Enhanced processing method for process conflict and user equipment

Abstract

An enhanced method and user equipment for handling conflicts between a UE-requested PDU Session Establishment procedure and a network-requested PDU Session Release procedure are proposed. When the PDU Session Establishment Request message indicates that the UE-requested PDU Session Establishment Request procedure is to switch an existing PDU session between 5G 3GPP access and 5G non-3GPP access, the UE continues the network-requested PDU Session Release procedure and aborts the UE-requested PDU Session Establishment procedure. Otherwise, the UE ignores the received PDU Session Release Command message and continues the UE-requested PDU Session Establishment procedure.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority under 35 U.S.C. §119 to U.S. Provisional Application No. 63 / 187,447, filed on May 12, 2021, entitled “Enhanced Handling of 5GSM Process Conflicts,” the subject matter of which is incorporated herein by reference. Technical Field

[0003] The disclosed embodiments relate generally to wireless communications, and more particularly to methods for handling conflicts in 5G session management (5GSM) protocol data unit (PDU) session establishment procedures and PDU session release procedures. 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 simplified network architecture. LTE systems, also known as 4G systems, also provide seamless integration with older wireless networks such as GSM, CDMA, and universal mobile telecommunication systems (UMTS). In LTE systems, the evolved universal terrestrial radio access network (E-UTRAN) includes multiple evolved Node-Bs (eNode / eNB) that communicate with multiple mobile stations called user equipment (UE). The 3rd generation partner project (3GPP) network typically includes a mix of 2G / 3G / 4G systems. The Next Generation Mobile Network (NGMN) committee has decided to focus future NGMN activities on defining the end-to-end requirements for 5G new radio (NR) systems.

[0005] In 5G / NR, a PDU session defines the association between the UE and the data network that provides the PDU connection service. PDU session establishment is a parallel process to the PDN connection (bearer) process in 4G / LTE. Each PDU session is identified by a PDU session ID (PSI) and may include multiple 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 through a non-3GPP RAN). Both the network and the UE can initiate different PDU session processes, such as the PDU session establishment process, the PDU session modification process, and the PDU session release process, to manage the PDU session.

[0006] When a conflict occurs between the UE-requested PDU session establishment procedure and the network-requested PDU session release procedure, the UE shall generally ignore the PDU session release command message and continue with the UE-requested PDU session establishment procedure. However, the PDU session establishment procedure can be used for different purposes, including initial request, existing PDU session, initial emergency request, existing emergency PDU session, and MA PDU request. The corresponding handling of conflicts in different scenarios should be differentiated.

[0007] Seek solutions. Summary of the Invention

[0008] A method for handling a conflict between a UE-requested PDU session establishment procedure and a network-requested PDU session release procedure is proposed. If the UE receives a PDU session release command message after sending a PDU session establishment request (PDU SESSION ESTABLISHMENT REQUEST) message to the network, and the PDU session ID (PSI) in the PDU session release command message is the same as the PDU session establishment request message PSI, a conflict is detected. When the request type of the PDU session establishment request message indicates that the PDU session establishment request procedure requested by the UE is to switch an existing PDU session between 5G 3GPP access and 5G non-3GPP access, the UE continues the network-requested PDU session release procedure and terminates the UE-requested PDU session establishment procedure. Otherwise, the UE ignores the PDU session release command message and continues the UE-requested PDU session establishment procedure.

[0009] In one embodiment, the UE sends a PDU session establishment request message in a 5G system (5G system, 5GS) to initiate a UE-requested PDU session establishment process. The UE receives a PDU session release command message for a network-requested PDU session release process, wherein the PSI in the received PDU session release command message is the same as the PSI in the sent PDU session establishment request message. The UE determines the release condition based on whether the UE-requested PDU session establishment process is to switch the existing PDU session. When the release condition is met, the UE continues with the network-requested PDU session release process, wherein the UE terminates the UE-requested PDU session establishment process. Otherwise, when the condition is not met, the UE ignores the PDU session release command message. In one embodiment, when the PDU session establishment request message contains a request type indicating that the UE-requested PDU session establishment request process is to switch an existing PDU session between 5G 3GPP access and 5G non-3GPP access, the UE determines that the release condition is met and releases the PDU session.

[0010] According to the enhanced processing method and user equipment for process conflicts provided by the present invention, conflicts between a PDU session establishment process and a network-requested PDU session release process can be processed accordingly for different scenarios.

[0011] 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

[0012] The accompanying drawings, wherein like numerals represent like components, illustrate embodiments of the present invention.

[0013] Figure 1 An exemplary 5G network supporting PDU session management and a method for PDU session process conflict handling according to one novel aspect are shown.

[0014] Figure 2 A simplified block diagram of a UE and a network entity according to an embodiment of the present invention is shown.

[0015] Figure 3 One embodiment of a PDU session establishment process when the UE also receives a PDU session release command from the network according to one novel aspect is shown.

[0016] Figure 4 Another embodiment of a PDU session establishment process when the UE also receives a PDU session release command from the network according to one novel aspect is shown.

[0017] Figure 5 is a flowchart of a method for handling PDU session process conflicts according to one novel aspect of the present invention. DETAILED DESCRIPTION

[0018] Reference will now be made in detail to some embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

[0019] Figure 1 An exemplary 5G network 100 supporting PDU session management and a method for PDU session process conflict handling according to one novel aspect is illustrated. The 5G NR network 100 includes a UE 101, a 3GPP access 102 (e.g., a 3GPP RAN), a non-3GPP access 103 (e.g., a non-3GPP RAN), 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) 113, and a 5G core (5GC) data network 120. The AMF 110 communicates with a base station in the 3GPP access 102, the SMF 111, and the UPF 113 for access and mobility management of wireless access devices in the 5G network 100. The SMF 111 is primarily responsible for interacting with the decoupled data plane, creating, updating, and removing PDU sessions and managing session contexts with the UPF 113. The N3IWF 112 interfaces with the 5G core network control plane functions and is responsible for routing messages outside the 5G RAN.

[0020] In the Access Stratum (AS) layer, the RAN provides radio access to UE 101 via a radio access technology (RAT). In the Non-Access Stratum (NAS) layer, the AMF 110 and SMF 111 communicate with the RAN and 5GC for access and mobility management of wireless access devices in the 5G network 100, as well as PDU session management. 3GPP access 102 may include base stations (gNBs or eNBs) providing radio access to UE 101 via various 3GPP RATs, including 5G, 4G, and 3G / 2G. Non-3GPP access 103 may include access points (APs) providing radio access to UE 101 via non-3GPP RATs, including WiFi. UE 101 can obtain access to the data network 120 through 3GPP access 102, AMF 110, SMF 111, and UPF 113. UE 101 can obtain access to data network 120 through non-3GPP access 103, N3IWF 112, AMF 110, SMF 111 and UPF 113. UE 101 can be equipped with a single radio frequency (RF) module or transceiver or multiple RF modules or transceivers for services via different RATs / CNs. In some examples, UE 101 can be a smartphone, a wearable device, an Internet of Things (IoT) device, a tablet, etc.

[0021] The 5GS network is a packet-switched (PS) Internet Protocol (IP) network. When a UE joins an evolved packet system (EPS) network, a packet data network (PDN) address (i.e., an address that can be used on the PDN) is assigned to the UE to connect to the PDN. In 4G, EPS defines a default EPS bearer to provide always-on IP connectivity. In 5G, the PDU session establishment process is a parallel process to the PDN connection process in 4G. The PDU session defines the association between the UE and the data network that provides the PDU connection service. Each PDU session is identified by a PDU session ID and can be established on a 3GPP RAN and / or on a non-3GPP RAN for radio access. 5GSM for PDU sessions for 3GPP access and non-3GPP access is managed by the AMF and SMF through NAS signaling. In 5G, a multi-access (MA) PDU session uses one 3GPP access network or one non-3GPP access network at a time, or uses one 3GPP access network and one non-3GPP access network simultaneously.

[0022] Both the network and the UE can initiate different PDU session procedures, such as the PDU session establishment procedure, the PDU session modification procedure, and the PDU session release procedure, to manage the PDU session. When the PDU session establishment procedure requested by the UE and the PDU session release procedure requested by the network conflict, generally, the UE should ignore the PDU session release command message and continue with the PDU session establishment procedure requested by the UE. However, the PDU session establishment procedure can be used for different purposes, including initial requests, existing PDU sessions, initial emergency requests, existing emergency PDU sessions, and MA PDU requests. The corresponding handling of conflicts in different scenarios should be distinguished.

[0023] According to a novel aspect, a clear UE behavior is proposed to handle the conflict of the UE-requested PDU Session Establishment Procedure and the network-requested PDU Session Release Procedure (as shown in 130). If the UE 101 receives a PDU Session Release Command message after sending a PDU Session Establishment Request message to the network, and the PDU Session ID in the PDU Session Release Command message is the same as the PDU Session ID in the PDU Session Establishment Request message, a conflict is detected. If the UE-requested PDU Session Establishment Procedure is used to switch an existing PDU session between 5G 3GPP and 5G non-3GPP access, as shown in 140, the UE 101 continues with the network-requested PDU Session Release Procedure to release the PDU session, aborts the UE-requested PDU Session Establishment Procedure, stops timer T3580, releases the allocated PTI, and enters the state PROCEDURE TRANSACTION INACTIVE. Otherwise, as shown in 150, the UE 101 ignores the PDU Session Release Command message and continues with the UE-requested PDU Session Establishment Procedure.

[0024] 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 shown. The network entity 211 can be a base station and / or an AMF / SMF. The network entity 211 has an antenna 215 for transmitting and receiving radio signals. A radio frequency (RF) transceiver module 214 coupled to the antenna receives RF signals from the antenna 215, converts them into baseband signals and sends the baseband signals to the processor 213. The RF transceiver 214 also converts the baseband signals received from the processor 213 into 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 base station 211. The memory 212 includes volatile computer-readable storage media and non-volatile computer-readable storage media, storing program instructions and data 220 to control the operation of the base station 211. In Figure 2For example, in the example of , the network entity 211 also includes a protocol stack 280 and a set of control function modules and circuits 290. The protocol stack 280 includes a NAS layer for communicating with the AMF / SMF / MME entity connected to the core network, a Radio Resource Control (RRC) layer for high-level configuration and control, a Packet Data Convergence Protocol / Radio Link (PDCP / RLC) layer, a Media Access Control (MAC) layer, and a Physical (PHY) layer. In one example, the control function modules and circuits 290 include a PDU session processing circuit 291 that handles the PDU establishment, modification, and release processes, and a configuration and control circuit 292 that provides different parameters to configure and control the UE, including mobility management and PDU session management related functions.

[0025] Similarly, UE 201 has a memory 202, a processor 203, and an RF transceiver module 204. RF transceiver 204 is coupled to antenna 205, receives RF signals from antenna 205, converts them into baseband signals, and transmits the baseband signals to processor 203. RF transceiver 204 also converts baseband signals received from processor 203, converts them into RF signals, and transmits them to antenna 205. Processor 203 processes the received baseband signals and invokes various functional modules and circuits to perform functions in UE 201. Memory 202 includes volatile computer-readable storage media and non-volatile computer-readable storage media, and stores data and program instructions 210 to be executed by the processor to control the operation of UE 201. Suitable processors include, for example, a dedicated processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), and other types of integrated circuits (ICs) and / or state machines. The processor, in conjunction with software, may be used to implement and configure features of the UE 201.

[0026] UE 201 also includes a protocol stack 260 and a set of control functional modules and circuits 270. Protocol stack 260 includes a NAS layer for communicating with the AMF / SMF / MME entity connected to the core network, an RRC layer for high-level configuration and control, a PDCP / RLC layer, a MAC layer, and a PHY layer. The control functional modules and circuits 270 can be implemented and configured using software, firmware, hardware, and / or a combination thereof. The control functional modules and circuits, when executed by a processor via program instructions contained in a memory, cooperate with each other to enable UE 201 to perform the embodiments and functional tasks and features in the network.

[0027] In one example, the control function module and circuit 270 includes a PDU session processing circuit 271 that performs PDU session establishment, modification, and release procedures with the network, and a configuration and control circuit 272 that processes configuration and control parameters for mobility management and session management. Upon detecting a conflict between a UE-requested PDU session establishment procedure and a network-requested PDU session release procedure, the UE decides whether to continue the network-requested PDU session release procedure and abort the UE-requested PDU session establishment procedure, or ignore the PDU session release command message and continue the UE-requested PDU session establishment procedure.

[0028] Figure 3 An embodiment of a PDU session establishment process according to a novel aspect is shown when the UE also receives a PDU session release command from the network. In step 311, the UE 301 establishes and / or maintains one or more PDU sessions. For example, one of the PDU sessions with PSI=5 is established between the UE 301 and the 5GS network through a 3GPP access type or through a non-3GPP access type. In step 321, the UE 301 triggers a UE-requested PDU session establishment procedure by sending a PDU session establishment request message for the PDU session (PSI=5) on other, for example, non-3GPP access type or 3GPP access type. In step 322, the UE 301 receives a PDU session release command message for the same PDU session (PSI=5) after triggering the UE-requested PDU session establishment procedure but before the UE-requested PDU session establishment procedure is completed. Therefore, the UE 301 detects a conflict between the UE-requested PDU session establishment procedure and the network-requested PDU session release procedure. A conflict is detected when UE 301 receives a PDU session release command message after sending a PDU session establishment request message to the network, and the PDU session ID in the PDU session release command message is the same as the PDU session ID in the PDU session establishment request message.

[0029] Normally, when a conflict is detected, the UE should ignore the PDU Session Release Command message and continue with the UE-requested PDU Session Establishment procedure. The reason is that the PDU Session Release Command message may be a retransmission or an error from the network and is invalid, so the UE should continue with the UE-requested PDU Session Establishment procedure. However, the PDU Session Establishment procedure can be used for different purposes: 1) initial request; 2) existing PDU session; 3) initial emergency request; 4) existing emergency PDU session; 5) MA PDU request. In most cases, the UE should ignore the PDU Session Release Command message, especially when the UE wants to establish a new PDU Session. However, in some other cases, the UE may want to use the PDU Session Establishment procedure to switch an existing PDU Session. Therefore, the network may indeed intend to release the existing PDU Session, so the UE should continue with the PDU Session Release procedure and abort the PDU Session Establishment procedure.

[0030] In step 331, UE 301 determines whether the corresponding processing of the detected conflict satisfies the release condition. If the PDU session establishment request message is sent with the request type set to "existing PDU session" or "existing emergency PDU session" to switch an existing PDU session between 3GPP access and non-3GPP access (e.g., PSI=5), the release condition is met. Therefore, UE 301 continues the network-requested PDU session release procedure and aborts the PDU session establishment procedure. Therefore, in step 341, UE 301 continues the network-requested PDU session release procedure to release the PDU session (PSI=5). In step 342, UE 301 sends a PDU session release completion message to 5GS. In step 351, UE 301 aborts the UE-requested PDU session establishment procedure, stops timer T3580, releases the allocated PTI, and enters the process transaction inactive state. The order of steps 341 , 342 and 351 may be different, for example, step 351 may be performed first by UE 301 , followed by steps 341 and 342 .

[0031] Figure 4Another embodiment of processing PDU session establishment when the UE also receives a PDU session release command from the network according to a novel aspect is shown. In step 411, UE 401 establishes and / or maintains one or more PDU sessions. For example, one of the PDU sessions with PSI=5 is established between UE 401 and the 5GS network via a 3GPP access type or via a non-3GPP access type. In step 421, UE 401 triggers a UE-requested PDU session establishment procedure by sending a PDU session establishment request message on a non-3GPP access type for the PDU session (e.g., PSI=6). In step 422, UE 401 receives a PDU session release command message for the same PDU session (PSI=6) after triggering the UE-requested PDU session establishment procedure but before the UE-requested PDU session establishment procedure is completed. Therefore, UE 401 detects a conflict between the UE-requested PDU session establishment procedure and the network-requested PDU session release procedure. A conflict is detected when UE 401 receives a PDU Session Release Command message after sending a PDU Session Establishment Request message to the network, and the PDU Session ID in the PDU Session Release Command message is the same as the PDU Session ID in the PDU Session Establishment Request message.

[0032] As previously mentioned Figure 3 As explained, when a conflict is detected, the UE needs to determine how to handle the conflict based on the release condition. In step 431, the UE 401 determines whether the release condition satisfies the corresponding handling of the detected conflict. In the first case, if the PDU session establishment request message is sent with a request type set to "initial request", "initial emergency request" or "MA PDU request" in order to establish a new PDU session with PSI=6, the release condition is not met. In the second case, if the PDU session establishment request message is sent with a request type set to "existing PDU session" or "existing emergency PDU session" in order to switch an existing PDU session (e.g., PSI=5) between a PDN connection (S1 mode or ePDG) and a 5G PDU session (N1 mode), the release condition is not met.

[0033] When the UE determines that the release condition is not met, for example, the network-requested PDU session release may be a retransmission or an error, the UE should ignore the release command message. Therefore, UE 401 continues the UE-requested PDU session establishment process and does not perform the network-requested PDU session release process. As a result, in step 441, UE 401 decides to ignore the PDU session release command message for releasing the PDU session. In step 451, UE 401 decides to continue the UE-requested PDU session establishment process. In step 452, a new PDU session (e.g., PSI=6) is established between UE 401 and 5GS via 3GPP and / or non-3GPP access type.

[0034] Figure 5 1 is a flowchart of a method for processing PDU session establishment according to a novel aspect of the present invention. In step 501, the UE sends a PDU Session Establishment Request message in the 5GS to initiate a UE-requested PDU session establishment procedure. In step 502, the UE receives a PDU Session Release Command message for a network-requested PDU session release procedure, wherein the PSI in the received PDU Session Release Command message is the same as the PSI in the sent PDU Session Establishment Request message. In step 503, the UE determines a release condition based on whether the UE-requested PDU session establishment procedure is to switch an existing PDU session. In step 504, when the release condition is met, the UE proceeds with the network-requested PDU session release procedure, wherein the UE aborts the UE-requested PDU session establishment procedure. In step 505, when the release condition is not met, the UE ignores the PDU Session Release Command message. In one embodiment, the UE determines that the release condition is met when the PDU Session Establishment Request message includes a request type, where the request type indicates that the UE-requested PDU session establishment request procedure is to switch an existing PDU session between 5G 3GPP access and 5G non-3GPP access.

[0035] Although the present invention has been described in conjunction with certain specific embodiments for guiding purposes, it is not limited thereto. Therefore, various modifications, amendments and combinations of the various features of the described embodiments may be implemented without departing from the scope of the invention as set forth in the claims.

Claims

1. A method for enhancing the handling of process conflicts, comprising: A user equipment in the 5G system sends a protocol data unit (PDU) session establishment request message to initiate a PDU session establishment process requested by the user equipment; Receiving a PDU session release command message for a network-requested PDU session release procedure, wherein the PDU session ID (PSI) in the received PDU session release command message is the same as the PSI in the sent PDU session establishment request message; Determining a release condition based on whether the PDU session establishment process requested by the user equipment is to switch an existing PDU session; as well as When the release condition is met, the PDU session release process requested by the network is continued, wherein the user equipment terminates the PDU session establishment process requested by the user equipment; otherwise, When the release condition is not met, the PDU session release command message is ignored.

2. The method according to claim 1, characterized in that The PDU session establishment request message carries a request type, where the request type indicates whether the request is an initial request or for an existing PDU session.

3. The method according to claim 2, characterized in that The release condition is met when the request type indicates that the PDU session establishment request process requested by the user equipment is to switch an existing PDU session between 5G 3GPP access and 5G non-3GPP access.

4. The method according to claim 1, wherein The network-requested PDU session release process includes the user equipment sending a PDU session release completion message or a 5G session management status message to the 5G system.

5. The method according to claim 1, wherein The aborting the PDU session establishment process requested by the user equipment includes the user equipment stopping a timer T3580, releasing an allocated procedure transaction identifier (PTI), and entering a procedure transaction inactive state.

6. The method according to claim 2, characterized in that When the request type indicates that the PDU session establishment request process requested by the user equipment is to establish a new PDU session, the user equipment determines that the release condition is not met.

7. The method according to claim 2, characterized in that When the request type indicates that the PDU session establishment request process requested by the user equipment is to switch an existing PDU session from the S1 mode to the N1 mode, the user equipment determines that the release condition is not met.

8. The method according to claim 1, characterized in that When the release condition is not met, the user equipment continues the PDU session establishment process requested by the user equipment.

9. A user equipment for enhanced handling of process conflicts, comprising: A transmitter, configured to send a protocol data unit (PDU) session establishment request message in a 5G system to initiate a PDU session establishment process requested by a user equipment; a receiver, configured to receive a PDU session release command message for a network-requested PDU session release procedure, wherein the PDU session ID (PSI) in the received PDU session release command message is the same as the PSI in the sent PDU session establishment request message; The control circuit determines a release condition based on whether the PDU session establishment process requested by the user equipment is to switch the existing PDU session; as well as The PDU session processing circuit continues the PDU session release process requested by the network when the release condition is met, wherein the user equipment terminates the PDU session establishment process requested by the user equipment; otherwise, when the release condition is not met, the PDU session release command message is ignored.

10. The user equipment according to claim 9, wherein: The PDU session establishment request message carries a request type, where the request type indicates whether the request is an initial request or for an existing PDU session.

11. The user equipment according to claim 10, wherein: The release condition is met when the request type indicates that the PDU session establishment request process requested by the user equipment is to switch an existing PDU session between 5G 3GPP access and 5G non-3GPP access.

12. The user equipment according to claim 9, wherein: The network-requested PDU session release process includes the user equipment sending a PDU session release completion message or a 5G session management status message to the 5G system.

13. The user equipment according to claim 9, wherein: The aborting the PDU session establishment process requested by the user equipment includes the user equipment stopping a timer T3580, releasing an allocated procedure transaction identifier (PTI), and entering a procedure transaction inactive state.

14. The user equipment according to claim 10, wherein: When the request type indicates that the PDU session establishment request process requested by the user equipment is to establish a new PDU session, the user equipment determines that the release condition is not met.

15. The user equipment according to claim 10, wherein: When the request type indicates that the PDU session establishment request process requested by the user equipment is to switch an existing PDU session from the S1 mode to the N1 mode, the user equipment determines that the release condition is not met.

16. The user equipment according to claim 9, wherein: When the release condition is not met, the user equipment continues the PDU session establishment process requested by the user equipment.

17. A user equipment for enhanced handling of process conflicts, comprising: A processor is coupled to a memory, wherein the memory stores program instructions and data, and when the program instructions and data are executed by the processor, the user equipment performs the operation described in any one of the methods of claims 1-8.

18. A non-volatile computer-readable storage medium storing program instructions and data, which, when executed by a processor of a user device for enhanced processing of process conflicts, causes the user device to perform the operations described in any one of claims 1 to 8.

Images