Non-access stratum synchronization

Abstract

Embodiments of the present invention relate to a network node and a network access node for addressing NAS mismatches between a network and a client device. The scheme of the invention considers all NAS processes currently used for indicating parameter change or state change in the client device. The NAS process may be network initiated, or may be initiated by a client device. To resolve NAS mismatches, a DL NAS message or a UL NAS message may terminate the NAS procedure. In addition, embodiments of the invention also relate to corresponding methods and computer programs.

Description

Technical Field

[0001] Embodiments of the present invention relate to network nodes and network access nodes for non-access stratum (NAS) synchronization. Furthermore, embodiments of the present invention also relate to corresponding methods and computer programs. Background Technology

[0002] In the traditional 3GPP paging mechanism, the user equipment (UE) calculates the paging occasion (PO) in the paging frame (PF). The PO calculation is based on the UE's identifier. Details of this PO calculation are specified in 3GPP TS 38.304.

[0003] Due to the limited capacity of the paging channel, multiple UEs may be assigned to the same paging channel. The UE receives downlink control information (DCI), and the paging message is scrambled by the paging radio network temporary identifier (P-RNTI). The paging DCI and the paging message are always transmitted in the same time slot. Currently, only one P-RNTI is defined and shared by all UEs. Summary of the Invention

[0004] One objective of embodiments of the present invention is to provide a solution for reducing or solving the disadvantages and problems of conventional solutions.

[0005] The above and other objectives are achieved through the subject matter of the independent claims. Further embodiments of the invention are provided in the dependent claims.

[0006] According to a first aspect of the invention, the above and other objectives are achieved through a network node, the network node being used for:

[0007] Transmit downlink non-access stratum (NAS) transmission messages to network access nodes, wherein the downlink NAS transmission messages include NAS messages of NAS procedures between the network node and client devices and indications of NAS transmission status requests indicating the NAS messages;

[0008] Receive NAS transmission report messages from the network access node, wherein the NAS transmission report messages indicate the NAS transmission status of the NAS messages.

[0009] The advantage of the network node described in the first aspect is that it provides a universal solution for NAS synchronization, applicable to all NAS processes initiated by the network and client devices, and not specific to any particular scenario. Furthermore, since only the network needs to be upgraded to support this universal solution without affecting legacy client devices, it is applicable to all previously released client devices.

[0010] In one implementation of the network node according to the first aspect, the network node is used for:

[0011] When the NAS transmission status is successful, apply the NAS configuration of the NAS message.

[0012] The advantage of this implementation is that the network node applies the new NAS configuration to the client device only when the NAS transfer status is successful, ensuring that there is no status / configuration mismatch between the client device and the network node.

[0013] In one implementation of the network node according to the first aspect, the network node is used for:

[0014] When the NAS transmission status fails, the downlink NAS transmission message is retransmitted to the network access node.

[0015] The advantage of this implementation is that network nodes will know that NAS messages have not yet been transmitted to client devices and will take appropriate actions to retransmit downlink NAS transmission messages.

[0016] In one implementation of the network node according to the first aspect, the NAS transmission status request and / or the NAS transmission status are indicated by a flag.

[0017] The advantage of this implementation is that it minimizes the signaling overhead of the introduced information cells (i.e., NAS transmission status request and NAS transmission status).

[0018] In one implementation of the network node according to the first aspect, the network node is part of the core network.

[0019] The advantage of this implementation is that it provides a general mechanism that can be used to increase the reliability of signaling between any two network nodes.

[0020] In one implementation of the network node according to the first aspect, the network node is an AMF.

[0021] According to a second aspect of the invention, the above and other objectives are achieved through a network access node, which is used to:

[0022] Receive downlink NAS transmission messages from the network node, wherein the downlink NAS transmission messages include NAS messages of the NAS process between the network node and the client device and an indication of a NAS transmission status request indicating the NAS messages;

[0023] Based on the NAS transmission status request, determine the NAS transmission status of the NAS message;

[0024] A NAS transmission report message is transmitted to the network node, wherein the NAS transmission report message indicates the determined NAS transmission status of the NAS message.

[0025] The advantage of the network access node described in the second aspect is that it provides a universal solution for NAS synchronization, applicable to all NAS processes initiated by the network and client devices, and not specific to any particular scenario. Furthermore, since only the network needs to be upgraded to support this universal solution without affecting traditional client devices, it is applicable to all previously released client devices.

[0026] In one implementation of the network access node according to the second aspect, the network access node is used for:

[0027] The NAS transmission status is determined based on the acknowledgment or RRC transmission report message at the PDCP / RLC layer.

[0028] PDCP can be understood as Packet Data Convergence Protocol, and RLC can be understood as Radio Link Control.

[0029] The advantage of this implementation is that the network access node can ensure that the message is delivered to the client device based on PDCP / RLC layer acknowledgment or RRC transmission report message.

[0030] In one implementation of the network access node according to the second aspect, the NAS transmission status is either successful or failed.

[0031] In one implementation of the network access node according to the second aspect, the network access node is used for:

[0032] When the NAS transmission status fails, the downlink NAS transmission message is received again from the network node.

[0033] The advantage of this implementation is that network nodes will know that NAS messages have not yet been transmitted to client devices and will take appropriate actions to retransmit downlink NAS transmission messages.

[0034] In one implementation of the network access node according to the second aspect, the NAS transmission status request and / or the NAS transmission status are indicated by a flag.

[0035] The advantage of this implementation is that it minimizes the signaling overhead of the introduced information cells (i.e., NAS transmission status request and NAS transmission status).

[0036] In one implementation of the network access node according to the second aspect, the network access node is part of a wireless access network.

[0037] In one implementation of the network access node according to the second aspect, the network access node is a gNB.

[0038] According to a third aspect of the invention, the above and other objectives are achieved by a method for a network node, the method comprising:

[0039] Transmit downlink NAS transmission messages to network access nodes, wherein the downlink NAS transmission messages include NAS messages of the NAS process between the network node and the client device and an indication of a NAS transmission status request indicating the NAS messages;

[0040] Receive NAS transmission report messages from the network access node, wherein the NAS transmission report messages indicate the NAS transmission status of the NAS messages.

[0041] The method described in the third aspect can be extended to an implementation corresponding to the network node implementation described in the first aspect. Therefore, the implementation of the method includes one or more features of the corresponding implementation of the network node.

[0042] The advantages of the method described in the third aspect are the same as the advantages of the corresponding implementation of the network node described in the first aspect.

[0043] According to a fourth aspect of the invention, the above and other objectives are achieved by a method for a network access node, the method comprising:

[0044] Receive downlink NAS transmission messages from the network node, wherein the downlink NAS transmission messages include NAS messages of the NAS process between the network node and the client device and an indication of a NAS transmission status request indicating the NAS messages;

[0045] Based on the NAS transmission status request, determine the NAS transmission status of the NAS message;

[0046] A NAS transmission report message is transmitted to the network node, wherein the NAS transmission report message indicates the determined NAS transmission status of the NAS message.

[0047] The method described in the fourth aspect can be extended to an implementation corresponding to the network access node implementation described in the second aspect. Therefore, the implementation of the method includes one or more features of the corresponding implementation of the network access node.

[0048] The advantages of the method described in the fourth aspect are the same as those of the corresponding implementation of the network access node described in the second aspect.

[0049] According to a fifth aspect of the invention, the above and other objectives are achieved through a network node, the network node being used for:

[0050] Transmit downlink NAS transmission messages to network access nodes, wherein the downlink NAS transmission messages indicate the expected NAS messages of the NAS process between the network node and the client device;

[0051] Receive an uplink NAS transmission message from the network access node, wherein the uplink NAS transmission message includes a NAS message from the client device and indicates a NAS transmission status request for the NAS message from the client device;

[0052] Based on the NAS transmission status request, a NAS transmission report message is transmitted to the network access node, wherein the NAS transmission report message indicates the NAS transmission status of the NAS message from the client device.

[0053] The advantage of the network node described in the fifth aspect is that it provides a universal solution applicable to all NAS processes initiated by the network and client devices, without being specific to any particular scenario. Furthermore, since only the network needs to be upgraded to support this universal solution without affecting legacy client devices, it is applicable to all previously released client devices.

[0054] In one implementation of the network node according to the fifth aspect, the network node is used for:

[0055] When the NAS transmission status of the NAS message from the client device is successful, the NAS configuration is applied upon receiving the NAS message from the client device.

[0056] The advantage of this implementation is that the network node applies the NAS configuration to the client device only when the NAS transfer status is successful, ensuring that there is no status / configuration mismatch between the client device and the network node.

[0057] In one implementation of the network node according to the fifth aspect, the network node is used for:

[0058] When the NAS transmission status of the NAS message from the client device is failed, the uplink NAS transmission message is received again from the network access node.

[0059] The advantage of this implementation is that network nodes will know that NAS messages have not yet been transmitted to client devices and will take appropriate actions to retransmit downlink NAS transmission messages.

[0060] In one implementation of the network node according to the fifth aspect, the expected NAS message and / or the NAS transmission status request and / or the NAS transmission status are indicated by a flag.

[0061] The advantage of this implementation is that it minimizes the signaling overhead of the introduced information elements (i.e., expected NAS messages, NAS delivery status requests, and NAS delivery status).

[0062] In one implementation of the network node according to the fifth aspect, the network node is part of the core network.

[0063] The advantage of this implementation is that it provides a general mechanism that can be used to increase the reliability of signaling between any two network nodes.

[0064] In one implementation of the network node according to the fifth aspect, the network node is an AMF.

[0065] According to a sixth aspect of the invention, the above and other objectives are achieved through a network access node, the network access node being configured to:

[0066] Receive downlink NAS transmission messages from the network node, wherein the downlink NAS transmission messages indicate the expected NAS messages of the NAS process between the network node and the client device;

[0067] Based on the expected NAS message, an uplink NAS transmission message is transmitted to the network node, wherein the uplink NAS transmission message includes a NAS message from the client device and indicates a NAS transmission status request for the NAS message from the client device;

[0068] Receive a NAS transmission report message from the network node, wherein the NAS transmission report message indicates the NAS transmission status of the NAS message from the client device.

[0069] The advantage of the network access node described in the sixth aspect is that it provides a universal solution applicable to all NAS processes initiated by the network and client devices, without being specific to any particular scenario. Furthermore, since only the network needs to be upgraded to support this universal solution without affecting legacy client devices, it is applicable to all previously released client devices.

[0070] In one implementation of the network access node according to the sixth aspect, the NAS transmission status is successful.

[0071] In one implementation of the network access node according to the sixth aspect, the network access node is used for:

[0072] When the NAS transmission status fails, the uplink NAS transmission message is retransmitted to the network node.

[0073] The advantage of this implementation is that network nodes will know that NAS messages have not yet been transmitted to client devices and will take appropriate actions to retransmit downlink NAS transmission messages.

[0074] In one implementation of the network access node according to the sixth aspect, the expected NAS message and / or the NAS transmission status request and / or the NAS transmission status are indicated by a flag.

[0075] The advantage of this implementation is that it minimizes the signaling overhead of the introduced information elements (i.e., expected NAS messages, NAS delivery status requests, and NAS delivery status).

[0076] In one implementation of the network access node according to the sixth aspect, the network access node is part of a wireless access network.

[0077] In one implementation of the network access node according to the sixth aspect, the network access node is a gNB.

[0078] According to a seventh aspect of the present invention, the above and other objectives are achieved by a method for a network node, the method comprising:

[0079] Transmit downlink NAS transmission messages to network access nodes, wherein the downlink NAS transmission messages indicate the expected NAS messages of the NAS process between the network node and the client device;

[0080] Receive an uplink NAS transmission message from the network access node, wherein the uplink NAS transmission message includes a NAS message from the client device and indicates a NAS transmission status request for the NAS message from the client device;

[0081] Based on the NAS transmission status request, a NAS transmission report message is transmitted to the network access node, wherein the NAS transmission report message indicates the NAS transmission status of the NAS message from the client device.

[0082] The method described in the seventh aspect can be extended to an implementation corresponding to the network node implementation described in the fifth aspect. Therefore, the implementation of the method includes one or more features of the corresponding implementation of the network node.

[0083] The advantages of the method described in the seventh aspect are the same as those of the corresponding implementation of the network node described in the fifth aspect.

[0084] According to an eighth aspect of the present invention, the above and other objectives are achieved by a method for a network access node, the method comprising:

[0085] Receive downlink NAS transmission messages from the network node, wherein the downlink NAS transmission messages indicate the expected NAS messages of the NAS process between the network node and the client device;

[0086] Based on the expected NAS message, an uplink NAS transmission message is transmitted to the network node, wherein the uplink NAS transmission message includes a NAS message from the client device and indicates a NAS transmission status request for the NAS message from the client device;

[0087] Receive a NAS transmission report message from the network node, wherein the NAS transmission report message indicates the NAS transmission status of the NAS message from the client device.

[0088] The method described in the eighth aspect can be extended to an implementation corresponding to the network access node implementation described in the sixth aspect. Therefore, the implementation of the method includes one or more features of the corresponding implementation of the network access node.

[0089] The advantages of the method described in the eighth aspect are the same as those of the corresponding implementation of the network access node described in the sixth aspect.

[0090] Embodiments of the present invention also relate to a computer program including program code that, when executed by at least one processor, causes the at least one processor to perform any of the methods described in embodiments of the present invention. Furthermore, embodiments of the present invention also relate to a computer program product comprising a computer-readable medium and a computer program, wherein the computer program is included in the computer-readable medium and may include one or more of the following: read-only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), flash memory, electrically erasable PROM (EEPROM), hard disk drive, etc.

[0091] Other applications and advantages of embodiments of the present invention will become apparent from the following detailed description. Attached Figure Description

[0092] The accompanying drawings are intended to illustrate and explain different embodiments of the invention, in which:

[0093] - Figure 1 A network node according to an embodiment of the present invention is shown;

[0094] - Figure 2 A flowchart of a method for a network node according to an embodiment of the present invention is shown;

[0095] - Figure 3 A flowchart of a method for a network node according to an embodiment of the present invention is shown;

[0096] - Figure 4 A network access node according to an embodiment of the present invention is shown;

[0097] - Figure 5 A flowchart of a method for a network access node according to an embodiment of the present invention is shown;

[0098] - Figure 6 A flowchart of a method for a network access node according to an embodiment of the present invention is shown;

[0099] - Figure 7 A communication system according to an embodiment of the present invention is shown;

[0100] - Figure 8 and Figure 9 Signaling diagrams illustrating various aspects of the present invention are shown;

[0101] - Figure 10 and Figure 11Signaling diagrams illustrating other aspects of the invention are shown. Detailed Implementation

[0102] It has been observed that occasional paging loss occurs in 5G networks. Initially, this was thought to be caused by a mismatch in discontinuous reception (DRX) cycles between the UE and the network. However, subsequent detailed analysis revealed that the problem stems from a mismatch between the UE's stored PEI with paging subgrouping (PEIPS) information and the network's paging subgrouping information.

[0103] From a more general perspective, paging loss is caused by a state / configuration mismatch between the UE and the access and mobility management function (AMF). Although some mechanisms exist, including configuring the Radio Link Control (RLC) layer in Acknowledgment mode (AM) for the Signaling Radio Bearer (SRB) 2 over the air interface, and configuring a "NAS non-delivery indication" procedure on the NG interface to notify the AMF of NAS message delivery issues, NAS message loss does indeed occur in real-world scenarios, leading to a state / configuration mismatch between the UE and the AMF. The NAS layer manages the establishment of communication sessions and maintains continuous communication with the UE while the UE is mobile.

[0104] Therefore, this paper discloses a scheme that aims to provide a general network-based solution to the UE / AMF mismatch problem and is also applicable to all previous versions of the UE.

[0105] Figure 1 A network node 100 according to an embodiment of the present invention is shown. Figure 1 In the illustrated embodiment, network node 100 includes a processor 102, a transceiver 104, and a memory 106. The processor 102 is coupled to the transceiver 104 and the memory 106 via a communication component 108 known in the art. Network node 100 can be used for wired communication in a communication system. Wired communication capability can be provided via a wired communication interface 110 (e.g., coupled to transceiver 104).

[0106] Processor 102 may be referred to as one or more general-purpose central processing units (CPUs), one or more digital signal processors (DSPs), one or more application-specific integrated circuits (ASICs), one or more field-programmable gate arrays (FPGAs), one or more programmable logic devices, one or more discrete gates, one or more transistor logic devices, one or more discrete hardware components, or one or more chipsets. Memory 106 may be read-only memory, random access memory (RAM), or non-volatile RAM (NVRAM). Transceiver 104 may be transceiver circuitry, a power controller, or an interface providing the ability to communicate with other communication modules or communication devices (e.g., network nodes and network servers). Transceiver 104, memory 106, and / or processor 102 may be implemented in separate chipsets or in a common chipset.

[0107] In this disclosure, network node 100 performing certain operations can be understood to mean that network node 100 includes suitable components for performing these operations, such as processor 102 and transceiver 104.

[0108] According to an embodiment of the present invention, a network node 100 according to a first aspect of the present invention is configured to: transmit a downlink NAS transmission message 510 to a network access node 300, wherein the downlink NAS transmission message 510 includes a NAS message of a NAS process between the network node 100 and a client device 600 and an indication of a NAS transmission status request for the NAS message; and receive a NAS transmission report message 520 from the network access node 300, wherein the NAS transmission report message 520 indicates the NAS transmission status of the NAS message.

[0109] Furthermore, in one embodiment of the present invention, the network node 100 according to the first aspect of the present invention includes a transceiver configured to: transmit a downlink NAS transmission message 510 to a network access node 300, wherein the downlink NAS transmission message 510 includes a NAS message of a NAS process between the network node 100 and the client device 600 and an indication of a NAS transmission status request for the NAS message; and receive a NAS transmission report message 520 from the network access node 300, wherein the NAS transmission report message 520 indicates the NAS transmission status of the NAS message.

[0110] Furthermore, in another embodiment of the present invention, the network node 100 according to the first aspect of the present invention includes a processor and a memory, the memory storing computer-readable instructions, which, when executed by the processor, cause the processor to: transmit a downlink NAS transmission message 510 to the network access node 300, wherein the downlink NAS transmission message 510 includes a NAS message of a NAS process between the network node 100 and the client device 600 and an indication of a NAS transmission status request for the NAS message; and receive a NAS transmission report message 520 from the network access node 300, wherein the NAS transmission report message 520 indicates the NAS transmission status of the NAS message.

[0111] According to an embodiment of the present invention, a network node 100 according to a fifth aspect of the present invention is configured to: transmit a downlink NAS transmission message 510 to a network access node 300, wherein the downlink NAS transmission message 510 indicates an expected NAS message for a NAS process between the network node 100 and a client device 600; receive an uplink NAS transmission message 530 from the network access node 300, the uplink NAS transmission message 530 including a NAS message from the client device 600 and indicating a NAS transmission status request for the NAS message from the client device 600; and transmit a NAS transmission report message 520 to the network access node 300 based on the NAS transmission status request, wherein the NAS transmission report message 520 indicates the NAS transmission status of the NAS message from the client device 600.

[0112] Furthermore, in one embodiment of the present invention, the network node 100 according to the fifth aspect of the present invention includes a transceiver configured to: transmit a downlink NAS transmission message 510 to a network access node 300, wherein the downlink NAS transmission message 510 indicates an expected NAS message for a NAS process between the network node 100 and the client device 600; receive an uplink NAS transmission message 530 from the network access node 300, the uplink NAS transmission message 530 including a NAS message from the client device 600 and indicating a NAS transmission status request for the NAS message from the client device 600; and transmit a NAS transmission report message 520 to the network access node 300 based on the NAS transmission status request, wherein the NAS transmission report message 520 indicates the NAS transmission status of the NAS message from the client device 600.

[0113] Furthermore, in another embodiment of the present invention, the network node 100 according to the fifth aspect of the present invention includes a processor and a memory storing computer-readable instructions that, when executed by the processor, cause the processor to: transmit a downlink NAS transmission message 510 to the network access node 300, wherein the downlink NAS transmission message 510 indicates an expected NAS message for a NAS process between the network node 100 and the client device 600; receive an uplink NAS transmission message 530 from the network access node 300, the uplink NAS transmission message 530 including a NAS message from the client device 600 and indicating a NAS transmission status request for the NAS message from the client device 600; and transmit a NAS transmission report message 520 to the network access node 300 based on the NAS transmission status request, wherein the NAS transmission report message 520 indicates the NAS transmission status of the NAS message from the client device 600.

[0114] Figure 2 A flowchart of a method 200 according to a third aspect of the present invention is shown, which can be implemented at a network node 100 (e.g., Figure 1 The method is executed in the network node 100 shown. Method 200 includes: transmitting a downlink NAS transmission message 510 to the network access node 300, wherein the downlink NAS transmission message 510 includes a NAS message of a NAS procedure between the network node 100 and the client device 600 and an indication of a NAS transmission status request for the NAS message; and receiving a NAS transmission report message 520 from the network access node 300, wherein the NAS transmission report message 520 indicates the NAS transmission status of the NAS message.

[0115] Figure 3 A flowchart of a method 200' according to a seventh aspect of the present invention is shown, the method 200' being implemented at a network node 100 (e.g., Figure 1 The method is executed in the network node 100 shown. Method 200' includes: transmitting a 202' downlink NAS transmission message 510 to the network access node 300, wherein the downlink NAS transmission message 510 indicates an expected NAS message for a NAS process between the network node 100 and the client device 600; receiving a 204' uplink NAS transmission message 530 from the network access node 300, the uplink NAS transmission message 530 including a NAS message from the client device 600 and indicating a NAS transmission status request for the NAS message from the client device 600; and transmitting a 206' NAS transmission report message 520 to the network access node 300 based on the NAS transmission status request, wherein the NAS transmission report message 520 indicates the NAS transmission status of the NAS message from the client device 600.

[0116] Figure 4 A network access node 300 according to an embodiment of the present invention is shown. Figure 4 In the illustrated embodiment, network access node 300 includes a processor 302, a transceiver 304, and a memory 306. The processor 302 is coupled to the transceiver 304 and the memory 306 via a communication component 308 known in the art. Network access node 300 also includes a communication interface 310 coupled to the transceiver 304, indicating that network access node 300 is used for communication within a communication system.

[0117] Processor 302 may be referred to as one or more general-purpose CPUs, one or more DSPs, one or more ASICs, one or more FPGAs, one or more programmable logic devices, one or more discrete gates, one or more transistor logic devices, one or more discrete hardware components, or one or more chipsets. Memory 306 may be read-only memory, RAM, or NVRAM. Transceiver 304 may be transceiver circuitry, a power controller, or an interface providing the ability to communicate with other communication modules or communication devices. Transceiver 304, memory 306, and / or processor 302 may be implemented in separate chipsets or in a common chipset.

[0118] In this disclosure, the network access node 300 performing certain operations can be understood to mean that the network access node 300 includes suitable components for performing these operations, such as processor 302 and transceiver 304.

[0119] According to an embodiment of the present invention, a network access node 300 according to a second aspect of the present invention is configured to: receive a downlink NAS transmission message 510 from a network node 100, wherein the downlink NAS transmission message 510 includes a NAS message of a NAS process between the network node 100 and a client device 600 and an indication of a NAS transmission status request indicating the NAS message; determine the NAS transmission status of the NAS message based on the NAS transmission status request; and transmit a NAS transmission report message 520 to the network node 100, wherein the NAS transmission report message 520 indicates the determined NAS transmission status of the NAS message.

[0120] Furthermore, in one embodiment of the present invention, the network access node 300 according to the second aspect of the present invention includes a transceiver configured to: receive a downlink NAS transmission message 510 from the network node 100, wherein the downlink NAS transmission message 510 includes a NAS message of a NAS procedure between the network node 100 and the client device 600 and an indication of a NAS transmission status request indicating the NAS message. The network access node 300 includes a processor configured to: determine the NAS transmission status of the NAS message based on the NAS transmission status request. The transceiver is further configured to: transmit a NAS transmission report message 520 to the network node 100, wherein the NAS transmission report message 520 indicates the determined NAS transmission status of the NAS message.

[0121] Furthermore, in another embodiment of the present invention, the network access node 300 according to the second aspect of the present invention includes a processor and a memory, the memory storing computer-readable instructions, which, when executed by the processor, cause the processor to: receive a downlink NAS transmission message 510 from the network node 100, wherein the downlink NAS transmission message 510 includes a NAS message of a NAS process between the network node 100 and the client device 600 and an indication of a NAS transmission status request indicating the NAS message; determine the NAS transmission status of the NAS message based on the NAS transmission status request; and transmit a NAS transmission report message 520 to the network node 100, wherein the NAS transmission report message 520 indicates the determined NAS transmission status of the NAS message.

[0122] Figure 5 A flowchart of a method 400 according to a fourth aspect of the present invention is shown, which can be performed in a network access node 300. The method 400 includes: receiving a downlink NAS transmission message 510 from a network node 100, wherein the downlink NAS transmission message 510 includes a NAS message of a NAS procedure between the network node 100 and a client device 600 and an indication of a NAS transmission status request indicating the NAS message; determining a NAS transmission status of the NAS message based on the NAS transmission status request; and transmitting a NAS transmission report message 520 to the network node 100, wherein the NAS transmission report message 520 indicates the determined NAS transmission status of the NAS message.

[0123] Figure 6A flowchart of a method 400' according to an eighth aspect of the present invention is shown, which can be performed in a network access node 300. Method 400' includes: receiving a 402' downlink NAS transmission message 510 from a network node 100, wherein the downlink NAS transmission message 510 indicates an expected NAS message for a NAS procedure between the network node 100 and a client device 600; transmitting a 404' uplink NAS transmission message 530 to the network node 100 based on the expected NAS message, wherein the uplink NAS transmission message 530 includes a NAS message from the client device 600 and indicates a NAS transmission status request for the NAS message from the client device 600; and receiving a 406' NAS transmission report message 520 from the network node 300, wherein the NAS transmission report message 520 indicates the NAS transmission status of the NAS message from the client device 600.

[0124] Figure 7 A communication system 500 according to an embodiment of the present invention is illustrated. The communication system 500 in the disclosed embodiment includes a network node 100 and a network access node 300, which are used for communication and operation within the communication system 500. The network node 100 may be an AMF (Advanced Feature Provider), while the network access node 300 may be a base station of a RAN (Radio Router). The network node 100 and the network access node 300 may communicate with each other using a suitable communication interface. The network access node 300 may also be used to communicate with a client device 600, for example, via a standardized air interface, which may be represented as downlink (DL) communication and uplink (UL) communication.

[0125] Further details relating to embodiments of the invention are referenced in 3GPP 5G. Figures 8 to 11 The signaling diagram shown is used for description. Therefore, the terminology, definitions, expressions, and system architectures from 3GPP 5G can be used. Thus, the mentioned diagram illustrates a signaling diagram including a network node 100 serving as the AMF 100 (CN), a network access node 300 serving as the RAN and represented as NG-RAN 300, and a client device 600 serving as the UE 600. However, it should be noted that embodiments of the present invention are not limited thereto.

[0126] NAS procedures can generally be categorized as network-initiated or UE-initiated, and are terminated based on UL NAS messages or DL ​​NAS messages. This invention addresses all NAS procedures currently used to indicate parameter changes or state changes in UE 600. Figure 8 The diagram illustrates the NAS procedure initiated by the UE, where the DL NAS message completes / terminates the NAS procedure. Figure 9This illustrates a network-initiated NAS process, where DL NAS messages complete / terminate the NAS process. On the other hand, Figure 10 This illustrates the NAS procedure initiated by the UE, where the UL NAS message completes / terminates the NAS procedure. Figure 11 The diagram illustrates a network-initiated NAS process, where UL NAS messages complete / terminate the NAS process. Therefore, based on the type of message carrying the NAS configuration and the type of message completing / terminating the NAS process, a general scheme for reliable delivery of these NAS messages can be provided for NAS synchronization.

[0127] Figure 8 The NAS procedure initiated by the UE is shown, in which the DL NAS message completes / terminates the NAS procedure.

[0128] exist Figure 8 In step 1, UE 600 transmits a UL information transmission message containing a UL NAS message to NG-RAN 300. The UL NAS message is the initial NAS message in the NAS process between UE 600 and AMF 100.

[0129] exist Figure 8 In step 2, NG-RAN 300 transmits a UL NAS transmission message to AMF 100. The UL NAS transmission message initiates the NAS procedure between UE 600 and AMF 100.

[0130] exist Figure 8 In step 3, AMF 100 decides to change the NAS information / parameters and sends a DL NAS message (not shown in the figure) to UE 600.

[0131] exist Figure 8 In step 4, AMF 100 transmits DL NAS transmission message 510 to NG-RAN 300. DL NAS transmission message 510 includes a NAS message for the NAS procedure between AMF 100 and UE 600, and also includes an indication of a NAS transmission status request indicating the NAS message.

[0132] exist Figure 8 In step 5, NG-RAN 300 transmits a DL information transmission message containing DL NAS messages to UE 600.

[0133] exist Figure 8In step 6, the NG-RAN 300 determines the NAS transmission status based on PDCP / RLC layer acknowledgment, or, in the case of a split RAN architecture, based on an RRC transmission report message on the F1 interface. For example, the NG-RAN receives an RLC acknowledgment (ACK) of the DL NAS message and determines whether the NAS message has been transmitted to the UE 600. Alternatively, in the case of a split RAN architecture, an RRC transmission report message from the F1 interface of the distributed unit (DU) should indicate that the NAS message was successfully transmitted to the centralized unit (CU) of the NG-RAN.

[0134] The NAS transmission status can be either successful or failed. Success indicates that the DL NAS message has been successfully transmitted to UE600.

[0135] exist Figure 8 In step 7, the UE 600 applies the NAS information / parameter changes and adopts the new NAS configuration from the DL NAS message.

[0136] exist Figure 8 In step 8, NG-RAN 300 transmits NAS transmission report message 520 to AMF 100, wherein NAS transmission report message 520 indicates the NAS transmission status of NAS message.

[0137] exist Figure 8 In step 9, when the NAS transmission status is successful, the AMF 100 applies the NAS configuration from the NAS message. The AMF 100 can also indicate any NAS configuration-related information to the NG-RAN 300 for use by the NG-RAN 300.

[0138] However, if the NAS transmission status fails, the AMF 100 retransmits the downlink NAS transmission message 510 (not shown in the figure) to the NG-RAN 300. Therefore, when the NAS transmission status fails, the NG-RAN 300 will receive the DLNAS transmission message 510 from the AMF 100 again.

[0139] NAS transfer status requests and / or NAS transfer status indications can be indicated by flags such as bit flags.

[0140] exist Figure 8 In step 10, UE 600 and AMF 100 are synchronized in terms of status / configuration, thus minimizing the possibility of NAS status or configuration mismatch.

[0141] Figure 9The diagram illustrates a network-initiated NAS process, where a DL NAS message completes or terminates the NAS process. Figure 9 Steps 2 to 8 in the middle Figure 8 Steps 4 through 10 are the same. Therefore, with Figure 8 The difference between the two schemes lies in Figure 9 Step 1, in which AMF 100 (instead of UE 600) initiates the NAS process between UE 600 and AMF 100 by deciding to change NAS information / parameters and sending a DL NAS message to UE 600.

[0142] Therefore, in Figure 8 and Figure 9 In the illustrated scheme, the DL NAS message carries critical NAS configuration, which also completes / terminates the NAS process between AMF 100 and UE 600. For example, this means:

[0143] It is recommended to add a new information element (IE) defining "NAS transfer status request" to the critical DL NAS transfer messages for changing NAS status / configuration.

[0144] The iiAMF 100 can be configured with the new IE "NAS Transmission Status Request" to request transmission reports from the NG-RAN 300.

[0145] The iiiNG-RAN 300 returns a new NAS transfer report message indicating the "NAS transfer status".

[0146] Only after this will AMF 100 apply the new configuration / state to the UE 600 in question to ensure that there is no NAS state / configuration mismatch between UE600 and AMF 100.

[0147] Figure 10 The NAS procedure initiated by the UE is shown, in which the UL NAS message completes / terminates the NAS procedure.

[0148] exist Figure 10 In step 1, UE 600 transmits a UL information transmission message containing a UL NAS message to NG-RAN 300. The UL NAS message is the initial NAS message in the NAS process between UE 600 and AMF 100.

[0149] exist Figure 10 In step 2, NG-RAN 300 transmits a UL NAS transmission message to AMF 100. The UL NAS transmission message initiates the NAS procedure between UE 600 and AMF 100.

[0150] exist Figure 10 In step 3, AMF 100 decides to change the NAS information / parameters, therefore sends a DL NAS message to UE 600 and determines that the UL NAS message is expected to be terminated, and the new NAS parameters / information will be applied after that.

[0151] exist Figure 10 In step 4, AMF 100 transmits DL NAS transmission message 510 to NG-RAN 300. DL NAS transmission message 510 indicates the expected NAS message for the NAS procedure between AMF 100 and UE 600.

[0152] exist Figure 10 In step 5, NG-RAN transmits a DL information transmission message containing DL NAS messages to UE 600.

[0153] exist Figure 10 In step 6, UE 600 transmits a UL information transmission message containing the UL NAS message back to NG-RAN 300.

[0154] exist Figure 10 In step 7, NG-RAN 300 transmits UL NAS transmission message 530 to AMF 100. UL NAS transmission message 530 includes a NAS message from UE 600 and also indicates a NAS transmission status request for the NAS message from UE 600.

[0155] If the NAS transmission status is successful, the NG-RAN 300 does not need to perform any further operations. However, if the NAS transmission status is failed, the NG-RAN 300 retransmits the uplink NAS transmission message 530 (not shown in the figure) to the AMF 100.

[0156] exist Figure 10 In step 8, when AMF 100 receives a NAS message from UE 600 and the NAS transmission status of the NAS message from UE 600 is successful, it applies the NAS configuration of the downlink NAS transmission message 510.

[0157] AMF 100 can optionally check whether a NAS message from UE 600 is an expected NAS message. This check is only intended to handle the exceptional situation where UE 600 initiates a new NAS procedure, i.e., when the current procedure cannot be completed by sending a UL response message, but instead sends a NAS message to initiate another procedure.

[0158] As described above, when the NAS transmission status of the NAS message from UE 600 is failed, or when there is no response from AMF 100 within a certain period of time, AMF 100 will receive the uplink NAS transmission message 530 from NG-RAN 300 again.

[0159] exist Figure 10 In step 9, AMF 100 transmits a NAS transmission report message 520 to NG-RAN 300 based on the NAS transmission status request received in UL NAS transmission message 530. The NAS transmission report message 520 indicates the NAS transmission status of the NAS message from UE 600.

[0160] Expected NAS messages and / or NAS delivery status requests and / or NAS delivery status can be indicated by flags such as flag bits.

[0161] exist Figure 10 In step 10, the UE 600 applies key NAS information / parameters and adopts the new NAS configuration in use.

[0162] exist Figure 10 In step 11, AMF 100 applies the NAS parameters / configuration of the NAS message and also indicates to NG-RAN 300 any NAS configuration-related information to be used by NG-RAN 300.

[0163] exist Figure 10 In step 12, UE 600 and AMF 100 are synchronized in terms of state / configuration, thus minimizing the possibility of NAS state or configuration mismatch.

[0164] Figure 11 The diagram illustrates a network-initiated NAS process, where a UL NAS message completes / terminates the NAS process. Figure 11 Steps 2 to 10 in the middle and Figure 10 Steps 4 through 12 are the same. Therefore, with Figure 10 The difference between the two schemes lies in Figure 11 In step 1, the AMF 100 decides to initiate the NAS process and sends a DL NAS message, expecting a UL NAS message as a response or acknowledgment.

[0165] Therefore, in Figure 10 and Figure 11 In the illustrated scheme, the DL NAS message carries critical NAS configuration, and the UL NAS message completes / terminates the NAS process between AMF 100 and UE 600. For example, this means:

[0166] When a DL NAS message is sent to NG-RAN 300 using a DL NAS transmission message (which is an intermediate or initial NAS message in the NAS process between AMF 100 and UE 600), AMF 100 indicates that a UL NAS message is required (which terminates the NAS process) via the new IE “Expected UL NAS Message”.

[0167] ii recommends adding the new IE "NAS Transfer Status Request" to the critical UL NAS transfer messages for changing NAS status / configuration.

[0168] iii. Upon receiving a critical UL NAS message, the NG-RAN 300 sends a UL NAS message to the AMF 100 in the UL NAS transmission message and sets a new IE "NAS Transmission Status Request" in the UL NAS message to request a transmission report from the AMF 100.

[0169] The ivAMF 100 checks whether the UL NAS message is the expected response and sends a new NAS delivery report message to the NG-RAN 300 to receive the ULNAS message.

[0170] Only after this will the AMF 100 apply the new configuration / state to the UE 600 in question to ensure that there is no state / configuration mismatch between the UE 600 and the AMF 100.

[0171] If AMF 100 does not send a response to NG-RAN 300, NG-RAN 300 can resend the UL NAS message to AMF 100 and set the NAS transfer status request.

[0172] In this paper, network node 100 can also be represented as an AMF in a communication system or any corresponding network function.

[0173] The network access node 300 in this document can also be referred to as a wireless network access node, access network access node, access point (AP), or base station (BS), such as a radio base station (RBS). In some networks, it may be called a transmitter, "gNB," "gNodeB," "eNB," "eNodeB," "NodeB," or "B node," depending on the standards, technologies, and terminology used. Depending on the transmission power and cell size, wireless network access nodes can have different categories or types, such as macro eNodeB, home eNodeB, or pico base station. A wireless network access node can also be a site, which is any device containing IEEE 802.11-compliant media access control (MAC) and physical layer (PHY) interfaces to the wireless medium (WM). Wireless network access nodes can be used to communicate in the following: 3GPP related long term evolution (LTE), LTE-Advanced, fifth generation (5G) wireless systems, such as new radio (NR) and its evolution, and IEEE related Wi-Fi, worldwide interoperability for microwave access (WiMAX) and its evolution.

[0174] In this document, the client device 600 can refer to user equipment (UE / userdevice), a mobile station, an internet of things (IoT) device, a sensor device, a wireless terminal, and / or a mobile terminal capable of wireless communication in a wireless communication system (sometimes also called a cellular wireless system). The UE can also be a wirelessly capable mobile phone, cellular phone, tablet, or laptop. The UE here can be a portable, pocket-sized, handheld, computer-configurable, or vehicle-mounted mobile device capable of transmitting voice and / or data with other communication entities (e.g., other receivers or servers) via a radio access network (RAN). The UE can also be a site, which is any device containing IEEE 802.11 compliant MAC and PHY interfaces to WM. The UE can be used to communicate in: 3GPP-related LTE, Advanced LTE, 5G wireless systems (e.g., NR) and their evolutions, and IEEE-related Wi-Fi, WiMAX and their evolutions.

[0175] Furthermore, any method according to embodiments of the present invention can be implemented in a computer program having code components that, when run by a processing component, cause the processing component to perform the steps of the method. The computer program is included in a computer-readable medium of the computer program product. The computer-readable medium can substantially include any memory, such as the previously mentioned ROM, PROM, EPROM, flash memory, EEPROM, or hard disk drive.

[0176] Furthermore, it should be recognized that network node 100 and network access node 300 include the necessary communication capabilities in the form of functions, components, units, elements, etc., for performing or implementing embodiments of the present invention. Examples of other such components, units, elements, and functions include: processors, memories, buffers, control logic, encoders, decoders, rate matchers, rate dematchers, mapping units, multipliers, decision units, selection units, switches, interleavers, deinterleavers, modulators, modems, inputs, outputs, antennas, amplifiers, receiving units, transmitting units, DSPs, TCM encoders, TCM decoders, power supply units, power feeders, communication interfaces, communication protocols, etc., which are suitably arranged together to execute the scheme.

[0177] Therefore, one or more processors in network node 100 and network access node 300 may include one or more instances of a CPU, processing unit, processing circuit, processor, ASIC, microprocessor, or other processing logic capable of interpreting and executing instructions. Thus, the term "processor" can refer to a processing circuit comprising multiple processing circuits, such as any, some, or all of the aforementioned processing circuits. This processing circuit can also perform data processing functions for data input, output, and processing, including data buffering and device control functions, such as call processing control, user interface control, etc.

[0178] Finally, it should be understood that the present invention is not limited to the embodiments described above, but also relates to and incorporates all embodiments within the scope of the appended independent claims.

Claims

1. A network node (100), characterized in that, Used for: Transmit a downlink non-access stratum NAS transmission message (510) to a network access node (300), wherein the downlink NAS transmission message (510) includes a NAS message of a NAS procedure between the network node (100) and the client device (600) and an indication of a NAS transmission status request indicating the NAS message. Receive NAS transmission report message (520) from the network access node (300), wherein the NAS transmission report message (520) indicates the NAS transmission status of the NAS message.

2. The network node (100) according to claim 1, characterized in that, Used for: When the NAS transmission status is successful, apply the NAS configuration of the NAS message.

3. The network node (100) according to claim 1 or 2, characterized in that, Used for: When the NAS transmission status fails, the downlink NAS transmission message (510) is retransmitted to the network access node (300).

4. The network node (100) according to any one of the preceding claims, characterized in that, The NAS transfer status request and / or the NAS transfer status are indicated by flags.

5. The network node (100) according to any one of the preceding claims, characterized in that, The network node (100) is part of the core network.

6. The network node (100) according to claim 5, characterized in that, The network node (100) is an AMF.

7. A network access node, characterized in that, Used for: Receive downlink NAS transmission messages (510) from network node (100), wherein the downlink NAS transmission messages (510) include NAS messages of NAS procedures between network node (100) and client device (600) and an indication of NAS transmission status request indicating the NAS messages; Based on the NAS transmission status request, determine the NAS transmission status of the NAS message; A NAS transmission report message (520) is transmitted to the network node (100), wherein the NAS transmission report message (520) indicates the determined NAS transmission status of the NAS message.

8. The network access node (300) according to claim 7, characterized in that, Used for: The NAS transmission status is determined based on the acknowledgment or RRC transmission report message at the PDCP / RLC layer.

9. The network access node (300) according to claim 7 or 8, characterized in that, The NAS transmission status is either successful or failed.

10. The network access node (300) according to claim 9, characterized in that, Used for: When the NAS transmission status fails, the downlink NAS transmission message (510) is received again from the network node (100).

11. The network access node (300) according to any one of claims 7 to 10, characterized in that, The NAS transmission status request and / or the NAS transmission status are indicated by flags.

12. The network access node (300) according to any one of claims 7 to 11, characterized in that, The network access node (300) is part of the wireless access network.

13. The network access node (300) according to claim 12, characterized in that, The network access node (300) is a gNB.

14. A method (200) for a network node (100), characterized in that, The method (200) includes: Transmit (202) a downlink non-access stratum NAS transmission message (510) to the network access node (300), wherein the downlink NAS transmission message (510) includes a NAS message of a NAS procedure between the network node (100) and the client device (600) and an indication of a NAS transmission status request indicating the NAS message; Receive (204) NAS transmission report message (520) from the network access node (300), wherein the NAS transmission report message (520) indicates the NAS transmission status of the NAS message.

15. A method (400) for a network access node (300), characterized in that, The method (400) includes: Receive (402) downlink NAS transmission message (510) from network node (100), wherein the downlink NAS transmission message (510) includes a NAS message of a NAS process between the network node (100) and the client device (600) and an indication of a NAS transmission status request indicating the NAS message; Based on the NAS transmission status request, determine (404) the NAS transmission status of the NAS message; Transmit (406) NAS transmission report message (520) to the network node (100), wherein the NAS transmission report message (520) indicates the determined NAS transmission status of the NAS message.

16. A computer program, characterized in that, Includes program code, which, when the computer program is run on a computer, is used to perform the method according to claim 14 or 15.

17. A network node (100), characterized in that, Used for: Transmit a downlink NAS transmission message (510) to a network access node (300), wherein the downlink NAS transmission message (510) indicates the expected NAS message of the NAS procedure between the network node (100) and the client device (600); Receive an uplink NAS transmission message (530) from the network access node (300), wherein the uplink NAS transmission message (530) includes a NAS message from the client device (600) and indicates a NAS transmission status request for the NAS message from the client device (600). Based on the NAS transmission status request, a NAS transmission report message (520) is transmitted to the network access node (300), wherein the NAS transmission report message (520) indicates the NAS transmission status of the NAS message from the client device (600).

18. The network node (100) according to claim 17, characterized in that, Used for: When the NAS transmission status of the NAS message from the client device (600) is successful, the NAS configuration is applied upon receiving the NAS message from the client device (600).

19. The network node (100) according to claim 17 or 18, characterized in that, Used for: When the NAS transmission status of the NAS message from the client device (600) is a failure, the uplink NAS transmission message (530) is received again from the network access node (300).

20. The network node (100) according to any one of claims 17 to 19, characterized in that, The expected NAS message and / or the NAS transmission status request and / or the NAS transmission status are indicated by flags.

21. The network node (100) according to any one of claims 17 to 20, characterized in that, The network node (100) is part of the core network.

22. The network node (100) according to claim 21, characterized in that, The network node (100) is an AMF.

23. A network access node (300), characterized in that, Used for: Receive a downlink NAS transmission message (510) from a network node (100), wherein the downlink NAS transmission message (510) indicates the expected NAS message of the NAS procedure between the network node (100) and the client device (600); Based on the expected NAS message, an uplink NAS transmission message (530) is transmitted to the network node (100), wherein the uplink NAS transmission message (530) includes a NAS message from the client device (600) and indicates a NAS transmission status request for the NAS message from the client device (600). Receive a NAS transmission report message (520) from the network node (300), wherein the NAS transmission report message (520) indicates the NAS transmission status of the NAS message from the client device (600).

24. The network access node (300) according to claim 23, characterized in that, The NAS transfer status is successful.

25. The network access node (300) according to claim 23 or 24, characterized in that, Used for: When the NAS transmission status fails, the uplink NAS transmission message (530) is retransmitted to the network node (100).

26. The network access node (300) according to any one of claims 23 to 25, characterized in that, The expected NAS message and / or the NAS transmission status request and / or the NAS transmission status are indicated by flags.

27. The network access node (300) according to any one of claims 23 to 26, characterized in that, The network access node (300) is part of the wireless access network.

28. The network access node (300) according to claim 27, characterized in that, The network access node (300) is a gNB.

29. A method (200') for a network node (100), characterized in that, The method (200') includes: Transmit (202') a downlink NAS transmission message (510) to the network access node (300), wherein the downlink NAS transmission message (510) indicates the expected NAS message of the NAS procedure between the network node (100) and the client device (600); Receive (204') an uplink NAS transmission message (530) from the network access node (300), wherein the uplink NAS transmission message (530) includes a NAS message from the client device (600) and indicates a NAS transmission status request for the NAS message from the client device (600); Based on the NAS transmission status request, a NAS transmission report message (520) is transmitted (206') to the network access node (300), wherein the NAS transmission report message (520) indicates the NAS transmission status of the NAS message from the client device (600).

30. A method (400') for a network access node (300), characterized in that, The method (400') includes: Receive (402') a downlink NAS transmission message (510) from network node (100), wherein the downlink NAS transmission message (510) indicates the expected NAS message of the NAS process between the network node (100) and the client device (600); Based on the expected NAS message, an uplink NAS transmission message (530) is transmitted (404') to the network node (100), wherein the uplink NAS transmission message (530) includes a NAS message from the client device (600) and indicates a NAS transmission status request for the NAS message from the client device (600). Receive (406') NAS transmission report message (520) from the network node (300), wherein the NAS transmission report message (520) indicates the NAS transmission status of the NAS message from the client device (600).

31. A computer program, characterized in that, Includes program code, which, when the computer program is run on a computer, is used to perform the method according to claim 29 or 30.

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