 can be a smartphone, a wearable device, an Internet of Things (IoT) device, a tablet computer, etc.

[0026] In 5G / NR, a PDU session defines the association between a UE and a data network that provides a PDU connection service. Each PDU session can be established through a 3GPP RAN or a non-3GPP RAN for radio access. 5G session management (5GSM) of PDU sessions through 3GPP access and non-3GPP access is managed by AMF and SMF through NAS signaling. In 5GS, the UE can be connected to 3GPP access and non-3GPP access at the same time (using 3GPP NAS signaling), so 5GS is able to use multiple access to improve user experience and optimize service distribution between various accesses. Therefore, 3GPP introduced MA PDU sessions in 5GS. MA PDU sessions use one 3GPP access network or one non-3GPP access network at a time, or one 3GPP access network and one non-3GPP access network at the same time. In addition, the UE and the network support the ATSSS function to allocate services to established MA PDU sessions through 3GPP access and non-3GPP access.

[0027] For UE 101 registered to the same PLMN through both 3GPP access and non-3GPP access, the UE can initiate the UE-requested PDU session establishment process by sending a PDU session establishment request to the NW through the selected access to start the MA PDU session (step 131). However, in the prior art, when the UE receives the PDU session establishment accept message with the ATSSS container IE (step 132), the UE does not consider that the MA PDU session has been successfully established. The UE needs to wait for the "indication of establishing user plane resources in 3GPP access" (step 133) and the "indication of establishing user plane resources in non-3GPP access" (step 134), and then the UE will consider that the MA PDU session has been successfully established.

[0028] Similarly, for UE 101 registered to the same PLMN through both 3GPP access and non-3GPP access, the UE can initiate a UE-requested PDU session modification process by sending a PDU session modification request to the network through the selected access to convert the SA PDU session into an MA PDU session (step 131). However, in the prior art, when the UE receives the PDU session modification command message (step 132), the UE does not consider that the PDU session has been converted into an MA PDU session. The UE needs to wait for "an indication of establishing user plane resources in 3GPP access" (step 133) and "an indication of establishing user plane resources in non-3GPP access" (step 134) before the UE considers that the PDU session has been converted into an MA PDU session.

[0029] According to one novel aspect, once UE 101 receives a PDU session establishment accept message with an ATSSS container IE (step 132), the UE may consider that an MA PDU session has been initiated and user plane resources have been successfully established on the selected access, and start data transmission through the selected access of the MA PDU session without waiting for receiving an explicit indication from the lower layer (user plane resources are established on 3GPP access and non-3GPP access). Similarly, once UE 101 receives a PDU session modification command message with an ATSSS container IE (step 132), the UE may consider that an SA PDU session has been converted to an MA PDU session and user plane resources have been successfully established on 3GPP (selected access), and start data transmission through the 3GPP access (selected access) of the MA PDU session without waiting for receiving an explicit indication from the lower layer (user plane resources are established on 3GPP access and non-3GPP access).

[0030] Figure 2 A simplified block diagram of a wireless device (e.g., UE 201 and network entity 211) according to an embodiment of the present invention is described. The network entity 211 can be a base station and / or an AMF / SMF. The network entity 211 has an antenna 215, which sends and receives radio signals. The RF transceiver 214 is coupled to the antenna 215, receives RF signals from the antenna 215, converts them to baseband signals, and sends them to the processor 213. The RF transceiver 214 also converts the baseband signals received from the processor 213, converts them to RF signals, and sends them to the antenna 215. The processor 213 processes the received baseband signals and calls different functional modules to perform functions in the network entity 211. The memory 212 stores program instructions and data 220 to control the operation of the network entity 211. In Figure 2 In the example of FIG. 1 , the network entity 211 also includes a protocol stack 280 and a set of control function modules and circuits 290. In one example, the system modules and circuits 290 include a PDU session processing circuit 231 that performs PDU session establishment and modification procedures, a registration processing circuit 232 that performs registration, and a configuration and control circuit 233 that processes configuration and control parameters for mobility management and session management.

[0031] Similarly, UE 201 has a memory 202, a processor 203, and an RF transceiver 204. The RF transceiver 204 is coupled to an antenna 205, receives RF signals from the antenna 205, converts them to baseband signals, and sends them to the processor 203. The RF transceiver 204 also converts the baseband signals received from the processor 203, converts them to RF signals, and sends them to the antenna 205. The processor 203 processes the received baseband signals and calls different functional modules and circuits to perform functions in the UE 201. The memory 202 stores program instructions and data 210 to control the operation of the UE 201 by the processor. Suitable processors include, for example, special purpose processors, digital signal processors (digital signal processors, DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, controllers, microcontrollers, application specific integrated circuits (ASIC), field programmable gate arrays (file programmable gate array, FPGA) circuits and other types of integrated circuits (IC) and / or state machines. Features of UE 201 may be implemented and configured using a processor in association with software.

[0032] UE 201 also includes a set of functional modules and control circuits that perform the functional tasks of UE 201. The protocol stack 260 includes a NAS layer for communicating with the AMF / SMF entity connected to the core network, a Radio Resource Control (RRC) layer for higher-level configuration and control, a Packet Data Convergence Protocol / Radio Link Control (PDCP / RLC) layer, a Media Access Control (MAC) layer, and a Physical (PHY) layer. The system modules and circuits 270 can be implemented and configured by hardware, firmware, software, and any combination thereof. When the processor executes the functional modules and circuits through program instructions in the memory, they cooperate with each other to enable UE 201 to execute implementation plans and functional tasks and features in the network.

[0033] In one example, the system modules and circuits 270 include a PDU session processing circuit 221 that performs a PDU session establishment and modification process with a network, a registration processing circuit 222 that performs registration with a network through 3GPP and non-3GPP access, and a configuration and control circuit 223 that processes configuration and control parameters for mobility management and session management. In one example, once the UE receives a PDU session establishment accept message with an ATSSS container IE or receives a PDU session modification command message with an ATSSS container IE, the UE may consider that the MA PDU session has been initiated or switched and that user plane resources have been successfully established on the selected access, and start data transmission through the selected access of the MA PDU session without waiting for receiving an explicit indication from the lower layer (user plane resources are established on 3GPP access and non-3GPP access).

[0034] Figure 3 An implementation method of establishing a MAPDU session after the UE registers to the network through 3GPP and non-3GPP access types belonging to the same PLMN is described. UE 301 registers to the PLMN network through a 3GPP access type via a 3GPP base station gNB 302. UE301 also registers to the same PLMN network through a non-3GPP access type via a 3GPP AP 303. UE 301 initiates a PDU session establishment process with the network through a 3GPP or non-3GPP access type to establish a MA PDU session. The initiation of the MA PDU connection service refers to the establishment of user plane resources on 3GPP access and non-3GPP access. Since UE 301 registers to the network through two RAT access types belonging to the same PLMN, a MA PDU session with PSI=1 is established on both 3GPP and non-3GPP access types, and then user plane resources are established on both 3GPP and non-3GPP access types. In one novel aspect, once the UE receives a PDU session establishment accept message with an ATSSS container IE, the UE may consider that the MA PDU session has been initiated and that user plane resources have been successfully established on the selected access, and start data transmission over the selected access for the MA PDU session without waiting for receiving an explicit indication (user plane resources are established on 3GPP access and non-3GPP access).

[0035] Figure 4An implementation of an MA PDU session establishment process and timeline when the UE believes that an MA PDU session has been initiated for early data transmission is described. The UE registers to the network via 3GPP and non-3GPP access types belonging to the same PLMN. As shown by arrow 410, at time t1, the UE establishes a MAPDU session by initiating a PDU session establishment process with the network on a selected access type. Specifically, the UE sends a PDU session establishment request message to the network via the selected access to initiate an MA PDU session (PSI=1, type=MA PDU). At time t2, the UE receives a PDU session establishment accept message with an ATSSS container IE from the network. At time t3, the UE receives an indication from a lower layer (e.g., via an RRC reconfiguration message) indicating that user plane resources have been established on the selected access. At time t4, the UE receives another indication from the lower layer indicating that user plane resources have been established on another access. In this example, the UE receives an accept message at time t2, which is before the first indication is received at time t3. Upon receiving the Accept message at time t2, the UE considers that the MA PDU session has been started and user plane resources have been successfully established on the selected access, and starts data transmission through the selected access of the MA PDU session without waiting for the two indications of time t3 and t4.

[0036] As shown by arrow 420, at time t1, the UE initiates a PDU session establishment process with the network through the selected access type to establish an MA PDU session. Specifically, the UE sends a PDU session establishment request message to the network through the selected access to start the MA PDU session (PSI=1, type=MA PDU). At time t2, the UE receives an indication from the lower layer (for example, via an RRC reconfiguration message) indicating that user plane resources are established on the selected access. At time t3, the UE receives a PDU session establishment accept message with an ATSSS container IE from the network. At time t4, the UE receives another indication from the lower layer indicating that user plane resources have been established on another access. In this example, the UE receives an accept message at time t3, which is after the first indication is received at time t2. Once the accept message is received at time t3, the UE considers that the MA PDU session has been started and the user plane resources have been successfully established on the selected access, and starts data transmission through the selected access of the MA PDU session without waiting for the indication at time t4.

[0037] In another embodiment, after receiving the PDU session establishment accept message, if the UE does not receive the second indication from the network, the UE starts a timer to wait for the second indication. If the UE fails to receive the second indication from the network when the timer expires, the UE re-initiates the UE-requested PDU session establishment process by sending a PDU session establishment request message on the second access type to establish user plane resources on the second access type.

[0038] Figure 5 An implementation method for converting an SA PDU session to an MA PDU session after an inter-system change from EPS to 5GS is described. The UE establishes a PDN connection in EPS. When an inter-system change from EPS to 5GS occurs, the PDN connection is mapped to a corresponding PDU session, for example, an SA PDU with PSI=1 accessed via 3GPP. Note that UE 501 is registered to the PLMN via a 3GPP base station gNB 502 through a 3GPP access type. UE 501 is also registered to the same PLMN via a non-3GPP access point AP 503 through a non-3GPP access type. Then, UE 501 initiates a UE-requested PDU session modification procedure by sending a PDU session modification request message to the network via 3GPP access (selected access) to convert the SA PDU session to an MA PDU session. In a UL-NAS transfer message (the UL-NAS transfer message includes a PDU session modification request message), the UE sets the request type IE to: 1) "Modification request" and includes the MAPDU session information IE set to "MA PDU session network upgrade allowed"; or 2) "MA PDU request". In one novel aspect, once the UE receives the PDU session modification command message with the ATSSS container IE, the UE can consider that the SA PDU session has been converted to an MA PDU session and that user plane resources have been successfully established on 3GPP (selected access), and start data transmission through the 3GPP access (selected access) of the MA PDU session without waiting for receiving an explicit indication from the lower layer (user plane resources are established on 3GPP access and non-3GPP access).

[0039] Figure 6An implementation of the MA PDU session modification process and timeline when the UE believes that the SA PDU session has been converted to an MA PDU session for early data transmission is described. The UE registers to the network through 3GPP and non-3GPP access types belonging to the same PLMN. As shown by arrow 610, at time t0, the UE performs an inter-system change from EPS to 5GS, and the PDN connection is mapped to the corresponding SA PDU session. At time t1, the UE initiates a PDU session modification process with the network through 3GPP to convert the SA PDU session to a MAPDU session. Specifically, the UE sends a PDU session modification request message to the network through 3GPP access to convert the SA PDU to a MAPDU. At time t2, the UE receives a PDU session modification command message with an ATSSS container IE from the network. At time t3, the UE receives an indication from a lower layer (e.g., via an RRC reconfiguration message) indicating that user plane resources have been established on 3GPP access. At time t4, the UE receives another indication from a lower layer indicating that user plane resources have been established on a non-3GPP access. In this example, the UE receives the command message at time t2, which is before the first indication is received at time t3. Once the command message is received at time t2, the UE considers that it has switched to an MA PDU session and that user plane resources have been successfully established on the 3GPP access, and starts data transmission over the 3GPP access of the MA PDU session without waiting for indications at times t3 and t4.

[0040] As shown by arrow 620, at time t0, the UE performs an inter-system change from EPS to 5GS, and the PDN connection is mapped to the corresponding SA PDU session. At time t1, the UE initiates a PDU session modification process with the network through 3GPP to convert the SA PDU session to an MA PDU session. Specifically, the UE sends a PDU session modification request message to the network through 3GPP access to convert the SA PDU to an MA PDU. At time t2, the UE receives an indication from a lower layer (e.g., via an RRC reconfiguration message) indicating that user plane resources have been established on 3GPP access. At time t3, the UE receives a PDU session modification command message with an ATSSS container IE from the network. At time t4, the UE receives another indication from the lower layer indicating that user plane resources have been established on non-3GPP access. In this example, the UE receives the command message at time t3, which is after the first indication is received at time t2. Upon receiving the command message at time t3, the UE considers that it has switched to an MA PDU session and has successfully established user plane resources on the 3GPP access, and starts data transmission over the 3GPP access of the MA PDU session without waiting for an explicit indication at time t4.

[0041] In another embodiment, after receiving the PDU session modification command message, if the UE does not receive the second indication from the network, the UE starts a timer to wait for the second indication. If the UE fails to receive the second indication from the network when the timer expires, the UE re-initiates the UE-requested PDU session establishment procedure by sending a PDU session establishment request message on the second access type to establish user plane resources on the second access type.

[0042] Figure 7 is a flow chart of a method for processing MA PDU session establishment for early data transmission according to a novel aspect. In step 701, a UE establishes an MA PDU session. The UE registers to a PLMN via a first access type and a second access type. In step 702, the UE sends a PDU session establishment request message via the first access type and receives a PDU session establishment accept message in response. In step 703, the UE receives a first indication from the network indicating that user plane resources are to be established on the first access type. In step 704, the UE receives a second indication from the network indicating that user plane resources are to be established on the second access type, wherein upon receiving the PDU session establishment accept message, the UE considers that the MA PDU session has been initiated and starts data transmission.

[0043] Figure 8 is a flow chart of a method for handling MA PDU session modification for early data transmission according to novel aspects. In step 801, the UE maintains an SA PDU session. The UE registers to a PLMN via a first access type and a second access type. In step 802, the UE sends a PDU session modification request message via the first access type to convert the SA PDU session to an MA PDU session, and receives a PDU session modification command message in response. In step 803, the UE receives a first indication from the network indicating establishment of user plane resources on the first access type. In step 804, the UE receives a second indication from the network indicating establishment of user plane resources on the second access type, wherein when the PDU session modification command message is received, the UE considers that the conversion to a MAPDU session has been completed and starts data transmission.

[0044] Although the present invention has been described in conjunction with certain specific embodiments for instructional purposes, it is not limited thereto. Accordingly, various modifications, adaptations and combinations of the various features of the described embodiments may be effected without departing from the scope of the present invention as set forth in the claims.

Claims

1. A method for establishing a multiple access protocol data unit session and user plane resources, characterized in that: include: establishing a multiple access protocol data unit session by a user equipment, wherein the user equipment is registered with a public land mobile network via a first access type and a second access type; A protocol data unit session establishment request message is sent through the first access type, and a protocol data unit session establishment acceptance message is received as a response, the user equipment considers that the multiple access protocol data unit session has been started and that user plane resources have been established on the first access, and when the protocol data unit session establishment acceptance message is received, the user equipment starts data transmission through the first access type.

2. The method for establishing a multiple access protocol data unit session and user plane resources as claimed in claim 1, characterized in that: The protocol data unit session establishment accept message includes an access service control conversion split container resource element.

3. The method for establishing a multiple access protocol data unit session and user plane resources as claimed in claim 1, characterized in that: The user equipment considers that user plane resources are subsequently established on the second access.

4. The method for establishing a multiple access protocol data unit session and user plane resources as claimed in claim 3, characterized in that: The user equipment starts data transmission through the second access type.

5. The method for establishing a multiple access protocol data unit session and user plane resources as claimed in claim 1, characterized in that: When receiving the protocol data unit session establishment accept message, the user equipment starts a timer, and when the timer expires, the user equipment re-initiates the protocol data unit session establishment process requested by the user equipment through the second access type.

6. A user equipment for establishing a multiple access protocol data unit session and user plane resources, comprising: a protocol data unit session processing circuit to establish a multiple access protocol data unit session, wherein the user equipment is registered with a public land mobile network via a first access type and a second access type; A radio frequency transceiver sends a protocol data unit session establishment request message through the first access type, and receives a protocol data unit session establishment acceptance message as a response; the user equipment considers that the multi-access protocol data unit session has been started and that user plane resources have been established on the first access, and when the protocol data unit session establishment acceptance message is received, the user equipment starts data transmission through the first access type.

7. The user equipment according to claim 6, characterized in that The protocol data unit session establishment accept message includes an access service control conversion split container resource element.

8. The user equipment according to claim 6, characterized in that The user equipment considers that user plane resources are subsequently established on the second access.

9. The user equipment according to claim 8, characterized in that The user equipment starts data transmission through the second access type.

10. The user equipment according to claim 6, characterized in that When receiving the protocol data unit session establishment accept message, the user equipment starts a timer, and when the timer expires, the user equipment re-initiates the protocol data unit session establishment process requested by the user equipment through the second access type.

11. A method for establishing a multiple access protocol data unit session and user plane resources, characterized in that: include: maintaining a single access protocol data unit session by a user equipment, wherein the user equipment is registered with a public land mobile network via a first access type and a second access type; A protocol data unit session modification request message is sent through the first access type to convert the single-access protocol data unit session into a multiple-access protocol data unit session, and a protocol data unit session modification command message is received in response, the user equipment considers that the session has been converted into the multiple-access protocol data unit session and considers that user plane resources have been established on the first access, and when the protocol data unit session modification command message is received, the user equipment starts data transmission through the first access type.

12. The method for establishing a multiple access protocol data unit session and user plane resources according to claim 11, characterized in that: The protocol data unit session modification command message includes an access service control conversion split container resource element.

13. The method for establishing a multiple access protocol data unit session and user plane resources according to claim 11, characterized in that: The user equipment considers that user plane resources are subsequently established on the second access.

14. The method for establishing a multiple access protocol data unit session and user plane resources according to claim 13, characterized in that: The user equipment starts data transmission through the second access type.

15. The method for establishing a multiple access protocol data unit session and user plane resources according to claim 11, characterized in that: When receiving the protocol data unit session modification command message, the user equipment starts a timer, and when the timer expires, the user equipment re-initiates the protocol data unit session establishment process requested by the user equipment through the second access type.

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