Enhanced Signaling Method and User Equipment for a Session of Protocol Data Units

Abstract

An enhanced signaling method for an always-on protocol data unit session. A user equipment transmits a non-access stratum (NAS) request message to a mobile communication network, and the non-access stratum request message includes an always-on protocol data unit session requested (APSR) information element (IE). The user equipment receives a non-access stratum response message from the mobile communication network, which includes an always-on protocol data unit session indication (APSI) information element, and the always-on protocol data unit session indication information element includes a duration indicator. When the user equipment is indicated by the always-on protocol data unit session indicator that the establishment of the always-on protocol data unit session is not allowed, it starts a timer according to the duration indicator and re-transmits the non-access stratum request message to the mobile communication network when the timer expires.

Description

Technical Field

[0001] This application relates to mobile communication technologies, and particularly to an enhanced signaling method for an Always-on Protocol Data Unit (PDU) session. Background Art

[0002] In a general mobile communication environment, user equipment (UE) (or may be referred to as a mobile station (MS)) with wireless communication capabilities such as mobile phones, tablet computers, etc. can communicate with a mobile communication network to obtain voice and / or data services. The communication between the user equipment and the mobile communication network can be carried out through various radio access technologies (RAT), including: Global System for Mobile communications (GSM) technology, General Packet Radio Service (GPRS) technology, Enhanced Data rates for Global Evolution (EDGE) technology, Wideband Code Division Multiple Access (WCDMA) technology, Code Division Multiple Access 2000 (CDMA-2000) technology, Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) technology, Worldwide Interoperability for Microwave Access (WiMAX) technology, Long Term Evolution (LTE) technology, and Long Term Evolution-Advanced (LTE-A) technology, etc.

[0003] The above wireless access technologies each follow different mobile communication standards to provide a common protocol for different wireless devices to communicate with each other within the spans of urban, national, and / or global levels. In recent years, a new emerging mobile communication standard - 5G New Radio (NR) technology has gradually become popular. This technology is an improvement based on the long-term evolution technology standard formulated by the 3rd Generation Partnership Project (3GPP). Its goal is to provide better mobile broadband network access by improving spectrum utilization efficiency, reducing costs, and enhancing service quality.

[0004] According to the standard specification for 5G New Radio technology formulated by the 3rd Generation Partnership Project, when a user equipment connects to a 5G mobile communication network, it can establish one or more always-on protocol data unit sessions (for ease of understanding, hereinafter simply referred to as always-on PDU session). Generally speaking, always-on PDU session can be used for mobile services with multimedia or low-latency requirements. For example, services such as Vehicle-to-Everything (V2X) that require a large amount of data and low-latency requirements can utilize the always-on PDU session to provide the characteristics of long-term uninterrupted and quick network connection.

[0005] However, there may be the following problems in the control of the existing standard specification for always-on PDU session. First, the standard specification does not clearly regulate how the always-on PDU session established in the 5G mobile communication network should be disposed of when the user equipment leaves the 5G mobile communication network. Therefore, it may cause the established always-on PDU session to be idle and not effectively utilized, resulting in a waste of network resources. Second, after the user equipment sends a request to establish an always-on PDU session, the 5G mobile communication network may reply with an acceptance message and carry an indication in it to inform the user equipment that it is not allowed to establish an always-on PDU session. If the user equipment still has pending data or messages that need to be transmitted via the always-on PDU session, it will continuously attempt to retransmit the request. Frequent signaling exchanges will cause unnecessary power consumption of the user equipment and waste of network resources. Summary of the Invention

[0006] To solve the above problems, the present application proposes an enhanced signaling method for always-on PDU sessions, adding additional parameters to the existing protocol data unit session establishment / modification procedure to enable a retransmission waiting mechanism for protocol data unit session establishment / modification requests at the user equipment side and to set the lifecycle of always-on PDU sessions at the network side. Further explanation, the retransmission waiting mechanism can ensure that the user equipment must wait for a period of time before retransmitting the protocol data unit session establishment / modification request, avoiding frequent signaling exchanges; while the lifecycle mechanism can allow the network side to start counting down a period of time representing the lifecycle of the always-on PDU session when it detects that the user equipment has left the network (for example: the 5G signal becomes too poor, so it chooses to switch to other RAT connections, or the user manually switches RAT, etc.). If the user equipment has not connected back to the network when the countdown ends, the always-on PDU session can be released to avoid waste of network resources.

[0007] The first embodiment of the present application provides an enhanced signaling method for always-on protocol data unit sessions, applicable to a user equipment. The above enhanced signaling method includes: transmitting a non-access stratum (NAS) request message to a mobile communication network, where the non-access stratum request message includes an always-on protocol data unit session requested (APSR) information element (IE); receiving from the mobile communication network a non-access stratum response message including an always-on protocol data unit session indication (APSI) information element, where the always-on protocol data unit session indication information element includes a duration indicator; and in response to the always-on protocol data unit session indication indicating that an always-on protocol data unit session cannot be established, starting a timer according to the duration indicator and retransmitting the non-access stratum request message to the mobile communication network when the timer expires.

[0008] In one example of the above first embodiment, the non-access stratum request message is a PDU SESSION ESTABLISHMENT REQUEST message, and the non-access stratum response message is a PDU SESSION ESTABLISHMENT ACCEPT message. Alternatively, in another example, the non-access stratum request message is a PDU SESSION MODIFICATION REQUEST message, and the non-access stratum response message is a PDU SESSION MODIFICATION COMMAND message.

[0009] In one example of the above first embodiment, the enhanced signaling method further includes: determining whether there is pending data at the user equipment that needs to be transmitted via the always-on PDU session; wherein the timer is started when there is pending data that needs to be transmitted via the always-on PDU session.

[0010] In one example of the above first embodiment, the always-on PDU session request information element includes a first lifetime metric for requesting the mobile communication network to set a lifetime for the always-on PDU session; and the always-on PDU session metric information element includes a second lifetime metric for indicating whether the mobile communication network agrees to set the lifetime.

[0011] A second embodiment of the present application provides a user equipment, including a wireless transceiver and a controller. The wireless transceiver is configured to perform wireless transmission and reception with a mobile communication network. The controller, coupled to the wireless transceiver, is configured to perform: transmitting, via the wireless transceiver, a non-access stratum request message to the mobile communication network, wherein the non-access stratum request message includes an always-on PDU session request information element; receiving, via the wireless transceiver, from the mobile communication network a non-access stratum response message including an always-on PDU session metric information element, wherein the always-on PDU session metric information element includes a duration metric; and in response to the always-on PDU session metric indicating that an always-on PDU session is not allowed to be established, starting a timer according to the duration metric and re-transmitting the non-access stratum request message to the mobile communication network via the wireless transceiver when the timer expires.

[0012] In one example of the above second embodiment, the non-access stratum request message is a PDU session establishment request message for always-on, and the non-access stratum response message is a PDU session establishment acceptance message for always-on. Alternatively, in another example, the non-access stratum request message is a PDU session modification request message for always-on, and the non-access stratum response message is a PDU session modification command message for always-on.

[0013] In one example of the above second embodiment, the controller further determines whether there is pending data at the user equipment that needs to be transmitted via the PDU session for always-on; wherein the timer is started when there is pending data that needs to be transmitted via the PDU session for always-on.

[0014] In one example of the above second embodiment, the PDU session request information element for always-on includes a first lifecycle metric for requesting the mobile communication network to set a lifecycle for the PDU session for always-on; and the PDU session metric information element includes a second lifecycle metric for indicating whether the mobile communication network agrees to set the lifecycle.

[0015] A third embodiment of the present application provides an enhanced signaling method for a PDU session for always-on, applicable to a mobile communication network. The enhanced signaling method includes: receiving, from a user equipment, a non-access stratum request message including a PDU session request information element for always-on, wherein the PDU session request information element for always-on includes a first lifecycle metric for requesting the mobile communication network to set a lifecycle for a PDU session for always-on; transmitting, in response to the mobile communication network allowing the establishment of the PDU session for always-on, a first non-access stratum response message including a first PDU session metric information element for always-on, wherein the first PDU session metric information element for always-on includes, in addition to indicating the allowance of the establishment of the PDU session for always-on, a second lifecycle metric for indicating that the mobile communication network agrees to set the lifecycle; starting, in response to the user equipment leaving the mobile communication network, a timer associated with the lifecycle; and releasing the PDU session for always-on in response to the user equipment not reconnecting to the mobile communication network before the expiration of the timer.

[0016] In one example of the above third embodiment, the non-access stratum request message is a PDU session establishment request message for always-on, and the non-access stratum response message is a PDU session establishment acceptance message for always-on. Alternatively, in another example, the non-access stratum request message is a PDU session modification request message for always-on, and the non-access stratum response message is a PDU session modification instruction message for always-on.

[0017] In one example of the above third embodiment, the enhanced signaling method further includes: resetting the timer and maintaining the always-on PDU session in response to the user equipment reconnecting to the mobile communication network before the timer expires.

[0018] In one example of the above third embodiment, the enhanced signaling method further includes: transmitting a second non-access stratum response message including a second always-on PDU session metric information element in response to the mobile communication network not allowing the establishment of the always-on PDU session, where the second always-on PDU session metric information element includes a duration metric in addition to indicating that the establishment of the always-on PDU session is not allowed, and is used to indicate that the user equipment needs to wait for a period of time before retransmitting the non-access stratum request message.

[0019] Regarding other additional features and advantages of the present application, those skilled in the art can make some modifications and refinements based on the enhanced signaling method of the always-on PDU session disclosed in the implementation method of this case without departing from the spirit and scope of the present application. Description of the Drawings

[0020] Figure 1 is a schematic diagram of a wireless communication environment according to an embodiment of the present application.

[0021] Figure 2 is an architecture diagram of the user equipment 110 according to an embodiment of the present application.

[0022] Figure 3 is an architecture diagram of the core network functional entity according to an embodiment of the present application.

[0023] Figure 4 is a signaling message sequence chart (MSC) of the always-on PDU session according to an embodiment of the present application.

[0024] Figures 5A - 5B is a signaling message sequence chart of the always-on PDU session according to another embodiment of the present application.

[0025] Figure 6Flowchart of an enhanced signaling method for an always-on protocol data unit session according to an embodiment of the present application.

[0026] Figure 7 Flowchart of an enhanced signaling method for an always-on protocol data unit session according to another embodiment of the present application. Detailed implementation

[0027] This section describes the preferred manner of implementing the present application, aiming to illustrate the spirit of the present application rather than to limit the protection scope of the present application. It can be understood that words such as "including" and "comprising" used in this specification are used to indicate the existence of specific technical features, numerical values, method steps, operations, elements, and / or components, but do not exclude the addition of more technical features, numerical values, method steps, operations, elements, components, or any combination of the above.

[0028] Figure 1 Schematic diagram of a wireless communication environment according to an embodiment of the present application.

[0029] As Figure 1 shown, the wireless communication environment 100 includes a user equipment 110 and a mobile communication network 120, where the user equipment 110 can be wirelessly connected to the mobile communication network 120 and establish a protocol data unit session (e.g., always-on PDU session) to obtain various mobile services, including voice services and data services.

[0030] The user equipment 110 can be a smart phone, a wearable electronic device, a vehicle-mounted communication device, a tablet computer, a laptop computer, or any electronic computing device as long as it can support the radio access technology used by the mobile communication network 120.

[0031] The mobile communication network 120 includes an access network 121 and a core network 122. The access network 121 is used to process radio signals, support terminal radio protocols, and connect the user equipment 110 to the core network 122. The core network 122 is used to perform mobile management, network-side authentication, and interface with a public network (e.g., the Internet). Both the access network 121 and the core network 122 can each include one or more network nodes to perform the above functions.

[0032] In one embodiment, the mobile communication network 120 can be a 5G mobile communication network (e.g., a new radio network), and the access network 121 and the core network 122 can be a Next Generation - Radio Access Network (NG-RAN) and a Next Generation - Core Network (NG-CN), respectively.

[0033] The next-generation wireless access network may include one or more base stations, such as next-generation NodeBs (gNBs). Each next-generation base station may support wireless transmission in high frequency bands (e.g., bands above 24 gigahertz (GHz)), and each next-generation base station may further include one or more Transmission Reception Points (TRPs). Each next-generation base station or signal transceiver point can be regarded as a 5G base station.

[0034] Each 5G base station may form one or more cells to provide wireless access services to user equipment 110. For example, user equipment 110 may camp on one or more cells, and these cells may be referred to as serving cells.

[0035] The next-generation core network may include entities of multiple network functions, such as Access and Mobility Function (AMF), Session Management Function (SMF), Policy Control Function (PCF), Application Function (AF), Authentication Server Function (AUSF), User Plane Function (UPF), User Data Management (UDM), etc. In particular, the User Plane Function manages protocol data unit sessions (e.g., always-on PDU session) according to the instructions of the Session Management Function, including establishment, modification, release, etc.

[0036] It should be noted that one feature of this application is to enhance the existing protocol data unit session establishment / modification procedure, and add additional parameters to enable a retransmission waiting mechanism for protocol data unit session establishment / modification requests at the user equipment side, and set the life cycle of the always-on PDU session at the network side. In this way, through the retransmission waiting mechanism, it can be ensured that the user equipment must wait for a period of time before retransmitting the protocol data unit session establishment / modification request, thereby avoiding frequent signaling exchanges. In addition, through the life cycle mechanism, the network side can be allowed to start counting down a period of time representing the life cycle of the always-on PDU session when it detects that the user equipment leaves the network (for example: the 5G signal becomes too poor, so it chooses to switch to other RAT connections, or the user manually switches the RAT, etc.). If the user equipment still has not connected back to the network when the countdown ends, the always-on PDU session can be released to avoid waste of network resources.

[0037] Figure 2 It is an architecture diagram of the user equipment 110 according to an embodiment of this application.

[0038] As Figure 2 shown, the user equipment 110 may include a wireless transceiver 10, a controller 20, a storage device 30, a display device 40, and an input / output (I / O) device 50.

[0039] The wireless transceiver 10 is used to perform wireless transmission and reception with the mobile communication network 120 using a wireless access technology.

[0040] Specifically, the wireless transceiver 10 may include a baseband processing device 11, a radio frequency (RF) device 12, and an antenna 13, where the antenna 13 may include an antenna array for beamforming.

[0041] The baseband processing device 11 may include multiple hardware elements for performing baseband signal processing, including analog-to-digital conversion (ADC) / digital-to-analog conversion (DAC), gain adjustment, modulation and demodulation, and encoding / decoding, etc.

[0042] The radio frequency device 12 can receive radio frequency wireless signals through the antenna 13, convert the radio frequency wireless signals into baseband signals for further processing by the baseband processing device 11, or receive baseband signals from the baseband processing device 11 and convert the baseband signals into radio frequency wireless signals for transmission through the antenna 13. The radio frequency device 12 may also include multiple hardware components to perform the above conversion of radio frequency wireless signals. For example, the radio frequency device 12 may include a mixer to multiply the baseband signal by a radio frequency oscillation carrier, where the radio frequency can be 900 megahertz (MHz), 2100 megahertz, or 2.6 gigahertz used by 4G mobile communication technologies (such as: Long-Term Evolution / Long-Term Evolution Advanced / Time Division Long-Term Evolution), or 24 - 300 gigahertz used by 5G mobile communication technologies (such as: New Radio Frequency Technology), or depending on the wireless access technology used.

[0043] The controller 20 can be a general-purpose processor, a microprocessor (Micro-Control Unit, MCU), an application processor (Application Processor, AP), a digital signal processor (Digital Signal Processor, DSP), a graphics processing unit (Graphics Processing Unit, GPU), a holographic processing unit (Holographic Processing Unit, HPU), or a neural processing unit (Neural Processing Unit, NPU), or any combination of the above. Specifically, the controller 20 can include various logic circuits to provide functions of data processing and operation, control the wireless transceiver 10 to perform wireless communication with the mobile communication network 120, store and read data from the storage device 30 (such as: load and execute the program code of the 5G communication protocol), transmit video frame data to the display device 40, and receive or output signals through the input / output device 50. In particular, the controller 20 also integrates the operations of the wireless transceiver 10, the storage device 30, the display device 40, and the input / output device 50 to execute the enhanced signaling method of the always-on PDU session described in this application.

[0044] In another embodiment, the controller 20 can be integrated into the baseband processing device 11 as a baseband processor.

[0045] Those skilled in the art will understand that the logic circuit in the controller 20 generally includes multiple transistors for controlling the operation of the logic circuit to provide the required functions and operations. Further, the specific structure of the transistors and the connection relationships between them are usually determined by a compiler. For example, a Register Transfer Language (RTL) compiler can be operated by a processor to compile a script file similar to an assembly language code into a form suitable for designing or manufacturing the logic circuit. More specifically, the controller 20 can be divided into three parts: a "control unit", an "arithmetic logic unit", and a "register", but the present disclosure is not limited thereto. The control unit controls the functions to be executed according to the instructions of the program. The arithmetic logic unit is responsible for performing various operations. The register is implemented in a single hardware manner to store the data of the operation and the instructions to be continuously executed, or is implemented in two independent hardware manners to separately store the data of the operation and the instructions to be continuously executed.

[0046] The storage device 30 is a non-transitory computer-readable storage medium, including: memory (such as flash memory, non-volatile random access memory (NVRAM)), or magnetic storage devices (such as hard disks, magnetic tapes), or optical discs, or any combination of the above media, which is mainly used to store: computer-readable and executable instructions or program codes, including: applications, operating systems, and / or communication protocols (such as 5G communication protocols). For example, the method described in this application can be implemented as a part of the program code of a communication protocol (such as non-access stratum protocol code). In addition to the non-access stratum, the 5G communication protocol can also include: a Physical (PHY) layer, a Medium Access Control (MAC) layer, a Radio Link Control (RLC) layer, a Radio Resource Control (RRC) layer, a Packet Data Convergence Protocol (PDCP) layer, and a Service Data Adaptation Protocol (SDAP) layer.

[0047] The display device 40 can be a Liquid Crystal Display (LCD), a Light-Emitting Diode (LED) display, an Electronic Paper Display (EPD), etc., for providing a visual display function.

[0048] In another embodiment, the display device 40 may further include one or more touch detectors disposed thereon or thereunder, for detecting the contact or proximity of a conductive object (such as a finger, a stylus), so as to provide a touch-based human-machine interface operation, making the display device 40 a display device with a touch detection function.

[0049] The input / output device 50 may include one or more buttons, a keyboard, a mouse, a touchpad, a video camera, a microphone, a speaker, and / or various sensors (such as a barometric / temperature sensor, a humidity sensor, a blood pressure / heart rate / body temperature sensor), etc., for interacting with the user as a human-machine interface.

[0050] It should be understood that Figure 2 The elements shown are only used to provide an illustrative example and are not intended to limit the protection scope of this application. For example, the user equipment 110 may include more other elements, such as a power supply, and / or a Global Positioning System (GPS) device, etc. The power supply can be a portable / replaceable rechargeable battery, responsible for providing power to other elements in the user equipment 110. The GPS device can provide the current location information of the user equipment 110 for mobile positioning services / applications. Or, the user equipment 110 may also include fewer elements. For example, the user equipment 110 may not include the display device 40 and / or the input / output device 50.

[0051] Figure 3 It is an architecture diagram of a core network functional entity according to an embodiment of this application.

[0052] For example, the core network functional entity can be a computer computing device that implements one or more core network functions (such as user plane management functions) in the core network 122. As Figure 3 shown, the core network functional entity may include a network communication device 60, a controller 70, a storage device 80, and an input / output device 90.

[0053] The network communication device 60 is used to provide wired network access to connect to other network function entities in the access network 121 and the core network 122. In an example, the network communication device 60 may include an Ethernet adapter, an Asymmetric Digital Subscriber Line (ADSL) adapter, a fiber optic network adapter, or a communication device using other wired network technologies.

[0054] The controller 70 can be a general-purpose processor, a microprocessor, an application processor, a digital signal processor, a graphics processing unit, a holographic processing unit, or a neural processing unit, or any combination of the above. Specifically, the controller 70 may include various logic circuits for providing data processing and operation functions, controlling the network communication device 60 to communicate with other network function entities in the access network 121 and the core network 122, storing and reading data from the storage device 80 (such as loading and executing the non-access stratum program code of the 5G communication protocol), and receiving or outputting signals through the input / output device 90. In particular, the controller 70 also integrates the operations of the network communication device 60, the storage device 80, and the input / output device 90 to execute the enhanced signaling method of the always-on PDU session described in this application.

[0055] Those skilled in the art will understand that the logic circuits in the controller 70 usually include multiple transistors to control the operation of the logic circuits to provide the required functions and operations. Further, the specific structure of the transistors and the connection relationship between them are usually determined by a compiler. For example, a register transfer language compiler can be operated by a processor to compile a script file similar to an assembly language code into a form suitable for designing or manufacturing the logic circuits. More specifically, the controller 70 can be divided into three parts, namely, a "control unit", an "arithmetic logic unit", and a "register", but the present disclosure is not limited thereto. The control unit controls the functions to be executed according to the instructions of the program. The arithmetic logic unit is responsible for performing various operations. The register stores the data of the operation and the instructions to be continuously executed in a single hardware manner, or stores the data of the operation and the instructions to be continuously executed in two independent hardware manners respectively.

[0056] The storage device 80 is a non-transitory computer-readable storage medium, including: memory (such as flash memory, non-volatile random access memory), or magnetic storage devices (such as hard disks, magnetic tapes), or optical discs, or any combination of the above media, which is mainly used to store: computer-readable and executable instructions or program codes, including: application, operating system, and / or program codes of communication protocols (such as the non-access stratum of the 5G communication protocol).

[0057] The input / output device 90 may include one or more buttons, a keyboard, a mouse, a touchpad, a video camera, a microphone, and / or a speaker, etc., for interacting with the core network manager as a human-machine interface.

[0058] It should be understood that Figure 3 The elements shown are only used to provide an illustrative example and are not intended to limit the protection scope of this application. For example, the core network functional entity may include more other elements, such as a display device for providing a visual display function. Or, the core network functional entity may also include fewer elements. For example, the core network functional entity may not include the input / output device 90.

[0059] Figure 4 It is a message sequence chart (MSC) of the always-on protocol data unit session according to an embodiment of this application.

[0060] In step 410, the user equipment transmits an always-on protocol data unit session establishment request (PDU SESSION ESTABLISHMENT REQUEST) message or an always-on protocol data unit session modification request (PDU SESSION MODIFICATION REQUEST) message to the access and mobility function. Specifically, the always-on protocol data unit session establishment request message or the always-on protocol data unit session modification request message includes an always-on protocol data unit session request (APSR) information element (IE), and the always-on protocol data unit session request information element includes: an always-on protocol data unit session request and a lifetime indicator, where the always-on protocol data unit session request indicates a request to establish an always-on PDU session, and the lifetime indicator indicates a request to set the lifetime of the always-on PDU session.

[0061] For example, the always-on protocol data unit session request information element may be a data structure composed of eight bits, where the first bit is the always-on protocol data unit session request, the fifth to eighth bits are the identifier (IEI) of the information element, and the remaining bits are reserved bits, and the newly added lifetime indicator in this case can utilize any reserved bit (such as: the second bit).

[0062] In an example, the specific content of the always-on protocol data unit session request information element described in this application is shown in Table 1 below, but is not limited thereto.

[0063]

[0064] Table 1.

[0065] In an example, the set values and representative meanings of the always-on protocol data unit session request and the lifecycle metrics are shown in Table 2 below, but are not limited thereto.

[0066]

[0067]

[0068] Table 2.

[0069] In step 420, the access and mobility function and the session management function perform signaling exchange to select an appropriate session management function and user plane management function to handle the establishment or modification operation of this always-on protocol data unit session.

[0070] In step 430, the session management function and the user plane management function perform signaling exchange to establish an always-on PDU session.

[0071] In step 440, the session management function determines, based on its own resources, to allow the user equipment to establish an always-on PDU session and set the lifecycle, and thus transmits an always-on protocol data unit session establishment accept (PDU SESSION ESTABLISHMENT ACCEPT) message, or an always-on protocol data unit session modification instruction (PDU SESSION MODIFICATION COMMAND) message to the user equipment. Specifically, the always-on protocol data unit session establishment accept message, or the always-on protocol data unit session modification instruction message includes an always-on PDU session indication (APSI) information element, and the always-on PDU session indication information element includes: an always-on PDU session indication, and a lifecycle metric, where the always-on PDU session indication indicates permission to establish an always-on PDU session, and the lifecycle metric indicates that the 5G mobile communication network agrees to set the lifecycle of the always-on PDU session.

[0072] For example, the always-on PDU session indication information element may be a data structure composed of eight bits, where the first bit is the always-on PDU session indication, the fifth to eighth bits are the identifiers of this information element, and the remaining bits are reserved bits, and the newly added lifecycle metric in this case can utilize any reserved bit (such as: the second bit).

[0073] In an example, the specific content of the always-on PDU session metric information element described in this application is shown in Table 3 below, but is not limited thereto.

[0074]

[0075] Table 3.

[0076] In an example, the set values and representative meanings of the always-on PDU session metrics and lifecycle metrics are shown in Table 4 below, but are not limited thereto.

[0077]

[0078] Table 4.

[0079] In step 450, the access network decides to trigger a handover procedure to switch the user equipment to a 4G mobile communication network. Specifically, the user equipment may transmit a measurement report to the access network, and the access network then decides whether to trigger the handover procedure based on the content of the measurement report.

[0080] In step 460, the user equipment and the access and mobility function perform signaling exchange to handle the operations related to the user equipment leaving the 5G mobile communication network. Specifically, necessary signaling exchange is required among multiple functional entities on the network side to handle the handover operation. After that, the network side transmits a handover command message to the user equipment, and the user equipment leaves the 5G mobile communication network (e.g., switches to a 4G mobile communication network) according to the handover command message and returns a handover completion message. The network side can confirm that the user equipment has left the 5G mobile communication network after receiving the handover completion message.

[0081] In step 470, the session management function starts a timer (labeled as TLifetime in Figure 4 to count a duration representing the lifecycle of the always-on PDU session. In an example, this duration can be determined by the network side (e.g., the session management function) itself.

[0082] In step 480, the session management function determines that the user equipment has not reconnected to the 5G mobile communication network before the timer expires, so it performs signaling exchange with the user plane management function to release the always-on PDU session.

[0083] Figures 5A - 5B It is a signaling message sequence diagram of the always-on PDU session according to another embodiment of this application.

[0084] In step 510, the user equipment transmits an always-on protocol data unit session establishment request message, or an always-on protocol data unit session modification request message to the access and mobility function. Specifically, the always-on protocol data unit session establishment request message, or the always-on protocol data unit session modification request message includes an always-on protocol data unit session request information element, and the always-on protocol data unit session request information element includes: an always-on protocol data unit session request, and a lifecycle metric, where the always-on protocol data unit session request indicates a request to establish an always-on PDU session, and the lifecycle metric indicates a request to set the lifecycle of the always-on PDU session.

[0085] Regarding the data structure and setting of the always-on protocol data unit session request information element, reference can be made to Figure 4 the embodiments and Tables 1-2 thereof and will not be elaborated here.

[0086] In step 520, the access and mobility function and the session management function perform signaling exchange to select an appropriate session management function and user plane management function to handle the establishment or modification of this always-on protocol data unit session.

[0087] In step 530, the session management function determines based on its own resources that it is currently not allowed to establish an Always-on PDU session and set the lifecycle.

[0088] In step 540, the session management function transmits an always-on protocol data unit session establishment acceptance message, or an always-on protocol data unit session modification instruction message to the user equipment. Specifically, the always-on protocol data unit session establishment acceptance message, or the always-on protocol data unit session modification instruction message includes an always-on protocol data unit session metric information element, and the always-on protocol data unit session metric information element includes: an always-on protocol data unit session metric, a lifecycle metric, and a duration metric (labeled as BreathingSpace in Figure 5), where the always-on protocol data unit session metric indicates that it is not allowed to establish an always-on PDU session, the lifecycle metric indicates that the 5G mobile communication network does not agree to set the lifecycle of the always-on PDU session, and the duration metric indicates the time that the user equipment must wait before re-transmitting the always-on protocol data unit session establishment request message, or the always-on protocol data unit session modification request message.

[0089] For example, the always-on PDU session metric information element may be a data structure composed of eight bits, where the first bit is the always-on PDU session metric, the fifth to eighth bits are the identifiers of this information element, and the remaining bits are reserved bits. The newly added lifecycle metric in this case can utilize any one of the reserved bits (e.g., the second bit), and additionally, the newly added duration metric in this case can utilize any one or more of the reserved bits (e.g., the third to fourth bits).

[0090] In an example, the specific content of the always-on PDU session metric information element described in this application is as shown in Table 5 below, but not limited thereto.

[0091]

[0092] Table 5.

[0093] The set values and representative meanings of the always-on PDU session metric and the lifecycle metric are as shown in Table 4 above. In an example, the set values and representative meanings of the duration metric are as shown in Table 6 below, but not limited thereto.

[0094]

[0095] Table 6.

[0096] In step 550, the user equipment starts a timer (labeled as T Figure 5A ) according to the duration metric, and is not allowed to re-request the establishment of an always-on PDU session before the expiration of this timer. BreathingSpace )

[0097] In step 560, after the expiration of this timer, re-transmit an always-on PDU session establishment request message or an always-on PDU session modification request message to the access and mobility function. Specifically, the content of the re-transmitted always-on PDU session establishment request message or always-on PDU session modification request message is the same as the always-on PDU session establishment request message or always-on PDU session modification request message described in step 510.

[0098] In step 570, the access and mobility function and the session management function perform signaling exchange to select appropriate session management functions and user plane management functions to handle the establishment or modification operation of this always-on PDU session.

[0099] In step 580, the session management function and the user plane management function perform signaling exchange to establish an always-on PDU session.

[0100] In step 590, the session management function determines, based on its own resources, to allow the user equipment to establish an always-on PDU session and sets a lifecycle, and thus transmits an always-on protocol data unit session establishment acceptance message, or an always-on protocol data unit session modification instruction message, to the user equipment. Specifically, the always-on protocol data unit session establishment acceptance message, or the always-on protocol data unit session modification instruction message, includes an always-on protocol data unit session metric information element, and the always-on protocol data unit session metric information element includes: an always-on protocol data unit session metric, and a lifecycle metric, where the always-on protocol data unit session metric indicates permission to establish an always-on PDU session, and the lifecycle metric indicates that the 5G mobile communication network agrees to set the lifecycle of the always-on PDU session.

[0101] Regarding the data structure and setting of the always-on protocol data unit session metric information element, reference can be made to Figure 4 the embodiments and Tables 3 to 4 thereof, and details are not described herein again.

[0102] Figure 6 is a flowchart of an enhanced signaling method for an always-on protocol data unit session according to an embodiment of the present application.

[0103] In this embodiment, the enhanced signaling method for an always-on PDU session is applicable to a user equipment (e.g., user equipment 110), which includes at least one wireless transceiver (e.g., wireless transceiver 10) and a controller (e.g., controller 20).

[0104] In step 610, the user equipment transmits a non-access stratum request message to a mobile communication network, where the non-access stratum request message includes an always-on protocol data unit session request information element.

[0105] In an example, the non-access stratum request message may be an always-on protocol data unit session establishment request message. In another example, the non-access stratum request message may be an always-on protocol data unit session modification request message.

[0106] In step 620, the user equipment receives, from the mobile communication network, a non-access stratum response message including an always-on protocol data unit session metric information element, where the always-on protocol data unit session metric information element includes a duration metric.

[0107] In an example, the non-access stratum response message may be an always-on protocol data unit session establishment acceptance message. In another example, the non-access stratum response message may be an always-on protocol data unit session modification instruction message.

[0108] In step 630, the user equipment, in response to the above-mentioned always-on PDU session metric indicating that the establishment of an always-on PDU session is not allowed, starts a timer according to the above-mentioned duration metric and re-transmits the above-mentioned non-access stratum request message to the above-mentioned mobile communication network when the above-mentioned timer expires.

[0109] In an example, the user equipment may first determine whether there is pending data that needs to be transmitted through the always-on PDU session. If so, it starts the above-mentioned timer according to the above-mentioned duration metric to process the re-transmission operation.

[0110] In an example, the cooperation operation of the above-mentioned duration metric (i.e., BreathingSpace) and the above-mentioned timer (i.e., T BreathingSpace ) can refer to Figures 5A - 5B the embodiments thereof and the related descriptions.

[0111] Figure 7 is a flowchart of an enhanced signaling method for an always-on PDU session according to another embodiment of the present application.

[0112] In this embodiment, the enhanced signaling method for the always-on PDU session is applicable to a mobile communication network (e.g., mobile communication network 120), which at least includes an access network (e.g., access network 121) and a core network (e.g., core network 122).

[0113] In step 710, the mobile communication network receives a non-access stratum request message including an always-on PDU session request information element from a user equipment, wherein the always-on PDU session request information element includes a first lifecycle metric for requesting the mobile communication network to set a lifecycle for the always-on PDU session.

[0114] In an example, the non-access stratum request message may be an always-on PDU session establishment request message. In another example, the non-access stratum request message may be an always-on PDU session modification request message.

[0115] In step 720, the mobile communication network transmits a first non-access stratum response message including a first always-on PDU session metric information element in response to allowing the establishment of the always-on PDU session. In addition to indicating that the establishment of the always-on PDU session is allowed, the first always-on PDU session metric information element further includes a second lifecycle metric for indicating that the mobile communication network agrees to set the above-mentioned lifecycle.

[0116] In one example, the non-access stratum response message may be a PDU session establishment acceptance message for always-on. In another example, the non-access stratum response message may be a PDU session modification instruction message for always-on.

[0117] In step 730, in response to the user equipment leaving the mobile communication network, the mobile communication network starts a timer associated with the lifecycle.

[0118] In step 740, in response to the user equipment not reconnecting to the mobile communication network before the timer expires, the mobile communication network releases the always-on PDU session.

[0119] In another embodiment, in response to the user equipment reconnecting to the mobile communication network before the timer expires, the mobile communication network resets the timer and maintains the always-on PDU session.

[0120] In one example, the cooperation of the lifecycle metric (i.e., Lifetime) and the timer (i.e., TLifetime) may refer to Figure 4 the embodiments and related descriptions thereof.

[0121] Although the present application is disclosed above with various embodiments, they are only for reference by way of example and not intended to limit the scope of the present application. Any person skilled in the art can make some changes and refinements without departing from the spirit and scope of the present application. Therefore, the above embodiments are not intended to limit the scope of the present application, and the protection scope of the present application shall be defined by the scope of the appended patent application.

[0122]

Symbol Description

[0123] 100: Wireless communication environment

[0124] 110: User equipment

[0125] 120: Mobile communication network

[0126] 121: Access network

[0127] 122: Core network

[0128] 10: Wireless transceiver

[0129] 11: Baseband processing device

[0130] 12: Radio frequency device

[0131] 13: Antenna

[0132] 20: Controller

[0133] 30: Storage device

[0134] 40: Display device

[0135] 50: Input / output device

[0136] 60: Network communication device

[0137] 70: Controller

[0138] 80: Storage device

[0139] 90: Input / output device

[0140] 410 - 480, 510 - 590, 610 - 630, 710 - 740: Step numbers

Claims

1. An enhanced signaling method for a persistent protocol data unit session, applicable to a user equipment, the enhanced signaling method comprises: transmitting a non-access stratum request message to a mobile communication network, wherein the non-access stratum request message includes a persistent protocol data unit session request information element; receiving from the mobile communication network a non-access stratum response message including a persistent protocol data unit session metric information element, wherein the persistent protocol data unit session metric information element includes a duration metric; and in response to the persistent protocol data unit session metric indicating that establishment of a persistent protocol data unit session is not allowed, starting a timer according to the duration metric and re-transmitting the non-access stratum request message to the mobile communication network when the timer expires; wherein the persistent protocol data unit session request information element includes a first lifetime metric for requesting the mobile communication network to set a lifetime for the persistent protocol data unit session; and the persistent protocol data unit session metric information element includes a second lifetime metric for indicating whether the mobile communication network agrees to set the lifetime.

2. The enhanced signaling method according to claim 1, wherein the non-access stratum request message is a persistent protocol data unit session establishment request message, and the non-access stratum response message is a persistent protocol data unit session establishment acceptance message.

3. The enhanced signaling method according to claim 1, wherein the non-access stratum request message is a persistent protocol data unit session modification request message, and the non-access stratum response message is a persistent protocol data unit session modification instruction message.

4. The enhanced signaling method according to claim 1, further comprises: determining whether there is queued data in the user equipment that needs to be transmitted through the persistent protocol data unit session; wherein the starting of the timer is performed when there is queued data in the user equipment that needs to be transmitted through the persistent protocol data unit session.

5. A user equipment, comprises: a wireless transceiver for performing wireless transmission and reception with a mobile communication network; and a controller coupled to the wireless transceiver and configured to perform: transmitting, via the wireless transceiver, a non-access stratum request message to the mobile communication network, wherein the non-access stratum request message includes a persistent protocol data unit session request information element; receiving, via the wireless transceiver, from the mobile communication network a non-access stratum response message including a persistent protocol data unit session metric information element, wherein the persistent protocol data unit session metric information element includes a duration metric; and in response to the persistent protocol data unit session metric indicating that establishment of a persistent protocol data unit session is not allowed, starting a timer according to the duration metric and re-transmitting, via the wireless transceiver, the non-access stratum request message to the mobile communication network when the timer expires; Wherein the always - on protocol data unit session request information element includes a first lifecycle metric for requesting the mobile communication network to set a lifecycle for the always - on protocol data unit session; and the always - on protocol data unit session metric information element includes a second lifecycle metric for indicating whether the mobile communication network agrees to set the lifecycle.

6. The user equipment according to claim 5, wherein the non - access stratum request message is an always - on protocol data unit session establishment request message, and the non - access stratum response message is an always - on protocol data unit session establishment acceptance message.

7. The user equipment according to claim 5, wherein the non - access stratum request message is an always - on protocol data unit session modification request message, and the non - access stratum response message is an always - on protocol data unit session modification command message.

8. The user equipment according to claim 5, wherein the controller further determines whether there is queued data to be transmitted through the always - on protocol data unit session, and the timer is started when there is queued data to be transmitted through the always - on protocol data unit session.

9. An enhanced signaling method for an always - on protocol data unit session, applicable to a mobile communication network, the enhanced signaling method comprises: Receiving, from a user equipment, a non - access stratum request message including an always - on protocol data unit session request information element, wherein the always - on protocol data unit session request information element includes a first lifecycle metric for requesting the mobile communication network to set a lifecycle for an always - on protocol data unit session; Transmitting, in response to the mobile communication network allowing the establishment of the always - on protocol data unit session, a first non - access stratum response message including a first always - on protocol data unit session metric information element, wherein in addition to indicating the allowance of the establishment of the always - on protocol data unit session, the first always - on protocol data unit session metric information element includes a second lifecycle metric for indicating that the mobile communication network agrees to set the lifecycle; Starting a timer associated with the lifecycle in response to the user equipment leaving the mobile communication network; and Releasing the always - on protocol data unit session in response to the user equipment not reconnecting to the mobile communication network before the timer expires.

10. The enhanced signaling method according to claim 9, wherein the non - access stratum request message is an always - on protocol data unit session establishment request message, and the non - access stratum response message is an always - on protocol data unit session establishment acceptance message.

11. The enhanced signaling method according to claim 9, wherein the non - access stratum request message is an always - on protocol data unit session modification request message, and the non - access stratum response message is an always - on protocol data unit session modification command message.

12. The enhanced signaling method according to claim 9, further comprises: Resetting the timer and maintaining the always - on protocol data unit session in response to the user equipment reconnecting to the mobile communication network before the timer expires.

13. The enhanced signaling method according to claim 9, further comprises: transmitting a second non-access stratum response message including a second always-on protocol data unit session metric information element in response to the mobile communication network not allowing the establishment of the always-on protocol data unit session, wherein in addition to indicating that the establishment of the always-on protocol data unit session is not allowed, the second always-on protocol data unit session metric information element further includes a duration metric for indicating that the user equipment needs to wait for a period of time before retransmitting the non-access stratum request message.

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