Short message transmission method, device, and system

This application relates to the field of wireless communications technologies, and provides a short message transmission method. The method includes: receiving, by a communications device, uplink data and indication information used to indicate that the uplink data belongs to a short message service; determining identification information used to identify a short message function entity device that processes the short message service; and sending the uplink data to the short message function entity based on the indication information and the identification information; or includes: receiving, by a communications device from a terminal device, uplink data and a session identifier that is used to identify a session for processing the short message service; determining identification information associated with the session identifier; and sending the uplink data to the short message function entity based on the identification information.

TECHNICAL FIELD

This application relates to the field of wireless communications technologies, and in particular, to a short message transmission method, a device, and a system.

BACKGROUND

A short message service (SMS) is a widely applied telecommunications service. A short message is a non-real-time reliable data packet that can be transmitted in a public land mobile network (PLMN) through a signaling channel. A point-to-point data transmission service can be implemented by using the short message service. A point-to-point short message service includes a mobile terminated short message (MT SM) service and a mobile originated short message (MO SM) service.

In an existing 4G network, when a short message service needs to be performed, a short message may be transmitted to a short message center through an SGs interface between a mobility management entity (MME) and a mobile switching center (MSC). With the development of 5G networks, how to implement transmission of a non-access stratum (NAS) short message in a 5G network architecture needs to be urgently resolved.

SUMMARY

This application describes a short message transmission method, a device, and a system.

According to one aspect, an embodiment of this application provides a short message transmission method. The method includes: receiving, by a communications device (for example, an access and mobility management function AMF device), uplink data and indication information from a terminal device, where the indication information is used to indicate that the uplink data belongs to a short message service; determining, by the communications device, identification information, where the identification information is used to identify a short message function entity device (for example, a session management function SMF device) that processes the short message service; and sending, by the communications device, the uplink data to the short message function entity based on the indication information and the identification information. According to the solution provided in this embodiment, after uplink short message data arrives at the communications device, the communications device may send, based on the indication information and the obtained identification information, the uplink short message data to the SMF device that is capable of processing the short message service and that has completed short message service registration. In this way, uplink short message transmission is implemented in a next-generation mobile network architecture.

For the step of determining identification information, if the communications device has stored the identification information, the determining may be implemented directly by using the identification information. If the communications device does not have the identification information yet, the identification information may be obtained through an additional step, to implement the determining. The communications device may first receive the uplink data and the indication information from the terminal device, and then obtain the identification information; or may first obtain the identification information, and then receive the uplink data and the indication information from the terminal device. For example, the short message service registration may also be triggered by data (uplink data or downlink data). In other words, the short message service registration for the terminal device is not triggered until a network needs to forward short message data, so that user context storage load on a core network can be reduced.

In a possible design, the method further includes: sending, by the communications device, a first request message (for example, a registration trigger request message) to the short message function entity device; and receiving, by the communications device, a first response message (for example, a registration trigger response message) from the short message function entity device, where the first response message is used to indicate that the short message function entity device successfully registers the short message service. The first request message may trigger the short message function entity device to register the short message service with a subscriber data management SDM device, so that after a short message arrives subsequently, downlink short message data can be routed based on the identification information registered in the subscriber data management device.

In a possible design, the step of determining, by the communications device, the identification information includes: obtaining, by the communications device, an association between the identification information and the terminal device. In other words, the communications device may obtain the identification information at a granularity of a terminal device.

In a possible design, before the sending, by the communications device, the first request message to the short message function entity device, the method further includes: receiving, by the communications device, an attach request message from the terminal device, where the attach request message carries capability information, and the capability information is used to trigger the communications device to send the first request message; or after receiving the uplink data from the terminal device, determining, by the communications device, that the communications device does not have the identification information; or receiving, by the communications device, a notification message from a subscriber data management device, where the notification message carries a cause value: a mobile terminated short message service MT-SMS, and the cause value is used to trigger the communications device to send the first request message.

In the first manner described above, the short message function entity device may be triggered to register the short message service with the subscriber data management device in an attach procedure. In the second manner, the short message function entity device may be triggered only after the arrival of the uplink short message data, to register the short message service with the subscriber data management device in an attach procedure. In the third manner, the short message function entity device may be triggered only after the arrival of the downlink short message data, to register the short message service with the subscriber data management device in an attach procedure. The second and third manners can further reduce the user context storage load on the core network.

In a possible design, the first request message carries a mobile terminated short message service MT-SMS indication.

In a possible design, the first response message further carries downlink short message data. Returning the downlink short message data through the first response message can reduce signaling exchange between network elements of a core network.

In a possible design, the step of determining, by the communications device, the identification information includes: sending, by the communications device, a request message to a network function discovery device, where the request message carries a type of a requested network function: a short message function; and receiving, by the communications device, a response message from the network function discovery device, where the response message carries the identification information. For example, when the communications device does not have the identification information yet, the communications device may request the identification information from the network function discovery device.

In a possible design, the step of determining, by the communications device, the identification information includes: searching for, by the communications device, a context of the terminal device to obtain the identification information associated with the terminal device, where the context includes the association between the terminal device and the identification information. For example, after the communications device has stored the identification information, the communications device may directly determine the identification information based on the context of the identification information.

According to another aspect, this application further discloses a short message transmission method, including: receiving, by a short message function entity device (for example, a session management function SMF device), a first request message (for example, a registration trigger request message) from a communications device (for example, an access and mobility management function AMF device); sending, by the short message function entity device, a second request message (for example, a registration request message) to a subscriber data management SDM device based on the first request message, where the second request message includes identification information, and the identification information is used to identify the short message function entity device that processes the short message service; receiving, by the short message function entity device, a second response message (for example, a registration response message) from the SDM device, where the second response message carries subscription data of the short message service; and sending, by the short message function entity device, a first response message (for example, a registration trigger response message) to the communications device, where the first response message indicates that the short message function entity device successfully registers the short message service. According to the solution provided in this embodiment, the short message function entity device registers the short message service with the subscriber data management SDM device, so that after a short message arrives subsequently, downlink short message data can be routed based on the identification information registered in the subscriber data management device.

In a possible design, the method further includes: receiving, by the short message function entity device, downlink short message data from a short message center or the SDM device, where the first response message further includes the downlink short message data. Returning the downlink short message data through the first response message can reduce signaling exchange between network elements of a core network.

According to another aspect, this application further discloses a short message transmission method, including: receiving, by a subscriber data management SDM device, a route lookup request message from a short message center, to query identification information, where the identification information is used to identify a short message function entity device (for example, a session management function SMF device) that processes a short message service; if the SDM device does not have the identification information, sending, by the SDM device, a notification message to a communications device (for example, an access and mobility management function AMF device), where the notification message includes a cause value: a mobile terminated short message service MT-SMS, and the cause value is used to trigger the communications device to send a first request message (for example, a registration trigger request message) to the short message function entity device; receiving, by the SDM device, a second request message (for example, a registration request message) from the short message function entity device, where the second request message includes the identification information; and sending, by the SDM device, a second response message (for example, a registration response message) to the short message function entity device, where the second response message carries subscription data of the short message service. According to the solution provided in this embodiment, the short message function entity device may be triggered only after the arrival of downlink short message data, to register the short message service with the subscriber data management device in an attach procedure, so that short message transmission can be implemented in a next-generation mobile network architecture. In addition, user context storage load on a core network can be reduced.

In a possible design, the method further includes: sending, by the SDM device, the identification information to the SMC.

In a possible design, after the SDM device receives the route lookup request message from the SMC, the method further includes: receiving, by the SDM device, downlink short message data from the SMC, where the second response message carries the downlink short message data.

According to another aspect, this application further discloses a short message transmission method, including: sending, by a terminal device, uplink data and indication information to a communications device (for example, an access and mobility management function AMF device), where the indication information is used to indicate that the uplink data belongs to a short message service. According to the solution provided in this embodiment, after receiving the uplink data and the indication information, the communications device may learn, based on the indication information, that the uplink data belongs to the short message service; find, based on the indication information, a short message function entity device that processes the short message service; and then trigger the short message function entity device to register the short message service with a subscriber data management SDM device, thereby implementing short message transmission.

In a possible design, the method further includes: sending, by the terminal device, an attach request message to the communications device, where the attach request message carries capability information, and the capability information is used to trigger the communications device to send a first request message, thereby triggering registration of the short message service. In this manner, the short message function entity device may be triggered to register the short message service with the subscriber data management device in an attach procedure.

According to another aspect, this application further discloses a short message transmission method, including: receiving, by a communications device (for example, an access and mobility management function AMF device), uplink data and a session identifier from a terminal device, where the session identifier is used to identify a session for processing a short message service; determining, by the communications device, identification information associated with the session identifier, where the identification information is used to identify a short message function entity device (for example, a session management function SMF device) that processes the short message service; and sending, by the communications device, the uplink data to the short message function entity based on the identification information associated with the session identifier. According to the solution provided in this embodiment, after uplink short message data arrives at the communications device, the communications device sends, based on the session identifier, the uplink short message data to the SMF device that is capable of processing the short message service and that has completed short message service registration. In this way, uplink short message transmission is implemented in a next-generation mobile network architecture.

For the step of determining identification information associated with the session identifier, if the communications device has stored the identification information associated with the session identifier, the determining may be implemented directly by using the identification information. If the communications device does not have the identification information associated with the session identifier yet, the identification information associated with the session identifier may be obtained through an additional step, to implement the determining. The communications device may first receive the uplink data and the session identifier from the terminal device, and then obtain an association between the session identifier and the identification information; or may first obtain an association between the session identifier and the identification information, and then receive the uplink data and the session identifier from the terminal device. For example, registration of the short message service may be triggered by a service. To be specific, when uplink data or downlink data of the terminal arrives at a core network and needs to be forwarded, the core network determines an identifier of the short message function entity device, and triggers the short message function entity device to register the short message service, thereby registering the short message service as required, and reducing user context storage load on the core network.

In a possible design, the method further includes: sending, by the communications device, a first request message (for example, a registration trigger request message) to the short message function entity device, where the first request message carries a DNN of the short message service and the session identifier; and receiving, by the communications device, a first response message (for example, a registration trigger response message) from the short message function entity device, where the first response message is used to indicate that the short message function entity device successfully registers the short message service. The first request message may trigger the short message function entity device to register the short message service with a subscriber data management SDM device, so that after a short message arrives subsequently, downlink short message data can be routed based on the identification information registered in the subscriber data management device.

In a possible design, before the sending, by the communications device, the first request message to the short message function entity device, the method further includes:

receiving, by the communications device, an attach request message from the terminal device, where the attach request message carries the DNN and the session identifier; or

receiving, by the communications device, a session request message from a subscriber data management SDM device, where the session request message carries the DNN; and obtaining the session identifier in a session establishment process.

In the first manner described above, the short message function entity device may be triggered to register the short message service with the subscriber data management device in an attach procedure. In the second manner, the short message function entity device may be triggered only after the arrival of the downlink short message data, to register the short message service with the subscriber data management device in an attach procedure. The second manner can further reduce user context storage load on a core network.

In a possible design, the first request message carries a mobile terminated short message service MT-SMS indication.

In a possible design, the first response message further carries the downlink short message data. Returning the downlink short message data through the first response message can reduce signaling exchange between network elements of a core network.

In a possible design, if the terminal device is in an idle state, the method further includes: sending, by the communications device, a paging message to the terminal device, where the paging message carries a cause value: a mobile terminated short message service MT-SMS, and the paging message is used to trigger context setup of a session for the short message service.

In a possible design, the step of determining, by the communications device, the identification information associated with the session identifier includes: sending, by the communications device, a request message to a network function discovery device, where the request message carries the DNN and a type of a requested network function: a short message function; receiving, by the communications device, a response message from the network function discovery device, to obtain the identification information, where the response message carries the identification information; and associating, by the communications device, the identification information with the session identifier. For example, when the communications device does not have the identification information yet, the communications device may request the identification information from the network function discovery device.

In a possible design, the step of determining, by the communications device, the identification information associated with the session identifier includes: searching for, by the communications device, a context of the terminal device to obtain the identification information associated with the session identifier, where the context includes an association between the session identifier and the identification information. For example, after the communications device has stored the identification information associated with the session identifier, the communications device may directly determine the identification information based on the context of the identification information.

In a possible design, the communications device may send uplink short message data or downlink short message data through the session for the short message.

According to another aspect, this application further discloses a short message transmission method, including: receiving, by a short message function entity device (for example, a session management function SMF device), a first request message (for example, a registration trigger request message) from a communications device (for example, an access and mobility management function AMF device), where the first request message carries a DNN of a short message service and a session identifier, and the session identifier is used to indicate a session for the short message service; sending, by the short message function entity device, a second request message (for example, a registration request message) to a subscriber data management SDM device based on the first request message, where the second request message includes identification information, and the identification information is used to identify the short message function entity device that processes the short message service; receiving, by the short message function entity device, a second response message (for example, a registration response message) from the SDM device, where the second response message carries subscription data of the short message service; and sending, by the short message function entity device, a first response message (for example, a registration trigger response message) to the communications device, where the first response message indicates that the short message function entity device successfully registers the short message service. According to the solution provided in this embodiment, the short message function entity device registers the short message service with the subscriber data management SDM device, so that after a short message arrives subsequently, downlink short message data can be routed based on the identification information registered in the subscriber data management device.

In a possible design, the method further includes: receiving, by the short message function entity device, downlink short message data from a short message center or the SDM device, where the first response message further includes the downlink short message data. Returning the downlink short message data through the first response message can reduce signaling exchange between network elements of a core network.

In a possible design, the short message function entity device may transmit uplink short message data or a downlink short message data through the session for the short message.

According to another aspect, this application further discloses a short message transmission method, including: receiving, by a subscriber data management SDM device, a route lookup request message from a short message center, to query identification information, where the identification information is used to identify a short message function entity device (for example, a session management function SMF device) that processes a short message service; if the SDM device does not have the identification information, sending, by the SDM device, a session request message to a communications device (for example, an access and mobility management function AMF device), where the session request message carries a DNN of the short message service, and the session request message is used to trigger setup of a session for the short message service; receiving, by the SDM device, a second request message (for example, a registration request message) from the short message function entity device, where the second request message includes the identification information; and sending, by the SDM device, a second response message (for example, a registration response message) to the short message function entity device, where the second response message carries subscription data of the short message service. According to the solution provided in this embodiment, the short message function entity device may be triggered only after the arrival of downlink short message data, to register the short message service with the subscriber data management device in an attach procedure, so that short message transmission can be implemented in a next-generation mobile network architecture. In addition, user context storage load on a core network can be reduced.

In a possible design, the method further includes: sending, by the SDM device, the identification information to the SMC.

In a possible design, after the SDM device receives the route lookup request message from the SMC, the method further includes: receiving, by the SDM device, downlink short message data from the SMC, where the second response message carries the downlink short message data.

According to another aspect, this application further discloses a short message transmission method, including: sending, by a terminal device, uplink data and a session identifier to a communications device (for example, an access and mobility management function AMF device), where the session identifier is used to identify a session for processing the short message service. According to the solution provided in this embodiment, after receiving the uplink data and the session identifier, the communications device may determine, based on the session identifier, identification information associated with the session identifier; find a short message function entity device that processes the short message service; and then trigger the short message function entity device to register the short message service with a subscriber data management SDM device, thereby implementing short message transmission.

In a possible design, the method further includes: sending, by the terminal device, an attach request message to the communications device, where the attach request message carries a DNN of the short message service and the session identifier, thereby triggering registration of the short message service. In this manner, the short message function entity device may be triggered to register the short message service with the subscriber data management device in an attach procedure.

According to another aspect, an embodiment of this application provides a communications device (for example, an access and mobility management function AMF device), where the communications device has functions of implementing behaviors of the communications device in the foregoing methods. The functions may be implemented by hardware, or may be implemented by hardware executing corresponding software. The hardware or software includes one or more modules that correspond to the foregoing functions. In a possible design, a structure of the communications device includes a processor and a transceiver, where the processor is configured to support the communications device in performing a corresponding function in the foregoing methods, and the transceiver is configured to implement communication between the communications device and the foregoing terminal device/short message function entity device/subscriber data management device. The communications device may further include a memory, where the memory is configured to be coupled to the processor, and the memory stores a program instruction and data that are necessary for the communications device.

According to another aspect, an embodiment of this application provides a short message function entity device (for example, a session management function SMF device), where the communications device has functions of implementing behaviors of the short message function entity device in the foregoing methods. The functions may be implemented by hardware, or may be implemented by hardware executing corresponding software. The hardware or software includes one or more modules that correspond to the foregoing functions. In a possible design, a structure of the short message function entity device includes a processor and a transceiver, where the processor is configured to support the communications device in performing a corresponding function in the foregoing methods, and the transceiver is configured to implement communication between the short message function entity device and the foregoing communications device/subscriber data management device/short message center. The short message function entity device may further include a memory, where the memory is configured to be coupled to the processor, and the memory stores a program instruction and data that are necessary for the short message function entity device.

According to another aspect, an embodiment of this application provides a subscriber data management SDM device, where the subscriber data management device has functions of implementing behaviors of the subscriber data management device in the foregoing methods. The functions may be implemented by hardware, or may be implemented by hardware executing corresponding software. The hardware or software includes one or more modules that correspond to the foregoing functions. In a possible design, a structure of the subscriber data management device includes a processor and a transceiver, where the processor is configured to support the subscriber data management device in performing a corresponding function in the foregoing methods, and the transceiver is configured to implement communication between the subscriber data management device and the foregoing communications device/short message function entity device/short message center. The subscriber data management device may further include a memory, where the memory is configured to be coupled to the processor, and the memory stores a program instruction and data that are necessary for the subscriber data management device.

According to another aspect, an embodiment of this application provides a terminal device, where the terminal device has functions of implementing behaviors of the terminal device in the foregoing methods. The functions may be implemented by hardware, or may be implemented by hardware executing corresponding software. The hardware or software includes one or more modules that correspond to the foregoing functions. In a possible design, a structure of the terminal device includes a processor and a transceiver, where the processor is configured to support the terminal device in performing a corresponding function in the foregoing methods, and the transceiver is configured to implement communication between the terminal device and the foregoing communications device. The terminal device may further include a memory, where the memory is configured to be coupled to the processor, and the memory stores a program instruction and data that are necessary for the terminal device.

According to another aspect, an embodiment of this application provides a communications system, where the system includes the communications device and the short message function entity device that are described in the foregoing aspects. Optionally, the system may further include the subscriber data management SDM device in the foregoing aspects.

According to another aspect, an embodiment of this application provides a computer readable storage medium, where the computer readable storage medium stores an instruction, and when the instruction runs on a computer, the computer performs the methods according to the foregoing aspects.

According to another aspect, an embodiment of this application provides a computer program product including an instruction, where when the instruction runs on a computer, the computer performs the methods according to the foregoing aspects.

According to the technical solutions provided in the embodiments of this application, after the uplink short message data arrives at the communications device, the communications device may determine, based on the indication information or the session identifier, the identification information of the short message function entity device capable of processing the short message service, and send the uplink short message data to the short message function entity device that is capable of processing the short message service and that has completed short message service registration. In this way, the uplink short message transmission is implemented in the next-generation mobile network architecture.

DESCRIPTION OF EMBODIMENTS

The following clearly describes the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application.

Based on a communications system shown inFIG. 1, an embodiment of this application provides a solution, applicable to implementation of NAS short message transmission in a next-generation mobile network (for example, a 5G network) architecture. For example, in a 5G mobile network architecture, a control plane function and a forwarding plane function of a mobile gateway are decoupled, and the separated control plane function of the mobile gateway is combined with a conventional control network element MME, policy and charging rules function (PCRF), and the like of the 3rd Generation Partnership Project (3GPP) into a unified control plane device. A user plane device can implement user plane functions (SGW-U and PGW-U) of a serving gateway (SGW) and a packet data network gateway (PGW). Further, the unified control plane device may be decomposed into an access and mobility management function (AMF) device and a session management function (SMF) device. The AMF device may be responsible for procedures such as attach, mobility management, and tracking area update of a terminal device. The SMF device may be responsible for session management of a terminal device, selection of a user plane device, reselection of a user plane device, Internet Protocol (IP) address allocation, quality of service (QoS) control, bearer setup, bearer modification, and bearer release, and the like.

In addition, the embodiments of this application may be further applicable to other future-oriented communications technologies. The technical solutions provided in the embodiments of this application are applicable to any communications system using a new communications technology and including a device responsible for mobility management and a device responsible for session management. A system architecture and a service scenario described in the embodiments of this application are intended to describe the technical solutions in the embodiments of this application more clearly, but are not construed as a limitation to the technical solutions provided in the embodiments of this application. A person of ordinary skill in the art may know that, as the network architecture evolves and a new service scenario emerges, the technical solutions provided in the embodiments of this application are also applicable to a similar technical problem.

As shown inFIG. 1, an embodiment of this application provides a communications system100. For example, the communications system100includes a terminal device102, an access network device104, an AMF device106, an SMF device108, a subscriber data management (SDM) device110, a short message center (SMC)112, a user plane device114, and a data network (DN)116.

The terminal device102in this embodiment of this application may include various devices having a wireless communication function, such as a handheld device, an in-vehicle device, a wearable device, a computing device, or another processing device connected to a wireless modem. The terminal device may also be referred to as user equipment (UE), a mobile station (MS), or a terminal, and may further include a subscriber unit, a cellular phone, a smartphone, a wireless data card, a personal digital assistant (PDA) computer, a tablet computer, a wireless modem, a handheld device, a laptop computer, a cordless phone or a wireless local loop (WLL) station, a machine type communication (MTC) terminal, or the like.

The access network device104in this embodiment of this application is an apparatus that is deployed in a radio access network to provide a wireless communication function for the terminal device102. The access network device may include base stations in various forms, such as a macro base station, a micro base station (also referred to as a small cell), a relay station, and an access point. In systems using different radio access technologies, devices having a base station function may have different names. For example, in an LTE system, the device is referred to as an evolved NodeB (eNB or eNodeB); and in a 3rd generation (3G) system, the device is referred to as a NodeB.

The AMF device106in this embodiment of this application may be responsible for procedures such as attach, mobility management, and tracking area update of a terminal device.

The SMF device108in this embodiment of this application may be responsible for session management of a terminal device, selection of a user plane device (for example, the user plane device114), reselection of a user plane device, IP address allocation, QoS control, bearer setup, bearer modification, and bearer release.

The SDM device110in this embodiment of this application may be responsible for storage of user subscription data (for example, subscription data related to mobility management and subscription data related to session management).

The SMC112in this embodiment of this application may implement functions such as short message receiving, storage, and forwarding, and short message status reporting.

An embodiment of this application provides a short message transmission method: terminating NAS signaling for a 5G short message at the SMF device108. The SMF device108serves as a short message function entity device, processes short message data, and exchanges the short message data with the short message center112. The SMF device108is a control plane device having a session attribute. Therefore, in the short message transmission method of this application, a short message may be decoupled from a session, and transmitted by using only NAS signaling; or may be bound to a session, and transmitted through a session that is established by a core network for a short message service. The following describes the short message transmission method in this embodiment of this application with reference to embodiments ofFIG. 2toFIG. 8. In the methods shown inFIG. 2toFIG. 5, the short message and the session are decoupled. In the methods shown inFIG. 6toFIG. 8, the short message and the session are bound.

FIG. 2toFIG. 5are schematic flowcharts of a short message transmission method using only NAS signaling according to an embodiment of this application. In an example inFIG. 2, the terminal device102adds capability information to an attach request; and after receiving the capability information, the AMF device106determines the SMF device108capable of processing a short message service for the terminal device102, to trigger the SMF device108to register the short message service with the SDM device110. In other words, a short message service registration process may be implemented in an attach procedure of the terminal device102. In an example inFIG. 3, a short message service is not registered in an attach procedure of the terminal device102; and only after the terminal device102sends an uplink short message (MO SM), the AMF device106determines the SMF device108capable of processing a short message service for the terminal device102, to trigger the SMF device108to register the short message service with the SDM device110. Similarly, in examples inFIG. 4andFIG. 5, a short message service is not registered in an attach procedure of the terminal device102; and after a downlink short message (MT SM) arrives at the short message center112, the SDM device110triggers, based on an identifier of the AMF device106stored in the attach procedure, the AMF device106to determine the SMF device108capable of processing a short message service for the terminal device102, to trigger the SMF device108to register the short message service with the SDM device110.

FIG. 3toFIG. 5are all applicable to a scenario in which the terminal device102has no short message service for a relatively long period of time after being powered on and attached. In the example inFIG. 3, registration of a short message service may be triggered by an originated short message (namely, the uplink short message) of the terminal device102. In the examples inFIG. 4andFIG. 5, registration of a short message service may be triggered by a downlink short message. For example, in some actual scenarios, even if the terminal device102attaches to a network, a mobile originated short message service may be used infrequently. With the emergence of more applications, verification of a user identity by obtaining a short message verification code as a dynamic password to log in to an application or website account gradually becomes popular, and short message subscription (for example, for bank card balance notifications) is also quite common in daily life. In this behavior pattern, the terminal device102does not actively initiate transmission of a short message service, but receives some short message notification information (for example, service short messages about a weather forecast, an insufficient balance, and the like) from a website or an operator. In this scenario, a registration procedure of a short message service may be triggered by a downlink short message. Optionally,FIG. 3may be used in combination withFIG. 4orFIG. 5, depending on an occurrence sequence of the uplink short message and the downlink short message.

For example, in the example inFIG. 2, the short message transmission method includes the following steps.

In step202, the terminal device102sends an attach request message to the AMF device106via the access network device104. For example, the attach request message carries capability information. The capability information is used to trigger the AMF device106to send a registration trigger request message to an SMF device, to trigger a registration procedure of a short message service. In addition, the attach request message may further carry an international mobile subscriber identity (IMSI) used to identify the terminal device102.

In step204, the AMF device106obtains SMF identification information of an SMF device (for example, the SMF device108) capable of processing the short message service.

For example, the AMF device106sends a request message to a network function discovery device. The request message carries a type of a requested network function: a short message function.

After receiving the request message, the network function discovery device selects the SMF device (for example, the SMF device108) capable of processing the short message service, and returns a response message carrying the SMF identification information to the AMF device. The SMF identification information is used to identify the SMF device108that processes the short message service. For example, the SMF identification information includes an identifier ID or address of the SMF device that processes the short message service.

For example, the network function discovery device may be a domain name server (DNS) or a network function repository function (NRF).

Optionally, the SMF address may be used to route only uplink short message data, or route both uplink short message data and downlink short message data.

Optionally, before step204, the AMF device106may obtain subscription information of the terminal device102from the SDM device110through step203, to authenticate the terminal device102. The AMF device106obtains the SMF identification information for the terminal device102only after the terminal device102is authenticated.

In step206, the AMF device106sends the registration trigger request message to the SMF device108. For example, the registration trigger request message may carry the IMSI and an identifier of the AMF device106. Optionally, the registration trigger request message may further carry the foregoing capability information.

In step208, the SMF device108sends a registration request message to the SDM device110, to register the short message service with the SDM device110, where the registration request message carries the SMF identification information used to route downlink short message data. For example, the registration request message may carry the SMF identification information received in step206: the ID or address of the SMF device. Optionally, the SMF device108may further allocate a dedicated SMF address for routing a downlink short message, and send the dedicated SMF address as the SMF identification information to the SDM device110. In addition, the registration request message may further carry the IMSI and a flag bit (SMS in SMF feature flag) for the SMF to process the short message service.

In step210, the SMF device108completes registration of the short message service with the SDM device110. For example, the SDM device110may store the SMF identification information in the registration request message to route the downlink short message data, thereby implementing the registration of the short message service by the SMF device108. In addition, the SDM device110may further store the foregoing flag bit SMS in SMF feature flag.

In step212, the SDM device110sends a registration response message to the SMF device108, to notify the SMF device108that the SMF device108successfully registers the short message service. For example, the registration response message may carry short message service subscription information of the terminal device102. In addition, the registration response message may further carry the foregoing IMSI and flag bit SMS in SMF feature flag.

In step214, the SMF device108sends a registration trigger response message to the AMF device106, where the registration trigger response message is used to indicate that the SMF device108successfully registers the short message service. For example, the registration trigger response message may carry the IMSI, the SMF identification information, and the foregoing capability information.

In step216, the AMF device106obtains an association between the SMF identification information and the terminal device102. Optionally, the AMF device106may store the obtained association between the SMF identification information and the terminal device102in a context of the terminal device102.

It should be noted that step216may be performed immediately after the SMF identification information is obtained in step204; or may be performed after the registration trigger response message in step214is received and it is learned that the SMF device108has successfully registered the short message service with the SDM device110; or may be performed at any moment between step204and step214.

In step218, the AMF device106sends an attach accept message to the terminal device102via the access network device104, and completes an attach procedure, where the attach accept message may carry a temporary identifier ID allocated to the terminal device102.

In step220, the terminal device102encapsulates uplink short message data in an uplink NAS message, and sends the uplink NAS message to the AMF device106via the access network device104, where the uplink NAS message includes uplink data and indication information, and the indication information is used to indicate that the uplink data belongs to a short message service, that is, the uplink data is the uplink short message data. In addition, the uplink NAS message may further carry the temporary identifier of the terminal device102, current UE location information, a calling number, a called number, and the like.

In step222, the AMF device106determines, based on the foregoing indication information and SMF identification information, the SMF identification information of the SMF device (the SMF device108) capable of processing the short message service; and sends the uplink short message data to the SMF device108.

For example, the AMF device106learns, based on the indication information, that the uplink NAS message carries the uplink short message data; searches the context of the terminal device102for the SMF identification information determined in step216; determines, based on the SMF identification information, that an SMF device configured to process the uplink NAS message is the SMF device108; and then sends the uplink short message data to the SMF device108. Optionally, after receiving the uplink NAS message, the AMF device106first performs integrity check. The AMF device106sends the uplink short message data to the SMF device108only if the integrity check succeeds.

In step224, after receiving the uplink short message data, the SMF device108forwards the uplink short message data to the short message center112. For example, the SMF device108sends, based on the calling number, the uplink short message data to a short message center to which the terminal device102belongs. In addition, the SMF device108may further perform short message-related charging and lawful interception functions through an API for charging.

In step225, after receiving the uplink short message data from the SMF device108, the short message center112authenticates a calling user number segment, and returns a delivery report of declining or accepting.

According to the short message transmission method in this embodiment of this application, the SMF device108registers the short message service with the SDM device110in the attach procedure. In addition, the AMF device106obtains the SMF identification information of the SMF device capable of processing the short message service for the terminal device102. After the uplink NAS message carrying the uplink short message data arrives at the AMF device106, the AMF device106sends, based on the indication information in the uplink NAS message and the obtained SMF identification information, the uplink short message data to the SMF device that is capable of processing the short message service and that has completed short message service registration. In this way, uplink short message transmission is implemented in a next-generation mobile network architecture.

In addition, when a downlink short message arrives at the short message center112, downlink short message transmission may be implemented through steps226to230.

In step226, the short message center112requests, from the SDM device110, the SMF identification information (for example, the ID or address of the SMF device108) of the SMF device that is used to route the downlink short message. Because the SMF identification information of the SMF device108has been registered in the SDM device110, the SDM device110feeds back the SMF identification information of the SMF device108that may be configured to route the downlink short message.

In step228, the short message center112sends the downlink short message data to the SMF device108; and after receiving the downlink short message data, the SMF device108sends the downlink short message data to the AMF device106. In addition, the SMF device108may further perform short message-related charging and lawful interception functions through the API for charging.

In step230, the AMF device106encapsulates the downlink short message data in a downlink NAS message, and sends the downlink NAS message to the terminal device via the access network device104.

In addition, because the SMF device108may further perform the short message-related charging and lawful interception functions through the API for charging, no additional API for charging is needed, and interface resources of the SMF device can be saved.

As described above, the example inFIG. 3is applicable to the scenario in which the terminal device102has no short message service for a relatively long period of time after being powered on and attached. The terminal device102does not register a short message service during an attach procedure, and an originated short message of the terminal device102may trigger registration of the short message service. As shown inFIG. 3, the short message transmission method includes the following steps.

In step302, the terminal device102encapsulates uplink short message data in an uplink NAS message, and sends the uplink NAS message to the AMF device106via the access network device104, where the NAS message includes uplink data and indication information, and the indication information is used to indicate that the uplink data belongs to a short message service, that is, the uplink data is the uplink short message data. In addition, the uplink NAS message may further carry a temporary identifier of the terminal device102, current UE location information, a calling number, a called number, and the like.

In step304, after receiving the uplink data, the AMF device106determines that the AMF device106does not have SMF identification information of an SMF device that processes the short message service. For example, the AMF device106searches for a context of the terminal device102locally, where the SMF identification information does not exist in the context. After determining that the SMF identification information does not exist, the AMF device106obtains SMF identification information of an SMF device (for example, the SMF device108) capable of processing the short message service.

In step306, the AMF device106sends a registration trigger request message to the SMF device108.

In step308, the SMF device108sends a registration request message to the SDM device110, to register the short message service with the SDM device110.

In step310, the SMF device108completes registration of the short message service with the SDM device110.

In step312, the SDM device110sends a registration response message to the SMF device108, to notify the SMF device108that the SMF device108successfully registers the short message service.

In step314, the SMF device108sends a registration trigger response message to the AMF device106, where the registration trigger response message is used to indicate that the SMF device108successfully registers the short message service.

In step316, the AMF device106obtains an association between the SMF identification information and the terminal device102.

For steps304to316, refer to the descriptions of steps204to216inFIG. 2. Details are not described herein again.

In step318, the AMF device106determines, based on the foregoing indication information and SMF identification information, the SMF identification information of the SMF device (the SMF device108) capable of processing the short message service; and sends the uplink short message data to the SMF device108.

In step320, after receiving the uplink short message data, the SMF device108forwards the uplink short message data to the short message center112. In addition, the SMF device108may further perform short message-related charging and lawful interception functions through an API for charging.

In step321, after receiving the uplink short message data from the SMF device108, the short message center112authenticates a calling user number segment, and returns a delivery report of declining or accepting.

For steps318to321, refer to the descriptions of steps222to225inFIG. 2. Details are not described herein again.

According to the short message transmission method in this embodiment of this application, the SMF device108registers the short message service with the SDM device110after the terminal device102initiates an uplink short message. In addition, the AMF device106obtains the SMF identification information of the SMF device capable of processing the short message service for the terminal device102. The AMF device sends, based on the indication information in the uplink NAS message and the obtained SMF identification information, the uplink short message data to the SMF device that is capable of processing the short message service and that has completed short message service registration. In this way, uplink short message transmission is implemented in a next-generation mobile network architecture. In addition, a core network side triggers the registration of the short message service only after the arrival of the uplink short message, so that network resources used to store a user context on the core network side can be saved.

Similarly, when a downlink short message arrives at the short message center112, downlink short message transmission may be implemented through steps322to326.

In step322, the short message center112requests, from the SDM device110, the SMF identification information (for example, the ID or address of the SMF device108) of the SMF device that is used to route the downlink short message. Because the SMF identification information of the SMF device108has been registered in the SDM device110, the SDM device110feeds back the SMF identification information of the SMF device108that may be configured to route the downlink short message.

In step324, the short message center112sends the downlink short message data to the SMF device108; and after receiving the downlink short message data, the SMF device108sends the downlink short message data to the AMF device106. In addition, the SMF device108may further perform short message-related charging and lawful interception functions through the API for charging.

In step326, the AMF device106encapsulates the downlink short message data in a downlink NAS message, and sends the downlink NAS message to the terminal device via the access network device104.

As described above, the example inFIG. 4is applicable to the scenario in which the terminal device102has no short message service for a relatively long period of time after being powered on and attached. The terminal device102does not register a short message service during an attach procedure, and a downlink short message of the terminal device102may trigger registration of the short message service. As shown inFIG. 4, the short message transmission method includes the following steps.

In step401, an attach procedure of the terminal device102is performed. In the attach procedure, because the AMF device106needs to register location information of the terminal device102with the SDM device110, the SDM device110may obtain an identifier of the AMF device106, namely, an AMF ID.

In step402, after the arrival of the downlink short message, the short message center112sends a route request message of downlink short message data to the SDM device110, to query routing information of the downlink short message data.

In step404, the SDM device110determines that the SDM device110does not have SMF identification information of an SMF device that processes the short message service. For example, the SDM device110searches for a context of the terminal device102locally. Because the short message service has been registered with the SDM device110, the foregoing SMF identification information does not exist in the context.

In step406, after determining that the SMF identification information does not exist, the SDM device110sends a notification message to the AMF device106. For example, the SDM device110sends the notification message to the AMF device106based on the AMF ID obtained in the attach procedure. The notification message carries a cause value: a mobile terminated short message service MT-SMS, and the cause value is used to trigger the AMF device106to send a registration trigger request message to the SMF device.

In step408, the AMF device obtains the SMF identification information of the SMF device (for example, the SMF device108) capable of processing the short message service.

In step410, the AMF device106sends the registration trigger request message to the SMF device108.

In step412, the SMF device108sends a registration request message to the SDM device110, to register the short message service with the SDM device110.

In step414, the SMF device108completes registration of the short message service with the SDM device110.

In step416, the SDM device110sends a registration response message to the SMF device108, to notify the SMF device108that the SMF device108successfully registers the short message service.

For steps408to416, refer to the descriptions of steps204to212inFIG. 2. Details are not described herein again.

Optionally, the registration trigger request message in step410may further include a mobile terminated short message service MT-SMS indication. The indication is used to notify the SMF device108that the registration trigger request message is triggered by the downlink short message. Depending on whether the registration trigger request message includes the indication, subsequent steps may be implemented by using a different solution, namely, Solution A or Solution B.

In Solution A, the registration trigger request message in step410may include or may not include the mobile terminated short message service MT-SMS indication. The downlink short message data is sent to the terminal device102through steps418to426, as shown inFIG. 4.

In step418, after receiving the registration response message, the SMF device108directly sends a registration trigger response message to the AMF device106, where the registration trigger response message is used to indicate that the SMF device108successfully registers the short message service. For example, the registration trigger response message may carry the IMSI and the SMF identification information.

After receiving the registration trigger response message, the AMF device106determines, based on a status of the terminal device102, whether the terminal device102needs to be paged. Optionally, if the terminal device102is in an idle state, the AMF device106pages the terminal device102through step419, so that the terminal device102enters a connected (active) state.

In step420, the SDM device110sends the registered SMF identification information of the SMF device108to the short message center112.

It should be noted that step420may be performed after, or at the same time as, or before step418. Provided that the SDM device110has completed registration of the short message service through step414, the SDM device110may transfer the registered SMF identification information of the SMF device108to the short message center at any moment through step420.

In step422, after receiving the SMF identification information, the short message center112sends the downlink short message data to the SMF device108; and after receiving the downlink short message data, the SMF device108sends the downlink short message data to the AMF device106through step424. In addition, the SMF device108may further perform short message-related charging and lawful interception functions through an API for charging.

In step426, the AMF device106encapsulates the downlink short message data in a downlink NAS message, and sends the downlink NAS message to the terminal device via the access network device104.

In addition, in step421, the AMF device106obtains an association between the SMF identification information and the terminal device102.

For step421, refer to the description of step216inFIG. 2. Details are not described herein again. It should be noted that step421may be performed immediately after the SMF identification information is obtained in step408; or may be performed after the registration trigger response message in step418is received and it is learned that the SMF device108has successfully registered the short message service with the SDM device110; or may be performed at any moment between step408and step418.

In Solution B, the registration trigger request message in step410includes the mobile terminated short message service MT-SMS indication. The downlink short message data is sent to the terminal device102through steps428to434, as shown inFIG. 4.

In step428, the SDM device110sends the registered SMF identification information of the SMF device108to the short message center112.

In step430, after receiving the SMF identification information, the short message center112sends the downlink short message data to the SMF device108.

In step432, because the registration trigger request message received by the SMF device108includes the mobile terminated short message service MT-SMS indication, the SMF device108sends a registration trigger response message to the AMF device106only after receiving the downlink short message data from the short message center112, where the registration trigger response message is used to indicate that the SMF device108successfully registers the short message service, the registration trigger response message further carries the downlink short message data, and the registration trigger response message may further carry the IMSI and the SMF identification information. In addition, the SMF device108may further perform short message-related charging and lawful interception functions through the API for charging.

After receiving the registration trigger response message, the AMF device106determines, based on a status of the terminal device102, whether the terminal device102needs to be paged. Optionally, if the terminal device102is in an idle state, the AMF device106pages the terminal device102through step433, so that the terminal device102enters a connected state.

In step434, the AMF device106encapsulates the downlink short message data in a downlink NAS message, and sends the downlink NAS message to the terminal device via the access network device104.

In addition, in step436, the AMF device106obtains an association between the SMF identification information and the terminal device102.

For step436, refer to the description of step216inFIG. 2. Details are not described herein again. It should be noted that step436may be performed immediately after the SMF identification information is obtained in step408; or may be performed after the registration trigger response message in step432is received and it is learned that the SMF device108has successfully registered the short message service with the SDM device110; or may be performed at any moment between step408and step416or between step428and step432.

As described above, the example inFIG. 5is also applicable to the scenario in which the terminal device102has no short message service for a relatively long period of time after being powered on and attached. The terminal device102does not register a short message service during an attach procedure, and a downlink short message of the terminal device102may trigger registration of the short message service.FIG. 5differs fromFIG. 4in that, even if the short message center112has not found the routing information of the downlink short message data from the SDM device110, the short message center112sends the downlink short message data to the SDM device110first, to cache the downlink short message data in the SDM device110. After the SMF device108registers the short message service with the SDM device110, the SDM device110may send the cached downlink short message data to the SMF device108. As shown inFIG. 5, the short message transmission method includes the following steps.

In step501, an attach procedure of the terminal device102is performed. In the attach procedure, because the AMF device106needs to register location information of the terminal device102with the SDM device110, the SDM device110may obtain an identifier of the AMF device106, namely, an AMF ID.

In step502, after the arrival of the downlink short message, the short message center112sends a route request message of downlink short message data to the SDM device110, to query routing information of the downlink short message data.

In step504, the SDM device110determines that the SDM device110does not have SMF identification information of an SMF device that processes the short message service. For example, the SDM device110searches for a context of the terminal device102locally. Because the short message service has been registered with the SDM device110, the foregoing SMF identification information does not exist in the context.

In step506, even if the short message center112has not found the routing information of the downlink short message data from the SDM device110, the short message center112still sends the downlink short message data to the SDM device110first.

In step508, after receiving the downlink short message data, the SDM device110caches the downlink short message data locally.

In step510, the SDM device110sends a notification message to the AMF device106. For example, the SDM device110sends the notification message to the AMF device106based on the AMF ID obtained in the attach procedure. The notification message carries a cause value: a mobile terminated short message service MT-SMS, and the cause value is used to trigger the AMF device106to send a registration trigger request message to the SMF device.

It should be noted that step510may be performed after step508, or may be performed before step506or step508. This is not limited in this application.

In step512, the AMF device obtains SMF identification information of an SMF device (for example, the SMF device108) capable of processing the short message service.

In step514, the AMF device106sends the registration trigger request message to the SMF device108.

In step516, the SMF device108sends a registration request message to the SDM device110, to register the short message service with the SDM device110.

In step518, the SMF device108completes registration of the short message service with the SDM device110.

For steps512to518, refer to the descriptions of steps204to210inFIG. 2. Details are not described herein again.

In step520, the SDM device110sends a registration response message to the SMF device108, to notify the SMF device108that the SMF device108successfully registers the short message service. For example, the registration response message carries the cached downlink short message data and short message service subscription information of the terminal device102. In addition, the registration response message may further carry the foregoing IMSI and flag bit SMS in SMF feature flag.

In step522, the SMF device108sends a registration trigger response message to the AMF device106, where the registration trigger response message is used to indicate that the SMF device108successfully registers the short message service, the registration trigger response message carries the downlink short message data, and the registration trigger response message may further carry the IMSI and the SMF identification information. In addition, the SMF device108may further perform short message-related charging and lawful interception functions through an API for charging.

After receiving the registration trigger response message, the AMF device106determines, based on a status of the terminal device102, whether the terminal device102needs to be paged. Optionally, if the terminal device102is in an idle state, the AMF device106pages the terminal device102through step523, so that the terminal device102enters a connected state.

In step524, the AMF device106encapsulates the downlink short message data in a downlink NAS message, and sends the downlink NAS message to the terminal device via the access network device104.

In addition, in step526, the AMF device106obtains an association between the SMF identification information and the terminal device102.

For step526, refer to the description of step216inFIG. 2. Details are not described herein again. It should be noted that step526may be performed immediately after the SMF identification information is obtained in step512; or may be performed after the registration trigger response message in step526is received and it is learned that the SMF device108has successfully registered the short message service with the SDM device110; or may be performed at any moment between step512and step526.

For the examples inFIG. 4andFIG. 5, the downlink short message triggers the SMF device108to register the short message service with the SDM device110. After registration is completed, the SMF identification information of the SMF device108that is used to route the downlink short message data is stored in the SDM device. If a downlink short message arrives at the short message center112subsequently, the short message center112may query, from the SDM device110, routing information of the downlink short message, namely, the foregoing SMF identification information of the SMF device108. Therefore, the short message center112may send the downlink short message data to the SMF device108.

In addition, if an uplink short message arrives at the AMF device106subsequently, because the AMF device106has obtained the association between the terminal device102and the SMF identification information of the SMF device108that processes the short message service, the AMF device may directly determine, based on the SMF identification information, an SMF device that receives uplink short message data as the SMF device108that processes the short message service, and send the uplink short message data to the SMF device108.

The foregoing embodiments ofFIG. 2toFIG. 5describe a method for implementing short message transmission by using only NAS signaling. In the foregoing method, the AMF device106may serve as a NAS agent; and the SMF device108may be configured to terminate a short message service, and complete transmission of uplink and downlink short message data with the short message center112. The SMF device108may have a different name in the next-generation mobile network architecture, for example, a short message function entity device. This is not limited in this application.

For example, the short message transmission method includes the following steps:

receiving, by a communications device (for example, the AMF device106), uplink data and indication information from a terminal device (for example, the terminal device102), where the indication information is used to indicate that the uplink data belongs to a short message service (for example, step220inFIG. 2or step302inFIG. 3);

determining, by the communications device, identification information (for example, the foregoing SMF identification information), where the identification information is used to identify a short message function entity device (for example, the SMF device108) that processes the short message service; and

sending, by the communications device, the uplink data to the short message function entity based on the indication information and the identification information (for example, step222inFIG. 2or step318inFIG. 3).

It should be noted that, for the step of determining identification information, if the communications device has stored the identification information, the determining may be implemented directly by using the identification information. If the communications device does not have the identification information yet, the identification information may be obtained through an additional step, to implement the determining. The communications device may first receive the uplink data and the indication information from the terminal device, and then obtain the identification information (for example,FIG. 3); or may first obtain the identification information, and then receive the uplink data and the indication information from the terminal device (for example,FIG. 2,FIG. 4, orFIG. 5). This is not limited in this application.

According to the short message transmission method in this embodiment of this application, after the uplink short message data arrives at the communications device, the communications device sends, based on the indication information and the obtained identification information, the uplink short message data to the SMF device that is capable of processing the short message service and that has completed short message service registration. In this way, uplink short message transmission is implemented in a next-generation mobile network architecture. In addition, in the short message transmission method in this embodiment of this application, the short message service registration may also be triggered by data (uplink data or downlink data). In other words, the short message service registration for the terminal is not triggered until a network needs to forward short message data, so that user context storage load on a core network can be reduced.

Optionally, the method further includes: sending, by the communications device, a first request message (for example, refer to the registration trigger request message in step206inFIG. 2, step306inFIG. 3, step410inFIG. 4, or step514inFIG. 5) to the short message function entity device; and receiving, by the communications device, a first response message (for example, refer to the registration trigger response message in step214inFIG. 2, step314inFIG. 3, step418or432inFIG. 4, or step522inFIG. 5) from the short message function entity device, where the first response message is used to indicate that the short message function entity device successfully registers the short message service.

Optionally, the step of determining, by the communications device, the identification information (for example, the foregoing SMF identification information) includes: obtaining, by the communications device, an association between the identification information and the terminal device (for example, refer to step216inFIG. 2, step316inFIG. 3, step421or436inFIG. 4, or step526inFIG. 5).

Optionally, before the sending, by the communications device, the first request message to the short message function entity device, the method further includes:

receiving, by the communications device, an attach request message from the terminal device, where the attach request message carries capability information, and the capability information is used to trigger the communications device to send the first request message (for example, refer to step202inFIG. 2); or

after receiving the uplink data from the terminal device, determining, by the communications device, that the communications device does not have the identification information (for example, refer to step304inFIG. 3); or

receiving, by the communications device, a notification message from an SDM device (for example, the SDM device110), where the notification message carries a cause value: a mobile terminated short message service MT-SMS, and the cause value is used to trigger the communications device to send the first request message (for example, refer to step406inFIG. 4or step510inFIG. 5).

Optionally, the first request message carries a mobile terminated short message service MT-SMS indication (for example, refer to step410corresponding to Solution B inFIG. 4).

Optionally, the first response message further carries downlink short message data (for example, refer to step432inFIG. 4or step522inFIG. 5). Returning the downlink short message data through the first response message can reduce signaling exchange between network elements of a core network.

Optionally, the step of determining, by the communications device, the identification information includes: sending, by the communications device, a request message to a network function discovery device, where the request message carries a type of a requested network function: a short message function; and receiving, by the communications device, a response message from the network function discovery device, where the response message carries the identification information. For example, when the communications device does not have the identification information yet, the communications device may request the identification information from the network function discovery device.

Optionally, the step of determining, by the communications device, the identification information includes: searching for, by the communications device, a context of the terminal device to obtain the identification information associated with the terminal device, where the context includes the association between the terminal device and the identification information. For example, after the communications device has stored the identification information, the communications device may directly determine the identification information based on the context of the identification information.

In addition, this application further discloses a short message transmission method, including:

receiving, by a short message function entity device (for example, the SMF device108), a first request message (for example, refer to the registration trigger request message in step206inFIG. 2, step306inFIG. 3, step410inFIG. 4, or step514inFIG. 5) from a communications device (for example, the AMF device106);

sending, by the short message function entity device, a second request message (for example, refer to the registration request message in step208inFIG. 2, step308inFIG. 3, step412inFIG. 4, or step516inFIG. 5) to an SDM device (for example, the SDM device110) based on the first request message, where the second request message includes identification information (for example, the foregoing SMF identification information), and the identification information is used to identify the short message function entity device that processes the short message service;

receiving, by the short message function entity device, a second response message (for example, refer to the registration response message in step212inFIG. 2, step312inFIG. 3, step416inFIG. 4, or step520inFIG. 5) from the SDM device, where the second response message carries subscription data of the short message service; and

sending, by the short message function entity device, a first response message (for example, refer to the registration trigger response message in step214inFIG. 2, step314inFIG. 3, step418or432inFIG. 4, or step522inFIG. 5) to the communications device, where the first response message indicates that the short message function entity device successfully registers the short message service.

Optionally, the method further includes: receiving, by the short message function entity device, downlink short message data from a short message center (for example, the short message center112) or the SDM device, where the first response message further includes the downlink short message data (for example, refer to step432inFIG. 4or step522inFIG. 5).

In addition, this application further discloses a short message transmission method, including:

receiving, by an SDM device (for example, the SDM device110), a route lookup request message from a short message center (for example, the short message center112) to query identification information (for example, the foregoing SMF identification information), where the identification information is used to identify a short message function entity device (for example, the SMF device108in step402inFIG. 4or step502inFIG. 5) that processes a short message service;

if the SDM device does not have the identification information, sending, by the SDM device, a notification message to a communications device (for example, the AMF device106), where the notification message includes a cause value: a mobile terminated short message service MT-SMS, and the cause value is used to trigger the communications device to send a first request message (for example, the registration trigger request message in steps404and406inFIG. 4or steps504and510inFIG. 5) to the short message function entity device;

receiving, by the SDM device, a second request message (for example, the registration request message in step412inFIG. 4or step516inFIG. 5) from the short message function entity device, where the second request message includes the identification information; and

sending, by the SDM device, a second response message (for example, the registration response message in step416inFIG. 4or step520inFIG. 5) to the short message function entity device, where the second response message carries subscription data of the short message service.

Optionally, the method further includes: sending, by the SDM device, the identification information to the SMC (for example, step420or428inFIG. 4).

Optionally, after the SDM device receives the route lookup request message from the SMC, the method further includes: receiving, by the SDM device, downlink short message data from the SMC, where the second response message carries the downlink short message data (for example, steps506and520inFIG. 5).

In addition, this application further discloses a short message transmission method, including:

sending, by a terminal device (for example, the terminal device102), uplink data and indication information to a communications device (for example, the AMF device106), where the indication information is used to indicate that the uplink data belongs to a short message service (for example, step220inFIG. 2or step302inFIG. 3).

Optionally, the method further includes:

sending, by the terminal device, an attach request message to the communications device, where the attach request message carries capability information, and the capability information is used to trigger the communications device to send the first request message, thereby triggering registration of the short message service (for example, refer to step202inFIG. 2).

FIG. 6toFIG. 8are schematic flowcharts of a short message transmission method using a session according to an embodiment of this application. In an example inFIG. 6, the terminal device102adds, to an attach request, a data network name (DNN) of a short message service and a session identifier of a session for processing the short message service. After receiving the attach request, the AMF device106determines the SMF device108capable of processing the short message service for the terminal device102, to trigger the SMF device108to register the short message service with the SDM device110. In other words, a short message service registration process may be implemented in an attach procedure of the terminal device102. In addition, a session for the short message service may be established in the attach procedure. In examples inFIG. 7andFIG. 8, a short message service is not registered in an attach procedure of the terminal device102; and after a downlink short message (MT SM) arrives at the short message center112, the SDM device110triggers, based on an identifier of the AMF device106stored in the attach procedure, the AMF device106to determine the SMF device108capable of processing a short message service for the terminal device102, to trigger the SMF device108to register the short message service with the SDM device110.

FIG. 7andFIG. 8are both applicable to the scenario in which the terminal device102has no short message service for a relatively long period of time after being powered on and attached. For example, in some actual scenarios, even if the terminal device102attaches to a network, a mobile originated short message service may be used infrequently. With the emergence of more applications, verification of a user identity by obtaining a short message verification code as a dynamic password to log in to an application or website account gradually becomes popular, and short message subscription (for example, for bank card balance notifications) is also quite common in daily life. In this behavior pattern, the terminal device102does not actively initiate transmission of a short message service, but receives some short message notification information (for example, service short messages about a weather forecast, an insufficient balance, and the like) from a website or an operator. In this scenario, a registration procedure of a short message service may be triggered by a downlink short message.

For example, in the example inFIG. 6, the short message transmission method includes the following steps.

In step602, the terminal device102sends an attach request message to the AMF device106via the access network device104, where the attach request message further carries a packet data unit (PDU) session establishment request. For example, the attach request message carries a data network name (DNN) of the short message service: DNN (SMS) and a session identifier (session ID) allocated by the terminal device102to the short message service. The session identifier is used to identify a session for processing the short message service, to trigger a core network side to establish, for the terminal device102, a session for the short message service. In addition, the attach request message may further carry an IMSI used to identify the terminal device102.

For example, the attach request message may be a mobility management NAS (MM NAS) message or a session management NAS (SM NAS) message. The MM NAS message includes the IMSI and the DNN (SMS) of the short message service; and the SM NAS message (may be used as the PDU session establishment request) carries the session identifier.

In step604, the AMF device106obtains, based on the DNN, SMF identification information of an SMF device (for example, the SMF device108) capable of processing the short message service.

For example, the AMF device106learns, based on the DNN (SMS) in the MM NAS message, that the terminal device102processes the short message service, and sends a request message to a network function discovery device (for example, a DNS or NRF). The request message carries the DNN and a type of a requested network function: a short message function.

After receiving the request message, the network function discovery device selects, based on the DNN, the SMF device (for example, the SMF device108) capable of processing the short message service, and returns a response message carrying the SMF identification information to the AMF device. The SMF identification information is used to identify the SMF device108that processes the short message service. For example, the SMF identification information includes an identifier ID or address of the SMF device that processes the short message service. Optionally, the SMF address may be used to route only uplink short message data, or route both uplink short message data and downlink short message data.

Optionally, before step604, the AMF device106may obtain subscription information of the terminal device102from the SDM device110through step603, to authenticate the terminal device102. The AMF device106obtains the SMF identification information for the terminal device102only after the terminal device102is authenticated.

In step606, the AMF device106sends a registration trigger request message to the SMF device108, where the registration trigger request message may carry the DNN and the session identifier, and the registration trigger request message may further carry the IMSI and an identifier of the AMF device106. For example, the AMF device106adds the IMSI, the identifier of the AMF device106, and the DNN to the SM NAS message containing the session identifier, and forwards the new SM NAS message as the registration trigger request message to the SMF device108.

In step608, the SMF device108sends a registration request message to the SDM device110, to register the short message service with the SDM device110. For example, the registration request message carries the SMF identification information used to route downlink short message data. For example, the registration request message may carry the SMF identification information received in step606: the ID or address of the SMF device. Optionally, the SMF device108may allocate a dedicated SMF address for routing a downlink short message, and send the dedicated SMF address as the SMF identification information to the SDM device110. In addition, the registration request message may further carry the IMSI and a flag bit (SMS in SMF feature flag) for the SMF to process the short message service.

In step610, the SMF device108completes registration of the short message service with the SDM device110. For example, the SDM device110may store the SMF identification information in the registration request message to route the downlink short message data, thereby implementing the registration of the short message service by the SMF device108. In addition, the SDM device110may further store the foregoing flag bit SMS in SMF feature flag.

In step612, the SDM device110sends a registration response message to the SMF device108, to notify the SMF device108that the SMF device108successfully registers the short message service. For example, the registration response message may carry short message service subscription information of the terminal device102. In addition, the registration response message may further carry the foregoing IMSI and flag bit SMS in SMF feature flag.

In step614, the SMF device108sends a registration trigger response message to the AMF device106, where the registration trigger response message is used to indicate that the SMF device108successfully registers the short message service. For example, the registration trigger response message may carry the IMSI, the SMF identification information, and the foregoing session identifier.

In step616, the AMF device106obtains an association between the SMF identification information and the session identifier. For example, the AMF device106may store the obtained association between the identification information and the session identifier in a context of the terminal device102.

It should be noted that step616may be performed immediately after the SMF identification information is obtained in step604; or may be performed after the registration trigger response message in step614is received and it is learned that the SMF device108has successfully registered the short message service with the SDM device110; or may be performed at any moment between step604and step614.

In step618, the AMF device106sends an attach accept message to the terminal device102via the access network device104, and completes an attach procedure, where the attach accept message may carry a temporary identifier ID allocated to the terminal device102, and the attach accept message may further carry a PDU session establishment response.

In step620, the terminal device102encapsulates uplink short message data in an uplink NAS message, and sends the uplink NAS message to the AMF device106via the access network device104, where the NAS message includes uplink data and the session identifier, and the session identifier is used to identify the session for processing the short message service. In addition, the uplink NAS message may further carry the temporary identifier of the terminal device102, current UE location information, a calling number, a called number, and the like.

In step622, the AMF device106determines, based on the SMF identification information associated with the session identifier, the SMF identification information of the SMF device (the SMF device108) capable of processing the short message service; and sends the uplink short message data to the SMF device108.

For example, the AMF device106searches the context of the terminal device102for the SMF identification information associated with the session identifier in the uplink NAS message; determines that an SMF device configured to process the uplink NAS message is the SMF device108; and then sends the uplink short message data to the SMF device108. Optionally, after receiving the uplink NAS message, the AMF device106first performs integrity check. The AMF device106sends the uplink short message data to the SMF device108only if the integrity check succeeds.

In step624, after receiving the uplink short message data, the SMF device108forwards the uplink short message data to the short message center112. For example, the SMF device108sends, based on the calling number, the uplink short message data to a short message center to which the terminal device102belongs. In addition, the SMF device108may further perform short message-related charging and lawful interception functions through an API for charging.

Because the session for the short message service is established in the attach procedure, the uplink short message data may be transferred between the terminal device102and the AMF device106and between the AMF device106and the SMF device108through the session.

In step625, after receiving the uplink short message data from the SMF device108, the short message center112authenticates a calling user number segment, and returns a delivery report of declining or accepting.

According to the short message transmission method in this embodiment of this application, the SMF device108registers the short message service with the SDM device110in the attach procedure and establishes a PDU session dedicated for the short message service. In addition, the AMF device106associates the identification information of the SMF device capable of processing the short message service with the session identifier of the PDU session. After the uplink NAS message carrying the uplink short message data arrives at the AMF device, the AMF device determines, based on the session identifier in the uplink NAS message, the SMF identification information associated with the session identifier, to send the uplink short message data to the SMF device that is capable of processing the short message service and that has completed short message service registration. In this way, uplink short message transmission is implemented in a next-generation mobile network architecture.

In addition, the SMF device108having the session attribute can maintain sessions of all services. As one of the services, the short message service has a dedicated session, so that the SMF device108can maintain the session conveniently to implement short message transmission.

The AMF device addresses the SMF device based on a session identifier carried in an uplink short message packet, thereby keeping consistent with a routing mechanism of another session.

In addition, because the SMF device108may further perform the short message-related charging and lawful interception functions through the API for charging, no additional API for charging is needed, and interface resources of the SMF device can be saved.

In addition, when a downlink short message arrives at the short message center112, downlink short message transmission may be implemented through steps626to630.

In step626, the short message center112requests, from the SDM device110, the identification information (for example, the ID or address of the SMF device108) of the SMF device that is used to route the downlink short message. Because the identification information of the SMF device108has been registered in the SDM device110, the SDM device110feeds back the identification information of the SMF device108that may be configured to route the downlink short message.

In step628, the short message center112sends the downlink short message data to the SMF device108; and after receiving the downlink short message data, the SMF device108sends the downlink short message data to the AMF device106. In addition, the SMF device108may further perform short message-related charging and lawful interception functions through the API for charging.

In step630, the AMF device106encapsulates the downlink short message data in a downlink NAS message, and sends the downlink NAS message to the terminal device via the access network device104.

Because the session for the short message service is established in the attach procedure, the downlink short message data may be transferred between the terminal device102and the AMF device106and between the AMF device106and the SMF device108through the session.

As described above, the example inFIG. 7is applicable to the scenario in which the terminal device102has no short message service for a relatively long period of time after being powered on and attached. The terminal device102does not register a short message service during an attach procedure, and a downlink short message of the terminal device102may trigger registration of the short message service. As shown inFIG. 7, the short message transmission method includes the following steps.

In step701, an attach procedure of the terminal device102is performed. In the attach procedure, because the AMF device106needs to register location information of the terminal device102with the SDM device110, the SDM device110may obtain an identifier of the AMF device106, namely, an AMF ID.

In step702, after the arrival of the downlink short message, the short message center112sends a route request message of downlink short message data to the SDM device110, to query routing information of the downlink short message data.

In step704, the SDM device110determines that the SDM device110does not have SMF identification information of an SMF device that processes the short message service. For example, the SDM device110searches for a context of the terminal device102locally. Because the short message service has been registered with the SDM device110, the foregoing SMF identification information does not exist in the context.

In step706, after determining that the SMF identification information does not exist, the SDM device110sends a session request message to the AMF device106. For example, the SDM device110sends the session request message to the AMF device106based on the AMF ID obtained in the attach procedure. The session request message carries a DNN of the short message service: DNN (SMS). The DNN (SMS) is used to trigger establishment of a PDU session for the short message service. In addition, the session request message may further carry an IMSI used to identify the terminal device102.

After receiving the session request message, the AMF device106forwards the session request message to the terminal device102.

Optionally, after receiving the session request message, the AMF device106determines, based on a status of the terminal device102, whether the terminal device102needs to be paged. Optionally, if the terminal device102is in an idle state, the AMF device106sends a paging message to the terminal device102through step707, so that the terminal device102enters a connected (active) state. Optionally, the paging message carries a cause value: a mobile terminated short message service MT-SMS, and the paging message is used to trigger context setup of a session for the short message service.

In step708, after receiving the session request message, the terminal device102sends a PDU session establishment request to the AMF device106. For example, the PDU session establishment request carries a DNN of the short message service: DNN (SMS) and a session identifier allocated by the terminal device102to the short message service. The session identifier is used to identify a session for processing the short message service, to trigger a core network side to establish, for the terminal device102, a session for the short message service. In addition, the PDU session establishment request may further carry an IMSI used to identify the terminal device102.

For example, the PDU session establishment request may be an MM NAS message or an SM NAS message. The MM NAS message includes the IMSI and the DNN (SMS) of the short message service; and the SM NAS message carries the foregoing session identifier.

In step710, the AMF device106obtains SMF identification information of an SMF device (for example, the SMF device108) capable of processing the short message service.

In step712, the AMF device106sends a registration trigger request message to the SMF device108.

In step714, the SMF device108sends a registration request message to the SDM device110, to register the short message service with the SDM device110.

In step716, the SMF device108completes registration of the short message service with the SDM device110.

In step718, the SDM device110sends a registration response message to the SMF device108, to notify the SMF device108that the SMF device108successfully registers the short message service.

For steps710to718, refer to the descriptions of steps604to612inFIG. 6. Details are not described herein again.

Optionally, the registration trigger request message in step712may further include a mobile terminated short message service MT-SMS indication. The indication is used to notify the SMF device108that the registration trigger request message is triggered by the downlink short message. Depending on whether the registration trigger request message includes the indication, subsequent steps may be implemented by using a different solution, namely, Solution C or Solution D.

In Solution C, the registration trigger request message in step712may include or may not include the mobile terminated short message service MT-SMS indication. The downlink short message data is sent to the terminal device102through steps720to728, as shown inFIG. 7.

In step720, after receiving the registration response message, the SMF device108directly sends a registration trigger response message to the AMF device106, where the registration trigger response message is used to indicate that the SMF device108successfully registers the short message service. For example, the registration trigger response message may carry the IMSI, the SMF identification information, and the session identifier.

In step722, the SDM device110sends the registered SMF identification information of the SMF device108to the short message center112.

It should be noted that step722may be performed after, or at the same time as, or before step720. Provided that the SDM device110has completed registration of the short message service through step716, the SDM device110may transfer the registered SMF identification information of the SMF device108to the short message center at any moment through step722.

In step724, after receiving the SMF identification information, the short message center112sends the downlink short message data to the SMF device108; and after receiving the downlink short message data, the SMF device108sends the downlink short message data to the AMF device106through step726. In addition, the SMF device108may further perform short message-related charging and lawful interception functions through an API for charging.

In step728, the AMF device106encapsulates the downlink short message data in a downlink NAS message, and sends the downlink NAS message to the terminal device via the access network device104.

In addition, in step721, the AMF device106obtains an association between the SMF identification information and the session identifier.

For step721, refer to the description of step616inFIG. 6. Details are not described herein again. It should be noted that step721may be performed immediately after the SMF identification information is obtained in step710; or may be performed after the registration trigger response message in step720is received and it is learned that the SMF device108has successfully registered the short message service with the SDM device110; or may be performed at any moment between step710and step720.

In step723, the AMF device106returns a PDU session response to the terminal device102.

In Solution D, the registration trigger request message in step712includes the mobile terminated short message service MT-SMS indication. The downlink short message data is sent to the terminal device102through steps730to736, as shown inFIG. 4.

In step730, the SDM device110sends the registered SMF identification information of the SMF device108to the short message center112.

In step732, after receiving the SMF identification information, the short message center112sends the downlink short message data to the SMF device108.

In step734, because the registration trigger request message received by the SMF device108includes the mobile terminated short message service MT-SMS indication, the SMF device108sends a registration trigger response message to the AMF device106only after receiving the downlink short message data from the short message center112, where the registration trigger response message is used to indicate that the SMF device108successfully registers the short message service, the registration trigger response message further carries the downlink short message data, and the registration trigger response message may further carry the IMSI, the SMF identification information, and the session identifier. In addition, the SMF device108may further perform short message-related charging and lawful interception functions through the API for charging.

In step736, the AMF device106encapsulates the downlink short message data in a NAS message of the PDU session response, and sends the NAS message to the terminal device via the access network device104.

In addition, in step735, the AMF device106obtains an association between the SMF identification information and the session identifier.

For step735, refer to the description of step616inFIG. 6. Details are not described herein again. It should be noted that step735may be performed immediately after the SMF identification information is obtained in step710; or may be performed after the registration trigger response message in step734is received and it is learned that the SMF device108has successfully registered the short message service with the SDM device110; or may be performed after step736; or may be performed at any moment between step710and step718or between step730and step734.

As described above, the example inFIG. 8is also applicable to the scenario in which the terminal device102has no short message service for a relatively long period of time after being powered on and attached. The terminal device102does not register a short message service during an attach procedure, and a downlink short message of the terminal device102may trigger registration of the short message service.FIG. 8differs fromFIG. 7in that, even if the short message center112has not found the routing information of the downlink short message data from the SDM device110, the short message center112still sends the downlink short message data to the SDM device110first, to cache the downlink short message data in the SDM device110. After the SMF device108registers the short message service with the SDM device110, the SDM device110may send the cached downlink short message data to the SMF device108. As shown inFIG. 8, the short message transmission method includes the following steps.

In step801, an attach procedure of the terminal device102is performed. In the attach procedure, because the AMF device106needs to register location information of the terminal device102with the SDM device110, the SDM device110may obtain an identifier of the AMF device106, namely, an AMF ID.

In step802, after the arrival of the downlink short message, the short message center112sends a route request message of downlink short message data to the SDM device110, to query routing information of the downlink short message data.

In step804, the SDM device110determines that the SDM device110does not have SMF identification information of an SMF device that processes the short message service. For example, the SDM device110searches for a context of the terminal device102locally. Because the short message service has been registered with the SDM device110, the foregoing SMF identification information does not exist in the context.

In step806, even if the short message center112has not found the routing information of the downlink short message data from the SDM device110, the short message center112still sends the downlink short message data to the SDM device110first.

In step808, after receiving the downlink short message data, the SDM device110caches the downlink short message data locally.

In step810, the SDM device110sends a session request message to the AMF device106. After receiving the session request message, the AMF device106forwards the session request message to the terminal device102.

It should be noted that step810may be performed after step808, or may be performed before step806or step808. This is not limited in this application.

Optionally, after receiving the session request message, the AMF device106determines, based on a status of the terminal device102, whether the terminal device102needs to be paged. Optionally, if the terminal device102is in an idle state, the AMF device106sends a paging message to the terminal device102through step811, so that the terminal device102enters a connected state.

In step812, after receiving the session request message, the terminal device102sends a PDU session establishment request to the AMF device106.

In step814, the AMF device106obtains SMF identification information of an SMF device (for example, the SMF device108) capable of processing the short message service.

In step816, the AMF device106sends a registration trigger request message to the SMF device108.

In step818, the SMF device108sends a registration request message to the SDM device110, to register the short message service with the SDM device110.

In step820, the SMF device108completes registration of the short message service with the SDM device110.

For steps810to820, refer to descriptions of steps706to716inFIG. 7. Details are not described herein again.

In step822, the SDM device110sends a registration response message to the SMF device108, to notify the SMF device108that the SMF device108successfully registers the short message service. For example, the registration response message carries the cached downlink short message data and short message service subscription information of the terminal device102. In addition, the registration response message may further carry the foregoing IMSI and flag bit SMS in SMF feature flag.

In step824, the SMF device108sends a registration trigger response message to the AMF device106, where the registration trigger response message is used to indicate that the SMF device108successfully registers the short message service, the registration trigger response message carries the downlink short message data, and the registration trigger response message may further carry the IMSI, the SMF identification information, and the session identifier. In addition, the SMF device108may further perform short message-related charging and lawful interception functions through an API for charging.

In step828, the AMF device106encapsulates the downlink short message data in a NAS message of a PDU session response, and sends the NAS message to the terminal device via the access network device104.

In addition, in step826, the AMF device106obtains an association between the SMF identification information and the session identifier.

For step826, refer to the description of step616inFIG. 6. Details are not described herein again. It should be noted that step826may be performed immediately after the SMF identification information is obtained in step814; or may be performed after the registration trigger response message in step824is received and it is learned that the SMF device108has successfully registered the short message service with the SDM device110; or may be performed after step828; or may be performed at any moment between step814and step828.

For the examples inFIG. 7andFIG. 8, the downlink short message triggers the SMF device108to register the short message service with the SDM device110. After registration is completed, the SMF identification information of the SMF device108that is used to route the downlink short message data is stored in the SDM device. If a downlink short message arrives at the short message center112subsequently, the short message center112may query, from the SDM device110, routing information of the downlink short message, namely, the foregoing SMF identification information of the SMF device108. Therefore, the short message center112may send the downlink short message data to the SMF device108. Because the session for the short message service is established in the attach procedure, the downlink short message data may be transferred between the terminal device102and the AMF device106and between the AMF device106and the SMF device108through the session.

In addition, if an uplink short message arrives at the AMF device106subsequently, because the AMF device106has obtained the association between the session identifier and the SMF identification information of the SMF device108that processes the short message service, the AMF device may directly determine, based on the SMF identification information associated with the session identifier, an SMF device that receives uplink short message data as the SMF device108that processes the short message service, and send the uplink short message data to the SMF device108. Similarly, the uplink short message data may be transferred between the terminal device102and the AMF device106and between the AMF device106and the SMF device108through the session.

The foregoing embodiments ofFIG. 6toFIG. 8describe the method for implementing short message transmission by using a session. In the foregoing method, the AMF device106may serve as a NAS agent; and the SMF device108may be configured to terminate a short message service, and complete transmission of uplink and downlink short message data with the short message center112. The SMF device108may have a different name in the next-generation mobile network architecture, for example, a short message function entity device. This is not limited in this application.

For example, the short message transmission method includes the following steps:

receiving, by a communications device (for example, the AMF device106), uplink data and a session identifier from a terminal device (for example, the terminal device102), where the session identifier is used to identify a session for processing a short message service;

determining, by the communications device, identification information (for example, the foregoing SMF identification information) associated with the session identifier, where the identification information is used to identify a short message function entity device (for example, the SMF device108) that processes the short message service; and

sending, by the communications device, the uplink data to the short message function entity device based on the identification information associated with the session identifier.

It should be noted that, for the step of determining identification information associated with the session identifier, if the communications device has stored the identification information associated with the session identifier, the determining may be implemented directly by using the identification information. If the communications device does not have the identification information associated with the session identifier yet, the identification information associated with the session identifier may be obtained through an additional step, to implement the determining. The communications device may first receive the uplink data and the session identifier from the terminal device, and then obtain an association between the session identifier and the identification information; or may first obtain an association between the session identifier and the identification information, and then receive the uplink data and the session identifier from the terminal device. This is not limited in this application.

According to the short message transmission method in this embodiment of this application, after the uplink short message data arrives at the communications device, the communications device sends, based on the session identifier, the uplink short message data to the SMF device that is capable of processing the short message service and that has completed short message service registration. In this way, uplink short message transmission is implemented in a next-generation mobile network architecture. In addition, registration of the short message service may be triggered by a service. To be specific, when uplink data or downlink data of the terminal arrives at a core network and needs to be forwarded, the core network determines an identifier of the short message function entity device, and triggers the short message function entity device to register the short message service, thereby registering the short message service as required, and reducing context storage load on the core network.

Optionally, the method further includes: sending, by the communications device, a first request message (for example, refer to the registration trigger request message in step606inFIG. 6, step712inFIG. 7, or step816inFIG. 8) to the short message function entity device, where the first request message carries a DNN of the short message service and the session identifier; and receiving, by the communications device, a first response message (for example, refer to the registration trigger response message in step614inFIG. 6, steps720and734inFIG. 7, or step824inFIG. 8) from the short message function entity device, where the first response message is used to indicate that the short message function entity device successfully registers the short message service.

Optionally, before the sending, by the communications device, the first request message to the short message function entity device, the method further includes:

receiving, by the communications device, an attach request message from the terminal device, where the attach request message carries the DNN and the session identifier (for example, refer to step602inFIG. 6); or

receiving, by the communications device, a session request message from an SDM device (for example, the SDM device110), where the session request message carries the DNN; and obtaining the session identifier in a session establishment process (for example, refer to steps706to708inFIG. 7or steps810to812inFIG. 8).

Optionally, the first request message carries a mobile terminated short message service MT-SMS indication (for example, refer to step712corresponding to Solution D inFIG. 7).

Optionally, the first response message further carries downlink short message data (for example, step734inFIG. 7or step824inFIG. 8). Returning the downlink short message data through the first response message can reduce signaling exchange between network elements of a core network.

Optionally, if the terminal device is in an idle state, the method further includes: sending, by the communications device, a paging message to the terminal device, where the paging message carries a cause value: a mobile terminated short message service MT-SMS, and the paging message is used to trigger context setup of a session for the short message service (for example, refer to step707inFIG. 7or step811inFIG. 8).

Optionally, the step of determining, by the communications device, the identification information associated with the session identifier includes: sending, by the communications device, a request message to a network function discovery device, where the request message carries the DNN and a type of a requested network function: a short message function; receiving, by the communications device, a response message from the network function discovery device, to obtain the identification information, where the response message carries the identification information; and associating, by the communications device, the identification information with the session identifier. For example, when the communications device does not have the identification information yet, the communications device may request the identification information from the network function discovery device.

Optionally, the step of determining, by the communications device, the identification information associated with the session identifier includes: searching for, by the communications device, a context of the terminal device to obtain the identification information associated with the session identifier, where the context includes an association between the session identifier and the identification information. For example, after the communications device has stored the identification information associated with the session identifier, the communications device may directly determine the identification information based on the context of the identification information.

Optionally, the communications device may send uplink short message data or downlink short message data through the session for the short message.

In addition, this application further discloses a short message transmission method, including:

receiving, by a short message function entity device (for example, the SMF device108), a first request message (for example, refer to the registration trigger request message in step606inFIG. 6, step712inFIG. 7, or step816inFIG. 8) from a communications device (for example, the AMF device106), where the first request message carries a DNN of a short message service and a session identifier, and the session identifier is used to indicate a session for the short message service;

sending, by the short message function entity device, a second request message (for example, refer to the registration request message in step608inFIG. 6, step714inFIG. 7, or step818inFIG. 8) to an SDM device (for example, the SDM device110) based on the first request message, where the second request message includes identification information (for example, the foregoing SMF identification information), and the identification information is used to identify the short message function entity device that processes the short message service;

receiving, by the short message function entity device, a second response message (for example, refer to the registration response message in step612inFIG. 6, step718inFIG. 7, or step822inFIG. 8) from the SDM device, where the second response message carries subscription data of the short message service; and

sending, by the short message function entity device, a first response message (for example, refer to the registration trigger response message in step614inFIG. 6, steps720and734inFIG. 7, or step824inFIG. 8) to the communications device, where the first response message indicates that the short message function entity device successfully registers the short message service.

Optionally, the method further includes: receiving, by the short message function entity device, downlink short message data from a short message center (for example, the short message center112) or the SDM device, where the first response message further includes the downlink short message data (for example, refer to step734inFIG. 7or step824inFIG. 8).

Optionally, the short message function entity device may transmit uplink short message data or a downlink short message data through the session for the short message.

In addition, this application further discloses a short message transmission method, including:

receiving, by an SDM device (for example, the SDM device110), a route lookup request message from a short message center (for example, the short message center112) to query identification information (for example, the foregoing SMF identification information), where the identification information is used to identify a short message function entity device (for example, the SMF device108in step702inFIG. 7or step802inFIG. 8) that processes a short message service;

if the SDM device does not have the identification information, sending, by the SDM device, a session request message to a communications device (for example, the AMF device106), where the session request message carries a DNN of the short message service, and the session request message is used to trigger establishment of a session for the short message service (for example, steps704and706inFIG. 7or steps804and810inFIG. 8);

receiving, by the SDM device, a second request message (for example, the registration request message in step714inFIG. 7or step818inFIG. 8) from the short message function entity device, where the second request message includes the identification information; and

sending, by the SDM device, a second response message (for example, the registration response message in step718inFIG. 7or step822inFIG. 8) to the short message function entity device, where the second response message carries subscription data of the short message service.

Optionally, the method further includes: sending, by the SDM device, the identification information to the SMC (for example, step722or730inFIG. 7).

Optionally, after the SDM device receives the route lookup request message from the SMC, the method further includes: receiving, by the SDM device, downlink short message data from the SMC, where the second response message carries the downlink short message data (for example, steps806and822inFIG. 8).

In addition, this application further discloses a short message transmission method, including:

sending, by a terminal device (for example, the terminal device102), uplink data and a session identifier to a communications device (for example, the AMF device106), where the session identifier is used to identify a session for processing a short message service (for example, step620inFIG. 6).

Optionally, the method further includes:

sending, by the terminal device, an attach request message to the communications device, where the attach request message carries a DNN of the short message service and the session identifier, thereby triggering registration of the short message service (for example, refer to step602inFIG. 6).

In the foregoing embodiments provided in this application, the solutions such as the short message transmission method provided in the embodiments of this application are described from the perspectives of network elements and interaction between the network elements. It should be understood that, to implement the foregoing functions, each network element, for example, the communications device, the short message function entity device, the subscriber data management device, or the terminal device, includes a corresponding hardware structure and/or a software module for performing each function. A person skilled in the art should be easily aware that, in combination with the examples described in the embodiments disclosed in this specification, units and algorithm steps may be implemented by hardware or a combination of hardware and computer software. Whether a function is performed by hardware or hardware driven by computer software depends on particular applications and design constraints of the technical solutions. A person skilled in the art may use different methods to implement the described functions for each particular application, but it should not be considered that the implementation goes beyond the scope of this application.

For example, when the foregoing network elements implement corresponding functions by using software modules, the communications device may include a receiving module901, a determining module903, and a sending module905, as shown inFIG. 9A. For example, the communications device may be implemented by the AMF device106.

In an embodiment, the receiving module901is configured to receive uplink data and indication information from a terminal device, where the indication information is used to indicate that the uplink data belongs to a short message service; the determining module903is configured to determine identification information, where the identification information is used to identify a short message function entity device that processes the short message service; and the sending module905is configured to send the uplink data to the short message function entity based on the indication information and the identification information. For example, the receiving module901may be configured to perform any one of steps202,214,220, and228inFIG. 2, steps302,314, and324inFIG. 3, steps406,418,424, and432inFIG. 4, or steps510and522inFIG. 5; the determining module903may be configured to perform any one of steps203,204,216, and222inFIG. 2, steps304,316, and318inFIG. 3, steps408,419,421,433, and436inFIG. 4, or steps512,523, and526inFIG. 5; and the sending module905may be configured to perform any one of steps206,218,222, and230inFIG. 2, steps306,318, and326inFIG. 3, steps410,426, and434inFIG. 4, or steps514and524inFIG. 5.

In another embodiment, the receiving module901is configured to receive uplink data of a short message service and a session identifier from a terminal device, where the session identifier is used to identify a session for processing the short message service; the determining module903is configured to determine identification information associated with the session identifier, where the identification information is used to identify a short message function entity device that processes the short message service; and the sending module905is configured to send the uplink data to the short message function entity device based on the identification information associated with the session identifier. For example, the receiving module901may be configured to perform any one of steps602,614,620, and628inFIG. 6, steps706,708,720,726, and734inFIG. 7, or steps810,812, and824inFIG. 8; the determining module903may be configured to perform any one of steps603,604,616, and622inFIG. 6, steps707,710,721, and735inFIG. 7, or steps811,814, and826inFIG. 8; and the sending module905may be configured to perform any one of steps606,618,622, and630inFIG. 6, steps706,712,723,728, and736inFIG. 7, or steps810,816, and828inFIG. 8.

The short message function entity device may include a receiving module1001and a sending module1003, as shown inFIG. 10A. For example, the short message function entity device may be implemented by the SMF device108.

In an embodiment, the receiving module1001is configured to receive a first request message from a communications device; the sending module1003is configured to send, to a subscriber data management SDM device based on the first request message, a second request message including the identification information, where the identification information is used to identify the short message function entity device that processes the short message service; the receiving module1001is further configured to receive, from the SDM device, a second response message carrying subscription data of the short message service; and the sending module1003is further configured to send a first response message to the communications device, where the first response message indicates that the short message function entity device successfully registers the short message service. For example, the receiving module1001may be configured to perform any one of steps206,212,222, and225inFIG. 2, steps306,312,318, and321inFIG. 3, steps410,416,422, and430inFIG. 4, or steps514and520inFIG. 5; and the sending module1003may be configured to perform any one of steps208,214, and224inFIG. 2, steps308,314, and320inFIG. 3, steps412,418,424, and432inFIG. 4, or steps516and522inFIG. 5.

In another embodiment, the receiving module1001is configured to receive, from a communications device, a first request message that carries a DNN of a short message service and a session identifier, where the session identifier is used to identify a session for the short message service; the sending module1003is configured to send, to a subscriber data management SDM device based on the first request message, a second request message including the identification information, where the identification information is used to identify the short message function entity device that processes the short message service; the receiving module1001is further configured to receive, from the SDM device, a second response message carrying subscription data of the short message service; and the sending module1003is further configured to send a first response message to the communications device, where the first response message indicates that the short message function entity device successfully registers the short message service. For example, the receiving module1001may be configured to perform any one of steps606,612,622, and625inFIG. 6, steps712,718,724, and732inFIG. 7, or steps816and822inFIG. 8; and the sending module1003may be configured to perform any one of steps608,614, and624inFIG. 6, steps714,720,726, and734inFIG. 7, or steps818and824inFIG. 8.

The subscriber data management device may include a receiving module1101and a sending module1103, as shown inFIG. 11A. For example, the subscriber data management device may be implemented by the SDM device110.

In an embodiment, the receiving module1101is configured to receive a route lookup request message from a short message center, to query identification information, where the identification information is used to identify a short message function entity device that processes a short message service; if the SDM device does not have the identification information, the sending module1103is configured to send a notification message to a communications device, where the notification message includes a cause value: a mobile terminated short message service MT-SMS, and the cause value is used to trigger the communications device to send a first request message to the short message function entity device; the receiving module1101is further configured to receive, from the short message function entity device, a second request message including the identification information; and the sending module1103is further configured to send, to the short message function entity device, a second response message carrying subscription data of the short message service. For example, the receiving module1101may be configured to perform any one of step208inFIG. 2, step308inFIG. 3, steps402and412inFIG. 4, or steps502,506, and516inFIG. 5; and the sending module1103may be configured to perform any one of step212inFIG. 2, step312inFIG. 3, steps406,416,420, and428inFIG. 4, or steps510and520inFIG. 5. In addition, the subscriber data management device may further include a registration module, configured to perform any one of step210inFIG. 2, step310inFIG. 3, step414inFIG. 4, or step518inFIG. 5; the subscriber data management device may further include a judgment module, configured to perform step404inFIG. 4or step504inFIG. 5; and the subscriber data management device may further include a cache module, configured to perform step508inFIG. 5.

In another embodiment, the receiving module1101is configured to receive a route lookup request message from a short message center, to query identification information, where the identification information is used to identify a short message function entity device that processes a short message service; if the SDM device does not have the identification information, the sending module1103is configured to send a session request message to a communications device, where the session request message carries a DNN of the short message service, and the session request message is used to trigger establishment of a session for the short message service; the receiving module1101is further configured to receive, from the short message function entity device, a second request message including the identification information; and the sending module1103is further configured to send, to the short message function entity device, a second response message carrying subscription data of the short message service. For example, the receiving module1101may be configured to perform any one of step608inFIG. 6, steps702and714inFIG. 7, or steps802,806, and818inFIG. 8; and the sending module1103may be configured to perform any one of step612inFIG. 6, steps706,718,722, and730inFIG. 7, or steps810and822inFIG. 8. In addition, the subscriber data management device may further include a registration module, configured to perform any one of step610inFIG. 6, step716inFIG. 7, or step820inFIG. 8; the subscriber data management device may further include a judgment module, configured to perform step704inFIG. 7or step804inFIG. 8; and the subscriber data management device may further include a cache module, configured to perform step808inFIG. 8.

The terminal device may include a sending module1201, as shown inFIG. 12A. For example, the terminal device may be implemented by the terminal device102. The sending module1201is configured to send uplink data and indication information to a communications device, where the indication information is used to indicate that the uplink data belongs to a short message service. Alternatively, the sending module1201is configured to send uplink data and a session identifier to a communications device, where the session identifier is used to identify a session for processing a short message service. For example, the sending module1201may be configured to perform any one of steps202and220inFIG. 2, step302inFIG. 3, or steps602and620inFIG. 6. In addition, the terminal device may further include a receiving module that may be configured to perform any one of steps419and433inFIG. 4, step523inFIG. 5, or steps707,723,728, and736inFIG. 7.

FIG. 9Bis another possible schematic structural diagram of the communications device in the foregoing embodiments. As shown inFIG. 9B, the communications device includes a transceiver902and a processor904. For example, the communications device may be implemented by the AMF device106. The processor904is configured to support the communications device in performing the corresponding functions in the foregoing method. The transceiver902is configured to implement communication between the communications device and the foregoing terminal device/short message function entity device/subscriber data management device. The communications device may further include a memory906, where the memory is configured to be coupled to the processor, and the memory stores a program instruction and data that are necessary for the communications device.

FIG. 10Bis another possible schematic structural diagram of the short message function entity device in the foregoing embodiments. As shown inFIG. 10B, the communications device may include a transceiver1002and a processor1004. For example, the short message function entity device may be implemented by the SMF device108. The processor1004is configured to support the short message function entity device in performing the corresponding functions in the foregoing method. The transceiver1002is configured to implement communication between the short message function entity device and the foregoing communications device/subscriber data management device/short message center. The short message function entity device may further include a memory1006, where the memory is configured to be coupled to the processor, and the memory stores a program instruction and data that are necessary for the short message function entity device.

FIG. 11Bis another possible schematic structural diagram of the subscriber data management device in the foregoing embodiments. As shown inFIG. 11B, the communications device may include a transceiver1102and a processor1104. For example, the subscriber data management device may be implemented by the SDM device110. The processor1104is configured to support the subscriber data management device in performing the corresponding functions in the foregoing method. The transceiver1102is configured to implement communication between the subscriber data management device and the foregoing communications device/short message function entity device/short message center. The subscriber data management device may further include a memory1106, where the memory is configured to be coupled to the processor, and the memory stores a program instruction and data that are necessary for the subscriber data management device.

It may be understood thatFIG. 9B,FIG. 10B, andFIG. 11Bmerely show simplified designs of the foregoing devices. During actual application, each of the foregoing devices may include any quantity of transmitters, receivers, processors, controllers, memories, communications units, or the like, and all the devices that can implement this application fall within the protection scope of this application.

FIG. 12Bis a simplified schematic diagram of another possible design structure of a terminal device in the foregoing embodiments. The terminal device may be the terminal device102inFIG. 1. The terminal device includes a transceiver1206and a controller/processor1202, and may further include a memory1208and a modem processor1204. The transceiver1206adjusts (for example, performs analog conversion, filtering, amplification, or up-conversion on) the output sampling and generates an uplink signal, and the uplink signal is transmitted to the base station in the foregoing embodiments by using an antenna. On a downlink, the antenna receives a downlink signal transmitted by the base station in the foregoing embodiments. The transceiver1206adjusts (for example, performs filtering, amplification, down-conversion, or digitization on) a signal received from the antenna, and provides an input sample. In the modem processor1204, an encoder12041receives service data and a signaling message that are to be sent on an uplink, and processes (for example, performs formatting, encoding, or interleaving on) the service data and the signaling message. A modulator12042further processes (for example, performs symbol mapping or modulation on) encoded service data and an encoded signaling message, and provides an output sample. A demodulator12044processes (for example, demodulates) the input sample and provides a symbol estimate. A decoder12043processes (for example, performs de-interleaving or decoding on) the symbol estimate, and provides decoded data and a decoded signaling message that are sent to the terminal device. The encoder12041, the modulator12042, the demodulator12044, and the decoder12043may be implemented by the integrated modem processor1204. These units perform processing according to radio access technologies (for example, access technologies of an LTE system and another evolved system) used by a radio access network. The controller/processor1202performs control and management on actions of the terminal device, and is configured to perform the processing performed by the terminal device in the foregoing embodiments. For example, the controller/processor1202controls the terminal device to send, by using the transceiver1206, uplink data and indication information to a communications device, where the indication information is used to indicate that the uplink data belongs to a short message service; or send, by using the transceiver1206, uplink data and a session identifier to a communications device, where the session identifier is used to identify a session for processing a short message service. For example, the transceiver1206may be configured to perform any one of steps202and220inFIG. 2, step302inFIG. 3, steps419and433inFIG. 4, step523inFIG. 5, steps602and620inFIG. 6, or steps707,723,728, and736inFIG. 7.

The controller/processor configured to perform functions of the foregoing communications device, short message function entity device, subscriber data management device, and terminal device may be a central processing unit (CPU), a general purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or another programmable logic device, a transistor logic device, a hardware component, or any combination thereof. The controller/processor may implement or execute various example logic blocks, modules, and circuits described with reference to the contents disclosed in this application. Alternatively, the processor may be a combination of processors implementing a computing function, for example, a combination of one or more microprocessors, or a combination of the DSP and a microprocessor.

Method or algorithm steps described in combination with the contents disclosed in this application may be implemented by hardware, or may be implemented by a processor by executing a software instruction. The software instruction may be formed by a corresponding software module. The software module may be stored in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a removable hard disk, a CD-ROM, or a storage medium of any other form known in the art. For example, a storage medium is coupled to a processor, so that the processor can read information from the storage medium or write information into the storage medium. Certainly, the storage medium may be a component of the processor. The processor and the storage medium may be located in the ASIC. In addition, the ASIC may be located in user equipment. Certainly, the processor and the storage medium may exist in the user equipment as discrete components.

In the foregoing specific embodiments, the objectives, technical solutions, and benefits of this application are further described in detail. It should be understood that the foregoing descriptions are merely specific implementations of this application, but are not intended to limit the protection scope of this application. Any modification, equivalent replacement or improvement made based on the technical solutions of this application shall fall within the protection scope of this application.